US2066704A - Production of coke and gas in chamber ovens - Google Patents

Description

Jan. 5, 1937. c. STILL, 2,065,704

I PRODUCTION OF COKE AND GAS IN CHAMBER OVENS Filed May' 12, 1951 2 Sheets-Sheet 1 Jan. 5, 1937. i c. STILL V Q 2,066,704

PRODUCTION OF COKE AND GAS IN CHAMBER OVENS Filed May 12, 1931 2 Sheets-Sheet '2 v Patented Jan. 5,

.these difierences, relatively to the difierences of UNITED STATES PATENT OFFICE PRODUCTION OF COKE AND GAS IN Q CHAMBER OVENS Carl Still, Recklinghausen, Germany Application May 12, 1931, Serial No. 536,850

, In Germany May 19, 1930 2 Claims. (01. 202-30) ,which is generally above the charge of coal, and

if, as is usual, a definite constant pressure is to be maintained in this space by controlling the suction, which pressure is generally adjusted to mm. of the water gauge relatively to the atmospheric pressure, it is sufficient to maintain this definite suction pressure in the said space itself. If, on the other hand, the, distillation gases are to be drawn off from the interior of the charge of coal, 1. e. by ducts disposed within the charge of coal and provided with devices for leading away to the exterior the gases and vapours, the suction pressure prevailing in these ducts must be adjusted in such a manner that the required constant pressure, relatively to the external atmospheric pressure, is maintained in the gas space which. exists above the charge of coal and is independent from the said internal spaces. In this case the problem of the regulation or controlling consists essentially in the fact that" the ducts in which the suction pres sure is to be controlled (viz. the interior of the coal) are other than that space above the charge in which the constant suction pressure is to be maintained.

Essential features'of the invention consist in the facts that there should be a difierence of pressure between these two spaces during the greater part of the working of a charge, and that pressure usually employed in drawing ed the gases and vapours, are very great and also vary to a great extent. While, in the usual suction process pressure differences within the oven of at most a few mm. of the water gauge have to be allowed for, there are on the contrary, when suction is to be applied to the internal ducts,

pressure diflerences between the gas collecting space above the coal and the said ducts which may have many times the above-mentioned values. For example, directly after the com mencement of the carbonizing period the suc* of the water gauge below atmospheric; towards the end oi the carbonizing'period, or towards the end of the time in which the internal suction ceases, the pressure may exceed 150 or 200 mm. of the water gauge below atmospheric.

Since also,; and this in practice is usuallythe case, a large number of oven chambers or retorts is connected into a battery, and since, in the usual method of working, a large number of adjacent chambers is at different stages of 10 working, and the gases to be drawn ofi from the interior of the charge must be led ultimately into a gas collecting pipe or hydraulic inain common to the whole battery, a further feature of the invention consists in adjusting the suction pressure in the interior of each individual oven, independently of that maintained in all the other ovens, to the value required in each individual stage of the working; that is, it must be varied in the course of time. 7 Consequently, as in the said common gas collecting pipe only a definite constant pressure below atmospheric ,canalways ,be maintained by a gas exhauster, this pressure must' necessarily represent a vacuum which is lower than the lowest pressure present at any time in the interior of any individual oven.

, The accompanying drawings represent an embodiment of the invention as applied to a. horizontal coke oven battery.

Fig. 1 is a vertical longitudinal section through the centre of a .coke oven chamber, showing only a portion of the length and heightof the chamber, and

'Fig. 2 is a vertical central section. on a ler scale, of the special apparatus for controlling the pressure.

Fig. 1 shows the oven chamber closed on the right by a door I 2 is the oven roof and t the coal charge represented in section; the charge is, in the usual manner, introduced into the 9 chamber through charging openings in the roof 2. There is the usual free gas collecting space d above the coal charge 3 and below the arch of the roof 2. The distillation gases and vapours are drawn ad from the interior of the charge 345 by ducts 5 and tubes 5 inserted gas-tight in openings l of the roof 2. The openings are closed from above by covers 8. A large number of the devices 5, t, and i is providedin a central row over the whole length of the ovemchamber. The openings l are connected by lateral tubulures 91 with a pipe It inserted in the roof 2 and extending over the whole length of the chamber. The pipe it projects at the front end of the oven and carries at that place a vertical branch pipe II. The latter is connected through a by-pass junction I2 with the cover 13 of a pressure controlling apparatus l4 which is described later.

