分类号：学校代码：10426
密级：学号：**********
硕士学位论文
MASTER DEGREE THESIS
作者：冯艺荣
****：***
学科专业：化学工程与技术
空腔效应
专业代码：081700
研究方向：绿化学工艺
2018年4 月3 日
摘要
煤气化废水酚氨回收工艺流程的分析和改进
摘要
煤气化废水在煤气生产制造的洗涤、冷凝和分馏部分排出。该水的特征表现在生物难以分解、组成多样、污染物浓度大，其中氨和酚类物质被认为是首要治理污染物。酚氨回收工艺流程主要由酸水汽提塔、萃取和溶剂回收系统组成，可有效脱除这类污染物。谋杀章鱼保罗
经由煤气化废水成分的检测，选取代表性组分，创建了模拟该废水的热力学模型，并以此完成了现存的酚氨回收流程稳态操作的模拟，得到了该工艺过程中各操作单元的运行条件。然后，以酸水气提塔为例，运用动态模拟考察其在面对某些干扰过程时的动态表现。结果表明通过控制酸性气体流量来控制塔顶温度的控制方案具有较好的控制性能，系统运行稳定、易于操作。 日本人眼里的中国
为了进一步实现节能的目的，本文基于现有废水处理流程提出了一种酸水汽提塔和溶剂回收系统热集成的酚氨回收工艺。在此提出的工艺中，将酸水汽提塔侧线抽出的富氨气用作热源，分别与后一阶段的溶剂汽提塔和溶剂汽提塔的再沸器进行热交换。在相同的产品纯度设计规定下，操作成本比现有流程节省约34%，年度化总费用可降低约30.8%。
此外，萃取溶剂的遴选对酚回收流程和经济价值的产生很有影响。本文通过量子化学计算发现甲基戊烯酮作为一种新型的萃取剂具有较高的萃取脱酚效率。随后通过多级逆流萃取实验对三种不同萃取剂（二异丙醚，甲基异丁基甲酮和甲基戊烯酮）的脱酚性能进行了研究。两者分别从理论和实验上证明了以甲基戊烯酮为溶剂的萃取性能优于二异丙醚和甲基异丁基甲酮。经萃取工段后，总酚的浓度可从5000 mg/L减小至250 mg/L范围内。热力学数据库是单元模型不可或缺的组成，随后，测定出甲基戊烯酮溶剂和含酚水体系的液液相平衡，再关出一些热力学参数，为基于此的新流程的开发准备好了数据依据。最后，本文初步开发出了用含有甲基戊烯酮溶剂的酚回收流程。两种改进的酚氨回收工艺都兼具成本与效果优势，具有良好的应用前景。
杨白冰模式
关键词：煤气化废水酚氨回收热集成稳态模拟甲基戊烯酮
IMPROVEMENT OF PHENOLS AND AMMONIA邮礼网
RECOVERY PROCESS FOR THE TREATMENT OF
COAL GASIFICATION WASTEWATER
长江电力商务ABSTRACT
Coal gasification wastewater (CGW) is generated from the gas washing, condensation and fractionat
ion processes. These effluents are characterized by hard biodegradation, complex components and high concentration of pollutants, in which ammonia and phenols are considered as priority pollutants. Phenols and ammonia recovery process consisting of the sour water stripper, extraction and the solvent recovery system is applied to removing these pollutants.
A suitable thermodynamic model is established on the analysis and simplification of CGW. Therefore, the operating conditions of conventional phenols and ammonia recovery process are determined by steady state simulation. And dynamic simulation is performed to investigate the transient response on the influent fluctuations in case of accidents. Two control schemes are proposed and compared. The structure which the top temperature of column is controlled by manipulating the flow rate of sour gas shows better control performance. The system is running stable and easy to operate.
In order to further achieve the purpose of energy saving, an improved phenols and ammonia recovery process that the sour water stripper and the solvent recovery system are thermal integrated is proposed based on the conventional wastewater treatment process. Therein, the ammonia-rich gas drawn from the middle of sour water stripper, as a heat source, is exchanged with the reboiler of the solvent distillation column and the solvent stripper. The results show that the operating costs are
about 34% less than that of the conventional process, and the total annual costs can be decreased by about 30.8% under the same design requirements of product purity.
Besides, the extractant has a great influence on the performance and economy of the phenols recovery process. In this paper, mesityl oxide, as a novel extractant, is found with high phenols removal efficiency through quantum chemical calculations. To confirm that, the removal performance with three different solvents (diisopropyl ether
(DIPE), methyl isobutyl ketone (MIBK) and mesityl oxide) are investigated and compared via multi-stage counter-current extraction experiments. Both theoretical and experimental results identified that the performance using mesityl oxide as solvent is better than that using DIPE and MIBK. The total phenols concentration can be reduced from more than 5000 mg/L to less than 250 mg/L. The thermodynamic databases are significant for mechanism models of units. Subsequently, experimental LLE data for mesityl oxide-phenols-water system were measured and correlated with the NRTL activity coefficient model, and the corresponding binary interaction parameters were regressed. Eventually, phenols recovery process using mesityl oxide as solvent is developed and conceptual designed. Both two improved phenols and ammonia recovery processes are proven to be effective and economical processes with good application prospects.
KEY WORDS: coal gasification wastewater,phenols and ammonia recovery process, heat integration, process simulation, mesityl oxide
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