CA1294565C - Heating system with gas jet driven circulation flow for high pressure well head separator - Google Patents
Heating system with gas jet driven circulation flow for high pressure well head separatorInfo
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- CA1294565C CA1294565C CA 530483 CA530483A CA1294565C CA 1294565 C CA1294565 C CA 1294565C CA 530483 CA530483 CA 530483 CA 530483 A CA530483 A CA 530483A CA 1294565 C CA1294565 C CA 1294565C
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- gas
- separator
- burner
- heating
- heat exchange
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Abstract
ABSTRACT
A high pressure well head separator system having a circulation heating system with energy to circulate liquid heating medium between a heating unit and the separator provided by well gas injected into the heating medium by a gas jet. Gas injected into the heating medium is recaptured and subsequently burned by at least a gas burner pilot associated with a gas burner used for heating the liquid heating medium in the heating unit. A gas jet by-pass line is provided and variably controlled by a separator thermostat assembly.
A high pressure well head separator system having a circulation heating system with energy to circulate liquid heating medium between a heating unit and the separator provided by well gas injected into the heating medium by a gas jet. Gas injected into the heating medium is recaptured and subsequently burned by at least a gas burner pilot associated with a gas burner used for heating the liquid heating medium in the heating unit. A gas jet by-pass line is provided and variably controlled by a separator thermostat assembly.
Description
This invention relates to a natural gas well effluent high pressure separator system of the type employed at a gas well head to remove connate well fluids from a well effluent composed of a mixture of gas, oil and water and, more particularly, to a self circulating gas jet driven heating system for use with such a natural gas high pressure separator.
Examples of gas separating and dehydrating units are disclosed in United States Patent Nos. 3,094,574; 3,288,448;
4,342,572; 4,421,062 and copending Patent Application Serial No.
487,591 for FLUID PUMPING SYSTEM of Charles R. Gerlach and Rodney T. Heath. In general, such units comprise a separator means for receiving the gas-oil-water mixture from the well head and separating the oil and water liquids from "wet" (water vapor laden) gas; and a water absorber means, which employs a liquid dehydrating agent such as glycol, for removing the water JJ~
1~94565 vapor from the gas subsequellt to its passage through the separator and producing "dry" gas suitable for commercial usage.
Such well gas dehydration units may comprise two 05 separate glycol circulation systems. One glycol circulation system, sometimes referred to as the glycol heating system, circulates glycol throuyh a closed loop between a heating means such as a reboiler and the separator means in order to maintain the temperature in the separator at an optimum value for separating oil and water mixture from the well effluent. Circulation oL glycol in such a heating glycol circulation system is sometimcs provided by a thermosyphon flow produced by the temperature difference between the separator and the reboiler. ~nother glycol circulation system, sometimes referred to as the process glycol circulation system, is generally caused to circulate by a glycol pump. The process g~ycol is continuously supplied to the absorber means in a "dry" low water vapor pressure condition and is removed from the absorber means in a "wet"
high water vapor pressure condition. The wet glycol is continuously removed from the absorber means and circulated through a treater means which may include the reboiler means (which is also used to heat the heating glycol) and a sLill column, etc. for removing the absorbed water from the wet process glycol to provide a new supply of dry process glycol. The glycol reboiler means usually comprises a gas burner for heating the glycol therein. Since the separating/dehydrating units are continuously operated at well sites without continuous monitoring by operating personnel, reliable continuous operation of the glycol ...
:' ' .. i. ' ' S~i5 circulation systems is of critical importance. Because of the often remote location of wells, it is highly desirable to use energy sources readily available at a well site for operation of these circulation systems. Since the glycol heating system uses substantial amounts of energy it is of uptnost economic importance to operate this 5 system with maximum efficiency and minimum energy loss.
Although the use of a thermosyphon, such as described in Heath, U.S.
Patent No. 4,342,572, to product circulation in a heating glycol system is extremely energy efficient, a drawback of thermosyphon circulation is that it is relatively slow and thus limits the speed at which heat can be transferred to the separator by the 10 heating glycol system.
Another manner of producing circulation in a heating glycol system is through use of a gas jet pump as described in U.S. Patent No. 4,421,062 of Padilla Sr. In this arrangement, well gas, after passing through a series of drip pots and regulators which reduces the gas pressu~e to about 25 psi, is injected into a heating 15 glycol flow line which forms part of a closed loop system between a high pressure separator and a reboiler. The gas is injected through a nozzle structure directed toward the reboiler and induces a venturi effect on the glycol in the surrounding portion of the glycol flow line to produce upward flow thereof through a lift pipe portion of the flow line into the reboiler which consequently produces circulation 20 of heating glycol frorn an opposite end of the reboiler into the separator. A
relatively high circulation rate flow of JJ: 3 129~565 ileating glycol may be provided between the separator and the reboiler so long as gas is discharged through the gas nozzle structure. Gas flow to the gas nozzle structure is controlled by a thermostat in the separator which permits a 05 gas flow through the gas nozzle structure whensver the separator temperature falls below a predetermined value and which shuts off the gas flow to terminate the circulation of heating glycol whenever the separator temperature exceeds another predetermined value. Gas discharged from the nozzle structure into the glycol flow is subsequently collected in a scrubber housing above the reboiler tank and is thereafter discharged through a gas outlct line having a relief valve set at approximately 23 psi. The gas outlet line from the scrubber passes through another series of check valves and is connected to the burner and burner pilot. The burner is turned on and off in response to a control signal from a thermostat in the reboiler. Thus, some of the gas discharged through the gas nozzle structure to produce circulation of heating glycol between the separator and reboiler is available for use by the burner and burner pilot. A problem with this system is that a great deal of the gas discharged through the gas jet may of necessity be vented to the atmospllere during periods when the gas jet is operating without the burner firing. Thus, this system may waste considerable amounts of gas.
It would be generally desirable to provide a heating glycol circulation system for circulating heating glycol between a reboiler and high pressure separator which provides the extremely high energy efficiency of a thermosyphon heating system while providing the relatively . . .
l'Z945f~5 high speed circuLatioll capability of a gas injection type circulatiotl system without waste of valuable sale gas.
It would also bc desirable to provide a heating glycol system which continuously circulates heating glycol to a 05 separator at a rate which is dependent upon the current heat requirements of the separator.
Summary of the Invention The present invention provides a heating system for a high pressure separator which utilizes circulation of heating glycol between tlle separator and a heating means such as a reboiler for heating the separator. The heating glycol is heated by a burner and associated fire tube positioned in the heating means and fueled by natural gas from the well. In one embodiment, which is presently the best mode contemplated, a controllably variable portion of the natural gas which is ultimately used by a burner pilot is initially injected into the heating glycol circulation loop to produce glycol circulation. The maximum amount of gas which may be injected is dependent on the pilot burner gas collsumption rate, thus nonb of this injected gas must be vented to the atmosphere. A thermostatically controlled gas jet by pass line which allows a selectably variable portion of the burner pilot gas to by-pass the gas jet is opened and closed dependent upon the temperature in the high pressure separator. After gas is jetted into the glycol, it is recovered in a sealed gas collection area above the glycol in the heating means. Gas from other heating system operating components may also bc collected in the gas collection area. All of this collected gas is in fluid lZ94565 conununicatioll with and is ultimately burned by th burner pilot. Pilot gas which by-passes the gas jet communicates with the recovered injection gas either in the collection area or, preferably, downstream of the collection area near 05 the pilot burner inlet. The injection of gas into the heating glycol causes a jetting effect which transfers energy to the heating glycol and provides a circulation rate therein which is dependent upon the amount of gas injected.
The maximum circulation rate provided by this controlled gas injection is significantly yreater than that provided by a thermosyphon type circulation system. Thus, the capability of the heating glycol system of the present invention to deliver heat to the separator is considerably better than that of a thermosyphon type system, yet the energy consumption requirements of the system of the present invention are no greater than that of a thermosyphon typc system because all gas used to increase the heating glycol flow rate is later burned to heat the heating glycol.
