KR810000451B1 - Emulsion catalyst for hydrogenation processes - Google Patents

Abstract

The title process involves the hydrogenation of a mixt. of pulverized coal and recycle oil (derived in the operation) in the presence of H and a catalyst consisting of an emulsified mixt. of H2O and a compd. such as (NH4)6Mo7O24. Other metal compds.(Fe, Co, Ni, Zn, etc.) are suggested.

Description

Hydrogenated Hydrocarbons with Emulsion Catalyst

The present invention relates to a method for hydrogenating a hydrocarbon material with an emulsion catalyst, wherein the hydrogenation catalyst is conveniently dispersed and contacted in the reaction mixture in an efficient manner. In particular, it relates to an improved process for dispersing such catalysts in heavy petroleum fraction of coal and in liquid hydrocarbon slurry of coal before hydrogenation.

The process of hydrogenating residue oil pulverized coal or other heavy hydrocarbons to obtain gas and liquid mixtures has been studied for many years. Recently, the liquefaction of coal has become an urgent task, especially due to the reduction of petroleum resources.

Coal can be successfully hydrogenated to produce gas and liquid products without the use of a hydrogenation catalyst, but is generally due to the amount of catalytically active metal present in the coal. More preferred products are obtained under suitable reaction conditions using a metal hydrogenation catalyst.

Effective catalysts for use in the process are known which use metals alone or in combination, for example, iron, nickel, cobalt, molybdenum, tungsten, tin, zinc, vanadium, chromium, antimony and other metal compounds. Metals such as palladium, platinum and rhenium are also effective for this purpose but are too expensive. Such hydrogenation catalysts may be added to the hydrogenation mixture either as micronized metals or as supported or unsupported compounds thereof. Most of these metal catalyst types having excellent stability in the hydrogenation of coal and heavy petroleum fractions are sulfides or sulfides pre-vulcanized to form sulfides or catalysts during the hydrogenation process from sulfur naturally present in fossil hydrocarbons.

In two production processes using a special catalyst bed, usually nickel or cobalt molybdate supported on alumina, this catalyst bed allows a mixture of pulverized coal dispersions or heavy hydrocarbon bases in hydrogen and liquid hydrocarbon media at elevated temperatures and pressures. Pump. In the U.S. Bureau of mine, the process of developing coal hydrogenation uses small or fine, fixed-bed catalysts. This process was revealed by Jaborsk, et al. (Chem Eng Progress 69 (3), 51-2 (1973)). In a fluidized bed or H-coal process, a similar phase catalyst is used, but finely ground, in which the reaction mixture continues to vibrate or boil, so that the reaction mixture reaches maximum contact with the catalyst particles. Use catalyst. This process has been used for hydrogenation of coal and hydrogenation of residual oils. Both of these methods are effective for this purpose but have several difficulties and disadvantages associated with the use of phase catalysts. In other words, a specially designed device is required, the absorption of catalyst by feedstock should be avoided, cake or plugging by catalyst particles generated in the production equipment should be avoided, the loss of effectiveness of catalyst by feedstock components, and a new catalyst in the reactor. Problems such as the addition of the catalyst, removal of the catalyst after use, and the like. Loss of fine catalyst in the produced oil is another problem of this process.

Other known coal and residual oil hydrogenation methods are catalysts or finely divided metals or metal compounds that are added directly to the reaction mixture and converted under reaction conditions to form a catalytically effective form. Some methods use metal hydrogenation catalysts in the form of water-soluble salts, with or without water. Schumann uses a liquid medium in coal slurries containing, in part or whole, water containing catalysts of metal salts in solution, ie ammonium heptamolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O), in US Pat. No. 3,745,108. did. The latter method is effective, but it limits the manufacturing conditions and equipment since the liquid aqueous phase must be maintained. This method therefore requires lower temperatures, resulting in lower conversion of coal and lower yield of liquid hydrocarbons. The more effective use of catalysts for the hydrogenation of coal is the pre-applied catalytic compound to coal.

In contacting a hydrocarbon substrate with hydrogen in the presence of a metal-containing hydrogenation catalyst in a water immiscible phase, the metal-containing catalyst is initially added to the water-immiscible liquid in an aqueous solution emulsion state. All the drawbacks involved in the method have been solved. The metal compound is converted under hydrogenation conditions to obtain an effective hydrogenation catalyst. Catalysts effective in this way are produced in situ as extremely fine particles that are uniformly dispersed in the liquid reaction mixture.

