JP7688558B2 - Hydrogenated oil manufacturing method and fuel alternative method - Google Patents

Description

The present invention relates to a method for producing hydrogenated oil and a fuel alternative method.

In steelworks that have iron-making plants and rolling mills, coke oven gas generated in coke ovens is used as fuel for heating furnaces, etc. However, since there are restrictions on the gas supply balance within the steelworks, there are cases where the amount of coke oven gas supplied is limited, making it necessary to use fuels other than coke oven gas (also called "alternative fuels").

As a fuel other than coke oven gas, petroleum-derived raw materials with low nitrogen and sulfur content are purchased and processed to produce by-product oil, which is used as an alternative fuel, enabling high operation rates of facilities. However, due to current changes in the market, it is becoming more difficult to purchase petroleum-derived raw materials, and there is a demand for alternative fuels that do not rely on petroleum-derived raw materials.

For example, Patent Document 1 discloses a method in which aromatic hydrocarbon compounds separated from crude light oil, which is a light oil produced during the coking of coal, are desulfurized by contacting them with hydrogen in the presence of a hydrodesulfurization catalyst, and then used as a chemical raw material. In this specification, aromatic hydrocarbon compounds that have been separated from crude light oil and then hydrogenated are also referred to as hydrogenated oil.

JP 2010-106057 A

Because aromatic hydrocarbon compounds separated from crude diesel contain sulfur, they cannot be used as alternative fuel unless this sulfur is removed. However, the technology of Patent Document 1 does not always allow for stable removal of sulfur, making it difficult to stably produce hydrogenated oil with a low sulfur content.

In addition, aromatic hydrocarbon compounds also contain nitrogen, so in order to use aromatic hydrocarbon compounds as alternative fuels, it was also necessary to stably remove the nitrogen.

Therefore, the present invention has been made with a focus on the above problems, and aims to provide a method for producing hydrogenated oil and a fuel alternative method that can stably produce hydrogenated oil with low sulfur and nitrogen contents.

According to one aspect of the present invention, a method for producing hydrogenated oil is provided, which includes a supply step of supplying multiple types of crude light oils having different concentrations of heavy components and aromatic hydrocarbon compounds to a pre-distillation tower, a pre-distillation step of separating the multiple types of crude light oils into heavy components and aromatic hydrocarbon compounds in the pre-distillation tower, and a hydrogenation step of adding hydrogen to the aromatic hydrocarbon compounds separated in the pre-distillation step and subjecting them to a hydrogenation treatment, and in the supply step, the supply ratio of the multiple types of crude light oils is within a predetermined range.

According to one aspect of the present invention, a fuel substitution method is provided in which hydrogenated oil produced by the above-mentioned production method is used as an alternative fuel.

According to one aspect of the present invention, a method for producing hydrogenated oil and a fuel substitution method are provided that can stably produce hydrogenated oil with low sulfur and nitrogen contents.

FIG. 1 is a schematic diagram showing a hydrogenated oil production facility according to one embodiment of the present invention. 1 is a graph showing the results of an example, in which (A) is a trend showing the feed ratio of crude light oil, and (B) is a trend of the content of heavy components and aromatic hydrocarbon compounds contained in the crude light oil. 1 is a graph showing the relationship between reaction time and nitrogen concentration in an example. 1 is a graph showing the relationship between reaction time and sulfur concentration in an example.

In the following detailed description, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, identical or similar parts are given the same or similar reference numerals, and duplicate explanations will be omitted. The drawings are schematic and may differ from the actual product. In addition, the embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not specify the materials, structure, arrangement, etc. of the components as described below. The technical concept of the present invention may be modified in various ways within the technical scope defined by the claims.

<Hydrogenated oil manufacturing facility>
1 shows a hydrogenated oil production facility 1 according to one embodiment of the present invention. The production facility 1 includes two tanks 2A and 2B, a pre-distillation column 3, and a hydrogenation reactor 4.

