US1790823A

US1790823A - Apparatus for manufacture of combustible gas

Info

Publication number: US1790823A
Authority: US
Publication date: 1931-02-03
Anticipated expiration: 1948-02-03

Description

5 Sheets-Sheet 1 FH'I I H. o. LOEBELL APPARATUS FOR MANUFACTURE OF COMBUSTIBLE GAS Filed Sept 21, 192.5

Feb. 3, 1931.

wwwtoz @MM a QZ flmm Feb 3, 193%. H. o. LOEBELL 1,790,823

APPARATUS FOR MANUFACTURE OF COMBUSTIBLE GAS Filed Sept. 21, v1,925 3 Sheets-Sheet 2 Feb. 3, 1931. H. o. LOEBELL APPARATUS FOR MANUFACTURE OF COMBUSTIBLE' GAS Filed Sept. 21, 1925 5 Sheets-Sheet 5 Patented Feb. 3, 1931 UNITED STATES PATENT OFFICE HENRY o. Lorentz, or NEW 1031:, 1w. Y., assrexoa r nann L. nonanr'z, on NEW YORK, N. Y.

APPARATUS FOR MANUFACTURE OF COMBUSTIBLE GAS Application filed September 21, 1923. Serial No. 668,993.

This invention relates to the manufacture of combustible gas and more particularly to apparatus for making water gas. v

The present invention has a particular re- 5 lation to the intermittent method of making Water gas by which a high temperature is maintained in'adefinite portion of the fuel bed by intermittently blasting air therethrough and then treating with steam .to

make gas, the fuel being continuously assed through the high temperature zone. 11 the patent to Henry L. Doherty, 1.426,159, issued August 15, 1922, is shown and described an intermittent method of making water gas by 15 which the heat of combustion and the sensible heat of the blast exhaust gases are recovered in heat regenerators, and the sensible heat of the combustible gas being made is absorbed in the fuel being carbonized and preheated.

In the Doherty method the fuel is passed through the generator faster than it is burned to prevent the formation of clinkers, and coke discharged from the generator is cooled by steam introduced into the generator for gas making.

The present invention is the improved apparatus for the manufacture of combustib gas to be used particularly in conjunction with the method of manufacture of combustible gas described in my co-pending divisional application, Serial No. 481,195, filed June 29, 1921.

For generators having a comparatively small cross sectional area at the high temperature blast zone, the Doherty method of making gas will give very high thermal efiiciencies and an excellent heat balance; It has been found, however, that when using a generator having a large cross sectional area, to provide a large gas making capacity, the blast exhaust gases contain too much potential heating value to give the proper heat balance. This is due to the fact that the passage of air through a deep fuel bed will form a hi h percentage of carbon monoxide. At the time the air blast first enters the fuel bed, carbon dioxide is formed and then as the carbon dioxide passes through the fuel bed it is reduced to carbon monoxide. If exhaust gases contain: ing carbon monoxide are burned in a regenerator, theheat of combustion and the sensible heat of the exhaust gases will provide a much larger volume of heat than is necessary to preheat the air for blastin and therefore the exhaust gases must be discharged from the regenerator hot, and deleterious temperatures ma be developed in the regenerator.

-One 0 ject of the present invention is to provide an apparatus for makin water gas by use of which high thermal efliciencies may be maintained in the gas making operation, regardless of the size of the fuel bed being treated.

In accordance with this object, one feature of the invention contemplates storing in a regenerator the sensible heat and the heat of combustion of the exhaust blast gases in such a manner that the heat may be utilized to vaporize water to form steam for use in the gas making operation.

Another feature of the invention contem plates the provision of regenerators for use in con]unction with a gas making enerator by which the heat ofthe exhaust b ast gases may be carried back to the fuel in the enerator by preheating the air used for b asting and by superheating the steam used for gas making.

A further feature of the invention contemplates the control of the temperatures and the position of the storage of the heat in the regenerator by which the air and steam for gas making may be heated to any desired ternperature. i

Operating experience has shown that no particular advantage may be gained in developing very high temperatures (that is temperatures above 27 00 Fahrenheit) in the fuel bed, because the increased rate of formation of gas and the extra volume of gas which may be obtained at the very high temperatures are not large enough to offset the damage caused to the generator linings and trouble caused by the formation of clinkers. Ac-

cordingly, another object of the invention is to provide an apparatus for making water gas by use of which the temperatures inthe fuel bed may be controlled to give a high gas making efiiciency and a large gas making capacity. With this object in view another water gas.

feature of the invention contemplates the circulation of blast air and gas makin steam through the fuel column in such a manner that endothermic reactions will be maintained throughout substantially the entire length of the high temperatm'e zone of a fuel column.

