US1780759A - Method for producing water gas - Google Patents

Description

Nov. 4, 1930. SJ.mm-FE ,78 7 9 METHOD FOR PRODUCING WATER GAS Filed Sept. 21, 192 5 2 Sheets-Sheet 1 A-TTORNE Y Nov. 4, 1930. s. .1. MCAULIFFE ,759

METHOD FOR snonucme WATER (ms Fild Sept. 2'1, 1921' 2 Sheets-Sheet 2.

h I I F e V M" ,ZVMQM ATTORNEY:

l NVENTOR Patented Nov. 4, 1930 l UNITED STATES PATENT OFFICE v SYDNEY JOHN MCAULIEFE, DIE SYDNEY, NEW SOUTH WALES, AUSTRALIA, ASSIGNOR,

BY MESNEASSIGNMENTS, T FULLER LEI-IIGH COMPANY, A CORPORATION-Q1? DELA- WARE METHOD FOR PRODUCING WATER GAS Application filed September 21, 1921. Serial No. 502,141.

This invention relates to a method for producing water gas from pulverized carbonaceous material, usually coal.

I Methods of producing gas from hard coal by burning with an insufficient supply of oxygen to form C0 are well known and-many different types of apparatus have been devised for this purpose. Following the same principle of operation, pulverized coal has been employed for producing gas by blasting the coal into a chamber where it'is burned to form CO which is then reduced to CO by admitting an additional supply of coal.

In contradistinction to these methods, the invention provides primarily a method of obtaining gas from pulverized carbonaceous material, particularly pulverized coal, by destructive distillation of the material while the particles are in a state of suspension resulting in the complete gasification of the material. Where the destructive distillation is carried on in the presenceof steam, not only is the gas resulting from distillation produced, but the steam'is broken up into hy-' drogen and oxygen, the latter uniting with free carbon to form carbon monoxide, and the hydrogen escaping as free hydrogen or in the form of hydrocarbons. The gas produced may be enriched by the addition of heavy hydrocarbonssuch as oil or tar.

Preferably the method described of gasifying carbonaceous material is carried on in an externally heated retort alone, or in the presence of steam or hydrocarbon enriching agents, or both. 1 The material should. be injected into the retort in such manneras to cause the particles of material to be separated in suspension within the retort in the form ofa sheet of great expanse. One Way to accomplish this result is by feeding the material into a blast of steam together with oil or tar, where an enriching agent is employed, in which case the atomized steam and oil or tar combine with the particles of material to 7 heat radiated from the walls thereof will im-- mediately penetrate the material upon its entrance into the retort thus causing the destructive distillation to begin at once and to This will readily be accomplished tial height and the material is-introduced near the top thereof. Also under these conltions the. atomized steam Will at once break up 1nto hydrogen and oxygen and the latter .will unite with free or fixed carbon'to form Water gas.

The gas produced issubjected to a cooling and washing process in the usual manner wherein the solid and liquid matter contained in the gaseous constituents will be removed.

and the tar returned to the retort for permanent fixatlon as an enriching gas.

In carrying out the method and variations thereof above described, one form of apparatus employed is a type having aretort which is heated by a pulverized fuel fired furnace. This type of apparatus includes a retort, into which the pulverized material to be gasified is injected, a fuel chamber and a flue for conducting hot gases to the retort, the fuel chamber preferably being located beneath the retort and having a plurality of vertically extending flues for conducting the hot gases therefrom to externally heat the walls of the retort. Irrespective of the particular form or arrangement of the parts of the apparatus for heating the retort, the means for injecting the materialinto the retort may comprise a conveyor, a nozzle, and means for inJecting steam together with tar or oil, or both, through the nozzle by which the material is carried from the conveyor by injector action of the steam or mixture of latter into the retort in the. form of a sheet.

Another-form of apparatus is one which, instead of using pulverized fuel as a source of-heat, as in the above example, is designed for employing a portion of the gas produced by the apparatus for heating the retort thereof. In this construction, the retort for gasifying coal has adjacent its enclosing walls a plurality of fines for externally heating vthe retort, and these flues are provided with means for employing a portion of the gas produced. in the retort for heating the latter. Preferably the flues are arranged on opposite sides of the retort, each'flue con- 'sisting' of a pair of passage-ways, one being' a gas up-t'ake passage-way and the other a gas down-take passage-way, and a burner is provided for each of the fines positioned in the gas up-take passage-way. These burners have connection with suitable means for supplying thereto a portion of the gas produced y the apparatus. 1 For a better understanding of the details of the invention reference may be had to the accompanyingdrawings illustrating one form of apparatus for practicing the method of the invention. 1

