(150a) Natural Gas Based Hydrogen Production with Ethylene and Formic Acid Co-Production

The air quality in major metropolitan areas follows a deterioration trend, chiefly due to the large population of small and medium transportation vehicles. Given this conditions, scientists and engineers around the world are committed to use all tools available to reduce and finally stop this path to environmental destruction. It has previously proposed the use of hydrogen as an effective energy carrier for small and medium vehicles. This option has strengthened with the advancement in the development of fuel cells manufacturing and hydrogen storage. This growth is also reflected in the development of new hydrogen production designs that effectively surpass existing technologies. Several options exist for hydrogen production; one of the most explored has been the reforming of natural gas given that methane contains potentially two hydrogen gas molecules. The main problem with conventional natural gas reformers is the emission of carbon dioxide, a greenhouse whose emissions have led to an increase in its concentration in the atmosphere. Transforming carbon dioxide into a useful product prevents its emission into the atmosphere, however an inadequate process design might largely increase the cost of producing hydrogen, making it uncompetitive with gasoline.

In this work we present a hydrogen production process in which hydrogen and ethylene are co-generated, while no carbon dioxide is emitted. Natural gas undergoes oxidative coupling to produce ethylene and water. This mixture is separated and the water produced undergoes reforming along with natural gas to produce a hydrogen containing mixture. Hydrogen is purified through a pressure swing adsoption, a fraction of which goes through a series of compressors and becomes the final product. The rest of it is sent to a formic acid production system in which reacts with carbon dioxide producing formic acid. The overall process goes through heat and power integration techniques that allow the maximum utilization of energy in favor of hydrogen production, maintaining a self-powered plant and reducing the carbon dioxide emissions to zero. We show that there exists an optimal themodynamical and operational point for the operation of the plant.