U.S. patent application number 11/003571 was filed with the patent office on 2006-06-08 for gas burner control and ignition system for oilfield separators.
Invention is credited to Jeff Davis.
Application Number | 20060118644 11/003571 |
Document ID | / |
Family ID | 36573104 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060118644 |
Kind Code |
A1 |
Davis; Jeff |
June 8, 2006 |
Gas burner control and ignition system for oilfield separators
Abstract
The present invention provides methods and apparatuses for
controlling a heater for an oil and gas separator. According to the
present invention, a spark is provided for igniting a gas burner.
The spark is controlled such that the gas burner is ignited,
without unduly complex control or sensor requirements. In the
description below, generally an entire temperature-controller
separator is described to provide context for the discussion. The
invention also contemplates just the heating subsystem, e.g. to
mount with existing separators. The invention also contemplates
just the heating control subsystem, e.g., to retrofit existing
pilot ignition subsystems.
Inventors: |
Davis; Jeff; (La Plata,
MN) |
Correspondence
Address: |
V. Gerald Grafe, esp.
P.O. Box 2689
Corrales
NM
87048
US
|
Family ID: |
36573104 |
Appl. No.: |
11/003571 |
Filed: |
December 2, 2004 |
Current U.S.
Class: |
236/1A ;
236/15BD |
Current CPC
Class: |
F23N 5/022 20130101;
F23N 2227/02 20200101; F23N 5/242 20130101; F23N 2227/36 20200101;
F23D 2207/00 20130101 |
Class at
Publication: |
236/001.00A ;
236/015.0BD |
International
Class: |
F23D 1/00 20060101
F23D001/00 |
Claims
1. A gas burner control and ignition system for an oil and gas
separator, the separator capable of indicating when heat is
required, comprising: a) A gas valve having an inlet and an outlet,
where the inlet is adapted to accept gas from a gas supply and the
outlet is adapted to supply gas to a gas burner; b) a spark
generator, adapted to mount with the burner such that a spark from
the spark generator ignites gas in the gas burner; c) a burner
temperature sensor, adapted to mount with the gas burner and
generate a burner temperature signal representative of heat
generated by the gas burner; d) a valve control subsystem, enabling
gas flow through the gas valve when the separator indicates that
heat is required; e) a spark control subsystem, enabling the spark
generator when both (1) the separator indicates that heat is
desired, and (2) the burner temperature signal indicates that the
burner has not generated a determined amount of heat.
2. A gas burner control and ignition system for an oil and gas
separator, comprising: a) a gas valve having an inlet and an
outlet, where the inlet is adapted to accept gas from a gas supply
and the outlet is adapted to supply gas to a gas burner; b) a spark
generator, adapted to mount with the burner such that a spark from
the spark generator ignites gas in the gas burner; c) a burner
temperature sensor, adapted to mount with the gas burner and
generate a burner temperature signal representative of heat
generated by the gas burner; d) a separator temperature sensor,
adapted to mount with the separator and generate a signal
representative of the temperature of the contents of the separator;
e) a valve control subsystem, responsive to the separator
temperature sensor, enabling gas flow through the gas valve when
the temperature of the contents of the separator is below a
determined temperature; f) a spark control subsystem, enabling the
spark generator when both (1) the temperature of the contents of
the separator is below a determined temperature, and (2) the burner
temperature signal indicates that the burner has not generated a
determined amount of heat.
3. A temperature control system for an oil and gas separator,
comprising: a) a gas burner, adapted to mount with the separator
and impart heat thereto; b) a gas burner control and ignition
system according to claim 2.
4. An oil and gas separator, comprising: a) a separator vessel; b)
a temperature control system according to claim 3.
5. A gas burner control and ignition system for an oil and gas
separator, comprising: a) a gas valve having an inlet and an
outlet, where the inlet is adapted to accept gas from a gas supply
and the outlet is adapted to supply gas to a gas burner; b) a spark
generator, adapted to mount with the burner such that a spark from
the spark generator ignites gas in the gas burner; c) a burner
temperature sensor, adapted to mount with the gas burner and
generate a burner temperature signal representative of heat
generated by the gas burner; d) a separator temperature sensor,
adapted to mount with the separator and generate a signal
representative of the temperature of the contents of the separator;
e) a pressure sensor mounted with the gas valve generating a signal
indicative of the state of the gas valve; f) a valve control
subsystem, responsive to the separator temperature sensor, enabling
gas flow through the gas valve when the temperature of the contents
of the separator is below a determined temperature; g) a spark
control subsystem, enabling the spark generator when both (1) the
pressure sensor indicates that the gas valve is open, and (2) the
burner temperature signal indicates that the burner has not
generated a determined amount of heat.
