JP5221087B2 - Hydrocarbon recovery system, degassing apparatus used therefor, and hydrocarbon recovery method. - Google Patents

Description

  The present invention relates to a hydrocarbon recovery system, a degassing device used therefor, and a hydrocarbon recovery method.

  Tankers and tank trucks that carry crude oil, various petroleum products, and semi-finished products in tanks are usually loaded with crude oil, various petroleum products, semi-finished products, and then mainly nitrogen and carbon dioxide for safety reasons. By introducing gas as a component, the oxygen concentration in the tank is adjusted to a concentration outside the explosion range. When crude oil, various petroleum products, and semi-finished products are loaded into this tank again, the gas in the tank is discharged out of the tank.

  Exhaust gas discharged from such tanks usually contains several percent to several tens percent (volume basis) of hydrocarbon compounds generated from the crude oil, various petroleum products or semi-finished products left immediately before. ing. If such exhaust gas is released into the atmosphere, it may cause environmental problems such as air pollution, and may be a safety problem. Moreover, burning these exhaust gases into the atmosphere not only wastes energy resources, but also increases the emission of air pollutants such as nitrogen oxides.

Therefore, it is known to recover the hydrocarbon compound by contacting the exhaust gas containing the hydrocarbon compound and the absorbing liquid, for example, by contacting the exhaust gas with the crude oil stored in the tank, A system for recovering hydrocarbon compounds in crude oil has been proposed (see, for example, Patent Document 1).
JP 2007-099817 A

  However, in the conventional hydrocarbon compound recovery system, if the hydrocarbon compound is absorbed in the absorption liquid, it immediately reaches saturation, so the recovered liquid that has absorbed the hydrocarbon compound is frequently replaced with a new absorption liquid. Or the collected liquid must be reprocessed separately. Further, as in Patent Document 1, when crude oil is used, the recovery rate is lower than that of kerosene, and when the recovered liquid that has absorbed the hydrocarbon compound is returned to the crude oil tank, the absorbed light hydrocarbons There has been a concern that the proportion of light fractions such as compounds and inorganic gases will increase, and light gases such as hydrocarbon gas and inorganic gas re-evaporated from the breather valve of the crude oil tank will be discharged.

  Therefore, there is a need for a recovery system that can reduce the amount of air pollutants released into the atmosphere and easily recover hydrocarbon compounds contained in exhaust gas discharged from the transport tank at a high recovery rate. .

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a hydrocarbon recovery system that improves the recovery rate of hydrocarbon compounds, a degassing device used therefor, and a hydrocarbon recovery method. To do.

  In order to achieve the above object, the present invention provides a hydrocarbon recovery system for recovering a hydrocarbon compound contained in an exhaust gas from a transport tank, wherein a compressed product containing a hydrocarbon compound by pressurizing the exhaust gas is provided. A compressor for discharging, an absorption device that absorbs at least a part of the hydrocarbon compound in the absorbing hydrocarbon oil by contacting the compressed material with the absorbing hydrocarbon oil in a pressurized state, and an absorption device; There is provided a hydrocarbon recovery system comprising a degassing device for reducing the pressure of the liquid and separating it into a separation gas containing a light fraction and a recovery liquid containing at least part of an absorbing hydrocarbon oil and a hydrocarbon compound.

  In such a hydrocarbon recovery system, the exhaust gas is pressurized by a compressor, and the resulting compressed product is brought into contact with the absorbing hydrocarbon oil in a pressurized state, so that the hydrocarbon compound contained in the exhaust gas is absorbed. Absorption into hydrocarbon oil can be promoted. For this reason, the hydrocarbon compound can be recovered at a sufficiently high recovery rate. Further, in the deaeration device, by reducing the pressure of the absorption liquid that has absorbed the hydrocarbon compound, the separation gas containing the light fraction and the recovery liquid containing at least a part of the hydrocarbon oil for absorption and the hydrocarbon compound are obtained. Since it is separated, the light fraction contained in the recovered liquid can be sufficiently reduced. Thereby, re-evaporation of the light fraction from the recovered liquid can be sufficiently suppressed. Further, since the recovered liquid can be used again as the absorbing hydrocarbon oil, the hydrocarbon compound can be easily recovered.

