TRI's Pulse-enhanced Gasification Process
Gasification is a thermochemical process that converts any carbon-containing material into a synthesis gas (“syngas”) that can be used as a feedstock to make value-added biofuels and biochemicals, as a fuel for combined cycle power generation, or as a replacement for fossil fuels including natural gas and fuel oil.
The biomass feedstock reacts in the gasifier with steam and oxygen in a reducing (oxygen-starved) atmosphere to produce syngas made up primarily of hydrogen, carbon monoxide, carbon dioxide and smaller quantities of methane and other hydrocarbons.
This indirect heating method utilizes modular pulse combustion heaters in a steam-driven bubbling fluid bed vessel. Heat required to achieve reformer operating temperature and for the endothermic steam-reforming reactions is supplied by the pulsed heat exchangers immersed in the fluidized bed. The heat exchangers consist of bundles of pulsed heater resonance tubes. A portion of the syngas generated in the reformer is burned in the pulsed heaters to supply the necessary heat, thereby making the steam reformer energy self-sufficient, operating on its own fuel. Pulsations in the resonance tubes produce a gas-side heat transfer coefficient which is several times greater than a conventional fire-tube heater. This efficient heat transfer reduces the size and cost of the heat exchangers and reformer vessel. The hot combustion gases leaving the pulsed heaters are sent to a heat recovery steam generator (HRSG) to generate steam. The hot syngas from the reformer is passed through cyclones to remove particulate matter, cooled in a second HRSG, and then quenched and scrubbed. The clean syngas can then be used to produce green fuels, combined cycle energy or replace fossil fuels.
The flash animations on the "Technology" page explain how the pulse combustion heater and the steam reformer work.