TW201638540A - Apparatus and method for supplying liquid fuel gas - Google Patents

Abstract

An apparatus and a method for supplying a liquid fuel gas having a high energy efficiency, which is efficiently using the coldness of the LNG and being capable of ensuring a supply amount of the liquid fuel gas according to the fluctuation in the composition or the demanded amount of the LNG serving as a source material with little need of the external energy, wherein - the LNG supplied from a source material supplying portion 1 is vaporized via coldness releasing process through a first heat exchanger, a second heat exchanger, a third heat exchanger, a vaporizer, and an expander, and the vaporized LNG is passed through the second heat exchanger and a gas-liquid separator to form a gas-liquid mixture to be guided as the source material into the distillation tower; - a branching portion is disposed in a flow passageway for guiding out the gas component from the tower top portion of the distillation tower, one gas component A derived from branching at the branching portion is supplied out via a compressor linked to the expander 41 and a natural gas supplying portion, and the other gas component B derived from branching at the branching portion is guided as a reflux liquid into an upper portion of the distillation tower via the first heat exchanger; - the liquid component guided out from the tower bottom portion of the distillation tower is supplied out as an NGL via the third heat exchanger and a natural gas liquid supplying portion.

Description

Apparatus and method for supplying liquid fuel gas

The present invention relates to an apparatus and a method of supplying a liquid fuel gas using liquefied natural gas (which may be referred to as "LNG" hereinafter) as a source material and using its coldness, and is particularly suitable for supplying methane as a main source. An apparatus and method for a component of a liquid fuel gas for use as a fuel for power generation or the like.

Natural gas (NG) is stored in the form of liquefied natural gas (LNG) for transportation and storage facilities and is mainly used for thermal or municipal gas after it is vaporized. In addition, after the "Yanyan gas revolution", cheap LNG has been available in the LNG spot market, and for this reason, the number of cases using LNG from different countries of origin has increased.

Further, for example, in the case where NG is used as a fuel for power generation, in view of increasing the amount of power generation by increasing the combustion energy, it is preferable when the methane content is 100%. On the other hand, a component having a large carbon number such as ethane (which may hereinafter be referred to as "a component of ethane or the like") is valuable not only as a source material in a chemical plant but also Since the amount of LPG used can be reduced by using the component as a LNG having a higher calorie. In view of such circumstances, it is necessary to provide an energy-efficient method having a component for separating LNG into a methane-rich gas and ethane or the like in an LNG-consuming place (LNG receiving base).

For example, referring to FIG. 10, an apparatus for separating high-pressure natural gas is known. It uses high-pressure natural gas or city gas as a source material in the gas pipeline, and is equipped with a rectification column 110 at a low temperature interval, which stores liquid high-boiling components in the source material gas on the lower side thereof and A methane-rich gas is stored on the upper side thereof; a heat exchanger 102 that cools the source material gas; a reboiler 101 that cools the source material gas that has passed through the heat exchanger 102; and a source material gas expansion device (source material gas expansion valve 103) ) which adiabatically expands the source material gas that has passed through the reboiler 101; a first product gas flow passage M that directs the methane-rich gas present in the upper portion of the rectification column to the outside via the heat exchanger 102 as a a product gas; and a second product gas flow path E that directs the high boiling component present in the lower portion of the rectification column to the outside via the heat exchanger 102 as a second product gas (see, for example, Document 1: JP- A-2013-064077). Here, reference numeral 110a denotes the top of the rectification column 110; reference numeral 110b denotes the bottom of the rectification column 110; and symbol S denotes a source material gas flow path.

However, equipment such as the high pressure natural gas described above may cause various problems such as the following.

(i) In the above separation apparatus, a configuration example is shown in which LNG or the like from a pipe at a normal temperature to about -50 ° C is supplied as a source material and guided to the fine after cooling to about -80 ° C to -120 ° C In the distillation column. The product gas guided from the rectification column is used as cooling for cooling. In this method, the demand (supply amount) of the supplied LNG or its analog or product gas may generally fluctuate due to fluctuations in the demand for thermal power generation or city gas, and the amount of available coldness may also vary. In a conventional apparatus including such a configuration using high-pressure natural gas as a source material, when only the overhead gas or the bottom liquid guided from the rectification column is used, the cooling which can be obtained from the supply in the apparatus cannot be sufficiently ensured. The case of using coldness. The introduction of coldness from the outside in addition to the cumbersome equipment also incurs great energy efficiency losses.

(ii) Since the components of the LNG fluctuate depending on the place of origin, the LNG is usually pressurized and stored in a high pressure tank (for example, about -160 ° C, 8.5 MPa) in a supercooled state. In a conventional apparatus using high-pressure natural gas as a source material, a method of proficient use of its coldness cannot be found, and as in the above separation apparatus, LNG is cooled again by using separation coldness after being processed into a heated state to conform to rectification. The optimum conditions of the column are directed to the rectification column as an adjusted source material. Equipment and methods for the effective use of LNG cooling.

(iii) In addition, in the process of manufacturing the separated methane-rich gas into a compressed gas, it is necessary to add a large amount of energy to pressurize the gas having a normal temperature and a normal pressure, and also to suppress the gas temperature from rising with compression. Coldness. Under the conditions of fluctuations in consumption and supply, there is a big problem in overall energy reduction, efficient use of cold, and overall reduction in energy.

An object of the present invention is to provide an apparatus and method for supplying a liquid fuel gas with high energy efficiency, which effectively utilizes the coldness of LNG and can effectively use the coldness, compression energy and pressure required for preparing a liquid fuel gas. The expansion energy ensures the supply amount of the liquid fuel gas in accordance with fluctuations in the composition or demand amount of the LNG serving as the source material with almost no external energy. Further, another object of the present invention is to provide a highly energy-efficient liquid fuel supply gas and to efficiently take out, for example, methane-rich NG, natural gas liquid (hereinafter referred to as "NGL"), rich by using LNG as a source material. Apparatus and method for various liquid fuel gases of ethane NG and liquefied petroleum gas.

As a result of an eager study repeated to solve the aforementioned problems, the inventors have found that the foregoing objects can be attained by the apparatus and method for supplying a liquid fuel gas shown below, thereby completing the present invention.

The invention is characterized by an apparatus for supplying a liquid fuel gas, wherein the liquefied natural gas is guided as a source material to a distillation column, and then a methane-rich natural gas is prepared from a gas component guided from a top of the column of the distillation column, and is self-distilled The liquid component guided from the bottom of the tower is used to prepare a natural gas liquid, and the apparatus has: - a source material supply flow passage, wherein the supercooled pressurized liquefied natural gas is used as a source material via the source material supply portion, the first heat exchanger, a second heat exchanger, a third heat exchanger, a vaporizer, an expander, a second heat exchanger, and a gas-liquid separator are led to the distillation column; - a natural gas supply flow passage in which a branch of the gas component is produced a gas component A is supplied as natural gas via a compressor and a natural gas supply portion connected to the expander; - a reflux flow passage in which another gas component B produced by branching of the gas component is passed as a reflux liquid via the first heat exchange Directed into the upper part of the distillation column; and - natural gas supply to the flow channel, wherein the liquid component acts as a natural gas via the third heat The converter and the natural gas supply portion are supplied, wherein in the first heat exchanger, the gas component B is condensed by the coldness of the liquefied natural gas supplied from the source material supply portion, thereby preparing the reflux liquid, and the second liquid is prepared. In the heat exchanger, the liquefied natural gas guided from the expander is condensed at a low temperature by the coldness of the liquefied natural gas guided from the first heat exchanger, thereby preparing the source material and kneading in the third heat exchanger. The liquid component guided from the bottom of the tower is cooled by the temperature of the coldness of the liquefied natural gas guided from the second heat exchanger, thereby preparing a natural gas liquid.

