CN117262521A - Floating roof monitoring system for monitoring floating roof oil storage tank - Google Patents
Floating roof monitoring system for monitoring floating roof oil storage tank Download PDFInfo
- Publication number
- CN117262521A CN117262521A CN202311415576.XA CN202311415576A CN117262521A CN 117262521 A CN117262521 A CN 117262521A CN 202311415576 A CN202311415576 A CN 202311415576A CN 117262521 A CN117262521 A CN 117262521A
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- Prior art keywords
- floating roof
- monitoring
- floating
- measurement
- circuit
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Links
- 238000007667 floating Methods 0.000 title claims abstract description 135
- 238000012544 monitoring process Methods 0.000 title claims abstract description 61
- 238000004146 energy storage Methods 0.000 claims abstract description 24
- 238000005259 measurement Methods 0.000 claims abstract description 24
- 238000004891 communication Methods 0.000 claims abstract description 14
- 231100001261 hazardous Toxicity 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims description 22
- 238000001514 detection method Methods 0.000 claims 1
- 238000000691 measurement method Methods 0.000 claims 1
- 239000003921 oil Substances 0.000 description 25
- 238000000034 method Methods 0.000 description 6
- 239000007789 gas Substances 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000003209 petroleum derivative Substances 0.000 description 2
- 238000009428 plumbing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D90/00—Component parts, details or accessories for large containers
- B65D90/48—Arrangements of indicating or measuring devices
- B65D90/50—Arrangements of indicating or measuring devices of leakage-indicating devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D88/00—Large containers
- B65D88/34—Large containers having floating covers, e.g. floating roofs or blankets
- B65D88/36—Large containers having floating covers, e.g. floating roofs or blankets with relatively movable sections
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D90/00—Component parts, details or accessories for large containers
- B65D90/48—Arrangements of indicating or measuring devices
Abstract
The present patent invention is a floating roof monitoring system for monitoring a floating roof oil storage tank that determines the local condition of the floating roof in spaced apart sensing element locations. In a hazardous or potentially hazardous environment, an on-board subsystem including a sensing element in each sensing element location, an intrinsically safe measurement circuit coupled with the sensing element and configured to determine the local status, an intrinsically safe radio communication on-board circuit coupled for communicating locally on the outside of the on-board subsystem, an intrinsically safe power circuit connected to an intrinsically safe and interchangeable energy storage unit for powering the on-board subsystem. The system further comprises a monitoring circuit for receiving an indication of the local state and for determining an overall monitoring state of the floating and further radio communication circuits. The floating roof subsystem is wireless in terms of power and communications.
Description
Technical Field
The invention discloses a floating roof monitoring system for monitoring a floating roof oil storage tank, and particularly relates to a monitoring system for monitoring a floating roof of a floating roof tank and a monitoring method for monitoring the floating roof of the floating roof tank.
Background
In large liquid tanks capable of containing large amounts of petroleum products, particularly fuels and tanks at refineries and the like, floating roofs are often used, which float on the liquid in the tanks and are therefore movable in a vertical direction. Thus, the floating roof is able to follow the level of the liquid (oil product) for position adjustment as the crude oil is drained from or filled into the tank. This type of floating roof is used to prevent leakage of steam and gas from the tank into the atmosphere, and for example rain water from the surrounding environment into the liquid. Avoidance of leakage and ingress is enhanced by sealing means mounted along the perimeter of the floating roof for providing sealing and sliding contact with the inner wall of the tank. Furthermore, the use of a floating roof floating on the liquid minimizes the space between the liquid and the roof, thereby minimizing the amount of liquid in the form of gas and vapor in the space. For a tank that is full of oil, the environment at the top of the floating roof also presents a potential risk.
