Method and apparatus for treating acidic tail gas by using ammonia process flue gas

Abstract

A flue gas-treating method for treating acid tail gas by using an ammonia process, comprising the following steps of: 1) controlling the concentration of sulfur dioxide in an acid tail gas entering an absorber to be ≦30,000 mg / Nm3; 2) spraying and cooling with a process water or / and an ammonium sulfate solution in the inlet duct of the absorber or inside the absorber; 3) providing an oxidation section in the absorber, wherein the oxidation section is provided with oxidation distributors for oxidizing the desulfurization absorption solution; 4) providing an absorption section in the absorber wherein the absorption section achieves desulfurization spray absorption by using absorption solution distributors via an absorption solution containing ammonia; the absorption solution containing ammonia is supplied by an ammonia storage tank; 5) providing a water washing layer above the absorption section in the absorber, wherein the water washing layer washes the absorption solution in the tail gas to reduce the slip of the absorption solution; 6) providing a demister above the water washing layer inside the absorber to control the concentration of mist droplets contained in the cleaned tail gas. In the coal chemical industry, the integration of the Claus sulfur recovery process and the ammonia desulfurization technology can reduce the investment of the post-treatment and simplify the operation process, and provide intensive advantages to the environmental control of plants.

Description

FIELD OF THE INVENTION[0001]This invention relates to a purification technology and an apparatus for industrial flue gas such as an acid tail gas (flue gas) or the like in chemical (coal chemical) process. Specifically, the invention relates to a desulfurization technology and an apparatus using ammonia as the absorbent to remove sulfur dioxide from a flue gas and yield a fertilizer as a byproduct. This invention belongs to the technical fields of environmental protection, power and chemical industry or the like.BACKGROUND OF THE INVENTION[0002]Sulfur dioxide discharged from industrial processes is the major source of acid rain and sulfur dioxide pollution. In order to control sulfur dioxide emission to improve environmental quality, industrial flue gas desulfurization is necessary and must be enforced.[0003]Acid tail gas generally refers to the tail gas generated from the following steps: a sulfur-containing gas generated from the chemical (especially coal chemical) process firstly...

AI Technical Summary

Benefits of technology

The invention provides a method for efficiently treating acid tail gas using an ammonia process. The combination of the Claus process and ammonia desulfurization technology can effectively improve desulfurization efficiency and control ammonia slip and aerosol generation. The process is simple and operating cost is low. The desulfurization efficiency is over 95% and ammonia recovery ratio is over 96.5%. The invention includes an absorption section to achieve over 90% desulfurization efficiency and a water washing layer to reduce slip of the absorption solution. The invention also includes a spray cooling system to save energy and a byproduct recovery system to reduce secondary pollution. The invention improves air pollution control and makes the process more economically viable. The design of the devices is simple and reliable. The combination of a cooling spray layer and an absorption spray layer makes it more convenient to treat acid tail gas.

Problems solved by technology

Sulfur dioxide discharged from industrial processes is the major source of acid rain and sulfur dioxide pollution.

All these processes have the disadvantages of complicated process, high investment, high operating cost, difficult operation or the like.

Such control is complicated, and if stable control cannot be achieved, the sulfur recovery efficiency will be greatly affected.

This method also has the disadvantages of high capital and operating costs, and complicated operation or the like.

Capital and operating costs for limestone desulfurization device are high, and especially, it requires high-quality limestone, and the market for the desulfurization byproduct (gypsum) is limited.

Sodium carbonate and sodium hydroxide desulfurization, which is often used in acid tail gas desulfurization treatment, consumes sodium carbonate and sodium hydroxide, and the market for its byproduct sodium sulfate is limited, resulting in high operating cost and poor reliability.

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