NL7908769A - METHOD FOR CONVERTING A SOLID CARBON-CONTAINING MATERIAL INTO A FLUID. - Google Patents

Description

f 70 8827

Process for converting solid carbonaceous materials into fluid products.

The invention relates to the conversion of carbonaceous materials, in particular coal, into gaseous or liquid products. In view of the steady increase in the demand for hydrocarbon products from petroleum and natural gas and the increasing dependence on imports of petroleum and natural gas to meet this need, the demand for the development of alternative energy sources is becoming increasingly pronounced. In view of the relatively large amount of available coal, the advancement of mining technology and the progressively increasing cost of other forms of energy, more complete exploitation of coal resources has become markedly attractive.

Methods for converting coal to liquid and gaseous fuels are known. For example, e.g. through the 15 Lurgi, Koppers-Totzek, Sygas, Oo ^ Acceptor, BiGas and Synthane and other related processes different grades of solid coal converted into various gaseous products. Likewise, the PAMC0 and Synthoil processes convert solid coal into liquid products.

20 Coal is generally subdivided in hst into the qualities anthracite, semi-anthracite, bituminous and sub-bituminous coal and lignite. Most conversion processes utilize bituminous, semi-bituminous and brown coal-like non-coagulating coal types which generally form the fuel material for steam boilers and power plants. Anthracite and semi-anthracite are generally unsuitable for conversion because they have a low volatile content, are less reactive, and have relatively little stock. They are generally easily sold for domestic and commercial central heating systems. Low quality brown coal is generally not considered satisfactory for the known conversion processes because of the low calorific value, and high water and ash contents. Bituminous, sub-bituminous and non-coking coal have mostly been used for steam and electricity generation rather than conversion processes. Generally, coal conversion has only been economically possible when reserves of bituminous, sub-bituminous and non-coking coal were located at a far distance from highly industrialized or populated areas. Even though coal is a relatively abundant source of energy, in fact few coal reserves are known with which an economical conversion to a liquid product can be carried out according to the known conversion processes.

The known conversion systems are generally slow and energy intensive since the coal must be heated to between 400 and 1100 ° C and the heated solid wastes must be separated from the liquefied or gasified carbonaceous materials. In the liquefaction processes, the separation is performed by filtration and centrifugation which are relatively slow and incomplete, and limit the speed of the process. In gasification processes, the separation is carried out by scrubbers that are expensive in construction since they consume large amounts of energy in operation. In all such processes, the solid waste materials also have to be cooled, which leads to extra energy loss, while at the same time environmental disposal presents problems.

Certain impurities in the coal have been identified as undesirable pollutants that form stable oxides in the conversion processes, usually or in particular sulfur oxides, which are carried down the drain. Another such contamination is nitrogen. Some volatile metallic 7.9 O S 7 β 9 * 3 impurities may also be included in the gaseous or liquid conversion products. These include arsenic, beryllium, cadmium, lead, mercury and selenium. Consequently, the known conversion systems are also subject to environmental control as required by the government.

Until now, coal conversion processes have typically attempted to control pollutant emissions by installing an anti-pollution device in the system. However, this requires an elaborate large-sized device Ί0, greatly increasing investment costs, operating costs and energy consumption for operating the device.

The object of the invention is to considerably reduce, eliminate or avoid these disadvantages of the known carbon conversion systems. The energy requirement for the conversion, the environmental hazards and the degree of conversion control are considerably reduced. At the same time, the invention increases processing speed because problems of quenching solids, such as occur during separation of large amounts of finely divided solids from gaseous or liquid products, are avoided.

The invention further provides a purified product which is free from large amounts of impurities while also avoiding the removal of solids which gave rise to difficulties in the known systems. Sr also provides an improved quality product produced from coal deposits which have hitherto been considered not useful for conversion to fluid products.

The invention thus provides a simple method for rapidly converting carbonaceous material into a fluid product of a liquid or gaseous hydrocarbon. The process also provides a fluid hydrocarbon product of excellent purity and quality.

A amalgam of carbonaceous and non-carbonaceous 7905739 '* ** .-- 4-fine particles, "preferably ash and coal, is first dispersed in a suspension liquid, such as water, to form a thick suspension. The fine particles are preferably formed by crushing the coal from a mine in a ball mill, a mill with stirring media, etc. Optionally, the fine particles may consist of the waste from a coal washing plant or wax stones from a settling basin of a coal washing plant.

An agglomerating liquid is added to the suspension which is lyophobic to both the suspension liquid and the non-carbonaceous fines and lyophilic to the carbonaceous fines. The agglomerating liquid is preferably a hydrocarbon that can be volatilized and / or carbonized with the carbonaceous fine particles as described below, and has an initial boiling point of greater than about 65 ° C, preferably greater than 150 ° C.

