Journal of Gas Technology

Aspen Plus Simulation of Power Generation Using Turboexpanders in Natural Gas Pressure Reduction Stations

Document Type : Original Article

Authors

1 Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

2 Chemical & Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran

Abstract

This paper investigates the economic feasibility of installing a turboexpander in parallel with the throttling valve of a city gate station for the purpose of distributed electricity generation through exergy recovery from pressurized natural gas. The preheating requirements for preventing hydrate formation due to pressure reduction are provided by the combustion of a small fraction of the outlet natural gas stream. As a case study, the simulation of Tehran No.2 City Gate Station demonstrates an exergy loss of more than 36.5 million kWh per year for the present throttling valves. Thermo-economic analyses gives the optimum operating conditions for electricity generation through a turboexpander. Optimization of preheating temperature leads to an exergy recovery of >60%, cost to generate electricity of <$0.04/kWh, and discounted payback period of around ~4 years. Simulation results can be used for designing an automatic preheating temperature control system to optimize exergy recovery via turboexpander under the variable operating conditions of a pressure reduction station.

Keywords

Main Subjects

Article Title [Persian]

شبیه سازی تولید توان الکتریکی با استفاده از توربین‌های انبساطی در ایستگاه‌های تقلیل فشار گاز طبیعی با استفاده از نرم افزار Aspen Plus

Authors [Persian]

  • بیژن حجازی 1
  • فتح ا... فرهادی 2

1 استادیار گروه مهندسی شیمی، دانشکده مهندسی، دانشگاه فردوسی مشهد، مشهد، ایران

2 استاد دانشکده مهندسی شیمی و نفت، دانشگاه صنعتی شریف، تهران، ایران

Abstract [Persian]

این مقاله امکان سنجی اقتصادی تولید برق پراکنده از بازیافت اکسرژی جریان گاز طبیعی تحت فشار از طریق نصب توربین انبساطی به موازات شیر فشار شکن در ایستگاه تقلیل فشار شهری را مورد مطالعه قرار می دهد. احتیاجات پیش گرمایشی مورد نیاز برای جلوگیری از تشکیل هیدرات بر اثر افت فشار توسط احتراق کسر کوچکی از جریان گاز طبیعی خروجی تامین می گردد. به عنوان مطالعه موردی، شبیه سازی ایستگاه دروازه شهری شماره ۲ شهر تهران بیانگر اتلاف اکسرژی بیش از ۳۶/۵ میلیون کیلووات ساعت در سال توسط شیرهای فشار شکن موجود است. آنالیزهای ترمودینامیکی و اقتصادی، شرایط عملیاتی بهینه برای تولید برق توسط توربین انبساطی را بدست می دهند. بهینه سازی دمای پیش گرمایش منجر به بیش از ۶۰ درصد بازیافت اکسرژی، هزینه برق تولیدی کمتر از 0.04 دلار بر کیلووات ساعت و زمان بازگشت سرمایه حدود 4 سال می گردد. از نتایج شبیه سازی ها می توان برای طراحی سیستم کنترل خودکار دمای پیش گرمایش به منظور بهینه سازی بازیافت اکسرژی توسط توربین انبساطی تحت شرایط عملیاتی متغیر ایستگاه تقلیل فشار گاز استفاده نمود. 

Keywords [Persian]

