US2622972A - Gas producer and method of operation - Google Patents

Description

Dec. 23, 1952 R, w, BAILEY 2,622,972

GAS PRODUCER AND METHOD OF OPERATION Filed Nov. 26, 1946 .Ivwyentor-:

' Richard W- 561N656 WW a?) His Attorney Patented Dec. 23, 1952 'UNITED STATES PATENT OFFICE GAS PRODUCER AN Di'METHOD :JOF OPERATION Richard W. Bailey, Hale, England, assignor, .by

. .mesne assignments, to General Electric Gom- .pany, a corporation of New York vApplication" November 26, 1946,- Serial No. 712,413

-lnaGreat'Britain December 19, 1940 Section 1; Public Law 690, Aug-ustS, 1-946 "Patent expires December19, 1960 7 Claims.

I 1 This invention relates to gas producer and has for its object to provide a gas producer in which the gas'delivered' thereby is substantially free of tar and so requires no subsequent cleaning processto remove tar. The gas :producer according to theinvention issuitable 'forthe supply ofinternal combustion engines used on ships-for propulsion-or other purposes. It isespecially suitable in ship propulsion plant wherein the propulsion power is sharedby a gas engine'and' by a'steam prime mover. Into theheat cycle of the steam prime mover is transferred-the waste heat of the gas engine -and-conveniently--also some of theheat generatedin the gas producer.

Heat may be extractedfrom the latter *by cooling the delivered'producer gas down to a-tem- *perature suitable for itsuse in the'gasengine-and by water jacketing of the body of the producer or other surfaces thereof which become hot.

The invention is, however. applicable tmgas producers generally and the above applications ofthe gas producers according to the invention are referred toonlybyway of example.

My invention comprises both a-methodv and apparatus aswill be-pointed out-in the appended claims.

The accompanying-drawing is a vertical section diagrammatically illustrating a producer embodying my invention.

The invention relates specifically tot producers of the updraft type; that isto 'say'wherein' the' flow of air,'steam and gas is upwards throughthe producer body, while themovement ofthe' fuel therein undergoing gasification is. downwards. by gravity.

It is known that when a gas isadmitted to a of zones of different temperature in thefuel bed. Thus, at the top of the gas producer body. to where the coal or similar fuel is fed continuously or periodically there is a relatively cool upper zone, section or chamber wherein distillation of volatile matter principally occurs below which a red-hot zone wherein the main fuel is.-being. 59 features: (a) by leading fifl e i hodxouhe converted to carbon-monoxide gas. This ,;-zone merges or joins'with a.bright;red--or.;whitehot combustionzone at which there ismaxjrnum tem- -,perature, the temperature, fallingsaway belowuntilthe ash zone. atgthe base-of the producer is reached. .An upwardly flowing-stream of;,a ir; and steam passes through the. ash zone and; enters the combustion and gas-makingzones-above,

- while theash is graduallyextracted by means;of

.a revolving or other suitable :mechan c k rat means through which the steamqandair-mayme caused to enter the producerbody. 'lnsthe'afore- .said top zone the, coal becomes gradually heated to .a temperature suchthat a;substantia1:,part,at least of all the tar-laden, unboundggaseousgproducts are driven: off, leaving 1 carbonized; fuel; in the middle zone subjectedtothe: air,-,.steam.;.and

carbon-dioxide from combustion. coming upfrom beneath :and. converting the ..carbon' to. :carbonmonoxide: with the: simultaneous :generation. :of

hydrogen. 1 ThelOWer-part of thebottom or-combustion zone isincreasedintemperature upwards vbycombustion with the up-fiowing: air and. steam It has been alreadyproposed for the'removal of the tar from the low-temperature tar-laden degasification products of the fuel to lead them back to a part ofthej fuel bed in the producer body hot, enough to'efiectvcracking of the-tar. Producersvaccording to th proposal do not seem to have been successful presumab1y. f.0rfil he.reason that the flow ofsaid degasification products through one or more conduits and portsinto the required hot zone of the fuel bedcausessuchcooling of this zone vwholly, or, in .the separated gas flow paths therein that; tar-cracking. does, not properly take place, while the efiiciency.of.-.the producer is seriously aifectedbkreasonsof; such cooling.

