Apparatus for producing treated oil for crude oil blending, method for producing treated oil for crude oil blending, and treated oil for crude oil blending

Abstract

Provided is an apparatus for mixing recovered light hydrocarbon, recovered by centrifugation from crude oil sludge, with crude oil and producing a treated oil for crude oil blending, the apparatus for producing treated oil for crude oil blending being characterized by having: a recovered light hydrocarbon storage apparatus for storing the recovered light hydrocarbon in a state heated to or above a temperature that keeps the recovered light hydrocarbon fluid and permits delivery by liquid delivery pump; a first blending apparatus for blending recovered light hydrocarbon and crude oil and obtaining a first blended liquid; a recovered light hydrocarbon supply pipe; a recovered light hydrocarbon discharge apparatus; a first crude oil separation pipe; a first flow rate control apparatus; a second blending apparatus for blending the first blended liquid with crude oil and obtaining a treated oil for crude oil blending; a first blended liquid supply pipe; a first heating apparatus for heating the first blended liquid to a temperature above the precipitation oil of the first blended liquid; a second crude oil separation pipe; and a second flow rate control apparatus. According to the present invention, it is possible to provide a method for treating a recovered light hydrocarbon which is less likely to generate sludge due to the recovered light hydrocarbon in a blended crude oil when blended with crude oil.

Description

Manufacturing apparatus for crude oil blended processed oil, manufacturing method for crude oil blended processed oil, and crude oil blended processed oil

[0001] The present invention relates to a method and an apparatus for producing treated oil for crude oil blending, which is used to blend oil recovered from crude oil sludge accumulated in a crude oil tank where crude oil is stored with the treated oil.

[0002] Crude oil sludge accumulated in crude oil tanks is generally treated as industrial waste after being removed from the tank, but this disposal process is expensive. On the other hand, crude oil sludge often contains approximately 30 to 80% by volume of oil, so there is a great need to recover the oil from crude oil sludge. For this reason, attempts have been made to recover oil from crude oil sludge using methods such as vacuum distillation, thermal separation, and centrifugal separation.

[0003] However, since the oil recovered from crude oil sludge is of low quality, using it as feedstock to produce high-quality fuel would result in high refining costs, so the oil recovered from crude oil sludge is often used directly as inexpensive fuel oil.

[0004] Attempts have been made to mix oil recovered from crude oil sludge with crude oil to turn it back into more expensive crude oil rather than cheap fuel oil. However, because oil recovered from crude oil sludge has low fluidity and poor compatibility with crude oil, mixing oil recovered from crude oil sludge directly with crude oil is likely to result in sludge formation again.

[0005] Therefore, Patent Document 1 discloses a method for recovering oil from crude oil sludge that is unlikely to generate sludge again even when the oil recovered from crude oil sludge is mixed with crude oil, and includes a first step (1) of mixing crude oil sludge (A) and crude oil (B) so that the ratio of the crude oil sludge (A) to the total of the crude oil sludge (A) and the crude oil (B) is 20 to 95 mass %, and then heating and stirring the mixture of crude oil sludge (A) and crude oil (B) at 40 to 200°C to obtain a heated and stirred product of the crude oil sludge (A) and crude oil (B); a second step (1) of centrifuging the heated and stirred product at 40 to 200°C to separate the light liquid from the heavy components and obtain the light liquid; and a third step (1) of raising the temperature of the light liquid to a temperature above its melting point and mixing the light liquid at a temperature above its melting point with crude oil (C) in a crude oil transfer pipe, wherein the temperature of the crude oil (C) is either above that of the light liquid or lower than that of the light liquid and the temperature difference between the light liquid and the crude oil (C) is within 40°C.

[0006] International Publication No. 2016 / 199692

[0007] When the method of Patent Document 1 is applied directly to a crude oil storage facility, it is conceivable to install a line mixer in a crude oil transfer pipe (hereinafter also referred to as a crude oil process line) and directly mix the light recovered oil fraction (hereinafter referred to as recovered hydrocarbon light liquid) obtained from crude oil sludge by centrifugal separation with the crude oil.

[0008] However, the inventors have conducted studies and found that when the recovered hydrocarbon light liquid is directly introduced into a crude oil process line, it must be preheated beforehand to prevent the formation of precipitates that could cause sludge in the recovered hydrocarbon light liquid. However, even if the recovered hydrocarbon light liquid is dispersed using a line mixer during mixing, if the recovered hydrocarbon light liquid experiences a sudden drop in temperature in a large crude oil process line, precipitates derived from the recovered hydrocarbon light liquid will form, and ultimately, sludge will be likely to form in the crude oil mixed with the recovered hydrocarbon light liquid, with the precipitates acting as nuclei. Furthermore, there is a concern that the introduction of high-temperature hydrocarbon light liquid may cause local heating in the crude oil process line, resulting in the vaporization of light components.

[0009] Therefore, an object of the present invention is to provide a method for treating recovered hydrocarbon light liquids that is less likely to produce sludge in the mixed crude oil even when the recovered hydrocarbon light liquid obtained from crude oil sludge by centrifugal separation is mixed with crude oil.

[0010] Therefore, the inventors conducted research and found that a blended oil (hereinafter referred to as "processed oil for crude oil blending") obtained by diluting recovered hydrocarbon light liquid with crude oil in two or more stages under predetermined temperature conditions before blending with crude oil in a crude oil process line is less likely to produce precipitates even when the temperature drops, and does not increase the amount of sludge generated even when this is mixed with crude oil at approximately room temperature. Furthermore, because the blended oil is not added to or mixed with crude oil in a heated state, it is also possible to prevent local heating of the crude oil in the crude oil process line.

[0011] That is, the present invention (1) is an apparatus for producing a treated oil for crude oil blending by mixing a recovered hydrocarbon light liquid recovered from crude oil sludge by centrifugation with crude oil, and comprises at least: a recovered hydrocarbon light liquid storage device for storing the recovered hydrocarbon light liquid in a heated state at a temperature at which the recovered hydrocarbon light liquid can be maintained in fluidity and at a temperature at which it can be fed by a liquid feed pump or higher; a first mixing device for mixing the recovered hydrocarbon light liquid with crude oil separated from a crude oil process line to obtain a first mixed liquid; a recovered hydrocarbon light liquid supply pipe connecting the recovered hydrocarbon light liquid storage device and the first mixing device; a recovered hydrocarbon light liquid delivery device provided on the recovered hydrocarbon light liquid supply pipe; a first crude oil fractionation pipe branching from the crude oil process line and connected to the first mixing device; a first flow rate control device provided on the first crude oil fractionation pipe; a second mixing device for mixing the first mixed liquid with crude oil separated from the crude oil process line or the first crude oil fractionation pipe to obtain a treated oil for crude oil blending; a first mixed liquid delivery pipe connecting the first mixing device and the second mixing device; a first heating device provided in the first mixed liquid delivery pipe for heating the first mixed liquid to a temperature equal to or higher than the deposition point of the first mixed liquid; a second crude oil collection pipe branching off from the crude oil process line or the first crude oil collection pipe and connected to the second mixing device; and a second flow rate control device provided in the second crude oil collection pipe.

[0012] The present invention (2) also provides an apparatus for producing processed oil for blending with crude oil according to (1), characterized in that the first mixer and the second mixer are line mixers.

[0013] The present invention (3) also provides a manufacturing apparatus for crude oil blending treated oil according to (1) or (2), characterized in that it has a third mixing device for mixing the crude oil blending treated oil with crude oil in the crude oil process line.

[0014] The present invention (4) also provides a method for producing a treated oil for crude oil blending, comprising: a recovered hydrocarbon light liquid storage step of storing a recovered hydrocarbon light liquid recovered by centrifuging crude oil sludge (A) or a mixture of crude oil sludge (A) and crude oil (B) in a state where the recovered hydrocarbon light liquid is heated to a temperature at which the fluidity of the recovered hydrocarbon light liquid is maintained and at least a temperature at which the recovered hydrocarbon light liquid can be fed by a liquid feed pump; a first mixing step of mixing the recovered hydrocarbon light liquid with crude oil (C) separated from a process line for crude oil (C) to obtain a first mixed liquid; a first heating step of heating the first mixed liquid to a temperature at least the precipitation point of the first mixed liquid; and a second mixing step of mixing the first mixed liquid heated in the first heating step with crude oil (C) separated from the process line for crude oil (C) to obtain a treated oil for crude oil blending.

[0015] The present invention (5) also provides a method for producing a treated oil for blending with crude oil according to (4), characterized in that the recovered hydrocarbon light liquid is obtained by carrying out: a crude oil sludge heating treatment step (1) of mixing the crude oil sludge (A) and the crude oil (B) so that the proportion of the crude oil sludge (A) relative to the total of the crude oil sludge (A) and the crude oil (B) is 20% by mass or more, and then heating and stirring the mixture of the crude oil sludge (A) and the crude oil (B) at 40 to 200°C to obtain a heated and stirred product of the crude oil sludge (A) and the crude oil (B); and a centrifugation step (1) of centrifuging the heated and stirred product at 40 to 200°C to separate the light liquid from the heavy components and obtain the recovered hydrocarbon light liquid.

