Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B67—OPENING, CLOSING OR CLEANING BOTTLES, JARS OR SIMILAR CONTAINERS; LIQUID HANDLING
  • B67D—DISPENSING, DELIVERING OR TRANSFERRING LIQUIDS, NOT OTHERWISE PROVIDED FOR
  • B67D7/00—Apparatus or devices for transferring liquids from bulk storage containers or reservoirs into vehicles or into portable containers, e.g. for retail sale purposes
  • B67D7/06—Details or accessories
  • B67D7/76—Arrangements of devices for purifying liquids to be transferred, e.g. of filters, of air or water separators
  • B67D7/763—Arrangements of devices for purifying liquids to be transferred, e.g. of filters, of air or water separators of air separators

Definitions

• the present invention relates to a degassing system for a hydrocarbon distributor.
• a hydrocarbon dispenser comprising means for controlling the gas content of the hydrocarbon.
• the hydrocarbon distributor is provided with a vortex type degasser which is associated with detection means making it possible to interrupt the distribution of hydrocarbons as soon as the gas content in the latter is greater than a predetermined value.
• Vortex degassers are commonly used in this type of installation. They consist in creating a helical circulation of the mixture of liquid and gas in an elongated cylindrical enclosure, in collecting the fraction enriched in liquid by a lateral tube and in taking the fraction enriched in gas by an axial tube.
• Figure 1 attached schematically illustrates the degassing device commonly used in hydrocarbon distributors.
• the pump 12 which passes the hydrocarbon from its storage tank 14 to the vortex degasser 16 which is constituted by an elongated cylindrical enclosure as already indicated.
• the hydrocarbon possibly charged with gas is introduced at a first end of the enclosure 16 by the line 18 so that a helical movement of the hydrocarbon is created in the enclosure 16.
• the lateral line 22 it is withdraws the degassed hydrocarbon and via the axial pipe 20 the fraction of the liquid possibly enriched in gas is removed.
• the sampling tube 20 is connected with a pipe 26 which is itself connected to a degassing tank or degassing tank 24.
• this known degassing system has a relatively long response time since when the liquid / gas mixture becomes enriched with liquid, it is necessary to unnecessarily pour enough liquid into the degassing tank to raise the level of liquid so to make the valve travel its entire stroke between its open position and its closed position.
• the invention proposes a degassing system for a hydrocarbon distributor comprising a pump for circulating the hydrocarbon, comprising a degassing assembly having an inlet connected to the outlet of the pump. , a degassed hydrocarbon outlet and an outlet for withdrawing the hydrocarbon / gas mixture, a degassing tank and means forming a pipe for connecting said sampling outlet to said degassing tank, the end of said means forming a pipe opening into said tank degassing presenting an adjustable effective passage section, remarkable in that it further comprises pressure means for modifying said effective passage section as a function of the gas content of the hydrocarbon in the degassing assembly.
• valve control is carried out a posteriori and downstream since it is necessary that liquid flows into the degassing tank for the valve to close, whereas in the invention the control pressure means is a priori and upstream, the degassing system being immediately effective.
• said means forming a pipe comprise a single pipe, and in that said pressure means comprise, at the end of the pipe opening into said degassing tank, means forming a venturi provided with a neck, said neck being immersed in the hydrocarbon contained in said degassing tank, the outlet of said venturi being disposed above the level of the hydrocarbon and being provided with a restriction, said neck of means forming venturi being provided with an opening opening into the hydrocarbon of said degassing tank, whereby when the gas content of the hydrocarbon leaving through said pipe is large, part of the flow of the mixture also leaves through said opening.
• said pipe-forming means comprise a first and a second pipe, in that the open end of the first pipe opens into said degassing tank, and in that said pressure means comprise a shutter through which said second pipe opens into said degassing tank and means for controlling the closing of said shutter when the gas content in the hydrocarbon is less than a predetermined value.
• said pipe-forming means comprise a first pipe, a first end of which is connected to said sampling outlet and the other end of which is connected to venturi means having a neck and a outlet fitted with a restriction arranged above the level of the hydrocarbon in said degassing tank, a second pipe, one end of which is connected to the sampling outlet and the other end of which opens into said degassing tank above the free level of hydrocarbon, and in that said pressure means comprise a movable shutter of said pipe and control means of said shutter so that the shutter is open when the pressure at the neck of the venturi means is high and that said shutter is closed otherwise.
• FIG. 2a shows in vertical section a first embodiment of the degassing system
• FIG. 2b, 2c and 2d are detail views showing different embodiments of the venturi means
• FIG. 3 shows a second embodiment of the degassing system
• FIG. 4 shows a third embodiment of the degassing system
• - Figure 5 shows in vertical section a fourth embodiment of the degassing system
• - Figure 6 shows a fifth embodiment of the degassing system
• - Figure 7a is a vertical sectional view of the assembly of a sixth embodiment of the degassing system.
