KR20160042851A - Working gas circulation type engine system and its operating method - Google Patents

Abstract

The present invention provides a working gas-circulating engine system which can suppress NOx emission. The working gas-circulating engine system (1A) comprises: an engine (3) which uses gas whose main component is argon as working gas; a circulation path (5) which connects an exhaust unit (3a) and an air supply unit (3b) of the engine (3) to circulate the working gas; and an oxygen supply device to supply oxygen to the engine (3). The oxygen supply device comprises a low temperature separation device (15) which separates air at a low temperature. An adsorption dehumidifying device (11) is formed on the circulation path (5) to remove moisture from exhaust gas emitted from the engine (3). A low pressure nitrogen supply line (17) discharges nitrogen separated by the low temperature separation device (15), and nitrogen induced from the low pressure nitrogen supply line (17) is used as regenerative gas of an adsorbent of the adsorption dehumidifying device (11).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a working gas recirculation type engine system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a working gas circulating engine system using an operating gas mainly composed of argon and a method of operating the same.

BACKGROUND ART [0002] There is known a working gas circulating type engine system in which an operating gas containing argon as a main component is circulated (Patent Document 1 and Patent Document 2). In the working gas circulation type engine system described in these patent documents, hydrogen is used as fuel. In such a working gas circulating type engine system, argon and oxygen are supplied to the combustion chamber in place of the air, so that argon functions as an expanding body (i.e., operating gas) due to heat generated by the combustion of hydrogen. The argon discharged from the engine circulates in the system and is supplied to the engine again with newly supplied oxygen. Thus, by using argon instead of nitrogen as the operating gas, the generation of nitrogen oxides (NOx) can be suppressed. Because argon is a mono-molecular gas and has a high specific heat ratio, it has the advantage of being able to build an engine system with excellent thermal efficiency.

Japanese Patent No. 3631891 Japanese Patent Application Laid-Open No. 2006-77639

However, diesel engines using heavy oil as a fuel have been widely used for a long time. However, due to rising prices of heavy fuel oil and falling prices of natural gas due to the shale gas revolution, gas engines using natural gas have been focused on .

For example, in a ship cycle engine to give propulsion power to a ship, gas engines using liquefied natural gas (LNG) as a fuel and natural gas as fuel can be used There is also a so-called Dual Fuel engine, which has been put into practical use.

As described above, in an engine using hydrogen or natural gas as a fuel, it is expected that the NOx emission amount is further reduced and the thermal efficiency of a further layer is improved.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a working gas circulation type engine system capable of suppressing NOx emission and a method of operating the same.

It is an object of the present invention to provide a working gas circulation type engine system having excellent thermal efficiency and a method of operating the same.

In order to solve the above problems, the working gas circulation type engine system and the operating method thereof according to the present invention employ the following means.

That is, an operating gas recirculation type engine system according to one aspect of the present invention includes: an engine using an argon-based gas as an operating gas; a circulation path for circulating the operating gas by connecting the exhaust portion and the supply portion of the engine; And an oxygen supply device for supplying oxygen to the engine, wherein the oxygen supply device is a hypo-cool separation device for separating and separating air.

Since the working gas is mainly composed of argon and has a smaller content of nitrogen than air, the amount of NOx generated from the engine can be reduced. The content of nitrogen in the operating gas is 15% or less, preferably 2% or less, more preferably 0% in the normal operating condition.

Oxygen is used as an oxidant for combustion in the engine. Oxygen is supplied to the engine from the oxygen supply. As the oxygen supply device, for example, when PSA (pressure swing adsorption) is used, there is a possibility that nitrogen is mixed into oxygen and a lot of nitrogen is supplied to the engine. Therefore, in the present invention, as the oxygen supply device, the use of a hypochlorous separation device that separates and separates air can produce oxygen having a higher purity than that of the PSA type, and the supply of nitrogen to the engine can be reduced as much as possible. Thus, the amount of NOx generated from the engine can be further suppressed. Particularly, in the engine system of the present invention, since the working gas is circulated, nitrogen may be accumulated in the circulating gas. Therefore, it is effective to use the hypochlorous separation device as the oxygen supply device.

As the fuel supplied to the engine, hydrocarbon gas fuel such as natural gas or hydrogen can be used.

The hypochlorous separation apparatus may be used for one loan, or may be a plurality. In the case of a plurality of engines, it is possible to cope with a partial engine load by reducing the number of engines.

In the working gas circulation type engine system, the circulation path is provided with a desiccation type dehumidifying device for removing moisture from the exhaust gas exhausted from the engine, and a first nitrogen supply line And nitrogen derived from the first nitrogen supply line may be used as a regeneration gas for the adsorbent of the adsorption dehumidifier.

When combustion is performed in the engine, moisture is contained in the exhaust gas. The moisture contained in the exhaust gas is removed by the adsorption dehumidifier formed in the circulation path, and the moisture-free working gas is sent to the engine and circulated.

In the adsorption dehumidifier, water is removed by adsorbing moisture in the exhaust gas to the adsorbent. In the present invention, when the adsorbent adsorbing moisture is regenerated, nitrogen separated by a hypochlorous separation apparatus is used. In the hypochlorite separating apparatus, since moisture in the air is removed before the separation of the cold air, the nitrogen separated by the hypochlorite separator becomes dry nitrogen. Since the adsorbent of the adsorption dehumidifier is regenerated by using this dry nitrogen, the regenerating performance of the adsorbent is improved and the dehumidification performance can be improved.