The invention is also characterized by a method for supplying a liquid fuel gas, wherein the liquefied natural gas is guided as a source material to a distillation column, and then a methane-rich natural gas is prepared from a gas component guided from a top of the column of the distillation column, and The liquid component guided by the bottom of the distillation tower a natural gas liquid in which all of the supercooled pressurized liquefied natural gas is used as a source material via a source material supply portion, a first heat exchanger, a second heat exchanger, a third heat exchanger, a vaporizer, an expander, and again The two heat exchangers and the gas-liquid separator are guided into the distillation column; (1) guiding the liquefied natural gas supplied from the source material supply portion into the first heat exchanger, and releasing the coldness thereof and the gas component Heat exchange to heat; (2) directing the liquefied natural gas guided from the first heat exchanger to the second heat exchanger, and releasing the coldness through the heat of the liquefied natural gas guided from the self-expander Exchanging to heat; (3) directing the liquefied natural gas guided from the second heat exchanger to the third heat exchanger, and heating by releasing the coldness thereof by heat exchange with the liquid component; (4) The liquefied natural gas guided from the third heat exchanger is guided to the vaporizer and vaporized by heating; (5) the liquefied natural gas guided from the vaporizer is guided into the expander, and is adiabatic expansion Pressure and temperature reduction; (6) self-expander The extracted liquefied natural gas is again guided into the second heat exchanger and condensed by a temperature decrease by heat exchange in the step (2); (7) the condensate guided from the second heat exchanger The liquefied natural gas is led to the gas-liquid separator for gas-liquid separation; (8) the gas separated in the gas-liquid separator is guided as a source material to the upper portion of the middle column of the distillation column, and in the gas-liquid separator The separated liquid is guided as a source material to the lower portion of the intermediate column of the distillation column; - a gas component A produced by the branching of the gas component is connected to the compressor connected to the expander Adiabatic compression is carried out, and the natural gas is supplied as heated and pressurized; - another gas component B produced by branching of the gas component is condensed by a temperature decrease by the coldness of the liquefied natural gas in the step (1) And returning as a reflux liquid to the upper portion of the distillation column; and - the liquid component is lowered by the coldness of the liquefied natural gas in the step (3), and is supplied as a natural gas liquid.

A configuration such as that described above makes it possible to provide an apparatus and method for supplying a liquid fuel gas with high efficiency, which effectively uses the coldness of LNG, and can effectively use the coldness required in preparing a liquid fuel gas, The compression energy and the expansion energy ensure the supply amount of the liquid fuel gas according to fluctuations in the composition or demand amount of the LNG serving as the source material with almost no external energy.

Specifically, the coldness of the LNG can be released by sequentially discharging the entire amount of the cold state of the pressurized LNG in the supercooled state through the first to third heat exchangers, and in the preparation of the reflux liquid, and in the gas-liquid mixed state after the adiabatic expansion. The source material and NGL are used in coldness for complete use.

In addition, by using the coldness of the LNG in its release process for temperature reduction and condensation of the LNG itself after vaporization, it is formed in the LNG flow to form a countercurrent flow during the preparation of the source material introduced into the distillation column. And the intersection of the coldness is received, so that the coldness of the LNG can be further effectively used.

The invention also features an apparatus for supplying a liquid fuel gas as described above, further comprising: - a fourth heat exchanger and a fifth heat exchanger, which are provided in a third heat exchanger in the source material supply flow passage Downstream a second distillation flow channel, wherein a part or the whole amount of the liquid component guided from the bottom of the column is led to the second distillation column; - a second natural gas supply flow channel, wherein the second distillation column is a gas component C produced by branching the second gas component guided from the top of the two towers is supplied as a second natural gas through the second compressor, the second vaporizer and the second natural gas supply portion; - a second reflux flow channel, Wherein another gas component D produced by branching of the second gas component guided from the top of the second column of the second distillation column is guided as a second reflux liquid to the second distillation column via the fourth heat exchanger And a liquid petroleum gas supply flow passage, wherein the second liquid component guided from the bottom of the second tower of the second distillation column is supplied as liquefied petroleum gas through the fifth heat exchanger and the liquefied petroleum gas supply portion Wherein the helium gas component D is condensed in the fourth heat exchanger by the coldness of the liquefied natural gas guided from the third heat exchanger to prepare a second reflux liquid, and the crucible is guided from the bottom of the second tower Second liquid Component temperatures reduce the degree of supercooling by a guide from the fourth heat exchanger LNG occurs in the fifth heat exchanger, thereby producing liquefied natural gas.

The invention also features a method of supplying a liquid fuel gas as described above, wherein - a portion or all of the liquid component directed from the bottom of the column is directed to the second distillation column; - from the second Preparing an ethane-rich second natural gas by using a second gas component guided from a top of the second column of the distillation column; - preparing liquefied petroleum gas from a second liquid component directed from the bottom of the second column of the second distillation column; instead of step (4), (4a) will be from the third after passing steps (1) to (3) The liquefied natural gas guided by the heat exchanger is further guided into the fourth heat exchanger and heated by releasing its coldness by heat exchange with the second gas component; (4b) from the fourth heat exchanger The guided liquefied natural gas is guided into the fifth heat exchanger and heated by releasing its coldness by heat exchange with the second liquid component; (4c) being guided from the fifth heat exchanger The liquefied natural gas is introduced into the vaporizer and vaporized by heating; thereafter, the resultant is guided as a source material to the distillation column after passing through steps (5) to (8); - is produced by branching of the second gas component a gas component C is adiabatically compressed by a second compressor and supplied as a heated and pressurized second natural gas; - another gas component D produced by branching of the second gas component is passed through the steps The coldness of the liquefied natural gas in (4a) is lowered to condense, and is returned as the second reflux liquid to the first In the upper portion of the distillation column; and - the second liquid component as a liquefied petroleum gas by the step of cooling the liquefied natural gas (4b) is supplied to reduce the temperature occurs.

A configuration such as that described above makes it possible to provide a highly energy-efficient liquid fuel gas supply and to efficiently extract methane-enriched NG and NGL and various liquid fuel gases such as ethane-rich NG and liquefied petroleum gas by using LNG as a source material. Equipment and methods. specific In other words, by arranging two tandem distillation columns with respect to the LNG serving as the source material, each liquid fuel gas can be supplied separately in any amount, and the liquid fuel gas obtained by blending the gases at an arbitrary ratio is obtained. It can also be supplied according to the instructions.

Further, the pressurized LNG in the supercooled state still has an effective cold after releasing a predetermined amount of coldness via the first to third heat exchangers. By using this residual coldness in the preparation of the ethane-rich gas, propane and the like via the fourth heat exchanger and the fifth heat exchanger, the present invention makes it possible to efficiently prepare various liquids with little external energy required. Fuel gas, such as LPG.

The present invention is also characterized by the apparatus for supplying a liquid fuel gas described above, wherein the entire amount of the liquefied natural gas supplied from the source material supply portion is processed into a normal temperature pressurized state via the first to third heat exchangers and the vaporizer, Thereafter, temperature reduction and pressure reduction are caused by adiabatic expansion by the expander, further low-temperature condensation is conducted by being redirected to the second heat exchanger, and separation is carried out by guiding to the gas-liquid separator, followed by The gas separated in the gas-liquid separator is guided as a source material to the upper portion of the intermediate column of the distillation column, and the liquid separated in the gas-liquid separator is guided as a source material to the lower portion of the intermediate column of the distillation column.

The apparatus for supplying liquid fuel gas described above can achieve effective use of cold (not used in the past) to impart and receive thermal energy, since the entire amount of LNG cooling, especially the supercooled pressurized LNG, can be used. . During this process, the supplied LNG is in a high pressure state, and the LNG serving as a source material in the distillation column is preferably set to have a pressure to reach an optimum distillation condition.

The present invention accomplishes this function by vaporizing the entire amount of supplied LNG to release its coldness and thereafter adiabatically expanding and cooling the coldness to prepare the material. This makes it possible to ensure optimum temperature and pressure conditions in the distillation column, even in the supply, composition and temperature of LNG. Or when the pressure fluctuates, and it is possible to greatly reduce the energy loss accompanying the cold transmission.

The invention is also characterized by the apparatus for supplying a liquid fuel gas as described above, wherein the expander is composed of a plurality of expansion turbines arranged in series; the liquefied natural gas guided from the carburetor is branched into each expansion turbine. One or more expansion turbines are connected to the same number of compressors; other expansion turbines are connected to the same number of generators; and gas component A is directed into the compressor.

In the apparatus for supplying liquid fuel gas, in addition to the supply amount, composition or delivery temperature and pressure fluctuation of LNG, the methane-rich natural gas produced (which may be referred to as "NG" hereinafter) or natural gas liquid (which may be hereinafter The supply amount or supply temperature and pressure called "NGL" may fluctuate. Further, in order to improve the total energy efficiency in the apparatus for supplying the liquid fuel gas, it is preferable to secure electric energy as a driving power source in the apparatus.

The present invention makes it possible to ensure optimum conditions according to the above fluctuations by using an expander having a plurality of expansion turbines and adjusting the operation amount of each turbine and a compressor connected thereto, and it is also possible to The operation ensures the amount of power generation by connecting a portion of the generator to the expansion turbine.

The present invention is also characterized by the above-described apparatus for supplying a liquid fuel gas, which further has a flow passage connected between the source material supply portion and the upper portion of the distillation column so as to be supplied from the source material supply portion when the apparatus is activated A portion of the liquefied natural gas is introduced as a source material through the upper portion of the distillation column into the distillation column.

