GASEOUS WAVE PRESSURE REGULATOR AND ITS ENERGY RECOVERY SYSTEM Background of the Invention This invention involves a gaseous wave pressure regulation device which employs gaseous wave systems created by the pressure energy of a regulated pressurized gas stream. Through this device, the invention is designed to recover the energy from the regulated pressure drop into the form of heat and add this portion of recovered energy to the pressurized gas stream regulated during the pressure regulation process to compensate or eliminate the temperature drop effect spontaneously. Its application is intended for a pressure energy recovery system in natural gas liquefaction plants, natural gas distributing regulation stations, and relative petrochemical industrial processes where the pressure regulation is needed to meet the operating requirement of pressure conditions with unexpected temperature drop during the pressure regulation processes. In contrast with all prior arts for pressure regulation processes, the present invention reutilizes the energy between pressure drop, which is wasted in conventional pressure regulation devices, to create the periodic gas resonant flow and wave interactions so that a heat effect is generated in flow fluctuation conditions (either pressure drop or flow rate). This device is thus called a gaseous wave pressure regulator (GWPR). By entirely operating under the unique mechanism, GWPR can recover the pressure energy loss in traditional pressure regulators which are now widely used in a variety of industries.

The present device can find a wide range of applications in the various industrial fields for pressure regulation process. For instance, in petrochemical industries, numerous pressurized gas regulating processes are involved in process operations of condensation, separation, liquefaction, pressurized gas stream delivering and redistributing, liquid gas vaporization and combustion, gas stream refining and distilling, etc. In other industrial fields, pressure regulation process is also an essential part of the (give some example in a sentence).

No matter what pressure regulating processes are involved, generally speaking, all are operated under the specific pressure conditions in order to meet two fundamental goals, i. e., 1) the optimization of the system performance and 2) maximization of

production. Pressure regulation processes are defined here as the common measure to adjust the operated system in different pressure stage and accomplish the system operating in the proper condition. From the point of view of thermodynamics, all the pressure regulating processes are for two main purposes: (1) to obtain cooling effect which is generated by the temperature drop from the pressure drop, and (2) to adjust pressure level which fits the proper pressure operating condition for the optimized performance of systems. The former is achieved by using either the pressure energy extracting devices such as gas expanders, or Joule-Thomson effect, such as throttling valves etc., between the pressure drop. The latter is completed only by using pressure regulation valves, so called pressure regulators, to regain the energy loss in such processes.

However, the current pressure regulating devices are all limited by some fundamental imperfections in their operation mechanism. The main difficulty to utilize this portion of pressure energy with devices normally involves the mechanical moving parts which reduces the reliability of system operations. As a result, in the normal industrial practice, this part of pressure energy is simply wasted because the current pressure regulating devices cannot recover the energy and maintain the simplicity and reliability of the operating system at the same time.

More specifically, in the pressure regulating processes, pressurized gas streams undergo in essence a steady Joule-Thomson processes (J-T effect) to reduce the pressure level without heat and work transfer. The portion of energy in pressure drop is entirely dissipated in pressure regulators. As a result, pressure regulation processes result in the energy loss between the pressure drop and the temperature change. This is due to the internal energy reduction and entropy increment which depends on the operating condition. The temperature effect along with the pressure drop is generally represented by the Joule-Thomson coefficient defined by <BR> <BR> T<BR> 8 p) h to represent the change in temperature due to a change in pressure at constant enthalpy.

For a temperature increase during the pressure regulation, the JouleThomson coefficient

is negative; for a temperature decrease, the Joule-Thomson coefficient is positive. Most of pressurized gases used in the industrial system are imperfect gases with the higher inverse temperature above atmosphere, except for hydrogen and helium gases. Therefore, it is very common that a temperature drop accompanied with the pressure regulation processes in pressurized gas streams can be observed in the most of industrial systems.

Unfortunately, all the current pressure regulating devices cannot work without generating this spontaneous temperature drop which is unexpected in the pressure regulation processes and not allowed by the processes operation. The consequence of the temperature drop in the industrial processes can be very serious. It will lead to the reduction of production or lower system efficiency.

