Steam generator for fuel cell applications

Patent metadata

Field	Value
Publication number	US-11476480-B2
Application number	US-201715710591-A
Country	US
Kind code	B2
Filing date	Sep 20, 2017
Priority date	Sep 20, 2017
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

A steam vaporizer assembly includes an internal steam generator having a vessel configured to hold water, a vaporizer unit having a heating element configured to heat the water to generate saturated steam; and a controller configured to: cause the heating element to heat the water to a stand-by temperature; and while maintaining a water level of the water in the vessel between two control points: maintain the water in the vessel at the stand-by temperature until steam generation is required, and when steam generation is required, heating the water in the vessel from the stand-by temperature to a temperature at or above a vaporization temperature of the water using a heating element, to generate the steam.

First claim

What is claimed is:

1. A method of producing steam in a fuel cell system, the method comprising: providing an internal steam generator that comprises a vessel; and opening a water feed valve to allow water into the vessel when the water level drops below a lower control point, and closing the water feed valve when the water level reaches an upper control point, thereby maintaining a water level of the water in the vessel between the lower control point and the upper control point, while the fuel cell system is producing power in a water neutral mode, maintaining the water in the vessel at a stand-by temperature between about 80° C. and about 90° C., and while the fuel cell system is not producing power in a water neutral mode, heating the water in the vessel from the stand-by temperature to a temperature at or above a vaporization temperature of the water using a heating element to generate steam, and using the steam in a reforming reaction within the fuel cell system, wherein the fuel cell system producing power in a water neutral mode corresponds to the fuel cell system producing 30% or more power load, and wherein the fuel cell system not producing power in a water neutral mode corresponds to the fuel cell system producing less than 30% power load.

2. The method of claim 1 , wherein the heating element is a low power density heater.

3. The method of claim 2 , wherein the heating element is an inductive heating coil positioned around the vessel exterior.

4. The method of claim 1 , wherein the steam is generated at generation rate of between 10 lb/hr and 40 lb/hr.

5. The method of claim 1 , wherein the water level is monitored in a water level tube fluidly coupled to the vessel.

Assignees

• Fuelcell Energy Inc

Inventors

• Dobek Frank
• Jolly Stephen
• Davis Keith

Classifications

• H01M8/04037

  Electrical heating · CPC title

• H01M8/0618

  Reforming processes, e.g. autothermal, partial oxidation or steam reforming · CPC title

• F22B33/18

  Combinations of steam boilers with other apparatus · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• F22B1/284 Primary

  with water in reservoirs · CPC title