Special lining for equipment

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I. Classification and structural forms of equipment-specific linings (1) Classification In the petrochemical production process, certain equipment or pipelines such as catalytic cracking reactors, regenerator flue gas pipes, single-acting slide valves, double-acting slide valves, waste heat boilers, and cold-wall hydrogenation reactors require insulation concrete or heat-insulating and wear-resistant concrete linings to be applied to their inner walls. This is done in order to prevent corrosion of the metal walls caused by high-temperature media, wear of the inner surfaces and components due to fast-flowing catalysts, as well as to meet insulation requirements. These are what are known as equipment-specific linings. Equipment-specific linings can be classified according to their functions into high-wear-resistant types, wear-resistant types, heat-insulating and wear-resistant types, and heat-insulating types of linings ； Based on the lining anchoring method, it can be divided into structural steel fiber reinforced linings without mesh grids and structural linings with mesh grids. The main materials used in lining preparation include ceramsite, expanded perlite, vermiculite, bauxite clinker, corundum (white corundum, brown corundum), stainless steel fibers, etc. (II) Structural form The structural forms of the specialized linings for such equipment include: steel fiber-reinforced single-layer heat-insulating and wear-resistant lining without a turtle-shell mesh structure, and double-layer heat-insulating and wear-resistant lining ； Thermal-insulating and wear-resistant double-layer lining with tortoise-shell mesh structure ； High-wear-resistant single-layer lining with tortoiseshell mesh structure, and heat-insulating high-wear-resistant double-layer lining. The thickness of the single-layer wear-resistant lining with a tortoise-shell mesh structure is 20 mm or 25 mm, while the thickness of those without such a mesh structure is not less than 60 mm. A single-layer or double-layer insulated and wear-resistant lining, with a total thickness of generally 100–150 mm. For the double-layer insulated and wear-resistant lining, the thickness of the wear-resistant layer is 26 mm or 31 mm, with the remaining part being the insulation layer. There are two methods for fixing the lining: tortoise shell mesh anchoring and anchor bolt anchoring. The types of anchor pins include columnar, V-shaped, Y-shaped, Ω-shaped, S-shaped, etc. Y-shaped anchor pins are used only for irregularly shaped components (such as air distribution rings) that employ a highly wear-resistant single-layer lining and for which it is not appropriate to use turtle-shell mesh. In accordance with the provisions of the \"Technical Specifications for Insulated and Wear-Resistant Concrete Linings,\" the lining structures used for general equipment and pipelines include: 1. For the regenerators, coking tanks, three-stage cyclone separators, external heat exchanger shells in catalytic cracking units, as well as containers and pipelines under similar operating conditions, a steel fiber-reinforced single-layer lining without a turtle-shell mesh structure, or a double-layer insulated and wear-resistant lining applied in certain areas, is recommended ； 2. The reactor (settler) can be equipped with a single-layer lining reinforced with steel fiber without a grid structure, or with a double-layer lining featuring a grid structure for heat insulation and wear resistance ； 3. The lift pipes and inclined tubes of the catalytic unit should be equipped with a double-layer lining made of a tortoise-shell mesh structure, which provides thermal insulation and wear resistance ； 4. Cyclone separators designed with cold walls, flue gas orifice plate pressure reducers, pipe sections following double-acting slide valves, as well as vessels and pipelines with similar operating conditions, should employ a heat-insulating and highly wear-resistant double-layer lining with a tortoise-shell mesh structure ； 5. Hot-wall cyclone separators, coarse cyclones, dilute-phase tubes, leg sections that are severely worn due to medium erosion, and similar components under similar operating conditions should be equipped with a highly wear-resistant single-layer lining featuring a tortoise-shell mesh structure. II. Construction techniques, inspection methods, and performance (1) Construction techniques for equipment-specific linings The construction techniques for equipment-specific linings include the pouring method (vibration method), spraying method, and coating method. The pouring method is suitable for the construction of single and double-layer heat-insulating and wear-resistant linings without a turtle-shell mesh ； The spraying method is suitable for equipment and pipelines with a diameter greater than 2 m ； The coating method is suitable for the segmented rotation construction of horizontal equipment, the inclined sections of vertical equipment at angles less than 45°, as well as other lining constructions under restricted conditions. After pouring, spraying, or applying the lining, it shall be heat-treated in accordance with the heat treatment procedures specified in the \"Technical Specifications for Insulated and Wear-Resistant Concrete Linings\". (II) Inspection and testing of specialized linings for equipment 1. Pre-lining inspection: The lining material shall meet the grade specified in the design requirements, and it must come with a factory certification of conformity ； Quality inspection of equipment casing sandblasting for rust removal, anchor bolts, and other lining accessories. 2. Liner installation inspection: Check the mixing of the lining material with water, and verify that the container is clean and that the water used for construction is of suitable quality ； Inspect the construction progress to ensure proper construction methods and the specified thickness ； Check whether appropriate measures and drying temperatures were used for curing and drying the lining; verify if there are any voids in the lining after curing, and inspect the lining for cracks and peeling after drying. 3. Post-lining inspection: Check for the removal of defective linings and the situation regarding re-lining, ensuring that the re-lining method and the performance of the lining meet the required standards ； Check the quality records for each stage, etc ； Construction companies should compile various records and test reports and provide them to the client.