Split-Flow Integrated Small-Scale LNG Production Process with Cryogenic Carbon Dioxide Capture
Date
2020-09-28
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This thesis addressed three challenges facing the processing of natural gas. First, energy is usually required to produce energy, but it takes more energy to produce liquified natural gas (LNG) than other fossil fuels. In other words, LNG production is a very energy-intensive process, which makes it less competitive. Second, many cryogenic NGL-recovery facilities have been working under full capacity due to low natural gas prices and limited accessible new markets. The last challenge concerns the classic aqueous alkanolamine-based sweetening process, which involves saturating gas with water and restricting the LNG production temperature to be begin from ambient temperature and needs a finishing process to handle the produced acid gas.With a view to address these challenges, first, a novel integrated small-scale LNG process concept was developed that can not only maximize the economic value of NGL recovery facilities but also produce LNG via a more efficient and greener process. This was achieved through comprehensive process simulations, optimizations, and heat integration studies. These studies were performed using the Aspen HYSYS simulation package to find an efficient integrated LNG production process that can use available sources of heating/cooling in a cryogenic NGL-recovery facility without sacrificing the NGL production yield. In the development process, it was determined that an adsorption process (nonsolvent) can remove CO2 at cryogenic temperatures and treat natural gas with the aim of meeting the LNG specification (CO2=50 ppm). This led me to the development of the “split-flow integrated small-scale LNG production process (SFI-LNG)”, which has two main pillars—the cryogenic CO2 removal process and the semi-C3-MR liquefaction process.Second, to validate the cryogenic removal of CO2, zeolite-based adsorbents were synthesized and characterized before they were successfully tested under cryogenic conditions.Third, a bench-scale experimental setup was designed and constructed to prove the concept of cryogenic CO2 removal. Finally, the concept was proven at the bench scale.The principle of cryogenic CO2 removal is based on the selective adsorption of CO2 by a Faujasite (FAU)-based adsorbent under cryogenic conditions, which exhibits a high adsorption rate with great recyclability. In addition, there is no need for a finishing process to deal with acid gas, as highly pure CO2 can be produced as a byproduct.
Description
Keywords
Small-Scale LNG, Carbon Dioxide Capture, Cryogenic Process, NGL Recovery
Citation
Ostovar, A. (2020). Split-Flow Integrated Small-Scale LNG Production Process with Cryogenic Carbon Dioxide Capture (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.