A system and method for pickling and drying biomass from boiler flue gas

Abstract

The invention relates to a system and method for boiler flue gas pickling and biomass drying. The method adopts alkali eluting by carbonic acid, the CO2 of a boiler flue gas is dissolved in water to produce weak acid carbonic acid, which is non-toxic, harmless and low in cost and can improve the removal rate of alkali metal in a biomass, that is, the flue gas as a first-stage dryingheat source iscooled and dried in the first stage and then enters a pickling chamber to form a weak acid environment to remove the alkali metal in the biomass, and the pressure in the pickling chamber is controlledby controlling the exhaust rate of the pickling chamber, thereby changing the solubility of the CO2 and achieving efficient alkali removal. The solid-liquid separation and reverse osmosis device canobtain not only the biomass after pickling, but also the circulating water and a high ion concentration solution. The heated tail flue gas and part of the high temperature flue gas before a economizerare used as a heat source to dry the pickled biomass fuel in the second stage to meet the moisture requirement of the biomass fuel, the high temperature flue gas is cooled and dried in the second stage and returned to a front flue box of the boiler, and the NOx generation is reduced by controlling the boiler temperature.

Description

technical field [0001] The invention relates to a system and method for pickling boiler flue gas and drying biomass. Background technique [0002] In recent years, CO 2 The greenhouse effect caused by emissions has attracted widespread global attention, and biomass can convert CO through photosynthesis 2 Fixation, in the carbon cycle of bioutilization and regeneration, the carbon dioxide released by burning biomass is equivalent to the carbon dioxide absorbed and fixed, so renewable biomass can almost achieve "CO2 2 "Zero emission" can well replace fossil energy. At the same time, people also attach great importance to the utilization and development of biomass energy. Biomass combustion technology develops rapidly and industrial applications are gradually mature. However, due to the high alkali metal content of biomass, Especially K element, under high-temperature combustion conditions, the alkali metal will evaporate into the gas and condense on the heat exchange surface...

AI Technical Summary

Problems solved by technology

However, due to the high alkali metal content of biomass, especially the K element, under high-temperature combustion conditions, the alkali metal will evaporate into the gas and condense on the heat exchange surface, or react with other inorganic elements to form a strong bond. At the same time, these alkali metals will promote the formation of low-temperature eutectic, lower the melting point of ash, and lead to a large amount of slag, which will not only reduce the thermal efficiency of the boiler, but also seriously corrode The heat exchange surface of the boiler, causing pipe bursts and other phenomena

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