Floating roofs for these purposes are usually manufactured as large steel structures with a floating function (pontoon), weighing about 100 tons and having a diameter of several tens of meters. Regarding size and environmental aspects, it is important to monitor the normal operation of the floating roof and the undisturbed floating in order to identify disturbances thereof as early as possible. Therefore, it is also important to limit any interruption of floating roof monitoring. When product is introduced into the tank, a portion of the floating roof may become stuck to the inner wall of the tank. As the input work proceeds, the floating roof will be partially submerged by the liquid, so that if the gas or vapor produced is explosive or otherwise dangerous, some potentially dangerous situation may occur.
During tank discharge, a portion of the floating roof may become stuck to the tank inner wall. As the discharge proceeds, a considerable amount of air may enter the space between the liquid and the floating roof. If a collapse of the floating roof occurs, oil and the top of the collapsed floating roof may form an explosion.
To minimize evaporation of liquid in floating roof tanks, the process tends to become more stringent. Higher friction is often provided in the design in the sealing arrangement between the perimeter of the floating roof and the inner wall of the tank. The increase in friction may increase the risk of the floating roof getting stuck. For many years, problems like those described above have attracted attention from the petroleum industry. The need for systems to address these issues appears to be increasing.
In the monitoring of potentially dangerous environments of floating roofs, besides realizing effective installation and providing safe and reliable monitoring functions, the invention can furthest prolong the service life of a monitoring system, reduce the maintenance of any system and minimize the downtime of any system, and also can avoid the unnecessary complexity of the monitoring system.
The present invention aims to provide a wireless monitoring system where communication is monitored wirelessly from a floating roof and power is provided on the floating roof by an energy storage unit, such as a long life battery. According to the invention, such energy storage units need to be interchangeable in a field environment with fuel or fuel tanks, i.e. in a potentially dangerous environment. One reason for this is that the lifetime of the other components of the monitoring system can be designed to be much longer than the lifetime of the energy storage units known hitherto. The energy storage units need to be easily interchangeable. Another reason is that the most frequent maintenance of the floating roof mounted equipment of the monitoring system requiring physical access can be foreseen to re-power the wireless operating equipment of the system. Another reason is that the field environmental changes of the energy storage unit will only have as little system downtime as possible.
The present invention provides systems and methods for monitoring the floating roof of a floating roof tank and technically implementing interchangeability of one or more energy storage units, and methods for powering wireless devices.
More specifically, the present invention provides a monitoring system for monitoring a floating roof of a floating roof tank containing oil and having a bottom, a cylindrical wall, a floating roof floating on the oil, wherein a local condition of the floating roof is measured at least three spaced apart sensor element locations of the floating roof.
The monitoring system further includes a floating roof subsystem, at least one intrinsically safe measurement circuit and at least one internal safe measurement circuit, the floating roof subsystem including at least three sensing elements, wherein one of the sensing elements is fixed in each of the spaced apart sensor element locations on the floating roof, wherein each of the sensing elements is coupled to the at least one measurement circuit for determining a local status location of each of the sensor elements on the floating roof in the at least one measurement circuit, at least one intrinsically safe floating roof radio communication circuit coupled to at least one of the measurement circuits and including an external communication for the system on the floating roof, at least one indicated communication antenna for the local status, at least one safe power circuit for powering the measurement circuits and the radio communication circuits, and having a power circuit connection interface, and at least one secure and interchangeable energy storage unit having an energy storage interface coupled to the power circuit connection interface.
The monitoring system further comprises a monitoring circuit for receiving an indication of the local status from each sensor unit and for determining an overall monitoring status of the floating roof based on at least one indication of the local condition.
The monitoring system further comprises an off-floating roof subsystem comprising a radio communication off-floating roof circuit arranged to communicate wirelessly with at least one of the sensor units and arranged to communicate at least one indication of the local state or the monitored overall state of the floating roof externally of the off-floating roof subsystem.
In order to be able to actually achieve the interchangeability of the energy storage units according to the invention, there are electrical parameters defined for the power circuit connection interface and the energy storage unit connection interface. These parameters are matched to each other in an intrinsically safe environment so that the energy storage unit can be coupled and decoupled from the power supply circuit in a safe manner in potentially hazardous environments present on top of the floating roof.
