ASMEU product - design example of compressed air storage tank

ASMEU product design example of a compressed air storage tank Xue Xiankun, Han Shouping, Wang Ying, Ma Wendou 2 (1. Jiaxing Meike Machinery Manufacturing Co., Ltd., Jiaxing, Zhejiang 314312) (2. Liaoning Fudi Heavy Industry Machinery Co., Ltd. Dalian Technical Points Company, Dalian 116023, Liaoning, China) The design of an ASMEU product, a compressed air storage tank, briefly describes the basic design methods and design issues of the ASME pressure vessel.

Pressure vessel; compressed air storage tank; ASME; design example 1 design parameters The basic design parameters of compressed air storage tank are as follows: design pressure: 1.0MPa; design temperature: 55 °C; operating pressure: S0.9MPa; operating temperature: 050 °C Medium: compressed air (non-fatal); minimum design metal temperature: -29C at 1.0MPa; maximum allowable working pressure: 1.0MPa at 55C; corrosion allowance: 1.5mm; weld coefficient 0.85; tank volume: 1.5 M3. Compressed air storage tank structure: Compressed air storage tank is composed of cylinder, two elliptical heads, one manhole and compressed air inlet and outlet; the inner diameter of the equipment is 1000mm; the cylinder and the head 2 are constructed and applied. Standard, technical conditions and drawing conditions CS1101-01 modified mark 0; assembly drawing No. DHJX1101-0 modified mark 0 3 Design basic steps 3.1 Calculate whether the tank volume meets the requirements of customer technical conditions Tank volume: V=2V head + V shell + V manhole = 1.521m3, customer requirements 1.5m3, to meet the requirements.

3.2 Shell minimum thickness calculation formula code: t-shell minimum thickness; S-maximum allowable stress value; R-shell inner radius; P-design pressure; E-welding joint coefficient; C-corrosion margin.

(1) Determine the hoop stress (longitudinal joint) (2) Determine the longitudinal stress (circular joint) 2 or P does not exceed 1.25 SE Formula: t 3.2.3 Circumferential stress is the control factor (4) for compressed air The minimum thickness of the housing of the device is 2.5 mm and does not include any corrosion allowance.

Foot requirements.

3.3 Minimum thickness calculation formula for elliptical head after forming: code: minimum required thickness of the head after t-forming; S-maximum allowable stress value; P-design pressure; E-welding joint coefficient; D-head straight section Inner diameter; inner radius of the spherical portion of the L-spherical or dish-shaped head; the L value of the elliptical head is found in Table UG-37.

(d) Accounting for the minimum thickness of the oval head after forming (b) requires that the thickness of the elliptical or dish-shaped head without tension is in any case not less than the thickness of the seamless hemispherical head divided by the head to shell The welded joint coefficient of the body. According to UG-32(f), when the thickness of the hemispherical head does not exceed 0.356L or P exceeds 0.665SE, ​​the following formula is adopted: t=PL/scientific engineer, engaged in pressure vessel design, process and quality assurance work.

(4) The minimum thickness of the head used for compressed air equipment is 2.5 mm, excluding any corrosion allowance. The thickness of the plate for the elliptical head is 12mm, and the thickness of the smallest head after forming is 10.6mm. 3.4 Accounting for the minimum thickness of the pipe diameter 3.4.1 According to the requirements of UG-45, for the access hole and the opening for inspection only Tug45=ta;tug45 is the minimum thickness of the pipe diameter, for other openings, tb=min, 3.4.2 according to the requirements of UG-45, calculate all the ta, tbi, tb2 (when external pressure), tb3 ta= UG-27 calculates the thickness plus the corrosion margin.

Tbi = take over the neck or other connecting piece to the container casing or head, assuming E = 1.0 takes into account the thickness required for the pressure and adds corrosion allowance.

Tb3 = the thickness found in Table UG-45 plus the corrosion margin.

3.5 Accounting for opening reinforcement 3.5.1 According to the requirements of UW-16, calculate the minimum requirements for connecting welds at the opening.

3.5.2 Reinforcement calculation (3) No reinforcement is required except for the structure itself. If it is consistent, no reinforcement calculation is needed. Otherwise, the reinforcement calculation is required according to the requirements of UG-36.