[0016] The present invention (6) also provides a method for producing treated oil for blending with crude oil according to (4) or (5), characterized by: a crude oil sludge heat treatment step (2) of heating the crude oil sludge (A) at 40 to 200°C to obtain a heat-treated crude oil sludge (A); and a centrifugation step (2) of centrifuging the heat-treated crude oil sludge at 40 to 200°C to separate the light liquid from the heavy components and obtain a recovered hydrocarbon light liquid, thereby obtaining the recovered hydrocarbon light liquid.

[0017] The present invention (7) also provides a method for producing a processed oil for crude oil blending according to any one of (4) to (6), characterized in that it comprises a third mixing step of mixing the processed oil for crude oil blending with crude oil (C) in a process line for the crude oil (C).

[0018] The present invention (8) also provides a processed oil for blending with crude oil, which is obtained by any one of the methods (4) to (7) for producing a processed oil for blending with crude oil.

[0019] According to the present invention, a method for treating recovered hydrocarbon light liquid can be provided in which, even when the recovered hydrocarbon light liquid obtained from crude oil sludge by centrifugal separation is mixed with crude oil, sludge caused by the recovered hydrocarbon light liquid is unlikely to occur in the mixed crude oil.

[0020] 1 is a schematic flow diagram showing an apparatus for producing processed oil for blending with crude oil according to an embodiment of the present invention.

[0021] The apparatus for producing treated oil for crude oil blending of the present invention is an apparatus for blending recovered hydrocarbon light liquid recovered from crude oil sludge (A) by centrifugation with crude oil (C) to produce treated oil for crude oil blending, and comprises at least: a recovered hydrocarbon light liquid storage apparatus for storing the recovered hydrocarbon light liquid in a heated state to a temperature at which the recovered hydrocarbon light liquid can be maintained in fluidity and at a temperature at which it can be fed by a liquid feed pump or higher; a first mixing apparatus for mixing the recovered hydrocarbon light liquid with crude oil separated from the process line for crude oil (C) to obtain a first mixed liquid; a recovered hydrocarbon light liquid supply pipe connecting the recovered hydrocarbon light liquid storage apparatus and the first mixing apparatus; a recovered hydrocarbon light liquid delivery apparatus provided in the recovered hydrocarbon light liquid supply pipe; a first crude oil fractionation pipe branching off from the process line for crude oil (C) and connected to the first mixing apparatus; and a first flow rate control apparatus provided in the first crude oil fractionation pipe. and a second flow control device provided in the second crude oil fractionation pipe. The process line for crude oil (C) in this invention refers to a transfer pipe for transferring crude oil that has been extracted from an oil field and subsequently processed in an oil-water separation or desalter to a crude oil tank.

[0022] The manufacturing apparatus and manufacturing method for crude oil blended according to the present invention will be described with reference to Figure 1. Figure 1 is a schematic flow diagram showing an embodiment of the manufacturing apparatus for crude oil blended according to the present invention, and is attached to a crude oil process line. In Figure 1, the manufacturing apparatus for crude oil blended according to the present invention includes a recovered hydrocarbon light liquid storage unit 1, a first mixer 2, a second mixer 4, a third mixer 5, a recovered hydrocarbon light liquid supply pipe 21 connecting the recovered hydrocarbon light liquid storage unit 1 and the first mixer 2, a first crude oil collection pipe 23 branching from the crude oil (C) process line 26 and connecting to the first mixer 2, a first mixed liquid delivery pipe 22 connecting the first mixer 2 and the second mixer 4, a second crude oil collection pipe 25 branching from the first crude oil collection pipe 23 and connecting to the second mixer 4, and a crude oil blended treated oil delivery pipe 24 connecting the second mixer 4 and the third mixer 5. A recovered hydrocarbon light liquid delivery device 7 is installed in the recovered hydrocarbon light liquid supply pipe 21, a first flow rate control device 8 is installed in the first crude oil collection pipe 23, a first heating device 3 is installed in the first mixed liquid delivery pipe 22, and a second flow rate control device 9 is installed in the second crude oil collection pipe 25.

[0023] In the recovered hydrocarbon light liquid storage device 1, recovered hydrocarbon light liquid 11 recovered by centrifugation from crude oil sludge (A), more specifically, recovered hydrocarbon light liquid 11 recovered by centrifugation from crude oil sludge (A) or a mixture of crude oil sludge (A) and crude oil (B), is stored in a heated state at a temperature at which it maintains fluidity and can be sent by a liquid feed pump or higher. First, the recovered hydrocarbon light liquid 11 heated in the recovered hydrocarbon light liquid storage device 1 is sent to a first mixer 2 using a recovered hydrocarbon light liquid delivery device 7, and crude oil (C) 14 is extracted from the process line 26 for crude oil (C) using a first flow rate control device 8 and sent to the first mixer 2, where the recovered hydrocarbon light liquid 11 and crude oil (C) 14 are mixed to obtain a first mixed liquid 12. Next, the obtained first mixed liquid 12 is heated in a first heating device 3 to a temperature equal to or higher than the crystallization point of the first mixed liquid 12, and the heated first mixed liquid 12 is sent to a second mixing device 4. At the same time, using a second flow control device 9, crude oil (C) 14 is extracted from a second crude oil collection pipe 23 and sent to the second mixing device 4. In the second mixing device 4, the first mixed liquid 12 and the crude oil (C) 14 are mixed to obtain a processed oil for crude oil blending 13. Next, the obtained processed oil for crude oil blending 13 is sent to a third mixing device 5 and mixed with the crude oil (C) 14 in a process line 26 for crude oil (C). Then, the crude oil (C) 15 mixed with the processed oil for crude oil blending 13 is transferred to a crude oil tank 6 and stored.

[0024] The apparatus for producing processed oil for crude oil blending of the present invention is an apparatus for producing processed oil for crude oil blending by mixing a recovered hydrocarbon light liquid recovered from crude oil sludge (A) by centrifugation with crude oil (C). In other words, the apparatus for producing processed oil for crude oil blending of the present invention is an apparatus for heating and stirring the crude oil sludge (A) or mixing the crude oil sludge (A) and crude oil (B), heating and stirring the resulting mixture, then centrifuging the crude oil sludge (A) or the mixture of the crude oil sludge (A) and crude oil (B) in the heated state to separate the recovered hydrocarbon light liquid as a light fraction, and then mixing the resulting recovered hydrocarbon light liquid with crude oil (C) separated from a process line for crude oil (C) to produce processed oil for crude oil blending.

[0025] The recovered hydrocarbon light liquid to be treated contains dissolved deposit-causing substances that are the source of deposits that cause sludge when mixed with crude oil under heated conditions, and as the temperature drops, deposits that cause sludge when mixed with crude oil are precipitated. The main component of these deposits that cause sludge is wax. The wax content in the recovered hydrocarbon light liquid is not particularly limited, but is preferably 0.1 to 10.0 mass%, more preferably 0.1 to 8.0 mass%.

[0026] The manufacturing apparatus for crude oil blending processed oil of the present invention is an apparatus for producing, from recovered hydrocarbon light liquid and crude oil (C), a crude oil blending processed oil that is sent into a process line for crude oil (C) and mixed with the crude oil (C) in the process line for crude oil (C).

[0027] Crude oil sludge (A) is sludge generated from crude oil stored in a crude oil tank and deposited at the bottom of the crude oil tank. Examples of crude oil sludge (A) include crude oil sludge generated from crude oil stored in a crude oil tank after solids and water have been removed after crude oil extraction and stored in a crude oil tank before being shipped to a refinery and deposited at the bottom of the crude oil tank; crude oil sludge deposited at the bottom of a crude oil tank of a crude oil tanker; and crude oil sludge generated from crude oil in a crude oil storage tank before being refined at a refinery and deposited at the bottom of the crude oil tank. Crude oil sludge (A) may be generated from one type of crude oil or may be generated from multiple types of crude oil.

[0028] The crude oil sludge (A) contains oil, asphaltene, iron, sand, water, etc. The oil in the crude oil sludge (A) is mainly paraffin and aromatic hydrocarbons having 40 or more carbon atoms. The oil in the crude oil sludge (A) is recovered from the crude oil sludge (A) by dissolving it in a recovered hydrocarbon light liquid obtained by mixing the crude oil sludge (A) with crude oil (B), heating, and centrifuging the mixture.

[0029] The crude oil sludge (A) deposited in the crude oil tank is removed from the crude oil tank and mixed with crude oil (B). The method for removing the crude oil sludge (A) from the crude oil tank is not particularly limited, and examples thereof include a method (COW: Crude Oil Washing) in which the crude oil in the crude oil tank is removed from the crude oil tank, and then high-pressure crude oil is injected onto the crude oil sludge (A) deposited in the crude oil tank, and the crushed or partially dissolved crude oil sludge (A) is pushed out of the crude oil tank by the crude oil, and a method in which the crude oil in the crude oil tank is removed from the crude oil tank, and then the crude oil sludge (A) deposited in the crude oil tank is manually removed.

