US2181789A - Apparatus for the carbonization of material, such as briquettes - Google Patents

Description

E. c. ME NGEL 2,181,789

APPARATUS FOR THE CARBONI'ZATION OF MATERIAL, SUCH AS BRIQUETTES Nov. 28. 1939.

Filed May 11, 1938 f In var/tor /fzftor'nezys Patented Nov. 28, 1939 UNITED STATES TENT OFFICE APPARATUS FOR THE CARBONIZATION OF MATERIAL, SUCH AS BRIQUETTES Application May 11, 1938, Serial No. 207,384 In Great Britain October 4, 1937 11 Claims.

This invention relates to improvements in methods and apparatuses for carbonizing fuel, having reference to those of the general character disclosed or exemplified for instance in the U. S. patent to Smith et al., No. 2,113,520 dated April 5, 193.8.

The object hereof isto provide a carbonizing plant of the kind in which carbonaceous materials (more especially briquettes) are carbonized in a chamberthrough which the materials descend-by the circulation through said chamber .of heated gases, wherein the heating by circulated gases can be maintained for long periods of time without cessation being necessitated for instance by the intermittent charging and discharging of the material .or by accumulation of distillation products in parts of the plant.

Intermittent charging and .discharging of pertions (batches) of materials to be carbonized, whichof course is common toplants of this-kind; is found .to be more than ordinarily important and to require a special consideration in thecaseof materials that soften during carbonization, for the reason that disturbance of the-materials before they have reached a certain .stage of care bonizing, and particularly if weighted by. superimposed .material, brings about deterioration and probable deformation..,or breakage of the lumps or briquette compositions in which-they are formed. On the other hand, after the lumps or briquettes have reached a certain stage of. car bonizing, they become sufiiciently hard and strong to withstand the effect .of even fairly rapid descent in the-carbonizing chamber .and the weight of added fresh fuel.

Also, to obtain economic rates .of production, it is desirable that. .the process of .carbonization shall be continuous .and, consequently, that the circulation of gas through the .material shall .be substantially uninterrupted, .or at least .shall not be interrupted for any substantial period.

In carbonizing material, and more especially coal briquettes, according to the .present invention, batches of the material (hereinafter referred to as briquettes) are charged into the carbonizing chamber preferably a vertical retort stack or Well member through a closed charging vessel fitted at its top and provided with inlet and 'outlet valves suitably interlocked so that they (said valves) cannot bothbe open at the same time and so that the passage of circulating gases need not be stopped when a new batch of briquettes is being introduced into the carbonizing chamber.

The carbonized briquettes are on the other hand discharged at and from the bottom of the chamber in batches so as to make room thereinabove for succeeding batches of fresh briquettes. Each discharging batch is dropped into a rest or receiving chamber beneath the carbonizing chamber by the operation of suitable valves, which valves need not be gas-tight if the bottom outlet from the carbonizing chamber is watersealed, or closed by other suitable means adapted to prevent leakage of gas to the atmosphere and thus tov obviate interruption in the circulation of gas when removing the batches of carbonized briquettes.

The time occupied in discharging successive batches should be as short as possible, since it isdesirable that the period during which the carbonizing chamber is not filled .to the correct level shall be short. Provision of the rest chamber enables a rapid rate of discharge to be attained without the necessity of providing a high capacity conveyor or other means of transport for removing the carbonized briquettes to thepoint of screening or storage. The discharged and carbonized briquettes are slowly discharged from the rest chamber (through the water sealin one arrangement) by means of or onto a conveyor belt operating at economical speed, said rest chamber providing temporary accommodation for the briquettes soas to permit a difference in the rates of discharge from the carbonizing chamber and the removal (by said conveyor) to the point of storage.

When carbonizing briquettes containing pitch or similar-binding materials, the practically uninterrupted circu ation .of carbonizing gas ismade possible by control of temperatures throughout the circuit so as to ensure the removal at suitable points or positions of those constituents that would be likely to accumulate and stop the flow of gas.