In the working gas circulation type engine system, the fuel supplied to the engine is a carbon-containing fuel, and the circulation path includes a turbine driven by exhaust gas discharged from the engine and power of the turbine, A supercharger having a compressor for compressing the exhaust gas, and an adsorption type carbon dioxide removing device formed on the downstream side of the compressor of the supercharger for removing carbon dioxide from the exhaust gas.

Since the fuel supplied to the engine is a carbon-containing fuel, carbon dioxide is contained in the exhaust gas burned in the engine. A carbon dioxide removing device is used to remove the carbon dioxide. In the present invention, adsorption is used as the carbon dioxide removing device, and carbon dioxide is removed from the exhaust gas by the adsorbent. Then, the adsorption-type carbon dioxide removing device was disposed on the downstream side of the compressor of the supercharger, so that the exhaust gas after being pressurized by the compressor was induced. As a result, the size of the adsorption tower containing the adsorbent can be reduced.

Examples of the carbon-containing fuel used as the fuel include hydrocarbon gases typically having 1 to 4 carbon atoms, and more specifically, methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), Butane (C ₄ H ₁₀ ), and the like.

It is preferable that a cooler for cooling the exhaust gas pressurized and heated by the compressor is formed because the adsorbent increases in adsorption power as the adsorbent lowers. Examples of such a cooler include a heat exchanger that performs heat exchange with water such as seawater.

The nitrogen separated by the centrifugal separator may be subjected to heat exchange with the exhaust gas pressurized by the compressor before the nitrogen is introduced into the adsorption dehumidifier. As a result, the nitrogen before being introduced into the adsorption dehumidifier can be heated by the compressed heat of the exhaust gas. Thereby, the regenerating performance of the adsorbent of the adsorption dehumidifier can be improved. By cooling the exhaust gas with the nitrogen gas, moisture in the exhaust gas can be removed as a drain, and the load of the adsorption dehumidifier can be reduced.

Wherein the working gas circulation type engine system is provided with a second nitrogen supply line for taking out nitrogen separated by the dew point separator and using nitrogen introduced from the second nitrogen supply line, A working gas and a heat exchanger for cooling the oxygen may be formed.

By increasing the gas density by cooling the working gas and the oxygen before being supplied to the engine by using the cold heat obtained by the hypothermic separator by introducing the nitrogen derived from the second nitrogen feed line into the heat exchanger, . Since the cooled working gas and oxygen are supplied to the engine, the compression start temperature in the cylinder can be lowered, and the cycle efficiency of the engine can be improved. The maximum temperature in the cylinder is reduced, so that the thermal load of the engine can be reduced.

The first nitrogen supply line described above and the second nitrogen supply line of the present invention may be used in common.

In the working gas circulation type engine system, a third nitrogen supply line is provided for extracting the nitrogen separated by the nitrogen separator after the nitrogen gas is pressurized by the nitrogen gas compressor. The nitrogen supplied from the third nitrogen supply line And a power generation device in which the turbine is driven to generate power may be formed.

The nitrogen separated by the centrifugal separator is used for power generation by the power generator. Therefore, the nitrogen separated by the centrifugal separator can be used effectively, and the energy efficiency as a whole system can be improved.

In the operating gas recirculation type engine system, the fuel supplied to the engine is liquefied gas, and the cooling / demulsing separator includes a heat exchanger that obtains cold heat from the liquefied gas before the liquefied gas is supplied to the engine You can.

Since the hypochlorous separation apparatus is provided with the heat exchanger for obtaining cold heat from the liquefied gas, the power of the hypochlorous separation apparatus can be reduced.

When the nitrogen separated by the hypothermic separator is pressurized by the nitrogen gas compressor as in the above-described invention, it can be used as a cold source as an aftercooler for cooling the pressurized nitrogen gas.

Examples of the liquefied gas include LNG (liquefied natural gas) and LPG (liquefied propane gas).

In the working gas recirculation type engine system, a fourth nitrogen supply line for taking out nitrogen separated by the centrifugal separator is provided, and the nitrogen supplied from the fourth nitrogen supply line and the boil off And a heat exchanger for heat-exchanging the gas to cool and boil the boil-off gas.

Since the boil-off gas is liquefied by using the nitrogen separated by the hypochlorite separator, there is no need for a special cold separator for re-liquefying the boil-off gas.

A method of operating a working gas circulation type engine system according to an aspect of the present invention is a method of operating a working gas circulation type engine system for circulating an operating gas containing argon as a main component by connecting an exhaust part and an air supply part of an engine, Characterized in that oxygen supplied to the engine is separated and separated from the air.

Since the working gas is mainly composed of argon and contains less nitrogen than air, the amount of NOx generated from the engine can be reduced. The content of nitrogen in the operating gas is 15% or less in a normal operating state.

Oxygen is used as an oxidant for combustion in the engine. When oxygen is supplied, for example, when PSA (Pressure Swing Adsorption) is used, there is a possibility that nitrogen is mixed in oxygen and a lot of nitrogen is supplied to the engine. Therefore, in the present invention, it is possible to reduce the supply of nitrogen to the engine as much as possible by producing oxygen having a purity higher than that of the PSA type or the like, by using oxygen obtained by separating air from the air. Thus, the amount of NOx generated from the engine can be further suppressed. Particularly, in the present invention, since nitrogen may be accumulated in the circulating gas for circulating the working gas, it is effective to use the low-temperature separation when supplying oxygen.

As the oxygen supplying device, the use of a low-temperature separating device for separating and separating the air from the air makes it possible to suppress the supply of nitrogen to the engine as much as possible, thereby suppressing the amount of NOx generated from the engine.

