JPS596242B2 - Catalytic gasification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of continuously catalytically cracking heavy oil having a specific gravity of 0.8 or more to obtain a gas containing very little methane and rich in H2 and CO.

Conventionally, as methods for gasifying light hydrocarbons from petroleum fractions such as natural gas and naphtha, there are known partial oxidation methods using nickel-based catalysts, steam reforming methods, and non-catalytic partial oxidation methods.

However, only non-catalytic partial oxidation methods have been commercialized for the gasification of hydrocarbons containing heavy residual oils such as crude oil, atmospheric residual oil, and vacuum residual oil.

In this method, the reaction temperature is as high as 1300° C. to 1500° C., so the produced gas has a low methane content and is suitable as ammonia, methanol, oxo synthesis gas, and hydrogen gas for hydrogenation.

However, the non-catalytic partial oxidation method has the following drawbacks.

(1) In order to maintain the reaction temperature at a high temperature, a large amount of expensive oxygen or oxygen-rich air is used.

(2) Since high temperatures are obtained, a large portion of the feedstock oil is consumed in combustion, which inevitably reduces the yield of H2 and CO.

(3) Since the reaction temperature is high, high-grade heat-resistant materials are required for constructing the reactor, and its lifespan is short.

(4) Carbon precipitation of 2 to 5% of the feedstock is unavoidable, and as well as reducing H2 and CO yield, excessive equipment costs are required to remove the precipitated carbon and recirculate it to the feedstock, making it economically uneconomical. It is disadvantageous.

Although the method of catalytically gasifying heavy oil has not yet been industrialized, several reports have been made recently.

The main ones are catalysts whose main components are alkali aluminates and calcium aluminates, which are alkaline and alkaline earth complex oxides, respectively, or nickel catalysts containing tungsten compounds, which are brought into contact with heavy oil to generate steam. This method involves gasification through reforming or partial oxidation.

According to these methods, gasification is possible at low temperatures of 850°C to 1100°C, and compared to non-catalytic partial oxidation methods, gasification efficiency is better, the amount of oxygen required is smaller, and there are fewer problems with reactor materials. There is a first point.

Furthermore, the amount of carbon precipitated is small, and the equipment and costs required for recovering the precipitated carbon can be reduced.

However, when heavy oil is gasified using these catalysts, a large amount of lower hydrocarbons, particularly methane, remains in the produced gas.

Methane in the produced gas is a welcome presence when it is used as a fuel gas, but when it is used as a raw material gas for ammonia, methanol oxo synthesis, or hydrogen raw material for hydrogenation, it is
Economically, an increase in the amount of methane remaining is a neo-1 because the O yield rate decreases and extra equipment and energy are required for methane separation.
It is.

As a method to reduce the methane content in the generated gas,
Possible methods include increasing the amount of steam added, increasing the reaction temperature, and increasing the residence time in the reactor, but all of these methods have drawbacks such as increased energy requirements and equipment costs. It was experimentally confirmed that it is difficult to reduce methane.

For the above reasons, the inventors have developed a method that allows continuous catalytic gasification of heavy oil at a low temperature of 850°C to 1100°C, and reduces residual hydrocarbons, especially methane, in the produced gas to virtually zero.
As a result of intensive research with the aim of developing an economical method for extremely reducing the amount, the present invention was successfully completed.

That is, in the gasification method of the present invention, when heavy oil with a specific gravity of 0.8 or more is catalytically gasified using steam or steam and oxygen-containing gas, calcium aluminate and alkali aluminate are first heated at a temperature of 850 to 1100°C. Alternatively, the chromium oxide catalyst or chromium oxide is contacted with a gasification catalyst made of tungsten-containing nickel that causes less carbon precipitation, and then an alkaline earth metal oxide, aluminum oxide, zirconium oxide,
The gist of this is to bring it into contact with a catalyst made by mixing one or more of nickel oxide and cobalt oxide.

That is, after being brought into contact with a known gasification catalyst (hereinafter referred to as the first layer catalyst) which is made of calcium aluminate, alkali aluminate, or tungsten-containing nickel and which causes less carbon precipitation, the catalyst containing chromium oxide as the main component is (hereinafter referred to as the second layer catalyst), the residual methane in the produced gas was successfully reduced to substantially zero or an extremely small amount.

In the method of the present invention, all heavy oils of 0.8 or higher, regardless of the presence or absence of residual oil, are used as raw materials, from light oil, vacuum gas oil, ethylene bottom oil, etc. to crude oil, atmospheric residual oil, vacuum residual oil, etc. I can do it.

In addition to these excellent features, this gasification method also has the extremely important feature that it can be gasified without causing carbon precipitation on the catalyst and without being poisoned by sulfur. There is.

Fe, CO, and Ni-based catalysts used in conventional methods are
Although it is known to have excellent performance in reducing methane, carbon tends to precipitate, resulting in a decrease in catalyst performance, or in the case of a fixed bed, clogging the catalyst bed and making it impossible to operate. Confirmed experimentally.