According to the invention, the interchangeability of the energy storage unit is enhanced by the power circuit connection interface having the power circuit electromechanical contact terminal and the energy storage unit electromechanical contact terminal. In operation, each of these terminals are held in conductive electrical contact with each other through the interfaces of the power circuit and the energy storage unit, respectively. By releasable pressure means, such as screw caps, fastening screws, latching mechanisms or the like, in order to provide interchangeability of the energy storage units.
In monitoring the top of the buoyancy tank it is considered to be very helpful to know the relative height of the top at the sensing location, and for practical reasons the relative heights of their respective reference points and the local height of the liquid. Such relative level measurement provides a direct information of how the floating roof floats in the liquid at each sensing element position and has the opportunity to generate a warning that the floating condition has become abnormal earlier than, for example, monitoring the overflow of the floating roof.
Providing the level as a base level measurement function of the local status may include indicating that the local level reading falls within a high level range or a low level range. This will enable conclusion that the floating roof floats exceptionally low (possibly leaking out of the floating element of the floating roof) or exceptionally high (possibly adhering to the tank wall at the time of draining the liquid), respectively. It would be advantageous to supplement both classes of levels with a mid-range. When the communication local level reading falls within such a range, the local state will indicate a normal float in the problematic sensing element location.
Drawings
Fig. 1 shows a monitoring system of an embodiment of the invention.
Fig. 2 shows a radar level gauge according to another embodiment of the present invention, mounted in a support opening of a floating roof.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, the embodiment of the present invention is applied to a large floating roof tank 1 having a bottom 2 and a side wall 3. The tank 1 is made of steel and has a diameter of several tens of meters. The tank contains petroleum products 4, on top of which a floating roof 5 floats by means of a float (not shown) integral with the floating roof 5. The floating roof 5 has seals (not shown) along its periphery for restricting the passage of liquids and gases between the floating roof 5 and the interior of the side wall 3. As will be appreciated by those skilled in the art, the floating roof tank 1 and its associated equipment may further include plumbing fixtures, plumbing, valves, actuators for oil filling and draining, and various measurement and control devices, etc. In particular, the tank 1 is equipped with an oil level gauge 6, the oil level gauge 6 measuring the filling level of the oil 4 with respect to a reference point of the tank 1, such oil level gauge 6 being typically mounted on top of a stationary pipe 7, the stationary pipe 7 being a pipe arranged vertically from the top of the side wall 3, through an opening in the floating roof 5 and through the oil 4 towards the bottom 2. The floating roof 5 floats generally horizontally on the oil 4 and follows the oil level during filling or draining. However, as described herein, such normal floating may fail under various conditions and for various reasons. Determining faults at an early stage is of great importance, since capsizing, sinking, breaking or other resulting faults can be avoided by appropriate measures. These include stopping the filling or draining of oil, refilling or draining a certain amount of oil, rapidly draining the tank to a mechanically supported oil level on the float roof, and alerting personnel working in the tank environment.
