【作者】 段振红；

【导师】 贺高红；

【作者基本信息】 大连理工大学 ， 化学工程与技术， 2010， 硕士

【摘要】 随着工业的发展,石油资源有限的储量与日益增长的需求量已成为人们关心的大问题。与此同时,石油重质化程度逐渐增大,因此,各大炼厂普遍加设了催化裂化、加氢裂化及渣油焦化等转化过程。这些过程产生大量的炼厂气,如不合理的利用,将会降低能源的利用率,造成资源的浪费。采用单一分离工艺处理富气产生的二次尾气等炼厂贫气中仍含有较多的轻烃和氢气,因此有必要开发具有高分离效率和回收率的分离工艺来回收该部分资源,减少资源浪费,提高经济效益。本文针对两种典型的炼厂气采用单一分离技术产生的二次尾气为原料,基于传统的压缩冷凝轻烃回收工艺,设计了多种采用膜强化的轻烃冷凝回收工艺,并对设计工艺采用UniSim Design模拟软件进行模拟优化。论文以催化裂化干气经膜分离回收氢过程中产生的渗余气为原料气,基于传统的压缩／冷凝工艺(SCS),设计了后置有机蒸气膜富集冷凝尾气中轻烃强化回收工艺(SC-VM)。对SCS工艺和SC-VM工艺进行模拟优化,确定了各自的最优操作参数,以经济效益为评价流程优劣的最终标准,SC-VM工艺为较优的方案。当渗余气为350kmol/h的时候,采用SC-VM工艺可回收轻烃51720吨／年,轻烃回收率由传统的压缩／冷凝工艺(SCS)的79.7%提高到98.8%,价值高达23274万元／年,公用工程消耗为2071.7万元／年,单耗为0.4006元／千克,年经济效益预计为13170万元,比SCS工艺年经济效益增加4068万元。以加氢裂化干气经PSA处理过程中产生的解吸气为原料气,基于传统的压缩／冷凝工艺(SCS),设计了分别采用后置有机蒸气膜富集冷凝尾气中轻烃强化回收工艺(SC-VM)和前置氢膜浓缩轻烃以强化其冷凝回收的工艺(HM-SC)。对SCS工艺、SC-VM和HM-SC工艺进行模拟与优化,确定了各自的最优操作参数,以经济效益为评价流程优劣的标准,HM-SC工艺为最优的方案。当解吸气为400kmol／h时,采用HM-SC工艺可回收轻烃约27333吨／年,轻烃回收率由传统的压缩冷凝工艺(SCS)的55.6%提高到75.0%,价值12299.7万元,浓度为92mol%的副产氢气产量可达到2271万Nm3／年,价值高达2498万元／年,公用工程消耗约1226.7万元／年,单耗为0.4500元／千克,年经济效益预计为8523.4万元,比SCS工艺年经济效益增加4445万元,比SC-VM工艺年经济效益增加154万元。结果表明,经膜分离强化的轻烃回收工艺可以明显提高轻烃的回收率和生产过程的经济效益,对生产具有一定的指导作用。更多还原

【Abstract】 With the development of modern industry, the inconsistence between limited reserves of oil resources and increasing demand has become a big issue that attracts more and more attention. But with the transition of focus on high quality oil, the introduction of some conversion processes generated a large amount of refinery gas, such as the process of catalytic cracking, hydrocracking, residuum coking etc. It is a serious waste of petroleum resource if this part of refinery gas cannot be used efficiently. The secondary vent gas was generated in the single separation process while treating rich gas and the poor gas from refinery still contain much light-hydrocarbons and hydrogen. In order to recovery the resource, a couple process, which has high separation efficiency and recovery ratio, is necessary to be developed to reduce the waste of resource and promote economic profit. In this paper, two kinds of secondary vent gases which were remained after single separation process were investigated as raw materials. Based on the traditional shallow condensation process, a modified shallow condensation process enhanced by various membranes was designed for light-hydrocarbons recovery from refinery gases. The designed process was simulated and optimized by the Unisim Design software.In this paper, using the residual gases generated in the process of membrane separation of hydrogen from catalytic cracking gas as raw materials and based on traditional shallow condensation system(SCS), a shallow condensation-vapor membrane (SC-VM) process with back organic vapor membrane was designed to enhance the light-hydrocarbons recovery. Both of the SCS and SC-VM processes were simulated and optimized and finally the optimal parameters were achieved respectively. In comparison to traditional condensation system, SC-VM coupling process was the optimal choice through economic analysis. When the flow rate of residual gas is about 350mol/h, the mass flow of recoveried light-hydrocarbons was 51720t/a and the recovery ratio was improved from 79.7%to as high as 98.8%, the total value of which was about 232.74 million yuan per year. The annual utilities consumption was about 20.72 million yuan, and the specific energy consumption was 0.4006yuan/kg. The economic profit of the couple process was to be 131.70 million yuan per year, which was 40.68 million yuan more than that of the SCS process.Using the desorption gas of PSA purifying H2 from hydrocracking gas as raw materials, a series of modified shallow condensations were designed for light-hydrocarbons recovery from refinery gases with rubbery membranes for light-hydrocarbons enrichment and glassy membranes for hydrogen removal. Based on the traditional shallow condensation system, SC-VM coupling process and HM-SC coupling process were presented for enhancement of the recovery of light-hydrocarbons. At last the respective optimal operation parameters were achieved by simulation and optimization of the two coupling processes.In comparison to other processes, HM-SC coupling process with two stages was the optimal one based on the enconomical analysis. When the flow rate of desorption gas was 400 kmol/h,:the mass flow of the light-hydrocarbons was bout 27333t/a, and the recovery ratio was increased from 55.6%to 75.0%, the value of which was 122.997 million yuan. The yield of byproduct hydrogen with a concentration of 92mol% can be as high as 22.71 million Nm3/h and the total profit of the gas is 24.98 million yuan. The utilities consumption was 12.27million yuan per year, and the specific energy consumption was 0.4500yuan/kg. The economic profit the HM-SC process was about 85.23 million yuan per year, which was 44.45 million yuan more than that of the SCS process and 1.54 million yuan more than that of the SC-VM process.The results showed that the the membrane enhanced shallow condensation process can improve the recovery ratio of light-hydrocarbons and economic profit obviously,. The conclusion gives directions to the future work.更多还原