US1670102A - Process for making producer gas - Google Patents

Description

May 15, I928?" 11670102 H. L. DOHERTY IERQCESS FOR MAKING PRODUCER GAS Filed Sept. 8, 192g 4 Sheets-Shet 1 May 15, 1,928. 1,670,102

H. L. DOHERTY PROCESS FOR MAKING PRODUCER cms Filed Sept. 8. 1 4 Sheets-Sheet 2 H. L. DOHERTY gnocEss FOR MAKING PRODUCER GAS Filed Sept. 1920 4 Sheets-Shet 4 Patented May 15, 1928.

UNITED p v 1 1,670,102 r'rau'r FFHCE.

HENRYL. nonaarv. or new YER-3,151. 1r.

PROCESS FOR MAKING PRODUCER GAS.

Applicatidn flied September a, 1920. Serial No. 408.971.

' This invention relates ,to -a* process for making producer gas and more particularly to the operation of gravity feed gas produclers for burning inferior grades of sof coa Most of the gas producers in use at the present time consist of a vertical shaft for supporting a column of fuel and mechanism for burning the coal by a blast of air forced through the-fuel under pressure. 'Some of the producers in use operate at such high temperatures that the ash of the coal is formed into and withdrawn from the producer as slag. Other producers do not operate at the high temperatures of slagging producers but the temperatures are sufli ciently hi h to form large c'linkers which are very difficult to remove from the producers. With both the slagging and clinkerforming producers, the slag and clinkers accumulate so that the producers have to be periodicall cleaned. The accumulation of slag and clinker and any intermittent operation of the producers tend to produce su stantial variations in the quality of the gas being made. y

The primary object of the present invention is to provide a process of making producer gas by which a uniform quality of gas may be continuously produced without the-objections above referred to..

Another object of the invention is to pro.- vide forv the continuous operation of a gravity feed gas producer without the format-ion of clinkers.

Another object of the invention is to provide for the efficient operation of a gravity feed gas producer with an induced draft.

With these and other objects in view, the invention consists in the process of making producer gas hereinafter described and particularly defined in the claims.

The various features of the'invention are illustrated in the accompanying drawings in which, v

Figure 1 is a view in front elevation of a gravity feed gas producer embodying the preferred formof the invention;

' Fig. 2 is a view in side elevation of the gas producer shownlin Fig. 1;

Fig. 3 is a view of the gas producer in horizontal section taken on the line 3-3 of Fig. 2; and V I Fig. 4 is a detail view in perspective illustrating the fuel-distributors, thejvertica'l grates, and the device associated with the grates for returning fuel back into the producer which has passed through the grates,

The preferred form of the invention embodies a gas producer of the type which is adapted to make gas for direct consumption in heating steam boilers. The gas producer illustrated in the drawings may be properly called a double producer in that two distinct vertical columnsof fuel flow by gravity downwardly through the pro-.

ducer and the apparatus for treatin the fuel to make gas is the same in each co umn. The producer proper consists of a' vertical rectangular shaft which is supported in a structural steel framework (see Figs. 1 and 2). The front wall '10 and rear wall 12 are made of a fire-resistant masonry construction and the major portion of the upright longitudinal sides of the producer shaft consists of vertical open grates 14. The fuel burned in the roducer, which usually consists of an in erior grade of soft coal, is

held in a hopper 16 ositioned on the top of the producer and I owe from the hopper down through distributors 18 into the body portion of the producer. The distributors 18 extend along the full length of each side of the producer and'discharge fuel into the producer immediately below an ignition fire arch 20 which constitutes the top of. the producer. The fuel emerging from the distributor's 18 spreads'out toward the central ortion of the producer alon a dot'and ash line 22, indicating the ang e of repose of the fuel and is ignited by the aid of radiation from the arch 20.

Theproducer as generated in the shaft is removed from t e top of the fuel column through an opening 23 (the outline-of which is shown by dotted line 21 in Fig. 1) formed in the rear wall" 12 of the producer immediately below the fire arch 20. The. producer gas formed in the producer passes upwardly throughout the length of the fuel column and preferably passes out of the producer;

