Process for thermal cracking of carbonaceous substances which increases gasoline fraction and light oil conversions

A process for thermally cracking carbonaceous substances, such as coal, is described, comprising: rapidly heating the carbonaceous substance to 500.degree. to 950.degree. C. in an atmosphere consisting essentially of hydrogen gas at a pressure of 35 to 250 kg/cm.sup.2 (gauge pressure) in the presence of at least one compound selected from the group consisting of halides, sulfates, nitrates, phosphates, carbonates, hydroxides, and oxides of Group VIII metal elements of the Periodic Table. The process increases the cracking of the carbonaceous substances and accelerates the conversion of the carbonaceous substances into gas and liquid products, greatly increasing the yields of the gasoline fraction and light oils.

FIELD OF THE INVENTION 
The present invention relates to a process for thermally cracking 
carbonaceous substances in the presence of hydrogen to produce gases and 
liquid oils directly from the carbonaceous substances. More particularly, 
the present invention relates to a novel thermal cracking process which 
increases the cracking of carbonaceous substances, accelerates the 
conversion of the carbonaceous substances into gas and liquid products, 
and increases the yields of gasoline and light oil fractions. 
BACKGROUND OF THE INVENTION 
Recently, in view of the exhaustion of oil resources in the future, the 
usefulness primitive carbonaceous substances, such as coal and tar sand, 
which are now the most abundant fossil fuel sources and widely distributed 
all over the world have been reconsidered. These substances have received 
increasing attention as an energy source and a chemical feed capable of 
replacing petroleum. However, coal is a very complicated polymeric 
compound, and contains fairly large amounts of hetero atoms, such as 
oxygen, nitrogen, and sulfur, and ash, as well as carbon and hydrogen 
which are the major constitutive elements. Therefore, coal, when burned as 
such, produces large amounts of air pollution substances. Furthermore, 
coal is not desirable because its calorific value is low as compared with 
petroleum, and the transportation and storage of coal is cumbersome and 
expensive. 
In order to overcome the above-described substantial problems of coal, a 
number of methods of liquifying coal have been proposed in which the coal 
is liquified to remove the hetero atoms and ash, and to produce fuel oils 
or gases causing no air pollution as well as chemical starting materials 
of high practical value. Typical examples include a method in which coal 
is extracted with a solvent (see U.S. Pat. No. 4,022,680), a method in 
which coal is liquified in the presence of hydrogen or a hydrogen-donating 
compound (see U.S. Pat. No. 4,191,629 and W. German Pat. No. 2,756,976), a 
method in which coal is liquified and gassified in the presence of 
hydrogen (see U.S. Pat Nos. 3,152,063, 3,823,084, 3,960,700, 4,169,128, 
3,985,519 and 3,923,635), and a method in which coal is liquified and 
gassified in an inert gas (see U.S. Pat. No. 3,736,233). 
In accordance with these methods, however, it is not possible to mainly and 
efficiently produce a gasoline fraction which is to be used as a fuel for 
transportation and a chemical feedstock, although the methods can directly 
produce those ingredients which can be used as an energy source. 
A method of directly producing a gasoline fraction which has been known 
involves injecting finely ground coal in a high temperature and pressure 
hydrogen stream to achieve high-speed hydrogenation and thermal cracking 
of the coal in a short period of time of from several ten milliseconds to 
several minutes. More specifically the finely ground coal is injected into 
a hydrogen stream having a pressure of from 50 to 250 kg/cm.sup.2 (gauge 
pressure) and a temperature of from 600.degree. to 1,200.degree. C. The 
coal is heated rapidly at a rate of from 10.sup.2 to 10.sup.3 .degree. 
C./sec to achieve the hydrogenation and thermal cracking. This method 
produces gas products such as methane, ethane, carbon monooxide, carbon 
dioxide, steam, hydrogen sulfide and ammonia, liquid products such as a 
gasoline fraction and heavy oil (comprising aromatic compounds containing 
at least 10 carbon atoms and high boiling tar), and a solid product 
containing ash, which is called "char". 
This method, however, has various disadvantages. For example, when the 
reaction temperature is lowered, the total conversion of coal into liquid 
or gas is decreased, the total conversion being given by the following 
formula: 
##EQU1## 
Furthermore, heavy oils such as aromatic compounds containing at least 10 
carbon atoms and tar are produced as main products. On the other hand, 
when the reaction temperature is raised, although the total conversion is 
increased, decomposition of liquid products is accelerated, resulting in 
the production of methane as a main product. This leads to a reduction in 
the gasoline fraction conversion; i.e., the conversion is at most from 3 
to 8%. 
