CN204717340U - A kind of LNG Liquefied natural gas receiving station rock gas output system - Google Patents

Abstract

The invention discloses a natural gas output system of a liquefied natural gas receiving station. The system created by the present invention includes LNG receiving station, low-pressure submersible pump, high-pressure pump, gasifier, turbo expander and other equipment, wherein the high-pressure natural gas obtained by the gasifier is input into the turbo expander to perform expansion work; the high-pressure natural gas expands The work done at the time is input into the high-pressure pump through the device, and the expanded natural gas is output to the user. Due to the use of solar vaporizers, the system created by the invention has the characteristics of energy consumption; at the same time, due to its relatively simple structure, the system created by the invention can not only be widely used in water-deficient areas, but also be used in movable equipment to form skids. The installation equipment further expands the scope of application of the present invention to create the natural gas output system of the LPG receiving station.

Description

A natural gas output system of a liquefied natural gas receiving station

technical field

The invention relates to a low energy consumption natural gas output system of an LNG (liquefied natural gas) receiving station.

Background technique

The LNG receiving station generally refers to the LNG gasification plant built on the seashore in order to receive LNG transported by sea. It unloads, stores, and BOG gasifies the LNG transported by ocean-going transport ships, and then transports the LNG gasification to users and projects. wait.

In the existing LNG receiving station process, LNG is pressurized by a high-pressure pump, sent to a vaporizer for gasification and exported, and BOG is pressurized by a BOG compressor and then transported or sent to a recondenser for cooling. In the entire process, LNG High pressure pumps and BOG compressors account for a higher percentage of total energy consumption.

LNG is stored in the form of cryogenic liquid. When used as fuel, it must be in a gaseous state. At this time, a gasifier must be used. The gasification of LNG requires energy to convert low-temperature liquefied natural gas into a normal temperature gas, and corresponding heat must be provided. The source of heat can be obtained from ambient air and water, or by fuel combustion. The LNG gasifiers widely used at present are open frame gasifiers, submerged combustion gasifiers and intermediate medium gasifiers.

Open-frame gasifiers use seawater as a heat source and are often used in base-load LNG receiving terminals. It is composed of a group of aluminum alloy tubes with a star-shaped section inside and fins on the outside. The initial investment is high and the installation cost is high. It uses seawater. As the water temperature decreases, the gasification capacity decreases, and The energy consumption of seawater pumps is very high, and seawater also corrodes the base metal.

A submerged fired gasifier uses a burner that discharges gas directly into the water. Due to the need to continuously burn fuel gas, the cost is increased, it is not environmentally friendly, and the operating cost is relatively high.

Intermediate medium gasifier, which usually uses propane, butane or freon as the intermediate heat transfer fluid, it serves as the intermediate medium to exchange heat with seawater or other heat source fluids, and then the intermediate medium exchanges heat with LNG, but it needs to be selected The matching intermediate medium adds the shell of the intermediate medium and has a complex structure.

Contents of the invention

Aiming at the deficiencies of the prior art, the utility model provides a natural gas output system of a LNG receiving station with low energy consumption. The process energy consumption of the natural gas output system of the utility model is low, and the gasifier equipment has the advantages of simple structure, low maintenance operation cost and the like.

The technical solution adopted by the present invention to solve the technical problem is: adopting the principle that liquid pressurization is easier to gas pressurization, after the LNG high-pressure pump does more work, after being gasified by the gasifier, it enters the expander to do work, and drives the high-pressure pump.

The utility model provides a natural gas output system of an LNG receiving station, and the system includes:

At least one liquefied natural gas (LNG) storage tank, which is used to receive liquefied natural gas transported by ships or LNG tankers; gas (BOG) removal device from the storage tank, and removal device for removing pressurized liquefied natural gas from the storage tank;

A high-pressure pump, which is used to pressurize the low-pressure liquefied natural gas to a pressure higher than the output pressure of the pipeline network; the high-pressure pump includes a feed pipeline for feeding the low-pressure liquefied natural gas to the high-pressure pump, and a The pressurized liquefied natural gas is fed to the gasifier pipeline, and the device used to input the turbo expander to do work;

a gasifier for vaporizing high-pressure liquefied natural gas from a high-pressure pump into high-pressure natural gas; the gasifier includes a feed line for feeding the high-pressure liquefied natural gas from the high-pressure pump to the gasifier, and Pipeline for transporting the vaporized natural gas to the turboexpander;

a turboexpander for expanding high-pressure natural gas from the gasifier; said turboexpander including a feed line for feeding high-pressure natural gas from the gasifier to said turboexpander , the pipeline used to export the expanded natural gas, and the device used to output the work of the turbo expander;

A gas compressor, which is used to pressurize the boil-off gas from the LNG storage tank; the gas compressor includes a feed line for feeding the boil-off gas from the LNG storage tank to the gas compressor, for Pipeline for the output of compressed boil-off gas.