  • گاز طبیعی
  • ایستگاه تقلیل فشار
  • توربین انبساطی
  • شبیه سازی فرایند
  1. Lehman B., Worrell E., 2001. Electricity production from natural gas pressure recovery using expansion turbines. Proceedings of 2001 ACEEE Summer Study Energy Efficiency Industry. Tarrytown, NY, USA.
  2. Poživil, J., 2004. Use of expansion turbines in natural gas pressure reduction stations. Acta Montanistica Slovaca 3 (9), 258-260.
  3. Jedynak A., 2005. Electricity production in gas pressure reduction systems (in Polish). Proceedings of 3rd International Conference Energy from Gas. Gliwice.
  4. Maddaloni, J.D., Rowe, A.M., 2007. Natural gas exergy recovery powering distributed hydrogen production. International Journal of Hydrogen Energy 32, 557-566.
  5. Ardali, E.K., Hybatian, E., 2009. Energy regeneration in natural gas pressure reduction stations by use of gas turboexpander: Evaluation of available potential in Iran. Proceedings of 24th World Gas Conference. Buenos Aires, Argentina.
  6. Kostowski, W.J., 2010. The possibility of energy generation within the conventional natural gas transport system. Strojarstvo 52 (4), 429-440.
  7. Taheri-seresht, R., Jalalabadi, H.K., Rashidian, B., 2010. Retrofit of Tehran City Gate Station (C.G.S.No.2) by using turboexpander. Proceedings of ASME 2010 Power Conference. Chicago, Illinois, USA.
  8. Sanaye, S., Mohammadi-nasab, A., 2010. Modeling and optimization of a natural gas pressure reduction station to produce electricity using genetic algorithm. Proceedings of 6th International Conference on Energy, Environment, Sustainable Development and Landscaping. Romania.
  9. Taleshian, M., Rastegar, H., Askarian-abyaneh, H., 2012. Modeling and power quality improvement of grid connected induction generators driven by turbo-expanders. International Journal of Energy Engineering 2 (4), 131-137.
  10. Khanmohammadi, S., Ahmadi, P., Mirzei, D., 2014. Thermodynamic modeling and optimization of a novel integrated system to recover energy from a gas pressure reduction station. Proceedings of the 13th International Conference of Clean Energy. Istanbul, Turkey.
  11. Rahman, M.M., 2010. Power generation from pressure reduction in the natural gas supply chain in Bangladesh. Journal of Mechanical Engineering 41 (2), 89-95.
  12. Howard, C.R., 2009. Hybrid turboexpander and fuel cell system for power recovery at natural gas pressure reduction stations. M.Sc. Thesis, Queen’s University, Canada.
  13. Farzaneh-gord, M., Sadi, M., 2008. Enhancing energy output in Iran’s natural gas pressure drop stations by cogeneration. Journal of the Energy Institute 81 (4), 191-196.
  14. Kostowski, W.J., Uson, S., 2013. Comparative evaluation of a natural gas expansion plant integrated with an IC engine and an organic Rankine cycle. Energy Conversion and Management 75, 509-516.
  15. He, T., Ju, Y., 2013. Design and optimization of natural gas liquefaction process by utilizing gas pipeline pressure energy. Applied Thermal Engineering 57 (1), 1-6.
  16. Khalili, E., Hoseinalipour, M., Heybatian E., 2011. Efficiency and heat losses of indirect water bath heater installed in natural gas pressure reduction station: Evaluating a case study in Iran. Proceedings of 8th National Energy Congress. Shahrekord, Iran.
  17. Azizi, S.H., Rashidmardani, A., Andalibi, M.R., 2014. Study of preheating natural gas in gas pressure reduction station by the flue gas of indirect water bath heater. International Journal of Science and Engineering Investigations 3 (27), 17-22.
  18. Farzaneh-gord, M., Arabkoohsar, A., Deymidasht-bayaz, M., Farzaneh-kord, V., 2011. Feasibility of accompanying uncontrolled linear heater with solar system in natural gas pressure drop stations. Energy 41 (1), 420-428.
  19. Ashouri, E., Veysi, F., Shojaeizadeh, E., Asadi, M., 2014. The minimum gas temperature at the inlet of regulators in natural gas pressure reduction stations (CGS) for energy saving in water bath heaters. Journal of Natural Gas Science and Engineering 21, 230-240.
  20. Szargut, J., Szczygiel, I., 2009. Utilization of the cryogenic exergy of liquid natural gas (LNG) for the production of electricity. Energy 7 (34), 827- 837.
  21. Peters, M.S., Timmerhaus, K.D., West, R.E., 2003. Plant Design and Economics for Chemical Engineers (5th ed.). McGraw-Hill Chemical Engineering Series, Boston.
  22. Douglas, J.M., 1988. Conceptual Design of Chemical Processes. McGraw-Hill, London.
  23. Carlson, E.C., 1996. Don’t Gamble with Physical Properties for Simulations, Aspen Technology, Inc.
Journal of Gas Technology
Volume 6, Issue 1 - Serial Number 6
September 2021
Pages 14-29