CN102261559A - Cooling system and method for low-temperature liquid hydrocarbon storage tank - Google Patents
Cooling system and method for low-temperature liquid hydrocarbon storage tank Download PDFInfo
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Abstract
The invention relates to a cooling system and method for a low-temperature liquid hydrocarbon storage tank. The cooling system comprises a liquid hydrocarbon transportation ship, a ship unloading arm, a liquid hydrocarbon output general pipe, a cooling straight pipe and a cooling annular pipe, wherein the liquid hydrocarbon transportation ship carries liquid hydrocarbon; the ship unloading arm is connected with a liquid hydrocarbon output pipe of the liquid hydrocarbon transportation ship; the liquid hydrocarbon output general pipe is connected with an output end of the ship unloading arm to output the liquid hydrocarbon; the cooling straight pipe is connected with the liquid hydrocarbon output general pipe and enters the inside of an inner tank via an arc crown of an outer tank, an insulation material and a suspended ceiling of the inner tank sequentially; the cooling annular pipe is positioned in a horizontal plane in the inner tank, and comprises an edge annular pipe and a liquid hydrocarbon dispersion pipe, wherein the liquid hydrocarbon dispersion pipe penetrates the central point of the edge annular pipe and is used for dispersing liquid hydrocarbon; the edge annular pipe is communicated with the liquid hydrocarbon dispersion pipe, and the liquid hydrocarbon dispersion pipe is communicated with the cooling straight pipe at the central point of the edge annular pipe; and openings are uniformly distributed at the lower part of the edge annular pipe at intervals, and each opening is connected with a hollow nozzle used for spraying and atomizing outflowing liquid hydrocarbon. The cooling system and method provided by the invention enables the cooling speed of the storage tank to be uniform.
Description
Technical Field
The invention relates to the field of low-temperature liquid hydrocarbon storage and transportation, in particular to a cooling system and a cooling method for a low-temperature liquid hydrocarbon storage tank.
Background
The low-temperature liquid hydrocarbon is usually hydrocarbon substances with low boiling point under the standard atmospheric pressure, can be changed into liquid only under the conditions of pressurization and temperature reduction, and the volume of the liquefied hydrocarbon is reduced by hundreds of times, so that the low-temperature liquid hydrocarbon is very favorable for long-distance transportation. Which include Liquefied Natural Gas (LNG), Liquefied Ethylene Gas (LEG), liquid ethane, liquid propylene, propane, and the like.
Because the demand of China for low-temperature liquid hydrocarbon is huge at present, and the production of domestic low-temperature liquid hydrocarbon cannot meet the demand, a large amount of imports are needed. As shown in fig. 1, in the prior art, a cryogenic liquid hydrocarbon transport ship 108 is used to transport cryogenic liquid hydrocarbon back to the country, an unloading arm 109 provided on the shore is connected to a cryogenic liquid hydrocarbon output pipe of the cryogenic liquid hydrocarbon transport ship 108, and a cryogenic liquid hydrocarbon output main pipe 110 is connected to an output end of the unloading arm 109, so that cryogenic liquid hydrocarbon loaded on the cryogenic liquid hydrocarbon transport ship 108 can reach the shore along the cryogenic liquid hydrocarbon output pipe, the unloading arm 109, and the cryogenic liquid hydrocarbon output main pipe 110, and further enter the cryogenic liquid hydrocarbon storage tank along a cryogenic liquid hydrocarbon input pipe 112 connected to the cryogenic liquid hydrocarbon output main pipe 110 for storage under the condition that a cryogenic liquid hydrocarbon input switch valve 114 shown in fig. 1 is in an open state. The low-temperature liquid hydrocarbon storage tank in the prior art comprises an outer tank 102, an inner tank 101 and an insulating material 104 filled between the inner tank 101 and the outer tank 102, wherein the inner tank 101 is provided with a suspended ceiling 103 connected with the vault of the outer tank 102 through a suspension rod 105, as shown in fig. 1, a drainage pipe 116 is further arranged inside the inner tank 101 and right below the outlet of a low-temperature liquid hydrocarbon input pipe 112 so as to drain the input low-temperature liquid hydrocarbon and realize bottom discharge.
After the cryogenic liquid hydrocarbon storage tank is constructed, before cryogenic liquid hydrocarbon is input into the cryogenic liquid hydrocarbon storage tank, drying, degeneration and cooling work are required to be performed. As shown in fig. 1, the drying and degeneration operations may be performed by passing through the dome of the outer tank 102 into the nitrogen purge pipe 106 between the inner tank 101 and the outer tank 102, and in a state where the nitrogen purge switching valve 107 is opened, nitrogen enters the space between the inner tank 101 and the outer tank 102 along the nitrogen purge pipe 106, thereby discharging air (including oxygen, water vapor, etc.) in the space, and implementing replacement of air by nitrogen, which may prevent the heat insulating material 104 from losing heat insulating properties due to the condensation of water vapor, and may prevent combustible gaseous hydrocarbons (generated by gasification of low-temperature liquid hydrocarbons) that may be leaked from the inner tank 101 from being burnt and exploded when encountering oxygen. Of course, it is also possible to provide a nitrogen substitution pipe which sequentially penetrates the dome of the outer tank 102, the insulation material 104, and the ceiling 103 of the inner tank 101 into the inside of the inner tank 101 to supply nitrogen to the inside of the inner tank 101, and to provide a nitrogen substitution switching valve thereon to control the introduction of nitrogen. When the nitrogen replacement switch valve is in an open state, nitrogen can enter the inner tank 101 along the nitrogen replacement pipe to replace air in the inner space of the inner tank, and the safety of the low-temperature liquid hydrocarbon storage tank is ensured.
The cooling of the low-temperature liquid hydrocarbon storage tank is a complicated task, for example, if the cooling speed is too high, the steel plates used for manufacturing the inner tank 101 and the outer tank 102 have a large temperature difference, generate a high stress, and possibly cause internal cracking, thereby causing leakage of the low-temperature liquid hydrocarbon. Therefore, the cooling rate of any point in the inner tank 101 cannot be too fast, and should be kept within 3 ℃/hour, and cannot exceed 5 ℃/hour at the fastest, and the temperature difference between any two points does not exceed 30 ℃.
The prior art cooling of cryogenic liquid hydrocarbon storage tanks is accomplished using cryogenic liquid hydrocarbons carried by cryogenic liquid hydrocarbon carrier 108. The low-temperature liquid hydrocarbon entering the low-temperature liquid hydrocarbon output header pipe 110 flows out from an opening formed in the bottom of the cooling loop pipe 115 through the cooling straight pipe 111 connected with the low-temperature liquid hydrocarbon output header pipe 110 and the cooling loop pipe 115 in the horizontal plane communicated with the tail end of the cooling straight pipe 111, and then enters the inner tank 101, and the low-temperature liquid hydrocarbon flow regulating valve 113 with a controllable switching state is further arranged on the cooling straight pipe 111 to regulate the input speed of the low-temperature liquid hydrocarbon, so that the cooling speed is controlled. Fig. 2 is a prior art configuration of a cooling loop provided from a bottom elevation view of the cooling loop. As shown in FIG. 2, the communication between the straight cooling tubes 111 and the cooling loop 115 is at the edge of the cooling loop 115 where the low temperature liquid hydrocarbon flowing along the straight cooling tubes 111 splits into two paths entering both sides of the cooling loop 115. The bottom of cooling loop 115 is uniformly provided with a plurality of openings (as indicated at 201, 202 and 204) to allow the flow of cryogenic liquid hydrocarbon to flow vertically downward through the openings. As can be seen, in the prior art, since the distances between the communication positions of the cooling loop pipe 115 and the cooling straight pipe 111 and the different openings are different (as shown in fig. 2, the distances between the communication positions and the openings 201, 202, and 204 are sequentially increased), the flow rates of the low-temperature liquid hydrocarbons flowing out from the different openings are different (the flow rates of the low-temperature liquid hydrocarbons flowing out from the openings 201, 202, and 204 are sequentially decreased). In addition, since each opening is disposed at a position such that the flow direction of the low-temperature liquid hydrocarbon flowing out of the opening is directed vertically downward, the portion of the inner tank 101 within the area covered by the opening of the cooling loop 115 is subjected to temperature drop (cooling) due to direct or indirect contact with the low-temperature liquid hydrocarbon, and the portion not within the area covered by the opening (such as the tank wall, the bottom edge of the tank, etc.) is not subjected to temperature drop (cooling). Both of the above problems cause non-uniform cooling rate at each point inside the inner tank, and it is inevitable to reduce the input rate of the low-temperature liquid hydrocarbon as much as possible to maintain the cooling rate of the inner tank within 3 c/hour and the temperature difference between any two points not exceeding 30 c, which results in a very long cooling time of the low-temperature liquid hydrocarbon storage tank.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a cooling system and a cooling method for a low-temperature liquid hydrocarbon storage tank, which can ensure that the cooling speed of each point in the inner tank is uniform.
The technical scheme for solving the technical problems is as follows: a cooling system for a cryogenic liquid hydrocarbon storage tank, the cryogenic liquid hydrocarbon storage tank comprising: the inner tank is positioned inside the outer tank; the suspended ceiling of the inner tank is connected with the vault of the outer tank through a suspension rod; a heat insulating material is filled between the inner surface of the outer tank and the outer surface of the inner tank; a nitrogen purging pipe penetrates through the vault of the outer tank to enter a space between the inside of the outer tank and the outside of the inner tank, and a nitrogen purging switch valve is installed on the nitrogen purging pipe; an emptying pipeline with one end communicated with the atmosphere and the other end communicated with the gas phase space inside the outer tank by penetrating through the vault of the outer tank; the opening degree of the emptying valve is adjustable and is positioned on the emptying pipeline; the system comprises: a cryogenic liquid hydrocarbon carrier vessel for loading the cryogenic liquid hydrocarbon; a ship unloading arm connected with the low-temperature liquid hydrocarbon output pipe of the low-temperature liquid hydrocarbon transport ship; a low-temperature liquid hydrocarbon output main pipe connected with the output end of the ship unloading arm to output the low-temperature liquid hydrocarbon; the cooling straight pipe is connected with the low-temperature liquid hydrocarbon output main pipe, sequentially penetrates through the vault of the outer tank, the heat insulating material and the suspended ceiling of the inner tank, and enters the inner tank; the cooling ring pipe is positioned in a horizontal plane in the inner tank;
the cooling ring pipe comprises an edge ring pipe and a low-temperature liquid hydrocarbon dispersion pipe which penetrates through the center point of the edge ring pipe and has a dispersion effect on low-temperature liquid hydrocarbon; the edge ring pipe is communicated with the low-temperature liquid hydrocarbon dispersion pipe, and the low-temperature liquid hydrocarbon dispersion pipe is communicated with the cooling straight pipe at the central point of the edge ring pipe;
the lower part of the edge ring pipe is provided with openings which are uniformly distributed at intervals, and each opening is connected with a hollow nozzle which has the functions of spraying and atomizing the flowing low-temperature liquid hydrocarbon.
