{"id":51274,"date":"2020-01-25T10:03:00","date_gmt":"2020-01-25T09:03:00","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-gerador-de-turbina-sistema-de-conversao-de-energia-definicao\/"},"modified":"2020-01-25T10:08:50","modified_gmt":"2020-01-25T09:08:50","slug":"o-que-e-gerador-de-turbina-sistema-de-conversao-de-energia-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-gerador-de-turbina-sistema-de-conversao-de-energia-definicao\/","title":{"rendered":"O que \u00e9 gerador de turbina &#8211; Sistema de convers\u00e3o de energia &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">O principal dispositivo do sistema de convers\u00e3o de energia \u00e9 o gerador de turbina. O gerador de turbina est\u00e1 no pr\u00e9dio da turbina e cont\u00e9m a maioria dos principais componentes do ciclo termodin\u00e2mico. Engenharia T\u00e9rmica<\/div>\n<\/div>\n<div><\/div>\n<div><\/div>\n<div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-50 lgc-tablet-grid-50 lgc-mobile-grid-100 lgc-equal-heights  lgc-first\">\n<div class=\"inside-grid-column\">\n<h2><span>Gerador de turbina &#8211; Sistema de convers\u00e3o de energia<\/span><\/h2>\n<p><span>A disposi\u00e7\u00e3o de\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><span>centrais de energia nuclear<\/span><\/a><span>\u00a0compreende duas partes principais:\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/nuclear-island\/\"><span>A\u00a0<\/span><strong><span>ilha nuclear<\/span><\/strong><\/a><span>\u00a0e a\u00a0<\/span><a title=\"Ilha convencional (turbina)\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/conventional-turbine-island\/\"><strong><span>ilha convencional (turbina)<\/span><\/strong><\/a><span>\u00a0.\u00a0A ilha nuclear \u00e9 o cora\u00e7\u00e3o da usina nuclear.\u00a0Por outro lado, a\u00a0<\/span><strong><span>ilha convencional (turbina)<\/span><\/strong><span>\u00a0abriga o componente principal que extrai a energia t\u00e9rmica do vapor pressurizado e a converte em energia el\u00e9trica, o\u00a0<\/span><strong><span>gerador de turbina<\/span><\/strong><span>\u00a0.\u00a0Portanto, tamb\u00e9m \u00e9 conhecido como\u00a0<\/span><strong><span>sistema de convers\u00e3o de energia<\/span><\/strong><span>\u00a0.\u00a0O principal dispositivo do sistema de convers\u00e3o de energia \u00e9\u00a0<\/span><strong><span>o gerador de turbina.\u00a0<\/span><\/strong><span>O gerador de turbina est\u00e1 no pr\u00e9dio da turbina e cont\u00e9m a maioria dos principais componentes do ciclo termodin\u00e2mico.\u00a0Apenas o<\/span><a href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><span>geradores de vapor<\/span><\/a><span>\u00a0est\u00e3o situados no pr\u00e9dio do reator (a ilha nuclear).<\/span><\/p>\n<p><span>Observe que estamos descrevendo o sistema de convers\u00e3o de energia de um reator de \u00e1gua pressurizada (PWR).\u00a0Um\u00a0<\/span><strong><span>reator de \u00e1gua fervente<\/span><\/strong><span>\u00a0(BWR) \u00e9 como um reator de \u00e1gua pressurizada, mas com muitas diferen\u00e7as.\u00a0Os BWRs n\u00e3o possuem nenhum\u00a0<\/span><strong><span>gerador de vapor<\/span><\/strong><span>\u00a0.\u00a0Ao contr\u00e1rio de um PWR, n\u00e3o h\u00e1 loop prim\u00e1rio e secund\u00e1rio.\u00a0Basicamente, a ilha de turbinas de BWRs \u00e9 muito semelhante \u00e0s PWRs.<\/span><\/p>\n<p><span>Como as usinas convencionais (por exemplo, usinas a combust\u00edvel f\u00f3ssil) usam tecnologia muito semelhante para converter energia t\u00e9rmica em energia el\u00e9trica, essa parte da usina nuclear \u00e9 chamada de\u00a0<\/span><strong><span>\u201cilha convencional\u201d<\/span><\/strong><span>\u00a0.\u00a0Em compara\u00e7\u00e3o com as usinas convencionais, a ilha convencional nas usinas nucleares deve atender \u00e0s especifica\u00e7\u00f5es significativamente mais r\u00edgidas de garantia e controle de qualidade que se aplicam at\u00e9 \u00e0s partes convencionais da usina nuclear, devido ao impacto que elas podem ter nos sistemas nucleares.<\/span><\/p>\n<p><span>Os principais componentes do sistema de convers\u00e3o de energia:<\/span><\/p>\n<ul>\n<li><strong><span>Turbina a Vapor<\/span><\/strong><span>\u00a0.\u00a0Uma turbina a vapor \u00e9 um dispositivo que extrai\u00a0<\/span><strong><span>energia t\u00e9rmica<\/span><\/strong><span>\u00a0de vapor pressurizado e a utiliza para realizar\u00a0<\/span><strong><span>trabalhos mec\u00e2nicos<\/span><\/strong><span>\u00a0em um eixo de sa\u00edda rotativo.<\/span><\/li>\n<li><strong><span>Gerador<\/span><\/strong><span>\u00a0.\u00a0Um gerador \u00e9 um dispositivo que converte\u00a0<\/span><strong><span>energia mec\u00e2nica<\/span><\/strong><span>\u00a0da turbina a vapor em\u00a0<\/span><strong><span>energia el\u00e9trica<\/span><\/strong><span>\u00a0.<\/span><\/li>\n<li><a title=\"Gerador de vapor\" href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><strong><span>Gerador de vapor<\/span><\/strong><\/a><span>\u00a0.\u00a0Geradores de vapor s\u00e3o<\/span><strong><span>\u00a0trocadores de calor<\/span><\/strong><span>\u00a0usados \u200b\u200bpara converter<\/span><strong><span>\u00a0\u00e1gua de alimenta\u00e7\u00e3o em vapor a<\/span><\/strong><span>\u00a0partir do calor produzido no<\/span><a href=\"https:\/\/www.reactor-physics.com\/what-is-reactor-core-definition\/\"><span>\u00a0n\u00facleo de<\/span><\/a><span>\u00a0um<a href=\"https:\/\/www.reactor-physics.com\/what-is-reactor-core-definition\/\">\u00a0reator nuclear<\/a>\u00a0.<\/span><\/li>\n<li><strong><span>Condensador<\/span><\/strong><span>\u00a0.\u00a0Um condensador \u00e9 um\u00a0<\/span><strong><span>trocador de calor<\/span><\/strong><span>\u00a0usado para\u00a0<\/span><strong><span>condensar o<\/span><\/strong><span>\u00a0vapor do \u00faltimo est\u00e1gio da turbina.<\/span><\/li>\n<li><strong><span>Sistema de \u00e1gua de alimenta\u00e7\u00e3o de condensado<\/span><\/strong><span>\u00a0.\u00a0Os sistemas de \u00e1gua de alimenta\u00e7\u00e3o de condensado t\u00eam duas fun\u00e7\u00f5es principais.\u00a0<\/span><strong><span>Fornecer<\/span><\/strong><span>\u00a0\u00e1gua de alta qualidade adequada (condensado) ao gerador de vapor e\u00a0<\/span><strong><span>aquecer a \u00e1gua<\/span><\/strong><span>\u00a0(condensado) a uma temperatura pr\u00f3xima da satura\u00e7\u00e3o.<\/span><\/li>\n<li><strong><span>Aquecedor separador de umidade (MSR)<\/span><\/strong><span>\u00a0.\u00a0Os reaquecedores do separador de umidade geralmente s\u00e3o instalados entre a sa\u00edda da turbina de alta press\u00e3o e as entradas da turbina de baixa press\u00e3o para remover a umidade do vapor de exaust\u00e3o da turbina de alta press\u00e3o e reaquecer esse vapor antes de ser admitido nas turbinas LP.<\/span><\/li>\n<li><strong><span>Sistema de refrigera\u00e7\u00e3o<\/span><\/strong><span>\u00a0.\u00a0A principal fun\u00e7\u00e3o do sistema de resfriamento em usinas de energia \u00e9 resfriar o circuito de vapor para condensar o vapor de baixa press\u00e3o e recicl\u00e1-lo.\u00a0\u00c0 medida que o vapor no circuito interno condensa novamente na \u00e1gua, o excesso de calor (res\u00edduo) que \u00e9 removido dele precisa ser descarregado por transfer\u00eancia para o ar ou para um corpo de \u00e1gua.<\/span><\/li>\n<li><strong><span>Sistema de Instrumenta\u00e7\u00e3o e Controle (I&amp;C)<\/span><\/strong><span>\u00a0.\u00a0O sistema de instrumenta\u00e7\u00e3o e controle serve como sistema nervoso central de uma usina nuclear.<\/span><\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-50 lgc-tablet-grid-50 lgc-mobile-grid-100 lgc-equal-heights  lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-youtube su-responsive-media-yes\"><iframe class=\"lazy-loaded\" src=\"https:\/\/www.youtube.com\/embed\/SPg7hOxFItI?\" width=\"340\" height=\"200\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\" data-lazy-type=\"iframe\" data-src=\"https:\/\/www.youtube.com\/embed\/SPg7hOxFItI?\"><\/iframe><\/div>\n<figure id=\"attachment_12524\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-12524\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Nuclear-Island-Conventional-Island-min.jpg\"><img loading=\"lazy\" class=\"size-medium wp-image-12524 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Nuclear-Island-Conventional-Island-min-300x229.jpg\" alt=\"Ilha Nuclear - Ilha Convencional (Turbina)\" width=\"300\" height=\"229\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Nuclear-Island-Conventional-Island-min-300x229.jpg\" \/><\/a><figcaption id=\"caption-attachment-12524\" class=\"wp-caption-text\"><span>O layout das usinas nucleares compreende duas partes principais: a ilha nuclear e a ilha convencional (turbina).<\/span><\/figcaption><\/figure>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17771 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\" alt=\"Ciclo Rankine\" width=\"591\" height=\"897\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\" \/><\/a><br \/>\n<span>Diagrama do ciclo Rankine.\u00a0O ciclo de Rankine recebeu o nome de um engenheiro escoc\u00eas, William John Macquorn Rankine e descreve o desempenho dos sistemas de turbinas a vapor.