Titanium dioxide calcination exhaust gas comprehensive utilization system and exhaust gas processing method

Abstract

The invention discloses a titanium dioxide calcination exhaust gas comprehensive utilization system and an exhaust gas processing method, and relates to the field of titanium dioxide calcination exhaust gas recycling. The system comprises an exhaust gas purification device, a heat energy recovering device, a steam using device and a waste liquid recovering device, the exhaust gas purification device is in circulated connection with the heat energy recovering device, the heat energy recovering device is connected with the steam using device, and the waste liquid recovering device is connected with the exhaust gas purification device; the exhaust gas purification device comprises a dust removal device, a desulfurizer, a denitrification device, a demisting device, an induced draft fan and a chimney, and the heat energy recovering device comprises a primary heat energy recovering device, a secondary heat energy recovering device and a thrice heat energy recovering device which are sequentially connected; and the steam using device comprises a power generation system and a heat supply system. According to the titanium dioxide calcination exhaust gas comprehensive utilization system andthe exhaust gas processing method, while the environmental requirement is met, the calcination exhaust gas heat energy using rate is effectively improved, and the titanium dioxide calcination exhaustgas economical value is improved.

Description

technical field [0001] The invention relates to the field of recovery and utilization of tail gas from calcination of titanium dioxide, in particular to a comprehensive utilization system of tail gas from calcination of titanium dioxide and a treatment method for tail gas. Background technique [0002] Titanium dioxide (titanium dioxide) is non-toxic, good physical and chemical stability (not soluble in any acid and alkali after calcination at 1000°C), high refractive index (2.55-2.70), and strong whiteness and tinting strength (Reynolds value 1150~1950), hiding power (40~50g / m 2 ), temperature resistance, anti-chalking and other characteristics, it is called "the king of pigments". It is not only a white pigment with excellent performance, but also an important chemical raw material, widely used in coatings, inks, plastics, rubber, paper and chemical fiber industries. [0003] The production process of titanium dioxide can be divided into sulfuric acid method, chloride me...

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Problems solved by technology

[0006] But at the same time, this method also has the following disadvantages: the titanium dioxide content is not high, and the ilmenite with more impurity content, titanium slag and sulfuric acid are used as raw materials, resulting in many processes, long process flow, intermittent operation, and large consumption of sulfuric acid, steam and water. , there are many waste by-products (3 to 4 tons of ferrous sulfate and 8 to 10 tons of dilute sulfuric acid are produced for every 1 ton of titanium dioxide), which seriously pollutes the environment, and the treatment and utilization are more complicated and costly, especially the production A large amount of high-heat exhaust gas is generated during the process. The exhaust gas temperature is 300-400°C. The exhaust gas is mainly composed of water vapor, oxygen, nitrogen, carbon dioxide, sulfur trioxide and a small amount of sulfur dioxide, metatitanic acid, and titanium dioxide solid washing powder. The average emission of titanium dioxide is 17000Nm 3 Exhaust gas; allowing it to dissipate has huge environmental protection and energy waste problems

[0007] Some titanium dioxide manufacturers have installed tail gas waste heat utilization devices to process and utilize the exhaust gas of the calciner, but the tail gas waste heat utilization devices currently on the market are relatively simple to treat the tail gas, such as using the tail gas to heat concentrated acid, or heating the secondary washing water for recycling In the first washing process section, or using heat energy to generate low-pressure saturated steam, etc., a large amount of high-level heat is used as low-level heat energy in the related treatment process, and the efficiency of heat energy utilization is low. At the same time, the exhaust gas is not effectively desulfurized and denitrified, causing environmental pollution.

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