A start-up method of plate-fin heat exchanger of air separation plant

Abstract

The invention relates to a start-up method for a plate-fin heat exchanger of an air separation plant. After the supercharger and the gas expander are started, the pressure of the lower tower of the air separation tower is controlled not to be higher than the alarm value, and the temperature of the hot end of the low-pressure air is prevented from being lower than the interlock value, causing the air separation to stop. The low-pressure air pipe at the inlet of the lower tower of the air separation tower enters the lower tower of the air separation tower after passing through the low-pressure plate-fin heat exchanger, and is connected with the dirty nitrogen pipe at the inlet of the cold end of the subcooler, and on the outlet air pipe of the low-pressure plate-fin heat exchanger Set the pressure regulating valve 1 to control the pressure of the lower tower through the pressure regulating valve 1, fully open the pressure regulating valve 1, and the low-pressure air enters the dirty nitrogen pipeline to reduce the pressure of the lower tower. The advantage of the present invention is: solved 60000m 3 / h The problem of low air temperature at the hot end of the low-pressure plate-fin heat exchanger at the beginning of the cold start of the oxygen generator ensures that the oxygen generator can be started successfully at one time.

Description

technical field [0001] The invention belongs to the field of air separation equipment, in particular to a method for starting a plate-fin heat exchanger of an air separation equipment. Background technique [0002] A 60,000m2 newly put into production in an oxygen plant 3 / h Large-scale air separation equipment, designed and manufactured by Air Liquide, adopts nitrogen water tower, refrigerator pre-cooling, molecular sieve adsorption, supercharged turbo expander refrigeration, and high and low pressure two plate-fin main heat exchangers. The internal compression process of full rectification to produce argon. At the beginning of the cold start of the air separation plant, the temperature of the hot end of the plate-fin heat exchanger is often lower than the interlock value, and the air separation shuts down, which leads to the failure of the air separation start-up, and there is a risk of low-temperature brittle fracture of the air pipe. Contents of the invention [0003...

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Problems solved by technology

[0003] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a start-up method for the plate-fin heat exchanger of the air separation plant to solve the problem of 60000m 3 / h The problem of low air temperature at the hot end of the low-pressure plate-fin heat exchanger at the beginning of the cold start of the oxygen generator ensures that the oxygen generator can be started successfully at one time and avoid secondary accidents.

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