Usually, in order to overcome this inefficiency, the additional processes are required to eliminate this temperature drop to reduce cost in the operation and maintenance. For instance, in the natural gas industry supplying natural gases from gas fields are delivered by the pipeline under a high pressure level higher than the operating condition of LNG operating plant and commercial residential area in the consideration of economical transportation. Before the supplying gas steam enters the utility network or LNG plants, a pressure regulation is required to reduce the stream pressure. A typical process diagram between gas supply pipe and LNG operating plant is shown in FIG 1.

As shown in FIG 1, before entering LNG plant, supply natural gas has to pass through the several pressure regulators to reduce the pressure level. This is necessary in fitting the pressure operating condition either to the LNG plant to be liquefied or to the residential distribution system. In both cases, the range of pressure drop passing the pressure regulator is around AP 300-700 pis, which is significant pressure energy loss. On the other hand, since the pressurized gas stream reduces its temperature after the regulation, it results in two undesirable consequences to affect the LNG or gas distribution operation. Firstly, for the stream entering the LNG plant, some components of light hydrocarbon and water contained in supplying pressurized gas stream will become partially vaporized. Malfunction in the operation of dehydrated devices, such as molecular seize and absorbers in the early stage of LNG plant, will reduce the LNG production and affect the reliability of system operation. Secondly, for the stream distributed into residential system, the pressure drop between the distribution stations

and supplying pressurized stream is so great that it will result in the partial condensation of light hydrocarbon components.

As a result of these two consequences, condensed light hydrocarbon components in the distribution pipeline will reduce the heat value of natural gas, and temperature drop leads to the regulator being rusty in the summer and fully iced in the winter season, since the vapors in atmosphere are condensed and accumulated on the regulators. In order to overcome the problem resulted by the temperature drop within the necessary pressure regulating processes, usually, in LNG industrial practices, additional heating devices, such as oil burners or electric heaters, are used to reheat the supplying pressurized gas stream after it passed through the pressure regulator. It is very clear from this example that since the flowing volume heated is so great and the fuel or electricity cost to operate the reheating process is so huge, the amount of pressure energy loss is extremely significant.

Similar processes with double cost in both pressure energy waste and additional reheating bill attached to pressure regulations can also be found in other industrial processes and systems. For example, in LNG vehicles, electric cars with fuel cell system, and rocket engine used in the space shuttle, where liquefied gas is stored as fuel in a high pressure level in order to obtain the high temperature at the dew point-in all these cases, energy is lost and expenses increases.

Unfortunately, since pressure regulation methods and devices are so widely used in a variety of industrial processes, during the last few decades, a great deal of efforts concentrated on the device performance based on the development of new technology without addressing the problem of energy loss and the negative consequence of temperature drop in the pressure regulator. In all previous arts, the progresses and improvements have been focused on the mechanism design and controllability of pressure regulators to fit in with the specific operation condition and processes, as were employed by U. S. Pat. Nos. (5810029,5797425,5787925,5740833,5697398,5657787, 5507308,5458001,5402820,5392825,5131425,5047965,4974630,4974 629,4971108, 4966183, 4874011, 4840195,4817664,4811755,4757839,4684080,4679582,4606371, 4546752,4503883,4332549,4111222,4067355,4067354,3989060,3971 410,3845780, 3841303,3773071,3698425,3675678,3665956,3648727,3623506,3580 271).

Before discussing the issue of energy loss in the traditional pressure regulators, a brief summary in the previous arts seems necessary so that the significance of the present invention can be viewed more clearly.

In U. S. Pat. No. 5810029, an anti-icing design is provided for a gas pressure regulator to prevent normal pressure regulator device from icing used outside gas pressure regulator, which has a pressure vent and a downwardly opening vent tube associated with a skirt connected to and swTounding the vent tube. In this art, the mechanism design prevents rain or freezing rain from splashing back upwardly into the passage. In U. S. Pat. No. 5797425, a three-stage gas pressure regulator is provided in which a supplementary pressure regulator is used with conventional single or multi-stage pressure regulators with a novel two stage balanced pressure regulator to form a three-stage vacuum demand pressure regulation system in order to regulate the pressure of compressed gases used as fuel in engines, such as natural gas used in natural gas powered vehicles, especially useful in mono-, bi-, and dual fuel engine applications.