[0030] The crude oil (B) to be mixed with the crude oil sludge (A) is not particularly limited, and may be crude oil after extraction and before solids, water, etc. are removed and the crude oil is stored in a crude oil tank, or crude oil that has been extracted and recently stored in a crude oil tank after solids, water, etc. are removed and before crude oil sludge is generated, or crude oil that is the supernatant in a crude oil tank after crude oil sludge has been generated at the bottom of the crude oil tank due to storage in the crude oil tank for a certain period of time. The crude oil (B) may be the same type of crude oil as the crude oil from which the crude oil sludge (A) was produced, or a different type of crude oil.

[0031] When crude oil sludge (A) is removed from a crude oil tank by pushing the crude oil sludge (A) out of the crude oil tank with crude oil (for example, COW), what is removed from the crude oil tank is a mixture of the crude oil sludge (A) and the crude oil used to remove the crude oil sludge (A), and in this case, the crude oil used to remove the crude oil sludge (A) is included in crude oil (B).

[0032] The crude oil (C) to be mixed with the recovered hydrocarbon light liquid is not particularly limited, and may be crude oil after extraction before solids, water, etc. are removed and the crude oil is stored in a crude oil tank; crude oil that has been extracted and stored in a crude oil tank shortly after solids, water, etc. are removed and before crude oil sludge is generated; or crude oil that is the supernatant in a crude oil tank after crude oil sludge is generated at the bottom of the crude oil tank due to storage in the crude oil tank for a certain period of time. The crude oil (C) may be the same type of crude oil as the crude oil from which the crude oil sludge (A) was generated, or a different type of crude oil. The crude oil (C) may be the same type of crude oil as the crude oil (B) or a different type of crude oil.

[0033] The recovered hydrocarbon light liquid contains a large amount of deposit-causing substances that were contained in the crude oil sludge (A) and that cause deposits when the temperature drops to low levels. Therefore, it is necessary to maintain the fluidity of the recovered hydrocarbon light liquid by setting the temperature at or above "a temperature at which the fluidity of the recovered hydrocarbon light liquid can be maintained and the liquid can be transported by a liquid transport pump." The recovered hydrocarbon light liquid storage device is a device for storing the recovered hydrocarbon light liquid in a state where it is heated to or above "a temperature at which the fluidity of the recovered hydrocarbon light liquid can be maintained and the liquid can be transported by a liquid transport pump." The recovered hydrocarbon light liquid storage device has a heating device such as a steam coil or steam trace, and may also have a stirring device, a tank mixer, and a circulation pump.

[0034] The first mixer is a device for mixing the recovered hydrocarbon light liquid with crude oil (C) separated from the crude oil (C) process line to obtain a first mixed liquid. The first mixer is not particularly limited, and examples thereof include a line mixer. The recovered hydrocarbon light liquid is highly viscous, and static mixers, mixing valves, etc. tend to cause pressure differentials and adhesion due to temperature drops, so a line mixer is preferred. Mixing using a line mixer makes it easy to uniformly disperse and mix the recovered hydrocarbon light liquid into the crude oil. As a result, even when the temperature drops, substances (mainly wax components) that cause deposits are less likely to grow into large crystals and deposit, which ultimately makes it easier to suppress the generation of sludge in the crude oil mixed with the recovered hydrocarbon light liquid.

[0035] The recovered hydrocarbon light liquid supply pipe is connected to the recovered hydrocarbon light liquid storage device and the first mixer, and is a pipe through which the recovered hydrocarbon light liquid in the recovered hydrocarbon light liquid storage device is delivered to the first mixer.

[0036] The recovered hydrocarbon light liquid supply pipe is provided with a recovered hydrocarbon light liquid delivery device for delivering the recovered hydrocarbon light liquid from the recovered hydrocarbon light liquid storage device to the first mixer. The recovered hydrocarbon light liquid delivery device is not particularly limited, and examples thereof include a liquid delivery pump, a diaphragm pump, and a gear pump.

[0037] The first crude oil separation pipe branches off from the process line for crude oil (C) and is connected to the first mixing device, and is a pipe through which crude oil (C) in the process line for crude oil (C) is delivered to the first mixing device.

[0038] The first crude oil separation pipe is provided with a first flow rate control device for sending the crude oil (C) in the process line for the crude oil (C) to the first mixer. The first flow rate control device is not particularly limited, and examples thereof include a liquid feed pump, a diaphragm pump, and a gear pump.

[0039] The second mixing device is a device for mixing the first mixed liquid with the crude oil (C) fractionated from the process line for the crude oil (C) or the first crude oil fractionation pipe to obtain a treated oil for crude oil blending. The second mixing device is not particularly limited, and examples thereof include a line mixer.

[0040] The first mixed liquid delivery pipe is connected to the first mixing device and the second mixing device, and is a pipe through which the first mixed liquid is delivered to the second mixing device.

[0041] The first mixture delivery pipe is provided with a first heating device for heating the first mixture to a temperature equal to or higher than the precipitation point of the first mixture. The first heating device is not particularly limited, and examples thereof include a heat exchanger and a steam trace. In the present invention, the precipitation point is measured using a differential scanning calorimeter specified in JIS K-0129, and the temperature at which heat generation occurs during cooling is defined as the precipitation point.

[0042] The second crude oil collection pipe branches off from the process line for crude oil (C) or the first crude oil collection pipe and is connected to the second mixing device, and is a pipe through which crude oil (C) in the process line for crude oil (C) or the first crude oil collection pipe is delivered to the second mixing device.

[0043] The second crude oil collection pipe is provided with a second flow rate control device for sending the crude oil (C) in the process line for the crude oil (C) or in the first crude oil collection pipe to the second mixer. The second flow rate control device is not particularly limited, and examples thereof include a liquid feed pump, a diaphragm pump, and a gear pump.

[0044] The second crude oil fractionating pipe may be provided with a heating device for heating the crude oil (C). The heating device provided in the second crude oil fractionating pipe is not particularly limited, and examples include a heat exchanger, a steam tracer, and the like. When the apparatus for producing treated oil for crude oil blending of the present invention is used in winter or in low-temperature regions, the temperature of the crude oil (C) flowing into the second mixing apparatus may become too low. If the temperature of the crude oil (C) flowing into the second mixing apparatus becomes too low, wax may precipitate after mixing with the first mixed liquid. In such cases, by providing the second crude oil fractionating pipe with a heating device for heating the crude oil (C) and heating the crude oil (C) before mixing it with the first mixed liquid, wax precipitation after mixing the first mixed liquid with the crude oil (C) can be prevented.

[0045] The manufacturing apparatus for crude oil blending processed oil of the present invention is installed in the process line of crude oil (C) and can have a third mixing apparatus for mixing the crude oil blending processed oil obtained in the second mixing apparatus with crude oil (C) in the process line of crude oil (C), and a crude oil blending processed oil delivery pipe connecting the second mixing apparatus and the third mixing apparatus.

[0046] The third mixing device is a device for mixing the treated oil for crude oil blending with the crude oil (C) in the process line of the crude oil (C). The third mixing device is not particularly limited, and may be a line mixer.

[0047] The crude oil blending treatment oil delivery pipe is connected to the second blending device and the third blending device, and is a pipe through which the crude oil blending treatment oil is delivered to the third blending device.

[0048] In the manufacturing apparatus for crude oil blending processed oil of the present invention, a fourth mixing device can be provided midway along the path from the second mixing device to the third mixing device for blending crude oil (C) with the crude oil blending processed oil obtained in the second mixing device. That is, the manufacturing apparatus for processed oil for crude oil blending of the present invention can have, instead of the above-mentioned processed oil delivery pipe for crude oil blending, a fourth mixing device between the second mixing device and the third mixing device, which mixes the second mixed liquid obtained by the second mixing device with the crude oil (C) fractionated from the process line for crude oil (C), the first crude oil fractionation pipe or the second crude oil fractionation pipe; a second mixed liquid delivery pipe connecting the second mixing device and the fourth mixing device; a second heating device provided in the second mixed liquid delivery pipe for heating the second mixed liquid obtained by the second mixing device to a temperature equal to or higher than the crystallization point of the second mixed liquid; a third crude oil fractionation pipe branching from the process line for crude oil (C), the first crude oil fractionation pipe or the second crude oil fractionation pipe and connected to the fourth mixing device; a third flow rate control device provided in the third crude oil fractionation pipe; and a second processed oil delivery pipe for crude oil blending which connects the fourth mixing device and the third mixing device.

[0049] The fourth mixing device is a device for mixing the second mixed liquid obtained by the second mixing device with the crude oil (C) fractionated from the crude oil (C) process line, the first crude oil fractionation pipe, or the second crude oil fractionation pipe, to obtain a second crude oil blending treated oil. The fourth mixing device is not particularly limited, and examples thereof include a line mixer.

[0050] The second mixed liquid delivery pipe is connected to the second mixer and the fourth mixer, and is a pipe through which the second mixed liquid is delivered to the fourth mixer.

