# US 4,499,857 A · Fluidized bed fuel burning

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- Number: US 4,499,857 A
- Document ID: US4499857A
- Status: Granted
- Kind: A
- Application number: 06/542,646
- Filed: 1983-10-17
- Granted: 1985-02-19
- Earliest claimed: 1983-10-17
- Assignees: Wormser Engineering, Inc.
- Inventors: Alex F. Wormser
- Web page: https://patentgrep.com/patent/US4499857A

## CPC

- F22B 31/0023: {with tubes in the bed (F22B31/003 takes precedence)}
- F23C 10/005: {comprising two or more beds}
- F22B: METHODS OF STEAM GENERATION; STEAM BOILERS
- F23C: METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN {A CARRIER GAS OR} AIR (burners F23D)

## Abstract

Controlling a fluidized bed coal combustor by sensing certain variables and thereby controlling other variables.

## Claims

### Claim 1

A method of burning coal comprising
burning coal in a first fluidized bed chamber having tubes carrying steam heated therein, said tubes not being covered when said bed is not fluidized and being covered when said bed is fully fluidized,
treating the gaseous products of combustion from said first fluidized bed in a second fluidized bed to provide a treated stack gas,
controlling the rate of airflow into said first fluidized bed based upon the pressure of steam in said tubes,
controlling the ratio of the rate of airflow to the rate of feeding coal based upon the concentration of oxygen in said stack gas, and
controlling the level of solids in said first fluidized bed based upon the combustion bed temperature in said first fluidized bed.

### Claim 2

A method of burning coal comprising
burning coal in a first fluidized bed chamber having tubes carrying steam heated therein, said tubes not being covered when said bed is not fluidized and being covered when said bed is fully fluidized,
controlling the rate of airflow into said first fluidized bed based upon the pressure of steam in said tubes,
controlling the ratio of the rate of air flow to the rate of feeding coal based upon the concentration of oxygen in said stack gas, and
controlling the level of solids in said first fluidized bed based upon the combustion bed temperature in said first fluidized bed.

### Claim 3 (depends on 1)

The method of claim 1 in which a temperature sensor in the second bed regulates the rate of flow of secondary air.

### Claim 4 (depends on 1)

The method of claim 1 in which a sulfur dioxide sensor is provided in the stack.