When the distillation column is started, it takes a predetermined period of time until an optimum gas-liquid equilibrium is formed in the interior of the column. In particular, part of the reflux is one of the rate limiting conditions for the formation of a stable gas-liquid equilibrium. The present invention allows the introduction of low temperature LNG as a source material by introduction through the upper portion of the distillation column. It is supplemented to form such a reflux liquid, so that a stable gas-liquid equilibrium can be quickly formed.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a basic configuration example of an apparatus for supplying a liquid fuel gas according to the present invention; Fig. 2 is a verification result as exemplified in a basic configuration example of an apparatus for supplying a liquid fuel gas according to the present invention; A schematic diagram illustrating a second exemplary structure of an apparatus for supplying a liquefied gas according to the present invention; and FIG. 4 is a verification result as exemplified in the second exemplary structure of the apparatus for supplying a liquefied gas according to the present invention; A schematic view of a third exemplary structure of an apparatus for supplying a liquefied gas according to the present invention; and FIG. 6 is a schematic view showing a fourth exemplary structure of an apparatus for producing a liquefied gas according to the present invention; and FIG. 7 is a manufacturing apparatus according to the present invention. The verification result exemplified in the fourth exemplary structure of the apparatus for liquefying gas; FIG. 8 is a schematic view showing a fifth exemplary structure of the apparatus for producing a liquefied gas according to the present invention; and FIG. 9 is a liquefaction as in the manufacture according to the present invention. The verification results exemplified in the fifth exemplary structure of the gas apparatus; and FIG. 10 is a diagram illustrating the separation of high pressure natural gas according to the prior art. Prepared schematic.

In the apparatus for supplying a liquid fuel gas according to the present invention (hereinafter referred to as "the apparatus of the present invention"), liquefied natural gas (LNG) is introduced as a source material into a distillation column, and then guided from the top of the column from the distillation column. The gas component produces methane-rich natural gas (NG), and natural gas liquid (NGL) is prepared from the liquid component guided from the bottom of the distillation column. The apparatus includes a source material supply flow channel, wherein the supercooled pressurized LNG is used as a source material via the source material supply portion, the first heat exchanger, the second heat exchanger, the third heat exchanger, the vaporizer, the expander, and again The second heat exchanger and the gas-liquid separator are led to the distillation column; the natural gas is supplied to the flow channel, wherein a gas component A produced by the branching of the gas component acts as a NG via the compressor and the natural gas supply portion connected to the expander Supplying; a reflux flow channel, wherein another gas component B produced by branching of the gas component is introduced as a reflux liquid through the first heat exchanger to the upper portion of the distillation column; and the natural gas liquid is supplied to the flow channel, wherein the liquid group The fraction is supplied as NGL via the third heat exchanger and the natural gas supply portion.

The gas component B is condensed in the first heat exchanger by the coldness of the LNG supplied from the source material supply portion, thereby preparing a reflux liquid. The LNG guided from the expander is subjected to low-temperature condensation in the second heat exchanger by the coldness of the LNG guided from the first heat exchanger, thereby preparing the source material. The liquid component guided from the bottom of the column is subjected to a temperature decrease in the third heat exchanger by the coldness of the LNG guided from the second heat exchanger, thereby preparing NGL. Hereinafter, specific examples of the invention will be described with reference to the accompanying drawings.

Here, in the specific example of the present invention, conditions such as temperature, pressure, and flow rate of the respective portions may be appropriately changed depending on other conditions such as the kind of the gas and the flow rate.

A basic configuration example of the apparatus of the present invention will be exemplified in Fig. 1 (first configuration example) An overview. In the apparatus of the present invention, pressurized LNG in a supercooled state is introduced as a source material into the distillation column 10; methane-rich NG is prepared from a gas component (top gas) guided from the top portion 11 of the column; The liquid component (bottom liquid at the bottom of the column) guided by the bottom portion 12 is used to prepare NGL. Here, the LNG supplied from the source material supply portion 1 is vaporized via the first heat exchanger 21, the second heat exchanger 22, the third heat exchanger 23, the vaporizer 30, and the expander 41 via the cold release process, and the vaporization The LNG passes through the second heat exchanger 22 and the gas-liquid separator 50 to form a gas-liquid mixture, which is guided as a source material to the distillation column 10. In view of the passage of the LNG, the intersection of the LNG and itself is formed, and the returned LNG is given and received coldness in a countercurrent manner at the intersection. At the intersection, the cooling of the LNG during the release is used to lower the temperature and the LNG itself condenses after vaporization. In other words, in the LNG stream in the process of preparing the source material introduced into the distillation column, not only the coldness of the LNG is released but also received, that is, a part of the released coldness is received, so that the coldness can be further more effectively used.

Specifically, a source material supply flow channel is provided, wherein the supercooled pressurized LNG is used as a source material via the source material supply portion 1, the first heat exchanger 21, the second heat exchanger 22, the third heat exchanger 23, The vaporizer 30, the expander 41, the second heat exchanger 22, and the gas-liquid separator 50 are guided to the distillation column 10. The low-temperature high-pressure LNG (for example, about -150 ° C, about 6 MPa) is supplied from the source material supply portion 1 in a liquid form, and is vaporized by the vaporizer 30 after sequentially releasing the coldness via the first to third heat exchangers 21 to 23.

The maximum coldness of LNG can be used. The vaporized LNG is adiabatically expanded by the expander 41, a temperature drop occurs and a pressure is also reduced to a predetermined pressure (e.g., about 2.3 MPa) as the source material to form a gaseous low temperature and low pressure LNG.

The gaseous LNG is again further subjected to temperature reduction by the second heat exchanger 22 to a predetermined temperature which is optimal as the source material. The predetermined temperature at this time means that the LNG having the predetermined composition is Condensation at the optimum pressure forms the temperature at which the gas and liquid coexist. For example, in the case of LNG having the composition exemplified in Table 1 below, about -80 ° C at about 2.3 MPa is suitable. The condensed LNG is separated into a gas and a liquid by the gas-liquid separator 50, and is guided to the distillation column 10.

At this time, it is preferable that the gas separated by being guided into the gas-liquid separator 50 is guided as a source material to the upper portion (the upper portion of the intermediate tower) of the intermediate column portion 13 of the distillation column 10, and guided by The liquid separated into the gas-liquid separator 50 is guided as a source material to the lower portion (the lower portion of the intermediate column) of the intermediate column portion 13 of the distillation column 10. The gas-liquid separator 50 can function as a preset distillation column by guiding the cryogenic liquid LNG together with a reflux liquid described later into the lower portion of the intermediate column and guiding the low-temperature gaseous LNG into the upper portion of the intermediate column. Thereby, the efficiency of separating into a methane component and components other than methane can be further improved.

In this case, it is preferable that the entire amount of the LNG supplied from the source material supply portion 1 is processed into the normal temperature pressurized state via the first to third heat exchangers 21 to 23 and the vaporizer 30, and thereafter passed through the expander 41. The adiabatic expansion occurs with a decrease in temperature and a decrease in pressure, which is further guided to the second heat exchanger 22 for further low-temperature condensation, and is guided to the gas-liquid separator 50 for separation, and then guided to the gas-liquid The gas separated in the separator 50 is guided as a source material to the upper portion (the upper portion of the intermediate column) of the intermediate column portion 13 of the distillation column 10, and the liquid separated by being guided into the gas-liquid separator 50 as a source The material is guided to the lower portion of the intermediate tower portion 13 of the distillation column 10 (the lower portion of the intermediate column).

Even when the supply amount, composition, temperature or pressure of the LNG fluctuates, the optimum temperature and pressure conditions in the distillation column 10 can be ensured, and the energy loss accompanying the coldness transmission can be greatly reduced. However, when the amount of cold supplied exceeds an amount sufficient to produce the desired NG and NGL, the coldness can be withdrawn in the middle of the source material supply flow path for other purposes.

This applies, for example, to the case where LNG containing a large amount of methane is supplied; the amount of coldness of available LNG is large; a large amount of NG can be prepared from the distillation column 10; and NGL can be prepared with a smaller amount of coldness.

In the apparatus of the present invention, the branch portion is disposed in the flow passage for guiding the gas component (top gas) from the column top 11 of the distillation column 10. The apparatus of the present invention is equipped with a natural gas supply flow passage in a branch portion, wherein the gas component A produced by the branch at the branch portion is made methane-rich NG via the compressor 42 connected to the expander 41 and is supplied via the natural gas supply portion 2 Supply. The gas at the top of the column is methane-rich NG having a low temperature and a low pressure (for example, about -100 ° C and about 2.3 MPa), and therefore it is necessary to carry out a treatment of temperature rise and pressure rise so as to have a predetermined temperature and pressure (for example, about - The product NG at 30 ° C and about 6 MPa) was taken out.

