Alkaline cleaning agent and cleaning process for removing elemental mercury in natural gas separator

Abstract

The invention discloses a low-cost and non-polluting method for removing the residual paraffin in the separator, converting elemental mercury into a non-volatile compound, and avoiding corrosion of carbon steel and stainless steel. Mercury alkaline cleaning agent and cleaning process. The raw materials and weight percentages are as follows: at least two of sodium sulfide, sodium polysulfide and sodium thiosulfate, wherein sodium sulfide is 1-40%, sodium polysulfide is 0.1-15%, and sodium thiosulfate is 1-35%; At least one of sodium nitrate, sodium phosphate, and sodium sulfate, the content of which is 0.1-10%; one of sulfuric acid and phosphoric acid, the content of which is 0.1-15%; nonionic surfactant 0.5-20%; anionic surface active agent Active agent 0.5-10%; oxygen-containing solvent 0.5-15%; corrosion inhibitor 0.1-10%; water less than or equal to 90%; pH value greater than 10.0.

Description

Technical field: [0001] The invention relates to an alkaline cleaning agent for a natural gas separator, especially an alkaline cleaning agent that can completely remove residual paraffin in the separator, convert elemental mercury into a non-volatile compound, and avoid corrosion to carbon steel and stainless steel. A low-cost, pollution-free alkaline cleaning agent and a cleaning process for removing elemental mercury in a natural gas separator. Background technique: [0002] Because there will be a lot of wax and elemental mercury in the natural gas separator after a period of operation, it needs to be cleaned regularly or before comprehensive maintenance. The existing cleaning method is to add water to the natural gas separator and then heat it with steam, discharge the hot dissolved wax water and then purge it with nitrogen. Although part of the wax and elemental mercury can be discharged, there are still waxes and elemental mercury in the separator, and the concentrat...

AI Technical Summary

Problems solved by technology

Since mercury is volatile at room temperature, if grinding wheels, electric welding or plasma cutting are used during the maintenance process, the concentration of elemental mercury in the separator will increase sharply, and the maximum can exceed 0.1mg / L, which is much higher than the highest allowable elemental mercury in the working environment Concentration (0.04mg / L), which brings difficulties to the maintenance of the separator

Although the current method to deal with mercury pollution is to cover with sulfur, glycerin, 5% sodium sulfide or react with 20% ferric chloride solution and 10% bleach solution, this method is only limited to the laboratory, and the ceiling, wall, The air will be polluted, and it needs to be fumigated with heated iodine, which is very troublesome

Although substances that react with mercury include sodium thiosulfate and nitric acid, etc., the reaction speed of sodium thiosulfate is relatively slow, and it cannot be soaked for a long time due to the limitation of the maintenance time of the separator, so it cannot be used on the separator; nitric acid is strong acid , the corrosion of the reactor is large and difficult to control