<\/span><\/p>\n<figure id=\"attachment_17846\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-17846\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min.png\"><img loading=\"lazy\" class=\"size-large wp-image-17846 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min-1024x529.png\" alt=\"Turbina a vapor de 3000MWth PWR t\u00edpico\" width=\"669\" height=\"346\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min-1024x529.png\" \/><\/a><figcaption id=\"caption-attachment-17846\" class=\"wp-caption-text\"><span>Esquema de uma turbina a vapor de um t\u00edpico 3000MWth PWR.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Princ\u00edpio de Opera\u00e7\u00e3o do Gerador de Turbina &#8211; Gera\u00e7\u00e3o de Eletricidade<\/span><\/h2>\n<p>A maioria das\u00a0<strong>usinas nucleares<\/strong>\u00a0opera um\u00a0<strong>gerador de turbina de eixo \u00fanico<\/strong>\u00a0que consiste em uma\u00a0<strong>turbina HP de v\u00e1rios est\u00e1gios\u00a0<\/strong>e\u00a0<strong>tr\u00eas turbinas LP de v\u00e1rios est\u00e1gios paralelos<\/strong>\u00a0, um gerador principal e um excitador. <strong>\u00a0A turbina HP<\/strong>\u00a0geralmente \u00e9 uma turbina de acci\u00f3n de fluxo duplo (ou tipo de rea\u00e7\u00e3o) com cerca de 10 est\u00e1gios com p\u00e1s encobertas e produz cerca de 30-40% da pot\u00eancia bruta da unidade da usina.\u00a0<strong>Turbinas LP <\/strong>geralmente s\u00e3o turbinas de rea\u00e7\u00e3o de fluxo duplo com cerca de 5-8 est\u00e1gios (com p\u00e1s encobertas e com p\u00e1s independentes dos \u00faltimos 3 est\u00e1gios).\u00a0As turbinas LP produzem aproximadamente 60-70% da produ\u00e7\u00e3o bruta de energia da unidade da usina.\u00a0Cada rotor de turbina \u00e9 montado em dois mancais, ou seja, h\u00e1 mancais duplos entre cada m\u00f3dulo de turbina.<\/p>\n<figure id=\"attachment_17846\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-17846\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min.png\"><img loading=\"lazy\" class=\"size-large wp-image-17846 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min-1024x529.png\" alt=\"Turbina a vapor de 3000MWth PWR t\u00edpico\" width=\"669\" height=\"346\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Steam-Turbine-scheme-min-1024x529.png\" \/><\/a><figcaption id=\"caption-attachment-17846\" class=\"wp-caption-text\"><span>Esquema de uma turbina a vapor de um t\u00edpico 3000MWth PWR.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Do gerador de vapor \u00e0s principais linhas de vapor &#8211; Evapora\u00e7\u00e3o<\/span><\/h2>\n<figure id=\"attachment_407\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-407\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR.gif\"><img loading=\"lazy\" class=\"size-full wp-image-407 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR.gif\" alt=\"Gerador de vapor - vertical\" width=\"266\" height=\"357\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR.gif\" \/><\/a><figcaption id=\"caption-attachment-407\" class=\"wp-caption-text\"><span>Gerador de vapor &#8211; vertical<\/span><\/figcaption><\/figure>\n<p><span>O sistema de convers\u00e3o de energia do\u00a0<\/span><a title=\"PWR - Reator de \u00e1gua pressurizada\" href=\"https:\/\/www.nuclear-power.com\/pwr-pressurized-water-reactor\/\"><span>PWR<\/span><\/a><span>\u00a0t\u00edpico\u00a0\u00a0come\u00e7a nos\u00a0<\/span><a title=\"Gerador de vapor\" href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><span>geradores de vapor<\/span><\/a><span>\u00a0em seus lados da carca\u00e7a.\u00a0Geradores de vapor s\u00e3o\u00a0<\/span><strong><span>trocadores de calor<\/span><\/strong><span>\u00a0usados \u200b\u200bpara converter\u00a0<\/span><strong><span>\u00e1gua de alimenta\u00e7\u00e3o em vapor a<\/span><\/strong><span>\u00a0partir do calor produzido no\u00a0<\/span><a href=\"https:\/\/www.reactor-physics.com\/what-is-reactor-core-definition\/\"><span>n\u00facleo de<\/span><\/a><span>\u00a0um\u00a0<a href=\"https:\/\/www.reactor-physics.com\/what-is-reactor-core-definition\/\">reator nuclear<\/a>\u00a0.\u00a0A \u00e1gua de alimenta\u00e7\u00e3o (circuito secund\u00e1rio) \u00e9 aquecida de\u00a0<\/span><strong><span>~ 230 \u00b0 C a 500 \u00b0 F<\/span><\/strong><span>\u00a0(fluido pr\u00e9-aquecido por regeneradores) at\u00e9 o ponto de ebuli\u00e7\u00e3o desse fluido\u00a0<\/span><strong><span>(280 \u00b0 C; 536 \u00b0 F; 6,5MPa)<\/span><\/strong><span>\u00a0.\u00a0O calor \u00e9 transferido atrav\u00e9s das paredes desses tubos para o refrigerante secund\u00e1rio de baixa press\u00e3o localizado no lado secund\u00e1rio do trocador, onde o refrigerante evapora para vapor pressurizado\u00a0<\/span><strong><span>(\u00a0<\/span><\/strong><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><strong><span>vapor saturado<\/span><\/strong><\/a><strong><span>\u00a0280 \u00b0 C; 536 \u00b0 F; 6,5 MPa)<\/span><\/strong><span>.\u00a0O vapor saturado sai do gerador de vapor atrav\u00e9s de uma sa\u00edda de vapor e continua at\u00e9 as\u00a0<\/span><strong><span>principais linhas de vapor<\/span><\/strong><span>\u00a0e depois para a\u00a0<\/span><strong><span>turbina<\/span><\/strong><span>\u00a0a\u00a0<strong>vapor<\/strong>\u00a0.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/From-Steam-Generator-to-Main-Steam-Lines-min.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-17845 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/From-Steam-Generator-to-Main-Steam-Lines-min-241x300.png\" alt=\"Gerador de vapor para as principais linhas de vapor\" width=\"241\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/From-Steam-Generator-to-Main-Steam-Lines-min-241x300.png\" \/><\/a><span>Essas principais linhas de vapor s\u00e3o reticuladas (por exemplo, atrav\u00e9s de um tubo coletor de vapor) perto da turbina para garantir que a diferen\u00e7a de press\u00e3o entre qualquer um dos geradores de vapor n\u00e3o exceda um valor espec\u00edfico, mantendo assim o equil\u00edbrio do sistema e garantindo a remo\u00e7\u00e3o uniforme de calor do sistema de refrigera\u00e7\u00e3o do reator ( RCS).\u00a0O vapor flui atrav\u00e9s das\u00a0<\/span><strong><span>principais v\u00e1lvulas de isolamento da linha de vapor<\/span><\/strong><span>\u00a0(MSIVs), que s\u00e3o muito importantes do ponto de vista da seguran\u00e7a, para a turbina de alta press\u00e3o.\u00a0Directamente na entrada da turbina a vapor, existem\u00a0<\/span><strong><span>v\u00e1lvulas de estrangulamento-stop<\/span><\/strong><span>\u00a0e\u00a0<\/span><strong><span>v\u00e1lvulas de controlo<\/span><\/strong><span>\u00a0.\u00a0O controle da turbina \u00e9 obtido variando as aberturas dessas v\u00e1lvulas.\u00a0No caso de uma\u00a0<\/span><strong><span>viagem de turbina<\/span><\/strong><span>, o suprimento de vapor deve ser isolado muito rapidamente, geralmente na fra\u00e7\u00e3o de segundo, para que as v\u00e1lvulas de parada operem com rapidez e confiabilidade.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Das v\u00e1lvulas de turbina ao condensador &#8211; expans\u00e3o<\/span><\/h2>\n<figure id=\"attachment_17781\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17781\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17781 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram-300x276.png\" alt=\"Ciclo de Rankine - diagrama de Ts\" width=\"300\" height=\"276\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram-300x276.png\" \/><\/a><figcaption id=\"caption-attachment-17781\" class=\"wp-caption-text\"><span>Ciclo de Rankine &#8211; diagrama de Ts<\/span><\/figcaption><\/figure>\n<p><span>Normalmente, a maioria das\u00a0<\/span><strong><span>usinas nucleares<\/span><\/strong><span>\u00a0opera\u00a0<\/span><strong><span>turbinas a vapor de condensa\u00e7\u00e3o de v\u00e1rios est\u00e1gios<\/span><\/strong><span>\u00a0.\u00a0Nessas turbinas, o est\u00e1gio de alta press\u00e3o recebe\u00a0<\/span><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0(esse vapor \u00e9 quase o vapor saturado &#8211; x = 0,995 &#8211; ponto C na figura;\u00a0<\/span><strong><span>6 MPa<\/span><\/strong><span>\u00a0; 275,6 \u00b0 C) de um gerador de vapor e o esgota para o separador-reaquecedor de umidade (MSR &#8211; ponto D).\u00a0O vapor deve ser reaquecido para evitar danos que podem ser causados \u200b\u200b\u00e0s p\u00e1s da turbina a vapor por vapor de\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/vapor-quality-dryness-fraction\/\"><span>baixa qualidade<\/span><\/a><span>.\u00a0O alto teor de got\u00edculas de \u00e1gua pode causar o r\u00e1pido impacto e a eros\u00e3o das p\u00e1s, que ocorre quando a \u00e1gua condensada \u00e9 jateada sobre as p\u00e1s.\u00a0Para evitar isso, drenos de condensado s\u00e3o instalados na tubula\u00e7\u00e3o de vapor que leva \u00e0 turbina.\u00a0O vapor sem umidade \u00e9 superaquecido pelo vapor de extra\u00e7\u00e3o do est\u00e1gio de alta press\u00e3o da turbina e pelo vapor diretamente das principais linhas de vapor.<\/span><\/p>\n<figure id=\"attachment_17852\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17852\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Main-Turbine-key-parameters.