The mixture is then stirred to preferentially agglomerate the carbonaceous fine particles into discrete agglomerates, the non-carbonaceous fine particles remaining substantially unagglomerated in the mixture. The agglomerated carbonaceous fine particles are then separated from the mixture. The chemical and physical properties of the discrete agglomerates are almost completely uniform and remain virtually constant for a considerable period of time. The size and packing (density) of the agglomerates are almost uniform, while the size can be controlled by the composition and percentage of the liquid and the intensity and duration of stirring. The ash content is uniform and low, generally less than 4 to 6.5 $. The moisture content of the discrete agglomerates is uniformly distributed and is usually in the range of about 7 to 20 $. Due to the agglomerating liquid, the carbon particles of the discrete agglomerates are coated, whereby the agglomerates become substantially inert to atmospheric oxidation and the chemical and physical properties of 7908769 remain there for long periods of time. 2After separation, the discrete agglomerates are heated to a temperature above 400 ° C in a controlled atmosphere to form a fluid hydrocarbon product.

The hydrocarbon product thus formed can be liquid or gaseous depending on the heating temperature and the amount as well as the chemical composition of the adjusted atmosphere. The hydrocarbon product always has special properties which are caused by the special purity and the uniform constant chemical and physical properties of the discrete agglomerates. In particular, a higher hydrocarbon product yield is obtained due to the uniform size, packing, moisture content and oxidation of the discrete agglomerates. Also, the hydrocarbon product has a significantly lower solid contamination and significantly less impurities such as sulfur, lead, beryllium, cadmium and the like caused by the separation of the non-carbonaceous materials. Moreover, it has a higher calorific value than the products of the hitherto known conversion processes because of the beneficial effect on the coal by the agglomerating hydrocarbon liquid.

Other details, objects and advantages of the invention will now be explained with reference to the following description of the preferred method.

The accompanying drawings illustrate the preferred embodiments of the invention and the preferred methods for practicing the invention wherein;

Fig. 1 is a schematic representation illustrating a method of converting coal to a gas according to the invention;

Fig. 2 is a schematic representation of another method of converting coal into a gas according to the invention; 7903739 * 9 ¥ - 6 -

Pig. 3 is a schematic representation of a method of converting coal into a liquid according to the invention; and

Pig. 4 is a schematic diagram illustrating another method of converting coal to a liquid according to the invention.

The reactions fundamental to the conversion of carbonaceous material can be described as hydrogenation or, optionally, decarbonization. Hydrogenation is herein defined as the addition of hydrogen to a hydrocarbon molecule, while decarbonization is defined as the removal of a carbon source from "a hydrocarbon molecule, usually the more complex molecules."

The conversion of coal into a fluid product basically involves converting a heavy hydrocarbon with a. carbon to hydrogen atomic ratio of about 1: 1 in methane, which has a carbon to hydrogen ratio of 1: 4. Hydrogenation generally takes place either via hydrogenolysis, whereby gaseous hydrogen is reacted with the heavy hydrocarbon according to the general reactions CA + s2 - »CE4 (1) or hydrolysis, in which steam is converted with the heavy hydrocarbon according to the general reactions reactions

CnEm + xH ^ O - ^ y CH ^ + z CO2 + wHg (2) 25 In the decarbonization processes, a carbon product such as carbon dioxide, coke or charcoal is formed which is then removed from the system. Carbon dioxide is formed by oxygenolysis whereby the hydrocarbon is heated with oxygen according to the reactions 3 ° = A ♦ ^ ° 2 -> f <* 4 + 4afc ° 2 (3)

The carbon dioxide is generally removed by washing the gas with an amine or a hot potassium carbonate solution. The charcoal is normally formed by pyrolysis or heating the hydrocarbon to cracking temperatures. Pyrolysis proceeds according to the reaction: CH - * 7 CE. + C (4) n m * 4 4 4 5 During the course of each of the basic conversions, a large number of intermediates are formed. It is believed that the chemical equilibrium that determines the product yields of the conversion method can be specifically depicted as follows: 7903769 - 8 -

TA3EL A

Balance in conversion reactions

Reaction heat of reaction volume- Svenwichts- Ho.

H (kcal / mol at constant 298 ° K (25 ° C)) ring (X) _ (AT) _ o + o -ico -94.056 1-1 (5) (22) G + CO. -> 2C0 +41,203 1 - 2 (CO) 2 (6) (co2) C + H * 0 - * H, + CO +31,356 1 - 2 (52 ^ C °) (7) • (h2o) CO + H „0 - * ïï„ + C0 „- 9,847 2 - 2 (H2 ^ C02 ^ (8) 2 2 2 (c5T (e2ö) CO + 3H? -» CH + HO -49,243 4 - 2 ^ CH4 ^ H2 ° ^ (9) (co) (h2) 3 C + 2H "- * CH -17,889 2 - 1 ^ CH4 ^ (10)

