电厂汽轮机组的脱碳热耦合变工况模拟及汽耗特性

Off-design simulation of decarbonized thermal coupling and steam consumption characteristics of turbine unit in power plant

燃煤电厂采用醇胺法碳捕集会降低电厂汽轮机组的发电功率及发电效率,也会使汽轮机组汽耗特性曲线与设计曲线相比发生变化,因此需要变工况模拟脱碳热耦合对汽轮机组性能的影响,并重新绘制脱碳汽轮机组的汽耗特性曲线。文中采用模拟准确度更高的变流量变压力方法,模拟了脱碳热耦合对锦界电厂汽轮机组的影响,并将模拟结果与目前研究中常用的变流量定压力方法模拟结果进行对比分析。在此基础上,针对目前缺乏相关脱碳汽轮机组汽耗特性关系研究的问题,提出采用变流量变压力方法研究脱碳汽轮机组的汽耗特性关系,绘制汽耗特性曲线,为脱碳汽轮机组的运行调节提供依据,填补相关研究空白。模拟结果表明,当二氧化碳捕集规模为15万t/a时,变流量变压力模拟得到的脱碳汽轮机组发电功率与变流量定压力模拟结果相比高22 kW,相差0.04%,2种模拟方法的模拟结果相差不大;当锦界电厂600 MW机组的锅炉烟气CO_(2)全部捕集(捕集规模为360万t/a),变流量变压力模拟得到的脱碳汽轮机组发电功率与变流量定压力模拟结果相比高33.7 MW,相差5.61%。汽耗特性研究结果表明,随碳捕集规模增加,脱碳热耦合机组发电功率减小,机组汽耗特性变动率逐渐增大。当碳捕集规模分别为烟气CO_(2)捕集率为4%(年捕集量15万t)、捕集率60%、捕集率80%以及烟气CO_(2)全部捕集时,脱碳汽轮机组的汽耗特性曲线变动最大值分别为1.3%、11.85%、12.6%及13.2%。

Coal-fired power plant integrated with the carbon capture by alcoholamine method not only can reduce the power generation and power generation efficiency of unit,but also can change the steam consumption characteristics curve of the unit.Therefore,it is significant to explore the effects of the thermal coupling of carbon capture system on the decarbonized turbine unit performance by off-design simulation,as well as to redraw the steam consumption characteristics curve of the decarbonized turbine unit.In this paper,a more accurate variable flow and pressure method,which takes into account both flow and pressure variation,was adopted to simulate the effects of decarbonized thermal coupling on the turbine unit in Jinjie power plant.The simulation results were compared with those of the variable flow and constant pressure method commonly used in current research.With the analysis results,the steam consumption characteristics of the decarbonized turbine unit were researched by the variable flow and pressure method to address the lack of research on the steam consumption characteristics of the decarbonized turbine unit,and the steam consumption characteristics curve was drawn to control the operating parameters.The simulation results show that,with 150000 t/a capture scale,the power generation of decarbonized turbine unit simulated by variable flow and pressure method is 22 kW higher than variable flow and constant pressure method,with a difference of 0.04%,meaning the difference between of the simulation results by two methods is not significant.When the CO_(2)in the flue gas from Jinjie power plant is captured in full(with 3600000 t/a capture scale),the power generation of decarbonized turbine unit simulated by variable flow and pressure method is 33.7 MW higher than variable flow and constant pressure method,with a difference of 5.61%.The simulation results of steam consumption characteristics of decarbonized turbine unit show that a higher capture scale leads to a lower power generation,which results a bigger variation of steam consumption characteristics of decarbonized unit.With the carbon capture rate are 4%(150000 t/a capture scale),60%,80%and 100%,the maximum variation of steam characteristics curves of decarbonized turbine unit are 1.3%,11.85%,12.6%,13.2%respectively.