Method for preparing CO2-N2 mixed gas from boiler flue gas to be used for clarification process of sugar production

Abstract

The invention discloses a method for preparing CO2-N2 mixed gas from boiler flue gas to be used for a clarification process of sugar production. The method of the process comprises the following steps of: collecting the boiler flue gas by an air blower, making the boiler flue gas pass through a dust catcher, a heat exchanger and a gas-water separator; desulfurizing by alkaline water or in a pressure-swing adsorption tower to obtain pretreated gas; and adsorbing and desorbing the pretreated gas in the adsorption tower of a pressure-swing adsorption system to obtain the mixed gas containing 18%-40% of CO2 and 54%-74% of N2 in percentage by volume. The mixture is delivered into a mixed juice carbonating tower and an upward-floating clarifier or a syrup carbonating tank and the upward-floating clarifier, and the mixed juice or syrup is clarified by a clarifying method of half carbon and half sulfur. The invention is used for the clarification process of sugar production by a sulfurous method, and the clarification effect of the mixed juice or the syrup is good. By adopting the invention, CO2 discharged from the boiler flue gas is reduced, and the ecological environments are protected; meanwhile, filter mud generated in the production process can be used as a fertilizer for crops, thus the invention has an important meaning for making full use of resources and protecting environments.

Description

technical field [0001] The present invention relates to a kind of sulfurous acid process sugar production method, specifically is to purify and produce CO2 from the boiler flue gas of sugar factory. 2 -N 2 Mixed gas, and used in the method of sulphite sugar clarification process. Background technique [0002] The clarification efficiency of the sulfite sugar production process is lower than that of the carbonation sugar production process because it is difficult to remove non-sugar impurities such as colloids, polyphenols, and iron ions in the sugar juice. Therefore, the quality of sugar products produced by the sulfite sugar process is worse than that produced by the carbonation sugar process. [0003] At present, lime, phosphoric acid and sulfur dioxide are used as the main clarifiers in the sulfite sugar production process, and the clarification process of mixed juice and syrup is completed through steps such as ash addition, sulfur fumigation, neutralization, and preci...

AI Technical Summary

Problems solved by technology

The patent does not mention how to use flue gas and fermentation gas to produce CO 2 Mixed gas with a content of 60-90%, in fact, the sugar factory produces CO from flue gas and fermentation gas 2 The cost of mixed gas with a content of 60-90% is quite high and difficult, and it is very difficult to treat the syrup with such a mixed gas after being filtered by a plate and frame filter to obtain a large amount of alkaline filter mud that cannot be reused, causing great environmental pollution