For example, in the case of circulating gases ladenwhen leaving the carbonizing chamber with a mixture of suspended carbonaceous dust With pitch and tarry vapors, the dust is first removed .or substantially removed by means of a-bafile box or dust catcher situated in that portion of the off-take pipe where the temperature is such that pitch does not collect, so that the dust is caught and preserved in a dryformreadily removable by hand at infrequent-intervalssuch as once per daywitho.ut stopping the gas circulation for more than amatter of minutes; thereafter, 1. e. subsequently in the system, the temperature is reduced, preferably gradually and not too rapidly, by cooling (as by air) the offtake pipe sufficiently to cause condensation of the heaviest pitch and tarry constituents, but.

not below their melting point, thus ensuring that they flow by gravity into a, suitably dispose-d vessel or seal pot, which may contain a solvent oil, and from which deposits or accumulations can be removed at conveniently infrequent intervals and, with the arrangement shown in the accompanying drawing, without interruption of the;

circulation of gas. I g I The circulating gas, free from dust and heavy pitch constituents, passes through a condenser or condensers, later referredto as primary and secondary condensers, where the temperature is reduced still further by controlled supplies of cooling water and in which oily constituents are thrown off or dropped down and removed continuously through suitable drains without stopping the fiow of gas.

After leaving the condenser or condensers, the gas passes through a cyclone separator adapted to remove still more of the tars or oily constituents, which otherwise would be carried forward in the form of fog or,tarry vapor. der that the temperature of the gas passing through the cyclone separator shall not be adversely affected by variations in atmospheric temperature, it can be controlled by lagging the cyclone separator and/or by providing means for heating it at will with steam.

Having thus removed as far as possible the suspended impurities in the gas, the removal of virtually the whole of the remaining fog is effected by centrifugal separation in the gas circulating fans, the temperature of which, and of the pipe connection thereto, is so controlled that the gas temperature is maintained just conveniently above the solidification point of the tar in order that the separated tar may be flung from the fan blades and drained off from the fan casing without interruption. As an example, one kind of tar requires the temperature of the gas entering the fan to be controlled betweenthe limits of F. and 210 E; if the temperature is lower than 170 F., the flinging of the tar from the impellers is incomplete and a deposit gradually accumulates on the impellers, restricting and ultimately stopping gas circulation, and, if the gas temperature exceeds 210 F., the precipitation of the tar fog by centrifuging becomes less and less complete and an undesirable proportion of residual vapor remains in the gas leaving the fans.

By controlling the gas temperature in the circuit it is possible to operate substantially without any other interruption of the gas circulation than that described required for the removal of solid matter.

Surplus gas is discharged from the circuit when any desired pressure has been reached, through a pressure relief valve, and, to prevent deposition on the working surfaces of the valve which might interfere with its action, all surplus gas, before reaching it, passes through a scrubber placed at the outlet from the circuit, the scrubbing being effected by creosote or other suitable solvent oils; this also prevents deposits in the gas mains, balancing holder and beyond.

A return main from the balancing holder to the circuit on the inlet side of the circulating fan includes a liquid seal (preferably of creosote or other oil) so proportioned that gas can pass from the balancing holder to the circuit when the pressure in the circuit falls, but cannot pass therethrough in the reverse direction.

Automatic means are provided for operating In orthe various valves controlling the flow of gas in the circuit and such means may be hydraulic or mechanical or electrical.

The valves controlling the charging of the fresh briquettes and the discharging of the carbonized briquettes may be similarly operated, although in such case it would probably preferably be done by a separate machine or machines since the charging, discharging and gas circulation cycles may be so widely diiferent.

Although the present invention is intended primarily to be used in conjunction with the invention forming the subject of the aforesaid Letters Patent to Smith et al., No. 2,113,520, or to systems'of the general character therein disclosed, it is to be understood that it is not so limited nor meant to be confined to such particular use, as many of its features are applicable to other processes and other apparatuses for carbonizing material by the circulation of heated gases.

The accompanying drawing illustrates diagrammatically, and by way of example merely, apparatus of the kind referred to in this application for Letters Patent embodying the invention described.