Control gas for operating various separator controls may be provided from the same gas supply system used for gas injection into the heating glycol.
Thus, a heating glycol system having a controllable circulation rate with a relatively high maximum circulation rate i~ provided which uses energy sources provided at the well site very efficiently.
In a slightly different embodiment of the invention, a controlled amount up to a maximum amount of all of the burner gas as well as all the burner pilot gas may be initially injected into the heating glycol circulation loop.
Thus a considerably grcater amount of gas may be injected 5~5 throuyh the gas jet than in the previously discussed embodiment with a correspondingly greater maximum glycol circulation flow rate.
Thus, the invention may comprise a well effluent 05 separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature ranye for receiving well effluent and for separating said well effluent into a liquid component and a relatively liquid free gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator lS means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner mcans operatively associated with said heating means for heating said heat exchange liquid therein;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for enabling circulation of said heat exchange liquid between said heating means and said heat cxchange conduit means in said separator means;
g) operating gas supply line means for supplying well gas for heatiny and for operating various separator control systems;
5~i5 h) gas jet means in fluid communication with said operating gas supply line means for injecting gas into said circulation conduit means for producing circulation of said heat exchange liquid in said 05 circulation conduit means;
i) sealed gas recapture means for recapturiny substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in continuous fluid communication with said burner pilot means whereby yas collected by said gas recapture means is subsequently burned by said burner pilot means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner lS pilot means to by-pass said gas jet means;
k) whereby the circulation rate of said heat exchange liquid is variably controllable through control of the amount of gas injected into said circulation conduit means.
The invention may also comprise a well effluent separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a wet gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said 5~5 heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum 05 operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said llcat exchange liquid in said heating means;
e) gas operated burner pilot means l~r igniting said burner means;
f) circulation conduit means for providing circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply means for injecting gas into said circulation conduit means for circulating said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said yas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in fluid communication with said burner pilot means and with said burner means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner ., ~ ~
1~9~565 pilot means and said burner means to by-pass said gas jet means;
k) burner control valve means operatively associated with said main burner means for selectively controlling 05 the gas flow to said main burner means r l) heating means thermostat means operatively associated with said burner control valve means for controlling the gas flow to said burner means in response to the temperature in a selected portion of said heatiny means whereby said burner means is selectively operated to maintain the temperature in said selected portion of said heating means within said optimum operatiny temperature range;
m) whereby pressure energy from all gas in~ected into said circulation conduit means is used to increase the circulation rate of said heat exchange liquid in said circulation conduit means and whereby gas collected in said sealed gas recapture means is subsequently burned by said burner pilot means and said burner means and whereby the circulation rate of said heat exchange liquid is variably controlled through the amount of gas injected into said circulation conduit means, Brief Description of the Drawing Fig, 1 is a schematic drawing showing basic operating components of a circulating glycol heating system for a high pressure separator of the type used at a gas well head.
Fig. 2 is a schematic drawing showing a modification of the burner gas supply shown in Fig. 1.
`i: '~ ` ! ` .
12~45~5 Fig. 3 is a detailed cross sectional elevation view of a gas jet and a portion of the heating glyco] circulQtion conduit of Fig. 1.
05 Detailed Description of the Invention The well effluent separator system 10 of the present invention is adapted for use at a gas well head for processing well effluent to obtain dry sale gas therefrom.
The invention in general includes a high pressure separator 12 adapted to receive well gas 14 to separate and remove certain entrained liquids therefrom; a heating means such as a reboiler 30 which heats a supply of heating fluid such as heating glycol 17 in a riser portion 84 thereof; circulating loop 34 which circulates heating glycol between the reboiler 30 and separator 12 to provide heat to the separator; a drying assembly such as absorber 18 for drying well gas received from the separator 12 to produce dry sale gas 20;
and a burner assembly including a burner 31 and a burner pilot 32, used in combination with a fire tube 33 to heat glycol in the heating means. The burner means is fueled by gas wl-ich is supplied from the sale gas line leaving the absorber 18. At least a portion of the gas which is ultimately burned by the burner assembly is first injected by a gas jet 70 into the heating glycol circulation loop 34 z5 thereby transferring mechanical energy to the heating glycol to cause it to circulate. All of the gas injected into the heating glycol is subsequently recaptured and burned in the burner assembly. In one embodiment, Fig. 1, the recaptured gas is burned only by the burner pilot 32. In another embodiment, Fig. 2, the rccaptured gas is burned by both the ~: `
lZ945G~;
main burner 31 and the burner pilot 32. ~ reverse acting thermostat assembly 28 in tlle separator 12 is associated with a gas jet by-pass line 110. All of the gas supplied to the burner pilot, in the the embodiment shown in Fig. 1, 05 flows through either the gas jet line or the gas jet by-pass line. In the second embodiment of Fig. 2, all of the burner assembly gas flows through these two lines. The gas flow through the by-pass line increases, and the gas flow through the gas jet correspondingly decreases, with an increase in the temperature of the separator. The circulation rate of heating glycol varies with the injection gas flow rate.
Since the heating glycol is maintained at a nearly constant temperature, the amount of heat transferred to the separator by the heating glycol i5 dependent on the heating glycol circulation rate. The temperature in the separator is thus maintained near an optimum value through thermostatic control of gas flow through by-pass line 110 to control the injection gas flow rate which in turn controls the heating glycol circulation rate. Having thus described the invention in general, certain features of the invention will now be described in further detail.
High pressure separator 12 includes a well effluent inlet 13 whereat well gas 14 is received from the well head.
The gas passes through a demister ~not shown) which causes oils and other liquids to be separated from the well effluent. These liquids 15 from the well gas are collected in the lower portion of the separator and are heated by heating conduit 42 to maintain the temperature of the separator liquid near a preset optimum value. The separator liyuids 15 are periodically removed from the separator by 1~9~5~5 convent;onal dump valve arran~ements (not shown) as described in U.S. P~ent No.
4,342,572. Gas is discharged from the separator through outlet line ]6 to various conventional drying assemblies, such as described in U.S. Patent No. 4,342,572 and elsewhere, for further removing moist~lre from the gas. The drying assemhlies are collectively represented herein as absorber unit 18. Gas containing substantial amounts of water vapor is received at an absorber inlet 19 and dry sale gas 20 is subsequently discharged from the absorber outlet 21 to sale gas line 50. The absorber unit 18 utilizes process glycol to dry the well gas passing therethrough.
Dry process glycol 22 from the reboiler 30 is received at the absorber glycol inlet 23 and wet process glycol 24, which carries away moisture from the well gas, is discharged to the reboiler 30 from the absorber at process glycol outlet 25. Thewet process glycol from the absorber is partially dried in a still column 29 portion of the reboiler 30 and is thereafter stored in a process glycol tank 27 portion of the reboiler 30 where it is maintained at an elevated temperature by means of burner31 and associated fire tube 33. l he reboiler process glycol tank 27 and still column 29 form part of a c]osed loop glycol drying system (shown only partially herein)which is operated at atmospheric pressure. Such a closed loop glycol drying system is described in detail in U.S. Patent 4,342,572 of Rodney Heath entitled THERMAL CIRCULATION GAS TREATER.
Some of the sale gas 20 which is normally discharged to gas pipelines, etc. for subsequent sale, may be directed, as JJ: 13 ~r lZ~3~56S
by control gas supply line 51, back to certain system operating components for subsequent use at the well head site as described further hereinaLter.
