JPH03212490A - Method for simultaneous treatment of coal and petroleum-based heavy oil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for co-processing coal and petroleum-based heavy oil, in particular, a method in which coal and petroleum-based heavy oil are first hydrotreated and then distilled and separated. The present invention relates to a method for co-processing coal and petroleum-based heavy oil, which is then hydrotreated again.

(Conventional technology) In the wake of the so-called oil shock in 1971, coal was reconsidered as a transitional energy source due to its abundant resources and small distribution of production areas, and became one of the technologies for developing new fuel oil. Research and development on coal liquefaction has been progressing worldwide. However, the recent slump in the oil situation has slowed down the pace of technological development in coal liquefaction due to its economic viability, but there is no doubt that the oil supply capacity will begin to decline in the 21st century. It is clear that in order to continue to secure sufficient supply of liquid fuel for transportation, which is one of the largest demand areas for the world, it is necessary to steadily develop manufacturing technology for liquid synthetic fuel.

Under these circumstances, coal liquefaction technology and heavy petroleum oil cracking technology are being developed as technologies that can reduce product manufacturing costs and have the potential to be as price competitive as current petroleum products. Progress is being made in the development of technology for simultaneous processing of combined coal and petroleum-based heavy oil, or "co-processing."

In co-processing, the circulating solvent in the coal liquefaction process is replaced with petroleum-based heavy oil and the slurry is hydrocracked to obtain a product, so securing the solvent fraction, which was essential in the coal liquefaction process, is basically unnecessary. If this technology can be commercialized using existing oil refining technology, significant cost reductions will be possible.

In addition, residual carbon, metals, sulfur, nitrogen, etc. exist as impurities in heavy petroleum oil, and these impurities become a major hindrance in the hydrocracking reaction of the hydrocracking process of heavy petroleum oil. There is. In other words, asphaltenes and resins, which are represented by residual carbon, are adsorbed on the catalyst and become precursors of coke, while metals such as Ni and 2 are deposited as sulfides on the catalyst surface and in the pores, reducing the activity of the catalyst. In addition, basic nitrogen compounds such as pyridine and quinolines neutralize the active sites and act as temporary catalyst poisons, inhibiting the decomposition reaction. However, it is now known that by adding a small amount of coal to the heavy oil hydrocracking process, the aforementioned hydrocracking obstacles can be eliminated.

In other words, it has been revealed that the addition of coal has the effect of preventing coke deposition in the reactor and removing metals (■, Nt) from the liquid product, and this is evaluated as a major advantage of co-processing.

In other words, regarding the co-processing technology, (1) it is a technology that serves as a bridge between current oil refining technology and coal liquefaction technology.

(2) Compared to the coal liquefaction process, it is not necessary to secure a circulating solvent, and the process configuration is relatively simple. In addition, low hydrogen consumption improves economic efficiency.

(3) It is possible to remove metals from petroleum residue and diversify products.

(4) Hydrocarbon fuel equipment can be effectively utilized through continuous use.

(5) The lifespan of oil will be extended by reducing the amount of oil used.

The establishment of this technology is of great significance.

FIG. 2 shows a basic process flow of co-processing in the prior art.

As can be seen from the figure, coal and petroleum-based heavy oil are preheated and sent to a reactor together with hydrogen gas in the form of a slurry, where they are hydrocracked in the presence of an iron-based catalyst and then distilled into a specified distillate. Separated by minutes. In some cases, a portion of the remaining oil bones is returned to the slurry preparation stage. The coal to be treated at this time is from sub-bituminous coal to bituminous coal, and both normal pressure residual oil and vacuum residual oil can be used as petroleum heavy oil. The concentration of coal is 30
~60% (by weight) of residual oil in the distillation stage to suppress the increase in slurry viscosity that can cause pump troubles when using vacuum residual oil for slurry preparation or in the case of slurry with a high coal concentration. A portion of the slurry may be recycled as a solvent for slurry preparation.

The co-processing reaction is carried out at a temperature of 400-450°C under hydrogen gas pressure.
It is often carried out at a pressure of 120 to 200 atmospheres. The properties of the produced oil are between petroleum-based and coal-based produced oils, but the high-boiling fraction is close to petroleum-based, and the heavy oil is said to be produced in large quantities from petroleum.

Regarding the yield, there are reports that the yield is higher than that of single treatment, but there are also reports that the yield is lower, so the evaluation has not been determined.

