镇海炼化氢气网络优化研究
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摘要
由于世界各国都在环境保护方面加强立法，要求炼油厂降低产品硫含量和氮含量，由此促进了加氢工艺的发展，世界范围内的炼油厂对氢气的需求都在不断增加。过去炼油厂的氢气来源以催化重整副产品氢气为主，由于在一系列对于燃料油性质的规定中还要求降低汽油中的芳烃含量，使得重整装置的加工量减少，也就减少了副产氢气的数量，使得炼油厂的氢气更加缺乏。因此炼油厂新建了各种燃料油(气)的制氢装置以满足加氢工艺的需要，但是，制氢装置建设和操作，导致了炼油厂生产成本的增加。针对这一问题，前人采用质量交换网络的方法对炼油厂氢气网络进行了研究，以尽量降低制氢装置的负荷，提出了边际效益夹点分析法，氢气纯度夹点分析法和超结构优化等方法，本文在前人的研究基础上进一步深化了对于氢气网络的研究，论文主要内容包括：
(1)介绍了炼油厂中氢气需求的增长情况以及炼油厂为了应对氢气短缺而采用的各种方法，包括各种制氢方法和各种回收氢气的方法。然后介绍了当前质量交换网络的发展情况以及其主要研究方法。最后介绍了氢气网络集成的研究进展，为进一步的研究提供了坚实的基础。
(2)介绍了炼油厂生产的一般过程和镇海炼化各装置的规模、模型及操作数据。包括加氢精制、加氢裂化、催化重整、制氢和变压吸附装置。其中主要介绍了加氢装置的流程、需要的新氢及产生的高压弛放气、低压弛放气、脱硫化氢干气和瓦斯气的特点及可能的用途。重点分析了加氢装置各种操作条件对反应的影响。
(3)利用夹点法进行了炼油厂氢气网络的优化设计。首先区分了氢源和氢阱的概念，然后通过氢源氢阱复合曲线和氢气剩余曲线在合成网络之前以图形的方式指出了最小氢气使用量。并利用夹点匹配原则合成了新的氢气网络，实现最小氢气使用量的目标。每年可以节约668万元。夹点图还可以帮助选择提纯装置的流股，指出如果改变PSA的原料，可以每年进一步节省2723万元，为企业生产优化提供了理论依据。
浙江大学硕士学位论文
(4)将压力等级的概念引入炼油厂氢气网络的优化方法中。氢气压力等级是重
要的工程应用概念，以前很少有人在网络优化中加以考虑。本文结合某炼油厂扩产
改造时氢气网络的特点，提出了使用超结构方法对氢气网络压力等级进行建模的示
意图和数学模型，并选择了合适的优化算法。通过实例计算，发现镇海炼化氢气网
络在扩建过程中采用3级压力等级方法:50Mpa，100仪[Pa和200MPa，配置3组大
的压缩机即可实现氢气网络的优化运行，采用这种方法，比之对于氢气网络扩建的
原设计可以每年节省3，23千万元的氢气费用，2.3亿元的压缩电费。说明超结构建
模优化对于压力等级选择的有效性。
Environmental policies and legislation are increasing the pressure for change in refining industry. Refinery must reduce sulfur and nitrogen in their products. Hence, hydrogen demand increases to remove them. Simultaneously, to meet the aromatics limits, refineries are reducing the operation load of naphtha reforming, with the result that less hydrogen is being generated. To rebalance supply with demand of hydrogen in refineries, mass integration was introduced to hydrogen networks, marginal profit pinch method, hydrogen purity pinch method and superstructure optimization method are studied by previous researchers, in this thesis hydrogen networks is investigated extensively, and it consists of four parts of contents as follows:
1. The situation of hydrogen supply and demand in refinery is introduced first, and the corresponding methods refinery used to solve it, which include producing more hydrogen and purification method. Then the art-of-state of mass integration was completely reviewed covering through the research scheme to application of integration technology. Finally, the process of hydrogen integration is summarized, which provided solid base for future work.
