US3375175A - Pyrolysis of coal - Google Patents

Description

March 26, 1968 R. T. EDDINGER ETAL PYROLYS I S OF COAL Filed Jan. El, 1965 TYPICAL FLOW SHEET 2 Sheets-Sheet 1 FIG. I.

HIGH VOLATILE B BITUMINOUS COAL COAL CRUSH ED FOR FLUIDIZATION OVERHEAD TO CONDENSER STAGE l-FLUIDIZED BED DRYING AND PREHEATING HOT FLUE GAS OR OTHER INERT GAS OVERHEAD TO CONDENSER STAGE 2- FLUIDIZED BED FIRST PYROLYSIS soc-900w 24-25% TOTAL OILY LIQUID l0 -3o% TOTAL sAs' OVERHEAD TO FLUIDIZE AND HEAT STAGE 2 STAGE 3-FLUlDlZED BED SECOND PYROLYSIS OVERHEAD TO FLUIDIZE AND 7 HEAT STAGE 3 STAGE 4- FLUIDIZED BED AND HEAT DEVELOPMENT l5OO|8OOF CALCINATION,PARTIAL GASIFICATION AIR OR OXYGEN TOFLUIDIZE CHAR 35 T0 60% INVENTORS RALPH TRACY EDDINGER JOHN F. JONES BY LEONARD SEGLIN m 2." PM

March 26, 1968 R. T. EDDINGER ETAL PYROLYSIS OF COAL Filed Jan. 21!, 1965 TYPICAL FLOW SHEET 2 Sheets-Sheet HIGH VOLATILE A BITUMINOUS COAL COAL CRUSHED FOR FLUID I ZATION OVERHEAD TO CONDENSER ITO IO/ OF DRYWEIGHT I FLUE GAS CHAR PARTS 1 PART OVERHEAD TO CONDENSER STAGE 2-FLUIDIZED BED FIRST PYROLYSIS.

25 32 TOTAL LIQUID IO -30 TOTAL GAS OVERHEAD TO FLUIDIZE STAGE 3- FLUIDIZED BED sEco D PYROLYSIS OVERHEAD TO FLUIDIZE RECYCLE STAGE 4- FLUIDIZED BED THIRD PYROLYSIS 95o- |oso F OVERHEAD T0 HEAT AND FLUIDIZE STAGE 5 FLUIDIZED BED CALCI N ATION, PARTIAL GASI FICATION AND HEAT DEVELOPMENT AIR OR OXYGEN CHAR 30 TO 55 INVENTORS RALPH TRACY EDDINGER JOHN F. JONES LEONARD SEGLIN a, Add W2. PM

United States Patent 3,375,175 PYROLYSIS 0F COAL Ralph Tracy Eddinger, Princeton Junction, and John F. Jones, Princeton, N.J., and Leonard Seglin, New York, N.Y., assignors t0 FMC Corporation, New York, N.Y., a corporation of Delaware Filed Jan. 21, 1965, Ser. No. 426,812 8 Claims. (Cl. 201-31) ABSTRACT OF THE DISCLOSURE Increased yield of oils and tars are obtained from the pyrolysis of coal by conducting the pyrolysis in at least three fluidized stages, the first being carried out under oxygen free conditions below the fusion temperature of the coal by sufliciently high temperature to remove about 140% volatiles from the dry coal, conducting the. so treated coal to at least a second stage to remove nearly all the volatiles from the coal, and to a final stage to substantially devolatilize the coal, and recovering the condensables from the overheads of the stages.

This invention resulted from work done under Contract 14-01-0001-235 with the Oflice of Coal Research in the Department of the Interior, entered into pursuant to the Act establishing the Oflice of Coal Research, 30 U.S.C. 661 668.

This invention is concerned with the pyrolysis of coal, and its principal aim is to provide a process for pyrolysis of coal which will insure the production of maximum amounts of liquid hydrocarbonaceous products from the coal.

The economics of coal production is very largely related to. geography, other things being equal. Coal that can be mined cheaply is valuable or not, depending on whether it or its. conversion products can be readily transported to points. where. it. can be used. As a result, there are huge deposits of coal which are capable of inexpensive mining which have relatively little commercial. value, because they are remote from the point of usage; whereas liquid fuels such. as petroleum, because these can be transported by pipeline to refineries or ports and cheaply transferred to tankers. for economic transportation to the using point, are not so limited by geography.