while hot, directly into a combustion chamber toibe burned. p

The coal hopper '16 (Figs. 1 and 2) consists of a box-like structure which is supported upon andcovers the top of the producer. The hopper is divided longitudinally into ten sections, there being ave sections along each side of the producer, and;the width of a'section corresponds to the width of a distributor 18 (see Fig. 4 Each sec= are tion has downwardly inclined-sides 36 which merge into a fuel chute 38 positioned in the upper end of the distributor 18. The hoppers are supported principally by the distributors 18 and the distributors 18 are supported upon I-beams 35 (Fig. 4) which extend longitudinally of the producer. When the producer is in normal operation, the fuel passes in a slow and substantially continuous stream from the hopper through the chutes 38 into the distributors 18. If, however, it becomes necessary tocheck or stop the operation of the producer, the flow of fuel from the hopper into the producer may be stopped by means of gates 40 which are pivoted to the opposite sides of the distributors 18 and arranged to swing under the open end ofthe chutes 38. To move the gates 40 into and out of position under chutes 38, a rack 42 is formed on the bottom of the gates the teeth of which mesh with pinions 44 fixed on shafts-46 journalled longitudinally of the distributors 18. The shafts 46 extend outwardly be ond the front end of the producer and may e manually operated by means of chains 50 which run over sprocket wheels 52. When the shafts 46 are rotated by the chains 50, all of the gates will be simultaneously moved -to close or open the fuel chutes 38.

The air and other gases for controlling combustion of fuel in the producer are in duced through the producer by an induced draft which preferably will consist of an induced draft fan located at the flue gas outlet of the steam boilers being heated. Since the fuel, is .quite open in the upper portion of the producer, the highest temperatures of combustion take place in the fuel as it advances from the distributor to the mid por-' tion of the producer. At about the midportion of the distributors 18 is divided into two columns and is supported on one side'bythe'grates 14 and on the other side by inverted V- length of the producer. By the time the fuel has advanced downto the upper portion'of the V-shaped grates 24, the percentage of ash in the coal has increased and the bed is much thicker so that the resistance to the air for combustion is quite high, thus tending to lower the temperature resulting from As the fuel advances clownwardly to a point where the percentage of ash is high enough to form a clinker with high temperature combustion, the ventilation is cut down to lower the temperatures below that at which the fuel containingash will fuse. After the fuel moves down below by refractory walls so that any gases for controlling combustion in the shafts must enter through the bottom. The fuel emerging from the shafts 26 runs onto grates 28 roducer the fuel from the which are spaced below the lower ends of the shafts 26 a considerable distance to allow the fuel to spread out and open up. The grates 28 are open and gaseous products of combustion, which consist of flue products from a boiler, are introduced through a conduit 30 and pass up through the grates 28 into the shafts 26. The fine products ad mittcd from the conduit 30 act to cool fuel and ash in the shafts 26 by absorbing sensible heat and carrying it toward the upper portion of the fuel column. When the flue gas comes in contact with the hotter portions of the fuel column, the carbon dioxide will be dissociated with an endothermic reaction and the dissociation products will absorb heat from the fuel column and act to cool the mixture of fuel and ash in the column. In some cases it may be desirable to introduce flue gases through the grates 24 to control the temperature of fuel in the midportion of the producer immediately above the grates 24.

When burning coal producing some kinds of ash, especially if the ash content is high, it will be necessary to pass the fuel through the producer at such a rate that unburned carbonized fuel will be discharged from the bottom of the producer in order to prevent the formation of clinkers. With coals which are low in ash and other coals having a high ash content of a particular character, it may be desirable to pass the fuel through the shaft at such a rate that the coal or fuel will be entirely burned'to ash before it is discharged from the bottom of the cooling shafts 26. Vith the coals having a low ash content, a, slow rate of combustion may be maintained in the cooling shafts 26 to entirely burn fuel to ash before it reaches the bottom of the shafts. In this case. sufficient air is introduced with the return flue proclucts entering through the conduit 30 to maintain a slow combustion in the .shafts 26. To prevent' the formation of cli'nkers when burning a coal-having a high ash content, the grates 28 are arrangedfto be reciprocated to discharge the fuel emerging from the shafts 26 at such a rate that unburned carbonized fuel will be discharged from the grates to be collected in the hoppers 34. Any carbonized fuel collected'in the hoppers 34 may beremoved' from the ash by screening and returned to the hopper 16 to be mixed with fresh fuel and again passed through the producer.

The capacity and efficiency of most boiler grates and gas producers depends directly upon theamount of coal which may be burned per square foot of grate surface. The-vertical grates 14 which extend along the greater portion of the longitudinal. sides of the fuel columnsafford an enormous grate area for admitting the necessary air for supportingthe combustion of the fuel;

The grate 14 consists of a series of vertical bars 54 (Figs. 1, 2 and 4) which extend between the lower end of the distributors 18 and the upper end of the cooling shafts 26. Slots 56 and 58 are formed in the ends of the bars 54 which are arranged to cooperate respectively withrods 60 mounted in the distributors 18 and ribs 62 formed on the u per face of a channeLbe-am 64 mounted a ong the sides of the gas producer frame. The

slot 56 is sufficiently elongated so that the bar 54 may be raised vertically to clear the rib 62 and'thus be removed from the side of the gas producer. When the bar 54 is in normal position, it will be held by gravity in contact with the rib 62 and thus prevented from becoming displaced. Although the grate bars 54 are shown as supported in a vertical position, this position is not essential since the bars may be supported in any inclined position at which the fuel on the grates will run by gravity.

