Method and apparatus for reducing costs and emissions from extracting and processing gas and oil from underground resources

Abstract

This invention relates to improvements in the current recovery of gases and oil liquids from an underground resource such as shale by means of hydraulic fracturing “Fracking.” The main improvements consist of increasing the yield of gases and oil liquids from drilled wells as well as eliminating the use of water which is a major problem. Mobile processing equipment, to upgrade the recovered resource and to convert it to a marketable product, is conducted where the resource is thermally extracted, resulting in the elimination of pipelines to conventional upgraders which produce an intermediate which is thence delivered by means of pipeline or rail to a far away conventional refinery. This new mobile approach which will be situated at or adjoining the drilled wells will lower capital and operating costs, reduce emissions, facilitate permitting, and help reduce public opposition to “Fracking.”

Description

This invention relates to improvements in current recovery of energy from underground resources such as gas and oil from shale, oil sands, coal, and the like wherein the resources are in a solid, semi-solid or gaseous state. A patent which deals with the recovery of energy from underground resources, which was issued to the Applicant on Aug. 23, 2011, titled “Method for Recovering Energy In-Situ from Underground Resources and Upgrading Such Energy Resources Above Ground” bearing patent No. U.S. Pat. No. 8,002,033 B2, is herein mentioned as reference.

BACKGROUND

Using the extraction and the processing of gas and oil from shale as example, the production and the processing of natural gas and oil from shale comprises-three steps: Upstream production, Midstream processing, and Downstream refining; there are serious challenges in all the three steps.

With respect to the Upstream step wherein horizontal directional drilling and hydraulic fracturing, or “Fracking,” are utilized, water mixed with sand and chemicals is injected underground to cause the release of natural gas and oil liquids from the shale resource. Despite the large quantities of water used, the major disadvantage from this practice which occurs, is the very poor percent yield recovery of the gas and liquids from the wells when compared to that which is left behind (see Exhibit 1(a), bottom paragraph, page 1). Reference is also made to Exhibit 1(b) wherein the first paragraph states the following: “From 2004 to 2012 the development of shales was basically, hit it with a big sledge hammer and see what comes out.” It surely is indicative that a better extraction process is sorely needed. The other disadvantages are:

• (i) Excessive use of water (3 to 6 million gallons per well) containing additives;
• (ii) Contamination of the water; (iii) Use of settlement ponds to contain polluted materials; (iv) Disposal of contaminated water into deep wells by way of injection;
• (v) Increase in operating costs; and (vi) Substantial local public opposition to Fracking.

With respect to the Midstream (processor) step, the disadvantages are: obtaining pipeline right-of-way from landowners together with the capital investment requirement for the pipeline installation from the wells to connect with the processor and the large investment in the processor itself which is immobile.

With respect to the Downstream step, the costs incurred to have the upgraded products produced in the Midstream step being delivered by pipeline or by train to a refinery in the case of the liquid to be refined, and by liquefaction followed by separation in the case of the natural gas. In addition, there are environmental issues such as the formation of residuum and sludges which must be disposed in special, costly sites. These costs do not even include the cost of the refining operation itself.

In summary, shale drilling in the United States faces major hurdles that Create expensive infrastructure and transportation issues to get shale gas and liquid from the extracted well to the processor and thence to the consumer by way of a refinery, while confronting a low market price for natural gas.

OBJECTIVES

The main object of the present invention is to improve the yield from the drilled wells in order to increase the value of the underground resource.

Another object of the instant invention is to extract from underground additional resource in the form of gas and/or oil from abandoned drilled wells and from current poor-yielding drilled wells by means of the improved extraction technology described herein to result in producing lower-cost gas and/or oil in an environmentally acceptable manner.

Still another object of the instant invention is to completely eliminate the use of water, sand, and chemicals to fracture the resource in the well and instead, to extract gases and vaporized liquids in the form of “volatile matter” produced underground by means of a clean, recycled hot gas, with said extracted volatile matter being brought above ground inclusive of said recycled gas; this step consists the Upstream portion of the invention.

Further still another object of the instant invention is to continuously clean said volatile matter to produce a clean synthesis gas from which a relatively small side-stream is taken from the clean synthesis gas, which is cooled, compressed, and heated above ground, to continuously serve as the newly formed recycle gas to be continuously injected into the well to result in creating a most efficient extraction method of underground raw gases and liquids, simulating the devolitilization of coal wherein only 1% of volatile matter (V.M.) is left in coke when coal is pyrolyzed into coke; see Exhibit 2.

