Tail gas treating method and treating system for preparing zirconium oxychloride by boiling chlorination process

Abstract

The invention relates to the field of tail gas treatment by preparing zirconium oxychloride by a boiling chlorination process, in particular to a tail gas treating method and treating system for preparing the zirconium oxychloride by the boiling chlorination process. The tail gas treating method by preparing the zirconium oxychloride by the boiling chlorination process comprises the following steps: respectively introducing a liquid-state absorbing medium into a falling film absorber and a packing absorbing column; firstly introducing the tail gas containing hydrogen chloride into the falling film absorber, introducing the residual tail into the packing absorbing column along a tail gas conveying pipe, then performing hydrogen chloride gas concentration detection and exhausting tail gas. The tail gas treating method disclosed by the invention has the beneficial effects that dilute hydrochloric acid or water is utilized for absorbing hydrogen chloride gas, finally chlorine is converted into hydrochloric acid, alkali liquor is prevented from being utilized in a tail gas treating process, a sodium hypochlorite solution is prevented from being generated, tail gas treating cost and difficulty are reduced, effects of other components in the tail gas are avoided, the problem of excessively treating in the prior art is avoided, and the problems in the prior art are economically and effectively solved.

Description

technical field [0001] The invention relates to the field of tail gas treatment of zirconium oxychloride prepared by boiling chlorination, in particular to a tail gas treatment method and system for preparing zirconium oxychloride by boiling chlorination. Background technique [0002] Zirconium oxychloride by boiling chlorination requires chlorine gas, zircon sand (zirconium silicate), petroleum coke, metal silicon (or silicon carbide or a mixture of the two) as raw materials, and occurs in a chlorination furnace at 900°C-1200°C The reaction produces zirconium tetrachloride and silicon tetrachloride, the silicon tetrachloride is purified as a by-product, and zirconium tetrachloride reacts with water to generate zirconium oxychloride and hydrochloric acid. [0003] The tail gas contains a small amount of chlorine and a large amount of carbon monoxide. When the temperature drops, a chemical reaction easily occurs to generate phosgene. Phosgene is a highly toxic substance, whic...

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Problems solved by technology

[0003] The tail gas contains a small amount of chlorine and a large amount of carbon monoxide. When the temperature drops, a chemical reaction easily occurs to generate phosgene. Phosgene is a highly toxic substance, which brings troubles to subsequent treatment.

Even if the conditions are controlled so that the two do not react, lye must be used to absorb chlorine gas in order to use carbon monoxide as a raw material for the production of fuel or other products, which also causes high disposal costs

In addition, the lye cannot selectively absorb chlorine gas during the operation of the equipment, and its absorption reaction to carbon dioxide also proceeds at the same time, and the carbon dioxide content in the tail gas is generally more than 5 times that of chlorine gas. Therefore, in order to absorb chlorine gas, it is necessary to use More than 6 times of the required lye can make the chlorine gas be completely absorbed. On the one hand, this increases the consumption of lye, and on the other hand, the resulting sodium hypochlorite solution has a low effective chlorine content, which cannot meet the requirements of relevant national standards.

However, the content of carbon dioxide does not have too much influence on the treated tail gas. It only reduces the concentration of carbon monoxide. It is not necessary to remove it as a fuel. Removing carbon dioxide is an excessive treatment of tail gas, which not only increases the cost, but also no apparent beneficial effect

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