Method and system for generating energy during the expansion of natural process gas

Patent metadata

Field	Value
Publication number	US-9885239-B2
Application number	US-201314427155-A
Country	US
Kind code	B2
Filing date	Sep 17, 2013
Priority date	Sep 18, 2012
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

Provided is a method for energy recuperation in the expansion of processed natural gas before the delivery of the latter to an acetylene production plant (H). The method includes delivery of heated processed natural gas to an expansion device and expansion of the processed natural gas in the expansion device to a pressure of 2 bar to 8 bar. The expansion device is a piston expansion machine which is operated by the expansion of the processed natural gas and which generates energy. Also provided is a plant for energy recuperation in the expansion of processed natural gas.

First claim

The invention claimed is:

1. A method for energy recuperation in the expansion of processed natural gas during delivery to an acetylene production plant, comprising:
a) delivering a processed natural gas from a processed natural gas supply line, wherein the processed natural gas has a temperature of −10° C. to 50° C. and a pressure of 30 bar to 70 bar, to a first heating stage and heating the processed natural gas in the first heating stage to a temperature of 20° C. to 40° C.,
b) delivering the processed natural gas heated in the first heating stage to a second heating stage and heating the processed natural gas in the second heating stage to a temperature of 70° C. to 140° C.,
c1) delivering the processed natural gas heated in the second heating stage to a first expansion stage of a piston expansion machine, wherein the piston expansion machine operates by the expansion of the processed natural gas and which generates energy, and expanding the processed natural gas in the first expansion stage to a pressure of 15 bar to 25 bar, wherein the processed natural gas has a temperature of 15° C. to 25° C. after the expansion in the first expansion stage,
c2) delivering the processed natural gas expanded in the first expansion stage to a third heating stage and heating the processed natural gas in the third heating stage to a temperature of 70° C. to 140° C.,
c3) delivering the processed natural gas heated in the third heating stage to a second expansion stage of the piston expansion machine and expanding the processed natural gas in the second expansion stage of the piston expansion machine to a pressure of 2 bar to 8 bar, wherein the processed natural gas has a temperature of 10° C. to 100° C. after the expansion in the second expansion stage,
d) delivering the processed natural gas expanded in the second expansion stage of the piston expansion machine to a fourth heating stage and heating the processed natural gas in the fourth heating stage to a temperature of 40° C. to 100° C., wherein the processes natural gas has a pressure of 2 bar to 8 bar after the heating in the fourth heating stage, and
e) delivering the processed natural gas having a pressure of 2 bar to 8 bar heated in the fourth heating stage to an acetylene production plant,
wherein at least a portion of waste heat from the second heating stage and the third heating stage heats the processed natural gas in the fourth heating stage.

2. The method according to claim 1 , wherein the piston expansion machine operates by the expansion of the processed natural gas driving a generator that generates electrical energy.

3. The method according to claim 1 , wherein the heating of the processed natural gas in at least one stage selected from the group consisting of the first heating stage, the second heating stage, the third heating stage, and the fourth heating stage is performed in a plate heat exchanger.

4. The method according to claim 1 , wherein the processed natural gas is heated to a temperature of 25° C. to 35° C. in the first heating stage.

5. The method according to claim 1 , wherein the processed natural gas is heated to a temperature of 75° C. to 85° C. in the second heating stage.

6. The method according to claim 1 , wherein the processed natural gas is expanded to a pressure of 19 bar to 22 bar in the first expansion stage.

7. The method according to claim 1 , wherein the processed natural gas is expanded to a pressure of 4 bar to 6 bar in the second expansion stage.

8. The method according to claim 2 , wherein at least a portion of waste heat from the generator heats the processed natural gas in the first heating stage.

9. The method according to claim 1 , wherein the piston expansion machine is of at least two-stage design.

10. The method according to claim 1 , wherein the piston expansion machine comprises a double-acting piston.

11. A plant for energy recuperation during the expansion of processed natural gas, comprising:
a processed natural gas supply line,
a first heating stage suitable for heating a processed natural gas, wherein the first heating stage is connected to the processed natural gas supply line via a feed line,
a second heating stage suitable for heating the processed natural gas heated by the first heating stage, wherein the second heating stage is connected to the first heating stage via a line,
a piston expansion machine suitable for expanding the processed natural gas heated by the second heating stage, and comprising a first expansion stage and a second expansion stage, wherein the piston expansion machine is connected to the second heating stage via a line,
a third heating stage between the first expansion stage and the second expansion stage, wherein the third heating stage is connected to the first expansion stage via a line and is connected to the second expansion stage via a line, and
a fourth heating stage suitable for heating the processed natural gas expanded in the second expansion stage of the piston expansion machine, wherein the fourth heating stage is connected to the second expansion stage via a line,
wherein
the second heating stage is connected to the fourth heating stage via a waste heat line,
the third heating stage is connected to the fourth heating stage via a waste heat line, and
the plant is connectable via one or more lines to an acetylene production plant.

12. The plant according to claim 11 , wherein the piston expansion machine is connected to a generator configured for generating electrical energy.

13. The plant according to claim 11 , wherein at least one stage selected from the group consisting of the first heating stage, the second heating stage, the third heating stage, and the fourth heating stage comprises a plate heat exchanger.

14. The plant according to claim 12 , wherein:
(i) the first heating stage is connected via a waste heat line to the generator,
(ii) the second heating stage is connectable via a waste heat line to the acetylene production plant,
(iii) the third heating stage is connectable via a waste heat line to the acetylene production plant,
(iv) the fourth heating stage is connected via waste heat lines to the second heating stage and the third heating stage,
or any combination of (i), (ii), (iii) and (iv).

15. The plant according to claim 11 , wherein the piston expansion machine is of at least two-stage design.

16. The plant according to claim 11 , wherein the piston expansion machine comprises a double-acting piston.

Assignees

• Basf Se

Inventors

• Haider Mirko
• Brostean Thomas

Classifications

• F02C1/04

  the working fluid being heated indirectly {(in a fluidised-bed combustor F02C3/205)} · CPC title

• F01B31/08 Primary

  Cooling of steam engines; Heating; Heat insulation · CPC title

• Y02E20/14

  Combined heat and power generation [CHP] · CPC title

• F02M25/10

  adding acetylene, non-waterborne hydrogen, non-airborne oxygen, or ozone · CPC title

• F01K17/04

  for specific purposes other than heating (F01K17/06 takes precedence) · CPC title