The distillation gases and vapours entering the apparatus l4 are led through outlet connections l5 and I3 and pass into the gas collecting pipe or hydraulic main II common to the whole oven battery. As shown in Fig. 1, the device I4 is inserted in the path of the distillation gases between the pipes and I1. A pipe 18, of which one end l9 opens in the arch of the oven roof 2 and the other end 20 communicates with the apparatus l4, connects the latter with the gas collecting space 4 of the oven chamber, in which the pressure is to be maintained at a definite constant value. I

The construction of the gas controlling apparatus I4 is shown in detail in Fig. 2. The upper part of the apparatus l4 forms a liquid container 22 closed by a base plate 2|. A junction piece 23 forming a continuation of the by-pass l2, projects downwards from the cover l3 and carries several vertical tubes 24 of which the lower ends are immersed in the liquid of the container 22. The depth of immersion is determined by the diiference of level between the uppersurface 25 of the liquid and the lower edges 26 of the tubes 24. The container 22 receives a constant flow of fresh liquid through a lateral tubulure 21 from a water pipe 28 (Fig. 1) common to all the individual devices H of the oven battery. Another liquid container 29 is disposed below the base plate 2|; in the container a float 30, in the form of a diving hell, can move vertically, and for this purpose'is guided above and below by a central spindle 3|, as shown in Fig. 2. The air space of the float 33 communicates with the external atmosphere by a pipe 48 inserted through the bottom of the container 29. The spindle 3| of the float 33 carries at its upper end a conical valve 32 which can seat itself on a seating 33 disposed in the base plate 2|. A stationary dome-shaped guard 34 is arranged between the float 30 and the valve 32. The pipe I8 is connected by the tubulure 20 with the gas space above the float 33 and at its other end 19 with the space 4 above the charge 3 in the oven chamber. a

The bottom of the container 29 is connected by a pipe 36 and a three-way cook 31' with an overflow vessel 38 inserted in a chamber 39. The cone-shaped vessel 39' can be screw-threaded in the vertical direction on the hollow stem 40 projecting from below into the casing 39, in order to adjust the height of the overflow surface and consequently the level 01' the liquid in the vessel 29 and the position of equilibrium of the float 30.'

The cover, 4| of the casing 39 has an opening 42 for the discharge of air in order that there should always be atmospheric pressure in the overflow vessel. The liquid is discharged from the casing 39 through a connection 43 and a pipe 44 connected to it, to which a branch pipe 45 is attached. The pipe 44 is connected through the three-way cock 31 to a pipe 46 (Fig. 1) common to the oven battery. .The three-way cook 31 in the position shown in Fig. 2 connects the container 29 with the vessel 38. If the three-way cook 31 is rotated towards the left through by the lever 41 (Fig. 1), the container 29 and -with it the vessel 38 and the chamber 39 are brought into direct connection with the discharge The action of the apparatus represented in Figs. 1 and 2 is as follows:--

It is assumed that in the gas collecting space 4 of the oven chamber, a pressure is to be maintained constantly at the value of 0 mm. of the water gauge or at a value which does not differ in either direction by more than a very small amount from this value, and it is also assumed that, in the particular working stage in consideration, a suction pressure of mm. of the water gauge below the atmospheric pressure for drawing off the gases, must be maintained in the ducts 5 in order to comply with the condition that in the gas collecting space 4 the pressure should be 0 mm. Besides, it is assumed that a constant pressure of 250 mm. of the water gauge below atmospheric is obtained in the gas collecting pipe l1, common to the oven battery, by a gas exhauster (not shown) of the installation which, obviously, must be correspondingly regulatedseparately. From the preceding terms it is seen that, if no other resistances to the flow of the gases exist, a resistance absorbing "pressure of 250-110:140 mm. of the water gauge must be inserted between the pipes l0 and 11 in order to comply with the above pressure conditions.

This pressure absorbing resistance is, according to the invention, produced by the immersion of the tubes 24 in the liquid of the container 22. The difierence' of level between the upper surface 25 of the liquid and the lower surface 23 of the tubes 24 must, since water is the sealing liquid, be equal to 140 mm. When this condition is obtained, in order that it should be' maintained unaltered, the water must be discharged at the base 2| through the valve 32, 33 at a rate corresponding accurately to the inflow of water through the connection 21. This obviously is only possible at a certain exactly definite vertical position of the float 30. This vertical position again is afieoted by the value of the pressure acting on the upper surface of the float and this pressure is practically the same as that present in the gas collecting space 4 of the oven chamber.

In order to consider now a somewhat modified stage in the further progress of the working, it may be assumed that the gas suction pressure of 110 mm. of the water gauge below atmospheric is no longer suflioient in the ducts 5, for instance since, due to the increased resistance met with by the gases flowing through the mass of coal, the pressure in the space 4 of the oven chamber obtaining above the charge of coal 3 increases, the new amount being 0+0: mm. of the water auge.