2. The units which constitute the hydrogen networks in ZRCC are introduced, including the processes, models and operating data of hydrotreater, hydrocracker, reforming, hydrogen plant and pressure swing adsorption, et al. More attention was paid to hydrotreater processes, for example, the influence of operating condition on reaction; the demand of make-up hydrogen, recycle hydrogen; the purity and usage of high pressure purge, low pressure purge, HaS removed gas and fuel gas produced by hydrotreaters.
3. The optimum supply of hydrogen in refinery is studied by pinch technology, which forms the basis of a systematic approach to solving the complex problem of hydrogen system management. Pinch technology is established on the concept of hydrogen sinks and hydrogen sources. Using the data of sinks and sources, hydrogen composite curves and hydrogen surplus curve are plotted. The pinch point means the minimum utility target. In a case study of Zhenhai company, it was shown that the whole cost
can be reduced by 6.68 million per year. The curve can also help to select the flow streams which should be purified. In our example, if the feed streams of PSA is changed, 27.23million can be saved further.
4. Pressure ranking is introduced to synthesize the refinery hydrogen networks. Pressure ranking is used in many aspects in industry, and it can also be used in hydrogen networks because of its simpleness and economics. The hydrogen networks with pressure ranks are modeled and optimized by the superstructure method. The optimization problem was solved by SQP algorithm. In our example, three kinds of pressure ranks are optimum, which are SOMpa, lOOMpa and 200Mpa. Comparing with the designed hydrogen networks, optimized networks with these three pressure ranks can save ?2.23 million per year, and if the compressors are reorganized, ?30 million electric fee can be saved per year further.
(1)介绍了炼油厂中氢气需求的增长情况以及炼油厂为了应对氢气短缺而采用的各种方法，包括各种制氢方法和各种回收氢气的方法。然后介绍了当前质量交换网络的发展情况以及其主要研究方法。最后介绍了氢气网络集成的研究进展，为进一步的研究提供了坚实的基础。
(2)介绍了炼油厂生产的一般过程和镇海炼化各装置的规模、模型及操作数据。包括加氢精制、加氢裂化、催化重整、制氢和变压吸附装置。其中主要介绍了加氢装置的流程、需要的新氢及产生的高压弛放气、低压弛放气、脱硫化氢干气和瓦斯气的特点及可能的用途。重点分析了加氢装置各种操作条件对反应的影响。
(3)利用夹点法进行了炼油厂氢气网络的优化设计。首先区分了氢源和氢阱的概念，然后通过氢源氢阱复合曲线和氢气剩余曲线在合成网络之前以图形的方式指出了最小氢气使用量。并利用夹点匹配原则合成了新的氢气网络，实现最小氢气使用量的目标。每年可以节约668万元。夹点图还可以帮助选择提纯装置的流股，指出如果改变PSA的原料，可以每年进一步节省2723万元，为企业生产优化提供了理论依据。
浙江大学硕士学位论文
(4)将压力等级的概念引入炼油厂氢气网络的优化方法中。氢气压力等级是重
要的工程应用概念，以前很少有人在网络优化中加以考虑。本文结合某炼油厂扩产
改造时氢气网络的特点，提出了使用超结构方法对氢气网络压力等级进行建模的示
意图和数学模型，并选择了合适的优化算法。通过实例计算，发现镇海炼化氢气网
络在扩建过程中采用3级压力等级方法:50Mpa，100仪[Pa和200MPa，配置3组大
的压缩机即可实现氢气网络的优化运行，采用这种方法，比之对于氢气网络扩建的
原设计可以每年节省3，23千万元的氢气费用，2.3亿元的压缩电费。说明超结构建
模优化对于压力等级选择的有效性。
Environmental policies and legislation are increasing the pressure for change in refining industry. Refinery must reduce sulfur and nitrogen in their products. Hence, hydrogen demand increases to remove them. Simultaneously, to meet the aromatics limits, refineries are reducing the operation load of naphtha reforming, with the result that less hydrogen is being generated. To rebalance supply with demand of hydrogen in refineries, mass integration was introduced to hydrogen networks, marginal profit pinch method, hydrogen purity pinch method and superstructure optimization method are studied by previous researchers, in this thesis hydrogen networks is investigated extensively, and it consists of four parts of contents as follows:
1. The situation of hydrogen supply and demand in refinery is introduced first, and the corresponding methods refinery used to solve it, which include producing more hydrogen and purification method. Then the art-of-state of mass integration was completely reviewed covering through the research scheme to application of integration technology. Finally, the process of hydrogen integration is summarized, which provided solid base for future work.