One obvious way of converting coal at the mine to a form in which it is readily transportable is to build a power plant at the mine and transport the electrical energy produced therefrom to markets by transmission lines. Unfortunately, in some areas. where coal is available there is no water available for such a plant. Moreover, some deposits are in areas Where hydroelectric power is abundant, so there. is little economic. incentive to utilize the coal in this fashion.

Another and more flexible approach would be the. provision of some simple process for converting the coal either to liquid or a combination of liquid, combustible gas, and solid in. such proportion that the liquid would be in a high enough proportion to the solid to transport it as a slurry in a pipeline.

Even the partial. realization of this possibility will require very considerable increases in the yields of oily ice liquids over known methods of low pressure pyrolysis of coal. Experimental methods are known which yield as much as 20% of the weight of the coal as condensable liquid; the known commercial methods only yield about 10%. Hydrogenation at high pressures (above about 500 p.s.i.g.) can be used to increase the yield, but is too expensive.

Ideally the yield of liquid hydrocarbons should approximate at least the yield of residual coke. However, any increase in liquid yields is of considerable value since it reduces the amount of residual char which cannot be transported by pipeline along with the oil which is moved with it Moreover, it has been noted that as the yields of oil from a coal are increased, the percentages of polynuclear aromatics are reduced, so that the oils from the coal should become more useful as a possible feed stock for the manufacture of products competitive with those obtained from petroleum. This is not surprising since it is believed that petroleum and coal merely represent two different products resulting from the fossilization of organic matter.

The instant invention has as its principal object the provision of a process for pyrolyzing various ranks of coals, and particularly various bituminous and subbituminous coals to produce maximum yields of liquids vis-a-vis the solid residues. The method as applied to bituminous coal has produced maximum yields of about 24% to 25% for high volatile B bituminous coals and yields of 25% to 32% for high volatile A bituminous coals.

According to the present invention, we heat finely divided coal in a series of at least three fluidized beds to progressively higher temperatures under conditions which maximize the yield of liquids. In the first stage the finely divided, preferably dry coal, is introduced into a fluidized bed maintained at a temperature just below the temperature at which fusion of the mass sufiicient to defluidize the bed would occur, for a short residence time sufficient to reduce the weight of the moisture-free coal about 1% to about 10%, in the absence of added oxygen. The overhead from this stage is sent to a condenser where liquids are condensed out. This removal of volatiles raises the fusion temperature of the residue, which can thus be overflowed into a second fluidized bed at a higher temperature, where more of the volatiles can be removed in the absence of added oxygen, and this, in turn, be passed into a. further stage(s) where the remainder of the volatiles can be removed. Oxygen should be omitted in all but the very last stages of the process, until after about all of the condensables have been removed. Pressures are low, from atmospheric up to about 500 p.s.i.g.

It is essential to the successful operation of this process that the fiuidizing gas passing through the first stage of the process be free of vapors from the following stages. This is because this stage of the process is the most delicate, and the condensation of the oily material from the vapors from the later stages would cause a lowering'of the fusion point of the mass and consequent loss of'fiuidization.

In the later stages of the process the vapors from succeeding stages can be passed through. the previous stages to insure better heat utilization and all of the overheads can be recovered, preferably after being. combined with the overhead from the first stage.

The number of stages needed for any coal to avoid loss of fiuidization in any stage is dependent on the amount of volatiles in the coal and the tendency of the coal to fuse. Thus a typical Illinois No. 6 Seam coal, which is classified as a high volatile B bituminous coal, can be successfully procesesd in 4 stages, while a Pittsburgh Seam coal, which is classified as a high volatile A bituminous coal, will require 6 to 8 stages.

The number of stages needed for any coal can be substantially lowered by recycling char at a relatively low ratio of recycle to process coal (of the order of 2 to 1, to 3 to 1) to the second and subsequent stages. Recycle to the first stage is unnecessary to prevent agglomeration, and is undesirable because of problems in bringing very hot recycle char into contact with fresh coal. Recycling will, for example, reduce the number of stages needed for a high volatile B bituminous coal from 4 to 3 and make it possible to process a high volatile A bituminous eoal in as little as stages.

