Environmental study of waste energy recovery by using exergy and economic analysis in a fluid catalytic cracking unit

Document Type: Research Paper

Authors

1 Research and Development of Energy and Environment Pardise, Research Institute of Petroleum Industry, Tehran, Iran

2 Petroleum University of Technology, Ahwaz Faculty of Petroleum, Ahwaz, Iran

3 Faculty members of Research Institute of Petroleum Industry (RIPI), Tehran, Iran

Abstract

An increase in fossil fuel consumption has significantly increased the concentration of greenhouse gases (GHGs). Waste energy recovery can reduce GHGs by reducing fossil fuel consumption. In the FCC unit in refineries, the catalyst is continuously regenerated by burning off the deposited coke with air and a large flux of waste gas with high temperature is generated which is vented into the atmosphere. The purpose of this study was to investigate the effect of waste heat/pressure recovery of the waste gas on the reduction of GHGs and air pollutant emissions. Based on this objective, exergy and economic analysis were carried out for two scenarios (S-1 and S-2). The S-1 scenario involved the installation of a Heat Recovery Steam Generator (HRSG), while S-2 applied the simultaneous usage of HRSG and a turbo-expander to evaluate electricity production using waste gas pressure. The exergy of waste gas was formulated and an in-house code was developed for solving the equations via a trial and error method. The results showed that exergy loss of the waste gas was higher than 660 MW and it was possible to recover about 64 MW and 75 MW in the S-1 and S-2, respectively. The amount of steam and the electrical energy produced were found to be about 88 ton/h and 8323 MWh/month, respectively. The results also showed that S-1 can reduce 72227 tCO2e of GHGs and 327 ton of air pollutant and S-2 can reduce 143464 tCO2e of GHGs and 649 ton of air pollutant annually. The economic indexes were evaluated and the results indicated that the internal rates of return (IRR) were found to be 33.18% and 36.76% for S-1 and S-2, respectively. This showed that the two scenarios were economically feasible, but from an environmental, economic and energy recovery standpoint, S-2 was the best scenario and the economic analysis on S-2 certified that there was no economic risk.

Keywords

Main Subjects


[1] Singh, S., Jain, S., Venkateswaran, P. S., Tiwari, A. K., Nouni, M. R., Pandey, J. K., Goel, S. (2015). Hydrogen: a sustainable fuel for future of the transport sector. Renewable and sustainable energy reviews, 51, 623-633

[2] Rahman, F. A., Aziz, M. M. A., Saidur, R., Bakar, W. A. W. A., Hainin, M. R., Putrajaya, R., Hassan, N. A. (2017). Pollution to solution: Capture and sequestration of carbon dioxide (CO2) and its utilization as a renewable energy source for a sustainable future. Renewable and sustainable energy reviews, 71, 112-126.

[3] Center, M. P. (2012). National low carbon fuel standard, Carnegie Mellon University.

[4] Wennersten, R., Sun, Q., Li, H. (2015). The future potential for Carbon Capture and Storage in climate change mitigation–an overview from perspectives of technology, economy and risk. Journal of cleaner production, 103, 724-736.

[5] He, X., Fu, C., Hägg, M. B. (2015). Membrane system design and process feasibility analysis for CO2 capture from flue gas with a fixed-site-carrier membrane. Chemical engineering journal, 268, 1-9.

[6] Chen, L., Sasaki, H., Watanabe, T., Okajima, J., Komiya, A., Maruyama, S. (2017). Production strategy for oceanic methane hydrate extraction and power generation with carbon capture and Storage (CCS). Energy, 126, 256-272.

[7] Hansson, A., Bryngelsson, M. (2009). Expert opinions on carbon dioxide capture and storage—a framing of uncertainties and possibilities. Energy policy, 37(6), 2273-2282.

[8] Matzen, M., Demirel, Y. (2016). Methanol and dimethyl ether from renewable hydrogen and carbon dioxide: Alternative fuels production and life-cycle assessment. Journal of cleaner production, 139, 1068-1077.

[9] Matzen, M., Alhajji, M., Demirel, Y. (2015). Chemical storage of wind energy by renewable methanol production: Feasibility analysis using a multi-criteria decision matrix. Energy, 93, 343-353.

[10] Luthra, S., Kumar, S., Garg, D., Haleem, A. (2015). Barriers to renewable/sustainable energy technologies adoption: Indian perspective. Renewable and sustainable energy reviews, 41, 762-776.

[12] Elum, Z. A., Momodu, A. S. (2017). Climate change mitigation and renewable energy for sustainable development in Nigeria: A discourse approach. Renewable and sustainable energy reviews, 76, 72-80.

[13] Kandiyoti, R., Herod, A., Bartle, K. D., Morgan, T. J. (2016). Solid fuels and heavy hydrocarbon liquids: thermal characterization and analysis. Elsevier.

[14] Morrow, W. R., Marano, J., Hasanbeigi, A., Masanet, E., Sathaye, J. (2015). Efficiency improvement and CO2 emission reduction potentials in the United States petroleum refining industry. Energy, 93, 95-105.

[15] PoĹživil, J. (2004). Use of expansion turbines in natural gas pressure reduction stations. Acta montanistica slovaca, 9(3), 258-260.

[16] Farzaneh-Gord, M., Maghrebi, M. J. (2009). Exergy of natural gas flow in Iran's natural gas fields. International journal of exergy, 6(1), 131-142.

[17] Maddaloni, J. D., Rowe, A. M. (2007). Natural gas exergy recovery powering distributed hydrogen production. International journal of hydrogen energy, 2(5), 557-566.

[18] Arabkoohsar, A., Farzaneh-Gord, M., Deymi-DashteBayaz, M., Machado, L., Koury, R. N. N. (2015). A new design for natural gas pressure reduction points by employing a turbo expander and a solar heating set. Renewable energy, 81, 239-250.

[19] Sharma, M., Singh, O. (2016). Exergy analysis of dual pressure HRSG for different dead states and varying steam generation states in gas/steam combined cycle power plant. Applied thermal engineering, 93, 614-622.

[20] Li, J., Wang, K., Cheng, L. (2017). Experiment and optimization of a new kind once-through heat recovery steam generator (HRSG) based on analysis of exergy and economy. Applied thermal engineering, 120, 402-415.

[21] Smith, J. M., Van Ness, H., Abbott, M. (2005). Introduction to chemical engineering thermodynamics, The McGraw-Hill Chemical Engineering Series, New York, USA.

[22] API, (2014). Compendium of Greenhouse Gas Emissions Methodologies for the Oil and Natural Gas Industry.

[23] Peters, M. S., Timmerhaus, K. D., West, R. E., Timmerhaus, K., West, R. (1968). Plant design and economics for chemical engineers (Vol. 4). New York: McGraw-Hill.

[24] Lozowski, D., Ondrey, G., Jenkins, S., Bailey, M. P. (2012). Chemical engineering plant cost index (CEPCI). Chemical engineering journal, 119, 84.

[26] Bloch, H. P., Soares, C. (2001). Turboexpanders and process applications. Gulf professional publishing.