As a result of extensive studies on the production of the gasoline fraction 
to be used as a fuel for transportation or a chemical feedstock from 
carbonaceous substances, such as coal, in high yield, it has been found 
that: 
(1) the gasoline fraction is produced not only directly from the 
carbonaceous substances, but also from liquid products, intermediate 
products produced in the course of thermal cracking, which are further 
hydrocracked and converted into lighter products; 
(2) the proportion of the gasoline fraction produced from the liquid 
products in the total gasoline fraction is much greater than that of the 
gasoline fraction produced directly from the carbonaceous substances; 
(3) therefore, in order to increase the conversion of the carbonaceous 
substances into the gasoline fraction, it is necessary to increase the 
amount of the liquid products, i.e., gasoline fraction precursors, being 
formed; and 
(4) when the carbonaceous substances are thermally cracked in the presence 
of certain kinds of metal compounds, the thermal cracking is accelerated, 
and the conversion of the carbonaceous substances into the liquid products 
is increased. 
Furthermore, it has been found that not only the conversion of the 
carbonaceous substances into the gasoline fraction is increased, but also 
the conversion of the carbonaceous substances into light oils is greatly 
increased. The term "light oil" as used herein refers to an oil composed 
mainly of from 2 to 5 ring-condensed aromatic compounds. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a novel thermal cracking process 
which increases decomposition of carbonaceous substances and accelerates 
the conversion of the carbonaceous substances into liquid products and 
gases, making it possible to produce a gasoline fraction directly from the 
carbonaceous substances in high yield. 
The present invention relates to: 
(1) a process for thermally cracking a carbonaceous substance which 
comprises heating the carbonaceous substance rapidly to a temperature of 
from 500.degree. to 950.degree. C. in an atmosphere essentially consisting 
of hydrogen gas of pressure of from 35 to 250 kg/cm.sup.2 (gauge pressure) 
in the presence of at least one compound selected from the group 
consisting of halides, sulfates, nitrates, phosphates, carbonates, 
hydroxides and oxides of Group VIII metal elements of the Periodic Table; 
and 
(2) a process for thermally cracking a carbonaceous substance which 
comprises heating the carbonaceous substance rapidly to a temperature of 
from 500.degree. to 900.degree. C. in atmosphere consisting essentially of 
hydrogen gas of pressure of from 35 to 250 kg/cm.sup.2 (gauge pressure) in 
the presence of at least one compound selected from the group consisting 
of halides, sulfates, nitrates, phosphates, carbonates, hydroxides and 
oxides of Group VIII metal elements of the Periodic Table, and then, 
cracking the above-thermally cracked carbonaceous substance at a 
temperature higher than the above temperature, but falling within the 
range of from 600.degree. to 950.degree. C.

DETAILED DESCRIPTION OF THE INVENTION 
The Group VIII metal elements of the Periodic Table as used herein include 
Fe, Co, Ni, Ru, Rh, Pd and Pt. Of these metal elements, Fe, Co and Ni are 
preferred, because the compounds of Fe, Co and Ni such as iron sulfate, 
nickel sulfate, iron hydroxide and nickel hydroxide increase the rapid 
thermal cracking rate of the carbonaceous substance. This causes an 
increase in the conversion of the carbonaceous substance into a gasoline 
fraction and light oil. Further, the Fe, Co and Ni compounds are readily 
available, and therefore, are advantageous for use in the industrial 
practice of the process of the invention. 
Any of the compounds of the Group VIII metal elements of the Periodic Table 
can be used to attain the objects of the invention. These compounds 
increase the total conversion of the carbonaceous substance by thermal 
cracking, increase the conversion of the carbonaceous substance into the 
gasoline fraction and light oil, and at the same time, decrease the 
cracking temperature. The type of the metal compounds used can be 
determined appropriately depending on the type of carbonaceous substance 
to be thermally cracked. Of these compounds, the halides, sulfates, 
nitrates, phosphates, carbonates and hydroxides are preferably used in the 
process of the invention. They are preferred because they increase the 
conversion of the carbonaceous substance into the gasoline fraction and 
light oil. For example, iron sulfate, nickel sulfate and nickel hydroxide 
are preferably used for the thermal cracking of brown coal, and iron 
hydroxide, iron nitrate and cobalt carbonate in addition to the above 
compounds are preferably used for the thermal cracking of bituminous coal 
and sub-bituminous coal. In particular, the sulfates, nitrates, carbonates 
and hydroxides are more advantageous since they increase the conversion of 
the carbonaceous substance into the gasoline fraction, and cause less 
corrosion of reaction equipment. When using those compounds the 
requirement generally requires no treatment to prevent corrosion. 
Any compounds which are usually called carbonates can be used as the 
carbonates of the invention including basic carbonates. 
In the process of the invention, the above-described metal compounds can be 
used alone or in combination with each other. In order to efficiently 
increase the conversion of the carbonaceous substance into the gas and 
liquid products, it is preferred that the metal compound is previously 
mixed with the carbonaceous substance. The resulting mixture is then 
introduced into a reactor, even though the metal compound and the 
carbonaceous substance can be fed separately to the reactor. The metal 
compound and the carbonaceous substance can be mixed by any suitable 
technique. For example, they are finely ground, and mechanically mixed by 
the use of, e.g., a mortor, a ball mill, a V-shaped powder mixer and a 
stirring mixer, or the metal compound is first dissolved or suspended in 
water or an organic solvent such as alcohol and the coal is then added to 
the resulting solution or suspension and dipped therein and finally the 
solvent is removed. 
