DESC:FIELD
The present disclosure relates to a method and an apparatus for emergency evacuation of LPG from a pipeline system from a leaking section.
DEFINITIONS
Liquefied petroleum gas (LPG): LPG is a mixture of light hydrocarbons, primarily C3 and C4 derived from crude oil or crude oil equivalent, which is gaseous at ambient temperature and atmospheric pressure, is liquefied at ambient temperature with application of moderate pressure. The specification of LPG will be governed by IS: 4576.
Cross-country LPG pipeline: Cross-country pipeline means the entire pipeline located beyond the boundary of any facility and its associated facilities which are required for transportation of LPG from one point to another.
LPG pipeline system: An LPG pipeline system includes all facilities including the pipeline associated with transfer of LPG defined above.
Originating pump station: An originating pump station is the first installation having facilities such as booster pumps, mainline pumps etc. for boosting the pressure of the liquid to be transported so that it reaches to next station.
Intermediate pump station: An intermediate pump station is any installation having facilities such as pumps etc. between originating pump station and terminal / final / last delivery station on the pipeline for boosting the pressure of the liquid so that it reaches to next station.
Sectionalizing valve (SV): Sectionalizing valve can be a motor operated valve (MOV) or a hand operated valve (HOV) used in a cross-country pipeline system for isolation of particular pipeline section whenever required.
Inertization process: Inertization, or inerting, is defined as an explosion protection process that uses inert gas to prevent the formation of an explosive mixture.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Liquefied petroleum gas (LPG) due to its inherent properties is susceptible to fire, explosion and other hazards. Such hazards can have an impact on surrounding property, equipment, plant personnel and public. Transportation of LPG through pipeline has become a preferred mode for long distances over conventional modes such as transportation via rail/ road, due to safety and environment-friendliness.
During the transfer of LPG in a cross-country pipeline, in case of any damage or rupture to the cross-country pipeline, LPG will leak out of the pipeline. In order to isolate the affected section, sectionalizing valves which are installed en-route the cross-country pipelines are utilized. The sectionalizing valves which are upstream and downstream of the pipeline of leaking section are closed and the section is isolated in case of a leak.
However, the LPG remaining in the damaged or leaking section are to be emptied out, which otherwise poses a threat as the LPG keeps gushing out continuously from the point of rupture. The LPG coming out of the damaged pipeline can lead to formation of an LPG vapour cloud which, on in contact with a source of ignition, can cause severe damages and can affect lives, property and environment.
Thus, there is felt a need for a method and an apparatus for obviating loss of liquefied petroleum gas in a cross-country pipeline during a leak.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a method and an apparatus that obviates the loss of LPG from a cross-country pipeline system from a leaking section during an emergency evacuation.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a method for evacuating LPG from a leaking section of a cross-country pipeline in response to leaking of LPG from the leaking section. The method comprises the following steps:
• isolating the leaking section of the pipeline by closing a valve immediately downstream of the section and a valve immediately upstream of the section;
• transporting a pumping unit including a pump, a suction hose and a discharge hose to a sectionalizing valve (not shown in figure) of the leaking section by a vehicle, the sectionalizing valve being located near to the leaking section;
• clamping the suction hose to suction of the sectionalizing valve and clamping the discharge hose to an LPG storage or to the next section of the pipeline in a leakproof manner;
• priming and inertization with Nitrogen of the pumping unit to ensure absence of air; and
• pumping under suction, LPG from the leaking section by the pump into the LPG storage or to the next section of the pipeline.
In a preferred embodiment, the pump is driven by the engine of the vehicle and is configured to handle LPG in liquid, vapour or fluid state.
In a preferred embodiment, dampening of vibrations is achieved by anti-vibration mounts provided on the skid of the vehicle.
In a preferred embodiment, measuring of flow of LPG fluid is conducted by a multiphase flow meter.
In a preferred embodiment, the method includes detecting fire or gas with fire and gas detectors.
The present disclosure discloses an apparatus for evacuating LPG from a leaking section of a pipeline in response to leaking of LPG from the leaking section, the apparatus comprising a pumping unit mounted on a vehicle. The pumping unit comprises a pump, a suction hose configured to be detachably attached between the leaking section and the pump and a delivery hose configured to be detachably attached between the pump and an LPG storage; and a power transfer module configured to draw power from the vehicle and supply to the pumping unit.
In a preferred embodiment, the engine of the vehicle is used as prime mover for the pump and is configured to handle LPG in liquid, vapour or fluid state.