In U. S. Pat. No. 5787925, a pneumatically served gas pressure regulator is accomplished providing a relatively wide range of gas flow rates with precision outlet pressure control with a dome loaded gas pressure regulator and a pressure sensor controller integrated in a single unit. In U. S. Pat. No. 5740833, a two stage gas pressure regulator with a body housing having a gas inlet and a gas outlet, and a common interior wall dividing the body housing into two chambers forming two pressure reducing stages is given to accomplish the multi-stage regulation of pressurized gas stream. In U. S. Pat.

No. 5697398, a method of manufacturing a diaphragm assembly for a fluid pressure regulator is introduced, including a disk for regulating the flow of fluid through an orifice, a valve stem attached to the disk. In U. S. Pat. No. 5657787, a gas pressure regulator is designed consisting of a body member which mounts a valve between the inlet and outlet gas passages, and also a tubular sleeve which communicates with the outlet passage. In U. S. Pat. No. 5507308, a gas pressure regulator is introduced with a piston, a hollow rod, a high pressure chamber, an internal chamber, and coacting with a valve seat. This invented regulator is useful in respiratory equipment for divers, particularly for divers in cold water.

U. S. Pat. No. 5458001 is a gas pressure regulator and a diaphragm assembly which enables the precise alignment of a diaphragm and a valve carried thereby with respect to a valve seat for improved regulator performance. U. S. Pat. No. 5402820 is a stabilizer for fluid pressure regulators enhancing regulator stability without affecting the regulator capacity. U. S. Pat. No. 5392825 uses a gas pressure regulator for regulating the output pressure of a gas from a pressurized gas cylinder, including a flashback assembly disposed at the gas outlet of the pressure regulator to reduce the possibility of migration of a flashback upstream from the torch and hose into the pressure regulator. U. S. Pat. No.

5131425 represents an improvement in a gas pressure regulator. It has an inlet, an outlet, a gas flow passage, and a regulator mechanism in the valve body, including a relief valve which is set to open when the pressure of the gas in the flow passage exceeds a predetermined pressure.

In U. S. Pat. No. 5047965, a microprocessor controlled gas pressure regulator provides an adjustment of a gas regulator valve, having a spring based diaphragm controlled pilot valve which is automatically affected by supplying augmenting pressure to the spring side of the diaphragm via an electrically adjustable regulator valve under the control of a local microprocessor. In U. S. Pat. No. 4974630, a gas pressure regulator with a throttle valve is introduced in which the throttle valve has a sealing plug comprised of a needle and a base float fluidically drafted for closing a truncated cone hole of the throttle valve. U. S. Pat. No. 4974629 is a gas pressure regulator for saving a resetting operation, which includes a throttle valve provided between a gas inlet passage having an orifice formed therein and a pressure sensing chamber pertaining to a gas exit passage.

Scanning over the previous arts within U. S. Pat. No. 4971108,4966183, 4874011,4840195,4817664,4811755,4757839,4684080,4679582,4606 371,4546752, 4503883,4332549,4111222,4067355,4067354,3989060,3971410,3845 780,3841303, 3773071,3698425,3675678,3665956,3648727,3623506, and 3580271, it can be concluded that all pressure regulators introduced here have the similar mechanism: they use regulating pressure to adjust the pressure level by throttling pressurized gas stream in the configured chamber or passage, even though they may used in dissimilar controlling manners (diagram, mechanical level, actuators, etc.) specialized for specific operating conditions and industrial applications.

Obviously, the prior patents have made significant improvements and progresses in terms of a pressure regulator for manipulation and controllability, but none made significant improvement on the purpose of utilizing and recovering pressure drop energy from pressure regulation processes. None of previous arts have made the contribution on the design of a pressure regulator to reduce or eliminate the spontaneous temperature effects undesirable and harmful to some industrial processes and systems, associated with the pressure regulating operation. Although there are several forms of pressure regulators used for pressure drop regulation processes in prior patents, there was hardly any type of regulator which can be used as a pressure energy recovery device during the regulating pressure drop to reheat the pressurized gas stream and to increase the stream temperature as well. Therefore, the limitations and incapacity of the previous arts have given rise to the significance of the present invention in offering a solution to the energy loss problem in the regulating process.