4 O

(H2) 2 CO2 + 4H2 - * CH4 + 2H20 -39,410 5 - 3 (^ -4) (^ 2 ° ^ (11) (co2) (h2) 4 C + 2H20 -'t 2H2 + C02 +21, 510 2 - 3 (-2 ^ ^ C02 ^ (12) (h2o) 2 CH4 + C02 —2C0 + 2H2 +59,093 2 - 4 (C0) 2 (H2) 2 (13) (ch4) (co2) 2C + Hn - * CnH „+54,163 1 - 1 ^ ° 2Ξ2 ^ (U) 2 2 2 n ^ r 2CH4 -> C2H2 + 3H2 .... +39,918 2 - 4 ^ C2E2 ^ H2 ^ (15) jf4) 2 2 2CH4 - * C2H4 + 2H2 +43,246 2 - 3 (C2Hi ^ H2 ^ ~ (16) (οξ4) 2 C „H, + —4 CnH, + +32,710 1-2 (C2Ha) (E2 ^ (17) 24 T ^ l 7908769 Λ - 9 - TABLE vervolg (continued) (co) (H Ϋ 'GH. + 3.0 - * GO + 3H. +49,242 2 - 4 - (18) * 2 2 (oh4) (h2o) 3rd development of coal conversion processes are complicated by the fact that not only do most of the reactions of Table A indeed take place at a certain point in the conversion of the coal into a fluid product, but it is also believed that at some stage of the conversion most of the the aforementioned equilibria co-exist The main consideration in designing a conversion process 10 in view of the previous equation i s the enthalpy change (4H) of the different reactions. The enthalpy or reaction heat is a measure of the endothermicity (+ ΔΗ) or exothermicity (-43) of the reaction and therefore gives an indication as to whether reactions 5-13 are shifted to the right or left by the addition or removal of heat. . In order to produce a low molecular weight fluid product from the higher molecular materials in coal in the most efficient and economical manner, it is important to balance the enthalpy change of the different stages, thereby reducing the net thermal energy transfer to and from the working method is minimized.

According to Table A, the volume change (Δ7) indicates whether the effect of a pressure increase causes the equilibrium to be shifted to the right or left depending on the 25 volume load.

The equilibrium constant (K ^) gives an indication of the composition of the final gas mixture at a given temperature after the chemical equilibrium has been established. Table B is a list of values of respective balance stants 30 of each reaction in Table A for three different temperatures.

790S769 4 »- 10 -

TABLE · B

Value equilibrium constant in conversion reactions

Balance,

value of K.

constant ^

(Κυ) at 527 ° C 727 ° C 927 ° C

^ C02 ^ 6.709 x 1025 4.751 x 1020 1.758 x ΙΟ17 (5) 'Töp "(co) 2 1.098 x 102 1.900 57.09 (6)" (cop · - (g2 ^ co ^ 4.599 X 102 2.609 59.77 ( 7) f. TÊpr "^ 52 ^ CQ2 ^ 4,053 1,374 0.6966 (8) '(co) (h2o) (CHd) (H2o) 8.3 21 X 102 4.585 59.585 (9)' (co) (h2) 3 ^ CH4 ^ 1,411 9,829 x 102 1,608 x 102 (10) * (h2) 2 '2 (C54) (H20) 2,185 χ 102 3i190 85,557 (11)' (co2) (h2) 4 ^ ^ C ° 2 ^ 0 , 1777 5.608 28.01. (12) »(h2o) 2 (C °) (3g) 7.722 χ 10“ 5 19.52 3.548 χ 103 (13) '(ch4) (co2)' G2H2 ^ 1.602 x 10 ' 12 1,337 χ 10'9 1,156 x 10'7 (14) 'ΤςΓ (C2H2) (H2) xa> 017 x 10-13 1j5g4 χ 10 “7 4> 474 x 10-4 (15) r (ch4) 2 ( C2Hd) (H2) 1> 021 x 10-7 êf939 x 10-5 5f54Q χ t0-5 (-16) 1 (ch4) 2 7900769 - 11 - TABLE 3 (continued) (C2Hd) (S2) 4j5j7 χ 10 -5 o, 3443 6,224 (17) '

^ C2V

(co) (h2) 3 5} 120 x 10-2 35.56 2.473 x 103 (-ia) * (CH4) (H20)

Where S tends to increase cLe at elevated temperature, an increase in process temperature will shift the reaction equilibrium of the respective reaction equation in Table A to the right. Where K with increasing temperature

P

As the temperature decreases, a decrease in the process temperature will shift the reaction equilibrium to the right.

"O The time for setting the equilibrium conditions in reactions (5) - (18) is determined by the rate constants of both the right and left reactions. The rate constants are a function of the reactivity of the different types of reactions and for many conversion reactions 15. the presence of a catalyst, either homogeneous or hot, is required to achieve equilibrium conditions within an acceptable period of time.

Heterogeneous catalysts are materials that provide a surface on which reactions between gas molecules take place due to the surface forces exerted by certain active materials or centers. However, these catalysts also appear to attract molecules other than those with which they must react. In particular, polar contaminants of the coal, such as sulfur, nitrogen, oxygen and metal compounds, deposit on the catalyst, block the active centers and eventually poison the catalyst. Accordingly, for processes based on the catalytic conversion of coal, it is essential that the reacting gases prepared from the coal be purified before contacting the catalyst.

The method currently described has been developed in such a way that J § 0 0 7? 9 * * - 12 - Please note that the above considerations have been carefully considered. In the conversion steps, the enthalpy conditions of the various reactions that take place are carefully analyzed, after which conversion is effected via an advantageous combination of steps. In the various stages, the pressure, temperature, volume, process speed and other variables are adjusted to achieve desired product ratios.

The known conversion processes started from a carbonaceous feed material, in particular coal, with known constant physical and chemical properties. However, the physical and chemical properties of coal vary considerably from deposit to deposit and further within the same deposit.

The carbonaceous molecules that are hydrogenated or carbonized cover a wide range of molecular weights and complex structures. Moreover, the carbonaceous feed is non-uniformly contaminated with non-carbonaceous material. Thus, the known carbon conversion methods had to be adapted individually to the widely varying qualities and types of coal.