On the basis of the technical scheme, the invention can be further improved as follows:
further, two adjacent openings are staggered close to the central point of the edge ring pipe and far away from the central point of the edge ring pipe.
Further, the nozzle is provided with a central axis, and an included angle between the downward direction and the vertical downward direction of the central axis is a downward deflection angle of the central axis of the nozzle; then
The central axis of a nozzle connected with an opening far away from the central point of the edge ring pipe is downwards far away from the vertical line of the central point, and the downward deflection angle of the central axis of the nozzle is between 30 and 60 degrees;
the central axis of the nozzle connected to the opening near the center point of the edge collar is directed downwards towards the vertical line of the center point, and the downward deflection angle of the central axis of the nozzle is between 30 and 60 degrees.
Further, the nozzle comprises a butt joint opening part, a connecting part and a low-temperature liquid hydrocarbon spraying and atomizing part which are connected in sequence; wherein,
the butt joint opening part is a hollow pipeline which is connected to an opening on the edge ring pipe and communicated with the inside of the edge ring pipe;
the connecting part is a hollow pipeline communicated with the butt joint opening part;
the low-temperature liquid hydrocarbon spraying and atomizing part is a spiral cone with gradually reduced spiral radius.
Further, the device also comprises a low-temperature liquid hydrocarbon flow regulating valve with controllable opening degree and a flow meter capable of indicating flow, wherein the low-temperature liquid hydrocarbon flow regulating valve is positioned on the cooling straight pipe.
And the low-temperature liquid hydrocarbon input pipe is connected with the low-temperature liquid hydrocarbon output main pipe, sequentially penetrates through the vault of the outer tank, the heat insulating material and the suspended ceiling of the inner tank, and enters the inner tank.
Further, a draft tube is included inside the inner vessel with an open inlet opposite the output end of the cryogenic liquid hydrocarbon input tube.
Further, the device also comprises a low-temperature liquid hydrocarbon input switch valve which is positioned on the low-temperature liquid hydrocarbon input pipe and can be controlled in switch state.
And further, the system also comprises a gaseous hydrocarbon output pipe, wherein one end of the gaseous hydrocarbon output pipe is communicated with the gas phase space on the low-temperature liquid hydrocarbon transport ship, and the other end of the gaseous hydrocarbon output pipe sequentially penetrates through the vault of the outer tank, the heat insulation material and the ceiling of the inner tank, enters the inner tank and is communicated with the gas phase space in the inner tank.
Further, the device also comprises a gaseous hydrocarbon output switch valve which is arranged on the gaseous hydrocarbon output pipe and can be controlled in a switch state.
Further, the inner tank is a hollow cylindrical flat-bottomed cup-shaped container, and the suspended ceiling of the inner tank is circular;
temperature sensors are uniformly distributed on more than one concentric circle which takes the circle center as the circle center on the inner bottom surface of the inner tank;
temperature sensors are distributed at different heights on the inner side wall of the inner tank;
temperature sensors are uniformly distributed on more than one concentric circle which takes the circle center as the circle center on the upper bottom surface of the suspended ceiling;
temperature sensor on the interior bottom surface of inner tank and the inside wall, temperature sensor on the last bottom surface of furred ceiling all links to each other with temperature indicator.
And furthermore, the temperature indicating alarm is connected with the temperature sensors on the inner bottom surface and the inner side wall of the inner tank and the temperature sensors on the upper bottom surface of the suspended ceiling.
Further, the air pressure indicating alarm device is used for detecting and indicating the air pressure in the inner tank and giving an alarm when the air pressure exceeds the standard.
The gas outlet pipe is communicated with the gas phase space in the inner tank and sequentially penetrates through the suspended ceiling of the inner tank, the heat insulating material and the vault of the outer tank to be connected with a torch system; and a safety valve with certain take-off pressure is arranged on the gas output pipe.
Further, the device also comprises a nitrogen concentration sampling detector for detecting the nitrogen concentration in the inner tank.
In addition, the present invention provides a cooling method of a low temperature liquid hydrocarbon storage tank based on the cooling system of a low temperature liquid hydrocarbon storage tank according to claim 1; the system is characterized in that a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe, a cooling straight pipe and a cooling ring pipe of the low-temperature liquid hydrocarbon transport ship form a cooling pipeline; the method comprises the following steps:
step 1: the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship reaches the nozzle along the cooling pipeline, and the outflowing low-temperature liquid hydrocarbon is sprayed and atomized by the nozzle to diffuse into the inner tank;
step 2: judging whether the temperature drop temperature difference condition is satisfied, if not, stopping the low-temperature liquid hydrocarbon from entering the inner tank along the cooling pipeline until the temperature drop temperature difference condition is satisfied; wherein the temperature drop difference condition comprises: the temperature drop speed of any point on the inner bottom surface and the inner side wall of the inner tank and the upper bottom surface of the suspended ceiling is not more than 3 ℃/hour, and the temperature difference between any two points is not more than 30 ℃;
and step 3: judging whether the temperature of any point on the inner bottom surface of the inner tank is not higher than a set temperature, if so, executing the step 4, otherwise, executing the step 1;
and 4, step 4: and continuing to make the low-temperature liquid hydrocarbon reach the nozzle along the cooling pipeline and enter the inner tank under the spraying and atomizing of the nozzle until the height of the low-temperature liquid hydrocarbon in the inner tank reaches a height set value, and finishing the cooling.
Further, before the step 1, the method further comprises:
step 01-1: opening the nitrogen purging switch valve to allow nitrogen to enter a space between the inside of the outer tank and the outside of the inner tank through the nitrogen purging pipe to replace air in the space; simultaneously opening a vent valve on the vent pipeline to discharge the replaced air to the external atmosphere;
step 02-1: and under the condition that the oxygen and water vapor contents of the space between the inside of the outer tank and the outside of the inner tank meet the specification requirement and the nitrogen pressure is greater than the atmospheric pressure outside the outer tank, closing the nitrogen purging switch valve and the emptying valve.
Further, the cooling system further includes: a nitrogen gas replacement pipe which sequentially penetrates through the vault of the outer tank, the heat insulation material and the suspended ceiling of the inner tank to enter the inner tank so as to provide nitrogen gas to the inner tank; the nitrogen displacement switch valve is arranged on the nitrogen displacement pipe and can be controlled in switching state; before said step 1, the method further comprises:
step 01-2: opening the nitrogen replacement switch valve to enable nitrogen to enter the inner tank along the nitrogen replacement pipe so as to replace air in the inner tank;
step 02-2: and closing the nitrogen replacement switch valve under the condition that the oxygen and water vapor contents in the inner tank meet the standard requirements.
Further, the cooling system further includes: the low-temperature liquid hydrocarbon input pipe is connected with the low-temperature liquid hydrocarbon output main pipe, sequentially penetrates through the vault of the outer tank, the heat insulation material and the suspended ceiling of the inner tank, and enters the inner tank; the low-temperature liquid hydrocarbon input switch valve is positioned on the low-temperature liquid hydrocarbon input pipe and can be controlled in switch state; then after said step 02-2, before said step 1, the method further comprises:
step 03-2: opening the low-temperature liquid hydrocarbon input switch valve to enable gaseous hydrocarbon on the low-temperature liquid hydrocarbon transport ship to enter the inner tank along a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe and a low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship;
step 04-2: and when the temperatures of the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship all reach the standard requirements, closing the low-temperature liquid hydrocarbon input switch valve.
Further, the cooling system further comprises a draft tube located inside the inner vessel with an open inlet opposite the output end of the cryogenic liquid hydrocarbon input tube; then after the step 4, a step 5 is further included: opening the low-temperature liquid hydrocarbon input switch valve, enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship to sequentially flow into the drainage tube along the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship, and enter the inner tank along the drainage tube until the transportation stop condition is met, and closing the low-temperature liquid hydrocarbon input switch valve; wherein the output stopping condition is as follows: the total amount of the low-temperature liquid hydrocarbon inside the inner tank reaches the rated volume of the inner tank, and/or the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship is completely output.
Further, the cooling system further includes: a combustible gas discharge pipe communicated with the gas phase space in the inner tank, sequentially penetrating through the suspended ceiling of the inner tank, the heat insulating material and the vault of the outer tank and connected with a torch system; the combustible gas discharge pipe is provided with a combustible gas discharge switch valve with controllable switch state; said step 03-2 further comprises: opening the combustible gas discharge switch valve to discharge the mixed gas of gaseous hydrocarbon and nitrogen in the inner tank along the combustible gas discharge pipe and burn the mixed gas by the torch system;
in the step 1, after the gaseous hydrocarbon obtained by gasifying the low-temperature liquid hydrocarbon diffused into the inner tank displaces the nitrogen gas in the inner tank, and the nitrogen gas content in the inner tank meets the specification, the step 1 further includes a step 11: and closing the combustible gas discharge switch valve.
Further, the cooling system also comprises a gaseous hydrocarbon output pipe and a gaseous hydrocarbon output switch valve which is arranged on the gaseous hydrocarbon output pipe and has a controllable switch state; one end of the gaseous hydrocarbon output pipe is communicated with the gas phase space on the low-temperature liquid hydrocarbon transport ship, and the other end of the gaseous hydrocarbon output pipe sequentially penetrates through the vault of the outer tank, the heat insulating material and the suspended ceiling of the inner tank to enter the inner tank and is communicated with the gas phase space in the inner tank; then after said step 11 the method further comprises: and opening the gaseous hydrocarbon output switch valve to enable the gaseous hydrocarbon in the inner tank to enter the gas phase space on the low-temperature liquid hydrocarbon transport ship along the gaseous hydrocarbon output pipe.