In this case, increasing the amount of water vapor added is effective in preventing carbon deposition, but this requires extra energy and is not economical.

Furthermore, it was experimentally confirmed that the catalyst used in this gasification method has excellent strength, abrasion resistance, water resistance, and gas resistance, and satisfies industrially required physical performance.

The first layer catalyst and the second layer catalyst may be packed in such a way that they are brought into close contact with the first layer and the second layer, respectively, or they may be separated from each other within a range that does not cause any adverse effects.

The distance between the two is preferably such that the time from leaving the first layer catalyst to reaching the second layer catalyst is within several seconds.

Note that the first layer and the second layer may be any combination of a fixed bed, a fluidized bed, and a moving bed.

It is also possible to perform steam reforming in the first layer and partial oxidation in the second layer.

The characteristics of gasification using the above-mentioned two-layer catalyst packing method are as follows: First, higher hydrocarbons are converted into CH, C2H using the first layer catalyst upstream of the reaction zone.
4, into lower hydrocarbons such as C3H6, and thoroughly decompose and gasify the hydrocarbons using the second layer catalyst downstream.

Note that it is not preferable to use the second layer catalyst alone because some carbon will be deposited on the catalyst.

The present invention provides the following significant advantages.

(1) Since the yield of H2 and CO is higher than when heavy oil is catalytically gasified using only the first layer catalyst, it is advantageous as a raw material for synthesis gas such as ammonia and methanol.

(2) Since the content of methane is extremely low, when it is used as a raw material for ammonia and methanol synthesis, the recycling load around the methane synthesis tube, which is an inert component, is reduced, which helps reduce power costs and downsize the equipment capacity. Economically advantageous.

(3) The load on separating methane from H2 and CO is reduced,
This results in a reduction in equipment costs and energy requirements.

With this gasification method, the drawbacks of the catalytic gasification method are significantly improved as described above, and the inherent advantages of the catalytic gasification method compared to the non-catalytic method can be specifically utilized.

That is, water droplets have (1) a reaction temperature of 200°C to 60°C;
Since the temperature is 0°C lower, the gasification efficiency is high and the yield of H2 and CO is high.

(2) Less amount of expensive oxygen is used.

(3) The life of the heat-resistant material constituting the reactor is long, and there is no need to use high-quality heat-resistant materials.

(4) The use of a catalyst reduces the amount of carbon deposited, and the amount of H
2. Since the yield of CO is high, it is advantageous as a raw material for synthesis gas, and at the same time, it is possible to downsize carbon recovery equipment and is economical.

The reaction conditions for carrying out the present invention are as follows.

The reaction temperature is 800°C or higher, especially 900°C to 1100°C.
is preferred.

If the reaction temperature is below 800° C., the catalyst layer 1 and carbon will precipitate, and the catalyst layer will become clogged, making continuous operation impossible.

The water vapor ratio (water vapor mole/carbon mole) is preferably 0.3 or more, particularly 0.3 to 7.

If the water vapor ratio is lower than this, carbon will precipitate in the catalyst layer, and if the water vapor ratio is increased further than this, it will be uneconomical.

The gasification pressure is preferably normal pressure to 100 kg/cyr*, and the reaction zone residence time is preferably 0.1 to 10 seconds.

The oxygen-containing gas used in gasification by partial oxidation includes air, oxygen, and a mixed gas of air and oxygen in any proportion.

The chromium oxide-containing catalyst used in the present invention has a chromium oxide content of 50 to 100% by weight.

Hydrocarbon decomposition activity is substantially due to chromium oxide, but aluminum oxide, zirconium oxide, alkaline earth metal oxides, One or more of nickel and cobalt oxide may be mixed, but if the chromium oxide content is less than 50% by weight, the amount of methane remaining will increase and the economic efficiency of the entire process will decrease.

The preferred filling ratio of the first layer catalyst and the second layer catalyst varies depending on the residence time in the catalyst layer, so it cannot be determined unconditionally, but the higher the filling ratio of the second layer catalyst, the higher the hydrocarbon decomposition activity. , the residual methane content in the produced gas decreases, but
If the first layer catalyst is extremely reduced, higher hydrocarbons
Since the carbon comes into contact with the second layer catalyst without being sufficiently converted into lower hydrocarbons such as H4, C2H4°C3H6, etc., carbon is deposited on the second layer catalyst.

In the case of a superficial velocity of 200 hr' based on the produced gas at normal pressure, if the filling ratio of the second layer catalyst exceeds 90 volume, a small amount of carbon will be deposited on this catalyst, and if it is less than 25 volume %, the amount of methane remaining will be small. Therefore, the preferred filling ratio of the second layer catalyst is 30 to 80% by volume.

Next, in order to make the present invention easier to understand, catalyst production examples and reaction examples are shown, but the technical scope of the present invention is not limited only to these examples.