In the natural gas output system of the present utility model, it may also include a recondenser; it includes a feed pipeline for receiving the evaporated gas output from the gas compressor, and is used to feed the low-pressure liquefied natural gas output from the LNG storage tank to the Feed line to the recondenser, and removal device for output of the recondensed product (to a high pressure pump).

In the system of the present utility model, the gasifier is a solar gasifier; it includes a feed pipeline used to feed the liquefied natural gas pressurized by a high-pressure pump to the gasifier, and is used to gasify The removal line of the final high-pressure natural gas output (to the turbo expander).

Wherein, an LNG inlet flow controller is also provided on the feed pipeline used to feed the liquefied natural gas pressurized by the high-pressure pump to the gasifier, which is used to remove the gasified high-pressure natural gas (to the turbo expansion NG outlet flow controller is also set on the removal pipeline of machine).

Among them, the solar gasifier includes a closed, fixed volume, pressure-resistant tank with external solar panels, several spray devices, pressure sensors and liquid level sensors arranged inside the tank, and one side of the housing There is an LNG input port and an NG output port on the other side.

The solar gasifier includes a liquid level sensor for measuring the height of the liquid level, a control system, a pressure sensor for measuring the pressure inside the gasifier, a spray device for spraying the high-pressure liquefied natural gas, and a A solar heating device for heating a solar gasifier. Wherein the solar heating device is located on the outer surface of the tank body of the vaporizer.

In the system of the present invention, the work of the turbo expander is used to drive the LNG high-pressure pump.

In the natural gas output system of the present utility model, the removal device for removing boil-off gas (BOG) out of the LNG storage tank and the feeding pipeline for feeding the boil-off gas from the LNG storage tank to the gas compressor may be the same device. Similarly, the removal device used to remove the pressurized liquefied natural gas from the storage tank and the feeding pipeline for feeding the low-pressure liquefied natural gas to the high-pressure pump can also be the same device. The feeding pipeline for feeding the pressurized high-pressure LNG to the gasifier and the device for removing the high-pressure LNG after the pressurization of the high-pressure pump can also be the same device. Similarly, the device for inputting the work of the turboexpander into the high-pressure pump and the device for outputting the work of the turboexpander can also be the same device or a matching device.

Further, when the system of the present invention is working, the LNG in the LNG storage tank must be continuously input to ensure that the gasification amount of LNG in the gasifier is balanced with the output of NG, so as to maintain the pressure of the gasifier.

Further, the pressure sensor provided inside the gasifier can monitor the change of internal pressure, and the liquid level sensor can monitor the liquid level of LNG inside the gasifier.

In the utility model, the gasifier also includes a control system loop, the signal input end of the control system is respectively connected to the liquid level sensor of the gasifier and the pressure sensor of the gasifier, and the output of the control system loop The end is the flow control valve of the input port of high-pressure LNG and the flow control valve of the output port of NG. When the pressure increases and the LNG liquid level is too high, the input of LNG and the output of NG can be reduced, and when the pressure decreases and the liquid level is too low, the input of LNG and the output of NG can be increased.

In this utility model, unless otherwise specified, "LNG" refers to liquefied natural gas (liquefied gas), "BOG" refers to boil-off gas, "NG" refers to natural gas, and "vaporizer" is the same as "gasifier".

Based on the above-mentioned system, the working process of the natural gas output system of the LNG receiving station in the present invention is:

The LNG is pressurized by the low-pressure submersible pump in the LNG storage tank and then sent to the LNG high-pressure pump. The LNG is pressurized by the high-pressure pump to a pressure higher than the external delivery pressure. The LNG is sent into the solar gasifier by the high-pressure pump. The spray device is sprayed into the gasifier. At the beginning of operation, the input of LNG should be controlled within a certain range to ensure smooth gasification. LNG is continuously gasified. When the pressure generated by the gas reaches the external pressure, the natural gas starts to be exported, and at the same time, the continuous flow of LNG input, and keep the amount of gasification equal to the output of natural gas, so as to maintain a dynamic balance. The high-pressure natural gas is exported and enters the expander to do work. Then it is directly sent to the high-pressure external pipeline network for supply to users.