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17852 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Main-Turbine-key-parameters-234x300.png\" alt=\"Fonte: TVO - NKP Olkiluoto 3 www.tvo.fi\/uploads\/julkaisut\/tiedostot\/ydinvoimalayks_OL3_ENG.pdf\" width=\"234\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Main-Turbine-key-parameters-234x300.png\" \/><\/a><figcaption id=\"caption-attachment-17852\" class=\"wp-caption-text\"><span>Fonte: TVO &#8211; NKP Olkiluoto 3 www.tvo.fi\/uploads\/julkaisut\/tiedostot\/ydinvoimalayks_OL3_ENG.pdf<\/span><\/figcaption><\/figure>\n<p><span>O vapor de aquecimento \u00e9 condensado nos tubos e drenado para o sistema de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0O reaquecedor aquece o vapor (ponto D) e, em seguida, o vapor \u00e9 direcionado para o est\u00e1gio de baixa press\u00e3o da turbina a vapor, onde se expande (pontos E a F).\u00a0O vapor exaurido condensa no condensador e est\u00e1 a uma press\u00e3o bem abaixo da atmosf\u00e9rica (press\u00e3o absoluta de\u00a0<\/span><strong><span>0,008 MPa<\/span><\/strong><span>\u00a0) e est\u00e1 em um estado parcialmente condensado (ponto F), tipicamente com uma qualidade pr\u00f3xima a 90%.\u00a0Os est\u00e1gios de alta press\u00e3o e baixa press\u00e3o da turbina geralmente est\u00e3o no mesmo eixo para acionar um gerador comum, mas eles t\u00eam casos separados.\u00a0O gerador principal produz energia el\u00e9trica, que \u00e9 fornecida \u00e0 rede el\u00e9trica.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Wet-Steam-Turbine-Expansion-min.png\"><img loading=\"lazy\" class=\"aligncenter size-large wp-image-17844 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Wet-Steam-Turbine-Expansion-min-1024x388.png\" alt=\"Turbina a Vapor \u00damida - Expans\u00e3o\" width=\"669\" height=\"253\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Wet-Steam-Turbine-Expansion-min-1024x388.png\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-divider su-divider-style-dotted\"><\/div>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<h2><span>Do Condensador \u00e0s Bombas de Condensado &#8211; Condensa\u00e7\u00e3o<\/span><\/h2>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-17843 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min-300x146.png\" alt=\"Condensador - Aquecedores de LP - Desaerador\" width=\"300\" height=\"146\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min-300x146.png\" \/><\/a><span>O condensador principal condensa o vapor de exaust\u00e3o dos est\u00e1gios de baixa press\u00e3o da turbina principal e tamb\u00e9m do sistema de despejo de vapor.\u00a0O vapor exaurido \u00e9 condensado passando sobre os tubos que cont\u00eam \u00e1gua do sistema de resfriamento.<\/span><\/p>\n<p><span>A press\u00e3o no interior do\u00a0<\/span><strong><span>condensador<\/span><\/strong><span>\u00a0\u00e9 determinada pela temperatura do ar ambiente (ou seja, a temperatura da \u00e1gua no sistema de refrigera\u00e7\u00e3o) e por\u00a0<\/span><strong><span>ejetores de vapor<\/span><\/strong><span>\u00a0ou\u00a0<\/span><strong><span>bombas de v\u00e1cuo<\/span><\/strong><span>\u00a0, que puxam os gases (n\u00e3o condens\u00e1veis) do condensador de superf\u00edcie e os lan\u00e7am para a atmosfera.<\/span><\/p>\n<p><span>A menor press\u00e3o vi\u00e1vel do condensador \u00e9 a press\u00e3o de satura\u00e7\u00e3o correspondente \u00e0 temperatura ambiente (por exemplo, press\u00e3o absoluta de\u00a0<\/span><strong><span>0,008 MPa,<\/span><\/strong><span>\u00a0que corresponde a\u00a0<\/span><strong><span>41,5 \u00b0 C<\/span><\/strong><span>\u00a0).\u00a0Observe que sempre h\u00e1 uma diferen\u00e7a de temperatura entre (em torno de\u00a0<\/span><strong><span>\u0394T = 14 \u00b0 C<\/span><\/strong><span>\u00a0) a temperatura do condensador e a temperatura ambiente, que se origina do tamanho finito e da efici\u00eancia dos condensadores.\u00a0Como nem o condensador \u00e9 um trocador de calor 100% eficiente, sempre h\u00e1 uma diferen\u00e7a de temperatura entre a temperatura de satura\u00e7\u00e3o (lado secund\u00e1rio) e a temperatura do l\u00edquido de arrefecimento no sistema de refrigera\u00e7\u00e3o.\u00a0Al\u00e9m disso, h\u00e1 uma inefici\u00eancia de projeto, que diminui a efici\u00eancia geral da turbina.\u00a0Idealmente, o vapor descarregado no condensador n\u00e3o teria\u00a0<\/span><strong><span>sub-resfriamento<\/span><\/strong><span>.\u00a0Mas os condensadores reais s\u00e3o projetados para sub-resfriar o l\u00edquido em alguns graus Celsius, a fim de evitar a\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/centrifugal-pumps\/cavitation\/suction-cavitation\/\"><strong><span>cavita\u00e7\u00e3o de suc\u00e7\u00e3o<\/span><\/strong><\/a><span>\u00a0nas bombas de condensado.\u00a0Por\u00e9m, esse sub-resfriamento aumenta a inefici\u00eancia do ciclo, porque \u00e9 necess\u00e1ria mais energia para reaquecer a \u00e1gua.<\/span><\/p>\n<figure id=\"attachment_17767\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17767\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-condenser-pressure-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17767 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-condenser-pressure-min-300x300.png\" alt=\"Ciclo Rankine - press\u00e3o do condensador\" width=\"300\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-condenser-pressure-min-300x300.png\" \/><\/a><figcaption id=\"caption-attachment-17767\" class=\"wp-caption-text\"><span>Diminuir a press\u00e3o de escape da turbina aumenta o trabalho l\u00edquido por ciclo, mas tamb\u00e9m diminui a qualidade do vapor de sa\u00edda.<\/span><\/figcaption><\/figure>\n<p><span>O objetivo de manter a menor press\u00e3o pr\u00e1tica de exaust\u00e3o da turbina \u00e9 a principal raz\u00e3o para incluir o condensador em uma usina termel\u00e9trica.\u00a0O condensador fornece um v\u00e1cuo que maximiza a energia extra\u00edda do vapor, resultando em um aumento significativo no trabalho l\u00edquido e na efici\u00eancia t\u00e9rmica.\u00a0Mas tamb\u00e9m este par\u00e2metro (press\u00e3o do condensador) tem seus limites de engenharia:<\/span><\/p>\n<ul>\n<li><span>Diminuir a press\u00e3o de exaust\u00e3o da turbina diminui a qualidade do vapor (ou fra\u00e7\u00e3o de secura).\u00a0Em algum momento, a expans\u00e3o deve ser encerrada para evitar danos que podem ser causados \u200b\u200b\u00e0s p\u00e1s da turbina a vapor por vapor de\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/vapor-quality-dryness-fraction\/\"><span>baixa qualidade<\/span><\/a><span>\u00a0.<\/span><\/li>\n<li><span>Diminuir a press\u00e3o de exaust\u00e3o da turbina aumenta significativamente o volume espec\u00edfico de vapor exaurido, o que requer grandes l\u00e2minas nas \u00faltimas fileiras do est\u00e1gio de baixa press\u00e3o da turbina a vapor.<\/span><\/li>\n<\/ul>\n<p><span>Em uma\u00a0<\/span><strong><span>turbina a vapor \u00famida<\/span><\/strong><span>\u00a0t\u00edpica\u00a0, o vapor exaurido condensa no condensador e est\u00e1 a uma press\u00e3o bem abaixo da atmosf\u00e9rica (press\u00e3o absoluta de\u00a0<\/span><strong><span>0,008 MPa,<\/span><\/strong><span>\u00a0que corresponde a 41,5 \u00b0 C).\u00a0Este vapor est\u00e1 em um estado parcialmente condensado (ponto F), normalmente com uma qualidade pr\u00f3xima a 90%.\u00a0Observe que a press\u00e3o dentro do condensador tamb\u00e9m depende das condi\u00e7\u00f5es atmosf\u00e9ricas do ambiente:<\/span><\/p>\n<ul>\n<li><span>temperatura do ar, press\u00e3o e umidade em caso de resfriamento na atmosfera<\/span><\/li>\n<li><span>temperatura da \u00e1gua e vaz\u00e3o em caso de resfriamento em um rio ou mar<\/span><\/li>\n<\/ul>\n<p><span>Um aumento na temperatura ambiente causa um aumento proporcional na press\u00e3o do vapor exaurido (\u00a0<\/span><strong><span>\u0394T = 14 \u00b0 C<\/span><\/strong><span>\u00a0\u00e9 geralmente uma constante), portanto, a efici\u00eancia t\u00e9rmica do sistema de convers\u00e3o de energia diminui.\u00a0Em outras palavras, a\u00a0<\/span><strong><span>produ\u00e7\u00e3o el\u00e9trica<\/span><\/strong><span>\u00a0de uma usina\u00a0<\/span><strong><span>pode variar de acordo<\/span><\/strong><span>\u00a0com as\u00a0<\/span><strong><span>condi\u00e7\u00f5es ambientais<\/span><\/strong><span>\u00a0, enquanto a energia t\u00e9rmica permanece constante.<\/span><\/p>\n<p><span>O vapor condensado (agora chamado de condensado) \u00e9 coletado na c\u00e2mara quente do condensador.\u00a0A c\u00e2mara quente do condensador tamb\u00e9m fornece uma capacidade de armazenamento de \u00e1gua, necess\u00e1ria para fins operacionais, como a composi\u00e7\u00e3o da \u00e1gua de alimenta\u00e7\u00e3o.\u00a0O condensado (l\u00edquido saturado ou ligeiramente sub-resfriado) \u00e9 entregue \u00e0 bomba de condensado e depois bombeado por bombas de condensado para o desaerador atrav\u00e9s do sistema de aquecimento de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0As bombas de condensado aumentam a press\u00e3o normalmente para cerca de p = 1-2 MPa.\u00a0Geralmente, existem quatro bombas de condensado centr\u00edfugas com um ter\u00e7o da capacidade com cabe\u00e7alhos comuns de suc\u00e7\u00e3o e descarga.\u00a0Normalmente, tr\u00eas bombas est\u00e3o em opera\u00e7\u00e3o e uma no backup.