The cold heat is supplied to the heat exchanger by using the nitrogen derived from the hypothermic separator to cool the working gas and the oxygen supplied to the engine so that the thermal efficiency of the engine can be improved.

1 is a schematic structural view showing an operating gas circulation type engine system according to a first embodiment of the present invention.
2 is a schematic configuration diagram showing the adsorption type carbon dioxide removing device of FIG.
3 is a schematic structural view showing a working gas circulation type engine system according to a second embodiment of the present invention.
Fig. 4 is a schematic configuration diagram showing the dewatering apparatus of Fig. 3;
5 is a schematic configuration diagram showing a working gas circulation type engine system according to a third embodiment of the present invention.
6 is a schematic configuration diagram showing the dewatering apparatus of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig.

1 schematically shows an operating gas circulation type engine system (hereinafter simply referred to as " engine system ") 1A. The engine system 1A uses a gas containing argon as a main component as an operating gas and is applied to a ship cycle engine or the like which gives a propulsion force to a ship, for example.

The engine system 1A has an engine 3 and a circulation path 5 for connecting the exhaust part 3a and the supply part 3b of the engine 3 to circulate the working gas.

The engine 3 is, for example, a low-speed two-stroke cycle diesel engine. In the cylinder of the engine 3, CNG (compressed natural gas) obtained by gasifying LNG (liquefied natural gas) by pressure is injected as fuel. The CNG injected into the cylinder is, for example, at a temperature of 32 占 폚 and a pressure of 30 MPa.

A supercharger 7, a condenser 9, a desiccant type dehumidifying device 11 and an adsorption type carbon dioxide removing device 13 are formed in the circulation path 5.

The turbocharger 7 includes a turbine 7a driven by the exhaust gas discharged from the engine 3 and a compressor 7b for compressing the working gas by receiving power from the turbine 7a. The turbine 7a and the compressor 7b are connected by a common rotary shaft 7c so that the rotational force of the turbine 7a is transmitted to the compressor 7b.

The condenser 9 is formed on the downstream side of the turbine 7a. In the heat transfer pipe 9a in the condenser 9, seawater as a cooling medium is guided so that the exhaust gas guided into the condenser 9 is cooled. The exhaust gas discharged from the engine 3 by the condenser 9 is cooled, so that moisture in the exhaust gas condenses. The condensed water (LH ₂ O) is discharged out of the system (outside the circulation path 5) through the drain pipe 9b.

The adsorption type dehumidifying device (11) is disposed on the downstream side of the compressor (7b) to remove moisture in the exhaust gas. On the upstream side of the adsorption type dehumidifying device 11 is introduced a nitrogen gas introduced into the compressor 7b (nitrogen gas) by nitrogen introduced by a low-pressure nitrogen supply line (first nitrogen supply line) A first heat exchanger 19 for cooling the exhaust gas compressed by the first heat exchanger 19 and a second heat exchanger 21 for cooling the exhaust gas by seawater as a cooling medium, Is formed. The exhaust gas cooled by the first heat exchanger (19) and the second heat exchanger (21) is led to the adsorption dehumidifier (11). The moisture in the exhaust gas cooled and condensed by the first heat exchanger 19 and the second heat exchanger 21 is discharged from the drain pipe (not shown) out of the system (outside the circulation path 5).

The desiccant dehumidifier 11 is a desiccant rotor which is made of PSA (Pressure Swing Adsorption) or TSA (Temperature Swing Adsorption) and has an adsorbent such as alumina or silica gel carried thereon. The heating gas for regenerating the adsorbent that has adsorbed the moisture in the exhaust gas (that is, for desorbing moisture from the adsorbent and returning the adsorbent to its original adsorbable state) is introduced from the low-pressure nitrogen supply line 17 and supplied to the first heat exchanger 19, a heated nitrogen gas is used by cooling the exhaust gas.

The exhaust gas from which moisture has been removed by the adsorption dehumidifying device (11) is led to the adsorption type carbon dioxide removing device (13) through the circulation path (5).

The adsorption type carbon dioxide removing device 13 is of the PSA (Pressure Swing Adsorption) type, and removes carbon dioxide contained in the exhaust gas.

Fig. 2 shows details of the adsorption type carbon dioxide removing device 13, and has two adsorption towers 23a and 23b on the upstream side and the downstream side. Each of the adsorption towers 23a and 23b is filled with a predetermined adsorbent such as a zeolite-based adsorbent. The first adsorption tower 23a on the upstream side and the second adsorption tower 23b on the downstream side are plural in order to perform batch processing. On the upstream side of the first adsorption tower 23a, a first compressor 25a for increasing the exhaust gas introduced from the left side through the circulation path 5 and a second compressor 25b disposed on the downstream side of the first compressor 25a The first cooler 27a is formed. In the first adsorption tower 23a, a first heater 29a for regenerating the adsorbent adsorbing carbon dioxide is formed. An outlet pipe 31 is connected to the first adsorption tower 23a and the exhaust gas after the carbon dioxide is removed from the outlet pipe 31 is guided to the circulation path 5. [ Since the exhaust gas discharged from the outlet pipe 31 is already free of carbon dioxide and moisture, it is a working gas containing argon as a main component.

A first surge tank 35a is connected to the first adsorption tower 23a via a first desorption pipe 33a. A first vacuum pump 37a is formed in the first removing pipe 33a. Is heated by the first heater (29a) described above, and the inside of the first adsorption tower (23a) is decompressed by the first vacuum pump (37a) to desorb the carbon dioxide adsorbed by the adsorbent.

