RU2265775C1 - Regenerative air heater - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: regenerative power heater comprises at least two sections which receive at least two heat exchanging units and diffuser and contraction pipe for supplying and discharging fluid to be cooled, and collectors for supplying and discharging the fluid to be heated. The heat exchangers are composed of four branches of heat exchanging pipes. The collectors are connected with the heat exchange pipes through individual pipe plates embedded directly into the wall of the corresponding collector for supplying and discharging air. Each of the heat exchanging pipes is provided with four or five or six bends.

EFFECT: enhanced efficiency.

21 cl, 2 ex, 2 tbl

Description

The invention relates to a power system, and in particular, to devices for recovering heat from exhaust gases from aggregates, in particular for heating air with exhaust products from a compressor of a gas turbine installation of a gas pumping unit at compressor stations of gas mains.

Known air heater (SU, No. 992920, F 12 L 15/04, 1983) containing blocks located one above the other and mounted on the lower frame of the heat exchange sections, formed by vertical tubes with horizontal tube boards, rigidly fastened to each other and the upper distribution box equipped with a compensator for temperature changes, while the air heater is equipped with a power belt with spring supports covering the junction box, rigidly fastened to the belt in the area below its compensator, and in Chez last interaction with its spring supports.

Also known is a regenerative air heater (SU, No. 985595, F 12 L 15/04, 1982) containing a tube plate with a bundle of heat exchange tubes fixed therein, arranged in vertical rows, the planes of which are perpendicular to the supporting edges of the tube plate, while reducing thermal stresses of the pipe in the places of fixing the tube bundle in the pipe pipe boards in rows in sections located on the side of the supporting edges of the pipe board are connected with each other and with the pipe boards by additional spacers.

The disadvantages of the above devices include their high metal consumption due to the presence of vertical heat transfer tubes and horizontal tube boards. In the first analogue, the load from the upper distribution box is perceived through the blocks of the heat exchange sections by the lower frame, and therefore the introduction of a power belt with spring supports was required. In the second analogue, in order to reduce thermal stresses, it was necessary to introduce spacers connecting the pipes together and with the tube plate.

The closest analogue is a regenerative air heater (RU, No. 31838 F 23 L 15/04, 2002), containing heat-exchange units having bundles of heat-exchange tubes bundled into ends, the ends of which are fastened to collectors for supplying and discharging air, the heat-exchange tube bundle has the shape of the coil is made in a single package, while the fastening elements of the heat exchange pipes to the collectors are made in the form of separate tube plates welded directly into the wall of the corresponding collector.

The disadvantages of the closest analogue include the fact that it does not provide high thermal efficiency, as well as the compactness of the stacking of heat transfer pipes, while ensuring strength and rigidity of the structure, as a result of which the closest analogue has an increased metal consumption.

The problem solved by the invention is to increase the heat transfer efficiency while increasing the strength and rigidity of the structure and reducing metal consumption.

The problem is solved due to the fact that the regenerative block-sectional air heater according to the invention contains at least two sections, each of which contains at least two heat-exchange units, each of which includes a four-way multi-row bundle of heat-exchange pipes consisting of four branches laid in horizontal rows and spaced horizontally and vertically from each other, and also includes a diffuser for supply and a confuser for removal of the cooled medium, supply manifolds and of the outlet of the heated medium, each of which is connected to the heat exchange tubes by means of separate tube plates mounted directly into the wall of the corresponding collector of the inlet or outlet of the heated medium, each heat exchange tube of a row is made with four, five or six bends of radius R, forming four straight branches and connecting them three bends, while the bending sections of two pipes in each odd row have a length πR, namely, one pipe has an inner bend, the other has two external bends, for the rest of odd and even rows of pipes, the bend sections are πR / 2 long and are paired by means of straight inserts of length H ' _i , for the outer elbows and H'' _i - for the inner elbow, while placing the pipes in the volume occupied by at least one branch beam, taken in compliance with the conditions, according to the first of which the ratio of the total area ∑F _ntp the outer surface of the heat exchange tubes of the bundle branches to the volume ΣF _MS occupied by the annular medium in the area of active heat transfer of the beam branch and equal to the volume of the beam branch along the external contour defined by the conditional planes touching the outer surfaces of the extreme heat transfer tubes of the beam branch, minus the volume occupied by the heat transfer tubes in this beam branch, is in the range of values determined by the coefficient

components (84.5-460) [m ^-1 ], according to the second condition, the ratio of the total volume ∑V _century.c. for the heated medium in the pipes of the beam branch to the volume V _m.s. determined by the coefficient

constituting 0.78-1.25.