By contrast with the traditional pressure regulation method and devices aforementioned, the present invention, for its primary object, introduces a method and a device using mechanism of gas wave interaction during the pressure regulation processes to recover pressure drop energy. The said method and device for pressure regulation in the present invention transfer the pressure drop energy from the regulated pressurized-gas stream back into heat effect inside the device by reheating the pressurized-gas stream after pressure regulation to compensate the spontaneous temperature drop. The applicant's apparatus will provide a steady effective operation based on such special operating mechanism of oscillation flow. In its turn, the flow is produced by compressible gaseous waves driven by the pressure drop energy in a designed structure for such an aim to effectively recover pressure energy dispersed in pressure regulation without involvement of any mechanical moving parts. Such a method and the present invented device is especially suitable for special technical processes in energy and chemical industries where the pressure drop regulation of providing pressurized gases stream is needed but the spontaneous temperature drop is unacceptable or harmful for the system operations.

Therefore, the present invention using the gaseous wave pressure regulating method is able to provide an effective method for the industrial processes to regulate the

pressure operating condition and to recover the pressure drop energy loss without the negative temperature drop effect. With a view to such a purpose, the present invention aims at meeting several important objectives of its industrial application.

The first is to provide a gas wave pressure regulation method and apparatus to replace the traditional pressure regulators to meet the requirement of operating conditions of the industrial system without the undesirable temperature drop.

The second is to provide a gas wave pressure regulation method and apparatus for petrochemical industries to recover the high pressure drop energy from the conventional pressure regulation processes and reuse the recovered energy in the form of heat in the systems to compensate the energy loss in the source to elevate the pressure level of pressurized gas stream.

The third is to provide wave pressure regulation method and apparatus for LNG operating plant to be used in the supply gas inlet where the pressure regulation is needed to adjust the supplying pressure fit to the pressure condition of the operation plant and to avoid using the additional reheating equipment.

The fourth is to provide a gas wave pressure regulation method and apparatus for natural gas regulating station between supply gas pipeline and residential network to reuse the waste pressure drop energy during pressure regulation processes to avoid the light hydrocarbon condensation, regulator damage by icing, or rust due to the temperature drop with the pressure regulation.

The fifth is to provide a gas wave pressure regulation method and apparatus for the LNG fuel vaporized system in LNG vehicle to recover the pressure energy from vaporization processes of LNG fuel and increase the engine efficiency by reheating gas fuel before combustion generated from the recovered pressure energy.

The sixth is to provide a gas wave pressure regulation method and apparatus for the fuel vaporized system of liquid gaseous fuel for rocket engines to increase the engine's efficiency by increasing the temperature of injecting gas fuel before the vaporized fuel enters the combustion chamber.

The last objective is to provide a gas wave pressure regulation method and apparatus with an energy recovery system which is able to operate under extreme high pressure drop condition by means of a multi-stage operation of the gaseous wave

regulation device in a series to recover the pressure drop energy into the form of heat to be recycled.

With these and other objectives in view, as will be apparent to those skilled in the art, the present invention resides in the combination of parts set forth in the specification and is covered by the claims appended hereto.

Summary of the Invention In general, the apparatus in the present invention, gaseous wave pressure regulator (GWPR), being a core part of the pressure energy recovery system in the present invention, comprises a flow buffer chamber which induces the pressurized gas stream, a chamber covering housing which holds the nozzle plug and pin-rod used to adjust the pressure level of regulation processes, a nozzle or nozzle set which renders a stable high speed jet or high speed jets through depressurized gas stream being regulated, a resonant tube or bundle of resonant tubes which supports the gas column oscillation with high frequency, a reheating unit in which the heat generated released by gas column oscillation is absorbed after the depressurized regulation process and is returned to the depressurized gas stream, and an outlet housing chamber which stabilizes the depressurized gas stream after the reheating and pressure regulation.

The pressure energy recovery system itself in the present invention consists generally of several gaseous wave pressure regulators combined with heat exchangers in series, by which the pressure drop energy is converted into the form of heat through each of gaseous wave pressure regulator, and released in the form of heat in the heat exchanger following the GWPR. The maximum of pressure energy recovery is achieved by controlling the pressure drop through each GWPR. Each stage of said energy recovery system comprises a GWPR and a heat exchanger. The GWPR uses the pressure energy throttled in pressure regulation processes and reheats the depressurized gas stream itself after pressure regulation, and the heat exchanger is used to reheat depressurized gas stream and to release the heat energy to another source by the heat exchanging.

