Dry sorbent injection during non-steady state conditions in dry scrubber

摘要

Methods of reducing emissions levels during upset periods such as startup are disclosed for use with a dry scrubber desulfurization system. A dry calcium hydroxide powder is injected into the gas flowpath and hydrated in the spray dryer absorber. The resulting hydrated powder is then deposited on the filter bags in the baghouse. This can be done at lower temperatures than the spray dryer absorber would otherwise be operable, enabling desulfurization to occur earlier in the combustion process, such as during startup of a cold combustion system at ambient temperature. The operation of the combustion system can also be backed up, made up, trimmed, or augmented depending on various operating scenarios.

主权项

1. A method for reducing combustion emissions produced during non-steady state operating conditions in a combustion system having a gas flowpath that travels from a combustion chamber through a spray dryer absorber to a baghouse downstream of the spray dryer absorber, the method comprising:
mixing a dry calcium hydroxide powder into a carrier gas in the gas flowpath at an injection location downstream of the combustion chamber and upstream of the baghouse; spraying water into the carrier gas in the spray dryer absorber to humidify and reduce the temperature of the carrier gas; and depositing the calcium hydroxide powder in the baghouse to form a filter cake that reduces combustion emissions.