The present invention removes, or; minimizes the defects just above mentioned bythe following or any combination of such heating means. or more steam jets may be provided in each conduit or conduits aforesaid, being adapted to be producer gas at a zone in the fuel bed where the tar-laden gaseous products have been distilled ofi from the fuel which is there high enough in temperature and being subjected action by the upflowing steam and air, (b) the tar-laden gaseous distillation products coming from the top of the fuel bed are caused to flow down through one or more conduits and ports into a part of the hot middle zone of the fuel bed, which part is above or otherwise spaced from the main gas lead-off place or zone specified in (a) such that the tar-cracked distillation products flow to said main lead-off zone, although part of said gaseous products may re-enter and flow upwards through the top part of the fuel bed, and (c) the one or more relatively small paths or regions of flow of said distillation products through said hot zone of the fuel bed is or are continuously moved or periodically changed so as substantially to prevent the aforesaid undesirable cooling or stagnation in the hot zone of the fuel while obtaining satisfactory cracking of the tar.

The admission of the distillation products to the hot zone of the fuel bed must, of course, ef-

\ fect undesirable cooling to a small extent in relation to the volume of fuel in the hot zone, namely in the one or more moving or changing paths of gas flow therein, and according to a subsidiary feature of the invention the effect of this cooling may be, and preferably is, made up by the 1 admission to said paths or regions of fuel after the passage of the cooling gaseous products therethrough, of air with or without steam whereby to effect re-heating of the fuel by chemical combustion.

Extraction of the gas from above the fuel bed and its delivery again to the producer may be ensured by means of a pump, fan or like means,

but is preferably effected by a steam jet pump or injector. The steam for operating such jet pump may be generated wholly or partly by heat obtained from the producer, for example by means of a jacket to the producer. 1 pose also may be delivered from the gas being delivered, or it may be obtained from any suitable external source, for example the steam generator associated with the steam prime mover Heat for this purof the ship propulsion system referred to above One used periodically to clear away and blow through the producer soot and other deposits formed at the surfaces of the conduit or conduits, or tending to block the passage at any place therein.

It will be seen that with the arrangement according to the invention, while all gas finally leaving the producer has undergone conditions in the producer which ensure freedom from tar, updraught conditions obtain throughout the fuel bed to a degree in relation to the gas delivery which may be controlled by the setting of the steam jet, pump or other means employed to ensure extraction of gas above the fuel bed.

For example, in carrying out the invention according to one arrangement a plurality of conduits taking gas from above the fuel bed as aforesaid may be provided, each conduit having its own delivery port to the fuel bed, these conduits being operated at intervals so as to change the path of the tar-laden gas through an always hot part of the fuel bed.

In another arrangement there may be a conduit, preferably water-cooled, passing down axially from thetop of the producer into the fuel 4 bed and delivering the tar-laden gas through an opening or openings at the side of the conduit. By rotation of this conduit the point or points of delivery of the gas is continuously changed in relation to the fuel bed.

In a modification of the arrangement just above indicated, permitting the conduit to be fixed in position, the conduit is provided with two or a ring of delivery ports around its circumference and a rotating cover or valve is provided to restrict flow of the tar-laden gas at any time to one or some of the ports, and whereby the tar-laden gas is delivered in a continuously changing radial direction with respect to the axis of the producer and conduit.

The use of a plurality of conduits each taking gas from above the fuel bed, passing outside the producer body, then downwards and delivering the gas to the producer at a lower level constitutes one form of the producer according to the invention.

The tar-free gas leaving the producer may do so at one or more apertures or an elongated aperture in the side wall of the producer. In one construction the wall of the producer is made in two parts or sections, an upper cylindrical section and a lower coaxial cylindrical section with an annular gap between the two sections through which the tar-free gas leaves the producer, the lower section being sufficiently larger in diameter than the upper section and embracing or overlapping the end of the upper section so as to create the annular gap between the two sections.