Brief Description of the Drawings

The characteristics of the present invention, may be best understood by reference to one of its structural forms illustrated by the accompanying drawings in which : FIG. 1 is a side exploded view of the GWPR for high flow volume rate, FIG. 2 is a side exploded view of the GWPR for low flow volume rate, FIG. 3 is a schematic view of the pressure energy recovery system using GWPR of the present invention.

Detailed Descriptions of the Preferred Embodiment FIG 2, FIG 3, and FIG 4 best describe the general features operating mechanism and structure of a GWPR in the present invention, which primarily consists of a flow rate controlling unit of pressurized gas stream, a flow induction unit, and a pressure energy converting unit. Said flow rate controlling unit comprises a handwheel 1, a spindle 2, a covering housing 3, a nozzle plug 5, nozzle pin-rod or pin-rods 6, a nozzle or nozzles 7, fattened bolts 15, a packing gland 16, a bushing 17. Said pressure energy converting unit comprises an oscillating chamber 8, a conduit disk 9, a resonant tube 10 in GWPR 23 of FIG 4 or a bundle of resonant tubes 10 in GWPR 25 of FIG 4, an outlet chamber 11, a body housing 12, a reheating unit 13, flow control plates 14. Said flow induction unit comprises an inlet conduit 14, a buffer chamber 4.

FIG 4. best shows the corresponding pressure energy recovery system resulted from the GWPR in the present invention which comprises a GWPR 18 with a lower volume rate for high pressure level, a primary heat exchanger 19 connected to said high pressure GWPR 18, a GWPR 20 for high volume flow rate at the lower operating pressure level which is connected to primary heat exchanger 19, and a secondary heat exchanger 21 which is connected to the outlet of said low pressure GWPR 20.

Referring to FIG 2, FIG 3, and FIG 4, the outlines of the GWPR 18 and 20 are indicated, in which the body housing 12 is covered by the covering housing 3 with a nozzle adjusting mechanism consisting of the handwheel 1, the spindle 2 with the partial section of a thread, associated with the sealing parts of GWPR comprising the packing gland 16, and the busing 17, which functions the sealing around the cylindrical surface of the spindle 2 in order to prevent the leak of pressurized gas stream inside the buffer chamber 4 from GWPR operating environments. The said buffer chamber 4 connected to

the said inlet conduit I from the direction of side wall which forms a stream passage leading the pressurized gas stream into said buffer chamber 4. The said nozzle 7 separate said buffer chamber 4 which is at the primary high pressure level from loA pressure level reached by the pressure regulating operation. Following the said nozzle 7, a pressure energy converting unit in which the pressure drop energy is recovered during the regulating process, comprises the said oscillating chamber 8 where the jet rushed out of said nozzle 7 undergoes a underexpansion process and forms a normal shock wave system inside the jet, the reheating unit 13 which includes the conduit disk 9, the resonant tube 10 in GWPR 18 or the bundle of resonant tubes 10 in GWPR 20, combined with several flow control plates which are connected together before the outlet chamber 11. In essence, when a pressurized gas stream enters into the GWPR 18 or 20 undergoing a pressure regulating process, it at first flows through the inlet conduit 14 where the stream is led to the buffer chamber 4. After entering the buffer chamber 4, the pressurized gas stream drops its velocity, associated with the increment of static pressure, and reduces the turbulence and vortice in the pressurized gas stream by means of a flowing diffusion process. As the pressurized gas stream flows through the convergent nozzle 7, the portion of pressure energy carried in the stream is converted into the kinetic energy, and the stream velocity gradually increases. With the pressurized gas stream rushing out of the outlet of nozzle 7, a high speed free jet in GWPR 18 and high speed free jets in GWPR 20 are formed in the front of the oscillating chamber 8. At the down stream of oscillation chamber 8, the resonant tube 10 in GWPR 18 and the bundle of resonant tubes 10 in GWPR 20 are mounted in alignment with the nozzle 7 in GWPR 18 and the nozzles 7 in GWPR 20 with the distance away in the jet down stream. As a matter of principle of gasdynamics, when the pressurized gas stream flows through the nozzle 7 in GWPR 18 or 20, it undergoes an initial process of pressure regulation or reduction by throttling effects, where the total pressure of the pressurized gas stream is reduced within a small quantity range due to the wall friction and the increment stream entropy in the nozzle 7. The velocity of pressurized gas stream reaches the maximum value in the throat section of said nozzle 7 (which equals sound speed), which is located in the exit if a convergent nozzle is used. As the jet passes the throat section where either is inside the nozzle 7 for the nozzle with a convergent-divergent passage or at the exit of

