Zinc oxide desulphurization system

Abstract

The invention discloses a zinc oxide desulphurization system comprising an absorption tower, a settling tank, a slurrying tank, an acidifying tank and a sulfur dioxide desorption tower, wherein the absorption tower is provided with an air inlet, an air outlet, an absorption liquid inlet and an absorption liquid outlet; the settling tank is communicated with the absorption liquid outlet; the slurrying tank is communicated with the settling tank, so that absorbent and supernatant liquor are sent to the absorption tower after being stirred; the acidifying tank is connected with a solid-contained slurry outlet of the settling tank; and the sulfur dioxide desorption tower is connected with the acidifying tank. According to the zinc oxide desulphurization system, by the control on the solid content and the pH value of the absorption liquid in the absorption tower, the problems of equipment blockage and scaling are obviously reduced and the absorption efficiency of SO2 is not influenced. In addition, without the discharge of any waste gas, waste liquid and waste solid, fully-closed operation is achieved. The equipment is simple, the operation and the maintenance are convenient and the cost is low; and compared with the traditional zinc oxide desulphurization, the zinc oxide desulphurization of the invention is short in process, convenient to operate and capable of realizing continuous operation.

Description

technical field [0001] The invention relates to a zinc oxide desulfurization process, in particular to a zinc oxide desulfurization system. Background technique [0002] The traditional zinc oxide desulfurization process is as follows: a slurry containing zinc oxide (ZnO) or pure ZnO mixed with water and sulfur dioxide (SO 2 ) flue gas contacts, reacts, and generates zinc sulfite (ZnSO 3 ), ZnSO 3 After the precipitate is filtered by the filter press, the formed filter residue is sent to the roasting workshop; there are also ZnSO 3 In the case of oxidizing air blowing, the oxidation reaction occurs, and ZnSO is finally generated 4 , containing ZnSO 4 , ZnSO 3 , ZnO and the mixed solution of impurities, after being filtered by a filter press, the filtrate contains a large amount of ZnSO 4 , is sent to the leaching section of the wet system. After the filter residue is dried, it is sent to the slag treatment system or roasting section of the zinc smelter. [0003] The ...

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Problems solved by technology

[0007] (1) ZnSO 3 The viscosity is relatively large, and the ZnSO in the circulating fluid 3 It is easy to deposit in equipment and pipelines, causing scaling and clogging of pipelines, and it is very difficult to clean up after scaling;

[0008] (2)ZnSO 3 Oxidized to ZnSO 4 A large amount of oxidizing air is required for oxidation, and the energy consumption is relatively high. The oxidation effect is controlled by many factors, and the oxidation efficiency is difficult to control;

[0009] (3) Since a large amount of filter residue is filtered out, and the filter residue is difficult to achieve a very low moisture content, if the filter is not well filtered, the filter residue is often like mud, which makes the operating environment of the first floor of the filter press workshop very poor, and these filter residues are transported outside During the process, it is impossible to achieve fully enclosed transportation, causing secondary pollution to the factory area;

[0010] (4) to ZnSO 4 The solution is separated from the slag, or the ZnSO in the slurry 3 To filter out, a filter press is required, and in order to operate continuously, the filter press has to be used one at a time, so that workers have to be arranged to operate and arrange the filter cloth, the filtered residue has to be transported away, and a filter press has to be built. Machine workshop, the entire system occupies a large area, and the operating costs and investment are large;

[0011] Generally speaking, since tail gas desulfurization does not produce any benefits for enterprises, the lower the investment and the simpler the equipment, the better. However, the traditional zinc oxide desulfurization process, from zinc oxide pulping to subsequent filter press filtration, all The scale of the system is not large, but to make the entire process run stably and reliably, the operating environment is good, and the degree of automation is high, the auxiliary facilities such as electricity and instruments must be complete, and the investment often exceeds the company's expectations.

As a result, a lot of equipment can be saved if it can be saved, and if it can be simplified, it will be simplified. As a result, there is no very good demonstration project for the zinc oxide desulfurization process, and it cannot be widely promoted.

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