Further, the cooling system also comprises a low-temperature liquid hydrocarbon flow regulating valve with controllable opening degree, which is positioned on the cooling straight pipe; then
The method for enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transportation ship to reach the nozzle along the cooling pipeline in the step 1 is as follows: opening the low temperature liquid hydrocarbon flow regulating valve to enable the low temperature liquid hydrocarbon on the low temperature liquid hydrocarbon carrier to reach the nozzle along the cooling pipeline;
the method for stopping the low-temperature liquid hydrocarbon from entering the inner tank along the cooling pipeline in the step 2 comprises the following steps: closing the low temperature liquid hydrocarbon flow regulating valve, stopping the low temperature liquid hydrocarbon from entering the inner tank interior along the cooling line;
the method for finishing cooling in the step 4 comprises the following steps: closing the low temperature liquid hydrocarbon flow regulating valve and stopping the low temperature liquid hydrocarbon from entering the inner tank along the cooling line.
The invention has the beneficial effects that: in the invention, because the low-temperature liquid hydrocarbon carried by the low-temperature liquid hydrocarbon carrier sequentially flows through the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the cooling straight pipe, enters the low-temperature liquid hydrocarbon dispersion pipe from the joint of the cooling straight pipe and the low-temperature liquid hydrocarbon dispersion pipe at the central point of the edge ring pipe, is dispersed by the low-temperature liquid hydrocarbon dispersion pipe and then enters the edge ring pipe, then flows out from the openings uniformly distributed at intervals at the lower part of the edge ring pipe, and is sprayed and atomized by the nozzles connected on the openings to be injected in all directions, and the low-temperature liquid hydrocarbon dispersion pipe passes through the central point of the edge ring pipe, so the low-temperature liquid hydrocarbon dispersion pipe is symmetrically distributed relative to the edge ring pipe, therefore, the low-temperature liquid hydrocarbon dispersion pipe has uniform dispersion effect on the low-temperature liquid hydrocarbon, namely, the flow of the low-temperature liquid, this allows the same flow of cryogenic liquid hydrocarbon to exit each opening in the edge collar. In addition, because the nozzle which has the function of spraying and atomizing the low-temperature liquid hydrocarbon is arranged at the opening, the sprayed and atomized low-temperature liquid hydrocarbon can be contacted with any point of the inner tank to be cooled no matter the low-temperature liquid hydrocarbon is gasified into gaseous hydrocarbon and gradually descends towards the bottom of the inner tank or falls down towards the bottom of the inner tank in the form of liquid drops after being injected in all directions, namely any point on the inner tank can be contacted with the low-temperature liquid hydrocarbon to be cooled. In conclusion, the invention overcomes the two problems in the prior art, and ensures that the cooling speed of each point in the inner tank is uniform, thereby ensuring that the cooling speed of the low-temperature liquid hydrocarbon storage tank is uniform.
Drawings
FIG. 1 is a block diagram of a cryogenic liquid hydrocarbon storage tank and its cooling system provided by the prior art;
FIG. 2 is a block diagram of a prior art cooling loop;
FIG. 3 is a block diagram of a cryogenic liquid hydrocarbon storage tank and its cooling system provided by the present invention;
FIG. 4 is a block diagram of one embodiment of a cooling loop provided by the present invention;
FIG. 5 is a directional diagram of two staggered openings in a cooling collar provided by the present invention;
FIG. 6 is a schematic structural view of a nozzle provided in the present invention;
FIG. 7 is a schematic diagram of a temperature sensor arrangement according to the present invention;
fig. 8 is a flowchart of a cooling method of a cryogenic liquid hydrocarbon storage tank according to the present invention.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
Fig. 3 is a structural diagram of a low-temperature liquid hydrocarbon storage tank and a cooling system thereof according to the present invention. As shown in fig. 1, the cryogenic liquid hydrocarbon storage tank of the present invention includes: an outer vessel 302 and an inner vessel 301 located inside the outer vessel 302; the suspended ceiling 303 of the inner tank 301 is connected with the vault of the outer tank 302 through a hanger bar 305; a heat insulating material 304 is filled between the inner surface of the outer tank 302 and the outer surface of the inner tank 301; a nitrogen purging pipe 306 penetrates through the vault of the outer tank 302 to enter the space between the inside of the outer tank 302 and the outside of the inner tank 301, and a nitrogen purging switch valve 307 is arranged on the nitrogen purging pipe 306; a vent line 325 having one end communicating with the outside atmosphere and the other end communicating with the gas phase space inside the dome of the outer tank 302 through the dome of the outer tank 302; an adjustable vent valve 326 is positioned on the vent line 325. In fig. 3, the cooling system for a cryogenic liquid hydrocarbon storage tank according to the present invention includes: a cryogenic liquid hydrocarbon carrier 308 that carries cryogenic liquid hydrocarbons; a ship unloading arm 309 connected to a low-temperature liquid hydrocarbon output pipe of the low-temperature liquid hydrocarbon carrier 308; a low-temperature liquid hydrocarbon output header 310 connected to an output end of the ship unloading arm 309 to output low-temperature liquid hydrocarbon; a cooling straight pipe 311 connected with the low-temperature liquid hydrocarbon output main pipe 310 and sequentially passing through the vault of the outer tank 302, the heat insulating material 304 and the suspended ceiling 303 of the inner tank 301 to enter the inner tank 301; a cooling collar 315 located in a horizontal plane inside the inner vessel 301.
Wherein cooling loop 315 comprises an edge loop and a low temperature liquid hydrocarbon dispersion pipe 328 for dispersing low temperature liquid hydrocarbon passing through the center point of the edge loop; the edge ring pipe is communicated with the low-temperature liquid hydrocarbon dispersion pipe 328, and the low-temperature liquid hydrocarbon dispersion pipe 328 is communicated with the cooling straight pipe 311 at the central point of the edge ring pipe;
the lower portion of the edge collar has openings spaced evenly and each opening is connected to a hollow nozzle 317 which provides spraying and atomizing of the exiting low temperature liquid hydrocarbon.
In the invention, the outer tank for supporting the inner tank and the enclosure heat insulation material can be made of carbon steel, and the low-temperature liquid hydrocarbon output pipe of the low-temperature liquid hydrocarbon transport ship, the low-temperature liquid hydrocarbon delivery pipeline on the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe, the cooling straight pipe, the cooling circular pipe and other pipelines for delivering the low-temperature liquid hydrocarbon and the inner tank are made of low-temperature resistant stainless steel with enough strength. The selection of the heat insulating material between the inner tank and the outer tank takes the heat insulating function into consideration and simultaneously bears the weight of the inner tank and the stored low-temperature liquid hydrocarbon, and the heat insulating material at the bottom of the inner tank can be realized by using foam glass bricks with good compressive strength and low heat conductivity coefficient and adopting a multilayer laying mode; for the annular space between the outer side surface of the inner tank and the inner side surface of the outer tank, in order to facilitate the injection and filling of the annular space from the top of the storage tank and prevent the thermal insulation material from damaging the inner tank and the outer tank due to overlarge density, the thermal insulation material needs to have good fluidity and smaller density, expanded perlite (also called pearlite sand) can be adopted, meanwhile, considering that the inner tank is in a normal temperature state in the construction and installation process, the inner tank is in a low temperature state when low-temperature liquid hydrocarbon is stored in actual operation, and metal has a contraction phenomenon along with the reduction of temperature, a layer of elastic glass cloth can be firstly paved between the outer side surface of the inner tank and the inner side surface of the outer tank, and then the pearlite sand is refilled, because the elastic glass cloth has strong expansion capacity, the elastic glass cloth can easily adapt to the volume change caused by the expansion and contraction of the metal, so that the annular space between the outer, meanwhile, the elastic glass cloth can also effectively absorb the load generated by the pearlife filled in the annular space, and the load is prevented from being transmitted to the inner tank to cause instability and damage of the inner tank; for the heat insulating material in the gap between the inner tank suspended ceiling and the outer tank vault, considering that the temperature is higher than that of low-temperature liquid hydrocarbon and the heat insulating material needs to be laid conveniently, the space is filled with a heat insulating blanket.
The nitrogen conveyed by the nitrogen purging pipe can exhaust the air in the space between the inner tank and the outer tank, thereby preventing the water vapor in the air from pre-condensing to destroy the heat insulation performance of the heat insulation material, and simultaneously preventing the gaseous hydrocarbon overflowing from the inner tank from burning and exploding when meeting oxygen.
The invention utilizes the cold energy of the low-temperature liquid hydrocarbon loaded by a low-temperature liquid hydrocarbon transport ship to cool a cooling pipeline (comprising a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe, a cooling straight pipe and a cooling ring pipe of the low-temperature liquid hydrocarbon transport ship) and a low-temperature liquid hydrocarbon storage tank (comprising an inner tank, an outer tank and a heat insulating material), wherein the low-temperature liquid hydrocarbon can be gasified into gaseous hydrocarbon at a certain position in the cooling pipeline or the inner tank, and the gasification is caused by the fact that the temperature of the cooling pipeline or the inner tank is higher than the boiling point of the low-temperature liquid hydrocarbon, so that the gaseous hydrocarbon can also provide the cold energy for cooling the cooling pipeline and the inner tank.
Since the edge ring pipe is a symmetrical figure (such as a central symmetrical figure like a circular ring, a regular hexagon, a regular octagon, etc. or an equiaxed symmetrical figure like an equilateral triangle, a regular pentagon, a regular heptagon, etc.), the low-temperature liquid hydrocarbon dispersion pipe passes through the central point of the edge ring pipe, if the edge ring pipe is in a central symmetrical pattern, each branch pipe of the low-temperature liquid hydrocarbon dispersion pipe passes through the symmetrical center, if the edge collar is axisymmetric, each branch of the low temperature liquid hydrocarbon dispersion pipe passes through its symmetry axis, or symmetrically distributed at two sides of the symmetry axis, therefore, each branch pipe of the low-temperature liquid hydrocarbon dispersion pipe can play a role in uniformly distributing the low-temperature liquid hydrocarbon, namely, the low-temperature liquid hydrocarbon entering the low-temperature liquid hydrocarbon dispersion pipe through the connecting point of the cooling straight pipe and the low-temperature liquid hydrocarbon dispersion pipe is uniformly distributed into each branch pipe, so that the flow of the cryogenic liquid hydrocarbon exiting from each opening after entering the edge collar is the same. This overcomes the problem of the prior art in which the connection point of the cooling straight tube to the cooling loop is at the edge of the cooling loop, resulting in different flow rates of the low temperature liquid hydrocarbon exiting each opening.
