JPH0245674B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for fluid catalytic cracking of heavy oil, and more specifically, among heavy oils containing distillation residues containing nickel, vanadium, iron, sodium, etc., heavy oils containing more nickel than vanadium are used. By catalytically cracking oil using a catalyst with a specific surface area of 200 m ² /g or less and a zeolite content of 17 wt% or less, dry gas (hydrogen, methane, ethane, ethylene), coke, liquefied petroleum gas (LPG) and It lowers the gasoline yield and increases the middle distillate (boiling range 200-350°C) yield. In normal fluid catalytic cracking, petroleum hydrocarbons are cracked by contacting them with a catalyst to obtain a large amount of light components such as dry gas, LPG, and gasoline, and a small amount of cracked light oil, and then the coke deposited on the catalyst is removed by air. The catalyst is removed by combustion and recycled for reuse. In addition, feedstock oils have traditionally been light gas oil (LGO) from atmospheric distillation columns, heavy gas oil (HGO), and vacuum gas oil (VGO) from vacuum distillation columns.
Only so-called distillate oils such as these are mainly used. However, recently, the world's crude oil has become heavier,
In addition, as the demand structure in Japan has changed, there has been a tendency for heavy oils to be in surplus from both the supply and demand perspective, so it has become necessary to target heavy oils containing distillation residues as feedstock oil for fluid catalytic cracking. . However, heavy oil containing distillation residue contains much higher amounts of metals such as nickel, vanadium, iron, copper, and sodium than distillate oil, and these metals are not present on the catalyst. It is known that it accumulates and significantly inhibits the activity and selectivity of degradation. In other words, as metals accumulate on the catalyst, the decomposition rate decreases, making it practically impossible to achieve the desired decomposition rate, while the amount of hydrogen and coke generated increases significantly, making it difficult to operate the equipment. At the same time, the yield of the desired liquid product is reduced. In order to minimize the effects of these metals, currently commercially available metal-resistant catalysts are characterized by a higher zeolite content than conventional distillate oil cracking catalysts, and are capable of reducing the amount of metal deposited up to about 1wt%. It is said to be effective in maintaining a practical decomposition rate and reducing the amount of hydrogen generated to some extent. However, when these commercially available metal-resistant catalysts were used to decompose southern heavy oil, they were effective in suppressing to some extent the amount of hydrogen generated that increases as metals accumulate on the catalyst, and the decomposition rate was only slightly reduced. Although it was observed that a small but high cracking rate was maintained, the yields of coke, LPG, and gasoline were high, and the yield of the middle distillate, light cracked gas oil (LCO), was found to be low. In Japan's recent supply and demand structure for petroleum products, gasoline is in balance, but there is a shortage of middle distillates, and carbon
There is a large surplus of heavy oil, and this trend is expected to further accelerate in the future, so cracking the surplus heavy oil to obtain a large amount of the middle distillate, which is in short supply, will be an important issue for Japan in the future. There is. Therefore, cracking southern heavy oil using currently commercially available metal-resistant catalysts is not suitable for obtaining a large amount of middle distillates, although it is effective in suppressing the amount of hydrogen generated. do not have. The present invention provides a method for fluid catalytic cracking of heavy oil that solves these problems. In detail, when cracking heavy oil, we suppress the amount of hydrogen and coke produced, and at the same time reduce the yield of LPG and gasoline.
This is a method to obtain a large amount of middle distillate. That is, in the present invention, heavy oil containing a distillation residue containing a total amount of nickel and vanadium of 0.5 ppm or more and containing nickel by weight or more than vanadium is mixed with silica having a specific surface area of 20 to 200 m ² /g.
Fluid catalytic cracking is carried out in the presence of a catalyst containing 17 wt% or less of zeolite in an alumina, silica-magnesia, or magnesia-alumina matrix to increase the yield of middle distillates with a boiling point of 200 to 350°C from 20 to 50 vol%.
A method for fluid catalytic cracking of heavy oil is provided. The present invention will be explained in more detail below. Heavy oil as used in the present invention means that it contains substantially 0.5 ppm or more in total of nickel and vanadium, and also contains more nickel than vanadium, for example, nickel is more than 2 times the weight of vanadium, preferably means more than 4 times the weight. If the amount of nickel is less than 2 times the weight, the decomposition activity of the catalyst due to vanadium will be reduced,
At zeolite contents below 17 wt%, no substantial decomposition occurs. An example of this is southern heavy oil, which is derived from the Minas, Sinta, Duly, Handail, Tarakan, Ataka, and Pukapai crude oils produced in and around Indonesia, as well as the Daqing and Shengli crude oils produced in China. This applies to heavy oil. Heavy oil may be derived from one type of crude oil or a mixture of two or more types of crude oil, and may also be derived from crude oil of non-southern origin, such as Middle Eastern origin, African origin, North and South America origin, Mexican origin, etc.
Heavy oil that is a mixture of North Sea and Alaskan crude oil may also be used. Furthermore, the heavy oil referred to here includes substantially asphaltene or resin content (usually 0.5wt).
