US1907579A - Gas package - Google Patents

Description

G. C. QUELCH May 9, 1933.

GAS PACKAGE Filed Nov. 10, 1928 QOMPRESSED BAS 1 R|Ev comPRESSED STABLE SAS INVENToR feo/yea @Heidi BY MM M. ATTORNEY PGI-ASH" Patented May 9, 1933 UNITE TES ATENT FICE GEORGE C. QUELCH, OF OAKMONT, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO UNION CAR-EIDE AND CARBON RESEARCH LABORATORIES, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK GAS PACKAGE Application filed November 10, 1928.

My present invention relatos to making natural gas suitable for use With oxygen in a blow torch to preheat and cut metal and at the same time suitable for storage in tanks at very high pressure yet capable of use with standard reducing valves and regulating equipment. It must be free from Water or paraiiin vapors when stored in the pressur@J container and should be suitable When compressed to 2,000 pounds per square inch for storage purposes. Its B. t. u. content shouldI be as high as is practicable for free gas and its flame temperature high enough to eliect eiicient preheating of metal.

Natural gas as it comes from the mains, if compressed to 2,000 pounds per square inch would fail to meet these requirements because of the considerable amount of Water gas and paraiiu vapor which it carries and which would cause freezing and gumming at the valves when the gas is expanded through standard regulating apparatus.

By my present invention, I provide a means for and a method of treating natural gas which will not only free it from the undesirable parain and Water vapors but which Will permit the retention of all unobjectionable homologues in order that losses 1n the B. t. u. content of the gas may be avoided.

The apparatus used is extremely simple and the method may bea substantially continuous one which takes the natural as directfrom the mains, compresses 1t and charges it at the desired pressure directly into the pressure containers with most of the undesirable Water and para-ilin vapors removed.

An important feature of the invention and one which greatly simplifies the apparatus and speeds up the method is the use of drying agents in the compressed gas containers so that the nal drying occurs in the containers after the gas has been packaged ready for shipment.

Practically all of the natural gas distributed in the Pittsburgh district has been treated at relatively low pressures for the 'recovery of certain readily condensible fractions. The gas analysis after such treatment Serial N0. 318,413.

varies somewhat at different plants but may be said to contain thc following elements` at close to the general proportions listed:

Methane 84.7 to 87.4 Ethane 6.8 to 9.4 Propane 1.55 to 3.0 Butane 1.81 to 1.3 Pentane trace Nitrogen 1.6 to 3.2 Oxygen trace to .1

rIhe Water vapor content is around 2%, the iame temperature around `4200D F. and the B. t. u; per cubic foot in the neighborhood of 1125 to 1150.

If a gas having the above approximate analysis is compressed to 2,000 pounds per square inch and then expanded through the ordinary reducing valve, there Will be trouble at the valve. The Water vapor will freeze and the parailin vapor Will liquefv at the valve and the valve opening would be quickly completely blocked or rendered totally ineicient for effecting a continuous and regulable supply of gas. The compressed gas mixture would be unstable.

Part of the Water vapor and part ofthe condensible paraffin vapors can be removed by compression and subsequent cooling the natural gas from the mains, this removal being assisted by the aifinity of certain 'of the oil vapors for the lubricating oil .used in the compressors. rIhe condensed vapors may betrapped and drawn off With the Water vapors compressed out of the gas. Such a method, however, even when supplemented by the passage of the gas through chemical drying means is not suiiicientl'y eifective When carried out at commercially practicable pressures, say above 1500 pounds per-square inch to give a product which is usablewhen subsequently stored at 2,000 pounds.

In accordance with the present invention, therefore, I supplement the compressing, cooling and chemical drying method of gas treatment by a final chemical drying which occurs in the compressed gas container. Preferably this final drying is accomplished by the provision of a small quantity of caus-l tic potash in the gas container, such potash being preferably of Walnut size so that it may be readily introduced through the ordinary 5% inch valve opening in the container. I ind that after the gas has been partially dried by the successive steps of compression, cooling and chemically drying and then introduced into a tank containing the caustic potash at the pressure of 2,000 pounds per square inch, final drying Will occur in 24 hours producing a stable gas Which is sufficiently dry to be expanded through a nozzle and which has the calorific qualities necessary to produce the intense heat required for a cutting flame.