Another object of the invention is to provide an apparatus for making combustible gas by use of which the quality of gas made may be widely varied and accurately controlled.

With these and other objects and features in view. the invention comprises the improved apparatus for making combustible gas hereinafter described, and particularly defined in the claims.

The various features of the invention are illustrated in the accompanying drawings, in which Fig. 1 is a view in the front elevation with parts broken away showing an improved gas making generator, and its accompanying regenerators which embody the preferred form of the invention;

Fig. 2 is a top plan view of the generator and regenerators shown in Fig. l;

Fig. 3 is a vertical sectional view of the generator and one of the regenerators;

Fig. 4 is a horizontal cross sectional view of the generator taken on the line 41 of Fig. 3;

Fig. 5 is a horizontal sectional view of the furnace taken on the line 5-5 of Fig. 3;

Fig. 6 is a transverse sectional view. and Fig. 'i' is a longitudinal sectional view of the hot valves used in the connections between the regenerators and the generator;

Fig. 8 is a vertical elevation showing details of the valves for 'controlling the admission of water to the rcgenerators and to the bottom of the gas generator: and

Fig. 5) is a plan View with parts broken away showing details of the same water control valves.

- The method of making gas with the apparatus which embodies the preferred form of the present invention is particularly adapted for making a gas consisting of a mixture of coal gas and blue water gas. To accomplish this, a mixture of coal and coke in which the coke may vary from one-fourth to one-half the amount of'coal, is passed downwardly in a column through a shaft. the coal being distilled to form coal gas, and therafter the coke admitted and also that formed in carbonizing the coal is treated with steam to make blue The coal gas and the blue water gas which are formed both pass upwardly through the fuel column and are mixed at the time they leave the fuel column. To generate gas from the fuel a high temperature zone is maintained in the mid-portion of the fuel column by blasting air through the high temperaturezon'e. The high temperature zone is comparatively long, and by the time the blast gases have passed through it, they contain :1

comparatively high percentage of carbon monoxide. The exhaust blast gases from the high temperature zone are carried into regenerators where they are burned, and the sensible heat of the gases, together. with their heat of combustion is absorbed in refractory storage elements to be used for preheating the air used in the blasting and for forming steam and superheating steam used in gas making. During the blasting operation the air for blasting is preheated in one regenerator and the blast products are burned in a second regenerator. During the gas making operation water is admitted to both regenerators to form steam, the steam is superheated in the regenerators. and passed into the fuel column at the bottom of the high temperature zone. From the high temperature zone the gas formed together with any excess steam passes upwardly through the fuel column to impart its sensible heat thereto, whereby the coal of the fuel column is carbonized, the coke in the fuel column is preheated, and the gases are cooled substantially to the condensing temperature of steam at the time they leave the fuel column. During the gas making operation water is also applied to the bottom of the fuel colunm to quench the fuel and thereby form steam, and this steam passes upwardly through the fuel column to the high temperature zone, where it joins the steam being admitted through the regenerators to form gas. During both the gas making and blasting operations the fuel moves continuously downwardly through the fuel column.

The preferred apparatus for making gas which is shown in the drawings may be used for carrying out the method described, as follows:

A mixture of coal and coke is placed in a hopper 10, Fig. 3, and passes through a valve 19. into a charging hopper 14. \Vhen the valve 12 is closed, the fuel mixture may be discharged from the hopper 11f through a valve 16 into the top of a gas generator shaft 18. The

valves

12 and 16 are operated intermittently to prevent the escape of gas from the shaft 18. and any fuel or material which may be lodged on the seats of the

valves

12 and 16 may be removed by means of steam admitted through pipes 20 and 22.

