FI56695C - FOERFARANDE FOER FRAMSTAELLNING AV GAS FRAON KOL - Google Patents

Abstract

1483135 Wet separating KAMYR Inc 30 Jan 1975 [31 Jan 1974 20 Jan 1975] 4102/75 Heading B2H [Also in Division C5] A method of delivering to a gasifier vessel 10, Fig. 1, coal, oil shale or lignite of particle sizes falling within a predetermined range of sizes (free of fines), the lower limit of which is approximately “" nominal diameter e.g. in the range “"-2" nominal diameters involves the establishment of a continuous flow of liquid (water or oil and light tar) along a first continuous flow path 20 at low (atmospheric) pressure, feeding coal or like particles from a hopper 42 downwardly through the free surface of the liquid in the chamber 50 forming part of the first flow path, transferring coal particles of the required size in incremental volumes of liquid into a second continuous flow path of liquid 26 at elevated pressure by use of a sluicing aparatus 30 (described below) provided with a screen 92 of the requisite size, and conveying the particles in the liquid of the second flow path by line 70 to a mechanical separator 32 mounted at the inlet 12 to the gasifier vessel 10. In the separator the particles are moved by a screw conveyor 96 upwardly through the free surface of the liquid, thereby falling into the inlet 12. Liquid and entrained fines passing through a screen 98 surrounding the screw conveyor, flow along line 102 to a centrifuge 36 where such fines are removed. The purified liquid is pumped back to the sluicing apparatus. Entrained fines in the first liquid flow are similarly removed by centrifuge 34. The apparatus includes provision for counteracting the net loss of liquid, particularly from the second flow path to the first. The sluicing apparatus, Figs. 2 to 4, consists of a pocketed wheel 72, see Fig. 4, mounted for rotation within a liner 76 having ports 78, 80, 82 and 84 which register with the inlets 52, 64 and outlets 58, 68 to the apparatus, in the first and second flow paths, respectively, see Fig. 2. During filling of a pocket 74 in the rotating wheel 72, fine coal particles are drawn through the peripheral slots in the screen 92. The liner may be provided with peripherally projecting grooves 94 acting as flow breakers adjacent the port openings 80 and 84 of the second flow path. The pocketed wheel 72 may be either cylindrical or tapered with the wheel diameter increasing in the direction of a clearance adjusting hand wheel 88, Fig. 3.

Description

5fcSF * l m ni \ ADVERTISEMENT _ _ „tB] (11) UTLAGGNI NGSSKRI FT 56695 • S / S C (45) Patent granted 10 03 1930

Patent pending (51) Kv.llc. * / Lnt.CI. 'C 10 J 3/06 FINLAND — FINLAND (21) Patenttllwl »imM — Patentantdknlng 750251 (22) Hakemlspilvi — Ansdkningtdag · 30.01.75 (23) Alkuptlvi — Giltlghetsdag 30.01.75 (41) Tullut | ulkiMksl — Bllvlt offentllj 01.08.75

National Board of Patents and Registration »... at-« h regiit.nt) rr «l (« n <«> 30.11.79 (32) (33) (31) Privilege requested — Begird prloritet 31 ·· 01.7 ^ 20.01.75 USA (US) U38273, 5U2U07 (71) Kamyr, Inc., Glens Falls, New York, USA (US) (72) Erwin Duane Funk, Glens Falls, New York, Michael Ignacy Sherman,

Glens Falls, New York, USA (US) (7 * 0 Oy Kolster Ah (5¾) Method for producing gas »from coal - Förfarande för framställ-Ning av gas fr & n koi

The invention relates to the production of gas from a gas generating agent such as coal, oil shale, lignite, etc., and more particularly to a gasification process and apparatus in which gas generating pieces are continuously fed to a high pressure gasification zone or vessel.

^ U.S. A December 1972 report to the Interior Department Office of Coal Research, entitled "Evaluation of Coal-Casification Technology," concluded that the natural gas situation at the time was critical enough to justify making the greatest effort to develop the best and most economical methods to produce pipeline-grade gas from coal as soon as possible. The "ad hoc industrial panel" committee that drafted the report noted that at the time of the report, the Lurg solid-state coal gasifier was the only coal gasification unit ready for industrial use. The flow diagram of the Lurg solid-state carbon gasifier is presented in the Industrial Press. Figures 3-69 in the Gas Engineer's Handbook, Part C 10 J 3/1 * 6 2 56695 1969, published by Inc., on pages 3/106 · For clarification of the background to this explanation, reference is made to Chapter 9 of the Gas Engineer's Handbook, pages 3 / IOO-3 / III together with the above-mentioned assessment of carbon gasification.