In the apparatus of the present invention, the desired product NG can be supplied by adiabatic compression of a gas component A produced by branching by a compressor 42 for preparing a source material connected to the expander 41 without introducing additional energy. Out.

However, when the gas at the top of the column is directed at a low temperature and low pressure state equal to the product NG, the gas at the top of the column is supplied directly from the top of the column 11 without such treatment.

In addition, compressor 42 means a configuration that includes not only a single unit configuration, but also a configuration in which a plurality of compressors are arranged in series (in the case of, for example, a larger compression ratio) or a plurality of compressors in parallel configuration (such as independent of expansion). When the compressor 41 performs the compression ratio adjustment).

The apparatus of the present invention is equipped with a reflux flow passage in the other branch portion, in which the gas component B produced by the branch at the branch portion is introduced as reflux into the upper portion 14 of the distillation column via the first heat exchanger 21. The branch gas component B is introduced into the first heat exchanger 21 by ensuring sufficient heat of condensation and cooling energy to be thermally exchanged with the LNG having the greatest amount of coldness In other words, it is effectively condensed, and thereafter used as a reflux liquid sent to the distillation column 10, thereby achieving effective use of LNG coldness and also performing a buffering function to ensure that the supply amount of the product gas prepared from the gas component A occurs. The stable performance of the distillation column 10 when fluctuating.

Specifically, for example, when the amount of the product NG is decreased, the distillation column 10 can reduce the supply flow rate of the gas component A (for example, about 500,000 to the point where the flow rate guided by the gas at the top of the column is not fluctuated. 400,000 kg/h) and increase the flow rate of the gas component B (for example, about 500,000 to 600,000 kg/h) to operate.

By increasing the reflux liquid in a state in which the distillation efficiency of the distillation column 10 is maintained, the NG production can be lowered, and an increase in the production of NGL can be obtained. Conversely, when the amount of product NG is increased, the NG yield can be increased, and the NGL yield can be lowered by lowering the flow rate of the gas component B and lowering the amount of the reflux liquid.

The apparatus of the present invention is equipped with a natural gas liquid supply flow passage in which a liquid component (bottom liquid) guided from the bottom portion 12 of the distillation column 10 is made into NGL via the third heat exchanger 23 and supplied through the natural gas liquid supply portion 3. Out. The bottom liquid of the column is an NGL having a normal temperature and a low pressure (for example, about 25 ° C and about 2.3 MPa), so that a temperature reduction process (and, as the case may be, a further pressure reduction process) must be performed so as to have a predetermined temperature and pressure (for example, The product NGL was taken out at about -10 ° C and about 2.3 MPa).

In the apparatus of the present invention, the desired product NGL can be supplied by effective heat reduction of the liquid at the bottom of the column by heat exchange with LNG having a coldness without introducing additional energy.

Here, when the amount of LNG serving as a source material of a component having 3 or more carbon numbers (such as propane) is large, the liquid at the bottom of the column can be actually made without lowering the temperature. The product NGL is supplied. Furthermore, in the apparatus of the invention (although not illustrated in the drawings), on the one hand the liquid at the bottom of the column can be branched to feed the product NGL, and on the other hand the liquid at the bottom of the column can be heated via a reboiler (not illustrated) It is guided to the lower portion 15 of the distillation column to obtain a high distillation function.

As described above, in the apparatus of the present invention, the LNG supplied from the source material supply portion 1 sequentially releases a part of the coldness in the first heat exchanger 21 to condense the gas at the top of the column (gas component B) to prepare a reflux liquid, Further releasing a portion of the coldness in the second heat exchanger 22 to cause the LNG guided from the expander 41 to be condensed at a low temperature to prepare a source material, and releasing a residual amount of coldness in the third heat exchanger 23 to make the tower The bottom liquid is subjected to a temperature decrease to prepare NGL. The LNG supplied from the source material supply portion 1 means, for example, pressurized LNG in a supercooled state that has been stored in a high pressure tank. By fully using this coldness, an energy-efficient apparatus for supplying liquid fuel gas can be constructed.

The LNG supplied in the apparatus of the present invention has, for example, the composition exemplified in Table 1 below, wherein the components are fluctuated according to the origin and the LNG is stored in the high pressure tank under different temperature and pressure conditions. Specifically, the LNG is stored under a temperature condition of about -120 ° C to -160 ° C and a pressure of about 5 MPa to 10 MPa.

Here, the LNG according to the present invention means to include a zeolitic gas such as that described in addition to the conventionally mentioned LNG, or to mean not only refined LNG but also non-refined LNG.

The first to third heat exchangers 21 to 23 are not particularly limited; however, for example, a plate fin type heat exchanger, a shell and tube type heat exchanger or the like can be used. Specifically, in the first heat exchanger 21 that performs heat exchange between the low temperature liquid LNG and the low temperature gaseous NG, and in the second heat exchanger 22 that performs heat exchange between the low temperature liquid LNG and the low temperature gaseous LNG, the coldness It can be more efficiently given and received by using a plate-fin heat exchanger having a larger heat transfer area. Further, in the third heat exchanger 23 which performs heat exchange between the low temperature liquid LNG and the normal temperature liquid NGL, the coldness can be achieved by using a shell and tube type heat exchanger having a small passage resistance and a large heat transfer area. Give and receive more effectively.

In the case of using the apparatus of the present invention, the LNG having the composition exemplified in Table 1 above is supplied as a source material in order to verify the temperature (°C), pressure (MPa), flow rate (kg/h) in each part, and Composition (G/L: gas/liquid).

(i) verification results

When LNG (-150 ° C, 6.00 MPa) was supplied at 427,000 kg/h, the results of temperature, pressure, flow rate, and composition in each of parts a to r in Fig. 2 are as exemplified in Table 2 below.

(ii) Subsequently, the input and output of energy in the apparatus of the present invention are compared with a conventional "separation device" for verification. In the conventional "separation apparatus" in which the pressure of the source material LNG is lowered to a predetermined pressure using a separation expander and the separated NG is separately pressurized using a compressor to prepare a reflux liquid using external cooling, under the same conditions as the apparatus of the present invention The amount of external energy required in the conventional "separation device" is estimated by supplying LNG to the distillation column and supplying NG and NGL under the same conditions, and the result is the external energy required in the apparatus of the present invention. The supply is compared. As will be understood from Table 3 below, the following results have been obtained: when compared with the conventional "separation device", the supply of external energy in the apparatus of the present invention is smaller, and the total amount is 9,393 kW (as in terms of power conversion). .

An overview of a second configuration example of the apparatus of the present invention will be shown in FIG. In the following, the common constituent elements of the basic construction will be denoted by common reference numerals and reference symbols, and the description thereof may be omitted.

The apparatus of the present invention has a configuration in which, in the source material supply flow path of the basic configuration example, the expander 41 is composed of expansion turbines 41a, 41b arranged in parallel; the LPG guided from the vaporizer 30 is branched to be guided to the expansion turbine In each of 41a, 41b; expansion turbine 41a is coupled to compressor 42; and expansion turbine 41b is coupled to generator 60. The function under the optimum conditions of the apparatus of the present invention including the distillation column 10 can be supplied by the fluctuation of the supply amount, composition, supply temperature, pressure, and the like of the LNG or the supply amount of the NG and NGL supplied thereto, and the supply temperature. The fluctuation of the pressure and the like is adjusted to adjust the operation amount of the expansion turbines 41a, 41b and the operation amount of the compressor 42.

Further, by connecting the generator 60 and the expansion turbine 41b, the amount of power generation corresponding to the operation amount of the expansion turbine 41b can be secured. Here, a configuration example is shown in which the expander 41 is composed of two expansion turbines 41a, 41b arranged in parallel; however, the number of expansion turbines This is not limited to this.

The apparatus of the present invention is meant to include a configuration in which the expander is comprised of two or more expansion turbines 41a, 41b...41n (not illustrated in the drawings). By connecting one or more expansion turbines with the same number of compressors, the operation amount of the expander (the amount of adiabatic expansion of LNG, temperature and pressure) can be adjusted, and the supply amount of NG supplied, the supply temperature, The fluctuation of the pressure and the like to adjust the operating amount (compression ratio) of the compressor.

For example, the compression ratio of the compressor can be changed by connecting two expansion turbines having different expansion functions with two compressors having different compression ratios and by changing the operation ratio of the compressor while maintaining a constant total expansion function. The amount of operation of the compressor varies.

