Simulation, integration, and economic analysis of gas-to-liquid processes

• Main Author: Bao, Buping
• Other Authors: El-Halwagi, M. Mahmoud
• Format: Others
• Language: en_US
• Published: 2010
• Subjects: GTL; FT
• Online Access: http://hdl.handle.net/1969.1/ETD-TAMU-3131; http://hdl.handle.net/1969.1/ETD-TAMU-3131

Gas-to-liquid (GTL) process involves the chemical conversion of natural gas (or other gas sources) into synthetic crude that can be upgraded and separated into different useful hydrocarbon fractions including liquid transportation fuels. A leading GTL technology is the Fischer Tropsch process. The objective of this work is to provide a techno-economic analysis of the GTL process and to identify optimization and integration opportunities for cost saving and reduction of energy usage and environmental impact. First, a basecase flowsheet is synthesized to include the key processing steps of the plant. Then, computer-aided process simulation is carried out to determine the key mass and energy flows, performance criteria, and equipment specifications. Next, energy and mass integration studies are performed to address the following items: (a) heating and cooling utilities, (b) combined heat and power (process cogeneration), (c) management of process water, (c) optimization of tail-gas allocation, and (d) recovery of catalystsupporting hydrocarbon solvents. Finally, an economic analysis is undertaken to determine the plant capacity needed to achieve the break-even point and to estimate the return on investment for the base-case study. After integration, 884 million $/yr is saved from heat integration, 246 million $/yr from heat cogeneration, and 22 million $/yr from water management. Based on 128,000 barrels per day (BPD) of products, at least 68,000 BPD capacity is needed to keep the process profitable, with the return on investment (ROI) of 5.1%. Compared to 8 $/1000 SCF natural gas, 5 $/1000 SCF price can increase the ROI to 16.2%.