US2150528A - Gasification of liquid fuels - Google Patents

Description

March 14, 1939.

E. J. THER ET AL 2,150,528

- GASIFICATION OF LIQUID .FUELS 5 Sheets-Sheet 1 Filed April 25, 1936 Ira/Galbra- Ewe/2&1 .7728)? j orra'fili Mason, 9777 141 40 *M/W March 14, 1939. E. J. THER ET AL GASIFICATION OF LIQUID FUELS Filed April 25, 1936 5 Sheets-Sheet 2 I 72216222 576. 617/6 JT/ZQ, A70 rrfili/Vaaom March 14, 1939.

E. J. THER ET AL 8 GASIFICATICN OF LIQUID FUELS Filed April 25, 1936 3 Sheets-Sheet 3 Patented Mar. 14, 1939 UNITED STATES GASIFIGATION OF LIQUID FUELS Eugene J. Ther, Oak Park, and Morris B. Mason,

Chicago, Ill.

Application April 25,

9 Claims.

Our invention relates to the gasification of relatively volatile liquid fuels and it is concerned more particularly with a method of and means for forming a substantially stable gas from a relatively volatile liquid fuel.

The principal object of the invention is to provide improved method of and means for forming a substantially stable gas from a relatively volatile liquid fuel.

Another Object is the provision of equipment for this purpose which is compact, easily handled, easily installed and simply operated.

Another object is the provision of an improved method for gasifying a relatively volatile liquid fuel so that the gas so produced will be stable and will follow the gas laws.

Another object is the provision of improved control means and structural features in mechanism of the character indicated.

An important object of our invention is to effect the cooling of the air pump in a novel and effective manner.

Other objects and features of the invention will be apparent from a consideration of the followa ing detailed description taken with the accompanying drawings, wherein Fig. l is a plan view of a preferred embodiment of the invention;

Fig. 2 is a side elevational View looking at 1 from the left side thereof.

Fig. 3 is a sectional view taken along the line 3-4 of Fig. 1 looking in the direction of the arrows, showing the gasifying cylinders.

Fig. t is a sectional view along the line 4-4 of r- Fig. 1 looking in the direction of the arrows and showing a liquid fuel filtering means.

Fig. 5 is a slightly enlarged sectional view partly in elevation taken along the-line 5-5 of Figure ,1 looking in the direction of the arrows, showing the manner of feeding the lubricating oil to the compression pump.

Fig. 6 is a sectional view taken along the line 6 -6 ,of Fig. 1, showing the compressor or air pump and the means for effecting the cooling of the same.

According to the mean features of our invention, we deliver from suitable pumps measured and definite quantities of air and a relatively vol.- atile liquid fuel, preferably a hydrocarbon such as hexane, to a gasifying mechanism. This mechanism, shown principally in Fig. 3, receives the liquid hydrocarbon and air separately but in such a manner as to form a substantially atomized mixture im ediatel when t a and liquid hy- 5 droca-rbon meet. Thisxatomized mixtureis then 1936, Serial No. 76,326

(or. zen-9 forced through a plurality of relatively fine mesh screens, the continuity of the screens being broken up by a plurality of relatively smaller passageways through which the partially gasified hydrocarbon and air pass, the effect being to cause a 5 compression and expansion of the gasified fuel at a pluralityof times during the passage through the screens. The screens are all of relatively fine mesh but may increase in fineness toward the dc.- livery end of the mechanism. Although the fuel 10 mixture, as it passes through the screens, decreases in temperature due to gasification and expansion, and emerges from the final cylinder at a low temperature, in the neighborhood of 32 F. or slightly above, a true gasification is 15 made to take place. To this end, we employ a metallic material in the screens preferably having a content of nickel or copper. Nickel is highly satisfactory but a combination of the two, about the proportions existing in Monel metal, produces 2n, the best results. An alloy containing approximately 30% nickel and 7.0% of bronze has been found to be very satisfactory. We have found that the gasifying action is substantially com: plete when a comparatively large number of screens is employed, even though the temperature at which the gasification takes place is relatively low. We have also found that the restricted passageways intermediate screen sections have some effect in promoting gasiflcation.