The work done by the expander is used to drive the LNG high-pressure pump.

The BOG volatilized in the storage tank of the LNG receiving station in the present invention is transported to the BOG compressor through the BOG gas transmission main pipe, and after pressurization, 1. Directly pressurized to the pressure required by the user of the external transportation pipeline network and directly exported. 2. After pressurized, send it to the recondenser for cooling.

Compared with the prior art, the natural gas output system of the liquefied natural gas receiving station of the utility model has the following advantageous effects.

1. The natural gas output system of the LNG receiving station of the present invention has a simple structure and low maintenance and operation costs in the later period.

2. Due to the adoption of a solar gasifier, the operating energy consumption of the system of the utility model is relatively low.

3. The LNG input port of the solar gasifier is equipped with several spraying devices, and the liquid flows downward evenly through the spraying devices of the tank body, so that the heating speed is rapid, and the pressurized LNG can be fully, quickly and stably gasification. That is, the system of the present invention also has the characteristics of fast gasification speed and stable natural gas output.

4. The gasifier uses solar energy as the basic heat medium, and does not need circulating water and intermediate cooling medium. Therefore, the system of the utility model can not only be widely used in water-deficient areas, but also be used in movable equipment to form skid-mounted equipment , further expanding the scope of application of the LPG receiving station natural gas output system of the present invention.

Description of drawings

Fig. 1 is a structural schematic diagram of a natural gas output system of the present invention.

Among them, 1-LNG storage tank, 2-low pressure submersible pump, 3-pipeline, 4-pipeline, 5-high pressure pump, 6-input/output device, 7-LNG input flow controller, 8-liquid level sensor, 9 -Control system, 10-pressure sensor, 11-gasifier LNG input pipeline, 12-spray device, 13-gasifier, 14-NG output flow controller, 15-NG output pipeline, 16-turbo expander , 17-pipeline, 18-gas compressor, 19-pipeline, 24-solar heating device.

Fig. 2 is another structural schematic diagram of the natural gas output system of the present invention.

Among them, 1-LNG storage tank, 2-low pressure submersible pump, 3-pipeline, 4-pipeline, 5-high pressure pump, 6-input/output device, 7-LNG input flow controller, 8-liquid level sensor, 9 -Control system, 10-pressure sensor, 11-gasifier LNG input pipeline, 12-spray device, 13-gasifier, 14-NG output flow controller, 15-NG output pipeline, 16-turbo expander , 17-pipeline, 18-gas compressor, 19-pipeline, 20-recondenser, 21-pipeline, 22-pipeline, 23-pipeline, 24-solar heating device.

Detailed ways

In order to describe the technical content, structural features, achieved goals and effects of the present invention in detail, the following describes in detail in conjunction with specific implementation methods and accompanying drawings.

Example 1

As shown in Fig. 1, a kind of LNG receiving station natural gas output system, described system comprises:

LNG storage tank 1, said LNG storage tank 1 includes a submersible pump 2 for pressurizing cryogenic liquefied natural gas, a pipeline 3 for removing boil-off gas (BOG) out of the storage tank, and a pipeline for Line 4 where LNG moves out of the storage tank.

A high-pressure pump 5, which is used to pressurize the low-pressure liquefied natural gas to a pressure higher than the output pressure of the pipeline network; the high-pressure pump 5 includes a feed line for feeding the low-pressure liquefied natural gas to the high-pressure pump, and the feed line is connected to the high-pressure pump The line used to remove the pressurized LNG from the storage tank is the same device), and the line 11 used to feed the pressurized LNG to the vaporizer, and the input used to enter the turboexpander for work /output device6.

Gasifier 13, which is used to vaporize the high-pressure liquefied natural gas from the high-pressure pump into high-pressure natural gas; the gasifier 13 includes a pipeline for feeding the high-pressure liquefied natural gas from the high-pressure pump to the gasifier 11 (the same line used to feed the pressurized LNG to the vaporizer), and line 15 to feed the vaporized natural gas to the turboexpander.

In the gasifier 13, an LNG input flow controller 7 is also provided on the pipeline 11 used to feed the pressurized liquefied natural gas into the gasifier, and is used to remove the gasified high-pressure natural gas (to A NG output flow controller 14 is also set on the pipeline 15 of the turboexpander).

