化学吸收法捕集二氧化碳工艺的模拟及实验研究

发布时间：2018-12-11 09:38

【摘要】：温室效应引起的全球气候变暖对人类赖以生存的地球环境日益构成威胁。控制最主要的温室气体—CO2排放也逐渐成为学者们研究的热点。尽管现阶段化学吸收技术还有一定的缺点,但在所有燃烧后捕集CO2技术中,化学吸收法依然是最为成熟,也最有可能实现商业化以及工业化应用的技术之一。本文利用化工流程模拟软件Aspen Plus对化学吸收法捕集CO2工艺完成了以下三方面的工作：对氨水吸收剂脱除300MW燃煤电厂烟气中的CO2工艺流程进行了系统的模拟；对氨水吸收剂与MEA吸收剂的吸收再生特性进行了比较；对蒸汽直接吹扫再生CO2系统进行了实验及模拟工作。通过使用氨水吸收剂模拟吸收300MW燃煤电厂模拟烟气,分析吸收过程中贫液CO2负荷、流量、温度,烟气温度,吸收塔高度等因素对吸收效果的影响；再生过程中富液温度,再沸比,塔顶产品流率,冷凝温度,再生压力等因素对再生效果的影响；脱氨系统中脱氨吸收剂浓度,流量,负荷,压力等对再生脱氨洗涤效果的影响。比较了7wt%氨水吸收剂和30wt%MEA吸收剂在吸收速率,吸收容量,塔内温度分布等方面的特点。结果显示,MEA吸收剂具有更高的吸收速率,较低的吸收容量。MEA吸收剂在吸收塔内平均温度比氨水吸收剂吸收塔内平均温度要高。同时对再生过程中,再沸器热负荷,冷凝温度以及再生压力这三个重要的再生操作条件的比较,分析各自的再生特性,得出两种吸收剂在再生过程中的能耗差异。利用蒸汽直接吹扫再生CO2系统,通过实验及模拟过程分析了该工艺流程中蒸汽吹扫量,蒸汽的过热度,富液入口温度,再生压力,填料种类这五大因素对CO2再生效果的影响。研究结果显示,在这五大因素中,蒸汽吹扫量,富液入口温度对CO2再生效果影响较为明显。吹扫蒸汽过热温度对CO2再生效果没有太大影响,而再生压力对CO2再生量的影响在不同的蒸汽吹扫量下呈现出不同的趋势2在MellaPak, Mellapak plus, SuperPak, CY, IMTP这五种填料中,CY填料性能表现最好。该工艺能够有效降低再生能耗计算过程中汽化潜热部分的能耗,其相比于传统再生过程可以有效达到节能目的。在优化的操作条件下,系统可以将CO2再生能耗降至3MJ/kgCO2以下。
[Abstract]:Global warming caused by Greenhouse Effect is increasingly threatening the Earth's environment on which human beings depend. Controlling the most important greenhouse gas-CO2 emissions has gradually become the focus of scholars. Although chemical absorption technology still has some disadvantages at present, chemical absorption method is still one of the most mature, commercial and industrialized technologies of all post-combustion capture CO2 technology. In this paper, the chemical process simulation software Aspen Plus has been used to accomplish the following three aspects of the chemical absorption capture CO2 process: systematic simulation of the ammonia absorbent removal of CO2 process from the flue gas of the 300MW coal-fired power plant; The absorption and regeneration characteristics of ammonia water absorbent and MEA absorbent were compared, and the experiment and simulation work of steam direct purging and regenerating CO2 system was carried out. By using ammonia water absorbent to simulate the absorption of flue gas from 300MW coal-fired power plant, the influence of CO2 load, flow rate, temperature, flue gas temperature, height of absorption tower on absorption effect was analyzed. The effects of rich liquid temperature, reboiling ratio, flow rate of tower top product, condensation temperature and regeneration pressure on regeneration efficiency, and the effects of concentration, flow rate, load and pressure of deamination absorbent on the effect of regenerated deamination washing. The characteristics of 7wt% ammonia water absorbent and 30wt%MEA absorbent in absorption rate, absorption capacity and temperature distribution in the tower were compared. The results show that MEA absorbent has higher absorption rate and lower absorption capacity, and the average temperature of MEA absorbent is higher than that of ammonia water absorber. At the same time, the heat load, condensation temperature and regeneration pressure of the reboiler are compared in the regeneration process, and their regeneration characteristics are analyzed, and the difference of energy consumption between the two absorbers in the regeneration process is obtained. The effects of steam blowing amount, steam superheat, rich liquid inlet temperature, regeneration pressure and packing type on the regeneration of CO2 were analyzed by means of experiments and simulation. The results show that, among the five factors, the influence of steam scavenging amount and rich liquid inlet temperature on the regeneration of CO2 is obvious. The superheating temperature of blowing steam has little effect on the regeneration efficiency of CO2, but the influence of regeneration pressure on the regeneration rate of CO2 shows different trends under different steam blowing amount. 2 in the five kinds of MellaPak, Mellapak plus, SuperPak, CY, IMTP fillers, The performance of CY filler is the best. This process can effectively reduce the energy consumption of the latent heat of vaporization in the calculation of regeneration energy consumption. Compared with the traditional regeneration process, the process can effectively achieve the purpose of energy saving. Under the optimized operating conditions, the energy consumption of CO2 regeneration can be reduced to less than 3MJ/kgCO2.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701

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