the nozzle for the convergent nozzle, it experiences the second stage of pressure regulation or reduction caused by the underexpanding jet passing the shock wave systems. During this stage, as contrasted to the process that the gas stream passes the conventional pressure regulator, the energy of pressurized gas stream is dissipated partially by the strong jet shock wave systems so that it will result in the high entropy generation in the gas stream. The rest of pressure energy is retained in the form of kinetic energy which is carried with the jet flowing. After the underexpanding jet entering the oscillation chamber 8, the significant portion of energy carried in the high speed jet or jets is released in GWPR of the present invention. In contrasted with the GWPR in the present invention, this portion of energy in the pressure regulators reported in the previous arts can not be dissipated, and the pressure level will be partially elevated as the depressurized gas stream goes through the enlargement section-passage in the downstream chamber. It is very clearly that the generation of pressure reduction in conventional pressure regulation devices is due to the energy dissipating processes at the initial throttling stage. Hence in the conventional pressure regulator, the pressure regulation must be achieved inside the designed narrow flow passage which provides a high friction and throttling processes to compensate the pressure recovery effect in the downstream of regulators. Such a process in the conventional pressure regulator usually causes the temperature drop and pressure energy wasting in the pressurized gas stream.

In the present invention, the portion of kinetic energy which is not dissipated in the conventional pressure regulator employed in the previous arts, can be effectively dissipated in succession by periodic wave systems to generate the significant heat effect when the underexpanding jets interact with the resonant tube 10. The major portion of pressure energy can be recovered by reheating the depressurized gas stream at the downstream to compensate the temperature reduction which sometimes is spontaneously unacceptable in the LNG and other industrial systems. Hereby, this operating mechanism of gaseous wave pressure regulation and the art of design used in the present invention fundamentally differ to the traditional means used in the previous arts, and form the basis of the features of the present invention.

For more details of GWPR operation, again referring to FIG 2., and FIG 3., after through the nozzle 7, the underexpanded high speed jets are impinged on the open end of

resonant tube 10 in GWPR 18 and open ends of the bundle of resonant tubes 10 in GWPR 20 if the resonant tube or bundle of resonant tubes 10 is or are placed in the core region of underexpanded jets with the distance away from the exit of the nozzle 7.

During the impinging process between the underexpanded jet and gaseous column inside the said resonant tube 10, the normal shock wave will be formed in the front of opening end of resonant tubes 10. This normal shock wave appearing in the high speed jets of depressurized gas stream is interfered with the gas column inside resonant tube or tubes 10. The interaction between the jet and gas column during the impingement will generate strong pressure disturbances which propagate in the both directions along the jet: the upstream direction of the underexpanded jet and the downstream direction of gas column inside resonant tube 10. The pressure disturbances propagated on the upstream of jet will change the pressure condition simultaneously before and after the normal shock wave, and result in the variation of shock wave position to respond to the pressure fluctuation caused by the pressure disturbances. As a consequence, the normal shock wave formed in the impinging jet with the resonant tube will become unstable and move between the open end of resonant tube 10 and the exit of said nozzle 7 inside the oscillating chamber 8. On the other hand, the pressure disturbances propagated downstream into the resonant tube 10 will induce the gas column oscillation at the inherent resonant frequency of the resonant tube 10. Once the induced motion of the normal shock wave couples with the gas column oscillation mutually, the self-sustained oscillation of gas column inside resonant tube 10 will be excited, accompanied with the significant heating effect generated by the periodic compression of pressure wave moving and viscous friction of the wall inside the resonant tube 10. The kinetic energy carried by the jet after throttling process is converted into the form of heat and released from the wall surface of the resonant tube 10. Furthermore, this portion of heat energy can be recovered by leading the depressurized gas through the outside surface of resonant tube 10 after exchanging the kinetic energy with resonant tube 10. Actually, the depressurized gas stream after releasing its kinetic energy to the resonant tube 10 in the oscillation chamber 8, at first, will pass the conduit disk 9 in order to stabilize the stream and reduce the flowing interference to the impinging processes between the jet flow and resonant tubes 10. After passing conduit disk 9, the depressurized gas stream is conducted through several flow