The temperatures used in the various stages depend, of course, on the nature of the coal, and particularly on its fusion point. In general a dry high volatile bituminous coal will fuse up in a fluidized bed at about 630 F. to 700 F., so that a temperature of 600 F. to 650 F. depending on the particular coal involved leaves an adequate margin of safety, while being high enough to start the evolution of oil forming vapors which is essential in this stage to permit transfer of the coal to the next higher stage. Low volatile bituminous coals can be heated up to 800 F., whereas high oxygen subbituminous coals can be heated as high as 850 F. in this first stage. Such low volatile coals cannot produce high yields of liquids, although our process does increase the oil yields over k n-own processes.

It is most surprising that the removal of relatively small amounts of volatiles-of the order of as low as 1% to l0%permits the next stage of the process to be run at :a temperature as much as 200 F. higher than the temperature in the first stage.

Heretofore it has been considered necessary to oxidize the coal in this stage, in order to permit the use of substantially higher temperatures in the next stage. This is most undesirable for the production of high yields of oily liquids, since oxidation not only prevents oily liquid from being recovered overhead in this first stage, but markedly reduces the yield in subsequent stages. The removal of small amounts of volatiles in the first stage accomplishes the same purpose as oxidation, but apparently by an entirely different mechanism. It seems likely that the lowest molecular weight, and hence the lowest melting of the volatiles in the coal, are driven off first, so that a substantial increase in fusion temperature is obtained with a very small weight loss, so that substantial increases in temperature can be made in the succeeding stage, especially with high volatile B bituminous coals.

This is less so in the case of high volatile A bituminous coals, which apparently contain higher percentages of low molecular weight material. With such coals it is necessa'ry-to proceed more cautiously, even with char recycle.

Use of oxygen in the intermediate stages, as in the first stage, will reduce oil yields. Apparently the hydrogen in the coal hydrocarbon matrix, which is essential for the oil production, is oxidized at a somewhat faster rate than carbon. Hence, internal heating by adding oxygen to the fiuidizing gas should be reserved for the final stage, in which the feed contains very little volatiles recoverable as oil.

The process can be best understood by reference to the accompanying drawings, in which:

FIG. 1 is a flow sheet of our process as applied to one high volatile B bituminous coal, without char recycle.

FIG. 2 is a flow sheet of our process as applied to one high volatile A bituminous coal, with char recycle.

Referring to the drawings, FIGURE 1 discloses the preferred mode of operation with high volatile B bitumi- 4 nous co als. The coal is first crushed to a size desirable for fiuidization, generally minus 14 mesh, and is fed into a first fluidized bed where it is maintained at a temperature sufiiciently below the fusion temperature of the coal to prevent the mass from fusing, but sufficiently high to remove substantial quantities of volatiles in addition to unbound water. In high volatile bituminous B coals, this range is from about 600 F. to 650 F. Fluidization is by means of an inert gas, preferably hot flue gas, which both heats and fluidizes, although external heating may be used. About 1% to 10% of the weight of the dry coal is removed overhead during a residence time of from about 1 to 30 minutes; of this overhead, about half represents material conden'sable to oily hydrocarbon liquids.

The dried preheated coal is then fed into the second stage, in which the first pyrolysis occurs, where it is immediately heated to a higher temperature, but below its raised fusion point, to start driving off the bulk of the volatiles. The fiuidizing medium is, for the sake of heat economy, the overhead from the third stage, and consists of gas plus condensables from that stage. Residence time is from 1 to 30 minutestemperature about 800 F. to 900 F. The second stage overhead includes all the gas and condensables from the coal, excluding that which came out of the drying-preheating stage. In general, there is enough condensable hydrocarbon to yield a total of about 24% to 25% oily liquid by weight in the original dry coat. The amount of gas produced is a function of the way in which the fourth stage is operated, and can be varied from about 10% to 30% by weight of the original coal. Residual char (from the fourth stage) will vary from about 35% to 60% by weight of the original coal, reflecting both the treatment in the last stage and the ash level in the original coal. Alternatively, the fluidizing medium may be any inert gas, and external heating may be used. But it is essential to avoid oxygen feed into this stage if high oil yields are to be attained.