Furthermore, surface effects, such as oxidation and moisture, cause variations in the properties of a single chunk or a single particle of coal. The deviation in physical and chemical properties of the various grades of coal and the non-uniformity of these properties within a single coal deposit have so far meant that sometimes a method designed for the conversion of a given grade of coal has to be greatly modified or was even unsuitable for conversion of other grades of coal.

According to the invention, carbonaceous materials of different grades and purities are converted into carbonaceous agglomerates with known properties that are substantially constant regardless of variation in the properties of the 76G0769 f-13 carbonaceous feedstock.

In. Figure 1 converts the carbonaceous material into the fluid hydrocarbon product by first dispersing carbonaceous and non-carbonaceous fine particles of the carbonaceous material in a slurry liquid to form a thick slurry 10. The term "fine particles" as used herein means especially small particles, preferably having a diameter less than 0.590 mm (28 mesh Tyler) and typically less than 0.210 mm (65 mesh Tyler). The term "carbonaceous material" means any carbonaceous starting material which, when divided into fine particles, contains fine particles of both non-carbonaceous and carbonaceous materials. It is highly desirable that the carbonaceous material be a lower quality anthracite or coal 15 such that the carbonaceous fine particles are coal and the non-carbonaceous fine particles are ash. The term "ash" fine particles includes small particles of material such as clay and granite which are generally present as ash rather than as volatiles upon complete combustion of coal.

The thick suspension 10 can be formed from such a coal by various methods. The finely divided carbon 11 can e.g. conveyed directly from a mine to a mowing mill 12. This mill can be any suitable commercially available mowing mill such as a ball mill. Grinding the carbon to small particles effectively releases sulfur compounds and other non-carbonaceous particles. A high sulfur content such as e.g. in pyrites it is particularly undesirable, because this sulfur can inter alia interfere with the subsequent reactions in the conversion method. This is particularly effective when catalytic reactions are included in the process. Other impurities released during the crushing of the coal include oxygen and nitrogen containing compounds.

Oxygen is undesirable in the conversion method, in particular, in the hydrogenation because it increases hydrogen consumption. The presence of nitrogen in the coal results in the presence of ammonia or nitrogen oxides in the fluid product, thereby reducing its calorific value.

Optionally, the thick slurry 10 may be the underflow 14 from a conventional carbon scrubber, which typically has a relatively low solids content of about 5-15 weight percent solids in water. The underflow 14 can be mixed with a wax slurry suspension 15 of relatively high solids carbon and asfine particles, ie at least about 50 solids, formed by an aqueous dispersion of the sediment from an existing settling basin in a coal wash. installation. Mixing the underflow 14 and slurry 15 produces a thick slurry 10 with about 5 - 40, especially 20 - 25, solid coal and asfine particles. In this case, the carbonaceous and non-carbonaceous particles are already sufficiently small that sulfur compounds and other non-carbonaceous particles are free in the suspension.

Suspension 10 is processed in agitator 16 to preferentially agglomerate the carbonaceous (e.g., carbon) fine particles, while the non-carbonaceous (e.g., ash) fine particles remain substantially non-agglomerated and dispersed in the suspension. Agglomerating liquid 17 which is lyophobic for both the suspension liquid (eg water) and for the non-carbonaceous fines and lyophilic to the carbonaceous fines to form the suspension is added to the suspension 10 at the inlet of the agitator 16. a mixture. Lyophil in this respect means that in a dispersion system there is a significant affinity (wettability) between a. disperse component and the dispersion medium and / or another disperse component. Some examples are glue and water or rubber and benzene. Lyophobic in this respect means that in a dispers system there is virtually no affinity (wettability) between the disperse component and 7908769-15 - the dispersion medium and / or another disperse component. Examples are oil and water or olloidal "solutions" of metals.

The agglomerating liquid 17 is preferably a hydrocarbon liquid that can be reacted together with the carbonaceous small particles, as described below. Materials particularly useful for agglomerating liquid 17 are hydrocarbons with an initial boiling point greater than about 65 ° C and preferably higher than 150 ° C. Particularly suitable are light oil, light fuel oil, heavy fuel oil and kerosene. Also useful are creosote, filtered anthracene oil, hydrogenated filtered anthracene oil, lubricating oil such as SAS 20 and chlorinated biphenyls. Heavy hydrocarbon materials such as heavy crude petroleum, slate crude oil or coal tar are not preferred. Heavy hydrocarbon liquids typically contain molecular groups that are lyophilic to both non-carbonaceous fine particles and carbonaceous fine particles, and therefore do not provide the degree of separation of carbonaceous fine particles from non-carbonaceous fine particles used in the present method is preferred. Also, such heavy hydrocarbon liquids often need to be heated to provide sufficient fluidity for the practice of the invention.

The agglomerating liquid 17 is selected and added in measured amounts to control the agglomeration of the carbonaceous fines as described below. Liquid 17 is preferably added in amounts of about 2-10 wt.%, Most preferably between 3 and 7 wt.% Of the total solids content in slurry 13 for high recovery (eg, 88 - 89 wt.%). Larger amounts of liquid 17 to and above 30 wt.% Can be utilized in some cases. However, such smaller and larger quantities are not preferred because, on the one hand, sufficient agglomeration and bonding of the fine carbon particles is not obtained. On the other hand, a waste of highly refined petroleum or coal tar derivatives is generated.