Under these hydrogenation process conditions, the dissolved metal compound, which is no longer separated from the water-soluble phase, is decomposed and converted into an effective form as a metal catalyst, that is, an emulsion.

Thus, the present invention is an improved process that makes it easier and more efficient to disperse the catalyst and to achieve maximum effect in very small amounts.

This method of adding and dispersing a catalyst in the reaction mixture is more effective and lower boiling point by hydrogenating coal, heavy petroleum fraction, residual oil and leading edge, or heavy hydrocarbons such as tar or pitch derived from petroleum or coal. There is an advantage of obtaining a product, gas or liquid (typically large amounts of liquid product are preferred). The conditions for hydrogenating such materials are well known. In the reaction conditions, the pressure ranges from 1000 psi (71 kg / cm 2) to 1000 psi (710 g / cm 2), but usually 1500 to 3000 psi (105 to 212 kg / cm 2), and the temperature is 300 ° C. to 600 ° C., but is usually a catalyst or hydrogenated substance. The temperature of 400 ° C to 500 ° C is used depending on the type of the product, the type of the desired product (e.g., a large or small amount of gaseous hydrocarbon low boiling liquid or relatively high boiling liquid hydrocarbon).

This new method has particular advantages in liquefying coal, in particular in coal grinding and dispersing in liquid hydrocarbon medium to provide a pumpable slurry.

Catalysts used in the form of water-soluble salts are selected from metals such as iron, cobalt, nickel, molybdenum, tungsten, tin, zinc, vanadium, chromium and antimony. Since the amount of catalyst used in this improved process is well dispersed in the reaction mixture, an amount smaller than the amount preferably used in a similar known method can be used. Molybdenum is obtained in the form of ammonium or alkali metal heptamolybdate, using molybdenum in a ratio of 0.01 to 1% based on coal or other hydrogenated material. Molybdenum is about 0.02 to 0.5 Percentages are preferred, which is comparable to the effect obtained with known processes which typically use more catalyst. The improved method is also effective when small amounts of hydrogenation catalysts are used for other coals and residual oils.

Lower activity catalysts, such as iron, require somewhat higher proportions, eg up to 1%. Catalyst proportions in the reaction mixtures vary, which affects the distribution and conversion of the product. In general, relatively higher conversions can be obtained with the use of catalysts at higher rates, but unwanted gases and gas oils are obtained together in high yields. According to the present invention, which disperses the catalyst well, it is possible to use a small proportion of the catalyst, thereby obtaining high conversion and high yield of high boiling oil. The convenient way of adding the catalyst and the wide range of applications are another major advantage of the present invention.

The ratio of the metal compound to the water and the ratio of the aqueous solution to the emulsion oil have an important effect on the characteristics of the catalyst. Emulsifying the concentrated aqueous solution yields good results, but generally produces a more effective catalyst because smaller particles of the catalyst are produced when using relatively diluted solutions. It is desirable to add a high proportion of emulsion oil to the aqueous solution in order to produce a relatively stable emulsion of droplets and a finely dispersed catalyst. Usually, the liquid feed mixture is passed through the hydrogenation process immediately after the emulsion catalyst solution is made, so the emulsion does not have to have very high stability. Thus, the use of emulsions or emulsion stabilizers is also unnecessary. In some cases, however, this addition may be beneficial to catalyze emulsion formation or to obtain very small droplets in the emulsion. Another convenient method may be used to emulsify the salt solution in a hydrocarbon medium. The particle size of the water-soluble phase in the emulsion must be very small in order to obtain the catalyst dispersed in the entire reaction mixture. The above conditions can be achieved by first forming a dispersion of the oil in the aqueous solution and inverting the dispersion, then gradually adding more oil so that the oil continues to be in the aqueous phase and the aqueous solution is dispersed very finely therein. However, other methods can be used to form the emulsion and satisfactory results can be obtained.

In the coal and residual oil hydrogenation methods, separate vulcanization steps are also used to make metal catalysts more effective.

In this improved process, a small amount of catalyst becomes effective sulfide effectively during operation due to the small amount of sulfur present in coal and petroleum. Thus, no special vulcanization process of the catalyst is required.

