Treatment method by taking seawater as coal gasification cooling water

Abstract

The present invention relates to a treatment method by taking seawater as coal gasification cooling water. The treatment method comprises: seawater pretreatment and seawater circulation; when the seawater is circulated as circulating cooling water, adding 40-50 mg of a corrosion inhibitor, 30-40 mg of a scale inhibitor, 20-30 mg of oxidizing biocides, and 80-120 mg of non-oxidizing biocides in per liter of the seawater. According to the technical solution of water treatment provided by the present invention, the concentration factor can be controlled between 1.5-2.0. The corrosion rate of carbon-steel is less than 0.125 mm / a, the corrosion rate of copper, stainless steel is less than 0.009 mm / a, the biological slime is less than 4.0 mL / m3, a total number of heterotrophic bacterium is less than 5.0x105 / mL, and the fouling thermal resistance is less than 3.44x10-4m3.k / w. The treatment method meets the provision of (People's Republic of China national standard industrial circulating cooling water treatment design specifications) GB50050-95, water saving reaches 97% with respect to once-through cooling.

Description

technical field [0001] The invention relates to a method for treating seawater as cooling water for coal gasification, and more specifically relates to a corrosion inhibitor, scale inhibitor, biocide and a treatment scheme for seawater used as cooling water. Background technique [0002] At present, many industrial enterprises in coastal areas at home and abroad have used seawater instead of fresh water as industrial cooling water, but the cooling method has always been the direct-current water supply method, and the heat exchanger is made of titanium, and the pipeline is lined with anti-corrosion materials. , and the discharge of a large amount of hot water has caused heat pollution to offshore waters. Therefore, the cooling water of large and medium-sized industrial enterprises in coastal areas uses seawater as supplementary water, and chooses a circulating cooling water system with cooling towers, which not only avoids a large amount of hot water being discharged into the...

AI Technical Summary

Problems solved by technology

[0003] Due to the extremely high salinity of seawater, containing high hardness, high chloride ions, high sulfate ions and high dissolved solids, it has strong corrosion and fouling properties on equipment. The water pipeline will be severely corroded, scaled, and; seawater contains a variety of microorganisms, shellfish, hydroids, etc. When the circulating water runs and reproduces seriously, the pollution and shellfish themselves are easy to block equipment and other problems; in addition, offshore areas The high suspended matter in seawater will promote the growth of microorganisms and form slime, which is easy to adhere to the inner wall of cooling equipment and water pipelines in the circulating cooling water system, and is easy to block in serious cases