The gasifier 13 is a solar gasifier, which includes a closed, fixed-volume, pressure-resistant tank with external solar panels. The gasifier 13 also includes a liquid level sensor 8 for measuring the liquid level, a control system 9, a pressure sensor 10 for measuring the pressure inside the gasifier, and a spraying device for spraying the high-pressure liquefied natural gas 12 and solar heating means 24 for heating the gasifier. Wherein the solar heating device is located on the outer surface of the tank body of the vaporizer. The liquid level sensor 8, the pressure sensor 10, the LNG input flow controller 7, and the NG output flow controller 14 are all connected with the control system 9.

The turbo expander 16 is used for expanding the high-pressure natural gas from the gasifier. The turboexpander includes a line 15 for feeding the high-pressure natural gas from the gasifier to the turboexpander (the same device used to feed the vaporized natural gas to the turboexpander), using The pipeline 17 used to output the expanded natural gas, and the input/output device 6 used to output the work of the turbo expander (the same device used to input the work of the turbo expander).

Gas compressor 18, which is used to pressurize the boil-off gas from the LNG storage tank. The gas compressor includes the pipeline 3 used to feed the boil-off gas from the LNG storage tank to the gas compressor (the same device as the pipeline that removes BOG from the LNG storage tank), and is used to output the compressed boil-off gas directly Line 19 of .

During operation, LNG is pressurized by the submersible pump and sent to the high-pressure pump, and the high-pressure pump is sent to the solar gasifier, and the solar gasifier does not output to the outside, and then the LNG is sprayed into the gasification slowly and stably through the spray device. In the gasifier, it is continuously vaporized under the heat of the outside world, and the generated gas is gathered in a closed, fixed-volume, pressure-resistant gasifier. With the continuous generation of gas, the pressure of the gasifier continues to increase. When The gasified gas is continuously gathered until the pressure of the gas in the gasifier reaches the rated pressure that the gasifier can withstand, and then it starts to be exported. The output per unit time is equal to the gasification of LNG entering the gasifier into NG per unit time. The amount, and keep this dynamic process unchanged, the tank is also equipped with a liquid level controller and a pressure controller, when the external environment changes, when the heat provided by the external solar energy is insufficient, the liquid level controller and the pressure controller After receiving the change of the signal, the signal is transmitted to the receiving end to control the LNG flow control valve on the LNG input port through the control circuit, so as to reduce the input of LNG and change the output of NG at the same time. When the heat provided by the outside is too much, the liquid The position controller and pressure controller receive the change of the signal, and transmit the signal to the receiving end of the controller through the control loop. The receiving end of the controller controls the LNG flow control valve on the LNG input port, increases the input amount of LNG, and controls the NG outlet at the same time Increase the output of natural gas. The natural gas is delivered to the expander, and the expansion works to push the LNG high-pressure pump, and then send it to the export pipeline network.

The BOG volatilized from the tank adopts the process of direct pressurization and output.

Example 2

Fig. 2 shows another low energy consumption LNG receiving station natural gas output system of the present invention. The basic structure of the natural gas output system shown in Figure 2 is the same as that of Embodiment 1 (Figure 1), except that the system also includes: a recondenser 20, which includes a pipeline for receiving the boil-off gas output from the gas compressor 19. A pipeline 21 for feeding the low-pressure liquefied natural gas output from the LNG storage tank to the recondenser, and a removal device (pipeline) 22 for outputting the recondensed product (to a high-pressure pump).

During operation, part of the LNG is pressurized by the submersible pump and sent to the recondenser. In the recondenser, BOG is cooled to LNG, mixed with the rest of the low-pressure LNG, and then sent to the high-pressure pump. The high-pressure pump is sent to the solar gasifier. The solar gasifier does not output to the outside first, and then the LNG is sprayed into the gasifier slowly and steadily through the spray device, so that it is continuously gasified under the heat of the outside world, and the generated gas gathers in a closed, fixed volume, In the pressure-resistant gasifier, with the continuous generation of gas, the pressure in the device continues to increase. When the gasified gas continues to accumulate to the end, the pressure of the gas in the gasifier reaches the rated pressure that the gasifier can withstand When the output is started, the output per unit time is equal to the amount of LNG gasified into NG entering the gasifier per unit time, and this dynamic process remains unchanged. The gasifier is also equipped with a liquid level controller and a pressure controller. When the external environment changes and the heat provided by the external solar energy is insufficient, the liquid level controller and pressure controller receive the signal change, and transmit the signal to the receiving end to control the LNG flow control valve on the LNG input port through the control loop. Reduce the input of LNG and change the output of NG at the same time. When the heat provided by the outside is too much, the liquid level controller and pressure controller will receive the signal change and transmit the signal to the controller receiving end through the control loop. The receiving end of the controller controls the LNG flow control valve on the LNG input port to increase the input volume of LNG, and at the same time controls the NG outlet to increase the output volume of natural gas. The natural gas is delivered to the expander, and the expansion works to push the LNG high-pressure pump, and then send it to the export pipeline network.