It has been inferred that a particularly quick and accurate method of determining whether a fault has occurred in the floating of the floating roof 5 involves installing radar level gauges 8 at several spaced apart sensing locations 9 on the floating roof 5. These level gauges 8 measure the local state of the respective sensing locations 9 as the level of the oil 4 with respect to the vertical reference point of the floating roof in the respective sensing locations 9. The level measurement may be continuous over the relevant range or at least have a switching characteristic of an abnormally high level and an abnormally low level. The tank 1 is equipped with a monitoring system 10 for monitoring the floating roof 5. The monitoring system 10 is intended to measure a local state, indicated in each sensing position 9 as local oil level with respect to said floating roof 5. The monitoring system 10 then determines the overall state of the floating roof 5 based on the local oil level. Such an overall state may include a normally floating or abnormally floating state, where the abnormally floating state includes a combination of out-of-range level values and their respective sensed positions. The foregoing may even be further processed to determine the occurrence of one of several predetermined fault float conditions of the floating roof 5. Oil level measurements are made in at least three spaced apart sensing element locations 9 of the floating roof 5. The preferred sensor element position 9 will vary depending on the specific mechanical design of the floating roof 5 and the tank 1. It is presently believed that the most preferred sensing element locations are off-centered on the floating roof and distributed as evenly as possible and near the periphery of the floating roof. However, for the post-installation of the monitoring system in an already running tank 1, it would be very advantageous to use the opening 10 already present in the floating roof 5 as a sensing element positioning. Such an opening 10 that has been made may comprise an opening for the top leg 11 or other openings, such as various inspection openings, typically with a lid mounted during operation of the floating roof tank. The roof legs 11 are typically used to support the floating roof 5 at a minimum level when the oil 4 in the tank is completely emptied.
The monitoring system has a subsystem. The subsystem comprises a radar level gauge 8. Each of these units is located at one of the sensing element positions 9. The number of sensing element positions 9 and the number of level gauges 8 are determined by the specific design of the floating roof tank 1 and the floating roof 5. A larger floating roof may require more sensing element positions 9 and level gauges 8 than a smaller floating roof. However, it is believed that three of each is the minimum number, although in many cases it may be a sufficient number entirely, particularly if its distribution is substantially equidistant along the perimeter of the floating roof 5. Since the position selection sensing element position may be limited to a position where the floating roof 5 already has an opening 10 from the top side to the bottom side of the floating roof, a greater number of sensing element positions and level measuring units may be used if the position of the sensing element is less advantageous from a monitoring point of view. In the most preferred embodiment of the invention, the level measuring unit is a radar level gauge 8 of the type using a single-conductor or two-conductor probe 12 as sensing element. The probe 12 acts as a waveguide and is typically partially immersed in the oil 4 of the tank 1. In this sense, radar is understood to be an indication that the level measuring unit is operating by sending and receiving electromagnetic signals along the probe. There will be a reflection of the transmitted electromagnetic signal at any significant change in the impedance of the signal propagating along the probe 12, for example, where it penetrates the surface of the oil 4. By determining the time for the signal to travel to the surface and back (at a known speed), the radar level gauge 8 will determine the distance to the surface. Several different radar level measuring methods of signal generation and processing are known and may be used in the system of the present invention. Non-contact radar level gauging may also be used, wherein electromagnetic signals are transmitted and received through the measuring antenna.
The system also has a monitoring circuit for receiving said indication of said local status from each radar level gauge 8. According to one embodiment of the invention, the monitoring circuit may be at least partially comprised in each radar level gauge 8. In fact, it is preferred that the radar level gauge 8 is able to determine and communicate individually in case the local state at the sensing element position 9 exceeds the normal limit. A part of the monitoring system is preferably outside the radar level gauge 8 or arranged as a subsystem distributed in each radar level gauge. This part of the monitoring system is adapted to determine an overall monitoring state based on the level value of the floating roof or other local state determined in each radar level gauge. In order for the system to communicate the local level value, other local state or the global state of the floating roof, the system also has, as part of the off-roof subsystem, a radio communication off-roof circuit 15, which radio communication off-floor circuit 15 is arranged to communicate wirelessly with at least one of the radar level gauges 8 and to communicate said level or state to a higher level control system 16, typically accessible via a radio gateway 17 to the environment of the floating roof tank.
