年产3.0万吨二甲醚装置分离精馏工段的设计_毕业设计

兰州交通大学毕业设计（论文）

年产3.0万吨二甲醚装

置分离精馏工段的设计

学院：化学与生物工程学院

专业：化学工程与工艺

年产3.0万吨二甲醚装置分离精馏工段的设计

摘要

随着社会的发展，能源问题日益成为人们所关注的热门话题，二甲醚作为燃料可代替液化石油气成为可能。二甲醚的合成技术来源主要有甲醇脱水法和一步直接合成法，甲醇脱水法有甲醇液相脱水法和甲醇气相脱水法。相比于甲醇合成法，一步合成法具有流程短、投资省、能耗低且可获得较高的单程转化率的优点。

制取二甲醚的最新技术是从合成气直接制取，相比较甲醇脱水制二甲醚而言，一步法合成二甲醚因为体系存在有未反应完的合成气以及二氧化碳，要得到纯度较高的二甲醚，分离过程比较复杂。合成气法现多采用浆态床反应器,其结构简单,便于移出反应热,易实现恒温操作，它可直接利用CO含量高的煤基合成气,还可在线卸载催化剂。本设计主要针对分离中的精馏工序进行工艺设计，分离二甲醚、甲醇和水三元体系。一步反应后产物分为气液两相，气相产物二甲醚被吸收剂吸收后送入解吸装置，液相甲醇、水进入甲醇分离系统对甲醇进行提纯，以便甲醇的再循环，部分二甲醚根据要求的纯度，从第二精馏塔加入。在设计过程中涉及到二甲醚分离塔的工艺计算包括物料衡算、热量衡算、操作条件等；设备的计算包括塔板数、塔高、塔径等；还有附属设备主要是换热器和泵的设计与选型。最后再通过流体力学演算证明各指标数据是否符合标准。

关键词：二甲醚合成分离三元体系精馏

Annual output of 30,000 tons of dimethyl ether distillation section in the design of separation device

Abstract

With the development of society, the energy problem has become the hot topic of concern, two ether as fuel can replace liquefied petroleum gas become possible. Two ether synthesis technology the main source of methanol dehydration method and one-step direct synthesis, methanol dehydration of methanol liquid-phase dehydration and methanol gas dehydration. Compared to methanol synthesis, one step synthesis

method has short technological process, saving investment, low energy consumption and can obtain higher one-way conversion advantages. Preparation of two methyl ether of the latest technology is directly prepared from synthesis gas, methanol dehydration to dimethyl ether is two, one step synthesis of two methyl ether because the system has not full reaction synthesis gas and carbon dioxide, to obtain high purity two ether separation process is more complex. Synthesis gas method is now adopted a slurry bed reactor, which has the advantages of simple structure, convenient from the reaction heat, easy to realize constant temperature operation, it can be directly used in high CO content in coal based syngas, also available online unloading catalyst. This design is mainly for the separation of distillation process for process design, separation of two methyl ether, methanol and water three element system of. One step reaction product is divided into gas-liquid two phase, gas phase product two ether is absorbent to desorption device, liquid phase methanol, water enters into a methanol separation system for methanol purification, so that recycling part two ether methanol, according to the requirements of the purity, from the second distillation column to join. In the design process involves two ether separation process calculation including material balance, heat balance, the operation condition of equipment; calculated including plate number, tower, tower diameter; and ancillary equipment is the main heat exchanger and pump selection and design. Finally, through the fluid mechanics calculation of the index data are consistent with the standard of proof.

Keywords: DME synthesis separation ternary system distillation

目录

第一章绪论

一、概述

（一）设计规模及设计要求