Booster air heater for high moisture fuels

Patent metadata

Field	Value
Publication number	US-9631809-B2
Application number	US-201615284794-A
Country	US
Kind code	B2
Filing date	Oct 4, 2016
Priority date	Sep 11, 2012
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A system for drying pulverized high moisture fuel for use in a selective catalytic reduction system equipped combustion system is provided. The combustion system includes a mill for pulverizing fuel, an air heater, two fuel gas streams at different temperatures, a booster air heater and a fuel duct for feeding dried pulverized fuel to a combustion furnace.

First claim

What is claimed is:

1. A selective catalytic reduction system equipped combustion system fueled by high moisture fuel comprising:
a mill for pulverizing high moisture fuel to obtain pulverized fuel;
an interior chamber;
an air heater operable to heat primary air to an increased temperature using a first flue gas stream and a second flue gas stream, the second flue gas stream being a portion of the flue gas exiting the interior chamber of the combustion system prior to passing through a heat exchanger and being a higher temperature than the first flue gas stream;
a booster air heater operable to heat primary air of an increased temperature to a higher temperature using the second flue gas stream; and
a fuel duct for passage of higher temperature primary air through the mill to dry the pulverized fuel and to carry the dry pulverized fuel from a mill outlet to a combustion furnace.

2. The system according to claim 1 wherein said high moisture fuel is one or more fuels selected from the group consisting of sub-bituminous coal and lignite.

3. The system according to claim 1 wherein said air heater uses flue gas from a selective catalytic reduction system as a heat source.

4. The system according to claim 3 wherein said flue gas has a temperature in the range of 700° F. to about 750° F. upon entering said selective catalytic reduction system.

5. The system according to claim 3 wherein said flue gas has a temperature in the range of 550° F. to about 650° F. upon entering said catalytic reduction system.

6. The system according to claim 1 wherein said increased temperature is a temperature in the range of 400° F. to about 500° F.

7. The system according to claim 1 wherein said higher temperature is a temperature in the range of 700° F. to about 800° F.

8. The system according to claim 1 wherein said air heater is also operable to heat secondary air to an increased temperature for use as combustion air in said combustion furnace.

9. The system according to claim 1 wherein said primary air temperature at said mill outlet is in the range of 160° F. to about 220° F.

Assignees

• General Electric Technology Gmbh

Inventors

• Darling Scott L
• Saldon Edward S

Classifications

• F23K2201/103

  with hot gas supply · CPC title

• F23K2201/20

  Drying · CPC title

• F23L15/04 Primary

  Arrangements of recuperators · CPC title

• F23K2900/01041

  Heating by using exhaust gas heat · CPC title

• F23D1/005 Primary

  burning a mixture of pulverulent fuel delivered as a slurry, i.e. comprising a carrying liquid · CPC title