年产50万吨对二甲苯生产工艺计算

发布时间：2018-01-06 14:15

本文关键词：年产50万吨对二甲苯生产工艺计算　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：对二甲苯(PX)是石化工业的基本有机原料之一,在化纤、合成树脂、农药、塑料、医药等众多化工生产领域有着广泛的用途,主要用来生产对苯二甲酸(PTA)或对苯二甲酸二甲酯(DMT)。近年来,由于我国聚酯行业迅猛发展,带动了PTA消费量的猛增,从而导致PX的消费量也快速增长,PX的进口依存度一直高居不下,国内供应增速跟不上需求增长步伐。随着我国今后几年PX产能的快速增长,加快PX产业的清洁、高效综合发展已成为我国聚酯行业可持续发展的一项重要课题。本文通过对传统、新兴工艺方案进行对比分析,选择一种清洁、经济、高效的工艺路线；采用Aspen Plus软件完成了各工段流程模拟及全流程的模拟；同时完成了各工段及全流程物料衡算及能量衡算。主要结果如下：(1)原材料是工艺方案的出发点,它的合理选择是有效利用资源减少废物产生的关键因素。本文通过查阅资料确定了原料及产品方案。确定以产能过剩的甲醇、混合芳烃为原料,以年产量50万吨为目标生产对二甲苯,副产包括苯、邻二甲苯的产品方案。经过工艺方案的综合比较,本文采用歧化与烷基转移-烷基化-异构化联合工艺生产对二甲苯,最大限度地、综合高效的利用原料中甲苯、乙苯、间二甲苯及碳九混合芳烃,实现产品丰富,工艺的清洁。工艺路线分为四个工段单元,即混合芳烃分离工段、甲苯歧化及烷基转移工段、甲苯甲醇烷基化工段、异构化工段。同时实现了甲醇、氢气、混合芳烃的循环,变废为宝,实现高效利用。(2)通过对各单元过程的物料衡算计算,确定了原材料的消耗,主副产品的实际产量及质量指标；确定了氢气、甲醇、甲苯的循环量以及损失率等指标；确定了各设备输入及输出的物流量、摩尔分率及组成；同时确定了废气、废水排放的位置、数量及组成,这为后续三废处理提供设计依据；物料衡算为能量衡算计算提供依据。原材料消耗：混合芳烃79.596万吨/年,甲醇15.05万吨/年,氢气720.28吨/年。主副产品产量：对二甲苯50.53万吨/年,质量分数99.90%；苯15.53万吨,质量分数均在91%以上；邻二甲苯15.37万吨/年,质量分数99.90%；废水：8.20万吨/年；废气：组分主要为乙烯、丙烷、乙烷、甲醇,甲烷、还含有少量的甲苯,满足清洁生产的目的。(3)通过能量衡算方法,计算所有塔设备、反应器、气液分离罐、压缩机等设备的能量流动。确定了设备的热负荷,以便为后续的设备选型及尺寸确定等提供依据。工艺计算完成了工艺系统设计的基础工作,然后通过汇总物料衡算及能量衡算数据,为开展后续的物流流程图设计及设备选型提供基础数据。
[Abstract]:PX (p-xylene) is one of the basic organic raw materials in petrochemical industry. It is widely used in chemical fiber, synthetic resin, pesticide, plastics, medicine and so on. It is mainly used in the production of terephthalate or dimethyl terephthalate. In recent years, the rapid development of polyester industry in China has led to a rapid increase in PTA consumption. As a result, the consumption of PX has also increased rapidly. The import dependence of PX has been high, the domestic supply growth rate can not keep up with the pace of demand growth, with the rapid growth of PX production capacity in the next few years. Speeding up the clean and efficient comprehensive development of the PX industry has become an important subject for the sustainable development of the polyester industry in China. This paper makes a comparative analysis of the traditional and emerging process schemes and selects a clean and economical one. Efficient process; Aspen Plus software is used to simulate the flow of each section and the whole process. At the same time, the material balance and energy balance of each section and the whole process are completed. The main results are as follows: 1) the raw material is the starting point of the process plan. The reasonable choice of it is the key factor to reduce waste generation by utilizing resources effectively. This paper determines the raw material and product plan by consulting the data, and determines that methanol with excess capacity and mixed aromatics as raw materials. The production of p-xylene is aimed at the annual output of 500,000 tons, and the by-product includes benzene and o-xylene. In this paper, p-xylene is produced by the combined process of disproportionation and alkyltransfer-alkylation-isomerization. The mixture of toluene, ethylbenzene, m-xylene and carbon-nine aromatics in raw materials is utilized to the maximum extent and efficiently. The process route is divided into four sections, that is, mixed aromatic hydrocarbon separation section, toluene disproportionation and alkylation section, toluene and methanol alkylation section. At the same time, the cycle of methanol, hydrogen, mixed aromatics is realized, the waste is changed into treasure, and the material balance of each unit process is calculated to determine the consumption of raw materials. The actual yield and quality index of main and by-product; The circulation rate and loss rate of hydrogen, methanol and toluene were determined. The material flow, molar fraction and composition of input and output of each equipment are determined. At the same time, the location, quantity and composition of waste gas and waste water discharge are determined, which provides the design basis for the following three wastes treatment. Material balance provides basis for energy balance calculation. Raw material consumption: mixed aromatics 795,960 tons / year, methanol 150,500 tons / year. Hydrogen 720.28 tons / year. Main and by-product production: 505,300 tons / year of p-xylene, 99.90 kum by mass fraction; Benzene 155,300 tons, mass fraction above 91%; O-xylene 153,700 tons / year, mass fraction 99.90; Wastewater: 82,000 tons per year; Exhaust gas: the main components are ethylene, propane, ethane, methanol, methane, but also contains a small amount of toluene, to meet the purpose of clean production. The energy flow of gas-liquid separation tank, compressor and other equipment. The heat load of the equipment is determined in order to provide the basis for the subsequent equipment selection and size determination. The process calculation completes the basic work of the process system design. Then the material balance and energy balance data are collected to provide basic data for the subsequent logistics flow chart design and equipment selection.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ241.13

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