JP6515482B2 - Vaporization equipment and method for vaporizing low temperature liquefied gas - Google Patents

Description

  The present invention relates to a vaporization facility and a method for vaporization of low temperature liquefied gas.

  For example, as shown in Patent Document 1, a LNG (Liquefied Natural Gas) base is equipped with a vaporizer for vaporizing LNG, which is a low-temperature liquefied gas, by heat exchange with seawater or the like. A plurality of such vaporizers are generally provided as necessary. Further, at the LNG terminal, a pump for pumping out the LNG from the storage tank to the vaporizer is installed, and generally, a plurality of such pumps are provided.

  In such an LNG terminal, the number of operating pumps is determined according to the amount of vaporization, and the number of operating vaporizers is set based on the number of operating pumps. For this reason, when the flow rate paid out by one pump and the capacity of one vaporizer correspond to each other, the vaporizers are operated by the number of operated pumps.

JP, 2012-31980, A

  By the way, if the pump in operation stops urgently for some reason, since the liquid feeding from the said pump will be stopped, the supply pressure to the vaporizer in operation will fall. At this time, the degree of opening of the control valve provided upstream of the vaporizer is increased in order to secure the intake amount of LNG in the vaporizer.

  However, at the LNG terminal, when one of the pumps has an emergency stop, the stopped pump is operated alternatively, and the delivery amount of LNG is recovered in as short time as possible. For this reason, when the supply pressure to the vaporizer is rapidly recovered by the alternative operation of the pump, the control of the control valve can not catch up, and a large amount of LNG flows into the vaporizer through the control valve whose opening degree is large. As a result, the flow rate of LNG flowing into the vaporizer may exceed the rated flow rate of the vaporizer.

  The present invention has been made in view of the above-mentioned problems, and in a vaporization facility equipped with a plurality of pumps and a plurality of vaporizers and a vaporization method for low temperature liquefied gas, the flow rate of the low temperature liquefied gas supplied to the vaporizer is The purpose is to prevent excess.

  The present invention adopts the following configuration as means for solving the above-mentioned problems.

  According to a first aspect of the present invention, a plurality of pumps for pumping low temperature liquefied gas, a plurality of vaporizers for vaporizing the low temperature liquefied gas pumped by one or more of the pumps, and the respective vaporizers And a control valve for adjusting the flow rate of the low-temperature liquefied gas to the vaporizer, the vaporization facility comprising: A configuration is adopted in which a control device is provided to limit the maximum opening degree of the control valve provided in the operating vaporizer regardless of the supply pressure of the low temperature liquefied gas to the vaporizer.

  A second aspect of the invention is the control valve according to the first aspect of the invention, in the case where at least one of the plurality of pumps is operated and the pump in operation is urgently stopped. Adopt a configuration that limits the maximum opening.

  According to a third invention, in the first or second invention, at least one of the stopped vaporizers is in a standby state capable of transitioning to a state of receiving the supply of the low-temperature liquefied gas. The control device is configured to maintain the opening degree of the control valve provided in the standby vaporizer while limiting the maximum opening degree of the control valve provided in the operating vaporizer. To adopt.

  A fourth aspect of the present invention is a method for vaporizing low temperature liquefied gas, wherein the flow rate of low temperature liquefied gas pumped by one or more pumps to the vaporizer is controlled by a control valve, When the pump has an emergency stop, regardless of the supply pressure of the low temperature liquefied gas to the vaporizer for a predetermined period, the maximum opening degree of the control valve provided to the vaporizer in operation is limited. Adopt the configuration.

  According to the present invention, the maximum opening degree of the control valve provided to the carburetor in operation is limited even when the pump in operation has an emergency stop. For this reason, when the pump at the time of stop is operated, it is possible to regulate the flow rate of the low-temperature liquefied gas flowing into the vaporizer. Therefore, according to the present invention, it is possible to prevent the flow rate of the low temperature liquefied gas supplied to the vaporizer from becoming excessive in the vaporization facility and the low temperature liquefied gas vaporization method provided with the plurality of pumps and the plurality of vaporizers. Is possible.

It is a schematic diagram which shows schematic structure of the vaporization installation in one Embodiment of this invention. In the vaporization installation in one embodiment of the present invention, it is a flow chart for explaining the operation when only one of a plurality of pumps is operated, and also when this one is urgently stopped.