Referring to said drawing, l is the carbonizing and cooling retort chamber or stack, 2 a charging vessel provided with inlet and outlet valves 2 and 2 respectively, adapted to hold a batch of material such as briquettes ready to be introduced into the chamber l; 3 are discharge control doors at the bottom of the chamber I; 4 isa bustle pipe communicating through ports 4 (indicated in dotted lines) with the chamber 1 and through a passage 5 with the top of a regenerator. 6; I is a valve controlling the passage 5 and 8 on theoppo site side of the generator is an air inlet valve; 9

is the valved flue stack from the bottom of the regenerator; H! is a valved passage between the bottoms of the chamber I and the regenerator 6, and H is the circulation-gas pipe connected to the passage l0 intermediate the pair of valves Ill therein.

Below the discharge control doors 3 is a rest or receiving chamber 20 of hopper shape, the lower end of which extends into a water chamber 2! and across the mouth of which there works an inclined slow-running conveyor 22, the arrangement being such that a batch of so-called (and relatively) cooled carbonized material can be quickly discharged into the rest chamber, whence the batch of material is thereafter gradually delivered by said conveyor 22 to a belt conveyor 23 which removes the material to storage.

' of which the heavy dry dust collects and through which any pitch and tarry vapours pass with the gas (still at high temperature) into the cooled (i. e. relatively) downward extension 24 of the pipe 24, which terminates, in the illustrated arrangement, in a seal pot or box 26 where condensed heaviest pitch and tarry constituents, together with any especially fine dust, are trapped. Above the seal pct 26 a branch 2! from the pipe 24 leads to cqndenser unit in this instance comprising connected primary and secondary condensers 28 and 29 respectively, where the partially cleaned gas is further cooled andoily constituents dropped down and-drained away.

Connected with the-top of the secondary condenser 29 is a pipe 30 leading therefrom to a cyclone separator 38 for removing suspended tarry fog, said separator being lagged and/or steam jacketed for the purpose of preventing the gas from being adversely affectedor too cooled by atmospheric temperature. From the separator 3! the gas passes through a pipe 32 to the gas circulating fan 33, which delivers into the circulation pipe H. Said pipe 32 and the fan 33 are maintained at such a temperature as will ensure the contained tar in the gas remaining liquid so that it will be flung off the blades of the fan and can be continuously drained from the fan casing.

Below the fan a branch pipe 34 leads from the pipe H to a scrubber 35, the gas outlet pipe 36 from which latter is fitted with a pressure-relief valve 31 through which surplus gas can pass from the circuit to a balancing holder or reservoir 38. Connecting downwardly from the pipe 36 (and from the balancing holder) is a branch pipe 39 extending into a liquid seal 4%], through which gas can pass back to the gas circuit on the inlet side of the fan 33 when the pressure in the circuit falls sufiiciently, or it is desired for any other reason. The surplus gas is or may be taken oif through the main or tap 4! provided just below the balancing holder.

A blower 42 is provided in connection with the top of the regenerator (under control of the valve 8) for supplying air to said regenerator when gas is to be burnt in order to heat the regenerator. Further, an automatic operator or control system 43 is represented with suitable connections to the various valves for the purpose of automatically controlling the flow of gases according to the intended operation of the apparatus. If it is desired to operate the valves 2*, 2 and 3 also automatically, 2. separate automatic operator or control preferably is andin most cases should be employed, as hereinbefore stated.

