Initial startup of the Texaco gasifier
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During normal operation, the gasifier and scrubber are supplied with a stream of condensate from the shift reactor. But during the initial startup of the gasifier, where does this stream of shift condensate come from? Should desalinated water be used as a temporary substitute?
The original model didn’t have condensate; only desalinated water could be used
Establish a water balance using water for boiler operation or demineralized water
Only deoxygenated water can be used; in principle, demineralized water is not allowed, as it has not been deoxygenated. Moreover, the pressure in the condensate tank is high, so you can’t add desalinated water either; it’s better to use medium-pressure deoxygenated water.
This water will be available once the transformation is completed; deoxygenated water (DW) is used, and some plants employ high-pressure ash water pumps. Some use a condensate pump
During the initial operation, no change was made to the condensate. The condensate is generated by the saturation steam produced when the syngas leaving the gasification unit enters the rear system; since that system was not yet in operation, pure deionized water had to be used. The deionized water supplied by the relevant staff entered the deaerator, where it was heated to over 104 degrees under the action of steam in order to remove oxygen and prevent equipment corrosion. After that, the water was sent to the condensate pump, which pressurized it and sent it to both above and below the trays in the scrubber tower. In some installations, this water was also added to the syngas pipeline at the exit of the gasification furnace to wash away dust contained in the syngas.
Without changing the condensate, we use deoxygenated water in place of the condensate for washing the syngas, or we use boiler feedwater; in that case, it is the boiler feedwater that is used.
During the initial startup of the gasifier, this water is temporarily replaced with deoxygenated water.