The partially devolatilized char from stage two goes into a third stage in which further fluidized bed pyrolysis is carried out, at temperatures of the order of 950 F. to 1050 F. The fluidizing medium is preferably the overhead from stage four. After 1 to 30 minutes in this stage, the char contains little more than a percent or so of volatiles which are recoverable as liquid condensates.

The char from stage three is fed into a fluidized calcination bed maintained at a temperature between 1500 F. and 1800 F., by internal combustion of the char by the gas fed into the reactor as a fiuidizing medium, which may be air or oxygen. The overhead goes into stage three to act as a fluidizing medium. It may contain a very small amount of condensables; otherwise its constituents are dependent on the amount of oxygen in the fluidizing gas, and total residence time in the bed, these two factors together controlling the temperature and the composition of the gas discharged. We prefer to operate at residence times of from 1 to 30 minutes, and with high oxygen concentrations, to get about 1600 F. in the bed, and an exit gas with high concentrations of hydrogen and carbon monoxide.

Example 1 In order to determine what goes on in each of the individual stages, the process was operated with the stages independent of each other, using nitrogen as the fluidizing medium, as an experimental expedient, in all the stages. The coal used was a high volatile bituminous B coal from the Illinois No. 6 Seam-Orient No. 3 Mine; on a dry basis it contained 34.6% volatile matter, 58.8% fixed carbon and 6.6% ash; ultimate analysis 74.9% carbon, 4.9% hydrogen, 1.8% nitrogen, 1.1% sulfur, 10.7% oxygen, 6.6% ash. The fluidized bed reactor was an externally heated stainless steel cylinder, 3 inches in diameter and 30 inches high. Thirty pounds of coal were fed to stage 1, and the underfiow from each stage was fed to the next stage, under the conditions indicated in the following table, to give the results there indicated:

TABLE I.-FOURS'IAGE PYROLYSIS OF AN ILLINOIS NO.

6 SEAM COAL (ORIENT NO. 3 MINEl Stage 1 Stage 2 Stages Stage 3 Stages Stage 4 Stages land2 lto3' 11:04

Operating Conditions:

Feed Rate, lb./hr 4. 3.0 3. 0 8.0 Fluidizing Gas Rate (N2),

t't./sec 0.6 0. 6 0.6 0 6 Avg. Bed Temperature, F. 600 850 l, 000 1,600 Balances:

Overall 99 97 97 96 Carbon 103 98 105 99 Yields, wt. percent, dry basis:

Ch 83. 0 81.8 78. 6 64. 2 88.8 57.1 12.0 12. 9 11. 7 22. 5 1.8 23. 6 3.8 3.8 2.3 5.7 0.6 6.1 1.2 1.5 7.4 7.6 8.8 13.2 26. 7 28. 7 26. 0 50 4. O 53 The experiment was repeated, using hydrogen as the fiuidizing gas throughout; overall gas yield was about 8%, oil yield about the same as for the run with nitrogen, char yield about 61%.

When the process is run continuously as shown in FIGURE 1, using hot flue gas, overhead from stage 3, overhead from stage 4, and oxygen as the fluidizing gases, char yield is lowered to about 50%, oil yield is increased to about 25% and gas yield is substantially increased. Moreover, the proportion of hydrogen in the gas is increased, so that it may be used to react with the oil, in known fashion, to reduce its viscosity, so that it is easier to pump.

High volatile A bituminous coal is much more susceptible to fusion, so that five or six pyrolysis stages would be needed between the first preheating stage and the final calcination-gasification stage if agglomeration were to be prevented. The necessary number of stages can be reduced by blending the product from the first preheating stage with from 1 to 3 parts by weight of recycle char from a later stage of pyrolysis. A typical flow sheet of such a process is shown in FIGURE 2. Oil yields are of the order of 25% to 32%; gas yields are from to 35%; and char yields are from 30% to 55%.