[0051] The second mixture delivery pipe is provided with a second heating device for heating the second mixture to a temperature equal to or higher than the precipitation point of the second mixture. The second heating device is not particularly limited, and examples thereof include a heat exchanger and a steam tracer.

[0052] The third crude oil fractionation pipe branches off from the process line for crude oil (C), the first crude oil fractionation pipe, or the second crude oil fractionation pipe, and is connected to the fourth mixing device. The third crude oil fractionation pipe is a pipe through which crude oil (C) in the process line for crude oil (C), the first crude oil fractionation pipe, or the second crude oil fractionation pipe is delivered to the fourth mixing device.

[0053] The third crude oil collection pipe is provided with a third flow rate control device for sending the crude oil (C) in the process line for the crude oil (C), in the first crude oil collection pipe, or in the second crude oil collection pipe to the fourth mixer. The third flow rate control device is not particularly limited, and examples thereof include a liquid feed pump, a diaphragm pump, and a gear pump.

[0054] The third crude oil fractionating pipe may be provided with a heating device for heating the crude oil (C). The heating device provided in the third crude oil fractionating pipe is not particularly limited, and examples include a heat exchanger, a steam tracer, and the like. When the apparatus for producing treated oil for crude oil blending of the present invention is used in winter or in low-temperature regions, the temperature of the crude oil (C) flowing into the fourth mixing device may become too low. If the temperature of the crude oil (C) flowing into the third mixing device becomes too low, wax may precipitate after mixing with the second mixed liquid. In such cases, by providing the third crude oil fractionating pipe with a heating device for heating the crude oil (C) and heating the crude oil (C) before mixing it with the second mixed liquid, wax precipitation after mixing of the second mixed liquid with the crude oil (C) can be prevented.

[0055] The third mixed liquid delivery pipe is connected to the fourth mixer and the third mixer, and is a pipe through which the second crude oil mixed treated oil is delivered to the third mixer.

[0056] In the manufacturing apparatus for crude oil blending treated oil of the present invention, flow control devices such as liquid transfer pumps, diaphragm pumps, and gear pumps, flow switching valves, degassing devices, etc. may also be installed at desired locations as necessary.

[0057] In the manufacturing apparatus for processed oil for crude oil blending of the present invention, the recovered hydrocarbon light liquid is not mixed with crude oil (C) in the process line for crude oil (C) while the liquid temperature is high, but rather crude oil (C) having a low liquid temperature is mixed with a first mixed liquid heated to a temperature above the deposition point, and the lowered temperature processed oil for crude oil blending is mixed with crude oil (C) in the process line for crude oil (C), so that it is expected to have the effect of preventing local heating of part of the crude oil in the process line for crude oil (C).

[0058] Furthermore, if the crude oil (C) is mixed with the recovered hydrocarbon light liquid in a single stage, the low-temperature crude oil (C) will cause sludge-causing precipitates to precipitate when the temperature of the mixed liquid drops, and if such a mixed liquid is mixed with crude oil (C), sludge will be more likely to occur in the mixed crude oil (C). Therefore, in the apparatus for producing treated oil for crude oil blending of the present invention, the crude oil (C) is mixed with the recovered hydrocarbon light liquid in two stages, i.e., after mixing the crude oil (C) in the first stage, the mixed liquid obtained in the first stage is heated to a temperature above the precipitation point to dissolve the precipitates that cause sludge to occur in the first mixed liquid, and then the crude oil (C) is mixed in the second stage, so that precipitates that cause sludge to occur are less likely to occur even when the mixture is at a low temperature. Therefore, in the manufacturing apparatus for crude oil blending processed oil of the present invention, even when blended with crude oil (C) in the process line of crude oil (C), it is possible to obtain a crude oil blending processed oil that is less likely to generate sludge in the crude oil (C) and that can prevent the vaporization of light components due to local heating of part of the crude oil.

[0059] The method for producing processed oil for blending with crude oil of the present invention comprises: a recovered hydrocarbon light liquid storage step of storing recovered hydrocarbon light liquid, recovered by centrifuging crude oil sludge (A) or a mixture of crude oil sludge (A) and crude oil (B), in a state where the recovered hydrocarbon light liquid is heated to a temperature at or above which the fluidity of the recovered hydrocarbon light liquid is maintained and the recovered hydrocarbon light liquid can be fed by a liquid feed pump; a first mixing step of mixing the recovered hydrocarbon light liquid with crude oil (C) separated from a process line for crude oil (C) to obtain a first mixed liquid; a first heating step of heating the first mixed liquid to a temperature at or above the precipitation point of the first mixed liquid; and a second mixing step of mixing the first mixed liquid heated in the first heating step with crude oil (C) separated from the process line for crude oil (C) to obtain processed oil for blending with crude oil.

[0060] The recovered hydrocarbon light liquid storage step is a step of storing the recovered hydrocarbon light liquid recovered by centrifuging the crude oil sludge (A) or a mixture of the crude oil sludge (A) and crude oil (B) in a state where the recovered hydrocarbon light liquid is heated to a temperature that maintains the fluidity of the recovered hydrocarbon light liquid and is at least at a temperature at which the recovered hydrocarbon light liquid can be transported by a liquid transport pump.

[0061] The crude oil sludge (A) and crude oil (B) involved in the recovered hydrocarbon light liquid storage step are the same as the crude oil sludge (A) and crude oil (B) involved in the production apparatus for treated oil for crude oil blending of the present invention.

[0062] The recovered hydrocarbon light liquid in the recovered hydrocarbon light liquid storage step is obtained by heating and stirring crude oil sludge (A) or mixing crude oil sludge (A) and crude oil (B), heating and stirring the resulting mixture, and then centrifuging the crude oil sludge (A) or the mixture of crude oil sludge (A) and crude oil (B) in a heated state to separate the light fraction. When heated, the recovered hydrocarbon light liquid contains dissolved deposit-causing substances that are the source of deposits that cause sludge to form when mixed with crude oil, and when the temperature drops, the deposits that cause sludge to form when mixed with crude oil are precipitated.

[0063] Examples of a method for obtaining a recovered hydrocarbon light liquid include a crude oil sludge heating treatment step (1) in which crude oil sludge (A) and crude oil (B) are mixed so that the ratio of the crude oil sludge (A) to the total of the crude oil sludge (A) and crude oil (B) is 20% by mass or more, and then the mixture of crude oil sludge (A) and crude oil (B) is heated and stirred at 40 to 200°C to obtain a heated and stirred product of the crude oil sludge (A) and crude oil (B); and a centrifugation step (1) in which the heated and stirred product is centrifuged at 40 to 200°C to separate the light liquid and heavy components to obtain a recovered hydrocarbon light liquid.

[0064] The crude oil sludge heat treatment step (1) is a step of mixing crude oil sludge (A) with crude oil (B), and then heating and stirring the mixture of crude oil sludge (A) and crude oil (B) at 40 to 200°C to obtain a heated and stirred product of crude oil sludge (A) and crude oil (B).

[0065] In the crude oil sludge heat treatment step (1), first, crude oil sludge (A) and crude oil (B) are mixed so that the ratio of crude oil sludge (A) to the total of crude oil sludge (A) and crude oil (B) is 20% by mass or more, preferably 20 to 99% by mass, more preferably 40 to 98% by mass, and more preferably 60 to 95% by mass. If the ratio of crude oil sludge (A) to the total of crude oil sludge (A) and crude oil (B) is less than the above range, the processing amount in the centrifugation step (1) increases, resulting in a decrease in economic efficiency, and if it exceeds the above range, the recovery of oil from crude oil sludge (A) becomes insufficient.

[0066] It should be noted that when crude oil sludge (A) is removed from a crude oil tank by pushing the crude oil sludge (A) out of the crude oil tank with crude oil (for example, COW washing), the crude oil used to remove the crude oil sludge (A) is included in crude oil (B) to calculate the ratio of crude oil sludge (A) to the total of crude oil sludge (A) and crude oil (B). Therefore, in this case, the crude oil sludge (A) is removed from the crude oil tank using an amount of crude oil such that the ratio of the crude oil sludge (A) to the total of the crude oil sludge (A) deposited at the bottom of the crude oil tank and the crude oil used to remove the crude oil sludge (A) is a predetermined mixing ratio, that is, the ratio of the crude oil sludge (A) to the total of the crude oil sludge (A) and the crude oil (B) is 20 to 99% by mass, preferably 40 to 98% by mass, and more preferably 60 to 95% by mass, and the removed mixture of crude oil sludge (A) and crude oil may be used as is as a mixture of crude oil sludge (A) and crude oil (B) to be heated and stirred. Alternatively, crude oil sludge (A) deposited at the bottom of a crude oil tank may be removed from the crude oil tank using a small amount of crude oil, and the removed mixture of crude oil sludge (A) and crude oil may be further mixed with the same type of crude oil as that used to remove the crude oil sludge (A) or a different type of crude oil to achieve a predetermined mixing ratio, i.e., the ratio of crude oil sludge (A) to the total of crude oil sludge (A) and crude oil (B) is 20 to 95% by mass, preferably 40 to 90% by mass, more preferably 60 to 90% by mass, and the resulting mixture may be used as the mixture of crude oil sludge (A) and crude oil (B) to be heated and stirred.