The fuel passes downwardly through the shaft, substantially continuouslv and when itreaches arches 24. positioned at opposite sides of the shaft in about its mid-portion, it is subjected to an air blast, the air being admitted through

necks

26 and 28. which are connected with the shaft directly behind the arches 24. J

The air for blasting is circulated by means of a blower 30, Fig. 1, and passes through a conduit 32, into water vaporizing elements 34 of a regenerator 3G or 38. \Vhen air is passing through the regenerator 36. Fig. 3, it enters the top of the vaporizing element 3% .fuel column.

from the conduit 32 and immediately comes in contact with the refractory brick positioned within the vaporizing element. After the air passes through the vaporizing element it flows through a superheating element into a chamber 42. From the chamber 42 the air passes through the neck 26 to enter the The

necks

26 and 28 are interconnected by a conduit'44, Figs. 1, 2 and 4, so that theair is simultaneously introduced into the fuel column behind the arches 24 at both sides of the column. The air entering the fuel column below the arches 24 passes downwardly through the fuel column, and the blast products or exhaust-gases leave the column behind arches 46, Figs. 2, 3, 4 and 5, which are positioned below and arranged at an angle of 90 with the arches 24. The exhaust gases passing under the arches 46 flow out through

necks

48 and 50, and are conducted into a. chamber 52 of the regenerator 38. The gas passing into the neck 48 flows through a conduit 54, Fig. 5, which connects the neck 48 with the neck 50. After the gasespass through the chamber 52 they flow through the superheating element 56 of the regenerator 38, where a part of the heat is generator 38 absorb substantially all of the heat of the blast gases, and the gases escape substantially cool through an outlet 50 at the top of the vaporizing element 34 (Fig. 2).

At the time the regenerator 36 is used for preheating the air, the regenerator 38 is used for absorbing the heat of the waste blast gases after they have passed through the fuel bed. The high temperature blast zone of the fuel bed is comparatively long, so that the blast gases contain a comparatively high percentage of carbon monoxide at the time they leave the high temperature zone. Therefore, the blast gases are burnable and it is necessary to obtain the heat of the combustion of the gases in order to retain the potential heat therein. To burn the blast gases air is conducted from the chamber 42 through a by-pass pipe 62 which is connected between the

chambers

42 and 52 immediately above the

necks

48 and 50. Preheated air passes through the by-pass 62 to be mixed with the exhaust gases leaving the fuel bed.

The chamber 52 gives a comparatively large space to promote the combustion of the ex-- zone located in the fuel column between the

arches

24 and 46, the air is cut off and water is admitted to the topof each of the regenerator vaporizing elements 34 through distributing cones 66, Figs. 1 and 3. The water is supplied to the cones 66 through pipes 68, but in case the vaporizing elements of the regenerators are not heated to a sufficiently high temperature to vaporize water,

steam may be admitted through pipes 70 to the cones 66. -By these connections either steam or water alone, or a mixture of steam and water may be admitted to the top of the vaporizing elements 34. The water is vaporized by contact with the refractory material to-the vaporizers 34 and the steam formed therein then passes through the superheating elements 40 and 56 .into the

chambers

42, and 52, respectively, of the

regenerators

36 and 38. The steam passing through: the

chambers

42 and 52 enters the shaft 18 through the necks,48 and 50, and

passes into the fuel column below the arches 46. By this arrangement the heat of combustion and sensible heat of the waste blast gases is conserved in supplying the heat of evaporationand the superheat of the steam used in gas making.

To confine the entrance of steam into the

necks

48 and 50,

valves

72 and 74, Figs. 1 and 3, are positioned in the

necks

26 and 28, respectively, to cut off the flow of steam into the fuel column below the arches 24. The steam passing under the arches 46 flows upwardly-through the high temperature blast zone in a path countercurrent to the pathof the blast gases, and the gas formed in the high temperature zone, together with any excess steam, then passes upwardly through the fuel column and leaves the top of the shaft'18 through an outlet 76. The hot gases passingthrough the high temperature zone furnish sufficient heat for carbonizing the coal in the column above the high temperature zone, and by the time the gases have passed through the column they are cooled and are in excellent condition to go into a scrubbing apparatus for the removal of the oils, tars, ammonia, and the like. The carbonization of the fuel in the column above may be effected.

During the gas making operation, water is sprayed into the fuel at the bottom of the shaft 18 bymeans of rings 78, which are po sitioned in discharge hoppers at the bottom of the shaft. The water is admitted to the rings 78 through pipes 82. The water sprayed into the column through the rings 78 acts to quench and cool the fuel and the steam formed in the quenching operation then passes upwardly through the fuel leaving the high temperature zone to cool this fuel, and simultaneousl form water gas. The water gas enters anc passes through the high temperature zone to be mixed with the steam being admitted below the arches 46. The unburned portion of the carbonized fuel and the ash after being quenched in the lower portion of the generator shaft is removed at predetermined intervals from the hoppers 80 at the base of the shaft through doors 81.

