A method of manufacturing sections air cooler

 

The invention relates to the field of power engineering and can be used in the manufacture of air cooling units, mainly used in chemical and gas processing industries. Two beam pipes tightly connected to tube sheet weld chamber having a back wall with holes tube, coaxially with the holes of the lattice. Between the beams, pipes set the internal Central partition. In the last perform pre-holes for passage of the working fluid. The total flow section of these holes should be not less than the total flow section of the same beam pipe. For the manufacture of structural elements partitions use the material, resistant to stress corrosion cracking when working in corrosive environments, such as fluids containing hydrogen sulfide environment. As this material can be used carbon steel, the characteristics of which can be chosen according to the following conditions impurities and nonmetallic inclusions. The result is increased durability of the obtained partitions and security when using them. 3 C.p. f-crystals, 2 Il.

Known technical solution, according to which in the manufacture of sections of air cooling units can be used as a bundle of tubes with different cross-sections [1].

Known technical solution allows to choose the most effective flow section of the pipe, however, is not the problem of the reliability of a design at work in aggressive environments.

Known technical solution, which is aimed at solving the problem of increasing the reliability of the sections of the air cooler in aggressive environments, in which a set of tubular elements in a grid sealed chamber, while the use of composite design of tubular elements, each of which are in the form of two tubes connected between a guaranteed interference [2].

The use of the known technical solutions in the industry is costly due to the complexity of manufacturing technology - when used in tubular elements of the two tubes to be joined with tension, as well as the use of alloyed steels or non-ferrous metals to perform one of them.

There is a method of manufacturing sections of the air cooler in which drscheme under the tube, made of coaxial holes of the grid, set the internal Central partition between the two beam pipes, which have symmetrically with respect to the internal Central partition, in the last perform pre-holes for passage of the working fluid with reduced total cross-section is not less than the total flow section of the same beam pipe [3 - prototype].

The material used for the manufacture of sections of an air cooler is economically justified when working in a relatively non-aggressive environments. However, in servodidio - and hydrogen-containing environment, the material used has a low resistance to corrosion degradation, low life and high risk of accidents with release of toxic products.

The propensity for corrosion degradation of low alloy steels in environments that cause saturation with hydrogen, is determined by the presence of impurities, and especially their educated non-metallic inclusions and clusters. In particular, used in the prototype material permits the presence of impurity content: sulfur is not more than 0.040% for and phosphorus - not more than 0.035% of. With regard to non-metallic inclusions, their content in common (the ratio of the longitudinal and transverse dimensions of which exceeds 2/1), are the centers of origin of the cracks that develop under the action of hydrogen, which reduces the security and reduces the life of the unit as a whole.

The present invention is directed to solving the problems of improving industrial security and accordingly the durability of the sections of the air cooling, while ensuring efficiency by optimizing design performance and requirements for the selection of materials to ensure the best condition of all structural members when working in corrosive environments below a threshold level, causing stress corrosion cracking of materials, ensuring maximum monitoring the condition of structural elements through appropriate design changes.

Specified single technical result is achieved that implements a method of manufacturing sections of the air cooling unit, in which two beam pipes is sealed by expanding connected to tube sheet weld chamber having a back wall with holes for tubes made of coaxial holes of the grid, set the internal Central partition between the two beam pipes, which have symmetrically with respect vnutrinomernye reduced cross-section not less than the total flow section of the same beam pipe, and structural elements are made of materials that are resistant to stress corrosion cracking when working in corrosive environments, such as fluids containing hydrogen sulfide environment in which the material of the structural elements are made of carbon steels, the characteristics of which are selected from conditions impurity content:

Sulfur is Not more 0,0065%

Phosphorus does Not exceed 0.025%

Nonmetallic inclusions, points:

Sulfides “With” Not more than 2,0

Oxides strachocina “OS” Not more than 2.5

Silicates fragile “CX” Not more than 2.5

Sheet metal for the manufacture of tube and the rear wall with the holes of the tube is chosen from the condition that the size of the area of each region of the accumulation of non-metallic inclusions did not exceed 20% of the size of the area running holes, and the size of the total area of clusters of non-metallic inclusions did not exceed 0.5% of the total area of the holes.