~ heating glycol means which may be reboiler 30 is 05 heated by a burner assembly including a main gas burner 31 and associated burner pilot 32. The ~ain burner and burner pilot are assembled in a conventional fire tube 33. The fire tube 33 extends into the reboiler tank 27 contacting a supply of process glycol contained tilerein which in turn transfers heat to heating glycol 17 contained in a closed loop glycol heating system which includes a heating glycol storage area provided by a sealed expansion riser 84 portion of the reboiler 30. Heating glycol 17 in expansion riser 84 is sealed off from process glycol in reboiler tank portion 27 as described in further detail below. The heating glycol contained by the expansion riser 84 circulates through circulation loop 34 which passes through separator 12 and then returns to the expansion riser. Circulation loop 34 includes a reboiler conduit coil portion 36 which passes through a portion of the reboiler tank 27. The reboiler coil 36 terminates in the riser 84 at an open end 37 into which glycol 17 from the riser a4 flows to begin circulation through the heating glycol circulation loop 34. Ileating glycol in coil 36 is heated as it flows through coil 36 by the process glycol in tank 27. The reboiler coil 36 is connected to an upper circulation flow line 38 extending between the reboiler and separator 12. Flow line 38 is connected to separator heating conduit 42. Separator heating conduit 42 is connected to circulation return flow lZ~4565 line 44 whicll provides the return flow of heating glycol to the expansion riser 84 to complete circulation loop 34.
As mentioned above, a gas supply line 51 in communication witll the sale gas line from the absorber 18 05 provides gas used to operate certain system components. Gas entering line 51 is at a relatively high pressure, e.g. 500 psig, which varies irom well to well. Line 51 may comprise a control valve 52 therein enabling the supply line to be isolated from the sale gas line 50. A pressure regulator 54 is provided in line 51 which reduces the pressure in the downstream line portion 55 to a pressure ~0 which may be e.g. 75 psig. Line portion 55 communicates with a conventional drip pot 56 having a conventional relief valve 53 and drain line 59. Gas for burner and certain other system operations discharges from the drip pot 56 through line 57. Line 57 branches into three branch gas lines 58, 60 and 110. Branch line 58 leads to gas jet 70 with the gas passing therethrough being used to circulate heating glycol 17 and ~eing ultimately burned by burner pilot 32. Line 110 is a gas jet by-pass line which when open reduces the gas flow through line 58 by an amount equal to the flow through line 110. Gas flowing through line 110 is ultimately burned by pilot 32. Gas entering branch line G0 may ultimately be burned by main burner 31 or may be used to operate other system components connected to line 61 which branches from line 60.
Branch line 58 immediately downstream from the point where it branches is connected to a pressure regulator 62 which reduces the pressure in downstream line portion 63 to a pressure P1 which may be e.g. 10 psig. Line portion 63 is ~'Z~56~;
connected to a check valve 66 which is in turn connected to line portion 68 which terminates in gas jet 70 described in further detail hereinafter with reference to Fig. 3. Gas ~et 70 injects yas from line 68 into an enlarqed vertical 05 pipe 80 which is also connected at the lower end thereof to heating glycol circulation conduit 44. Gas entering pipe 80 from gas jet 70 aerates and t~-ansfers mechanical energy to glycol within pipe 80 causing it to flow upwardly and ultimately causing glycol in line 44 and the remainder of the circulating loop 34 to flow in the same direction producing circulation within the circulating loop 34 which varies with the amount of gas injected. Gas after leaving the gas jet bubbles out of the open end 82 of pipe 80 and is captured in cylindrical expansion riser portion 84. The expansion riser portion comprises a closed lower end 86 and a sealed upper end 88. A gas collection area 87 is provided between the sealed upper end 88 and the surface level 85 of the heating glycol 17 contained within the expansion riser.
A gas scrubber 90 which removes entrained liquids from gas as it leaves gas collection area 87 is sealingly attached to riser upper portion 88 in fluid communication with gas in collection area 87. A gas line 91 from scrubber 90 is connected through a check valve 93 to a conventional drip pot 92. The gas thereafter is discharged through drip pot outlet line 94 to burner pilot 32 passing first through a pressure regulator 96 which reduces the pressure in line portion 97 immediately downstream thereof to a pressure P2 compatible with pilot burner operation e.g. 3 psig.
needle valve 98 or the like may be positioned in line 12~'~5C~5 portion 97 to manually shut off gas flow to the pilot burner 32.
Branch line 110 has pressure regulator 111 immediately downstream from the branch which reduces tlle pressure in 05 downstream line portion 112 to a pressure P3 which is somewhat hiyher than Pl. For example, if Pl is 10 psig, P3 may be 15 psig. Line 112 is connected to a reverse throttling thermostat assembly 28 sensitive to the temperature of the li~uids 15 in separator 12. The reverse throttling thermostat assembly may comprise a reverse throttling thermostat 115 and associated control valve 117 which may be of a pneumatic type well known in the art such as sold by KIMRAY INC. of Oklahoma City, Oklahoma, e.g.
model number T12DA. The reverse throttling thermostat assembly 115, 117 has the characteristic, within a selected temperature range, of progressively opening the control valve 117 portion thereof when the sensed temperature rises and of progressively closing the control valve 117 as the sensed temperature falls the valve remaining in a fully open or fully closed state when the sensed temperature is outside the selected range. The selected temperature range may be e.g. +2 of the optimum separator operating temperature.
By-pass line portion 113 from the thermostat assembly is connected through check valve 11~ to drip pot 92. Thus gas passiny through branch line 110 and gas passing through gas injection line ~3 is ultimately collected in drip pot 92 prior to beiny burned in pilot burner 32. It may be seen that the gas flow rates through lines 58 and 110 are interdependent and ultimately determined by the pilot burner gas consump~ion rate, usually a constant value, and the . .
, 1294~65 separator temperature. Due to the fact that pressure P3 is set higher than Pl, any opening of the thermostat assembly results in an increased flow of gas through line 110 and a corresponding decrease in the flow of gas in line 58, and 05 vice versa.
It may be seen that such an arrangement enables maximum yas flow through the gas jet to be provided to increase the circulation rate of heating glycol and thus to provide a high rate of heat transfer to the separator bath, when the separator temperature falls significantly below its optimum operating temperature. It may also be seen that as the separator temperature rises, the circulation rate of the heating glycol will gradually be decreased by opening of the thermostat assembly with a resulting reduction in injection gas flow through line 58.
The second branch 60 of the line leaving drip pot 56 is connected to a pressure regulator 140 which reduces the gas pressure in the line to a pressure P4 e.g. 12-18 psig which is compatible with main burner operation. Line portion 142 immediately downstream of pressure regulator 140 is connected to reboiler thermostat assembly 144 which controls flow of qas through line 146 to main burner 31 in response to the temperature of heating glycol within the rèboiler in a conventional manner well known in the art. A manual control valve 148 may be provided in the gas line immédiately upstream of the burner.
A more detailed illustration of the gas jet 70 is provided by Fig. 3 wherein it is shown that vertical pipe 80 terminates in a sealed lower end 170 which is tapped to receive a conventional threaded elbow 172 in sealed ,~ .~ . ; .. 'i, 12~4565 relationship therewith. Elbow 17~ is collnected to gas line portioll Gn at the lower end thereof and in turn has a small diameter, e.g. 1/4 inch, pipe 174 threadingly attached to an upper portion thereof. The pipe 174 may be on the order of 05 four to six inches in length, terminating at an open end 178 out of whicll gas 179 is injected into the heating glycol in surrounding pipe 80. Glycol flows into pipe 80 through line 44 which enters a lower sidewall portion of pipe 80 immediately below the reboiler 30.
In operation, gas is continuously supplied to the burner pilot at a flow rate equal to the pilot's reyuired gas consumption rate. The pilot is in continuous fluid communication with supply line 51 through drip pot 56, lines 57, and gas jet line 58 etc. and/or by-pass line 110 etc.