  Further, in the present invention, a hydrocarbon recovery system for recovering a hydrocarbon compound contained in an exhaust gas from a transport tank provided in a crude oil tanker, the compressed product containing the hydrocarbon compound by pressurizing the exhaust gas A compressor that discharges the compressed material, and an absorbent device that absorbs at least a part of the hydrocarbon compound into the absorbent crude oil by bringing the compressed product into contact with the absorbent crude oil under pressure. Thus, a hydrocarbon recovery system is provided that includes a separation gas containing a light fraction and a degassing device that separates the recovered crude oil and at least a part of the hydrocarbon compound into a recovered liquid.

  In such a hydrocarbon recovery system, the exhaust gas from the transport tank provided in the crude oil tanker is pressurized by a compressor, and the resulting compressed product is brought into contact with the crude oil for absorption in a pressurized state. The absorption of the hydrocarbon compound contained in the gas into the absorbing crude oil can be promoted. For this reason, the hydrocarbon compound can be recovered at a sufficiently high recovery rate. Further, in the deaeration device, the absorption liquid that has absorbed the hydrocarbon compound is depressurized to be separated into a separation gas containing a light fraction and a recovery liquid containing at least a part of the crude oil for absorption and the hydrocarbon compound. Therefore, the light fraction in the recovered liquid can be sufficiently reduced. Thereby, re-evaporation of the light fraction from the recovered liquid can be sufficiently suppressed. Further, since the recovered liquid can be used again as the crude oil for absorption, the hydrocarbon compound can be easily recovered. Furthermore, since crude oil is used as a liquid for absorbing hydrocarbon compounds, it is particularly useful in crude oil storage bases and crude oil relay bases where refined petroleum products or semi-finished products cannot be easily arranged.

  Moreover, it is preferable that the hydrocarbon recovery system of the present invention further includes a cooler for cooling the compressed product between the compressor and the absorber.

  By providing such a cooler, the compressed product can be cooled and more hydrocarbon compounds can be liquefied. As a result, more hydrocarbon compound is absorbed by the liquefied hydrocarbon, and the recovery rate of the hydrocarbon compound can be further improved. In addition, the amount of release of hydrocarbon compounds and their combustion gases into the atmosphere can be more sufficiently reduced.

  In the present invention, it is also used in a hydrocarbon recovery system for recovering a hydrocarbon compound contained in an exhaust gas from a transport tank, and depressurizing an absorbing liquid obtained by absorbing a compressed product of the exhaust gas in an absorbing hydrocarbon oil. The degassing device for separating the separation gas containing the light fraction and the recovery liquid containing at least a part of the absorbing hydrocarbon oil and hydrocarbon compound, wherein the absorption liquid is supplied, and the separation gas and the recovery liquid For a hydrocarbon recovery system including a tray for separating the recovered liquid separated from the absorption liquid and a down pipe for transferring the recovered liquid staying in the tray downward. A degassing device is provided.

  Such a deaerator separates light fractions such as hydrocarbon compounds and inorganic gases from the absorbent as a separation gas by reducing the pressure of the absorbent, so that the light fraction is sufficiently reduced. A liquid can be obtained. As a result, re-evaporation of the light fraction from the recovered liquid can be sufficiently suppressed, and the hydrocarbon compound can be recovered with a sufficiently high recovery rate. Further, since the recovered liquid can be used again as the absorbing hydrocarbon oil, the hydrocarbon compound can be easily recovered. Furthermore, since the recovery liquid is transferred downward in the container body by the tray and the down pipe, this deaeration device can suppress the generation of static electricity in the container body and is excellent in safety. .

  The present invention is also a hydrocarbon recovery method for recovering a hydrocarbon compound contained in an exhaust gas from a transport tank, wherein the compression step discharges a compressed product containing the hydrocarbon compound by pressurizing the exhaust gas; By bringing the compressed product into contact with the absorbing hydrocarbon oil under pressure, an absorbing step of absorbing at least a part of the hydrocarbon compound into the absorbing hydrocarbon oil to obtain an absorbing liquid, and reducing the absorbing liquid, There is provided a hydrocarbon recovery method comprising a separation gas containing a light fraction and a degassing step of separating into a recovery liquid containing at least a part of an absorbing hydrocarbon oil and a hydrocarbon compound.

