US2054154A - Method of manufacturing combustible gas - Google Patents

Description

Sept. 15, 1936. H. J. CARSON METHOD OF MANUFACTURING COMBUSTIBLE GAS Filed July 15, 1929 07% kotuwmv Patented Sept. 15, 1936 UNITED STATES METHOD OF MANUFACTURING COMBUSTIBLE GAS Hiram J. Carson,

Cedar Rapids, Iowa.

Application July 15, 1929, Serial No. 378,256

4 Claims.

This invention relates to the production of combustible gas and by-products such as oils, tar, and ammonia from bituminous fuel in gasproducers and the utilization of part or all of the gases so produced in boilers and furnaces and the recovery of any remaining gases for other uses.

The principal objects of the invention are to effect economies in such production and utilization by certain improvements in the methods employed.

The invention comprehends improved methods for: the production and recovery of rich distillation gas and blue water gas, and also oils,'tar, and ammonia from bituminous fuel in conjunction with the production of producer gas from the carbonized residue with the distillation gases and products drawn off with a controllable amount of or no admixture therewith of the producer gas; the utilization of part of the producer gas by combustion in regenerators for highly superheating steam for theformation of water gas, carbonizing the fuel and/or the production of ammonia; the use of air and/or oxygen in the carbonizing chamber for supplying a 25 part of the heat. required for carbonization and/or for the water gas reaction; the immediate utilization of part or all of the producer gas so formed by combustion in a boiler or furnace with the combustion products therefrom used for pre- 30 heating the air for such combustion and/or the air for the producer; the use of combustion products from the boiler or furnace and/or steam as an endothermal agent for controlling the fuel bed temperatures in the producer and the forma- 35 tion of combustible gas; an improved heat cycle in producers and boilers in combination whereby ,the gasification and utilization of the heat of combustion of the fuel-are carried on in a highly efficient manner.

Zlhe invention also contemplates the removal of ash from the producer in liquid form to thereby eliminate the usual temperature limitations because of the fusing temperature of the ash, and permit operation at relatively high fuel bed tem- 45 peratures and capacities and the use of cheap fuels with an avoidance of ash deposits in the boiler or furnace and the usual operating difficulties and expense in connection therewith.

To insure theeasy liquefying of the ash the 50 invention contemplates the use of preheated air in the lower zone of the fuel column.

The invention contemplates the use of a fluxing material which may be charged with the fuel or introduced in the bottom zone of the fuel column in any suitable manner such as blown in admixed with the blasting air as needed and desired. In the latter case the time interval required for fiuxing material charged with the fuel to work down to the slagging level is avoided.

The invention further contemplates the introduction of combustible gas with the blasting air in the bottom zone in case' of difliculty in slagging, which may for example be occasioned by a deficiency of. combustible in the fuel at the slagging level.

The blasting air may also be enriched with oxygen for further hastening combustion and liquefying the slag when desired.

'I'he invention also contemplates the use of part of the producer gas for the alternate heating of two regenerative chambers and the heat stored therein in turn employed for highly superheating steam to be delivered to and utilized in the carbonizing chamber or zone of the producer.

Other objects of the invention will more clearly appear from the description and claims hereinafter following.

In the drawing forming a part of theapplication, a suitable apparatus has been disclosed for the effective carrying out of the improved method or process. In said drawing, Figure 1 is a part vertical sectional view, part elevational view of a gas producer plant and associated steam generating boiler for effecting the complete cycle of steps of the improved process. Figure 2 is a part top plan view and part horizontal sectional view of the regenerators and generator shown in Figure 1, the sectional view of the generator corresponding approximately to the line A-A of Figure 1. Figure 3 is an enlarged vertical sectional view of the carbonizing chamber used in the gas producer and shown in Figure 1. And Figure 4 is an enlarged vertical sectional view, illustrating more particularly the details of construction of one of the air tuyeres, tuyere header and supplementary inlet valve associated therewith, shown is Figure 1.

The apparatus may now be described in detail.

In Figure 1, the gas producer I 2 is shown in section having mainly two zones. The lower zone I3 is the producer gas generating zone and contains mainly incandescent fuel. The upper zone contains a carbonizing chamber I4 which is charged with fuel and ash fluxing material, as limestone, when desired, through any suitable charging device as I5.

Air blast inlet means are shown at level I6 through valved inlets I611. and Ilia and also at level I! through valved inlets Ho. and Na.

