Reactor heating to achieve minimum pressurization temperature

Patent metadata

Field	Value
Publication number	US-11298672-B2
Application number	US-202016996999-A
Country	US
Kind code	B2
Filing date	Aug 19, 2020
Priority date	Oct 16, 2019
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

Systems and methods are provided for performing the initial heating phase for a thick wall reactor, such as a hydroprocessing reactor, by using heat tracing to heat the exterior walls of the reactor. Instead of attempting to initially heat the reactor by passing a low pressure heat transfer gas through the interior of the reactor, external heater(s) placed under the reactor insulation can be used to heat the exterior of the reactor. An example of a suitable external heater is a heat tracing blanket, where heat is provided by passing steam through pipes in contact with the external surface or by electrical heaters in contact with the external surface. This can allow for more rapid heating of the reactor, so that a target temperature can be achieved in a time of 5.0 hours or less.

First claim

The invention claimed is:

1. A method for starting up a reactor, comprising:
heating a reactor wall of a reactor from an initial temperature of less than 70° C. to a first temperature of 95° C. or more by heating an external wall surface of the reactor wall using heat tracing, a pressure in the reactor being 2.0 MPa-g or less during the heating;
passing a pressurizing gas flow into the reactor to increase the pressure in the reactor by 0.5 MPa or more; and
passing a heated gas flow into the reactor to increase the temperature of the reactor wall by 50° C. or more relative to the first temperature.

2. The method of claim 1 , wherein at least a portion of the pressurizing gas flow comprises the heated gas flow.

3. The method of claim 1 , wherein the heat tracing comprises electrical heat tracing, steam heat tracing, or a combination thereof.

4. The method of claim 1 , wherein the heat tracing is inactive during the passing of the heated gas flow into the reactor.

5. The method of claim 1 , wherein a supplemental gas flow is passed into the reactor during the heating of the reactor wall using the heat tracing, the supplemental gas flow comprising a temperature greater than the initial temperature.

6. The method of claim 1 , wherein the external wall surface is heated to a second temperature that is greater than the first temperature by 10° C. to 50° C.

7. The method of claim 1 , wherein the reactor wall comprises a thickness of 2.5 cm or more.

8. The method of claim 1 , wherein the heating using the heat tracing is performed for 5 hours or less.

9. The method of claim 1 , wherein the reactor comprises a hydroprocessing reactor.

10. The method of claim 1 , wherein passing the pressurized gas flow into the reactor increases the pressure to 3.4 MPa-g or more, or wherein passing the heated gas flow into the reactor increases the temperature of the reactor wall to 250° C. or more, or a combination thereof.

11. The method of claim 1 , further comprising exposing a feedstock to a pressure of 2.0 MPa-g or more and a temperature of 250° C. or more in the presence of H 2 in the reactor to form a hydroprocessed product.

12. The method of claim 1 , wherein the reactor wall comprises a reactor wall that has previously been exposed to a partial pressure of H 2 at a temperature of 250° C. or more and a pressure of 2.0 MPa-g or more.

13. A method for starting up a reactor, comprising:
heating a reactor wall of a reactor from an initial temperature of less than 70° C. to a first temperature of 95° C. to 160° C. by heating an external wall surface of the reactor wall using heat tracing, a pressure in the reactor being 2.0 MPa-g or less during the heating;
passing a pressurizing gas flow into the reactor to increase the pressure in the reactor to 2.5 MPa-g or more; and
passing a heated gas flow into the reactor to increase the temperature of the reactor wall from the first temperature to a temperature of 200° C. or more.

14. The method of claim 13 , wherein at least a portion of the pressurizing gas flow comprises the heated gas flow.

15. The method of claim 13 , wherein the heat tracing comprises electrical heat tracing, steam heat tracing, or a combination thereof.

16. The method of claim 13 , wherein the heat tracing is inactive during the passing of the heated gas flow into the reactor, or wherein a supplemental gas flow is passed into the reactor during the heating of the reactor wall using the heat tracing, the supplemental gas flow comprising a temperature greater than the initial temperature.

17. The method of claim 13 , wherein the external wall surface is heated to a second temperature that is greater than the first temperature by 10° C. to 50° C., and wherein the second temperature is 105° C. to 200° C.

18. The method of claim 13 , wherein the reactor wall comprises a thickness of 2.5 cm or more.

19. The method of claim 13 , wherein the heating using the heat tracing is performed for 5 hours or less.

20. The method of claim 13 , wherein the reactor comprises a hydroprocessing reactor, the method further comprising exposing a feedstock to a pressure of 2.0 MPa-g or more and a temperature of 250° C. or more in the presence of H 2 in the reactor to form a hydroprocessed product.

Assignees

• Exxonmobil Res & Eng Co

Inventors

• Kiliany Jr Thomas R
• Rajagopalan Suriyanarayanan

Classifications

• B01J2208/00194

  Tubes · CPC title

• B01J8/0285

  Heating or cooling the reactor (for tubular reactors in furnaces B01J8/062) · CPC title

• C10G47/36 Primary

  Controlling or regulating · CPC title

• B01J2208/00415

  electric resistance heaters · CPC title

• B01J19/0013 Primary

  Controlling the temperature of the process · CPC title