US3727564A

US3727564A - Modulated fuel

Info

Publication number: US3727564A
Application number: US00181142A
Authority: US
Inventors: R Stockman; W Anderson; H Liu
Original assignee: Air Preheater Co Inc
Current assignee: Enercon Systems Inc
Priority date: 1971-09-09
Filing date: 1971-09-09
Publication date: 1973-04-17
Anticipated expiration: 1990-04-17

Abstract

An incinerator system is disclosed including a primary combustion chamber for the pyrolysis of combustible material and a serially connected secondary combustion chamber for complete combustion of the gas produced by pyrolysis in the primary combustion chamber. An independent fuel supply is provided and its flow to the secondary combustion chamber is continuously modulated to supplement the gas being supplied thereto by pyrolysis of combustible material in the primary chamber to provide a substantially constant flow of fuel to the secondary combustion chamber that burns at a uniform rate and temperature.

Description

United States Patent [191 Anderson et al.

[ MODULATED FUEL [75] Inventors: William M. Anderson; Han Liu, both of Wellsville; Richard F. Stockman, Friendship, all of NY.

[73] Assignee: The Air Preheater Company, Inc., Wellsville,N.Y.

[22] Filed: Sept. 9, 1971 [21] Appl.No.: 181,142

110/8 C, 18 R, 18 C [4 1 Apr. 17, 1973 7/1956 Shortetal. ..1l0/8A 7/1971 Andersonetal. ..1l0/8 Primary Examiner-Kenneth W. Sprague Attorney-Wayne H. Lang et a1. i

[5 7 ABSTRACT An incinerator system is disclosed including a primary combustion chamber for the pyrolysis of combustible material and a serially connected secondary combustion chamber for complete combustion of the gas produced by pyrolysis in the primary combustion chamber. An independent fuel supply is provided and its flow to the secondary combustion chamber is continuously modulated to supplement the gas being supplied thereto by pyrolysis of combustible material in the primary chamber to provide a substantially constant flow of fuel to the secondary combustion chamber that burns at a uniform rate and tempera- 3 Claims, 1 Drawing Figure [56] References Cited UNITED STATES PATENTS ture. 1,995,723 3/1935 Van Denburg ..1 10/8 A 3,491,707 1/1970 Bakker ..1 10/8 A PAIENTEDAPR 1 1 1m 3'. 727. 564

IN'VENTOR.

MODULATEI) FUEL BACKGROUND OF THE INVENTION primary combustion chamber, gas is produced therein from the partial combustion of organic waste material and then exhausted into the secondary chamber for complete combustion. Non-combustible exhaust gases alone are vented into the atmosphere.

2. Description of Prior Art Incineration of waste materials in an incinerator of the starved air type is a well known and effective method of waste incineration. In a starved air" process, gases from the incineration of solids are produced and only partially burned in a main combustion zone supplied with insufficient oxygen, the unburned gases being subjected to further combustion in another zone having an adequate supply of oxygen for complete combustion as shown by U. S. Pats. No. 3,491,707 and No. 3,493,645.

To insure the complete combustion of organic material in the secondary combustion chamber before waste exhaust gases are vented therefrom into the atmosphere, one or more afterburners are frequently utilized to improve the efficiecy of combustion. The afterburners are usually supplied with an independent source of fuel that traverses a fuel line having a single off-on type of control. Since any abrupt change in the quantity or type of fuel being charged into the primary chamber and even normal starting and stopping operations lead to a variation in the combustion rate and to a rapid increase or decrease in the incinerator chamber temperature when the gaseous mixture passes through stoichiometric proportions, the degree of combustion in the secondary combustion chamber may vary widely during a normal burning cycle. Improper combustion of gases or any other unsatisfactory operation will result in the exhaust of visible gases into the atmosphere. It has been proposed that air for combustion of the gas being supplied to the primary combustion chamber and to the secondary combustion chamber be controlled to assure complete combustion. However, any variation in the type or amount of waste being burned, or in the auxiliary fuel being supplied will still provide a variation in the combustion rate that results in incomplete combustion and an unacceptable puff of visible smoke being exhausted into the atmosphere whenever a change of conditions occurs.

SUMMARY OF THE INVENTION The present invention relates to a starved air" type incinerator with a primary and a secondary combustion chamber having an auxiliary source of fuel supplied to the secondary combustion chamber that varies constantly to comlement the constantly changing amount of fuel being produced in the primary combustion chamber by pyrolysis of the waste material placed therein. Therefore, by the arrangement according to this invention, the amount of auxiliary fuel being supplied to the secondary combustion chamber varies constantly to supplement the varying amounts of gas exhausting from the primary chamber to thus insure that the total amount of fuel being supplied, the rate of combustion and the temperature in the secondary combustion chamber will be maintained substantially constant throughout wide variations in the supply of gas produced by pyrolysis in the primary combustion chamber. Thus, a continuously high temperature will result, complete combustion is assured and no visible smoke will exhaust to the atmosphere.

