Catalytic purification of Claus tail gas or lean H2S waste gas for an overall sulfur…
Multipurpose Gasification Process by Lurgi Oel-Gas-Chemie GmbH
Production of synthesis gas, essentially H2 and CO, from a wide range of gaseous to extra heavy liquid hydrocarbons, as well as emulsions and slurries. Recent new applications are in (chemical) waste gasification. The main advantage over comparable processes is its extreme feedstock flexibility in the quench mode. A boiler mode for highest efficiency is also available.
Continuous noncatalytic partial oxidation process. The quench mode is shown above: hydrocarbon feedstock, moderator (H2O, CO2 or N2) and oxidant (pure or diluted O2, air) are fed through a special burner into the reactor (1), a refractory-lined pressure vessel. Operating conditions are automatically controlled. Hot gas leaves the reactor at the bottom, passing the quench where water is injected to lower the temperature near the saturation value. Quench water washes out most particulates as unconverted carbon (soot) and ash.
Further cleaning occurs in a venturi scrubber (2) from where the gas passes to a medium-pressure steam boiler (3) for heat recovery and to the final cooler (4) before further processing. In hydrogen production, the hot, wet gas from the venturi is passed directly to a raw gas shift conversion. The soot/ash slurry from the process contains virtually all metals and ashes from the feedstock. It is withdrawn via a slurry collector (5) and processed in the metals ash recovery system (MARS) (6). There, soot/ash is filtered from the slurry and incinerated under controlled conditions yielding a saleable metal/ash product. Filtered water is returned for quenching. Excess water is stripped and sent to conventional wastewater treatment. Operating conditions: Actual gasification temperatures of 1,200°C to 1,600°C, pressures from atmospheric to 70 bar (or higher, if economically justified).
Feedstock and oxidant preheat possible in a wide range from 100°C to 600°C, depending on type of feed. Product yields and composition vary with moderator rate and type of feed. Water quench is selected for highest feedstock flexibility. At low-salt contents, the boiler mode can recover heat as high-pressure steam, raising overall efficiency.
Economics: Characteristic consumption and production rates per ton of heavy residue feedstock: 1 to 1.1 t O2 (100%), export 0.5 t MP steam to 2.2 t HP steam, 2.2 t raw syngas (dry) equiv. to 2,600 Nm3 H2 + CO. Cold gas efficiency is 82% to 85%. In boiler mode, thermal efficiencies including HP steam generated are about 95% based on feedstock HHV. This makes the process attractive for syngas production and for an IGCC power plant. A highly integrated and efficient power complex will be in the range of $800/kW total invested cost.
Licensor: Lurgi Oel-Gas-Chemie GmbH
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