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\"><\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<h2><span>Das bombas de condensado \u00e0s bombas de \u00e1gua de alimenta\u00e7\u00e3o &#8211; Regenera\u00e7\u00e3o de calor<\/span><\/h2>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-17843 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min-300x146.png\" alt=\"Condensador - Aquecedores de LP - Desaerador\" width=\"300\" height=\"146\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Condenser-LP-Heaters-Deaerator-min-300x146.png\" \/><\/a><span>O\u00a0<\/span><strong><span>condensado<\/span><\/strong><span>\u00a0das\u00a0<\/span><strong><span>bombas de condensado<\/span><\/strong><span>\u00a0passa ent\u00e3o por v\u00e1rios est\u00e1gios dos\u00a0<\/span><strong><span>aquecedores de \u00e1gua de alimenta\u00e7\u00e3o<\/span><\/strong><span>\u00a0de\u00a0<strong>baixa press\u00e3o<\/strong>\u00a0, nos quais a temperatura do condensado \u00e9 aumentada pela transfer\u00eancia de calor do vapor extra\u00eddo das turbinas de baixa press\u00e3o.\u00a0Normalmente, existem tr\u00eas ou quatro est\u00e1gios de aquecedores de \u00e1gua de alimenta\u00e7\u00e3o de baixa press\u00e3o conectados na cascata.\u00a0O condensado sai dos aquecedores de \u00e1gua de alimenta\u00e7\u00e3o de baixa press\u00e3o a aproximadamente p = 1 MPa, t = 150 \u00b0 C e entra no\u00a0<\/span><strong><span>desaerador<\/span><\/strong><span>.\u00a0O sistema principal de condensado tamb\u00e9m cont\u00e9m um sistema mec\u00e2nico de purifica\u00e7\u00e3o de condensado para remover impurezas.\u00a0Os aquecedores de \u00e1gua de alimenta\u00e7\u00e3o s\u00e3o auto-regul\u00e1veis.\u00a0Isso significa que quanto maior o fluxo de \u00e1gua de alimenta\u00e7\u00e3o, maior a taxa de absor\u00e7\u00e3o de calor do vapor e maior o fluxo de vapor de extra\u00e7\u00e3o.<\/span><\/p>\n<p><span>Existem v\u00e1lvulas de reten\u00e7\u00e3o nas linhas de vapor de extra\u00e7\u00e3o entre os aquecedores de \u00e1gua de alimenta\u00e7\u00e3o e a turbina.\u00a0Essas v\u00e1lvulas de reten\u00e7\u00e3o impedem o fluxo reverso de vapor ou \u00e1gua em caso de disparo da turbina, o que causa uma r\u00e1pida diminui\u00e7\u00e3o da press\u00e3o no interior da turbina.\u00a0Qualquer \u00e1gua que entre na turbina dessa maneira pode causar s\u00e9rios danos \u00e0s p\u00e1s da turbina.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Desaerador<\/span><\/h2>\n<figure id=\"attachment_17856\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17856\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Deaerator.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17856 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Deaerator-285x300.png\" alt=\"Desaerador\" width=\"285\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Deaerator-285x300.png\" \/><\/a><figcaption id=\"caption-attachment-17856\" class=\"wp-caption-text\"><span>Um diagrama esquem\u00e1tico de um desaerador t\u00edpico do tipo bandeja.\u00a0Fonte: wikipedia.org Licen\u00e7a: CC BY-SA 3.0<\/span><\/figcaption><\/figure>\n<p><span>Em geral, um\u00a0<\/span><strong><span>desaerador<\/span><\/strong><span>\u00a0\u00e9 um dispositivo usado para a remo\u00e7\u00e3o de oxig\u00eanio e outros gases dissolvidos da \u00e1gua de alimenta\u00e7\u00e3o para os geradores de vapor.\u00a0O\u00a0<\/span><strong><span>desaerador<\/span><\/strong><span>\u00a0faz parte do sistema de aquecimento de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0Geralmente est\u00e1 situado entre o \u00faltimo aquecedor de baixa press\u00e3o e as bombas de refor\u00e7o de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0Em particular, o oxig\u00eanio dissolvido no gerador de vapor pode causar s\u00e9rios danos \u00e0 corros\u00e3o, anexando-se \u00e0s paredes da tubula\u00e7\u00e3o de metal e outros equipamentos met\u00e1licos e formando \u00f3xidos (ferrugem).\u00a0Al\u00e9m disso, o di\u00f3xido de carbono dissolvido combina-se com a \u00e1gua para formar \u00e1cido carb\u00f4nico que causa corros\u00e3o adicional.<\/span><\/p>\n<p><span>No\u00a0<\/span><strong><span>desaerador<\/span><\/strong><span>\u00a0, o condensado \u00e9 aquecido a condi\u00e7\u00f5es saturadas, geralmente pelo vapor extra\u00eddo da turbina a vapor.\u00a0O vapor de extra\u00e7\u00e3o \u00e9 misturado no desaerador por um sistema de bicos de pulveriza\u00e7\u00e3o e bandejas em cascata entre as quais o vapor penetra.\u00a0Quaisquer gases dissolvidos no condensado s\u00e3o liberados nesse processo e removidos do desaerador por ventila\u00e7\u00e3o para a atmosfera ou para o condensador principal.\u00a0Diretamente abaixo do\u00a0<\/span><strong><span>desaerador<\/span><\/strong><span>\u00a0est\u00e1 o\u00a0<\/span><strong><span>tanque de armazenamento de \u00e1gua de alimenta\u00e7\u00e3o<\/span><\/strong><span>, em que uma grande quantidade de \u00e1gua de alimenta\u00e7\u00e3o \u00e9 armazenada em condi\u00e7\u00f5es pr\u00f3ximas \u00e0 satura\u00e7\u00e3o.\u00a0No evento de disparo da turbina, essa \u00e1gua de alimenta\u00e7\u00e3o pode ser fornecida aos geradores de vapor para manter o invent\u00e1rio de \u00e1gua necess\u00e1rio durante o per\u00edodo transit\u00f3rio.\u00a0O desaerador e o tanque de armazenamento geralmente est\u00e3o localizados em uma eleva\u00e7\u00e3o elevada no sal\u00e3o da turbina para garantir uma\u00a0<\/span><a title=\"Cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/centrifugal-pumps\/net-positive-suction-head\/\"><span>cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida<\/span><\/a><span>\u00a0(NPSH)\u00a0adequada\u00a0na entrada das bombas de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0<\/span><strong><span>O NPSH<\/span><\/strong><span>\u00a0\u00e9 usado para medir\u00a0<\/span><strong><span>a proximidade de<\/span><\/strong><span>\u00a0um fluido a condi\u00e7\u00f5es saturadas.\u00a0Baixar a press\u00e3o no lado da suc\u00e7\u00e3o pode induzir\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/centrifugal-pumps\/cavitation\/\"><strong><span>cavita\u00e7\u00e3o<\/span><\/strong><\/a><span>\u00a0.\u00a0Esse arranjo minimiza o risco de cavita\u00e7\u00e3o na bomba.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Das bombas de \u00e1gua de alimenta\u00e7\u00e3o ao gerador de vapor<\/span><\/h2>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Feedwater-Pumps-HP-Heaters-min.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-17847 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Feedwater-Pumps-HP-Heaters-min-300x298.png\" alt=\"Bombas de \u00e1gua de alimenta\u00e7\u00e3o - Aquecedores HP\" width=\"300\" height=\"298\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Feedwater-Pumps-HP-Heaters-min-300x298.png\" \/><\/a><span>O sistema de\u00a0<\/span><strong><span>bombas<\/span><\/strong><span>\u00a0de\u00a0<strong>\u00e1gua<\/strong>\u00a0de\u00a0<strong>alimenta\u00e7\u00e3o<\/strong>\u00a0geralmente cont\u00e9m tr\u00eas linhas paralelas (\u00a0<\/span><strong><span>3 \u00d7 50%<\/span><\/strong><span>\u00a0) de bombas de \u00e1gua de alimenta\u00e7\u00e3o com cabe\u00e7alhos comuns de suc\u00e7\u00e3o e descarga.\u00a0Cada bomba de \u00e1gua de alimenta\u00e7\u00e3o consiste no\u00a0<\/span><strong><span>refor\u00e7o<\/span><\/strong><span>\u00a0e na\u00a0<\/span><strong><span>bomba de \u00e1gua de alimenta\u00e7\u00e3o principal<\/span><\/strong><span>\u00a0.\u00a0As bombas de \u00e1gua de alimenta\u00e7\u00e3o (geralmente acionadas por turbinas a vapor) aumentam a press\u00e3o do condensado (~ 1MPa) para a press\u00e3o no gerador de vapor (~ 6,5MPa).<\/span><\/p>\n<p><span>As\u00a0<\/span><strong><span>bombas auxiliares<\/span><\/strong><span>\u00a0fornecem a press\u00e3o de suc\u00e7\u00e3o principal necess\u00e1ria da bomba de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0Essas bombas (ambas as bombas de \u00e1gua de alimenta\u00e7\u00e3o) s\u00e3o normalmente bombas de alta press\u00e3o (geralmente do\u00a0<\/span><a title=\"Bombas centr\u00edfugas\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-bomba-centrifuga-definicao\/\"><span>tipo bomba centr\u00edfuga<\/span><\/a><span>\u00a0) que s\u00e3o aspiradas pelo tanque de armazenamento de \u00e1gua do desaerador, montado diretamente abaixo do desaerador, e fornecem as principais bombas de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0A descarga de \u00e1gua das bombas de \u00e1gua de alimenta\u00e7\u00e3o flui atrav\u00e9s dos\u00a0<\/span><strong><span>aquecedores de \u00e1gua de alimenta\u00e7\u00e3o de alta press\u00e3o<\/span><\/strong><span>\u00a0, entra na\u00a0<\/span><a title=\"Constru\u00e7\u00e3o de conten\u00e7\u00e3o\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/containment-building\/\"><span>conten\u00e7\u00e3o<\/span><\/a><span>\u00a0e depois flui para os\u00a0<\/span><a title=\"Gerador de vapor\" href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><span>geradores de vapor<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><span>O fluxo de \u00e1gua de alimenta\u00e7\u00e3o para cada gerador de vapor \u00e9 controlado por\u00a0<\/span><strong><span>v\u00e1lvulas reguladoras de \u00e1gua<\/span><\/strong><span>\u00a0de\u00a0<strong>alimenta\u00e7\u00e3o<\/strong>\u00a0(\u00a0<\/span><strong><span>FRVs<\/span><\/strong><span>\u00a0) em cada linha de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0O regulador \u00e9 controlado automaticamente pelo n\u00edvel do gerador de vapor, fluxo de vapor e fluxo de \u00e1gua de alimenta\u00e7\u00e3o.