Means for admitting steam at level I! when desired for use in controlling fuel bed temperatures is indicated at l8. Air supplied through l'la' may be mixed with the steam and admitted to the fuel at level I! as shown. Stack gas is preferably used as an endothermal agent for controlling fuel bedtemperatures. This may be injected under pressure at level I'I as through supply pipes 53 or inspirated by and mixed with air as indicated at inspirator l8.

In heating operations with the gas containing I a relatively high percentage of hydrogen a substantial portion of the total heat of combustion is lost in the latent heat of the water vapor in the resulting stack gases. The hydrogen content of the producer gas and the stack of water vapor loss are substantially reduced if. an endothermal agent such as stack gas containing little or no hydrogen is used.

The carbonizing chamber has an annular passage around it of a relatively large area, at 20 to lower the velocity of the gases leaving the incandescent fuel and reduce or avoid the carrying along of fine fuel particles in the gases. The annular passage is preferably narrowed at 2| to increase the velocity of the gases and heat transfer to the carbonizing chamber. The annular passageway 21! and 2! is preferably enlarged at 22 tate the downward passage of the fuel and avoid sticking or hanging. The carbonizing chamber preferably contains an assembly'26 in the center thereof. This assembly is shown enlarged in Figure 3, and is more fully described hereafter.

An inlet 2'? for steam is shown near the bottom of the carbonizing chamber, supplied by a vertically disposed conduit 28 passing through the assembly aforesaid and fed and supported by a pipe 29.. Pipe 2911 connected into pipe 29 indicates a means for admitting oxygen and/or air to the lower portion of the carbonizing chamber to supply any heat required for the water gas reaction and/or carbonization of the fuel.

An assembly cap or valve 30, adjustable as by a cable 3| for regulating the division of flow of gases through the assembly 26 andthe fuel is shown.

Two regenerative chambers 32 and 32a as indicated in' Fig. 1 and shown in Fig. 2 are connected to the passageway 22 of the producer through passageway 33 andvalved inlets 34 and 3411. These regenerative chambers are connected to a stack 36 and an air preheater 36a through valved outlets 35 and 3511. This preheater preheats the combustion air to the regenerators and has air inlet and outlet as indicated at 36a and 36a".

Each regenerator is adapted for the combustion of producer gas therein entering through passageway 33, valves 34 and Me with combustion air admitted through air inlets 31 and 31a into the respective combustion chambers, only one of which is shown and referenced 38. Each regenerator is equipped with valved steam inlet means 39 and 39a and valved steam outlet means 40 and Illa connected into steam supply pipe 29 leading to the carbonizing chamber in the producer.

The valved steam inlet means are equipped with pressure regulators 4! and Ma to control the pressure of steam admitted to theregenerative chambers. This control is effected by a pres sure pipe 42 opening into gas passageway 20 of the producer. The gas burner 24- is shown equipped with suitable air mixing means 24a for regulating the combustion air admitted through pipe 43; I

Combustion is effected. in the boiler combustion chamber or firebox 44 with the combustion products passing through the tubes and thence through opening 45 into an air preheater 46 having a stack outlet 41. The combustion chamher may be substantially reduced in volume with heat radiating surface provided as indicated by the line a with resultant economies. The combustion and producer. air may be supplied by a fan or blower 48 with preheated air .offtakelt from the air preheater leading to the boiler bumer 24 through pipe 43 and to the producer and regenerative chambers as before described.

stack gas passageways 50 and 5] are shown leading to a blower 52 for withdrawing the stacl-rgases either from the inlet or outlet of the air preheaters and delivering these gases through pipe 53 to level ll in the producer. When the air inspirating effect of the air admitted through Ila to inspirator i8 is relied on for drawing the stack gas into the producer, the blower 52 may be dispensed with. d

' The produceris shown with a hearth 54 preferably sloping toward a slag discharge opening 55 which is normally closed by any suitable means such as fireclay. A second slag discharge open- .ing 55a is shown at a higher level for use when iron or metallic ore is charged with the fuel as a i'iuxing agent.- The metal may be drawn off at the lower level 55 with the slag drawn off at the higher level 55a. v I

The pipe 56 opening into air inlet at level l6 indicates admission means for gas or oxygen for farther point as is desired.

In the partial plan view of Fig. 2, a generator section on theline A--A at level I6 in Fig. 1 is shown. Air inlet headers are indicated at l6 and I6, and tuyere openings in the long sides of the 1 generator section are indicated at l6". Doors are indicated at El opening into the generator through removable blocking as 62. The jets of air and stack gas and/or steam from the tuyres in the long sides of the generator practically cover the hearth thus insuring an active use of the entire hearth area.

In Fig. 3, an assembly 26 is shown in a fragmentalr section of the carbonizing chamber I4 with steam and/or oxygen and/or air admission means 21 supplied by pipes 28, 29 passing through the assembly as described for Fig. 1.