Yet another object of the present invention is to pass the raw volatile matter comprising the mixture of gases and vaporized liquids immediately after being brought to the surface, through a hot sorbent in the form of pellets (Exhibit 3(a) and 3(b)) at the well site or nearby, in order to produce a clean synthesis gas by cracking and desulfurizing said raw volatile matter into a clean main stream of synthesis gas (syngas), thus eliminating the need of utilizing a pipeline to connect the wells to the processor in Midstream's present practice which can extend a distance of scores or even hundreds of miles from the wells.

Therefore another object of the present invention is to direct the balance of the main stream of syngas to be synthesized into methanol which is converted to gasoline in close proximity to the wells site in order to produce a product for delivery to market by means of tank trucks directly to retail gasoline stations, thus providing the efficient access of a low-cost transportation fuel to consumers.

It is further another object of the instant invention is to make possible the integration of the production, processing, and refining by means of mobile equipment that can be sited at the vicinity of the wells to perform the production, processing, and refining of the resource originating from underground reserves, to result in producing a marketable product in condition to be marketed to the consumer.

It is still another object of the present invention to reduce capital and operating costs in the production, processing, and refining of gases and liquids from underground resources by means of mobile equipment that is adaptable for highway transport that can be sited adjacent to the extraction wells, and physically make it possible to move from a group of exhausted wells to another group of freshly drilled wells or abandoned wells containing reserves which conventional Fracking practice was not capable to extract.

It is yet another object of the instant invention to provide environmentally benign facilities which will facilitate permitting.

The above and other objects of the present invention will become more apparent to those skilled in the art to which this invention pertains from the description hereinafter disclosed.

Reference is now made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in various views. It is to be understood that the embodiments shown herein and the phraseology used herein are for the purpose of description and not limitation. Other embodiments and phraseology may be used without departing from the spirit of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flow diagram of the invention called “THERMO-YIELD”; it illustrates the steps as well as the components to achieve the above-referenced objects and by way of example uses the recovery of resources from underground shale followed by processing it and refining it into methanol which is converted to gasoline.

FIG. 2 represents the mobile trailer which contains the compressors to pressurize the recycle gas to the appropriate injection pressure and the heater that raises the temperature of the recycle gas.

FIG. 3 represents the mobile trailer for the electric power generator and the office where the controls for the entire operation are housed.

FIG. 4(A) shows the top view of the mobile trailer that contains the Cracker-Desulfurizer reactor to upgrade the raw gases and liquid oil, and FIG. 4(B) is the same Cracker-Desulfurizer reactor, except it is shown in front elevation. These two figures show the Cracker-Desulfurizer reactor in the reclined position which is used during its being transported from one well site to another well site.

FIG. 5(A) illustrates the front elevation of the Cracker-Desulfurizer reactor in the upright position, with FIG. 5(B) shown in the side upright elevation. This upright position is used when the Cracker-Desulfurizer reactor is in the process of simultaneously cracking and desulfurizing the recovered raw gases and the oil liquids to convert them to a clean synthesis gas (hereinafter referred to as syngas) containing H₂ and CO.

FIG. 6(A) represents the mobile trailer with its operational equipment in front elevation and FIG. 6(B) in side elevation for the separation of the syngas from the methane and for the conversion of the syngas into methanol by way of synthesis, with the reactors being in the upright position.

FIG. 7 represents the mobile trailer with the MTG (methanol-to-gasoline) conversion vessel situated below the degassing vessel, with both being in the upright position.

FIG. 8(A) and FIG. 8(B) represent the gasoline finishing mobile trailer with its operational equipment shown in the upright position, with FIG. 8(A) being in the front elevation and FIG. 8(B) being in the side elevation.

FIG. 9 illustrates a fleet of three mobile trailers hitched together with a tractor being the prime mover for transport on roads and for delivery from one well's site to another, with the proper equipment to accomplish the extraction and upgrading.

FIG. 10 illustrates a fleet of three mobile trailers hitched together, with a tractor being the prime mover for transport on roads which serve for the refining step which comprises the conversion of syngas into methanol and the production of crude gasoline from the methanol, and the crude gasoline being finally finished into a gasoline suitable for direct delivery to consumers.