  In such a hydrocarbon recovery method, since the compressed product obtained by pressurizing the exhaust gas with a compressor is brought into contact with the absorbing hydrocarbon oil in a pressurized state, it is used for absorbing hydrocarbon compounds contained in the exhaust gas. Absorption into hydrocarbon oil can be promoted. For this reason, the hydrocarbon compound can be recovered at a sufficiently high recovery rate. In the degassing step, the absorption liquid that has absorbed the hydrocarbon compound is depressurized, whereby a separation gas containing a light fraction and a recovery liquid containing at least a part of the hydrocarbon oil for absorption and the hydrocarbon compound are obtained. Since it is separated, the light fraction contained in the recovered liquid can be sufficiently reduced. Thereby, re-evaporation of the light fraction from the recovered liquid can be sufficiently suppressed. Moreover, since the recovered liquid can be used again as the absorbing hydrocarbon oil in the absorption step, the hydrocarbon compound can be easily recovered.

  According to the present invention, a hydrocarbon recovery system that can easily recover a hydrocarbon compound, has a sufficiently high recovery rate, and can sufficiently reduce the release amount of the hydrocarbon compound, its combustion gas, and air pollutants into the atmosphere. , And a deaeration device used therefor, and a hydrocarbon recovery method can be provided.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

  FIG. 1 is a schematic configuration diagram showing a preferred embodiment of the hydrocarbon recovery system of the present invention. The hydrocarbon recovery system 100 according to the present embodiment recovers hydrocarbon compounds contained in the exhaust gas from the transport tank 10, and includes a compressor 12, an absorption tower 14, a degassing tower 16, a recovery tank 18, A combustion device 20 and a boiler 22 are provided.

  The transport tank 10 is installed in a tanker, a tank lorry, a tank car, etc. that transports crude oil, various petroleum products, and semi-finished products. Examples of various petroleum products include LPG, gasoline, kerosene, light oil, heavy oil, naphtha, chemicals such as xylene and benzene, and examples of semi-finished products include blend bases of these products.

  After unloading the above-mentioned crude oil, various petroleum products, and semi-finished products, an inorganic gas such as nitrogen is introduced into the transport tank 10 for ensuring safety. For example, safety is ensured by adjusting the oxygen concentration to 6% by volume or less. As the inorganic gas, nitrogen, carbon dioxide, boiler exhaust gas containing a low concentration of oxygen, or the like can be used.

  The inside of the transport tank 10 in which such an inorganic gas is sealed contains a hydrocarbon gas derived from the transported crude oil, various petroleum products, and semi-finished products, and an inorganic gas such as nitrogen, carbon dioxide, and oxygen. Is satisfied by. Examples of the hydrocarbon gas include volatile hydrocarbon gas, for example, gas having 1 to 7 carbon atoms, more specifically, methane, ethane, ethylene, propane, propylene, butane, butene, pentane, hexane and the like. Can do. In addition, the temperature of the tank 10 for conveyance can be made into normal temperature, and a pressure can be made equivalent to atmospheric pressure.

  As the compressor 12, a normal gas compressor can be used. The compressor 12 is connected to the transport tank 10 by a pipe L10. As the pipe L10, a loading arm that connects the tanker and the compressor, a normal pipe, and a combination thereof can be used.

  The compressor 12 sucks the exhaust gas in the transport tank 10 and discharges the compressed product pressurized to a predetermined pressure P1. As pressure P1, 100-1000 kPaG is preferable and 200-500 kPaG is more preferable. When the pressure P1 is less than 100 kPaG, there is a tendency that a sufficient recovery rate of the hydrocarbon compound is not obtained, and when it exceeds 1000 kPaG, from the viewpoint of securing pressure resistance, the construction cost of the hydrocarbon recovery facility tends to increase. . Moreover, the temperature of a compression thing can be 0-50 degreeC. The compressed product can contain a hydrocarbon compound and an inorganic gas contained in the exhaust gas. The compressed product is a gas, a liquid, or a mixture thereof. The compressor 12 is connected to the absorption tower 14 by a pipe L12. As the pipe L12, a normal pipe can be used.