The gas produced in this manner behaves as a true gas. Except for minor changes in pressure (which is expected from a consideration of the gas laws), change of temperature seems to have no effect upon the gas when confined under pres.- sure in a container. A tank of the gas may be produced and allowed to stand in the open at near zero temperatures for twelve to twentyfour hours and instead .of suffering in loss of B. t. u, content, it actually seems to improve with 40 the passing of time. We are unable to explain the reason for this apparent improvement, but many tests appear to demonstrate the fact. The life of the gas appears to be indefinite, as it be.- haves at least as well after. three or four days standing as when originally made.

The gas so produced can be burned in all usual gas burning equipment. It can be piped to the place of use and can beused in the same Way that ordinary natural gas or commercial water gas of commerce is used, care being taken, of course, to adjust the burners to the B. t. u. content of the particular gas produced.

We can gasify, in the manner described, many different types of hydrocarbons or mixtures of hydrocarbons such as are found in commercial fuels. Hydrocarbon liquid fuels having an initial point of about F. and an end point of approximately 250 F. to 280 F. are well suited for our purposes. Our best results, however, are secured in the handling of hydrocarbons running between the so-called gas oils and the higher grades of gasolines of commerce. If a fuel having too high an end point is employed, residues will be left which may necessitate cleaning the equipment at intervals. In general, it is desirable to employ a liquid fuel which leaves a minimum of residue. Our process will operate not only on hydrocarbon liquid fuels but will also produce gas of a very suitable nature from other liquidfuels such as ordinary ethyl alcohol. Admirable results have been obtained with ordinary hexane. Whenever we refer in the specification and claims to hydrocarbons, it will be understood that we mean also to include fuels of a, similarly volatile nature such as alcohol, benzol, etc.

We have found that where the ordinary air pump with its exterior vanes for air cooling is employed to compress the air which is forced into the atomizing or mixing chamber or cylinder, the pump increases considerably in temperature, in fact, so much so that it is not possible to operate the mechanism continuously unless a pump of unduly large size is employed. The overheating of the pump results not only in intermittent operation but, in addition, the quality of the prepared gaseous mixture is not as uniform as it might be because of the variable temperature of the air which is mixed with the volatile liquid fuel. We have overcome this obstacle by providing a jacketed air pump and passing the expanded gaseous mixture from one of the gasifying cylinders into and through said jacket. The cold gaseous mixture abstracts a considerable amount of heat from the air pump and enables the same to be operated continuously at moderate temperatures so that the air exhausted therefrom is at a temperature of the order of '72 to 76 C. and maintains this: temperature over long periods of operation.

Referring now first to Fig. 1, the equipment there shown comprises a base II! which serves to support the mechanism now to be described. A fuel pump II is driven from one end of the motor shaft l2 connectedto a motor (not shown), and an air pump I3 is driven by a continuation of the shaft. Air is drawn by the pump l3 through a filtering chamber l4 provided at its bottom surface with a plurality of air intake ports [5. Disposed within said filtering chamber 14 is a screen I! of metal gauze or the like having very fine openings and which serves as the air filter. As is clearly shown in Fig. 5, the chamber I4 is formed in two sections which are connected together through the medium of screw threads. The upper section is formed with an interior abutment I8 whereby a chamber I9 is formed into which the air inlet pipe 20 connects and which leads to the air pump or compressor l3. An opening 2| in the abutment 18 serves to connect the interiors of the chambers 14 and I9.