Doors 81 are preferably thrown open at alternate intervals for a sufficient period to completely empty hoppers 80 of the quenched carbonized fuel and ash which has accumulated therein, after which the doors are immediately closed. The arrangement of the base of the shaft and of the mouth of each hopper is such as to permit the only partially quenched charge to hang up to some extent over the mouth of the hoppers. For this reason when thehoppers are in turn emptied of'qucnched fuel the arch formed over the mouth of the emptied hopper will break only gradually as the fuel therein .becomes completely quenched by water and steam arising from the empty hopper, so that filling up of each hopper is radual rather than instantaneous, allowing or substantially continuous advancement' of the overlying column of fuel downwardly through the shaft.

In the ordinary commercial processes for making water gas a constant volume of steam is admitted to the generator during the gas making operation. Under these conditions a large volume of gas is made at the beginning of the gas making operation and this gradually falls off toward the end of the gas making operation. There is a small amount of excess moisture in the gas being made at the beginning of the gas making operation. and the amount of excess -1noisture constantly increases toward the end of the gas making operation. A large excess of moisture in the gas is not desirable because it is the source of a large heat loss. A large amount of heat is required to evaporate the water to form the excess steam, and

a large amount of cooling water is required to condense the excess steam out of the gas. In the present invention a substantially uniform quantity of excess moisture is maintained in the gas throughout the gas making operation by admitting a variable quantity of Water or steam to the fuel bed. the volume of steam being automatically decreased, and thereby the volume of steam being decomposed will be. substantially constant valve consists of a housing having a tapered plug 84 therein for controlling the flow of water through the valve. A stem 85 is secured to the plug and is arranged to be rotated by means of a torsion spring 86, which I is connected between the valve housing and the stem. At the beginning of the gas making operation the valve plug 84 is open to admit the maximum flow of water through the valve by means of a handle 87, and in opening the valve the spring 86 is wound up.

To permit the spring to rotate the plug in closing the valve, an escapement mechanism is provided, which is operated by means of a pendulum 88, to permit the closing ,of the valve in any desired time eriod. The escapement consists of a rate et wheel 89 secured to the valve stem 85, and a pair of pawls 90, secured to the upper end of the pendulum 88. By adjusting the pendulum weight the time period for the rotation of the valve plug 84 may be varied. With this construction a maximum flow of water will take place at the time the valve is opened, the pendulumwill be started, and the valve gradually rotated toward a closed position. Accordingly, the amount of water admitted per unit of time is gradually decreased, so that the amount of steam formed from the water in the regenerators is gradually decreased, and therefore the amount of steam entering the fuel bed is decreased. As the volume of steam decreases the velocity of the flow of steam decreases, and therefore the time contact between the steam and the carbon in the fuel bed is correspondingly increased. Thiswillpermit a substantially uniform quantitytoremainin the gas throughout the gas making operation. By arranging a series of gas generators which make a uniform volume of gas throughout the gas making period upon the supply line, the gas making .period of the various regenerators may be properly timed so that a substantially uniform volume of gas can be delivered to asupply line without the use of a gas holder. It is apparent that if the mechanism of the valves 83 is set to cause their operation to be reversed, the amount of water admitted to the regenerators or to the bottom of the generator would be gradually increased during the gas making period, and a substantially uniform volume of gas would be generated throughout the period.

The gas making capacity of the generator shown in the drawings depends directly upon the quantity of air which'may be forced through the high temperature zone to develop the required temperatures for gas making. By preheating the air in the regenerators the fuel column may be heated more rapidly but it has been found that temperatures of the fuel column much in excess of 27 00 Fahrenheit do not produce the best results for commercial operation. Accordingly, the air blast gases are passed through the regenerators at such a rate that they will have a-predetermined degree of superheat, in order to develop the ,proper temperatures in the fuel column. Preferably the air is admitted to a regenerator through the top of the vaporizing element, and passes through the'vaporizing element, superheating element and chamber in passing to the fuel column. If the re enerator superheating elements will provi e a sufiicient volume of heat toproperly preheat the air, the air from the conduit 32 may be passed through valves 91 to inlets 92 leading into combustion chambers 93 and 94, formed in the

