Desulfurization process of flue gas or waste gas by using external regenerative cycle magnesium sulfate method

Abstract

The invention relates to a desulfurization process of flue gas or waste gas by using an external regenerative cycle magnesium sulfate method. The flue gas or the waste gas containing sulfur dioxide is continuously introduced into an absorbing tower, the sulfur dioxide in the flue gas or the waste gas is absorbed by circularly spraying magnesium sulfite absorbing liquid, the magnesium sulfite in the absorbing liquid is transformed into magnesium bisulfite, the sulfur dioxide in the flue gas or the waste gas is removed, the absorbing liquid at the bottom of the absorbing tower is partially or fully shunted to enter in a regeneration system outside the tower and reacts with magnesium oxide slurry for regeneration, the obtained regenerative liquid is filtered, the magnesium sulfite solid is recovered, the filtrate is returned backed to the absorbing tower for cycle absorption and the sulfur dioxide in the flue gas or the waste gas is continuously removed. Due to the adoption of the regeneration process of the absorbing liquid, the pH value of the regeneration reaction end point and the transformation ratio of the agent are increased, the temperature of the absorbing liquid is reduced, the absorbing liquid has the characteristics of high pH value (7.2-8.5), low temperature (38-48 DEG C) and high absorbing capacity and the absorbent activity of the absorbing liquid is effectively improved.

Description

technical field [0001] The invention relates to a flue gas desulfurization process, in particular to a magnesium sulfite wet flue gas desulfurization process. Background technique [0002] The magnesia wet flue gas desulfurization process was first successfully developed by the American Kaimico Foundation Company in the 1960s. After the 1970s, the Philadelphia Electric Power Company (PECO) cooperated with United & Constructor to study the magnesia regeneration desulfurization process. After thousands of hours of After the trial operation, a full-scale FGD system and two magnesium oxide regeneration systems were put into operation on three generating units (two of which were 150MW and 320MW respectively). The sulfuric acid manufacturing plant sells the reaction product magnesium sulfate directly. Domestic Shandong Binzhou 2×240t / hr boiler flue gas desulfurization adopts magnesium oxide desulfurization process. [0003] The principle of magnesium oxide wet flue gas desulfuri...

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Problems solved by technology

[0007] Limited by the absorption reactivity and absorption capacity of the low-pH absorption liquid, in order to achieve a high desulfurization efficiency, a large liquid-gas ratio is still required, the pressure loss of the flue gas in the absorption system is large, and the power consumption and operating costs are large;

[0008] The regeneration reaction in the tower requires high equipment, high power consumption and low efficiency

[0009] The desulfurization product is oxidized to produce magnesium sulfate with a concentration of only 5-10%, which has low comprehensive utilization value and consumes a lot of suppl

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