[0067] In the crude oil sludge heat treatment step (1), the mixture of crude oil sludge (A) and crude oil (B) is then heated and stirred at 40 to 200°C, preferably 50 to 150°C, and more preferably 60 to 100°C, to obtain a heated and stirred product of crude oil sludge (A) and crude oil (B). If the heating and stirring temperature is below the above range, the recovery of oil from the crude oil sludge (A) will be insufficient, and if it exceeds the above range, disadvantages will arise due to the loss of light fractions. The method for heating and stirring the mixture of crude oil sludge (A) and crude oil (B) is not particularly limited, and examples include a method in which the mixture of crude oil sludge (A) and crude oil (B) is heated and stirred in a tank that stores crude oil sludge (A) removed from a crude oil tank. The heating and stirring time is not particularly limited and is selected depending on the stirring conditions to achieve a uniform mixture.

[0068] The oil content in the crude oil sludge (A) is not particularly limited, but is usually 30 to 80 mass %. The oil in the crude oil sludge (A) is dissolved in the crude oil (B) by heating and stirring a mixture of the crude oil sludge (A) and crude oil (B) at 40 to 200°C, preferably 50 to 150°C, and more preferably 60 to 100°C in the crude oil sludge heat treatment step (1).

[0069] The centrifugal separation step (1) is a step in which the heated and stirred crude oil sludge (A) and crude oil (B) obtained by the crude oil sludge heat treatment step (1) are centrifuged at 40 to 200°C to separate the recovered hydrocarbon light liquid from the heavy fraction, thereby obtaining the recovered hydrocarbon light liquid, which is the light fraction.

[0070] In the centrifugation step (1), the temperature at which the heated and stirred product of the crude oil sludge (A) and crude oil (B) is centrifuged is 40 to 200°C, preferably 50 to 150°C, and more preferably 60 to 100°C. If the centrifugation temperature is below the above range, a portion of the heated and stirred product of the crude oil sludge (A) and crude oil (B) may solidify during centrifugation, or the fluidity of the heated and stirred product may be significantly reduced, making centrifugation impossible. If the centrifugation temperature exceeds the above range, disadvantages arise due to the loss of light fractions. Furthermore, the temperature at which the heated and stirred product of the crude oil sludge (A) and crude oil (B) is centrifuged in the centrifugation step (1) is preferably the same as or higher than the heating and stirring temperature of the mixture of crude oil sludge (A) and crude oil (B) in the crude oil sludge heat treatment step (1).

[0071] The heated and stirred crude oil sludge (A) and crude oil (B) obtained by the crude oil sludge heat treatment step (1) is a mixture of light liquid with a low specific gravity and heavy fractions with a higher specific gravity than the light liquid. In the centrifugation step (1), the light liquid and heavy fractions are separated based on the difference in specific gravity. The light liquid is a liquid obtained by dissolving the oil in the crude oil sludge (A) in the crude oil (B) in the crude oil sludge heat treatment step (1). In other words, the light liquid is basically composed of the crude oil (B) and the oil in the crude oil sludge (A) dissolved in the crude oil (B). The heavy fractions are components in the crude oil sludge (A) that did not dissolve in the crude oil (B) in the crude oil sludge heat treatment step (1), and are mainly asphaltene, water, iron, sand, and oil that is difficult to separate because it is incorporated into these components.

[0072] In the centrifugation step (1), the centrifuge used to centrifuge the heated and stirred product is not particularly limited, and any centrifuge may be used as long as it can continuously separate the light liquid and the heavy liquid based on the difference in specific gravity while maintaining the centrifugation temperature. Examples include a decanter centrifuge, a disc separator centrifuge, or a centrifuge combining these.

[0073] The physical properties of the light liquid obtained by carrying out the centrifugation step (1) are not particularly limited, but the density is preferably 0.80 to 0.95 g / cm ３, more preferably 0.80 to 0.88 g / cm ３ The melting point is preferably 40 to 150°C, more preferably 40 to 110°C, and even more preferably 40 to 90°C, the freezing point is preferably 30 to 140°C, more preferably 30 to 100°C, and even more preferably 30 to 80°C, and the oil content is 60% by mass or more.

[0074] Another method for obtaining a recovered hydrocarbon light liquid includes a crude oil sludge heat treatment step (2) in which crude oil sludge (A) is heated at 40 to 200°C to obtain a heat-treated crude oil sludge (A), and a centrifugation step (2) in which the heat-treated crude oil sludge (A) is centrifuged at 40 to 200°C to separate the light liquid from the heavy components and obtain a recovered hydrocarbon light liquid.

[0075] The crude oil sludge heat treatment step (2) is a step in which crude oil sludge (A) is heated at 40 to 200° C. to obtain a heat-treated crude oil sludge (A).

[0076] The crude oil sludge (A) in the crude oil sludge heat treatment step (2) is the same as the crude oil sludge (A) in the crude oil sludge heat treatment step (1).

[0077] In the crude oil sludge heat treatment step (2), crude oil sludge (A) is heated at 40 to 200°C, preferably 50 to 150°C, and more preferably 60 to 100°C, to obtain a heat-treated crude oil sludge (A). If the heating temperature is below the above range, the recovery of oil from crude oil sludge (A) will be insufficient, and if it exceeds the above range, the heating cost will be high and it will be uneconomical. The method for heating crude oil sludge (A) is not particularly limited, and examples include a method in which crude oil sludge (A) is heated in a tank that stores crude oil sludge (A) removed from a crude oil tank.

[0078] The centrifugal separation step (2) is a step in which the heat-treated crude oil sludge (A) obtained by carrying out the heat treatment step (2) of the crude oil sludge is centrifuged at 40 to 200°C to separate the recovered hydrocarbon light liquid from the heavy fraction, thereby obtaining the recovered hydrocarbon light liquid as the light fraction.

[0079] In the centrifugation step (2), the temperature at which the heat-treated crude oil sludge (A) is centrifuged is 40 to 200°C, preferably 50 to 150°C, and more preferably 60 to 100°C. If the centrifugation temperature is below the above range, a portion of the heat-treated crude oil sludge (A) will solidify during centrifugation or the fluidity of the heat-treated product will be significantly reduced, making centrifugation impossible. If the centrifugation temperature exceeds the above range, the heating costs will increase and the process will be uneconomical. Furthermore, it is preferable that the temperature at which the heat-treated crude oil sludge (A) is centrifuged in the centrifugation step (2) be the same as or higher than the heating temperature of the crude oil sludge (A) in the crude oil sludge heat treatment step (2).

[0080] The heat-treated crude oil sludge (A) obtained by carrying out the heat treatment step (2) of crude oil sludge is a mixture of light liquids with low specific gravity and heavy fractions with higher specific gravity than the light liquids, and in the centrifugation step (2), the light liquids and heavy fractions are separated based on the difference in specific gravity. The light liquids are the oil components in the crude oil sludge (A). In other words, the light liquids are basically composed of the oil components in the crude oil sludge (A). The heavy fractions are components in the crude oil sludge (A) that have a higher specific gravity than the oil components due to heating in the heat treatment step (2) of the crude oil sludge, and are mainly asphaltene, water, iron, sand, and oil components that are difficult to separate because they are incorporated into these components.

[0081] In the centrifugation step (2), the centrifuge used for centrifuging the heat-treated product is not particularly limited, and any centrifuge may be used as long as it can continuously separate the light liquid and the heavy liquid based on the difference in specific gravity while maintaining the centrifugation temperature. Examples of such a centrifuge include a decanter centrifuge, a disc separator centrifuge, and a centrifuge combining these.

[0082] The physical properties of the light liquid obtained by carrying out the centrifugation step (2) are not particularly limited, but the density is preferably 0.80 to 0.95 g / cm ３ , more preferably 0.80 to 0.88 g / cm ３The melting point is preferably 40 to 150°C, more preferably 40 to 110°C, and even more preferably 40 to 90°C, the freezing point is preferably 30 to 140°C, more preferably 30 to 100°C, and even more preferably 30 to 80°C, and the oil content is 60% by mass or more.

[0083] When heated, the recovered hydrocarbon light liquid contains dissolved deposit-causing substances that are the source of deposits that cause sludge when mixed with crude oil, and when the temperature drops, the liquid precipitates the deposits that cause sludge when mixed with crude oil. The main component of these deposits that cause sludge is wax. The content of wax in the recovered hydrocarbon light liquid is not particularly limited, but is preferably 0.1 to 10.0 mass%, more preferably 0.1 to 8.0 mass%.