  The absorption tower 14 makes the gas-liquid contact between the compressed material introduced from the compressor 12 via the pipe L12 and the absorbing hydrocarbon oil introduced from the recovery tank 18 via the pipe L18. Thereby, the absorption tower 14 absorbs at least a part of the hydrocarbon compound contained in the compressed product in the absorbing hydrocarbon oil, and the unabsorbed product in which at least a part of the hydrocarbon compound is removed from the compressed product. Exhaust gas. In addition, normal piping can be used as the piping L18.

  The contact method between the compressed product and the absorbing hydrocarbon oil is preferably countercurrent contact from the viewpoint of improving the amount of the hydrocarbon compound absorbed by the absorbing hydrocarbon oil. Normally, the compressed product contains an inorganic gas, and most of the inorganic gas is discharged as an unabsorbed gas, but some of the inorganic gas may be contained in the absorbing liquid at a saturated concentration.

  As the hydrocarbon oil for absorption, various hydrocarbon oils that absorb hydrocarbon compounds, such as crude oil, various petroleum products, semi-finished products, and the like can be used. In this embodiment, crude oil is used. Crude oil can be preferably used because it is easily obtained and procured and has excellent energy efficiency. In other words, it is difficult to arrange petroleum products and semi-finished products at crude oil export bases, stockpiling bases, relay bases, etc., but crude oil can be easily arranged. In addition, the absorbing hydrocarbon oil needs to be refined in order to produce a product or a semi-finished product after absorbing the hydrocarbon compound, but if a refined petroleum product or semi-finished product is used as the absorbing hydrocarbon oil, This is not preferable in terms of energy efficiency because a purification process is required again. In this embodiment, since crude oil is used as the hydrocarbon oil for absorption and the redundant refining process is avoided, the energy efficiency is excellent.

  The absorption tower 14 contains a packing 14a therein. Examples of the filler 14a include glass, ceramic, or stainless steel Raschig rings. Glass or ceramic Raschig rings are excellent in corrosion resistance, and stainless steel Raschig rings are hard to break and excellent in mechanical strength. By accommodating such a packing 14a in the absorption tower 14, the contact between the compressed product and the absorbing hydrocarbon oil can be efficiently performed, and hydrocarbon compounds discharged as unabsorbed gas can be reduced. it can.

  The contact time between the absorbing hydrocarbon oil and the compressed product in the absorption tower 14 is preferably 10 seconds to 10 minutes. If the contact time is less than 10 seconds, the amount of hydrocarbon compound absorbed by the absorbing hydrocarbon oil tends to decrease. On the other hand, if the contact time exceeds 10 minutes, the construction cost of the absorption tower 14 tends to increase.

The gas-liquid ratio (volume of absorbing hydrocarbon oil at 15 ° C./volume of compressed product in standard state (0 ° C., 1 atm)) is preferably 10 to 200 L / Nm ³ , and 12 to 180 L / Nm. ³ is more preferable, and 15 to 150 L / Nm ³ is particularly preferable. When the gas-liquid ratio is less than 10 L / Nm ³ , the amount of hydrocarbon compound absorbed by the absorbing hydrocarbon oil tends to decrease. On the other hand, when the gas-liquid ratio exceeds 200 L / Nm ³ , the construction cost of the absorption tower 14 tends to increase.

  The temperature in the absorption tower 14 is preferably 40 ° C. or lower, more preferably 38 ° C. or lower, and particularly preferably 35 ° C. or lower. When the temperature in the absorption tower 14 exceeds 40 ° C., the evaporation amount of the absorbing hydrocarbon oil tends to increase and the absorption amount tends to decrease.

  The pressure P2 in the absorption tower 14 is preferably equal to the pressure P1 of the compressed product. Specifically, the pressure P2 is preferably 100 to 1000 kPaG, and more preferably 200 to 500 kPaG. When the pressure P2 in the absorption tower 14 is less than 100 kPaG, the amount of the hydrocarbon compound absorbed by the absorbing hydrocarbon oil tends to decrease, and when it exceeds 1000 kPaG, from the viewpoint of securing pressure resistance, Construction costs tend to increase.

  The lower part of the absorption tower 14 is connected to the deaeration tower 16 by a pipe L15. Further, the upper part of the absorption tower 14 is connected to the combustion device 20 by a pipe L14. Ordinary pipes can be used as the pipes L14 and L15.

