JP6421633B2 - Cooling method for heavy oil - Google Patents

Description

  The present invention relates to a method for cooling heavy oil and a heat exchanger for heavy oil. More specifically, the present invention relates to a cooling method and a heat exchanger that can rapidly cool heavy oil such as coal tar, coal tar pitch, or petroleum pitch in a high temperature state.

When coke is produced by dry distillation of coal in a coke oven, coal tar and coal tar pitches that are a coal tar derivative (including soft pitch, medium pitch, hard pitch, and pitch during various work processes) are included. ) Are produced as by-products, but these are used as raw materials for various purposes.
Coal tar or the like is a mixture, but when these are used as raw materials, the desired component ratio varies depending on the purpose and application. For example, when used as a raw material for impregnation pitch, needle coke, carbon fiber, etc., a quinoline insoluble component ratio (hereinafter sometimes abbreviated as QI (Quinoline Insoluble)), which is a guideline for the content of the polymer resinous substance. Is required. On the other hand, when used as a raw material for a special carbon material or a binder pitch, a material having a high QI is required.

The component ratio of coal tar and the like generated from the coke oven varies depending on the structure and method of the coke oven, the quality of coal as a raw material, the dry distillation conditions, and the like. In the dry distillation process of coke production, the component ratio also changes over time.
For this reason, when using coal tar or the like as a raw material for various applications, it is important in product management and process management to accurately measure the characteristics such as the component ratio and properties represented by QI.

Conventionally, the measurement of solvent-insoluble components of coal tar or coal tar pitch has been performed manually, but in recent years, in-line and on-line operations are being promoted for continuous, quick, and simple measurement. Various measurement methods have been proposed.
For example, a method using a fine particle counter (particle counter) for measuring QI of coal tar pitches (Patent Document 1), and a method using an integrating sphere turbidimeter for measuring the concentration of solvent insoluble components such as coal tar. (Patent Document 2), a method of measuring the concentration of solvent insoluble components such as coal tar based on the absorbance of a specific wavelength of visible, near infrared, or infrared light (Patent Document 3) is disclosed.

JP-A-4-9664 JP 2012-251998 A JP 2014-178312 A

Normally, coal tar pitch obtained by distilling coal tar by-produced from a coke oven is produced at about 200 to 340 ° C. Such solvent insoluble components of heavy oil are treated as in Patent Documents 1 to 3. When measuring by this method, it cools to the temperature of about 60-140 degreeC, and is performed. Therefore, it is necessary to cool the heavy oil with a temperature difference of 100 ° C. or more.
Heavy oils such as coal tar and coal tar pitch are generally highly viscous fluids and contain a large amount of solids (suspension components). Therefore, when measuring the solvent insoluble content of the cooled heavy oil, it is necessary to accurately mix with the solvent at a high dilution ratio of usually about 100 to 3000 times.

For this reason, one of the objectives of making measurement inline and online is to speed up the process. However, if a long time is required for the cooling process of the heavy oil to be measured, Is difficult to achieve.
Generally, when cooling a fluid, it is often done by flowing both the fluid and the refrigerant through a heat conductor such as a cooling pipe to exchange heat, but according to the study by the present inventors, Even when this method is used for heavy oil such as coal tar and coal tar pitch, it has been found that rapid cooling to the extent that in-line measurement is possible is difficult. Furthermore, it has been found that when a tubular heat conductor is used as a cooling pipe, the temperature of the heavy oil after cooling may become uneven. Furthermore, it has been found that if the cooling pipe is lengthened for rapid cooling, troubles such as the need for a power source such as a pump for transferring heavy oil occur.

However, as the prior art exemplified in Patent Documents 1 to 3, although there are disclosures about in-line measurement methods to which various measuring devices are applied, in any document, the temperature of heavy oil used for in-line measurement is not specified. No information is disclosed as to whether it can be cooled quickly and stably.
In view of the above circumstances, the present invention provides a method and apparatus capable of rapidly and stably cooling the temperature of heavy oil such as coal tar, coal tar pitch or petroleum-based pitch, while being a simple method. The task is to do.

As a result of intensive studies to solve the above problems, the present inventors have aimed to cool heavy oil that flows continuously in-line, that is, in the piping, but the cooling process is performed by blocking the flow. As a result, the inventors have found that this can be solved, and have completed the present invention.
That is, the gist of the present invention resides in the following [1] to [11].
[1] A method of cooling heavy oil flowing in a pipe using a heat exchanger, wherein the heavy oil is cooled without flowing, and after the heavy oil is cooled, the heavy oil The heavy oil is cooled from the heat exchanger.
[2] The method for cooling heavy oil according to [1], wherein the heat exchanger includes a heat transfer tube having a ratio (L / D) of a tube length L to a tube diameter D of 5 or more.
[3] The method for cooling heavy oil according to [2], wherein heat exchange is performed in a state where heavy oil is present inside the heat transfer tube and refrigerant is present outside the heat transfer tube.
[4] The heavy oil cooling method according to any one of [1] to [3], wherein the viscosity of the heavy oil is 15 to 15000 mPa · s at 100 ° C.
[5] The method for cooling heavy oil according to any one of [1] to [4], wherein the temperature difference between the heavy oil before cooling and after cooling is 40 to 300 ° C.
[6] The heavy oil cooling method according to any one of [1] to [5], wherein the shut-off is performed by a shut-off valve.
[7] The heavy oil cooling method according to any one of [1] to [6], wherein the discharging is performed by press-fitting heavy oil or gas.
[8] The method for cooling heavy oil according to any one of [1] to [7], wherein the heavy oil is at least one selected from coal tar, coal tar pitch, or petroleum-based pitch.
[9] The heavy oil cooling method according to any one of [1] to [8], wherein the refrigerant contains any one selected from vegetable oil, animal oil, mineral oil, chemically synthesized oil, air, water, and steam. .
[10] A heat exchanger that cools heavy oil using a heat transfer tube having a ratio (L / D) of the tube length L to the tube diameter D of 5 or more, and the heavy oil is filled in the heat transfer tube A heavy oil heat exchanger having a mechanism for shutting off and cooling the flow of the heavy oil in a heated state, and discharging the heavy oil after being cooled.
[11] A solvent is mixed with the heavy oil cooled by the method according to any one of [1] to [9], and an insoluble content in a mixed solution of the heavy oil and the solvent is measured. Method for measuring the content of min.