Gas from the gas jet, through a jetting effect within pipe 80, transfers energy to the glycol in the area immediately surrounding the jet urging the glycol in the pipe 80 in an upward direction ~hich thereby causes glycol to circulate through the entire circulating loop 34 at a rate dependent on the gas flow rate through jet 70. Gas from the jet at a pressure equal to pressure Pl in line 63, less the hydrostatic fluid head, is collected in gas collection area 87. This gas and/or gas from by-pass line 110 etc. is continuously supplied to drip pot 92 and thence to the burner pilot where it is continuously burned. Thus all of the gas used to circu]ate the heating glycol within loop 34 and all by-pass gas is ultimately burned by the burner pilot 32. Thermostat assembly 28 controls the heating glycol circulation rate to maintain the separator contents at the optimum operating temperature by controlling the gas flow .
. ~ :
~25~45~;S
rate in by-pass line 110 whic}l, in turn, controls the flow rate through gas jet line 58 etc. The main burner 31 which is supplied through line 60 is operated intermittently depending upon the temperature of heating glycol within the 05 reboiler. The reboiler thermostat 144 is set to operate within an optimum temperature range, thus when the temperature in the reboiler falls below the optimum range, thermostat assembly 144 causes gas to flow through line 146 to the burner. When the temperature in the reboiler rises above the optimum range, thermostat assembly 144 terminates the flow of gas through line 146 to the burner.
Thus it will be seen that variable amounts of circulation energy may be provided to glycol in circulation loop 34 as required, independently of the operation of the main burner.
In a slightly different embodiment of the invention illustrated in Fig. 2, burner supply ]ine 142 is connected to drip pot discharge line 94 rather than line 60. Thus the gas to main burner 31 as ~ell as the burner pilot 32 comes from drip pot 92 after passing through gas jet branch 58 and/or by-pass branch 110. The remainder of the system may be identical to the system illustrated in Fig. 1. In this arrangement, when burner supply line 146 is opened by thermostat 144, a relatively large amount of gas is demanded which passes through line 58 etc. and gas jet 70 and/or by-pass line 110 etc. as determined by thermostat assembly 28. As a result a substantially increased amount of gas may be jetted through gas jet 70 with a corresponding increase in the maximum circulation rate of the system whenever the main burner 31 is fired. During periods when the main 1~3~5~i5 burner is not firing, gas may still be continuously jetted thrQugh the yas jet 70 in accordance Witil the demands of the pilot burner 32. Thus in either embodiment a continuous circulation of lleatiny glycol between the separator and 05 reboiler may be provided except in situations when this circulation flow is temporarily terminated by alternate gas flow through by-pass line 110, etc. due to elevation of the separator temperature above the optimum temperature.
Thus flow energy of natural gas from the well head is always available to circulate heating ylycol and all of the gas used to produce this circulation is ultimately consumed by the reboiler burner means. ~s a result a rapid response separator heating system is provide which uses no more natural gas than a more slowly responding thermosyphon type system.
It is contemplated that thc inventivc c~ncepts herein described may be variously otherwise embodied and it is intended that thl appended claims be construed to include alternative embodiments of the invention except insofar as limited by the prior art.
~ T ~-
Examples of gas separating and dehydrating units are disclosed in United States Patent Nos. 3,094,574; 3,288,448;
4,342,572; 4,421,062 and copending Patent Application Serial No.
487,591 for FLUID PUMPING SYSTEM of Charles R. Gerlach and Rodney T. Heath. In general, such units comprise a separator means for receiving the gas-oil-water mixture from the well head and separating the oil and water liquids from "wet" (water vapor laden) gas; and a water absorber means, which employs a liquid dehydrating agent such as glycol, for removing the water JJ~
1~94565 vapor from the gas subsequellt to its passage through the separator and producing "dry" gas suitable for commercial usage.
Such well gas dehydration units may comprise two 05 separate glycol circulation systems. One glycol circulation system, sometimes referred to as the glycol heating system, circulates glycol throuyh a closed loop between a heating means such as a reboiler and the separator means in order to maintain the temperature in the separator at an optimum value for separating oil and water mixture from the well effluent. Circulation oL glycol in such a heating glycol circulation system is sometimcs provided by a thermosyphon flow produced by the temperature difference between the separator and the reboiler. ~nother glycol circulation system, sometimes referred to as the process glycol circulation system, is generally caused to circulate by a glycol pump. The process g~ycol is continuously supplied to the absorber means in a "dry" low water vapor pressure condition and is removed from the absorber means in a "wet"
high water vapor pressure condition. The wet glycol is continuously removed from the absorber means and circulated through a treater means which may include the reboiler means (which is also used to heat the heating glycol) and a sLill column, etc. for removing the absorbed water from the wet process glycol to provide a new supply of dry process glycol. The glycol reboiler means usually comprises a gas burner for heating the glycol therein. Since the separating/dehydrating units are continuously operated at well sites without continuous monitoring by operating personnel, reliable continuous operation of the glycol ...
:' ' .. i. ' ' S~i5 circulation systems is of critical importance. Because of the often remote location of wells, it is highly desirable to use energy sources readily available at a well site for operation of these circulation systems. Since the glycol heating system uses substantial amounts of energy it is of uptnost economic importance to operate this 5 system with maximum efficiency and minimum energy loss.
Although the use of a thermosyphon, such as described in Heath, U.S.
Patent No. 4,342,572, to product circulation in a heating glycol system is extremely energy efficient, a drawback of thermosyphon circulation is that it is relatively slow and thus limits the speed at which heat can be transferred to the separator by the 10 heating glycol system.
Another manner of producing circulation in a heating glycol system is through use of a gas jet pump as described in U.S. Patent No. 4,421,062 of Padilla Sr. In this arrangement, well gas, after passing through a series of drip pots and regulators which reduces the gas pressu~e to about 25 psi, is injected into a heating 15 glycol flow line which forms part of a closed loop system between a high pressure separator and a reboiler. The gas is injected through a nozzle structure directed toward the reboiler and induces a venturi effect on the glycol in the surrounding portion of the glycol flow line to produce upward flow thereof through a lift pipe portion of the flow line into the reboiler which consequently produces circulation 20 of heating glycol frorn an opposite end of the reboiler into the separator. A
relatively high circulation rate flow of JJ: 3 129~565 ileating glycol may be provided between the separator and the reboiler so long as gas is discharged through the gas nozzle structure. Gas flow to the gas nozzle structure is controlled by a thermostat in the separator which permits a 05 gas flow through the gas nozzle structure whensver the separator temperature falls below a predetermined value and which shuts off the gas flow to terminate the circulation of heating glycol whenever the separator temperature exceeds another predetermined value. Gas discharged from the nozzle structure into the glycol flow is subsequently collected in a scrubber housing above the reboiler tank and is thereafter discharged through a gas outlct line having a relief valve set at approximately 23 psi. The gas outlet line from the scrubber passes through another series of check valves and is connected to the burner and burner pilot. The burner is turned on and off in response to a control signal from a thermostat in the reboiler. Thus, some of the gas discharged through the gas nozzle structure to produce circulation of heating glycol between the separator and reboiler is available for use by the burner and burner pilot. A problem with this system is that a great deal of the gas discharged through the gas jet may of necessity be vented to the atmospllere during periods when the gas jet is operating without the burner firing. Thus, this system may waste considerable amounts of gas.
It would be generally desirable to provide a heating glycol circulation system for circulating heating glycol between a reboiler and high pressure separator which provides the extremely high energy efficiency of a thermosyphon heating system while providing the relatively . . .
l'Z945f~5 high speed circuLatioll capability of a gas injection type circulatiotl system without waste of valuable sale gas.
It would also bc desirable to provide a heating glycol system which continuously circulates heating glycol to a 05 separator at a rate which is dependent upon the current heat requirements of the separator.