controlling plates inside the reheating unit 13 by which the gas stream is conducted to flow over the surface of resonant tube or bundle of resonant tubes 10 in a serpentine manner. The heat exchange between the depressurized gas stream and the surface of bundle of resonant tubes 10 reheats the depressurized gas stream before it leaves the GWPR. After reheated, the depressurized gas stream enters the outlet chamber 11 to finish the pressure regulating process.

Again referring to FIG 4, the pressure energy recovery system using GWPR device as the core parts, is well illustrated, which comprises a GWPR 18 provided for the operation in low volume flow rate at a high pressure level, a high pressure heat exchanger 19, a GWPR 20 provided for high volume flow rate, and a low pressure heat exchanger 21. In the regulating process with a high pressure drop (Ap>300psi) which is the most common condition operated in conventional pressure regulators, the noticeable pressure energy is wasted by the dissipation of the throttling processing. The pressure energy recovery system in the present invention is designed to recover the pressure energy during high pressure regulating processes in industrial processes. The basic operation is described as follows: the high pressurized gas stream in the high pressure level, firstly, enters the primary GWPR 18 which is designed to handle a small flow rate in the high pressure level. After flowing through GWPR 18, the pressurized gas stream reduces the pressure by the expansion process which results in the volume increase.

Then, the gas stream enters the primary heat exchanger 19 in which the heat absorbed from pressure drop in the primary GWPR 18 is released to the recirculating coolant fluid passing through the shell of the heat exchanger 19. To fit the requirement of operating condition with a small volume rate in the high pressure level, the GWPR 18 is designed with the single nozzle 7 and resonant tube 10. Out of the primary heat exchanger 19, the gas stream experiences the secondary pressure regulation in the secondary GWPR 20 which is designed to handle the volume rate increase after the primary pressure regulation. Inside the GWPR 20, the pressure of gas stream is reduced further, and similarly the heat converted from the pressure drop energy is released inside the secondary heat exchanger 21. In the secondary heat exchanger 21, the recirculating fluid is reheated again, and the output can be reused in systems. In the present system, the pressure drop distribution between the two stages of the GWPR operation is very critical

to make the energy recovery efficiency, which is needed to selected carefully before the nozzle and resonant geometrical parameters is determined in designing.

Summarily stated, the GWPR will be operated under a pulsating flow production created by the interaction between the resonant tube and underexpanded jet, in which the self-sustained longitudinal oscillation of normal shock wave in the high speed jet due to the impinging interaction is coupling with the oscillation of gas column in the resonant tubes. The pressure energy wasted in conventional pressure regulators can be recovered in the form of heat created by resonant wave system in the present invention GWPR. By reheating the pressurized gas stream itself after pressure regulation, the present invention can overcome the drawback of unexpected temperature drop during the pressure regulation. From the GWPR experiments, it is shown that the pressurized gas stream can be reheated more efficiently if the internal energy loss is reduced during the longitudinal oscillation of gas column driven by jets. The geometrical parameters of nozzle, diameter of resonant tubes, the length of resonant tubes, and cross-section shape of resonant tube are very critical to influence the GWPR operations. The efficiency of pressure energy recovery is effected by operating conditions with those parameters which will result in that GWPR operates in different oscillating modes. Owing that the pressure energy is a high grade energy as the driven force in the GWPR operation, the effective operation of GWPR will be reached in the case that heating pump cycle can be driven by a resonant pressure wave system originated from the self-sustained oscillation between the jet and gas column. Hence, the pressure energy converted from high speed jet will not be directly dissipated by gas column oscillation and wall friction. The heat generated by resonant tube will be accumulated on the surface of tube. The internal energy loss of high speed jet to drive the gas column oscillation will be compensated by the heat effect generated by resonant tube and entropy increment in the jet underexpansion.