# US 12,372,312 B2 · Thermal cracking tube with fluid agitating element

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- Number: US 12,372,312 B2
- Document ID: US12372312B2
- Status: Granted
- Kind: B2
- Application number: 17/613,639
- Filed: 2021-06-21
- Published: 2022-10-06
- Granted: 2025-07-29
- Earliest claimed: 2020-06-29
- Assignees: Kubota Corporation
- Applicants: Kubota Corporation
- Inventors: Motoyuki Matsubara; Kunihide Hashimoto; Toru Sukawa
- Web page: https://patentgrep.com/patent/US12372312B2

## CPC

- F28F 1/40: the means being only inside the tubular element
- B01J 19/0013: {Controlling the temperature of the process}
- B01J 19/006: {Baffles}
- B01J 19/2405: {provoking a turbulent flow of the reactants, such as in cyclones, or having a high Reynolds-number}
- C10G 9/14: in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
- F28F 13/12: by creating turbulence, e.g. by stirring, by increasing the force of circulation (F28F13/08 takes precedence)
- B01J 2219/00164: controlling the flow
- F28D 2021/0022: {for chemical reactors}
- F28D 2021/0056: {for ovens or furnaces}
- F28D 2021/0059: {for petrochemical plants}
- F28D 2021/0075: {for syngas or cracked gas cooling systems}
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)

## Abstract

The present invention provides a thermal cracking tube formed with an agitating element that has a good agitation effect and improves heat transfer efficiency while minimizing an increase in the pressure loss of the fluid flowing through the cracking tube. A thermal cracking tube 10 with an agitating element of the present invention is a thermal cracking tube having a tube axis with one end and the other end, wherein a fluid inlet is on the one end and a fluid outlet is on the other end, the tube being provided on an inner surface thereof with one or more fluid agitating elements 20 extending from the inner surface of the tube and having an inwardly facing top portion, wherein the agitating element is helically inclined to or is orthogonal to a longitudinal direction of the tube axis, and the top portion deviates to the fluid inlet side 11 or the fluid outlet side 12, relative to a center 0 of a width direction of the agitation element.

## Claims

### Claim 1

A thermal cracking tube with an agitating element to be heated from outside, the thermal cracking tube comprising,
a tube having a tube axis with one end and another end, wherein a fluid inlet is on the one end and a fluid outlet is on the another end, the tube having an inner surface with a diameter of at least about 30 mm and being configured to thermally crack a hydrocarbons-containing feedstock fluid material over a reaction temperature range, and
at least one agitating element for agitating the feedstock fluid material, wherein the agitating element is provided on the inner surface of the tube and extends inwardly from the inner surface of the tube and has an inwardly facing top portion,
wherein
the agitating element is helically inclined to or is orthogonal to a longitudinal direction of the tube axis, and has oppositely inclined surfaces across the top portion thereof,
the oppositely inclined surfaces comprise an inlet-side inclined surface on the fluid inlet side and an outlet-side inclined surface on the fluid outlet side,
when the agitating element is viewed in a sectional plane including the tube axis, the top portion of the agitating element is located on the fluid inlet side or the fluid outlet side, relative to a center of a width of the agitating element, wherein
(1) the inlet-side inclined surface has a concave shape and the outlet-side inclined surface has a convex shape, or
(2) the inlet-side inclined surface has a convex shape and the outlet-side inclined surface has a concave shape.

### Claim 2 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the top portion of the agitating element is located on the fluid inlet side by at least 10% or to the fluid outlet side by at least 5%, relative to the distance from a peak of the top portion to the center of the width of the agitating element.

### Claim 3 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the top portion of the agitating element is located on the fluid inlet side by up to 90% or to the fluid outlet side by up to 85%, relative to the distance from a peak of the top portion to the center of the width of the agitating element.

### Claim 4 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the inlet-side inclined surface and the outlet-side inclined surface are different in their inclined angles.

### Claim 5 (depends on 2)

The thermal cracking tube with an agitating element according to claim 2, wherein the inlet-side inclined surface and the outlet-side inclined surface are different in their inclined angles.

### Claim 6 (depends on 3)

The thermal cracking tube with an agitating element according to claim 3, wherein the inlet-side inclined surface and the outlet-side inclined surface are different in their inclined angles.

### Claim 7 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the inclined surface of the convex shape or the concave shape further includes at least one projected part or recessed part.

### Claim 8 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the agitating element has a length longer in the longitudinal direction than the width direction.

### Claim 9 (depends on 2)

The thermal cracking tube with an agitating element according to claim 2, wherein the agitating element has a length longer in the longitudinal direction than the width direction.

### Claim 10 (depends on 3)

The thermal cracking tube with an agitating element according to claim 3, wherein the agitating element has a length longer in the longitudinal direction than the width direction.

### Claim 11 (depends on 1)

The thermal cracking tube with an agitating element according to claim 1, wherein the top portion has a flat surface wherein a center in the width direction of the flat surface deviates to the fluid inlet side or the fluid outlet side.