多效蒸发油田污水处理系统热力学分析与实验研究

发布时间：2018-01-20 14:44

本文关键词： 多效蒸发热力分析优化设计油田污水性能实验　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前绝大多数油田采用热力采油工艺,这就造成在原油开采过程中会产生大量的油田污水,而且一般具有成分复杂、矿化度高等特点。若仅仅采用外排、回注对其处理,不仅会造成水资源的大量浪费,而且将污染环境,因此如何对油田污水进行深度净化处理,使其能够回用于热采锅炉用水,将对采油工业产生巨大的经济效应和环保效应。本文针对深度净化处理工艺,研究了采用多效蒸发(Multiple Effect Evaporation, MEE)进行油田污水深度处理的技术可能性,从理论模拟和实验两方面对多效蒸发工艺进行了细致的研究,其中主要工作有：(1)建立了不同进料模式下MEE的Aspen Plus模型,并对其进行了热力分析,比较了不同系统的操作性能,重点探讨了蒸汽喷射器(Thermo Vapor Compressor, TVC)对MEE-TVC系统的影响规律及其原因。结果表明：①MEE与TVC耦合能显著提高MEE系统的操作性能；②对于MEE-TVC系统,存在一个最佳引射位置,合理安排TVC的引射位置,能够显著提高系统的操作性能；③TVC工作蒸汽压力的升高能提高MEE-TVC系统的性能,但其效果随着工作蒸汽压力升高而减小,因此对于MEE-TVC系统工作蒸汽压力不宜过高；④TVC混合蒸汽压力对MEE-TVC系统的影响比工作蒸汽压力的影响要显著得多,降低其混合蒸汽压力能够从多方面显著提高MEE-TVC系统的性能。(2)针对工程中广泛应用的并流MEE-TVC系统,建立了MEE-TVC耦合系统的优化设计模型,引入TVC位置变量,进一步研究了TVC引射位置对MEE-TVC操作性能的影响,将TVC操作参数和MEE系统各效操作参数统一作为集成决策变量,对系统的最优操作工况、TVC设计参数和TVC引射位置进行了综合优化设计与分析。优化模型能够同时满足等温差法和等面积法设计的要求,减少了重新建模的麻烦,并对这两种情况进行了比较,确定了TVC最优引射位置。(3)分别采用NaCl盐溶液、油田污水盐溶液对多效蒸发系统进行了系统性实验,主要探讨了进料流量以及浓度对系统各效操作状态和热力性能的影响规律。结果表明：进料流量对系统的操作状态影响显著,进料流量不同各效真空度也不同,进料流量和蒸汽流量存在匹配关系,当两者流量匹配最佳时,系统的造水比最大。通过对产品水质的分析,表明产品水质能够达到锅炉给水的水质要求,表明了多效蒸发系统用于污水深度净化的可行性。此外对改造后实验系统建立了各效操作状态的预测模型,通过与实验的对比证明了该数学模型的可靠性,为实验过程的动态优化调整给出方向,起到了指导作用。
[Abstract]:At present, most oilfields adopt thermal oil recovery technology, which will result in a large number of oilfield sewage in the crude oil production process, and generally have the characteristics of complex components, high salinity and so on. Reinjection will not only cause a large amount of waste of water resources, but also pollute the environment, so how to treat oilfield sewage deeply so that it can be reused in hot recovery boiler water. It will have huge economic and environmental effects on the oil recovery industry. This paper aims at the advanced purification process. The technical possibility of advanced treatment of oilfield wastewater using multiple Effect evolution (Mee) was studied. In this paper, the multi-effect evaporation process is studied from the aspects of theoretical simulation and experiment. The main work is to establish the Aspen Plus model of MEE under different feed modes. The thermodynamic analysis was carried out, the operation performance of different systems was compared, and the steam ejector Thermo Vapor Compressor was discussed emphatically. The effect of TVC on MEE-TVC system and its causes are analyzed. The results show that the coupling of TVC and TVC can improve the performance of MEE system. (2) for MEE-TVC system, there is an optimal ejection position, and the operation performance of the system can be improved by arranging the ejection position of TVC reasonably. 3The performance of MEE-TVC system can be improved by increasing the working steam pressure, but the effect decreases with the increase of the working steam pressure. Therefore, the working steam pressure of MEE-TVC system should not be too high. 4the influence of mixed steam pressure of TVC on MEE-TVC system is much more significant than that of working steam pressure. Lowering the mixed steam pressure can significantly improve the performance of MEE-TVC system in many ways) and aim at the concurrent flow MEE-TVC system which is widely used in engineering. The optimal design model of MEE-TVC coupling system is established and the influence of TVC ejection position on the performance of MEE-TVC is further studied by introducing the TVC position variable. The TVC operating parameters and the MEE operating parameters are taken as the integrated decision variables, and the optimal operating conditions of the system are obtained. The design parameters of TVC and the ejection position of TVC are comprehensively optimized and analyzed. The optimization model can meet the requirements of the isothermal difference method and the equal area method at the same time, thus reducing the trouble of remodeling. By comparing the two conditions, the optimal injection position of TVC is determined. The NaCl salt solution and the oilfield sewage salt solution are used to carry out systematic experiments on the multi-effect evaporation system. The effect of feed flow rate and concentration on the operating state and thermal performance of the system is mainly discussed. The results show that the feed flow rate has a significant effect on the operating state of the system, and the vacuum degree of the different feed flow rate is also different. There is a matching relationship between feed flow and steam flow. When the two flows match best, the water ratio of the system is the largest. Through the analysis of the product water quality, it shows that the water quality of the product can meet the water quality requirements of boiler feed water. The feasibility of the multi-effect evaporation system for the deep purification of sewage is demonstrated. In addition, the prediction model of the operation state of each effect is established for the modified experimental system, and the reliability of the mathematical model is proved by comparison with the experiment. It provides the direction for the dynamic optimization adjustment of the experiment process and plays a guiding role.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X741

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