Fig. 4 is a block diagram of one embodiment of a cooling collar provided in accordance with the present invention, viewed from a vertical upward perspective, i.e., from a bottom view of the cooling collar. As shown in fig. 4, the edge ring pipe 402 in this embodiment is a circular ring with a central symmetry, and the low temperature liquid hydrocarbon dispersion pipe 401 has four branch pipes, and adjacent straight pipes are perpendicular to each other and pass through the center of the edge ring pipe. The connection position of the cooling straight pipe 311 and the low-temperature liquid hydrocarbon dispersion pipe 401 is at the center of the edge ring pipe 402. Thus, as shown in fig. 4, after entering the connection position of the low-temperature liquid hydrocarbon dispersion pipe 401 (i.e., the center of the edge ring pipe 402) through the straight cooling pipe 311, the low-temperature liquid hydrocarbon is divided into four branches with uniform flow rate, and flows into the edge ring pipe 402 from four branch pipes, and the low-temperature liquid hydrocarbon flowing into the edge ring pipe 402 from each branch pipe is further divided into two branches with uniform flow rate, flows out from the opening provided on the edge ring pipe 402, and is sprayed and atomized by the nozzles (shown as 4171 and 4172 in fig. 4) connected to the opening to be injected in various directions. It can be seen that the structure of the low temperature liquid hydrocarbon dispersion pipe 401 and the connection relationship between the low temperature liquid hydrocarbon dispersion pipe and the edge ring pipe 402 effectively overcome the problem of uneven low temperature liquid hydrocarbon outflow of each opening caused by the connection of the cooling straight pipe to the edge of the cooling ring pipe in the prior art. Meanwhile, each opening is also connected with a hollow nozzle which has the functions of spraying and atomizing the flowing-out low-temperature liquid hydrocarbon, so that the low-temperature liquid hydrocarbon can be sprayed in all directions under the spraying and atomizing functions of the nozzle, all points on the inner tank can be contacted with the low-temperature liquid hydrocarbon (or the gasified gaseous hydrocarbon thereof) to be cooled, and thus, the inner surface of the whole inner tank is in the cooling range of the low-temperature liquid hydrocarbon, and the cooling becomes uniform.
Therefore, in the invention, after the low-temperature liquid hydrocarbon carried by the low-temperature liquid hydrocarbon carrier sequentially flows through the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the cooling straight pipe, the low-temperature liquid hydrocarbon enters the low-temperature liquid hydrocarbon dispersion pipe from the joint of the cooling straight pipe and the low-temperature liquid hydrocarbon dispersion pipe at the central point of the edge ring pipe, the low-temperature liquid hydrocarbon enters the edge ring pipe after being dispersed by the low-temperature liquid hydrocarbon dispersion pipe, then flows out from the openings uniformly distributed at intervals at the lower part of the edge ring pipe, and is sprayed and atomized by the nozzles connected to the openings to be injected in all directions, and the low-temperature liquid hydrocarbon dispersion pipe passes through the central point of the edge ring pipe, so that the low-temperature liquid hydrocarbon dispersion pipe is symmetrically distributed relative to the edge ring pipe, therefore, the low-temperature liquid hydrocarbon dispersion pipe has uniform dispersion effect on the low-temperature liquid hydrocarbon, this allows the same flow of cryogenic liquid hydrocarbon to exit each opening in the edge collar. In addition, because the nozzle which has the function of spraying and atomizing the low-temperature liquid hydrocarbon is arranged at the opening, the sprayed and atomized low-temperature liquid hydrocarbon can be contacted with any point of the inner tank to be cooled no matter the low-temperature liquid hydrocarbon is gasified into gaseous hydrocarbon and gradually descends towards the bottom of the inner tank or falls down towards the bottom of the inner tank in the form of liquid drops after being injected in all directions, namely any point on the inner tank can be contacted with the low-temperature liquid hydrocarbon to be cooled. In conclusion, the invention overcomes the two problems in the prior art, and ensures that the cooling speed of each point in the inner tank is uniform, thereby ensuring that the cooling speed of the low-temperature liquid hydrocarbon storage tank is uniform.
Because the invention can ensure that the cooling speed of each point in the inner tank is uniform, compared with the prior art, the invention has the advantage that the cooling speed is greatly improved.
As shown in fig. 4, the nozzles are identified by 4171 and 4172 with different numbers because the two nozzles are installed at different positions on the edge collar 402, i.e. the positions of the openings connected with the two nozzles are different on the edge collar 402. in the present invention, two adjacent openings on the edge collar 402 can be alternately arranged at two positions close to the center point of the edge collar and far from the center point of the edge collar, i.e. as shown in fig. 4, the opening connected with the nozzle 4171 and the opening connected with the nozzle 4172 are adjacent openings, the opening connected with the nozzle 4171 is far from the center point of the edge collar 402 (i.e. the center point thereof), and the opening connected with the nozzle 4172 is close to the center point of the edge collar 402, so that the low temperature liquid hydrocarbon flowing from the openings connected with the nozzles 4171 and 4172 can not flow vertically downward if not sprayed and atomized by the nozzles, but is directed obliquely downwards.
FIG. 5 is a directional diagram of two staggered openings in a cooling collar provided by the present invention. As shown in FIG. 5, the axis 4171-1 of the opening to which nozzle 4171 is connected is angled obliquely downward at an angle α to the vertically downward direction 501, and the axis 4172-1 of the opening to which nozzle 4172 is connected is also angled obliquely downward at an angle β to the vertically downward direction 501, as distinguished by the axis 4171-1 and 4172-1 of the two openings, as shown in FIG. 5, the axis 4171-1 pointing away from the vertical line 503 of the center point 502 of the edge collar 402 and the axis 4172-1 pointing toward the vertical line 503 of the center point 502.
In the embodiment of fig. 5, the low temperature liquid hydrocarbon dispersion pipe 401 is provided in the form of six branch pipes, the included angle between adjacent branch pipes is 60 °, and the edge ring pipe 402 in this embodiment is still circular, so that the low temperature liquid hydrocarbon flowing from the cooling straight pipe 311 is uniformly divided into 6 branch flows with the same flow rate after entering the low temperature liquid hydrocarbon dispersion pipe 401 through the central point 502, and the branch flows into the edge ring pipe 402 through the dispersion effect of the six branch pipes.
In the cooling system, the nozzle has a central axis, and an included angle between a downward direction and a vertically downward direction of the central axis is called a downward deviation angle of the central axis of the nozzle. As shown in FIG. 5, the central axis of the nozzle 4171 to which the opening distal from the center point 502 of the edge collar 402 is connected is oriented in a downward direction (i.e., the direction of the axis of the opening 4171-1) away from the vertical line 503 of the center point 502, and the central axis of the nozzle 4171 is angled downward (i.e., α above) between 30 and 60; the central axis of the nozzle 4172 to which the opening near the center point 502 of the edge collar 402 is connected is directed in a downward direction 4172-1 towards the vertical line 503 on which the center point 502 is located, and the central axis of the nozzle 4172 is also angled downward (i.e., β above) between 30-60.
Fig. 6 is a schematic structural view of a nozzle provided by the present invention. As shown in fig. 6, the nozzle includes a butt opening portion 601, a connection portion 602, a low-temperature liquid hydrocarbon spraying and atomizing portion 603, which are connected in order; wherein, the butt joint opening part 601 is a hollow pipeline, which is connected to the opening on the edge ring pipe (shown as reference numeral 402 in fig. 4 and 5), is communicated with the inside of the edge ring pipe, and can continuously convey the low-temperature liquid hydrocarbon flowing out from the opening; the connection portion 602 is a hollow pipe communicating with the butt opening portion 601, and can further convey the low-temperature liquid hydrocarbon and make it flow out from the end opening 6021 of its own pipe, and in addition, the connection portion 602 also serves as a connection buffer section of the butt opening portion 601 and the low-temperature liquid hydrocarbon spraying and atomizing portion 603; as shown in fig. 6, the low temperature liquid hydrocarbon spraying and atomizing part 603 is a spiral cone with a gradually decreasing spiral radius, and the low temperature liquid hydrocarbon flowing out from the end opening 6021 of the connecting part 602 hits the low temperature liquid hydrocarbon spraying and atomizing part 603 during the continuous flowing process, so as to be injected in all directions, which is the principle of the spraying and atomizing effect of the nozzle for the low temperature liquid hydrocarbon provided by the present invention, for example, at A, B in fig. 6, the low temperature liquid hydrocarbon flowing through A, B at two points is sprayed and atomized by the two points to be injected in all directions, and atomized low temperature liquid hydrocarbon is formed inside the inner tank, therefore, the present invention places the whole inner surface of the inner tank within the cooling range of the low temperature liquid hydrocarbon, which greatly increases the cooling range of the low temperature liquid hydrocarbon, and also makes the cooling more uniform.
The cooling system shown in fig. 3 further includes a low-temperature liquid hydrocarbon flow regulating valve 313 with controllable opening degree located on the cooling straight pipe 311 and a flow meter 327 capable of indicating the flow rate of the low-temperature liquid hydrocarbon in the cooling straight pipe 311, the flow rate of the low-temperature liquid hydrocarbon in the cooling straight pipe 311 can be obtained by reading the reading of the flow meter 327, and the opening and closing of the cooling straight pipe 311 and the flow rate of the low-temperature liquid hydrocarbon conveyed by the cooling straight pipe 311 can be controlled by regulating the opening degree of the low-temperature liquid hydrocarbon flow regulating valve 313, so as to control the cooling speed of the inner tank, and prevent the low-temperature liquid hydrocarbon storage.
