Anti-corrosion and insulation measures for heavy oil storage tanks

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This post was last edited by huanghong on 2021-11-12 at 08:28. Anti-corrosion and insulation for storage tanks in the heavy oil tank area of the comprehensive utilization project for heavy oil. I. Instructions for preparation 1. Scope of application: These measures are applicable to the anti-corrosion and insulation work for storage tanks G-1101 and G1102 in the heavy oil tank area of the 400,000-ton/year comprehensive utilization project for heavy oil, which is part of the oil storage and transportation phase of this project. 2. Basis for preparation: 2.1 Current industry standards for construction and acceptance, as well as relevant technical documents. 2.2 Design and construction drawings for the oil storage and transportation phase of the 400,000-ton/year comprehensive utilization project for heavy oil. 3. Principles for preparation: The construction measures shall meet the requirements of systematic management for the 400,000-ton/year comprehensive utilization project for heavy oil by XX Group Co., Ltd., and shall serve as an important basis for planning and carrying out construction preparations step by step, as well as a guiding document for overseeing construction activities. 4. Project Overview: XX Group Co., Ltd.’s 400,000 tons/year heavy oil comprehensive utilization project – oil storage and transportation section, heavy oil tank farm and pump house – anti-corrosion and insulation works for storage tanks. 4.1 Quantities for the heavy oil tank area and pump house: 1 heavy oil tank (5000 M3) and 1 residue oil tank (5000 M3). 4.2 Anti-corrosion and insulation requirements for the tanks in the tank area: Anti-corrosion treatment for the outer walls of the heavy oil tanks, their roofs, and the railings on the ladder platforms – rust removal using a grinder followed by two coats of phenolic anti-rust primer ； The ladder platform railing is painted with two coats of primer and topcoat. External insulation for heavy oil tanks: Insulation hooks are installed on the tank walls and roof using φ4 cold-drawn steel bars, at a rate of 6 hooks per square meter ； The insulation support structure for the tank wall is made of -30x3 flat steel, arranged with a vertical spacing of 500 mm ； Horizontal spacing ≤ 400 mm ； And a circumferential support flat steel is installed at the lowest, middle, and highest positions of the tank body. After the insulation hooks and support rings have been manufactured and installed, rust removal and application of two coats of primer should be carried out promptly. The insulation material for the tank walls consists of two layers of rock wool boards, each 50 mm thick, resulting in a total thickness of 100 mm ； The protective layer is HJ10-130-90 profiled steel sheet with d=0.5mm ； Fix it with a core-pulling rivet of φ=4mm. The insulation material for the tank top is perlite insulation blocks with a diameter of 50 mm ； One layer of 10x10x0.9 galvanized wire mesh, with an asbestos-cement trowel coat having a thickness of 15 mm as the protective layer. Wrap with 2 layers of 0.5mm glass cloth, and apply alkyd enamel in three coats. 4.3 Basis for preparation and specifications: Construction drawings for the heavy oil storage and transportation section of XX Group Co., Ltd.’s 400,000 tons/year heavy oil comprehensive utilization project, namely the 5,000 m3 heavy oil tanks G-1101 and G-1102; drawing numbers: SBT-G013, SBT-G178. \"Grade of Rust on Steel Surfaces and Grade of Rust Removal before Painting\" GB8923; \"Code for Construction and Acceptance of Anti-corrosion Engineering for Industrial Equipment Piping\" HGJ229; \"Code for Construction and Acceptance of Insulation Engineering for Industrial Equipment and Piping\" GBJ126; \"Safety Regulations for Oil Refining and Chemical Engineering Construction\" HGJ233, SHJ505. 4.4 Timeline Requirements: Based on the characteristics of this project, the local climate conditions, and the actual volume of work on site, the time required for the anti-corrosion and insulation work on the two 5000m3 storage tanks is 20 days. II. Construction technical measures for anti-corrosion
1. Pre-construction preparation requirements
1.1 Materials, machinery and equipment, construction organization, and personnel must be in place according to the design requirements. 1.2 The raw materials come with certificates of conformity and test reports. 1.3 Submission of construction measures and improvement of rules and regulations. 1.4 The site meets the requirements for three connections and one leveling. 1.5 Complete design documents and technical documents, along with technical briefings for the review of construction drawings. 2. The quality grade of metal surface pretreatment shall comply with the following provisions: 2.1 For rust removal using manual or power tools, the quality grade of metal surface pretreatment shall be St3; the standards for rust removal quality shall meet those specified in \"Grade of Rust and Degree of Rust Removal on Steel Surfaces before Painting\" (GB8923). 2.2 The treated metal surface should be promptly coated with a primer. When the air humidity is high or the temperature of the workpiece is lower than the ambient temperature, heating measures should be taken to prevent the workpiece from being contaminated again or from rusting. Large-area surface pretreatment can be carried out in sections; once the metal surface has been properly treated, it should be coated with an undercoat immediately. 