Modular Liquid Fuel and Power Co-Generation System for Shale Gas Upgrading

Keywords

“Wet” components of shale gas, i.e. hydrocarbons that are heavier than methane, are imposing new challenges to natural gas producers and service companies. Ethane can represent up to 20 vol.% of shale gas, far exceeding the maximum of 10 vol.% ethane allowed for “pipeline-quality” natural gas. Although a fraction of ethane can be transported with existing infrastructure, a significant portion of ethane, especially those in stranded regions, becomes a significant liability for gas producers. Over 210 million barrels (liquid equivalent) of ethane is rejected (e.g. reinjected into the gas wells) each year in the lower 48 States. For the transportable portion of ethane, the surge in supply and the lack of facilities for ethane utilization contributed to a 5-fold decrease in ethane spot prices over the past 8 years.

Therefore, new technologies to convert: (i) negative value ethane in stranded gas wells; and/or (ii) low cost ethane in centralized locations can create significant value. Additionally, shale gas production facilities consume significant electric power and water, which can be prohibitively expensive in remote locations. Therefore, distributed ethane-upgrading systems that can convert ethane into easily transportable liquid fuels while co-producing water and electricity are highly desirable. Led by NC State Professor Fanxing Li, this project aims to develop a modular system for distributed co-generation of liquid fuel, power and water.

Technologies that can effectively convert cheap, stranded ethane into transportation fuels are of significant value to US shale gas producers and chemical companies. Unfortunately, such technologies have not been developed to date, due mainly to the various intrinsic limitations of commercial ethane steam cracking and conventional technologies. This project goal is to enable economical production of synthetic gasoline from ethane that is particularly useful for producers in geographically isolated shale-gas fields, where transportation of ethane over large distances are prohibitively expensive. Dr. Li’s work addresses the critical limitations of existing approaches and allow efficient production of low-cost fuels from domestic resources.