【作者】 李停停；

【导师】 刘炳成；

【作者基本信息】 青岛科技大学 ， 制冷及低温工程， 2010， 硕士

【摘要】 温室气体的过量排放将会造成全球范围内的气温变化,CO₂的排放控制及回收技术已经是当前的一项重要工作。目前的回收技术对整个系统的能耗情况、节点的相互影响、能量利用的薄弱环节还缺乏整体把握。本文在现有回收技术的基础上,改进现有的脱除工艺,分析各影响因素对脱除率的影响,进行综合的能耗分析及热经济性分析。本文以燃煤电厂烟气为对象,根据燃煤厂烟气中二氧化碳的特点,选择MEA化学吸收法进行捕集纯化,对MEA化学吸收法进行了机理分析,探讨了MEA化学吸收法的优缺点。基于PRO/II软件的AMSIM模块,建立了MEA化学吸收法工艺系统的流程分析模型,分析了吸收温度、吸收剂流量、吸收剂浓度及解吸温度对脱除率、热负荷、再生率等的影响。分析表明:吸收温度越高,脱除率越高,但吸收温度不是越高越好,30⁴0℃是常规系统适宜的温度;吸收剂流量越大,脱除率越高,但是吸收剂流量选择要适宜,常规系统适宜的吸收剂流量为80¹20 m3/h;吸收剂浓度越高,脱除率越高,但是吸收剂浓度选择要适宜,常规系统适宜选用吸收剂浓度为15%²0%;解吸温度升高,富液的解吸率随着升高,解吸温度宜取100℃¹20℃。以热力学第一定律和第二定律为理论基础,确定了捕集系统的能分析方法,建立了捕集系统能分析模型,利用黑箱模型对捕集系统进行了热负荷计算,能量衡算及可用能分析,分析表明:分离过程可用能效率只有12.8%。根据火用分析方法建立了捕集系统的火用分析模型,利用黑箱模型对捕集系统及子系统进行了火用分析和火用损耗分析,分析表明:再沸器的火用效率最低,吸收塔的火用损耗很大,有很大的节能潜力。对系统再生能耗进行了分析,分析表明:提高吸收液浓度可以降低再生能耗,但吸收液质量浓度必定会存在一个极限值φmax;提高富液的再生度ξ,能降低再生能耗qs tr,但ξ不是越高越好;改善贫富液热交换器的换热性能可以降低总再生能耗。以热经济学基本思想为基础,确定了适合于捕集系统的热经济学分析方法,建立了捕集系统热经济学分析模型和火用成本方程,确定了优化目标函数,并对捕集系统进行了热经济学分析,分析表明:回收CO₂大概需要的成本为582元/t。探讨了捕集系统的节能降耗方案,为化学吸收法二氧化碳捕集系统的节能优化技术奠定了理论基础和经济基础。更多还原

【Abstract】 The higher temperature of the world appeare because of overmeasure greenhouse gas. The control and recycle of CO2 was very important. The energy consumption、the interaction of nodes and the weakness of the whole system couldn’t be holded. In this paper, the process was improved, the influence factors of removal rate were analyzed, the energy consumption analysis and themal economic analysis were done.The flue gas in coal-fired power plant is the object in the paper, MEA chemical absorption method was selected to capture, the mechanism of MEA chemical absorption method was analyzed, the advantages and disadvantages of MEA chemical absorption method were analyzed.The process analyzed model of MEA chemical absorption method was built based on AMSIM module of PRO/II sofeware, the effect of carbon dioxide removal rate, themal load and regeneration rate with absorption temperature, absorbent flow, absorbent concentration and regeneration temperature were analyzed. the analysis results showed the higher absorption temperature was, the higher removal rate was, the better absorption temperature was 30～40℃; the higher absorbent flow was, the higher removal rate was, the better absorbent flow was round 80~120m3/h; the higher absorbent concentration was, the higher removal rate was, the better absorbent concentration was round 15%~20%; the higher regeneration temperature was, the higher regeneration rate was, the better regeneration temperature was 100℃~120℃.The themal analyzed method was analyzed based on themal first law and second law, the energy analyzed method for carbon dioxide captured system was decided, the energy analyzed model for carbon dioxide captured system was built, the heat load calculation, energy balance calculation, theory power consumption and energy analysis ?for carbon dioxide captured system was done with black-box model, the analysis results showed that the separation rate was 12.8%. The exergy analyzed model for carbon dioxide captured system was built according to exergy analyzed method, the exergy analysis and exergy consumption analysis were done to system and subsystems with black-box model, the analysis results showed that the exergy efficiency of reboiler was lowest, the exergy consumption of absorption was very high. the regeneration exergy consumption was analyzed, the results showed the higher absorbent concentration could decrease regeneration exergy consumption, but absorbent concentration had a highest valueφmax; the higher the regeneration degreeξwas, the lower the regeneration exergy consumption qs tr, butξhad a limit value; the high property poor and rich exchanger could decrease regeneration exergy consumption.The themal economic analysis method for captured system was built based on themal economy, the themal economic analysis model and energy cost equation were built, the optimizing objective function was determined, and the themal economic analysis was done, the result showed that the cost of recycle CO2 was 582 per tun.The solution of energy-saving and consumption reducing was discussed. The theory basis and economic basis were established for energy-saving and optimization thenology of carbon dioxide captured system with chemical absorption method according to the study in this paper.更多还原