Method and device for concentrating waste acid in titanium dioxide production by sulfuric acid process

Abstract

The invention discloses a method for concentrating waste acid in a titanium dioxide production by a sulfuric acid process. The method comprises the following steps: (1) transporting 30% of waste acid to a single-effect evaporator by a first middle acid storage tank; (2) heating up the single-effect evaporator by low-pressure vapour to reach a temperature needed for evaporating waste acid, and connecting with an exterior vacuum pump after being cooled by a condenser; (3) connecting an ejector on the single-effect evaporator, wherein the injector is contacted with outside middle-pressure vapour to form negative pressure; (4) heating up a second-effect heater by exterior middle-pressure vapour to raise the temperature to the evaporation temperature for the waste acid in the second-effect evaporator, wherein the secondary vapour generated in the second-effect evaporator is connected with an outside vacuum pump after being cooled by the condenser. According to the method, the outside middle-pressure vapour enters the injector to form negative pressure, so that secondary vapour generated in the single-effect evaporator is continuously introduced to the second-effect heater, thereby improving the evaporation efficiency, relieving the device corrosion and greatly improving the operation efficiency of the system. The invention also discloses a device for concentrating the waste acid generated in the titanium dioxide production by the sulfuric acid process.

Description

technical field [0001] The invention relates to a method for concentrating waste acid in the production of sulfuric acid titanium dioxide, and also relates to a set of industrialized production devices designed using the method. Background technique [0002] In the production process of sulfuric acid titanium dioxide, a large amount of waste acid with a concentration of about 20% (in the form of H 2 SO 4 Each ton of titanium dioxide produces about 6 to 8 tons of waste acid. If this part of waste acid is not recycled, it will cause a lot of waste of precious resources. If it is not handled properly, it will cause serious harm to the environment (such as direct emissions, etc.). [0003] Concentration and reuse of waste acid is currently one of the most effective ways to solve the comprehensive utilization of waste acid and energy conservation and environmental protection. [0004] The existing waste acid concentration is concentrated in two stages, namely the flue gas conc...

AI Technical Summary

Problems solved by technology

[0009] However, the existing treatment method often results in a positive pressure state in the first-effect evaporator V5404, the temperature of the first-effect gas phase thermometer TIA1 is too high, reaching above 100°C, and the first-effect liquid phase of the waste acid in the first-effect evaporator V5404 The temperature of the thermometer TIA2 reaches about 110°C, and the water evaporates slowly

Due to the high temperature of the existing method, the evaporation efficiency of the system is low, the requirements for corrosion-resistant materials and equipment are strict, the equipment is damaged quickly, and the continuous operation period of the system is short.

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