The BOG volatilized from the tank is output through the recondensation process.

Claims (10)

1. a LNG Liquefied natural gas receiving station rock gas output system, described system comprises:

Liquefied natural gas (LNG) tank, it is for receiving the LNG Liquefied natural gas of boats and ships or tank car conveying; Described liquefied natural gas (LNG) tank comprises the immersed pump for low-temperature liquefaction rock gas being carried out supercharging, for boil-off gas being shifted out the moving-out device of storage tank, with for the LNG Liquefied natural gas after supercharging being shifted out the moving-out device of storage tank;

High-pressure service pump, it is for being pressurized to the pressure higher compared with pipe network delivery pressure by low pressure liquefied natural gas; Described high-pressure service pump comprises the feeding line for low pressure liquefied natural gas being fed to this high-pressure service pump, and for the LNG Liquefied natural gas after supercharging being fed to the pipeline of vaporizer, and is used for inputting the device of turbo-expander acting;

Vaporizer, it is for being high-pressure natural gas by the high-pressure liquefaction natural gas vaporization from high-pressure service pump; Described vaporizer comprise for by the high-pressure liquefaction natural gas feed from high-pressure service pump to the feeding line of this vaporizer, and be used for the pipeline of the natural gas transport after by vaporization to turbo-expander;

Turbo-expander, it is for carrying out expansion work to the high-pressure natural gas from vaporizer; The described turbo-expander high-pressure natural gas comprised in the future autopneumatolysis device is fed to the feeding line of described turbo-expander, is used for the pipeline exported by the rock gas after expanding, and is used for the device that the acting of turbo-expander exported;

Gas compressor, it is for carrying out supercharging to the boil-off gas from liquefied natural gas (LNG) tank; Described gas compressor comprises the feeding line for the boil-off gas from liquefied natural gas (LNG) tank being fed to this gas compressor, be used for by compression after boil-off gas export pipeline.

2. according to system according to claim 1, it is characterized in that, described system also comprises after-condenser; It comprises the boil-off gas exported for receiver gases compressor feeding line, be fed to for the low pressure liquefied natural gas that liquefied natural gas (LNG) tank is exported described after-condenser feeding line and be used for the moving-out device of the output of condensed product again.

3. according to the system described in claim 1 or 2, it is characterized in that, being used for that feeding line that the LNG Liquefied natural gas after by high-pressure service pump supercharging is fed to described vaporizer also arranges LNG Liquefied natural gas input flow rate controller, shifting out on pipeline of being used for that the high-pressure natural gas after by gasification shifts out arrange rock gas output flow controller.

4. according to the system described in claim 1 or 2, it is characterized in that, described vaporizer is solar energy vaporizer, it comprise one close, the tank body of fixed volume, withstand voltage, peripheral hardware solar panels.

5. according to system according to claim 4, it is characterized in that, described vaporizer also comprising liquid level sensor for measuring liquid level height, control system, for measuring the pressure transducer of vaporizer internal pressure, being used for the spray equipment that sprays high-pressure liquefaction rock gas and the solar heat collector for heating vaporizer.

6. according to system according to claim 3, it is characterized in that, the described moving-out device for boil-off gas being shifted out liquefied natural gas (LNG) tank is same device with the feeding line boil-off gas from liquefied natural gas (LNG) tank being fed to gas compressor.

7. according to system according to claim 3, it is characterized in that, the described moving-out device for the LNG Liquefied natural gas after supercharging being shifted out storage tank is same device with feeding line low pressure liquefied natural gas being fed to high-pressure service pump.

8., according to system according to claim 3, it is characterized in that, described for being same device to the feeding line of vaporizer with being used for the high-pressure liquefaction rock gas moving-out device after by high-pressure service pump supercharging by the high-pressure liquefaction natural gas feed after supercharging.

9., according to system according to claim 3, it is characterized in that, the described device with inputting turbo-expander acting in dealing high-pressure service pump with and the device that is used for the acting of turbo-expander to export also be same device or adapting device.

10. according to system according to claim 5, it is characterized in that, signal input part connecting fluid level sensor and the pressure transducer respectively of described control system, the output terminal of described control system is the input flow rate control valve of high-pressure liquefaction rock gas and the output flow control valve of rock gas.