% or more) is a hydrocarbon-based mineral oil that contains residual components separated by distillation during the petroleum refining process, specifically atmospheric distillation residue oil, vacuum distillation residue oil, solvent deasphalting. oil, solvent-deasphalted asphalt, and any of these and distillate oils with a normal boiling point of 200°C or higher from atmospheric distillation or vacuum distillation (e.g.
LGO (boiling point range 200-300℃), HGO (300-500℃)
and VGO (300 to 570°C, preferably VGO is used). The mixed oil has a residual oil content of 1 wt% or more. Examples of the heavy oil mentioned here include shale oil, tar sand oil, and coal liquefied oil. The catalyst used in the present invention consists of an amorphous part called a matrix and a crystalline aluminosilicate part called a zeolite. The matrix is preferably a synthetic product containing silica-alumina, silica-magnesia or magnesia-alumina as a main component, or a matrix treated with naturally occurring clay minerals. The zeolite is preferably a synthetic Y-type zeolite belonging to the faujasite family, preferably one in which an exchangeable cation, such as sodium, is exchanged with hydrogen and/or a rare earth metal.
The specific surface area of the catalyst is 20 to 200 m ² /g in the new catalyst state.
It is preferably 30 to 150 m ² /g.
The reason for this is not completely clear, but the increasing yield of hydrogen and coke is suppressed by the metals accumulated on the catalyst, and the coke on the catalyst is Not only is the load on the air blower supplying the combustion air reduced, but the yield of the desired liquid product is increased. The zeolite content in the catalyst is in the new catalyst state.
The content is preferably 17 wt% or less, preferably 1 to 16 wt%, and more preferably 3 to 15 wt%. Currently commercially available metal-resistant catalysts have a zeolite content of 18wt% or more, which is good for increasing gasoline yield, but is not suitable for obtaining a large amount of middle distillate from heavy oil, which contains more nickel than vanadium. Appropriate.
The present invention is based on the discovery that middle distillate yields can be economically increased from heavy oils containing more nickel than vanadium by adjusting the specific surface area and zeolite content of the catalyst. A specific method for using the catalyst is to periodically replenish the amount of the new catalyst of the present invention necessary to maintain the amount of metal accumulated on the catalyst within a certain range within the fluid catalytic cracker, and to reduce losses during operation. This is to remove the catalyst in use from the equipment in an amount that corresponds to the amount of replenishment.
The amount of replenishment depends on the amount of heavy oil to be treated, the metal content in the heavy oil and the metal accumulation capacity of the catalyst. The higher the metal accumulation capacity of the catalyst, the smaller the amount of replenishment is required, providing an economical heavy oil cracking method. It has been discovered that the catalyst according to the present invention suppresses hydrogen and coke production within the normally acceptable range up to a metal accumulation of 2 wt%, and also has a high middle distillate yield.
It was found that it is an economically excellent catalyst that requires only a small amount of supply. The apparatus used in carrying out the present invention, that is, the fluid catalytic cracking apparatus having a reaction zone, a separator, a stripping zone, a catalyst regeneration zone, and a distillation zone is not particularly limited, but is suitable for substantially cracking heavy oil. It is desirable that the For example, the reaction zone should preferably be equipped with a riser reaction zone to shorten the contact time between oil and catalyst and reduce the amount of coke produced, and the regeneration zone should be equipped with equipment that can withstand high temperatures up to about 750°C or heat removal equipment. What you have is good. In addition, the operating conditions of the device are not particularly limited, but an example is a reaction temperature of 450 to 550°C, a pressure of 0.5
~3Kg/ ^cm2G , catalyst regeneration temperature 550~750℃, catalyst/
Oil ratio 3~20wt/wt, contact time 0.5~5sec, CFR
((New feedstock oil + circulating oil)/New feedstock oil) 1.0~2.0vol/
It is vol. The decomposition rate is important for increasing the middle distillate yield, and the definition of the decomposition rate is as follows: decomposition rate = Feedstock oil - distillate with boiling point of 200℃ or higher / Feedstock oil x 100 (
vol%), the decomposition rate is 30-70vol%, preferably
A range of 40 to 60 vol% is preferable. If the cracking rate is high, a large amount of gasoline will be obtained and the yield of middle distillate will be low, but by using the catalyst of the present invention, the cracking rate can be controlled within a desired range. The yield of the middle distillate of the present invention is 20 to 50 vol%, preferably 25 to 40 vol%. In addition, the method of calculating the yield of the middle distillate is based on the substance at 350° C. or higher in the raw material, and is determined by the following formula. Middle distillate yield (vol%) = product (200-350°C)/substances above 350°C in the raw material x 100 The process of the present invention will be more clearly understood from the following examples. Examples 1 to 3 and Comparative Examples 1 to 3 In order to compare the nickel resistance of the catalyst, the surface area,
Six kg of each of six types of new catalysts (A to F) with different zeolite contents were calcined at 600°C for 3 hours, impregnated with nickel naphthenate, supported with a predetermined amount of Ni, and then steamed at 760°C for 6 hours. . Each steaming treatment catalyst (4 kg) was packed into a circulating flow bench device and subjected to Daqing atmospheric distillation under the following conditions: reaction temperature 460℃, regeneration tower temperature 600℃, normal pressure, catalyst/oil ratio 7.0, and raw material supply rate 10.5g/min. A catalytic cracking reaction was carried out on feedstock oil consisting of 20 parts of residual oil and 80 parts of desulfurized vacuum gas oil (VGO). Table 1 shows the physical properties and reaction results of the new catalyst.