In this case, the parameters of each row pipe can be determined by the dependencies:

L _{i + 1} = 2l ' _{i + 1} + 2l'' _{i + 1} -Δ + 2H' _{i + 1} + H '' _{i + 1} + 3πR,

where L _{i + 1} is the scan length of the (i + 1) th row pipe, [m];

l ' _{i + 1} is the length of the external straight branch (i + 1) of the row pipe equal to l' _{i + 1} = l ' _i -b, [m];

l " _{i + 1} is the length of the internal straight branch (i + 1) of the row pipe equal to l" _{i + 1} = l ' _i -Δ, [m];

H ' _{i + 1} - the length of the rectilinear inserts of the outer elbows of the (i + 1) th pipe of the row, equal to H' _{i + 1} = H ' _i -2a, [m];

H " _{i + 1} - the length of the straight insert of the inner bend of the (i + 1) th pipe of the row, equal to H" _{i + 1} = H " _i + 2a, [m];

a - step between the longitudinal axes of the same straight branches of the same adjacent in a row of pipes, [m];

b is the step between the longitudinal axes of the rectilinear inserts of the elbows of adjacent pipes in a row, [m];

Δ is an empirical value equal to [3-12] · 10 ^-3 , [m];

l ' _i , l'' _i , H' _i and Н '' _i are the corresponding parameters for the i-th pipe in the row, counting from the outer pipe to the inner one in this row, and step a is (1.5-2.5 ) · D, step b is (1.8-2.8) · d, where d is the outer diameter of the heat exchanger pipe, [m], the scan length L _{min of the} heat transfer pipe of the minimum length is at least 0.75 of the scan length L _{max of the} heat transfer pipes of maximum length, while the placement of heat transfer pipes in a row can be selected subject to the condition according to which the ratio of the internal surface area of heat transfer pipes to straight the branches of the row, perpendicular to the flow of the cooled medium, to the volume occupied by the series of heat transfer tubes and equal to the volume outlined by the conditional planes touching the outer surfaces of the heat transfer tubes of the row, taking into account the gaps between the pipes, is 0.02-0.12 [m ^-1 ].

In each section of the regenerative air heater, the heat exchange units can be located one above the other, and the preferred number of units is four.

The collectors for supplying and discharging the heated medium can be made with the possibility of connecting with pipelines for supplying and discharging the heated medium, which is preferably used air, including with an enriched oxygen content, while the products of combustion after the turbine of a gas turbine can be used as a cooled medium , mainly of the following composition:

CO ₂ 1.0-1.5% O ₂ 18-20% With 0.01-0.02% CH ₄ and H ₂ traces N ₂ rest

when the content of nitrogen oxides is not more than 220 mg / m ³ and the coefficient of excess air is 5-8.

In each row, the step a between the longitudinal axes of adjacent pipes of rectilinear branches may be smaller or larger than the step b between the longitudinal axes of adjacent pipes in the section of straight knee inserts, preferably a <b, or step a is equal to step b.

The number of heat transfer tubes in the adjacent rows of the beam for odd and even rows can be respectively m and n, where m is an even number and n = (m-1), the number of rows of tubes in the bundle k is preferably odd, and k> 3 , heat-exchange pipes in rows adjacent in height are placed in a checkerboard pattern with an offset of (0.4 ÷ 0.6) a , [m], where a is the step between the longitudinal axes of the rectilinear branches of adjacent pipes of the same row, [m], while length H _'i and H'_'i rectilinear inserts knee i-th tube formed variables: for an odd number of heat exchange tubes changing from a value equal to 2a ± 10%, [m], to a value equal to 2a (m-1) ± 10%, [m], and for an even row, from a value equal to a ± 10%, [m], to a value equal to a (2n-1) ± 10%, [m].

