Patent Application
20230173404
The disclosure relates generally to periodic removal of liquid from a blowpipe.
A blowcase system, or pressure vessel system, is a system that collects fluid, at a relatively low pressure, and then, upon being filled is pressurized with relatively higher pressure gas which causes the collected fluid to exit the pressure vessel through a selected outlet system. The pressure vessel system basically performs the function of a pump, utilizing high pressure gas to displace fluid from the vessel.
Pressure vessel systems are often used in conjunction with flare knockout (KO) drums and are a key component of the flare system. The knockout drum is used to slow down gas flow by creating a pressure drop, allowing liquids and condensate to fall out as condensate of a vented gas stream ahead of combustion in the flaring system.
The condensate is drained to a blowcase which temporarily collects the liquid which is then periodically evacuated from the blowcase to a downstream use. The blowcase often uses a level float to determine the liquid level in the blowcase, which operates by mechanical linkage to move an actuator. In many cases, the actuator operates a switch with a pressurized gas supply for pneumatically moving a switch actuator. The switch actuator operates a three-way pneumatic valve which opens a line from a high pressure motive gas source to the blowcase. The pressurized gas evacuates, or “blows down,” the blowcase of liquid. In some cases the motive gas is natural gas from the facility. One the liquid level has dropped, as measured by the float level, the process is reversed, returning the blowcase to collecting condensate for the next cycle. Similar systems are used as components as pressure-relief systems and condensate removers in various industries.
There are shortcomings to the prior art knockout and blowcase system, including the pressure relief valve assembly, the level float assembly, the mechanical switch, the three-way pneumatic valve, and the difficulty of accessing the interior of the pressure vessel for repairs and maintenance. The blowcase pressure vessel is large enough, per ASME (American Society of Mechanical Engineers) standards, to require certification of design and is required to have a safety pressure relief valve. Relief valves must be routed to a safe area, resulting in additional costs and safety concerns. Further, the relief valve must be periodically taken out of service and tested to ensure it is operating within its design parameters. Servicing and replacement results in added costs associated with shut down time and valve replacement.
The level float in the blowcase is mechanical in nature, as it requires the liquid in the blowcase to move the valve up and down to activate the switch. Level floats are known to “gum up” and stop moving, or to corrode to the point of breaking off. The switch is a mechanically actuated 3-way valve which has been known to wear out and fail, and requires an actuator pressurized gas source. The 3-way pilot valve is pneumatically actuated, often with raw, dirty or wet gas from the wellhead. These pilot valves have been known to “gum up” with the dirty gas and fail to actuate.
Finally, the blowcase does not have an inspection port. Consequently, a user cannot inspect or perform maintenance on the inside of the vessel, in case of debris causing plugging, a float switch breaks off, etc. Some repairs may require removal of the blowcase so it can be turned upside down to try and fish-out debris or a failed float switch, often through a small, 2 inch diameter opening. Alternately, the blowcase must be cut open, such as with a blowtorch, requiring significant repair to place the blowcase back into usable condition. Improvements are needed to overcome these shortcomings.
Drawings of the preferred embodiments of the present disclosure are attached hereto so that the embodiments of the present disclosure may be better and more fully understood, wherein:
An exemplary blowpipe system 100 is seen in
The condensate 114 is drained from the knockout drum 112 via a condensate outlet line 126 at the bottom of the drum to the blowpipe 142. The blowpipe is at a lower elevation so gravity drains condensate to the blowpipe. The condensate outlet line 126 includes a check valve 128 or the like, to prevent condensate from flowing back into the knockout drum 112. The condensate 114 is temporarily stored in the blowpipe 142 having a condensate line 144 in fluid communication with the knockout drum condensate outlet line 126.
A blowpipe assembly 100 is provided downstream from the knockout drum 112. Condensate 114 from the drum flows into the interior space 140 of the blowpipe 142 through condensate line 144. The condensate pools in liquid zone 145. The blowpipe is generally cylindrical. The blowpipe, in some embodiments, is not an ASME pressurized vessel, that is, is not large enough per ASME standards or boiler codes to require meeting certain ASME requirements for pressure vessels. For example, the blowpipe can be a pipe having a six inch diameter or less. ASME Boiler and Pressure Vessel Code does not recognize piping of six inches and smaller as pressurized vessels requiring certification or standards. Consequently, the blowpipe does not require a pressure relief valve or the like. As an unregulated, non-certified pressure vessel, the blowpipe does not require a U-stamp. Further, no maintenance, testing or replacement of a relief valve is required. The blowpipe, for example, can be fabricated from Schedule 40 (“SCH 40”) six inch diameter pipe.