Slurry powdered or dispersed (if dilution is preferred) liquid hydrocarbon medium in residual oil or tar may be a suitable petroleum fraction or similar liquid hydrocarbon, but is preferably hydrogenated as used in most known hydrogenation methods. Liquid hydrocarbon water is obtained from the process or recycle oil fraction.

In order to get a very good product, this recirculating oil is treated to remove at least low temperature substances and insoluble components. In the liquefaction of coal, sufficient amount of oil is added to the coal during the slurry process to obtain a pumpable mixture as shown in the general art.

Typical oil to coal ratios are 55 to 75 parts to 45 to 25 parts by weight. In the hydrogenation of residual oil, tar or pitch, it is preferable to add a liquid hydrocarbon medium in a small amount or not at all.

If the salt of the metal used as a catalyst is water-soluble, any salt can be killed. Metal catalysts such as iron group, tin or zinc are most suitable for nitrates or acetates, but molybdenum, tungsten or vanadium are more preferably complex salts such as alkali metal or ammonium molybdate, tungstate or vanadate. Two or more metal salts may be mixed and used.

The advantage of this method is that it uses a very small amount of catalyst and therefore does not require a catalyst recovery process as in many known methods.

Another advantage of this method is that there is no need to increase the circulation speed inside the reactor or costly downtime to remove the catalyst deposited in the production apparatus by using a small amount of catalyst and by highly dispersing the catalyst. The reactor facility is simple.

Main course

The analysis method used in the following Example is as follows.

Viscosity :

The viscosity of the sample oil was measured at 25 ° C. using a Brookfield viscometer. Ash was not removed from the oil before the measurement.

Insoluble Matter and Ash in Toluene

40 g of the sample is shaken with 160 g of toluene and centrifuged.

The supernatant is decanted and the residue and ash of toluene insoluble hydrocarbons are vacuum dried at 100 ° C. to be weighed. The moisture content of the residue is measured by standard methods.

Asphaltene

25 g sample is shaken with 100 g n-hexane and centrifuged. The supernatant is decanted and the residue, i.e., a mixture of toluene soluble hydrocarbons insoluble in toluene insoluble substance n-hexanesphaltene, is vacuum-dried at 100 deg. The asphaltene content is the value of toluene insolubles and ash minus total hexane insolubles.

Coal analysis

The coal used in this example was ground and ground in a Pittsburgh No. 8 Alllsion mine, dried and then ground to pass through a 120 mesh sieve (U.S. Sieve Series). The sulfur content was about 3.9%.

Example 1

In a 55- (US) gallon (208 liter) tank containing 73 Lb (33.2 kg) of bituminous coal, the particle size was crushed to 75 mμ or less, dried and 109.5 Lb (49.5 kg) of circulating oil obtained during the hydrogenation process of coal until a slurry was obtained. ) Is added and stirred.

The following emulsion catalyst solution (ammonium heptamolybdate tetrahydrate, (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O) was added to the slurry and dissolved by adding 109.5 g of water at room temperature. The emulsion in oil is prepared by slowly adding 350 g of filtered recycled oil to the solution over 5 minutes with stirring.

This catalyst emulsion is added to a slurry of coal in oil and the mixture is stirred for one hour. The coal oil slurry was fed by a high pressure pump to the point where it was mixed with hydrogen and under a pressure of 2000 psi (140 kg / cm ₂ ) through a long cylindrical reactor with a volume of 0.286 cuft (8.1 l) maintained at 460 ° C. in the preheater and temperature. It is fed in slurry 13.6 Lb (6.04 kg) and H ₂ 0.265 Lb-mol (0.117 kg-mole) per hour.

The effluent from the reactor is lowered to atmospheric pressure and separated by a conventional method to obtain a gas, a light oil having a boiling point of 150 ° C. or lower, a small amount of water-soluble phase and an oil having a boiling point of 150 ° C. or higher in addition to the residue. The distribution ratio of the product based on the supplied slurry is as follows.

TABLE 1

Based on the supplied slurry, the hydrogen conversion is at least 50% and the total recovery of the product is at least 98%.

Example 2

A two-step experiment was conducted to demonstrate the effect of the suspended catalyst system on the hydrogenation of coal using the apparatus and method described in Example 1. In a first stage lasting 28.75 hours, 40 wt% coal-60 wt% recirculating oil slurry was charged with 21.4 Lb (9.7 kg) slurry and hydrogen per hour under the temperature and pressure of the reactor as in Example 1 without adding a catalyst. Pump through the reactor at an average rate of 0.35 Lb-mole (0.16 kgmole). The recycle oil contains 70 ppm Mo (corresponding to 0.01% Mo based on coal) remaining in the operation.

