Reactor or heat exchanger with improved heat transfer performance

Abstract

Disclosed is a shell-and-tube reactor or heat exchanger comprising: first tubes, through the inside of which a first object for heat transfer with a heat transfer medium is passed, some of the first tubes being provided in a zone in which a flow of the heat transfer medium (parallel flow) parallel to the axis of the tubes is present; and a second tube, through the inside of which the first object is not passed, the second tube being provided in said zone such that it is parallel to the axis of the first tubes. Also disclosed is a method for producing an oxide, comprising using said shell-and-tube reactor or heat exchanger, and causing a catalytic vapor-phase oxidation reaction in first tubes, through the inside of which the first object for heat transfer with the heat transfer medium is passed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view schematically showing the structure of a prior general shell-and-tube catalytic reactor or heat exchanger.

FIG. 2 is a cross-sectional view schematically showing the structure of a reactor or heat exchanger according to one embodiment of the present invention, in which a non-reaction tube having a given diameter is placed in the central portion of the reactor or heat exchanger in order to improve heat transfer efficiency.

FIG. 3 is a cross-sectional view schematically showing the structure of a reactor or heat exchanger according to another embodiment of the present invention, in which a non-reaction tube, having a given diameter and a passage for the inlet or outlet of a heat transfer medium, is placed in the central portion of the reactor or heat exchanger in order to improve heat transfer efficiency.

FIG. 4 is a cross-sectional view taken along line X-X′ in FIG. 2 or 3, which illustrates the sizes of a non-reaction tube zone, a reaction tube zone and a doughnut-type baffle plate and shows the cross section of a reactor or heat exchanger according to an embodiment of the present invention, in which one non-reaction tube having a given diameter is placed in the center of the reactor or heat exchanger.

FIG. 5 is a graphic diagram showing the distribution of heat transfer coefficient in a reactor manufactured in each of Comparative Example 1 and Example 1.

FIG. 6 is a graphic diagram showing the internal temperature distribution of reaction tubes in a reactor manufactured in each of Comparative Example 1 and Example 1.

FIG. 7 is a graphic diagram showing the distribution of heat transfer coefficient in a reactor manufactured in each of Comparative Example 2 and Example 2.

FIG. 8 is a graphic diagram showing the internal temperature distribution of a reaction tube in a reactor manufactured in each of Comparative Example 2 and Example 2.

FIG. 9 is a cross-sectional view illustrating the structure of a plurality of small-diameter rod-type baffles or non-reaction tubes, which can be used instead of one non-reaction tube shown in FIG. 4.

FIG. 10 is a schematic diagram showing the structure of a non-reaction tube having heat medium inlet or outlet passages for improving heat transfer efficiency and/or adjusting the temperature of the heat transfer medium at a specific point in the reactor shell.

Claims

1. A shell-and-tube reactor or heat exchanger comprising: first tubes, through the inside of which a first object for heat transfer with a heat transfer medium is passed, some of the first tubes being provided in a zone in which a flow of the heat transfer medium (parallel flow) parallel to the axis of the tubes is present; anda second tube, through the inside of which the first object is not passed, the second tube being provided in said zone such that it is parallel to the axis of the first tubes.

2. The shell-and-tube reactor or heat exchanger of claim 1, wherein the second tube includes two or more passages for the inlet or outlet of the heat transfer medium.

3. The shell-and-tube reactor or heat exchanger of claim 1, wherein the parallel flow is formed in the central portion of the reactor or heat exchanger, and the second tube is provided in the central portion.

4. The shell-and-tube reactor or heat exchanger of claim 1, wherein a doughnut-type baffle plate and a disc-type baffle plate are alternately provided such that the heat transfer medium flows in an S-shape, and a parallel flow is formed inside of the doughnut-type baffle plate.

5. The shell-and-tube reactor or heat exchanger of claim 1, wherein the diameter D1 of the second tube is in a range of 5-25% of the inner diameter D4 of the shell of the reactor or heat exchanger.

6. The shell-and-tube reactor or heat exchanger of claim 4, wherein the inside diameter D3 of the doughnut-type baffle plate is in a range of 20-50% of the inner diameter D4 of the shell of the reactor or heat exchanger.

7. The shell-and-tube reactor or heat exchanger of claim 4, wherein the inside diameter D2 of the zone, in which the first tubes are present, is adjusted such that the distance from the second tube, i.e., (D2−D1)/2, wherein D1 is the diameter of the second tube, is in a range of 0.5-10% of the inner diameter D4 of the shell of the reactor or heat exchanger, and the distance from the doughnut-type baffle plate, i.e., (D3−D2)/2, wherein D3 is the inside diameter of the doughnut-type baffle plate, is in a range of 3-20% of D4.

8. The shell-and-tube reactor or heat exchanger of claim 2, wherein at least one of the passages for the inlet or outlet of the heat transfer medium is located at a point where temperature peak in the first tubes appears.

9. The shell-and-tube reactor or heat exchanger of claim 2, wherein two or more baffle plates for adjusting the flow of the heat transfer medium are provided in the reactor or heat exchanger, and assuming that the spacing distance between baffle plates in a zone, in which the passage for the inlet or outlet of the heat transfer medium is provided, is L, the size of the passage for the inlet or outlet of the heat transfer medium is 50% or less of the surface area of the second tube corresponding to the distance L.

10. The shell-and-tube reactor or heat exchanger of claim 1, wherein the second tube is provided in a number of two or more in one zone in which the parallel flow is present.

11. The shell-and-tube reactor or heat exchanger of claim 10, wherein the second tubes are symmetrically arranged with respect to the central point thereof.

12. The shell-and-tube reactor or heat exchanger of claim 11, wherein the second tubes are arranged at a central interval of 1.2-1.4 times the outer diameter thereof.

13. The shell-and-tube reactor or heat exchanger of claim 10, wherein the second tubes located at the outermost portion have two or more passages for the inlet or outlet of the heat transfer medium.

14. The shell-and-tube reactor or heat exchanger of claim 1, wherein the first object for heat transfer with the heat transfer medium is a reactant(s) before chemical or physical reaction, a product(s) after the reaction, or a mixture thereof.

15. A method for producing an oxide, comprising: using a shell-and-tube reactor or heat exchanger set forth in claim 1, in which some of first tubes, through the inside of which a first object for heat transfer with a heat transfer medium is passed, are provided in a zone in which a flow of the heat transfer medium (parallel flow) parallel to the axis of the tubes is present, and a second tube, through the inside of which the first object is not passed, is provided in said zone such that it is parallel to the axis of the first tubes; andcausing a catalytic vapor-phase oxidation reaction in first tubes.

16. The method of claim 15, wherein the oxide is unsaturated aldehyde or unsaturated fatty acid.

17. The method of claim 15, wherein the second tube includes two or more passages for the inlet or outlet of the heat transfer medium.

18. The method of claim 15, wherein a doughnut-type baffle plate and a disc-type baffle plate are alternately provided such that the heat transfer medium flows in an S-shape, and a parallel flow is formed inside of the doughnut-type baffle plate.

19. The method of claim 15, wherein the second tube is provided in a number of two or more in one zone in which the parallel flow is present.

20. A method for increasing the heat transfer coefficient of first tubes, through the inside of which a first object for heat transfer with a heat transfer medium is passed, the first tubes being provided in a zone in which a flow of the heat transfer medium (parallel flow) parallel to the axis of the tubes is present, the method comprising increasing the flow rate of the parallel flow by placing a second tube, through the inside of which the first object is not passed, in said zone such that the second tube is parallel to the axis of the first tubes.