Treatment method of calcination tail gas in the production process of titanium dioxide

Abstract

The invention discloses a method for treating calcined tail gas in the production process of titanium dioxide, which comprises the steps of: 1) dust removal; 2) preliminary heat exchange, discharging the calcined tail gas after dust removal into a waste heat boiler system for heat exchange with process water, The calcined tail gas is initially cooled; 3) heat exchange is performed again, and the calcined tail gas after the initial cooling enters the Venturi system to be further cooled by spraying waste sulfuric acid; 4) desulfurization. The method for treating the calcination tail gas in the titanium dioxide production process of the present invention adopts a waste heat boiler system with a high waste heat recovery utilization rate, and through step-by-step heat exchange, the heat in the calcination tail gas can be efficiently recovered and used in other processes of the titanium dioxide production line, greatly Energy and water consumption are saved, and the desulfurization rate of the calcination tail gas is significantly improved through desulfurization.

Description

technical field [0001] The invention belongs to the field of titanium dioxide production, and in particular relates to a method for treating calcination tail gas in the production process of titanium dioxide. Background technique [0002] Titanium dioxide (TiO 2 ) is the most important white pigment widely used at present, and is widely used in coatings, papermaking, ink and other fields, and its demand is in direct proportion to GDP. At present, the annual production capacity of titanium dioxide in the world is more than 5 million tons, and the annual production capacity of titanium dioxide in China is more than 2 million tons. The price is about 15,000-22,000 yuan / ton. In terms of production methods, except for the Jinzhou Titanium Dioxide Factory which uses the chlorination method, the rest are all produced by the sulfuric acid method. A prominent problem in the current sulfuric acid titanium dioxide production process is environmental protection and energy saving. [...

AI Technical Summary

Problems solved by technology

The problem with this method is that the waste heat utilization efficiency is low, and it is necessary to build a waste acid concentration device, and the pre-concentrated sulfuric acid needs to be kept warm.

The problem with this method is that the factory must be equipped with a set of graphite towers for concentrating sulfuric acid, and it is prone to equipment failure

The problem with this method is that the utilization of thermal efficiency is low, non-electric air conditioning equipment needs to be configured separately, and it is repeated with existing refrigeration equipment, which increases investment

The problem with this method is that there is no heat recovery

The problem with this method is that the heat loss of the hot waste gas is large during the waste acid spraying process, the waste heat utilization efficiency is low, and the harmful and useless gases in the calcination tail gas return to the kiln, which will adversely affect the calcination process.

[0014] To sum up, in the prior art, the waste heat of the calcination tail gas of the titanium dioxide rotary kiln is not utilized or the waste heat utilization efficiency is low, and the sulfide discharged from the calcination tail gas is difficult to control, and the calcination tail gas often fails to meet the standard.