The mixture of suspension 10 and agglomerating liquid 17 is mixed and stirred in the stirrer 16. The stirrer 16 may be any suitable stirrer such as a modified turbine, a disc or cone blade mixer or a recirculating tank. Preferably, however, the agitator 16 is a tank equipped with a high shear motor driven blade or agitator blade 18 which extends to the bottom portion of the tank.

When stirring in device 16, the carbonaceous fine particles are preferentially wetted by the agglomerating liquid 17, which is preferably immiscible in water, and the carbonaceous fine particles are agglomerated to coarser fine particles. The size of the agglomerates is mainly determined by the composition and the percentage of liquid 17 added to suspension 10, and is adjusted to provide the desired size and density for effective conversion to the gaseous and liquid product. For the preferred percentage of 2-10 wt% of liquid 17, the agglomerates typically have dimensions of about 1 to 2 mm. The time taken to complete the agglomeration generally depends on the degree of turbulence or agitation, with a shorter agglomeration time associated with a higher agitation speed. The degree and duration of the agitation in the device 16 are also adjusted or controlled to provide the desired size and packing (density) of the agglomerates.

The carbonaceous agglomerates impregnated JO with or on the surface of which liquid 17 is absorbed, which liquid is generally less dense than the suspension liquid, tends to float on top of the mixture. The highly agglomerated first mixture 19 is thus removed from the top of the stirrer 16 and brought to a separator 20 where the carbonaceous agglomerates 22 are separated from the suspension liquid and non-agglomerating non-carbonaceous fine particles according to size and / or density Preferably, the separator 20 is a screen sieve with an appropriate screen size, HV 100 or 200 mesh Tyler (0.150 - 0.075 nua) such as that from DSM Optionally, other types of scrapers such as slurry, cyclone or spiral separators, which are commercially available, may be used Optionally, the carbonaceous agglomerates 22 may also be separated in a floating settling tank in which the carbonaceous agglomerates 22, which tend to float, are skimmed by a rotating blade above an overflow, while the water and the non-agglomerating nist-carbonaceous fines that tend to sink from the bottom 15 of the tank al3 thick suspension 21, which contains the non-carbonaceous fine particles and is substantially free of carbonaceous fine particles and agglomerating liquid, is removed. Carbonaceous agglomerates 22 have a low content of ash and impurities, a uniform size and packing 20 (density) and an even distribution of moisture in the agglomerates. Typically, the moisture content of the discrete agglomerates falls in the range of about 7-10 ^. The low amount of non-carbonaceous materials, typically less than about L - 6.5λ >> the uniform size and packing as well as the uniform distribution of moisture by the discrete agglomerates allows the subsequent steps of the conversion method to be predictable proceed in a manner and efficient manner in accordance with the design of the various stages of the process.

The calorific values of the fluid product generally depend on the caloric value of the carbonaceous agglomerates 22. The incorporation of agglomerating liquid 1, which is a hydrocarbon, into agglomerates 22 has a favorable influence on the calorific value. of the agglomerates and thereby improves the quality of the fluid product for the 79.0 07 ”? - 18 - r calorific value,

The quality of the fluid produced according to the method of the invention is further improved in that the agglomerates 22 are protected from partial oxidation of the carbon particles upon contact with air. The agglomerating liquid 17 coats the individual carbon particles and thereby protects them from oxidation prior to the conversion process. Partial oxidation of agglomerates 22 is undesirable because it disturbs the uniformity of the chemical and physical properties and adversely affects the conversion process efficiency and the quality of the fluid product by altering the conversion processes according to reaction equations 5-19 · Consequently, the agglomerates 22 are resistant to changes in their.

Chemical and physical composition caused by oxidation and can be stored for considerably long periods, e.g., 4-6 months, without oxidation occurring. In addition, the agglomerates 22 do not require special storage facilities and can be stored in open storage rooms if desired.

At this stage, the separated carbonaceous agglomerates 22 can be processed (not shown) by pelletizing them into larger particles. The agglomerates can be pelletized to generally uniform particle sizes of 0.25-2.5 cm in diameter by feeding the agglomerates to a grain-forming disc or tumbler along with a binder liquid to form the second mixture and then this stir the mixture. Optionally, the agglomerates can be stirred, extruded or otherwise pressed into pellets after addition of a binder liquid to form the second mixture. Binder liquids particularly suitable for this purpose are heavy hydrocarbons, such as coke oven coal tar, crude slate oil, crude petroleum oil or heavy fuel oil, such as Bunker C oil, which are preferably heated to e.g. 100 ° C, to bind the binder to and within the 73Ö07 S? 19 - 19 - agglomerates. Such heating also favors uniform dewatering of the agglomerates, suitably to about 5-12 µm moisture content. Preferably, an accelerator is also included in the binder liquid to allow the binding of the binder to take place in shorter times and / or at temperatures. The heavy hydrocarbon binder liquid serves to further improve the discrete agglomerates without disturbing the uniform chemical and physical properties of the discrete agglomerates 22. As a result, the quality of a fluid conversion product of the pellets is further improved by increasing the caloric value of the fluid product. Also, the addition of the heavy hydrocarbon binder liquid improves the resistance of the carbonaceous material to atmospheric oxidation, so that the chemical and physical properties of the pellets remain constant even over longer periods than those of the discrete agglomerates 22.