This assembly is preferablymade of a series of open cylinders or cones 66 of any desired form and preferably in the form of truncated cones with the bottom of each cylinder or cone projecting over and below the top of the next lower one thus forming a protective skirt around the upper end of the next lower cylinder or cone to prevent fuel falling therein and to provide annular openings 61 for the escape of volatile matter from the fuel into the open passage through the series of cylinders as indicated by arrows.

Fig. 4 shows a fragmentary section of a generator wall with an air blast tuyre therein. The tuyeres at each level are supplied by tuyere header pipes I I, which are supplied by air distributing pipe through valves 12. The tuyre nose I3 is shown projecting beyond the generator wall and cooled by water-entering through pipe 14 and discharging through pipe 'I4a.

The pipe 56, shown inserted in a tuyere, indicates means for the introduction of combustible gas or oxygen for mixing with the air and furthering combustion at this level.

Fluxing material in powered form may also be so admitted into the blasting air through pipe 56.

The improved process is carried out in the apparatus described, as follows:

A fire is kindled on the producer hearth 54 and the producer filled with fuel (preferably coke at the start) which is replenished with preferably bituminous fuel thereafter through charging opening 15. Valve 23, when provided, 7 is open. Air is admitted through tuyeres at level 16. At the start the lower slag opening 55 may be left open so some burned gases may be discharged here with a resultant drawing down of the heat to highly heat the hearth. As air is admitted and the fuel bed becomes hot the oxygen of the air is burned to CO2 at first and then decomposed into carbon monoxide mostly. This gas passes up through the fuel bed, preheating the fuel, leaving it at passage 20, and passing around the carbonizing chamber, passes out to the boiler through passageway 23 and burner 24.

Air for effecting combustion of this gas is admitted through 43. The gasis burned in com- .bustion chamber 44, and passing through the boiler enters the preheater 46 through opening 45. This preheater may be of the recuperative type but is preferably of the regenerative type and adapted for operation at high stack temperatures, say 800 deg. and more.

The burned gases in passing through the preheater 46 preheat the air admitted to the preheater as through fan 48, the preheated air being taken off at 49 and'supplied to the boiler burner through 43 and to the producer at levels l6 and I! as desired. As blasting with the air continues at level IS, the heat liberated by the burning of the carbon to carbon monoxide continually increases the fuel bed temperature. When the desired fuel bed temperature is reached stack gas drawn off hot at 45 ahead of the air preheater or at 5| in the outlet of the preheater may be valved inlets 31 and 3'|-a. While one regener-' ator is being heated, steam is admitted to the other through valved inlet 39 and 39-a, and is passed superheated through valved outlets 40 and 4lJ-a into the bottom of the carbonizing chamber through inlet 21. The highly superheated steam so admitted in contact with the hot carbon in the base of the carbonizing chamber forms some water gas and this with any undecomposed steam more or less blankets the bottom of the carbonizing chamber against the admission of the low grade producer gas.

The water gas and steam and/or producer gas I tillation gases which are drawn ofl at 58 may be effected.

The blue gas and steam and any producer gas mixed therewith in passing through the cylin-.

ders of the assembly produce a vacuum effect which draws the gas from the fuel being carbonized in through the annular spaces 61 into the stream of gas. The gas and vapors are accordingly withdrawn from the fuel substantially as evolved and, mixed with the blue gas and steam, leave the assembly through 38 and pass out through 58.

The heat for carbonizing the fuel is supplied by the sensible heat of the blue gas and any undecomposed-steam passing through it and the assembly and is supplemented by:

(a)The heat in the producer gas passing around the carbonizing chamber.

(b)--The use of additional amounts of excess steam preferably superheated to the highest practicable extent as above described. by the combustion of a portion of the producer gas in regenerative chamber.

(c)Passing part of the producer gases through the carbonizing chamber and using the sensible heat thereof, and/or 7 (d)Admitting air and/or oxygenmixed with or independent of the steam in the lower portion of the carbonizing chamber as through 21, or equivalent means for effecting combustion and the liberation of additional heat in the bottom zone of the carbonizing'chamber.

The carbonization temperature may accordingly be varied and controlled by the above methods of heating.