The producer body may be water-cooled or jacketed and the heat taken up by the jackets may be utilized for steam generation. The steam so generated may be employed partly or wholly in operating the producer both in mixing with the air admitted to the fuel and in operating the aforesaid conduit jet pumps or injectors.

The aforesaid conduit, or each of the said conduits, is preferably connected at one end with the upper part of the producer body and with the lower part of the body at its lower end and contains at its upper end an injector nozzle for steam and air.

Arrangement may be made for the inlet of the respective conduits to be closed off by a valve mounted and sliding on the steam nozzle, the latter conveniently being arranged to point down the section of the conduit between gas inlet' and delivery ports of the latter.

Where there are several fixed conduits, each i is brought into operation by opening said inlet valve and supplying steam to the nozzle, and after a suitable interval said inlet valve is closed and the steam valve controlling said nozzle closed, and the next conduit similarly used, and so on. Both the opening and the closing of the inlet and steam valve are preferably performed mechanically and carried out at each of the conduits in succession. The valve gear may conveniently be connected with the mechanism for rotating the grate or theair and steam inlet head of the producer in cases where such ardiameter. jacketsp'ace wherein water maybe heated or steam may'begenerated. Extending from the annular space 3b 'vertically through the jacket space are the producer gas outlet tubes 4 and alternating with the gas'tubes 4.

games tea-fame are usedjthe latterrrlay'eonveni'ently be "said intervals, or continuously. Preferably the admitted air is caused to flow in from the atmosphereunder' reduced pressure existing at the conduit. Air may also be admitted to'the' conduit or conduits at intervals for the purpose of burning away soot deposits.

The accompanying drawing refers to the main part of the gas producer which comprises the outer wall 2 and the inner wall parts 3 and 3a, the latter at 3b downwards being of increased The inner and outer walls provide a the larger preheater or superheater flue tubes 5 The tubes 3 and 5 lead to the gas belt 3 having the gas delivery outlet 1, the belt 6 surrounding the annular space 8 lined with refractory material 3. For convenience of description the space 8 will be hereinafter called the tarry gas space: it receives the aforesaid tar-laden gaseous distillation products rising from the top surface indicated at I of the fuel bed within the body walls 3 and 3a. Coal or similar fuel is admitted in per se known gas-tight manner through the illustrated aperture II in the producer lid or cover l2, which maybe rotated for ensuring an even distribution of fuel supply to the producer body. In the flue tubes are disposed the pre-heater or superheater tubes connected at their respective ends with headers l4 and I5. I

Beneath the main part I of the producer body is a conical part It which may also provide a jacket spaceand which at its narrow lower end has the continuously rotating grate driven by a worm gear Hat. The foundation of the gas producer is indicated at E8 and has within it the inlet members IQ for the main supply of steam and air for therfuel bed in the producer body, the mixture passing upwards thereto through the grate and ash zone indicated at 23.

Passing axially through the producer body and through the inlet member I9 by the seal 25 is the conduit having the inner wall 2| and outer wall 22 providing a water jacket space wherein steam may be generated. The water level in this jacket space, indicated at 23, may be maintained by a ballcock or the equivalent, the water entering the space at the bottom of the conduit through the non-rotating member 24. The conduit 2| is fixed to the grate I1 and continuously rotates therewith.

The conduit 2|, which may be lined with refractory material, is divided at the appropriate place in relation to the fuel bed by a member 26 having a partition 21 above which is a single port 28 (or two diametrically opposite ports) registering with a downwardly slopin port (or two respective ports) in the conduit 2|, as shown. A short distance beneath the partition 27 the member 26 has a port 23 (or two diametrically opposite ports) registering with a downwardly sloping port (or ports) in the conduit 2|, as shown.

Furthermore, the conduit 2| has at its top end one (or more) ports 30 communicating with the tarry gas space 8, and has at its bottom end one (or more) ports 3| communicating with the steam and air supply space in inlet members I9.