  According to the present invention, it is possible to provide a method and apparatus capable of rapidly and stably cooling the temperature of heavy oil such as coal tar, coal tar pitch, or petroleum pitch, while being a simple method. it can.

The schematic diagram which shows an example of the heat exchanger used for the cooling method of the heavy oil of this invention. The figure which shows the temperature change of the heavy oil in Example 1. FIG. The figure which shows the cooling temperature of the heavy oil in the reference example 1. FIG. The figure which shows the cooling temperature of the heavy oil in the reference example 1. FIG. The figure which shows the cooling temperature of the heavy oil in the reference example 2. FIG. The figure which shows the cooling temperature of the heavy oil in the reference example 2. FIG.

Hereinafter, the present invention will be described in more detail with reference to the embodiments. However, the present invention is not limited to these embodiments as long as the gist thereof is not exceeded.
The present invention relates to a method for cooling heavy oil and a heat exchanger for heavy oil. More specifically, the present invention relates to a cooling method and a heat exchanger capable of rapidly cooling heavy oil such as coal tar, coal tar pitch or petroleum pitch in a high temperature state.
In the present invention, “heat exchanger” and “cooler” are synonymous. In the present invention, “refrigerant” means a heat medium used for cooling.

[1. Heavy oil]
The heavy oil in the present invention is not limited as long as it is generally called heavy oil (heavy oil), but specifically, coal tar and coal tar pitches which are coal tar derivatives (soft pitch, medium pitch, hard oil) Including pitches obtained from various processes such as pitch) and petroleum pitches generated from the petroleum refining process. Further, it may be a mixture of a plurality of coal tars, a mixture of a plurality of coal tar pitches, or a mixture of a plurality of petroleum pitches. Further, it may be a mixture of two or more selected from coal tar, coal tar pitches and petroleum pitches.

  Preferably, the coal tar is coal tar obtained by gradually cooling a coke oven gas generated in a coke oven for crude steel and condensing a high boiling point one. The coal tar pitches are obtained by removing light aromatic components by distillation of coal tar, preferably coal tar obtained from the above-mentioned coke oven.

  The petroleum-based pitches generated from the petroleum refining process are preferably atmospheric distillation residual oil or vacuum distillation residual oil in the petroleum refining process, including residual oil obtained by treating these residual oils with a fluid catalytic cracking apparatus. It is. In addition to aromatic components, these pitches and the like may contain alkyl compounds, heterocyclic compounds, compounds containing elements such as sulfur, nitrogen and oxygen, and simple substances.

The viscosity of the heavy oil targeted in the present invention is not limited, but the viscosity at 100 ° C. (value measured with a B-type viscometer) is usually 15 mPa · s or more, preferably 50 mPa · s or more, more preferably 100 mPa · s. s or more, more preferably 500 mPa · s or more, particularly preferably 1000 mPa · s or more, and usually 15000 mPa · s or less, preferably 13000 mPa · s or less, more preferably 10000 mPa · s or less.
When the viscosity of the heavy oil is less than the lower limit, the possibility of turbulent flow at the time of transfer increases, and thus the effect of the present invention tends to be difficult to exert. When the viscosity of the heavy oil exceeds the upper limit, the viscosity tends to be too high to be transferred, and the cooling effect by the method of the present invention may be reduced.

When coal tar is used as the heavy oil, for the same reason as described above, the viscosity at 40 ° C. (value measured with a B-type viscometer) is usually 100 mPa · s or more, preferably 200 mPa · s or more, more preferably It is 500 mPa · s or more, usually 1500 mPa · s or less, preferably 1200 mPa · s or less, more preferably 1000 mPa · s or less.
When coal tar pitch or petroleum pitch is used as the heavy oil, its viscosity at 100 ° C. (value measured with a B-type viscometer) is usually 100 mPa · s or more, preferably 500 mPa for the same reason as above. S or more, more preferably 1000 mPa · s or more, usually 15000 mPa · s or less, preferably 13000 mPa · s or less, more preferably 10000 mPa · s or less.
The present invention is particularly effective in the case of coal tar pitches or petroleum pitches as compared with coal tar because the effect is remarkably exhibited particularly in heavy oil with high viscosity.

[2. Heavy oil cooling method]
Below, the cooling method of this invention is demonstrated. In the cooling method of the present invention, when the heavy oil flowing in the pipe is cooled using a heat exchanger, the heavy oil is cooled without flowing, and the heavy oil is cooled and then the heavy oil is cooled. Drain the quality oil from the heat exchanger.

Here, “cooling the heavy oil in a state where the flow is blocked” is sufficient if the flow is substantially stopped in the process of cooling the heavy oil. The timing for starting the cooling of the heavy oil and the timing for stopping the flow of the heavy oil are not necessarily the same. That is, the flow may have already stopped at a point before the process of cooling the heavy oil. Moreover, the timing which complete | finishes cooling of heavy oil and the timing which discharge | emit heavy oil from a heat exchange part do not necessarily need to be simultaneous. In other words, the flow may continue to stop for a predetermined time after the cooling of the heavy oil is completed and discharged. From the viewpoint of cooling efficiency and work efficiency, it is preferable that these timings are close at the same time.
Note that “the flow of heavy oil is substantially stopped” means that no external force is applied, such as the fact that the transfer in the piping is interrupted or the stirring operation is not performed. The self-convection of heavy oil itself accompanying the heat transfer that occurs in it is not included in the “flow”.