In the last step of the first step, an emulsion of water-soluble ammonium molybdate in oil is added to the supplied slurry to obtain Mo with a content of 0.12% based on coal. This slurry mixture is run through a reactor as above for 8.7 hours.

Samples of the effluent are taken for analysis at various points during the two-step reaction operation and a large volume of effluent is collected for equilibrium measurements, once in the second and second time.

The recycle oil is the product having the following analysis at 150 + ° C.

TABLE 2

The coal used here has an average ash content of 11.7%.

TABLE 3

Analytical Sample

TABLE 4

Equilibrium Samples

The conversion percentage of coal is calculated by the following equation.

% Conversion =

In the above formula

S = weight fraction of coal in slurry

X ₁ = oil fraction of toluene insolubles in slurry oil

Fraction of ash in Y ₁ = X ₁

Y ₂ = fraction of ash in coal

Fraction of ash in toluene insolubles from Y ₃ = 150 + ° C

X ₃ = 150 + ° C Oil fraction of toluene insolubles

h = H ₂ Lb (2.2 kg) consumed per Lb of coal (2.2 kg)

Ash of product as Z = 150 + ° C. oil.

Example 3-7

60-40 oil-coal slurry containing various metal salt solutions suspended in oil is pumped through the reactor at 460 ° C., 2000 psi (140 kg / cm 2) using the apparatus and method described in Example 1.

The catalyst salts in Examples 3 and 4 were 0.11% similar Ni (NO ₃ ) ₂ 6H ₂ with 0.11% (based on coal) Co (NO ₃ ) ₂ 6H ₂ O and ammonium heptamolybdate tetrahydrate mixtures, respectively. O and ammonium heptamolybdate tetrahydrate mixtures in which the metals are present in the same atomic ratio.

In Example 5 the catalyst salt was 0.5% FeSO ₄ 7H ₂ O, in Example 6 the catalyst salt was 0.1% Na ₂ WO ₄ 2H ₂ O, and in Example 7, the catalyst salt was 0.11% ammonium as in Example 1. Um heptamolybdate tetrahydrate.

Samples of the effluent are in each case analyzed after several hours of operation as above. The conditions and measurement results are described in Table 5.

TABLE 5

Example 8

As in the above embodiment, 60 to 40 recycle oil-coal slurry was subjected to hydrogen 0.36 Lb-mole (0.163) at a constant rate of 20 Lb / hr (9.1 kg / hr) per hour under a pressure of 2000 psi (140 kg / cm ₂ ). kg / mole) is pumped through the reactor. The fed coal slurry contains ammonium heptamolybdate solution suspended at a concentration of 0.027% molybdenum based on coal. At this time, the temperature controller of the reactor is fixed at 475 ° C. As shown in the results of Table 4, the proportions of gas, diesel, water and toluene insolubles are higher at higher temperatures while the asphaltene content and viscosity of the 150 + ° C oil fractions are lower.

TABLE 6

In a similar manner as shown in the above examples, a solution in a hydrocarbon oil containing an emulsion of a metal catalyst salt or a dispersion of residual oil, tar or pitch is hydrogenated to obtain a low boiling hydrocarbon product. Since the viscosity of the residual oil or other fractions is very low, it is not necessary to add light oil as a diluent. The oil fraction itself, of course, consists of a liquid medium. As indicated above, the production rate of gas and low-boiling liquid hydrocarbons in the product is increased when using a high temperature, a long time and some high proportion of the catalyst.

As can be seen above, the process of adding and dispersing the hydrogenation catalyst as the water-soluble metal compound emulsion in the liquid reaction mixture described herein can be similarly used in other hydrogenation processes.

This process, for example, hydrogenation of benzene and naphthalene to give cycloparaffins and hydrogenation of animal and plant oils to obtain saturated fats.

Claims (1)

The hydrocarbon material is a water immiscible phase, the metal-containing hydrogenation catalyst in contact with hydrogen in the presence of a metal-containing hydrogenation catalyst of iron, cobalt, nickel, molybdenum, tungsten, tin, zinc, vanadium, chromium or antimony. Is initially added to the water immiscible liquid phase in the form of an emulsion of an aqueous solution.