| This paper aims at the problems of corrosion and scaling in glycol dehydration unit of natural gas shallow refrigeration plant of Daqing Oilfield Natural Gas Company and therefore relevant anticorrosion and antiscale technology is studied. After a detailed studying the quality degrading rule and properties change rule, such as acidity, chroma and turbidity, of glycol being used in plant, and component analyzing of corrosion products generated from plant in operation, we get the conclusion that corrosion products are the sediments from corroded equipment which increase with the acidity of glycol, that the acidification of glycol is caused by glycol's absorption of sour gas hydrogen sulfide when contacting natural gas, and that the black sediments are acid-insoluble gel kind substance and corroded products by hydrogen sulfide and/or oxygen. Formula of corrosion inhibitor is to be developed according to the property change rule of glycol and formation mechanism of corroded products. After studying of dosage and corrosion inhibiting effect of using single or mixed MEA, DEA, TEA and MDEA, we get the optimized formula of corrosion inhibitor, which is a mixture of TEA and MDEA with specified proportion. A field test of lab achievement has been fulfilled in Zhongqi shallow refrigeration plant. Analysis of data got from field test validates the effectiveness of the corrosion inhibitor with optimized formula; thus an effective way to abate the corrosion problems in glycol dehydration unit of natural gas shallow refrigeration plant is available. |