2.3 Requirements for raw materials: Paint must be ordered in accordance with the design specifications. Paint must not be stored outdoors; it needs to be kept under a cover in a well-ventilated and dry area. Fire safety measures must be observed, and it is prohibited to use expired paint. Outdoor work should be avoided on rainy days, as rain can affect the quality of the materials. 2.4 Construction measures: The scaffold for the outer wall of the storage tank should be a double-layer scaffold; a crossbar should be installed in the middle of each layer, and the height of each layer should not exceed 1.9 m. When transporting the material for the tank roof, a loading gantry should be set up first, and a conveying platform should be constructed on the tank roof. When carrying out rust removal for anti-corrosion treatment of tanks, painting can only be done after passing the standard inspections. Primer and topcoat should be used in accordance with the provisions of the design documents and the product instructions. The construction temperature should be between 15 and 30 degrees, with a relative humidity of less than 85%; the temperature of the surface to be coated should be 3 degrees higher than the dew point temperature. After completion, the coating must be left to dry naturally for at least 3 days and nights before it can be put into use. Construction and painting should not be carried out in windy, sandy, rainy, or snowy weather. Anti-corrosion coatings shall be applied in accordance with design requirements, including the number of layers, thickness, and application times, and must comply with the requirements of GJ229 or SHJ22 standards. When using the coating, it should be mixed thoroughly. The equipment used for preparing and applying the coating must remain clean, and mixing different types of equipment is not allowed ； If the base surface is uneven, has weld ripples, or is located at corners, putty compatible with the paint should be applied there; after it has been sanded and cleaned, the primer can be applied. The coating can be applied by brushing, rolling, spraying, or high-pressure airless spraying. When brushing on, the layers should overlap each other, with each layer being applied back and forth until it is evenly distributed ； During air spraying, the distance between the nozzle and the surface to be coated should be 50 mm–350 mm, at an angle of 70–80 degrees, with the air pressure ranging from 0.3–0.55 MPa. During high-pressure airless spraying, the pressure is 11.8–16.7 MPa, and the distance between the nozzle and the surface to be sprayed must be at least 400 mm. Brushing, rolling, and spraying should all be done evenly, with no areas left uncoated. The number of coating layers should meet the design requirements, and the top coat should be applied in the direction of the medium flow. The surface is smooth and even in color, with no real pores, bubbles, sagging, powdering, or damage. III. Technical measures for thermal insulation projects 1. Requirements for insulating materials 1.1 Insulation products and materials should possess flame resistance, expansion resistance, and moisture resistance; their technical specifications must meet the design requirements or instructions and be suitable for construction purposes. The chemical properties of insulating materials must be stable, and they must not be corrosive to metals. 1.2 The moisture barrier must have excellent waterproof and moisture-proof properties ； Resistant to atmospheric corrosion, biological attack, insect damage, and mold growth ； It must not cause corrosion or dissolution of other materials. It maintains integrity and stability under changes in temperature as well as in the presence of vibrations. 2. Protective layer materials should be non-flammable or flame-retardant ； It has a smooth, attractive appearance and is corrosion-resistant. It should be non-toxic, odorless, and easy to maintain. Galvanized iron sheet meets the requirements of the standard for \"Continuously Hot-Dip Galvanized Steel Sheets and Strips\". The specifications, diameter, and length of the insulation hooks must comply with the design requirements ； 3. Preparation before insulation: Before construction, the insulation materials and their products should be inspected; there are requirements regarding storage duration, as well as environmental conditions and temperature, and they must be stored in a classified manner. Install moisture-proof, water-proof, and impact-resistant facilities, and carry out this after the strength tests and airtightness tests are passed, as well as after the anti-corrosion construction is completed. Insulation layers, protective layers, and construction equipment for prefabricated products must be provided. 