In mixing the hydroxide or carbonate with the carbonaceous substance, there 
can be used a process in which the halide, sulfate, nitrate or the like of 
the same metal element is dissolved in water or an organic solvent such as 
alcohol, followed by adding alkali hydroxide such as potassium hydroxide 
and sodium hydroxide, ammonia water or alkali carbonate to the resulting 
solution with stirring to form the corresponding hydroxide or carbonate. 
Coal is then added to the solution to deposit thereon the hydroxide or 
carbonate, and the coal with the hydroxide or carbonate deposited thereon 
is filtered off. Of course, the coal may be added to a solvent together 
with, for example, the halide, sulfate, or nitrate, and then, mixed with 
alkali hydroxide, ammonia water, or alkali carbonate, filtered, and 
washed. 
This mixing process utilizing solvents is preferred in that the 
carbonaceous substance/metal compound mixture prepared using the solvents 
is superior in the dispersion and attaching properties of the metal 
compound onto the carbonaceous substance to the mechanically prepared 
mixture, and shows very high activity. 
The amount of the metal compound added can be determined appropriately and 
optionally depending on the type of the carbonaceous substance used. For 
instance, the thermal crackings of bituminous coal and sub-bituminous coal 
are preferably performed with a larger amount of the metal compound (1.2 
to 2 times larger) than that in the case of brown coal, and the thermal 
cracking of brown coal can be effectively performed even with a smaller 
amount of the Ni or Co compounds (e.g., 3/10 to 8/10 times smaller) than 
that of the Fe compounds. In general, the metal compound is added in an 
amount ranging from 0.0001 to 0.2 part by weight, preferably from 0.001 to 
0.1 part by weight, more preferably from 0.005 to 0.1 part by weight, per 
part by weight of the carbonaceous substance (not containing water and 
ash). In lesser amounts than 0.0001 part by weight, the total conversion 
and the conversion of the carbonaceous substance into the gasoline 
fraction and light oil are low. On the other hand, in greater amounts than 
0.2 part by weight, any further increase in the conversion is not 
obtained. Further, there is consumption of hydrogen due to the 
decomposition of the metal compound and the production of gases, liquid 
products and char, containing large amounts of S, N, P and halogen. This 
is undersirable and causes problems such as air pollution and corrosion of 
the reactor. In the thermal cracking of brown coal, the Ni compounds and 
the Fe compounds are preferably added in amounts of 0.005 to 0.05 part by 
weight and 0.01 to 0.1 part by weight, respectively, per part by weight of 
the carbonaceous substance. 
When the metal compounds are used as a mixture comprising two or more 
thereof, it is preferred that at least one of the compounds of Fe, Co and 
Ni are present within the range of from 0.0001 to 0.1 part by weight, 
particularly preferably from 0.001 to 0.1 part, per part by weight of the 
carbonaceous substance. 
The cracking temperature as used in the process of the invention is within 
the range of from 500.degree. to 950.degree. C. This temperature is higher 
than the temperatures at which the usual liquification processes utilizing 
solvents are performed, but lower than the temperatures as used in the 
usual gasification processes. The use of the metal compounds as described 
above makes it possible to obtain the maximum yield of the gasoline 
fraction within a temperature range about 20.degree. to 200.degree. C. 
lower than the thermal cracking temperature that is needed for the thermal 
cracking of the carbonaceous substance in the absence of the metal 
compounds. 
The thermal cracking temperature can be chosen appropriately within the 
above-described range depending on, for example, the characteristics such 
as type, viscosity and grain size, of the carbonaceous substance, heating 
time and the type of the metal compound used. For example, when the 
heating time is 7 seconds, the temperature is preferably from 600.degree. 
to 800.degree. C. for the thermal cracking of carbonaceous substances 
having a low degree of carbonation and from 700.degree. to 850.degree. C. 
for those having a high degree of carbonation. The term "high degree of 
carbonation" used herein means high carbon content, in other words low 
ratio of hydrogen content to carbon content. Further the thermal cracking 
can be performed within a relatively low temperature range using 
hydroxides or carbonates of the present invention. When the temperature is 
lower than 500.degree. C., the cracking is reduced, and the total 
conversion and the conversion of the carbonaceous substance into the 
gasoline fraction and light oil are decreased. On the other hand, when the 
temperature exceeds 950.degree. C., the cracking rates of the gasoline 
fraction and light oil seriously increase. This undesirably leads to a 
reduction in the yield of the gasoline fraction and an increased formation 
of gas comprised mainly of methane. 