The system further includes a low-temperature liquid hydrocarbon input pipe 312 connected to the low-temperature liquid hydrocarbon output manifold 310 and sequentially passing through the dome of the outer tank 302, the insulating material 304, and the ceiling 303 of the inner tank 301 into the interior of the inner tank 301, and a low-temperature liquid hydrocarbon input switching valve 314 having a controllable switching state on the low-temperature liquid hydrocarbon input pipe 312, and the cooling system may further include a drain pipe 316 located in the interior of the inner tank 301 with an inlet opposite to the output end of the low-temperature liquid hydrocarbon input pipe 312, and an opening of the drain pipe 316 is opened. Thus, after the low-temperature liquid hydrocarbon storage tank is cooled, the low-temperature liquid hydrocarbon flow regulating valve 313 can be closed, the cooling input pipeline of the low-temperature liquid hydrocarbon is cut off, and the low-temperature liquid hydrocarbon input switching valve 314 is opened, so that the low-temperature liquid hydrocarbon input pipe 312 is opened, and the low-temperature liquid hydrocarbon conveyed by the ship unloading arm sequentially enters the inner tank 301 through the low-temperature liquid hydrocarbon output header pipe 310 and the low-temperature liquid hydrocarbon input pipe 312, is drained through the drainage pipe 316 and is finally stored in the inner tank 301.
The cooling system also comprises a gas output pipe 320 which is communicated with a gas phase space (the component can be gaseous hydrocarbon or a mixed gas of the gaseous hydrocarbon and nitrogen) in the inner tank 301, sequentially passes through the suspended ceiling 303 of the inner tank 301, the heat insulating material 304 and the vault of the outer tank 302 and is connected with a torch system; the gas outlet pipe 320 is provided with a safety valve 321 with a certain take-off pressure. Thus, when the gas pressure in the gas phase space inside the inner tank 301 is too high, the safety valve 321 jumps to conduct the gas output pipe 320, so that the gaseous hydrocarbon or the mixture of the gaseous hydrocarbon and the nitrogen inside the inner tank 301 can reach the torch system to be burned, and the gaseous hydrocarbon is prevented from being excessively pressurized to damage the low-temperature liquid hydrocarbon storage tank or cause accidents such as fire and explosion.
Of course, in the initial stage of cooling, because the cooling pipeline, the inner tank, the heat insulating material and the outer tank are hot, the input low-temperature liquid hydrocarbon can be gasified to generate gaseous hydrocarbon, and then the gaseous hydrocarbon or the mixture of the gaseous hydrocarbon and nitrogen can be output and combusted in a mode of arranging a gaseous hydrocarbon discharge pipeline, wherein the gaseous hydrocarbon discharge pipeline is arranged at one end outside the outer tank 302 and connected with a torch system, and the other end penetrates through the vault of the outer tank 302, the heat insulating material and the suspended ceiling 303 of the inner tank 301 in sequence to enter the interior of the inner tank 301 and is communicated with the gas phase space in the inner tank 301.
The cooling system may further include a gaseous hydrocarbon output pipe 318 having one end communicating with the gas phase space on the cryogenic liquid hydrocarbon carrier 308 and the other end sequentially passing through the dome of the outer tank 302, the insulation material 304 and the ceiling 303 of the inner tank 301 to enter the inside of the inner tank 301 and communicating with the gas phase space inside the inner tank 301, and a gaseous hydrocarbon output switching valve 319 whose switching state is controllable may be further installed on the gaseous hydrocarbon output pipe 318. Thus, after the air inside the inner tank 301 is completely replaced with nitrogen and the nitrogen in the space is completely replaced with gaseous hydrocarbon (generated in the initial stage of cooling), the gaseous hydrocarbon output on-off valve 319 is opened to communicate the gas phase space (containing gaseous hydrocarbon) inside the inner tank 301 with the gas phase space (containing gaseous hydrocarbon) of the cryogenic liquid hydrocarbon carrier 308, thereby returning the gaseous hydrocarbon in the gas phase space of the inner tank 301 to the gas phase space of the cryogenic liquid hydrocarbon carrier 308.
In order to determine whether the nitrogen inside the inner tank 301 is completely replaced with the gaseous hydrocarbon, i.e., whether the nitrogen concentration inside the inner tank 301 is low to the standard specified by the specification, the system further includes a nitrogen concentration sampling detector 324 that detects the nitrogen concentration inside the inner tank 301. Thus, the gaseous hydrocarbon output switching valve 319 may be opened when the nitrogen concentration outputted from the nitrogen concentration sampling detector 324 meets the standards specified by the specifications, and otherwise, the gaseous hydrocarbon output switching valve 319 is not opened.
In the present invention, in order to determine whether the cooling rate of the low-temperature liquid hydrocarbon storage tank and the temperature difference at each point meet the standard, a certain number of temperature sensors are further disposed on the inner surface of the inner tank 301 (including the ceiling 303 thereof). Fig. 7 is a schematic distribution diagram of the temperature sensors provided by the present invention. As shown in fig. 7, the inner vessel 301 is a hollow cylindrical flat bottom cup-shaped container, the ceiling 303 is circular, and the temperature sensors disposed inside the inner vessel are all identified by reference numeral 702. Temperature sensors are uniformly distributed on the inner bottom surface of the inner tank 301 (namely the part of the bottom surface of the inner tank 301 which is positioned in the inner tank and is contacted with the low-temperature liquid hydrocarbon) and more than one concentric circle 701 with the center of the circle of the inner bottom surface as the center of the circle; temperature sensors are distributed on the inner side wall of the inner tank 301 (i.e. the surface of the side wall located inside the inner tank 301) at different heights, and as shown in fig. 7, the height difference between the adjacent temperature sensors at the bottom of the inner side wall is smaller than that of the adjacent temperature sensors at the upper part of the inner side wall, i.e. the density of the temperature sensors at the bottom of the inner side wall is higher, because at the end of the cooling process, the bottom of the inner tank 301 only stores low-temperature liquid hydrocarbons at a certain height (e.g. 0.5 m), and the inner side wall at a higher position only contacts with gaseous hydrocarbons, so the temperature difference at the bottom of the inner side wall should be paid more. Temperature sensors are also uniformly distributed on the upper bottom surface of the ceiling 303 and more than one concentric circle 703 taking the circle center of the upper bottom surface as the circle center. In addition, the temperature sensors (including the temperature sensors on the inner bottom surface and the inner side wall of the inner tank 301 and the temperature sensor on the upper bottom surface of the ceiling 303) are all connected with a temperature indicator to indicate the temperature change condition of each point in the inner tank at any time, if the cooling speed measured by one or more temperature sensors exceeds 3 ℃/hour or the temperature difference measured by any two temperature sensors exceeds 30 ℃, the low-temperature liquid hydrocarbon flow regulating valve 313 is immediately closed to stop the input of the low-temperature liquid hydrocarbon, and when the cooling speed measured by all the sensors does not exceed 3 ℃/hour and the temperature difference measured by any two temperature sensors does not exceed 30 ℃, the low-temperature liquid hydrocarbon flow regulating valve 313 is opened again.
The value of low temperature liquid hydrocarbon storage tank itself and the low temperature liquid hydrocarbon of storage is very big, in case reveal, probably cause safety accident such as burning, explosion and serious environmental pollution, consequently, in order to take precautions against the automatic control system and break down the impaired problem of low temperature liquid hydrocarbon storage tank that causes, can also set up the alarm of a certain amount to in time remind the staff through the mode of reporting to the police when the problem appears. As shown in fig. 3, the cooling system further includes a temperature indicating alarm 323 connected to the temperature sensors on the inner bottom surface and the inner side wall of the inner tank 301 and the temperature sensor on the upper bottom surface of the ceiling 303, and an air pressure indicating alarm 322 that detects, indicates the air pressure inside the inner tank 301, and alarms when the air pressure exceeds a standard.
Therefore, the method can ensure the safe and reliable cooling of the low-temperature liquid hydrocarbon storage tank by combining an automatic control system with a manual alarm control mode.
The present invention also provides a cooling method of a cryogenic liquid hydrocarbon storage tank based on the cooling system of the cryogenic liquid hydrocarbon storage tank shown in fig. 3 and the components of the cooling system shown in fig. 4 to 7. FIG. 8 is a flow chart of a method of cooling a cryogenic liquid hydrocarbon storage tank according to the present invention. In the method, a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe, a cooling straight pipe and a cooling ring pipe of a low-temperature liquid hydrocarbon transport ship form a cooling pipeline. As shown in fig. 8, the method includes:
step 801: the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship reaches the nozzle along the cooling pipeline, and the outflowing low-temperature liquid hydrocarbon is sprayed and atomized by the nozzle to diffuse into the inner tank.
This step is based on the cooling system of the cryogenic liquid hydrocarbon storage tank shown in fig. 3 and the components of the cooling system shown in fig. 4-6. As shown in fig. 3, the low-temperature liquid hydrocarbon carried by the low-temperature liquid hydrocarbon carrier 308 sequentially passes through the low-temperature liquid hydrocarbon output pipe, the ship unloader arm 309, the low-temperature liquid hydrocarbon output manifold 310, the cooling straight pipe 311 and the cooling ring pipe 315 to reach the opening on the edge ring pipe (402 in fig. 4) in the cooling ring pipe 315, and then flows out of the hollow pipe of the nozzle (4171 or 4172), and is sprayed and atomized by the low-temperature liquid hydrocarbon spraying and atomizing part (603 in fig. 6) to be injected in all directions, so that the low-temperature liquid hydrocarbon is spread out inside the inner tank, the surface of the whole inner tank is completely contained in the coverage range of the inner tank, and the cooling uniformity of the low-temperature liquid hydrocarbon storage tank is ensured.
Step 802: and judging whether the temperature drop temperature difference condition is satisfied, if so, executing a step 804, otherwise, executing a step 803.
The temperature drop difference conditions here include: the temperature drop speed of any point on the inner bottom surface, the inner side wall and the upper bottom surface of the suspended ceiling of the inner tank is not more than 3 ℃/hour, and the temperature difference between any two points is not more than 30 ℃. This is a specification-required cooling requirement for the cryogenic liquid hydrocarbon storage tank (and particularly its inner vessel) which, if not met, may cause damage to the inner or outer vessel.
This step is based on the temperature sensor profile shown in fig. 7. The temperature sensor in figure 7 detects the temperature of any point on the interior bottom surface of inner tank and the last bottom surface of inside wall, furred ceiling, through the temperature controller that temperature sensor connected, can judge whether the temperature drop difference condition has established.
Step 803: the cryogenic liquid hydrocarbon is stopped from entering the interior of the inner vessel along the cooling line and the process returns to step 802.
This step may be performed based on the cooling system shown in fig. 3. By closing the low temperature liquid hydrocarbon flow regulating valve 313 in fig. 3, the feeding of the low temperature liquid hydrocarbon along the cooling line into the interior of the inner vessel can be stopped.