6. A temperature control system for an oil and gas separator,
comprising: a) a gas burner, adapted to mount with the separator
and impart heat thereto; b) a gas burner control and ignition
system according to claim 5.
7. An oil and gas separator, comprising: a) a separator vessel; b)
a temperature control system according to claim 6.
8. A gas burner control and ignition system according to claim 5,
further comprising a gas flow restrictor mounted between the gas
valve and the burner.
9. A gas burner control and ignition system according to claim 5,
wherein the spark control system comprises an electric energy
storage system, and a solar cell charging system.
10. A gas burner control and ignition system according to claim 5,
wherein the spark control system comprises: a) A power supply; b) A
spark generating device; c) An oscillating circuit connected to the
power supply and generating an oscillating circuit; d) An energy
storage device connected to the oscillating circuit; e) An energy
transformer connected to the spark generating device; f) An energy
sensing and triggering circuit, connected to the energy storage
device and connecting the energy storage device to the energy
transformer when sufficient energy is sensed in the energy storage
device.
11. A gas burner control and ignition system according to claim 10,
wherein the power supply comprises a battery, and a solar cell
charging system connected to the battery.
12. A gas burner control and ignition system according to claim 5,
wherein the gas valve supplies gas at a pressure of about 10 pounds
per square inch, and wherein the pressure switch indicates that the
gas valve is open when the output pressure of the gas valves
reaches about 2 pounds per square inch.
13. A gas burner control and ignition system according to claim 5,
wherein the burner has an associated outlet stack exhausting heat
from the burner after passing in proximity to the separator, and
wherein the burner temperature sensor mounts with an outlet stack
of the burner, and wherein the burner temperature sensor indicates
that sufficient heat has been generated when the burner temperature
sensor reaches about 140 degrees Fahrenheit.
14. An oil and gas separator according to claim 7, wherein the
separator vessel comprises a horizontal separator.
15. An oil and gas separator according to claim 7, wherein the
separator vessel comprises a vertical separator.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to the field of oil and gas
separation, specifically to methods and apparatuses for igniting a
burner for controlling heat the temperature of the contents of a
separator.
[0002] Petroleum flowing from a well is not refined product. It is
a mixture of crude oil and gas, and impurities such as brine, sand,
and other suspended solids. The mixture flows into a separator
where gravity can be utilized to separate the mixture into product
(oil, gas) from the impurities. The product is then moved,
generally by pipelines into storage tanks that are close to the
production well(s). From here it is transported to refineries for
processing.
[0003] Some oil wells produce considerable salt water along with
the oil. Gas also bubbles out of the oil. In order to separate the
oil, water, and gas, the fluids can be put into a separator. The
separator is a tank, often using gravity to separate the fluids.
Gas goes to the top, and the heavier salt water goes to the bottom.
In the past, where there was no market for the gas, it was often
flared (i.e. burned at the well site). Today, casing gas is used to
power pump engines or heat storage tanks. Heating the separator can
help separate water and oil if they are mixed in an emulsion.
[0004] Current gas-heated separators use a pilot light to ignite
gas. The pilot light is kept burning by a small flow of gas. The
pilot light ignites the gas in a main burner when a temperature
control system indicates that heating is needed. Pilot light
systems can be very simple, and consequently are currently in
widespread use with oilfield separators, where ruggedness and
simplicity can be important. Alternative ignition systems, in use
in other applications, have not been adopted for oilfield
separators due to their increased cost and complexity.
[0005] Pilot ignition systems must be kept lit and maintained by
human operators. The pilot light can be extinguished by wind or
other weather conditions. Also, the small pilot orifice can be
easily obstructed, e.g., by sand, extinguishing the pilot light.
Cleaning the orifice and relighting it requires time and resources.
Also, if the pilot light is extinguished, then the main burner will
not ignite, and the separator will not be heated. This can lead to
freezes in the separator, interrupting the oil/gas/water flow
through the separator. Interrupted flow results in lost
revenue.
