US1941130A - Coal distillation and coke produc - Google Patents

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Dec. 26, WEEKS AL COAL DISTILLATION AND COKE PRODUCTION PLANT Filed March 13. 1930 4 heets-Sheet l C 1933- E. G. WEEKS ET AL COAL DISTILLATION AND COKE PRODUCTIQN PLANT Filed March 13. 1930 4 Sheets-Sheet 2 4 Sheets-Sheet 3 Dec. 26, 1933. E, GJWEEKS ET AL COAL DISTILLATION AND COKE FRODUCTION PLANT Filed March 13, 1930 M G m M.

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1366- 26, 1933- E. G. WEEKS El AL COAL DISTILLATION AND COKE PRODUCTION PLANT Filed March 13, 1930 4 eets-Shee 4 Patented Dec. 26,1933

UNITED STATES COAL VDISTILILATION AND COKE rnonuc 'IION PLANT.

EdmundGeorge Weeks, Dunsto'n, Durham,and

WilliamArnold Riley, Low Fell, Durham, Eng- I land, assignors to'Babcock 66 Wilcox Limited, I

London, England, .a British company;

Application March 13, 1930, Serial No. 435,497, and in Great BritainMarch 23', 1929 j 3 Claims. ((31. 202 -262) I This-invention relates tothe distillation vof coal and the; production of coke andhas' for its object to provide an improved and unitary arrangement of coal distillation plant by which the coal is treated from its delivery toa hopper to the discharge of the quenched coke out of contact with air other than that intentionally. supplied.

The improved apparatus comprises a preheater to which the coal is delivered from a hopper, a retort into which the preheater discharges, means for controlling the rate of extraction of the coke in the retort in dependence on the level of the fuel bed, and a coke quenching device in the form of a closed container connected. direct to the lower end of the retortand through whichthe coke is conveyed into and through coke quenching means before delivery to the atmosphere.

,The improved arrangement ofapparatus. is illustrated more or less diagrammatically in Fig.

1 of the accompanying drawings which showthe retort and coke quenching device associated with the coal hopper and the preheater. 'Fig.. 1a is a more or less diagrammatic sectional view showing the coal hopper and preheater; Fig. 2 illustrates, also moreor less diagrammatically, hydraulic driving gear and the means forregulating the rate, of extraction in dependence on the level ,of the fuel bed. Y c Fig. 3 is a diagrammatic representation. ofa simplified form of the means for regulating the rateof extraction in dependence on the level of therfuel bed;

Fig. 4 isasection on line A-A of ,Fig. 6;

Fig.5.is, a section on line BB of Fig, 6; and Fig. 6 is a plan view of the control valve. I o

e o In the drawings, A indicates a hopper'from which coal is fed to a'preheater B where it is dried and preheated and through which it is conveyed on an endless grate A1 over the end-of after described or back tothe hopper A by Way a of anelevator I-I' operating in a conduit Cokeis extracted from the retort 1 by rotary extractor rollers 3 the speed of whichiscontrolled by a float K which contacts with the upper sur- I, face of the fuel bed within the retort 1 atthe end which float on excessive movement-dueto fall mechanism to slow downthe speed-of rotation J remote frorn the charging end thereof and of the extractor rollers 3 and thus reducerthe rate of extraction of coke from the retort 1.;

Assuming that the extraction of coke from the V retortl balances the coal charged in, the conveyor E will move across the retort 1 a ribbon V of coal of constantly diminishing thicknesawhich :is a maximum at the charging end and gradually diminishes-towards the end J. Assuming the extraction of the coal charged in then the surplus as stated above is discharged through the overflow channel ,7

coke less than i 2 and through the sealing valve F eitherto the coke quenching conveyor G or by means of the. elevator back to the ccalhopper A.

Assuming the extraction of coke is greater than the coal charged in, and the retort 1 starved-of coal, the fall in level of the fuel bed therein=will be first apparent at the end J. I p .This'drop in level of the fuel bed is taken advantage ,of by the present invention to regulate 'the' speed of the coke extractor rollers 3. ,The

float K has a minimum reciprocating motion to negotiate the coal levelling scraper bars of the conveyor E and is disposed between the upper and "lower flights of the conveyor E so that, as the The control gear for controlling the speed of the extractor; rollers 3 in accordance with a feature of the invention is illustrated in Fig. 2. Re-

ferring to that figure, L, L1, Lzindicate hydraulic cylinders adapted through levers M, M1, M2,

pawls N, N1, N2, and ratchet wheelsO, 0;, O2, to

drivethe extractor rollers3. The supply of pressure water is controlled by a master hydraulic valve P-which is driven by an engine Rwhich may be hydraulic or electric. v The float K, is given 'a reciprocating motion by'means of a cam Sand levers Tand V. The cam S is timed to lift the float K every timea scraper bar E passes, the 7 down stroke of the float K being limited by'the level of the fuel bed. Should this level fall the stroke of the float K is increased.

angle is increasedbythe angle 0 when the fuel bed lowers. With the lever V is associated a lever W which is arrangedto contact with a-push o 7 Under normal conditions, with a level fuel bed, the lever V moves through an angle up but this rod X which in turn is connected to the piston of a dash pot cylinder Y. This dash pot cylinder Y is fitted with a charging valve a, a leak-ofi needle valve b, and return spring 0. The piston of the dash pot cylinder Y is also operatively connected to a regulator Z for the engine R.

