集成捕碳系统的二次再热机组优化研究

发布时间：2018-04-21 09:18

本文选题：二次再热机组 + 碳捕集　；参考：《华北电力大学》2017年硕士论文

【摘要】：对传统燃煤机组进行捕碳改造,可以明显降低机组CO_2排放率,但是由于捕碳系统会抽取大量蒸汽,导致改造后机组偏离最佳运行工况,严重降低机组热经济性。如何使机组在捕碳的同时具有较高的热经济性,是目前一个亟待解决的问题。本文以某660MW二次再热机组为参考机组,对机组与捕碳系统的优化集成展开深入研究。使用机组热力系统抽汽,为采用单乙醇胺(MEA)作为吸收剂的化学吸收法的捕碳系统提供能量。提出捕碳系统与机组集成的常规改造方案,构建改造方案下的机组热力系统,对机组循环热效率进行计算。针对改造方案存在的不足,提出了一种引入捕碳汽轮机的改进设计集成方案,对改进设计方案的汽水分布方程和机组循环热效率计算式进行推导,并引入动态自适应粒子群优化算法,对改进设计方案的系统参数进行优化计算。通过对比,发现100%负荷及75%负荷下改进设计机组热经济性及减排效果均明显好于常规改造机组。100%负荷下改进设计机组比常规改造机组发电标准煤耗率降低了10.32g/(kW·h),CO_2排放率降低了4.07g/(kW·h)。对抽汽过热度及火用损失进行了对比分析后发现,捕碳汽轮机的引入可以有效减少热力系统火用损失,对改进设计机组有明显的降耗效应。将间接发生蒸汽的槽式太阳能集热系统引入二次再热燃煤-捕碳机组。提出太阳能与捕碳系统集成及太阳能与回热系统集成这两种集成方案以及每种方案的可选系统结构,推导通用汽水分布方程。对不同方案进行分析评价,找到太阳能集热系统与二次再热燃煤-捕碳系统集成的最佳方案。通过对比,发现太阳能为改进设计方案的1号高压加热器供能时机组热经济性和技术经济性均为最优,是最佳集成方案。该方案可使改进设计机组发电标准煤耗率降低21.89g/(kW·h),CO_2排放率降低8.64g/(kW·h)。
[Abstract]:The carbon capture transformation of traditional coal-fired units can obviously reduce the CO_2 emission rate of the units, but the carbon capture system will extract a large amount of steam, which leads to the deviation of the units from the optimal operating conditions and seriously reduces the thermal economy of the units. How to make the unit carbon capture at the same time has a higher thermal economy, is a problem to be solved. In this paper, a 660MW secondary reheat unit is used as a reference unit, and the optimization integration between the unit and the carbon capture system is studied in depth. The extraction of steam from unit thermodynamic system provides energy for carbon capture system using monoethanolamine (MEA) as absorbent. The conventional retrofit scheme of carbon capture system and unit integration is put forward, and the unit thermal system under the transformation scheme is constructed, and the cycle heat efficiency of the unit is calculated. In view of the shortcomings of the retrofit scheme, an improved design integration scheme with carbon capture steam turbine is put forward. The steam water distribution equation of the improved design scheme and the calculation formula of unit cycle heat efficiency are derived. The dynamic adaptive particle swarm optimization algorithm is introduced to optimize the system parameters of the improved design scheme. By comparison, it is found that the thermal economy and emission reduction effect of the improved design unit under 100% and 75% load are obviously better than that of the conventional retrofit unit under .100% load. Compared with the conventional retrofit unit, the standard coal consumption rate of the improved design unit is lower than that of the conventional retrofit unit, and the emission rate of 10.32g/(kW / CO _ 2 decreases the 4.07g/(kW _ hh _ 2 emission rate. It is found that the introduction of carbon capture steam turbine can effectively reduce the exergy loss of thermal system and has obvious effect on reducing the consumption of improved design units by comparing and analyzing the overheating degree and exergy loss of extraction steam turbine. The trough solar energy collector system with indirect steam generation is introduced into the secondary reheat coal-carbon-capture unit. Two integrated schemes of solar energy and carbon capture system and solar energy and heat recovery system are presented, and the alternative system structure of each scheme is presented. The general distribution equation of steam and water is derived. Different schemes were analyzed and evaluated to find the best scheme for the integration of solar energy collection system and secondary reheat coal-carbon capture system. Through comparison, it is found that the thermal economy and technical economy of the No. 1 high-pressure heater with solar energy as the improved design scheme are the best and the best integration scheme. The scheme can reduce the standard coal consumption rate of the improved design unit and reduce the emission rate of 21.89g/(kW hu / CO _ 2 and reduce the 8.64g/(kW hu ~ (2) emission rate.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621

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