Suitably disposed b'elow'the upper"port--('or ports) 30 is'the'injector nozzle 32 for entraining the tar-laden distillation products rising from the top of the fuel bedinto the space 8,

, into and down the conduit 2| and thence through the port 28 into the hot zone of the'fuel bed generally indicated at 33. The injector'nozzle 32 is shown as attached to a member 34 which may be moved vertically so asto constitute in conjunction with the port 30 a valve which may be closed such as when starting up the producer. The member 34 has a tubular stem 35, having ports (not shown) by'which the steam and; air

may be supplied to the nozzle 32 through the pipes 36 and 3? and fixed sleeve 38 through which the stem 35 is adapted to slide.

Extending from the steam space above: the water level 23 in the jacket space between'the walls of the conduit 2| is shown a vertical tube 39 (or tubes) terminating in'the conduit port which registers with the part 29 in the partition member 25 for augmenting if desired'the steam (and air) normally supplied from the inlet members l3 through the lower part of the conduit 2| to reheat the hot zone 33 of the fuel bed following the partial cooling thereof by the tar-laden distilled products which enter the hot zone through the port 28.

It will be appreciated that beneath the hot zone generally indicated at 33 the fuel is substantially fully carbonized (degasified and tarfree) and that the main supply Of steam and air from the inlet members I3 passes generally as indicated by the arrow-headed dotted lines 43 to the region 3?) of the producer body, generating on the way the main body of producer gas which passes up the tubes l and 5 to the gas delivery belt 3.

The tar-laden gaseous distillation products coming from the fuel bed surface Hi into'the annular space 8 are drawn through the ports 30 into the upper end of the conduit 2| and 'flow' down therein and emerge through the port 28 into the hot zone 33 of the fuel bed. Some of 'these gaseous products flow to the space 31), having been freed of tar on the way thereto,'as indicated at 4 while some of this gas flows upwards'as indicated at 1-2, joining the .products of distillation and hastening the latter process.

The air and steam emerging from the conduit p'ort 29 partly flows as indicated at 43 towards the gas collecting 'space at 3b, 'and partly 'upwards as indicated at M, again to hasten the distillation process.

The hot gas from the outlet I may be passed through a heat-exchanger for preheating air or steam or both, used in the gas producer or elsewhere, which oxidizing gas may be superheated in the tubes I3 located in the fire tubes 5. The body jacket 2, 33a may have steam generated therein at any desired pressure for any convenient use.

Instead of the steam being delivered from the space above the water level 23 in the conduit jacket 2|, 22 to the port 29, it may be delivered to beneath the grate Air only may when required be admitted to the nozzle 32 for the purpose of burning away deposits of carbon in the conduit 2|.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of regulating the flow and generation of producer gas which consists in subjecting a bed of coal to a current of oxidizing gas to cause combustion and heating thereof, collecting producer gas substantially free of distillation products from said bed at the hot middle zone where the tar-laden distillation products have been distilled off from the fuel, conducting the circulation of the tar-laden gaseous distillation products coming from the top of said bed through one or more paths into a part of said hot middle zone of said bed, which part is spaced from the main gas collecting zone so that a substantial portion of the tar-cracked distillation products flows to said main collecting zone while the remainder flows tothe cool upper portion of the fuel bed, periodically changing the part of said hot middle zone of said bed subject to the flow of said distillation products so as substantially to prevent undesired cooling of said hot middle zone while obtaining satisfactory cracking of the tar.

2. The method of regulating the flow and generation of producer gas which consists in subjecting a bed of coal to a current of oxidizing gas whereby combustion results, collecting producer gas from said bed at a hot middle zone in the bed where the tar-laden products have been distilled off from the fuel, causing a recirculation of the tar-laden distillation products coming from the top of the bed through one or more paths into a part of said hot middle zone of the bed which part is spaced from the main gas collectillg zone so that a substantial portion of the tarcracked distillation products flows to said main collecting zone, periodically changing the part of said hot zone being subject to said recirculation and periodically admitting oxidizing gas to the portion of said bed of coal which has been cooled by the passage there-through of tar-laden distillation products thereby effecting combustion and consequent reheating of the fuel which is adjacent the path of flow of tar-laden gas.