The above-mentioned Committee's analysis of the Lurgi solid bed process is presented in the report on page 37 as follows: In the United States, these methods of combustion were abandoned 30-50 years ago when these methods were used in high-velocity combustion systems. This is why the Committee recommends extensive research into a number of high-pressure coal gases to test processes in order to determine as soon as possible which or two processes are the most technologically and economically advantageous for gasification plants ".

Thus, all other gasification processes evaluated by the evaluation committee include the supply of coal dust and the use of coal dust in gasification. In at least one of these processes, the coal dust or powder is fed as a slurry. However, when evaluating this process, it is considered a disadvantage that the advantages of sludge feed are offset to some extent by the preparation of the sludge, the recovery of the liquid used in the sludge, especially the oil, and the heat required in the recovery stage.

The features of the method according to the invention appear from the appended claim 1. The present invention makes it possible to take advantage of the experience gained so far in the use of fixed bed gasification and to eliminate the inherent disadvantages mentioned by the above-mentioned committee without having to develop carbon dust processes for commercial utilization. According to the principles of the present invention, this object is achieved by first mixing a liquid into the lignite feed to form a slurry and treating and transporting the feed in the form of a slurry. Although the supply of coal dust as a slurry is known, the present method eliminates, in accordance with the principles of the invention, precisely those disadvantages which the Committee found to exist in the slurrying of coal dust. Applicants have stated that the energy requirement for separating coal dust from a liquid medium is primarily related to the separation of the liquid adhering to the surface of the pieces rather than the liquid in their intermediate spaces. Applicants have stated that this energy requirement is significantly reduced when carbon is in lump form instead of dust or powder form due to the substantially lower surface area / volume ratio of solids. In the present system, the pieces are separated from the amount of liquid filling their spaces simply by passing the pieces up through the free surface of the liquid, which communicates with the pressure in the inlet line of the gasification zone or vessel and forms an effective barrier. The upward movement can be suitably achieved by rotating a simple screw conveyor. Water or other liquid adhering to the surface of the pieces is removed using heat in the gasification zone or vessel, but since the ratio of surface area to volume is relatively small compared to a very large ratio for coal dust, the heat demand to remove surface water does not cause significant energy loss. The present system also saves the energy required for pulverization.

It is not in accordance with the present invention that slurry is used, nor that the pieces of carbon are ultimately fed to a pressurized environment by passing them upwardly through the free surface of the fluid that communicates with that pressurized environment. In addition, the successful use of a continuous supply of lignite to a pressurized environment in accordance with the principles of the invention requires that the slurry be pumped in such a way that the pump acts only on the liquid component. This is accomplished in the invention by forming a closed low-pressure fluid circuit that also has a fluid reservoir whose free surface communicates with pressure conditions that are lower than the pressure conditions prevailing in the inlet line of the carburetor (gas generator). This pressure preferably corresponds to atmospheric pressure, thus allowing the pieces of carbon to be simply fed into the low-pressure liquid as the carbon moves under its own weight through the free surface. As the pieces travel with the fluid in the low pressure circuit, successive amounts of carbon and transport fluid are removed from the connection of the first circuit and connected to the second circuit at a location between the pumping station and the carburetor feed station.

The primary function of the second high pressure circuit in the present system is to recycle and does not pressurize the liquid and the pieces from atmospheric pressure to the pressure at the carburetor inlet 66695 as the pumps used to supply powder sludge previously known do. The pressure of the liquid in the second circuit of the present invention is maintained, as stated above, by connecting the pressure of the carburetor inlet pipe to the free surface in the circuit. The pump is primarily arranged for recycling and thus for transporting coal pieces.

Another object of the present invention is to provide a combination of device components for carrying out the above-mentioned operations, in which the individual device components are known per se.

These and other objects of the present invention will become apparent from the following detailed description and appended claims.