  Hereinafter, with reference to the drawings, an embodiment of a vaporization facility and a method for vaporization of low-temperature liquefied gas according to the present invention will be described. In the following drawings, the scale of each member is appropriately changed in order to make each member have a recognizable size.

  FIG. 1 is a schematic view showing a schematic configuration of a vaporization facility 1 of the present embodiment. As shown to this figure, the vaporization installation 1 of this embodiment is equipped with the pump 2, the vaporizer 3, the shut-off valve 4, the flow control valve 5 (control valve), and the control apparatus 6. As shown in FIG.

  The pump 2 pumps LNG (low temperature liquefied gas) stored in a storage tank (not shown) toward the vaporizer 3. In the vaporization installation 1 of the present embodiment, as shown in FIG. 1, four pumps (a pump 2a, a pump 2b, a pump 2c and a pump 2d) are provided. The number of pumps 2 is an example, and may be more or less.

  The vaporizer 3 vaporizes the LNG supplied from the pump 2 by heat exchange with seawater or the like. In the vaporization facility 1 of the present embodiment, as shown in FIG. 1, four vaporizers (vaporizer 3a, vaporizer 3b, vaporizer 3c and vaporizer 3d) are provided. The processing capacity of each vaporizer 3 is set to be able to process the LNG supplied from one pump 2. The number of vaporizers 3 is an example, and may be more or less. Moreover, the processing capacity of the vaporizer 3 can also be changed.

  The shutoff valve 4 is disposed upstream of the vaporizer 3. The shutoff valve 4 opens and closes a pipe connected to the vaporizer 3 under the control of the control device 6. Such a shutoff valve 4 is provided for each vaporizer 3. That is, as shown in FIG. 1, the shutoff valve 4a is provided for the vaporizer 3a, the shutoff valve 4b is provided for the vaporizer 3b, and the shutoff valve 4c is provided for the vaporizer 3c, A shutoff valve 4d is provided for the vaporizer 3d. These shutoff valves 4 are fully opened when the corresponding vaporizer 3 is in operation, and are fully closed when the corresponding vaporizer 3 is in operation. That is, for example, when only the vaporizer 3a is in operation, only the shutoff valve 4a is fully opened, and the other shutoff valves 4 (the shutoff valve 4b, the shutoff valve 4c and the shutoff valve 4d) are fully closed.

  The flow control valve 5 is disposed between the vaporizer 3 and the shutoff valve 4. The flow control valve 5 is provided for each vaporizer 3. That is, as shown in FIG. 1, the flow control valve 5a is provided for the vaporizer 3a, the flow control valve 5b is provided for the vaporizer 3b, and the flow control valve 5c for the vaporizer 3c. Is provided, and a flow control valve 5d is provided for the vaporizer 3d. These flow rate control valves 5 are adjusted in opening under the control of the control device 6 when the corresponding vaporizer 3 is in operation, whereby the flow rate of the LNG supplied to the vaporizer 3 Adjust the On the other hand, the flow control valve 5 is in a slightly open state when the corresponding vaporizer 3 is at rest. That is, for example, when only the vaporizer 3a is in operation, only the opening degree of the flow control valve 5a is adjusted, and the other flow control valves 5 (flow control valve 5b, flow control valve 5c, and flow control valve 5d) Is slightly open.

  The control device 6 controls the entire vaporization equipment 1 of the present embodiment. Such a control device 6 is electrically connected to each of the shutoff valve 4 and the flow control valve 5 as shown in FIG. 1 in the vaporization facility 1 of the present embodiment, and these shutoff valves 4 And the open / close state of the flow control valve 5 is controlled. Further, the control device 6 receives the state of the pump 2 and the supply pressure of LNG to the vaporizer 3 by a sensor or the like (not shown).

  In the vaporization facility 1 of the present embodiment, only one of the plurality of pumps 2 is operated in such a control device 6, and when this one is urgently stopped, it is in operation during a predetermined period. The maximum opening degree of the flow control valve 5 provided in the carburetor 3 is limited. That is, for example, in a state where only the pump 2a is operated among the plurality of pumps 2 and only the vaporizer 3a among the plurality of vaporizers 3 is operated, the control device 6 performs an emergency stop of the pump 2a. The maximum opening degree of the flow control valve 5a provided corresponding to the vaporizer 3a is limited until a predetermined time period has elapsed.