(Problems to be Solved by the Invention) Generally, petroleum-based heavy oils are less aromatic than coal-based oils and do not have hydrogen-donating properties, so they have no affinity with coal and no ability to inhibit polymerization when dissolving coal. As a countermeasure to this problem, a method has been adopted in which heavy petroleum oil is hydrotreated in advance.

For example, JP-A-55-25407, JP-A-55-
Publication No. 125189 discloses, as one of the coal liquefaction technologies, a method in which a partially hydrogenated fraction of petroleum thermal cracking or catalytic cracking oil with a boiling point of 200 to 450°C is used as a part of the solvent. However, since this hydrotreatment is carried out before mixing with coal, petroleum that has not been demetalized has V % N + s as mentioned above.
It contains metal atoms such as Fe, which has the disadvantage of poisoning the hydrogenation catalyst and causing a decrease in activity.

In addition, JP-A-58-61179 discloses that in a coal liquefaction method using petroleum as a solvent, the reaction is divided into a coal dissolution zone and a hydrogenolysis reaction zone, so that metals in petroleum are combined with coal residue in the dissolution zone. However, in this method, the dissolution zone and the hydrogenolysis reaction zone are separated by a cooling zone. Because they are sandwiched and connected, metals are bound together and the attached coal residue is introduced into the hydrogen cracking reaction zone without being separated. For this reason, it has become clear that dissociation and desorption of metal from the coal residue occur in the hydrogenolysis reaction zone, resulting in poisoning of the hydrogenation catalyst.

In addition, regarding the recirculation of residual oil with the expectation of increasing the donor hydrogen concentration, the recirculation ratio is usually 0.3 to 1.0 on a weight basis.
However, according to experimental results when the ratio was changed, both the coal conversion rate and the desulfurization/denitrification rate decreased, and it was reported that the smaller the amount of recirculation, the better. The reason for this is said to be that an increase in the recirculation ratio reduces the hydrogen content in the residual oil, resulting in poor reactivity.

Furthermore, in the conventional method, a fraction with a boiling point of 350 to 538 DEG C. was directly extracted as a product, but this fraction has the drawbacks of being highly toxic and having a high content of N and S, making it difficult to use as a product. Furthermore, since petroleum heavy oil contains a relatively large amount of this high-boiling point fraction, a large amount of this fraction will be included in the product in the co-processing, which is disadvantageous in obtaining the product.

The present invention aims to solve these problems and provide a more effective treatment method.

(Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted extensive research and have obtained the following findings, leading to the completion of the present invention.

In other words, in contrast to the conventional co-processing method which has the above-mentioned drawbacks, the present invention first performs a hydrogenolysis reaction using an inexpensive iron-based catalyst, and then separates the reaction product by distillation. This is a method for co-processing coal and petroleum heavy oil, which eliminates these drawbacks by hydrogenating the heavy fraction again and using part or all of it as part of the solvent.

That is, the gist of the present invention is a slurry preparation step of preparing a mixed slurry of coal, petroleum-based heavy oil, and a solvent, preferably at a reaction temperature of 400 to 47°C.
0°C, reaction pressure 150-200 atm, reaction time 30-9
A first hydrogenation stage in which a hydrogenation reaction is carried out using an iron-based catalyst under a reaction condition of 0 minutes; a separation stage in which the hydrogenation reaction product is fractionated using a distillation method, of which the boiling point is 350-538°
A second hydrogenation stage in which the C fraction is hydrogenated again using a hydrogenation catalyst, and a circulation stage in which part or all of this hydrogenation product is recycled for use as part of the solvent. This is a method of co-processing coal and petroleum-based heavy oil.

Here, "petroleum-based heavy oil" refers to residual tower bottom oil from petroleum refining, and specifically includes atmospheric distillation residue and vacuum distillation residue. Coal is supplied in the form of powder, and usually powder with an average particle size of 0.03 to 0.20+mm is used.

(effect) FIG. 1 shows the process flow of the method according to the invention.

In the figure, in the slurry adjustment stage, preferably 0.06 to 0.
．． A mixed slurry is prepared by mixing coal powder pulverized to 15 mm, petroleum heavy oil such as distillation residue, and hydrogen gas. The mixed slurry at this time is placed under high pressure, heated to 400 to 470''C through a preheating step if necessary, and then sent to the first hydrogenation step.

