论文总字数：24685字

摘 要

垃圾的产量与人们生活水平及社会发展程度有很大关系，由于垃圾产量越来越多，对垃圾的一系列处置是否得当直接关系到我们的环境问题。若不加处理直接将垃圾填埋气排入大气，不仅会造成大气污染还会加剧温室效应。通过处理可以使垃圾填埋气变废为宝，其中利用垃圾填埋气制甲醇是一种可取的方式。

本文利用化工过程模拟软件Aspen Plus，完成对基于膜分离进行合成气调比的垃圾填埋气制甲醇工艺过程的建模及全流程工艺模拟计算。此工艺模型包括一个重整单元，一个甲醇合成单元与一个循环单元。在重整单元中， LFG与蒸汽混合重整产生合成气。同时，通过调节膜分离装置分离出去的CO₂的量，调节合成气中各气体的比率，使其满足甲醇合成单元的要求，进而生产目标产物甲醇。甲醇合成后，未反应的合成气被循环到甲醇合成和重整单元，以提高能量效率。针对该垃圾填埋气制甲醇工艺，分析不同操作条件下的生产性能。通过调节循环比率，考察不同循环比率下的甲醇产量、CO₂减排效率。分析不同循环比率对热效率和碳效率的影响。

研究发现，循环比率越大，甲醇的产量、碳效率、热效率以及CO₂的减排效率也越高，我们可以适当的增加循环比率来提高总CO₂转化率，从而减少CO₂气体的排放，并获得适当的甲醇产量及经济效益。

关键词：垃圾填埋气 合成气 膜分离 甲醇 工艺模拟

Process simulation of a landfill gas-to-methanol process combined with membrane separation for syngas ratio adjustment

Abstract

The output of garbage has a lot to do with people's living standards and social development. As the output of garbage is increasing, whether a series of disposal is appropriate or not is directly related to our environmental problems. If the landfill gas is directly discharged into the atmosphere without treatment, it will not only cause atmospheric pollution but also aggravate the greenhouse effect. Landfill gas can be turned into waste through treatment. The way of landfill gas to produce methanol is one of the most desirable methods.

In this paper, We need Aspen Plus which is a chemical process simulation software. It can help us to complete the simulation of a landfill gas-to-methanol process combined with membrane separation for syngas ratio adjustment. The process model includes a reforming unit, a methanol synthesis unit and a circulation unit. In the reformer unit, LFG is mixed with steam and reformed to produce syngas. At the same time, by adjusting the amount of CO₂ separated by the membrane separation device, the ratio of each gas in the synthesis gas is adjusted to meet the requirements of the methanol synthesis unit, and then the target product methanol is produced. After methanol synthesis, unreacted synthesis gas is recycled to the methanol synthesis and reforming unit to improve energy efficiency. The technical performance of the landfill gas to methanol process under different operating conditions was compared and analyzed. By adjusting the recycle ratio, the methanol production and CO₂ emission reduction efficiency under different recycle ratios were investigated. Analyze the effects of different recycle ratios on thermal efficiency and carbon efficiency.

The study found that the larger the recycle ratio, the higher the methanol output, carbon efficiency, thermal efficiency, and CO₂ emission reduction efficiency. We can increase the recycle ratio appropriately to increase the total CO₂ conversion rate, thereby reducing CO₂ gas emissions and obtaining appropriate Methanol output and economic benefits.

Key Words: Landfill gas; synthesis gas;membrane separation; methanol; process simulation

目 录

摘要 I

ABSTRACT II

目 录 III

第一章 绪论 1

1.1 课题研究背景及意义 1

1.2垃圾填埋气的特点 7

1.2.1垃圾填埋气的产生 7

1.2.2垃圾填埋气的组成 7

1.2.3影响垃圾填埋气产生的因素 7

1.2.4加速填埋气产生的措施 7

1.2.5我国垃圾填埋气的特点 8

1.3垃圾填埋气的利用 8

1.3.1 垃圾填埋气的收集 8

1.3.2垃圾填埋气的净化 10

1.3.3垃圾填埋气利用现状 10

1.3.4垃圾填埋气资源化开发对策 10

1.4垃圾填埋气与甲醇生产 11

1.4.1甲醇及其制备的方法 11

1.4.2垃圾填埋气制甲醇 12

1.5 本课题要研究的问题 12

第二章 材料与方法 14

2.1 14

2.2 工艺建模 14

第三章 结果与讨论 18

3.1循环比率对该工艺生产性能的影响 18

3.2不同循环比率对热效率和碳效率的影响 19

3.3不同循环比对合成气中 CO₂ / (CO₂ CO) 比率、总CO₂ 转化率的影响 21

3.4本章小结 23

第四章 结论与展望 24

4.1结论 24

4.2展望 24

参考文献 26

致谢 28

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