FIG. 11 illustrates the three mobile trailers situated side by side in the vicinity of the well(s) to perform the extraction and the upgrading.

FIG. 12 illustrates the three mobile trailers situated side by side to perform the refining into marketable product which, in this case is marketable gasoline ready to be delivered to gas stations.

FIG. 13 shows the gasoline delivery truck.

FIG. 14 shows gasoline being delivered by truck to the gas station to service customers by means of commonly used pumps.

DETAILED DESCRIPTION OF DRAWINGS

Referring to FIG. 1, numeral 10 represents the underground resource and numeral 11 the injection pipe of the hot recycle gas. Numeral 12 represents the heater which heats the recycle gas; this heater may take one of various configurations such as an induction heater which is shown in this FIG. 1, using electric power, as the source of energy. Numeral 13 represents the cracker-desulfurizer which converts the resource brought to the surface into a synthesis gas (syngas), and numeral 14 is the sorbent regenerator. Numeral 15 is the methanol synthesis, 16 is the separator, 17 the degasser, 18 the MTG (methanol to gasoline) converter, and 19 comprises the gasoline finishing.

Referring to FIG. 2, it comprises the trailer, which is denoted by numeral 24, that houses heater 12 and compressors 20. FIG. 3 represents the trailer, which is marked numeral 25, that houses generator 21, control room 22, and office 23.

Referring to FIG. 4(A), numeral 27 represents a top view of trailer 26 containing cracker/desulfurizer 13 and sorbent regenerator 14, and FIG. 4(B) represents the same as FIG. 4(A) except it is shown in front elevation; both FIGS. 4(A) and 4(B) show the cracker/desulfurizer 13 and sorbent regenerator 14 on trailer 26 in the reclined position.

FIGS. 5(A) and 5(B) show cracker/desulfurizer 13 and sorbent regenerator 14, mounted on trailer 26, in the upright position. It is to be noted that cracker/desulfurizer 13 is connected to regenerator 14 by means of transition 28 forming a unitized vessel configuration denoted by numeral 30, with the sorbent regenerator 14 being above cracker/desulfurizer 13 with transition 28 in between. This unitized vessel configuration is housed in a structural cage marked by numeral 29 to which the unitized configuration is rigidly integrated within structural cage 29. A hoisting means marked by numeral 31, which may take the form of a hydraulic system, is capable of hoisting cage 29, about a pivot, within which the unitized vessel configuration 30 is housed, from a reclined (horizontal) position to an upright (vertical) position and lowering the same from the upright position to the reclined position on the bed of trailer 26, marked by numeral 32.

Referring to FIG. 6(A) which illustrates the equipment in front elevation; it represents trailer 45, with cage 29(a) housing vessel 34 and vessel 35, with vessel 34 situated above vessel 35, with vessel 34 serving as the methanol synthesis section, and vessel 35 serving as the syngas/methanol separation section. The connection between the vessels comprises a transition which is marked by numeral 37. As described in FIG. 5(A), a hoisting mechanism similar to hoist 31 is provided and marked by numeral 31(a) to accomplish the tilting action of cage 29(a) from a reclined position to an upright position and from upright position to the reclined position. The reclined position is the mode when trailer 33 is towed by tractor 38, and the upright position is the mode when the equipment is in operation. It is to be noted that FIG. 6(B) represents the side elevation of FIG. 6(A).

FIG. 7 illustrates the front elevation of the first part of the methanol-to-gasoline (MTG) portion of the process. It consists of a vessel denoted by numeral 39 forming the lower part of cage 29(b) where the methanol is converted into gasoline (MTG), and the upper part marked by numeral 40 represents the degassing vessel with a transition marked by numeral 41 being situated between vessel 39 and vessel 40. The tilting of cage 29(b) is effected by hydraulic system 31(b).

Referring to FIG. 8(A), it illustrates the finishing vessel for producing marketable gasoline, marked by numeral 42 and housed in cage 29(c), which in turn is mounted on a trailer denoted by numeral 47. The hoisting of cage 29(c) is effected by hydraulic system 31(c) which is adapted to raise cage 29(c) from the reclined position to the upright position and from the upright position to the reclined position. FIG. 8(B) represents the side elevation of FIG. 8(A).