The heating time is not critical and varies depending upon the types of the 
carbonaceous substance and the metal compound and the thermal cracking 
temperature. The time is usually from 0.02 to 60 seconds and preferably 
from 2 to 30 seconds. When it is too short, the liquid products are not 
converted into the gasoline fraction and light oils, and when it is too 
long, the formation of methane becomes remarkable. In particular, the 
gasoline fraction can be effectively produced for 2 to 15 seconds in the 
thermal cracking of brown coal or sub-bituminous coal at 650.degree. to 
800.degree. C. using the Fe compounds. 
It has further been found that the gasoline fraction can be produced in 
much larger amounts by rapidly heating the carbonaceous substance at a 
temperature of from 500.degree. to 900.degree. C. in the presence of the 
above-described metal compound to crack the carbonaceous substance and 
diffuse the volatile components from the solid matrix, and subsequently, 
by cracking the above-thermally cracked carbonaceous substance at a 
temperature higher than the above-described cracking temperature, but 
falling within the range of from 600.degree. to 950.degree. C. In the 
first step, relatively low molecular weight products can be effectively 
produced while minimizing the formation of char and gas, and the resulting 
low molecular weight products can be efficiently converted into the 
gasoline fraction in the second step. 
The optimum combination of the first cracking temperature (the cracking 
temperature of the carbonaceous substance at the first step) and the 
second cracking temperature (the cracking temperature of the carbonaceous 
substance at the second step) is determined appropriately depending on the 
type of the carbonaceous substance. In general, the difference between the 
first and second cracking temperatures is from 10.degree. to 150.degree. 
C. For coal having a low degree of carbonation such as brown coal and 
lignite, the first cracking temperature may be relatively low, and thus, 
the temperature difference tends to increase. 
The reaction time at the second cracking step is preferably from 1 to 60 
seconds, more preferably from 2 to 30 seconds. When the reaction time is 
shorter than 1 second, the conversion of the carbonaceous substance into 
the gasoline fraction proceeds only insufficiently, whereas when it is 
longer than 60 seconds, the possibility of decomposition of the gasoline 
fraction increases. For coal having a low degree of carbonation, the 
second cracking time is preferably short (2 to 15 seconds), whereas it is 
preferably long (5 to 30 seconds) for coal having a high degree of 
carbonation. 
The rate of heating of the carbonaceous substance in the process of the 
invention is preferably at least 100.degree. C./sec and more preferably at 
least 1,000.degree. C./sec so that the gasoline fraction and its 
precursor, liquid product, are efficiently produced. When the heating rate 
is increased, the cleavage of cross-linking bonds in the structure of the 
carbonaceous substance, which results in the formation of the gasoline 
fraction and its precursor, liquid product, occurs more preferentially. 
Therefore there is no upper limitation with respect to the heating rate. 
For the purpose of the present invention, however, it is particularly 
preferably within the range of 1,000.degree. to 10,000.degree. C./sec. 
The pressure of the atmosphere consisting essentially of hydrogen gas as 
used herein should be within the range of from 35 to 250 kg/cm.sup.2 
(gauge pressure), and preferably it is from 50 to 200 kg/cm.sup.2. The 
term "atmosphere consisting essentially of hydrogen gas" as used herein 
includes both an atmosphere consisting of pure hydrogen gas alone and an 
atmosphere composed mainly of hydrogen gas. For example, the atmosphere 
may contain up to about 30% by volume of inert gas, steam, carbon dioxide, 
carbon monoxide, methane, etc. While the use of pure hydrogen gas results 
in increase of the gasoline fraction and light oils, the mixed gas may be 
used with the advantage that the thermal cracking process is simplified 
since steps for separating and purifying hydrogen gas can be omitted. 
The pressure of the atmosphere consisting essentially of hydrogen gas is a 
particularly important condition in the practice of the process of the 
invention in view of its effect of preventing polycondensation of the 
active liquid compounds formed during the direct thermal cracking of the 
carbonaceous substance, and for the purpose of cracking the liquid 
compounds into the gasoline fraction. At the above-described second 
cracking step, higher pressures are more effective. However, even if the 
pressure is increased beyond a certain upper limit, no additional effect 
is obtained, and rather, increasing to such high pressures is economically 
disadvantageous because it increases the equipment cost. 
In the process of the invention, the weight ratio of hydrogen to the 
carbonaceous substance feed (anhydrous and ash-free basis) varies with the 
type of the carbonaceous substance and the desired composition of reaction 
products. In general, the weight ratio of hydrogen to the carbonaceous 
substance feed (anhydrous and ash-free basis) is sufficient to be from 
0.03/1 to 0.08/1. However, in order to accelerate the diffusion of liquid 
products from the carbonaceous substance and the diffusion of hydrogen 
into fine voids of the carbonaceous substance powder, to increase the 
conversion of the carbonaceous substance into the gasoline fraction and to 
prevent coking, it is preferred to feed the hydrogen excessively. An 
excess of hydrogen is separated from the reaction products from the 
carbonaceous substance, and returned to the reactor for re-use. For this 
reason, if the amount of hydrogen being fed is extremely increased, a 
greater amount of energy is needed for the separation/recycle process and 
heating. Furthermore, it is inevitably necessary to increase the size of 
equipment. This is disadvantageous from an economic standpoint. Thus, the 
weight ratio of hydrogen to the carbonaceous substance feed is preferably 
from 0.1/1 to 2.5/1 and more preferably from 0.12/1 to 2.0/1. 