In order that the invention may be better understood, an illustrative embodiment is shown in the accompanying drawings, in which Fig. 1 is a flow chart showing the operating steps of the present method and an apparatus according to the invention for performing the operating steps of the method; Fig. 2 is an enlarged fragmentary sectional view of the transfer device shown in Fig. 1 with associated accessories; Figure 3 is a perspective view of the transfer device; Fig. 4 is an exploded perspective view showing some parts of the transfer device shown in Fig. 3; and Fig. 3 is a flow chart showing a simplified version of the method operating steps and an apparatus for performing the method steps according to the principles of the present invention.

Fig. 1 of the drawings shows a flow diagram illustrating the principles of the method of the invention for the continuous supply of carbon to a continuous, pressurized solid bed type carbon gasifier, the so-called Kaa-sugeneraattoriin. In the drawings, the carbon gasification vessel is indicated by 10, and the carburetor is, as stated above, of the conventional continuous solid bed type with an inlet pressure of 21 kp / cm and higher to the inlet pipe 12 at the top of the vessel to which carbon is fed according to the principles of the present invention. The heated gas which converts the coal to gas is fed to the gas tank 10 from an inlet pipe 14 near this bottom. · The ash and solid carbon residue formed in the gas tank 10 are removed from the bottom opening 16. The gas produced in the gas vessel 10 is continuously removed from the gas outlet 18 next to the top. 10 may be of any conventional type in structure and operation in which the gasification process is carried out continuously under pressure in such a way that fine pieces of carbon (nominal diameter e.g. about 3 mm and smaller) in the gasifier vessel 10 adversely affect the process.

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The present method of feeding coal, oil shale or other gas generating agent to the gasifier vessel 10 includes providing a continuous flow of liquid to the first flow circuit, indicated generally at 20 in Figure 1. The liquid may be any suitable liquid such as water or the like. will be explained in more detail below. The first flow circuit 20 is made circulating by connecting to it a pump 22, the function of which is to create and maintain the flow in the circuit. After the pumping station formed by the pump 22, in the downstream direction, there is a carbon supply station, in which carbon pieces of a certain size range (nominal diameter, e.g. from about 6 mm to about 50 mm) are fed into the liquid. The lower and upper limits of the preferred size range just exemplified are approximate and may vary, especially for an approximate upper limit, which may extend well above the approximate value of 50 mm exemplified. The variation from the lower limit downwards is more critical in that it should reach a value that includes strong pieces of a size that adversely affects the gasification process, as already mentioned above.

The size range is primarily determined by the needs of the gasification process itself, as the feed system according to the invention is capable of handling pieces of all sizes. Considering the properties of the feed system alone, it is advantageous to raise the lower limit to increase the surface area / volume ratio of the pieces and thus reduce the thermal energy required to remove the liquid adhering to the surface and lower the upper limit to reduce the wear effect on the device.

The device for supplying carbon to the circuit at the feed station is shown in its entirety as 24. The carbon fed to the liquid in the feed station enters and flows with the first flow circuit 20 to a transfer station where successive amounts of carbon entrained in the liquid are removed from the first flow circuit. carbon fragments smaller than the above-mentioned specified size range are allowed to continue at their current level in the first flow circuit.

The present method also includes providing a continuous flow of liquid in the second flow circuit at an energy level higher than the energy level of the first flow circuit. The high energy flow circuit is generally designated 26 in Figure 1. As shown, the second flow circuit is made circulating by placing a pump 28 at the pumping station of the circuit to provide and maintain flow in this circuit.

At the transfer station of the second flow circuit, which is located downstream of the pumping station of this circuit, successive amounts of carbon pieces and transport fluid are removed from the fluid of the first flow circuit and combined

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to another flow circuit. The operations of removing successive amounts of carbon in the liquid from the fluid of the first flow circuit and connecting it to the fluid of the second, higher energy circuit are performed by a single carbon transfer device, generally indicated at 30 * Device 30 is preferably constructed according to the teachings of Swedish Patents 174,094 and 324,949. is hereby incorporated by reference into the present specification.

At the borehole located in the second flow circuit after the transfer station, the liquid and associated carbon pieces are limited to a free surface of the liquid at a distance from the carburetor inlet 12 communicating with the gas inlet pressure in the gasifier vessel 10 while allowing the liquid and predetermined size to continue. from the discharge station to the flow direction. The pieces of carbon in the restricted state, i.e. in the liquid collection, are transported substantially continuously upwards through the free surface of the liquid to the inlet of the gas container 10. The formation of the liquid collection and the conveyance of the carbon are performed by a mechanical separator device, indicated generally at 32 in Figure 1. The device 32 is preferably constructed in accordance with the teachings of U.S. Patent 3,429,773. ITS Patent 3,843,468 discloses another device that may also be used, and the disclosures of this patent as well as U.S. Patent 3,429,773 are incorporated herein by reference.