2. The units which constitute the hydrogen networks in ZRCC are introduced, including the processes, models and operating data of hydrotreater, hydrocracker, reforming, hydrogen plant and pressure swing adsorption, et al. More attention was paid to hydrotreater processes, for example, the influence of operating condition on reaction; the demand of make-up hydrogen, recycle hydrogen; the purity and usage of high pressure purge, low pressure purge, HaS removed gas and fuel gas produced by hydrotreaters.
3. The optimum supply of hydrogen in refinery is studied by pinch technology, which forms the basis of a systematic approach to solving the complex problem of hydrogen system management. Pinch technology is established on the concept of hydrogen sinks and hydrogen sources. Using the data of sinks and sources, hydrogen composite curves and hydrogen surplus curve are plotted. The pinch point means the minimum utility target. In a case study of Zhenhai company, it was shown that the whole cost
can be reduced by 6.68 million per year. The curve can also help to select the flow streams which should be purified. In our example, if the feed streams of PSA is changed, 27.23million can be saved further.
4. Pressure ranking is introduced to synthesize the refinery hydrogen networks. Pressure ranking is used in many aspects in industry, and it can also be used in hydrogen networks because of its simpleness and economics. The hydrogen networks with pressure ranks are modeled and optimized by the superstructure method. The optimization problem was solved by SQP algorithm. In our example, three kinds of pressure ranks are optimum, which are SOMpa, lOOMpa and 200Mpa. Comparing with the designed hydrogen networks, optimized networks with these three pressure ranks can save ?2.23 million per year, and if the compressors are reorganized, ?30 million electric fee can be saved per year further.
引文
[1] El-Halwagi M M, Manousiouthakis V. Synthesis of Mass Exchange Networks[J]. AIChE, 1989, 35(8): 1233-1244
[2] El-Halwagi M M, Manousiouthakis V. Simultaneous Synthesis of Mass Exchange and Regeneration Networks[J]. AIChE, 1990, 36(8): 1209-1219
[3] El-Halwagi M M, Srinivas B K. Synthesis of Reactive Mass Exchange Networks [J]. Chem Eng Sci, 1992, 47(8): 2113-2119
[4] Srinivas B K, El-Halwagi M M. Synthesis of Combined Heat and Reactive Mass Exchange Networks [J]. Chem Eng Sci, 1994, 49(13): 2059-2074
[5] El-Halwagi M M, Srinivas B K, Dunn R F. Synthesis of Optimal Heat Induced
Separator Networks[J]. Chem Eng Sci, 1995, 50(1): 81-97
[6] El-Halwagi M M, Harnad A A, Garrison G W. Synthesis of Waster Interception and Allocation Networks[J]. AIChE, 1996, 42(11): 3087-3101
[7] El-Halwagi M M, Spriggs H D. Solve Design Puzzles with Mass Integration[J]. Chem Eng Progress, 1998, 94(8): 25-44
[8] El-Halwagi M M, Spriggs H D. An Integrated Approach to Cost and Energy Effective Pollution Prevention[A]. In: Proceedings of 5th World Congress of Chemical Engineering (San Diego), Ⅲ[C]. New York: AIChE, 1996: 344-349