[0084] In the recovered hydrocarbon light liquid storage step, the recovered hydrocarbon light liquid is stored in a state where it is heated to a temperature equal to or higher than "the temperature at which the recovered hydrocarbon light liquid can be maintained in fluidity and can be sent by a liquid sending pump" so that the recovered hydrocarbon light liquid maintains its fluidity. The heating temperature of the recovered hydrocarbon light liquid in the recovered hydrocarbon light liquid storage step is a temperature equal to or higher than "the temperature at which the recovered hydrocarbon light liquid can be maintained in fluidity and can be sent by a liquid sending pump", preferably a temperature at which the kinematic viscosity is 15 mm ２ / s, more preferably 60°C or higher, and more preferably 70°C or higher. By setting the heating temperature of the recovered hydrocarbon light liquid in the recovered hydrocarbon light liquid storage step within the above range, excessive precipitation of precipitates from the recovered hydrocarbon light liquid is suppressed, the fluidity of the recovered hydrocarbon light liquid is ensured, and it is easy to mix it with the crude oil (C). Furthermore, the heating temperature of the recovered hydrocarbon light liquid in the recovered hydrocarbon light liquid storage step is preferably 80°C or lower, since it is easy to suppress localized heating when the recovered hydrocarbon light liquid is mixed with the crude oil (C).

[0085] The first mixing step is a step of mixing the recovered hydrocarbon light liquid heated in the recovered hydrocarbon light liquid storage step with crude oil (C) to obtain a first mixed liquid.

[0086] The crude oil (C) involved in the first blending step is crude oil in a process line for transferring crude oil (C) to a crude oil tank, and is crude oil to be transferred to the crude oil tank. The crude oil (C) involved in the first blending step is the same as the crude oil (C) involved in the production apparatus for crude oil blending of the present invention.

[0087] The temperature of the crude oil (C) to be mixed with the recovered hydrocarbon light liquid is usually 30 to 50°C.

[0088] The mixing ratio (volume ratio) of the recovered hydrocarbon light liquid to the crude oil (C) in the first mixing step is appropriately selected depending on the properties of the recovered hydrocarbon light liquid and the crude oil (C). For example, the mixing ratio of the crude oil (C) to the recovered hydrocarbon light liquid (crude oil (C) / recovered hydrocarbon light liquid) is 1.0 to 4.0, preferably 1.0 to 3.5, in volume ratio. When the mixing ratio of the crude oil (C) to the recovered hydrocarbon light liquid (crude oil (C) / recovered hydrocarbon light liquid) is within the above range, the precipitate is likely to be sufficiently dissolved in the first mixed liquid in the first heating step. On the other hand, if the mixing ratio of the crude oil (C) to the recovered hydrocarbon light liquid (crude oil (C) / recovered hydrocarbon light liquid) is below the above range, the precipitate may not be sufficiently dissolved. On the other hand, if the mixing ratio exceeds the above range, the amount of processing in the first heating step and the second mixing step may be too large, resulting in a decrease in production efficiency.

[0089] In the first mixing step, the method for mixing the recovered hydrocarbon light liquid with the crude oil (C) is not particularly limited, and examples thereof include a method in which mixing is performed using a line mixer.

[0090] The first mixed liquid is obtained by carrying out the first mixing step. The first mixed liquid is obtained by mixing low-temperature crude oil (C) with recovered hydrocarbon light liquid that has a high content of deposit-causing substances that are the source of deposits that cause sludge when mixed with crude oil, so that the first mixed liquid may contain deposits that cause sludge when mixed with crude oil.

[0091] The first heating step is a step of heating the first mixture to a temperature equal to or higher than the precipitation point of the first mixture. The heating temperature of the first mixture in the first heating step is equal to or higher than the precipitation point of the first mixture, preferably 60°C or higher, more preferably 70°C or higher. When the heating temperature of the first mixture in the first heating step is within the above range, it is possible to dissolve precipitates in the first mixture, and therefore sludge is less likely to occur even when the treated oil for crude oil blending is mixed with crude oil (C). Furthermore, the heating temperature of the first mixture in the first heating step is preferably 80°C or lower, since this makes it easy to suppress localized heating when the first mixture is mixed with crude oil (C).

[0092] By carrying out the first heating step, the precipitate deposited in the first mixed liquid can be dissolved in the first mixed liquid. At this time, since the first mixed liquid is a mixture of crude oil (C), light components having boiling points at atmospheric pressure lower than the heating temperature are present in the first mixed liquid. However, since the pipe through which the first mixed liquid is delivered is sealed, the next step can be carried out even if a small amount of gas is generated, or, since the pipe through which the first mixed liquid is delivered is sealed and pressurized, the generated gas is absorbed into the first mixed liquid.

[0093] The second mixing step is a step of mixing the first mixed liquid heated in the first step with crude oil (C) to obtain a treated oil for crude oil mixing.

[0094] The crude oil (C) involved in the second blending step is crude oil in a process line for transferring crude oil (C) to a crude oil tank, and is the crude oil to be transferred to the crude oil tank. The crude oil (C) involved in the second blending step is the same as the crude oil (C) involved in the production apparatus for crude oil blending of the present invention.

[0095] The temperature of the crude oil (C) to be mixed with the first mixture is usually 30 to 50°C, preferably 40 to 50°C. When the method for producing a processed oil for crude oil blending of the present invention is carried out in winter or in a region with low temperatures, the temperature of the crude oil (C) to be mixed with the first mixture may become too low, for example, below 30°C. If the temperature of the crude oil (C) to be mixed with the first mixture becomes too low, wax may precipitate after mixing with the first mixture. In such cases, by heating the crude oil (C) before mixing with the first mixture, wax can be prevented from precipitating in the processed oil for crude oil blending after mixing the first mixture with the crude oil (C).

[0096] The mixing ratio (volume ratio) of the first mixed liquid to the crude oil (C) in the second mixing step is appropriately selected depending on the properties of the first mixed liquid and the crude oil (C), and for example, the mixing ratio of the crude oil (C) to the first mixed liquid (crude oil (C) / first mixed liquid) is 1.0 to 3.0, preferably 1.0 to 2.5, in volume ratio. When the mixing ratio of the crude oil (C) to the first mixed liquid (crude oil (C) / first mixed liquid) is within the above range, it is possible to obtain a treated oil for crude oil blending that can suppress an increase in the amount of sludge generated when the treated oil for crude oil blending is finally mixed with crude oil, and that can also suppress the vaporization of light components due to localized heating. On the other hand, if the mixing ratio of crude oil (C) to the first mixed liquid (crude oil (C) / first mixed liquid) is less than the above range, there is a risk that the amount of sludge generated will increase when the crude oil is finally mixed with the treated oil for crude oil blending, or that vaporization of light components will occur due to localized heating when the treated oil for crude oil blending is mixed with the crude oil.Furthermore, if the mixing ratio exceeds the above range, there is a risk that the processing amount in the second mixing step will be too large, resulting in low production efficiency.

[0097] The amount of crude oil (C) mixed in the second mixing step is preferably selected so that the total amount of crude oil (C) mixed in the first mixing step and the second mixing step is an amount that will not cause deposition of a precipitate that will later cause sludge generation when the high-temperature first mixed liquid is mixed with the low-temperature crude oil (C) and the liquid temperature is lowered.

[0098] In the second mixing step, the method for mixing the first mixed liquid with the crude oil (C) is not particularly limited, and examples thereof include a method in which mixing is performed using a line mixer.

[0099] The second mixing step produces a processed oil for crude oil blending. The first mixed liquid before blending in the second mixing step is heated to a temperature equal to or higher than the precipitation point of the first mixed liquid by the heating step, dissolving precipitates that can cause sludge formation. Furthermore, the total amount of crude oil (C) in the first and second mixing steps is adjusted to an amount that prevents sludge formation from forming even when the liquid temperature drops. Therefore, even when the first mixed liquid is mixed with crude oil (C) in the second mixing step and the liquid temperature drops, precipitates that can cause sludge formation do not precipitate. Furthermore, the temperature of the processed oil for crude oil blending is low enough to prevent localized heating of parts of the crude oil when mixed with crude oil (C) in the process line for crude oil (C). The temperature of the processed oil for crude oil blending is preferably 40 to 60°C, more preferably 50 to 60°C.

[0100] The method for producing a processed oil for crude oil blending of the present invention can include a third blending step in which the processed oil for crude oil blending obtained by carrying out the second blending step is blended with crude oil (C) in the process line for crude oil (C).

[0101] In the third mixing step, the method for mixing the treated oil for crude oil blending with the crude oil (C) is not particularly limited, and examples thereof include a method of mixing using a line mixer.

[0102] The method for producing a processed oil for blending with crude oil of the present invention can include: a second heating step, performed after the second blending step and before the third blending step, of heating a second mixed liquid (a mixed liquid of the first mixed liquid and crude oil (C)) obtained by the second blending step to a temperature equal to or higher than the crystallization point of the second mixed liquid; and a fourth blending step of mixing the heated second mixed liquid obtained by the second heating step with crude oil (C) to obtain a second processed oil for blending with crude oil. In this embodiment, the second processed oil for blending with crude oil obtained by the fourth blending step is used as the processed oil for blending with crude oil in the third blending step.

