The Integral Gasification Thermo-Chemical (IGTC) electric plant is the subject of a pending patent, which describes an alternate ”third way” primary heat source to replace problematic solar and nuclear heating, the main impediment to thermochemical hydrogen. The IGTC recovers heat from recycled char in a gasifier to a thermochemical reactor to deliver hydrogen and some syngas to fire a station gas turbine-generator and provide liquefied methane for export and vehicle use. Water splitting temperature by recovered gasifier heat is sufficient to drive several candidate thermochemical cycles, while carbon emissions due to fuel synthesis and combustion of remaining syngas are nearly eliminated. Conventional gasification of wood and coal by Integrated Gasification Combined Cycle (IGCC), is already a commercial and expanding technology and there is potential to upgrade many of these plants to the proposed IGTC concept.
Gasifier outlet temperature of ~ 1200–1500 oC at ~ 60 bar is well suited for sulfur cycles at 850 oC and a manganese oxide cycle at 1100-1300 oC cycle. Recovery of ~ 40 % gasifier waste heat to these cycles delivers hydrogen and syngas with twice the heating potential of normal syngas output and very low carbon dioxide for capture. The hybrid sulfur and sulfur-iodine cycles are under advanced development by the Department of Energy and a manganese oxide cycle has recently been proposed as a non-volatile alternative. The thermochemical reactor replaces an inefficient heat recovery steam generator and engine, as used with commercially available gasifiers to recover heat of recycled char. An optional feature of IGTC is pressure assist of liquefiers by let-down gasifier pressure to provide a cryo-sink for rejection of gas turbine heat of compression, which may be used to store recovered motor vehicle energy.
Thermochemical recovery increases hydrogen production by 3 times initial syngas hydrogen exclusive of water gas shift hydrogen. The cryo-sink further reduces fuel consumption and carbon emissions. IGCC electricity cost is projected to be 20 % lower than for pulverized coal plants and cost of the IGTC plant still lower. By comparison, cost of advanced nuclear and solar thermal tower electricity is projected at nearly two times higher.
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