<\/span><\/p>\n<p><span>Os\u00a0<\/span><strong><span>aquecedores de \u00e1gua de alimenta\u00e7\u00e3o de alta press\u00e3o<\/span><\/strong><span>\u00a0s\u00e3o aquecidos pelo vapor de extra\u00e7\u00e3o da turbina de alta press\u00e3o, HP Turbine.\u00a0Os drenos dos aquecedores de \u00e1gua de alimenta\u00e7\u00e3o de alta press\u00e3o s\u00e3o geralmente encaminhados para o desaerador.<\/span><\/p>\n<figure id=\"attachment_407\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-407\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR.gif\"><img loading=\"lazy\" class=\"size-medium wp-image-407 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR-223x300.gif\" alt=\"Gerador de vapor - vertical\" width=\"223\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR-223x300.gif\" \/><\/a><figcaption id=\"caption-attachment-407\" class=\"wp-caption-text\"><span>Gerador de vapor &#8211; vertical<\/span><\/figcaption><\/figure>\n<p><span>A \u00e1gua de alimenta\u00e7\u00e3o (\u00a0<\/span><strong><span>\u00e1gua 230 \u00b0 C; 446 \u00b0 F; 6,5MPa<\/span><\/strong><span>\u00a0) \u00e9 bombeada para\u00a0<\/span><strong><span>o gerador de vapor<\/span><\/strong><span>\u00a0atrav\u00e9s da entrada de \u00e1gua de alimenta\u00e7\u00e3o.\u00a0No gerador de vapor, a \u00e1gua de alimenta\u00e7\u00e3o (circuito secund\u00e1rio) \u00e9 aquecida de\u00a0<\/span><strong><span>~ 230 \u00b0 C 446 \u00b0 F<\/span><\/strong><span>\u00a0at\u00e9 o ponto de ebuli\u00e7\u00e3o desse fluido\u00a0<\/span><strong><span>(280 \u00b0 C; 536 \u00b0 F; 6,5MPa)<\/span><\/strong><span>\u00a0.\u00a0A \u00e1gua de alimenta\u00e7\u00e3o \u00e9 ent\u00e3o evaporada e o vapor pressurizado\u00a0<\/span><strong><span>(<\/span><\/strong><span>\u00a0vapor\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/dry-steam\/\"><strong><span>saturado<\/span><\/strong><\/a><strong><span>\u00a0280 \u00b0 C; 536 \u00b0 F; 6,5 MPa)<\/span><\/strong><span>\u00a0sai do gerador de vapor pela sa\u00edda de vapor e continua at\u00e9 a turbina a vapor, completando assim o ciclo.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\"><\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<h2><span>Efici\u00eancia t\u00e9rmica de turbinas a vapor<\/span><\/h2>\n<p><span>Em geral, a\u00a0<a title=\"Efici\u00eancia t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-definicao\/\"><strong>efici\u00eancia t\u00e9rmica<\/strong><\/a><a title=\"Efici\u00eancia t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-definicao\/\">\u00a0,\u00a0<\/a><a title=\"Efici\u00eancia t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-definicao\/\"><strong><em>\u03b7\u00a0<\/em><\/strong><\/a><a title=\"Efici\u00eancia t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-definicao\/\"><strong><em><sub>th<\/sub><\/em><\/strong><\/a>\u00a0, de qualquer motor de calor \u00e9 definida como a raz\u00e3o entre o\u00a0<a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-trabalho-em-termodinamica-definicao\/\">trabalho<\/a>\u00a0que faz,\u00a0<strong>W<\/strong>\u00a0, para o\u00a0<a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-calor-na-fisica-calor-definicao\/\">calor<\/a>\u00a0de entrada a uma temperatura elevada, Q\u00a0<sub>H<\/sub>\u00a0.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-1.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-16945 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-1.png\" alt=\"f\u00f3rmula de efici\u00eancia t\u00e9rmica - 1\" width=\"125\" height=\"82\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-1.png\" \/><\/a><\/p>\n<p><span>A\u00a0<\/span><strong><span>efici\u00eancia t\u00e9rmica<\/span><\/strong><span>\u00a0,\u00a0<\/span><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>th<\/span><\/sub><\/em><\/strong><span>\u00a0, representa a fra\u00e7\u00e3o de\u00a0<\/span><strong><span>calor<\/span><\/strong><span>\u00a0,\u00a0<\/span><strong><span>Q\u00a0<\/span><\/strong><strong><sub><span>H<\/span><\/sub><\/strong><span>\u00a0, que \u00e9 convertida\u00a0<\/span><strong><span>em trabalho<\/span><\/strong><span>\u00a0.\u00a0Como a energia \u00e9 conservada de acordo com a\u00a0<\/span><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-primeira-lei-da-termodinamica-definicao\/\"><strong><span>primeira lei da termodin\u00e2mica<\/span><\/strong><\/a><span>\u00a0e a energia n\u00e3o pode ser convertida para funcionar completamente, a entrada de calor, Q\u00a0<\/span><sub><span>H<\/span><\/sub><span>\u00a0, deve ser igual ao trabalho realizado, W, mais o calor que deve ser dissipado como\u00a0<\/span><strong><span>calor residual Q\u00a0<\/span><\/strong><strong><sub><span>C<\/span><\/sub><\/strong><span>\u00a0no meio Ambiente.\u00a0Portanto, podemos reescrever a f\u00f3rmula da efici\u00eancia t\u00e9rmica como:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-2.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-16944 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-2.png\" alt=\"f\u00f3rmula de efici\u00eancia t\u00e9rmica - 2\" width=\"352\" height=\"83\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-formula-2.png\" \/><\/a><\/p>\n<p><span>Essa \u00e9 uma f\u00f3rmula muito \u00fatil, mas aqui expressamos a efici\u00eancia t\u00e9rmica usando a primeira lei em termos de\u00a0<\/span><a title=\"O que \u00e9 entalpia\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-enthalpy\/\"><span>entalpia<\/span><\/a><span>\u00a0.<\/span><\/p>\n<figure id=\"attachment_17781\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17781\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17781 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram-300x276.png\" alt=\"Ciclo de Rankine - diagrama de Ts\" width=\"300\" height=\"276\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-Ts-diagram-300x276.png\" \/><\/a><figcaption id=\"caption-attachment-17781\" class=\"wp-caption-text\"><span>Ciclo de Rankine &#8211; diagrama de Ts<\/span><\/figcaption><\/figure>\n<p><span>Normalmente, a maioria das\u00a0<\/span><strong><span>usinas nucleares<\/span><\/strong><span>\u00a0opera\u00a0<\/span><strong><span>turbinas a vapor de condensa\u00e7\u00e3o de v\u00e1rios est\u00e1gios<\/span><\/strong><span>\u00a0.\u00a0Nessas turbinas, o est\u00e1gio de alta press\u00e3o recebe\u00a0<\/span><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0(esse vapor \u00e9 quase o vapor saturado &#8211; x = 0,995 &#8211; ponto C na figura;\u00a0<\/span><strong><span>6 MPa<\/span><\/strong><span>\u00a0; 275,6 \u00b0 C) de um gerador de vapor e o esgota no separador-reaquecedor de umidade (ponto D )\u00a0O vapor deve ser reaquecido para evitar danos que possam ser causados \u200b\u200b\u00e0s p\u00e1s da turbina a vapor por vapor de\u00a0<\/span><a title=\"Qualidade de Vapor - Fra\u00e7\u00e3o de Secura\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/vapor-quality-dryness-fraction\/\"><span>baixa qualidade<\/span><\/a><span>\u00a0.\u00a0O reaquecedor aquece o vapor (ponto D) e, em seguida, o vapor \u00e9 direcionado para o est\u00e1gio de baixa press\u00e3o da turbina a vapor, onde se expande (pontos E a F).\u00a0O vapor exaurido condensa no condensador e est\u00e1 a uma press\u00e3o bem abaixo da atmosf\u00e9rica (press\u00e3o absoluta de<\/span><strong><span>0,008 MPa<\/span><\/strong><span>\u00a0) e est\u00e1 em um estado parcialmente condensado (ponto F), tipicamente com uma qualidade pr\u00f3xima a 90%.<\/span><\/p>\n<p><span>Nesse caso, geradores de vapor, turbinas a vapor, condensadores e bombas de \u00e1gua de alimenta\u00e7\u00e3o constituem um motor t\u00e9rmico, sujeito \u00e0s limita\u00e7\u00f5es de efici\u00eancia impostas pela\u00a0<a title=\"Segunda Lei da Termodin\u00e2mica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-segunda-lei-da-termodinamica-definicao\/\"><strong>segunda lei da termodin\u00e2mica<\/strong><\/a>\u00a0.\u00a0No caso ideal (sem atrito, processos revers\u00edveis, design perfeito), este motor t\u00e9rmico teria uma\u00a0<a title=\"Efici\u00eancia de Carnot - Efici\u00eancia do mecanismo de calor de Carnot\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">efici\u00eancia<\/a>\u00a0de\u00a0<a title=\"Efici\u00eancia de Carnot - Efici\u00eancia do mecanismo de calor de Carnot\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">Carnot<\/a>\u00a0de<\/span><\/p>\n<p><span>= 1 &#8211; T\u00a0<\/span><sub><span>frio<\/span><\/sub><span>\u00a0\/ T\u00a0<\/span><sub><span>quente<\/span><\/sub><span>\u00a0= 1 &#8211; 315\/549 = 42,6%<\/span><\/p>\n<p><span>onde a temperatura do reservat\u00f3rio quente \u00e9 de 275,6 \u00b0 C (548,7 K), a temperatura do reservat\u00f3rio frio \u00e9 de 41,5 \u00b0 C (314,7 K).\u00a0Mas a usina nuclear \u00e9 o\u00a0<\/span><strong><span>verdadeiro motor t\u00e9rmico<\/span><\/strong><span>\u00a0, no qual os processos termodin\u00e2micos s\u00e3o de alguma forma irrevers\u00edveis.\u00a0Eles n\u00e3o s\u00e3o feitos infinitamente devagar.\u00a0Em dispositivos reais (como turbinas, bombas e compressores), um atrito mec\u00e2nico e perdas de calor causam mais perdas de efici\u00eancia.