• Figure 7b is a detail view of Figure 7a.
• FIG. 2a we will describe a first embodiment of the degassing system.
• the pump 12 with its non-return valve 30 and its filter 31 which circulates the hydrocarbon arriving through line 32 of the storage tank.
• the outlet 33 of the pump is connected to the vortex degassing enclosure 16 of which the axial sampling pipe 20 and the outlet pipe 22 of the degassed hydrocarbon have been shown.
• a recycling circuit 34 provided with the valve 36 which makes it possible to reintroduce at the inlet of the pump the excess flow of hydrocarbon.
• the degassing tank 24 which comprises a valve 37 allowing the recycling of the hydrocarbon at the inlet of the pump after its degassing in the degassing tank 24.
• This structure is well known in distributors of hydrocarbons to allow degassing of the hydrocarbon delivered.
• the sampling pipe 20 is connected to a pipe 38 which opens into the degassing tank 24. More specifically, the end 38a of the pipe 38 is connected to a venturi device 40, this venturi device comprising a neck 42 and an outlet 44 opening above the free level of the hydrocarbon in the tank 24. This outlet 44 is preferably provided with a flow restriction 46.
• the neck 42 of the venturi 40 is provided with an opening 48 which is arranged below the regulated free level of the hydrocarbon in the tank 24.
• the opening 48 provided in the neck 42 of the venturi allows, according to the invention, to modify the effective passage section of the gas / liquid mixture flowing in line 38 as a function of the gas content.
• the operation of the venturi 40 with its orifice 48 is as follows.
• a venturi or herschel type nozzle is capable creating a strong depression at the neck when the latter is traversed by a flow of fluid Q v pure liquid supplied by the upstream pressure P and opening at atmospheric pressure P 0 .
• the absolute pressure at the neck can be close to zero, limited only by the vapor pressure of the fluid. This pressure p at the neck can still remain very low even if a restriction 46 is placed downstream of the depressor: the orifice 48 formed at the neck then makes it possible to draw liquid into the tank.
• This flow of aspirated liquid q v then mixes with the flow Q v supplied by the pressure P and a flow q v + Qv leaves towards atmospheric pressure.
• the pressure drop on restriction 46 increases, going from a value proportional to Q v 2 to a value proportional to (Q v + qv) 2 which has the effect of slowing the flow rate Q v for the same pressure P It is no longer the same when gas is mixed in the fluid flow Q v passing through the nozzle.
• the relative pressure p at the throat of the nozzle increases rapidly until it becomes strongly positive and passes above atmospheric pressure P 0 : the flow q v is reversed and the fluid containing air is evacuated at the neck.
• the degassing can then be carried out not only downstream of the nozzle but also through the lateral opening at the neck 48, appreciably increasing the evacuation efficiency.
• the effective outlet section is reduced when the gas content is zero or very low. As the gas content increases, the effective cross-section also increases.
• the operation of the degassing installation shown in FIG. 2a is as follows: in the absence of air in the hydrocarbon, a flow rate Q v exits through the pipe 38 and passes through the venturi 40 to go towards the tank degassing. In the absence of gas, the depression formed at the neck of the venturi causes the suction of a flow of liquid q v , the mixture Q v + qv being expelled towards the degassing tank through the restriction 46.
• the effective flow which ends up in the degassing tank is limited to Q v since the flow q v only circulates locally by entering and then leaving the nozzle. This nozzle acts as a circulation pump for the flow q v and must therefore provide work. Its internal resistance increases and its feed rate Qv is reduced.
• FIG. 2b shows in more detail a form of venturi 40 of conventional type which , according to the invention, is provided with the orifice 48.
• FIG. 2c a venturi device of the Golaz nozzle / tube type has been represented with an annular vacuum chamber 50 into which opens the orifice 48 ′ which is the equivalent of the orifice 48.
• This arrangement is strictly equivalent to that of Figure 2b.
• FIG. 2d another equivalent of the venturi device has been shown, which is constituted by a nozzle 52 of the injector type similar to that used to mix the gases intended to supply the burners.
• the annular opening 54 plays exactly the same role as the orifice 48 or the orifice 48 '.
• venturi device is meant not only the venturi proper of Figure 2b but also the nozzle devices shown in Figures 2c and 2d.
• the axial sampling tube 20 is always connected to a tube 38 provided at its end with a venturi device 40, the neck 42 of the venturi device being provided with an orifice 48.
• the axial sampling tube 20 is also connected to a second pipe 60, the outlet 62 of which opens into the degassing tank 24 can be closed off by a movable valve system 64 controlled by a deformable membrane 66.
• the control chamber 68 of the valve limited by the deformable membrane 66 is directly connected to the opening 48 provided in the neck 42 of the venturi 40.
• the operation of this embodiment is as follows.
• the outlet 44 of the venturi 40 is provided with a restriction 46 which makes it possible to limit the flow rate flowing through the venturi to a low value of the order of 1 to 2 liters per minute for example. If the flow rate Q v flowing through the line 38 is devoid of gas, the neck 42 of the venturi is in depression and the deformable membrane 66 is maintained in a position such that the movable shutter 64 is closed. Line 60 is therefore inactive.