The spacing of the grate bars 54 is important m that the spaces between the bars may be utilized for controlling the flow of air therethrouglh to control the rate of combustion. As t increases, the resistance to the passage of gases through the bed for controlling combustion increases. Accordingly, ifthe fuel bed is more open at the top than toward the bottom, it may be desirable to have the spaces between the grate bars at the bottom of the grates larger than the spaces between the bars at the top of the grates.

Again, it may be desirable to maintain a slower rate of combustion in the lower portion of the fuel bed in which case the spaces between the grate bars at the bottom of the grates would be as small or smaller than the spaces between the bars at the top of the grates. To provide for these various factors, the bars may be made in any shape to give the desired ventilation area at different vertical levels of the grates.

Most of the coal used in gas producers is of an inferior grade and is often in the form of small granules. If the coal is a non-coking coal, such as lignite or anthracite, it will readily pass between the vertical bars of the grates 14 while burning. However, if the coal is a coking bituminous coal, it will tend to fuse to form coke when being heated in the upper portion of the producer, and there will not be such a great tendency for such fuel to run out between the grate bars. To prevent coal from running out of the producer through the grates, louvers 68 (Figs. 1, 2 and 4), are positioned in front of the grates in vertical rows with the inner edge of the louvers in engagement with the outer face of the grate bars 54. The louvers have a length substantially the width of the fuel distributors 18 (Fig. 2) so that there are five rows of louvers at the side of each of the e ash content of the fuel bed spaced vertically at such a distance and have v such a width that they will support fuel running through the grate at its angle of repose and prevent the fuel from going beyond the louvers. The fuel passing through the grates may be incandescent and thus the grates will be embedded in a body of incandescent fuel and will be liable tovbe burned out. To prevent this, the louvers are cupshaped and immediately above each longitudinal row of louvers at the side of the producer, is positioned a water pipe 70 by which water may be delivered to the louvers to uench the fuel and cool the grates. Water owing on the fuel of the louvers will'be converted into steam and the steam will be drawn through the grates by the induced 2 converted into water gas. I I

Although the fuel collected in the louvers is cooled with water, the heat of the fuel columns will slowly burn the fuel so that the louvers will generally become filled with ash. The accumulation of ash on the louvers, especially when burning a non-cokingcoal, will tend to form ash inside of the grates so that it is desirable to keep the louvers as free sis-possible of ash to keep the grate bars from becoming clogged and thus cut down the ventilation of the .fuel column. To remove ash collecting on the louvers, the louvers are pivotally mounted between vertical bars 72 which are connected at their upper ends to the I-beam 35 and at their The steam entering the fuel columns will be lower ends to the channel beam 64 (Figs. 1, 2 V

and 6). Lugs 74 are formed on the lower side of the louvers which are, connected by means of chains 76 to actuating rods 78. The upper ends of the rods 78 are connected by means of chains 80v with pulleys 82 which are fixed on horizontal shafts 84 journalled on the side of the I-beams 35 (Fig. 1). The front end of the shafts 84 extends outwardly beyond the front of the producer and are arranged to be rotated by means of handchains 86 which run over sprocket wheels 88 fixed on the outer end of the shaft. When the shaft 84 is rotated by the hand-chain 86, all of the louvers on one side of the produccr will be simultaneously tilted to dis charge ash against the outer face of the grates.

The ash discharged from the louvers is collected in a pair of hoppers 90 which are positioned along each side of the producer at the bottom of the vertical grates 14. The spout of the hoppers 90 is positioned directly over discharge openings 92 which are formed in box-beams 94 constituting a portion of the lower part of the structural frame-work. Since fuel or ash is discharged only periodically from the louvers, the openings 92in the box-beams arenormally closed by covers 96 to prevent returned flue gases from escaping from the producer or to prevent air from being drawn into the producer. When ash, fuel, or a mixture of ash and fuel is being collected from the louvers in the hoppers 90., the spouts of the hoppers are closed by means of gates 98 and when it is desired to discharge ash from the hoppers 90, the covers 96 are removed and the gates 98 opened to allow ash to run down inside of the producer to be collected in the ash hoppers 34.