The number N of heat exchange tubes in the block with an odd number of rows of k tubes in the bundle can be determined by the dependence N = 0.5 (k-1) (2m-1) + m and is preferably 263-563 pcs.

The number N of heat exchange tubes in the block with an even number of rows of k tubes in the bundle can also be determined by the dependence N = 0.5k (2m-1) and is preferably 263-563 pcs.

For each beam heat exchange tube, the distance H between the longitudinal axes of its external straight branches is (30-85) d; the length of the straight branches l 'and l' 'is (95-145) d and (100-135) d, respectively, where d is the outer diameter of the heat exchanger pipe, [m].

Between the inlet and outlet collectors of the heated medium, an annulus displacer can be fixed, made in the form of a profiled panel with a flat section located between the inlet and outlet collectors of the heated medium.

The cross-sectional area of the inlet or outlet of the heated medium collectors can be 0.45-0.82 of the total cross-sectional area of the beam heat-transfer tubes.

The heat exchange unit can be equipped with slinging devices and manholes made in collectors for supplying and discharging a heated medium.

The total length l ' _∑ and l'' _{∑ of the} straight sections of the pipes of the external and internal branches of the heat exchange tube bundle, perpendicular to the flow of the cooled medium, can be at least 72% of the total length of the sweeps L _{∑ of the} heat transfer tubes, and the total length of the straight inserts H' _∑ and H ' _{∑ of the} elbows of the heat exchange tubes of the beam, the heated medium in which is located in countercurrent with the cooled medium, amounts to 18% of the total length of the sweeps L _{∑ of the} heat exchange tubes of the beam.

A regenerative air heater, equipped with a diffuser for supply and a confuser for the removal of the cooled medium, can be installed respectively on the opposite side walls of the section.

The technical result provided by the above set of essential features is to ensure high heat transfer efficiency while reducing the metal consumption of the regenerative air heater.

It is known that the efficiency of heat exchangers mainly from transversely streamlined pipes to a large extent depends on the parameters of the heat exchange surface, which is characterized, in particular, by the area of the total heat exchange surface washed by the cooled medium (combustion products), the area of the passage section for the heated medium (air), and others characteristics, the optimal selection of which allows to increase the efficiency of heat transfer, to reduce the mass and size of heat exchangers.

The invention allows to optimize the nature of the flow of high-temperature combustion products of a four-way multi-row bundle of heat-exchange tubes filled with heated air. This is ensured by the design of the heat exchange unit of the air heater section using experimentally obtained coefficients that take into account, with known properties of the coolant, the surface geometric parameters.

High heat exchange efficiency of the regenerative air heater is achieved due to the proposed volumetric placement of heat exchange pipes (compliance with a certain packing density), which ensures good washability of their surface with combustion products (cooled medium), as well as the shape of the heat transfer pipes. The volumetric placement of heat transfer tubes in the beam branch of the heat exchange unit was carried out using the coefficients ν and μ, in accordance with which it is possible, for example, for given initial parameters (flow rate of heated air, dimensions of the heat exchange unit, etc.) to determine the optimal geometric characteristics of the heat exchange beam pipes in the zone of active heat transfer, providing high heat transfer efficiency. The proposed ranges of the values of the coefficients ν and μ allow, along with high heat transfer efficiency, to achieve the minimum metal consumption if, in this case, the heat transfer tubes are made of single-pack four-way ones.

The implementation of the regenerative air heater in a block-sectional manner and the arrangement of the heat exchange units in the section one above the other can reduce the loss of heat energy, reduce the metal consumption of the means providing the supply and removal of combustion products. The use of a displacer with a flat surface facing the inside of the heat exchange unit, to which there are adjacent straight sections of elbows with a length of H '', together with the features of any of the preceding claims, ensures the absence of stagnant zones of the cooled medium (combustion products) near the collectors and optimal heat transfer in the straight sections pipes, the heated medium in which is located in countercurrent with the cooled medium.

The invention is illustrated by drawings, which depict:

figure 1 - regenerative air heater, side view;

figure 2 is the same, a top view;

figure 3 - heat transfer unit regenerative air heater, top view;

figure 4 - heat transfer pipe, top view;

figure 5 - node a in figure 3;

figure 6 is a section bB in figure 3;

Fig.7 is a heat exchange unit of a regenerative air heater with open manhole covers, a top view;

on Fig - block regenerative air heater in a perspective view.

