G4 Insight's proprietary process PyroCatalytic Hydrogenation (PCH) uses fast pyrolysis rather than gasification of the biomass to generate a vapor from the solid phase. This fundamental difference enables a low temperature thermochemical process (Figure 1) consisting of the following components:
Forestry biomass composition may be generally represented as C6H9O4. The hydropyrolysis process vaporizes the biomass into volatile gases and aerosols. Tar formation is eliminated through G4 proprietary processes. Catalytic formation of methane involves a variety of reactions which hydrogenate the pyrolysis gases to form methane and water:
C6H9O4 + 11.5 H2 → 6 CH4 + 4 H2
However, hydropyrolysis always produces a portion of solid char so that not all of the carbon is transferred from wood to methane. The G4 process utilizes this char to generate the heat required for making hydrogen with the reformer. No external hydrogen supply is required in the PCH process. The thermal energy of the reformer heating and process streams are utilized to energize the heating media used in the pyrolysis process and the biomass drying. Separation and purification of a high grade methane mixture is performed by a proprietary pressure swing adsorption process and yields methane purity levels over 98%.
Net energy conversion efficiency (HHV basis) from biomass to methane is nominally greater than 70%. The G4 RNG product will meet all natural gas pipeline specifications around the world. The gas is renewable and sustainable, suitable for renewable power generation and can be classified as a Super-Ultra-Low-Carbon transportation fuel (California).
G4 has multiple patents issued in the US and in China to date.
The G4 technology is in the process demonstration phase and the G4 Process Demonstration Unit has achieved 88% to 100% of commercial target performance for core processes.
The California Energy Commission selected G4 for a $2.5 million mobile demonstration project. The project successfully demonstrated the production of transportation grade RNG from local forestry residue and subsequent use in an unmodified CNG vehicle in Placer County, California.