Summary of the Invention The present invention provides a heating system for a high pressure separator which utilizes circulation of heating glycol between tlle separator and a heating means such as a reboiler for heating the separator. The heating glycol is heated by a burner and associated fire tube positioned in the heating means and fueled by natural gas from the well. In one embodiment, which is presently the best mode contemplated, a controllably variable portion of the natural gas which is ultimately used by a burner pilot is initially injected into the heating glycol circulation loop to produce glycol circulation. The maximum amount of gas which may be injected is dependent on the pilot burner gas collsumption rate, thus nonb of this injected gas must be vented to the atmosphere. A thermostatically controlled gas jet by pass line which allows a selectably variable portion of the burner pilot gas to by-pass the gas jet is opened and closed dependent upon the temperature in the high pressure separator. After gas is jetted into the glycol, it is recovered in a sealed gas collection area above the glycol in the heating means. Gas from other heating system operating components may also bc collected in the gas collection area. All of this collected gas is in fluid lZ94565 conununicatioll with and is ultimately burned by th burner pilot. Pilot gas which by-passes the gas jet communicates with the recovered injection gas either in the collection area or, preferably, downstream of the collection area near 05 the pilot burner inlet. The injection of gas into the heating glycol causes a jetting effect which transfers energy to the heating glycol and provides a circulation rate therein which is dependent upon the amount of gas injected.
The maximum circulation rate provided by this controlled gas injection is significantly yreater than that provided by a thermosyphon type circulation system. Thus, the capability of the heating glycol system of the present invention to deliver heat to the separator is considerably better than that of a thermosyphon type system, yet the energy consumption requirements of the system of the present invention are no greater than that of a thermosyphon typc system because all gas used to increase the heating glycol flow rate is later burned to heat the heating glycol.
Control gas for operating various separator controls may be provided from the same gas supply system used for gas injection into the heating glycol.
Thus, a heating glycol system having a controllable circulation rate with a relatively high maximum circulation rate i~ provided which uses energy sources provided at the well site very efficiently.
In a slightly different embodiment of the invention, a controlled amount up to a maximum amount of all of the burner gas as well as all the burner pilot gas may be initially injected into the heating glycol circulation loop.
Thus a considerably grcater amount of gas may be injected 5~5 throuyh the gas jet than in the previously discussed embodiment with a correspondingly greater maximum glycol circulation flow rate.
Thus, the invention may comprise a well effluent 05 separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature ranye for receiving well effluent and for separating said well effluent into a liquid component and a relatively liquid free gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator lS means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner mcans operatively associated with said heating means for heating said heat exchange liquid therein;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for enabling circulation of said heat exchange liquid between said heating means and said heat cxchange conduit means in said separator means;
g) operating gas supply line means for supplying well gas for heatiny and for operating various separator control systems;
5~i5 h) gas jet means in fluid communication with said operating gas supply line means for injecting gas into said circulation conduit means for producing circulation of said heat exchange liquid in said 05 circulation conduit means;
i) sealed gas recapture means for recapturiny substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in continuous fluid communication with said burner pilot means whereby yas collected by said gas recapture means is subsequently burned by said burner pilot means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner lS pilot means to by-pass said gas jet means;
k) whereby the circulation rate of said heat exchange liquid is variably controllable through control of the amount of gas injected into said circulation conduit means.
The invention may also comprise a well effluent separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a wet gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said 5~5 heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum 05 operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said llcat exchange liquid in said heating means;
e) gas operated burner pilot means l~r igniting said burner means;
f) circulation conduit means for providing circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply means for injecting gas into said circulation conduit means for circulating said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said yas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in fluid communication with said burner pilot means and with said burner means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner ., ~ ~
1~9~565 pilot means and said burner means to by-pass said gas jet means;
k) burner control valve means operatively associated with said main burner means for selectively controlling 05 the gas flow to said main burner means r l) heating means thermostat means operatively associated with said burner control valve means for controlling the gas flow to said burner means in response to the temperature in a selected portion of said heatiny means whereby said burner means is selectively operated to maintain the temperature in said selected portion of said heating means within said optimum operatiny temperature range;
m) whereby pressure energy from all gas in~ected into said circulation conduit means is used to increase the circulation rate of said heat exchange liquid in said circulation conduit means and whereby gas collected in said sealed gas recapture means is subsequently burned by said burner pilot means and said burner means and whereby the circulation rate of said heat exchange liquid is variably controlled through the amount of gas injected into said circulation conduit means, Brief Description of the Drawing Fig, 1 is a schematic drawing showing basic operating components of a circulating glycol heating system for a high pressure separator of the type used at a gas well head.
Fig. 2 is a schematic drawing showing a modification of the burner gas supply shown in Fig. 1.
`i: '~ ` ! ` .
12~45~5 Fig. 3 is a detailed cross sectional elevation view of a gas jet and a portion of the heating glyco] circulQtion conduit of Fig. 1.
05 Detailed Description of the Invention The well effluent separator system 10 of the present invention is adapted for use at a gas well head for processing well effluent to obtain dry sale gas therefrom.
The invention in general includes a high pressure separator 12 adapted to receive well gas 14 to separate and remove certain entrained liquids therefrom; a heating means such as a reboiler 30 which heats a supply of heating fluid such as heating glycol 17 in a riser portion 84 thereof; circulating loop 34 which circulates heating glycol between the reboiler 30 and separator 12 to provide heat to the separator; a drying assembly such as absorber 18 for drying well gas received from the separator 12 to produce dry sale gas 20;
and a burner assembly including a burner 31 and a burner pilot 32, used in combination with a fire tube 33 to heat glycol in the heating means. The burner means is fueled by gas wl-ich is supplied from the sale gas line leaving the absorber 18. At least a portion of the gas which is ultimately burned by the burner assembly is first injected by a gas jet 70 into the heating glycol circulation loop 34 z5 thereby transferring mechanical energy to the heating glycol to cause it to circulate. All of the gas injected into the heating glycol is subsequently recaptured and burned in the burner assembly. In one embodiment, Fig. 1, the recaptured gas is burned only by the burner pilot 32. In another embodiment, Fig. 2, the rccaptured gas is burned by both the ~: `
lZ945G~;
main burner 31 and the burner pilot 32. ~ reverse acting thermostat assembly 28 in tlle separator 12 is associated with a gas jet by-pass line 110. All of the gas supplied to the burner pilot, in the the embodiment shown in Fig. 1, 05 flows through either the gas jet line or the gas jet by-pass line. In the second embodiment of Fig. 2, all of the burner assembly gas flows through these two lines. The gas flow through the by-pass line increases, and the gas flow through the gas jet correspondingly decreases, with an increase in the temperature of the separator. The circulation rate of heating glycol varies with the injection gas flow rate.
Since the heating glycol is maintained at a nearly constant temperature, the amount of heat transferred to the separator by the heating glycol i5 dependent on the heating glycol circulation rate. The temperature in the separator is thus maintained near an optimum value through thermostatic control of gas flow through by-pass line 110 to control the injection gas flow rate which in turn controls the heating glycol circulation rate. Having thus described the invention in general, certain features of the invention will now be described in further detail.
High pressure separator 12 includes a well effluent inlet 13 whereat well gas 14 is received from the well head.
The gas passes through a demister ~not shown) which causes oils and other liquids to be separated from the well effluent. These liquids 15 from the well gas are collected in the lower portion of the separator and are heated by heating conduit 42 to maintain the temperature of the separator liquid near a preset optimum value. The separator liyuids 15 are periodically removed from the separator by 1~9~5~5 convent;onal dump valve arran~ements (not shown) as described in U.S. P~ent No.
4,342,572. Gas is discharged from the separator through outlet line ]6 to various conventional drying assemblies, such as described in U.S. Patent No. 4,342,572 and elsewhere, for further removing moist~lre from the gas. The drying assemhlies are collectively represented herein as absorber unit 18. Gas containing substantial amounts of water vapor is received at an absorber inlet 19 and dry sale gas 20 is subsequently discharged from the absorber outlet 21 to sale gas line 50. The absorber unit 18 utilizes process glycol to dry the well gas passing therethrough.