Example 2 A run was made as in FIGURE 2, using a high volatile A bituminous coa.lPittsburgh-Seam, Federal Mine. The coal was fed into the 3 inch unit above described, at the rate of 4 pounds per hour, using 640 F. in the first stage; 740 F. in the second stage, with 2 parts of recycle char from stage 4 added to 1 part of product from the first stage; 810 F. in the third stage, with an additional 1 part of char per part of first stage product; 950 F..in the 4th stage; and 1600 F. in the final stage. The overall yield from the coal was Percent Char 45.6 Oil 27.5 Aqueous liquor 7.0 Gas (CO free) 14.0 CO 5.9

In general, conditions can be varied as shown in the drawing, using temperatures from 600 F. to 650 F. in stage 1, 700 F. to 800 F. in stage 2, 750 F. to 950 F. in stage 3, and 950 F. to lO50 F. in stage 4, depending on coal fed, rates of feed and other variables. Moreover, by adding more stages, less recycle is needed in the various pyrolysis Stages.

Example 3 Char recycle can be used with Illinois No. 6 coal to reduce the total number of stages to three. Using the identical coal and apparatus used in Example 1 with nitrogen as the fluidizing means, coal was fed to a first stage at 650 F., at a rate of 4 pounds per hour, until about 2.6% of volatiles were lost. This discharge was mixed held fluidized with nitrogen, until a total of about 22% of the condensable oil had been removed; it was then fed to a calcination stage at 1600 F., again fluidized with nitrogen, to recover the rest of the volatiles. Total yields were 54.7% char, 24.1% oil, 7.1% aqueous liquor, 11.2% combustible gas and 2.9% CO Ranges of yields for the various products are essentially the same as for the conditions shown in FIGURE 1.

It should be noted that when recycle of char is used in our process, we do not exceed a char to feed ratio of more than three to one. The use of high ratios of recycle markedly reduces the throughput of the process, and sharply afiects the overall economy. The very low ratio of recycle is made possible by the pretreatment in stage one, where the very significant increase in fusion temperature is attained by the relatively slight removal of condensable vapors overhead.

Obviously, changes can be made in the above examples, which can be multiplied indefinitely, without departing from the scope of the invention as defined in the claims. The invention is notonly applicable to high volatile bituminous A and B coals, where yields of 25% and more of oils are obtainable, but it will increase the yields of oil from other ranks of coal over known low pressure pyrolysis processes.

We claim:

1. In the process of pyrolyzing finely divided coal at low pressures in which the coal is heated in a plurality of fluidized beds at successively higher temperatures to devolatilize the coal, the method of increasing the yield of oily liquids recoverable from the coal which comprises (1) in a first stage heating the finely divided coal below its fusion temperature under oxygen-free conditions in a first fluidized bed formed by passing an inert gasiform stream upwardly through the stage to maintain the coal in the fluidized state until about 1% to about 10% of the coal volatiles have been removed .r'as overheads and recovering oily liquids from said overheads,

(2) in at least a second stage passing the so-treated coal into at least one other fluidized bed which is fluidized by the gaseous overheads from the subsequent stages at a temperature above that of the first bed and below the fusion point of the solids fed to that stage, under oxygen-free conditions, for a time sufiicient to remove nearly all of the volatiles from the coal condensable to oily liquids,

(3) in a final stage passing the thus-treated coal into a final fluidized bed which is fluidized by an oxygencontaining gas at a still higher temperature, to substantially devolatilize the coal, and

(4) recovering the oily liquids from all stages subsequent to the first stage from the overheads of the second stage.

2. The process of claim 1, in which one part of the treated coal from the first stage is introduced into the second stage, mixed with up to three parts by weight of hot product from a stage beyond the second stage.

3. In the process of pyrolyzing a high volatile bituminous B coal in which the finely divided coal is heated in a plurality of fluidized beds at successively higher temperatures to devolatilize the coal, the method of increasing the yield of oily liquids recoverable from the coal to the range of about 25% of the Weight of the dry coal, which comprises (1) in a first stage heating the coal to a temperature of about 600 F. to 650 F. under oxygen-free conditions in a first fluidized bed formed by passing an inert gasiform stream upwardly through the stage to maintain the coal in the fluidized state until about 1% to about 10% of the coal volatiles have been removed as overheads and recovering oily liquids from said overheads.