The first surge tank 35a is connected to the second adsorption tower 23b via the second compressor 25b and the second cooler 27b. In the second adsorption tower 23b, a second heater 29b for regenerating the adsorbent adsorbing carbon dioxide is formed. A first return pipe 39a and a second return pipe 39b are connected to the second adsorption tower 23b.

The first return pipe 39a is connected to the downstream side of the first cooler 27a and to the upstream side of the first adsorption tower 23a. A third compressor 25c and a third cooler 27c are formed in the first return pipe 39a. The first return pipe 39a is configured to return the gas after the carbon dioxide is adsorbed by the second adsorption tower 23b to the first adsorption tower 23a. Thereby, the argon gas accompanying the carbon dioxide can be reused without discharging it out of the system.

The second return pipe 39b is connected to the first surge tank 35a. In the second return pipe 39b, a pressure reducer 25d and a third heater 27d are formed. And the second return pipe 39b is used to return the gas displaced in the second adsorption tower 23b to the first surge tank 35a.

The second adsorption tower 23b is connected to the second surge tank 35b via the second desorption line 33b. And a second vacuum pump 37b is formed in the second removing pipe 33b. Is heated by the second heater (29b) described above, and the inside of the second adsorption tower (23b) is decompressed by the second vacuum pump (37b) to desorb the carbon dioxide adsorbed by the adsorbent. The desorbed gas is temporarily stored in the second surge tank 35b, and then discharged from the carbon dioxide discharge pipe 41 to the outside of the system. The concentration of carbon dioxide emitted is about 99%.

The second surge tank 35b is connected to the second adsorption tower 23b via the third return pipe 39c. In the third return pipe 39c, a fifth compressor 25e and a fourth cooler 27e are formed. The gas (principally carbon dioxide) derived from the third return pipe 39c is used as a gas for replacing the inside of the second adsorption tower 23b.

The working gas discharged from the first adsorption tower 23a through the outlet pipe 31 is returned to the engine 3 through the circulation path 5 as shown in Fig.

The hypochlorous separation apparatus 15 separates oxygen, argon and nitrogen from air outside the system. The hypochlorous separation apparatus 15 is provided with an adsorption tower 46 for removing moisture and carbon dioxide from the air taken in from the outside of the system, a compressor for compressing the air from which moisture and carbon dioxide have been removed, and an expansion turbine for expanding the compressed air A refrigerator 48 and a rectification tower 50 for separating low-temperature air derived from the refrigerator 48 by cooling and cooling.

The oxygen separated in the rectifying column 50 is boosted by the oxygen liquid pump 52 and then supplied to the engine 3 through the oxygen supply passage 54. [ The oxygen supplied to the engine 3 is used as an oxidizing agent for burning CNG.

Nitrogen separated in the rectification column 50 is led to the first heat exchanger 19 through the low-pressure nitrogen supply line 17. [ Nitrogen derived from the low-pressure nitrogen supply line 17 becomes dry nitrogen because moisture is removed from the adsorption tower 46 of the hypochlorous separation apparatus 15. [ In the first heat exchanger (19), the nitrogen cooled by the exhaust gas derived from the compressor (7b) is led to the adsorption dehumidifier (11) and used as a regeneration gas, and then discharged out of the system.

Although not shown, argon separated from the rectification column 50 is also supplied to the engine 3 so as to compensate for a shortage of argon in the working gas flowing in the circulation path 5.

Next, the operation of the above-described engine system 1A will be described. The temperatures, pressures, and composition ratios shown below are only examples.

Oxygen separated from air outside the system is supplied to the engine 3 via the circulation path 5 and an operating gas containing argon as a main component is supplied through the circulation path 5. [ For the engine, CNG, which is fuel, is supplied from an LNG storage tank, not shown.

Combustion is performed in the cylinder of the engine 3 by the CNG, oxygen, and working gas supplied to the engine 3. [ The temperature of the CNG supplied to the engine 3 is 32 DEG C, the pressure of CNG is 30 MPa, the temperature of oxygen is 32 DEG C, the pressure of oxygen is 225 GPG (gauge pressure; , The working gas pressure is 225 ㎪G. The composition ratio of the operating gas is 76.0% of argon, 23.8% of oxygen and 0.2% of nitrogen. When the composition ratio of gas is expressed as a percentage, it means volume% (the same applies hereinafter).

The combustion gas that has been burned in the engine 3 is discharged as exhaust gas from the exhaust portion 3a. The temperature of the exhaust gas discharged from the exhaust part 3a is 330 占 폚 and the pressure is 183 ㎪G.

The exhaust gas discharged from the exhaust part 3a is guided to the turbine 7a of the turbocharger 7 and expanded. The temperature of the exhaust gas after expansion is 170 deg. C, and the pressure is 0 deg. The rotational force obtained by the turbine 7a rotatively drives the compressor 7b through the rotating shaft 7c.

The exhaust gas expanded by the turbine 7a is led to the condenser 9 and cooled by seawater at 25 DEG C, so that moisture in the exhaust gas condenses. The temperature of the exhaust gas after leaving the condenser 9 is 32 deg. C and the pressure is 0 deg.

The exhaust gas after leaving the condenser 9 is guided to the compressor 7b of the turbocharger 7 and pressurized. The temperature of the exhaust gas after the pressure increase is 255 deg. C and the pressure is 225 deg.

The exhaust gas after being pressurized by the compressor 7b is cooled by the nitrogen introduced from the cold separator 15 through the low-pressure nitrogen feed line 17 in the first heat exchanger 19. The temperature of the nitrogen before heat exchange with the first heat exchanger 19 is 32 deg. C, the pressure is 0 deg. G, the temperature of the nitrogen after heat exchange is 200 deg. C, and the pressure is 0 deg.