  The absorbing liquid discharged by the pipe L15 connected to the lower portion of the absorption tower 14 may contain a small amount of inorganic gas in addition to the absorbing hydrocarbon oil and the hydrocarbon compound. The unabsorbed gas discharged by the pipe L14 connected to the upper portion of the absorption tower 14 may contain a light hydrocarbon compound such as methane or ethane in addition to the inorganic gas.

  As the combustion apparatus 20, a normal combustion apparatus for fuel gas processing can be used. Thereby, the unabsorbed gas containing the hydrocarbon compound transferred from the absorption tower 14 via the pipe L14 can be burned and safely released into the atmosphere. In the present embodiment, the combustion apparatus 20 is used as a processing apparatus for unabsorbed gas. However, the unabsorbed gas can be processed by other methods. For example, it can be used as a fuel for a heating furnace of a boiler or other apparatus.

  The deaeration tower 16 is connected to the absorber 14 by a pipe L15. The absorption liquid discharged from the lower part of the absorption device 14 is introduced from the introduction part 16a of the deaeration tower 16 via the pipe L15.

  FIG. 2 is a schematic cross-sectional view showing a preferred embodiment of the deaeration tower of the present invention. The deaeration tower 16 includes a tray 40 at the upper part of the main body of the deaeration tower 16 and a down pipe 42 extending from the tray 40 downward in the main body of the deaeration tower 16.

  The pressure P3 in the deaeration tower 16 is lower than the pressure P2 in the absorption tower. For this reason, when the absorbing liquid is introduced into the degassing tower 16 from the introducing portion 16a, it is possible to separate light fractions such as light hydrocarbon compounds and inorganic gas contained in the absorbing liquid as the pressure decreases. That is, the absorption liquid can be separated into a separation gas containing a light fraction and a recovery liquid by the deaeration tower 16.

  The tray 40 of the deaeration tower 16 once retains the recovered liquid obtained by separating light hydrocarbon compounds and inorganic gas from the absorbing liquid. As a result, the content of light hydrocarbons and inorganic gas remaining in the recovered liquid can be further reduced. Further, once the collected liquid is retained in the tray 40, the retained collected liquid can be transferred downward in the main body of the deaeration tower 16 by the down pipe 42.

  The recovered liquid transferred downward by the down pipe 42 is preferably temporarily retained in the lower part of the deaeration tower 16. As a result, the opening at the lower end of the down pipe 42 can be disposed in the collected liquid (below the collected liquid level 46) stored in the lower part of the deaeration tower 16, and the occurrence of splashes due to the fall of the collected liquid, etc. Generation of static electricity can be prevented. Note that the retention amount of the recovered liquid in the lower portion of the deaeration tower 16 can be adjusted by ordinary level control.

  A pressure regulating valve 44 is provided in the pipe L16 connected to the top of the deaeration tower 16. The pressure adjusting valve 44 can adjust the pressure P3 in the deaeration tower 16. The pressure P3 in the deaeration tower 16 is preferably −500 to 500 kPaG, and more preferably 0 to 300 kPaG. When the pressure P3 in the deaeration tower 16 is less than 0 kPaG, the concentration of the hydrocarbon compound in the separation gas tends to increase. On the other hand, when the pressure P3 of the deaeration tower 16 exceeds 500 kPaG, the concentration of the light hydrocarbon compound in the recovered liquid tends to increase, and the pressure of the recovery tank 18 tends to increase. Note that the recovery rate of the hydrocarbon compound and the concentration of the hydrocarbon gas in the separation gas can be arbitrarily adjusted by changing the pressure P3 in the deaeration tower 16.

  The pipe L16 connected to the discharge part 16b at the top of the deaeration tower 16 branches into a pipe L20 and a pipe L22, and is connected to the combustion device 20 and the boiler 22 respectively (FIG. 1). As a result, a separation gas containing a light fraction such as a light hydrocarbon compound or an inorganic gas can be treated. The separated gas sent to the combustion device 20 is burned and discharged into the atmosphere, and the separated gas sent to the boiler 22 is used as fuel for the boiler 22. In the present embodiment, the combustion apparatus 20 and the boiler 22 are used as the separation gas processing apparatus, but the separation gas may be processed by other methods. For example, it can be used as a fuel for a heating furnace of another apparatus.