[Table] Note 1: Value for new catalyst The hydrogen/methane ratio is often used as an indicator of metal poisoning that is not affected by the conversion rate, and the higher the ratio, the greater the effect of metal poisoning. Each catalyst is about 7000~
It shows a Ni accumulation amount of 20000ppm, but catalyst A,
Compared to B, C, and D, E and F, which have a larger surface area, had a hydrogen/methane ratio about twice as high and showed inferior metal resistance. It can be seen that Catalyst D has high cracking activity and low middle distillate yield, although metal resistance is observed. Although catalyst A accumulated 19,600 ppm of Ni, it showed excellent results in both metal resistance and middle distillate yield, and good results were also obtained for catalysts B and C. Examples 4 to 5 and Comparative Example 4 Three types of new catalysts (G, H, I) were each charged at 40 kg into a circulating flow type pilot plant, and a catalytic cracking reaction of atmospheric distillation residue oil was carried out under predetermined conditions. The crude oil composition ratio of the atmospheric residual oil is shown in Table 2, and the physical properties of the catalyst, reaction conditions, and reaction results are shown in Table 3.

[Table] Note 1: Oil-soluble nickel was added to the raw oil to accelerate metal accumulation.

【table】

【table】

[Table] Note 1: Values for new catalyst Catalysts G, H, and I all had low hydrogen/methane ratios and were found to be metal resistant. It was also found that the dry gas flow rate increased by 50 to 80 scf/bbl and the coke yield increased by 1 to 2 wt% until nickel on the catalyst reached the respective accumulated amounts from zero, which is sufficient for practical use. However, Catalyst I has high decomposition activity;
It is an unsuitable catalyst for obtaining a large amount of middle distillates.

Claims (1)

[Scope of Claims] 1. In a method of fluidly contacting heavy oil containing distillation residue containing a total of 0.5 ppm or more of nickel and vanadium, a heavy oil having a nickel content of 2 times the vanadium content or more by weight as a feedstock oil. using
Silica with a specific surface area of 20 to 200 m ² /g as a catalyst
Alumina, silica-magnesia or magnesia
A catalyst containing up to 17% by weight of gelaite in an alumina matrix is used, thereby achieving a boiling point of 200%.
A process characterized in that a middle distillate at ~350°C is obtained in a high yield of 20-50% by volume. 2 Claims in which the heavy oil is an atmospheric distillation residue oil, a vacuum distillation residue oil, a solvent deasphalted oil, a solvent deasphalted asphalt, or a mixed oil of any of these and a distillate oil from atmospheric distillation or vacuum distillation. The method described in paragraph 1. 3. The method according to claim 1 or 2, wherein the catalyst has a specific surface area of 30 to 150 m ² /g. 4. The method according to claim 1, 2 or 3, wherein the gelaoite is Y-type haujasite in which exchangeable cations are exchanged with hydrogen and/or rare earth metals.