It is also an object of the present invention to substantially continuously purify the fluid flowing in the first and second circuits with accompanying pieces of carbon of less than a predetermined size by substantially continuously separating these fine pieces of carbon therefrom. In the device schematically illustrated in Figure 1, the separation is performed in both circuits, although it will be appreciated that it can only be performed in the other circuit. In the diagram shown in Figure 1, separation is performed in both circuits by centrifugal separators 34 and 36 connected to the first and second circuits, respectively, to fine carbon separation stations between the transfer station and the pumping station in the first circuit and between the discharge station and the pumping station in the second circuit.

The carbon dosing and feeding device 24 can be of any construction. The apparatus schematically shown in Figure 1 includes a conveyor 40 for conveying carbon pieces of a specified size from a repository, not shown, to the open upper end of a funnel-shaped receiving container 42, the lower end of which communicates with the open upper end of the housing 44. The housing 44 is substantially cylindrical with its axis horizontal and 7, -. r -.

b b 6 J s it has a vane rotor or star wheel 46 arranged to rotate about an axis concentric with the axis of the housing 44. The star wheel 46 is mechanically driven at a constant speed to ensure a continuous steady supply of carbon pieces to the fluid of the first flow circuit. If desired, the hopper 42 can be vibrated, e.g. with a vibrator 48, to ensure a continuous flow of carbon pieces from the hopper 42 to the star wheel housing 44.

The open lower end of the star wheel housing 44 communicates with the open upper inlet end of the carbon supply chamber 50 forming the carbon supply station of the first flow circuit 20. The open lower end of the carbon supply chamber 50 communicates directly with the upper inlet end 52 of the sheath 54 of the transfer device 30. The carbon supply chamber 50 receives fluid pumped by the pump 22 of the first flow circuit 20 from a conduit 56 terminating near the open upper end of the chamber, as best seen in Figure 2. flow together from the open lower end 58 of the transfer device 30 to the first flow circuit 20, pass through line 60 to the centrifugal separator 34. The purified liquid leaving the separator 34 completes the circulating flow in the first circuit 20 as it is led by pipeline 62 to the suction side of the pump 22.

The housing 54 of the transfer device 30 also has an inlet 64 from which a high energy liquid flowing in the second flow circuit 26, e.g. through line 66 from pump 28, enters, and an outlet 68 communicating with line 70 to mechanical separator 32. * The transfer device 30 is shown vertically in Figure 2. in connection with the first flow circuit 20 and horizontally to the second flow circuit 26. The transfer device 30 comprises, as best seen in Figures 3 and 4, a pocket drum 72 with two rows of diametrically through pockets 74 »each row having two passages perpendicular to each other so as to form four openings. to the circumference of the drum in each row. The two rows of pockets are parallel with the second row displaced circumferentially at an angular distance of 45 ° from the second row, as shown in Fig. 4. The pocket drum 72 is surrounded by an outer sheath, i.e. a housing 54, and arranged to rotate inside the inner sheath 76. It can be clearly seen from Figure 3 that the inner jacket 76 has four openings 70, 80, 82 and 84 »at equal intervals, which are aligned with the inlet opening 52, the inlet opening 64» and the outlet opening 68, respectively. Each opening of the inner jacket 76 is more than twice the sum of the two pockets 74 of the pocket drum and the intermediate portion 86 is positioned midway through each opening of the inner jacket to divide it into two parallel openings, as clearly seen in Figures 3 and 4.

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The pocket drum 72 may be either cylindrical or conical; this is shown in Figures 3 and 4 as the diameter of the conical drum increases in the direction of the handwheel 88 used to adjust the clearance (Figure 3) · The conicity of the drum 72 allows the clearance of the drum 72 and the inner jacket 76 to be adjusted; in addition, the increase in play due to wear can be compensated for by rotating the handwheel 88 which pushes the drum 72 toward the shaft drive end 90 shown in Fig. 3. The rows of pockets 74 passing through the drum 72 pass each other to form channels passing through the drum which terminate in the same diametrical line on the circumference of the drum. As the pockets run side by side, the pockets become thinner and at the same time widen, which is seen in Figure 2. The thinning is necessary to allow the channels to be bypassed, and the widening maintains an almost constant cross-section of the pocket for fluid and carbon flow.

