Heat Integration of Two Low-Temperature Processes: Natural Gas Liquefaction and Air Separation Unit

Document Type : Research paper

Authors

1 School of Chemical Engineering. College of Engineering, University of Tehran

2 School of chemical Engineering-College of Engineering-University of Tehran

3 School of Chemical Engineering-University of Tehran

4 Institute of pertrolum Engineering -University of Tehran

Abstract

This research aims to present a new integrated design for Natural Gas Liquefaction and two-column Air Separation Units, each of them with a capacity of 60,000 kg/h. First, each of these two selected units was simulated and optimized using Genetic Algorithm with the aim of reducing total annualized costs. Then, the streams were thermally investigated and after identifying the streams participating in the process heat transfer area, the processes were integrated. The results of the sensitivity analysis of the integrated process indicated that by increasing the outlet pressure of the C-5 compressor, increasing the outlet pressure of the VLV-5 expansion valve and increasing the flow intensity of isopentane refrigerant, the annual cost decreases and by increasing the flowrate of other refrigerant components, the annual cost increases. In the next step, the integrated process was optimized using MATLAB software. The results showed that by integrating these two processes, the amount of the power consumed in the processes increases from 46.6 to 48.5 MW. This increase in power consumption increases the operating costs of the compressors by 4%, capital costs reduce from 246.2 to $218 million, which is reduced by approximately 11%, and the total annualized cost was reduced by
$1.2 million /y.

Keywords

Main Subjects

References

[1] H. Tuo, and Y. Li, (2011) “Exergy analysis of combined cycle of air separation and natural gas liquefaction”, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, 5, 77-83.
 
[2] A. Vatani, M. Mehrpooya, and A. Palizdar, (2014) “Advanced exergetic analysis of five natural gas liquefaction processes”, Energy Conversion and Management, 78, 720-737.
 
[3] M. Mehrpooya, M. M. M. Sharifzadeh, and M. A. Rosen, (2015) “Optimum design and exergy analysis of a novel cryogenic air separation process with LNG (liquefied natural gas) cold energy utilization”, Energy, 90, 2047-2069.
 
[4] T. Morosuk, S. Tesch, A. Hiemann, G. Tsatsaronis, and N. B. Omar (2015) “Evaluation of the PRICO liquefaction process using exergy-based methods”, Journal of Natural Gas Science and Engineering, 27, 23-31.
 
[5] A. Ebrahimi, M. Meratizaman, H.A. Reyhani, O. Pourali, and M. Amidpour (2015) “Energetic, exergetic and economic assessment of oxygen production from two columns cryogenic air separation unit”, Energy, 90, 1298-1316.
 
[6] T. He, M. Ning, L. Zuming, M. Abdul Qyyum, L. Moonyong, and M. P. Ashak, (2020) “Impact of mixed refrigerant selection on energy and exergy performance of natural gas liquefaction processes”, Energy, 199, 117378.
 
[7] A. Ghazikhani, A. B. Rahimi, and M. Mamourian (2020) “Exergy analysis of an industrial air separation unit for liquefied natural gas production”, International Journal of Exergy, 31, 172-185.
 
[8] س. فرامرزی، س. م. موسوی نائینیان، م. مافی و ر. قاسمی اصل (1401) "اصلاح و بهینه‌سازی چرخه مایع‌ساز هیدروژن مجهز به سیستم تبخیرکنندۀ گاز طبیعی مایع" نشریه مهندسی مکانیک دانشگاه تبریز، 52، 3، 11-20.
 
[9] و. یاری‌جانی، ن. طاهونی، م. ح. پنجه‌شاهی، م. عباسی (1401) "طراحی یک فرآیند یکپارچه مایع‏سازی گاز طبیعی / جداسازی هوا" پنجمین کنفرانس علوم و مهندسی جداسازی، زاهدان، ایران.
 
[10] S. Nikkho, M. Abbasi, J. Zahirifar, M. Saedi and A. Vatani, (2020) “Energy and exergy investigation of two modified single mixed refrigerant processes for natural gas liquefaction”, Computers and Chemical Engineering, 140, 106854.
 
[11] S. Rahimi, M. Meratizaman, S. Monadizadeh, and M. Amidpour (2014) “Techno-economic analysis of wind turbine–PEM (polymer electrolyte membrane) fuel cell hybrid system in standalone area”, Energy, 67, 381-396.
 
[12] G. Towler, and R. Sinnott (2012) Chemical Engineering Design: Principles, Practice and Economics of Plant and Process Design, Elsevier, 2nd edition.
 
[13] R. Smith (2016) Chemical Engineering Design and Integration, John Wiley & Sons, 2nd edtion.
 
[14] W. D. Seider, D. J. Seader, and D.R. Lewin (2009) Product & Process Design Principles: Synthesis, Analysis and Evaluation, John Wiley & Sons, 3rd edition.
 
[15] Z Wei, B. Zhang, S. Wu, Q. Chen, and G. Tsatsaronis (2012) “Energy-use analysis and evaluation of distillation systems through avoidable exergy destruction and investment costs”, Energy, 42(1), 424
Journal of Separation Science and Engineering
Volume 14, Issue 2
April 2023
Pages 67-81

Files

Share

How to cite

Statistics