  On the other hand, the pipe L17 connected to the discharge part 16c at the bottom of the deaeration tower 16 is connected to the recovery tank 18. Normal piping can be used as the piping L16 and L17. As the recovery tank 18, a normal crude oil tank installed on the ground can be used. As a tank other than the crude oil tank, a tank dedicated to the recovery system, a petroleum product tank, or a semi-finished product tank can be used. The recovered liquid stored in the lower part of the deaeration tower 16 can be sent to the recovery tank 18 by a pump or the like via the pipe L17. In the present embodiment, the tank of the absorbing hydrocarbon oil source and the tank of the recovery liquid discharge destination are the same tank (recovery tank 18), but these tanks may be used separately.

  When a tank storing Middle East crude oil is used as the recovery tank 18, the internal pressure of the recovery tank 18 is usually 40 to 80 kPaG due to the vapor pressure of the crude oil. When a large amount of a light hydrocarbon compound having a high vapor pressure is mixed in the recovery tank 18, the internal pressure of the recovery tank 18 rises, and hydrocarbon gas may be discharged out of the recovery tank 18 by the breather valve. However, according to the hydrocarbon recovery system of the present embodiment, the content of light hydrocarbon compounds in the recovery liquid is sufficiently reduced, so that the internal pressure of the recovery tank 18 after the recovery liquid is introduced is increased. Can be prevented. Further, such a recovered liquid has a sufficiently reduced content of inorganic gas. Therefore, it is possible to sufficiently suppress the decrease in the absorption performance of the absorbing hydrocarbon oil sent from the recovery tank 18 to the absorption tower 14.

  Note that the hydrocarbon recovery method using the hydrocarbon recovery system according to the above embodiment compresses exhaust gas from the transportation tank 10 installed in a crude oil tanker or the like to discharge a compressed product containing a hydrocarbon compound. A step of absorbing the compressed product with the absorbing hydrocarbon oil under pressure to absorb at least a portion of the hydrocarbon compound in the absorbing hydrocarbon oil to obtain an absorbing liquid; and the reducing of the absorbing liquid And a degassing step of separating into a separation gas containing a light fraction and a recovery liquid containing at least a part of the hydrocarbon oil for absorption and the hydrocarbon compound.

  In the compression process, the exhaust gas from the transport tank 10 is pressurized to a predetermined pressure P1 to obtain a compressed product, and in the absorption process, hydrocarbon compounds are easily absorbed from the compressed product in the pressurized state. It can be absorbed in hydrogen oil. Therefore, the hydrocarbon compound can be recovered in the recovery liquid with a sufficiently high recovery rate. For example, the recovery rate can be increased by 10 to 30% (standard condition conversion) as compared with a recovery method using a hydrocarbon recovery system without a compressor. The recovery rate can be calculated as the ratio of the hydrocarbon compound recovered in the recovery liquid to the entire hydrocarbon compound contained in the exhaust gas.

  In the degassing step, the absorbing liquid in a pressurized state is reduced to a predetermined pressure P3, so that the absorbing liquid is separated into a separation gas containing a light fraction such as a light hydrocarbon compound and an inorganic gas, and the light fraction. It can be separated into a recovered liquid with a reduced content. Since this recovered liquid has a sufficiently reduced content of light hydrocarbon compound and inorganic gas, it is possible to sufficiently reduce re-evaporation of the light hydrocarbon compound in the recovery tank 18 at the discharge destination. . Further, this recovered liquid can be introduced into the absorption tower 14 as an absorbing hydrocarbon oil having sufficient absorption efficiency in the absorption step. Thus, since the hydrocarbon oil for absorption of the absorption tower 14 can be continuously introduced, the hydrocarbon compound in the exhaust gas can be easily recovered.

  The recovered liquid in the present embodiment contains the absorbing hydrocarbon oil used in the absorption step and at least a part of the hydrocarbon compound contained in the exhaust gas from the transport tank. Therefore, the amount of the recovered hydrocarbon compound can be measured by subtracting the amount of the absorbing hydrocarbon oil used in the absorption step from the amount of the recovered liquid obtained in the deaeration step.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, a cooler may be provided between the compressor 12 and the absorption tower 14. Since the pressurized compressed product is cooled by the cooler, the absorption amount of the hydrocarbon compound by the absorbing hydrocarbon oil in the absorption tower 14 can be further improved. In addition, a normal heat exchanger can be used as a cooler. Water or ammonia can be used as the cooling medium. In addition, when providing a cooler, it is preferable that the temperature of the compressed material in the exit of a cooler shall be 0-20 degreeC.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example at all.