In addition, the distance between the two beam pipes is chosen from the condition

l11,5 d1,

where l1- the distance between the axes of the outermost holes of the lattice included in the corresponding group;

d1- the diameter of the holes in the lattice under labour the shaft with the location of the major axis perpendicular to the plane of the positioning tube and the rear wall welded camera, the distance between the edges of the holes are within

l1/d2min=1,5-2,0,

where l2- the distance between the edges of the oval holes between them.

d2min- minor axis of the oval hole,

and the distance between the edges of the oval holes and grille or rear wall welded camera choose within

l3Sn=1,5-2,0,

where l3- the distance between the edges of the oval holes and walls weld cameras;

Sn- the thickness of a partition.

Conducted by the applicant's analysis of the prior art, including searching by the patent and scientific and technical information sources and identify sources that contain information about the counterpart object method, has allowed to establish that the applicant is not detected analogues characterized by signs, identical to all the essential characteristics for the requested method.

The definition from the list of identified unique prototype as the most similar in essential features allows to identify a set of essential towards perceived by the applicant unified technical result of the distinctive features for the declared object contained in the formula of the legislation.

To verify compliance of the claimed invention to the requirement of inventive step, the applicant conducted an additional search of the known solutions in order to identify characteristics that match the distinctive features of the selected prototype signs for the declared object of the invention, the results of which show that the claimed invention is not necessary for the expert in the obvious way from the prior art.

Therefore, the claimed invention meets the requirement of “inventive step” by applicable law.

An example of structural embodiment of an air cooler on the proposed method are shown in figures 1-2, where Fig.1 - shows a General view of an air cooler of Fig.2 is a view along arrow a in Fig.1.

Air cooler comprises a base 1, a welding chamber 2, which includes a tubular bars 3 and rear wall 4. Tubular bars 3 are rigidly connected to the two beam pipes 5 by expanding the latter, and the rear wall are aligned pipes 5 processing tube 6. In the case of welded camera 2 is the internal Central partition 7 with an oval through holes 8.

Structural elements perform oradatabase environment, moreover, the material of the structural elements are made of carbon steels, the characteristics of which are selected from conditions impurity content:

Sulfur is Not more 0,0065%

Phosphorus does Not exceed 0.025%

Nonmetallic inclusions, points:

Sulfides “With” Not more than 2,0

Oxides strachocina “OS” Not more than 2.5

Silicates fragile “CX” Not more than 2.5

Sheet metal for the manufacture of tube 3 and rear wall 4 holes tube 6 is chosen from the condition that the size of the area of each region of the accumulation of non-metallic inclusions did not exceed 20% of the size of the area running holes, and the size of the total area of clusters of non-metallic inclusions did not exceed 0.5% of the total area of the holes.

To ensure the reduction of stress concentration and additional reducing conditions the nucleation of cracks the distance between the two groups of the tube bundle 5 (Fig.1) choose from the condition l11,5 d1where l1- the distance between the axes of the extreme holes 8 of the tube 3, included in the corresponding group, d1- the diameter of the holes 8 in the tube lattice 3 led tubes 5 of the bundle and the tubes 6 in the rear wall 4.

Through holes 8 (Fig.2) in the internal Central partition 7 in the array 3 and rear wall 4 welded camera 2, the distance between the edges of the oval through-holes 8 are within l1/d2min=1,5-2,0, where l2- the distance between the edges of the pass-through oval openings 8 between them, d2min- minor axis of the oval bore hole 8.

The distance between the edges of the oval through-holes 8 and welds connecting the internal Central partition 7 with the tube plate 3 and rear wall 4 welded camera 2, is chosen in the range l3Sn=1,5-2,0, where l3- the distance between the edges of the oval through-holes 8 and the walls welded camera, Sn- the thickness of a partition.