Returning to step 802 means that the step is not stopped until the temperature drop difference condition is satisfied, and step 804 is executed after step 802, and if the temperature drop difference condition is not satisfied, the step 802 and the step are executed in a circulating manner.
Step 804: and (4) judging whether the temperature of any point on the inner bottom surface of the inner tank is not higher than the set temperature, if so, executing step 805, otherwise, executing step 801.
The set temperature set in the present invention is a temperature higher than and very close to the boiling point of the cryogenic liquid hydrocarbon, and if the boiling point of the Liquefied Natural Gas (LNG) is-160 deg.c, the set temperature may be set to-158 deg.c. When the temperature (measured by the temperature sensor) at all points on the inner bottom surface of the inner tank is not higher than the set temperature, meaning that the cooling process is about to end, step 805 may be performed to bring the liquid level in the inner tank to its set level, and then the cooling process may be ended. If it is not satisfied that the temperature at any point on the inner bottom surface of the inner tank is not higher than the set temperature, it means that the cooling process still takes a long time to finish, and the process returns to step 801.
Step 805: the cryogenic liquid hydrocarbon continues along the cooling line to the nozzle and into the interior of the inner vessel under the spray and atomization of the nozzle until the level of cryogenic liquid hydrocarbon inside the inner vessel reaches the level set point, and step 806 is performed.
This step is performed when the determination result in step 804 is yes, and the purpose of this step is to make the liquid level inside the inner tank reach a predetermined height setting value (for example, the height setting value inside the liquid ethylene storage tank can be set to 0.5 m), so as to ensure that the cooling effect is not lost quickly (even if the low-temperature liquid hydrocarbon storage tank is heated to a certain extent, this part of heat is absorbed by the low-temperature liquid hydrocarbon and does not cause the temperature rise of the low-temperature liquid hydrocarbon storage tank).
Step 806: and finishing cooling.
Before step 801, the method may further include a nitrogen purge step to vent air from the space between the inner tank 301 and the outer tank 302 shown in fig. 3, to prevent contact of oxygen with gaseous hydrocarbons, and water vapor from condensing to cause the insulating material 304 to lose its insulating function. The nitrogen purging step comprises:
step 01-1: opening the nitrogen purge switching valve 307 in fig. 3 to allow nitrogen to enter the space between the inside of the outer tank 302 and the outside of the inner tank 301 through the nitrogen purge pipe 306 to replace the air in the space; simultaneously opening a vent valve 326 on the vent line 325 to vent the displaced air to the outside atmosphere;
step 02-1: in the case where the oxygen and water vapor contents of the space between the inside of the outer tank 302 and the outside of the inner tank 301 meet the specification, and the nitrogen gas pressure is greater than the atmospheric pressure outside the outer tank 302, the nitrogen purge switching valve 307 and the purge valve 326 are closed, thereby terminating the input of nitrogen gas and the discharge of air.
In addition, the cooling system provided by the present invention may further include an air replacement device inside the inner tank, the air replacement device including: a nitrogen gas replacement pipe which sequentially passes through the dome of the outer tank 302, the heat insulating material 304, and the ceiling 303 of the inner tank 301 in fig. 3 into the inside of the inner tank 301 to supply nitrogen gas to the inside of the inner tank 301; the on-off state of the nitrogen replacement pipe is controllable. With this air displacement device, the method can perform a displacement operation of the air inside the inner tank before step 801, the displacement operation including:
step 01-2: opening the nitrogen replacement switch valve to enable nitrogen to enter the inner tank along the nitrogen replacement pipe so as to replace air in the inner tank;
step 02-2: and closing the nitrogen replacement switch valve under the condition that the oxygen and water vapor contents in the inner tank meet the standard requirements.
Certainly, the nitrogen purging step and the air replacement work both need to detect the content of oxygen, water vapor and the like in the corresponding space, and further judge whether the purging or replacement work reaches the standard, therefore, the cooling system provided by the invention also needs to comprise corresponding instruments for detecting the content of oxygen, water vapor and the like, if the judgment is carried out manually, a display device matched with the corresponding instrument is needed, and if the judgment is carried out automatically by a machine, a controller connected with the instrument for detecting the content of oxygen, water vapor and the like is needed.
The cooling system provided by the invention further comprises: in fig. 3, a low-temperature liquid hydrocarbon input pipe 312 connected to a low-temperature liquid hydrocarbon output header pipe 310 and sequentially passing through the dome of the outer tank 302, the insulating material 304, and the ceiling 303 of the inner tank 301 into the interior of the inner tank 301; a low-temperature liquid hydrocarbon input switching valve 314 whose switching state is controllable, which is provided on the low-temperature liquid hydrocarbon input pipe 312; then after the above-mentioned step 02-2 is finished, that is, after the air inside the inner tank is completely replaced, before step 801, the cooling method may further include a cooling operation of the low-temperature liquid hydrocarbon input line, the cooling operation including:
step 03-2: opening the low-temperature liquid hydrocarbon input switch valve 314 in fig. 3, so that the gaseous hydrocarbon on the low-temperature liquid hydrocarbon transport ship 308 enters the inner tank 301 along the low-temperature liquid hydrocarbon output pipe of the low-temperature liquid hydrocarbon transport ship 308, the ship unloading arm 309, the low-temperature liquid hydrocarbon output main pipe 310 and the low-temperature liquid hydrocarbon input pipe 312, thereby cooling the pipelines by using the cooler gaseous hydrocarbon;
step 04-2: when the temperatures of the low-temperature liquid hydrocarbon output pipe, the ship unloading arm 309, the low-temperature liquid hydrocarbon output main pipe 310 and the low-temperature liquid hydrocarbon input pipe 312 of the low-temperature liquid hydrocarbon transport ship 308 all reach the specification requirements, the low-temperature liquid hydrocarbon input switch valve 314 is closed, and therefore the cooling work of the pipelines by the gaseous hydrocarbon is stopped.
The cooling system of fig. 3 also includes a draft tube 316 located inside the inner vessel 301 with an open inlet opposite the output end of the cryogenic liquid hydrocarbon input tube 312. Thus, after step 806, a low temperature liquid hydrocarbon input step 807 is also included: opening the low-temperature liquid hydrocarbon input switch valve 314, enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship 308 to sequentially flow into the drainage pipe 316 along the low-temperature liquid hydrocarbon output pipe, the ship unloading arm 309, the low-temperature liquid hydrocarbon output main pipe 310 and the low-temperature liquid hydrocarbon input pipe 312 of the low-temperature liquid hydrocarbon transport ship 308, and enter the inner tank 301 along the drainage pipe 316 until the transportation stop condition is met, and closing the low-temperature liquid hydrocarbon input switch valve 314; wherein the output stopping condition is as follows: the total amount of cryogenic liquid hydrocarbon inside inner tank 301 reaches the nominal volume of inner tank 301 and/or the cryogenic liquid hydrocarbon on cryogenic liquid hydrocarbon carrier 308 has been completely exported.
The cooling system in fig. 3 further includes: a combustible gas discharge pipe 320 communicated with the gas phase space inside the inner tank 301, sequentially passing through the suspended ceiling 303 of the inner tank 301, the heat insulating material 304 and the dome of the outer tank 302, and connected to the flare system; the combustible gas discharge pipe 320 is provided with a combustible gas discharge on-off valve 321 whose on-off state is controllable. Step 03-2 may further comprise: opening the combustible gas discharge switch valve 321 to discharge the mixed gas of gaseous hydrocarbon and nitrogen in the inner tank 301 along the combustible gas discharge pipe 320, and burning the mixed gas by the torch system;
in step 801, after the gaseous hydrocarbon obtained by gasifying the low-temperature liquid hydrocarbon diffused into the inner tank 301 displaces the nitrogen gas in the inner tank 301 to make the nitrogen gas content in the inner tank 301 meet the specification, step 801 further includes step 11: the combustible gas discharge switching valve 321 is closed.
As shown in fig. 3, the cooling system further includes a gaseous hydrocarbon output pipe 318 and a gaseous hydrocarbon output on-off valve 319, whose on-off state is controllable, attached to the gaseous hydrocarbon output pipe 318; one end of the gaseous hydrocarbon output pipe 318 is communicated with the gas phase space on the low-temperature liquid hydrocarbon transport ship 308, and the other end of the gaseous hydrocarbon output pipe passes through the vault of the outer tank 302, the heat insulating material 304 and the suspended ceiling 303 of the inner tank 301 in sequence, enters the inner tank 301 and is communicated with the gas phase space inside the inner tank 301; then after step 11, the method may further comprise: the gaseous hydrocarbon output switch valve 319 is opened to allow the gaseous hydrocarbon inside the inner tank 301 to enter the gas phase space on the low-temperature liquid hydrocarbon carrier 308 along the gaseous hydrocarbon output pipe 318, which not only prevents the excessive air pressure inside the inner tank 301, but also reduces the energy consumption and the environmental pollution caused thereby.
The cooling system shown in fig. 3 further includes a low-temperature liquid hydrocarbon flow rate regulating valve 313 with a controllable opening degree on the cooling straight pipe 311, and the valve can be used for regulating the input speed of the low-temperature liquid hydrocarbon, so as to control the cooling speed of the low-temperature liquid hydrocarbon storage tank. The specific regulation method is as follows:
the method for enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship to reach the nozzle along the cooling pipeline in the step 801 is as follows: opening the low-temperature liquid hydrocarbon flow regulating valve 313 to enable the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship 308 to reach the nozzle 317 along the cooling pipeline, so that the cooling pipeline is cooled by using the cold energy of the low-temperature liquid hydrocarbon or the gaseous hydrocarbon formed by gasifying the low-temperature liquid hydrocarbon;
the method for stopping the low-temperature liquid hydrocarbon from entering the inner tank along the cooling pipeline in the step 803 is as follows: closing the low-temperature liquid hydrocarbon flow regulating valve 313 to stop the low-temperature liquid hydrocarbon from entering the inner tank 301 along the cooling pipeline;
the method for cooling end in step 806 is as follows: the low temperature liquid hydrocarbon flow regulating valve 313 is closed to stop the low temperature liquid hydrocarbon from entering the inside of the inner tank 301 along the cooling line.
Of course, in the adjustment process in the above step, the adjustment of the opening degree of the low-temperature liquid hydrocarbon flow rate adjustment valve 313 is also accompanied, and by this adjustment, the input flow rate of the low-temperature liquid hydrocarbon can be controlled, and the cooling rate of the cooling line and the inner tank can be controlled.