At this time, a high compression ratio can be obtained when the gas component A branches and is guided into each of the series compressors, and high adjustment accuracy can be obtained when the gas component A branches and is guided to each of the parallel compressors. The compression ratio. Furthermore, by connecting one or more expansion turbines with the same number of generators, the amount of operation of the expander can be adjusted, and the amount of operation of the generator can be adjusted according to the amount of power generation required.

For example, the amount of power generation can be changed by connecting two expansion turbines having different expansion functions with two generators having different power generation capabilities and by changing the operation ratio of the generator while maintaining a constant total expansion function. The amount of operation changes.

In the case of using the second configuration example of the apparatus of the present invention, the LNG having the composition exemplified in Table 1 above is supplied as a source material in order to verify the temperature (°C), pressure (MPa), and flow rate in each part ( Kg/h) and composition (G/L: gas/liquid). When LNG (-150 ° C, 6.00 MPa) was supplied at 427,000 kg/h, the temperature in each of the portions s to v in Fig. 4 was obtained except for each of the portions a to r in Fig. 2 Pressure, flow rate and Composition, as exemplified in Table 4 below. Further, a power generation amount of about 500 kW/h can be obtained from the generator 60 connected to the expansion turbine 42.

An overview of a third configuration example of the apparatus of the present invention will be shown in FIG. The apparatus of the present invention according to the third configuration example has a configuration in which a flow passage Ld connected between the source material supply portion 1 and the upper portion 14 of the distillation column is provided, so that the LNG supplied from the source material supply portion 1 when the apparatus is activated is started A part of it is guided as a source material to the distillation column 10 via the upper portion 14 of the distillation column 10. By introducing the supercooled LNG into the column when the distillation column 10 is started, the formation of reflux in the column can be supplemented, and the reflux is formed to form one of the rate limiting conditions for stabilizing the gas-liquid equilibrium, so that the distillation can be started quickly. Tower 10.

Specifically, in the column, by providing a valve Lv in the flow channel Ld and introducing via the upper portion 14 of the distillation column 10, for example, having a low temperature and a high pressure (for example, about -150 ° C and about 6 MPa) and having the above Table 1 The LNG of the exemplified composition is simultaneously restricted to a rapid formation of a gas-liquid equilibrium under low temperature and low pressure conditions (for example, about -150 ° C and about 2.3 MPa) in the same manner as in the basic configuration example.

The method of supplying a liquid fuel gas according to the present invention allows LNG to be introduced as a source material into a distillation column by using the apparatus of the invention as described above, followed by preparation of a gas component guided from the top of the column of the distillation column Methane-rich NG, and NGL is prepared from the liquid component guided from the bottom of the column of the distillation column.

Here, the entire amount of supercooled pressurized LNG is used as a source material via the source material supply portion, the first heat exchanger, the second heat exchanger, the third heat exchanger, the vaporizer, the expander, and the second heat exchange again. The gas and liquid separators are led to the distillation column. The coldness of the LNG can be maximally used by sequentially releasing the coldness of the entire amount of the supercooled pressurized LNG through the first to third heat exchangers to vaporize the entire amount of LNG.

The vaporized LNG is adiabatically expanded and further reduced in temperature and condensed by the coldness of the LNG in the second heat exchanger, so that the LNG can be adjusted to become the optimum source material for the distillation treatment, and in addition, the LNG can be effectively used. The coldness. Specifically, a configuration example including the following steps can be proposed as an example.

Herein, in the following description, each part of the apparatus of the present invention is indicated by the reference symbols illustrated in FIG. 1, and the conditions exemplified in Table 2 above can be applied as conditions for each gas or liquid; however, It is to be understood that the invention is not limited thereto.

The pressurized LNG stored in the supercooled state was prepared into gaseous LNG by the following procedure.

(1) The LNG supplied from the source material supply portion 1 is guided into the first heat exchanger 21, and is heated by releasing its coldness by heat exchange with the gas component B guided from the tower top portion 11. For example, LNG having a temperature of about -150 ° C and a pressure of about 6 MPa is heated to about -124 ° C by releasing its coldness in the first heat exchanger 21 . At the same time, gas component B having a temperature of about -104 ° C and a pressure of about 2.3 MPa was cooled to prepare a condensate of about -104 ° C. The prepared condensate is introduced as a reflux to the upper portion 14 of the distillation column.

(2) The LNG guided from the first heat exchanger 21 is guided into the second heat exchanger 22, and is heated by releasing its coldness via heat exchange with the LNG guided from the expander 41. For example That is, LNG having a temperature of about -124 ° C and a pressure of about 6 MPa is heated to about -65 ° C by releasing its coldness in the second heat exchanger 22 . At the same time, LNG having a temperature of about -36 ° C and a pressure of about 2.3 MPa was cooled to prepare a condensate (gas-liquid mixture) of about -94 ° C. The prepared condensate is introduced as a reflux to the upper portion 14 of the distillation column.

(3) Leading the LNG guided from the second heat exchanger 22 into the third heat exchanger 23, and by exchanging its coldness via heat exchange with the liquid component guided from the bottom portion 12 of the tower. heating. For example, LNG having a temperature of about -65 ° C and a pressure of about 6 MPa is heated to about -64 ° C by releasing its coldness in the third heat exchanger 23 . At the same time, the bottom liquid of the column having a temperature of about 21 ° C and a pressure of about 2.3 MPa was cooled to prepare NGL of about 10 ° C.

(4) The LNG guided from the third heat exchanger 23 is guided into the vaporizer 30 and vaporized by heating. For example, LNG having a temperature of about -64 ° C and a pressure of about 6 MPa is vaporized by releasing its coldness in the vaporizer 30 and heated to about 15 ° C.

(5) The gaseous LNG guided from the vaporizer is guided as a source material to the distillation column by the following steps.

(6) The LNG guided from the vaporizer 30 is guided to the expander 41, and the pressure is lowered and the temperature is lowered by the adiabatic expansion. For example, gaseous LNG having a temperature of about 15 ° C and a pressure of about 6 MPa is adiabatically expanded by expander 41, and the temperature is lowered to about -36 ° C and the pressure is reduced to about 2.3 MPa. A portion of the gaseous LNG can be liquefied (gas-liquid mixture state). The reduced pressure is based on the composition of the LNG and the characteristics of the distillation column 10 are set to be under optimal distillation conditions.

(7) The LNG guided from the expander 41 is again guided into the second heat exchanger 22, and condensed by a temperature decrease by heat exchange in the step (2). For example, LNG cooled to about -36 ° C in the second heat exchanger 22 by receiving temperature of about -124 ° C and a pressure of about 6 MPa and the cooling of the LNG whose temperature is lowered to about -94 ° C to liquefy (gas-liquid mixture state). The cooling temperature is set based on the composition of the LNG and the characteristics of the distillation column 10 to be under optimum distillation conditions. At the same time, the LNG which has released the cooling is heated to about -65 °C.

(8) The LNG containing the condensate guided from the second heat exchanger 22 is guided to the gas-liquid separator 50 to perform gas-liquid separation. For example, LNG cooled to about -94 ° C is separated into a gas having a volume ratio of about 3/5 and a liquid having a volume ratio of about 2/5 in the gas-liquid separator 50.

(9) The gas separated in the gas-liquid separator 50 is guided as a source material to the upper portion of the intermediate column of the distillation column 10, and the liquid separated in the gas-liquid separator 50 is guided as a source material to the distillation column 10. In the lower part of the middle tower. At this time, the separated gas has a higher methane concentration than the LNG of the source material, and the concentration of the separated liquid component (such as ethane) is higher than the LNG of the source material (which may be referred to as distillation pretreatment).

The LNG self-guided to the distillation column 10 is supplied with methane-rich NG from the gas at the top of the column 11 from the column top of the distillation column 10, and is supplied from the bottom of the column from the bottom 12 of the column 10 of the distillation column 10. NGL.

(8a) The LNG guided to the distillation column is separated into a gas at the top of the methane-rich column and a bottom liquid containing a component such as ethane as a main component.

Specifically, for example, in the distillation column 10 having a pressure of about 2.3 MPa, a temperature at the top of the column of about -104 ° C, and a temperature at the bottom of the column of about 21 ° C, the gaseous LNG guided into the upper portion of the intermediate column forms an upward flow and causes It is in contact with the descending gas liquid, which is mainly composed of a methane-rich reflux liquid, which improves the purity of methane (top gas). On the other hand, the liquid LNG guided to the lower portion of the intermediate column forms a descending flow and is brought into contact with the rising gas liquid, and the upward flow contains a component such as ethane and is heated at the bottom of the column to raise a component such as ethane ( The purity of the liquid at the bottom of the column.