Example 1
The hydrocarbon compound was recovered by the hydrocarbon recovery system 100 shown in FIG. Specifically, a hydrocarbon compound was recovered from a tank of a crude oil tanker sealed with boiler exhaust gas (mixed gas of nitrogen, carbon dioxide, and oxygen). In addition, the component analysis of each gas in a present Example was performed by the gas chromatography.

  First, a crude oil tanker tank 10 was connected with a crude oil supply loading arm and an exhaust gas exhaust loading arm. Next, loading of the crude oil into the crude oil tanker tank 10 was started, and at the same time, compression of the exhaust gas discharged from the crude oil tanker tank by the gas compressor 12 was started. The pressure of the compressed gas at the outlet of the gas compressor 12 was 348 kPaG. The gas flow rate of the compressed gas was measured, and the component gas was analyzed by sampling the compressed gas at the outlet of the gas compressor 12.

  Next, crude oil (Arabian light crude oil) stored in the recovery tank 18 was introduced into the absorption tower 14 for absorption of hydrocarbon compounds. The crude oil and the compressed gas were brought into countercurrent contact with the absorption tower 14 to obtain an absorption liquid in which the hydrocarbon compound was absorbed. The flow rate of the unabsorbed gas discharged from the top of the absorption tower 14 was measured, and the component analysis of the unabsorbed gas was performed.

  Next, the absorbing liquid discharged from the lower part of the absorption tower 14 was introduced into the deaeration tower 16 to perform deaeration. The outlet pressure at the top of the degassing tower 16 was adjusted to 80 kPaG by the pressure regulating valve 44 (FIG. 2). As a result, the absorption liquid was separated into a recovered liquid containing at least a part of the crude oil and the hydrocarbon compound and a separation gas containing the light hydrocarbon compound and the inorganic gas. The gas flow rate of the separation gas discharged from the top of the deaeration tower 16 was measured, and the components of the separation gas were analyzed.

  The component analysis results of the compressed gas, unabsorbed gas, and separated gas are as shown in Table 1. The component of the compressed gas is the same as the component of the exhaust gas from the tank 10. Each gas contains oxygen and nitrogen as components other than those listed in Table 1.

As shown in Table 1, when compared with the hydrocarbon gas flow rate, the hydrocarbon recovery system 100 was able to recover 1554 Nm ³ / h of the hydrocarbon compound. (Recovery rate: 62.9%) Further, the ratio of the component having 1 to 3 carbon atoms is higher in the unabsorbed gas and the separated gas than in the compressed gas. From this data, it was confirmed that a hydrocarbon compound having a high added value and a large number of carbon atoms (4 or more carbon atoms) can be selectively recovered. Further, the internal pressure of the recovery tank 18 was maintained at about 40 to 50 kPaG from the start to the end of recovery of the hydrocarbon compound. A large pressure increase in the recovery tank 18 was not observed.

(Example 2)
The hydrocarbon compound was recovered by the hydrocarbon recovery system 100 in the same manner as in Example 1 except that the outlet pressure at the top of the degassing tower 16 was adjusted to 100 kPaG by the pressure control valve 44. In this case, the gas flow rate of the separation gas discharged from the top of the deaeration tower 16 was reduced by 15.6% from that of Example 1 to 176 Nm ³ / h. Further, the recovery rate of the hydrocarbon compound was 63.3%. Further, the internal pressure of the recovery tank 18 was maintained at about 40 to 50 kPaG from the start to the end of recovery of the hydrocarbon compound. A large pressure increase in the recovery tank 18 was not observed.

It is a schematic block diagram which shows suitable embodiment of the hydrocarbon recovery system of this invention. It is a schematic sectional drawing which shows suitable embodiment of the deaeration tower of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Transport tank (tank), 12 ... Compressor, 14 ... Absorption tower, 14a ... Packing, 16 ... Deaeration tower, 16a ... Introduction part, 16b, 16c ... Discharge part, 18 ... Recovery tank, 20 ... Combustion Equipment: 22 ... Boiler, 40 ... Tray, 42 ... Down pipe, 44 ... Pressure regulating valve, 46 ... Recovery liquid level, L10, L12, L14. L15, L16, L17, L18, L20, L22 ... piping, 100 ... hydrocarbon recovery system.