Crude light oil is a type of light oil produced during the coking of coal, and is mainly collected from coke oven gas. Crude light oil contains heavy components, which are high-boiling point components, and aromatic hydrocarbon compounds, which are low-boiling point components. The heavy components of crude light oil are mostly compounds containing 9 or more carbon atoms, including naphthalene, indene, and styrene. The aromatic hydrocarbon compounds are mostly benzene, toluene, and various xylenes.

The two tanks 2A and 2B store crude light oils of different components. The crude light oils have different components due to differences in the coke ovens and differences in the operating conditions of the coke ovens. Specifically, the crude light oils have different components meaning that the ratio of the content of heavy components to aromatic hydrocarbon compounds is different. In this embodiment, the crude light oils generated from different coke ovens, coke oven a and coke oven b, may be stored in tanks 2A and 2B, respectively.

The pre-distillation tower 3 is a device that distills the crude light oil supplied from at least one of the two tanks 2A and 2B, and separates it into heavy components, which are high boiling point components, and aromatic hydrocarbon compounds, which are low boiling point components. The heavy components and aromatic hydrocarbon compounds separated in the pre-distillation tower 3 are extracted from the bottom and top of the pre-distillation tower 3, respectively, and sent to the next process. In addition, the aromatic hydrocarbon compounds separated in the pre-distillation tower 3 are sent to the hydrogenation reactor 4, and hydrogen is added in the supply path.

The hydrogenation reactor 4 is a device that performs hydrogenation treatment on the aromatic hydrocarbon compounds separated in the pre-distillation column 3. In the hydrogenation reactor 4, the aromatic hydrocarbon compounds of the crude light oil are contacted with hydrogen in the presence of a hydrodesulfurization catalyst under high temperature and pressure, causing a hydrogenation reaction. This removes sulfur and nitrogen from the aromatic hydrocarbon compounds (denitrification and desulfurization). The aromatic hydrocarbon compounds that have been subjected to hydrogenation treatment then become hydrogenated oil.

<Method of producing hydrogenated oil>
The method for producing hydrogenated oil according to this embodiment will be described. In this embodiment, first, two types of crude light oil having different contents of heavy components and aromatic hydrocarbon compounds are supplied from two tanks 2A and 2B to the pre-distillation column 3 (supply step). In the supply step, the crude light oil is supplied so that the ratio (supply ratio) of the supply amount of the crude light oil (also referred to as crude light oil A) supplied from the tank 2A to the crude light oil (also referred to as crude light oil B) supplied from the tank 2B is constant. The supply ratio of the crude light oil is not particularly limited, but it is preferable to set it to a ratio that allows the mixed crude light oil to be stably supplied based on the supply balance according to the generation amount of the two types of crude light oil. In addition, it is preferable to supply multiple types of crude light oil to the pre-distillation column so that the total content of aromatic hydrocarbon compounds in the multiple types of crude light oil is 76.0% by mass to 84.0% by mass with respect to the total amount of the heavy components and the aromatic hydrocarbon compounds, and the total content of heavy components in the multiple types of crude light oil is 24.0% by mass to 16.0% by mass with respect to the total amount of the heavy components and the aromatic hydrocarbon compounds.

In addition, the supply amount of crude light oil, i.e., the total supply amount of crude light oil A and crude light oil B, is set to be a constant supply amount for a relatively long period of time, such as daily or weekly, depending on the production situation and the supply amount of crude light oil, etc. In other words, in the supply step, two types of crude light oil are supplied to the pre-distillation column 3 at a constant supply ratio and in a constant supply amount.
The specific value of the supply amount is an optimum value depending on the processing amount, the equipment specifications of the pre-distillation column, etc., and is described as an example in the Examples.

After the supply step, the two types of crude light oil supplied are separated into heavy components and aromatic hydrocarbon compounds in the pre-distillation tower 3 (pre-distillation step). In the pre-distillation step, the crude light oil is distilled to separate it into heavy components, which are high boiling point components, and aromatic hydrocarbon compounds, which are low boiling point components. The separated heavy components and aromatic hydrocarbon compounds are then extracted from the bottom and top of the pre-distillation tower 3, respectively. The crude light oil is mainly composed of aromatic hydrocarbon compounds and heavy components. Therefore, by supplying the crude light oil at a constant supply ratio and in a constant supply amount in the supply step, a constant amount of heavy components and aromatic hydrocarbon compounds are each extracted from the pre-distillation tower 3.