Conventionally, when cooling a fluid flowing in a pipe, it has been customary to position a part of the pipe as a heat exchanger (heat transfer pipe) and to exchange heat and cool it by flowing a refrigerant outside the heat transfer pipe. It was. Specifically, a double pipe heat exchanger and the like can be mentioned. When using this method to rapidly cool a fluid, generally (1) increase the temperature difference between the fluid and the refrigerant, (2) increase the heat transfer area for heat exchange, (3) the heat transfer tube For example, a method of slowing the flow rate of the fluid passing through the pipe has been adopted.
However, according to studies by the present inventors, it has been found that the following problems occur when this method is used for cooling heavy oil such as coal tar and coal tar pitch.

When the method (1) is adopted for cooling the heavy oil, the heavy oil is solidified or thickened in the vicinity of the inner wall of the heat transfer tube, and a thermal film is formed by losing fluidity. Became clear. Therefore, it has been found that when the temperature of the refrigerant is lowered, the cooling efficiency may rather deteriorate. Furthermore, since the heavy oil flowing through the central portion of the pipe passes through the heat transfer pipe without being substantially cooled, it has been found that the temperature of the discharged heavy oil varies.
When the method (2) is employed for cooling heavy oil, generally, the diameter of the heat transfer tube is reduced or the tube length is increased. However, it has been found that with this method, the viscosity of the heavy oil becomes extremely high, and transfer and discharge are substantially difficult. In order to solve this problem, it is necessary to use a power source such as a transfer pump. In this case, there is a problem that mixing of heavy oil to be cooled with other heavy oil becomes remarkable. It was. In the first place, there is an appropriate transfer pump that does not cause sludge or other clogging or clogging with heavy oil with a small flow rate (about 0.1 to 10 L / min) that is the target of in-line process analysis. Not done.
When the method (3) is adopted for cooling the heavy oil, the diameter of the heat transfer pipe is increased, or the volume flow rate of the heavy oil piping line itself is decreased. However, since the former method tends to deteriorate the cooling efficiency, it is contrary to the above (2), and the latter method has a problem in that the piping is blocked.

  In response to the above problems, if heavy oil is cooled by heat exchange in a state where the flow is interrupted, the cooling efficiency decreases due to the formation of a thermal boundary film, the cooling temperature of heavy oil varies, and transport Various problems such as power supply and blockage of piping can be solved.

<Cooling method>
In the present invention, heavy oil flowing in the pipe is cooled using a heat exchanger, but the heat exchanger itself does not have to be tubular. The cooling method of the present invention may be a method using a refrigerant or a method not using a refrigerant.
As a cooling method that does not use a refrigerant, for example, a method of cooling the metal block using a metal block or the like penetrating a heavy oil flow path may be used. In this case, the metal block corresponds to a heat exchanger. The material of the metal block is not limited, but a material having high thermal conductivity is preferable, and examples thereof include copper, aluminum, iron, various alloys such as brass and stainless steel. Also, materials other than metal are not excluded.

The cooling method using a refrigerant is a method of exchanging heat by contacting heavy oil and a refrigerant through a heat transfer material. In this case, a heat exchanger is constituted by the heat transfer material and the refrigerant.
The shape of the heat transfer material is not limited, and examples thereof include a tubular shape (circular tubular shape, elliptical tubular shape, square tubular shape, other polygonal tubular shape, fin tube, etc.), flat plate shape, radiator shape, tank shape, and the like. Among these, a tubular shape is preferable in that heavy oil and refrigerant hardly stay.
When a tubular material is used as the heat transfer material (hereinafter, sometimes referred to as “heat transfer tube”), heavy oil may be flowed therein, or refrigerant may be flowed therein. From the viewpoint of cooling efficiency and ease of blocking the flow of the heavy oil, it is preferable to flow the heavy oil into the heat transfer tube.
As mentioned above, it is preferable that the heat exchanger in the present invention is a system in which a heat transfer tube is used, heavy oil flows through the inside thereof, and refrigerant flows through the outside.

<Heat exchanger>
As described above, there is no restriction on the cooling method applied to the present invention, but there is no restriction on the shape of the heat exchanger used for cooling.
When a heat transfer tube is used as a heat exchanger, the material is not limited and may be a metal or a non-metal, but is preferably a metal from the viewpoint of thermal conductivity. Examples of the metal used for the heat transfer tube include copper, aluminum, iron, titanium, zirconium, tantalum, niobium, and various alloys such as brass, aluminum bronze, cupronickel, carbon steel, stainless steel, cast iron, aluminum alloy, and titanium alloy. Etc. are exemplified. Examples of the nonmetal used for the heat transfer tube include glass, carbon, and ceramics. Among these, carbon steel and stainless steel are preferable.
In addition, the elbow, the joint, the branch pipe, the collecting pipe, the reducer, the coupling, the flange, and the like may be appropriately included in the portion of the heat transfer pipe. Therefore, the heat transfer tube may be a single line or may be assembled after branching.

The inner diameter (D) of the heat transfer tube is not limited, but the lower limit is usually 6 mm or more, preferably 8 mm or more, more preferably 10 mm or more. If the inner diameter of the heat transfer tube is less than the lower limit, heavy oil may be blocked in the heat transfer tube.
The upper limit of the inner diameter of the heat transfer tube is not limited, but is usually 30 mm or less, preferably 25 mm or less, more preferably 20 mm or less. If the inner diameter of the heat transfer tube exceeds the upper limit, it is difficult to sufficiently cool the heavy oil, and the temperature of the heavy oil after cooling may become uneven.
In addition, when the internal diameter of a heat exchanger tube changes, it means an average diameter.

The thickness of the heat transfer tube is not limited, but the lower limit is usually 0.5 mm or more, preferably 1.0 mm or more, more preferably 1.5 mm or more. As the thickness of the heat transfer tube is smaller (thin), the efficiency of heat exchange becomes better. On the other hand, there may be a problem that mechanical strength, corrosion resistance, workability and the like deteriorate.
The upper limit of the thickness of the heat transfer tube itself is not limited, but is usually 4.5 mm or less, preferably 3.5 mm or less, more preferably 2.5 mm or less. If the thickness of the heat transfer tube exceeds the upper limit, it may be difficult to sufficiently cool the heavy oil.
In addition, when the thickness of a heat exchanger tube changes, an average thickness is meant.