The regenerative air heater 1 block-sectional contains at least two sections 2, inside each of which at least two heat-exchange blocks 3 are placed, each of which includes a four-way multi-row bundle 6 of heat exchange tubes 6, laid horizontally, consisting of four branches 4, 5 in rows 8 and spaced horizontally and vertically from each other, and also includes a diffuser 9 for supply and a confuser 10 for removal of the cooled medium, collectors 11 for supply and removal of the heated medium, each of which is connected to heat exchange tubes 7 through separate tube plates 12 mounted directly into the wall of the corresponding collector 11 for supplying and discharging the heated medium, each heat exchange tube 7 of the row is made with four, five or six bends 13, 14 of radius R, forming four straight branches 4, 5 and connecting there are three bends 15, 16, while the bending sections 13 of two pipes 7 in each odd row 8 have a length πR, namely, one pipe 7 has an internal bend 15, the other 7 has two external bends 16, for the remaining pipes 7 odd and even p rows 8 portions bend 14 have a length πR / 2 and articulated in pairs by straight inserts 17 length H _'i for the external legs 16 and H'_'i - for the inner elbows 15, wherein the placing tubes 7 in the volume occupied by at least one branch 4 or 5 beams, taken in compliance with the conditions, according to the first of which the ratio of the total area ∑F _ntp the outer surface of the heat exchange pipes 7 that branch 4 or 5 of the beam 6 to the scope ΣV _MS occupied by the annular medium in the area of active heat transfer of the branch 4 or 5 of the beam 6 and equal to the volume of the branch 4 or 5 of the beam 6 along the external contour outlined by the conditional planes touching the outer surfaces of the extreme heat exchange tubes 7 of the branch 4 or 5 of the beam 6, minus the volume occupied the actual heat exchange tubes 7 in this branch 4 or 5 of the beam 6, is in the range of values determined by the coefficient

components (84,5-460) [m ^-1], the second condition the ratio of the total volume _VS ΣV for a heated medium in pipes 7 of branch 4 or 5 of beam 6 to a volume of V _m.s. determined by the coefficient

constituting 0.78-1.25.

The parameters of each pipe 7 of row 8 are determined by the dependencies:

L _{i + 1} = 2l ' _{i + 1} + 2l'' _{i + 1} -Δ + 2H' _{i + 1} + H '' _{i + 1} + 3πR,

where L _{i + 1} is the scan length of the (i + 1) th pipe 7 of row 8, [m];

l ' _{i + 1} - the length of the outer straight branch of the 5 (i + 1) th pipe 7 of row 8, equal to l' _{i + 1} = l ' _i -b, [m];

l " _{i + 1} is the length of the inner straight branch of the 4 (i + 1) th pipe 7 of row 8, equal to l" _{i + 1} = l ' _i -Δ, [m];

H ' _{i + 1} - the length of the rectilinear inserts 17 of the outer elbows of the 16 (i + 1) th pipe 7 of row 8, equal to H' _{i + 1} = H ' _i -2a, [m];

H '' _{i + 1} - the length of the straight insert 17 of the inner bend of the 15 (i + 1) th pipe 7 of row 8, equal to H '' _{i + 1} = H '' _i + 2a, [m],

a - step between the longitudinal axes of the same straight branches 4 or 5 adjacent in a row of 8 pipes 7, [m];

b is the step between the longitudinal axes of the rectilinear inserts 17 of the elbows 15, 16 adjacent pipes 7 in a row 8, [m];

Δ is an empirical value equal to [3-12] · 10 ^-3 , [m];

l ' _i , l'' _i , H' _i and H '' _i are the corresponding parameters for the i-th pipe 7 in row 8, counting from the outer pipe 18 to the inner 19 in this row 8, and step a is (1, 5-2.5) · d, step b is (1.8-2.8) · d, where d is the outer diameter of the heat transfer pipe 7, [m], the scan length L _{min of the} heat transfer pipe 7 of the minimum length is at least 0 75 scanning length L _max of the heat exchange tube 7 the maximum length, the placement of heat exchange tubes 7, 8 in the row selected in compliance with conditions under which the internal surface area ratio of the heat exchange tubes 7 rectilinearly x branches 4, 5 of row 8, located perpendicular to the flow of the cooled medium, to the volume occupied by a number of 8 heat exchange tubes 7, and equal to the volume outlined by the conditional planes touching the outer surfaces of the heat exchange tubes 7 of row 8, taking into account the gaps between the tubes 7, is 0 , 02-0.12 [m ^-1 ].