The exhaust gas after being cooled by the first heat exchanger (19) is again cooled by the second heat exchanger (21). In the second heat exchanger 21, it is cooled by seawater at 25 ° C, whereby the exhaust gas is cooled to 25 ° C. The exhaust gas is cooled by the first heat exchanger (19) and the second heat exchanger (21), whereby moisture in the exhaust gas is removed as drain water. The drain number is discharged to the outside of the system through a pipeline not shown.

The exhaust gas after being cooled by the first heat exchanger (19) and the second heat exchanger (21) is led to the adsorption dehumidifier (11) to remove moisture again. The moisture in the exhaust gas is led to the desiccant rotor of the adsorption dehumidifier 11 and is removed by the adsorbent formed on the desiccant rotor. For the regeneration of the adsorbent formed in the desiccant rotor, nitrogen gas heated to 200 DEG C by the first heat exchanger (19) is used. The temperature of the exhaust gas after leaving the adsorption dehumidifier 11 is 25 ° C and the pressure is 225 GPa.

The exhaust gas from which the moisture in the exhaust gas is removed by the adsorption-type dehumidifying device (11) passes through the circulation path (5) and the carbon dioxide is removed by the adsorption type carbon dioxide removing device (13).

2, the exhaust gas guided to the adsorption-type carbon dioxide removing device 13 is cooled by the first cooler 27a after being raised by the first compressor 25a, and is supplied to the first adsorption tower 23a . In the first adsorption tower 23a, carbon dioxide in the exhaust gas is adsorbed by the adsorbent charged in the first adsorption tower 23a, and carbon dioxide is removed from the exhaust gas. The exhaust gas after the carbon dioxide is removed is led to the circulation path 5 shown in FIG. 1 through the outlet pipe 31. Since the exhaust gas derived from the outlet pipe 31 is free of moisture and carbon dioxide, it becomes a working gas containing argon as a main component.

When the first adsorption tower 23a is detached, the inside of the first adsorption tower 23a is depressurized by the first vacuum pump 37a and the inside of the first adsorption tower 23a is depressurized by the first heater 29a. . As a result, the carbon dioxide adsorbed on the adsorbent is desorbed, and the desorbed carbon dioxide is led to the first surge tank 35a through the first desorption pipe 33a. The first desorption gas led to the first surge tank 35a contains carbon dioxide as a main component, but since argon gas is contained in a small amount, argon gas is taken out from the desorbed gas by the following operation.

The first desorbing gas in the first surge tank 35a is raised by the second compressor 25b, cooled by the second cooler 27b, and guided to the second adsorption tower 23b. In the second adsorption tower 23b, carbon dioxide in the first desorption gas is adsorbed by the adsorbent charged in the second adsorption tower 23b to remove carbon dioxide from the first desorption gas. After the carbon dioxide has been removed, argon is the main constituent. After the gas is pressurized by the third compressor 25c through the first return pipe 39a, the gas is cooled by the third cooler 27c, As shown in Fig. As a result, it is possible to reduce the exhaustion of argon gas accompanying the carbon dioxide in the first desorption gas to the outside of the system.

After the adsorption process is performed in the second adsorption tower 23b, the gas replacement in the second adsorption tower 23b is performed. Specifically, the second desorbing gas stored in the second surge tank 35b is raised by the fifth compressor 25e through the third return pipe 39c, cooled by the fourth cooler 27e And is led to the second adsorption tower 23b. Thus, the inside of the second adsorption column 23b is gas-displaced by the second desorption gas introduced into the second adsorption tower 23b, and the gas after the gas replacement passes through the second return pipe 39b to the decompressor 25d And is then heated by the third heater 27d and returned to the first surge tank 35a.

After the gas replacement step is performed, the second adsorption tower 23b is detached. That is, the inside of the second adsorption tower 23b is depressurized by the second vacuum pump 37b, and the inside of the second adsorption tower 23b is heated by the second heater 29b. As a result, the carbon dioxide adsorbed on the adsorbent is desorbed, and the desorbed carbon dioxide is led to the second surge tank 35b through the second desorbing pipe 33b. The second desorption gas led to the second surge tank 35b is discharged to the outside of the system through the carbon dioxide discharge pipe 42. [ The carbon dioxide concentration of the second desorption gas is 99%.

The working gas from which the carbon dioxide has been removed by the adsorption type carbon dioxide removing device 13 is guided to the supply portion 3b of the engine 3 through the circulation path 5 as shown in Fig.

As described above, according to the present embodiment, the following operational effects are exhibited.

As the oxygen supply device for supplying oxygen to the engine 3, a cooler / liquid separator 15 for separating the air outside the system from the system is used. Since the hypochlorous separation apparatus can produce oxygen of high purity, the supply of nitrogen to the engine can be reduced as much as possible, and the amount of NOx generated from the engine can be suppressed. On the other hand, if the oxygen supply device is, for example, a pressure swing adsorption (PSA) type, the nitrogen concentration in the oxygen is higher than that in the hypochlorous separation device, and nitrogen may be supplied to the engine. In particular, in the engine system 1A of the present embodiment, nitrogen may be accumulated in the circulating gas in order to circulate the working gas, and therefore it is effective to use the psychrometric separator 15 as the oxygen supply device.

Nitrogen recovered from the adsorbent dehumidifier 11 is regenerated by the nitrogen separator 15. Since the moisture in the air is removed from the adsorption tower 46 in the hypochlorous separation unit 15 before nitrogen separation, the nitrogen separated by the hypochlorous separation unit 15 becomes dry nitrogen. Since the adsorbent of the adsorption dehumidifier 11 is regenerated by using this dry nitrogen, the regenerating performance of the adsorbent is improved and the dehumidification performance can be improved.