Dry process glycol 22 from the reboiler 30 is received at the absorber glycol inlet 23 and wet process glycol 24, which carries away moisture from the well gas, is discharged to the reboiler 30 from the absorber at process glycol outlet 25. Thewet process glycol from the absorber is partially dried in a still column 29 portion of the reboiler 30 and is thereafter stored in a process glycol tank 27 portion of the reboiler 30 where it is maintained at an elevated temperature by means of burner31 and associated fire tube 33. l he reboiler process glycol tank 27 and still column 29 form part of a c]osed loop glycol drying system (shown only partially herein)which is operated at atmospheric pressure. Such a closed loop glycol drying system is described in detail in U.S. Patent 4,342,572 of Rodney Heath entitled THERMAL CIRCULATION GAS TREATER.
Some of the sale gas 20 which is normally discharged to gas pipelines, etc. for subsequent sale, may be directed, as JJ: 13 ~r lZ~3~56S
by control gas supply line 51, back to certain system operating components for subsequent use at the well head site as described further hereinaLter.
~ heating glycol means which may be reboiler 30 is 05 heated by a burner assembly including a main gas burner 31 and associated burner pilot 32. The ~ain burner and burner pilot are assembled in a conventional fire tube 33. The fire tube 33 extends into the reboiler tank 27 contacting a supply of process glycol contained tilerein which in turn transfers heat to heating glycol 17 contained in a closed loop glycol heating system which includes a heating glycol storage area provided by a sealed expansion riser 84 portion of the reboiler 30. Heating glycol 17 in expansion riser 84 is sealed off from process glycol in reboiler tank portion 27 as described in further detail below. The heating glycol contained by the expansion riser 84 circulates through circulation loop 34 which passes through separator 12 and then returns to the expansion riser. Circulation loop 34 includes a reboiler conduit coil portion 36 which passes through a portion of the reboiler tank 27. The reboiler coil 36 terminates in the riser 84 at an open end 37 into which glycol 17 from the riser a4 flows to begin circulation through the heating glycol circulation loop 34. Ileating glycol in coil 36 is heated as it flows through coil 36 by the process glycol in tank 27. The reboiler coil 36 is connected to an upper circulation flow line 38 extending between the reboiler and separator 12. Flow line 38 is connected to separator heating conduit 42. Separator heating conduit 42 is connected to circulation return flow lZ~4565 line 44 whicll provides the return flow of heating glycol to the expansion riser 84 to complete circulation loop 34.
As mentioned above, a gas supply line 51 in communication witll the sale gas line from the absorber 18 05 provides gas used to operate certain system components. Gas entering line 51 is at a relatively high pressure, e.g. 500 psig, which varies irom well to well. Line 51 may comprise a control valve 52 therein enabling the supply line to be isolated from the sale gas line 50. A pressure regulator 54 is provided in line 51 which reduces the pressure in the downstream line portion 55 to a pressure ~0 which may be e.g. 75 psig. Line portion 55 communicates with a conventional drip pot 56 having a conventional relief valve 53 and drain line 59. Gas for burner and certain other system operations discharges from the drip pot 56 through line 57. Line 57 branches into three branch gas lines 58, 60 and 110. Branch line 58 leads to gas jet 70 with the gas passing therethrough being used to circulate heating glycol 17 and ~eing ultimately burned by burner pilot 32. Line 110 is a gas jet by-pass line which when open reduces the gas flow through line 58 by an amount equal to the flow through line 110. Gas flowing through line 110 is ultimately burned by pilot 32. Gas entering branch line G0 may ultimately be burned by main burner 31 or may be used to operate other system components connected to line 61 which branches from line 60.
Branch line 58 immediately downstream from the point where it branches is connected to a pressure regulator 62 which reduces the pressure in downstream line portion 63 to a pressure P1 which may be e.g. 10 psig. Line portion 63 is ~'Z~56~;
connected to a check valve 66 which is in turn connected to line portion 68 which terminates in gas jet 70 described in further detail hereinafter with reference to Fig. 3. Gas ~et 70 injects yas from line 68 into an enlarqed vertical 05 pipe 80 which is also connected at the lower end thereof to heating glycol circulation conduit 44. Gas entering pipe 80 from gas jet 70 aerates and t~-ansfers mechanical energy to glycol within pipe 80 causing it to flow upwardly and ultimately causing glycol in line 44 and the remainder of the circulating loop 34 to flow in the same direction producing circulation within the circulating loop 34 which varies with the amount of gas injected. Gas after leaving the gas jet bubbles out of the open end 82 of pipe 80 and is captured in cylindrical expansion riser portion 84. The expansion riser portion comprises a closed lower end 86 and a sealed upper end 88. A gas collection area 87 is provided between the sealed upper end 88 and the surface level 85 of the heating glycol 17 contained within the expansion riser.
A gas scrubber 90 which removes entrained liquids from gas as it leaves gas collection area 87 is sealingly attached to riser upper portion 88 in fluid communication with gas in collection area 87. A gas line 91 from scrubber 90 is connected through a check valve 93 to a conventional drip pot 92. The gas thereafter is discharged through drip pot outlet line 94 to burner pilot 32 passing first through a pressure regulator 96 which reduces the pressure in line portion 97 immediately downstream thereof to a pressure P2 compatible with pilot burner operation e.g. 3 psig.
needle valve 98 or the like may be positioned in line 12~'~5C~5 portion 97 to manually shut off gas flow to the pilot burner 32.
Branch line 110 has pressure regulator 111 immediately downstream from the branch which reduces tlle pressure in 05 downstream line portion 112 to a pressure P3 which is somewhat hiyher than Pl. For example, if Pl is 10 psig, P3 may be 15 psig. Line 112 is connected to a reverse throttling thermostat assembly 28 sensitive to the temperature of the li~uids 15 in separator 12. The reverse throttling thermostat assembly may comprise a reverse throttling thermostat 115 and associated control valve 117 which may be of a pneumatic type well known in the art such as sold by KIMRAY INC. of Oklahoma City, Oklahoma, e.g.
model number T12DA. The reverse throttling thermostat assembly 115, 117 has the characteristic, within a selected temperature range, of progressively opening the control valve 117 portion thereof when the sensed temperature rises and of progressively closing the control valve 117 as the sensed temperature falls the valve remaining in a fully open or fully closed state when the sensed temperature is outside the selected range. The selected temperature range may be e.g. +2 of the optimum separator operating temperature.
By-pass line portion 113 from the thermostat assembly is connected through check valve 11~ to drip pot 92. Thus gas passiny through branch line 110 and gas passing through gas injection line ~3 is ultimately collected in drip pot 92 prior to beiny burned in pilot burner 32. It may be seen that the gas flow rates through lines 58 and 110 are interdependent and ultimately determined by the pilot burner gas consump~ion rate, usually a constant value, and the . .
, 1294~65 separator temperature. Due to the fact that pressure P3 is set higher than Pl, any opening of the thermostat assembly results in an increased flow of gas through line 110 and a corresponding decrease in the flow of gas in line 58, and 05 vice versa.
It may be seen that such an arrangement enables maximum yas flow through the gas jet to be provided to increase the circulation rate of heating glycol and thus to provide a high rate of heat transfer to the separator bath, when the separator temperature falls significantly below its optimum operating temperature. It may also be seen that as the separator temperature rises, the circulation rate of the heating glycol will gradually be decreased by opening of the thermostat assembly with a resulting reduction in injection gas flow through line 58.
The second branch 60 of the line leaving drip pot 56 is connected to a pressure regulator 140 which reduces the gas pressure in the line to a pressure P4 e.g. 12-18 psig which is compatible with main burner operation. Line portion 142 immediately downstream of pressure regulator 140 is connected to reboiler thermostat assembly 144 which controls flow of qas through line 146 to main burner 31 in response to the temperature of heating glycol within the rèboiler in a conventional manner well known in the art. A manual control valve 148 may be provided in the gas line immédiately upstream of the burner.
