A Cascaded Utilization System of Exhaust Heat from Rotary Kiln Tail Gas Calcined with Titanium Dioxide

Abstract

The invention relates to the technical field of utilization of tail gas waste heat, in particular to a gradient utilization system of the tail gas waste heat of a titanium dioxide calcining rotary kiln. The system comprises a primary waste heat utilization system, a secondary waste heat utilization system, a steam pocket transfer system, a tail gas flow pipeline system and a water way pipeline system. The steam pocket transfer system comprises a steam pocket, the lower portion of the steam pocket is connected with a steam pocket water outflow pipeline, and the top of the steam pocket is connected with a steam pocket water inflow pipeline and a steam outflow pipe. An adopted heat exchanger is high in efficiency and uniform in temperature, damage of temperature stress generated by non-uniform temperatures of all sections to equipment is avoided, and meanwhile as the heat exchanger is composed of inner-layer pipes and outer-layer pipes, the heat exchanger is more suitable for corrosive environments.

Description

technical field [0001] The invention relates to the technical field of tail gas waste heat utilization, in particular to a cascaded utilization system for tail gas waste heat of a titanium dioxide calcined rotary kiln. Background technique [0002] The sulfuric acid method produces titanium dioxide. The tail gas produced by the calcination of the rotary kiln usually contains sulfur oxides, water vapor, dust and other mixtures. Because the tail gas contains sulfur oxides, the dew point temperature rises, generally around 200 ° C, and the dew point temperature rises The sulfur oxides in the exhaust gas are easily combined with water vapor to form acid mist, which leads to the intensified corrosion of metal equipment. [0003] The existing tail gas treatment system, considering the corrosion of metal equipment, directly feeds the tail gas into the waste acid, uses the waste acid to absorb the sulfur oxides in the tail gas, and uses the heat of the tail gas to concentrate the wa...

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Problems solved by technology

[0005] The heat transfer oil working medium heat exchange technology is to use the waste heat of the exhaust gas to heat the heat transfer oil, control the temperature of the exhaust gas to drop to 210 ℃, enter the follow-up process, and use the heat of the heated heat transfer oil to generate water vapor; due to the heat transfer oil working medium heat exchange technology The heat capacity is limited, and the gravity single-layer heat pipe phase-change heat technology has been tried, and the heat exchange efficiency has been greatly improved. However, the migration direction of the phase-change working medium in the gravity heat pipe phase-change heat is along the axis of the pipe, so the temperature uniformity of each section is poor. The temperature stress affects the service life of the pipeline. At the same time, once the temperature of the exhaust gas fluctuates below its dew point temperature during the production process, the single-layer tube gravity heat pipe phase transfer heat is easily affected by the acid corrosion of the exhaust gas and affects the service life, which requires high stability of the exhaust gas temperature.

[0006] In addition, the limited heat exchange technology in the heat transfer oil working medium heat exchange technology leads to bulky equipment, and the gravity single-layer heat pipe phase change heat technology has its own defects, and the temperature uniformity of each section is poor, making it difficult to achieve the ideal effect of exhaust gas waste heat recovery

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