Current application status of heat exchangers in petroleum refining and chemical manufacturing

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1. In oil refining and chemical manufacturing processes, the crude oils used are mostly sulfur-containing crude oils. Sulfur can react with oxygen and water in the air to produce sulfur dioxide and sulfur trioxide. These sulfurous compounds are highly corrosive; when they react with metals, they cause the metal structure to become porous and fragile, thereby reducing the performance and quality of the metal materials. For example, in the refining process, crude oil comes into contact with the top of various distillation columns; the sulfur content in the crude oil can cause corrosion at the top of these columns ； When crude oil passes through the condensation cooling system, corrosion is exacerbated by hydrogen sulfide, sulfur compounds, and water. Although many petroleum refining and chemical companies use materials such as Ni-P and carbon steel for manufacturing heat exchangers, corrosion-induced perforations still occur frequently, allowing crude oil to mix into the gasoline stream and thereby reducing production quality. 2. The operation of refining and chemical processing in catalytic cracking units relies on the support of these units. However, catalytic cracking equipment generates hydrogen sulfide and hydrogen chloride gases during production processes, and both of these gases can cause severe corrosion to the tubes in heat exchange equipment. Investigative analysis has revealed that the tube bundles of heat exchange equipment used in systems such as extraction, pre-hydrogenation, catalytic cracking, and reforming within the oil refining and chemical processing industries suffer from severe corrosion. 3. The hydrogenation units in hydrocracking plants are among the equipment where corrosion is a significant problem in petroleum refining and chemical manufacturing. This is mainly because NH4Cl and NH4HS can cause scaling inside the tube bundles, which in turn leads to electrochemical reactions that result in corrosion pits in these hydrocracking units. In the petroleum refining and chemical production process, the higher the sulfur content in high-sulfur crude oil, the greater the corrosive effect exerted by the hydrocracking unit on the tubes of the high-pressure air coolers. If the high-pressure air cooler tube bank is removed from the hydrocracking system, the levels of iron ions and hydrogen sulfide in the water samples from the high-pressure splitter and low-pressure classifier increase significantly.