Through the inlet 52 of the transfer device 30, the pieces of carbon accompanying the liquid are conveyed by gravity and movement to the liquid by the pump 22 through the openings 78 and 82. A strainer or strainer 92 is placed in each of the openings 82. Each strainer has holes or slits sized to allow water to pass through and fine pieces of carbon of a size (nominal diameter e.g. about 3 * 2 mm) which adversely affect the gasification process, as stated above. , but retain larger pieces, including pieces of carbon of a predetermined size range, which thus remain in the drum in question. pocket 74. As the filled pocket rotates and begins to approach a position perpendicular to the pocket filling position, fluid from the second flow circuit 26 from the pump 28 flows by force from line 66 through orifice 80 into the pocket, causing carbon pellets to escape from pocket 84 through orifice 70. in the filling position, all the pieces of carbon have been removed from it to line 70, leaving only liquid in the pocket.

The liquid remaining in the pocket, which is fluid flowing in the second flow circuit, is (1) removed from the second flow circuit before the pocket re-rotates to the filling position and (2) connected to the fluid flowing in the first flow circuit when the pocket rotates again to the filling position. Thus, each successive amount of liquid removed from the first flow circuit and connected to the second flow circuit and the amount of carbon therein have a corresponding amount of liquid removed from the second flow circuit and connected to the first flow circuit. Thus, an inherently continuous equal volume transfer or exchange is performed between the two flow circuits, which of the same volume exchange also naturally results in a net flow of carbon pieces from the first flow circuit to the second and an equal net flow of liquid from the second flow circuit to the first flow circuit.

The pocket drum 72 rotates continuously, but the pockets of one row of pockets are filled and emptied periodically. Since a parallel row of pockets at an angular distance of 45 ° from the above in the circumferential direction is also filled and emptied intermittently, the sum of these two intermittently filled and emptied pocket rows is "continuous". The continuous operation is thus caused by the mutual circumferential displacement of the two parallel pocket rows, shown in Fig. 4, because when one pocket leaves the outer casing or housing inlet, the other pocket arrives at the same inlet, thus maintaining a constant open cross section and first flow cross section. through the discharge openings 80 and 84 of the second flow circuit, which makes the filling and emptying circulation systems continuous.

The transfer device 30 is characterized by many important features. The first of these is its ability to transfer pieces of carbon from a first flow circuit to another, higher energy level flow circuit without forced sealing or sealing surfaces. According to the present invention, the rotating pocket drum 72 does not need to be in close contact with the inner sheath 76, but may be spaced therefrom. Since the openings 78 and 82 have a lower pressure than the openings 80 and 84, fluid flow leaks from the openings 80 and 84 to the openings 78 and 82 through said clearance. The fluid flow through the clearance is kept small by keeping the clearance narrow. A small stream of liquid performs lubrication and cleaning, thus preventing the rotating drum 72 from sticking to the sieve jacket 76. Another unique feature, or feature, of the transfer device 30 is the removal of fine material through the screen. When filling the pockets 74 of the rotating drum 72, the fine pieces of carbon are drawn through the circumferential slits of the screen 92. The slits are dimensioned to remove pieces smaller than a specified size range, as stated above. The construction of the transfer device 30 is such that self-cleaning of the screen 92 is achieved, whereby the cleaning is performed by the edge of the pocket of the rotating drum as it passes over the slits. Third, one or more grooves 94 may be made in the inner sheath 76 at the edges of the openings 80 and 84, as illustrated in Figure 4. The grooves 94 are given a circumferential dimension larger than the radial dimension, so that the fluid flowing from the pump 28 under high pressure into the pocket openings 80 and 84 is subjected to a strong throttling effect. As a result, the shocks and vibrations at the junction of the pocket and the opening are milder, which reduces the tendency of the carbon pieces to break. And finally, the liquid used as a transport medium tends to prevent the cutting of carbon pieces in two ways when the edge of the pocket of the rotating drum closes the housing filling opening 78 10 56695 in connection with the drum pocket when the drum rotates at low speed, preferably 5-10 rpm. The liquid gives some buoyancy to the carbon pieces, as their density is preferably only 1.2 to 1.4 times the density of the liquid. Because the density of the carbon pieces is only slightly higher than the density of the liquid, the edge of the pocket tends to push the carbon pieces away rather than squeezing or cutting them between itself and the edge of the housing filling opening. As the filling pocket moves away from the filling opening and at the same time closes, the pocket of the adjacent pocket row approaches the filling opening fully open, so that most of the liquid flow passes through this pocket, carrying all the carbon pieces without leaving any or almost all of the closing pockets sulfur-free.

