A kind of graphite heat exchanger cleaning method for silicon steel pickling line

Abstract

Disclosed is a graphite heat exchanger efficient washing method for a silicon steel pickling line. The graphite heat exchanger efficient washing method for the silicon steel pickling line includes following steps: 1) preparing hydrofluoric acid 0.1-0.4wt% in concentration, and placing the hydrofluoric acid in a 1# cleaning fluid tank; preparing ammonia water 0.8-1.2wt% in concentration, and placing the ammonia water in a 2# cleaning fluid tank; preparing a sodium hydroxide solution 10-15wt% in concentration, heating the sodium hydroxide solution so as to raise temperature of the sodium hydroxide solution to 65-80 degree centigrade, adding an amino carboxylic metal chelating agent, and then placing the sodium hydroxide solution in a 3# cleaning fluid tank; 2) disconnecting a graphite heat exchanger acid inlet and outlet pipeline, and using a pipeline to connect a heat exchanger inlet and outlet pipeline with the 1# cleaning fluid tank; 3) starting a cleaning pump, enabling the hydrofluoric acid to enter a heat exchanger and circulate in the heat exchanger for 30-60s; 4) using another pipeline to connect the heat exchanger with the 2# cleaning fluid tank; 5) starting a cleaning pump, and enabling the ammonia water to enter the heat exchanger and circulate in the heat exchanger for 10-15min; 6) using another pipeline to connect the heat exchanger with the 3# cleaning fluid tank; 7) starting the cleaning pump, and enabling sodium hydroxide to enter the heat exchanger and circulate for 3-5h. The graphite heat exchanger efficient washing method for the silicon steel pickling line not only can thoroughly remove stubborn dirt such as silicon sludge and ferric metasilicate, but also does not need to disassemble the heat exchanger, and thereby prevents integrity of the heat exchanger from being destroyed, and furthermore is short in cleaning time, and causes small influences on environment.

Description

technical field [0001] The invention relates to pickling heating technology, in particular to a method for cleaning a graphite heat exchanger used in a silicon steel pickling line. Background technique [0002] Graphite heat exchanger is a common heat exchange equipment in the industrial field. Its principle is to heat or cool the liquid medium through steam, cooling water and other media through the conduction of heat by graphite. For example, in the waste acid recovery process of the silicon steel pickling production line, it is necessary to purify the waste hydrochloric acid (remove silicon, aluminum and other impurities in the acid) through the desiliconization process. In this process, after the waste hydrochloric acid solution is heated to 80°C by a graphite heater, it passes through a dissolving tank filled with steel shavings, so that HCl and iron in the acid solution react to form FeCl 2 , and then overflow from the top of the dissolution tank, and cool down to abo...

AI Technical Summary

Problems solved by technology

In addition, high-concentration hydrofluoric acid is very corrosive, and it also has a certain corrosive effect on the graphite heat exchanger itself (especially the internal binder, etc.), and long-term use will damage the equipment.

It can be seen that using high-concentration hydrofluoric acid as a cleaning agent can achieve the purpose of removing silica mud, but this cleaning method will bring a greater burden to the environment and is not conducive to the maintenance of the equipment itself.

However, if low-concentration hydrofluoric acid is used as cleaning agent, satisfactory cleaning effect cannot be achieved.

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