Carbonaceous substances which can be used in the process of the invention 
include not only coals such as anthracite, bituminous coal, sub-bituminous 
coal, brown coal, lignite, peat and grass peat, but also oil shale, tar 
sand, organic wastes, plants such as wood, and crude oil. 
The process of the invention increases the cracking of the carbonaceous 
substances and accelerates the conversion of the carbonaceous substances 
into the gas and liquid products, greatly increasing the yields of the 
gasoline fraction and light oils. 
The following examples are given to illustrate the invention in greater 
detail. It is to be noted, however, that the examples are given by way of 
illustration and are not to be construed to limit the scope of the 
invention. 
The conversion of the carbonaceous substance into each reaction product is 
defined by the following formula: 
##EQU2## 
EXAMPLE 1 
Brown coal from Australia was finely pulverized and passed through a sieve 
of 100 mesh (JIS: Japanese Industrial Standard) to obtain finely ground 
coal. The elemental analytical values of the coal (anhydrous basis) are as 
shown in Table 1 below. 
TABLE 1 
______________________________________ 
Element Amount (% by weight) 
______________________________________ 
C 58.2 
H 4.6 
O 21.8 
N 0.7 
S 4.1 
Ash 10.6 
______________________________________ 
The finely ground coal (20 g) was added to 500 ml of distilled water in 
which 0.5 g of ferric chloride had previously been dissolved, and mixed 
and stirred for 30 minutes. The resulting mixture was heated at 75.degree. 
C. under a reduced pressure of 20 mmHg to remove almost all of the water, 
and there was obtained the finely ground coal with ferric chloride 
deposited thereon. The amount of water was 5 parts by weight per 100 parts 
by weight of the finely ground coal with the ferric chloride deposited 
thereon. 
The thus obtained finely ground coal (1 g) was introduced uniformly over a 
period of 1 minute into a reaction tube made of nickel-chromium-iron alloy 
(Incoloy 800: trademark) through which hydrogen gas was passed under the 
conditions of temperature of 730.degree. C. and hydrogen pressure of 70 
kg/cm.sup.2 (gauge pressure). The residence time of the hydrogen gas 
passing through the heated reaction zone; i.e., the reaction time, was 7 
seconds, and the weight ratio of the hydrogen fed for the reaction to the 
coal feed was 1.8/1. Of the reaction products from the reaction tube, char 
was separated in a char trap, a gasoline fraction and heavy oil were 
condensed and separated in an indirect cooler using a coolant of 
-68.degree. C., and gases were reduced in pressure, collected in a 
sampling vessel, and analyzed. 
On basis of the analytical results, the conversion of the coal into each 
product was calculated, and the results are shown in Table 2. In Table 2, 
ethylene is 5% of ethane, and the total of ethane and ethylene is called 
ethane. 
EXAMPLES 2 TO 5 
The procedure of Example 1 was repeated wherein the type of the metal 
compound to be added and the reaction temperature were changed as follows: 
______________________________________ 
Type of Reaction 
Example Metal Compound 
Temperature 
______________________________________ 
2 Ferrous sulfate 
740.degree. C. 
3 Nickel sulfate 
745.degree. C. 
4 Cobalt phosphate 
760.degree. C. 
5 Palladium chloride 
775.degree. C. 
______________________________________ 
In the case of cobalt phosphate (Example 4), however, it was finely ground 
to a grain size of 50 .mu.m or less, and mixed with the finely ground coal 
in a ball mill for 3 hours to deposit on the coal. 
In each example, the reaction products were analyzed in the same manner as 
in Example 1, and the results are shown in Table 2. In order to maintain 
the same reaction time, the flow rate of hydrogen was changed depending on 
the reaction temperature. (In the Examples and Comparative Examples which 
follow, the same procedure as above was employed.) 
COMATIVE EXAMPLES 1 AND 2 
The procedure of Example 1 was repeated wherein the ferric chloride was not 
added, and the coal was reacted at 795.degree. C. (Comparative Example 1) 
or 740.degree. C. (Comparative Example 2). In each example, the reaction 
products were analyzed in the same manner as in Example 1, and the results 
are shown in Table 2. 
COMATIVE EXAMPLES 3 AND 4 
The procedure of Example 1 was repeated wherein the type of the metal 
compound to be added and the reaction temperature were changed as follows: 
______________________________________ 
Comparative Type of Reaction 
Example Metal Compound 
Temperature 
______________________________________ 
3 Cobalt sulfide 
730.degree. C. 