regenerators

36 and 38 respectively, between the vaporizing elements, and the superheating elements. By this means the air will pass only through the superheating elements and the chambers in passing into the fuel column. It has been found that where the hot gases containing a substantial percentage of carbon monoxide are. introduced into a regenerator and directly into contact with a high temperature refractory material, there is a tendency to produce surface combustion in contact with the refractory. This surface combustion tends to develop such high temperatures that the regenerator refractories are often fused. The production of localized high tem eratures in the present regenerators is avoi ed by providing comparatively large combustion chambers at the point where air is mixed with blast gases in the regenerator, as for example, in the

combustion chambers

42, 52, 93 and 94 of the regenerators. In some cases the blast gases which are burned in the

combustion chambers

42 and 52 of the regenerators tend to develop very high temperatures in the chambers and in the adjoining superheating elements and the refractory material in the vaporizing elements is not heated to a sufficiently high temperature for eflicient operation. To overcome this difficulty the passage of air through the by-pass connection 62 from one regenerato'r to the other may be throttled or entirely cut ofi by means of a valve 95. At the same time preheated air may be led from one regenerator to the other through a conduit 96, Fig. 1, connected between the regenerator combustion chambers 93 and 94, to burn the blast gases as they pass from the superheatin g elements into the refractory of the vaporizing elements of the regenerator; The conduit 96 is provided with a valve 98 by which the flow of secondary air tothe combustion chambers 93 and 94 may be accurately controlled.

As described above, it is preferred to admit steam through both regenerators simultaneously during the gas making operation, in order that the steam ma be superheated as much as ossible and t us conserve the heat of the uel column in the formation of gas. In carrying on the operation, therefore, the steam will be given the preference to obtain the highest degree of superheat possible, and the air will be used to absorb the residual heat not taken up in forming steam and superheating the steam. The various connections by which'the temperature of ,the regenerators may be controlled permit an accurate preheating of the air and steam and provide a very high thermal efiiciency in view of the fact that practically all of the heat carried away from the fuel column by the blast gases is returned when preheating the air, and superheating the steam. If during the blasting operation the temperature of a regenerator is so reduced that it will not be effective in superheating steam, one preheated regenerator may be used alone for preheating the steam for the gas making operation. To this

end valves

100 and 102 are provided respectively in the necks 48 and 50 (Figs. 1, 3 and 5), and a'valve 104 is provided in the conduit 54, Figs. 1, 2 and 5.

With the construction illustrated in the drawings and described above, it will be obvious t at in place of blasting through the high temperature zone longitudinally of the fuel column, the blast may be directed transversely ofthe fuel column, the air entering under one arch 24 and passing out through the opposite arch 24, and the air entering under one arch 46 and passing out through the opposite arch 46. By this means the high temperature zone would be extended from above the arches 24 to'below the arches 46. It has been found, however, that by introducing the air around the major portion of the periphery of the fuel column and blasting downwardly, the fuel in the high temperature zone may. be heated more uniformly and the tendency to form clinker is materially diminished. Further, the introduction of steam around the major ortion of the fuel column during the gas ma 'ng operation provides a very uniform treatment of all the material throughout the high temperature zone and materially assists in uniformly treating the fuel throughout the column.

The

valves

72 and 74 in the

necks

26 and 28, the

valves

100 and 102 in the

necks

48 and 50, and the

valves

95 and 104 in the

conduits

62 and 54 are subjected to high temperature gases, and therefore, have to be made of the refractory material. The construction of these valves is shown more particularly in Figs. (land 7. The valve proper consists of of a block of refractory material 110, which moves through slots 112 formed in the conduits in which the valves are located. The valve 110 is connected with a head 114 which is secured to piston rod 116. The piston rod 116 is provided with a piston which is mounted on a cylinder 118, and the piston is preferably operated by hydraulic power. The valves 110 are preferably positioned in the lower portion of the conduits whereby they will tend .to open by'gravity and are positively moved into closed position by means of the hydraulic piston.

The water gas made when using steam for treating the fuel column has a heat value of approximately 300 B. t. uJper cubic foot. This heat value of the gas may be materially increased by carburetting the gas with oil, provided the cost of oil will warrant its use in carburetting the gas. If the gas is to be carburetted in the apparatus shown in the drawings, one regenerator would be used for preheating the steam while the other regenerator is used for carburetting the gas. To accomplish this the gas and vapor outlet 7 6 will be throttled so that a comparatively small amount of the gas is passed upward through the fuel column and practically all of the make gases are )assed through the superheating elements of the regenerator. An oil will be sprayed upon the refractory filling the regenerator elements from a pipe 120 located in the top of the regenerator elements. The superheating elements develop sufliciently high temperatures so that the oil will be completely vaporized and fixed and the gas may then pass out of the regenerator to the treating apparatus. The outlets 60 and 64 for the waste gases may be used for leading the make gases out of the regenerator or separate outlets may be provided for this pur ose.