Claims (8)
1. A floating roof monitoring system for monitoring floating roof oil storage tank, its characterized in that: the floating roof tank contains a liquid and has a bottom, a cylindrical wall, a floating roof floating on the liquid, the system being arranged to determine a local state of the floating roof at least three spaced apart sensing element locations of the floating roof, and the system comprising a floating roof subsystem comprising: at least three sensing elements, wherein one of the sensing elements is fixed in each of the spaced apart sensing element positions on the floating roof; at least one intrinsically safe measurement circuit, wherein each of the sensing elements is coupled to at least one of the at least one measurement circuit for determining the local state location of each of the sensing elements of the floating roof within at least 1 measurement circuit; comprising at least one of the at least one measuring circuit coupled thereto and comprising a communication antenna, at least one intrinsically safe power supply circuit for powering the at least one measuring circuit and the at least one radio communication circuit and having an intrinsically safe power supply circuit connection interface, wherein at least one of the at least one raw interchangeable energy storage units is capable of being decoupled in the hazardous or potentially hazardous environment present on the floating roof by separating the respective raw energy storage unit connection interface from the respective power supply circuit connection interface, wherein each power supply circuit connection interface, each raw energy storage unit connection interface has matched interface parameters.
2. A floating roof monitoring system for monitoring a floating roof oil storage tank according to claim 1, said power circuit connection interface and said energy storage unit connection interface having matching electrical parameters for decoupling said energy storage unit from the power circuit in an intrinsically safe manner in a hazardous environment.
3. A floating roof monitoring system for monitoring a floating roof oil storage tank as claimed in claim 1, wherein: the power circuit connection interface comprises electromechanical contact terminals and the energy storage unit connection interface comprises an energy storage unit, the electromechanical contact terminals being arranged to be in electrically conductive electrical contact with corresponding power circuit electromechanical contact terminals by releasable pressure means, facilitating interchangeability of the energy storage unit.
4. A floating roof monitoring system for monitoring a floating roof oil storage tank as claimed in claim 1, wherein: the sensing element and measurement circuitry are arranged to determine the oil as a local condition relative to the level of the floating roof and to communicate an indication that the level falls within a high level range or a low level range.
5. A floating roof monitoring system for monitoring a floating roof oil storage tank as claimed in claim 1, wherein: the sensing element and the measuring circuit are arranged for determining the level of the liquid relative to the floating roof as a local state and for conveying a continuous indication of the liquid level with a predetermined accuracy belonging to the range of 0.0001-0.1 meter.
6. A floating roof monitoring system for monitoring a floating roof oil storage tank according to claim 1, wherein the sensing element and the measurement circuit are arranged to determine the oil as a local condition with respect to at least one threshold level of the floating roof and to transmit at least an indication of the at least one threshold level, and wherein at least one threshold level value of the at least one threshold level is adjustable by mechanical or electrical means.
7. A floating roof monitoring system for monitoring a floating roof oil storage tank according to claim 1, further comprising a local emergency shutdown device arranged to control at least one of a pump and a valve associated with operation of the floating roof tank in dependence on at least one indication of a local state of the floating roof or a monitored general state, the radio off-roof circuit being arranged to transmit at least one of the indication of the local state or the monitored general state of the floating roof to the emergency shutdown device.
8. A floating roof monitoring system for monitoring a floating roof oil storage tank according to claim 1, said sensing element operating according to at least one measurement technique of said group comprising: continuous non-contact radar liquid level measurement, switch non-contact radar liquid level measurement, continuous guided wave radar liquid level measurement, guan Daolei liquid level measurement, laser measurement, inclinometer measurement and gas detection measurement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311415576.XA CN117262521A (en) | 2023-10-30 | 2023-10-30 | Floating roof monitoring system for monitoring floating roof oil storage tank |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311415576.XA CN117262521A (en) | 2023-10-30 | 2023-10-30 | Floating roof monitoring system for monitoring floating roof oil storage tank |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117262521A true CN117262521A (en) | 2023-12-22 |
Family
ID=89204406
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311415576.XA Pending CN117262521A (en) | 2023-10-30 | 2023-10-30 | Floating roof monitoring system for monitoring floating roof oil storage tank |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117262521A (en) |
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2023
- 2023-10-30 CN CN202311415576.XA patent/CN117262521A/en active Pending
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