[0006] Accordingly, there is a need for ignition methods and
apparatuses that are sufficiently simple and rugged for oilfield
separator applications, and that avoid the shortcomings of current
pilot light systems.
SUMMARY OF THE INVENTION
[0007] The present invention provides methods and apparatuses for
controlling a heater for an oil and gas separator. According to the
present invention, a spark is provided for igniting a gas burner.
The spark is controlled such that the gas burner is ignited,
without unduly complex control or sensor requirements. In the
description below, generally an entire temperature-controller
separator is described to provide context for the discussion. The
invention also contemplates just the heating subsystem, e.g. to
mount with existing separators. The invention also contemplates
just the heating control subsystem, e.g., to retrofit existing
pilot ignition subsystems.
[0008] Advantages and novel features will become apparent to those
skilled in the art upon examination of the following description
and can be learned by practice of the invention.
DESCRIPTION OF THE FIGURES
[0009] The accompanying drawings, which are incorporated into and
form part of the specification, illustrate embodiments of the
invention and, together with the description, serve to explain the
principles of the invention.
[0010] FIG. 1 is a schematic illustration of an apparatus according
to the present invention.
[0011] FIG. 2 is a schematic illustration of an apparatus according
to the present invention.
[0012] FIG. 3 is a schematic illustration of an apparatus according
to the present invention.
[0013] FIG. 4(a,b) is a circuit diagram of a spark controller
subsystem suitable for use with some embodiments of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present invention provides methods and apparatuses for
controlling a heater for an oil and gas separator. According to the
present invention, a spark is provided for igniting a gas burner.
The spark is controlled such that the gas burner is ignited,
without unduly complex control or sensor requirements. In the
description below, generally an entire temperature-controller
separator is described to provide context for the discussion. The
invention also contemplates just the heating subsystem, e.g. to
mount with existing separators. The invention also contemplates
just the heating control subsystem, e.g., to retrofit existing
pilot ignition subsystems.
[0015] FIG. 1 is a schematic illustration of an apparatus according
to the present invention. A separator vessel 101, such as those
known in the art, is mounted and connected as is common in the art.
A gas burner 102 mounts with the separator vessel 101, for example
by mechanical attachment below the vessel 101 or by other methods
that allow transfer of heat 103 from the burner 102 to the vessel
101. A gas control valve 104 is in fluid communication with a gas
supply and with the burner 102. A vessel temperature sensor 105
mounts with the vessel 101 such that the sensor 105 can generate a
signal representative of the temperature of the contents of the
vessel 101. A burner temperature sensor 106 mounts with the burner
102 such that the sensor 106 can generate a signal indicative of
the heat generated by the burner 102. A spark generator 108 mounts
with the burner 102 such that a spark from the generator 108 can
ignite gas in the burner 102, for example by means of a spark gap
mounted in the path of gas from the burner 102, or a spark gap
mounted in a gas ignition path to the burner 102. A spark control
subsystem 107 enables the spark generator 108 responsive to the two
temperature signals.
[0016] In operation, when the temperature of the contents of the
vessel 101 falls below a determined value, for example a value that
indicates impaired performance or potential flow reduction, the
vessel temperature sensor 105 generates a signal indicating that
heat is needed. That signal initiates gas flow from the gas supply
to the gas burner 102 through the gas control valve 104. That
signal also initiates enablement of the spark generator 108 by the
spark control subsystem 107. The spark generator 108 can generate a
continuous electric discharge, or can generate a periodic discharge
(i.e., a sequence of sparks) to reliably ignite the burner 102.
Ignition of the burner 102 will generate heat 103 therefrom. The
burner temperature sensor 106 generates a signal indicative of the
heat output from the burner, e.g., a signal indicating that the
burner temperature has exceed a determined threshold. The spark
control subsystem 107 then disables the spark generator 108 since
the burner 102 is known to have ignited by the elevated temperature
signal. If the burner 102 loses ignition, then the spark control
subsystem 107 can re-enable the spark control generator 108. After
the burner 102 has supplied sufficient heat to the vessel, the
vessel temperature sensor 105 can generate a signal that indicates
that heat is no longer required, which signal can cause the gas
control valve 104 to cease gas supply to the burner 102 and can
cause the spark control subsystem 107 to disable the spark
generator 108.
[0017] FIG. 2 is a schematic illustration of an apparatus according
to the present invention. A separator vessel 201, such as those
known in the art, is mounted and connected as is common in the art.