After the pre-distillation process, hydrogen is added to the aromatic hydrocarbon compounds separated in the pre-distillation process, and hydrogenation is performed (hydrogenation process). In the hydrogenation process, hydrogen is added to the aromatic hydrocarbon compounds extracted from the pre-distillation column 3, and the resultant product is sent to the hydrogenation reactor 4. Then, under high temperature and pressure, the aromatic hydrocarbon compounds of the crude light oil are contacted with hydrogen in the presence of a hydrodesulfurization catalyst, causing a hydrogenation reaction and carrying out the hydrogenation process. In the hydrogenation process, the aromatic hydrocarbon compounds are denitrified and desulfurized. The hydrogenated aromatic hydrocarbon compounds are then extracted from the hydrogenation reactor 4 as hydrogenated oil.

The reaction temperature and reaction time in the hydrogenation step are not particularly limited, but for example, the hydrogenation process may be performed so that the reaction temperature is 300°C or higher and 320°C or lower, and the reaction time is 2600 seconds or higher and 3000 seconds or lower. The reaction temperature and reaction time are appropriately set depending on the amount of aromatic hydrocarbon compound supplied and the dimensions and specifications of the hydrogenation reactor 4.

In the hydrogenation process, if the supply amount of aromatic hydrocarbon compounds fluctuates, the reaction time also fluctuates, making it impossible to perform denitrification and desulfurization stably. In addition, if the supply amount of aromatic hydrocarbon compounds fluctuates in the hydrogenation process, the temperature (reaction temperature) in the hydrogenation reactor 4 changes, which is also a factor in making it impossible to perform denitrification and desulfurization stably. However, in this embodiment, since crude light oil is supplied at a constant supply ratio and in a constant supply amount in the supply process, aromatic hydrocarbon compounds are supplied to the hydrogenation reactor 4 in a constant supply amount. Therefore, the hydrogenation process can be performed at a stable temperature and stable processing time, and hydrogenated oil with a stable low nitrogen content and sulfur content can be produced.

The hydrogenated oil produced in this manner can be used as an alternative fuel for heating furnaces, etc. The hydrogenated oil produced by the production method according to this embodiment has a low sulfur and nitrogen content, so it is possible to reduce the amount of sulfur and nitrogen oxides emitted from heating furnaces.

<Modification>
Although the present invention has been described above with reference to specific embodiments, it is not intended that the invention be limited by these descriptions. By referring to the description of the present invention, other embodiments of the present invention including various modifications in addition to the disclosed embodiments will be apparent to those skilled in the art. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments including these modifications described herein, either alone or in combination.

For example, in the above embodiment, crude light oils having two different components are used, but the present invention is not limited to such an example. It is sufficient that multiple crude light oils are used, and for example, crude light oils having three or more different components may be used. Even in this case, it is preferable to mix the crude light oils to achieve a constant supply ratio according to the supply balance according to the amount of each crude light oil generated.

In the above embodiment, the two types of crude light oil are supplied at a constant supply ratio in the supply process, but the present invention is not limited to this example. The supply ratio does not have to be constant and may be set within a predetermined range as long as there is no quality problem with the sulfur content and nitrogen content of the hydrogenated oil produced. For the same reason, the supply amount of the crude light oil may also be set to be within a predetermined range rather than constant. For example, when the hydrogenated oil is used in a heating furnace, the sulfur content and nitrogen content are preferably 2 mass ppm or less. For this reason, as long as the sulfur content and nitrogen content are stable and are 2 mass ppm or less, the supply ratio and supply amount of the crude light oil may each be set to a value having a certain range.