In the drawings Fig. 1 is a sectional view in elevation of a gas generating apparatus for pulverized carbonaceous material in which pulverized fuel is employed for heating the retort whereside walls 9 enclosing an inner chamber in which are the retort10 and the combustion chamber 11 separated by an arch 12, The. retort 10 is a long and narrow chamber situated inthe upper part of the. apparatus and extending from end toend thereof, being formed by sidewalls 1'3 and upper and'lower arches 14 and 12 respectively. Each of the end enclosing walls 6 has near the to wall 7 a port 15 opening into an inwardly aring recess 16. Fitting in the port 15' is a nozzle 17 disposed substantially horizontally as shown and having a Y-connection with a steam pipe 18 and a pipe 19 through which vaporized tar is conducted. Also opening into the recess 16 is the discharge end of an inclined screw conveyor 20 for conveying the pulverized carbonaceous material from a bin (not shown) to the retort. .The top' wall 7 is provided with a series of gas outlet openings 21 through which the. gas produced in the retort 10 is conducted to pipe lines for ultimate discharge after the'washing treatment to a holder.

Situated beneath the retort 10 is a combustion chamber 11 designed for burning pulverized fuel which is injected into the combustion chamber by means of an induction burner 22. Situated between the side walls 13 of the retort and the walls 9 of the apparatus is a pluralitv of vertical fiues 23 communicating at one end with the combustion chamber 11. through flaring openings 24 in the arch 12, and at the other end with p with means for leading out waste gases.

Slidably mountedineach of the side walls 9 are dampers 26, one for each flue, which may be regulated to closeany or all of the fines to the passage of ases, the dampers in their. closed position tting into recesses 27 in the sidewalls 13 of the retort.

.YVith the arrangementdescribed it will be seen that-the retort l0 confines the pulverized coal and steam in the form of a thin, vertical sheet of great expanse and heat is applied to the sheet through the opposite side walls 13 and through the bottom wall 12. By this method of application of the heat all of the coal particles introduced into the chamber are heated substantially uniformly and the. insulating. effect present inretorts in which the mass being heated is of considerable thickness is largely eliminated. With. the present arrangement the heat is applied over a large area and the mass of material being heated is relatively thllliiSO that the heat reaches the particles throughout the mass. The heat applied at the lower edge of the retort insures the complete-distillation-of particles which may settle on' the lower wall.

It will be noted that the pulverized coal, steam and enriching agent, when-the latter is used, are all introduced substantially horizontally into the high narrow chamber near the top thereof and beneficial results are de rived from this manner of feeding. One of the advantages obtained is that the stream of steam and coal entering the chamber at a substantial velocity through the recess 16 exvs I pands when it enters'the chamber with a resultant decrease in velocity. The stream spreads so as to fill evenly the space defined by the hot side walls, and there is a change in direction in the flow of the particles which float gently downwardly remaining in suspension for a period of time sufficient to permit substantial completion of the distillation and chemical reactions which occur. The withdrawal of the as at the top insures a flow of gas and soli s in opposite directions through -the chamber, the solids slowly descending to the hot floor where the process may be finished as to such particles as have not taken their full part in the reactions while insuspension: The upward flow of the gas assists in suspending the solid particles in the manner described, and it is preferable to adjust the rate of admission to the progress of the reaction sothat gasification of the par-, ticles is substantially complete while they are in suspension.

The operation of the apparatus thus described is as follows: The pulverized-matewater gas thus produced .ports 21 and into pipe lines through a washer rial to be gasified, as for instance pulverized coal, is conducted to the retort chamber 10 from a bin by means of the screw conveyor 20, the material being ledto a point inthe recess 16 adjacent the discharge end of the nozzle. The mixture of superheated steam conducted through the pipe 18 and vaporized tar or oil, which, is preferably preheated and conducted through the pipe 19, is discharged from the nozzle 15 at high velocity producing an injector action and drawing the pulverized material from the end flights of the screw conveyor near its discharged end by suction, the blast of steam and vaporized tar-then propelling the material into the retort in the form of a sheet of great expanse defined by the closely spaced walls- 13 of large area. Since the discharging means for coal and the mixture of steam and tar -or oil are situated in the upper part of the retort 10 near the top wall 7, the sheet of suspended materlal 1ntermixed with steam and atomized hydrocarbons slowly descends by gravity toward the bottom of the chamber. Immediately the material is injected into the retort, and continuously during its descent, the suspendedparticles are subjected to an intense heat radiated from the externally heated walls of the retort chamber so that destructive distillation of the material begins at the instant of its introduction into the chamber, proceedsas the material descends and is substantially completed before it reaches the bottom of the retort. Where pulverized coal is employed, the destructive distillation results in coal gas, the volatile constituents of the coal being separated from thefixed carbon content. The walls of the retort chamber are heated to a temperature" of 2800 to 3090 F. at'which temperature the destructive distillation is rapidly completed and the steam substantially dissociated in the presence of 1ncandescent carbon into hydrogen and oxygen, the latter combining with the fixed or free carbon of the coal to produce carbon monoxide, and the hydrogen escaping as free hydrogen or in the form of hydrocarbons. The passes out of the to the gas holders The tar recovered during the cooling and washing s returned to the supply system and again in ected'iii to the retort through the pipe 19. Upon 1t; second entrance into the retort the tar is broken up and gasified, and serves to enrich the gas, the enrichment being sufficien't to bring-the gas up to the usual calorific standard. Additional enrichment may, of course, be produced by admitting oil with the tar.