A gas burner 202 mounts with the separator vessel 201, for example
by mechanical attachment below the vessel 201 or by other methods
that allow transfer of heat 203 from the burner 202 to the vessel
201. A gas control valve 204 is in fluid communication with a gas
supply and with the burner 202. A vessel temperature sensor 205
mounts with the vessel 201 such that the sensor 205 can generate a
signal representative of the temperature of the contents of the
vessel 201. A burner temperature sensor 206 mounts with the burner
202 such that the sensor 206 can generate a signal indicative of
the heat generated by the burner 202. A valve sensor 209 mounts
with the gas control valve 209 such that it can generate a signal
indicative of gas flow through the valve 209, e.g., by monitoring
gas pressure in the outlet port of the gas control valve 209 or by
monitoring the control signal of the gas control valve 209. A spark
generator 208 mounts with the burner 202 such that a spark from the
generator 208 can ignite gas in the burner 202, for example by
means of a spark gap mounted in the path of gas from the burner
202, or a spark gap mounted in a gas ignition path to the burner
202. A spark control subsystem 207 enables the spark generator 208
responsive to the temperature and valve signals.
[0018] In operation, when the temperature of the contents of the
vessel 201 falls below a determined value, for example a value that
indicates impaired performance or potential flow reduction, the
vessel temperature sensor 205 generates a signal indicating that
heat is needed. That signal initiates gas flow from the gas supply
to the gas burner 202 through the gas control valve 204. The gas
valve sensor 209 indicates that the gas valve 204 is supplying gas
to the burner 202, and initiates enablement of the spark generator
208 by the spark control subsystem 207. A flow restrictive device
(not shown) such as a needle valve, can mount between the valve 209
and the burner 202, which can increase the time from the opening of
the valve 209 and the gas reaching the burner 202 and decrease or
eliminate any time that gas is flowing through the burner before a
spark is generated. The spark generator 208 can generate a
continuous electric discharge, or can generate a periodic discharge
(i.e., a sequence of sparks) to reliably ignite the burner 202.
Ignition of the burner 202 will generate heat 203 therefrom. The
burner temperature sensor 206 generates a signal indicative of the
heat output from the burner, e.g., a signal indicating that the
burner temperature has exceed a determined threshold. The spark
control subsystem 207 then disables the spark generator 208 since
the burner 202 is known to have ignited by the elevated temperature
signal. If the burner 202 loses ignition, then the spark control
subsystem 207 can re-enable the spark control generator 208. After
the burner 202 has supplied sufficient heat to the vessel, the
vessel temperature sensor 205 can generate a signal that indicates
that heat is no longer required, which signal can cause the gas
control valve 204 to cease gas supply to the burner 102, causing
the gas valve sensor 204 to indicate that gas is not being supplied
to the burner 202 and cause the spark control subsystem 207 to
disable the spark generator 208.
[0019] FIG. 3 is a schematic illustration of an apparatus according
to the present invention. A separator vessel 301, such as those
known in the art, is mounted and connected as is common in the art.
A gas burner 302 mounts with the separator vessel 301, for example
by mechanical attachment below the vessel 301 or by other methods
that allow transfer of heat 303 from the burner 302 to the vessel
301. A gas control valve 304 is in fluid communication with a gas
supply and with the burner 302. A vessel temperature sensor 305
mounts with the vessel 301 such that the sensor 305 can generate a
signal representative of the temperature of the contents of the
vessel 301. A spark generator 308 mounts with the burner 302 such
that a spark from the generator 308 can ignite gas in the burner
302, for example by means of a spark gap mounted in the path of gas
from the burner 302, or a spark gap mounted in a gas ignition path
to the burner 302. A spark control subsystem 307 enables the spark
generator 308 responsive to the temperature signal.
[0020] In operation, when the temperature of the contents of the
vessel 301 falls below a determined value, for example a value that
indicates impaired performance or potential flow reduction, the
vessel temperature sensor 305 generates a signal indicating that
heat is needed. That signal initiates gas flow from the gas supply
to the gas burner 302 through the gas control valve 304, and causes
the spark control subsystem 307 to enable the spark generator 308.
