Waste heat recovery device applied to air separation purification system and key parameter determination method thereof

Abstract

The invention discloses a waste heat recovery device applied to an air separation purification system and a key parameter determination method of the waste heat recovery device. The key parameter determination method comprises the steps that actual temperature and flow data of cold blowing polluted nitrogen of an air separation purification device are collected; for the temperature, nonlinear fitting is adopted to obtain the temperature and flow change rule of the discharged cold blowing polluted nitrogen; in order to improve the waste heat recovery capacity, a phase change heat accumulator adopts a multi-stage form, a multi-stage phase change heat accumulator mathematical model is established based on a system of ordinary differential equations, and a numerical method is adopted to sequentially solve the corresponding system of ordinary differential equations; the maximum heat release of the phase change heat accumulator to the recycled polluted nitrogen is taken as an objective function, and meanwhile, corresponding constraint conditions are set, so that the calculation efficiency is improved; and the multi-stage phase change heat accumulator model is optimized by using a differential evolution algorithm to obtain key parameters such as optimal phase change temperature and quality of a phase change material in the phase change heat accumulator. The waste heat recovery effectof the cold blowing polluted nitrogen is improved to the greatest extent, the power of an electric heater is reduced, and energy conservation and consumption reduction of the air separation purification system are realized.

Description

technical field [0001] The invention relates to the technical field of air separation and purification devices, in particular to a waste heat recovery device applied to an air separation and purification system and a method for determining key parameters thereof. Background technique [0002] Air separation units usually use cryogenic rectification to obtain liquefied air. In order to prevent impurities such as water vapor and carbon dioxide from affecting the subsequent rectification process, a purification system is required to pretreat the air. At present, the purification system is mainly a molecular sieve adsorber, which works according to the process of adsorption-desorption-adsorption. According to statistics, the energy consumption of molecular sieve adsorbers accounts for about 16% of the total energy consumption of air separation plants. If the operating costs can be reduced, enterprises can gain a greater advantage in market competition. In order to realize the r...

AI Technical Summary

Problems solved by technology

The conventional air separation and purification system only includes two molecular sieve adsorbers working in parallel. Due to the time difference, the heat contained in the cold blown nitrogen gas is difficult to use, and it is usually emptied directly, resulting in a large waste of energy.

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