During the blasting operation a large amount of ash and fuel is carried by means of blast gas into the

chambers

42 and 52 of the regenerators. If this ash and fuel is carried into the refractory materials of the regenerator they tend to clog the passage, and thereby cut down the efficiency of the regenerators. To overcome this the chambers 42 and'52 are extended below passa es 106 and 108 between respectively the

cham rs

42 and 52, and the superheating chambers 40 and 56. The blast gases passing from the

chambers

42 and 52 enter the superheating elements of the regenerators after making a right angle turn which tends to throw the solid material out into the chamber. The ash and the fuel collected in the

chambers

42 and 52 may be removed as desired through outlets 109, Fig. 3;

Although it is preferredto use a mixture of coal and coke in the fuel column to make a mixture of water gas and coal gas, the gas making method may be effectively carried on when coke alone is used in the fuel column. Any kind of coal and wood may be effectively used in the apparatus for making gas. Further, substantially the same apparatus may be used for distilling oil shale. When coke alone is used, the make gases consist only of blue water gas and the sensible heat of the gases being made is all used in preheating the fuel advancing to the high temperature zone. The apparatus described above is particularly effective in making blue water gas in that it provides an apparatus with a large gas making capacity and a high thermal efliciency.

The preferred form of the invention having been thus described, what is claimed as new is:

1. A generator for combustible gas comprising an upright unobstructed shaft, means for introducing fuel at the top of the shaft, means for the removal of material from the bottom of the shaft, a pair of heat regenerators each having vertically spaced directly connected and interchangeable air blast and exhaust gas connections with the midportion of the shaft, and valves in such connections by which air from either regenerator may be directed into either of the air blast connections, and by which exhaust gases may be directed from the shaft into either regenerator.

2. A generator for combustible gas comprising an upright shaft, means for admitting fuel at the top of the shaft, means for effecting the removal of material from the bottom of the shaft, means for introducing air to the mid-portion of the shaft, said shaft being arranged adjacent said air inlet to provide an opening around the major portion of the inner periphery of the shaft for the introduction of air into the fuel therein, means for removing air blast gases from the shellat a substantially vertically spaced distance from the air inlet to provide an elongated blast zone, means to apply water to the fuel at the bottom of the shaft, and automatic time-controlled means for varying the rate of introduction of water into the material in the base of the shaft.

3. A generator for combustible gas comprising an upright shaft, means for introducin fuel at the top of the shaft, means for e ecting the removal of material from the bottom of the shaft, means for introducing air at a mid-portion of the shaft, means for effecting the removal of air blast gases from the shaft through an outlet vertically spaced a substantial distance from the air inlet to provide an elongated blast zone, means to introduce steam into the shaft, and automatic time-controlled means to apply water to the fuel at the bottom of the shaft to quench the fuel andform steam for gas making.

4. A generator for combustible gas comprising an upright shaft, means for introducing fuel at the top of the shaft, means for efi'ecting the removal of material from the bottom of the shaft, :1 pair of heat regenerators each having air blast connections with the mid-portion of the shaft, a set of exhaust gas connections between the shaft and each of the regenerators at points in the shaft spaced asubstantial distance vertically from the air blast connections, a conduit directly connecting the said air blast connections, a conduit directly connecting the exhaust gas connections, means for introducing air into the regenerators, means forintroducing steam into the regenerators, and valves in said connections and conduits.

5. A generator for.combustible ras comprlsing an upright shaft, means for introducing fuel at the top of the shaft, means for effecting the removal of material from the bottom of the shaft, a pair of heat regenerators each having separate blast and exhaust gas connections with the shaft, means to pass air through a regenerator into the shaft, means to burn exhaust gases leaving the shaft in a regenerator, means for introducing water directly into the regenerators whereby steam is formed. means for passing steam formed therein through the regenerators into the shaft, and automatic time-controlled means for varying the rate of introduction of water into a regenerator.

