Glauberite pipeline scale descaling agent and application thereof

Abstract

The invention discloses a glauberite pipeline scale descaling agent and application thereof. The descaling agent comprises the following components in percentage by weight: 10-25% of NaOH, 5-15% of Na2S2O35H2O, and 0.05-0.5% of sodium polyacrylate. The descaling agent provided by the invention can be used for transforming insoluble CaSO4 into soluble Ca(OH)2 and Na2SO4; a proper amount of Na2S2O35H2O serving as a complexing agent is added and complexed with Ca<2+> in Ca(OH)2 to form a more stable complex, a new precipitate is prevented from generating, and a dissolution reaction is promoted to happen; a proper amount of EDTA (ethylene diamine tetraacetic acid) and a proper amount of polyacrylamide are added to realize a more remarkable scale inhibition effect; and acid is not contained in the components of the descaling agent, and no acid is generated in the descaling process, so that the descaling agent has small corrosive influence on a salt manufacturing pipeline and small influence on the mechanical performance of the salt manufacturing pipeline; and after being subjected to simple sediment treatment, a residual solution obtained after filtering can be returned to a bittern pre-treatment system, so that the alkaline solution in the residual solution can be utilized, so that sewage is hardly drained, and the descaling agent is environmentally-friendly.

Description

technical field [0001] The invention relates to a chemical descaling agent, in particular to a chemical descaling agent for removing glauberite. Background technique [0002] Glauber's salt is a double salt of sodium sulfate and calcium sulfate, the chemical formula is xNa 2 SO 4 ·yCaSO 4 ·nH 2 O. The solubility of calcium sulfate in water is shown in Table 1. [0003] Table 1 Solubility of calcium sulfate at different temperatures [0004] [0005] It can be seen from Table 1 that the solubility of calcium sulfate in water is small, and there is an extreme value with the change of temperature. When the temperature is above 40°C, the solubility of calcium sulfate in water decreases with the increase of temperature. Therefore, in the heating tube, due to the high temperature of the tube wall, when the concentration of calcium ions and sulfate ions in the solution is high, it is easy to precipitate. [0006] In the salt making industry, especially after a certain pe...

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Problems solved by technology

However, the high-pressure water descaling method is not suitable for equipment with complex structures. For dense and hard scale layers, the water pressure is too low to meet the descaling requirements, and the use of higher water pressure has problems with the safety of the equipment. impact, the equipment may be damaged, which indirectly leads to an increase in cost

[0012] If the chemical descaling method is used, there is no relevant research report at present. The reason is that, on the one hand, there are the following technical problems: calcium sulfate is a strong acid salt. The pipe scale dissolution effect of the main salt-making equipment is poor. At the same time, since the heating pipe material is generally made of titanium or 2205DSS (that is, 2205 duplex stainless steel), especially titanium is prone to hydrogen embrittlement in acidic medium, so traditional pickling Dirt formula can not be suitable for solving this technical problem

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