In the case of the present invention, an iron-based catalyst is preferably used in the first hydrogenation stage because the catalyst is severely poisoned in the hydrogenation reaction at this stage and is required in large quantities. This is because they are required to be inexpensive. This iron-based catalyst includes red mud, iron ore, steel mill waste,
Examples include iron-based compounds such as waste from coal gasifiers,
Although not particularly limited thereto, such an iron-based catalyst is used in an amount of 1 to 10% by weight based on the raw material slurry, and a sulfur compound is used as a promoter in an amount of 1 to 10% by weight in the same manner as the iron-based compound.
% is preferred.

For example, when the above-mentioned iron-based catalyst is used, the hydrogenolysis reaction in the first hydrogenation stage is carried out at a temperature of 400 to 470 degrees per reaction part.
C1 reaction pressure 150-200 atm, reaction time 30-90
It can be carried out under reaction conditions of minutes.

For batchwise processing, a high-pressure vessel such as an autoclave can be used, but for continuous processing, a high-pressure reaction tower is used, and the pressure is returned to normal pressure through several stages of pressure reducing valves. The reaction product is fed to the next separation stage.

In this separation step, the hydrocracking reaction product is fractionated at normal pressure or under reduced pressure. This separates it into a gas component, a liquid component, and a residue. According to the present invention, a fraction of the liquid components having a boiling point of 350 to 538° C. is sent to a second hydrogenation stage to be described later, and after hydrogenation again, it is recycled as a solvent to the slurry preparation stage.

In this second hydrogenation step, since poisonous substances have been removed, it is possible to use commonly used highly active hydrogenation catalysts. Nj M as a highly active catalyst
Examples include catalysts such as CoMo/AQtOz and CoMo/AQtOz, and the reaction format may be an ebullated bed or a moving bed, but generally a fixed bed reaction column is used.

The reaction conditions in this case are, for example, hydrogen gas pressure, temperature 250-400°C, pressure 50-150 atm, LH3V
0.1-2.0 is preferable.

The fraction recovered in this way is sent to the slurry preparation stage, but the mixing ratio of the fraction as a circulating solvent at this time is equivalent to that of heavy petroleum oil, considering product production efficiency, etc. It is desirable to withdraw the slurry, but if the slurry viscosity is high enough to cause pump trouble, the ratio may be increased to reduce the viscosity. Further, the coal concentration in the slurry is 30 to 60%, preferably 35 to 50%.

As described above, according to the present invention, a mixture of petroleum heavy oil and coal is first hydrogenated in the first hydrogenation step, preferably using an iron-based catalyst, thereby producing a liquid product from each of them. At the same time, metals that are toxic to the hydrocracking catalyst can be removed from the liquid product, and asphaltenes, resins, etc. that cause coke deposition can also be removed at the same time. This is because toxic metal components are adsorbed or bonded to coal residue, forming a metal-mechanical complex that is removed from the liquid product, and high carbon components are also adsorbed to coal residue or bonded to hydrogen-donating solvents. This is because they are removed by improving hydrogen transfer.

In addition, in the separation step from the obtained liquid product, boiling point 3
By distilling and separating the fraction at 50 to 538°C, fractions with poor product value such as residual liquid can be removed and the added value of the liquid product as a product can be increased. As mentioned above, the liquid product obtained by co-processing coal and petroleum-based heavy oil using iron-based catalysts contains almost no metals harmful to hydrocracking catalysts, which means that distillation separation Metals are not contained in these fractions removed by the process, and therefore these fractions can be easily subjected to hydrocracking treatment, which increases product yield by lightening the product and reduces sulfur and sulfur. Detoxification can be easily achieved by removing nitrogen. Moreover, the most important point is that these fractions are rich in aromaticity and can be endowed with hydrogen-donating properties by hydrogenating them. In other words, by recycling part or all of these hydrotreated fractions as a solvent with hydrogen donating properties in the raw material preparation stage of co-processing, it is possible to further facilitate the hydrocracking of heavy oil and coal. can be carried out, and the conversion rate to these products can be greatly increased.

The present invention will be explained in more detail by way of examples.

Example 1 Specific gravity 1.02, vanadium 270 ppm, nickel 9Q
Vacuum distillation residual oil produced in petroleum refining containing 1 ppm
2 for Australian sub-bituminous coal crushed to less than 0.00 mesh.
In addition, 311 t% of coal gasifier dust was added to the amount of coal as an iron-based catalyst, and powdered sulfur was added as a co-catalyst by 1) 2 times the weight of the iron-based catalyst, and the resulting mixed slurry was electromagnetically heated. Initial hydrogen pressure 70 atm (final pressure 170 atm) in a stirred autoclave, reaction temperature 450'C.
When reacted for 1 hour, the liquid yield was 73% and the desulfurization rate was 85%.
The denitrification rate was 75%, and the metal removal rate was 93%.