Claims (8)

A hydrocarbon recovery system for recovering hydrocarbon compounds contained in exhaust gas from a transport tank,
A compressor for pressurizing the exhaust gas and discharging a compressed product containing the hydrocarbon compound;
An absorber that obtains an absorbent by allowing the absorbent hydrocarbon oil to absorb at least a part of the hydrocarbon compound by bringing the compressed product into contact with the absorbent hydrocarbon oil in a pressurized state;
A degassing device that depressurizes the absorption liquid and separates it into a separation gas containing a light fraction and a recovery liquid containing at least a part of the hydrocarbon oil for absorption and the hydrocarbon compound;
The deaerator includes a container body that is supplied with the absorbing liquid and separates into the separation gas and the recovered liquid, and the recovered liquid separated from the absorbing liquid is retained in the container body. And a down pipe for transferring the recovered liquid staying in the tray downward . A hydrocarbon recovery system for recovering hydrocarbon compounds contained in exhaust gas from a transport tank provided in a crude oil tanker,
A compressor for pressurizing the exhaust gas and discharging a compressed product containing the hydrocarbon compound;
An absorber that obtains an absorbing liquid by allowing at least a part of the hydrocarbon compound to be absorbed in the absorbing crude oil by contacting the compressed product with the absorbing crude oil in a pressurized state;
A degassing device that depressurizes the absorption liquid and separates it into a separation gas containing a light fraction and a recovery liquid containing at least a part of the crude oil for absorption and the hydrocarbon compound;
The deaerator includes a container body that is supplied with the absorbing liquid and separates into the separation gas and the recovered liquid, and the recovered liquid separated from the absorbing liquid is retained in the container body. hydrocarbon recovery system that Yusuke the tray to, and a down pipe for transferring the recovered liquid staying in the tray downwards.   The hydrocarbon recovery system according to claim 1, further comprising a cooler that cools the compressed product between the compressor and the absorber. The said deaeration apparatus is a hydrocarbon recovery system as described in any one of Claims 1-3 further equipped with the pressure control valve which adjusts the pressure inside the said container main body. By using a hydrocarbon recovery system that recovers hydrocarbon compounds contained in the exhaust gas from the transport tank and reducing the absorption liquid obtained by absorbing the compressed product of the exhaust gas into the absorbent hydrocarbon oil, A degassing device that separates the separated gas into a separated liquid and the recovered liquid containing at least part of the hydrocarbon oil for absorption and the hydrocarbon compound,
A container body that is supplied with the absorption liquid and separates into the separation gas and the recovered liquid;
Inside the container body,
A tray for retaining the recovered liquid separated from the absorbing liquid;
A down pipe for transferring the recovered liquid staying in the tray downward;
A degassing device for a hydrocarbon recovery system. The deaeration device for a hydrocarbon recovery system according to claim 5, further comprising a pressure adjustment valve that adjusts a pressure inside the container body. A hydrocarbon recovery method for recovering a hydrocarbon compound contained in an exhaust gas from a transport tank,
A compression step of pressurizing the exhaust gas to discharge a compressed product containing the hydrocarbon compound;
An absorption step of bringing the compressed product into contact with an absorbing hydrocarbon oil under pressure to absorb at least a part of the hydrocarbon compound into the absorbing hydrocarbon oil to obtain an absorbing liquid;
A degassing step of depressurizing the absorption liquid and separating it into a separation gas containing a light fraction and a recovery liquid containing at least a part of the hydrocarbon oil for absorption and the hydrocarbon compound;
With
In the degassing step, the absorbing liquid is supplied to a container main body of a degassing device, the separation gas and the recovered liquid are separated in the container main body, and the tray provided inside the container main body has the A hydrocarbon recovery method in which the recovered liquid separated from the absorbing liquid is temporarily retained, and the retained recovered liquid is transferred downward by a down pipe . The hydrocarbon recovery method according to claim 7, wherein in the degassing step, the pressure inside the container body is adjusted by a pressure regulating valve.

Images