A peculiarity of the final drying medium, to-Wit, the caustic potash used in the pressure tanks, is the fact that a single small charge of such material, say about two pounds of it, will last for'years. Even though the tank which contains it be repeatedly Charged vvith gas, the potash retains its drying efliciency over "unexpectedly long periods of time.

From the foregoing general discussion of the invention, it `Will beu seen that one feature of my invention concerns a gas package consist-ing of a' gas at high pressure packaged in a pressure tank in the presence o a drying agent.

The invention from another aspect is concerned with a method and apparatus for treating natural gas to produce a suitable gas for storage at high pressures and which gas when mixed With oxygen Will-produce an eiicient cutting flame.

The invention may be more fully understood from the following description in connection with the accompanying drawing which is a diagrammatic lvievv showing the apparatus which carries out the process by taking natural gas from the mains and charging it in a highly compressed and part-ially' dried conditionintov a final gas package.

In this draWing-I'have used the reference numeral to designate a conduit adapted to deliver natural gas from the main to a triple stage compressor 11, 12 and 13 which compresses the gas to say about 1500 pounds per square inch, certain of the Water vapors in the' gas being liquefied and certain of the oil vapors being entrapped by the lubricating oils of the compressors. The highly compressed gas from the last compressor 13 containing a certain amount of condensate is then 'passed through a cooler 14 in which further condensation occurs. Water inlets and outlets for the cooler are shown at 14a, 1&5. From the cooler the gas and its entrainedv condensate pass through -a pipe 15 into a-pinging bottle 16, the lower end of-Whieh is equipped with a valve 18 tlgough whichcondensate maybe drained o Gas passes oil' :from the top of the pinger througl'i a pipe 21, which pipe delivers it into a stand-pipe 22. The upper end of: the pipe 22 discharges into the first of a pair of similar drying bottles or towers 23 adapted to contain a chemical dryingl agei'it, while the lower end oi" the pipe 22 is equipped. With a second drain valve 24 through which further condensate may be removed. The chemical drying agent used in the bottle 23 is preferably caustic potash 24, this pot-ash being approximately nut-size and being supported in conventional manner upon a screen. 2 5 Within the bottle. The bottle 23 may be surrounded by refrigcrating coils or other cooling jackets if desired. From the top of the drying bottle gas passes to the second similar bottle7 thence through a pipe line 26 to a header l1 from which the tanks 27 are filled. A' header outlet pipe 42 is coupled directly to the inlet valve boss 28 oi' the container. A valve 25ct is located in the line 2G; When the process is started valve 26a is closed until the compressor builds up a pressure of 1500 pounds in the system as shown by gauge 262). The Valve is then opened Wide enough to permit the compressor to force gas into the cylinder 27 at its rated capacity until the pressure therein reaches 2,000 pounds. At this time by closing the valve on one cylinder and opening the valve of the next one, gas is .directed into the second cylinder.

Prior to the application of the valve fitting 29 to the container 2", small amount of caustic potash 30 has been introduced into the bottom of the container through the valve opening 31. A couple ci. pounds of potash are ordinarily suilicicnt for the ordinary size tank. The potash is preferably of nut size so that it may be conveniently .introduced through the usual 3,4 inch valve opening 31.

Exactly what reactions occur in the. -various stages of the process have not been ac. curately determined. I do know, however, that the condensate which is tapped 'poil through the valve 18 consists of condensed Water vapors and condensed paraiiin-vapors mixed with a slight amount of the lubrieating .oil which has been carriedalong from the compressor. Apparently themostv eilicient condenser temperature is approximately 40" to 504 F. y

I alsov have discovered that gas passed through ali-apparatus such asthat described above at a pressure maintained at 1400 to 1500 pounds, or over, still contains an undesirable quantity .of water vaporand par.- a-iiin vapor when it enters the storage container, these constituents being 'sufficiently high to cause freezing at the valve if the gas were to he immediately expanded from the normal tank pressure, in the usual Way. Nevertheless, within 2.4 lhours from the in:

gno

troduction. of the gas into the container, the supplemental drying effected by the potash 30 seems to have substantially removed or rendered harmless such undesirable vapors and the is well suited for expansion in the regulating apparatus, without danger of freezing or clogging. As noted above, a single small charge of the caustic potash drier in the tank not only takes care of the first charge of gas but also repeated recharges, remaining efl'ective over a period of two years or more. This action seems to be phenomenal and I can offer no entirely satisfactory explanation of it.

