Pressure vessel installation process

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During the pressure vessel installation process, the workers involved in the construction (crane operators, welders, electricians) must hold valid certificates to work. All personnel participating in the pressure vessel installation must be familiar with this procedure as well as the relevant drawings and specifications. Prerequisite 1: The technical documents and construction drawings are complete, and the construction supervisors and technical personnel have provided the workers with instructions regarding these drawings ； The construction workers are familiar with the content of the construction drawings. The construction workers are familiar with the construction procedures. The construction record form is available. Provide written notification to the local special equipment safety supervision and management department prior to construction; construction can proceed once the notification has been given. 2. Essential conditions for the working environment: the civil engineering foundation meets the required standards, has passed inspection and approval, the handover procedures for the foundation have been completed, the underground works in the vicinity of the foundation are finished, and the site is leveled and hardened. The temporary roads for construction transportation have been repaired to ensure smooth logistics. The lighting, electrical equipment, and materials required for construction are all available and meet the construction requirements. The lifting equipment for installation has arrived. 3. Construction preparation: Familiarize oneself with the drawings and relevant documents, master the technical parameters of the equipment as well as the installation requirements, and understand the environmental conditions for equipment installation ； Determine technical measures and construction methods in accordance with the construction procedures ； Conduct safety technical briefings for construction workers involved in the installation of pressure vessels, to ensure that the installation complies with regulatory requirements and construction safety standards ； Based on the construction drawings and technical plans, prepare various tools, machinery, and materials for installation ； According to the construction plan, before installation work begins, the equipment transportation route should be checked, and the construction site must meet the conditions required for equipment installation. Intermediate handover certificate must be obtained for pressure vessel foundations before they are put into use ； The base centerline, elevation marks, and other markings are complete and clear; the bolt length meets the technical requirements ； Equipment unpacking and inspection: 1. Before the equipment is installed in place, it is necessary to submit an application for approval to start the installation of pressure vessels, with such approval being granted by the local technical quality supervision authority. The equipment unpacking and inspection is organized by the project owner, with the participation of the supervision unit and the construction unit in carrying out this inspection ； 2. Technical documents and materials: Copies of the manufacturer’s qualification certificate for pressure vessel production, certificates of supervision and inspection regarding the safety performance of boiler and pressure vessel products, product quality certificates for pressure vessels, general layout diagrams of the pressure vessel equipment, detailed drawings of the vessel itself, technical specification tables, as well as completion drawings – all of which must be complete and in compliance with relevant standards ； 3. Equipment acceptance: The names, specifications, models, and quantities of the equipment and spare parts meet the design requirements and are consistent with the packing list ； The external dimensions and the orientation of the pipe openings match those shown in the equipment diagram ； Visual inspection reveals no damage, deformation, rust, etc.; the quality is satisfactory. 4. Handover: After the equipment passes the acceptance inspection, the handover procedures shall be carried out. 5. Equipment storage: After unpacking, equipment should be properly stored to prevent corrosion, damage, loss, etc. Openings such as nozzles and manholes should be sealed. Equipment placement 1. Preparatory work before equipment installation: Before installation, the installation reference lines and positioning marks should be marked in accordance with the requirements of the design drawings or technical documents ； For devices that are interconnected or linked to each other, a common benchmark should also be established in accordance with the requirements of such interconnection or linkage. Before installation, the equipment’s foundation bolts should be inspected to ensure there is no damage or rust ； Check the orientation marks, center of gravity marks, and lifting points of the equipment; those that do not meet the installation requirements should be corrected. Check the position and dimensions of the equipment’s foundation bolt holes and the pre-installed bolts in the foundation. 2. For equipment foundations that require secondary grouting for proper treatment, the surface should be roughened; the depth of these rough spots should generally be no less than 10 mm, with a density of 3 to 5 spots per square decimeter being appropriate. The area where shims are to be placed should be leveled, with a levelness deviation of less than 2 mm/m. For the foundation of cold exchange equipment with sliding ends, the horizontal deviation of the embedded steel plates at those sliding ends should not exceed 1 mm/m. The surface before installation must be cleaned thoroughly, and butter should be applied to the sliding surfaces in contact with the equipment base. 3. Shims: Shims should be placed on both sides of the foundation bolts. Wedge shims must be used in pairs, with an overlap length of not less than 3/4 of their total length. The depth to which the shim set extends into the bottom surface of the equipment base should exceed the center of the equipment’s foundation bolts; after leveling, these shims should be