<\/span><\/p>\n<p><span>Para calcular a\u00a0<\/span><strong><span>efici\u00eancia t\u00e9rmica<\/span><\/strong><span>\u00a0do\u00a0<\/span><strong><span>ciclo Rankine<\/span><\/strong><span>\u00a0mais simples\u00a0(sem reaquecimento), os engenheiros usam a\u00a0<\/span><a title=\"Primeira lei em termos de entalpia dH = dQ + Vdp\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/first-law-in-terms-of-enthalpy-dh-dq-vdp\/\"><strong><span>primeira lei da termodin\u00e2mica em termos de entalpia<\/span><\/strong><\/a><span>\u00a0e n\u00e3o em energia interna.<\/span><\/p>\n<p><span>A primeira lei em termos de entalpia \u00e9:<\/span><\/p>\n<p><em><strong><span>dH = dQ + Vdp<\/span><\/strong><\/em><\/p>\n<p><span>Nesta equa\u00e7\u00e3o, o termo\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0\u00e9 um\u00a0<\/span><strong><span>trabalho de processo de fluxo.\u00a0<\/span><\/strong><span>Este trabalho, \u00a0\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0, \u00e9 usado para\u00a0<\/span><strong><span>sistemas de fluxo aberto,<\/span><\/strong><span>\u00a0como uma\u00a0<\/span><strong><span>turbina<\/span><\/strong><span>\u00a0ou uma\u00a0<\/span><strong><span>bomba<\/span><\/strong><span>\u00a0na qual existe um\u00a0<\/span><strong><span>&#8220;dp&#8221;<\/span><\/strong><span>\u00a0, ou seja, mudan\u00e7a de press\u00e3o.\u00a0N\u00e3o h\u00e1 altera\u00e7\u00f5es no\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/control-volume-control-volume-analysis\/\"><span>volume de controle<\/span><\/a><span>\u00a0.\u00a0Como pode ser visto, essa forma de lei\u00a0<\/span><strong><span>simplifica a descri\u00e7\u00e3o da transfer\u00eancia de energia<\/span><\/strong><span>\u00a0.\u00a0<\/span><strong><span>A press\u00e3o constante<\/span><\/strong><span>\u00a0, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual \u00e0\u00a0<\/span><strong><span>energia<\/span><\/strong><span>\u00a0transferida do ambiente atrav\u00e9s do aquecimento:<\/span><\/p>\n<p><strong><span>Processo isob\u00e1rico (Vdp = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = dQ \u2192 Q = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><\/p>\n<p><strong><span>Na entropia constante<\/span><\/strong><span>\u00a0, ou seja, no processo isentr\u00f3pico, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual ao\u00a0<\/span><strong><span>trabalho do processo de fluxo<\/span><\/strong><span>\u00a0realizado no ou pelo sistema:<\/span><\/p>\n<p><strong><span>Processo isentr\u00f3pico (dQ = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = Vdp \u2192 W = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><\/p>\n<p><span>\u00c9 \u00f3bvio que ser\u00e1 muito \u00fatil na an\u00e1lise de ambos os ciclos termodin\u00e2micos usados \u200b\u200bna engenharia de energia, ou seja, no ciclo de Brayton e no ciclo de Rankine.<\/span><\/p>\n<p><span>A\u00a0<\/span><strong><span>entalpia<\/span><\/strong><span>\u00a0pode ser transformada em uma\u00a0vari\u00e1vel\u00a0<\/span><strong><span>intensiva<\/span><\/strong><span>\u00a0ou\u00a0<\/span><strong><span>espec\u00edfica<\/span><\/strong><span>\u00a0dividindo-se pela\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-mass-and-weight\/what-is-mass\/\"><span>massa<\/span><\/a><span>\u00a0.\u00a0<\/span><strong><span>Os engenheiros usam mais a\u00a0<\/span><\/strong><strong><span>entalpia espec\u00edfica<\/span><\/strong><span>\u00a0na an\u00e1lise termodin\u00e2mica do que a pr\u00f3pria entalpia.\u00a0Ele \u00e9 tabulado nas\u00a0<\/span><a title=\"Tabelas de Vapor - Propriedades Espec\u00edficas da \u00c1gua e Vapor\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\"><strong><span>tabelas de vapor,<\/span><\/strong><\/a><span>\u00a0juntamente com o\u00a0<\/span><a title=\"O que \u00e9 volume espec\u00edfico\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-specific-volume\/\"><span>volume\u00a0<\/span><\/a><a title=\"Energia interna espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/specific-internal-energy\/\"><span>espec\u00edfico<\/span><\/a><span>\u00a0e\u00a0<a title=\"Energia interna espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/specific-internal-energy\/\">a energia interna espec\u00edfica<\/a>\u00a0.\u00a0A efici\u00eancia t\u00e9rmica desse ciclo simples de Rankine e em termos de entalpias espec\u00edficas seria:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-16962 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\" alt=\"efici\u00eancia t\u00e9rmica do ciclo Rankine\" width=\"535\" height=\"68\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\" \/><\/a><\/p>\n<p><span>\u00c9 uma equa\u00e7\u00e3o muito simples e, para determinar a efici\u00eancia t\u00e9rmica, voc\u00ea pode usar os dados das\u00a0<\/span><strong><span>tabelas de vapor<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<figure id=\"attachment_16961\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16961\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min.png\"><img loading=\"lazy\" class=\"wp-image-16961 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min.png\" alt=\"Takaishi, Tatsuo;  Numata, Akira;  Nakano, Ryouji;  Sakaguchi, Katsuhiko (mar\u00e7o de 2008).\" width=\"452\" height=\"334\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min.png\" \/><\/a><figcaption id=\"caption-attachment-16961\" class=\"wp-caption-text\"><span>Takaishi, Tatsuo;\u00a0Numata, Akira;\u00a0Nakano, Ryouji;\u00a0Sakaguchi, Katsuhiko (mar\u00e7o de 2008).\u00a0\u201cAbordagem para motores a diesel e g\u00e1s de alta efici\u00eancia\u201d (PDF).\u00a0Revis\u00e3o t\u00e9cnica Mitsubishi Heavy Industries.\u00a045 (1).\u00a0P\u00e1gina visitada em 2011-02-04.<\/span><\/figcaption><\/figure>\n<p><span>Nas modernas usinas nucleares, a efici\u00eancia t\u00e9rmica geral \u00e9 de cerca de\u00a0<\/span><strong><span>um ter\u00e7o<\/span><\/strong><span>\u00a0(33%), de modo que s\u00e3o necess\u00e1rios\u00a0<\/span><strong><span>3000 MWth<\/span><\/strong><span>\u00a0de energia t\u00e9rmica da rea\u00e7\u00e3o de fiss\u00e3o para gerar\u00a0<\/span><strong><span>1000 MWe<\/span><\/strong><span>\u00a0de energia el\u00e9trica.\u00a0O motivo est\u00e1 na temperatura do vapor relativamente baixa (\u00a0<\/span><strong><span>6 MPa<\/span><\/strong><span>\u00a0; 275,6 \u00b0 C).\u00a0Efici\u00eancias mais altas podem ser alcan\u00e7adas aumentando a\u00a0<\/span><strong><span>temperatura<\/span><\/strong><span>do vapor.\u00a0Mas isso requer um aumento nas press\u00f5es dentro de caldeiras ou geradores de vapor.\u00a0No entanto, considera\u00e7\u00f5es metal\u00fargicas imp\u00f5em limites superiores a essas press\u00f5es.\u00a0Em compara\u00e7\u00e3o com outras fontes de energia, a efici\u00eancia t\u00e9rmica de 33% n\u00e3o \u00e9 grande.\u00a0Mas deve-se notar que as usinas nucleares s\u00e3o muito mais complexas que as usinas de combust\u00edveis f\u00f3sseis e \u00e9 muito mais f\u00e1cil queimar combust\u00edveis f\u00f3sseis do que gerar energia a partir de combust\u00edveis nucleares.\u00a0As usinas subcr\u00edticas de combust\u00edveis f\u00f3sseis, que s\u00e3o operadas sob\u00a0<\/span><a title=\"Press\u00e3o cr\u00edtica da \u00e1gua\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-pressure-physics\/critical-pressure-of-water\/\"><strong><span>press\u00e3o cr\u00edtica<\/span><\/strong>\u00a0<\/a><span>(ou seja, inferiores a 22,1 MPa), podem atingir uma efici\u00eancia de 36 a 40%.<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Causas de inefici\u00eancia<\/span><\/h2>\n<p><span>Como foi discutido, uma efici\u00eancia pode variar entre 0 e 1. Cada mecanismo t\u00e9rmico \u00e9 de alguma forma ineficiente.\u00a0Essa inefici\u00eancia pode ser atribu\u00edda a tr\u00eas causas.<\/span><\/p>\n<ul>\n<li><strong><span>Irreversibilidade de processos<\/span><\/strong><span>\u00a0.\u00a0Existe um limite superior te\u00f3rico geral para a efici\u00eancia da convers\u00e3o de calor em trabalho em qualquer motor t\u00e9rmico.\u00a0Esse limite superior \u00e9 chamado de\u00a0<\/span><strong><span>efici\u00eancia de Carnot<\/span><\/strong><span>\u00a0.\u00a0De acordo com o\u00a0<\/span><strong><span>princ\u00edpio Carnot<\/span><\/strong><span>\u00a0, nenhum motor pode ser mais eficiente que um motor revers\u00edvel (\u00a0<\/span><strong><span>um motor t\u00e9rmico Carnot<\/span><\/strong><span>\u00a0) operando entre os mesmos reservat\u00f3rios de alta e baixa temperatura.\u00a0Por exemplo, quando o reservat\u00f3rio quente tem T\u00a0<\/span><sub><span>quente<\/span><\/sub><span>\u00a0de 400 \u00b0 C (673K) e T\u00a0<\/span><sub><span>frio<\/span><\/sub><span>\u00a0de cerca de 20 \u00b0 C (293K), a efici\u00eancia m\u00e1xima (ideal) ser\u00e1: = 1 &#8211; T\u00a0<\/span><sub><span>frio<\/span><\/sub><span>\u00a0\/ T\u00a0<\/span><sub><span>quente<\/span><\/sub><span>\u00a0= 1 &#8211; 293 \/ 673 = 56%.\u00a0Mas todos os processos termodin\u00e2micos reais s\u00e3o de alguma forma\u00a0<\/span><strong><span>irrevers\u00edveis<\/span><\/strong><span>.\u00a0Eles n\u00e3o s\u00e3o feitos infinitamente devagar.\u00a0Portanto, os motores t\u00e9rmicos devem ter efici\u00eancias mais baixas do que os limites de efici\u00eancia devido \u00e0 irreversibilidade inerente ao ciclo dos motores t\u00e9rmicos que utilizam.<\/span><\/li>\n<li><strong><span>Presen\u00e7a de fric\u00e7\u00e3o e perdas de calor.