A more detailed illustration of the gas jet 70 is provided by Fig. 3 wherein it is shown that vertical pipe 80 terminates in a sealed lower end 170 which is tapped to receive a conventional threaded elbow 172 in sealed ,~ .~ . ; .. 'i, 12~4565 relationship therewith. Elbow 17~ is collnected to gas line portioll Gn at the lower end thereof and in turn has a small diameter, e.g. 1/4 inch, pipe 174 threadingly attached to an upper portion thereof. The pipe 174 may be on the order of 05 four to six inches in length, terminating at an open end 178 out of whicll gas 179 is injected into the heating glycol in surrounding pipe 80. Glycol flows into pipe 80 through line 44 which enters a lower sidewall portion of pipe 80 immediately below the reboiler 30.
In operation, gas is continuously supplied to the burner pilot at a flow rate equal to the pilot's reyuired gas consumption rate. The pilot is in continuous fluid communication with supply line 51 through drip pot 56, lines 57, and gas jet line 58 etc. and/or by-pass line 110 etc.
Gas from the gas jet, through a jetting effect within pipe 80, transfers energy to the glycol in the area immediately surrounding the jet urging the glycol in the pipe 80 in an upward direction ~hich thereby causes glycol to circulate through the entire circulating loop 34 at a rate dependent on the gas flow rate through jet 70. Gas from the jet at a pressure equal to pressure Pl in line 63, less the hydrostatic fluid head, is collected in gas collection area 87. This gas and/or gas from by-pass line 110 etc. is continuously supplied to drip pot 92 and thence to the burner pilot where it is continuously burned. Thus all of the gas used to circu]ate the heating glycol within loop 34 and all by-pass gas is ultimately burned by the burner pilot 32. Thermostat assembly 28 controls the heating glycol circulation rate to maintain the separator contents at the optimum operating temperature by controlling the gas flow .
. ~ :
~25~45~;S
rate in by-pass line 110 whic}l, in turn, controls the flow rate through gas jet line 58 etc. The main burner 31 which is supplied through line 60 is operated intermittently depending upon the temperature of heating glycol within the 05 reboiler. The reboiler thermostat 144 is set to operate within an optimum temperature range, thus when the temperature in the reboiler falls below the optimum range, thermostat assembly 144 causes gas to flow through line 146 to the burner. When the temperature in the reboiler rises above the optimum range, thermostat assembly 144 terminates the flow of gas through line 146 to the burner.
Thus it will be seen that variable amounts of circulation energy may be provided to glycol in circulation loop 34 as required, independently of the operation of the main burner.
In a slightly different embodiment of the invention illustrated in Fig. 2, burner supply ]ine 142 is connected to drip pot discharge line 94 rather than line 60. Thus the gas to main burner 31 as ~ell as the burner pilot 32 comes from drip pot 92 after passing through gas jet branch 58 and/or by-pass branch 110. The remainder of the system may be identical to the system illustrated in Fig. 1. In this arrangement, when burner supply line 146 is opened by thermostat 144, a relatively large amount of gas is demanded which passes through line 58 etc. and gas jet 70 and/or by-pass line 110 etc. as determined by thermostat assembly 28. As a result a substantially increased amount of gas may be jetted through gas jet 70 with a corresponding increase in the maximum circulation rate of the system whenever the main burner 31 is fired. During periods when the main 1~3~5~i5 burner is not firing, gas may still be continuously jetted thrQugh the yas jet 70 in accordance Witil the demands of the pilot burner 32. Thus in either embodiment a continuous circulation of lleatiny glycol between the separator and 05 reboiler may be provided except in situations when this circulation flow is temporarily terminated by alternate gas flow through by-pass line 110, etc. due to elevation of the separator temperature above the optimum temperature.
Thus flow energy of natural gas from the well head is always available to circulate heating ylycol and all of the gas used to produce this circulation is ultimately consumed by the reboiler burner means. ~s a result a rapid response separator heating system is provide which uses no more natural gas than a more slowly responding thermosyphon type system.
It is contemplated that thc inventivc c~ncepts herein described may be variously otherwise embodied and it is intended that thl appended claims be construed to include alternative embodiments of the invention except insofar as limited by the prior art.
~ T ~-
Claims (16)
1. A well effluent separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a relatively liquid free gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said heat exchange liquid therein;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for enabling circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply line means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply line means for injecting gas into said circulation conduit means for producing circulation of said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in continuous fluid communication with said burner pilot means whereby gas collected by said gas recapture means is subsequently burned by said burner pilot means;
j) gas jet by-pass means in fluid communication with said operating gas supply line means and said burner pilot means for enabling a variably controllable amount of the gas supplied to said burner pilot means to by-pass said gas jet means;
k) whereby the circulation rate of said heat exchange liquid is variably controllable through control of the amount of gas injected into said circulation conduit means.
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a relatively liquid free gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said heat exchange liquid therein;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for enabling circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply line means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply line means for injecting gas into said circulation conduit means for producing circulation of said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in continuous fluid communication with said burner pilot means whereby gas collected by said gas recapture means is subsequently burned by said burner pilot means;
j) gas jet by-pass means in fluid communication with said operating gas supply line means and said burner pilot means for enabling a variably controllable amount of the gas supplied to said burner pilot means to by-pass said gas jet means;
k) whereby the circulation rate of said heat exchange liquid is variably controllable through control of the amount of gas injected into said circulation conduit means.
2. The invention of claim 1 wherein the amount of gas injected by said gas jet means is dependent upon said burner pilot means gas consumption requirements and the temperature in said high pressure separator means.
3. The invention of claim 2, said gas jet by-pass means comprising:
separator thermostat means operatively associated with said separator means for sensing the temperature therein and for providing a control signal responsive thereto for selectively varying the amount of gas passing through said gas jet by-pass means.
separator thermostat means operatively associated with said separator means for sensing the temperature therein and for providing a control signal responsive thereto for selectively varying the amount of gas passing through said gas jet by-pass means.
4. The invention of claim 3 said gas jet by-pass means comprising control valve means operatively associated with said separator thermostat means and, within a preset separator temperature range including said optimum separator operating temperature, being progressively closeable in response to descending separator means temperature and progressively openable in response to rising separator means temperature.
5. The invention of claim 1, 2 or 3 wherein said burner pilot consumes gas at a substantially constant preset rate and wherein any gas received by said burner pilot pass through one of said gas jet means and said gas jet by-pass means, whereby an increase in gas flow through said gas jet by-pass means causes a corresponding decrease in gas flow through said gas jet means and a decrease in gas flow through said gas jet by-pass means causes a corresponding increase in gas flow through said gas jet means.
6. The invention of claim 1 wherein:
said sealed gas recapture means comprises a gas chamber in fluid communication with said hot heat exchange liquid in said heating means.
said sealed gas recapture means comprises a gas chamber in fluid communication with said hot heat exchange liquid in said heating means.
7. The invention of claim 6 wherein said sealed gas recapture means further comprises:
a gas dryer in fluid communication with said gas chamber; and a drip pot in fluid communication with said gas chamber.
a gas dryer in fluid communication with said gas chamber; and a drip pot in fluid communication with said gas chamber.
