Low-energy-consumption three-tower nitrogen and oxygen preparation process for flue gas circulation of cement kiln

Abstract

The invention provides a low-energy-consumption three-tower nitrogen and oxygen preparation process for flue gas circulation of a cement kiln. A device required during preparation comprises a filter, a turbine air compressor, an air pre-cooling unit, a molecular sieve adsorber for alternate use, an electric heater, a main heat exchanger, a rectifying tower I, a main condensation evaporator I, a rectifying tower II, a main condensation evaporator II, a rectifying tower III, a main condensation evaporator III, a subcooler, an expansion machine and a liquid nitrogen pump, According to the low-energy-consumption three-tower nitrogen and oxygen preparation process for flue gas circulation of the cement kiln provided by the invention, an air compressor system matched with an original cement kiln is used for providing raw material compressed air, three-tower rectification is adopted, a nitrogen product with pressure and an oxygen product with certain pressure are prepared at the same time, and an oxygen product with certain pressure is used for being mixed with circulating flue gas of the cement kiln rich in carbon dioxide so as to be used as coal feeding air, axial flow air, rotational flow air and the like of the cement kiln, and the nitrogen product with pressure is returned to a user for dust removal of a dust collector.

Description

technical field [0001] The invention relates to the technical field of air separation, in particular to a low-energy-consumption three-tower nitrogen-oxygen production process for cement kiln flue gas circulation. Background technique [0002] At present, the cement industry generally uses the compressed air produced by the air compressor as the dust removal air for the dust collector of the cement kiln. On the one hand, the compression work is wasted, and on the other hand, the compressed air is used to remove dust from the dust collector. Moisture, impurities, etc. will also have adverse effects on the dust collector. [0003] The cement industry is a major emitter of carbon dioxide, and its emissions mainly come from the decomposition of carbonate, combustion of fuel and power consumption. Under China's new vision of carbon peaking and carbon neutrality established in September 2020, in order to accelerate the realization of carbon emission reduction in production proces...

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Problems solved by technology

[0002] At present, the cement industry generally uses the compressed air produced by the air compressor as the dust removal air for the dust collector of the cement kiln. On the one hand, the compression work is wasted, and on the other hand, the compressed air is used to remove dust from the dust collector. Moisture, impurities, etc. will also have adverse effects on the dust collector

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