The length (L) of the heat transfer tube is not limited, but the lower limit is usually 10 cm or more, preferably 20 cm or more, more preferably 30 cm or more. When the length of the heat transfer tube is less than the lower limit, it may not be possible to obtain a uniformly cooled heavy oil.
Although the upper limit of the length of a heat exchanger tube is not limited, Usually, it is 1000 cm or less, Preferably it is 800 cm or less, More preferably, it is 500 cm or less. If the length of the heat transfer tube exceeds the upper limit, it may be difficult to transfer heavy oil, and it may be particularly difficult to discharge the heavy oil after cooling.
Here, the length of the heat transfer tube means a portion substantially corresponding to the step of cooling heavy oil in the present invention. That is, it means a portion where the flow of heavy oil is blocked during cooling and is in contact with the refrigerant. When the heat transfer tube is not a single line, it means the total length of the total extension.

The ratio (L / D) between the length (L) and the inner diameter (D) of the heat transfer tube used in the present invention is not limited, but the lower limit is usually 5 or more, preferably 15 or more, more preferably 30 or more, and still more preferably. Is 50 or more, particularly preferably 80 or more. When the L / D of the heat transfer tube is less than the lower limit, it may be difficult to sufficiently cool the heavy oil.
Although the upper limit of L / D of a heat exchanger tube is not limited, Usually, 1000 or less, Preferably it is 800 or less, More preferably, it is 500 or less, More preferably, it is 350 or less. If the L / D of the heat transfer tube exceeds the upper limit, it may be difficult to transfer heavy oil, and it may be particularly difficult to discharge the heavy oil after cooling.

The ratio (A / V (cm ⁻¹ )) between the surface area (Acm ² ) of the heat transfer tube inner surface used in the present invention and the volume (Vcm ³ ) in the heat transfer tube is not limited, but the lower limit is usually 1.0 or more. Preferably it is 1.5 or more, More preferably, it is 2.0 or more. When A / V of the heat transfer tube is less than the lower limit, it may be difficult to sufficiently cool the heavy oil.
Although the upper limit of A / V of a heat exchanger tube is not limited, Usually, 7 or less, Preferably it is 5 or less, More preferably, it is 4 or less. If the A / V of the heat transfer tube exceeds the above upper limit, it may be difficult to transfer heavy oil, and it may be difficult to discharge the heavy oil after cooling.

<Refrigerant>
The refrigerant used in the present invention is not limited, and may be a gas, a liquid, or a mixture thereof.
Examples of using a gas (including steam, mist, etc.) as the refrigerant include air, carbon dioxide (including dry ice), nitrogen, water vapor, chlorofluorocarbon, ammonia and the like, and air and water vapor are particularly preferable. .
Examples of the case where a liquid is used as the refrigerant include water, salt water, vegetable oil, animal oil, mineral oil, chemically synthesized oil, liquid nitrogen, acetone, ethylene glycol and the like, among which mineral oil and chemically synthesized oil are preferable.
As the refrigerant, one of the above may be used, or two or more may be used in combination.

<Blocking method>
In the present invention, the method of shutting off the flow when cooling heavy oil is not limited, and there is a method of shutting off with a shielding wall or temporarily storing the heat exchanger in a tank shape. When using a heat pipe, it is preferable to shut off by a shut-off valve. Using a heat transfer tube as a heat exchanger and shutting off the flow of heavy oil with a shut-off valve means that the structure is simple, there is little pressure loss, and heavy oil does not remain in the heat transfer tube. Is preferable.

The form of the shut-off valve used when shutting off the heavy oil flow is not limited, and examples thereof include a ball valve, a gate valve, a globe valve, a butterfly valve, a diaphragm valve, and the like. Among these, a ball valve and a gate valve are preferable. The use of a ball valve as the shut-off valve is preferable in terms of good shut-off performance and operability, and low pressure loss when fully opened.
When using a shut-off valve as a means for blocking the flow of heavy oil, it may be provided on either the upstream side or the downstream side of the heat exchanger, and may be provided on both, but it is preferable to provide both. Here, the upstream side and the downstream side of the heat exchanger are based on the direction of heavy oil flowing in the pipe. By providing stop valves on both the upstream and downstream sides of the heat exchanger, the heavy oil to be cooled becomes clear and mixing with heavy oil that is not to be cooled can be avoided during cooling. .

<Temperature of heavy oil>
In the present invention, the temperature of the heavy oil to be cooled (the temperature of the heavy oil before cooling) is not limited, but is usually 340 ° C. or lower, preferably 320 ° C. or lower, more preferably 300 ° C. or lower, more preferably 280 ° C. or lower. It is. When the temperature of the heavy oil to be used for cooling exceeds the upper limit, the cooling method of the present invention may not be sufficiently exhibited, and the heavy oil may be altered. The lower limit of the temperature of the heavy oil used for cooling is not limited, but is usually 120 ° C or higher, preferably 140 ° C or higher.

  In the present invention, the temperature of the heavy oil after cooling is not limited and may be appropriately set depending on the purpose, but is usually 260 ° C. or lower, preferably 220 ° C. or lower, more preferably 180 ° C. or lower. Although the minimum of the temperature of the heavy oil after cooling is not limited, Usually, 60 degreeC or more, Preferably it is 100 degreeC or more.

  In the present invention, the temperature difference between the heavy oil before and after cooling is not limited and may be appropriately set depending on the purpose, but is usually 40 ° C. or higher, preferably 80 ° C. or higher, more preferably 120 ° C. or higher, and still more preferably. Is 160 ° C. or higher. By adopting the present invention, efficient cooling is possible, and therefore it is possible to rapidly cool even under such a large temperature difference condition. Although the upper limit of the temperature difference of the heavy oil before and after cooling is not limited, it is usually 300 ° C. or lower, preferably 260 ° C. or lower, more preferably 220 ° C. or lower. When cooling is performed exceeding the upper limit temperature difference, the cooling method of the present invention may not be sufficiently exhibited, and further, the material life may be reduced due to thermal fatigue.