According to the process of the invention, a large number of stages can be used for the final conversion of carbonaceous agglomerates 22 into a fluid product of choice. These different end conversion stages consist of different process stages designed for selected ash and moisture contents for the optimum conversion of the carbonaceous agglomerates 22 into a fluid product based on the physical 25. chemical properties of the carbonaceous feedstock. The above-described steps to remove the non-carbonaceous or asfine particles from the carbonaceous particles advantageously leads to carbonaceous agglomerates 22 having a low, uniform and generally constant ash and moisture content regardless of the source or quality of the carbonaceous material being the suspension 10 is added. The agglomerates 22 in particular have an ash content which is generally less than 6.5% for most types of coal and generally less than 4%. for the higher quality cabbages, and .. a a j / ö 9 - 20 - they generally have a moisture content of about 5-12 $. Thus, regardless of which particular conversion step is used and regardless of the preferred ash and moisture content to achieve optimal conversion of the carbonaceous material into a fluid product in accordance with the design of the particular conversion step used, it is always possible for each selected process, optimum conversion can be achieved by introducing an appropriate amount of ash and / or water into the carbonaceous agglomerates 22 where necessary. Since the ash or moisture content of the carbonaceous agglomerates 22 is known, the amount of ash and / or moisture to be introduced to achieve the optimum conversion for a given method is also known. Moreover, since the ash and moisture content of the carbonaceous agglomerates 22 is substantially uniform, the additional ash and / or moisture can be introduced at a constant rate. Consequently, the existing conversion processes can be modified and new processes can be designed without having to take into account the particular physical and chemical properties of a particular source of carbonaceous feed material such as a certain deposit of coal,

According to the conversion method illustrated in Figure 1, in the final conversion stage, the agglomerates 22 are converted to synthesis gas, a mixture of carbon monoxide and hydrogen, which can be converted to methane or heavier hydrocarbons in the presence of a catalyst. The final conversion stage is based on the partial oxidation of agglomerates 22 in the presence of oxygen and steam. If necessary, the carbonaceous agglomerates 22 are given a moisture content of 2-3 $ by addition of water 24, while they are further comminuted in a mill 26 passing through about 0.075 mm mesh sieve. Nitrogen 28 or other non-oxidizing gas is added to plant 26 with the smaller sized agglomerates being entrained in a nitrogen stream to a business bunker. The pulverized carbon agglomerates are then vented into a stream of oxygen 31 and steam 32 to a gasifier 3d in which they are partially oxidized. Gasifier 34 is a horizontal cylindrical vessel with conical ends fitted with a refractory liner 5 *

Gasifier 34 is provided with a steam jacket 36 through which the refractory liner and burners of gasifier 34 are cooled and steam 32 is generated used for the partial oxidation of the pulverized agglomerates in gasifier 34 - 10 atmospheric or low positive pressure and flame temperatures of about 1815 - 1925 ° C, the agglomerated dust, oxygen and steam will react with each other at the burner heads of gasifier 34 to form a crude synthesis gas 38 containing carbon monoxide and hydrogen.

Approximately half of the ash content remaining in the pulverized agglomerates precipitates in gasifier 34 as molten slag which is cooled in a slag quench tank 40. The non-precipitated ash is entrained with the synthesis gas 38 which exits from the gasifier with water is • 20 quenched in a first scrubber 4 ”! to wash out the entrained ash. The gas stream is then passed through a second scrubber 42 to further reduce the amount of entrained solid and through a gas cooler 44 to lower the gas temperature to about 35 ° C. Set of cooled gas is then purified from residual entrained particles in a disintegrator 55 »

Drill a waste heat boiler ά6, heat is recovered from the slag quench tank 40 and high pressure steam 48 is generated which is supplied to the turbine drives of compressors or pumps. Eater from the first scrubber 41, the second scrubber 42 and the gas cooler 44 is pumped to a clarifier 50 which removes fine slag particles such as sludge 5 '. The clarified vats are pumped from the clarifier 50 to a cooling tower 52 and then recycled through the scrubber. A water stream 54 is added to compensate for evaporation and other losses at the cooling tower 52 as well as the moisture losses in the clarifier sludge 51 ·.

Synthesis gas 38 is mainly composed of carbon monoxide, carbon dioxide and hydrogen. The main impurities are nitrogen and hydrogen sulfide which are generally removed either by a chemical reaction or by a physical absorption (not shown). Synthesis gas 58 can be processed into various chemicals, such as hydrocarbons, ammonia or methanol. Of its choice, the synthesis gas 38 can also be converted into pipeline quality gas by further purifying the gas in precipitators followed by desulfurization, water gas shift conversion, removal of excess carbon dioxide ..... and methanation (see equation 9) · 15 In Figures 2 , 3 and 4, alternative embodiments of the invention are illustrated, wherein carbonaceous agglomerates 22 are produced in the same manner as described with respect to Figure 1. Accordingly, the same reference numerals refer to the same parts of Figures 2, 3, and 4, while the method is described in the same manner as for Figure 1. However, in Figures 2, 3, and 4, the carbonaceous agglomerates 22 are described by alternative final conversion stages converted into different products.