The blowpipe 142 is capped with an end cap 143, such as a blind flange or cover, which is easily removed or opened for maintenance and repair of the blowpipe and its interior components. The end cap is easily removable and replaceable by fasteners known in the art, such as bolt and nut assemblies and the like. The end cap can be, for example, an American National Standards Institute (ANSI) 150 RF flange. Removal or opening of the end cap grants the user easy access to the interior of the blowpipe and accessories therein.
The blowpipe, in some embodiments, utilizes an inlet splash plate 193 that controls flow of condensate into the blowpipe. The splash plate is designed and positioned to reduce the potential for splashing, waves, and other undesirable flow patterns that could disrupt the system, prematurely or irregularly trigger evacuation of the blowpipe, etc.
The blowpipe assembly 100 includes a condensate level sensor assembly 190 for detecting the condensate level in the blowpipe. The condensate level assembly comprises a high-level tuning fork sensor 194 and a low-level tuning fork sensor 196. A tuning fork vibrates at its known resonance frequency. In the sensor device, the tuning fork vibrates in response to electric power, such as by a piezoelectric device. When the tuning fork is in contact with the liquid condensate, the resonant frequency of the fork changes. A change in frequency is detected by the sensor device and an appropriate electrical signal is sent by the device. Tuning fork level sensors are commercially available. The high-level tuning fork sensor is mounted with the tuning fork extending into the blowpipe to a preselected high level. Similarly, the low-level tuning fork sensor is mounted is mounted with the tuning fork extending into the blowpipe to a preselected low level. The control and upper portions of the tuning fork sensors may extend to the exterior of the blowpipe. The tuning fork sensors used as fill indicators eliminate the need for a float valve. The tuning fork level sensors are more robust than float valves. The tuning fork level sensors are preferably made entirely of stainless steel so there is low corrosion potential and no linkage or physical actuator parts to fail.
The tuning fork level sensors 194 and 196 are electrically or wirelessly connected or connectable to an electric controller 198 which can receive electrical signals, such as analog electrical signals, digital signals, Bluetooth signals, Wi-Fi signals and the like, from the tuning fork sensors. The electric controller 198 is operable to activate an electrically actuated three-way valve assembly 200. The controller and valve are electrically or wirelessly connected or connectable. Use of a microswitch is eliminated in such an embodiment. The controller 198, which can be an assembly of connected or operable elements, in some embodiments sends monitoring signals or alerts to the user, preferably wirelessly to a receiving device at a location readily accessible to the user. The controller allows the user to remotely monitor the system for any abnormal conditions and can send an alert to the user.
A three-way electrically activated valve assembly 200 is operated by a controller 198 by electrical signal between the controller to the valve. The three-way valve assembly 200 fluidly, and selectively, connects a pressure equalizer line 172 which extends into the interior of the knockout drum 112 in the gas zone 120, a blowpipe gas inlet line 174 which extends into the blowpipe interior, and a motive gas pressure source 176. The motive gas pressure source can be, for example, relatively higher pressure gas from the facility, or gas from sources which have been pressurized by a pump or compressor. The use of an electrically actuated three-way valve results in a lower potential for the valve to “gum up” or fail, especially when flowing raw, dirty or wet process gas.
A condensate discharge line 180 is provided, fluidly connected to the blowpipe condensate line 144 and knockout drum condensate outlet line 126 for discharging the condensate to a downstream location, such as a storage tank. The discharge line 180 can include a check vale 182 to prevent condensate from backing through the discharge line.
When the blowpipe assembly 140 is in an equalizer mode, or exhaust mode, the interior pressures of the knockout drum and blowpipe are equalized via communication of pressure between the drum and blowpipe by the equalizer line 172 and gas inlet line 174 through the three-way valve 200. The gas pressure is communicated through the line 172, three-way valve 200, gas inlet line 174 to the blowpipe 142.
Once the condensate liquid level in the blowpipe rises to contact the high level tuning fork sensor 194 at a preselected height, the sensor 194 sends a signal to the controller 198. The controller 198, in turn, sends a signal to electrically actuate the three-way valve 200. This changes the three-way valve 200 to actuation or “blow down” mode, in which the three-way valve 200 cuts pressure communication between the drum 112 and blowpipe 142 and opens fluid communication of the motive force gas from the motive gas source 176 to the blowpipe. The motive force gas is a relatively high-pressure gas which flows through the valve 200 and into the blowpipe 142. The motive pressurized gas evacuates the condensate out of the blowpipe to, for example, facility tanks through the condensate line 144 and discharge line 180. Check valve 182 prevents condensate from traveling back to the knockout drum.
