Tube bundle heat exchanger

Abstract

A tube bundle heat exchanger has tubes which are held at each side in tube plates or oval-tube collecting-tube plates and are connected to these in each case by means of a weld seam. The connection of the tubes to the inlet-side tube plate or oval-tube collecting-tube plate is formed in each case by means of a conical and/or trumpet-shaped transition piece. The cross section of the transition piece reduces as viewed in the gas flow direction in such a way that the inlet-side end, as viewed in the gas flow direction, of the transition piece is connected in a butt joint to the tube plate or oval-tube collecting-tube plate. The inner and outer contours of the transition piece and of the welded connection region are formed without gaps and corners to the tube plate or oval tube collecting-tube plate and so as to be straight and/or with a radius, measured from the outer contour, of at least 5 mm.

Claims

1. A tube bundle heat exchanger comprising: a gas inlet chamber adapted to receive a gas into the heat exchanger; a gas outlet chamber adapted to emit the gas from the heat exchanger; an inlet-side tube plate disposed proximate to the gas inlet chamber having a plurality of openings; an outlet-side tube plate disposed proximate to the gas outlet chamber having a plurality of openings; a plurality of tubes, each of the tubes having an inlet end and an outlet end, wherein the inlet end of each tube is welded to a respective opening of the inlet-side tube plate and the outlet end of each tube is welded to a respective opening of the outlet-side tube plate to provide fluid communication of the gas between the gas inlet chamber and the gas outlet chamber, a transition piece extending from each tube and terminating at the tube inlet end of each tube, the transition piece having an aerodynamic inner contour expanding outwardly to the respective opening of the inlet-side tube plate to provide a generally trumpet-shaped inner contour that transitions into the respective opening of the inlet-side tube plate at the inlet end, and the transition piece having an aerodynamic outer contour expanding outwardly to the respective opening of the inlet-side tube plate to provide the generally trumpet-shaped outer contour that transitions into the respective opening of the inlet-side tube plate at the inlet end; the inner contour and the outer contour of the transition piece being formed without gaps or comers to the inlet-side tube plate; and wherein a first portion of the outer contour defines an outer edge that has a first radius and a second portion of the outer contour has a second radius, the first radius being less than the second radius, wherein the first radius is at least 5 mm and the second radius is approximately 60 mm.

2. The tube bundle heat exchanger of claim 1, wherein each of the tubes has an inside diameter and a transition portion defined by an outer edge and a straight portion of the tube, the transition portion having a length that is at least 1.5 times the inside diameter of the straight portion of the tube.

3. The tube bundle heat exchanger of claim 1, wherein a straight portion of each of the tubes has a first inside diameter and an outer edge of the inlet end has a second inside diameter, the second inside diameter being at least 1.2 times the first inside diameter.

4. The tube bundle heat exchanger of claim 1, wherein the inlet end is integral with a straight portion of the tube.

5. The tube bundle heat exchanger of claim 1, further comprising an outer shell dispose around the plurality of tubes, the outer shell having a fluid inlet for receiving a heat transfer medium and a fluid outlet to exiting the heat transfer medium, wherein the heat transfer medium enters the fluid inlet, passes through the plurality of tubes to exchange heat between the medium and the gas passing through the tubes, and exits through the fluid outlet.

6. The tube bundle heat exchanger of claim 1, wherein an outer edge has a first radius and the inner contour has a second radius, the first radius being less than the second radius.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, embodiments of the invention are explained in more detail with the aid of the drawing and the description.

(2) The following are shown:

(3) FIG. 1 a longitudinal section through a tube bundle heat exchanger,

(4) FIG. 2 a detail section of the transition from the tube plate to the tube in accordance with detail A from FIG. 1,

(5) FIG. 3 as FIG. 2, but an alternative design,

(6) FIG. 4 as FIG. 2, but an alternative design,

(7) FIG. 5 a detail section of the transition of an oval tube collecting tube plate to a tube.

DETAILED DESCRIPTION

(8) FIG. 1 shows a tube bundle heat exchanger 1 represented schematically in longitudinal section. Tube bundle heat exchangers 1 of this type are needed in many material processing installations, such as, for example, gasification installations, thermal and catalytic splitting installations, steam reforming installations, etc., in which a process gas, an exhaust gas or something similar is produced. As a rule, the tube bundle heat exchanger 1 is used for cooling the hot gas 18 mentioned above, which is introduced into the gas inlet chamber 8 of the heat exchanger 1 via a line, not shown, and is directed from here through a multiplicity of straight tubes 2, subsequently collected in the gas outlet chamber 9 of the heat exchanger 1 and discharged from the heat exchanger 1 by means of a line, not shown. In that regard, the tubes 2, by means of which an indirect heat exchange with a cooling medium 19 surrounding the tubes 2 takes place, are arranged at a distance from each other between two tube plates 3, 4 or oval tube collecting tube plates 5, 6 and are connected with the latter in fixed and gas-tightusually weldedfashion.