We have devised a simple and effective means for lubricating the moving parts of the air pump or compressor 13 which, in our prefered embodiment, is of the well known rotary type, as best shown in Fig. 6. This comprises a rotor 2i keyed to the motor shaft I2, the rotor having the usual vanes 22, and the whole' pump is arranged to withdraw previously filtered air from an intake passageway 23 and force the same out under pressure at an exhaust passageway 2A. In order to lubricate the pump 13, We introduce the lubricating oil into the air stream which. is drawn through said pump. To this end, we provide an oil reservoir 25 which is provided with the conventional float 26 mounted upon the vertically disposed rod 27 which is slideable in a bearing 28, integral with the upper portion of the reservoir 25, the height of the rod 21 above the top of the reservoir 25 serving to visibly indicate the state of the supply of lubricating oil in said reservoir. The reservoir 25 is provided with an opening in the upper part thereof through which a pipe 30 passes nearly to the bottom thereof. The other end of the pipe 36 extends out of the reservoir 25 and is connected to a lubricating control valve 29 which is provided with a hand operated valve Wheel 3| which can be set to any desired opening. The opposite end of the valve 29 is connected into the chamber I!) by means of a pipe 32. A sight glass 33 is provided in the valve casing to permit the operator to visually regulate the rate of feed of the oil. The mode of operation of the air pump lubricating mechanism will now be apparent. The air which is drawn through the ports was it rushes through pipe 20 creates a suction in the pipe 30 and lubricating oil is drawn therethrough and through the valve 29 into the chamber 19 where it mingles with the air and the mixture is drawn into the air compressor through the pipe 20. By adjusting the valve 29 at the handle or wheel 3|, we regulate the amount of suction on the pipe 30, thereby controlling the amount of lubricant, such as ordinary lubricating oil, delivered through the pipe 32. The excess of lubricant which passes through the air pump is atomized and delivered to the gasifying portion of the apparatus, which will shortly be described, Where it is admixed with the liquid fuel which is fed to such apparatus to be converted into a gas.

The air is delivered from the pump l3 through a delivery line 34 and thence through a pipe 35, provided with a check valve 35 into the gasifying unit. The upper part of the delivery line 3G is provided with a safety or relief valve 36 which is set to open at any desired pressure. A suitable pressure gauge, not shown,-may be connected into the air delivery line to indicate the pressure of air being delivered by the air pump. Further features of the air pump will be referred to hereinafter.

Referring particularly to Figure 2, the fuel pump H comprises a housing within whichare supported apair of spur gears 3'1 and 38, the gear 31 being keyed to motor shaft I2.- Liquid fuel carried in a tank 39 is drawn into the gear pump from a pipe 4|. As shown in Figure 2, the tank 39 is disclosed to be mounted immediately below the apparatus for generating the gas. For household and commercial use, however, it is evident that the tank 39 may be disposed at considerable distance away from the gas generating mechanism proper. For example, the tank 3Q may be placed underneath the earth and may be connected by suitable piping to the gas generating mechanism which may be placed in the household or commercial establishment, as the case may be. A hand operated valve (not shown) is provided for shutting off the supply of liquid fuel, if desired.

Before passage into the pump II, the liquid fuel passes from the pipe 4| through a filter 42,

shown in detail in Figure 4. This filter, which also serves as a selfprimer,comprises a casing formed in two sections, to the upper one of which is connected ametal gauze filter 43, preferably conical in shape. If desired, a plurality of filter screens may be mounted in the filter casing to provide adequate filtering surface for the liquid fuel. The bottom of the filter casing is provided with a pipe 45 which leads into the fuel pump. A pipe 56 is connected to the outlet passage from the fuel pump and connects with a filter chamber 41 whereby the liquid fuel is again. filtered. As shown in Figure 2, the filter chamber 4'! is provided on its interior with two oppositely disposed conical metal gauze filters 48. Connected to the discharge side of said filter chamber is a pipe 49 which connects with a T 5i within which a check valve is disposed. To the T 5! through the medium of a small section of pipe 52 is another T 53 to one opening of which a pressure gauge at is connected. A loy-pass valve 55 is connected to the other opening in the T 53 and this in turn leads to the short section of pipe 56 which is connected into the upper portion of the filter chamber 42. A pipe 51 leads to the gasifying chamber. It will be seen that in the event the pressure within the pipe line i9 exceeds a certain predetermined value, depending upon the setting of the by-pass valve 55, said valve 55 will open and permit the liquid fuel to circulate through the filter casing 42, the fuel pump ii, and the filter chamber il, and this recirculation will continue to take place until pressure condi tions are established whereby the valve 55 will remain closed and the liquid fuel will pass through the line 51 into the gasifying chamber. It will be seen, therefore, that a substantially constant liquid fuel pressure will be maintained in the line 5?.