4 Molybdenum 725.degree. C. 
oxide 
______________________________________ 
In each example, the reaction products were analyzed in the same manner as 
in Example 1, and the results are shown in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Example No. Comparative Example No. 
1 2 3 4 5 1 2 3 4 
__________________________________________________________________________ 
Metal Compound 
Iron Iron 
Nickel 
Cobalt 
Palladium 
-- -- Cobalt 
Molyb- 
chloride 
sulfate 
sulfate 
phosphate 
chloride Sulfide 
denum 
oxide 
Pressure (kg/cm.sup.2) 
70 70 70 70 70 70 70 70 70 
Temperature (.degree.C.) 
730 740 745 760 775 795 740 730 725 
Conversion (%)*.sup.1 
Methane 26.7 25.1 
24.2 
24.8 29.3 25.5 
20.9 
24.1 
29.5 
Ethane 5.8 5.7 5.8 4.8 4.4 3.6 5.5 5.6 4.2 
CO + CO.sub.2 
7.3 7.0 6.9 7.1 7.9 7.8 6.1 6.7 6.2 
Gasoline Fraction 
10.3 12.8 
12.1 
10.7 9.8 6.6 5.2 7.2 6.9 
Oil*.sup.2 
14.0 12.2 
11.8 
11.4 8.1 5.0 6.3 9.2 5.2 
Char 35.9 37.2 
39.2 
41.2 40.5 51.5 
56.0 
47.2 
48.0 
__________________________________________________________________________ 
Note: 
*.sup.1 The conversion is a conversion from coal on the basis of carbon, 
expressed in percentage. 
*.sup.2 The light oil content of the oil is: from 60 to 70% by weight in 
Examples 1 to 5, and from 30 to 40% by weight in Comparative Examples 1 t 
4. 
EXAMPLES 6 AND 7 
The procedure of Example 1 was repeated wherein the type of the metal 
compound to be added and the reaction temperature were changed; i.e., 
ferric nitrate (Example 6) or nickel nitrate (Example 7) was used in place 
of ferric chloride, and in each case, the reaction was performed at the 
temperature of 650.degree. C., 700.degree. C., 750.degree. C., 800.degree. 
C., and 850.degree. C. The reaction products were analyzed in the same 
manner as in Example 1. In FIG. 1, the conversions of the coal into the 
methane and gasoline fraction, and the total conversion are plotted 
against temperature, in which the line "A" indicates the results of 
Example 6 and the line "B" indicates the results of Example 7. 
COMATIVE EXAMPLE 5 
The procedure of Examples 6 and 7 was repeated wherein the ferric nitrate 
and nickel nitrate were not added, and only the finely ground coal was 
used to effect the cracking reaction. The reaction products were analyzed 
in the same manner as in Example 1. Also in FIG. 1, the conversions of the 
coal into the methane and gasoline fraction, and the total conversion are 
plotted against temperature, and indicated by the solid line "C". 
EXAMPLE 8 
The same finely ground coal as used in Example 1 (10 g) was added to 500 ml 
of distilled water in which 0.7 g (anhydrous basis) of ferric nitrate had 
been previously dissolved, and the resulting mixture was stirred for 30 
minutes. Then, 60 ml of distilled water with 0.6 g of potassium hydroxide 
dissolved therein was added to the mixture and stirred over one day and 
night. The precipitated iron hydroxide/coal mixture was filtered off with 
suction and fully washed with water until any potassium hydroxide was 
detected in the filtrate. 
Then, the iron hydroxide/coal mixture was dried at 75.degree. C. under a 
reduced pressure of 20 mmHg to adjust its water content to 5 parts by 
weight per 100 parts by weight of the mixture. 
Using the thus-prepared iron hydroxide/coal mixture, the procedure of 
Example 1 was repeated wherein the reaction temperature was changed to 
680.degree. C. The reaction products were analyzed in the same manner as 
in Example 1. 
On basis of the analytical results, the conversion of the coal into each 
reaction product (carbon basis) was calculated, and the results are shown 
in Table 3. 
EXAMPLE 9 
The procedure of Example 8 was repeated wherein the type and amount of the 
metal compound to be used and the reaction temperature were changed; i.e., 
0.5 g (anhydrous basis) of nickel sulfate, 0.5 g of potassium hydroxide, 
and a temperature of 660.degree. C. were used in place of 0.7 g of ferric 
nitrate, 0.6 g of potassium hydroxide, and the temperature of 680.degree. 
C. The reaction products were analyzed in the same manner as in Example 1, 
and the results are shown in Table 3. 