[9] Parthasarathy G, El-Halwagi M M. Optimum Mass Integration Strategies for Condensation and Allocation of Multi-component VOGs[J]. Chem Eng Sci, 2000, 55(5): 881-895
[10] Wang Y P, Smith R. Wastewater Minimization. Chem Eng Sci, 1994, 49, 19(7): 981-1008
[11] Wang Y P, Smith R. Design of Distributed Effluent Treatment Systems[J]. Chem Eng Sci, 1994, 49(18): 3127-3145
[12] Wang Y P, Smith R. Wastewater Minimization with Flowrate Constraints[J]. Trans ICHEME: Part A, 1995, 73(8): 889-904
[13] Alva-Argaet A, Kokossis A C, Smith R. Wastewater Minimization of Industrial Systems Using an Integrated Approach[J]. Computers and Chemical Engineering, 1998, 22(Suppl): 741-744
[14] Castro P, Motas H, Fernandes M C, et al. Improvement for Mass Exchange Networks Design[J]. Chem Eng Sci, 1999, 54(11): 1649-1665
[15] Savelski M, Bagajewicz M J. Design of Water Utilization System in Process Plants with a Single Contaminant[J]. Waste Management, 2000, 20(8): 659-664
[16] Bagajewicz M J. A Review of Design Procedures for Water Networks in Refineries and Process Plants[J]. Computer and Chemical Engineering, 2000, 24(9 & 10): 659-664
[17] El-Halwagi M M. Manousiouthakis V. Automatic Synthesis of Mass Exchange Networks with Single-Component Target, Chem Eng Sci, 1990, 45(9): 2813-2831
[18] Hallale N, Fraser D M. Capital Coat Targets for Mass Exchange Networks—A
Special Case: Water Minimization. Chem Eng Sci, 1997, 53(2): 293-313
[19] Papalexandri K P, Pistikopoulos E N, Floudas A. Mass Exchange Networks for Waste Minimization: A Simultaneous Approach. Trans Tech, 1994, 72:279-294
[20] El-Halwagi M M. Synthesis of Optimal Reverse-Osmosis Networks for Waste Reduction. AIChE, 1992, 38(8): 1185-1198
[21] Bagajewicz M J, Manousiouthskis V. Mass-Heat Exchange Network Representation of Distillation Network[J]. AIChE, 1992, 38(11): 1769-1800
[22] Bagajewicz M J, Pham R, Manousiouthskis V. On the State Space Approach to Mass/Heat Exchanger Network Design[J]. Chem Eng Sci, 1998, 23(14): 2595-2621
[23] Papaleraddri K P, Pistikopoulos E N. A Multi-period MINLP Model for the Synthesis of Flexible Heat and Mass Exchange Networks[J]. Computers and Chemical Engineering, 1994, 18(11&12): 1125-1139
[24] Lee S, Park S. Synthesis of Mass Exchange Network Using Process Graph Theory[J]. Computers and Chemical Engineering, 1996, 20(suppl): 201-205
[25] Grossmann I E, Westerberg A W. Research Challenges in Process Systems Engineering[J]. AIChE, 2000, 46(9): 1700-1703
[26] Towler G P. Refinery Hydrogen Management: Cost Analysis of Chemical-Integrated Facilities. Ind Eng Chem Res, 1996, 35: 2378-2388
[2] El-Halwagi M M, Manousiouthakis V. Simultaneous Synthesis of Mass Exchange and Regeneration Networks[J]. AIChE, 1990, 36(8): 1209-1219
[3] El-Halwagi M M, Srinivas B K. Synthesis of Reactive Mass Exchange Networks [J]. Chem Eng Sci, 1992, 47(8): 2113-2119
[4] Srinivas B K, El-Halwagi M M. Synthesis of Combined Heat and Reactive Mass Exchange Networks [J]. Chem Eng Sci, 1994, 49(13): 2059-2074
[5] El-Halwagi M M, Srinivas B K, Dunn R F. Synthesis of Optimal Heat Induced
Separator Networks[J]. Chem Eng Sci, 1995, 50(1): 81-97