(8b) The methane-rich NG system is prepared from the gas at the top of the column guided from the top of the column of the distillation column.

From the top of the column 11, a gas at a temperature of about -104 ° C and a pressure of about 2.3 MPa and containing 99.9% or more of methane is introduced, and about 90% of it is adiabatically compressed by the compressor 42 to, for example, about - As gas component A at 43 ° C and about 6 MPa, methane-rich NG is produced, which is supplied through the natural gas supply portion 2.

By using the compressor 42 connected to the expander 41, the desired product NG can be supplied without introducing additional energy. In the process, about 20% of the overhead gas of the column is introduced as a gas component B into the first heat exchanger 21, in which a condensate of about -104 ° C is prepared, and the prepared condensate is used as a reflux liquid. To the upper portion 14 of the distillation column.

(8c) The NGL system is prepared from a liquid at the bottom of the column which is guided from the bottom of the column of the distillation column.

From the bottom 12 of the column, a bottom liquid having a temperature of about 21 ° C and a pressure of about 2.3 MPa and containing 99.9% or more of components such as ethane is introduced and cooled to about 10 ° C via the third heat exchanger 23 NGL is produced and supplied through the natural gas liquid supply portion 3. The desired product NGL can be supplied by the effective use of LNG.

Furthermore, in the apparatus of the invention (although not illustrated in the drawings), on the one hand the liquid at the bottom of the column can be branched to feed the product NGL, and on the other hand the liquid at the bottom of the column can be heated via a reboiler (not illustrated) It is guided to the lower portion 15 of the distillation column to obtain a high distillation function.

As shown in Table 1 above, the LNG serving as the source material contains not only methane constituting the main component but also substances having different boiling points such as ethane, propane and butane. These materials are used not only as fuels but also as extremely useful chemical materials, making the demand for each of them high.

In the apparatus of the present invention, not only NG and NGL but also ethane-rich natural gas (sNG) And a liquid fuel gas (LPG) having 3 or more carbon numbers can be obtained by arranging a plurality of series distillation columns instead of a single distillation column as in the above configuration example and sequentially taking out a substance containing a low boiling point substance as a main component. Any amount is supplied separately.

In the following, a description will be given regarding a fourth configuration example in which two distillation columns are placed on the substrate of the first configuration example described above, and in the fifth configuration example, in the fourth configuration example, Two distillation columns were placed on the substrate of the second configuration example described above.

Here, a description will be omitted of a configuration example corresponding to the third configuration example described above and a configuration example in which three or more distillation columns are disposed; however, it may be added to the fourth configuration example by adding equivalents And the configurations of the configurations of the fifth configuration example are applied.

An overview of a fourth configuration example of the apparatus of the present invention will be shown in FIG. In the following, the common constituent elements of the basic construction will be denoted by common reference numerals and reference symbols, and the description thereof may be omitted. The fourth configuration example has a configuration further including a fourth heat exchanger 24 and a fifth heat exchanger 25 which are provided in the source material supply flow passage in the basic configuration example (first configuration example) for the third heat exchange Downstream of the device 23; a second distillation flow channel in which at least a portion of the liquid component guided from the bottom 12 of the column of the distillation column (hereinafter referred to as "first distillation column") 10 is led to the second distillation column a second natural gas supply flow passage, wherein a gas component C produced by a branch of the second gas component guided from the second column top 71 of the second distillation column 70 is used as the second natural gas via the second compression The machine 43, the second vaporizer 31 and the second natural gas supply portion 4 are supplied; the second reflux flow passage is produced by a branch of the second gas component guided from the second tower top 71 of the second distillation column 70. Another gas component D is introduced as a second reflux liquid through the fourth heat exchanger 24 to the upper portion 74 of the second distillation column 70; and the liquid fossil The oil and gas supply flow path, in which the second liquid component guided from the second column bottom 72 of the second distillation column 70 is supplied as liquefied petroleum gas through the fifth heat exchanger 25 and the liquefied petroleum gas supply portion 5.

In addition to the functions of the basic configuration example, not only NG and NGL but also sNG and LPG can be supplied separately in any amount by arranging two tandem distillation columns 10, 70 with respect to LNG serving as a source material. Further, LNG having residual effective cooling after releasing a predetermined amount of coldness via the first heat exchanger 21 to the third heat exchanger 23 may be guided to the fourth heat exchanger 24 and the fifth heat exchanger 25 In order to exchange heat with the gas at the top of the tower or the liquid at the bottom of the second distillation column 70 via these heat exchangers, sNG and LPG can be efficiently produced with little external energy.

Specifically, a part or the whole amount of the liquid component having the normal temperature and the low pressure (for example, about 22 ° C and about 2.3 MPa) which has been guided from the bottom portion 12 of the first distillation column 10 is passed through the second distillation flow channel. It is guided to the intermediate column portion 73 of the second distillation column 70.

The liquid component obtained by removing the methane component from the LNG (including the case where a small amount of the methane component is still present) is separated in the second distillation column 70 into a second gas component containing ethane as a main component and A second liquid component such as propane (having 3 or more carbon numbers).

A second gas component having a low temperature and a low pressure (for example, about -63 ° C and about 2.3 MPa) branched from the top 71 of the column is branched, and a gas component C generated by the branch flows in the second natural gas supply The passage is pressurized (about 6 MPa) via the second compressor 43 and further heated (for example, -41 ° C) via the second vaporizer to produce ethane-rich sNG which is supplied via the second natural gas supply portion 4.

Another gas component D produced by the branch is guided in the second reflux flow channel Leading to the fourth heat exchanger 24, performing a low-temperature condensation treatment (for example, about -63 ° C) by the coldness of the LNG guided from the third heat exchanger 23, and thereafter guiding it as a reflux liquid to the first The second distillation column is in the upper portion 74.

The second liquid component having high temperature and low pressure (for example, about 84 ° C and about 2.3 MPa) which has been taken out from the bottom portion 72 of the tower is guided to the fifth heat exchanger 25 in the liquefied petroleum gas supply flow passage, The coldness of the LNG guided from the fourth heat exchanger 24 is subjected to a low temperature treatment (for example, about 20 ° C), and thereafter supplied as an LPG via the liquefied petroleum gas supply portion 5.

Further, in the configuration example of the present invention, various liquid fuel gases such as "methane-rich gas and ethane-rich gas" (NG+sNG) and LPG containing NGL can be used according to the specification in the case where almost no external energy is required. The NG, NGL, sNG and LPG supplied from the respective flow channels are blended in an arbitrary manner to be efficiently prepared and supplied.

Specifically, as exemplified by the broken line of FIG. 6, the branch passage may be provided in the second natural gas supply flow passage, wherein the second natural gas is transferred from the second vaporizer 31 to the second natural gas supply portion 4, and is flowable with the natural gas supply a channel connection in which natural gas is transferred from the compressor 42 to the natural gas supply portion 2, thereby mixing a mixture of methane-rich NG and ethane-rich sNG, that is, "a gas having 1 and 2 carbon numbers as a main component" (NG+sNG) It may be supplied from the natural gas supply portion 2 or the second natural gas supply portion 4.

In FIG. 6, a case is illustrated in which the second natural gas is supplied from the second natural gas supply flow path to the natural gas supply flow path as shown by the arrow symbol; however, the present invention is not limited thereto, and it goes without saying that The invention includes the case of relative flow and the case where each of the two flow channels is supplied with a part to prepare a mixed gas. Further, in addition to mixing the prepared liquid fuel gases with each other, various liquid fuel gases may be mixed by LNG or mixed as a source material. For example, butane gas or an analog from outside the system is prepared and supplied with such gases.

In the case of using the fourth configuration example of the apparatus of the present invention, the LNG system having the composition exemplified in Table 1 above is supplied as a source material in order to verify the temperature (°C), pressure (MPa), and flow rate in each portion ( Kg/h) and composition (G/L: gas/liquid).

(i) verification results

When LNG (-150 ° C, 6.00 MPa) was supplied at 427,000 kg/h, the temperature, pressure, flow rate and composition in each of parts a to r2 in Fig. 7 were obtained, as exemplified in Table 5 below.

Here, a case is shown in which the entire amount of the liquid component guided from the bottom portion 12 of the distillation column 10 is guided to the second distillation column 70 (in Fig. 7, q1 = g2 and r1 = 0) However, a part of the liquid component may be supplied to the third heat exchanger 23 (r1=q1-g2>0 in Fig. 7), and supplied as NGL.

(ii) Subsequently, the input and output of energy in the apparatus of the present invention are verified against comparison with the first configuration example described above. As will be understood from Table 6 below, the following results have been obtained: When compared to the first configuration example, the amount of external energy supplied in the apparatus of the present invention is smaller, and the total amount is 858 kW (as in terms of power conversion).