EXAMPLES 10 TO 13 
In these examples, iron oxide, cobalt hydroxide, cobalt carbonate (basic), 
and palladium oxide, all being commercially available high purity 
reagents, were used as metal compounds. Each metal compound (0.3 g) was 
finely ground to 50 .mu.m or less, and placed in a ball mill together with 
500 ml of distilled water. In the ball mill, 10 g of the same finely 
ground coal as used in Example 8 was placed, and the resulting mixture was 
stirred for 5 hours. At the end of the time, the mixture was filtered and 
dried to produce a metal compound-added coal. This metal compound-added 
coal was dried at 75.degree. C. under a reduced pressure of 20 mmHg to 
adjust the water content to 5 parts by weight per 100 parts by weight 
thereof. The metal compound-added coal was reacted in the same manner as 
in Example 8 except that the reaction temperature was set at 700.degree. 
C., 690.degree. C., 670.degree. C., and 680.degree. C. The reaction 
products were analyzed in the same manner as in Example 1, and the results 
are shown in Table 3. 
COMATIVE EXAMPLE 6 
The procedure of Example 8 was repeated wherein the coal ground was dried 
without the addition of the metal compounds and cracked at a temperature 
of 670.degree. C. The reaction products were analyzed in the same manner 
as in Example 1, and the results are shown in Table 3. 
TABLE 3 
__________________________________________________________________________ 
Example No. Comparative 
8 9 10 11 12 13 Example 6 
__________________________________________________________________________ 
Metal Compound 
Iron Nickel 
Iron 
Cobalt 
Cobalt 
Palladium 
-- 
hydroxide 
hydroxide 
oxide 
hydroxide 
carbonate 
oxide 
Pressure (kg/cm.sup.2) 
70 70 70 70 70 70 70 
Temperature (.degree.C.) 
680 660 700 690 670 680 670 
Conversion*.sup.1 (%) 
Methane 22.1 20.9 24.9 
23.3 23.2 26.8 18.2 
Ethane 12.4 13.6 9.7 11.2 9.3 7.3 5.1 
CO + CO.sub.2 
7.0 7.2 6.9 7.3 6.8 7.5 5.8 
Gasoline Fraction 
14.8 16.4 8.7 12.9 11.8 8.6 2.9 
Oil*.sup.2 
15.0 13.9 13.2 
11.4 13.7 9.0 7.6 
Char 28.7 28.0 36.6 
33.9 35.2 40.8 60.4 
__________________________________________________________________________ 
Note: 
*.sup.1 The conversion is a conversion from coal on the basis of carbon, 
expressed in percentage. 
*.sup.2 The light oil content is: from 60 to 70% by weight in Examples 8, 
9, 11, and 12, 45% by weight in Example 10, and 33% by weight in 
Comparative Example 6. 
EXAMPLES 14 AND 15 
The procedure of Example 10 was repeated wherein the metal compouhnd to be 
added and the reaction temperature were changed; i.e., nickel oxide 
(Example 14) or cobalt hydroxide (Example 15) was used in place of iron 
oxide and in each case, the cracking reaction was performed at a 
temperature of from 600.degree. to 830.degree. C. The reaction products 
were analyzed in the same manner as in Example 1. On basis of the 
analytical results, the conversions of the coal into the ethane and 
gasoline fraction, and the total conversion was calculated, and plotted 
against temperature in FIG. 2. In FIG. 2, the line "D" indicates the 
results of Example 14, and the line "E" indicates the results of Example 
15. 
COMATIVE EXAMPLE 7 
The procedure of Examples 14 and 15 was repeated wherein the metal 
compounds were not added; i.e. the coal was cracked in the absence of the 
metal compounds. The conversions of the coal into the ethane and gasoline 
fraction, and the total conversion were plotted against temperature, as 
shown in FIG. 2 by the solid line "F". 
EXAMPLE 16 
A reactor made of nickel-chromium-iron alloy (Incoloy 800: trademark) was 
divided into two zones, a first reaction zone and a second reaction zone. 
The first reaction zone was connected to a coal-supplying unit at one end 
thereof. A coal feed was introduced into the first reaction zone, and 
thermally cracked at a high rate. The thermal cracking reaction was 
performed so that the residence time of a cracked product/hydrogen 
(introduced for the reaction) stream was less than 1 second. In the second 
reaction zone, the residence time of the cracked product/hydrogen stream 
was set at 6 seconds. The first and second reaction zones were connected 
to each other by means of a pipe of small diameter, which was designed so 
that the time taken for the cracked product/hydrogen stream to pass 
therethrough was 50 milliseconds. The first and second reaction zones were 
provided with different electric heaters for heating. 
The temperatures of the first and second reaction zones were set at 
725.degree. C. and 800.degree. C., respectively, and the pressure in the 
reactor was maintained at 70 kg/cm.sup.2. Moreover, the hydrogen gas for 
the reaction was passed through the reactor so that the above-described 
residence times were attained. 
A brown coal powder from Australia on which ferric chloride had been 
deposited in the same manner as in Example 1 was introduced into the 
reactor at a rate of 1 g per minute, and reacted. The weight ratio of the 
hydrogen (introduced for the reaction) to the coal was 1.6/1. Reaction 
products were cooled and analyzed in the same manner as in Example 1. 