4. Construction of the insulation layer: When the thickness of the insulation layer is greater than 100 mm, it should be constructed in layers, with the thickness of each layer being similar to that of the adjacent layers. The seam width of the insulation layer should not exceed 5 mm; seams within the same layer as well as between adjacent layers should be offset from each other, with a lap length of no less than 50 mm. Insulation installation should be carried out from bottom to top, and it should be tied together in a circular or cross-shaped pattern using galvanized wire. The thickness and density of the insulation layer should be uniform, and its shape should be regular. After compaction and bundling, its bulk density must meet the requirements specified in the design. Each insulating layer shall be tied evenly with no fewer than two ties. After the insulation layer has been installed, the outer end of the hook nail should be bent and inserted into the insulation layer. 5. Construction of the protective layer: For the thermal insulation protective layer in this storage tank insulation project, HJ10-130-900 profiled sheets are used; the thickness of the galvanized iron sheet is 0.5 mm. The protective layer is secured using core-pulling rivets with a diameter of φ=4mm; one rivet is placed in each groove of the corrugated iron sheet, with no less than 4 rivets per seam. The rivets used to secure vertical joints are installed at intervals of 250 mm apart. For the metal protective casing of the tank insulation layer, profiled sheets should be used, and it should be circumferentially reinforced with -30x3 flat steel metal bands. 6. The protective layer of the equipment should be installed from bottom to top, with the joint overlap dimension being 30–50 mm; a slope as specified in the design should be provided on the top of flat-roofed equipment. It is strictly prohibited to step on or place items on the already applied protective layer. A rainproof cover should be provided for the protective layer on the equipment nameplate. 7. The allowable deviation for rock wool semi-rigid boards is +10% to -5%. The metal protective layer shall have no loosening, flanging, notches, or obvious dents; the joints should be parallel or perpendicular to each other, and the ellipticity shall not exceed 10 millimeters. IV. Quality Assurance Measures Quality inspection personnel should attend the drawing review sessions organized by the project management department, focusing on verifying the consistency between the quality standards adopted and the requirements specified in the design specifications. They should also participate in the discussions regarding the construction organization plan and construction methods, in order to assess the feasibility and effectiveness of the quality assurance measures employed. Establish a quality assurance system composed of quality assurance engineers and full-time or part-time quality inspectors from the construction team, and ensure its proper operation. Strictly implement quality supervision procedures, and ensure the conduct of three levels of quality inspections: self-inspection, mutual inspection, and specialized inspection. Quality supervision is carried out in accordance with the quality inspection and control system established by the construction unit’s quality inspection station. 1. Quality management during the construction preparation phase: (1) Thoroughly carry out drawing reviews to understand the design intent and specifications, identify issues present in the design documents, and keep proper records of these reviews. (2) Prepare construction technical documents such as construction measures or work instructions. The document must specify the construction procedures as well as the quality inspection standards and requirements for the process. (3) Based on the specific conditions and requirements of the project, formulate and implement a technical training and assessment plan for construction workers; those who are required to work with certificates must obtain the corresponding qualification certificates. (4) The construction equipment used shall meet the requirements of the construction process and be in good condition. (5) Projects that have not undergone drawing review, for which no construction technical documents have been prepared, or for which no technical instructions have been given shall not commence work. 2. Quality management during construction (1) It is necessary to carry out proper quality inspection and supervision of the materials, finished products, and semi-finished products used in the project. The Equipment and Materials Department is responsible for verifying the specifications, quantity, quality, and certificates of conformity of the received materials. At the time of delivery, a copy of the certificate of conformity shall be provided to the user unit together with the materials. Materials whose certificates do not match the actual items, those without certificates, or those that require re-inspection but have not undergone such inspection should not be accepted into storage, let alone issued for use. Those that fail the inspection must be clearly marked and dealt with separately. (2) During the construction process, it is necessary to establish proper records for the storage and distribution of raw materials and other items, in order to prevent confusion, rusting, deformation, deterioration, damage, and incorrect distribution of these materials. (3) During the construction process, all the company’s quality inspection management systems must be strictly followed to identify and address any issues that arise in a timely manner. (4) All construction technical documents should be recorded, collected, and organized at all times, and must keep pace with the construction progress. (5) During concurrent construction operations, civilized construction must be properly implemented. The subsequent process should pay attention to protecting the results achieved by the preceding process, so as to ensure the overall quality of the project. (6) Strictly implement the quality veto system and hold regular quality meetings. (7) Organize regular quality inspections as needed, summarize quality management efforts, overcome common quality issues, and improve construction quality. The results of the comprehensive quality inspection should be communicated to the relevant units so that timely corrective actions can be taken, and they should also be reported in writing. 