The method of supplying a liquid fuel gas according to the fourth configuration example causes the liquid group guided from the bottom of the tower in the steps (1) to (8) of supplying the liquid fuel gas according to the first configuration example described above At least a portion of the fraction is directed to the second distillation column; an ethane-rich second natural gas is produced from the second gas component directed from the top of the second column of the second distillation column; and from the second distillation column Liquefied petroleum gas is prepared from the second liquid component guided from the bottom of the second tower. At this time, in place of the step (4) in this process, (4a) further guides the LNG guided from the third heat exchanger to the fourth heat exchanger after passing through the steps (1) to (3), And heating by releasing the coldness by heat exchange with the second gas component; (4b) guiding the LNG guided from the fourth heat exchanger to the fifth heat exchanger, and by Release its coldness by heating with heat exchange with the second liquid component; (4c) directing the LNG guided from the fifth heat exchanger into the vaporizer, and vaporizing by heating; and thereafter, passing The obtained product after the steps (5) to (8) is guided as a source material to the distillation column.

Further, a gas component C produced by the branching of the second gas component is adiabatically compressed by the second compressor and supplied as a heated and pressurized second natural gas; another component resulting from the branching of the second gas component a gas component D is condensed by a temperature decrease by LNG cooling in the step (4a) and is refluxed as a second reflux liquid to the upper portion of the second distillation column; and the second liquid component is subjected to the step (4b) The LNG cooling temperature in the middle is lowered and supplied as liquefied petroleum gas.

Specifically, a supply method including the following steps can be mentioned as an example. Here, in the following description, descriptions of constituent elements overlapping with the elements of the steps (1) to (8c) described above may be omitted, and each part of the apparatus of the present invention is used with FIG. 1 or FIG. The reference symbols indicated in the description. Further, the conditions exemplified in Table 2 above can be applied to various gas or liquid conditions; however, it goes without saying that the present invention is not limited thereto.

After passing through the above steps (1) to (3), the pressurized LNG stored in the supercooled state and serving as the source material is guided from the third heat exchanger 23.

(4a) The LNG supplied from the third heat exchanger 23 is guided into the fourth heat exchanger 24, and is heated by releasing its coldness by heat exchange with the gas component D guided from the tower top 71. For example, LNG having a temperature of about -71 ° C and a pressure of about 6 MPa is heated to about -51 ° C by releasing its coldness in heat exchanger 24 . At the same time, the temperature is about -63 ° C and the pressure is about 2.3 MPa. The gas component D was cooled to prepare a condensate of about -63 °C. The prepared condensate is introduced as a second reflux liquid into the upper portion 74 of the second distillation column.

(4b) directing the LNG guided from the fourth heat exchanger 24 into the fifth heat exchanger 25, and by releasing the coldness thereof via the bottom portion 72 of the tower from the second distillation column 70 The second liquid component is heat exchanged for heating. For example, LNG having a temperature of about -71 ° C and a pressure of about 6 MPa is heated to about -47 ° C by releasing its coldness in the fifth heat exchanger 25 . At the same time, a second liquid component having a temperature of about 84 ° C and a pressure of about 2.3 MPa was cooled to prepare and supply a liquefied petroleum gas of about 20 ° C.

(4c) The LNG guided from the fifth heat exchanger 25 is guided into the vaporizer 30 and vaporized by heating. For example, LNG having a temperature of about -47 ° C and a pressure of about 6 MPa is vaporized by releasing its coldness in the vaporizer 30 and heated to about 15 ° C.

In this process, the gaseous LNG guided from the vaporizer 30 is guided as a source material to the distillation column 10 through the above steps (5) to (8). The LNG self-guided to the distillation column 10 is supplied with methane-rich NG from the gas at the top of the column 11 from the top of the column of the distillation column 10 through the above steps (8a) to (8c), and from the bottom of the column from the distillation column 10. The liquid at the bottom of the tower 12 is supplied with NGL. Further, a part or the whole amount of the bottom liquid from the bottom portion 12 of the column is guided to the second distillation column 70 by the following steps (9a) to (9c), followed by the top of the second column from the second distillation column 70 71 the second gas at the top of the second column (second gas component) is prepared to prepare ethane-rich sNG, and the bottom liquid of the second column (second liquid) is guided from the bottom 72 of the second column of the second distillation column 70 Component) Preparation of LPG.

(9a) separating the LNG guided to the second distillation column 70 into a gas at the top of the second column rich in ethane and a component containing a carbon number greater than ethane (which may be referred to as "a component such as propane" hereinafter) The second component of the bottom of the main component of the liquid. Specifically, for example, in the second distillation column 70 having a pressure of about 2.3 MPa, a column top temperature of about -63 ° C and a column bottom temperature of about 84 ° C, the liquid LNG guided to the intermediate column portion 73 forms a downflow. And contacting it with an upflowing gas stream containing ethane and a component such as propane, heated and vaporized in the bottom 75 of the second column to increase the purity of components such as propane (liquid at the bottom of the second column). The upward flow formed in the column is brought into contact with the descending gas liquid mainly composed of the ethane-containing LNG and the ethane-rich reflux liquid to increase the purity of the ethane (the gas at the top of the second column).

(9b) The ethane-rich sNG system is prepared from the second column overhead gas directed from the top 71 of the second column. From the second column top 71, a second column overhead gas having a temperature of about -63 ° C and a pressure of about 2.3 MPa and containing, for example, 99.9% or more ethane is introduced, and about 20% of it is passed through the second compressor. 43 is compressed to, for example, about -61 ° C and about 6 MPa as the gas component C, and further heated by the second vaporizer 31 to form an ethane-rich sNG of, for example, about 35 ° C and about 6 MPa, which is supplied via the second natural gas supply portion 4 Supply. In the process, about 80% of the second column overhead gas is introduced as a gas component D into the fourth heat exchanger 24, and a second condensate of about -63 ° C is prepared in the fourth heat exchanger 24, and The prepared second condensate is directed as a second reflux to the upper portion 74 of the distillation column.

(9c) The LPG is prepared from a liquid at the bottom of the second column that is directed from the bottom 72 of the second column. From the second column bottom 72, a second bottoms liquid having a temperature of about 84 ° C and a pressure of about 2.3 MPa and containing, for example, 99.9% or more of components such as ethane is introduced, and via the fifth heat exchanger 25 The mixture was cooled to about 20 ° C to prepare LPG, which was supplied through the liquefied petroleum gas liquid supply portion 5. The desired product LPG can be supplied by the effective use of LNG. Further, in the apparatus of the present invention, although not illustrated in the drawings, on the one hand, not only the liquid from the bottom of the distillation column 10 but also the liquid from the bottom of the second column of the second distillation column 70 may be branched to supply the product (LPG). And on the other hand the bottom of the second tower The liquid can be heated via a reboiler (not illustrated in the drawings) to be introduced into the lower portion 75 of the second distillation column, thereby obtaining a high distillation function.

An overview of a fifth configuration example of the apparatus of the present invention will be shown in FIG. The apparatus of the present invention has a configuration in which, in the source material supply flow path of the fourth configuration example, the expander 41 is composed of expansion turbines 41a, 41b arranged in parallel; the LPG guided from the vaporizer 30 is branched to guide to expansion In each of the turbines 41a, 41b; the expansion turbine 41a is coupled to the compressor 42; and the expansion turbine 41b is coupled to the generator 60. Hereinafter, the common constituent elements of the first, second, and fourth configuration examples will be denoted by common reference numerals and reference symbols, and description thereof may be omitted.

The function under the optimum conditions of the apparatus of the present invention including the distillation column 10 and the second distillation column 70 can be supplied by NG and NGL according to fluctuations in the supply amount, composition, supply temperature, pressure, and the like of the LNG. The fluctuations in the supply amount, the supply temperature, the pressure, and the like are adjusted to adjust the operation amounts of the expansion turbines 41a and 41b and the operation amount of the compressor 42. Further, the connection of the expansion turbine 41b to the generator 60, the number of expansion turbines, and the connection of the plurality of expansion turbines to the compressor and the generator are the same as those of the second configuration example.

In the case of using the fifth configuration example of the apparatus of the present invention, the LNG having the composition exemplified in Table 1 above is supplied as a source material in order to verify the temperature (°C), pressure (MPa), and flow rate in each portion ( Kg/h) and composition (G/L: gas/liquid). When LNG (-150 ° C, 6.00 MPa) was supplied at 427,000 kg/h, the temperature in each of the portions s to v in Fig. 9 was obtained except for each of the portions a to r2 in Fig. 7. , pressure, flow rate and composition, as exemplified in Table 7 below. Further, a power generation amount of about 500 kW/h can be obtained from the generator 60 connected to the expansion turbine 42.