  Here, a period (predetermined period) in which the maximum opening of the flow control valve 5 is restricted is hereinafter referred to as an opening restriction time. Further, the maximum opening degree of the flow control valve 5 when the opening degree is restricted in the opening degree regulating time is referred to as a restriction maximum opening degree.

  The opening regulation time is determined according to the period from the emergency stop of one pump 2 to the completion of the alternative start of the other pump 2 and is slightly longer than the period until the completion of the alternative start It is set. For this reason, based on the normal sequence, when the other pump 2 is activated alternatively, the maximum opening degree of the flow control valve 5 provided in the operating vaporizer 3a is limited to the limited maximum opening degree during that time Ru. Note that the opening degree regulation time may be set to be longer than the period until the alternative activation is completed, and is not limited to the case where it is slightly longer than the period until the alternative activation is completed.

  When the supply pressure of LNG to the vaporizer 3 is a normal pressure (supply pressure when one pump 2 is normally operated), the flow rate to the vaporizer 3 is equal to or higher than the rated flow rate. This is the largest degree of opening required to supply LNG. That is, while the maximum opening degree of the flow control valve 5 is limited to the maximum opening degree, even if the supply pressure to the vaporizer 3 is recovered rapidly, the flow rate to the vaporizer 3 is higher than the rated flow rate. Supply of LNG at a flow rate is prevented.

  Furthermore, the control device 6 is provided to the operating vaporizer 3 when at least one of the stopped vaporizers 3 is in a standby state (standby state) capable of shifting to a state of receiving the supply of LNG. While limiting the maximum opening degree of the flow control valve 5 (that is, the opening degree regulation time), the opening degree of the flow control valve 5 provided on the standby vaporizer 3 is maintained. That is, for example, when the opening regulation time is reached when the vaporizer 3b is in standby, the control device 6 slightly opens the flow control valve 5b provided in the vaporizer 3b. maintain.

  Next, in the vaporization facility 1 of the present embodiment having such a configuration, only one of the plurality of pumps 2 is operated, and the operation when one of the plurality of pumps is urgently stopped (tripped) is the flowchart of FIG. Explain with reference to. In the following description of the operation, the subject of the operation is the control device 6.

  The control device 6 constantly monitors whether or not a trip (emergency stop of the pump 2) has occurred during the normal operation in which one pump 2 is operated (step S1). Then, when the trip has not occurred, the control device 6 maintains the normal operation (step S2). On the other hand, when a trip has occurred, the control device 6 confirms whether the vaporizer 3 in the standby state is absent (step S3). When the vaporizer 3 in the standby state is present, the flow control valve 5 provided in the vaporizer 3 is maintained in a slightly open state, whereby the vaporizer 3 is maintained in the standby state (step S4). ).

  After completion of step S4, when there is no carburetor 3 in standby in step S3, the control device 6 determines whether the opening regulation time has elapsed (step S5). Then, when the opening regulation time has not elapsed, the maximum opening of the flow control valve 5 provided in the operating carburetor 3a is regulated with the restriction maximum opening (step S6). And if opening regulation time passes, the regulation concerned will be canceled (Step S7).

  When the regulation is released in this manner, the flow control valve 5 provided in the operating vaporizer 3 is adjusted in degree of opening in accordance with the supply pressure of LNG to the vaporizer 3. Therefore, for example, when the alternative operation of the other pump 2 is completed before the opening regulation time has elapsed, the supply pressure becomes the same as before the trip occurrence, so the opening degree of the flow control valve 5 Is basically the same as before the trip occurrence. On the other hand, when the alternative operation of the other pump 2 is not completed due to an emergency such as a failure, the supply pressure is in a reduced state, so the amount of supply of LNG to the vaporizer 3 during operation is secured as much as possible Therefore, the opening degree of the flow control valve 5 is expanded beyond the limit maximum opening degree.

  According to the vaporization facility 1 of the present embodiment as described above, even if the pump 2 in operation is in an emergency stop, regardless of the supply pressure, the flow control valve 5 provided in the vaporizer 3 in operation Maximum opening is limited to the maximum opening. Therefore, it is possible to regulate the flow rate of the LNG flowing into the vaporizer 3 when the stopped pump 2 is operated alternatively. Therefore, according to the present embodiment, it is possible to prevent the flow rate of the LNG supplied to the vaporizer 3 from becoming excessive.

