论文总字数：23035字

摘 要

乙烯是石油化工行业最基本的化工产品之一，其产能的大小标志着一个国家、地区化工产业现代化程度的高低，具有一定的战略意义；近几年全球乙烯产量持续增长，特别是中国、中东地区乙烯工业，并且蒸汽裂解制乙烯工艺是全球最成熟、使用最广泛的工业生产方法，石脑油等低碳烃类也是最常见的裂解原料，但随着全球天然气储量的勘探以及美国的页岩气革命，乙烯原料的轻质化和生产规模大型化已成为全球乙烯发展的重要趋势。

裂解制乙烯反应主要是裂解反应，热力学表现为吸热反应，因此反应温度一般在800℃以上；链式反应理论能够很好地解释裂解反应原理以及反应进程，主要有链引发阶段、链增长阶段和链终止阶段；蒸汽热裂解制乙烯工艺主要包括管式裂解炉系统、急冷系统、压缩制冷工段和精馏分离系统等。

裂解制乙烯工业近年来事故频繁，工艺安全性较差，因此有必要对整个工艺进行全面探析，分析裂解原料及产物介质的火灾危险性和毒害性，根据燃烧特性进行危险等级划分，对工艺流程及生产设备进行危险性分析，探讨其不安全因素，表明：裂解原料及产物中基本为易燃易爆和有毒有害介质，如氢气、乙烯以及硫化氢等，若发生泄漏将会导致中毒、火灾和爆炸事故的发生，而生产装置集中体现的危害性主要有物理化学腐蚀、堵塞等引起的物料泄漏、火灾爆炸等，因此有必要针对危险性大的关键设备进行本质安全设计， 采取相关措施预防事故发生。

管式裂解炉的安全设计主要有清焦技术的设计以及相关安全防护方法的设计，裂解炉的清焦主要包括抑制结焦生炭和烧焦方法，前者主要有调整裂解原料的碳氢比，采用新型耐高温陶瓷材料，减少炉管材质对结焦生炭的金属催化以及强化炉管传热设计，后者主要有高温蒸汽、蒸汽-空气混合以及空气烧焦法，并且在线清焦技术能有效地增大焦炭清除率和缩短清焦周期；相关安全措施主要考虑泄漏、高温等危险因素，可设置易燃有毒气体报警仪，建立安全连锁装置以及自动保护系统等。

关键词：乙烯装置 易燃有毒气体 裂解反应 火灾危险性 安全技术

Abstract

Ethylene is one of the basic and primary product in petrochemical industry and its productivity determines the modernized level of chemical industry in a country or a region with strategic importance. The productivity of ethylene has steadily increased recently especially in China and the Middle East. Steam cracking for ethylene is the most mature method used widely around the world and hydrocarbons such as naphtha are the most common raw materials for cracking. But with the exploration of natural gas and the revolution of shale gas in America, the trend using light cracking materials and enlarging scale of production has been seen in the global development of ethylene.

Pyrolysis, a endothermic reaction, primarily happens in producing process and the reaction temperature is usually over 800℃. Chain reaction theory is appropriately used to explain the pyrolysis process including chain initiation, transfer and termination three stages. Technological progress of producing ethylene include tube cracking furnace system, quench system, compression refrigeration sector and distillation system.

Accidents in ethylene industry are frequent recent year and its security is poor. So it is necessary to make a comprehensive analysis of the whole process, analyzing the fire hazard and toxicity of cracking raw materials and products, classifying the dangerous grades according to the combustion characteristics and analyzing the process and equipment of production to explore the dangerous and harmful factors. The results show that the cracking raw materials and products are explosive and toxic media, such as hydrogen, ethylene and hydrogen sulfide. If the leakage occurs, it will lead to poisoning, fire and explosion accidents. The main hazards in the production devices are leakage and explosion primarily caused by physical and chemical corrosion, blockage, etc. Therefore, it is necessary to make essential safety design of key equipment and take relevant measures to prevent accidents.

The safety design of furnace mainly includes the design of coke cleaning technology and related safety protection methods. The coke cleaning of cracking furnace mainly includes restraining coke’s formation and burning coke. The former mainly includes adjusting the carbon-hydrogen ratio of raw materials, adopting new ceramic materials resisting high temperature, reducing the metal catalysis to coke’s formation and strengthening the heat transfer design of furnace, while the latter mainly includes coke-burning by high-temperature steam, the mixture of steam and air and pure air. Besides online coke-cleaning technology can effectively increase coke clearance rate and shorten the coke-cleaning cycle. The related safety measures mainly consider risk factors such as leakage and high temperature such as setting the combustible gas and harmful gas alarm unit, build up safety interlocking device and automatic protection system, etc.

Key words: Ethylene equipment, Combustible and harmful gas, Pyrolysis, Fire danger, Safety technology

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 引言 1

1.2 国内外研究现状 4

1.3 研究目的与方法 5

1.4 本章小结 6

第二章 裂解制乙烯工艺系统简介 7

2.1 裂解制乙烯生产原理 7

2.2裂解制乙烯工艺流程 8

2.2.1 管式裂解炉系统 8

2.2.2 急冷系统 8

2.2.3 压缩和制冷系统 9

2.2.4 精馏分离系统 9

2.3 本章小结 10

第三章 裂解制乙烯生产危险性分析 11

3.1介质危险性分析 11

3.1.1火灾危险性 11

3.1.2腐蚀性物料危害 12

3.1.3中毒危险性 13

3.2工艺设备危险性分析 15

3.2.1管式裂解炉 15

3.2.2急冷换热器 16

3.2.3压缩制冷循环 17

3.2.4加氢反应器 17

3.3 本章小结 20

第四章 裂解制乙烯工业生产关键装置安全设计 21

4.1 关键装置的确定 21

4.2 关键装置的安全设计 22

4.2.1 裂解炉清焦技术的设计 22

4.2.2装置的安全防护设计 23

4.3本章小结 24

第五章 结论 25

参考文献 27

本科期间参与课题与发表论文说明 29

致谢 30

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