It can be seen that the present invention has the following advantages:
(1) in the invention, after low-temperature liquid hydrocarbon carried by a low-temperature liquid hydrocarbon transport ship sequentially flows through a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe and a cooling straight pipe, the low-temperature liquid hydrocarbon enters a low-temperature liquid hydrocarbon dispersion pipe from the joint of the cooling straight pipe and the low-temperature liquid hydrocarbon dispersion pipe at the central point of an edge ring pipe, the low-temperature liquid hydrocarbon enters the edge ring pipe after being dispersed by the low-temperature liquid hydrocarbon dispersion pipe, then flows out from openings uniformly distributed at intervals at the lower part of the edge ring pipe and is sprayed and atomized by nozzles connected to the openings to be injected in all directions, and the low-temperature liquid hydrocarbon dispersion pipe passes through the central point of the edge ring pipe, so the low-temperature liquid hydrocarbon dispersion pipe is symmetrically distributed relative to the edge ring pipe, therefore, the low-temperature liquid hydrocarbon dispersion pipe has uniform dispersion effect on the low-temperature liquid hydrocarbon, namely, the, this allows the same flow of cryogenic liquid hydrocarbon to exit each opening in the edge collar. In addition, because the nozzle which has the function of spraying and atomizing the low-temperature liquid hydrocarbon is arranged at the opening, the sprayed and atomized low-temperature liquid hydrocarbon can be contacted with any point of the inner tank to be cooled no matter the low-temperature liquid hydrocarbon is gasified into gaseous hydrocarbon and gradually descends towards the bottom of the inner tank or falls down towards the bottom of the inner tank in the form of liquid drops after being injected in all directions, namely any point on the inner tank can be contacted with the low-temperature liquid hydrocarbon to be cooled. In conclusion, the invention overcomes the two problems in the prior art, and ensures that the cooling speed of each point in the inner tank is uniform, thereby ensuring that the cooling speed of the low-temperature liquid hydrocarbon storage tank is uniform.
(2) Because the invention can ensure that the cooling speed of each point in the inner tank is uniform, compared with the prior art, the invention has the advantage that the cooling speed is greatly improved.
(3) The invention can ensure the safe and reliable cooling of the low-temperature liquid hydrocarbon storage tank by combining an automatic control system with a manual alarm control mode.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (23)
1. A cooling system for a cryogenic liquid hydrocarbon storage tank, the cryogenic liquid hydrocarbon storage tank comprising: the inner tank is positioned inside the outer tank; the suspended ceiling of the inner tank is connected with the vault of the outer tank through a suspension rod; a heat insulating material is filled between the inner surface of the outer tank and the outer surface of the inner tank; a nitrogen purging pipe penetrates through the vault of the outer tank to enter a space between the inside of the outer tank and the outside of the inner tank, and a nitrogen purging switch valve is installed on the nitrogen purging pipe; an emptying pipeline with one end communicated with the atmosphere and the other end communicated with the gas phase space inside the outer tank by penetrating through the vault of the outer tank; the opening degree of the emptying valve is adjustable and is positioned on the emptying pipeline; characterized in that the system comprises: a cryogenic liquid hydrocarbon carrier vessel for loading the cryogenic liquid hydrocarbon; a ship unloading arm connected with the low-temperature liquid hydrocarbon output pipe of the low-temperature liquid hydrocarbon transport ship; a low-temperature liquid hydrocarbon output main pipe connected with the output end of the ship unloading arm to output the low-temperature liquid hydrocarbon; the cooling straight pipe is connected with the low-temperature liquid hydrocarbon output main pipe, sequentially penetrates through the vault of the outer tank, the heat insulating material and the suspended ceiling of the inner tank, and enters the inner tank; the cooling ring pipe is positioned in a horizontal plane in the inner tank;
the cooling ring pipe comprises an edge ring pipe and a low-temperature liquid hydrocarbon dispersion pipe which penetrates through the center point of the edge ring pipe and has a dispersion effect on low-temperature liquid hydrocarbon; the edge ring pipe is communicated with the low-temperature liquid hydrocarbon dispersion pipe, and the low-temperature liquid hydrocarbon dispersion pipe is communicated with the cooling straight pipe at the central point of the edge ring pipe;
the lower part of the edge ring pipe is provided with openings which are uniformly distributed at intervals, and each opening is connected with a hollow nozzle which has the functions of spraying and atomizing the flowing low-temperature liquid hydrocarbon.
2. The system of claim 1, wherein adjacent two of said openings are staggered toward a center point of said edge collar and away from a center point of said edge collar.
3. The system of claim 2, wherein the nozzle has a central axis, and the central axis is angled downward from a vertically downward direction by a downward angle relative to the central axis of the nozzle; then
The central axis of a nozzle connected with an opening far away from the central point of the edge ring pipe is downwards far away from the vertical line of the central point, and the downward deflection angle of the central axis of the nozzle is between 30 and 60 degrees;
the central axis of the nozzle connected to the opening near the center point of the edge collar is directed downwards towards the vertical line of the center point, and the downward deflection angle of the central axis of the nozzle is between 30 and 60 degrees.
4. The system of claim 1, 2 or 3, wherein the nozzle comprises a butt opening portion, a connection portion, a low temperature liquid hydrocarbon spraying and atomizing portion, which are connected in series; wherein,
the butt joint opening part is a hollow pipeline which is connected to an opening on the edge ring pipe and communicated with the inside of the edge ring pipe;
the connecting part is a hollow pipeline communicated with the butt joint opening part;
the low-temperature liquid hydrocarbon spraying and atomizing part is a spiral cone with gradually reduced spiral radius.
5. The system of claim 1, further comprising a low temperature liquid hydrocarbon flow regulating valve with controllable opening degree on the cooling straight pipe and a flow meter capable of indicating flow.
6. The system of claim 1, further comprising a cryogenic liquid hydrocarbon input pipe connected to the cryogenic liquid hydrocarbon output header, passing sequentially through the dome of the outer tank, insulation, and the ceiling of the inner tank into the interior of the inner tank.
7. The system of claim 6, further comprising a draft tube located inside the inner vessel with an open inlet opposite the output end of the cryogenic liquid hydrocarbon input tube.
8. The system of claim 6 or 7, further comprising a controllable on-off low temperature liquid hydrocarbon input on-off valve on the low temperature liquid hydrocarbon input.
9. The system of claim 1, further comprising a gaseous hydrocarbon output pipe having one end communicating with the gas phase space on the cryogenic liquid hydrocarbon carrier vessel and the other end sequentially passing through the dome of the outer tank, the insulation material and the ceiling of the inner tank into the interior of the inner tank and communicating with the gas phase space inside the inner tank.
10. The system of claim 9, further comprising a gaseous hydrocarbon output on-off valve mounted on the gaseous hydrocarbon output conduit and controllable in on-off state.
11. The system of claim 1, wherein the inner vessel is a hollow cylindrical flat bottomed cup-shaped vessel with a circular ceiling;
temperature sensors are uniformly distributed on more than one concentric circle which takes the circle center as the circle center on the inner bottom surface of the inner tank;
temperature sensors are distributed at different heights on the inner side wall of the inner tank;
temperature sensors are uniformly distributed on more than one concentric circle which takes the circle center as the circle center on the upper bottom surface of the suspended ceiling;
temperature sensor on the interior bottom surface of inner tank and the inside wall, temperature sensor on the last bottom surface of furred ceiling all links to each other with temperature indicator.
12. The system of claim 11, further comprising temperature indicating alarms coupled to the temperature sensors on the inner bottom and inner side walls of the inner tank and the temperature sensor on the upper bottom surface of the ceiling.
13. The system of claim 1, further comprising an air pressure indication alarm that detects, indicates air pressure inside the inner vessel, and alarms when the air pressure exceeds a standard.
14. The system of claim 1, further comprising a gas outlet pipe communicating with the gas phase space inside the inner vessel, passing through the ceiling of the inner vessel, the insulation material, the dome of the outer vessel in sequence, and connecting to a flare system; and a safety valve with certain take-off pressure is arranged on the gas output pipe.
15. The system of claim 1, further comprising a nitrogen concentration sampling detector that detects a nitrogen concentration inside the inner vessel.
16. A method of cooling a cryogenic liquid hydrocarbon storage tank, the method being based on the cryogenic liquid hydrocarbon storage tank cooling system of claim 1; the system is characterized in that a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe, a cooling straight pipe and a cooling ring pipe of the low-temperature liquid hydrocarbon transport ship form a cooling pipeline; the method comprises the following steps:
step 1: the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship reaches the nozzle along the cooling pipeline, and the outflowing low-temperature liquid hydrocarbon is sprayed and atomized by the nozzle to diffuse into the inner tank;
step 2: judging whether the temperature drop temperature difference condition is satisfied, if not, stopping the low-temperature liquid hydrocarbon from entering the inner tank along the cooling pipeline until the temperature drop temperature difference condition is satisfied; wherein the temperature drop difference condition comprises: the temperature drop speed of any point on the inner bottom surface and the inner side wall of the inner tank and the upper bottom surface of the suspended ceiling is not more than 3 ℃/hour, and the temperature difference between any two points is not more than 30 ℃;
and step 3: judging whether the temperature of any point on the inner bottom surface of the inner tank is not higher than a set temperature, if so, executing the step 4, otherwise, executing the step 1;
and 4, step 4: and continuing to make the low-temperature liquid hydrocarbon reach the nozzle along the cooling pipeline and enter the inner tank under the spraying and atomizing of the nozzle until the height of the low-temperature liquid hydrocarbon in the inner tank reaches a height set value, and finishing the cooling.
17. The method of claim 16, wherein prior to step 1, the method further comprises:
step 01-1: opening the nitrogen purging switch valve to allow nitrogen to enter a space between the inside of the outer tank and the outside of the inner tank through the nitrogen purging pipe to replace air in the space; simultaneously opening a vent valve on the vent pipeline to discharge the replaced air to the external atmosphere;
step 02-1: and under the condition that the oxygen and water vapor contents of the space between the inside of the outer tank and the outside of the inner tank meet the specification requirement and the nitrogen pressure is greater than the atmospheric pressure outside the outer tank, closing the nitrogen purging switch valve and the emptying valve.