, This increased gas pressure is transmitted through the pipes l9 and I3 and the connection 20 into the gas space above the liquid in the container 29; it lowers to some extent the level of the liquid 29 and produces also an additional load on the float 30 proportional to the pressure difference 2:. This additional load depresses the float 30, opens somewhat further the valve 32 and thereby temporarily increases the outflow of water from the container 22. Since, however, the flow of fresh water through the connection 21 is unaltered, the depth of immersion of the tubes 24 is reduced. Thereby the pressure absorbing resistance inserted between the collecting pipes l 0 and I1, due to the immersion of the pipes 24, is reduced, with the result that the eifective suction in the ducts 5 of the coal charge 3 is increased, for example to the amount required at that time of mm. of the water gauge below the atmos- 15 pheric. In this way, the normal equilibrium is again obtained, that is in the gas collecting space 4 of the oven instead of the temporary pressure 0+3, the normal pressure 0 mm. is again obtained. This latter pressure istransmitted through the pipes l9, l8 to the float 30 and allows the latter and the valve 32'to return again into their former higher position in which the discharge from the container flow through the connection 21. Consequently, the reduced depth of immersion obtained by the previous automatic regulation is permanently established, that is, the apparatus is again in equilibrium and its normal working condition.

The control apparatus acts in a corresponding manner, if the suction in the ducts 5 is reduced instead of, as previously assumed, being increased. In this case the pressure obtaining in the gas collecting space 4 reduced to an amount 0-3: by which the load on the container 29 of the apparatus I4 is also reduced, and thereby the float 30 is temporarily raised, obstructs the outflow of the liquid from the container 22 and consequently increases of the tubes 24. The controlling device, consequently, corresponds to any departure in thegas collecting space 4 from the gas pressure selected as the normal value, so as to change the depth of immersion of the tubes 24 until the normal condition has again been obtained in the gas collecting space 4.

The suction control according to the invention is not restricted to'the use of' the control apparatus described. Any regulating devices may be employed which are usual if they solve the problem of regulation according to the invention. Also, it is not necessary that the resistance absorbing the pressure should be produced by a column of liquid. Throttling devices of any suitable kind can be employed at these positions. The regulation might be efiected manually instead of automatically.

In the example illustrated in the drawings, as

- shown in Fig. l, the case was assumed in which the gaseous products of distillation were only drawn ofl from the ducts 5 of the coal charge; but the use of the invention is not restricted in this respect. Nothing would be altered in the problem and its solution, if the gases were drawn off partly by suction from the inner spaces 5 as described and partly also from the gas collecting space 4 of the oven chamber, as in the usual manner, by means of an ascension pipe into an hydraulic main specially provided for this purpose and also maintained at a definite pressure, for example 3 mm. water gauge below atmospheric. For example, gases are drawn of! from the internal spaces 5 through the tubes 6 only during the first part 22 is equal to the inthe depth of immersion for similar purposes,

the case may arise in which the of the carbcnizing period of a charge, and where no internal suction during the second part of the carbonizing period exists, so that, during this second stage, suction is provided in'the usual manner from the gas collecting space 4. Also, the further casecan be considered in which, at least during a definite period of carbonizing, the gases are drawn ofi simultaneously from the ducts 5 and also from the gas collecting space 4. In all these cases the suction, as long as it is effective in the interior of the charge, must be controlled according to the invention so that the gas pressure in the gas collecting space 4 is maintained at the value determined from practical considerations, generally at 0 mm.

What I claim is:- I

1. The process of withdrawing volatile distillation products from the interior of a charge of coal in an externally heated chamber oven for the production of coke and gas and wherein a gas collecting space is arranged above the coal charge; which comprises the steps of initially maintaining said/ gas collecting space above the charge at atmospheric pressure, automatically maintaining this pressure in the gas collecting space above the charge substantially constant throughout the period of distillation, withdrawing volatile distillation products from only the interior of the charge by suction below atmospheric pressure, and automatically varying the suction within the interior of. said charge by the change of said pressure in said gas collecting space to increase the suction within the interior of the charge as the pressure inthe gas collecting space increases and vice versa to diminish the suction within the interior of the charge as the pressure decreases in the gas collecting space.

2. The process of withdrawing-volatile distil from only the interior of eachv charge-by suction below atmospheric pressure, and automatically varying the suction within the interior of each charge independently of the other charges and by the change of pressure in the gas collecting space above said charge to increase the suction within the interior of each charge as the pressure inits gas collecting space increases and vice versa to diminish the suction within the interior ofeach charge 'as the pressure decreases in said gas collecting space.

CARL STILL.

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