secured in place using spot welding before grouting is applied ； The distance between adjacent shim sets should be around 500 mm. The number of shims in each set should be kept as low as possible, with no more than 5 shims per set; thin shims should not be used ； The surface of the shims is flat, free of oxide scale, burrs, etc ； 4. For lifting and positioning the equipment, determine its installation direction based on the process piping layout diagram, and then use lifting equipment to position it in place. The alignment and leveling of the equipment should be carried out by adjusting and measuring based on the reference lines on the foundation (center marks, level marks) in relation to the reference points on the equipment. Alignment should be carried out in two directions that are perpendicular to each other within the same plane. When leveling the equipment, shims should be used for adjustment as required ； Adjustments should not be made by tightening or loosening anchor bolts or applying local pressure. After alignment or leveling is completed, tighten the foot bolts and weld the shims together. For vertical equipment with a height of over 20 meters, in order to avoid the influence of weather conditions, the adjustment and measurement of its verticality should not be carried out when one side is exposed to sunlight or when the wind speed exceeds level 4. For horizontal equipment that is subject to expansion and contraction, check the expansion allowance at the sliding end; loosen the nuts of the foot bolts at the sliding end by 1~3 mm, and then secure them with lock nuts. For horizontal equipment equipped with a sliding base, the bottom of the support should be cleaned and lubricated. Pressure testing: 1. The pressure testing of equipment and equipment connected by main flanges shall be carried out in accordance with the following provisions: If the equipment has already undergone pressure testing at the manufacturer’s facility, and is accompanied by complete quality certification documents as well as a supervision inspection certificate issued by the local boiler and pressure vessel regulatory authority, and if it has not suffered any damage or deformation during transportation, with a production date not exceeding six months, then it is not necessary to conduct another pressure testing upon installation ； After the equipment has undergone pressure testing at the manufacturing plant, and for equipment protected by a gas seal, if it is confirmed by the construction party or the supervision party that the gas seal is in good condition prior to installation, there is no need to conduct another pressure test ； The equipment has undergone pressure testing at the time of manufacture; however, in the event of damage during transportation, the project owner, the supervision unit, and the construction unit shall negotiate to conduct a retest of the pressure testing ； Equipment assembled at the construction site shall undergo pressure testing ； When the contract provides provisions, those provisions shall be followed. The pressure test is subject to on-site supervision and inspection by the local quality and technical supervision department as well as the supervision unit. 2. The items and requirements for the pressure test of equipment shall be carried out in accordance with the provisions of the design drawings or design documents. 3. For equipment that does not allow for any trace amounts of residual liquid, or that cannot be filled with liquid due to its structure or supports, a pneumatic test can be used. 4. For pressure testing, two pressure gauges with the same range, which have been calibrated and are still within their validity period, must be used. The range of the pressure gauge should be twice the experimental pressure, but it must not be less than 1.5 times nor more than 3 times that value. The accuracy level must be at least 1.5, and the diameter of the dial must be no less than 100 mm. 5. Pressure gauges should be installed at the highest and lowest points of the equipment ； The test pressure value shall be based on the gauge reading at the highest point, and verified using the gauge reading at the lowest point. 6. Before pressure testing, the equipment should be inspected visually; its surface must remain dry to facilitate the detection of leaks. Precautions 1. The rust and dirt on the bolts should be removed completely, and the threaded parts should be coated with grease after the rust is cleared. 2. Safety precautions should be taken when installing equipment with coils. 3. Special attention should be paid when installing equipment for heat treatment: (1) During acceptance, the shims, insulation support rings, and insulation nails on the equipment must be carefully checked to ensure they match the specifications in the drawings. (2) Lighting a fire on the equipment is strictly prohibited during its installation. (3) Check whether the welding cable is exposed, to prevent arcing on the equipment as the cable is dragged. (4) The area where welding is to be carried out should have clear markings. 4. The center position for installing the equipment should be based on the center line of the foundation ； 5. The verticality of vertical equipment is determined based on measurement points at both ends of the equipment; it is measured at a 90° angle using a magnetic plumb bob in conjunction with a steel ruler, ensuring proper vertical installation. 6. The levelness of horizontal equipment should be measured with reference to the equipment’s centerline using a glass tube, with the levelness of the alignment flange serving as a reference. 7. The oval holes in the sliding end supports of horizontal equipment, as well as the position of the foundation bolts, must meet the expansion and contraction requirements under operating conditions; the support plate should be able to slide relative to the base plate. After the piping for the equipment is installed, the foundation bolts should be loosened to create a gap of 1–3 mm. 8. After the equipment shims have been adjusted properly, they must be inspected and approved by the construction unit and the supervision company; only after approval can a record of the work done be created, allowing for secondary grouting to proceed.