In each section 2 of the regenerative air heater 1, the heat exchange units 3 are located one above the other, and the preferred number of units 3 is four.

The collectors 11 for supplying and discharging the heated medium are made with the possibility of connecting with pipelines for supplying 20 and discharging 21 of the heated medium, which is preferably used air, including with an enriched oxygen content, while the products of combustion after the turbine of a gas turbine are used as a cooled medium ( not shown in the drawings), mainly of the following composition:

CO ₂ 1.0-1.5% O ₂ 18-20% With 0.01-0.02% CH ₄ and H ₂ traces N ₂ rest

when the content of nitrogen oxides is not more than 220 mg / m ³ and the coefficient of excess air is 5-8.

In each row 8, step a between the longitudinal axes of adjacent pipes 7 of straight branches 4, 5 is less than or greater than step b between the longitudinal axes of adjacent pipes 7 on straight insert 17 of elbow 15, 16, preferably a <b or step a is equal to step b.

The number of heat exchange tubes 7 in rows 8 adjacent to the height of the beam 6 for odd and even rows 8 is respectively m and n, where m is an even number and n = (m-1), the number of rows 8 of pipes 7 in the bundle 6 k is preferably the odd, and k> 3, heat transfer tubes 7 in rows adjacent in height 8 are staggered with an offset of (0.4 ÷ 0.6) a, [m], where a is the step between the longitudinal axes of the straight branches 4, 5 adjacent tubes 8 of one row 7, [m], and the length H _'i and H'_'i rectilinear knee inserts 17, 16 and 15, respectively, i-th tube 7 are made variables: for odd pn and 8 heat exchange tubes 7 varying from a value equal to 2a ± 10%, [m], to a value equal to 2a (m-1) ± 10%, [m], and for an even row of 8, from a value equal to a ± 10 %, [m], to a value equal to a (2n-1) ± 10%, [m].

The number N of heat exchange tubes 7 in block 3 with an odd number of rows of k tubes 7 in bundle 6 is determined by the dependence N = 0.5 (k-1) (2m-1) + m and is preferably 263-563 pcs.

The number N of heat exchange tubes 7 in block 3 with an even number of rows k of tubes 7 in bundle 6 is determined by the dependence N = 0.5k (2m-1) and is preferably 263-563 pcs.

For each heat exchange tube 7 of the bundle 6, the distance H between the longitudinal axes of its outer straight branches 5 is (30-85) d; the length of the straight branches l 'and l' 'is (95-145) d and (100-135) d, respectively, where d is the outer diameter of the heat exchange tube 7, [m].

Between the collectors 11 of the inlet and outlet of the heated medium, a displacer 22 of the annular medium is fixed, made in the form of a profiled panel with a flat section located between the collectors 11 of the inlet and outlet of the heated medium.

The cross-sectional area of the collectors 11 for supplying and discharging the heated medium is 0.45-0.82 of the total cross-sectional area of the heat-transfer tubes 7 of the beam 6.

The heat exchange unit 3 is equipped with devices 23 for slinging and manholes (not shown), made in the collectors 11 for supplying and discharging the heated medium.

The total length l ' _∑ and l'' _{∑ of the} straight sections of the pipes 7 of the outer 5 and inner 4 branches of the bundle 6 of the heat transfer tubes 7, perpendicular to the flow of the cooled medium, is at least 72% of the total length of the sweeps L _{∑ of the} heat transfer tubes 7, and the total length of the straight inserts H ' _∑ and H'' _{∑ of the} bends 16 and 15, respectively, of the heat exchange tubes 7 of the beam 6, the heated medium in which is located in countercurrent with the cooled medium, makes up to 18% of the total length of the reamers L _{∑ of the} heat exchange tubes 7 of the beam 6.

The regenerative air heater 1 is equipped with a diffuser 9 for supply and a confuser 10 for draining the cooled medium, respectively mounted on the opposite side walls of section 2.

