Cogeneration system

Patent metadata

Field	Value
Publication number	US-11506115-B2
Application number	US-202016778555-A
Country	US
Kind code	B2
Filing date	Jan 31, 2020
Priority date	Feb 4, 2019
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

The invention provides a cogeneration system capable of adjusting a heat-to-electric power ratio not only in an increasing direction, but also in a decreasing direction. The cogeneration system includes: a power generation device configured to supply electric power; a first heat exchanger configured to exchange heat between exhaust of the power generation device and water, so as to lower a temperature of the exhaust and obtain steam from the water; a reformer configured to generate a reformed gas by the steam reacting with a fuel; a second heat exchanger configured to cool the reformed gas generated by the reformer by heat exchanging; a reformed gas supply device configured to supply the reformed gas cooled by the second heat exchanger to the power generation device; a distributor configured to supply the steam to at least one of the reformer and a heat utilization device; and a control device configure to adjust a heat-to-electric power ratio by changing a supply destination of the steam in the distributor.

First claim

What is claimed is:

1. A cogeneration system comprising:
a power generation device configured to supply electric power;
a first heat exchanger configured to exchange heat between exhaust of the power generation device and water, so as to lower a temperature of the exhaust and obtain steam from the water;
a reformer configured to generate a reformed gas by the steam reacting with a fuel;
a second heat exchanger configured to cool the reformed gas generated by the reformer by heat exchanging;
a reformed gas supply device configured to supply the reformed gas cooled by the second heat exchanger to the power generation device;
a distributor configured to supply the steam to at least one of the reformer and a heat utilization device; and
a control device configure to adjust a heat-to-electric power ratio in an increasing direction and in a decreasing direction based on a heat quantity required by changing a supply destination of the steam in the distributor.

2. The cogeneration system according to claim 1 , wherein
the control device is configured to change a supply amount of the steam in the distributor.

3. The cogeneration system according to claim 1 , wherein
the control device is configured to control the distributor based on the heat quantity, which is required by the heat utilization device.

4. The cogeneration system according to claim 1 , further comprising:
a water supply device configured to supply the water to the first heat exchanger, wherein
the control device is configured to control the water supply device based on a temperature of the steam at an outlet of the first heat exchanger.

5. The cogeneration system according to claim 4 , further comprising:
a third heat exchanger configured to exchange heat between at least a part of the water supplied to the first heat exchanger and a cooling liquid that cools the power generation device, so as to raise a temperature of the water and to lower a temperature of the cooling liquid.

6. The cogeneration system according to claim 1 , further comprising:
a fuel flow control valve configured to adjust an amount of the fuel supplied to the reformer, wherein
the fuel flow control valve is controlled based on an amount of the steam supplied from the distributor to the reformer.

7. The cogeneration system according to claim 6 , wherein
the power generation device is an engine generator using a reciprocating engine,
the fuel is methane, and
the fuel flow control valve is controlled, such that a ratio of the number of moles of the steam supplied to the reformer to the number of moles of carbon atoms contained in the fuel supplied to the reformer is 5 or more.

8. The cogeneration system according to claim 1 , wherein
the power generation device is an engine generator or a turbine generator.

9. The cogeneration system according to claim 1 , wherein
the power generation device is an engine generator using a reciprocating engine, and
the fuel is methane.

10. The cogeneration system according to claim 1 , further comprising:
another distributor configured to supply water heated by the second heat exchanger to at least one of the heat utilization device and the first heat exchanger.

Assignees

• Hitachi Ltd

Inventors

• SHIRAKAWA Yuzo
• Naito Hiroto
• Ishikawa Takao

Classifications

• F02B43/12 Primary

  Methods of operating · CPC title

• F02D19/0671

  Means to generate or modify a fuel, e.g. reformers, electrolytic cells or membranes · CPC title

• F02G5/02

  Profiting from waste heat of exhaust gases · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02M31/205 Primary

  Control · CPC title