The exhaust gas pressurized by the compressor 7b is exchanged with the first heat exchanger 19 before the nitrogen separated by the hypothermic separator 15 is led to the adsorption dehumidifier 11. [ As a result, the nitrogen before being introduced into the adsorption type dehumidifying device (11) can be heated by the compressed heat of the exhaust gas, and the regenerating performance of the adsorbent can be further improved.

The moisture in the exhaust gas can be removed as a drain by cooling the exhaust gas with the nitrogen gas by the first heat exchanger 19, so that the load of the adsorption dehumidifier 11 can be reduced.

The adsorption type carbon dioxide removing device 13 is disposed on the downstream side of the compressor 7b of the turbocharger 7 so that the exhaust gas after being pressurized by the compressor 7b is induced. As a result, the size of the adsorption tower containing the adsorbent can be reduced.

Since the adsorbent increases in adsorption power as the temperature of the adsorbent increases, the exhaust gas pressurized and raised by the compressor 7b is cooled by the first heat exchanger 19 and the second heat exchanger 21, and then is returned to the adsorption type carbon dioxide removing device 13 . Thus, the adsorption performance in the adsorption type carbon dioxide removing device (13) can be improved.

[Second Embodiment]

Next, a second embodiment of the present invention will be described with reference to Figs. 3 and 4. Fig. The present embodiment differs from the first embodiment in that several configurations are added. Therefore, the components common to those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

As shown in Fig. 3, the engine system 1B of the present embodiment is provided with an air-supply cooling heat exchanger 56 for cooling the oxygen and working gas supplied to the engine 3.

An oxygen supply path 54 and a circulation path 5 are connected as a cooled side to the air supply cooling heat exchanger 56. A low pressure nitrogen supply line (second nitrogen supply line) 17 and a high pressure nitrogen And a supply line (second nitrogen supply line) 18 is connected.

From the low-pressure nitrogen supply line 17, nitrogen having a temperature of -40 DEG C and a pressure of 0 DEG C was induced. From the high-pressure nitrogen supply line 18, nitrogen having a temperature of -40 DEG C and a pressure of 199 DEG C Lt; / RTI > The temperature of the nitrogen obtained from the low-pressure nitrogen supply line 17 and the high-pressure nitrogen supply line 18 is adjusted in accordance with the refrigeration ability of the refrigerator 48 of the hypochlorous separation unit 15.

Oxygen and working gas are cooled to 0 DEG C by the air-cooling heat exchanger 56 and supplied to the engine 3.

The nitrogen introduced by the low-pressure nitrogen supply line 17 is heated to -10 DEG C by the air-cooling heat exchanger 56, and then is led to the first heat exchanger 19. [ The point that the nitrogen passing through the low-pressure nitrogen supply line 17 is used as the regeneration gas of the adsorption-type dehumidifier 11 after being led to the first heat exchanger 19 is the same as that of the first embodiment.

Nitrogen introduced by the high-pressure nitrogen supply line (third nitrogen supply line) 18 is heated to -10 ° C by the air supply cooling heat exchanger 56, and then is led to the third heat exchanger 22. The nitrogen after cooling the exhaust gas passing through the circulation path 5 by the third heat exchanger 22 is led to the cold / The cold / hot water generator 60 recovers the cold heat obtained from the cold / cool water separator 15 and generates electric power, and includes a generator turbine 60a and a generator 60b driven by the generator turbine 60a . Nitrogen induced by the high-pressure nitrogen supply line 18 drives the power generation turbine 60a.

Nitrogen introduced into the high-pressure nitrogen supply line 18 is pressurized by the nitrogen gas compressor 62 provided in the dewatering apparatus 15. Nitrogen raised by the nitrogen gas compressor (62) is cooled by the nitrogen gas cooler (64). As the cooling source of the nitrogen gas cooler 64, LNG led from the LNG tank (not shown) through the LNG supply pipe 66 is used. The LNG fed to the cold separator 15 by the LNG feed pipe 66 is cooled by the nitrogen gas cooler 64 and then heated to CNG by a device not shown, To the engine (3).

Fig. 4 shows the details of the dewatering apparatus 15 shown in Fig.

The hypochlorous separation apparatus 15 is provided with a filter 70 for removing dust and the like from the air taken in from outside the system and a main air compressor 72 for compressing the air. The air compressed by the main air compressor 72 is led to the adsorption tower 46 after being cooled by the air cooler 74. Moisture and carbon dioxide in the air are removed from the adsorption tower 46. A part of the air in which moisture and carbon dioxide are removed is guided to the sub air compressor 48a and compressed and the other air is led to the heat exchanger 78 through the air bypass passage 76. [ The air compressed by the sub air compressor 48a is cooled by the heat exchanger 78 and thereafter decompressed by the expansion valve 80 and merged with the air of the air bypass passage 76. [ The combined air is led to the lower tower 50a of the rectification column 50. [

A part of the air flowing through the air bypass passage 78 is led to the expansion turbine 48b of the refrigerator 48 through the pipe 82 for expanded air. Air which has been inflated by the expansion turbine 48b to become cryogenic (for example, -186 占 폚) is led to the upper tower 50b of the rectification column 50. [

In the rectifying column 50, oxygen, argon, and nitrogen are separated from the air. Liquid air is stored in the bottom portion of the lower tower 50a of the rectification tower 50 and liquid oxygen is stored in the lower portion of the upper tower 50b of the rectification tower 50. [ The liquid nitrogen (for example, -193 DEG C) condensed by the nitrogen condenser 84 is directed upward of the upper column 50b of the rectification column 50 to cool the column.