The operation of the regenerative air heater 1 is as follows.

The air intended for the combustion of a gas turbine plant enters a compressor, in which it is compressed, and then through a supply pipe 20 through a manifold for supplying a heated medium and a pipe board 12 to the heat exchange pipes 7 of blocks 3 of each section 2. The air temperature after the compressor is about 200 ° C.

The combustion products of the above composition from the turbine turbine unit through a diffuser 9 adjacent to the bodies of the heat exchange units 3, enter the block 3 of section 2 and wash the heat exchange pipes 7 with heated air. The combustion products are supplied to the heat exchange units 3 in countercurrent with the direction of movement of the heated air, that is, the combustion products enter the heat exchange unit 3 from the location of the collector of the outlet of the heated medium. At the entrance to the heat exchange unit 3, the combustion products have a temperature of 520-550 ° C.

Passing through the heat exchange pipes 7 of blocks 3, the air is heated by the combustion products to a temperature of 440-450 ° C and through the pipe board 12 it enters the collector of the outlet of the heated medium, from which it is fed through the pipeline 21 to the inlet of the gas turbine combustion chamber.

The combustion products are discharged into the atmosphere through a confuser 10 adjacent to the housings of the heat exchange units 3.

The high heat exchange efficiency of the regenerative air heater made according to the invention is determined by the geometric characteristics of the unit and heat exchange tubes, selected using experimental coefficients that take into account the geometric parameters of the surface with the known properties of the heated medium — air and the cooled medium — GTU combustion products. Moreover, the invention provides a reduction in the mass and dimensions of the heat exchange units.

Example 1

To construct an odd row of a bundle of heat exchange tubes of a regenerative air heater unit according to this invention.

Given: The pipe row is composed of four-branch bent pipes with a diameter of ⌀25 × 1.0 mm. Each pipe contains two external rectilinear branches of length l ', two internal rectilinear branches each of length l'', two external bends, each formed by two bends of radius R at an angle π / 2 and a length πR / 2 and a straight insert with a length H', and one inner bend formed by two bends of radius R at an angle π / 2 and a length πR / 2 with a straight insert H ''. Pipes in a row are arranged with a step a between the axes of the branches of the same name and a step b between the axes of the straight inserts of the same elbows.

The design of the pipe series is carried out from the condition of the most dense pipe packing in the block.

The dimensions of the internal volume of the block in the plan for placing the rows of heat-exchange tubes forming a bundle are 3130 × 1650 mm. Based on this, we set the dimensions of the pipe elements No. 1 l ' ₁ = 3060 mm, l'' ₁ = 2639.5 mm, H' ₁ = 480 mm, H '' ₁ = 0 mm. The pitch between the axes of the pipe branches of the same name in the row a = 48 mm; step between the axes of the knees b = 48 mm; bending radius R = 100 mm.

The parameters of the remaining pipes of the series are determined by the dependencies given in the invention.

The results are shown in Table 1.

Table 1 i N ' _i , mm N '' _i , mm l ' _i , mm l '' _i , mm L _i mm 1 480 0 3060 2639.5 13301.5 2 384 96 3012 2645.5 13121.5 3 288 192 2964 2651.5 12941.5 4 192 288 2916 2657.5 12761.5 5 96 384 2868 2663.5 12581.5 6 0 480 2820 2669.5 12401.5

Example 2

To construct an even row of the heat exchange tube bundle of the regenerative air heater unit of the present invention.

Given: The pipe row is composed of four-branch bent pipes with a diameter of ⌀25 × 1.0 mm. Each pipe contains two external rectilinear branches of length l ', two internal rectilinear branches each of length l'', two external bends, each formed by two bends of radius R at an angle π / 2 and a length πR / 2 and a straight insert with a length H', and one inner bend formed by two bends of radius R at an angle π / 2 and a length πR / 2 with a straight insert H ''. Pipes in a row are arranged with a step a between the axes of the branches of the same name and a step b between the axes of the straight inserts of the same elbows.

The design of the pipe series is carried out from the condition of the most dense pipe packing in the block.