  Further, in the vaporization facility 1 of the present embodiment, the maximum opening of the flow control valve 5 is performed when only one of the plurality of pumps 2 is operated by the control device 6 and the pump 2 in operation is urgently stopped. Limited degree. When only one pump 2 is in operation, when the pump 2 is stopped, the supply pressure to the vaporizer 3 is significantly reduced. For this reason, the opening degree of the flow control valve 5 is most likely to be the largest, and it is easy for the excess flow of LNG to flow into the vaporizer 3 after the alternative operation. According to the present invention, it is possible to avoid the occurrence of a situation where LNG tends to flow more than the rated flow rate to such a vaporizer 3 most.

  Further, in the vaporization facility 1 of the present embodiment, the control device 6 is provided to the vaporizer 3 in operation when at least one of the stopped vaporizers 3 is in standby (standby). While limiting the maximum opening degree of the flow control valve 5 (during the opening restriction time), the opening degree of the flow control valve 5 provided on the carburetor 3 in the standby state is maintained. Therefore, the operation of the other vaporizer 3 can be started during the opening regulation time, and the supply pressure to the vaporizer 3 can be prevented from further decreasing.

  As mentioned above, although the suitable embodiment of the present invention was described referring to drawings, the present invention is not limited to the above-mentioned embodiment. The shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the above embodiment, when only one of the plurality of pumps 2 is operated and the pump 2 in operation is urgently stopped, the maximum opening of the flow control valve 5 provided in the vaporizer 3 in operation is The configuration for limiting the degree has been described. However, the present invention is not limited to this, and in the case where a plurality of pumps 2 are operated and any or all of the operating pumps are urgently stopped, the flow rate similarly provided to the operating vaporizer 3 The maximum opening degree of the control valve 5 may be limited.

  Moreover, in the said embodiment, the low temperature liquefied gas demonstrated the structure which is LNG. However, the present invention is not limited to this, and it is also possible to apply other low temperature liquefied gas to the vaporization facility.

  DESCRIPTION OF SYMBOLS 1 ... vaporization equipment, 2 ... pump, 2a ... pump, 2b ... pump, 2c ... pump, 2d ... pump, 3 ... vaporizer, 3a ... vaporizer, 3b ... vaporizer, 3c ... vaporizer, 3d ... vaporizer, 4 ... shut-off valve, 4a ... shut-off valve, 4b ... shut-off valve, 4c ... shut-off valve, 4d ... shut-off valve, 5 ... flow control valve (control valve), 5a ... flow control valve (control valve), 5b ... flow control valve (Control valve), 5c: Flow control valve (control valve), 5d: Flow control valve (control valve), 6: Control device

Claims (4)

A plurality of pumps for pumping low temperature liquefied gas, a plurality of vaporizers for vaporizing the low temperature liquefied gas pumped by one or more of the pumps, and provided for each of the vaporizers And a control valve for adjusting the flow rate of the low-temperature liquefied gas.
When one or more pumps in operation are in emergency stop, at least a period until alternative start of other pumps is completed, regardless of the supply pressure of the low temperature liquefied gas to the vaporizer, during operation. A vaporization facility comprising: a control device for limiting the maximum opening degree of the control valve provided in the vaporizer.   The control device restricts the maximum opening degree of the control valve when at least one of the plurality of pumps is operated and the pump in operation is urgently stopped. The vaporization installation of 1 statement.   When at least one of the stopped vaporizers is in a standby state capable of transitioning to a state of receiving the supply of the low-temperature liquefied gas, the control device controls the control provided to the vaporizer in operation. The vaporization installation according to claim 1 or 2, wherein the opening degree of the control valve provided in the standby vaporizer is maintained while limiting the maximum opening degree of the valve. A method of vaporizing a low temperature liquefied gas, wherein a flow rate of low temperature liquefied gas pumped by one or more pumps to a vaporizer is adjusted by a control valve,
When one or more pumps in operation are in emergency stop, at least a period until alternative start of other pumps is completed , regardless of the supply pressure of the low temperature liquefied gas to the vaporizer, during operation. A method of vaporizing a low-temperature liquefied gas, comprising limiting the maximum opening degree of the control valve provided in the vaporizer.

Images