What I claim is: 1

1. An apparatus for carbonizing fuel material by the circulation therethrough of heated gas, comprising a vertical retort chamber into the top of which charges of the material are introduced in superposition upon each other and from the bottom of which discharges of the material residue are effected, a receiving or rest chamber beneath said bottom into which the discharges of material are received and associated means for conveying such discharged material therefrom to a place of storage, a gas receiving or reservoir chamber for gas produced by the carbonization of material in the retort chamber, an outlet gas conduit connection between the top section of said retort chamber and said gas receiving chamber, an inlet or return gas conduit connection between said gas receiving chamber and the bottom section of said retort chamber, said inlet or return gas conduit connection constituting in part a portion of said outlet conduit connection and said two connections together with the retort and gas receiving chambers providing a gas circuit or circulatory system, forcecirculation means comprising a fan located in the common conduit part of the two named conduit connections of the system, a pressure relief valve in the outlet gas conduit connection located on the discharge side of said force-circulation means and opening only in the one direction controlling delivery or admission into the gas receiving chamber, a liquid seal in the inlet or return gas conduit connection located on the admission side of said force-circulation means and passable only in the one direction permitting return of gas from the gas receiving chamber back into the circuit and into the retort chamber, and a tap or take-off connection in that part of the circuit delivering to said gas receiving chamber for drawing offv gas therefrom.

,An apparatus for carbonizing fuel material according to claim 1, includ ng in advance of the pressure relief valve controlling gas delivery into the gas receiving chamber, a scrubber through which the gas is passed to remove any possible depositive tarry content therein.

3. An apparatus for carbonizing fuel material according to claim 1, including a valve arrangement in the bottom of the reto-rt chamber for permitting the discharge of material therefrom, said valve being controllable by automatic actua ting means.

4. An apparatus for carbonizing fuel material according to claim 1, including means affording control of the temperature of the gas in the whole and parts of the circuit so as to ensure the removal at suitable points therein of those constituents that would be likely to accumulate and stop the flow of gas therethrough.

5. An apparatus for carbonizing fuel material according to claim 1, including a baffle-box or dust catcher so situated in the gas outlet conduit from the carbonizing chamber that dust is trapped therein without any obstruction or retardation of the gas flow and before any reduction of temperature of the gas such that pitch and tarry vapors might be also trapped or deposited in the same.

6. An apparatus for carbonizing fuel material according to claim 1, including a seai pot or box located in the gas outlet conduit from the carbonizing chamber for trapping and collecting heavy condensed pitch and tarry constituents in the gas before it reaches the force-circulation means and is therefrom admitted to the gas receiving chamber or returned to said carbonizing chamber.

7. An apparatus for carbonizing fuel material according to claim 1, including in the gas outlet conduit part of the gas circuit, in advance of the force-circulation means, a condenser wherein the gas is partially cooled and relieved of oily or tarry constituents.

8. An apparatus for carbonizing fuel material according to claim 1, including a cyclone separator in the gas outlet conduit part of the gas circuit for removing suspended tarry fog or vapor from the gas before it reaches the force-circulation means and is therefrom admitted to the gas receiving chamber or returned to the carbonizing chamber.

9. An apparatus for carbonizing fuel material according to claim 1, including a bafile-box or dust catcher, a seal pot or box, a condenser and a cyclone. separator in the gas outlet conduit section of the gas circuit for successively and progressively collecting and removing dust, pitch or tarry constituents, oil or tarry vapors and other foreign matter from the gas before it reaches the force-circulation means and is therefrom admitted to the gas receiving chamber or returned to the carbonizing chamber.

10. An apparatus for carbonizing fuel material according to claim 1, including a bafiie-box or dust catcher so located in the gas outlet from the carbonizing chamber as to trap and collect dust from the gas flowing therethrough before any reduction of temperature thereof sufficient for pitch or tarry vapors to be also trapped or released and deposited therein, and a heavy tar trapping box or seal pot, a condenser and a cyclone separator all located intermediate said baffle-box or dust catcher and the force-circulating means in the outlet part of the gas circuit, said arrangement providing for the gradual and 'eifectual elimination of dust, pitch and tarry vapors or constituent from the gas before it reaches said force-circulating means and is therefrom admitted to the gas receiving chamber or returned to the carbonizing chamber.

11. An apparatus for carbonizing fuel according to claim 1, wherein the pressure relief valve in the gas outlet conduit connection provides for releasing or delivery into the gas receivingchamber only surplus or excess pressure gas not desired in the remaining part of the gas cir cuit for continued cycle operation.

ERIC CHRISTIAN MENGEL.

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