\u00a0<\/span><\/strong><span>Em sistemas termodin\u00e2micos reais ou em motores t\u00e9rmicos reais, parte da inefici\u00eancia geral do ciclo \u00e9 devida \u00e0s perdas dos componentes individuais.\u00a0Em dispositivos reais (como turbinas, bombas e compressores), um\u00a0<\/span><strong><span>atrito mec\u00e2nico<\/span><\/strong><span>\u00a0,\u00a0<\/span><strong><span>perdas de calor<\/span><\/strong><span>\u00a0e perdas no processo de combust\u00e3o causam mais perdas de efici\u00eancia.<\/span><\/li>\n<li><strong><span>Inefici\u00eancia do projeto<\/span><\/strong><span>\u00a0.\u00a0Finalmente, a \u00faltima e tamb\u00e9m importante fonte de inefici\u00eancias prov\u00e9m dos\u00a0<\/span><strong><span>compromissos<\/span><\/strong><span>\u00a0assumidos pelos\u00a0<\/span><strong><span>engenheiros<\/span><\/strong><span>\u00a0ao projetar um motor t\u00e9rmico (por exemplo, usina).\u00a0Eles devem considerar o custo e outros fatores no design e opera\u00e7\u00e3o do ciclo.\u00a0Como exemplo, considere um projeto do\u00a0<\/span><strong><span>condensador<\/span><\/strong><span>\u00a0nas usinas termel\u00e9tricas.\u00a0Idealmente, o vapor descarregado no condensador n\u00e3o teria\u00a0<\/span><strong><span>sub-resfriamento<\/span><\/strong><span>\u00a0.\u00a0Mas os condensadores reais s\u00e3o projetados para sub-resfriar o l\u00edquido em alguns graus Celsius, a fim de evitar a\u00a0<\/span><a title=\"Cavita\u00e7\u00e3o por suc\u00e7\u00e3o\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/centrifugal-pumps\/cavitation\/suction-cavitation\/\"><strong><span>cavita\u00e7\u00e3o de suc\u00e7\u00e3o<\/span><\/strong><\/a><span>\u00a0nas bombas de condensado.\u00a0Por\u00e9m, esse sub-resfriamento aumenta a inefici\u00eancia do ciclo, porque \u00e9 necess\u00e1ria mais energia para reaquecer a \u00e1gua.<\/span><\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Melhoria da efici\u00eancia t\u00e9rmica &#8211; ciclo Rankine<\/span><\/h2>\n<p><span>Existem v\u00e1rios m\u00e9todos, como pode ser melhorada a efici\u00eancia t\u00e9rmica do ciclo Rankine.\u00a0Assumindo que a temperatura m\u00e1xima seja limitada pela press\u00e3o dentro do vaso de press\u00e3o do reator, esses m\u00e9todos s\u00e3o:<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-60 lgc-tablet-grid-60 lgc-mobile-grid-100 lgc-equal-heights  lgc-first\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Efici\u00eancia isentr\u00f3pica &#8211; turbina, bomba<\/span><\/h2>\n<p><span>Nos cap\u00edtulos anteriores assumiu-se que a expans\u00e3o do vapor \u00e9 isentr\u00f3pica e, portanto, utilizou-se o t\u00a0<\/span><sub><span>4, \u00e9<\/span><\/sub><span>\u00a0\u00a0como a temperatura de sa\u00edda do g\u00e1s.\u00a0Essas premissas s\u00e3o aplic\u00e1veis \u200b\u200bapenas aos ciclos ideais.<\/span><\/p>\n<p><span>A maioria dos dispositivos de fluxo constante (turbinas, compressores, bicos) opera em condi\u00e7\u00f5es adiab\u00e1ticas, mas n\u00e3o s\u00e3o verdadeiramente isentr\u00f3picos, mas s\u00e3o idealizados como isentr\u00f3picos para fins de c\u00e1lculo.\u00a0Definimos os par\u00e2metros\u00a0<\/span><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0,\u00a0<\/span><\/em><\/strong>\u00a0<strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>P<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0, \u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>N<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0,<\/span><\/em><\/strong><span>\u00a0como uma raz\u00e3o entre o trabalho real realizado pelo dispositivo e o trabalho por dispositivo quando operado em condi\u00e7\u00f5es isentr\u00f3picas (no caso de turbinas).\u00a0Essa rela\u00e7\u00e3o \u00e9 conhecida como\u00a0<\/span><a title=\"Efici\u00eancia isentr\u00f3pica - Turbina \/ Compressor \/ Bocal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-processes\/isentropic-process\/isentropic-efficiency-turbinecompressornozzle\/\"><strong><span>Efici\u00eancia de turbina isentr\u00f3pica \/ bomba \/ bico<\/span><\/strong><\/a><span>\u00a0.\u00a0Esses par\u00e2metros descrevem com que efici\u00eancia uma turbina, compressor ou bico se aproxima de um dispositivo isentr\u00f3pico correspondente.\u00a0Este par\u00e2metro reduz a efici\u00eancia geral e a produ\u00e7\u00e3o do trabalho.\u00a0Para turbinas, o valor de\u00a0<\/span><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T<\/span><\/sub><\/em><\/strong><span>\u00a0\u00e9 tipicamente de 0,7 a 0,9 (70-90%).<\/span><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"Processo isentr\u00f3pico\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-processo-isentropico-definicao\/\"><span>Processo isentr\u00f3pico<\/span><\/a><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-turbine-pump.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17790 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-turbine-pump.png\" alt=\"Efici\u00eancia isentr\u00f3pica - turbina - bomba\" width=\"567\" height=\"365\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-turbine-pump.png\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-40 lgc-tablet-grid-40 lgc-mobile-grid-100 lgc-equal-heights  lgc-last\">\n<div class=\"inside-grid-column\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression.png\"><img loading=\"lazy\" class=\"aligncenter size-medium wp-image-17268 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression-274x300.png\" alt=\"Compress\u00e3o isentr\u00f3pica vs. adiab\u00e1tica\" width=\"274\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression-274x300.png\" \/><\/a><\/p>\n<figure id=\"attachment_17267\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-17267\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17267 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" alt=\"Expans\u00e3o isentr\u00f3pica vs. adiab\u00e1tica\" width=\"276\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" \/><\/a><figcaption id=\"caption-attachment-17267\" class=\"wp-caption-text\"><span>O processo isentr\u00f3pico \u00e9 um caso especial de processos adiab\u00e1ticos.\u00a0\u00c9 um processo adiab\u00e1tico revers\u00edvel.\u00a0Um processo isentr\u00f3pico tamb\u00e9m pode ser chamado de processo de entropia constante.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Ciclo de Rankine &#8211; Problema com Solu\u00e7\u00e3o<\/span><\/h2>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\"><img loading=\"lazy\" class=\"alignright size-full wp-image-17771 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\" alt=\"Ciclo Rankine\" width=\"300\" height=\"450\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-Cycle-scheme.png\" \/><\/a><span>Vamos assumir o\u00a0<\/span><strong><span>ciclo Rankine<\/span><\/strong><span>\u00a0, que \u00e9 um dos\u00a0<\/span><strong><span>ciclos termodin\u00e2micos<\/span><\/strong><span>\u00a0mais comuns\u00a0em usinas termel\u00e9tricas.\u00a0Nesse caso, assuma um ciclo simples, sem reaquecimento e sem a turbina a vapor de condensa\u00e7\u00e3o funcionando com\u00a0<\/span><a title=\"Vapor seco\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/dry-steam\/\"><span>vapor saturado<\/span><\/a><span>\u00a0\u00a0(vapor seco).\u00a0Nesse caso, a turbina opera em estado estacion\u00e1rio com condi\u00e7\u00f5es de entrada de 6 MPa, t = 275,6 \u00b0 C, x = 1 (ponto 3).\u00a0O vapor sai deste est\u00e1gio da turbina a uma press\u00e3o de 0,008 MPa, 41,5 \u00b0 C e x = ???\u00a0(ponto 4)<\/span><\/p>\n<p><span>Calcular:<\/span><\/p>\n<ol>\n<li><span>a qualidade do vapor do vapor de sa\u00edda<\/span><\/li>\n<li><span>a diferen\u00e7a de entalpia entre estes dois estados (3 \u2192 4), a qual corresponde ao trabalho realizado pelo vapor, W\u00a0<\/span><sub><span>t<\/span><\/sub><span>\u00a0.<\/span><\/li>\n<li><span>a diferen\u00e7a de entalpia entre estes dois estados (1 \u2192 2), que corresponde ao trabalho feito por bombas, W\u00a0<\/span><sub><span>P<\/span><\/sub><span>\u00a0.<\/span><\/li>\n<li><span>a diferen\u00e7a de entalpia entre esses dois estados (2 \u2192 3), que corresponde ao calor l\u00edquido adicionado no gerador de vapor<\/span><\/li>\n<li><span>a efici\u00eancia termodin\u00e2mica deste ciclo e compare esse valor com a efici\u00eancia de Carnot<\/span><\/li>\n<\/ol>\n<p><span>1)<\/span><\/p>\n<p><span>Como n\u00e3o sabemos a qualidade exata do vapor de sa\u00edda, precisamos determinar esse par\u00e2metro.\u00a0O estado 4 \u00e9 fixado pela press\u00e3o\u00a0<\/span><strong><span>p\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0= 0,008 MPa<\/span><\/strong><span>\u00a0e o fato de que a\u00a0<\/span><a title=\"Entropia espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-entropy\/specific-entropy\/\"><span>entropia espec\u00edfica<\/span><\/a><span>\u00a0\u00e9 constante para a expans\u00e3o isentr\u00f3pica (s\u00a0<\/span><sub><span>3<\/span><\/sub><span>\u00a0= s\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0= 5,89\u00a0<\/span><em><span>kJ \/ kgK para 6 MPa<\/span><\/em><span>\u00a0).\u00a0A entropia espec\u00edfica da \u00e1gua l\u00edquida saturada (x = 0) e do vapor seco (x = 1) pode ser selecionada nas\u00a0<\/span><a title=\"Tabelas de Vapor - Propriedades Espec\u00edficas da \u00c1gua e Vapor\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\"><span>tabelas de vapor<\/span><\/a><span>\u00a0.