On basis of the analytical results, the conversion of the coal into each 
product (carbon basis) was determined, and the results are shown in Table 
4. 
EXAMPLES 17 TO 19 
The procedure of Example 16 was repeated wherein the type of the metal 
compound and the temperature in the first reaction zone were changed as 
follows: 
______________________________________ 
Example Type of Additive 
Temperature 
______________________________________ 
17 Ferrous sulfate 
740.degree. C. 
18 Nickel sulfate 
745.degree. C. 
19 Cobalt nitrate 
755.degree. C. 
______________________________________ 
The results are shown in Table 4. 
COMATIVE EXAMPLE 8 
The procedure of Example 16 was repeated wherein the metal compound was not 
added, and the brown coal powder from Australia was reacted at the first 
reaction temperature of 740.degree. C. The results are shown in Table 4. 
TABLE 4 
______________________________________ 
Com- 
parative 
Example No. Ex- 
16 17 18 19 ample 8 
______________________________________ 
Metal Compound 
Iron Iron Nickel 
Cobalt 
-- 
chlo- sulfate sulfate 
nitrate 
ride 
Pressure (kg/cm.sup.2) 
70 70 70 70 70 
Temperature (.degree.C.) 
1st Reaction Zone 
725 740 745 755 740 
2nd Reaction Zone 
800 800 800 800 800 
Conversion*.sup.1 (%) 
Methane 32.8 31.6 30.8 29.3 24.2 
Ethane 5.0 4.9 5.2 4.0 4.7 
CO + CO.sub.2 
7.4 7.2 7.4 7.6 6.6 
Gasoline Fraction 
13.6 15.0 15.2 12.3 6.1 
Oil*.sup.2 6.7 5.9 7.4 6.9 5.4 
Char 34.5 35.4 36.7 39.9 53.0 
______________________________________ 
Note: 
*.sup.1 The conversion is a conversion from coal on the basis of carbon, 
expressed in percentage. 
*.sup.2 The light oil content is: from 60 to 70% by weight in Examples 16 
to 19, and 37% by weight in Comparative Example 8. 
EXAMPLE 20 
The same reactor as used in Example 16 was used, and the temperatures of 
the first and second reaction zones were set to 670.degree. C. and 
800.degree. C., respectively. A brown coal powder from Australia on which 
iron hydroxide had been deposited in the same manner as in Example 8 was 
introduced into the reactor at a rate of 1 gram per minute and reacted. 
The results are shown in Table 5. 
EXAMPLES 21 TO 23 
A thermal cracking reaction was performed under the same conditions as in 
Example 20 except that the temperature of the first reaction zone and the 
metal compound were changed. 
The results are shown in Table 5. 
COMATIVE EXAMPLE 9 
The procedure of Example 20 was repeated wherein the brown coal powder from 
Australia ground and dried without the addition of the metal compound was 
used, and the temperature of the first reaction zone was set at 
670.degree. C. 
TABLE 5 
__________________________________________________________________________ 
Example No. Comparative 
20 21 22 23 Example 9 
__________________________________________________________________________ 
Metal Compound 
Iron Nickel 
Cobalt 
Nickel 
-- 
hydroxide 
hydroxide 
hydroxide 
carbonate 
Pressure (kg/cm.sup.2) 
70 70 70 70 70 
Temperature (.degree.C.) 
1st Reaction Zone 
670 650 690 660 670 
2nd Reaction Zone 
800 800 800 800 800 
Conversion*.sup.1 (%) 
Methane 28.3 25.9 28.7 27.1 23.1 
Ethane 11.8 12.7 10.9 11.3 4.5 
CO + CO.sub.2 
7.3 7.4 7.6 7.4 6.3 
Gasoline Fraction 
17.1 18.8 16.9 17.3 5.8 
Oil*.sup.2 
7.0 7.6 6.3 6.9 6.1 
Char 28.5 27.6 30.6 30.0 54.2 
__________________________________________________________________________ 
Note: 
*.sup.1 The conversion is a conversion from coal on the basis of carbon, 
expressed in percentage. 
*.sup.2 The light oil content is: from 60 to 70% by weight in Examples 20 
to 23, and 38% by weight in Comparative Example 9. 
It is seen from the results shown in Table 2 and 3 and FIG. 1 and 2 that 
carbonaceous substances can be converted into gasoline fraction and light 
oils in large amounts in thermal cracking of carbonaceous substances when 
performed in the presence of the metal compounds of the present invention, 
and also seen from the results shown in Tables 4 and 5 that the gasoline 
fraction conversion is further increased by cracking thermally cracked 
carbonaceous substance at an increased temperature in the later stage of 
the thermal cracking. 
While the invention has been described in detail and with reference to 
specific embodiment thereof, it will be apparent to one skilled in the art 
that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.