【作者】 张茂；

【导师】 吴少华；

【作者基本信息】 哈尔滨工业大学 ， 热能工程， 2007， 硕士

【摘要】 气候变暖已经成为一个全球性的环境问题。化石能源的使用产生的大量CO₂以及地表森林植被的大面积破坏被认为是引起气候变暖的主要原因。火力发电厂是CO₂排放的大户和集中排放源。控制和减缓火力发电厂的CO₂排放,可以从提高发电效率、促进能源替代以及直接从火力发电厂的烟气中回收CO₂三个方面进行,而后者是目前控制CO₂向大气中排放和减缓气候变暖的主要措施。本文分析对比了化学吸收法、物理吸收法、物理吸附法、膜分离法和低温蒸馏法等CO₂捕集技术的流程、特点、适用范围、研究现状及经济性,指出化学吸收法是目前最有效的CO₂捕集技术,而氨水是一种全新的、比较理想的吸收剂。本文设计了利用氨水喷淋脱除燃煤烟气中CO₂的实验装置,并在该装置上完成了对CO₂进行连续脱除的实验研究。该实验装置采用阶梯环填料塔作为吸收反应器,实验中将已配制好的预设浓度的稀氨水从吸收塔顶部喷淋,与从塔底上升的模拟烟气充分混合反应,并使用红外气体分析仪连续检测反应后烟气中CO₂的体积浓度,从而得到CO₂脱除率随时间变化的曲线。本文分别研究了氨水浓度、烟气中CO₂初始浓度及温度等因素对CO₂脱除率的影响,同时采用鼓泡吸收法和酸解法研究了氨水的吸收容量,并采用傅里叶变换红外光谱仪（FTIR）对反应产物成分进行了定性的分析。实验结果表明:氨法相对于传统脱碳方法而言具有很大的优势,只要反应条件控制在合理范围内就可以实现较高的CO₂脱除率（85%以上）及脱除速度;增大氨水浓度或减小CO₂浓度都能提高CO₂脱除率;温度对CO₂脱除率的影响显著,在40℃附近CO₂脱除率最高;氨水的吸收容量为0.86mol CO₂/mol NH3,相应的质量比为2.22,高于传统的MEA法的0.4;反应产物经FTIR分析证明为碳酸氢铵,该产品是我国农业上广泛应用的氮肥,具有一定的商业价值。本文的研究对于氨水喷淋法脱除燃煤烟气中CO₂的工业应用有一定的指导意义。更多还原

【Abstract】 The global warming has become a global environmental problem. It is mainly due to the enhanced greenhouse effect produced by greenhouse gas emission into the atmosphere as a result of fossil fuels combustion and the forests cutting down in the land. Coal-fired power plant contributes more to the CO₂ emission and is a concentrative CO₂ emission source. Improving power generating efficiency, accelerating the fuel substitution and capturing CO₂ directly from the flue gas of the power plant can be taken into account to control and reduce CO₂ emission to the atmosphere, with the last being the most important method to control CO₂ emission nowadays.In this paper, flow chart, characteristic, fields of utilization, the state of the art and the economics of chemical absorption, physical absorption, physical adsorption, cryogenic distillation and membrane separation technologies et al. are analyzed and compared with each other. It indicates that chemical absorption is the most effective CO₂ capture technology and ammonia is a new reasonable absorbent.A set of experimental equipment was designed to remove CO₂ from coal-fired flue gas by ammonia spraying, and experimental study of CO₂ continuous removal was also completed by this experimental equipment which has a cascade mini ring（CMR） packed column as the reactor. In the experiment, the diluent ammonia solution was sprayed from the top of the absorption column, fully mixing and reacting with the simulative flue gas from the bottom. The volume concentration of CO₂ in the flue gas was continuously detected by Coal-Gas Analyzer, and then the curve of CO₂ removal efficiency changing in time was obtained.In this paper, the effect of several factors to CO₂ removal efficiency was studied respectively, such as ammonia concentration, CO₂ concentration and temperature. The absorption capacity of ammonia was studied by bubble absorption and acid hydrolysis. The reaction production was also analyzed by FTIR. The results demonstrate: the method of ammonia spraying excels the traditional ones for it can reach a high remonval efficiency （higher than 85%） and a rapid removal rate under a proper reaction condition. Increasing ammonia concentration or decreasing CO₂ concentration may enhance CO₂ removal efficiency. The effect of temperature to CO₂ removal efficiency is obvious, and the highest CO₂ removal efficiency appears at about 40℃. The absorption capacity of ammonia is 0.86mol CO₂/mol NH3 or 2.22 kg CO₂/kg NH3, which is higher than that of MEA. The reaction product is proved by FTIR to be NH4HCO3, which is a kind of nitrogenous fertilizer widely used in agriculture in China and has business value.The research in this paper has some guiding significance of industrial application of removing CO₂ from coal-fired flue gas by ammonia spraying.更多还原