The nitrogen gas taken out from the top of the upper tower 50a of the rectifying column 50 by the low pressure nitrogen supply line 17 is led to the above described supply air cooling heat exchanger 56 .

The nitrogen gas taken out by the high-pressure nitrogen supply line 18 from the top of the upper tower 50a of the rectification column 50 is pressurized by the nitrogen gas compressor 62 and then supplied to the LNG by the nitrogen gas cooler 64 Lt; / RTI > The nitrogen cooled by the nitrogen gas cooler 64 passes through the high-pressure nitrogen supply line 18 and is led to the above-described supply air cooling heat exchanger 56 (see FIG. 3).

The liquid oxygen stored in the lower part of the upper tower 50b of the rectifying column 50 is taken out as liquid and raised by the oxygen liquid pump 52 and then passes through the oxygen supply path 54 And is directed to the air supply cooling heat exchanger 56 (see FIG. 3).

As described above, according to the present embodiment, the following operational effects are exhibited.

Nitrogen supplied from the low-pressure nitrogen supply line 17 and the high-pressure nitrogen supply line 18 is led to the air-supply cooling heat exchanger 56 to supply the engine 3 with cold heat obtained by the cold- And the working gas and oxygen before cooling were cooled. Thus, by increasing the gas density of the working gas and the oxygen, the performance of the engine 3 can be improved. Since the cooled working gas and oxygen are supplied to the engine 3, the compression start temperature in the cylinder can be lowered and the cycle efficiency of the engine 3 can be improved. The maximum temperature in the cylinder is reduced, so that the thermal load of the engine 3 can be reduced. Either one of the low-pressure nitrogen supply line 17 and the high-pressure nitrogen supply line 18 may be used as a heat source for cooling the air supply cooling heat exchanger 56.

Nitrogen gas compressor 62 in the hypochlorous separation unit 15 and high-pressure nitrogen is supplied to the cold / hot water generator 60 through the high-pressure nitrogen supply line 18 to generate electricity. As a result, the energy efficiency as a whole of the engine system 1B can be improved. Since the nitrogen gas taken out of the rectification column 50 is compressed by the nitrogen gas compressor 62, the compression power of the nitrogen gas can be reduced.

The LNG used as the fuel of the engine 3 is led to the nitrogen gas cooler 64 and the nitrogen gas heated by the nitrogen gas compressor 62 is cooled. As a result, the cold heat of the LNG can be effectively used, and the energy efficiency of the entire engine system 1B can be improved. The cold heat of the LNG can also be used for other parts of the hypothermic separator 15 and may be used as a heat source for the heat exchanger 78 for cooling compressed air, for example.

Liquid oxygen is taken out as liquid from the rectification column 50 and the pressure is increased by the liquid pump 52 for oxygen. Thereby, the compression power can be reduced as compared with the case of compressing gaseous oxygen.

[Third embodiment]

Next, a third embodiment of the present invention will be described with reference to Figs. 5 and 6. Fig. This embodiment differs from the second embodiment in that a device for liquefying the boil-off gas is provided. Therefore, the same components as those of the second embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

As shown in Fig. 5, the engine system 1C of the present embodiment is provided with a BOG liquefier 85 for liquefying the boil-off gas. The BOG liquefier 85 liquefies the boil-off gas generated in the LNG storage tank (not shown) and returns it to the LNG storage tank. The BOG liquefier 85 includes a BOG liquefaction tank 87 and a BOG liquefaction heat exchanger 89.

A boiling off gas derived from the LNG storage tank is introduced into the vapor phase portion of the BOG liquefaction tank 87 through the BOG supply pipe 91. The boil off gas introduced into the BOG liquefaction tank 87 is led to the BOG liquefaction heat exchanger 89 through the BOG extraction pipe 93. In the BOG liquefied heat exchanger 89, the boil-off gas is cooled and liquefied by the nitrogen gas, for example, -170 DEG C derived from the low temperature nitrogen supply line (fourth nitrogen supply line) The liquefied BOG (i.e., LNG) is conveyed to the BOG liquefaction tank 87 through the LNG return pipe 97. As shown in Fig. 6, the nitrogen gas is taken out from the top of the rectifying column 50. The nitrogen gas after the boiling off gas is cooled and liquefied by the BOG liquefied heat exchanger 89 is led to the nitrogen gas compressor 62 and is supplied to the air supply cooling heat exchanger 56 and the cold / (60).

The LNG stored in the bottom portion of the BOG liquefaction tank 87 is led to the LNG storage tank by a pipe not shown.

As described above, according to the present embodiment, the following operational effects are exhibited.

Off gas is liquefied by the BOG liquefied heat exchanger 89 using nitrogen at a low temperature separated by the hypochlorite separator 15. This makes it unnecessary to separate the leachate gas for re-liquefaction of boiling off gas . Therefore, the energy efficiency as a whole of the engine system 1C can be improved.

The present invention is not limited to the above-described embodiments. In the above-described embodiments, LNG is used as the fuel to be supplied to the engine 3, but the present invention is not limited to this. For example, instead of LNG, for being even to the use of hydrogen, and the other carbon-containing fuel, for example methane (CH _4), ethane (C ₂ H _6), propane (C ₃ H _8), butane (C ₄ H ₁₀ ) may be used as the hydrocarbon gas.