(9) In order to keep the thermal stresses taking place at the entry of the hot gas 18 from the gas inlet chamber 8 into the particular heat exchanger tubes 2 at the inlet-side, as viewed in the gas flow direction, tube plates 3, 5 and the inlet-side ends 16 of the tubes 2 as small as possible, according to the invention the connection of the tubes 2 with the inlet-side tube plate 3 (see FIGS. 2 through 4) or oval tube collecting tube plate 5 (see FIG. 5) is formed in each case by means of a conical and/or trumpet-shaped transition piece 10 whose cross section decreases as viewed in the gas flow direction (see arrow). Moreover, the inlet-side end 16, as viewed in the gas flow direction, of the transition piece 10 is connected in the manner of a butt joint to the tube plate 3 or oval tube collecting tube plate 5, and the inner and outer contours 11, 12 of the transition piece 10 and of the welded connection region 13 are formed without gaps and corners to the tube plate 3 or oval tube collecting tube plate 5, and so as to be straight and/or with a radius, measured from the outer contour 12, of at least 5 mm.

(10) This means that the inventive design of the transition from the tube plate 3 or the oval tube collecting tube plate 5 to the tube 2 creates an aerodynamic contour 11, 12 on both the gas-contacted and cooling medium-contacted side of the tube 2, of the transition piece 10 and of the tube plate 3 or oval tube collecting tube plate 5, which does not exhibit a gap, a corner or an angular transition anywhere. This means that according to the invention, all of the transitions, including that of the welded transition region 13 to the inner or outer contour 11, 12, are either straight or flat, and/or are designed with a radius.

(11) According to FIGS. 2 and 5, the transition piece 10 is the widened, e.g. mechanically, from the tube 2 at diameter di transitioning to diameter Di at the inlet end 16 of tube 2. In this design, only weld seam 7 is needed between the tube 2 and the tube plate 3 or 5, which forms the welded connection region 13 between the tube 2 and the tube plate 3, 5. FIGS. 3 and 4 show a transition piece 10 that consists of a separate tube part 15 and is as a rule easier to manufacture, since the tube part 15 is significantly shorter than the complete tube 2 and is thus easier to process as well. For the head-side connection of the outlet-side end 17, as viewed in the gas flow direction, of the tube part 15, an additional weld seam 22 is needed, which forms the welded connection region 14 between the tube 2 and the tube part 15. This welded connection region 14 is advantageously made either straight or flat and/or with a radius both on the inside as well as on the outside contour 11, 12, i.e., the region 14 is made without corners and gaps.

(12) The transition pieces 10 according to FIGS. 2 through 5 exhibit on their inlet-side end 16, relative to the outer contour 12 of the transition pieces 10, a radius R.sub.1 of 5 mm, for example. According to FIGS. 2, 3 and 5, adjoining that is an additional radius R.sub.2 of 60 mm, for example, whereas by contrast in the case of the transition piece 10 according to FIG. 4, adjoining the first radius is a conical contraction with an adjoining radius of 20 mm, for example. The inside contour 11 of the transition pieces 10 according to FIGS. 2 and 5 then exhibits corresponding radii that are greater by the wall thickness s of the transition piece 10. If the wall thickness t of the tube plate 3, 5 does not correspond to the wall thickness s of the tube 2, then according to the invention the transition between the two wall thickness s and t within the welded connection region 13 is designed according to the invention either straight or flat and/or with a radius. A wall thickness t of the tube plates 3, 5 that differs from the wall thickness s of the tube 2 can be compensated according to FIGS. 3 and 4 with a transition piece 10 designed as a tube part 15, in that the particular wall thickness at the tube ends of the tube part 15 are adjusted to the wall thicknesses t and s of the tube plate 3, 5 as well as of the tube 2. This means that, viewed in the gas flow direction, inside the tube piece 15 the wall thickness t continuously decreases or increases to the wall thickness s. In that regard, the tube part 15 can advantageously be designed as a forged part.

(13) The length L of the transition piece 10 is advantageously 1.5 times the inside diameter di of the tube 2 and the inside diameter Di of the transition piece 10 directly at the entry into the transition piece 10 is advantageously 1.2 times the inside diameter di of the tube 2.

(14) By way of example, FIG. 4 shows in place of the trumpet-shaped transition piece 10 a conical transition piece 10, which is also formed from a separate tube part 15. Here again, the tube part 15 is connected with the tube plate 3 and the tube 2 by two weld seams 7, 22.

(15) FIG. 5 shows a tube bundle heat exchanger 1 with double tubes 2, 21 in which the cooling medium 19 circulates in the annular cross section between the inner tube 2 and the outer tube 21. Because of the outer tubes 21 that carry the cooling medium 19, the heat exchanger outer jacket 23, which is shown in FIG. 1 and which would otherwise be required, can be dispensed with. While in the case of the heat exchanger 1 shown in FIG. 1, the cooling medium 19 is fed to and discharged from the space inside the outer jacket 23 and the tube plates 3, 5 and 4, 6, according to FIG. 5 the cooling medium 19 is fed and discharged by means of oval tube collector 20. In this case, the connection of the transition piece 10 according to the invention takes place with the oval tube collecting tube plate 5.

(16) Water that is partially or completely vaporized by the addition of heat can be used as the cooling medium 19.

LIST OF REFERENCE SYMBOLS

(17) 1 Tube bundle heat exchanger 2 Tube 3 Tube plate, inlet side, 4 Tube plate, outlet side 5 Oval tube collecting tube plate, inlet side 6 Oval tube collecting tube plate, outlet side 7 Weld seam 8 Gas inlet chamber 9 Gas outlet chamber 10 Transition piece 11 Inside contour 12 Outside contour 13 Welded connection region 14 Welded connection region 15 Tube part 16 Inlet-side end of the transition piece or of the tube 17 Outlet-side end of the transition piece or of the tube 18 Gas 19 Cooling medium 20 Oval tube collector 21 Outer tube 22 Weld seam 23 Jacket