The liquid product thus obtained was distilled under atmospheric pressure to a boiling point of 3.
The fraction at 50 to 538°C was separated and collected, and it was placed in an autoclave together with a catalyst obtained by pre-sulfurizing an Os catalyst to Ni Mo/8Q, a hydrogen cracking catalyst, at an initial hydrogen pressure of 50 atm (final pressure). 100 atm), reaction temperature 320°C
The same vacuum residue and coal as mentioned above were mixed in equal weight proportions to the solvent obtained by reacting for 1 hour, and an iron-based catalyst was added in an amount of 3 wt% to the vacuum residue, which is petroleum-based heavy oil. In addition, powdered sulfur was added as a cocatalyst to the vacuum residual oil.
．． 5 wt% was added and the resulting mixed slurry was reacted for 1 hour at an initial hydrogen pressure of 70 atm (final pressure of 170 atm) and a reaction temperature of 450'C in a magnetic stirring autoclave.
The liquid yield was 81%, the desulfurization rate was 86%, the denitrification rate was 75%, and the demetalization rate was 95%.

It can be seen that by recycling the hydrogenated solvent, all of the liquid yield, desulfurization rate, denitrification rate, and demetalization rate are improved.

Example 2 The same raw material used in Example 1 was hydrogenated according to the flow shown in FIG. i.e. vacuum resid and coal and hydrotreated boiling point 350-538°C produced in a later stage.
The fractions were mixed in equal weight proportions and sent together with an iron-based catalyst and powdered sulfur as a co-catalyst to a reaction tower having a processing capacity of 0.5 kgf/h.

The operating conditions of the reactor are shown in Table 1. Note that the amount of catalyst added is a weight ratio to the supplied coal (dry coal standard).

After gas was separated from the reaction products in Table 1 by gas-liquid separation, the liquid was separated into distillate oil and residue by atmospheric distillation or vacuum distillation.

Of the distillate oil, the fraction with a boiling point of 350 to 538 °C is further added to 300 °C.
The mixture was fed into a fixed bed hydrogenation reactor having a catalyst bed of ml. The operating conditions of this hydrogenation reactor are shown in Table 2.

Table 2 This hydrogenation reaction product was initially used as a solvent for the reaction using an iron-based catalyst, and these operations were repeated until a steady state was reached. The reaction results at that time are shown in Table 3.

Table 2 (Effects of the Invention) As described above, according to the present invention, for example, metals harmful to the hydrogenation catalyst are removed by first performing hydrogenation treatment using an inexpensive iron-based catalyst, and then the obtained Among the liquid products obtained, the 350-53B"C fraction, which has poor product value, is separated by distillation and then subjected to hydrogenation treatment to lighten it and make it harmless. Furthermore, it enhances the hydrogen-donating property derived from aromatics and makes it suitable for use in petroleum. The practical benefits of recycling heavy oil and coal as part of the solvent in the co-processing of coal to increase the efficiency of their conversion to liquid products are significant.

[Brief explanation of drawings]

FIG. 1 is a block flow diagram of co-processing in the present invention,
and FIG. 2 is a block flow diagram of co-processing in the conventional method.

Claims (2)

[Claims] (1) A slurry preparation step in which a mixed slurry of coal, petroleum-based heavy oil, and a solvent is prepared; a first hydrogenation step in which the resulting mixed slurry undergoes a hydrogenation reaction in the presence of hydrogen; a hydrogenation reaction product is A separation step in which fractions are fractionated using a distillation method, a second hydrogenation step in which a fraction with a boiling point of 350 to 538°C is hydrogenated again using a hydrogenation catalyst, and a part or all of this hydrogenated product is A process for co-processing coal and petroleum-based heavy oil, characterized in that it consists of a recirculating stage for use as part of the solvent. (2) The hydrogenolysis reaction in the first hydrogenation step was carried out using an iron-based catalyst at a reaction temperature of 400 to 470°C and a reaction pressure of 1
The method according to claim 1, which is carried out under reaction conditions of 50 to 200 atmospheres and reaction time of 30 to 90 minutes.