Referring to FIG. 9, it represents a first mobile fleet denoted by numeral 44 comprising three trailers marked by numerals 24, 25, and 26 which relate to extracting and processing, termed “Upstream” together with “Midstream,” in condition to transport equipment from one location to another location. FIG. 10 represents a second mobile fleet denoted by numeral 45 comprising three trailers marked 46, 47, and 48 and relates to converting syngas into methanol, thence to marketable gasoline, termed “Downstream,” and in condition to transport equipment from one location to another location. Both FIGS. 11 and 12 illustrate that the fleets at the vicinity of drilled wells have been delivered and are being prepared for the operation of extracting, and upgrading by the equipment shown in FIG. 11, and refining by the equipment shown in FIG. 12.

Operation

Reference is now made to FIG. 1 to describe the operation in detail. To initiate the operation, a gas such as propane gas (LPG) is used as recycle gas until steady state is attained. Once steady state is attained, pumps 61 direct the extracted gases and liquids to the top of cracker/desulfurizer 13, marked by numeral 49 by way of pipe 62 and discharged as clean gas from the bottom of the cracker/desulfurizer 13 at point 50, also marked by letter “A,” and directed to cooler marked by numeral 52 by means of pipe 51. From cooler 52, the cold, cleaned gas as a side stream “B” is delivered to a compressor marked by numeral 54, directed by means of pipe 53; thence by means of pipe 84 to induction heater 12 to raise the temperature of the gas in pipe 11 in order to generate a hot, pressurized recycle gas that is directed into the underground shale resource and injected by means of pipe 57 as a pressurized gas with minimum heat loss into the underground resource in order to efficiently heat the resource by way of pyrolysis. Injection pipe 57 is configured in such a way as to be located in the shale resource with a gas collection pipe 58 situated above injection pipe 57 and an oil liquid collection pipe 59 situated below injection pipe 57; a liquids collection reservoir 60 is provided to gather the oil liquids from the shale. The injection of the hot, pressurized recycle gas from pipe 57 causes the shale to devolatilize, releasing gases and liquids as experienced in making metallurgical coke. Hundreds of millions of tons of coal are pyrolyzed in the steel industry worldwide by means of heat, while very efficiently yielding gases and oil liquids. Extraction pumps marked by numeral 61 are provided to continuously bring the raw gases and liquids from the underground shale resource inclusive of the injected recycle gas which becomes part of the extracted raw gases. It is to be noted that a secondary side stream containing CO₂ is discharged from condenser 80 as stream “C” and is directed to compressor 54 to become part of hot recycle stream 57.

Once the raw gases and liquids are above ground, they are directed by means of pumps 61 and pipe 62 to the top of cracker/desulfurizer 13, where they are cracked and desulfurized by flowing co-currently through the hot catalyst in cracker/desulfurizer 13 to form a hot, clean synthesis gas composed mainly of 2H₂+1CO and possibly even 3H₂+1CO, depending upon the richness of the resource. This synthesis gas (syngas for short) exits from the bottom of the cracker/desulfurizer 13 at a junction point marked by letter “A.” Main stream 51, which feeds into cooler 52, is divided into side stream “B” marked by numeral 53 and main stream 64 which is boosted in pressure by compressor 55 becoming main stream “D”. With respect to CO₂, the source originates from the conversion of SO₂ into elemental sulfur, using CO as reductant. This CO₂ stream joins the hot recycle gas and both are heated by the induction heater 12 and are directed from above ground by means of conduit pipe 11 to the underground resource and injected into the resource at high temperature with the thermal energy contained in the hot recycle 1 gas. Since there is carbon in the resource, the CO₂ reacts with such carbon to form 2CO.

Side stream “B,” denoted by pipe 53, is compressed by compressor 54, raised in temperature in heater 12 to become the hot recycle gas through conduit pipe 11 for injecting underground, and main stream 64 comprises the syngas (2H₂+CO) main stream “D” which serves as the feedstock that is ultimately converted into methanol and gasoline, both being marketable products.

Specifically, the “Downstream” procedure of converting the final marketable product of main stream “D” comprises the following steps:

Step 1. The syngas (2H₂+CO) stream 66 is synthesized into methanol by means of a methanolization process known in the industry, marked by numeral 15, producing a mixture of methanol and unreacted syngas which is fed as stream 67 into a separator marked by numeral 16.