In Fig. 2, carbonaceous agglomerates 22 are comminuted into carbonaceous particles of less than 0.85 mm in size in a pulverizer 58 and placed in a fluidized bed pretreater 60 together with steam and oxygen. The mixture of carbonaceous particles, steam and oxygen is maintained at about 70 bar gauge pressure and a temperature of about 425 ° C to conduct surface oxidation of the carbonaceous particles and delay their agglomeration properties. The partially oxidized carbonaceous particles are then supplied to the top of a gasifier 66 while additional steam and oxygen are supplied to the bottom of the gasifier 66 such that a fluidized bed of carbonaceous particles is maintained in the gasifier. Gasifier 66 is operated at a typical pressure of about 70 bar and a temperature of about 980 ° C to form a product gas 67 and charcoal 68 from the carbonaceous particles.

Product gas 67 is vented from the top of gasifier 66 while charcoal 68 is removed from the bottom. The charcoal is preferably used for firing a boiler 10 (not shown) which produces the steam required for the process. Product gas 67 contains tar, fines, sulfur compounds and light oil. The tar and fines are removed from the product gas 67 by a spray tower 68. The purified gas is passed through a displacement converter 70 to produce carbon monoxide and hydrogen with the desired ratio of hydrogen to carbon monoxide. The carbon monoxide and hydrogen from the shift converter 70 are purified in a hot carbonate scrubber 72 and a sulfur purifier 74. The purified gas of the correct hydrogen to carbon monoxide ratio is converted into a catalytic methanator 76 to produce pipeline gas. Preferably, the methanator f6 is of the type using nickel catalysts.

In the process of Figure 3, the carbonaceous agglomerates 22 are mainly converted into liquid products. The carbonaceous agglomerates are comminuted into carbonaceous particles 31 in a pulverizer 30 to about JOfi less than 0.075 am. Carbonaceous particles 81 are fed to a feed tank 82 in which they are mixed with a portion of the product oil 34 to form a thick slurry 86. Hydrogen-rich gas is added to slurry 86 and this mixture is fed into a fixed bed reactor under turbulent conditions 38 containing an immobilized Co-Mo / SiOg-Al Q catalyst. The temperature inside the reactor is 2 3

70, n 7 λ Q

* 1 '- 24 - typically about 450 ° C and the pressure is in the range of about 140 to 280 bar. The effluent from reactor 88 is fed to a vapor / liquid separator 90 in which the gases are separated from the liquids and unreacted solids. The solids solid mixture is passed to a centrifuge 92 to remove the unreacted solids. The liquid from centrifuge 92 is the product oil 84, a portion of which is recycled to the feed tank 82 to form slurry 86. The solid from centrifuge 92 is fed to a pyrolizer 93 in which an additional amount of product oil is supplied along with gases and a carbonaceous residue generally consisting of a mineral material.

Gases from the vapor / liquid separator 90 are supplied to a gas separator 94 which removes HgS and gaseous hydrocarbons from the hydrogen in the gas. NE2 and H2S are useful by-products. Hydrogen is recycled to reactor 88. The residue and gases from the pyrolysis vessel 93 and the gaseous hydrocarbons from the gas separator 94 are fed together with water and oxygen to a gasifier 96 and a shift converter 93 to provide additional hydrogen. The additional hydrogen along with the hydrogen supplied by gas separator 94 is supplied to the slurry 86 which is fed into the reactor 88. If necessary, a portion of the milled carbonaceous particles 81 may be added to gasifier 96 and shift converter 98 'to prepare an amount of hydrogen sufficient for the process need.

According to Figure 4, the carbonaceous agglomerates 22 are converted into a synthetic crude oil, as well as into gas and a flammable charcoal by yet another conversion method. Carbonaceous agglomerates 22 are comminuted to granules with a diameter of less than 0.3 cm in a comminution device 100 and rolled at successively higher temperatures in a series of four fluidized bed reactors 102-105 in this example. A fraction of the volatiles from the carbonaceous granules is released in each fluidized bed. The temperature of each bed is chosen slightly lower than the temperature at which the granules will agglomerate and the reactor bed will no longer be fluidized. The characteristic temperature of each reactor 102-105 is about 515 ° 0, 455 ° C, 540 ° C and 815 ° C, respectively.

In reactor 105, a mixture of oxygen and steam is introduced at the bottom to supply the process heat and the hot crude synthesis gas, which flows against the movement of the carbonaceous granules such that the mixture passes upwards through reactors 103 - 105 for fluidizing the beds. The volatile material removed from reactors 103-105 is fed to a scrubber 105 in which an oil-water mixture is condensed obtained from the carbon vapors of the volatile material by contacting the product gas stream with water. The condensed oil-water mixture is then passed to a separator 106 which separates the gases 108 from the condensed oil-water mixture and removes the water from the mixture by phase separation and dehydration to yield a condensed oil 110. The gas 108 from separator 106, along with gas 112 from reactor 102, is delivered to a scrubber 114 such that synthesis gas 116 is supplied to the output of scrubber 114.