BRIEF DESCRIPTION OF THE DRAWING A better understanding of the invention may be had by reference to the drawing in which:

The single FIGURE is a side elevation of an incinerator which shows the primary and a secondary combustion chamber with the controls necessary to provide a modulated fuel system.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings of the present invention, the reference 10 designates a combustion vessel enclosing a primary combustion chamber lll having a gas outlet port 12 at one end thereof and a waste inlet door 14 pivotally supported at the other. The inner wall of the vessel 10 is suitably insulated by a layer of fire resistant material 16 that directly confronts the interior of the combustion chamber. The bottom of the combustion vessel 10 is adapted to receive one or more apertured air supply tubes 18 to supply the air necessary for the combustion charge placed therein.

The tubes 18 are connected to an outside source of air 26 by an air supply duct 27. A valve 28 that responds to the temperature at thermocouple 29 and controller 30 is continuously movable through an infinite number of settings from full-open" to full closed" position to regulate the flow of air so that a precise modulation of air flow is achieved at all times. An outlet stack 32 is connected to the outlet port 12 leading from the main combustion chamber. The stack 32 contains a secondary combustion chamber 35 having a separate burner including a source of fuel 37 and a connecting line 39 to source of air 26 controlled by valve means 40.

When a charge of waste material to be incinerated is placed in the primary combustion chamber and combustion therein is commenced, the usual sequence followed is for the temperature in the primary combustion chamber to slowly increase and then decline until pyrolysis of the charge is complete. Gas produced by pyrolysis in the primary combustion chamber 11 and exhausted through outlet 12 into the secondary combustion chamber 35 will similarly vary greatly so that the temperature within the secondary combustion chamber will fluctuate widely and there will be incomplete combustion with the result that there will be periodic bursts of visible smoke exhausting into the atmosphere whenever the combustion is less than complete.

Therefore, this invention provides for an independent source of fuel to be variably supplied to the secondary combustion chamber 35 to supplement the gas being supplied by pyrolysis of the waste material in the primary combustion chamber 11. The supplementary flow of fuel is continuously modulated by a control valve 42 to provide a uniform total amount of fuel that burns with a constant temperature in the stack 32. The control valve 42 responds to a controller 44 that is set to provide a constant temperature at thermocouple 46. Thus, when gas supplied by pyrolysis of fuel in the primary chamber decreases, the supplementary flow of fuel to the secondary chamber increases whereby the total amount of gas available in the secondary combustion chamber remains substantially constant, and the temperature at thermocouple 46 remains unchanged.

Inasmuch as the thermocouple 46 in the outlet stack calls for a constant temperature, the heat content of the gas produced by pyrolysis in the primary combustion chamber or that of the supplementary fuel being supplied to the secondary combustion chamber may vary significantly without altering the operation of our device Other factors may vary while substitutions and modifications may be made without departing from the intent of the present invention. It is to be understood therefore, that the details of the incinerator including its size and relationship of the various elements are to be limited only by the scope of the appended claims.

We claim:

1. An incinerator with a primary combustion changer having an opening for the loading of combustible material and an opening for the exhaust of the gaseous products of combustion therefrom, a secondary combustion chamber having inlet and outlet openings, means connecting the inlet of the secondary combustion chamber to the opening exhausting products of combustion from the primary combustion chamber, an auxiliary source of fuel, means for directing fuel from said source to the secondary combustion chamber, a modulating valve for controlling the flow of fuel from the auxiliary source to the secondary combustion chamber, a timing device, and means responsive to said timing device modulating the flow of fuel through the valve to the secondary combustion chamber.

2. An incinerator for burning combustible waste material comprising a primary combustion chamber having an inlet opening for combustible material and an outlet port for gases of combustion exhausting therefrom, a passageway including a secondary combustion chamber, means closing the inlet opening to the primary combustion chamber, air supply means connected to the primary and to the secondary combustion chambers, valve means continuously modulating the flow of air to the primary combustion chamber, an auxiliary source of fuel, a fuel supply duct connecting the auxiliary source of fuel to the secondary combustion chamber, valving means in said fuel duct modulating the flow of fuel therethrough, a thermocouple responsive to temperature in the secondary combustion chamber, and means responsive to said thermocouple for regulating the valve in the fuel line connecting said source of fuel to the secondary combustion chamber in inverse ratio to the flow of combustible gas from the primary to the secondary combustion chambers.

3. An incinerator with a primary combustion chamber having an opening for the loading of combustible material and an opening for the exhaust of the gaseous products of combustion therefrom, a secondary combustion chamber having an inlet and outlet openings, means connecting the inlet of the secondary combustion chamber to the opening exhausting products of combustion from the Primary combustion chamber, an auxiliary source of fuel, means for directing fuel from said source to the secondary combustion chamber, a modulating valve for controlling the flow of fuel from the auxiliary source to the secondary combustion chamber, a thermocouple adjacent the outlet of the secondary combustion chamber, and means responsive to said thermocouple continuously modulating the auxiliary fuel control valve to provide continuously controlled combustion in the secondary combustion chamber.