In a preferred embodiment, the suction hose and the delivery hose are flexible.
In a preferred embodiment, anti-vibration mounts are provided under a skid for dampening vibrations incident from the apparatus with the skid mounted on the vehicle.
In a preferred embodiment, a multiphase flow meter is provided on the apparatus for measurement of LPG flow.
In a preferred embodiment, a telescopic jib crane is mounted on the apparatus for handling the suction hose and the delivery hose.
In a preferred embodiment, the apparatus includes a hydraulic motor, a hydraulic reservoir, a cooler and a closed-loop variable displacement pump.
In a preferred embodiment, the apparatus is provided with fire and gas detectors.
In a preferred embodiment, the LPG storage is a mobile storage such as a vehicle.
In an alternate embodiment, the LPG storage is a storage configured to be in fluid communication with the pipeline.
In an alternate embodiment, the vehicle is a road transport vehicle.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A method and an apparatus for evacuating LPG from leaking sections of cross-country pipeline, of the present disclosure, will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates the system for evacuating LPG from pipeline in accordance with the present disclosure.
LIST OF REFERENCE NUMERALS
1000 apparatus for evacuating LPG
102 vehicle
103 power transfer module
104 pump
106 suction hose
108 delivery hose
110 hydraulic motor
112 hydraulic reservoir
114 pump control panel
116 jib crane
118 instrumentation skid and PLC system
120 flowmeter
DETAILED DESCRIPTION
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Description of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practised and to further enable those of skill in the art to practise the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiment herein.
The description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
LPG leakage from a pipeline is a high-level emergency with an off-site impact which could be catastrophic and is likely to affect population, property and environment. In case of leak of LPG in a cross-country pipeline, it is of utmost priority to evacuate or transfer LPG from the rupture/leaking section to the next section immediately to prevent LPG continuously leaking out of the point of pipeline rupture.
A method for evacuating LPG from a section of an LPG cross-country pipeline during an emergency like a pipeline rupture or a leak, of the present disclosure, is disclosed. The method comprises the following steps:
• As soon as a pipeline leak is detected in the cross-country pipeline, emergency shutdown procedure gets enabled. The leaking section where the leak has occurred is identified. The upstream and downstream valves located immediately adjacent of the leaking section thereof are closed, to isolate the leaking section. A sectionalizing valve (not shown in any figure), which is a valve located in the nearest location of the leaking section is then idenified.
• A mobile multiphase transfer pump 104 is transported to the nearest sectionalizing valve which is either located upstream or downstream of the pipeline leaking section.
• The suction hose 106 of the sectionalizing valve and the discharge hose 108 is clamped to the LPG storage. In another emdbodiment, the suction hose 106 and the discharge hose 108 are connected to a next adjacent section of the pipeline in a leakproof manner.
• The pump is then primed with the LPG. The environment within the pumping unit is made inert by inertization with Nitrogen. This priming and inertization ensures absence of unwanted atmospheric air, as well as other particulate matter.The engine of the vehicle 102 is then connected to the power take-off (PTO) unit 103 which in turn is connected to the hydraulic motor 110.
• The hydraulic motor 110 then runs the multiphase pump 104 and starts pumping the LPG into the next section by suction, thereby, continuing to empty the pipeline until the LPG in the leaking section is entirely removed out of the pipeline.
• In case of difficulty in evacuation to the next pipeline section, the discharge hose can also be hooked upto another LPG storage tanker, from where LPG can be evacuated.
• The multiphase pump 104 immediately evacuates the LPG from the pipeline section and the LPG pipeline is then accessible for clamping and arresting further leak.
Thus, the method of the present disclosure can be used during the transfer of the LPG from a cross-country pipeline in case of an emergency.
The method of the present disclosure is capable of:
• Evacuating LPG from a section of a pipeline into the next section or to a tanker for evacuation of LPG; and
• Obviating the release of LPG into the environment, thereby preventing major mishaps from occurring.
An apparatus for following the method is required which is compact, reliable, robust, shock/vibration resistant, which can be quickly set up, which is suitable for zone-1 classified hazardous area, which is suitable for at least 36 hours of continuous operation, which is suitable for 50% gas volume fraction (GVF), 200 kl/hr of flow rate, has minimum suction pressure of 3 kg/ cm2, which does not need utilities (e.g. compressed air) to be made available, which facilitates ease of operations and which has a centralized control for safe operations.