The action of the control gear is as follows: During normal operation when the fuel bed is level, the float K and lever V have a movement corresponding to the angle and the lever W does not operate the push rod X; but should the fuel level fall the stroke of the lever W is increased and it depresses the push rod X. This push rod being connected to the regulator Z retards the speed of the engine R and so reduces the speed of the extractor rollers 3 with consequent reduction in the quantity of coke extracted.

On the downward movement of the push rod X the dash pot piston draws in water though the charging valve a. Under the action of the return spring c the water-escapes through the needle -valve b and the piston and push rod return slow- 1y to their normal positions. The mean position of the-piston and therefore the corresponding position of the regulator Z is determined by the level of the float K. The dash pot cylinder Y and piston and return spring 0, charging valve a, and

needle b are provided to return the regulator Z to its normal position as the fuel bed returns to its correct level.

Iii-Fig. 3 which shows the control gear for controlling the speed of the extractor rollers in which the float K of Fig. 2 takes the form of a level plate and in which the cam S and the other members shown in Fig. 2 are omitted, the rod X operated by the float by means of a rack X1 actuates a rheostat Z which controls the speed of the engine. In this instance it is a D. 0. motor R which drives through a reduction gear R1 a control valve P controlling the supply to the hydraulic cylinders L, L1,- L2, etc. When the level of the fuel bed falls, the rheostat is operated by the rack X1 in such a manner as to reduce the speed of the motor R and consequently to reduce the speed of operation of the control valve P, so that the rate of displacement of the pistons in the cylinders'L, L1, L2, etc. and therefore the rate of extraction of the coke by the extraction rollers is reduced. On the rise of the fuel-bed level the rod X is operated to actuate the rheostat in such a manner as to increase the speed of the motor R and hence to increase the speed of rotation of the control valve P and to increase the rate of extraction by the extraction rollers.

As shown in Figs. 4 to 6, this control valve consists of a valve chest 20 including a cam shaft 30 driven through thereduction gear R1 of Fig. 3 by the motor R in that figure, the cam shaft in turn operating the supply to and from the connection leading to the cylinders L, L1, L2, etc.

Beneath the retort 1 and connected therewith by automatic rotary coke discharge and retort sealing valves B1, B2, is coke quenching means comprising aclosed casing C1 containing the scraping conveyor G fitted with scraper bars G1. The upper run of the conveyor G is carried on a horizontal partition P which ensures that the incoming coke is conveyed in the direction of the arrow G2 into a quenching bath G3 in which a predetermined level of water is automatically maintained. The use of the bath G3 filled with I water to the proper level has the advantage that obtained once the correct water level has been determined for any given working conditions. It

will be readily appreciated that the use of sprays alone to cool the coke necessitates constant adjustment of the water to ensure that the ratio of water to coke is correctly maintained which is a difficult matter to arrange in practice, whereas by the use of a sump or bath of water the degree of quenching is automatically controlled as each particle of coke is passed through a cooling zone of constant length. The scraper bars G1 of the-conveyor G drag the coke through the Water as the result of which steam is generated and the coke efiiciently cooled so as to prevent any danger of subsequent ignition on exposure to air. Jets F1 and F2. for spraying water on the coke maybe provided above the conveyor G as an auxiliary cooling means. After passing through the quenching bath G3 the coke is conveyed by the scraper bars G1 in the direction of the arrow J1 to the discharge end of the conveyor G where it is delivered through a continuous rotary sealing valve K1 which discharges into bunkers-or trucks for storing or conveying the cooled cokeas desired.

The combustible gas from the coke in admixture'with the steam generated from the cooling of the coke is conveyed by the duct- 4 to the retort combustion chamber D1 where it is used to assist in the production of suitable heating gases for the retort. The bulk of the heating gases are generated by the combustion of gas or pulverized fuel in the burner M4.

The pressure of the mixture of steam and gas in the conveyor casing C1 is the same as in the combustion chamber D1 and is usually below atmospheric pressure by about 2/10 (two tenths) of an inch water gauge.

Under these conditions it is obvious that the temperature of the water bath G3 and the coke leaving the bath must be about 200 F. or higher and if the coke which may contain some moisture were discharged to the atmosphere in this condition it would give on volumes of water vapour. It is therefore desirable that before discharge the coke should be partially cooled by contact with air, and for this purpose air in regulat'able quantities or the like is admitted for example by way of the adjustable damper N1 which air passes through the conveyor casing C1 and absorbs water vapour and enters the combustion chamber D1 along with the steam and combustible gases livery of the coal to the hopper A to the discharge of the quenched coke out of contact with air other than that intentionally supplied.

We claim:

1. In an apparatus for the distillation of coal and the production of coke, a retort comprising a fuel-bed container, .a coke discharge for the retort at the bottom of said fuel-bed container including a coke extractor, means for operating said coke extractor, and means for automatically changing the speed of operationof said coke extractor as the level of the upper surface of solid fuel in said fuel-bed container changes.

2. In an apparatus for the distillation of coal and'the production of coke, a retort comprising a fuel-bed container, means for supplying solid fuel to said fuel-bed container, means for distributing solid fuel in a layer in said fuel-bed container, a coke discharging means for the retort at r the bottom of said fuel-bed container including a coke extractor, means for operating said coke extractor, and means for automatically decreasing the speed of operation of said coke extractor as the level of the upper surface of the solid fuel in said fuel-bed container lowers and for automatically increasing the speed of operation of said coke extractor when said level rises.

3. In an apparatus for the distillation of coal I and the production of coke, a retort comprising a fuel-bed container, a charging hopper for solid.

EDMUND GEORGE WEEKS. WILLIAM ARNOLD RILEY.

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