In the present invention, the cooling time of the heavy oil is not limited, but is usually 15 minutes or less, preferably 1
0 minutes or less, more preferably 5 minutes or less. If the present invention is adopted, efficient cooling is possible, and thus it is possible to rapidly cool in such a short time. The lower limit of the cooling time for the heavy oil is not limited, but is usually 60 seconds or longer, preferably 90 seconds or longer, more preferably 120 seconds or longer. When the cooling time of the heavy oil is less than the lower limit, the cooling may be insufficient, or the temperature of the heavy oil after cooling may be uneven.

<Discharge method>
In this invention, after cooling heavy oil by said method, the cooled heavy oil is discharged | emitted from a heat exchanger. The method for discharging the heavy oil from the heat exchanger is not limited, and the heavy oil may be extruded with the heavy oil before reaching the heat exchanger, or may be discharged using a substance other than the heavy oil.
When the cooled heavy oil is discharged by the heavy oil itself, heat exchange occurs at the boundary with the cooled heavy oil, so do not use the affected heavy oil part for the intended application. Is preferred.
When the cooled heavy oil is discharged as a substance other than the heavy oil, either a gas or a liquid may be used, but a gas is preferably used in order to avoid mixing with the heavy oil. Examples of the gas used for discharging heavy oil include inert gases such as nitrogen and argon, and air. Among these, inert gases are preferable.
In addition, as a specific aspect of using the liquid when discharging the heavy oil, there is a solvent when the heavy oil cooled by the present invention is dissolved or diluted in a solvent. In such a case, it is preferable to use an apparatus and a method that can quantitatively determine the amount ratio of the heavy oil to be discharged and the solvent to be used for discharging so that the dilution ratio becomes clear.

In the present invention, the use of power such as a fluid pump is not excluded when the cooled heavy oil is discharged from the heat exchanger. However, if the cooling method of the present invention is adopted, the pressure load is small and the cooling can be performed efficiently, so that it can be discharged only by the transfer pressure of the heavy oil itself flowing in the pipe.
In addition, when discharging | emitting the cooled heavy oil using liquid other than said gas or heavy oil, heavy oil can be discharged | emitted with the pressure of the said gas or liquid. There is no restriction | limiting in the pressure provided at the time of discharge | emission, What is necessary is just the pressure which can discharge | emit the heavy oil after cooling.

[3. Aspect of Cooling Method for Heavy Oil]
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is one embodiment of a method for cooling heavy oil by a heat exchanger using a heat transfer tube and a refrigerant.
The heat exchanger 1 includes a heat transfer tube 2 and a refrigerant C, and the refrigerant C exists in the cooling tank 3. Heavy oil in the heat transfer pipe 2 flows in from the heavy oil line pipe 4 and is discharged from the heavy oil line pipe 5.
In addition, the cooling tank 3 containing the refrigerant C and the heat transfer tube 2 may be integrated, but may have an independent structure. If the cooling tank 3 and the heat transfer tube 2 have independent structures, the heat transfer tube 2 can be immersed in the refrigerant C only when the heavy oil is cooled.

  The heavy oil line piping 4 is normally bypassed from the main piping in the production line. Moreover, it is preferable that the bypassed heavy oil line piping 4 has a structure that can be shut off from the main piping with a closing valve or the like. When the heavy oil according to the present invention is cooled irregularly or intermittently, if there is a concern that the heavy oil A is solidified or clogged in the heavy oil line piping 4, for example, the heavy oil is discharged from the main piping. It is preferable to suppress the above problem by setting the process leading to the quality oil line pipe 4 in the vertical direction.

Close valves 8 and 9 are provided in the vicinity of the heat transfer pipe 2 in the heavy oil line pipes 4 and 5, respectively. By closing the shutoff valves 8 and 9, the flow of the heavy oil A in the heat transfer tube 2 can be shut off.
Each of the heavy oil line pipes 4 and 5 branches near the heat transfer pipe 2. A shutoff valve is provided in the branch pipe of the heavy oil line pipe 4 so that a gas or a liquid for discharging the heavy oil can be introduced. Moreover, the solvent etc. for washing | cleaning the inside of the heat exchanger tube 2 can also be poured. A shutoff valve is also provided in the branch pipe of the heavy oil line pipe 5, and the fluid in the pipe can be taken out without flowing into the heavy oil pipe 5. By adopting such a structure, mixing of the heavy oil A that is cooled each time can be prevented, blockage in the heat transfer tube 2 can be prevented, and the heat transfer tube 2 can be cleaned.

The refrigerant C in the cooling tank 3 is adjusted in advance to the temperature of the heavy oil cooling target. The temperature adjustment of the refrigerant C may be performed by a temperature controller provided in the cooling tank 3 itself, or may be performed by an external temperature controller (not shown) by circulating the refrigerant C to the outside. Usually, a heater (heater) is used to set the refrigerant C to the initial temperature before the start of cooling, and a cooler (cooler) is used after the cooling of the heavy oil A is started.
In addition, it is preferable that the refrigerant C be stirred by providing the cooling tank 3 with a stirring function (not shown).
When the refrigerant C is externally circulated, it is discharged from the refrigerant line 7 and introduced from the refrigerant line 6. Although there is no restriction | limiting in the system of an external temperature controller, The cooling method using a refrigerant | coolant etc. are mentioned. The external temperature controller is usually used for the purpose of lowering the temperature of the refrigerant C that has risen due to the cooling of the heavy oil A, but is heated to set the refrigerant C to the initial temperature before starting the cooling of the heavy oil A. It may be used for purposes.