The spark generator 308 can generate a continuous electric
discharge, or can generate a periodic discharge (i.e., a sequence
of sparks) to reliably ignite the burner 302. Ignition of the
burner 302 will generate heat 303 therefrom. Heat 303 from the
burner 302 will cause a rise in the temperature of the contents of
the vessel 301. The vessel temperature sensor 305 can generate a
signal that indicates that the temperature of the contents has
risen above a determined threshold, e.g., a threshold that has been
determined to be adequately indicative of reliable burner
operation. The spark control subsystem 307 then disables the spark
generator 308 since the burner 302 is known to have ignited by the
elevated temperature signal. If the burner 302 loses ignition, and
the contents consequently cool, then the spark control subsystem
307 can re-enable the spark control generator 308. After the burner
302 has supplied sufficient heat to the vessel, the vessel
temperature sensor 305 can generate a signal that indicates that
heat is no longer required, which signal can cause the gas control
valve 304 to cease gas supply to the burner 302, and cause the
spark control subsystem 307 to disable the spark generator 308.
[0021] FIG. 4(a,b) is a circuit diagram of an example spark control
subsystem suitable for use with some embodiments of the present
invention. The components are as set forth in Table 1.
TABLE-US-00001 TABLE 1 Q1 MPS77A, NPN transistor D1 1N4004 D2
1N4004 R1 0.462 M.OMEGA. 0.25W resistor T1 Step up transformer
(secondary 200 V) C4 1.mu.F/250 V mylar R4 0.990K.OMEGA. 0.25 W
resistor R5 0.990K.OMEGA. 0.25 W resistor R3 220K.OMEGA. 0.25 W
resistor C2 0.01 .mu.F ceramic disk NE1 Neon trigger lamp D6
NTE5814 rectifier diode SCR1 Silicon control rectifier (400 V) C1
0.0047 .mu.F ceramic disk R6 1 M.OMEGA. 0.25 W resistor Q2 LM317
TO3 package, adjustable regulator R6 240.OMEGA. 0.25 W resistor R7
820.OMEGA. 0.25 W resistor R8 1K.OMEGA. ten turn potentiometer T3
DC ferrous noise filter
[0022] Q1, D1, R1, D2, and T1 provide a self-oscillating circuit,
where the output of the secondary side of T1 is rectified and used
to charge C4 to approximately 200VDC. R5, R4, R3, C2, NE1, D6, and
SCR1 provide a voltage level sensing and trigger circuit. When the
proper voltage is sensed, NE1 fires, which turns on SCR1 and dumps
the voltage built up in C4 across the primary side of pulse
transformer T2, which outputs a high voltage to generate a spark
across the gap of a spark plug. C1 and R6 serve as a ground return
and noise reduction for the high voltage spark (a snubber circuit).
Q2, R6, R7, D6, and R8 all for a charge regulator to keep a three
volt battery charged using a solar panel. T3 provides a noise
filter, to help prevent noise from getting back into the DC
charging circuit.
[0023] The present invention can be used with any gas-powered
separator, including without limitation those marketed by Tesco
Corporation, Allman Heath, Natco, American, and Weatherford. The
invention is suitable for use in inclement weather, with both
vertical and horizontal separators. Contemporary separators are
typically approximately three feet in diameter and approximately
none feet long, although the present invention is not limited to
those sizes.
[0024] The temperature at which the burner is desired is generally
in the range of 80 to 120 degrees Fahrenheit, although the present
invention is suitable for use outside that range. Generally an
output stack temperature of about 140 degrees Fahrenheit indicates
that the burner is ignited, and that the spark generator can be
stopped, although the present invention is suitable for use with
various indications of main burner ignition. In typical
environmental conditions, the time after burner ignition until the
output stack reaches 140 degrees Fahrenheit can be about two to
three minutes.
[0025] In some embodiments of the present invention, a 0.25 inch
needle valve between the main gas valve and the burner to delay the
arrival of gas to the burner. A 2 pound pressure switch was found
to be suitable for initiating the spark circuitry, with a 10 pound
burner supply pressure. A variety of spark devices can be used;
spark igniters like those used in some water heaters can be
suitable. A T12 thermostat made by Kimray was suitable as a
temperature sensor in an embodiment of the present invention. A
bimetallic strip sensor can be used to sense the temperature of the
outlet stack.
[0026] The particular sizes and equipment discussed above are cited
merely to illustrate particular embodiments of the invention. It is
contemplated that the use of the invention may involve components
having different sizes and characteristics. It is intended that the
scope of the invention be defined by the claims appended
hereto.
* * * * *