Next, an example carried out by the inventor will be described. In the example, hydrogenated oil was produced using the production equipment shown in FIG. 1 and crude light oil A and crude light oil B, which are two types of crude light oil with different components shown in Table 1, as raw materials. The feed ratio of crude light oil A to crude light oil B was 0.82 and 0.18, respectively, with the total feed amount of crude light oil being 1 (the total content of aromatic hydrocarbon compounds was 81.6% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds, and the total content of heavy components in the multiple types of crude light oil was 18.4% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds). The feed ratio was set according to the amount of crude light oil A and crude light oil B generated. In addition, the examples were carried out over a long period of 88 days, and due to fluctuations in the amount of generation, there was a period in which the feed ratio of crude light oil A to crude light oil B was 0.79 for crude light oil A and 0.21 for crude light oil B (the total content of aromatic hydrocarbon compounds was 81.6% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds, and the total content of heavy components in the plurality of types of crude light oil was 18.4% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds). In addition, in the examples, the reaction temperature in the hydrogenation step was 300 ° C. to 320 ° C., and the reaction time was 2600 seconds to 3000 seconds. Furthermore, in the examples, the feed rate of crude light oil was 16 t / h to 19 t / h, the generation amount of heavy components in the pre-distillation step was 2.5 t / h to 4.5 t / h, and the generation amount of aromatic hydrocarbon compounds in the pre-distillation step was 13.0 t / h to 15.0 t / h. Furthermore, the amount of hydrogen added in the hydrogenation step was 400 Nm ³ /h to 470 Nm ³ /h.

2(A) shows the trend of the feed ratio in the example, and FIG. 2(B) shows the trend of the content of heavy components and aromatic hydrocarbon compounds in the crude light oil fed in the feed process. The feed ratio shown in FIG. 2(A) shows the ratio of the feed amount of crude light oil A (A/(A+B)) when the total feed amount of crude light oil in the feed process is set to 1. The dashed line in FIG. 2 shows the timing when the control of the feed ratio was started, and the feed ratio before the control of the feed ratio in FIG. 2(A) was finely changed according to instantaneous fluctuations in the amount of generated, as in the conventional case. As shown in FIG. 2(B), it was confirmed that the concentration of heavy components and aromatic hydrocarbon compounds in the crude light oil fed in the feed process were stabilized by controlling the feed ratio as in the above embodiment.

Figure 3 shows the relationship between the reaction time of the hydrogenation process and the nitrogen concentration of the hydrogenated oil produced during the period when supply ratio control was not performed and the period when supply ratio control was performed. Also, Figure 4 shows the relationship between the reaction time of the hydrogenation process and the sulfur concentration of the hydrogenated oil produced during the period when supply ratio control was not performed and the period when supply ratio control was performed. It was confirmed that by performing supply ratio control, the reaction time was stable and the nitrogen concentration and sulfur concentration in the hydrogenated oil could be stably reduced to 2 mass ppm or less. In other words, it was confirmed that the hydrogenated oil production method according to the above embodiment can stably produce hydrogenated oil with low nitrogen and sulfur contents.

1 Production equipment 2A, 2B Tank 3 Pre-distillation column 4 Hydrogenation reactor

Claims (2)

A supply step of supplying a plurality of types of crude light oils having different concentrations of heavy components including naphthalene, indene, and styrene and compounds having 9 or more carbon atoms , and aromatic hydrocarbon compounds including benzene, toluene, and xylene , to a pre-distillation column;
A pre-distillation step in which the multiple types of crude light oils are separated into heavy components and aromatic hydrocarbon compounds in the pre-distillation column;
a hydrogenation step in which hydrogen is added to the aromatic hydrocarbon compound separated in the pre-distillation step to perform a hydrogenation treatment;
Equipped with
In the supply step, the total content of aromatic hydrocarbon compounds in the plurality of types of crude light oils supplied to the pre-distillation column is 76.0% by mass to 84.0% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds, and the total content of heavy components in the plurality of types of crude light oils is within the range of 24.0% by mass to 16.0% by mass relative to the total amount of heavy components and aromatic hydrocarbon compounds .
A method for producing hydrogenated oil. A method for replacing fuel, comprising using the hydrogenated oil produced by the method according to claim 1 as an alternative fuel.

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