[0103] The second heating step is a step of heating the second mixture to a temperature equal to or higher than the precipitation point of the second mixture. The heating temperature of the second mixture in the second heating step is a temperature equal to or higher than the precipitation point of the second mixture, preferably 60°C or higher, more preferably 70°C or higher. When the heating temperature of the second mixture in the second heating step is within the above range, it is possible to dissolve precipitates in the second mixture, and therefore sludge is less likely to occur even when the treated oil for crude oil blending is mixed with crude oil (C). Furthermore, the heating temperature of the second mixture in the second heating step is preferably 80°C or lower, since this makes it easy to suppress localized heating when the second mixture is mixed with crude oil (C).

[0104] By carrying out the second heating step, the precipitate deposited in the second mixed liquid can be dissolved in the second mixed liquid. At this time, since the second mixed liquid is a mixture of crude oil (C), light components having boiling points at atmospheric pressure lower than the heating temperature are present in the second mixed liquid. However, since the pipe through which the second mixed liquid is delivered is sealed, the next step can be carried out even if a small amount of gas is generated, or, since the pipe through which the second mixed liquid is delivered is sealed and pressurized, the generated gas is absorbed into the second mixed liquid.

[0105] The fourth mixing step is a step of mixing the second mixed liquid heated in the second heating step with crude oil (C) to obtain a second treated oil for crude oil mixing.

[0106] The crude oil (C) involved in the fourth blending step is crude oil in a process line for transferring crude oil (C) to a crude oil tank, and is crude oil to be transferred to the crude oil tank. The crude oil (C) involved in the fourth blending step is the same as the crude oil (C) involved in the manufacturing apparatus for crude oil blending of the present invention.

[0107] The temperature of the crude oil (C) to be mixed with the second mixture is usually 30 to 50°C, preferably 40 to 50°C. When the method for producing a processed oil for crude oil blending of the present invention is carried out in winter or in a region with low temperatures, the temperature of the crude oil (C) to be mixed with the second mixture may become too low, for example, below 30°C. If the temperature of the crude oil (C) to be mixed with the second mixture becomes too low, wax may precipitate after mixing with the second mixture. In such cases, by heating the crude oil (C) before mixing with the second mixture, wax can be prevented from precipitating in the second processed oil for crude oil blending after mixing the second mixture with the crude oil (C).

[0108] The mixing ratio (volume ratio) of the second mixed liquid to the crude oil (C) in the fourth mixing step is appropriately selected depending on the properties of the first mixed liquid and the crude oil (C), and for example, the mixing ratio of the crude oil (C) to the second mixed liquid (crude oil (C) / second mixed liquid) is 1.0 to 3.0, preferably 1.0 to 2.0, in volume ratio. When the mixing ratio of the crude oil (C) to the second mixed liquid (crude oil (C) / second mixed liquid) is within the above range, it is possible to obtain a treated oil for crude oil blending that can suppress an increase in the amount of sludge generated when the treated oil for crude oil blending is finally mixed with crude oil, and that can also suppress the vaporization of light components due to localized heating. On the other hand, if the mixing ratio of crude oil (C) to the second mixed liquid (crude oil (C) / second mixed liquid) is less than the above range, there is a risk that the amount of sludge generated will increase when the crude oil is finally mixed with the treated oil for crude oil blending, or that vaporization of light components will occur due to localized heating when the treated oil for crude oil blending is mixed with the crude oil.Furthermore, if the mixing ratio exceeds the above range, there is a risk that the processing amount in the fourth mixing step will be too large, resulting in low production efficiency.

[0109] The amount of crude oil (C) mixed in the fourth mixing step is preferably selected so that the total amount of crude oil (C) mixed in the first mixing step, the second mixing step, and the fourth mixing step is an amount that makes it difficult for precipitates that cause sludge to precipitate when the high-temperature second mixed liquid is mixed with the low-temperature crude oil (C) and the liquid temperature drops.

[0110] In the fourth mixing step, the method for mixing the second mixed liquid with the crude oil (C) is not particularly limited, and examples thereof include a method of mixing using a line mixer.

[0111] By carrying out the fourth mixing step, a processed oil for second crude oil blending is obtained. The second mixed liquid before mixing in the fourth mixing step has dissolved precipitates that cause sludge generation, and the total amount of crude oil (C) in the first, second, and fourth mixing steps is adjusted to an amount that does not cause sludge generation precipitates even when the liquid temperature drops. Therefore, even when the second mixed liquid is mixed with crude oil (C) in the fourth mixing step and the liquid temperature drops, precipitates that cause sludge generation do not precipitate. Furthermore, the temperature of the processed oil for crude oil blending is low enough to prevent localized heating of parts of the crude oil when mixed with crude oil (C) in the process line for crude oil (C). The temperature of the processed oil for second crude oil blending is preferably 40 to 60°C, more preferably 50 to 60°C.

[0112] In the method for producing processed oil for crude oil blending of the present invention, instead of mixing the recovered hydrocarbon light liquid at a high liquid temperature with crude oil (C) in the process line for crude oil (C), a first mixed liquid heated to a temperature above the temperature at which precipitates dissolve is mixed with crude oil (C) at a low liquid temperature, and the lowered temperature processed oil for crude oil blending is mixed with crude oil (C) in the process line for crude oil (C), thereby making it possible to prevent local heating of a portion of the crude oil being blended in the process line for crude oil (C).

[0113] Furthermore, if the crude oil (C) is mixed with the recovered hydrocarbon light liquid in only one stage, the low-temperature crude oil (C) will cause sludge-causing precipitates to precipitate when the temperature of the mixed liquid drops, and if such a mixed liquid is mixed with the crude oil (C), sludge will be more likely to occur in the mixed crude oil (C). Therefore, in the method for producing a processed oil for crude oil blending of the present invention, the crude oil (C) is mixed with the recovered hydrocarbon light liquid in two stages (or three stages), i.e., after mixing the crude oil (C) in the first stage, the first mixed liquid is heated to a temperature above the precipitate point to dissolve the precipitates that precipitate in the first stage of mixing in the first mixed liquid, and then the total amount of crude oil (C) to be mixed in the second stage (or the second and third stages) is adjusted to an amount that will not cause sludge-causing precipitates to precipitate even when the mixture is cooled, and then the crude oil (C) is mixed, so that sludge-causing precipitates are less likely to precipitate even when the temperature of the processed oil for crude oil blending is lowered. Therefore, in the method for producing a processed oil for crude oil blending of the present invention, even when it is blended with crude oil (C) in the process line of crude oil (C), it is possible to obtain a processed oil for crude oil blending that is unlikely to increase the amount of sludge generated due to the recovered hydrocarbon light liquid and that is at a temperature low enough to prevent local heating of part of the crude oil.

[0114] The processed oil for blending with crude oil of the present invention is obtained by the above-described method for producing processed oil for blending with crude oil of the present invention.

[0115] The present invention will be explained in more detail below by showing examples, but the present invention is not limited thereto.

[0116] <Crude oil sludge (A)> Crude oil sludge a recovered from a crude oil tank <Crude oil (B)> Crude oil b having the following analytical values: API 35.4°, water mud content 0 vol% <Crude oil (C)> The above crude oil b was used as crude oil (C).

[0117] <Preparation of Recovered Hydrocarbon Light Liquid> Crude oil sludge a and crude oil b were added to a stirring vessel so that the ratio of crude oil sludge a to the total was 95 mass%, and the mixture was heated and stirred at 80°C. Next, while maintaining the temperature at 80°C, the heated and stirred product was placed in a centrifuge set at 80°C and subjected to decanter centrifugation under conditions of 80°C, 3500G, and 30 to 60 seconds, resulting in separation into four layers: light liquid (69% by volume), heavy fraction (21% by volume), aqueous layer (8% by volume), and solid fraction (2% by volume). This light liquid was used in subsequent processing as recovered hydrocarbon light liquid 1. The kinematic viscosity of recovered hydrocarbon light liquid 1 at 56°C was 15 mm ２ The wax content was 4.5% by mass.

[0118] (Example 1) Recovered hydrocarbon light liquid 1 (kinematic viscosity at 100°C: 4.007 mm ２ / s) was heated to 60°C. Next, recovered hydrocarbon light liquid 1 heated to 60°C and crude oil b at 30°C were mixed in a volume ratio of 1:2 using a line mixer to obtain a first mixed liquid 1. First mixed liquid 1 was measured using a differential scanning calorimeter, and the crystallization point was found to be 70°C. Next, first mixed liquid 1 was heated to 80°C. Next, first mixed liquid 1 heated to 80°C and crude oil b at 30°C were mixed in a volume ratio of 1:1 using a line mixer to obtain a processed oil for crude oil blending 1. Next, the obtained processed oil for crude oil blending 1 was diluted with crude oil b at 30°C so that the recovered hydrocarbon light liquid 1 contained in the whole was adjusted to 5% by volume, and sample 1 was obtained.

[0119] (Comparative Example 1) Recovered hydrocarbon light liquid 1 (kinematic viscosity at 100°C: 4.007 mm ２ / s) was heated to 60°C to obtain a crude oil blending processed oil 2. Next, the crude oil blending processed oil 2 was diluted with crude oil b at 30°C so that the recovered hydrocarbon light liquid 1 contained in the whole was 5% by volume, and sample 2 was obtained.