The liquid driven by the centrifugal pump 28 conveys successive amounts of carbon particles and liquid from the device 50 via line 70 to a mechanical separator 52. This separator, which may be of any known type, is shown as an inclined screw conveyor 96 with a lower end surrounded by a screen 98. Screw and strainer is placed inside the housing 100. The mechanical separator 52 may also be vertical instead of the slope shown. The slope of the mechanical separator from 50 to 60 ° has been found to be optimal. The pieces of carbon and liquid carried along line 70 enter the lower end of the housing 100 and begin to move toward the inlet 12 of the carburetor 10. The liquid that carried the pieces of carbon into the housing 100 is allowed to continue to move in the second flow circuit through the screen 98 and line 102. The screen 98 is dimensioned to allow finely divided carbon to pass through the liquid (nominal diameter e.g. about 5 mm and smaller). Note that the fluid level in the housing is kept at a constant height of 100. The function of the screw conveyor 96 is to continuously transport the pieces of carbon in the housing diagonally upwards through the surface of the liquid and then by gravity through the carburetor inlet 12 to the carburetor 10 itself as the carbon pieces pass through the free surface of the liquid. a barrier that prevents gas from leaking from the carburetor 10 through the mechanical separator 52. The liquid and all fine pieces of carbon are conveyed down line 102 to a centrifugal separator 56 where finely divided carbon is removed from the liquid by centrifugal force to obtain purified liquid flowing through line 104 to centrifugal pump 28. From there, liquid is conveyed through line 66 to transfer device 50 inlet or port 64. cycle.

The fluid levels in the feed chamber 50 and the mechanical separator 52 are maintained by respective fluid level control valves 106 and 108. The fluid level in the supply chamber 50 represents a free surface under low (e.g., atmospheric) pressure, and the free surface forming fluid is part of the first flow circuit 20 fluid. The liquid tao of the separator 52 represents a free surface which is under a high pressure (e.g., 21 kp / cm) at the inlet of the gas nozzle, the liquid forming the free surface being part of the liquid in the second flow circuit 26. Looking at the movement of fluid into and out of both flow circuits without the effect of the fluid level control valves 106 and 108, it is apparent that the rivet level of the supply chamber 50 tends to rise as the fluid level of the separator 32 tends to decrease. Liquid enters the first flow circuit 20 and leaves the second flow circuit 26 due to the net flow of liquid from the above-mentioned natural volume transfer of the transfer device 30 and from the high pressure zone to the low pressure zone due to the above-mentioned liquid leakage in the transfer device 30. In addition to the above-mentioned net flow of fluid between the circuits, fluid is lost from each circuit as it adheres to the fine pieces of carbon removed from the separation 34 and 36, and from yet another circuit as it adheres to the pieces of carbon fed to the carburetor. The fluid level control valve 106 opens when the level sensor detects a fluid level rise in the chamber 50, allowing fluid in the first flow circuit to flow from the chamber through the respective ring 112 and 114 connected in series with the line 112 and 114 to the level control tank 116. The centrifugal pump 118 draws fluid from line 120 line 122 to liquid level control valve 108. Liquid level control valve 108 opens as its sensor senses liquid level drop in housing 100 supplying liquid through line 124 to second flow circuit 26. Since liquid is lost in centrifugal separators 34 and 36 and lost to some extent 116.

A significant overall advantage in the process is achieved when the spent liquid is oil and light tar fractions, as they are subjected to the process in a carburetor and recovered therefrom for use at least in part as an addition liquid.

The recovery is schematically illustrated in Figure 1, in which hot gases (containing oil and tar vapors) flow through the carburetor outlet 18, are then subjected to conventional scrubbing treatment, designated 126, to purify the gases and obtain an oil and light tar fraction 128. This oil and light tar fraction 128 is then fed to the tank 116 through a liquid level measuring valve 130. The arrangement presented is advantageous not only for the efficient use of the substance but also for the efficient use of heat.