The gasifying unit includes a plurality of cylinders 53, 59, 6! and 62, each having a plurality of fine meshed screens and connected together to provide restricted passageways as previously set out. The air and fuel both enter the top of the cylinder 58. At this point, we provide an injector and atomizing unit comprising an injector body 63, injector head 69, and a liquid injector nozzle 65. The liquid fuel passes through the pipe 51 into a passageway 66 formed in the injector 53. This passageway extends to form a pipe-like projection which turns upwardly at right angles. The injector nozzle is threaded into the top of this pipe-like projection. The nozzle 65 is provided with a relatively small port 6'1. Immediately above the port we provide a plug 69 in the injector head 64. This plug is removable to clean out the port 61, if required. The entire head 64 may be removed to adjust or change the nozzle 65.

In Fig. 3 at 69 we indicate in dotted lines the position into which the air pipe 35 is connected, it being understood that the delivery end of this pipe does not appear in a section taken as Fig.

3 is. The fuel being delivered in a fine atomizin'g stream up against the head 64' is further broken up and comes down in the form of a spray where it mingles with the incoming air from the pipe 35 and further increases the atomization. Thence the atomized liquid fuel and air mixture passes through the successive sets of screens'and is delivered through a pipe Iii back to the tank 39, where it is maintained above the level of liquid therein. A check valve 12 (Fig. 2)

prevents back pressure from the tank when the motor is not operated Now referring further to the cylinders 58, 59, 6! and 62', these are formed in pairs, 58 and 59 being connected at their lower ends by a restricted passageway 13, and a similar restricted passageway 14 being provided between the cylinders 6| and 62. Each of cylinders 59, BI and 62 is provided with a head 15.

We have found that we obtain excellent results by utilizing an arrangement of screens such as shown in Fig. 3. In the cylinder 58 we show a plurality of cone-shaped screens 16 arranged with the mouths of each pair adjacent each other whereby diamond-shaped sections are formed. While we have shown this arrangement of screens, it is evident that such may be modified, for example, by using flat screens or a combination of flat screens and conical or other shaped screens, the object being to obtain a sufficiently large surface so that there will be a substantial scrubbing action on the fuel-air mixture so that the same will be converted to a uniform, stable gas.

We may, in some cases, employ screens of progressive fineness along the path of movement of the gas, using about an 89 mesh screen in the first stages in the cylinder 58 and a 200 mesh screen at the top part of cylinder 62. Sometimes 7 an advantage is obtained also by increasing the fineness in each cylinder separately. For exam ple, the screens in cylinder 58 may increase from mesh to 150, the screens in cylinder 59 may increase from mesh to 180, etc., thus having a decrease in the fineness of the screens between the cylinders but a gradual increase to the final screens in cylinder 62.

We have previously referred to the novel means which we employ to effect the cooling of the air pump it and we shall now describe these means in greater detail. When the spray of liquid fuel, which is at room temperature in ordinary operation, is converted into the gaseous state in the cylinder 58 as well as in the other cylinders 59, 6| and 62, and when the air from the pump is released into the cylinder 58, a marked cooling takes place due to the resulting expansion. As the fuel-air mixture expands and passes down through the cylinder 58 and upwardly through the cylinder 59, the fuel-air mixture becomes very cold. We lead this cold mixture through a casing or jacket H which surrounds the air pump 13. The cold gaseous mixture is taken from the top of cylinder 59 through the outlet pipe 78 and thence through the connecting pipe 19 which leads into the cooling jacket ll. The cooling casing or jacket ll is provided with a wall portion 8i which insures that the cold gaseous mixture passes substantially entirely around the external peripheral surface of the pump 13 before it emerges from the casing through the outlet pipe 82 which is threaded into the casing 'l'l. The cold gaseous mixture abstracts a considerable amount of heat from the air pump, the temperature of the latter dropping as much as 40 C. and even more, depending upon the conditions of'ope'ra'tion. At the'same time, the temperature of the gaseous mixture rises and when it is then passed through the cylinders 5i and 62 (which contain screens similar to those in the cylinders 58 and 59) there results a more stable,

uniform and drier gas than would otherwise be From the outlet pipe 82, the gaseous mixture passes through the vertically extending connecting pipe 83 into the upper part of the cylinder BI. It then passes downwardly in the cylinder 6!, thence through the passageway 74 into the lower part of the cylinder 62, upwardly through said cylinder 62 and when it emerges at the outlet pipe II, it is stable, dry, uniform gaseous mixture which may be fed directly to suitable burners or it may be passed into a storage tank and kept there under pressure until desired for use. We prefer to pass the finished gaseous mixture into the upper part of the tank 39 where it is maintained above the surface of the liquid fuel until it is desired to be used.