Step 2. The methanol is separated from the unreacted syngas in separator 16, producing crude methanol as stream 68 and unreacted syngas which is marked by numeral 69. The crude methanol is directed to a methanol degasser marked by numeral 17, and the unreacted syngas is fed to collector 70.

Step 3. From degasser 17, the degassed methanol stream marked by numeral 71 is fed to the methanol-to-gasoline converter (MTG) marked by numeral 18, and the unreacted syngas is fed to collector 70 by means of stream 72.

Step 4. From MTG converter 18, the crude gasoline is fed to gasoline refiner 19 by way of stream 73 where it is finished into a marketable product, with the unreacted gases being directed by means of stream 74 to collector stream 70 to be recycled. The two products leaving gasoline refiner 19 comprise stream 75 which is the marketable gasoline and stream 76 which is the propane (LPG).

A booster compressor denoted by numeral 85 is provided to pressurize the gases in collector 70. It is to be noted that in the event that collector stream 70 becomes too large a stream to be recycled by joining main stream 64, then collector stream 70 is directed to join stream 84, instead, by means of an auxiliary pipe which is not shown, becoming part of the recycle prior to being heated.

Referring to FIG. 13, a tank truck is represented and marked by numeral 77. It is common practice to deliver gasoline to service stations by means of tank trucks similar to truck 77. FIG. 14 is represented by a service station denoted by numeral 78 which is adapted to receive a truckload of gasoline and store the gasoline in underground storage tanks, with pumps above ground which serve the public.

It is to be noted that the instant invention may preclude the conversion of methanol to gasoline by virtue that methanol per se has several advantages when compared to gasoline, as described in Exhibit 6, which is titled “The Case for Methanol,” produced by EPA. Further, when compared to natural gas from the standpoint of NO_x formation, methanol produces only 36.3% of that produced by natural gas (45 ppm vs. 124 ppm) and when compared to fuel oil, methanol produces only 21.7% of NO_x (45 ppm vs. 207 ppm). There are parts of the United States that do use fuel oil for heating which can be replaced by methanol which can be lower in cost and cleaner than fuel oil. Methanol can also be used as a chemical feedstock, and since it is a liquid it can be stored in tanks rather than natural gas, which depends on its availability from a pipeline.

In conclusion, the method and apparatus herein disclosed offers an efficient, novel, economical, and useful approach to overcome the disadvantages currently experienced, which are enumerated in the BACKGROUND section of the instant specification that deals with present recovery, processing, and refining of gas and liquids from underground resources.

Claims

1. In a method for recovering gases and liquids from underground energy resources which are converted by three steps to result in producing marketable product or products ready for use by the consumer, wherein said steps comprise an Upstream activity which relates to extraction, a Midstream activity which relates to upgrading the extracted material into an intermediate, and a Downstream activity which relates to refining the intermediate to a product in condition to be marketable to the consumer, while said three activities take place at three different locations which are remote from one another such that the Midstream is many miles away from where the extraction takes place, necessitating a pipeline to connect the well(s) to the Midstream location and another pipeline or transport means such as a train to deliver the intermediate from the Midstream to the Downstream refinery, the IMPROVEMENT consisting of situating the Upstream activity and the Midstream activity substantially at the same location to result in obviating the continuous cost in the transportation of the raw gas and oil liquids between the Upstream location and Midstream location, as well as the time and cost of securing the rights-of-way between the Upstream and the Midstream for a pipeline which also requires continuous maintenance and liability with respect to pipeline ruptures, spills, and leaks.

2. The method as set forth in claim 1 wherein the Midstream activity which relates to upgrading and Downstream activity which relates to refining are situated substantially in one location to result in obviating the cost in the transportation of the upgraded intermediate between the Midstream and Downstream, when the intermediate is transported by pipeline or by rail from the Midstream location to the Downstream location.

3. The method as set forth in claim 1 wherein said Upstream activity, said Midstream activity, and said Downstream activity are situated in substantially the same location in order to save the transportation costs from the Upstream to the Midstream and from the Midstream to the Downstream, as well as to avoid maintenance of pipelines, including ruptures, spills, and leaks.

