(218d) Energetically Self-Sufficient Coproduction of Hydrogen and Formic Acid

The use of hydrogen has been proposed as a solution to the air quality deterioration in metropolitan areas and 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. To technologically advance this alternative, new hydrogen production designs are to be developed. 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 comparison between three different hydrogen and formic acid coproduction process. The first design provides a baseline for the production of hydrogen with recovery of carbon dioxide downstream of the steam reforming process, where the carbon recovered in this way is utilized to produce formic acid. The second design recovers the carbon dioxide released at the source of energy generation, thus producing a larger amount of formic acid and eliminating carbon emissions to zero. A third design implements the commercially established formic acid production process into a design including hydrogen production. Given the structure and feedstock of this formic acid plant, the hydrogen production can no longer by carried out by a steam reforming process but rather from a combination of dry reforming and water gas shift. These three processes go through heat and power integration techniques that allow the maximum utilization of energy in favor of hydrogen production, maintaining a self-powered plant and maintaining the carbon dioxide emissions at zero. We show that there exists an optimal themodynamical and operational point for the operation of these plants.