A kind of process method for recovering waste heat energy of alumina pressure cooking and dissolution process backwater

Abstract

The invention discloses a process method for recovering heat energy of backflow waste heat from aluminum oxide autoclave digestion process.Two-stage heat exchangers are arranged in a hot water station. A first-stage heat exchanger is a water-water heat exchanger. A second-stage heat exchanger is a gas-water heat exchanger. The first-stage heat exchanger, as the water-water heat exchanger, is used for recovering backflow waste heat of the process and heating cold water. The second-stage heat exchanger, as the gas-water heat exchanger, serves as an auxiliary spare heat exchanger. The process method for recovering heat energy of backflow waste heat from aluminum oxide autoclave digestion process has following beneficial effects: (1) a reasonable method is utilized for process backflow temperature of the autoclave digestion process in order to be favorable to cyclic utilization and heat energy of waste heat produced by backflow and temperature reduction is recovered; (2) steam consumption of the hot water station used for heating hot water is reduced and operation cost is saved; (3) a system is easy and is convenient to apply, operate and maintain.

Description

technical field [0001] The invention relates to a process method for recovering waste heat heat energy of backwater in an alumina pressure cooking and dissolution process. Background technique [0002] In the alumina production process, the pressure cooking dissolution process usually uses saturated steam with certain parameters as the heating heat source of the system. In the steam heat exchange section of the process, the latent heat of steam is mainly used to heat the material, that is, the steam condensed water after heat exchange is saturated water at that pressure. Taking a certain project as an example, the saturated steam pressure is 6.4MPa, and the corresponding condensate return temperature is 280°C. [0003] At present, the mainstream way to recover process return water is the three-level detection of return water, that is, when the process return water meets the boiler feed water quality requirements after testing, it is directly supplied to the boiler feed wate...

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Problems solved by technology

[0004] However, at this stage, the maximum water temperature of the deaerator in the self-provided power plant boiler feed water system set up for alumina production should not exceed 158°C, the water temperature of the mixed bed in the chemical water treatment room should not exceed 60°C, and the industrial water drainage pipe network in the plant should not exceed 158°C. The drainage temperature requirement should generally not exceed 80°C

Therefore, no matter which stage the return water of the pressure cooking dissolution process is in, it needs to go through the cooling process, and this part of the heat is usually wasted or not used reasonably

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