[6] El-Halwagi M M, Harnad A A, Garrison G W. Synthesis of Waster Interception and Allocation Networks[J]. AIChE, 1996, 42(11): 3087-3101
[7] El-Halwagi M M, Spriggs H D. Solve Design Puzzles with Mass Integration[J]. Chem Eng Progress, 1998, 94(8): 25-44
[8] El-Halwagi M M, Spriggs H D. An Integrated Approach to Cost and Energy Effective Pollution Prevention[A]. In: Proceedings of 5th World Congress of Chemical Engineering (San Diego), Ⅲ[C]. New York: AIChE, 1996: 344-349
[9] Parthasarathy G, El-Halwagi M M. Optimum Mass Integration Strategies for Condensation and Allocation of Multi-component VOGs[J]. Chem Eng Sci, 2000, 55(5): 881-895
[10] Wang Y P, Smith R. Wastewater Minimization. Chem Eng Sci, 1994, 49, 19(7): 981-1008
[11] Wang Y P, Smith R. Design of Distributed Effluent Treatment Systems[J]. Chem Eng Sci, 1994, 49(18): 3127-3145
[12] Wang Y P, Smith R. Wastewater Minimization with Flowrate Constraints[J]. Trans ICHEME: Part A, 1995, 73(8): 889-904
[13] Alva-Argaet A, Kokossis A C, Smith R. Wastewater Minimization of Industrial Systems Using an Integrated Approach[J]. Computers and Chemical Engineering, 1998, 22(Suppl): 741-744
[14] Castro P, Motas H, Fernandes M C, et al. Improvement for Mass Exchange Networks Design[J]. Chem Eng Sci, 1999, 54(11): 1649-1665
[15] Savelski M, Bagajewicz M J. Design of Water Utilization System in Process Plants with a Single Contaminant[J]. Waste Management, 2000, 20(8): 659-664
[16] Bagajewicz M J. A Review of Design Procedures for Water Networks in Refineries and Process Plants[J]. Computer and Chemical Engineering, 2000, 24(9 & 10): 659-664
[17] El-Halwagi M M. Manousiouthakis V. Automatic Synthesis of Mass Exchange Networks with Single-Component Target, Chem Eng Sci, 1990, 45(9): 2813-2831
[18] Hallale N, Fraser D M. Capital Coat Targets for Mass Exchange Networks—A
Special Case: Water Minimization. Chem Eng Sci, 1997, 53(2): 293-313
[19] Papalexandri K P, Pistikopoulos E N, Floudas A. Mass Exchange Networks for Waste Minimization: A Simultaneous Approach. Trans Tech, 1994, 72:279-294
[20] El-Halwagi M M. Synthesis of Optimal Reverse-Osmosis Networks for Waste Reduction. AIChE, 1992, 38(8): 1185-1198
[21] Bagajewicz M J, Manousiouthskis V. Mass-Heat Exchange Network Representation of Distillation Network[J]. AIChE, 1992, 38(11): 1769-1800
[22] Bagajewicz M J, Pham R, Manousiouthskis V. On the State Space Approach to Mass/Heat Exchanger Network Design[J]. Chem Eng Sci, 1998, 23(14): 2595-2621
[23] Papaleraddri K P, Pistikopoulos E N. A Multi-period MINLP Model for the Synthesis of Flexible Heat and Mass Exchange Networks[J]. Computers and Chemical Engineering, 1994, 18(11&12): 1125-1139
[24] Lee S, Park S. Synthesis of Mass Exchange Network Using Process Graph Theory[J]. Computers and Chemical Engineering, 1996, 20(suppl): 201-205
[25] Grossmann I E, Westerberg A W. Research Challenges in Process Systems Engineering[J]. AIChE, 2000, 46(9): 1700-1703
[26] Towler G P. Refinery Hydrogen Management: Cost Analysis of Chemical-Integrated Facilities. Ind Eng Chem Res, 1996, 35: 2378-2388