The hydro-carbon vapors are drawn off substantially as formed through assembly 26 and outlet 58 with a recovery of the condensible hydro-carbons in liquid form with little or no difliculty from the fuel arching or sticking during carbonizing. a a

The volatile matter of bituminous fuels is of varying composition and distillable at different temperatures. The volume and quality of the volatile matter given off varies with the temperature and time of heating. When the volatile matter distilled oil at relatively higher temperatures passes through cooler fuel some or all of it is condensed on the, cooler fuel. This condensate incases the lumps or particles of fuel in a liquid envelope often of a plastic nature which is not again vaporized until the fuel passes into a zone of higher temperature. Meanwhile the lumps and particles contain volatile matter distillable at relatively lower temperatures which,

,' being partially :or wholly confined within the condensible portion of these hydro-carbons may be recovered in liquid form.

With the hydro-carbons drawn off as formed and cracking avoided, the heat required for car-=- bonization is substantially less.

The invention contemplates the distillation of the fuel under controllable temperature conditions to permit the evolving and recovery of condensible hydro-carbons of varying qualities as desired.

The passage of the producer gases around the carbonizing chamber insures the relativelyrapid heating and carbonization of the fuel in contact with the chamber wall. The admission of highly superheated steam and/or air and/or oxygen in the lower zone of the carbonization chamber and its passage through the fuel and the assembly insures the drawing off of the volatile matter under temperature and partial pressure conditions which avoid condensation and permit the recovery of the oils'and rich gases. The use of suflicient undecomppsed steam, assistsin the devolatilization of the fuel and results in the formation of ammonia, which mixed with the rela tively small volume of rich gases is easily recoverable. 5

The steam or stack gas enters the fuel at level II, asufficient distance above level-J6 so as to bypass the lower intensely hot zone without an appreciable cooling action on any liquid slag in that zone.

With the producer, boiler, and regenerators at the desired temperature throughout for regular operation, highly superheated steam and/or air or oxygen is admitted in the bottom zone of the carbonizing chamber and the resultant gases, oil vapors, and ammonia are continually drawn off at 58, the carbonized fuel descends into the producer gas generating zone i3, where it is con tinually blasted by highly preheated air from air preheater 46, with the temperature controlled by steam or stackgas separately or mixed with air admitted at the higher level for controlling fuel bed temperatures.

Any fluxing material, as limestone, charged with the fuel for lowering the melting point of the ash has the additional advantage of furthering. the production of ammonia. It also carries down a substantial part of the sulphur in the fuel ,into 'the slag.

With the stack gases leaving the boiler at relatively high temperatures and used for preheating air, the boiler heating surface 44a provided operates at a higher temperature differential with an increase in heat'transfer per unit of heating surface. With stack gases preferably hot used as an endothermal agent in the producer, practically all the sensible heat in this portion of the stack gases is returned to the process. The higher the preheat in the air to the producer, the greater is the cooling action required for keeping the fuel bed temperature down to any desired point. The hotter the'stack gases used as an endothermal agent, the more of these gases may be used for a given amount of cooling and the more nearly is an approach made to a closed heat cycle with a reduction in the volume of ducer insures a relatively higher mass of the air to be preheated than in the outgoing stack gases, with a more nearly complete'recovery of heat in the waste gases than is obtainable with usual methods.

The use of a portion of the producer gas for combustion in regenerators for superheating steam further increases the mass of the air to bepreheated in proportion to the stack gases -from the boiler or furnace.

The air preheater SG-m recovers any otherwise waste heat from'the regenerators and preheats the combustion air for the regenerators. When this preheater is used the. valve 49a in Fig. 1 is closed. When air from preheater 46 is used in the regenerators valve 36a" is closed.

,The invention provides for the production, utilization and recovery of combustible gases and by-products of various qualities from a variety of carbonaceous fuels.

The steam superheating regenerators may be dispensed with whenever it is desired to immediately burn all of the gases produced, in. which case the upper zone of the producer forms the carbonizing chamber with chamber It omitted and the fuel filling the entire upper space.

Combustible gases of different qualities may be produced and recovered, and the steam superheating regenerators dispensed with when the needed heat for carbonizing the fuel is supplied by passing the required amount of producer gas and/or air and/or oxygenthrough the carbonizing chamber. 1

The economics and advantages of the difierent features of my invention are obvious:

Provision is made for the recovery of rich gas, oils, tars, and ammonia from bituminous fuel whichis now lost orburned in boiler and other furnaces.

The use of controllable amounts of highly superheated steam and/0r air or oxygen and the withdrawal of vapors without condensation insures the rapid carbonization of the fuel.

The more valuable constituents of coal are recovered for higher uses with the low grade carbonized residue gasified and immediately used in boilers'or furnaces.

The present limitation in producer gas production occasioned by a fusing temperatureof the fuel ash is definitely removed by removing the ash in liquid form.

Cheap, abundant fuels are made available for gas production.