The dimensions of the internal volume of the block in the plan for placing the rows of heat-exchange tubes forming a bundle are 3130 × 1650 mm. Based on this, we set the dimensions of the pipe elements No. 1 l ' ₁ = 3036 m, l'' ₁ = 2642.5 m, Н' _i = 432, Н '' ₁ = 48 m. The step between the axes of the pipe branches of the same name in a row = 48 mm; step between the axes of the knees b = 48 mm; bending radius R = 100 mm.

The parameters of the remaining pipes of the series are determined by the dependencies given in the invention.

The results are shown in Table 2.

table 2 i H ' _i , mm H '' _i , mm l ' _i , mm l '' _i , mm L _i mm 1 432 48 3036 2642.5 13211.5 2 336 144 2988 2648.5 13031.5 3 240 240 2940 2654.5 12851.5 4 144 336 2892 2660.5 12671.5 5 48 432 2844 2666.5 12491.5

Claims (14)

1. Regenerative block-sectional air heater, characterized in that it contains at least two sections, each of which contains at least two heat exchange units, each of which includes a four-way multi-row bundle of heat exchange pipes consisting of four branches, laid horizontally and spaced horizontally and vertically from each other, and also includes a diffuser for supply and a confuser for removal of the cooled medium, collectors for supply and removal of the heated medium, each which are connected to heat exchange tubes by means of separate tube plates mounted directly into the wall of the corresponding air supply or exhaust manifold, each heat exchange tube of a row is made with four, or five, or six bends of radius R, forming four straight branches and connecting three knees, while bending sections of two pipes in each odd row have a length πR, namely, one pipe has an inner bend, the other has two external bends, and for the remaining pipes of odd and even rows iba have a length πR / 2 and articulated in pairs by straight inserts length N _'i for external knee and H'_'i - for the inner elbows, the placement of pipes in the volume occupied, at least one branch of the beam, taken under the conditions , according to the first of which the ratio of the total area ∑F _{bhp of the} external heat exchange surface of the pipes of this beam branch to the volume of ∑V _ms occupied by the annular medium in the area of active heat transfer of the beam branch and equal to the volume of the beam branch along the external contour outlined by conventional planes asayuschimisya extreme outer surfaces of the heat exchange tube bundle branches, minus the volume occupied by the actual heat exchange tubes in the bundle branches, is in the range of values defined by the ratio

constituting 84.5-460 m ^-1 , according to the second condition, the ratio of the total volume вV _century for the heated medium in the pipes of the beam branch to the volume V _ms is determined by the coefficient