First layer catalyst production example (A catalyst) 643 parts of alumina cement (composition A120380%,
476 parts of calcium hydroxide was mixed with Ca019.5%), molded, baked at 1300°C for 2 hours, and then crushed.
Wheat flour and a CMC solution with a concentration of 1.5% were added to this powder in advance by 5 weights and 15 weights of the powder amount, and kneaded.
Molded into a tablet shape with a height of 10 mm and a height of 1330 mm.
It was prepared by baking at ℃ for 6 hours.

This calcium aluminate catalyst has a compressive strength of 350 kg.
/CrIL and has good water resistance.

As a result of X-ray diffraction of this catalyst, the main component was 12Ca04A1203, with some 3Ca0.
7A1203 was recognized.

1st layer catalyst production example (Catalysts B and C) 1 molecular weight of potassium carbonate and 6 molecular weight of aluminum hydroxide are mixed and molded, baked at 1500°C for 1 hour and then crushed, sawdust is added to this powder, and the concentration is 1.5 % CMC solution was added in an amount of 5% by weight and 15% by weight of the powder amount, respectively, and kneaded to obtain a diameter of 10%.
1500 pieces molded into a dragon tablet with a height of 10 dragons
C. for 6 hours to prepare catalyst B.

Catalyst C was prepared from sodium carbonate and aluminum hydroxide in a similar manner.

These alkali aluminate catalysts have a compressive strength of 300 kg/
cut, and the water resistance was also good.

As a result of linear diffraction, the main component was RA1508, with a small amount of R2A124037.

(R represents K or Na) First layer catalyst production example (M catalyst) 10 parts of nickel oxide and 31 parts of tungsten oxide are mixed and molded, fired at 1300°C for 2 hours, then crushed. A CMC solution with a concentration of 1.5% by weight was added to the powder by 5% of the amount of powder, and the mixture was kneaded, formed into a tablet with a diameter of 10mm and a height of 10mm, and baked at 1300°C for 6 hours. .

The compressive strength of this catalyst is over 300 kg/cyyf,
Water resistance is also good.

2nd layer catalyst production example (Catalyst D) A CMC solution with a concentration of 1.8% by weight is added to 100 parts of chromium oxide and 1.5% by weight is added to the chromium oxide, and the mixture is kneaded with a diameter of 10 m.
7n was molded into a tablet with a height of 10 mm, and 1300
It was prepared by baking at ℃ for 3 hours.

This catalyst had good water resistance, but the compressive strength was 100
~200 kg/cyyt, and although some powdering was observed during handling, it was durable for use.

2nd layer catalyst production example (Catalyst E) 97 parts of chromium oxide and 3 parts of magnesium oxide were mixed well, and 15 weight of this powder was added and kneaded with a CMC solution with a concentration of 1.8 weight. It was prepared by compressing into tablets of 1011 trft and baking at 1300° C. for 3 hours.

This catalyst has good water resistance and compressive strength of 450 kg.
/cI? L, the powdering during handling was also significantly improved compared to the catalyst.

Second layer catalyst production example (F, G, H, 1, J, and the following various catalysts were prepared in the same manner as the L catalyst (E catalyst).

Example 1 In partial oxidation of claate atmospheric residue oil with oxygen,
The gasification results are shown below when catalyst A and catalyst B are used alone, and when catalyst A and catalyst E are packed in the first layer and E catalyst in various ratios in the first layer and the second layer in the reaction tube, respectively, in accordance with the gist of the present invention. It is shown in Table 1.

As is clear from the table, by packing both catalysts A and E in two layers, it was found that the residual methane in the produced gas was significantly reduced, and that there was a preferable range for the filling ratio of both catalysts A and E. Ta.

Example 2 Catalyst A was placed in the first layer of the reaction tube, and catalyst F was placed in the second layer.
Table 2 shows the results of partially oxidizing claate atmospheric residual oil with oxygen by filling G, H, 1, and J with various catalysts of L.

In either case, no carbon precipitation was observed in the catalyst layer.

Example 3 The first layer of a reaction tube was filled with 25% by volume of catalyst A or B, and the second layer was filled with 75% by volume of catalyst E, and claate crude oil, normal pressure residual oil, and vacuum residual oil were continuously brought into contact under various reaction conditions. The gasification results are shown in Table 3.

In all cases, the amount of methane remaining in the produced gas was extremely small, and no carbon precipitation was observed on the catalyst layer.

Example 4 When using M catalyst alone and in the first layer in the reaction tube
Table 4 shows the results of partial oxidation and gasification of craate atmospheric residual oil with oxygen when the second layer was filled with 75 volumes of E catalyst.

Claims (1)

[Claims] 1 When heavy oil with a specific gravity of 0.8 or more is gasified by contact with steam or steam and oxygen-containing gas, 850 to 110
At a temperature of 0°C, it is first brought into contact with a gasification catalyst consisting of calcium aluminate, alkali aluminate or tungsten-containing nickel, and then a chromium oxide catalyst or chromium oxide is contacted with an alkaline earth metal oxide, aluminum oxide, zirconium oxide, A catalytic gasification method characterized by contacting with a catalyst made of a mixture of one or more of nickel oxide and cobalt oxide.