膜与PSA耦合高收率高纯度回收炼厂气中氢气

发布时间：2018-02-11 07:38

本文关键词： 氢气回收富氢气体膜耦合工艺 UniSim Design 模拟　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着人们对生存环境的日益重视,我国燃油标准不断提高,车用汽油、柴油中的硫、烯烃、芳烃含量等指标控制越来越严格；然而炼油厂为了降低原油采购成本,大幅度提高含硫、含酸、重质原油的加工比例,因此,选择清洁化的加氢技术是解决问题的主要措施。但带来的问题是,氢气的消耗量逐年大幅度的增加,已经成为了炼油过程中仅次于原油成本的第二成本。同时,在加工原油过程中产生的含氢尾气被作为燃料气使用,或由于现有的分离回收工艺比较单一,对氢气和轻烃的回收率低,造成氢气和轻烃资源的极大浪费。因此,针对某炼厂尾气的氢气回收,本论文提出利用膜分离和变压吸附(PSA)工艺的耦合技术来实现炼厂尾气中氢气组分的高收率高纯度回收,以满足清洁燃料生产需要,降低制氢装置的负荷,节约了资源和降低能耗。在原有变压吸附(PSA)装置基础上,增加氢气分离膜(HM)对现有尾气进行回收利用。设计了分别利用单级膜和PSA回收流程,回收原PSA装置解吸气及其他炼厂尾气。在此基础上,提出了二段膜和PSA回收流程,在该流程中增加第二段膜分离单元回收一段膜渗余侧气体,达到增加氢气回收率的目的。为进一步增大氢气回收率和PSA装置利用率,提出了二段膜和PSA耦合流程,通过一段氢膜分离器处理部分氢气浓度较高的重整氢原料,直接得到高纯度产品氢；氢气浓度较低的几股尾气和一段膜渗余侧气体混合进入二段膜分离器提纯到90%左右,然后作为PSA装置的原料进行氢气的提纯回收,以实现氢气回收的高纯度和高收率。利用UniSim Design软件对三种工艺流程进行模拟与优化。考察进料压力、操作压比等操作参数对氢气回收率、经济效益等结果的影响,发现随着操作压力和压力比增大,所需膜面积减小、氢气回收率增大。在不同操作条件下,分别对三种尾气回收流程进行经济核算。一级膜分离流程中,新增面积为9561m2的膜分离装置,得到浓度为98 mo1%的氢气产品,每年增加氢气回收量4683 t,将氢气回收率由71.86%提高到96.63%,年经济效益收增加1.68×108 CNY。二段膜和PSA回收流程的氢气回收率为97.51%,较单独PSA流程,回收率提高了25%左右。该流程总膜面积为24197m2,其中一段膜面积与单级膜流程基本一致。每年可回收产品氢148688 t,总收益7.85×108 CNY。二段膜分离和PSA耦合流程所需膜面积为21335m2,达到产品氢浓度99mol%的要求,氢气回收率为97.67%,年收益为7.30×108 CNY。结果表明,回收该炼厂尾气中的氢气时,不同工艺流程均受到进料压力和操作压力比等参数对经济效益具有直接影响,结构相对复杂的膜和PSA耦合工艺充分利用了膜分离和PSA装置的优势互补,有助于提高氢气回收率和氢气产品的浓度,增加经济效益。
[Abstract]:As people pay more and more attention to the living environment, the standard of fuel oil in our country is increasing, and the content of sulfur, olefins and aromatics in gasoline and diesel oil is controlled more and more strictly. However, in order to reduce the cost of crude oil procurement, the oil refinery, The processing ratio of crude oil containing sulfur, acid and heavy oil has been greatly increased. Therefore, the choice of clean hydrogenation technology is the main measure to solve the problem, but the problem is that the consumption of hydrogen is increasing by a large margin year by year. At the same time, the hydrogen-containing tail gas produced during the processing of crude oil is used as a fuel gas, or because the existing separation and recovery process is relatively simple. The low recovery of hydrogen and light hydrocarbons causes a great waste of hydrogen and light hydrocarbon resources. In this paper, the coupling technology of membrane separation and pressure swing adsorption (PSA) process is proposed to realize the high yield and high purity recovery of hydrogen components in refinery tail gas, so as to meet the needs of clean fuel production and reduce the load of hydrogen production plant. It saves resources and reduces energy consumption. On the basis of the original pressure swing adsorption (PSA) plant, hydrogen separation membrane (HM) is added to recycle the existing tail gas. The single stage membrane and PSA recovery process are designed, respectively. Based on the recovery of gas from the original PSA plant and other refinery exhaust gas, a two-stage membrane and PSA recovery process was proposed, in which a second membrane separation unit was added to recover the residual gas from the first stage of membrane infiltration. In order to further increase the hydrogen recovery rate and the utilization rate of PSA unit, a two-stage membrane and PSA coupling process was proposed to treat some reforming hydrogen feedstocks with high hydrogen concentration through a one-stage hydrogen membrane separator. High purity hydrogen was obtained directly, and several tail gases with low hydrogen concentration were mixed into the secondary membrane separator to be purified to about 90%, and then used as raw material of PSA unit for hydrogen purification and recovery. In order to achieve high purity and high yield of hydrogen recovery, three processes were simulated and optimized by UniSim Design software. The effects of operating parameters such as feed pressure and operating pressure ratio on hydrogen recovery and economic benefit were investigated. It is found that the required membrane area decreases and the hydrogen recovery rate increases with the increase of operating pressure and pressure ratio. A new membrane separator with an area of 9561 m2 was added to obtain hydrogen products with a concentration of 98 mol%. The hydrogen recovery rate was increased from 71.86% to 96.63 t per year, and the annual economic benefit was increased by 1.68 脳 108CNY. the hydrogen recovery rate of the two-stage membrane and PSA recovery process was 97.51%, which was higher than that of the single PSA process. The recovery rate was increased by about 25%. The total membrane area of the process was 24197m2, and the membrane area of the first segment was basically the same as that of the single-stage membrane process. The recoverable product hydrogen was 148688 tons per year, and the total revenue was 7.85 脳 108CNY. the membrane area required for the two-stage membrane separation and PSA coupling process was 21335m2. Reaching the requirement of 99mol% hydrogen concentration, The hydrogen recovery rate is 97.67 and the annual income is 7.30 脳 108CNY. the results show that when the hydrogen is recovered from the tail gas of the refinery, the different technological processes are directly affected by the parameters such as feed pressure and operating pressure ratio on the economic benefits. The membrane and PSA coupling process with relatively complex structure makes full use of the advantages of the membrane separation and the PSA unit to complement each other, which is helpful to increase the hydrogen recovery rate and the hydrogen product concentration and increase the economic benefit.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.2;X742

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