<Operation procedure>
The inside of the heat transfer tube 2 before the start of cooling may be empty or filled with heavy oil A, but from the viewpoint of preventing blockage of the heavy oil line piping and the heat transfer tube 2, It is preferable to be in a state.
Heavy oil A flows in from the heavy oil line piping 4 with the stop valves (for heavy oil cooling) 8 and 9 set to “open” and the stop valves (for purge) 10 and 11 set to “closed” in advance. The interior of the heat transfer tube 2 is filled with heavy oil A.
Next, the shutoff valves (for heavy oil cooling) 8 and 9 are closed to shut off the heavy oil line flow. This time is set as the start of the cooling time. In addition, when the cooling tank 3 and the heat exchanger tube 2 are independent structures, the time when the heat exchanger tube 2 is immersed in the refrigerant C is set as the start of the cooling time.
It is usually confirmed by a thermometer provided in the heat transfer tube 2 that the heavy oil A has reached the target temperature. The method of the thermometer is not limited, but a method such as a thermocouple type can be used. In addition, it is not necessary to monitor temperature every time by checking the temperature of the heavy oil A flowing out in advance.

When the temperature of the heavy oil A reaches the target temperature, the cooling is completed, and the cooled heavy oil B is discharged from the heat transfer tube 2.
When the cooled heavy oil B is pushed out and discharged by the heavy oil itself in the heavy oil line piping, the shut-off valves (for heavy oil cooling) 8 and 9 are set to “open”. At this time, when it is difficult to discharge the heavy oil B only by the pressure of the heavy oil line pipe 4 itself, the pressure may be increased.
When the cooled heavy oil B is discharged by the purge gas D or the like, the closing valve (for purging) 10 and the closing valve (for heavy oil cooling) 9 are set to “open”, and the purging gas D is closed (for purging). Press fit from 10 side. In this case, the discharge speed of the heavy oil B cooled by the pressure of the purge gas D can be adjusted.

  After the cooled heavy oil B is discharged from the heat transfer tube 2, the heat transfer tube 2 can be appropriately emptied or cleaned. In this case, the shutoff valves (for heavy oil cooling) 8 and 9 are set to “closed”, and the purge valves D and the like are closed to the shutoff valves (for purge) 10 while the shutoff valves (for purge) 10 and 11 are set to “open” Press fit from the side. When cleaning the inside of the heat transfer tube 2, a solvent or the like may be used instead of the purge gas D.

[4. Measurement using cooled heavy oil]
The purpose of use of the heavy oil cooled by the method of the present invention is not limited, but it is suitably used for quality inspection and process analysis in heavy oil production facilities. Specifically, it can be applied to gas chromatography, sulfur analysis, NMR, CHN elemental analysis, etc. in addition to analysis of solvent insolubles such as QI.
Moreover, when using for the above purposes, a cooled heavy oil and a solvent may be appropriately mixed and used. Further, as described above, when the cooled heavy oil is discharged from the heat exchanger, it may be mixed and used by discharging it with a solvent.

Below, after mixing the cooled heavy oil with a solvent, the method of measuring solvent insoluble content, such as QI, is demonstrated. As the measurement method, measurement by absorbance will be described, but the measurement method is not limited to this, and examples thereof include a method using a liquid fine particle counter (particle counter) and a method using a turbidimeter.
Although the solvent used for the measurement of a solvent insoluble content is not limited, For example, quinoline, toluene, N-methylpyrrolidone, pyridine, acetone, hexane, nitrobenzene, morpholine, chloroform, alcohol etc. are mentioned. Among these, quinoline, toluene, N-methylpyrrolidone, and hexane are preferable from the viewpoint of solubility in heavy oil, and quinoline is particularly preferable.
The component composition in heavy oil can also be analyzed in more detail by measuring the insoluble matter for each solvent using different solvents. A mixed solvent may be used.

  The dilution ratio of the solvent with respect to heavy oil (weight of solvent / weight of heavy oil) is not limited, but is usually 100 to 10,000 times, preferably 500 to 5000 times, more preferably 1000 to 3000 times, and still more preferably 1200. It is desirable to be -2000 times. If the dilution factor is too low, the measurement accuracy may decrease. Furthermore, the solubility in a solvent becomes saturated, and the accurate content of solvent insolubles may not be measured. On the other hand, even when the dilution rate is too high, the accurate content of solvent-insoluble components may not be measured.

When the method for measuring absorbance is adopted, the content of the solvent-insoluble component in the mixed solution (measurement sample) of the cooled heavy oil and the solvent is in the range from the wavelength range of visible light to the wavelength range of infrared light. The absorbance can be calculated using an absorptiometer capable of measuring the absorbance.
That is, irradiating the measurement sample with a predetermined one light in the wavelength region of infrared light from the wavelength of visible light, measuring the absorbance at that wavelength, and calculating the content ratio of the solvent-insoluble content from the absorbance. Can do. In addition, the measurement sample is irradiated with light in the wavelength region from visible light to near-infrared light and infrared light, the absorbance at each wavelength is measured, and the solvent-insoluble content is contained from the ratio of absorbance. The ratio can also be calculated.

By using an absorbance measurement sensor based on visible, near infrared or infrared spectrum, it can be applied to heavy oils with color changes that are not good for light and laser measurement methods. Thus, it can be used for solvent insoluble content measurement of heavy oil containing multiple components. An example of such an absorbance measurement sensor is Chino Co., Ltd .: IM series Model 3192.
The cell used for the absorbance measurement is not limited, and a commercially available liquid cell for visible and infrared analysis can be used. Moreover, it is also possible to install a flow cell in a spectroscope and to continuously measure the solvent insoluble content in the sample by passing the sample continuously therethrough.

When the method for measuring absorbance is employed, it is preferable to use a region of 400 to 1500 nm or 1700 to 2500 nm as the measurement wavelength region. Specifically, the measurement sample is irradiated with either one wavelength (λ1) selected from at least 400 to 1500 nm or one wavelength (λ2) selected from 1700 to 2500 nm, and a spectrum transmitted through the measurement sample is detected. The absorbance is calculated from this.