In Figure 2 we disclose a mercury-operated or other suitable switch 84 connecting with the cooling jacket of the air compressor. Thus, when the pressure within the tank 39 drops below a certain predetermined figure, the mechanism will begin to operate.

It should be noted that the cooling jacket communicates with the space above the liquid fuel in tank 39 and within which the prepared gaseous mixture is stored under pressure. When said pressure decreases below a set value, the mercuryoperated switch operates to close a contact through to the motor and the mechanism continues to function until the gaseous pressure built up in the tank 39 rises to a predetermined value at which point the mercury-operated switch will again operate, this time to shut off the motor.

By designing the air pump and fuel pump as to give approximately the proper relative output for each at similar speeds, we are enabled to drive both of the pumps directly from the electric motor. If anything, the fuel pump may have a slightly higher capacity than needed. In other words, it is designed to supply enough liquid fuel to give substantially the highest B. t. u. gas possible. When this amount is cut down, part of this liquid is by-passed. No matter what the setting, the amount of air delivered remains the same.

In the preferred manner of operating our equipment, all of the gas generating apparatus, fuel tanks, etc., are placed out of the building. We then run a pipe line from the top of the tank 39 into the building, employing a pressure regulating valve to cut down the pressure of the gas delivered through the line. This pressure regulator, or pressure reducing valve as it may be termed, is set to any suitable value depending upon conditions. When employing a relatively small unit such as that pictured in the drawings, and mounting such unit immediately adjacent a building in which the gas is to be used, we find that a pressure in the pipe of about two to four and one-half inches of water above atmospheric pressure is very satisfactory. This will be found to conform generally to the pressure usually found in gas lines.

The general manner in which our apparatus operates is clear from the preceding description. For the information of those skilled in the art, however, we shall refer somewhat more in detail to the operation. The tank 39 is first filled to a suitable level with the liquid fuel from which the gas is to be made. The electric current to the motor is delivered by closing a master or line switch (not shown). The switch 84 having previously been regulated to operate between certain pressures, current is now delivered to the motor and the armature thereof turned, thus operating both the liquid pump 1 I and air pump l 3. As soon decrease in temperature.

as the motor is started, liquid fuel and air are delivered to the part of the apparatus shown in Fig. 3, and gas is delivered through the pipe H to the top part of the drum 39.

The character of gas generated is determined by the size of the port 61 and the pressure of liquid in the line, as fixed by the by-pass valve. We have found that if this port is made very small, substantially the same amount of liquid will be delivered therethrough independent of the pressure behind it. We prefer, however, to employ a port of slightly larger size so as to control the amount of liquid delivered by means of the pressure. We have used orifice openings varying in diameter from .002 to .005 inch, such, however, being dependent upon the rate of consumption of the gas which is desired. That which does not pass through the pipe 51 passes by way of the check valve 55 back into the chamber 42 in the form of a liquid and circulates in the manner previously described. The amount of liquid delivered may also be controlled by the valves suitably disposed in the line 49, but this is not the preferred method.

In a preceding part of thisspecification,we refer briefly to the temperature at which the gasification is carried on. The exact temperature is, of course, determined in large part by the temperature of the air in which the unit is placed.-

The rapid expansion which takes place in the gasifying unit, as previously described, causes a Without the use of our novel cooling means, and employing the conventional air cooling vanes on the pump, the air which is discharged into the gasifying cylinder 58 has a temperature in excess of C. when the pump has been in operation but a relatively short time due to the friction created by the compression of the air. Our cooling means results in decreasing the temperature of the air fed to cylinder 58 to approximately '72 to 76 C., or higher or lower depending upon various details, and this temperature is maintained sub-- stantially constant through long periods of operation of the pump. As the gaseous mixture passes through the various cylinders, it becomes cooled and when it emerges from the final cylinder it is quite cold, possessing a temperature approximating 32 F. or slightly above. The resulting gaseous mixture, however, is a substantially stable gas.