In each of the above-described embodiments, a single hypothermal separation apparatus 15 is used. However, the present invention is not limited to this, and a plurality of hypochlorous separation apparatuses 15 may be used. In the case of using a plurality of hypochlorous separation apparatuses 15, it is possible to cope with the partial load of the engine 3 by reducing the number of operations.

1A: Working gas circulating engine system
3: engine
3a:
3b:
5: Circulation path
7: supercharger
7a: Turbine
7b: Compressor
7c:
9: Condenser
9a:
9b: drain pipe
11; Adsorption dehumidifier
13: Absorption type carbon dioxide removal device
15: Cold separation device (oxygen supply device)
17: Low-pressure nitrogen supply line (first nitrogen supply line, second nitrogen supply line)
18: High pressure nitrogen supply line (second nitrogen supply line, third nitrogen supply line)
19: first heat exchanger
21: Second heat exchanger
22: Third heat exchanger
23a: first adsorption tower
23b: second adsorption tower
25a: first compressor
25b: a second compressor
25c: third compressor
25d: Pressure reducer
25e: fifth compressor
27a: first cooler
27b: second cooler
27c: third cooler
27d: third heater
27e: fourth cooler
29a: First heater
29b: second heater
31: Exit piping
33a: First take-off pipe
33b: Second take-off pipe
35a: First surge tank
35b: Second surge tank
37a: first vacuum pump
37b: second vacuum pump
39a: first return pipe
39b: second return pipe
41: Carbon dioxide discharge piping
46: Adsorption tower
48: Freezer
50: rectification tower
50a: Lower tower
50b: upper tower
52: liquid pump for oxygen
54: oxygen supply path
56: Supply air cooling heat exchanger
60: Cooling /
62: Nitrogen gas compressor
64: Nitrogen gas cooler
66: LNG supply piping
68: CNG supply piping
70: Filter
72: main air compressor
74: air cooler
76: air bypass flow
78: heat exchanger
80: Expansion valve
82: Piping for expanded air
85: BOG Liquefaction Device
87: BOG liquefaction tank
89: BOG Liquefied Heat Exchanger
91: BOG supply piping
93: BOG outlet piping
95: low temperature nitrogen supply line (fourth nitrogen supply line)
97: LNG return piping

Claims (6)

An engine using an argon-based gas as a working gas,
A circulation path for circulating the working gas by connecting the exhaust part and the supply part of the engine,
And an oxygen supply device for supplying oxygen to the engine, wherein the operating gas circulation type engine system comprises:
Wherein the oxygen supply device is a hypo-chilling separator for separating and separating air,
A dehumidification device for removing moisture from the exhaust gas exhausted from the engine is formed in the circulation path,
And a first nitrogen supply line for taking out the nitrogen separated by the hypothermic separation apparatus,
Nitrogen derived from the first nitrogen supply line is used as a regeneration gas for the adsorbent of the adsorption dehumidifier,
The fuel supplied to the engine becomes a carbon-containing fuel,
In the circulation path,
A supercharger having a turbine driven by exhaust gas discharged from the engine and a compressor for obtaining power of the turbine and compressing the working gas;
An adsorption type carbon dioxide removing device formed on the downstream side of the compressor of the supercharger for removing carbon dioxide from the exhaust gas,
The exhaust gas that has been pressurized by the compressor is cooled by nitrogen introduced from the first nitrogen supply line and the cooled exhaust gas is introduced into a dehumidifying device for adsorption, To the carbon dioxide removal device. The method according to claim 1,
And a second nitrogen supply line for taking out the nitrogen separated by the hypochlorite separator,
And a heat exchanger for cooling the working gas and the oxygen supplied to the engine is formed using nitrogen derived from the second nitrogen supply line. The method according to claim 1,
And a third nitrogen supply line for removing the nitrogen separated by the hypochlorite separator after being pressurized by a nitrogen gas compressor,
And a power generation device in which a turbine is driven by the nitrogen supplied from the third nitrogen supply line to generate electric power is formed. The method according to claim 1,
The fuel supplied to the engine becomes liquefied gas,
Wherein the cool-air separating device includes a heat exchanger for obtaining cold heat from the liquefied gas before the liquefied gas is supplied to the engine. The method according to claim 1,
And a fourth nitrogen supply line for taking out the nitrogen separated by the hypochlorite separator,
And a heat exchanger for exchanging heat between the nitrogen supplied from the fourth nitrogen supply line and the boil-off gas generated from the storage tank of the liquefied gas to cool and boil the boil-off gas. A method of operating a working gas circulating engine system for circulating an operating gas containing argon as a main component by connecting an exhaust part and an oil supply part of an engine,
The engine is supplied with oxygen separated from the air by air-cooling separation device,
In the circulation path in which the operating gas circulates, water is removed from the exhaust gas exhausted from the engine by the adsorption dehumidifier,
The nitrogen separated by the hypothermic separation apparatus is taken out to the first nitrogen supply line,
Nitrogen derived from the first nitrogen supply line is used as a regeneration gas for the adsorbent of the adsorption dehumidifier,
The fuel supplied to the engine becomes a carbon-containing fuel,
In the circulation path,
A supercharger having a turbine driven by exhaust gas discharged from the engine and a compressor for obtaining power of the turbine and compressing the working gas;
An adsorption type carbon dioxide removing device is formed on the downstream side of the compressor of the supercharger,
The adsorbing carbon dioxide removing device removes carbon dioxide from the exhaust gas,
The exhaust gas that has been pressurized by the compressor is cooled by nitrogen introduced from the first nitrogen supply line and the cooled exhaust gas is introduced into a dehumidifying device for adsorption, A method of operating a working gas recirculating engine system leading to a carbon dioxide removing device.

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