8. A well effluent separator system for use at a well head for processing well effluent to obtain relatively liquid free gas comprising:
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a wet gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said heat exchange liquid in said heating means;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for providing circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply means for injecting gas into said circulation conduit means for circulating said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in fluid communication with said burner pilot means and with said burner means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner pilot means and said burner means to by-pass said gas jet means;
k) burner control valve means operatively associated with said main burner means for selectively controlling the gas flow to said main burner means;
l) heating means thermostat means operatively associated with said burner control valve means for controlling the gas flow to said burner means in response to the temperature in a selected portion of said heating means whereby said burner means is selectively operated to maintain the temperature in said selected portion of said heating means within said optimum operating temperature range;
m) whereby pressure energy from all gas injected into said circulation conduit means is used to increase the circulation rate of said heat exchange liquid in said circulation conduit means and whereby gas collected in said sealed gas recapture means is subsequently burned by said burner pilot means and said burner means and whereby the circulation rate of said heat exchange liquid is variably controlled through the amount of gas injected into said circulation conduit means.
a) high pressure separator means having an optimum operating temperature range for receiving well effluent and for separating said well effluent into a liquid component and a wet gas component;
b) heat exchange conduit means in said high pressure separator means for receiving a flow of heat exchange liquid therethrough for transferring heat from said heat exchange liquid to the contents of said separator means;
c) heating means for providing a supply of hot, heat exchange liquid, said heating means having an optimum operating temperature range;
d) gas operated burner means operatively associated with said heating means for heating said heat exchange liquid in said heating means;
e) gas operated burner pilot means for igniting said burner means;
f) circulation conduit means for providing circulation of said heat exchange liquid between said heating means and said heat exchange conduit means in said separator means;
g) operating gas supply means for supplying well gas for heating and for operating various separator control systems;
h) gas jet means in fluid communication with said operating gas supply means for injecting gas into said circulation conduit means for circulating said heat exchange liquid in said circulation conduit means;
i) sealed gas recapture means for recapturing substantially all of said gas injected into said circulation conduit means by said gas jet means, said sealed gas recapture means being in fluid communication with said burner pilot means and with said burner means;
j) gas jet by-pass means for enabling a variably controllable amount of the gas supplied to said burner pilot means and said burner means to by-pass said gas jet means;
k) burner control valve means operatively associated with said main burner means for selectively controlling the gas flow to said main burner means;
l) heating means thermostat means operatively associated with said burner control valve means for controlling the gas flow to said burner means in response to the temperature in a selected portion of said heating means whereby said burner means is selectively operated to maintain the temperature in said selected portion of said heating means within said optimum operating temperature range;
m) whereby pressure energy from all gas injected into said circulation conduit means is used to increase the circulation rate of said heat exchange liquid in said circulation conduit means and whereby gas collected in said sealed gas recapture means is subsequently burned by said burner pilot means and said burner means and whereby the circulation rate of said heat exchange liquid is variably controlled through the amount of gas injected into said circulation conduit means.
9. A method of heating a natural gas separator of the type used at a natural gas well head comprising:
a) heating a supply of heat exchange fluid in a heating unit having a gas operated burner and burner pilot;
b) providing a closed loop circulation line containing heat exchange fluid in heat exchanging relationship with the heating unit and in heat exchanging relationship with the separator;
c) injecting gas recovered from the well head through a jet nozzle into the heat exchange fluid in the closed loop circulation line so as to circulate the heat exchange fluid in the circulation line;
d) controlling the amount of gas injected into the heat exchange fluid by selectively controlling gas flow rate in a gas jet by-pass line in fluid communication with the gas jet inlet and with the burner pilot;
e) collecting the gas injected into the circulation line in a sealed collection area;
f) continuously using the gas collected in the collection area and gas from the gas jet by-pass line to fuel the burner pilot.
a) heating a supply of heat exchange fluid in a heating unit having a gas operated burner and burner pilot;
b) providing a closed loop circulation line containing heat exchange fluid in heat exchanging relationship with the heating unit and in heat exchanging relationship with the separator;
c) injecting gas recovered from the well head through a jet nozzle into the heat exchange fluid in the closed loop circulation line so as to circulate the heat exchange fluid in the circulation line;
d) controlling the amount of gas injected into the heat exchange fluid by selectively controlling gas flow rate in a gas jet by-pass line in fluid communication with the gas jet inlet and with the burner pilot;
e) collecting the gas injected into the circulation line in a sealed collection area;
f) continuously using the gas collected in the collection area and gas from the gas jet by-pass line to fuel the burner pilot.
10. The invention of claim 9 comprising the further steps of:
a) continuously monitoring the temperature of the separator contents;
b) controlling the gas flow through the gas jet by-pass line based on the separator contents temperature.
a) continuously monitoring the temperature of the separator contents;
b) controlling the gas flow through the gas jet by-pass line based on the separator contents temperature.
11. The invention of claim 10 wherein the step of controlling by-pass line gas flow based on separator contents temperature comprises, within a preselected separator temperature range, progressively opening a control valve in the by-pass line to increase gas flow therein during increasing separator temperature conditions and progressively closing said control valve to decrease gas flow in the by-pass line during decreasing separator temperature conditions so as to increase gas injection during decreasing separator temperature conditions and so as to decrease gas injection during increasing separator temperature conditions within said selected separator temperature range.
12. A method of heating a natural gas separator of the type used at a natural gas well head comprising:
a) heating a supply of heat exchange fluid in a heating unit having a gas burner and burner pilot;
b) providing a closed loop circulation line containing heat exchange fluid in heat exchanging relationship with the heating unit and in heat exchanging relationship with the separator;
c) injecting gas recovered from the well head through a jet nozzle into the heat exchange fluid in the closed loop circulation line so as to circulate the heat exchange fluid in the circulation line;
d) controlling the amount of gas injected into the heat exchange fluid by selectively controlling gas flow rate in a gas jet by-pass line in fluid communication with the gas jet inlet and with the burner;
e) collecting the gas injected into the circulation line in a sealed collection area;
f) continuously using the gas collected in the collection area and gas from the gas jet by-pass line to fuel the burner and burner pilot.
a) heating a supply of heat exchange fluid in a heating unit having a gas burner and burner pilot;
b) providing a closed loop circulation line containing heat exchange fluid in heat exchanging relationship with the heating unit and in heat exchanging relationship with the separator;
c) injecting gas recovered from the well head through a jet nozzle into the heat exchange fluid in the closed loop circulation line so as to circulate the heat exchange fluid in the circulation line;
d) controlling the amount of gas injected into the heat exchange fluid by selectively controlling gas flow rate in a gas jet by-pass line in fluid communication with the gas jet inlet and with the burner;
e) collecting the gas injected into the circulation line in a sealed collection area;
f) continuously using the gas collected in the collection area and gas from the gas jet by-pass line to fuel the burner and burner pilot.
13. The invention of claim 12 comprising the further steps of:
a) continuously monitoring the temperature of the separator contents;
b) controlling the gas flow through the gas jet by-pass line based on the separator temperature.
a) continuously monitoring the temperature of the separator contents;
b) controlling the gas flow through the gas jet by-pass line based on the separator temperature.
14. The invention of claim 13 wherein the step of controlling by-pass line gas flow based on separator contents temperature comprises, within a preselected separator temperature range, progressively opening a control valve in the by-pass line to increase gas flow therein during increasing separator temperature conditions and progressively closing said control valve to decrease gas flow in the by-pass line during decreasing separator temperature conditions so as to increase gas injection during decreasing separator temperature conditions and so as to decrease gas injection during increasing separator temperature conditions within said selected separator temperature range.
15. The invention of claim 14 comprising the further step of:
controlling the flow of gas to the gas burner and burner pilot based upon the temperature of fluid in the heating unit.
controlling the flow of gas to the gas burner and burner pilot based upon the temperature of fluid in the heating unit.
16. The invention of Claim 4 wherein said burner pilot consumes gas at a substantially constant preset rate and wherein any gas received by said burner pilot pass through one of said gas jet means and said gas jet by-pass means, whereby an increase in gas flow through said gas jet by-pass means causes a corresponding decrease in gas flow through said gas jet means and a decrease in gas flow through said gas jet by-pass means causes a corresponding increase in gas flow through said gas jet means.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/835,516 US4689053A (en) | 1986-03-03 | 1986-03-03 | Heating system with gas jet driven circulation flow for high pressure well head separator |
| US835,516 | 1986-03-03 | ||
| US88333986A | 1986-07-08 | 1986-07-08 | |
| US883,339 | 1986-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1294565C true CA1294565C (en) | 1992-01-21 |
Family
ID=27125796
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 530483 Expired CA1294565C (en) | 1986-03-03 | 1987-02-24 | Heating system with gas jet driven circulation flow for high pressure well head separator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1294565C (en) |
-
1987
- 1987-02-24 CA CA 530483 patent/CA1294565C/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |