Washing liquid applied to station boiler and washing method

Abstract

The invention discloses a washing liquid applied to a station boiler and a washing method; wherein the washing liquid comprises the following components according to mass percent: 4-12% of ethylene diamine tetraacetic acid(EDTA) and ethylene diamine tetraacetic acid disodium salt, moderate amount of sodium hydroxide, 0.2-0.3% of methenamine, 0.1-0.2% of thiourea or di-o-tolyl-thiourea, 0.05-0.08% of mercaptobenzothiazole, 0.01-.0.3% of alkylphenol polyethenoxy ether(OP-10), 0.03-0.06% of octyl phenol polyethenoxy ether (TX-10), and the excess of water. In the method of the invention, processes such as acid cleaning, passivation and inhibition are organically combined, thus simplifying the cleaning sequences; as alkaline matter is generated by the washing liquid in the process of decomposition and incrustation dissolving, pH value of the washing liquid can be increased along with the washing process and the pH value is more than 8.5, thus realizing one-step completion of washing and passivation.

Description

technical field

[0001] The invention belongs to a chemical preparation and a method for cleaning boilers, in particular to a cleaning liquid and a cleaning method for power plant boilers. Background technique

[0002] Large-scale thermal power plant boilers must be chemically cleaned no matter during the infrastructure construction period or when the unit is running for a period of time when the scale of the furnace tube reaches the corresponding standard requirements, so as to obtain a clean heating surface, thereby achieving energy saving and consumption reduction and preventing the corrosion of the furnace tube. Purpose. Commonly used cleaning methods include the use of hydrochloric acid, citric acid, EDTA ammonia salt, hydrofluoric acid, sulfamic acid and sulfuric acid, etc., which require two major steps of cleaning, descaling and passivation including pickling, water rinsing and rinsing. The cleaning time is long, the cleaning process is complex and consumes a large a...