1. Saturated tower structure
The structure of the saturated hot water tower is a packed tower, the cylinder is made of 16 manganese steel, the packing support frame and ten swirl plates are made of 304 stainless steel, the top hot water spray pipe in the saturated tower is made of carbon steel, and the stainless steel wire filter The material is 321 stainless steel. After the saturated hot water tower was put into use, the temperature of the upper section of the intermediate conversion furnace dropped sharply. After the semi-water gas came out of the saturated tower, water entered the intermediate conversion furnace, causing the furnace temperature to drop. During inspection, it was found that the saturated hot water spray pipe was severely corroded, and the stainless steel wire filter at the top of the tower was The mesh was also severely corroded, with some holes in the mesh being corroded.
2. Causes of corrosion of saturated tower
Since the oxygen content in the saturated tower is higher than that in the hot water tower, although the absolute content of oxygen in the semi-water gas is not high, the corrosion process of carbon steel in aqueous solution is mainly the depolarization of oxygen, which depends on the temperature and pressure. When both are higher, the depolarization effect of oxygen is greater. The chloride ion content in the aqueous solution is also an important factor in corrosion. Since chloride ions can easily destroy the protective film on the metal surface and activate the metal surface, when the concentration reaches a certain value, the stainless steel will not be resistant to corrosion. This is also the reason for the stainless steel wire at the top of the saturated tower. The filter was severely corroded. Fluctuations in operating pressure and frequent sudden rises and falls in temperature subject equipment, pipes, and fittings to alternating pressures, which can cause fatigue corrosion.
3. Anti-corrosion measures for saturated tower
① During the gas production process, strictly control the sulfur content in the semi-water gas to keep the content as low as possible. At the same time, control the desulfurization function to ensure that the sulfur content in the semi-water gas after desulfurization is low.
② The circulating hot water uses desalted soft water to control the quality of the circulating hot water, analyze the value of the circulating hot water on a regular basis, and add a certain amount of ammonia water to the circulating hot water to increase the value of the water.
③ Strengthen diversion and drainage, promptly drain the sewage deposited in the system, and replenish fresh desalinated soft water.
④ Replace the hot water spray pipe material of the saturation tower with 304 and the stainless steel wire filter material with 304 to extend its service life and ensure long-term operation of the system.
⑤ Use anti-corrosion coating. Due to the high pressure change pressure and corresponding temperature, inorganic zinc-rich paint should be used because it has good water resistance, is not afraid of ion intrusion, has high heat resistance, is cheap, and is simple to construct.