US3464375A

US3464375A - Incinerator with fluid turbulator

Info

Publication number: US3464375A
Application number: US652636A
Authority: US
Inventors: James Leon Tarbox
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1967-07-11
Filing date: 1967-07-11
Publication date: 1969-09-02
Anticipated expiration: 1986-09-02

Description

Sept. 2, 1969 J. L. TARBOX INCINERATOR WITH FLUID TURBULATOR Filed July 11, 1967 2 Sheets-Sheet l U m mi INVENTOR. James L. Tarbox ATTORNY$ k MORE Sept 1969 J. L. TARBOX INCINERATOR WIT FLUID TURBULATOR Filed July 11, 1967 2 Sheets-Sheet 2 ATTORNEYS INVENTOR. James L Tarbox United States Patent C) 3,464,375 INCINERATOR WITH FLUID TURBULATOR James Leon Tarbox, Edgewood, Md., assignor tothe United States of America as represented by the Secretary of the Army Filed July 11, 1967, Ser. No. 652,636 Int. Cl. F231 1 7 16'; F23b 1/38 US. Cl. 1107 2 Claims ABSTRACT OF THE DISCLOSURE A fluid turbulator for an incinerator for combustible radioactive waste to provide efficient flue gas cooling and elimination of leakage.

My invention relates to a fluid turbulator for an incinerator for disposal of combustible radioactive wastes.

The advent of nuclear activities has necessitated an incinerator as a means of disposing of combustible radioactive waste. Included in such incinerators there must be a means of air dilution. The air dilution means in the prior art incinerators comprised nothing more than a simple register, similar to heat registers, for bleeding in make-up air for cooling purposes. The make-up air feed must be regulated to obtain the proper air-flue gas mix, and such regulation was diflicult to satisfactorily obtain with the simple register means. Also, a turbulent flow has been found to be the only efficient method to satisfactorily lower the flue gas temperature from about 2000 F. to about 600 F.; the lower temperature being required due to the utilization of mild steel in air dilution means and following component fabrication. A turbulent stream could not be obtained with the prior art register means and bad leakage around the register means were problems encountered with the prior art incinerators.

A principal object of my invention is to provide a reliable air dilution means to regulate bleed in air and to produce turbulent air flow to lower the flue gas temperature.

A further object of my invention is to provide a reliable air dilution means to prevent leakage of radioactive material from the flue gases entering the air dilution means to the environment outside of the incinerator.

Other objects of my invention will be obvious or will appear from the specification hereinafter set forth.

FIGURE 1 is a schematic diagram of the prior art incinerator.

FIGURE 2 is a schematic diagram of my turbulator to show the replacement of the prior art register means in the incinerator by my invention.

FIGURE 3 is a perspective view of the fluid turbulator air dilution means of my invention.

FIGURE 4 is a sectional view taken along line 4-4 of FIGURE 3 to show the contour of battle 28.

FIGURE 5 is a view showing the means for air input into my fluid turbulator.

My invention and FIGURES 1 to 4 will now be described in detail as follows:

FIGURE 1 shows the prior art incinerator comprising a primary combustion chamber 4 and secondary combustion chamber 4 and secondary combustion chamber 9; each constructed of mild steel and lined with 2 /2 inch thick insulating type refractory. The primary overfire air is admitted tangentially into the primary combustion chamber through two inlets 7 approximately 155 degrees apart and 24 inches above grate 5. The primary air inlets consist of 3 inch stainless steel pipes into which specially shaped, annular pipe sections may be inserted so that the effects of velocity variation at constant volumetric flow rate can be studied. Two sets of air inlets, constructed as 3,464,375 Patented Sept. 2, 1969 ice panel insert sections, are provided; one pair being for tangential, horizontal air admission while the other pair being for directing inlet air tangentially downward at a 30 degree angle relative to the horizontal. Secondary combustion air is admitted tangentially through a single 2 inch pipe inlet 8 located about 6% inches above the primary combustion chamber. Annular inserts may also be provided for the secondary air inlet as for the primary air inlet in order to permit velocity variation. The incinerator utilizes continuous auxiliary gas firing by means of burners 11 in both combustion chambers to minimze discharge of unburned materials and to maintain desired operating temperatures up to about 2500 F. The auxiliary gas firing system also serves to preheat the combustion chambers prior to the charging of waste material. Waste material is introduced as packaged charges, 6 to 10 pounds at a time, through a side loading door, not shown in the drawing, in charging box 6. A three-pronged sliding fork, not shown in the drawing, inserted through the loading door permits temporary suspension of wet packaged charges above the grate to facilitate rapid drying. A manually operated protective guillotine door, not shown in the drawing, in conjunction with a totally inclosed charging lock, not shown in the drawing, is provided to eliminate exposure of operating personnel to accidental release of dust or fumes during the charging operation. Ashes drop through the grate openings into a conical ash receiver 3 and are discharged through a rotary valve 2 into a 55 gallon ash drum 1 for storage. A hydraulic jack, not shown in the drawing maintains a tight air seal, between the drum rim and the rotary valve. Hot combustion gases exit tangentially from the secondary combustion chamber into outlet pipe 10 to be passed to the register air dilution means 12 where they are cooled by dilution with ambient air before the gases enter the gas-cleaning equipment. The cooled gases pass from the dilution means into a medium velocity, involute cyclone separator 13' which removes coarse entrained particulate. The separator also provides extended cooling surface for gas temperature reduction. Collected particulate is discharged through a slide valve, not shown in detail in the drawing, into a 55 gallon receiving drum 14. The slide valve permits continuous operation of the gas cleaning system while receiving drums are being changed. A hydraulic jack, not shown in the drawing, maintains a tight air seal between the drum rim and the separator bottom. Screw jacks, not shown in the drawing, are employed as a safety measure in the event of hydraulic failure. Effluent from the separator enters an electrostatic precipitator 15 for removal of fine solid particles, soot, mineral dust, and tar droplets formed by condensation of volatile organic vapors. The precipitator is designed to apply a high negative charge to the gas borne particles and collect the charged particles on grounded metal plates. The particles are charged by rows of vertical wires mounted in parallel frames, not shown in the drawing, 4 inches apart. The frames are connected to the negative terminal of a variable 30,000 volt DC power supply, and the wires are cleaned by vibrators, not shown in the drawing, connected to the frames through nonconductive shafts, not shown in the drawing. Dust shaken from the wires falls into a hopper below. The grounded collector plates, not shown in the drawing, are parallel to the rows of wires in an alternate array and are cleaned by a rapper mechanism not shown in the drawing which lightly raps the bottom plate support to release the dust particles which fall into the hopper. Gas flow is parallel to the wire frames and collector plates. The collected dust is discharged through a slide valve, not shown in the drawing, into a 55 gallon receiving drum 16 beneath the hopper; the slide valve allowing continuous operation of the precipitator while the drums are being changed. As with the separator, a

