膜—吸收耦合流程脱除催化裂化干气中丙烯的研究
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摘要
为了充分利用催化裂化干气中较低浓度的乙烯资源，国内某些炼油厂与科研院所共同开发了干气直接制乙苯工艺。但在实际生产中，该工艺存在一个主要问题：干气中丙烯浓度较高，与苯发生副反应，使干气制乙苯工艺中苯耗、能耗和催化剂损失量增大。因此，降低原料气中丙烯的浓度是一个亟待解决的问题。现有工艺中，主要通过调节催化裂化吸收稳定系统来降低丙烯浓度。该方法需要增加吸收剂流量和降低吸收操作温度，显著增加了过程的能耗及塔操作负荷。本文在现有工艺的基础上，提出了膜分离技术与吸收稳定系统耦合的新工艺，并采用HYSYS进行模拟，在能耗增加较少的情况下，满足了降低乙苯原料干气中丙烯浓度的要求。
本论文基于炼油厂提供的实际流程及装置标定数据，应用HYSYS建立了吸收稳定系统的模型，模拟得到的结果与实际生产情况吻合良好，验证了模型的可靠性。
在建立吸收稳定系统模型的基础上，调节吸收剂流量及温度、稳定塔回流比、解吸塔进料温度等参数，考察了各因素对装置能耗及系统产品干气、液化气和稳定汽油质量的影响；并改变系统操作参数，将干气中的丙烯由现有工艺的1.1％(v)降低到0.3％(v)，而总冷热负荷则是原来的2.08倍和2.22倍，无法与分馏系统提供热量匹配。
鉴于调节参数后工况无法匹配分馏系统提供的热量，本文提出了膜分离与吸收稳定系统耦合的新工艺，包括吸收塔前串联膜分离、吸收塔后串联膜分离及再吸收塔后串联膜分离三种新工艺，并应用HYSYS软件对新工艺进行了模拟计算。结果表明，采用了膜分离技术的新工艺能显著降低系统的能耗，在干气指标为丙烯浓度0.3％(v)时，上述三种新工艺的冷负荷分别降低了42.4％、28.2％、29.2％，热负荷降低了44.5％、31.3％、31.6％。综合考虑各方案的冷热负荷、塔负荷和经济效益，吸收塔前串联膜分离器是降低丙烯浓度的最佳新工艺。通过对系统热量分析，可知最佳新工艺与分馏系统提供的热量匹配，能与分馏系统做为一个整体应用于实际生产中。
In order to make use of the residual ethylene in dry gas of fluid catalytic cracking (FCC), some domestic oil refineries together with scientific research academies developed the technology of preparing ethylbenzene with ethylene in dry gas. However, the consumptions of ethylbenzene, energy and catalyst were increased due to the high concentration of propene in dry gas. In practical production, the adjustments of technical parameters for the absorption-stabilization system, such as increasing absorbent flux and lowering absorbent temperature, were used to reduce the concentration of propene in dry gas. Yet this method demanded high consumption of energy. To solve this problem, a new technology of combination of membrane technology and absorption-stabilization system was proposed in this work. Through simulation by HYSYS, it is shown that the new technology not only reduces the energy consumption, but also accords with the requirement of propene concentration in dry gas. This paper mainly includes:
The model for absorption-stabilization system is established by HYSYS. And the simulating results tally with practical data, which indicates that calculation methods and property data are accurate and credible, i.e. the model accords well with practical production.
Through the analysis of the flux and temperature of absorbent, reflux ratio in stabilization column, the temperature of feed gas in desorption column are investigated, and their effects on energy consumption and the weight of dry gas, stable gasoline and liquefied petroleum gas(LPG) are ascertained.
By changing the technology parameters, the concentration of propene in dry gas reduced from 1.1%(v) in Operating Condition 1 to 0.3%(v) in Operating Condition 2. However, the cold and hot energy consumptions of Operating Condition 1 decrease by 108% and 122% respectively compared with those of Operating Condition 2.
Considering the high energy consumption of Operating Condition 2, coupling technology of membrane separation and absorption-stabilization system is proposed in this paper. The new technology can be alternative processes, i.e. membrane separator before absorber, membrane separator after absorber, and membrane separator before the second absorber. Compared with the practical process, the cold and heat load of the new ones decrease by 42.4%, 28.2%, 29.2% and 44.5%, 31.3%, 31.6% respectively. In comprehensive consideration of the cold and heat load in column and economic analysis, coupling membrane separator before absorber column is the optimum process. Through system heat analysis, it is known the new technology, i.e. coupling membrane separator before absorber column can match well with the energy supplied by fractionation system, and can apply in production practice integrating with the fractionation system.
