Sulphuric acid plant liquid and liquid heat exchanger on-line cleaning method

Abstract

The invention discloses a sulphuric acid plant liquid and liquid heat exchanger on-line cleaning method, which relates to the sulphuric acid production. The invention is characterized in that sulfamic acid, surface active agents and corrosion and scale inhibitors are selected as cleaning scale removing liquid according to ingredients of water side scale of a heat exchanger. A concrete recipe comprises 5 to 10 percent of sulfamic acid, 0.1 to 0.3 percent of surface active agents, 0.1 to 0.4 percent of corrosion inhibitors Lan-826 and the balance water. The method comprises the following steps: filling clean water in a scale removal preparation tank; placing the reagents into water to be prepared into scale removal cleaning liquid with the pH between 1.5 and 2.5; then, circularly injecting the scale removal liquid into the water side of the exchanger by a cleaning pump under the condition without a stop; and controlling the pH value of the cleaning scale removal liquid until a structure is cleanly cleaned. The sulfamic acid in the cleaning scale removal liquid is a high-grade product with the mass percent higher than or equal to 99.8 percent, the surface active agents are sodium n-alkylbenzenesulfonate, and the corrosion inhibitors (Lan-826) have major ingredients of organic nitrogenous compounds. The method of the invention has the advantages of easy acquisition of raw materials, simple and convenient operation and high scale removal efficiency, and is applicable to sulphuric acid production enterprises.

Description

technical field [0001] The present invention relates to sulfuric acid, more specifically to a sulfuric acid production unit, in particular to a liquid-liquid heat exchanger in the sulfuric acid unit. Background technique [0002] The sulfuric acid production process produces a large amount of reaction heat, which needs to be removed by a heat exchanger. After a period of time, the water side of the heat exchanger will foul, which will reduce the heat exchange efficiency, reduce the production capacity of the device, and in severe cases, the device will be forced to stop production. At present, there are two methods for cleaning sulfuric acid heat exchangers: [0003] (1) High-pressure water gun flushing method [0004] For the shell-and-tube heat exchanger, the water side of the shell-and-tube heat exchanger needs to be disassembled, and each heat exchange tube should be washed and descaled with a high-pressure water gun. The disadvantage of this method is that the device...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the device needs to stop production and consumes a lot of energy, the sealing strip is easily damaged during disassembly, the replacement cost is high, and the heat exchange plate is easily damaged by cleaning

[0007] At present, there is only one patent related to the descaling of the heat exchanger of the sulfuric acid plant, namely No. ZL02113704 "A production method for concentrating and removing impurities of dilute sulfuric acid". Conduct countercurrent contact heating, evaporation and concentration in the medium, cool and separate the impurities in the acid precipitated and precipitated in the concentrated sulfuric acid, and solve the problem of scaling and blockage of the heat exchanger caused by the presence of impurities in the dilute acid in the existing evaporation and concentration equipment

So far, there is no patent related to the descaling method of the heat exchanger of the sulfuric acid plant