The analysis of the properties of the design of the air cooler with the use of the material to reflect changes in structural embodiment which provides the optimal location of the holes in the tube sheet holes under the beams of the tubes and oval through-holes in the internal Central partition relative to each other and relative to the location of welds, shows the following.

The positive effect from the use of the present invention is confirmed by calculation of the ratio of the intensity of the voltage - k1for the Def which can be located near the edges of holes and places of tee and corner welds.

The stress intensity factor k1does not exceed 15 MPM1/2that in 2 times below the threshold value k1thaccording to the NACE standard TM 0177-96 [5].

In addition, preliminary analysis also shows that the reduction in terms of crack nucleation increases the reliability, and therefore, the lifetime of the sections of the air cooling units, including improved operational characteristics of the manufactured devices providing opportunities ultrasonic inspection of all elements of the design in meeting the cost of manufacture.

In this range of requirements for the materials for this invention, based on the international standard NACE [5], includes a wide range of structural materials, in particular steel 20KA, UC, which has the following characteristics according to the content of impurities:

Sulfur is Not more than 0.005%

Phosphorus Not more than 0,020%

nonmetallic inclusions:

Sulfides “With” Not more than 2.0 points

Oxides strachocina “OS” Not more than 2.5 points

Silicates fragile “CX” Not more than 2.5 points

Thus, for the invention in the form as it is described in the independent clause following claims, confirmed the possibility is sledovatelno, claimed claimed invention meets the requirement of “industrial applicability” under the current law.

Sources of information

1. A. C. the USSR # 172414, CL 23 P 15/26, 1965.

2. RF patent №2176583, CL 23 P 15/26, 2001.

3. The branch standard OST 26-02-1309-87. Air cooling units. General technical conditions.

4. OST 26-2044-83 "Seams butt and corner welds of vessels and equipment working under pressure. The method of ultrasonic testing".

5. Standard Test Method. Laboratory Testing of Metals for Resistance to Sulfide Stress Cracking and Stress Corrosion Cracking in H2's Environments. NACE International, 1996.

Claims

1. A method of manufacturing sections of the air cooling unit, in which two beam pipes is sealed by expanding connected to tube sheet weld chamber having a back wall with holes for tubes made of coaxial holes of the grid, set the internal Central partition between the two beam pipes, which have symmetrically with respect to the internal Central partition, in the last perform pre-holes for passage of the working fluid with reduced total cross-section is not less than the total flow section any cracking when working in corrosive environments, for example, fluids containing hydrogen sulfide environment, the materials of the structural elements used a carbon steel, the characteristics of which are selected from the following conditions impurity content:

Sulfur is Not more than 0,0065%

Phosphorus does Not exceed 0.025%

and non-metallic inclusions:

Sulphides “With” Not more than 2.0 points

Oxides strochechnyh “OS” Not more than 2.5 points

Silicates fragile “CX” Not more than 2.5 points

2. The method according to p. 1, characterized in that the sheet metal for the manufacture of tube and the rear wall with the holes of the tube is chosen from the condition that the size of the area of each region of the accumulation of non-metallic inclusions did not exceed 20% of the size of the area running holes, and the size of the total area of clusters of non-metallic inclusions did not exceed 0.5% of the total area of the holes.

3. The method according to any of paragraphs.1 and 2, characterized in that the distance between the groups of the tube bundle is chosen from the condition

l11,5 d1,

where l1- the distance between the axes of the outermost holes of the lattice included in the corresponding group;

d1- the diameter of the holes in the lattice under the beam pipe and tubes in the rear.

4. The method according to any of paragraphs.1-3, is great for the receiving of the major axis d2maxperpendicular to the plane of arrangement of the grating and the rear wall welded camera, and the ratio of the distance between the edges of the oval through-holes to the minor axis of the holes are within

l2/d2min=1,5-2,0,

where l2- the distance between the edges of the oval through-holes;

d2min- minor axis of the oval hole,

and the distance between the edges of the oval through-hole and grille or rear wall welded camera choose within

l3Sn;

where l3- the distance between the edges of the oval holes and walls welded camera

Sn- the thickness of a partition, Sn=1,5-2,0.



 

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