3. A gas producer comprising a grate means for supporting a fuel bed, walls rising upwardly from i said grate means, said grate means and walls defining a fuel chamber which is adapted to contain said fuel bed, an inlet for an oxidizing gas below said grate means, an outlet for product gases located in the side wall of said gas producer between the top and bottom of said fuel chamber, a hollow member extending down from above said fuel chamber into said fuel chamber, an opening in said hollow member above said fuel chamber,

and an opening in said hollow member into said fuel chamber at a point above said product gas outlet, said openings and said hollow member forming a passage for the movement of distillation gases from above the fuel chamber down into the intense combustion zone of said fuel chamber, said hollow member constructed so as to be rotated in order to avoid cooling said intense combustion zone, and means for effecting said rotation.

4. A gas producer as claimed in claim 3 having in addition conduit means within said hollow member for introducing oxidizing gas to the regions in the fuel chamber at a point slightly above, and disposed substantially horizontally from, the product gas outlet.

5. A gas producer as claimed in claim 3 wherein said hollow member is centrally located with respect to said fuel bed.

6. A gas producer as claimed in claim 3 having a steam injector provided in said hollow member.

7. A gas producer as claimed in claim 3 having in addition conduit means within said hollow member for supplying oxidizing g s to the regions in the fuel chamber at a point slightly above, and disposed substantially horizontally from, the product gas outlet, said conduit means being provided with one or more ports.

RICHARD W. BAILEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 594,483 Mitchell et a1 Nov. 30, 1897 650,698 Whitfield May 29, 1900 732,950 Leclere July 7, 1903 776,947 Schmidt Dec. 6, 1904 786,474 Whitfield Apr. 4, 1905 827,862 Gerdes Aug. 7, 1906 836,054 Schmidt Nov. 13, 1906 846,357 smith Mar. 5, 1907 972,864 Jewett Oct. 18, 1910 1,116,216 Berry Nov. 3, 1914 1,125,919 Wallman Jan. 19, 1915 1,175,844 Versen Mar. 14, 1916 1,175,845 Versen Mar. 14, 1916 1,177,584 Wallman Mar. 28, 1916 FOREIGN PATENTS Number Country Date 579,416 France Aug. 1, 1924

Claims (1)

1. 3. A GAS PRODUCER COMPRISING A GRATE MEANS FOR SUPPORTING A FUEL BED, WALLS RISING UPWARDLY FROM SAID GRATE MEANS, SAID GRATE MEANS AND WALLS DEFINING A FUEL CHAMBER WHICH IS ADAPTED TO CONTAIN SAID FUEL BED, AN INLET OF AN OXIDIZING GAS BELOW SAID GRATE MEANS, AN OUTLET FOR PRODUCT GASES LOCATED IN THE SIDE WALL OF SAID GAS PRODUCER BETWEEN THE TOP AND BOTTOM OF SAID FUEL CHAMBER, A HOLLOW MEMBER EXTENDING DOWN FROM ABOVE SAID FUEL CHAMBER INTO SAID FUEL CHAMBER, AN OPENING IN SAID HOLLOW MEMBER ABOVE SAID FUEL CHAMBER, AND AN OPENING IN SAID HOLLOW MEMBER INTO SAID FUEL CHAMBER AT A POINT ABOVE SAID PRODUCT GAS OUTLET, SAID OPENINGS AND SAID HOLLOW MEMBER FORMING A PASSAGE FOR THE MOVEMENT OF DISTILLATION GASES FROM ABOVE THE FUEL CHAMBER DOWN INTO THE INTENSE COMBUSTION ZONE OF SAID FUEL CHAMBER, SAID HOLLOW MEMBER CONSTRUCTED SO AS TO BE ROTATED IN ORDER TO AVOID COOLING SAID INTENSE COMBUSTION ZONE, AND MEANS FOR EFFECTING SAID ROTATION.

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