Among the above measurement wavelengths, the visible light to near infrared light region is preferably 700 to 1300 nm, more preferably 900 to 1100 nm, and even more preferably 950 to 1050 nm. When QI is measured using quinoline as a solvent, if a wavelength of less than 700 nm is used, it tends to be susceptible to a change in absorbance due to deterioration of quinoline.
Among the above measurement wavelengths, the infrared light region is preferably 1800 to 1900 nm or 2000 to 2150 nm. In the infrared light region, when a region other than these wavelength regions, specifically, a wavelength exceeding 1400 to 1600 nm, 1910 to 1990 nm, and 2200 nm is used, quinoline absorbs moisture when QI is measured using quinoline as a solvent. The absorbance tends to change under the influence of

  When obtaining the absorbance, usually, a solvent or air is measured in advance as a reference sample, and the absorbances Kλ1 and Kλ2 corresponding to the respective wavelengths are calculated from the measured value of the sample and the measured sample, for example, from the formula (I). Then, the solvent-insoluble content ratio can be measured from the absorbance (Kλ1, Kλ2) at λ1 or λ2. Further, the solvent-insoluble content ratio can be calculated from the ratio (Kλ2 / Kλ1) of the absorbance at λ1 (Kλ1) and the absorbance at λ2 (Kλ2).

Kλ1, which is the absorbance in the visible light to near infrared light region, is associated with the absorbance of the solvent, and Kλ2, which is the absorbance in the infrared light region, can be associated with the absorbance of the solvent insoluble matter. For this reason, if the measurement wavelengths of λ1 and λ2 are appropriately selected, the influence of temperature in infrared absorption can be reduced by using these ratios (Kλ2 / Kλ1) as a scale, and the content ratio of solvent-insoluble matter can be further increased. It can be measured accurately.
When calculating the content ratio of the solvent-insoluble component from the above ratio (Kλ2 / Kλ1), it is preferable to target the measurement sample having the ratio of 0.01 to 1, preferably 0.015 to 0.8. Is more preferably 0.02 to 0.6, and further preferably 0.025 to 0.4.

  The content of the solvent-insoluble component contained in the measurement sample is preferably 0.1% by weight to 70% by weight, and more preferably 1% by weight to 30% by weight. If the solvent-insoluble content is too low, there may be a problem that it is not possible to obtain sufficient absorbance to measure the solvent-insoluble content of the measurement sample. On the other hand, if the content ratio of the solvent-insoluble component is too high, there may be a problem that the infrared rays to be irradiated do not reach the light receiving unit.

  The spectrum of a predetermined wavelength transmitted from the light source of the infrared spectrometer reaches the light receiving portion while being attenuated and attenuated by molecules in the sample solution. Since the infrared transmitted light reaching this light receiving part is proportional to the solvent-insoluble content in the sample solution, the absorbance is calculated from the measured transmitted light, and the solvent-insoluble content is determined from the obtained absorbance. Can be calculated.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

<Example 1>
[Heat exchanger]
A heat exchanger according to the structure shown in FIG. 1 was used. Details of the heat exchanger are shown below. The heat exchanger tube of the heat exchanger was connected to a heavy oil line (manufactured by SUS316) at the front and back, and a closing valve (ball valve) was provided at the connection portion.
Heat transfer tube: The material is SUS316, the inner diameter (D) is 10 mm, the tube thickness is 1 mm, the length of the heat transfer tube immersed in the refrigerant (L) is 130 cm (L / D = 130, A / V = 4.0 cm ⁻¹ )
・ Cooling tank: A constant temperature tank with a capacity of about 20L equipped with a heater capable of controlling the temperature at ± 0.2 ° C and a uniform temperature inside the tank using a jet stirrer. Refrigerant: Mineral oil based heat composed of petroleum hydrocarbons. About 13.5L of medium (specific heat at 140 ° C is 2.4 kJ / kg · K) • Thermometer: A thermometer (K-type thermocouple) is installed in the heat transfer tube and in the cooling tank (immersed in the refrigerant). The temperature measured with the thermometer is recorded with a data logger.

[Temperature controller for refrigerant]
The temperature control of the refrigerant in the heat exchanger was performed by the following refrigerant temperature controller.
・ Cooler: High / low temperature circulator with cooling capacity of 200W (20 ℃) ・ Refrigerant: Polyethylene glycol ・ Heat transfer tube: Material is SUS316, inner diameter (D) 6mm, tube thickness 1mm circular tube

[Cooling method and results]
The temperature of the refrigerant in the heat exchanger was adjusted to 135 ° C. in advance and stirred in the cooling tank. On the other hand, the temperature of the refrigerant (polyethylene glycol) in the refrigerant temperature controller was adjusted to 100 ° C., and when the temperature of the refrigerant (mineral oil-based heat medium) in the heat exchanger rose, the temperature could be adjusted by cooling.
Next, the heavy oil adjusted to 310 ° C. (coal tar pitch generated from the coke production facility (viscosity at 100 ° C. measured with a B-type viscometer: 1284 mPa · s)) was transferred from the heavy oil line piping, and the heat exchanger It flowed into the heat transfer tube.
When the heavy oil was filled into the heat transfer tube, the shut valves before and after the heat transfer tube were closed to block the heavy oil flow.
The time when the heavy oil flow was interrupted was defined as “time zero”, and the temperature of the heavy oil and the temperature of the refrigerant in the heat exchanger were measured over time.
When the temperature of the heavy oil was cooled to 140 ° C., the cooling was completed. Thereafter, the closed valves before and after the heat transfer tubes were opened, and nitrogen was used as a purge gas to extract the cooled heavy oil.
The correlation between the cooling time and the heavy oil temperature is shown in FIG. The temperature of the heavy oil could be cooled from 310 ° C. to 140 ° C. in 4 minutes and 2 seconds (242 seconds).