The inverted V-shaped grates 24 posi tioned in the mid portion of the producer act to separate the lower-portion of the fuel into two distinct columns and since the grates extend the entire length of the producer, they provide an enormous grate area for supplying gases for controlling combustion to the mid portion of the fuel. The grates 24 (Fig. 1) consist of a series of bars 100 which are supported between an arch beam 102 and a foundation beam 104. The grate bars 100 are provided with a notch 114 at their upper ends and with a beveled face 116 at their lower ends which cooperate respectively with flanges 118 on the lower edges of the arch beam and with a lug 120 formed on the upper face of the foundation beams. The notches 114 have suflicient depth so that the bars may be moved longitudinally to permit them to be moved over the lug to be removed from the producer.

To prevent fuel from running through the grates 24, louvers 122 having a construction similar to the construction of the louvers 68 are positioned in rows along the outer face of the grates 24, there being one row of louvers for each section of the arch beam 102. The louvers 122 are pivotally mounted and are adapted to be rotated to discharge ash therefrom. To rotate the louvers, chains are connected to lugs formed on the bottom of the louvers and pass over pulleys fixed on a shaft 128. The outer end'of the shaft 128 extends outwardly beyond the front of the producer and is arranged to be rotated by means of a hand-chain 130 which passes over a sprocket wheel 132 fixed on the outer end 'of the shaft. To quench fuel passing through the grate bars 100 intothe louvers 122, a series of water pipes 133 are positioned in front of the longitudinal rows of louvers and arranged to direct water upon fuel in the louvers.

The fuel discharged from the louvers 122 passes downwardly along the grates 24, across the inclined face of the beam 104, and falls upon a floor 134. The fioor134 is po sitioned adjacent the lower ends of the cooling shafts 26 and is supported at its opposite ends by beams. 136 .(Fig. 2) whichspan betweenbox-beams 138. The boxbeams 138'. extend from the front to the rear of the prof dp'c er bymean's of a-rrocker-arm 174.

ducer parallel to the floor 134 and are supported 0n girders 140 (Figs. 1 and 2) which are positioned in the front and rear walls of the framework. Upon the box beams 138 are positioned refractory masonry walls 142 which support the foundation beams 104 of the grates 24. The side walls 142, grates 24 and floor 134 constitute a tunnel by which gas for-controlling combustion may be supplied to the grates 24 and by which ash discharged from the louvers 122 may beremoved from the producer. The front end of the tunnel is closed by ventilation doors 144 by which air may be admitted in regulated amounts to thetunnel to pass to the grates 24. The floor '134eonsists of a series of inverted T-bars 146 which rest on the beam 136 and are spaced apart a distance equal 'to the length of brick, the space between the bars 146 being filled with brick 148. Instead of removing ash falling upon the floor 134 through the tunnel doors 144, it may be discharged through openings 15-0, formed in the floor by removing bricks 148 therefrom (Fig. 3), and collected in the hoppers 34.

After the fuel moves below the grates 14 and 24 and while it passes down through the shafts 26, the only ventilation given to the 'fuel is that which isadmittecl. at the bottom of the shafts. The front side of the supporting beams 104 and the walls 142 (Figs. 1 and are made of arefractory n'iasonry construction and the steel frame structure opposite the walls 142 is lined with refractory construction to protect the same from heat. 0

The reciprocatory grates 28 for discharging carbonized fuel from the bottom of the fuel columns consist of a series of gratebars 152 (Fig. 1). The grates 28 are secured to I-beams 158 and the I-beams 158 for each grate are bound together by transverse beams 160 to form a 'reciproeatory frame. The portion of the beams 160 be tween the I-beams 158 are arranged, to roll upon rollers 162, which are loosely jourgrates have sufficient width to support ash emerging from the shafts so that it will not run down from theshafts'while the grates are stationary. At the time the grates are reciprocated the "ash is discharged alternate- 1y at the sides of the grates.

Thereeiprocating motion of the grates 28 and the frame 158160 is imparted by meansof hydraulicengines 168 which are mounted on the front of the producer. The pistons of the hydraulic engines 168 are connected b a rod 170 and the reciprocating motiono the rod .170 is impartedto a shaft 172 journalled longitudinally of the rpupper end of the arm 174is fixed to the shaft 172 and a roller 175 is journalled in the lower end of the arm which engages collars 176 adjustably mounted on .the rod 170.