4. In a method for recovering gases and liquids from underground energy resources which are converted by three steps to result in producing marketable product or products being ready for delivery to the consumer, wherein said steps include an Upstream activity which relates to the extraction of such resource from drilled wells, which are spaced apart in close proximity to one another, the IMPROVEMENT wherein equipment to conduct the upgrading of said resource from said drilled wells is effected by miscellaneous activities practiced by various pieces of equipment that can be set up and be operated in close proximity of the drilled wells, be dismantled when the yield from the wells drops or ceases, and be moved to newly drilled wells to be re-set and operated again on relatively short notice, in order to economically process said extracted resource into an intermediate that results in the elimination of a major pipeline that connects the drilled wells to the Midstream upgrading facility which is immobile, and such facility is located at a distance of scores of miles or even a hundred or more miles away from said drilled wells while incurring large capital investment, long time to permit, and long time to construct.

5. The method as set forth in claim 4 wherein said underground resources are upgraded by means of upgrading equipment mounted on towed trailers to give such equipment mobility in order to make possible the parking of said trailers in close proximity to said drilled wells.

6. The method as set forth in claim 5 wherein said upgrading consists of cracking and desulfurization of said resource above ground, producing a clean intermediate.

7. The method as set forth in claim 6 wherein said intermediate is refined, by means of refining equipment mounted on towed trailers to give such equipment mobility in order to make possible the parking of said trailers in close proximity to upgrading equipment.

8. The method as set forth in claim 7 wherein said intermediate is refined into marketable product or products being in condition to be delivered as finished product or products directly to consumers, resulting in the elimination of pipelines and/or rail transport which extend hundreds or even thousands of miles from upgrading equipment.

9. The method as set forth in claim 5 wherein said towed trailers are assembled as a fleet of trailers to be pulled by a tractor in order to transport such fleet to and from the vicinity of drilled wells.

10. The method as set forth in claim 7 wherein said towed trailers are assembled as a fleet of trailers to be pulled by a tractor in order to transport such fleet to and from the vicinity of upgrading equipment.

11. The method as set forth in claim 4 wherein said miscellaneous activities include the injection of a pressurized, hot recycle gas into drilled wells to cause the release of gases and liquids by means of thermal energy which results in efficiently increasing the yield of gases and liquids from said underground resource, in reducing extraction cost, and reducing emissions, particularly by avoiding water contamination and its disposal in wells.

12. The method as set forth in claim 11 wherein said recycled gas is heated by induction.

13. The method as set forth in claim 4 wherein said Upstream activity includes the cracking and desulfurizing of the extracted resource to convert it to an intermediate.

14. The method as set forth in claim 1 wherein said Midstream activity which relates to upgrading the extracted material into an intermediate is further characterized by said intermediate being a clean synthesis gas.

15. The method as set forth in claim 14 wherein said synthesis gas is converted to methanol.

16. The method as set forth in claim 15 wherein said methanol is converted to gasoline suitable for delivery to retail gasoline stations to service consumers.

17. The method as set forth in claim 1 wherein said Midstream activity which relates to upgrading the extracted material into an intermediate is further characterized by said intermediate being clean natural gas.

18. Apparatus for extracting and processing energy from drilled wells in the form of solid, semi-solid, liquid and gas, or a mixture thereof, comprising reaction vessels adapted to be transported on trailers for mobility to be situated in the proximity of said drilled wells in order to drastically reduce the need for pipelines, elimination of conventional immobile upgraders as well as conventional immobile refineries.

19. The apparatus as set forth in claim 18 wherein said vessels are adapted to articulate about a pivot in order to change positions from a reclined position to an upright position.

20. The apparatus as set forth in claim 19 wherein said vessels are adapted to upgrade gases and liquids into an intermediate when in the upright position and in a reclined position during,travel from one location to another location.

21. The apparatus as set forth in claim 20 wherein said intermediate is converted to a refined product by making use of portable vessels.

22. The apparatus as set forth in claim 18 wherein said vessels are interconnected when in operative mode under pressure.

23. The apparatus as set forth in claim 21 wherein said refined product is methanol by making use of portable vessels.

24. The apparatus as set forth in claim 23 wherein said methanol is converted to gasoline in portable vessels.

25. The apparatus as set forth in claims 20, 21, 23 and 24 wherein said vessels are connected to pressurizing equipment.