(645b) Integrated Process Development and Economic Evaluations for an Optimum Gas Processing Plant

Heavy hydrocarbon removal is one of the processes in natural gas processing plants for reducing heating value and to control hydrocarbon dew point of sales gas. Conventional technologies include Joule Thomson expansion, turboexpansion, mechanical refrigeration, membrane separation and supersonic centrifugal separation. The aim of this work is to develop and optimize an integrated process for natural gas plant and natural gas liquid (NGL) productions. The system is based on acid gas removal unit, simultaneous absorption of heavy hydrocarbons and water from natural gas using a mixture of triethylene glycol (TEG), NGL recovery and sales gas compression. Natural gas processes are modelled and simulated within Aspen HYSYS simulator with a common set of operating criteria and thermodynamic parameters for the absorption process, based on field data. The reboiler temperature of TEG regenerator and then the hot stripping gas flowrate, have been studied for their response to changes in the regenerated TEG concentration, dew point of sale gases, TEG losses (make-up) and reboiler duty. Finally, Aspen process economic analyzer program is used to calculate the expected capital expenditures of the plant. Process description, operating conditions, equipment sizing, recovery efficiency and limitations for the new absorption process are presented. This integrated technology has an equipment sizing, investment and operating cost, and energy consumption lower than commercial technologies available nowadays. Results indicate an increase in hydrocarbon absorption efficiency. Energy consumption is lower than other processes, while the capital cost and operating cost are also lower.