3.6 Hydraulic test 3.6.1 Hydraulic test temperature According to UG-99(h), in order to minimize the risk of brittle fracture, the metal temperature shall be maintained at 17 °C above the minimum design metal temperature during the hydraulic test, but shall not exceed 48. °C. 3.6.2 Hydraulic test pressure According to UG-99(b), the container designed according to internal pressure shall be at least one point equal to 1.3 times the maximum allowable working pressure and multiplied by the material stress ratio LSR during hydraulic test. (The ratio of the allowable stress value of the material at the test temperature to the allowable stress value at the design temperature).

The equipment is accounted for as follows: head and barrel 3.7 flange pressure temperature class used to calculate the material and grade of the tank flange (including the cover) SA-105M, carbon steel, level 150. According to Table 2 of ASMEB 16.5-2003, it is found that the maximum allowable working table pressure is 1.9 MPa at the design temperature of 55 C, and the design pressure of the storage tank is 1.0 MPa < 1.9 MPa. Therefore, the pressure temperature specification flange Meets the requirements of UG-11(a)(2) and UG-44.

3.8 Leg strength accounting and lifting ear strength calculations are not specified, and other design and construction details may be used with the approval of the inspector. Therefore, the legs and lifting lugs can be selected from standard parts approved by the inspector.

3.9 Heat treatment after cold forming 3.9.1 UCS-79(d) requires cold-formed carbon steel and low-alloy steel cylinder joints, heads and other pressure-bearing parts. When the maximum fiber elongation is 5% larger than the dairy state, Post-weld heat treatment.

3.9.2 Calculate the fiber elongation of each pressed part after molding according to UCS-79(d) formula.

Formula code: t-plate thickness; Rf - final centerline radius; R. - centerline radius before forming, (for plates, the value is infinite); 1.1858% < 5%, no post-weld heat treatment is required.

2.24% <5%, no post-weld heat treatment is required.

5.24%>5%, post-weld heat treatment is required.

3.10 Impact test can eliminate the impact test. If it cannot be waived, carry out the impact test in accordance with the requirements of UG-84.

3.11 Post-weld heat treatment According to the requirements of UCS-56, check whether all welds are subjected to post-weld heat treatment. The post-weld heat treatment thickness of SA-516MGr.485 material is 32mm. The maximum thickness of the weld of this equipment is 12mm, no post-weld heat treatment is required.

4 Problems that should be paid attention to in the design 4.1 Carbon steel forming Xue Xiankun and other ASME U products - Design examples of compressed air storage tanks 4.1.1 For carbon steel and low alloy steel, the following additional requirements are given in the specification: (1) Explosive forming is not allowed (2) If the material is subjected to post-weld heat treatment at the forging temperature, it is allowed to be formed by explosion; it must be certified in accordance with UCS-79.

4.1.2 Cold Formed Parts If the elongation caused by cold forming is greater than 5% and the following conditions exist, UCS-79 requires heat treatment after forming: (1) the container will be used for toxic medium; (2) the impact test is required. (4) Thickness reduction exceeds 10%; 4.2 Determination of minimum design metal temperature (MDMT) The ASME specification design uses the lowest metal temperature as the main design parameter. The minimum metal temperature is to determine whether the pressure component of the container and the welded test piece are One of the conditions for performing the impact test, so the designer must reasonably determine the minimum design metal temperature of the container. The minimum metal temperature should be determined by the following factors: (1) minimum operating temperature; (2) abnormal operation; (3) automatic cooling of the medium; (5) other refrigeration factors, except UG-20(f)(3).

4.3 Determination of design load The ASMEVI-1 volume lists the following types of loads, which must be considered in design: (1) internal or external pressure design pressure; (2) container and medium weight; (3) ancillary equipment Additional static load reaction generated by the weight; (5) cyclic and dynamic loads (eg fatigue considerations); (6) impact reaction forces, such as various abnormal pressures caused by explosions; (7) temperature gradients and different thermal expansions (8) Wind loads, snow loads and seismic loads, (considered if necessary).

The design rules provided by ASME VI-1 are only suitable for the calculation of pressure loads. For other loads, any applicable engineering method can be used.

5 Conclusion This article briefly introduces the basic method of ASMEVI-1 pressure vessel design and some problems that should be paid attention to in the design of compressed air storage tank. The basic design of the design steps is carried out in order to communicate with ASME designers. .

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