本论文基于炼油厂提供的实际流程及装置标定数据，应用HYSYS建立了吸收稳定系统的模型，模拟得到的结果与实际生产情况吻合良好，验证了模型的可靠性。
在建立吸收稳定系统模型的基础上，调节吸收剂流量及温度、稳定塔回流比、解吸塔进料温度等参数，考察了各因素对装置能耗及系统产品干气、液化气和稳定汽油质量的影响；并改变系统操作参数，将干气中的丙烯由现有工艺的1.1％(v)降低到0.3％(v)，而总冷热负荷则是原来的2.08倍和2.22倍，无法与分馏系统提供热量匹配。
鉴于调节参数后工况无法匹配分馏系统提供的热量，本文提出了膜分离与吸收稳定系统耦合的新工艺，包括吸收塔前串联膜分离、吸收塔后串联膜分离及再吸收塔后串联膜分离三种新工艺，并应用HYSYS软件对新工艺进行了模拟计算。结果表明，采用了膜分离技术的新工艺能显著降低系统的能耗，在干气指标为丙烯浓度0.3％(v)时，上述三种新工艺的冷负荷分别降低了42.4％、28.2％、29.2％，热负荷降低了44.5％、31.3％、31.6％。综合考虑各方案的冷热负荷、塔负荷和经济效益，吸收塔前串联膜分离器是降低丙烯浓度的最佳新工艺。通过对系统热量分析，可知最佳新工艺与分馏系统提供的热量匹配，能与分馏系统做为一个整体应用于实际生产中。
In order to make use of the residual ethylene in dry gas of fluid catalytic cracking (FCC), some domestic oil refineries together with scientific research academies developed the technology of preparing ethylbenzene with ethylene in dry gas. However, the consumptions of ethylbenzene, energy and catalyst were increased due to the high concentration of propene in dry gas. In practical production, the adjustments of technical parameters for the absorption-stabilization system, such as increasing absorbent flux and lowering absorbent temperature, were used to reduce the concentration of propene in dry gas. Yet this method demanded high consumption of energy. To solve this problem, a new technology of combination of membrane technology and absorption-stabilization system was proposed in this work. Through simulation by HYSYS, it is shown that the new technology not only reduces the energy consumption, but also accords with the requirement of propene concentration in dry gas. This paper mainly includes:
The model for absorption-stabilization system is established by HYSYS. And the simulating results tally with practical data, which indicates that calculation methods and property data are accurate and credible, i.e. the model accords well with practical production.
Through the analysis of the flux and temperature of absorbent, reflux ratio in stabilization column, the temperature of feed gas in desorption column are investigated, and their effects on energy consumption and the weight of dry gas, stable gasoline and liquefied petroleum gas(LPG) are ascertained.
By changing the technology parameters, the concentration of propene in dry gas reduced from 1.1%(v) in Operating Condition 1 to 0.3%(v) in Operating Condition 2. However, the cold and hot energy consumptions of Operating Condition 1 decrease by 108% and 122% respectively compared with those of Operating Condition 2.
Considering the high energy consumption of Operating Condition 2, coupling technology of membrane separation and absorption-stabilization system is proposed in this paper. The new technology can be alternative processes, i.e. membrane separator before absorber, membrane separator after absorber, and membrane separator before the second absorber. Compared with the practical process, the cold and heat load of the new ones decrease by 42.4%, 28.2%, 29.2% and 44.5%, 31.3%, 31.6% respectively. In comprehensive consideration of the cold and heat load in column and economic analysis, coupling membrane separator before absorber column is the optimum process. Through system heat analysis, it is known the new technology, i.e. coupling membrane separator before absorber column can match well with the energy supplied by fractionation system, and can apply in production practice integrating with the fractionation system.
引文
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[2] 刘东宁．稀乙烯法与纯乙烯法合成乙苯的技术经济对比．石油化工技术经济，2003，19(02)：27-30．
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[5] Dwyer F G. US:4107224,1978.
[6] Hogopian C R, Lewis P J, McDonald J J. Evaluate Styrene Production. Hydrocarbon Process, 1983,62(2):45-48.
[7] Tsukumo H, et al. European Styrene Catalyst Symposium, Munich, Germany, 1991.
[8] Smith J R, Lawrence A. US:4849569.
[9] 王清遐，蔡光宇，黄祖贤等．催化裂化干气中乙烯制乙苯的催化剂研究．催化学报，1990，11(03)：236-241．
[10] 何祚云，李建新，朱青．炼厂催化干气稀乙烯制取乙苯／苯乙烯利用方案分析．当代石油石化，2005，13(03)．
[11] 杨立英，王志良，张吉瑞等．在FX-02沸石催化剂上苯与乙烯烷基化反应的工艺条件研究．石油炼制与化工，1998，29(11)：54-56．
[12] 陈俊武．催化裂化工艺与工程．北京：中石化出版社，2005．
[13] 抚顺石油二厂重油催化车间．重油催化裂化装置工艺技术规程，2003．
[14] 杨锦明，吕家卓．采用高效塔盘和填料综合成组技术改造催化主分馏塔．化工进展，2005，24(12)：1414-1418．
[15] 王洪国，杨臻．CTST高效立体塔板在催化分馏塔上的应刚．化工设备与防腐蚀，2003，(03)：53-54．
[16] 张国才．0.60Mt／a重油催化裂化装置技术改造．炼油设计，2001，31(03)：32-35．
[17] 成枫，房殿孝，毕彬等．催化裂化分馏塔采用规整填料的改造设计．炼油设计，1992，22(4)：59-61．
[18] Golden S W, Martin G R, Sloley A W. FCC main fractionator revamps. Hydrocarbon Processing, 1993,77-81.
[19] 范文军，王德会．催化裂化主分馏塔改造．炼油技术与工程，2003，33(03)：46-49．
[20] 张金良，李奎武，优化工艺提高催化裂化装置柴油收率．石化技术，2000，7(04)：197-200．
[21] 杨科，催化裂化装置主分馏塔工艺模拟与分析．化工进展，2003，22(09)：988-991．
[22] 陆恩锡，张慧娟，秦云锋．总体优化提高装置德经济效益．化工科技，2000，8(04)：65-69．
[23] 许学旺．催化裂化吸收稳定装置调查报告．炼油设计，1993，23(02)：14-21．
[24] 张吕鸿，王璐，孙津生．催化裂化吸收-解吸单塔节能流程．石油炼制与化工，2000，31(01)：44-47．
[25] 陆恩锡，张慧娟等．吸收稳定系统工艺流程现状和新流程开发(Ⅰ)—工艺流程现状．炼油设计，2001，31(06)：15-18．
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