Simulation and Optimization of Syngas Generation Process (GTL Stage I) using ASPEN Hysys

Abstract

The process of gas to liquid (GTL) conversion has been divided into three sections (section I: natural gas treatment and syngas production; section II: is Fischer Tropsch Synthesis sections (Main Reactors) and Stage III: Upgrading and treatment section).

This work is mainly for Stage I. whereby Natural gas dehydration unit is simulated using Tri-ethylene Glycol to dehydrate the natural gas which includes (Free Water Knockout Drum (FWKD), Absorber and Distillation). Sweetening Unit using DEA has been used to reduce the acid gases using an Amine absorber and Regenerator. A synthetic gas generation has been modeled using a pre-reformer reactor to convert all the non-methane hydrocarbon to syngas to avoid thermal decomposition of heavier hydrocarbons. Auto-Thermal Reformer (ATR) to produce syngas (a mixture of hydrogen and carbon monoxide). The energy produced from this section has been used to heat the upcoming feeds, and generate low-pressure steam which used for steam reforming and that results in saving cost and energy. The ratio of hydrogen to carbon monoxide has been optimized within the required range to enter the Fischer Tropsch reactor using the recycles feed, steam, and Oxygen flow rates. The temperature of the ATR outlet was controlled to act within the limit (avoiding thermal decomposition temperature) using steam and oxygen flow rate. The results were compared (in terms of conversion and product quantity) to the published values and it is found to be within the range. Material balance has been reported for the simulated process. Sensitivity analysis has been carried out by evaluating different case studies (14 case studies) which include parameters such as Syngas temperature, H₂: CO ratio, Conversion, Reactor Temperature, and Pressure, recycle ratio and Productivity of Reactor in order to understand the effects of various parameters on the simulation.