[0120] <Evaluation> 100 mL of each of Sample 1, Sample 2, and Crude Oil b was taken and centrifuged at 600 G for 12 minutes in a centrifuge to accelerate the settling of sludge, and the amount of sediment, i.e., the amount of sludge, was measured. The results are shown in Table 1.

[0121]

[0122] (Measurement of kinematic viscosity) Measurement was carried out based on JIS K2283:2000.

[0123] (Measurement of Precipitation Point) Measurement was performed using a differential scanning calorimeter under the following measurement conditions, and the temperature at which heat generation occurred during cooling was taken as the precipitation point. <Measurement Conditions> Apparatus: DSCvesta (manufactured by Rigaku Corporation) Temperature program: Room temperature → 100°C (holding time: 10 minutes) → 30°C Temperature increase / decrease rate: 10°C / min Sample container: Aluminum container Reference: α-alumina Sample amount: 10 mg Number of measurements: 2

[0124] From Example 1, it was found that when recovered hydrocarbon light liquid is directly mixed into crude oil (Sample 2), sludge increases compared to the original crude oil to which recovered hydrocarbon light liquid has not been mixed. However, by performing the first stage of mixing, heating the mixture, and then performing the second stage of mixing, it is possible to obtain a treated oil for crude oil mixing (Sample 1) that is low enough in temperature to prevent localized heating even when mixed with crude oil, and that does not increase sludge compared to the original crude oil to which recovered hydrocarbon light liquid has not been mixed.

[0125] Example 2 Using the apparatus of Figure 1, a crude oil blending treatment was produced as follows: A recovered hydrocarbon light liquid (having a kinematic viscosity of 15 mm at 56°C) at 60°C was placed in a first blending device (line mixer). ２The crude oil was introduced and mixed in a ratio of 1 volume of the recovered hydrocarbon light liquid to 2 volumes of crude oil, yielding a first mixture. The first mixture was measured using a differential scanning calorimeter, and the resulting precipitate point was 70°C. The resulting first mixture was then heated to 80°C in a first heating device, and then 1 volume of crude oil was introduced and mixed with 1 volume of the first mixture heated at 80°C into a second mixing device (line mixer), yielding a processed oil for crude oil blending. The thus-obtained processed oil for crude oil blending and the crude oil were then introduced and mixed into a third mixing device (line mixer), yielding a crude oil containing approximately 2 volume% of recovered hydrocarbon light liquid, calculated as recovered hydrocarbon light liquid. Next, 100 mL each of the resulting crude oil containing approximately 2 volume% of recovered hydrocarbon light liquid and the original crude oil containing no recovered hydrocarbon light liquid were sampled and centrifuged at 600 G for 12 minutes in a centrifuge to accelerate sludge sedimentation, and the amount of sediment, i.e., the amount of sludge, was measured. As a result, the amount of sludge generated from crude oil containing approximately 2% by volume of recovered hydrocarbon light liquid increased by less than 1% compared to the amount of sludge generated from the original crude oil (((amount of sludge generated from crude oil containing approximately 2% by volume of recovered hydrocarbon light liquid - amount of sludge generated from original crude oil) / amount of sludge generated from original crude oil) x 100), and was at the same level. From this, it was confirmed that by using the apparatus and production method of the present invention, it is possible to suppress precipitates that occur when recovered hydrocarbon light liquid is mixed with crude oil, and to suppress re-sludge generation from the recovered hydrocarbon light liquid. Furthermore, no vaporization of light components due to local heating during mixing was observed.

[0126] REFERENCE SIGNS LIST 1 Recovered hydrocarbon light liquid storage device 2 First mixing device 3 First heating device 4 Second mixing device 5 Third mixing device 6 Crude oil tank 7 Recovered hydrocarbon light liquid delivery device 8 First flow control device 9 Second flow control device 10 Manufacturing device for processed oil for crude oil blending 11 Recovered hydrocarbon light liquid 12 First mixed liquid 13 Processed oil for crude oil blending 14 Crude oil (C) 15 Crude oil (C) blended with processed oil for crude oil blending 13 21 Recovered hydrocarbon light liquid supply pipe 22 First mixed liquid delivery pipe 23 First crude oil collection pipe 24 Processed oil delivery pipe for crude oil blending 25 Second crude oil collection pipe 26 Process line for crude oil (C)

[0127] According to the present invention, a method for treating recovered hydrocarbon light liquid obtained by centrifuging crude oil sludge can be provided in which, even when the recovered hydrocarbon light liquid is mixed with crude oil, sludge caused by the recovered hydrocarbon light liquid is unlikely to occur in the mixed crude oil, thereby making it possible to effectively utilize the oil content in crude oil sludge on an industrial scale.

Claims

1. An apparatus for producing a treated oil for crude oil blending by mixing a recovered light hydrocarbon liquid recovered from crude oil sludge by centrifugation with crude oil, comprising at least: a recovered light hydrocarbon liquid storage apparatus for storing the recovered light hydrocarbon liquid in a heated state at a temperature at which the recovered light hydrocarbon liquid can be maintained in fluidity and fed by a liquid feed pump or higher; a first mixing apparatus for mixing the recovered light hydrocarbon liquid with crude oil separated from a crude oil process line to obtain a first mixed liquid; a recovered light hydrocarbon liquid supply pipe connecting the recovered light hydrocarbon liquid storage apparatus and the first mixing apparatus; a recovered light hydrocarbon liquid delivery apparatus provided on the recovered light hydrocarbon liquid supply pipe; a first crude oil fractionation pipe branching off from the crude oil process line and connected to the first mixing apparatus; a first flow control device provided on the first crude oil fractionation pipe; and a second mixing apparatus for mixing the first mixed liquid with crude oil separated from the crude oil process line or the first crude oil fractionation pipe to obtain a treated oil for crude oil blending. a first mixed liquid delivery pipe connecting the first mixing device and the second mixing device; a first heating device provided in the first mixed liquid delivery pipe for heating the first mixed liquid to a temperature equal to or higher than the deposition point of the first mixed liquid; a second crude oil fractionation pipe branching off from the crude oil process line or the first crude oil fractionation pipe and connected to the second mixing device; and a second flow rate control device provided in the second crude oil fractionation pipe.

2. An apparatus for producing treated oil for blending with crude oil according to claim 1, characterized in that the first mixer and the second mixer are line mixers.

3. An apparatus for producing treated oil for blending with crude oil according to claim 1 or 2, further comprising a third mixing device for mixing the treated oil for blending with crude oil in the crude oil process line.

4. A method for producing a treated oil for blending with crude oil, comprising: a recovered hydrocarbon light liquid storage step of storing a recovered hydrocarbon light liquid recovered by centrifuging crude oil sludge (A) or a mixture of crude oil sludge (A) and crude oil (B) in a state in which the recovered hydrocarbon light liquid is heated to a temperature at which the fluidity of the recovered hydrocarbon light liquid is maintained and which is equal to or higher than a temperature at which the recovered hydrocarbon light liquid can be fed by a feed pump; a first mixing step of mixing the recovered hydrocarbon light liquid with crude oil (C) separated from a process line for crude oil (C) to obtain a first mixed liquid; a first heating step of heating the first mixed liquid to a temperature at which the first mixed liquid precipitates or exceeds the temperature at which the first mixed liquid precipitates; and a second mixing step of mixing the first mixed liquid heated by the first heating step with crude oil (C) separated from the process line for crude oil (C) to obtain a treated oil for blending with crude oil.

5. A method for producing a treated oil for mixing with crude oil according to claim 4 or 5, comprising carrying out a crude oil sludge heating treatment step (1) of mixing the crude oil sludge (A) and the crude oil (B) so that the ratio of the crude oil sludge (A) to the total of the crude oil sludge (A) and the crude oil (B) is 20 mass% or more, and then heating and stirring the mixture of the crude oil sludge (A) and the crude oil (B) at 40 to 200°C to obtain a heated and stirred product of the crude oil sludge (A) and the crude oil (B), and a centrifugation step (1) of centrifuging the heated and stirred product at 40 to 200°C to separate the light liquid and the heavy components to obtain the recovered hydrocarbon light liquid, thereby obtaining the recovered hydrocarbon light liquid.

6. A method for producing a treated oil for mixing with crude oil according to claim 4 or 5, characterized in that the recovered hydrocarbon light liquid is obtained by carrying out: a crude oil sludge heat treatment step (2) of heating the crude oil sludge (A) at 40 to 200°C to obtain a heat-treated crude oil sludge (A); and a centrifugation step (2) of centrifuging the heat-treated product at 40 to 200°C to separate it into light liquid and heavy components to obtain a recovered hydrocarbon light liquid.

7. A method for producing treated oil for blending with crude oil as described in claim 4 or 5, characterized in that it has a third mixing process in which the treated oil for blending with crude oil (C) is mixed with the crude oil (C) in the process line of the crude oil (C).

8. A processed oil for blending with crude oil, obtained by carrying out the method for producing a processed oil for blending with crude oil according to any one of claims 4 to 7.

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