The present disclosure discloses an apparatus 100 comprising a mobile multiphase transfer pump package mounted on a vehicle, that can be deployed in exigencies for evacuation or transfer of LPG. A multiphase pump is capable of handling all the fluid phases, i.e., liquid, vapour and a mixture of the two phases. The emergency mobile multiphase LPG transfer pump package basically functions to evacuate and transfer LPG from the leaking section to the next section after which the leaking section can be isolated quickly. The LPG multiphase transfer pump has provisions to pump the multiphase LPG to the next section across the pipeline with a provision to simultaneously load tank vehicles through a discharge manifold.
The apparatus 100 for evacuating LPG from an LPG cross-country pipeline during an emergency like a pipeline rupture or a leak, of the present disclosure, is depicted in Figure 1. In accordance with the present disclosure, the apparatus 100 comprises:
1. An emergency response vehicle (ERV), i.e., vehicle 102
2. A multiphase pump 104 mounted on a skid
3. A hydraulic motor 110
4. A power transfer module (PTO) unit 103
5. A lubrication oil system (not shown)
6. A nitrogen purging system (not shown)
7. A hydraulic reservoir 112
8. A suction hose 106 and a delivery hose 108
9. Strainer (not shown)
10. Multi-Phase flowmeter 120
11. A pump control panel 114
12. A jib crane 116
13. Globe valves, check valves and a shut-off valve (not shown)
14. Instrumentation skid and PLC system 118
15. Pump Mechanical Seal (not shown)
The LPG evacuation system is installed on the trailer portion of the vehicle 102, as illustrated in Figure 1. In an exemplary embodiment, the engine of the vehicle 102 is of 456 kW @ 1500 rpm, the input power capacity of the power transfer module 103 is of 456 kW @ 1500 rpm and the output power capacity of the power transfer module 103 is of 432 kW @ 1500 rpm, the hydraulic motor 110 is of around 324 kW @ 3600 rpm and the hydraulic multiphase pump is of around 324 kW maximum power @ 3280 rpm. A hydraulic pump of 410 kW @ 1500 rpm is also provided in the hydraulic system.
In a preferred embodiment, the vehicle 102 is configured with a flame-proof alternator for charging electrical storage batteries installed thereon. Moreover, the vehicle 10 is provided with an exhaust spark arrestor.
Preferably, the hydraulic fluid should be fire-resistant.
The multiphase pump 104 is operable with a gas volume fraction (i.e., the ratio of the gas volumetric flow rate to the total volumetric flow rate of fluid) of 50% or above, at a flow rate around 200 m3/hr and a pressure head of around 350m (i.e., 22 bar above atmospheric pressure).
The skid of the multiphase pump 104 is preferably provided with instrumentation suitable for multiphase application. The pump 104 shall be equipped with double mechanical seal as per API Plan 53B. The PLC system 118 is shock/vibration resistant. Machine safeguarding instrumentation, including vibration sensors, temperature sensors, speed sensors, pressure transmitters and so on, are also provided. A centralized PLC system 118, installed in a self-contained flameproof panel, with panel-mounted HMI (human-machine interface) is provided for auto/manual PID control and also for taking care of interlocks. The suction and the discharge ports of multiphase pump 20 are provided with compact 24 V DC electric actuators which are supported by an additional battery bank of the vehicle 10 for their actuation. Bypass flow control valve (FCV) / automatic recirculation valve (ARV) / pressure relief valve (PRV) can be provided as per the process requirement. A multiphase flow meter (MPFM) 70 is provided on the suction side of multiphase pump 104, which can be interfaced with a programmable logic control (PLC) system 118 for automatic PID control.
For ensuring fire and gas safety, at least two infrared (IR) point-type gas detectors can be provided to be interfaced with the PLC system. The purging system with a bank of nitrogen cylinders is provided for carrying out purging of the multiphase pump 20. The capacity of the cylinder banks is preferably 2-3 times of the total volume of the hoses/piping/pump. Furthermore, a sprinkler piping system can be installed so that water for extinguishing fire can be supplied in case of an exigency. Preferably, the sprinkler piping system is a medium velocity water spray system. Two 9 kg dry chemical powder (DCP) fire extinguishers and a 75 kg DCP fire extinguisher are also provided. An earthing grid with mobile earthing electrodes can also be provided.
For handling for installation and removal of the suction and the discharge hoses of the multiphase pump 104, a telescopic jib crane 116 is installed on the vehicle 102. In an embodiment, the vehicle 102 is provided with a closed-loop variable displacement pump.