3. Quality management before and after completion (1) Carry out the “three inspections and four determinations” prior to completion: check for missing items, potential hazards, and quality issues ； After identifying the problem, determine responsibilities, implement measures, assign workers, and set a completion deadline. (2) Before the project is handed over, each specialty and each construction team shall classify, organize, and consolidate the technical documents required for handover archiving, and file them uniformly. (3) After the project is put into use, the relevant departments should organize follow-up visits to the project to seek users’ opinions on the project quality. 4. On-site inspection quality management: (1) To ensure the quality of the project, qualified inspection personnel with the appropriate numbers are assigned on-site as required by the project, to carry out inspections of equipment, materials, and products (with physical and chemical tests being conducted by the quality inspection centers of specialized testing companies). For all materials, equipment, finished products, semi-finished products, etc., that require testing, a designated person shall be responsible for providing suitable samples and carefully filling out the commission form in accordance with the requirements of the testing procedures. (3) The entrusted recipient shall promptly verify the contents of the assignment and the physical items, check whether the samples are qualified, and arrange for testing in a timely manner. (4) During the testing process, the testing standards must be strictly followed, operating procedures must be adhered to, and all original records must be kept properly. The test report shall be signed by the operator and reviewed by a qualified professional. (5) Diligently carry out the maintenance, upkeep, and periodic calibration of testing instruments and equipment to ensure they are always in good working condition. Properly archive and store documents such as test reports for future reference. V. Safety, Health, and Environmental Protection Measures 1. Safety and civilized construction measures: Thoroughly implement the principle of \"safety first, prevention foremost\". Strictly enforce the Chemical Safety Regulations. Workers involved in construction must strictly adhere to safety regulations; when working at heights, they must wear safety belts and anti-slip shoes. Tools and parts used for working at heights should be placed securely to prevent them from falling and causing injury. Fire-fighting equipment must be provided at the construction site. Before entering the site, workers must receive safety and technical instructions from the owner’s safety management department and strictly comply with the owner’s regulations regarding safety management. Familiarity with safety technical operating procedures is required. Upon entering the site, wear the necessary protective equipment as required by each type of work. Sufficient lighting equipment should be available for night construction. Mechanical and electrical equipment must be operated by persons familiar with its performance; unqualified personnel are not allowed to install, disassemble, or maintain such equipment. Various electrical devices should be equipped with dedicated switch sockets, and leakage protectors should be installed on the power supply side. Switch sockets used outdoors should be placed in waterproof boxes; no miscellaneous items are allowed to be stored inside these boxes, and the doors should be locked. The power supply should be turned off when not in use. The construction site should maintain civilized construction practices, with materials stored in designated areas as required. Painting operations are strictly prohibited in conditions of snow, fog, strong winds, or a relative humidity greater than 85%. Outdoor insulation work should be carried out on days without rain, fog, or strong winds. 2. Health measures: Different personal protective equipment should be provided according to the type of construction work. Insulation workers should wear masks properly while carrying out insulation work. Regular health checks are conducted for employees. Heat prevention and cooling measures should be taken during the summer. 3. Environmental protection measures: Efforts should be made on-site to minimize the presence of floating insulation fiber debris. On-site equipment reduces noise to <75 decibels during the day and <55 decibels at night. Paints and fire-retardant coatings must not be discarded carelessly to protect the environment. Anti-corrosion and insulation of storage tanks in the heavy oil tank area of the heavy oil comprehensive utilization project