Intermittent mixer with low pressure drop

摘要

A thermal mixer reduces the temperature of flue gas supplied to a fabric filter. Two spray dry absorbers are operable to cool flue gas. A housing of the mixer has first and second inlet passages for gas from the absorbers, an outlet passage for gas to the fabric filter, and a mixing passage. A set of damper vanes extends in the mixing passage and has a mixing position for mixing the flue gases from the inlet passages to supply mixed gas to the outlet passage at relatively high pressure drop but lower temperature if one of the absorbers in not operating. They have a non-mixing position for passage of gases without mixing and at low pressure drop when both absorbers are operating. The invention can also be used to improve mixing of combined gas streams initially having different chemical compositions or amounts of particle loading.