Should it prove necessary or desirable to provide means for the removal of ash or other ungasified substances which might collect upon the bottom of the retort chamber 10, a clean-out door or gate 29 at either or both ends as shown in Figs. 1 and 2 may be provided.

The combustion chamber 11 is of large dimensions as is customary in pulverized fuelfired furnaces. The hot gases from the combustion chamber pass upwardly through the flues 23 adjacent the side walls 13 of the retort and through the waste gas flues 25, and thus the enclosing walls 12 and 13 of the retort are, at their outer surfaces, in direct contact with the hot gases of combustion from the chamber 11, the wall or arch 12 separating the combustion chamber from the retort. The combustion chamber 11 is provided with a cleanout door 28 for the purpose of removing ash and non-combustible material de- I posited on the bottom of the chamber.

I claim:

1. The method of producing water gas, which comprises maintaining a quantity of pulverized coal and steam in intimate mixture in suspension in the form of a relatively thin, vertical sheet of great'expanse by continuously supplying pulverized coal and steam to the sheet near the top'thereof, and distilling the coal while in suspension and substantially dissociating the steam into its componentelements in the presence of incandescent particles of the coal by the application of heat to both faces and along the bottom edge of the sheet.

2. The method of which comprises maintaining a quantity of pulverized coal andsteam in intimate mixture in suspension in. the form of a relatively thin vertical sheet of great expanseb'y continuously supplying pulverizedcoal and steam to producing water gas,

the sheet near the top thereof, applying heat to the opposite faces and the bottomedge of the sheet in amounts sufiicient to render the coal incandescent and to efi'ect substantial dissociation of the steam into its component elements as well as the destructive distillation of the coal while the particles thereof are in suspension, and continuously injecting an enriching material into the mixture of coal and steam in suspension.

3. The method of producing water gas, which comprises continuously introducing pulverized carbonaceous material and steam in a substantially horizontal direction into a high, narrow, long vertically disposed chamber near the top thereof, the solid material and steam forming a relatively thin-vertical sheet within the chamber through which the particles of the materialdescend slowly by liq gravity, heating the, sheet of material and and steam substantially horizontally into a high, narrow, long chamber having Walls of great expanse near the top of said chamber 'to form a relatively thin vertical sheet of said descend by gravity, the particles losing vesolid material and steam within the chamber through which the solid particles slowly :locity shortly after they enter the chamber and changing direction before their descent, and supplying heat to both faces of the sheet suflicient to effect the Water gas react-ion.

5. Themethod of producing water gas, which comprises continuously mtroducing pulverlzed carbonaceous material and steam ina substantially horizontal direction into a high, narrow, long, vertically disposed chamber, near the top thereof, heating the walls of the chamber to a temperature of'at least 2800'F., the solid material and the steam forming a relatively thin sheet within the chamber, through which the particles of the material descend slowly by gravity and thereby heating the sheet of material and steam to effect the Water gas reaction.

6. The method of producing water gas, which comprises continuously introducing Dpulverized fuel and steam in a substantially orizontal direction into a high, narrow, long, vertically disposed chamber, near the top thereof, the .solid material and the steam fl-Orming a relatively thin sheet within the chamber through which the' particles of the material descend slowly by gravity, and heating the sheet of material and steam to a temperature of approximately 2800 F. to 3000- F. to eifect the Water-gas reaction.

7. The method of producing water gas which comprises continuously introducing pulverized fuel and steam in a substantially horizontal direction into a high, narrow, long, vertically disposed chamber, near the top-thereof, the solid material and the steam forming a relatively thin sheet Within the chamber through which the particles of the material descend slowlyby gravity,and heating the sheet of material and steam to a temperature suflicient to effect a substantial water gas reaction and producing essentially carbon monoxide and hydrogen.

In testimony whereof I afiix my signature.

1 SYDNEY JOHN MQAULIFF E.

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