Additionally, a cooling arrangement for the system is required. The cooling arrangement comprises of a cooler for the power transfer module 103, a cooler for the thrust bearing of the multiphase pump 104, a cooler for the double mechanical seals, a cooler for the main hydraulic system and a cooler for an auxiliary hydraulic system (if required). The cooling arrangement can be a common combination cooler (not shown) with multiple segregated circuits with a hydro-motor-driven cooler fan with required automation to optimize the utilization of the available space. The entire equipment shall be installed on antivibration mounts to avoid shocks or vibration while the vehicle is traversing and also during operation.
In another embodiment, the type of the vehicle 102 is road transport vehicle.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a method and a apparatus, which:
• Ensures quick evacuation of LPG from a pipeline during an emergency thereby ensuring that LPG leak can be arrested;
• Recovers LPG which would otherwise had to be vented into atmosphere; and
• Obviates the release of the LPG into the environment, thereby preventing major accident.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A method for evacuating LPG from a leaking section of a pipeline in response to leaking of LPG from said leaking section, said method comprising:
• isolating said leaking section of said pipeline by closing a valve immediately downstream of said section and a valve immediately upstream of said section;
• transporting a pump 104, a suction hose 106 and a delivery hose 108 to a sectionalizing valve (not shown in figure) of said leaking section by a vehicle 102, said sectionalizing valve being located near to said leaking section;
• clamping said suction hose 106 to suction of said sectionalizing valve and clamping said delivery hose 108 to an LPG storage or to the next section of the pipeline in a leakproof manner;
• priming and inertization with Nitrogen of said pump to ensure absence of air; and
• pumping under suction, LPG from said leaking section by said pump 104 into said LPG storage or to the next section of the pipeline.
2. The method as claimed in claim 1, wherein said pump 104 is driven by the engine of said vehicle 102.
3. The method as claimed in claim 1, wherein said pump 104 is configured to handle LPG in liquid,vapour or fluid state.
4. The method as claimed in claim 1, wherein said method includes dampening of vibrations incident from said pumping unit by anti-vibration mounts provided on said skid of said vehicle 102.
5. The method as claimed in claim 1, wherein said method includes measuring of flow of LPG fluid through said pumping unit by a multiphase flowmeter 120.
6. The method as claimed in claim 1, wherein said method includes detecting fire or gas is provided with fire and gas detectors.
7. An apparatus 100 for evacuating LPG from a leaking section of a pipeline in response to leaking of LPG from said leaking section, said apparatus comprising:
• a vehicle 102 configured adapted to be located in the vicinity of leaking section;
• a pump 104 mounted on said vehicle 102;
• a suction hose 106 configured to be detachably attached between the leaking section and said pump 104; and
• a delivery hose 108 configured to be detachably attached between said pump 104 and an LPG storage.
8. The apparatus 100 as claimed in claim 7, wherein said apparatus 100 includes a power transfer module 103 for transferring from the engine of said vehicle to said pump 104.
9. The apparatus 100 as claimed in claim 10, wherein said pump 104 is configured to handle LPG in liquid, vapour or fluid state.
10. The apparatus 100 as claimed in claim 10, wherein said suction hose 106 and said delivery hose 108 are flexible.
11. The apparatus 100 as claimed in claim 10, wherein anti-vibration mounts are provided under a skid for dampening vibrations incident from said apparatus 100, said skid mounted on said vehicle 102.
12. The apparatus 100 as claimed in claim 10, wherein a multiphase flowmeter 120 is provided on said apparatus for measurement of LPG flow.
13. The apparatus 100 as claimed in claim 10, wherein a telescopic jib crane 116 is mounted on said apparatus for handling said suction hose 106 and said delivery hose 108.
14. The apparatus 100 as claimed in claim 10, wherein said apparatus 100 includes a hydraulic motor 110, a hydraulic reservoir 112, a cooler and a closed-loop variable displacement pump.
15. The apparatus 100 as claimed in claim 10, wherein said apparatus 100 is provided with fire and gas detectors.
16. The apparatus 100 as claimed in claim 10, wherein said LPG storage is a mobile storage such as a vehicle.
17. The apparatus 100 as claimed in claim 10, wherein said LPG storage is a storage configured to be in fluid communication with said pipeline.
18. The apparatus 100 as claimed in claim 20, wherein said vehicle 102 is a road transport vehicle.