18. The method of claim 16, wherein the cooling system further comprises: a nitrogen gas replacement pipe which sequentially penetrates through the vault of the outer tank, the heat insulation material and the suspended ceiling of the inner tank to enter the inner tank so as to provide nitrogen gas to the inner tank; the nitrogen displacement switch valve is arranged on the nitrogen displacement pipe and can be controlled in switching state; before said step 1, the method further comprises:
step 01-2: opening the nitrogen replacement switch valve to enable nitrogen to enter the inner tank along the nitrogen replacement pipe so as to replace air in the inner tank;
step 02-2: and closing the nitrogen replacement switch valve under the condition that the oxygen and water vapor contents in the inner tank meet the standard requirements.
19. The method of claim 18, wherein the cooling system further comprises: the low-temperature liquid hydrocarbon input pipe is connected with the low-temperature liquid hydrocarbon output main pipe, sequentially penetrates through the vault of the outer tank, the heat insulation material and the suspended ceiling of the inner tank, and enters the inner tank; the low-temperature liquid hydrocarbon input switch valve is positioned on the low-temperature liquid hydrocarbon input pipe and can be controlled in switch state; then after said step 02-2, before said step 1, the method further comprises:
step 03-2: opening the low-temperature liquid hydrocarbon input switch valve to enable gaseous hydrocarbon on the low-temperature liquid hydrocarbon transport ship to enter the inner tank along a low-temperature liquid hydrocarbon output pipe, a ship unloading arm, a low-temperature liquid hydrocarbon output main pipe and a low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship;
step 04-2: and when the temperatures of the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship all reach the standard requirements, closing the low-temperature liquid hydrocarbon input switch valve.
20. The method of claim 19, wherein the cooling system further comprises a draft tube located inside the inner vessel with an open inlet opposite the output end of the cryogenic liquid hydrocarbon input tube; then after the step 4, a step 5 is further included: opening the low-temperature liquid hydrocarbon input switch valve, enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship to sequentially flow into the drainage tube along the low-temperature liquid hydrocarbon output pipe, the ship unloading arm, the low-temperature liquid hydrocarbon output main pipe and the low-temperature liquid hydrocarbon input pipe of the low-temperature liquid hydrocarbon transport ship, and enter the inner tank along the drainage tube until the transportation stop condition is met, and closing the low-temperature liquid hydrocarbon input switch valve; wherein the output stopping condition is as follows: the total amount of the low-temperature liquid hydrocarbon inside the inner tank reaches the rated volume of the inner tank, and/or the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transport ship is completely output.
21. The method of claim 19 or 20, wherein the cooling system further comprises: a combustible gas discharge pipe communicated with the gas phase space in the inner tank, sequentially penetrating through the suspended ceiling of the inner tank, the heat insulating material and the vault of the outer tank and connected with a torch system; the combustible gas discharge pipe is provided with a combustible gas discharge switch valve with controllable switch state; said step 03-2 further comprises: opening the combustible gas discharge switch valve to discharge the mixed gas of gaseous hydrocarbon and nitrogen in the inner tank along the combustible gas discharge pipe and burn the mixed gas by the torch system;
in the step 1, after the gaseous hydrocarbon obtained by gasifying the low-temperature liquid hydrocarbon diffused into the inner tank displaces the nitrogen gas in the inner tank, and the nitrogen gas content in the inner tank meets the specification, the step 1 further includes a step 11: and closing the combustible gas discharge switch valve.
22. The method of claim 21, wherein the cooling system further comprises a gaseous hydrocarbon output line and a controllable on-off gaseous hydrocarbon output on-off valve attached to the gaseous hydrocarbon output line; one end of the gaseous hydrocarbon output pipe is communicated with the gas phase space on the low-temperature liquid hydrocarbon transport ship, and the other end of the gaseous hydrocarbon output pipe sequentially penetrates through the vault of the outer tank, the heat insulating material and the suspended ceiling of the inner tank to enter the inner tank and is communicated with the gas phase space in the inner tank; then after said step 11 the method further comprises: and opening the gaseous hydrocarbon output switch valve to enable the gaseous hydrocarbon in the inner tank to enter the gas phase space on the low-temperature liquid hydrocarbon transport ship along the gaseous hydrocarbon output pipe.
23. The method of claim 16, wherein the cooling system further comprises a controllable opening cryogenic liquid hydrocarbon flow regulating valve located on the cooling straight pipe; then
The method for enabling the low-temperature liquid hydrocarbon on the low-temperature liquid hydrocarbon transportation ship to reach the nozzle along the cooling pipeline in the step 1 is as follows: opening the low temperature liquid hydrocarbon flow regulating valve to enable the low temperature liquid hydrocarbon on the low temperature liquid hydrocarbon carrier to reach the nozzle along the cooling pipeline;
the method for stopping the low-temperature liquid hydrocarbon from entering the inner tank along the cooling pipeline in the step 2 comprises the following steps: closing the low temperature liquid hydrocarbon flow regulating valve, stopping the low temperature liquid hydrocarbon from entering the inner tank interior along the cooling line;
the method for finishing cooling in the step 4 comprises the following steps: closing the low temperature liquid hydrocarbon flow regulating valve and stopping the low temperature liquid hydrocarbon from entering the inner tank along the cooling line.
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| CN201110171863A CN102261559A (en) | 2011-06-23 | 2011-06-23 | Cooling system and method for low-temperature liquid hydrocarbon storage tank |
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| CN201110171863A CN102261559A (en) | 2011-06-23 | 2011-06-23 | Cooling system and method for low-temperature liquid hydrocarbon storage tank |
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| CN103234114A (en) * | 2013-03-07 | 2013-08-07 | 西安交通大学 | Spray-type active cooling device |
| CN103343877A (en) * | 2013-07-26 | 2013-10-09 | 武汉钢铁(集团)公司 | Method and system for pre-cooling ethylene storage tank by low temperature nitrogen |
| CN104019014A (en) * | 2014-06-24 | 2014-09-03 | 安庆市江城冶金机械有限公司 | Energy tank and working method thereof |
| CN104482404A (en) * | 2014-10-28 | 2015-04-01 | 广东珠海金湾液化天然气有限公司 | Low-temperature ultra-large-type liquefied natural gas storage tank pre-cooling technology |
| CN104555163A (en) * | 2014-12-26 | 2015-04-29 | 河南神马尼龙化工有限责任公司 | Nylon 66 saline solution storing device and method |
| CN106369269A (en) * | 2016-08-30 | 2017-02-01 | 华陆工程科技有限责任公司 | Drying and replacing system and method of low-temperature storage tank |
| CN109404715A (en) * | 2018-10-29 | 2019-03-01 | 四川美丰化工股份有限公司 | A kind of large size LNG tank and its forecooling method |
| CN110857749A (en) * | 2018-08-23 | 2020-03-03 | 张家港中集圣达因低温装备有限公司 | Storage tank and precooling system thereof |
| CN111356873A (en) * | 2017-11-16 | 2020-06-30 | 气体运输技术公司 | Device for inerting a liquefied gas storage tank of a ship for transporting liquefied gas |
| CN114278859A (en) * | 2021-10-21 | 2022-04-05 | 海洋石油工程股份有限公司 | Vertical film type low-temperature normal-pressure liquid hydrogen storage tank |
| CN114688447A (en) * | 2020-12-29 | 2022-07-01 | 连云港石化有限公司 | Receiving system of long-distance large-diameter pipeline and start-up method thereof |
| WO2023182364A1 (en) * | 2022-03-23 | 2023-09-28 | 川崎重工業株式会社 | Methods for cooling down and warming up liquefied gas storage tank |
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|---|---|---|---|---|
| CN103234114A (en) * | 2013-03-07 | 2013-08-07 | 西安交通大学 | Spray-type active cooling device |
| CN103343877A (en) * | 2013-07-26 | 2013-10-09 | 武汉钢铁(集团)公司 | Method and system for pre-cooling ethylene storage tank by low temperature nitrogen |
| CN103343877B (en) * | 2013-07-26 | 2014-12-10 | 武汉钢铁(集团)公司 | Method and system for pre-cooling ethylene storage tank by low temperature nitrogen |
| CN104019014A (en) * | 2014-06-24 | 2014-09-03 | 安庆市江城冶金机械有限公司 | Energy tank and working method thereof |
| CN104482404A (en) * | 2014-10-28 | 2015-04-01 | 广东珠海金湾液化天然气有限公司 | Low-temperature ultra-large-type liquefied natural gas storage tank pre-cooling technology |
| CN104482404B (en) * | 2014-10-28 | 2016-04-13 | 广东珠海金湾液化天然气有限公司 | The precooling technique of low temperature super sized type liquefied natural gas (LNG) tank |
| CN104555163A (en) * | 2014-12-26 | 2015-04-29 | 河南神马尼龙化工有限责任公司 | Nylon 66 saline solution storing device and method |
| CN106369269A (en) * | 2016-08-30 | 2017-02-01 | 华陆工程科技有限责任公司 | Drying and replacing system and method of low-temperature storage tank |
| CN111356873B (en) * | 2017-11-16 | 2022-06-21 | 气体运输技术公司 | Device for inerting a liquefied gas storage tank of a ship for transporting liquefied gas |
| CN111356873A (en) * | 2017-11-16 | 2020-06-30 | 气体运输技术公司 | Device for inerting a liquefied gas storage tank of a ship for transporting liquefied gas |
| CN110857749A (en) * | 2018-08-23 | 2020-03-03 | 张家港中集圣达因低温装备有限公司 | Storage tank and precooling system thereof |
| CN109404715A (en) * | 2018-10-29 | 2019-03-01 | 四川美丰化工股份有限公司 | A kind of large size LNG tank and its forecooling method |
| CN114688447A (en) * | 2020-12-29 | 2022-07-01 | 连云港石化有限公司 | Receiving system of long-distance large-diameter pipeline and start-up method thereof |
| CN114688447B (en) * | 2020-12-29 | 2024-06-04 | 连云港石化有限公司 | Receiving system of long-distance large-diameter pipeline and starting method thereof |
| CN114278859A (en) * | 2021-10-21 | 2022-04-05 | 海洋石油工程股份有限公司 | Vertical film type low-temperature normal-pressure liquid hydrogen storage tank |
| WO2023182364A1 (en) * | 2022-03-23 | 2023-09-28 | 川崎重工業株式会社 | Methods for cooling down and warming up liquefied gas storage tank |
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Application publication date: 20111130 |