\u00a0No caso de vapor \u00famido, a entropia real pode ser calculada com a qualidade do vapor,\u00a0<\/span><em><span>x,<\/span><\/em><span>\u00a0e as entropias espec\u00edficas de \u00e1gua l\u00edquida saturada e vapor seco:<\/span><\/p>\n<p><em><span>s\u00a0<\/span><\/em><em><sub><span>4<\/span><\/sub><\/em><em><span>\u00a0= s\u00a0<\/span><\/em><em><sub><span>v<\/span><\/sub><\/em><em><span>\u00a0x + (1 &#8211; x) s\u00a0<\/span><\/em><em><sub><span>l<\/span><\/sub><\/em><em>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/em><\/p>\n<p><em><span>Onde<\/span><\/em><\/p>\n<p><em><span>s\u00a0<\/span><\/em><em><sub><span>4<\/span><\/sub><\/em><em><span>\u00a0= entropia de vapor \u00famido (J \/ kg K) =<\/span><\/em><span>\u00a05,89\u00a0<\/span><em><span>kJ \/ kgK<\/span><\/em><\/p>\n<p><em><span>s\u00a0<\/span><\/em><em><sub><span>v<\/span><\/sub><\/em><em><span>\u00a0= entropia do vapor &#8220;seco&#8221; (J \/ kg K) = 8,227 kJ \/ kgK (para 0,008 MPa)<\/span><\/em><\/p>\n<p><em><span>s\u00a0<\/span><\/em><em><sub><span>l<\/span><\/sub><\/em><em><span>\u00a0= entropia de \u00e1gua l\u00edquida saturada (J \/ kg K) = 0,592 kJ \/ kgK (para 0,008 MPa)<\/span><\/em><\/p>\n<p><span>A partir desta equa\u00e7\u00e3o, a qualidade do vapor \u00e9:<\/span><\/p>\n<p><span>x\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0= (\u00a0<\/span><em><span>s\u00a0<\/span><\/em><em><sub><span>4<\/span><\/sub><\/em><em><span>\u00a0&#8211; s\u00a0<\/span><\/em><em><sub><span>l<\/span><\/sub><\/em><span>\u00a0) \/ (\u00a0<\/span><em><span>s\u00a0<\/span><\/em><em><sub><span>v<\/span><\/sub><\/em><em><span>\u00a0&#8211; s\u00a0<\/span><\/em><em><sub><span>l<\/span><\/sub><\/em><span>\u00a0) = (5,89 &#8211; 0,592) \/ (8,227 &#8211; 0,592) = 0,694 = 69,4%<\/span><\/p>\n<p><span>2)<\/span><\/p>\n<p><span>A entalpia para o estado 3 pode ser coletada diretamente das tabelas de vapor, enquanto a entalpia para o estado 4 deve ser calculada usando a qualidade do vapor:<\/span><\/p>\n<p><em><span>h\u00a0<\/span><\/em><em><sub><span>3, v<\/span><\/sub><\/em><em><span>\u00a0=<\/span><\/em><span>\u00a02785 kJ \/ kg<\/span><\/p>\n<p><em><span>h\u00a0<\/span><\/em><em><sub><span>4, molhado<\/span><\/sub><\/em><em><span>\u00a0= h\u00a0<\/span><\/em><em><sub><span>4, v<\/span><\/sub><\/em><em><span>\u00a0x + (1 &#8211; x) h\u00a0<\/span><\/em><em><sub><span>4, l<\/span><\/sub><\/em><span>\u00a0\u00a0= 2576.\u00a00,694 + (1 &#8211; 0,694).\u00a0174 = 1787 + 53,2 = 1840 kJ \/ kg<\/span><\/p>\n<p><span>Ent\u00e3o o trabalho realizado pelo vapor, W\u00a0<\/span><sub><span>T,<\/span><\/sub><span>\u00a0\u00e9<\/span><\/p>\n<p><strong><span>W\u00a0<\/span><\/strong><strong><sub><span>T<\/span><\/sub><\/strong><span>\u00a0= \u0394h =\u00a0<\/span><strong><span>945 kJ \/ kg<\/span><\/strong><\/p>\n<p><strong><span>3)<\/span><\/strong><\/p>\n<p><span>A entalpia para o estado 1 pode ser obtida diretamente das tabelas de vapor:<\/span><\/p>\n<p><em><span>h\u00a0<\/span><\/em><em><sub><span>1, l<\/span><\/sub><\/em><em><span>\u00a0=<\/span><\/em><span>\u00a0174 kJ \/ kg<\/span><\/p>\n<p><span>O estado 2 \u00e9 fixado pela press\u00e3o p\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0= 6,0 MPa e pelo fato de a entropia espec\u00edfica ser constante para a compress\u00e3o isentr\u00f3pica (s\u00a0<\/span><sub><span>1<\/span><\/sub><span>\u00a0= s\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0= 0,592\u00a0<\/span><em><span>kJ \/ kgK para 0,008 MPa<\/span><\/em><span>\u00a0).\u00a0Para esta entropia s\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0=\u00a0<\/span><strong><span>0,592\u00a0<\/span><em><span>kJ \/ kgK<\/span><\/em><\/strong><span>\u00a0ep\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0= 6,0 MPa, encontramos\u00a0<\/span><strong><em><span>h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2, sub-resfriado<\/span><\/sub><\/em><\/strong><span>\u00a0em tabelas de vapor para \u00e1gua comprimida (usando interpola\u00e7\u00e3o entre dois estados).<\/span><\/p>\n<p><strong><em><span>h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2, sub-resfriado<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0=<\/span><\/em><\/strong><strong><span>\u00a0179,7 kJ \/ kg<\/span><\/strong><\/p>\n<p><span>Ent\u00e3o, o trabalho realizado pelas bombas, W\u00a0<\/span><sub><span>P,<\/span><\/sub><span>\u00a0\u00e9<\/span><\/p>\n<p><strong><span>W\u00a0<\/span><\/strong><strong><sub><span>P<\/span><\/sub><\/strong><span>\u00a0= \u0394h =\u00a0<\/span><strong><span>5,7 kJ \/ kg<\/span><\/strong><\/p>\n<p><span>4)<\/span><\/p>\n<p><span>A diferen\u00e7a de entalpia entre (2 \u2192 3), que corresponde ao calor l\u00edquido adicionado no gerador de vapor, \u00e9 simplesmente:<\/span><\/p>\n<p><strong><em><span>Q\u00a0<\/span><\/em><\/strong><strong><em><sub><span>add<\/span><\/sub><\/em><\/strong><em><span>\u00a0= h\u00a0<\/span><\/em><em><sub><span>3, v<\/span><\/sub><\/em><em><span>\u00a0\u00a0&#8211; h\u00a0<\/span><\/em><em><sub><span>2, sub-resfriado<\/span><\/sub><\/em><em><span>\u00a0= 2785 &#8211; 179,7 = \u00a0\u00a0<\/span><strong><span>2605,3 kJ \/ kg<\/span><\/strong><\/em><\/p>\n<p><span>Observe que, n\u00e3o h\u00e1 regenera\u00e7\u00e3o de calor neste ciclo.\u00a0Por outro lado, a maior parte do calor adicionado \u00e9 para a entalpia da vaporiza\u00e7\u00e3o (isto \u00e9, para a mudan\u00e7a de fase).<\/span><\/p>\n<p><span>5)<\/span><\/p>\n<p><span>Nesse caso, geradores de vapor, turbinas a vapor, condensadores e bombas de \u00e1gua de alimenta\u00e7\u00e3o constituem um motor t\u00e9rmico, sujeito \u00e0s limita\u00e7\u00f5es de efici\u00eancia impostas pela\u00a0<a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-segunda-lei-da-termodinamica-definicao\/\"><strong>segunda lei da termodin\u00e2mica<\/strong><\/a>\u00a0.\u00a0No caso ideal (sem atrito, processos revers\u00edveis, design perfeito), este motor t\u00e9rmico teria uma\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">efici\u00eancia<\/a>\u00a0de\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">Carnot<\/a>\u00a0de<\/span><\/p>\n<p><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>Carnot<\/span><\/sub><\/em><\/strong><span>\u00a0= 1 &#8211; T<\/span><sub><span>\u00a0frio<\/span><\/sub><span>\u00a0\/ T<\/span><sub><span>\u00a0quente<\/span><\/sub><span>\u00a0= 1 &#8211; 315\/549 =<\/span><strong><span>\u00a042,6%<\/span><\/strong><\/p>\n<p><span>onde a temperatura do reservat\u00f3rio quente \u00e9 de 275,6 \u00b0 C (548,7 K), a temperatura do reservat\u00f3rio frio \u00e9 de 41,5 \u00b0 C (314,7 K).<\/span><\/p>\n<p><span>A efici\u00eancia termodin\u00e2mica deste ciclo pode ser calculada pela seguinte f\u00f3rmula:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-cycle-example-thermal-efficiency.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17792 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-cycle-example-thermal-efficiency.png\" alt=\"Ciclo de Rankine - exemplo - efici\u00eancia t\u00e9rmica\" width=\"159\" height=\"76\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Rankine-cycle-example-thermal-efficiency.png\" \/><\/a><\/p>\n<p><span>assim<\/span><br \/>\n<strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>th<\/span><\/sub><\/em><\/strong><span>\u00a0= (945 &#8211; 5,7) \/ 2605,3 = 0,361 =\u00a0<\/span><strong><span>36,1%<\/span><\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div><\/div>\n<div>\n<p>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.<\/p>\n<p>Este artigo \u00e9 baseado na tradu\u00e7\u00e3o autom\u00e1tica do artigo original em ingl\u00eas. Para mais informa\u00e7\u00f5es, consulte o artigo em ingl\u00eas. Voc\u00ea pode nos ajudar. Se voc\u00ea deseja corrigir a tradu\u00e7\u00e3o, envie-a para: translations@nuclear-power.com ou preencha o formul\u00e1rio de tradu\u00e7\u00e3o on-line. Agradecemos sua ajuda, atualizaremos a tradu\u00e7\u00e3o o mais r\u00e1pido poss\u00edvel. Obrigado.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>O principal dispositivo do sistema de convers\u00e3o de energia \u00e9 o gerador de turbina. O gerador de turbina est\u00e1 no pr\u00e9dio da turbina e cont\u00e9m a maioria dos principais componentes do ciclo termodin\u00e2mico. Engenharia T\u00e9rmica Gerador de turbina &#8211; Sistema de convers\u00e3o de energia A disposi\u00e7\u00e3o de\u00a0centrais de energia nuclear\u00a0compreende duas partes principais:\u00a0A\u00a0ilha nuclear\u00a0e a\u00a0ilha &#8230; <a title=\"O que \u00e9 gerador de turbina &#8211; Sistema de convers\u00e3o de energia &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-gerador-de-turbina-sistema-de-conversao-de-energia-definicao\/\" aria-label=\"More on O que \u00e9 gerador de turbina &#8211; Sistema de convers\u00e3o de energia &#8211; Defini\u00e7\u00e3o\">Ler mais<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[14],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>O que \u00e9 gerador de turbina - Sistema de convers\u00e3o de energia - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"O principal dispositivo do sistema de convers\u00e3o de energia \u00e9 o gerador de turbina. 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