• FIG. 4 we will describe a third embodiment of the degassing device.
• This embodiment is based on the observation that the presence of air or gas in the hydrocarbon drawn in by the pump generally leads to a reduction in the distribution pressure, which in the alternative decreases the degassing capacities.
• This embodiment takes advantage of this reduction in the pressure of the hydrocarbon when it contains air.
• the second pipe 60 also connects the sampling tube 20 to a chamber 72 provided with a ball valve constituted by the ball 74, the seat 76 and the return spring 78 which tends to separate the ball from its seat.
• the pressurization of the installation causes a jet Q ′ v in the line 60 which presses the ball 74 on its seat 76 by compressing the spring 78.
• the flow in the line 60 is therefore interrupted. If as a result of a strong gas suction, the pressure drops, and in particular the pressure in the pipe 60, below a certain value, the spring 76 moves the ball away from its seat allowing the installation of a flow permanent degassing in line 60 which is added to the flow rate in line 38.
• the degassing by the vortex degasser 16 is thus significantly improved.
• Another method intended to increase the efficiency of degassing is set out in FIG. 5.
• This constant flow Q of the pump 12 is ensured at all times by regulating the return valve 36.
• This variation in ⁇ p developed at two pressure taps located on either side of the inlet 33 of the vortex tube 16, for example, is directed by two conduits 80 and 82 towards a membrane sensor 84 carrying a valve. valve 86.
• This valve 86 can modify the effective section of the auxiliary degassing channel 60 ′ by which a flow Q ′ v can be added to the permanent flow Q v which flows through the main channel 38 provided at its end 14 d 'a restriction 70 which strongly limits Q v .
• Figures 6 and 7a illustrate two embodiments of the degassing system based on this principle.
• the axial sampling pipe 20 is connected on the one hand to the pipe 38 provided with its restriction 70 and on the other hand to the auxiliary pipe 60 whose end 60a is provided with a valve 92 controlled by the displacements of a deformable membrane 94.
• the position of the membrane 94 and therefore the state of the valve 92 are controlled by the pressure prevailing in a control chamber 96.
• a pipe 98 allows a permanent flow towards the degassing tank 24.
• the end 98a of the pipe 98 is disposed above the free level of the hydrocarbon in the tank 24 and is directed upwards to form a fluid jet 100. This jet 100 is directed to a recovery nozzle 102 connected to the control chamber 96.
• the pipe 38 connected to the axial sampling pipe 20 of the vortex degasser 16 comprises a branch pipe 60 "of small section whose end 60" has an outlet in the degassing tank 24.
• the end 38a of the pipe 38 is connected to a slide valve 1 10.
• the valve 1 10 has an outlet 1 12 disposed in the tank 24 above the free level of the hydrocarbon in the tank.
• the drawer 1 14 of the valve 1 10 is controlled by a pressure applied to its end face 1 14a, its other end face 1 14b being subjected to the action of a return spring 1 16.
• a pipe 118 ensures permanent communication between the zone 90 of the outlet 22, 34 of the degasser 16 with the control chamber 120 of the slide valve 1 10 defined by the end 1 14a of the drawer.
• the pressure prevailing in the zone 90 is permanently applied to the end face 1 14a of the valve spool.
• the drawer 1 14 When the pressure is high in the zone 90, the drawer 1 14 is pushed back by compressing the spring 1 16. In this position, the drawer 1 14 interrupts the communication between the inlet 38a and the outlet 1 12 of the valve. Only the pipe 60 "allows the liquid to exit to the tank 24. On the contrary, when the pressure in the zone 90 is lower, the slide 1 14 occupies the position shown in FIG. 7a and the liquid / gas mixture can also exit through the valve 1 10, which of course increases the effective degassing section.
• FIG. 7b illustrates a preferred embodiment of part of the device shown schematically in Figure 7a.
• the valve 1 10 is constituted by a body 120 having an inlet opening 122 connected to the end 38a of the pipe 38 and an outlet opening 124.
• the drawer 1 14 has an annular light 126 allowing for certain positions of the drawer communicate entry and exit.
• An orifice 128 opening directly into the tank 24 constitutes the equivalent of the pipe 60 ".
• a return spring 130 which acts on a shoulder 132 of the drawer.
• the control chamber 134 of the valve is directly connected to the zone 90 by a screw 136 having a hole 138, 140. This screw 136 constitutes the equivalent of the pipe 1 18 of FIG. 7a.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Degasification And Air Bubble Elimination (AREA)
• Feeding And Controlling Fuel (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Sampling And Sample Adjustment (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Applications Claiming Priority (3)

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• 1995
  • 1995-02-15 FR FR9501715A patent/FR2730484B1/fr not_active Expired - Lifetime
• 1996
  • 1996-02-13 ES ES96904133T patent/ES2150659T3/es not_active Expired - Lifetime
  • 1996-02-13 EP EP96904133A patent/EP0809604B1/de not_active Expired - Lifetime
  • 1996-02-13 US US08/894,349 patent/US5902382A/en not_active Expired - Lifetime
  • 1996-02-13 WO PCT/FR1996/000235 patent/WO1996025358A1/fr active IP Right Grant
  • 1996-02-13 DE DE69609311T patent/DE69609311T2/de not_active Expired - Lifetime
  • 1996-02-13 AT AT96904133T patent/ATE194589T1/de active

Non-Patent Citations (1)

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