To impart the motion of the shaft 172-to the grates 28, cables 178 are connected to the opposite ends of the beams 160 and pass over cam-arms 180 which are fixed on the shaft 172 immediately below the beams 160 (Fig 1). The cables 17 8 are securely attached to the cam-arms 180 and the oscillating move-- ment of the cam-plates caused by the hybe inserted through the doors 182 extending along the entire length of the grates (Fi 2). Y

T e flue gases entering the producer through the tube 30 may be positively forced through the tube by means of a blower or fan and ma be controlled by means of a valve 184. he lower ortion of the producer is closed so that t e only ath for the passage of flue gases-is upwar ly throu h the grates 28 and into the cooling shafts 26. In this wa the carbon dioxide of the flue gases may be used to control the temperature of combustion in the shafts 26. In some cases, however, it may be desirable to admit flue gases through the V-grates 24 and to accomplish this bricks 148 may be removed from the floor 134 below the V-.

grates to provide openings such as 150 for ue gases to pass up into the grates 24. The

size of the openings 150, however, may be accurately controlled or easily closed by plates 151 to control the passage of flue gases through the grates 24. The main air supply for supporting combustion which passes through the grates 24 is admitted through the ventilation doors 144.

In view of the above description, it will be seen that the air for supporting and controlling combustion may a1 be drawn through the producer by induced draft and pass through the vertical grates 14, the V grates 24, and the discharge grates 28. Likewise the flue gases for controlling combustion all be drawn throu h the producer by ma 7 ind uced draft and pass t rough the V-grates 24 and the discharge grates 28. This grate area is exceedingly arge in comparison with the grate areas of the usualproducersand furnaces and thus allows a very large- If the fuel or ash amount of fuel tobe consumed in making as in relation tothe floor area of the proucer. Further, this arrangement of the grates supports the fuel. columns so that all parts of it may be properly supplied ,with air or returned flue pro ucts. J i

In some of the claims the word upright is used-to define the arrangement of the grates 14 and'24. By the wordffupright it is intended to mean any grates which are supported in a vertical positionor inany inclined position at which the fuel onthe grates will flow b gravity. F

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

1. A process of making'producer gas, com-- I upri ht sides of said column to. romote gas making reactions therein, contro ling the air supply to maintain the highestgas makin temperatures in the upper portion of the co f umn, removing producer gas formed adjacent thetop of the shaft, introducing [flue gases for controlling combustion into ithe ower part of the fuel column; and. controlling the movement of flue gases upwardly through the fuel column to cause a lowering of temperature in the fuel asit advances below the mid-portion of said column.

2: A process of making producer gas, comprising passing fuel in a column downward- 11y through a shaft, drawing air under inuced draft into said column over a substantial portion of its upright lateral area to promote gas 'making reactions therein, re-' moving t e producer gas formed adjacent the top of the shaft, maintaining the highest combustion temperatures in the upper part of said column, introducing flue gas into the lower portion of said column maintain the temperature therein below the fusion point of the ash, and decreasing the advances downwardly to progressivel retard the movement of flue gases an air therethrough. p

3. A process of making producer gas, comprising passing fuel in a columndownward. ly through a shaft, heating the fuel at the top of the column by radiation, introducin air into a major portion of the longitudina sides of said column to promote gas ma'king' reactions therein, removing the-producer gas formed adjacent the top of the shaft,con-' trolling the air supply to maintain the-highest gas makingj'temperatures in the upper portion of the column, sup lying air 'at a reduced rate to the fuel 00 umn below the mid-portion to maintain a combustion temperaturetherein below the fusion'point' of;-

the ash, supplying flue gases for controllin I combustion throughout a major portion 0 1 89 m cross-sectional area of the fuel column as it the lower artof the fuel column and ad- 'mitting su cient oxygen with said flue gases to maintain a slow combustion in the lower portion of said column. I

4. A process of making producer gas, comprising passing fuel in a column through a shaft, introducing air under induced draft into the upright sides of said column to maintain high gas making temperatures in the top portion of said column and progressively lower temperatures of combustion in the fuel column as it advances downwardly, removing producer as formed adjacent the top of the shaft, re ucing the air supply to the lower portion of the fuel column. and passing gases for controlling combustion upwardly therethrough in amounts sufficient to prevent the formation of clinker in the zone of the fuel column where the ash attains a suflicient percentage for clinker formation.

5. A process of makin producer gas, coni- 'prising passing fuel su stantially continuously in a column downwardly through a shaft, admitting air under induced draft to a major portion of the longitudinal sides of the column to promote as making reactions therein, controlling t e air supply so as to maintain the highest combustion temperatures in the upper portion of the fuel column, removing producer gas formed adjacent the top of the shaft, cooling the fuel in the lower portion of the column by promoting endothermic dissociation of flue gases in direct contact therewith, and controlling the rate of advancement of fuel through the shaft and the volume and character of gases passed counter-currently thereto.

In testimony whereof I afiix my signature.

HENRY L. DOHERTY.

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