Referring specifically to Figure 5 *, a flow chart of a modification of the present method and apparatus is shown herein. In the system of Figure 5, pieces of coal belonging to the above-mentioned size range are fed from the storage silo 150 directly to the open upper end of the shaft 152 by a suitable feed device 154, which is a vibrating conveyor. Other known feeding devices, such as a reciprocating plate conveyor, can be used. The vibratory conveyor is preferred over the star wheel device 46 described above because the latter is characterized by the formation of carbon powder as the wheel rubs against the pieces of carbon.

It is preferred to use a simple cylindrical shaft 152 than a chamber 50 having the cylindrical screen 110 described above.

The screen 110 was used because of the liquid level control tank 116 and the centrifugal separator 34. Since the level control tank 116 and the separator 34 have been eliminated from the system of Fig. 5, as will be seen later, the cost of the screen 110 and any operating problems due to its clogging are now eliminated.

The shaft 132 forms part of a first, low-pressure flow circuit in which a certain volume of liquid, in this case preferably water, is kept free. As before, the shaft 152 extends to the transfer device 156, which is similar in structure to the device 30 described above. From the transfer device 156, the first flow circuit is formed by a first line 158 to the circulation pump 160 and a second line 162 to the shaft 152 from the pump 160.

As before, the transfer device 152 is also placed in a second high-pressure circuit, which consists in part of a line 164 which goes from the transfer device to a separator 166 having a structure similar to the device 32 described above and connected to a carburetor 168. connecting the separation device 166 to the circulation pump 172, and a line 174 connecting the pump 172 to the transfer device 156.

Approximately all-sized carbon is fed directly to the atmospheric pressure shaft 152 from the silo 150 by the vibratory conveyor 154 as the coal falls under its own weight into the water in the shaft through this free surface. The carbon feed rate is determined by the rate at which the carbon is consumed in the carburetor 168, Pump 172 causes high energy fluid to flow in the second circuit from transfer device 156 to separator 166, Separator 166 lifts carbon from high energy liquid through this free surface. Pump 160 circulates the low energy fluid in the first circuit. The carbon is introduced into this circuit through the free surface of the liquid in the shaft 152, as stated above. The transfer device 156 transfers carbon from the low energy circuit to the high energy circuit.

As the carbon entering the pockets of the transfer device 156 displaces the liquid from the high energy circuit, the low energy circuit receives liquid and the high energy circuit loses. In addition, leakage at device 156 increases this yield and waste. Such a transfer of liquid to the low energy circuit results in a rise in liquid level in shaft 152. This rise in liquid level is prevented by opening the level control valve 176 in line 178 diverging from line 1358695, which transfers excess fluid to a separate fine carbon powder separator via line 180. A pump can be connected to line 180 if the separation device is too far or upward, which prevents self-weighted flow. The independent carbon powder removal system can be of any construction and be located, for example, next to the feed coal cleaning device or at the place where the carbon powder is used. As an illustrative example, a carbon powder removal system is shown herein as a precipitator 182 which supplies water to a high pressure circuit to replace water lost therefrom. It is clear that the addition water to the high pressure circuit can be supplied from some other suitable source.

The amount of addition water is taken care of by the level control valve 184, which keeps the free surface of the liquid in the separator 166 at a constant height. The feed liquid is supplied to line 170 by line 186 including valve 184 and is pressurized with high energy fluid by pump 188, suction line 190 exiting precipitator 182. Since fluid always moves out of the high energy circuit and subsequent fluid exit from the low energy circuit must be replaced by a new high energy circuit. All of the carbon powder is removed as the liquid passes through the screen of the transfer device 156. Some of this carbon powder is removed while filling the pockets of the device 156. The remaining powder is drawn through the screen of the separator 166 and returned to the device 156. Just before filling with carbon The 156 pockets contain a liquid that was in the flow circuit of the high energy liquid a moment earlier, this liquid would contain carbon powder passed through the screen of the separator 166. The liquid is carried with the carbon powder through the screen of the transfer device during the filling of the pockets. a. The net removal of the liquid containing the carbon powder and the subsequent replenishment with pure liquid keeps the carbon powder content of the liquid in the system low and prevents the powder from entering the carburetor.

It is clear that although the present invention has been disclosed as a complete gasification process in which the solids leaving the gasification vessel are ash, the present invention also includes processes in which the produced gas can be considered a by-product, such as all known decarbonation processes including coking processes.