<Reference example>
In order to examine the cooling efficiency in a state where heavy oil is flowing, estimation was performed by calculation as follows. The premise of the calculation is shown below.
[Heat exchanger]
It was set as the double pipe heat exchanger which is a circular pipe whose inner diameter of a shell is 23 mm, and the detail was set as follows.
・ Heat transfer tube: Material is SUS316 (thermal conductivity 14 J / m · s · K), inner diameter (D) 10 mm, tube thickness 1 mm round tube • Refrigerant: Mineral oil-based heat transfer medium composed of petroleum hydrocarbon ( The viscosity at 135 ° C. is 2.45 mPa · s, the density at 135 ° C. is 0.783 g / cm ³ , and the specific heat at 135 ° C. is 2
. 4kJ / kg · K, thermal conductivity at 135 ° C is 0.127J / m · s · K, dirt coefficient 0.000258m ² · K / W)
[Heavy oil]
Coal tar pitch generated from coke production facility (viscosity at 100 ° C. is 1241 mPa · s, density at 100 ° C. is 1.200 g / cm ³ , specific heat at 100 ° C. is 1.34 kJ / kg · K, thermal conductivity at 100 ° C. Is 0.14 J / m · s · K, dirt coefficient 0.004176 m ² · K / W)

<Reference Example 1>
The heavy oil inlet temperature was 310 ° C. The flow rate of the refrigerant was constant at 1000 kg / hr (278 cm ³ / s), and the refrigerant temperature was constant at 135 ° C. from the heat exchanger inlet to the outlet.
The heat exchanger length was set to 1.3 m, and convergence calculation was performed using the heavy oil outlet temperature and the heavy oil film viscosity as variables.
FIG. 3 shows changes in the outlet temperature (cooling temperature) of the heavy oil when the flow rate (flow velocity) of the heavy oil is changed. Further, FIG. 4 shows the outlet temperature (cooling temperature) of the heavy oil with respect to the time during which the heavy oil passes through the heat transfer tube.
From FIG. 3 and FIG. 4, the outlet temperature (cooling temperature) of the heavy oil is lowered by reducing the flow rate of the heavy oil and extending the time for passing through the heat transfer tube. However, under the condition that the length of the heat transfer tube was 1.3 m as in Example 1, the outlet temperature (cooling temperature) of the heavy oil was 168 ° C. when the passage time of the heat transfer tube was 4 minutes and 2 seconds. . This is 28 ° C. higher than in Example 1 in which the flow of heavy oil is blocked, and thus sufficient cooling has not been achieved.
Although it is computationally possible to lower the heavy oil outlet temperature by further reducing the heavy oil flow rate, it is actually difficult to stably feed at such a low flow rate. is there.

<Reference Example 2>
Convergence calculation was performed in the same manner as in Reference Example 1 except that the flow rate (flow velocity) of heavy oil was constant at 20 kg / hr and the length of the heat transfer tube of the heat exchanger was changed.
FIG. 5 shows changes in the outlet temperature (cooling temperature) of the heavy oil when the length of the heat transfer tube is changed. Further, FIG. 6 shows the outlet temperature (cooling temperature) of the heavy oil with respect to the time during which the heavy oil passes through the heat transfer tube.
From FIG.5 and FIG.6, the exit temperature (cooling temperature) of heavy oil is falling by lengthening a heat exchanger tube and lengthening the time which passes a heat exchanger tube. However, the length of the heat transfer tube necessary for cooling the heavy oil from 310 ° C. to 140 ° C. was about 40 m, and it took 10 minutes and 54 seconds to pass through the heat exchanger. Although it is possible in calculation to set the heat transfer tube of the heat exchanger to 40 m, it is actually difficult to feed heavy oil.

1 Heat Exchanger 2 Heat Transfer Tube 3 Cooling Tank 4 Heavy Oil Line Piping (Inlet)
5 Heavy oil line piping (exit)
6 Refrigerant line (inlet)
7 Refrigerant line (exit)
8 Stop valve (for heavy oil cooling)
9 Stop valve (for heavy oil cooling)
10 Close valve (for purging)
11 Close valve (for purging)
A Heavy oil B Heavy oil (after cooling)
C Refrigerant D Purge gas E Waste liquid

Claims (11)

  A method of cooling heavy oil flowing in a pipe using a heat exchanger, in which the heavy oil is cooled without flowing, and after the heavy oil is cooled, the heavy oil is heat-exchanged. A method for cooling heavy oil, characterized in that it is discharged from a vessel.   2. The method for cooling heavy oil according to claim 1, wherein the heat exchanger includes a heat transfer tube having a ratio (L / D) of a tube length L to a tube diameter D of 5 or more.   The heavy oil cooling method according to claim 2, wherein heat exchange is performed in a state where heavy oil is present inside the heat transfer tube and refrigerant is present outside the heat transfer tube.   The heavy oil cooling method according to any one of claims 1 to 3, wherein the heavy oil has a viscosity of 15 to 15000 mPa · s at 100 ° C.   The method for cooling heavy oil according to any one of claims 1 to 4, wherein the temperature difference between the heavy oil before cooling and the temperature after cooling is 40 to 300 ° C.   The method for cooling heavy oil according to any one of claims 1 to 5, wherein the blocking is performed by a shut-off valve.   The method for cooling heavy oil according to any one of claims 1 to 6, wherein the discharge is performed by press-fitting heavy oil or gas.   The heavy oil cooling method according to any one of claims 1 to 7, wherein the heavy oil is at least one selected from coal tar, coal tar pitch, or petroleum-based pitch.   The method for cooling heavy oil according to any one of claims 1 to 8, wherein the refrigerant contains any one selected from vegetable oil, animal oil, mineral oil, chemically synthesized oil, air, water, and steam.   A heat exchanger that cools heavy oil using a heat transfer tube having a ratio of the tube length L to the tube diameter D (L / D) of 5 or more, and the heat transfer tube is filled with the heavy oil. A heavy oil heat exchanger having a mechanism for shutting off and cooling the flow of the heavy oil and discharging the heavy oil after being cooled.   A solvent is mixed with the heavy oil cooled by the method according to any one of claims 1 to 9, and the insoluble content in a mixed solution of the heavy oil and the solvent is measured. Ratio measurement method.

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