Once the condensate has been evacuated to a preselected level, the process is reversed, placing the system in equalization mode once again. As the condensate level is blown down, the condensate level falls until the low level tuning fork sensor 196 is no longer in contact with the condensate in zone 145. The low level tuning fork sends a signal to the controller 198, and the controller sends a signal to actuate the three-way valve. The valve moves to equalization mode, cutting off the motive gas and opening fluid connection between the knockout drum and blowpipe, again equalizing pressure across the blowpipe and drum. Condensate from the drum drains into the blowpipe again and the process repeats.
The blowpipe 142 is seen as a cylindrical vessel, six inches in diameter and having a removable six inch blind flange 143 for ease of access, maintenance and repair. The blind flange 143 has a plurality of bolt holes which cooperate with corresponding bolt holes defined in a flange 146 on the blowpipe. Bolt and nut assemblies 148 are utilized to secure and remove the end cap from the blowpipe.
A condensate outlet line 126 from the knockout drum has a check valve 128 and is fluidly connected to condensate inlet line 144 of the blowpipe assembly. The condensate inlet line 144 is fluidly connected to the blowpipe 142 at an inlet to deliver condensate to the blowpipe interior. A condensate outlet line 147 of the blowpipe 142 is fluidly connected to the interior of the blowpipe and to the condensate discharge line 180, which has a check valve 182. Also present is a manual isolation valve 183. A splash plate 193 is mounted in the interior of the blowpipe, positioned adjacent the condensate port 191.
A high level tuning fork sensor assembly 194 and a low level tuning fork sensor assembly 196 are mounted to the blowpipe 142 with the tuning forks 195 and 197, respectively, extending into the interior of the blowpipe to selected levels. As condensate fills the blowpipe, the low level tuning fork 197 will contact the liquid, the ends of the fork in the condensate. As the blowpipe continues to fill, the high level tuning fork ends will contact the rising condensate, triggering a signal from the tuning fork assembly to a controller 198. Similarly, as the liquid level falls during blow down, the low level tuning fork ends will eventually at the level of the condensate. The low level tuning fork sensor sends a signal to the controller to return the system to the equalization mode.
A three-way electrically operated valve 200 is operated by a controller and movable between an equalizer mode, in which fluid communication is established between the interiors of the knockout drum and the blowpipe, and a blow down or actuation mode, in which fluid communication is established between a high pressure motive gas source and the interior of the blowpipe. The electrically operated three-way valve 200 includes an electrical connection 201 for connecting to a power source and/or a controller.
Also seen in
The three-way valve assembly 200 has an equalizer gas inlet line 204 for fluid connection to the equalizer line 172, and a motive gas inlet line 206 for fluid connection to the pressurized motive gas source 176. Isolation valves 208 and 210 are provided, respectively, for further control of the inlet lines. A valve manifold or body 212 fluidly connects to the inlet lines and the gas inlet line 174 which provides fluid connection to the interior of the blowpipe 142 at a connector 214. An actuator 211 is mechanically coupled to the manifold or valve body 212. An isolation valve 216 is provided for further control of the piping assembly.
The three-way valve assembly 200 includes, in an exemplary embodiment, a manual bypass assembly 220 having a bypass equalizer gas line 222 with isolation valve 224, a bypass motive gas line 226 with isolation valve 228, and a bypass gas feed line 230 which fluidly connects to the gas inlet line 174.
The apparatus and systems disclosed herein are described for use with a flare knockout drum specifically, and in the oilfield in general. Persons of skill in the art will understand that the apparatus and systems can also be used in any application wherein it is desirable to remove condensate or other liquid from a process vessel.
While the foregoing written description of the disclosure enables one of ordinary skill to make and use the embodiments discussed, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiments, methods, and examples herein. The disclosure should therefore not be limited by the above-described embodiments, methods, and examples. While this disclosure has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the disclosure will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
This is a U.S. Non-Provisional Application claiming priority to the earlier-filed U.S. Provisional Application Ser. No. 63/287,488, filed Dec. 8, 2021.
| Number | Date | Country | |
|---|---|---|---|
| 63287488 | Dec 2021 | US |