Thus, it is obvious that the objects set by the present invention have been fully achieved. It should be noted, however, that the above preferred particular embodiment has been shown and described to illustrate the functional and structural principles of the invention and that it may be modified without departing from these principles. Therefore, the invention encompasses all modifications which fall within the scope and scope of the following claims.

Claims (11)

A method of producing a gas from a gas generating agent, such as coal, having a predetermined particle size range having a lower limit of about 6 mm in nominal diameter by continuously feeding these particles under a predetermined elevated inlet pressure to a carburetor inlet member, the carburetor being continuously heated , which would be adversely affected by the presence of considerable amounts of particles smaller than the above-mentioned predetermined size range, characterized in that the continuous feeding comprises the steps of: - enclosing a liquid in a first circuit with a first liquid collection forming a first free surface on the carburetor tank inlet low pressure conditions compared to the elevated pressure, - introducing particles of said size range into the fluid of said first closed circuit through this free surface, - enclosing the fluid in a second circuit which is circulating and has a second liquid collection forming a second free surface in communication with the elevated pressure of the inlet member of the carburettor device, - continuous circulation of liquid in said second circulating circuit by pumping it at a pump station spaced from the second liquid collection, from the circuit and introducing these successive batches of liquid and accompanying particles into the fluid flowing in said second circuit at a location between the pump station and said second fluid collection, - assembling particles of said size range into said second fluid collection, and - conveying the assembled particles upwards through said second free fluid surface and a carburetor inlet member. A method according to claim 1, characterized in that for each successive small batch of liquid removed from said first circuit and connected to said second circuit and associated particles, a corresponding small batch of liquid is removed from said second circuit at a location between the pumping station and said second fluid collection, and is combined with a liquid of said first circuit so that an equal volume exchange occurs between the circuits, resulting in a net flow of particles in said size range from the first circuit to the second circuit and an equal net flow of liquid from the second circuit to the first circuit. 5 66 ~ 5 15 A method according to claim 2, characterized in that said second free liquid surface is maintained at a substantially constant height level by pumping sufficient liquid from the liquid reservoir to said second circuit to compensate for the aforementioned net loss from the second circuit to the first circuit and other liquid losses of the second circuit. A method according to claim 3, characterized in that said first free surface is kept at a substantially constant level by taking sufficient liquid from the first circuit to maintain this level. A method according to claim U, characterized in that the liquid taken from the first circuit to maintain the height level of the first free liquid surface is treated to obtain an amount of liquid free of fine particles and this amount of liquid is used as a liquid reservoir to compensate for liquid losses in the second circuit. A method according to claim 5, characterized in that the treatment giving said amount of liquid comprises collecting a liquid taken from the first circuit to maintain a free surface level in a precipitator, where the fine particles are concentrated in a part of the liquid to be conveyed, while the remaining liquid is free of fine particles. A method according to claim U, characterized in that said successive small batches are removed from the first circuit by maintaining a continuous flow of liquid and particles therefrom from said first fluid collection to the batch transfer point in the first circuit, preventing flow of particles in a predetermined size range at the transfer point. particles smaller than a predetermined size range flow past the batch transfer point, and sequentially removing the blocked particles and the amount of fluid carrying them at the time of removal corresponding to said batches. A method according to claim 7, characterized in that the continuous flow of liquid and particles therein from said first liquid collection is maintained by pumping a part of the liquid flowing outside the batch transfer point back to said first liquid collection. A method according to claim 8, characterized in that the liquid pumped from the liquid reservoir to the second circuit is kept substantially free of fine particles smaller than a predetermined size range by separating the fine particles from the part of the liquid used. A method according to claim 9, characterized in that the part of the spent liquid from which the fine particles have been separated flows in the first circuit between the batch transfer point and said first liquid collection. 56695 16 A method according to claim 2, characterized in that successive small batches are removed from the first circuit by maintaining a continuous flow of liquid and particles therefrom from said first fluid collection to the first circuit batch transfer point, preventing flow of particles in a predetermined size range from the batch transfer point. the particles are allowed to flow outside the batch transfer site, and sequentially removing the blocked particles and the amount of liquid transporting them at the time of removal equal to said batches. A method according to claim 11, characterized in that the continuous flow of liquid and particles therein from said first liquid collection is maintained by pumping a part of the liquid flowing past said batch transfer point back into said first liquid collection. £ 6696 17