By a proper control of the amount of liquid fuel fed to the gasifier, we can regulate the B. t. u. content of the final gas. We have successfully produced a gas having as low a B. t. u. content as 500 as well as a maximum of 1450. The relatively high B. t. u. content gas is sometimes of extreme value in industrial work, particularly when a reducing or carbonizing atmosphere is desired. We also find it unnecessary to preheat either the air or gas going to the burners in order to obtain substantially complete combustion.

It is apparent that various modifications may be made without departing from the spirit of our invention. Thus, the number of cylinders may be increased or decreased as desired or as necessitated by the requirements at hand. Similarly, the size of the cylinders, pumps, etc. may be varied to suit the capacity sought.

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

1. An apparatus for producing a substantially stable gaseous mixture from a relatively Volatile liquid fuel and air comprising a liquid fuel pump, an air pump, means for delivering liquid fuel and air from said pumps to a gasifying chamber, the fuel and air thus delivered forming a gaseous mixture which in its passage through the chamber expands and thereby becomes cooled, and means for utilizing the cooling effect of said mixture to effect a cooling of said air pump.

2. The structure of claim 1 wherein the last mentioned means comprises'a jacket surrounding the air pump at least in part and through which the cooled mixture is passed.

3. An apparatus for producing a substantially stable gaseous mixture from a relatively volatile liquid fuel and air comprising a liquid fuel pump, an air pump, at least one gasifying chamber which is provided with a series of relatively fine mesh screens, means for delivering liquid fuel and air from said pumps to one of said chambers, the fuel and air thus delivered forming a gaseous mixture which in its passage through the chamber expands and thereby becomes cooled, and means for utilizing the cooling effect of said mixture to effect a cooling of said air pump.

4. The structure of claim 3 wherein the last mentioned means comprises a jacket surrounding the air pump at least in part and through which the cooled mixture is passed.

5. An apparatus for producing a substantially stable gaseous mixture from a relatively volatile liquid fuel and air comprising a liquid fuel pump, an air pump, a plurality of gasifying chambers each of which is provided with a series of relatively fine mesh screens, means for delivering liquid fuel and air from said pumps to only one of said chambers, the fuel and air thus delivered forming a gaseous mixture which in its passage through at least said last mentioned chamber expands and thereby becomes cooled, means for utilizing the cooling effect of said mixture to abstract heat from said air pump and thereby raise the temperature of said mixture, and means for passing the heated gaseous mixture through at least one of the other gasifying chambers.

6. An apparatus for producing a substantially stable gaseous mixture from a relatively volatile liquid fuel and air comprising a liquid fuel pump, an air pump, a plurality of gasifying chambers each of which is provided with a series of relatively fine mesh screens, means for delivering liquid fuel and air from said pumps to only one of said chambers, the fuel and air thus delivered forming a gaseous mixture which in its passage through at least said last-mentioned chamber expands and thereby becomes cooled, a jacket surrounding the air pump at least inpart, means for passing the cooled gaseous mixture through said jacket, and means for leading the gaseous mixture therefrom into and through at least one of the other gasifying chambers.

7. An apparatus for producing a substantially stable gaseous mixture from a relatively volatile liquid fuel and air comprising a liquid fuel pump, an air pump, a plurality of gasifying chambers each of which is provided with a series of relatively fine mesh screens spaced from each other in vertical relation, means for delivering liquid fuel and. air from said pumps to the top part of only one of said chambers, the fuel and air thus delivered forming a gaseous mixture which in its passage through said last-mentioned chamber and at least one other of said gasifying chambers expands and thereby becomes cooled, a jacket surrounding the pump, means for passing the cooled gaseous mixture through said jacket to abstract heat from said pump, and means for leading the gaseous mixture from the jacket into and through at least one other gasifying chamber.

8. The apparatus of claim 6 wherein the fine mesh screens are made of a metal.

9. The apparatus of claim 7 wherein the fine mesh screens contain a substantial content of a metal of the class consisting of copper and nickel.

EUGENE J. THER. MORRIS B. MASON.

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