constituting 0.78-1.25. 2. The regenerative air heater according to claim 1, characterized in that the parameters of each row pipe are determined by the dependencies L _{i + 1} = 2l ' _{i + 1} + 2l'' _{i + 1} -Δ + 2H' _{i + 1} + H '' _{i + 1} + 3πR, where L _{i + 1} is the scan length of the (i + 1) th row pipe, m; l ' _{i + 1} is the length of the outer straight branch (i + 1) of the row pipe equal to l' _{i + 1} = l ' _i -b, m; l '' _{i + 1} is the length of the internal rectilinear branch of the (i + 1) th pipe of the row, equal to l '' _{i = 1} = l ' _i -Δ, m; H ' _{i + 1} - the length of the rectilinear inserts of the outer elbows of the (i + 1) th pipe of the row, equal to H' _{i + 1} = H ' _i -2a, m; H '' _{i + 1} is the length of the straight insert of the inner bend of the (i + 1) th pipe of the row, equal to Н '' _{i + 1} = Н '' _i + 2a, m; a is the step between the longitudinal axes of the same rectilinear branches adjacent in a row of pipes, m; b is the step between the longitudinal axes of the rectilinear inserts of the elbows of adjacent pipes in a row, m; Δ is an empirical value equal to (3-12) · 10 ^-3 m; l ' _i , l'' _i , Н' _i and Н '' _i are the corresponding parameters for the i pipe in the row, counting from the outer pipe to the inner one in this row, and step a is (1.5-2.5) · d, step b is (1.8-2.8) · d, where d is the outer diameter of the heat exchanger pipe, m, the scan length L _{min of the} heat exchanger pipe of the minimum length is not less than 0.75 scan length L _{max of the} heat exchanger pipe of the maximum length, while the placement of the heat exchanger tubes in a row is selected subject to the condition according to which the ratio of the internal surface area of the heat exchanger tubes on the straight branches of the row perpendicular to the flow of the cooled medium to the volume occupied heat exchange tubes, and mu volume delineated conventional planes tangent to the outer surfaces of a number of heat exchange tubes, with the gaps between the tubes is 0,02-0,12 m ^-1. 3. The regenerative air heater according to claim 1, characterized in that in each of its sections the heat exchange units are located one above the other, and the preferred number of blocks is four. 4. The regenerative air heater according to claim 1, characterized in that the manifolds for supplying and discharging the heated medium are adapted to be connected to pipelines for supplying and discharging the heated medium, preferably air being used, including with an enriched oxygen content, of the cooled medium, combustion products are used after the turbine of a gas turbine installation, mainly of the following composition: CO ₂ 1.0-1.5% O ₂ 18-20% With 0.01-0.02% CH ₄ and H ₂ traces N ₂ rest when the content of nitrogen oxides is not more than 220 mg / m ³ and the coefficient of excess air is 5-8. 5. The regenerative air heater according to claim 1, characterized in that in each row the step a between the longitudinal axes of the adjacent pipes of the rectilinear branches is less than or greater than the step b between the longitudinal axes of the adjacent pipes in the section of the straight knee insert, preferably a> b, or the step and is equal to step b. 6. The regenerative air heater according to claim 2, characterized in that the number of heat exchange tubes in the adjacent rows of the beam for odd and even rows is respectively m and n, where m is an even number, and n = (m-1), the number of rows tubes in the bundle k is preferably odd, and k> 3, the heat transfer tubes in rows adjacent in height are staggered with an offset of (0.4 ÷ 0.6) a, m, where a is the step between the longitudinal axes of the rectilinear branches of adjacent pipes of one row m, the length H _'i and H'_'i rectilinear inserts knee i-th tube made ne temporary: for an odd row of heat transfer tubes varying from a value equal to 2a ± 10%, m, to a value equal to 2a (m-1) ± 10%, m, and for an even row - from a value equal to a ± 10%, m , to a value equal to a (2n-1) ± 10%, m. 7. The regenerative air heater according to claim 6, characterized in that the number N of heat exchange tubes in the block with an odd number of rows of k tubes in the bundle is determined by the dependence N = 0.5 (k-1) (2m-1) + m and is preferably 263 -563 pcs. 8. The regenerative air heater according to claim 6, characterized in that the number N of heat exchange tubes in the block with an even number of rows k of tubes in the bundle is determined by the dependence N = 0.5k (2m-1) and is preferably 263-563 pcs. 9. The regenerative air heater according to claim 2, characterized in that for each beam heat exchanger pipe, the distance H between the longitudinal axes of its external straight branches is (30-85) d; the length of the rectilinear branches l 'and l' 'is respectively (95-145) d and (100-135) d, where d is the outer diameter of the heat exchange pipe, m 10. The regenerative air heater according to claim 1, characterized in that between the manifolds of the inlet and outlet of the heated medium is fixed a displacer of the annular medium, made in the form of a profiled panel with a flat section located between the manifolds of the inlet and outlet of air. 11. The regenerative air heater according to claim 1, characterized in that the passage area of the collector for supplying or discharging the heated medium is 0.45-0.82 of the total passage area of the beam heat exchange tubes. 12. The regenerative air heater according to claim 1, characterized in that the heat exchange unit is equipped with slinging devices and manholes made in the headers for supplying and discharging the heated medium. 13. The regenerative air heater according to claim 1, characterized in that the total length l ' _∑ and l'' _{∑ of the} straight sections of the pipes of the external and internal branches of the bundle of heat transfer pipes perpendicular to the flow of the cooled medium is at least 72% of the total length of the sweeps L _∑ heat transfer tubes, and the total length of the straight inserts H ' _∑ and H'' _{∑ of the} elbows of the heat transfer tubes of the beam, the heated medium in which is located in countercurrent with the cooled medium, is up to 18% of the total length of the sweeps L _{∑ of the} heat transfer tubes of the beam. 14. The regenerative air heater according to claim 1, characterized in that the diffuser for supply and the confuser for the removal of the cooled medium are installed respectively on opposite side walls of the section.

Images