'6. A generator for combustible gas comprising an upright shaft having means for admitting fuel to the top of the shaft, means mounted in the lower portion of the shaft for substantially continuously advancing,

fuel in a column through the shaft and for removing material from the bottom of the column, a pair of heat regenerators each having vertically spaced interchangeable air blast and exhaust gas connections with the mid-portion of the shaft to provide an elongated blast zone in the fuel column, valvecontrolled means directly associating certain of the interchangeable connections of one regenerator with the corresponding connections of the other re enerator in a manner to by-pass the said sha t, means for burning exhaust gases in said regenerators to recover their potential heat, means for introducing and distributing water into said heat regenerators to form steam for gas making, and valves in said connections for confining the admission of steam from the regenerators into the shaft and blast zone of the fuel column through the lower of said connections.

7. A generator for combustible gas comprising an upright shaft having means for admitting fuel to the top of the shaft, means mounted in the lower portion of the shaft for substantially continuously advancing fuel in a column through the shaft and for removing material from the bottom of the column, a pair of heat regenerators each having two vertically spaced interchangeable air blast exhaust gas and steam connections with the mid-portion of the shaft to provide an elongated blast zone in the fuel column, valve-controlled means operatively associated with each of the said interchangeable connections for directly connecting the two regenerators independently of the fuel column, automatic means for introducing 7 mounted in the lower portion of the shaft for advancing fuel in a column downwardly through the shaft and for removing material from the bottom of the column, a blast air inlet in the midi-portion of the shaft and an exhaust outlet vcrtically'separated a substantial distance from the blast air inlet to provide an elongatedblast zone in the midportion of the fuel column, means connected with the shaft for generating steam for gas making directly from heat regenerated from the blast gases, means for generating steam for gas making directly from heat regener= ated from the waste fuel in the lower portion of the column below the blast zone, means for passing the steam so formed into the high temperature blast zone of the fuel column to generate gas, means for passing gas formed by the steam upwardly through the upper portion of the fuel column, and means for withdrawing the gas from the top of the shaft.

9. A generator for combustible gas, commounted in the lower portionof the shaft for substantially continuously advancing fuel in a column through the shaft and for removing material from the foot of the column, a blast inlet in the mid-portion of the shaft and an exhaust gas outlet vertically separated a substantial distance from the blast inlet to provide an elongated blast zone in the fuel column, means for applying water to the base of the shaft at the foot of the column of fuel therein to regenerate heat from the waste fuel and to form steam for gas making, and automatic time-controlled means in connection with said water applying means for varying the rate of introduction of water into the lower portion of the fuel column.

10. In a water-gas generating apparatus, in combination, a gas generating shaft, and two heat regenerator elements each havingv interchangeable, vertically-spaced air blast and exhaust blast g'as connections with the shaft, each of said regenerators embodying acombustion chamber, a refractory filled heat storing and gas superheating chamber, and a refractory filled heat storing and water vaporizin chamber, a plurality of means for intro ucing airdirectly into at least two of the said chambers of each regenerator, and connections whereby the regenerators may be used interchangeabl for regenerating and storing sensible an potential heat of blast gas produced in the generator and for retunlin such heat to the generator in the form 0 preheatof blast air and aslatent and superheat of steam.

11. In a water gas generator, an upright refractory lined shell, means for supporting fuel in a column in said shell, the lining of said shell having two vertically spaced enlargements at points intermediate the ends of the shell providing vertically spaced annular openings between the lining and fuel supported inthe shell, means for selectively and simultaneously connecting the portions of the shell immediately adjacent the respective annular openings with a source of preheated air or preheated steam and with an exhaust gas line, and valve-controlled -means exterior of the said shell adapted to effect direct communication between the said source of preheated air and the exhaust gas line, and a gas outlet at the top of the shell.

12. A gas-making apparatus comprising a water gas generator, a conduit for conveying steam thereto, a valve in said conduit, automatic means operatively associated with the latter and adapted gradually to close the valve at a selected rate during the period employed for each steam run, the said automatic means comprising a resilient, valveactuating device and an adjustable member adapted to coact with the latter for regulating the rate of closing of the said Valve when so actuated.

13. Gas-making apparatus comprising a. Water gas generator, a conduit for conveying steam thereto, a valve in said conduit, automatic means operatively associated with the latter and adapted gradually to close the valve at a selected rate during the period employed for each steam run, the said automatic means comprising a valve-actuating device and an adjustable member adapted to coact with the latter for regulating the rate of closin of the said valve when so actuated. IIltGStImOIIy whereof I afiix my signature.

HENRY O. LOEBELL.