CAS OpenIR
轻油催化裂解制烯烃分离工艺模拟及优化
范风铭
Thesis Advisor华超, 刘戈
2020-07-01
Degree Grantor中国科学院大学
Degree Name硕士
Degree Discipline化学工程
Keyword乙烯,丙烯,催化裂解,精馏,节能
Abstract

乙烯是主要的化工生产原料,其产量是衡量一个国家化工行业发展的重要指标。目前乙烯生产装置主要采用蒸汽裂解制烯烃技术,传统蒸汽裂解制烯烃原料来源窄、耐杂质能力弱、反应条件苛刻、装置投资高,经过几十年的发展已经难以再进行优化提升,因此各国都在探索新型高效的低碳烯烃生产技术。中国企业根据自身资源禀赋的特点,已开发了不同的低碳烯烃生产技术,如甲醇制低碳烯烃、重油催化裂解制烯烃等低碳烯烃生产技术。石脑油是炼油一体化的关键中间原料,近年来随着国内炼化一体化的深度耦合和国内大规模新建芳烃联合装置,装置富余大量石蜡基石脑油,这部分石脑油中因芳潜低不适合做芳烃原料,因辛烷值低不适合做汽油调和组分,因正异构烷烃多适合做乙烯原料,但因组分复杂含硫氮等杂质无法直接作为蒸汽裂解的原料。如何有效利用这部分石脑油资源成了国内大型化工企业提升效益的重要课题。轻油催化裂解制烯烃技术因其原料适应性强、耐杂质能力强、产品收率高、操作条件缓和、设备投资相对较低等特点,可以解决石脑油综合利用的难题,是目前低碳烯烃生产技术的研究重点。本研究基于世界首套40万吨/年轻油催化裂解制烯烃的工业示范装置运行数据,深入研究催化裂解制烯烃的工艺和过程优化。根据实际生产装置物流组成、产物组成,以轻油催化裂解制烯烃单元的高能耗分离装置为研究课题,采用分级精馏、热泵、乙烯制冷、丙烯制冷、夹点换热等措施,对深冷分离装置进行工艺和能量优化。首先通过关键组分的热力学性质研究,采用非极性体系的汽液相PR状态热力学方程,以流程稳态模拟技术作为研究方法,结合Aspen Plus商业模拟软件建立准确的的精馏分离数学模型,考察理论板数、各塔压力/温度、回流比等工艺参数对分离指标的影响。通过与工业示范生产装置对比,流程模拟与操作数据、设计数据吻合,关键位置的温度值与运行装置相差±5℃以内,关键温度误差范围在±4.5%以内,验证了数学模型的准确性。模拟计算结果显示:聚合级乙烯产品30.00%,聚合级丙烯产品23.30%,双烯烃收率为53.30%,高于传统蒸汽裂解的乙烯丙烯收率(45%~48%)。其次在模型基础上对目前装置存在能耗瓶颈进行优化。通过模拟计算、热力学与实际数据比较建立合理的工艺流程,经过数据分析和换热网络的对比等方法,优化烯烃分离流程降低能耗,建立能耗比较模型。从定性到定量,有针对性地过对每个精馏体系进行分离优化,确定最佳进料塔板位置和最优回流比。结合夹点技术和Aspen Energy Analyzer对目前装置存在能耗瓶颈进行优化,通过换热网络的优化,能量逐级利用等手段,对不同工艺流程的能耗进行计算比较,减少装置能耗。优化的研究结果与示范装置相比,现有装置总冷负荷减少10.55%,优化效果明显。综上,本文的研究内容可为轻油催化裂解制烯烃分离单元的工业化应用提供一定的理论指导。;Ethylene is the most important raw material in the bulk chemical industry, which production capacity is an important development index of industry. Most ethylene plants using steam cracking as a production technology. However, after long time developing, the steam cracking technology has a little room to improve and optimize, and also have some limitations, such as infeasibility in the feedstock, poor tolerance in impurities as sulfur or nitrogen, high temperature and pressure hot cracking reaction, high investment. Therefore, the licensors are exploring the new low-carbon olefins technologies at the present. Meanwhile, some Chinese companies approach the ethylene technologies of methane to olefins and deep catalytic cracking because of own feedstock characterization. Naphtha is the key intermediate raw materials in refining-chemical integration plants. There are a lot of paraffin-base naphtha resources in China because much refining-chemical integrations, especially aromatics complex plants, have been built on the past few years. The paraffin-base naphtha is not suitable using as feedstock of aromatics plant due to low potential aromatics, as gasoline blending component due to low octane number. It is a good material to use as ethylene feedstock because of high proportion of N-alkanes and Iso-alkanes. However it cannot be directly used as the feedstock of steam cracking plant due to sulfur, nitrogen and other impurities. There is one of topic issues on naphtha processing that refining-chemical integration companies want to use paraffin-base naphtha to produce high value-added product. The light oil catalytic cracking technology is became a research focus in the ethylene field because of its strong adaptability of different raw materials, strong resistance to impurities, higher target product yield, mild operating conditions and relatively low investment. The objective of this research work is going to find an optimizing process scheme after deeply research the operating plant of the world first 400KTA light oil catalytic cracking industrial demonstration plant. The topic of research work is to optimize the process and energy in the deep chilling separation section based on the material and product composition from real running plant, taking the high energy consumption separation unit as a focus point, adopting the measures of multi-stage distillation, heat pump, ethylene & propylene refrigeration, pinch heat exchange, etc. First of all, select vapor-liquid phase PR state thermodynamic equations of non-polar system through the study of thermodynamic properties of the key components. Building an accurate mathematical model of distillation separation by using Aspen Plus commercial simulation software, and then going to investigate the influence factors of distillation by theoretical stage, the operating pressure and temperature of column and reflux ratio. The process simulation is consistent with the operating plant by comparing key temperature. The difference temperature between simulation and real plant is within ±5℃, the error range is within ±4.5%, so the accuracy of the mathematical model is verified. According to simulation results and real plant data, the yield of polymer grade ethylene is 30.00%, propylene is 23.30%, and total is 53.30%, higher than steam cracking yields that is about 45%~48%. Secondly, the energy consumption of plant will be optimized by bottleneck analysis. The accurate model has been built through simulation calculation based on the proper thermodynamic and actual plant data. Then the research work is going to establish a comparative model to optimize the olefins splitting flow sheet to reduce energy consumption after the analysis of simulation data and compare the heat exchanger network. Each distillation system will be optimized from qualitative to quantitative, to determine the best feed stage and reflux ratio. Using pinch technology and Aspen Energy Analyzer to analysis the process bottleneck, optimizing heat exchanger by the gradual utilizing energy, reducing energy consumption after compare with difference process scheme. At last the total cold duty can be reduce about 10.55% after optimized comparing with real plant. It is reach a good optimization after simulation and analysis. Therefore, the research content of this paper can provide some theoretical guidance of olefins separation for the industrial application of light oil catalytic cracking. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/49729
Collection中国科学院过程工程研究所
Recommended Citation
GB/T 7714
范风铭. 轻油催化裂解制烯烃分离工艺模拟及优化[D]. 中国科学院大学,2020.
Files in This Item:
File Name/Size DocType Version Access License
轻油催化裂解制烯烃分离工艺模拟及优化.p(7206KB)学位论文 限制开放CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[范风铭]'s Articles
Baidu academic
Similar articles in Baidu academic
[范风铭]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[范风铭]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.