Theme of the fluxing material as limestone for liquefying the ash has the additional aiilrantage of furthering the production of ammonia and methane, and carrying sulphur into the slag.

The usual dimculties due to the sticking and with the temperature therein controllable within the optimum limits for ammonia formation.

The different features are all combined toprou vide methods for the production and recovery oi. rich gas and byproducts from the coal at relatively high rates in apparatus of a given size with the eflicient production and utilization of producer gas in a partially closed heat cycle.

reduction in radiation losses.

The use of stack gases as an endothermal agent limits the formation of hydrogen and lowers the stack losses by reason of the decreased water vapor content in these stack gases. 1

With the gas used hot as it leaves the producer and mixed with air heated to a relatively high temperature combustion is greatly accelerated and the combustion space required for a given capacity is substantially reduced with a resultant The heat radiating power, of the carbon monoxide flame is relatively high and with the provision of heat radiating surfaces in the combustion chamber, extremely high rates of heat transmisson to the boiler or furnace material are obtained.

The reduction of the fuel to ash in the producer results in a relatively ash free gas being delivered to the boiler or furnace with a result that the heating surfaces remain clean for an indefinite period, and the frequent shutdowns, maintenance expense, etc. in present boiler practice necessitated by ash deposits on the heating surface and the annoyance and expense caused by the discharge of fine ash with the stack gases is avoided.

From the preceding description, it is evident that the improved method makes possible: the recovery of the valuable gases and by-products of coal now used in boilers and furnaces on a large scale for higher uses with the immediate consumption of the relatively low grade carbon residue and the highly efiicientand practically continuous operation of high capacity boilers and furnaces.

While I have herein referred specifically to steam generating boilers and. furnaces, it will be understood that the invention is equally applicable to other heat utilizing devices, by which term heat utilizing devices as used in the description and claims, I mean devices for accomplishing useful or productive results independent of the producer gas generating process proper, that is, useful results extraneous of the gas making cycle proper.

Having described my invention, I claim:

1. In the manufacture of combustible gas from bituminous fuel in apparatus including a gas producer having an upper carbonizingzone and a lower producer gas zone and two regenerators, the improvement which consists inair blasting the column of fuel in the lower portion of the producer gas zone, drawing off the pro-- ducer gas formed thereby from the upper portion of the lower zone substantially without contact with the fuel in the carbonizing zone, burning a portion of the producer gas alternately in each of the regenerators, admitting -steam alternately to each of the regenerators,

passing the steam highly superheated therein from the regenerators to the lower portion of the carbonizing zone and thereby substantially blocking ofl admission of producer gas to the carbonizing zone, passing the steam through the carbonizing zone, drawing off the distillation gases liberated thereby and admixed therewith from the top of the upper zone, and drawing ofi ash and clinker forming material as liquid slag.

super-heated steam and an oxygen-containing fluid to the lower portion of. the carbonizing zone; and passing such steam and fluid upwardly through the carbonizing zone and drawing off the generated and distilled gases liberated thereby and admixed therewith.

3. The herein described improvement in the method of manufacturing combustible gases from carbonaceous fuels in gas producers having an upper carbonizing zone and a lower producer gas zone which includes: continuously air blasting the column of fuel in the lower portion of the producer gas zone and maintaining the slag liquid; drawing off the producer gas thereby formed'from the upper portion of said lower zone substantially without contact with the fuel in the carbonizing zone; admitting superheated steam substantially centrally and at the bottom of the fuel in the lower portion of the carbonizing zone; and conducting the steam admixed with the formed and liberated gases from the fuel through an apertured passage within the fuel in the upper portion of said carbonizing zone and simultaneously drawing into such admixed steam and gases, the vapors and gases when and as distilled and released from the fuel in said upper portion of the carbonizing zone.

4. In the manufacture of combustible gas from carbonaceous fuel in a generator wherein the fuel descends first through a distillation zone and thence into an incandescent, up airblasted zone with resultant generation of producer gas therefrom, the improvement which consists in: confining the fuel in its passage through the distillation zone to a continuous solid column of substantially annular form and advancing the fuel downward through said annular column formation solely by gravity; continuously heating said annular colum'n portion of the fuel throughout its entire height by passing the generated producer gas vertically upward along the outer side of the annular column portion of fuel but without contact of said producer gas with the fuel in the annular column portion; and, simultaneously with said heating by the producer gas, introducing highly heated fluid into the fuel at the lower portion of said distillation zone, passing said fluid upwardly through said annular column portion of the fuel to effect distillation thereof throughout its HIRAM J. CARSON.

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