hydraulic jack, not shown in the drawing, maintains a tight air seal between the drum rim and the hopper bottom while screw jacks, not shown in the drawing, are employed as a safety measure. The precipitator is cleaned only when the remainder of the facility is inoperative; otherwise dust would be carried into the filter bank. Gas leaving the precipitator enters a filter bank 18 of two high efficiency mineral fiber filters. The filter unit is designed to collect particulate blow-off from the precipitator and to provide limited emergency protection in the event of electrical power failure or precipitator malfunction. The unit accepts filter sizes of 24 inches by 24 inches and up to 12 inches deep. After filtration, the gases are exhausted to the stack by means of exhaust fan 19. Four in-line sampling points 17 are located between the air dilution means outlet and the separator inlet, between the separator outlet and the precipitator inlet, between the precipitator outlet and the filter inlet, and between the filter outlet and the exhaust fan inlet.

FIGURE 2 is a schematic diagram of my fluid turbulator 21 invention, and all structures therein described in FIGURES 3 and 4 below. Fluid turbulator 21 replaces register 12 in FIGURE 1. As stated above, this new and improved fluid turbulator dilution system was developed to replace the rotating sleeve dilution valve register due to the poor fabrication, excessive leakage, and unsatisfactory operational control of the prior art incinerator air dilution means.

FIGURES 3, 4, and 5 disclose the fluid turbulator which consists of an 8 inch inlet duct 29 containing an orifice plate 30 and butterfly valve 31 followed by an air mixing chamber 23 with an attached air transition section 26 flanged (by flange 27) to the 8 inch inlet duct 29. The butterfly valve and orifice plate are used to control and measure dilution air rates. Dilution air is drawn into the system due to negative pressure created by the exhauster 19 and enters the mixing chamber where it combines with the hot incinerator eflluent. The mixing chamber is fabricated from mild steel, is totally enclosed to eliminate leakage, is cylindrical, and is approximately 15 inches long and 15 inches in diameter. The transition section which tangentially joins the mixing chamber is horizontally bisected by a curved baffle plate 28 to divide the flow of dilution air entering the section into two streams; an upper and 'a lower. The upper air stream enters the top of the mixing chamber tangentially and follows the contour of the outer wall; thus surrounding the hot gases leaving the incinerator and entering the mixing chamber by means of refractory lined incinerator flue 22. The

curvature of the baflle plate forces the lower air stream to spiral directly into the hot gas stream. The action of the two streams has a combined elfect of a spiral mixing .4 of the hot flue gas and cool dilution air which results in a uniformly mixed gas stream at a temperature within the design limits of the cyclone separator, to which the mixed cooled gas stream is transmitted by means of duct 24. Deflection plate 25 is utilized to create the upper and lower air streams.

It is obvious that other modifications can be made of my invention, and I desire -my invention to be limited only by the scope of the appended claims.

I claim:

1. An improved combustible radioactive waste incinerator system having a combustion chamber means, a flue outlet pipe leading from the combustion chamber means, and an air control means adapted to control the rate of dilution air drawn into said flue outlet pipe, the improvement in said air control means comprising a horizontal air inlet duct and a mixing chamber means interposed in said flue outlet pipe and receiving air from said horizontal duct, curved bafile means extending into said mixing chamber and having an upstream portion bisecting said horizontal duct in a horizontal plane, a lower baflie member at the forward portion of said inlet duct and cooperating with said upstream portion to form upper and lower air streams, the upper of which enters and rotates peripherally of the mixing chamber and the lower of which enters centrally of the mixing chamber.

2. An air control means for an improved combustible radioactive waste incinerator system comprising a horizontal air inlet duct and a mixing chamber means interposed in a flue outlet pipe and receiving air from said horizontal duct, curved baflie means extending into said mixing chamber and having an upstream portion bisecting said horizontal duct in a horizontal plane, a lower baflie member at the forward portion of said inlet duct and cooperating with said upstream portion to form upper and lower air streams, the upper of which enters and rotates peripherally of the mixing chamber and the lower of which enters centrally of the mixing chamber.

References Cited UNITED STATES PATENTS 3,248,178 4/ 1966 Hoskinson. 469,620 2/ 1892 Williams. 3,219,418 11/1965 Whitmire. 3,320,906 5/ 1967 Domahidy. 3,355,254 11/1967 Hoskinson.

JAMES W. WESTHAVER, Primary Examiner US. Cl. X.-R. 1 10-160