(2) passing the thus-treated coal into a second fluidized bed which is fluidized by the gaseous overheads from the subsequent stages at a temperature of 800' F. to 850 F., under oxygen-free conditions for a time sufficient to remove substantial amounts of volatiles from the product,

(3) passing this partially pyrolyzed product into a third fluidized bed which is fluidized by the gaseous overheads from the subsequent stages at a temperature of 950 F. to 1050" F., under oxygen-free conditions, for a time suflicient to reduce the remaining volatiles in the coal condensable to oily liquids to no more than about 1%,

(4) passing this pyrolyzed product into a fourth fluidized bed which is fluidized by an oxygen-containing gas maintained at a temperature of 1500 F. to 1600 F., to substantially devolatilize the char, and

(5) recovering the condensables from the overheads of all stages subsequent to the first stage from the overheads of the second stage. i

4. The method of claim 3, in which oxygen containing gas is fed into the fourth fluidized bed to react with the char to provide heat, and the overheads are fed counter" currently to the third and second stages to heat them.

5. In the process of pyrolyzing a high volatile bituminous B coal in which the finely divided coal is heated in a plurality of fluidized beds at successively higher temperatures to devolatilize the coal, the method of increasing the yield of oily liquids recoverable from the coal to the range of about 25% of the weight of the dry coal, which comprises (1) in a first stage, heating the coal to a temperature of about 600 F. to 650 F. under oxygen-free conditions in a first fluidized bed formed by passing an inert gasiform stream upwardly through the stage to maintain the coal in the fluidized state until about 1% to about 10% of the coal volatiles have been removed as overheads and recovering oily liquids from said overheads,

(2) passing the thus-treated coal into a second fluidized bed of the type aforesaid at a temperature of 900 F. to 1050 F., under oxygen-free conditions, after mixing it with about twice its weight of recycle from the third stage for a time suflicient to reduce the volatiles condensable to oily liquids to no more than about 1%, of the original dry coal,

(3) passing the pyrolyzed product into a third fluidized bed which is fluidized by an oxygen-containing gas maintained at a temperature of 1500 F. to 1600 F. to substantially devolatilize the solids, and

(4) recovering the condensables from the overheads of all stages subsequent to the first stage from the overheads of the second stage.

6. The method of claim 5 in which the third stage is fluidized with an oxygen containing gas containing at least as much oxygen as in air, and in which the second stage is fluidized by means of the overhead from the third stage.

7. In the process of pyrolyzing a high volatile bituminous A coal in which the finely divided coal is heated in a plurality of fluidized beds at successively higher temperatures to devolatilize the coal, the method of increasing the yield of oily liquids recoverable from the coal to the range of about 25% to 32% of the weight of the dry coal, which comprises (1) in a first stage, heating the coal to a temperature of about 600 F. to 650 F. under oxygen-free conditions in a first fluidized bed formed by passing an inert gasiform stream upwardly through the stage to maintain the coal in the fluidized state until about 1% to about 10% of the coal volatiles have been removed as overheads and recovering oily liquids from said overheads,

(2) passing the thus treated coal after admixture therewith of 2 to 3 parts by weight of product from one )of the further pyrolysis stages into a second fluidized bed of the type aforesaid at a temperature of 700 F. to 800 F., for a time suflicient to remove substantial amounts of volatiles from the product,

(3) passing this partially pyrolyzed product into at least two more fluidized beds, of the type aforesaid, with a temperature in the latter fluidized bed of 950 F. to 1050 F. all under oxygen-free conditions, for a time sufficient to reduce the remaining volatiles condensable to oily liquids to no more than about 1%, of the original dry coal,

(4) passing the pyrolyzed product into a final fluidized bed which is fluidized by an oxygen-containing gas maintained at a temperature of 1500 F. to 1600 F., to substantially devolatilize the product, and

(5 recovering the condensables from the overheads of all stages subsequent to the first stage from the overheads of the second stage.

8. The method of claim 7 in which the final fluidized bed is fluidized with an oxygen containing gas containing at least as much oxygen as air, and all the beds other than the first and the last are fluidized with the overhead from the next succeeding bed.

References Cited UNITED STATES PATENTS 2,955,077 10/1960 Welinsky 201-31 3,047,472 7/1962 Gorin et al. 201-26 X 3,076,751 2/1963 Minet 201' MORRIS O. WOLK, Primary Examiner.

R. E. SERWIN, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,375,175 March 26, 1968 Ralph Tracy Eddinger et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Co1umn 3, line 6, "procesesd" should read processed COlUlIII'l 8, line 31, after "800 F." insert under oxygen-free condltions Signed and sealed this 30th day of September 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

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