I have found that even though the gas at 1500 pounds pressure or over is passed through, a long series of drying towers containing caustic potash, drying is still incomplete, yet I am apparently able to obtain substantially complete drying by letting the gas stand for 24- hours at. 2,000 pounds pressure in the presence of a small amount of caustic potash, whereas passing it through an indefinite series of drying towers containing the same material is insufficient to produce my remarkable results.

This might lead to various theories, as, for instance, that the drying action of the potash is dependent not so much on the surface which is exposed to the gas, but upon the time of exposure. It is obviously iinpracticable to reduce the rate of gas flow through the apparatus to such an extent that the gas would remain stagnantly in contact with the drying agent over a long period of time. Another possibility is that the potash acts as a mechanical, molecular or chemical storage reservoir, taking care of the freezing constituents while the tank is at full 2,000 pounds pressure and giving off some or all of them when the pressure has fallen to a point where freezing temperatures are no longer produced by the expanslon.

By using some of the drying agent in the container, both of the difficulties are overcome either by complete drying or by the above suggested temporary storage of the freezing constituents.

I believe that the time factor and the pressure factor are both important in so far as the complete dr ing is concerned, but it is possible that i the gas direct from the nal drying tower were simply stored in a large reservoir in the presence of caustic potash, similar effects might eventually result, but it would take a very long time at the low pressures which would be practical in a large reservoir.. Such method would also be objectionable in that it would involve recompressng of the gas whereas the present process permits the gas from the mains to be compressed and forced right through the a paratus and into the final shipping containers.

I claim l. As a new article of manufacture, a package includin a transportable storage and service tank having an outlet valve fitting, a gas within the tank divested of all but a relatively small percentage of condensible vapor such as paraffin, moist-ure and the like and under relatively high compression and a relatively small amount. of solid chemical gas drying agent in the tank.

2. As a new article of manufacture, a package including a transportable storageand service tank having an outlet valve fitting, a stable gas within the tank divested of all but a relatively small percentage of'condensible vapor such as paraffin, moisture and the like and under a pressure of the order of 133 atmospheres and a relatively small amount of solid chemical gas drying agent in the tank.

3. As a new article of manufacture, a package including a transportable storage and service tank having an outlet valve fitting, natural gas having most of its moisture and paraffin content removed, said gas being charged into the tank divested of all but a relatively small percentage of condensible vapor such as paraffin, moisture and the like and under high pressure in the tank and a relatively small amount of solid chemical gas drying agent in the tank.

4. As a new article of manufacture, a package including a transportable storage and service tank having an outlet valve f1tting, a stable gas Within the tank divested of all but a relatively small percentage of condensible vapor such as parafiin, moisture and the like and under a pressure of approximately 2000 pounds per square inch and a relatively small amount of solid chemical gas drying agent in the tank, the gasdrying agent comprising lump material of sufficiently small size for introduction through the valve fitting opening.

5. As a new article of manufacture, a gas package including a transportable storage and service tank, a stable gas Within the tank divested of all but a relatively small percentage of condensible vapor such as paraffin, moisture and the like and of a character which will produce a cutting flame when mixed with oxygen, the gas being at a pressure of approximately 2000 pounds per square inch and a relatively small quantity o-f caustic otash in the bottom of `the said service tan 6. As a new article of manufacture, a gas package including a tank, a stable gas within the tank divestedv of all but a relativelyl small percentage of condensible vapor such as parafiin, moisture and the like and of a character which will produce a cutting flame when mixed with oxygen, the gas being at a pressure of approximately 2000 poundsl per square inch and a relatively small quantty of caustic potash in the bottomz-f the ank,i-the p'otash being @of ,applfoxinaely Walnut szefso #that it may lbe :Conveniently introdilcedi-thmugh the -val've bt/ing open- 5 ing of the tarkpr-inr `L0 the: application vf the :'vlve'A fitting.

'-Sgnekat Ve'ifmm,l inthel county of Allegheny, land; 'State f vzPennSylvania this 7th -iss er,y AND. 1928.

GEORGE o

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