As shown above, various configuration examples have been described with reference to the respective explanatory views; however, the apparatus of the present invention is not limited thereto, and is constructed in a broad concept including a combination of constituent elements or a combination of related known constituent elements.

1‧‧‧Source material supply section

2‧‧‧ Natural Gas Supply Section

3‧‧‧ Natural gas supply part

10‧‧‧Distillation tower

11‧‧‧ top of the tower

12‧‧‧ bottom of the tower

13‧‧‧ Middle Tower Section

14‧‧‧ upper

15‧‧‧ lower

21‧‧‧First heat exchanger

22‧‧‧second heat exchanger

23‧‧‧ Third heat exchanger

30‧‧‧Vaporizer

41‧‧‧Expander

42‧‧‧Compressor

50‧‧‧ gas-liquid separator

Claims (7)

An apparatus for supplying a liquid fuel gas according to the present invention, comprising: guiding liquefied natural gas as a source material to a distillation column, and then preparing a methane-rich natural gas from a gas component guided from a top of the distillation column; Preparing a natural gas liquid from a liquid component guided from a bottom of the distillation tower, the apparatus having: a source material supply flow passage, wherein the supercooled pressurized liquefied natural gas is supplied as a source material through the source material supply portion, first a heat exchanger, a second heat exchanger, a third heat exchanger, a vaporizer, an expander, and the second heat exchanger and the gas-liquid separator are again introduced into the distillation column; the natural gas is supplied to the flow channel, wherein the gas is a gas component A produced by the branching of the component is supplied as the natural gas via a compressor and a natural gas supply portion connected to the expander; a reflux flow channel in which another gas component B is produced by branching of the gas component As a reflux liquid, being guided to the upper portion of the distillation column via the first heat exchanger; and a natural gas liquid supply flow passage, wherein the liquid component is The natural gas liquid is supplied through the third heat exchanger and the natural gas liquid supply portion, wherein in the first heat exchanger, the gas component B is performed by the coldness of the liquefied natural gas supplied from the source material supply portion Condensing to prepare the reflux liquid, in the second heat exchanger, the liquefied natural gas guided from the expander is subjected to low temperature condensation by the coldness of the liquefied natural gas guided from the first heat exchanger Preparing the source material, and in the third heat exchanger, the liquid component guided from the bottom of the tower is cooled by the temperature of the liquefied natural gas guided from the second heat exchanger. Reduced to prepare the natural gas liquid. The apparatus of claim 1, wherein the apparatus further comprises: a fourth heat exchanger and a fifth heat exchanger, which are provided downstream of the third heat exchanger in the source material supply flow passage; and a second distillation flow a channel in which a portion or all of the liquid component guided from the bottom of the column is directed to a second distillation column; a second natural gas is supplied to the flow channel, wherein the second column from the second distillation column is a gas component C generated by the branching of the second gas component is supplied as a second natural gas through the second compressor, the second vaporizer and the second natural gas supply portion; the second reflux flow channel, wherein Another gas component D produced by branching the second gas component guided from the top of the second column of the second distillation column is guided as a second reflux liquid to the second distillation column via the fourth heat exchanger And a liquefied petroleum gas supply flow passage, wherein the second liquid component guided from the bottom of the second tower of the second distillation column is supplied as liquefied petroleum gas through the fifth heat exchanger and the liquefied petroleum gas Distributing, wherein the gas component D is condensed in the fourth heat exchanger by the coldness of the liquefied natural gas guided from the third heat exchanger, thereby preparing the second reflux liquid, and The second liquid component guided from the bottom of the second tower is cooled in the fifth heat exchanger by the coldness of the liquefied natural gas guided from the fourth heat exchanger, thereby preparing the liquefied natural gas. . The apparatus of claim 1 or 2, further comprising: processing the entire amount of the liquefied natural gas supplied from the source material supply portion through the first to third heat exchangers and the vaporizer to a normal temperature plus Pressure state, followed by adiabatic expansion by an expander A temperature drop and a pressure drop occur, which are further condensed by direct introduction into the second heat exchanger, and separated by being guided into the gas-liquid separator, and then separated in the gas-liquid separator. The gas is introduced as the source material into the upper portion of the intermediate column of the distillation column, and the liquid separated in the gas-liquid separator is guided as the source material into the lower portion of the intermediate column of the distillation column. The apparatus of any one of claims 1 to 3, wherein the expander is comprised of a plurality of expansion turbines arranged in series; the liquefied natural gas guided from the vaporizer is branched to guide to the Each of the expansion turbines; one or more of the expansion turbines are coupled to the same number of the compressors; the other expansion turbines are coupled to the same number of generators; and the gas component A is directed to the compressions In the machine. The apparatus of any one of claims 1 to 4, further comprising a flow passage connected between the source material supply portion and the upper portion of the distillation column, such that when the apparatus is activated, A portion of the liquefied natural gas supplied from the source material supply portion is guided as the source material to the distillation column via the upper portion of the distillation column. A method of supplying a liquid fuel gas according to the present invention, comprising: directing liquefied natural gas as a source material to a distillation column, and then preparing a methane-rich natural gas from a gas component guided from a top of the distillation column; Preparing a natural gas liquid from a liquid component guided from a bottom of the distillation column, wherein a total amount of the supercooled pressurized liquefied natural gas is used as the source material via the source material supply portion, the first heat exchanger, and the second heat An exchanger, a third heat exchanger, a vaporizer, an expander, and the second heat exchanger and the gas-liquid separator are again introduced into the distillation column; (1) guiding the liquefied natural gas supplied from the source material supply portion To the first heat exchange And heating (by) releasing the coldness thereof by heat exchange with the gas component; (2) guiding the liquefied natural gas guided from the first heat exchanger into the second heat exchanger, And heating by releasing the coldness thereof by heat exchange with the liquefied natural gas guided from the expander; (3) guiding the liquefied natural gas guided from the second heat exchanger to the third heat In the exchanger, and heating by exchanging its coldness by heat exchange with the liquid component; (4) guiding the liquefied natural gas guided from the third heat exchanger into the vaporizer, and by Heating the vaporization; (5) guiding the liquefied natural gas guided from the vaporizer into the expander, and generating a pressure and a temperature decrease by adiabatic expansion; (6) guiding the self-expander from the expander The liquefied natural gas is again guided into the second heat exchanger, and is condensed by a temperature drop caused by the heat exchange in the step (2); (7) the content guided from the second heat exchanger The liquefied natural gas of the condensate is led to the gas-liquid separator for gas-liquid separation; (8) the gas-liquid separation a medium separated as a source material is introduced into an upper portion of the intermediate column of the distillation column, and a liquid separated in the gas-liquid separator is guided as a source material to a lower portion of the intermediate column of the distillation column; a gas component A produced by the branching of the gas component is adiabatically compressed in a compressor connected to the expander and supplied as heated and pressurized natural gas; another component resulting from the branching of the gas component a gas component B is condensed by a temperature decrease by the coldness of the liquefied natural gas in the step (1), and is refluxed as a reflux liquid to the upper portion of the distillation column; The liquid component is reduced in temperature by the coldness of the liquefied natural gas in the step (3), and is supplied as the natural gas liquid. The method of claim 6 wherein the method further comprises: directing a portion or all of the liquid component from the bottom of the column to the second distillation column; from the second distillation column Preparing a condensed ethane second natural gas by the second gas component guided from the top of the second column; preparing the liquefied petroleum gas from the second liquid component guided from the bottom of the second column of the second distillation column; Step (4), (4a) further guiding the liquefied natural gas guided from the third heat exchanger to the fourth heat exchanger after passing through the steps (1) to (3), and borrowing Heating by releasing its coldness by heat exchange with the second gas component; (4b) guiding the liquefied natural gas guided from the fourth heat exchanger to the fifth heat exchanger, and borrowing Cooling by releasing its coldness by heat exchange with the second liquid component; (4c) directing the liquefied natural gas guided from the fifth heat exchanger into the vaporizer, and vaporizing by heating; Thereafter, after passing through the steps (5) to (8), the resultant is introduced as the source material into the distillation column; a gas component C produced by branching of the second gas component is adiabatically compressed by a second compressor and supplied as a heated and pressurized second natural gas; another component resulting from the branching of the second gas component a gas component D by means of this step The coldness of the liquefied natural gas in (4a) is lowered in temperature to be condensed, and is returned as a second reflux liquid to the upper portion of the second distillation column; and the second liquid component is obtained by the step (4b) The coldness of the liquefied natural gas is lowered in temperature and supplied as the liquefied petroleum gas.