Synthesis gas 116 is fed to the bottom of reactor 102 and flows against the movement of the carbonaceous particles such that gas 116 passes up through reactor 102 thereby fluidizing the bed. Condensed oil 110 is supplied to a filter 117 that removes the solid entrained from reactors 102-105. Oil from filter 117 is supplied to a fixed bed hydrotreater 11? wherein it is treated with hydrogen separated from the synthesis gas of the scrubber 114 by a separator 115 * 3 by the treatment of the oil with hydrogen in the fixed bed hydrobes-70 π p 7 5> -26-3-handling device 117 ', nitrogen and oxygen are removed from the filtered oil and a good quality synthetic crude oil 118 is obtained. It is preferred that the hydrotreating is carried out at a temperature in the range of 570 - 450 ° C in the presence of a nickel-molybdenum catalyst. Hest charcoal is removed from reactor 105. This can be gasified to produce fuel gas, burned as a boiler fuel to promote the heating of reactors 102-104, or used to produce hydrogen to treat the oil in the fixed bed hydrotreater 117. Other methods are adaptable for a constant composition carbon feed.

It is advantageous that the method of the invention is totally compatible with an efficient transport of the purified carbonaceous material. Thus, when the final conversion of the carbonaceous material is performed at a location away from the source of the carbonaceous material, the carbonaceous agglomerates 22 are easily transportable to the conversion site. Preferably, the carbonaceous agglomerates 22 are transported in a liquid thick suspension. Its choice may be to send the carbonaceous agglomerates • 22 with a conventional means of transport, such as closed freight wagons, or to form briquettes from the agglomerates 22, which are reduced to the correct size distribution before conversion.

In the aforementioned description, a method for converting a carbonaceous material into a fluid product is described in which non-carbonaceous particles are removed from the carbonaceous material before the gasification or liquefaction step. The efficiency and economy of the final conversion stage are thereby improved as significantly less non-carbonaceous material remains from the fluid product through relatively difficult <5 λ Λ Q 1.5, ü - 27 - Ί * and expensive purification and clarification procedures morden removed. The present method of converting carbonaceous material further improves the degree of conversion of the carbonaceous material into the fluid product because the carbonaceous agglomerates developed in the method have a higher carbon content, they are remarkably uniform and have constant physical and chemical properties, and because less non-carbonaceous material is processed through the end conversion stage where the removal of non-carbonaceous material is relatively slow, difficult and expensive. Also, the disclosed method is fully compatible with situations where the conversion step is carried out in a place far from the source of the carbonaceous materials since the carbonaceous agglomerates are easily transportable, preferably as a liquid thick suspension piped is being pumped.

79 0 375.9>

Claims (10)

C. the mixture is stirred to preferentially agglomerate the carbonaceous fine particles into discrete agglomerates with physical and chemical properties that are substantially uniform and substantially constant for a considerable period of time, while the non-carbonaceous fine particles are substantially not agglomerated in the mixture stay behind; D. the discrete agglomerates are separated from the mixture; Ξ. the separated discrete agglomerates are heated to at least 400 ° C to convert the agglomerates into a fluid product. 2. Process according to claim 1, characterized in that in step C the mixture is stirred to preferentially agglomerate the carbonaceous fine particles to discrete agglomerates which are substantially inert with respect to the atmospheric oxidation and in step E the separated discrete agglomerates to form a liquid product are heated. 3. Process according to claim 1, characterized in that in step C the mixture is stirred to preferentially agglomerate carbonaceous fine particles into discrete agglomerates which are substantially inert to atmospheric oxidation and in step E the discrete agglomerates separated are heated to form a gaseous product. 7903769 '_ · · * Ν - 29 - 4. A process for converting coal into a fluid product, characterized in that: A. an amalgam of fine carbon particles is dispersed in a suspension liquid to form a thick suspension; B. a liquid is added to the suspension which is lyophobic with respect to the suspension liquid and non-carbonaceous fine particles in the carbon and lyophilic with respect to the carbonaceous fine particles in the coal to form a mixture} C. the mixture is stirred to preferentially agglomerate the carbonaceous fines to discrete agglomerates having chemical and physical properties that are substantially uniform and substantially constant for a considerable period of time while the non-carbonaceous fines remain substantially unagglomerated in the mixture; D. The discrete agglomerates from the mixture are separated. 2. The separated discrete agglomerates are heated to at least 400 ° C to convert the agglomerates into the fluid product. 5. Process according to claim 4, characterized in that in step 0 the mixture is stirred to preferentially agglomerate the carbonaceous fine particles to discrete agglomerates which are substantially inert to atmospheric oxidation and in step 3 the discrete separated agglomerates are heated to form a liquid product. o. process according to claim 4, characterized in that in step G the mixture is stirred to preferentially agglomerate the carbonaceous fine particles into discrete agglomerates which are substantially inert to atmospheric oxidation and in step 2 the separated discrete agglomerates are heated to form the gaseous product, 7. Fluid product obtained from a solid carbonaceous material 7908720> f '- 30 material "prepared by: A. dispersing an amalgam of carbonaceous and non-carbonaceous fine particles in a suspension liquid to form a suspension; B. adding to the slurry a liquid that is lyophobic to the slurry liquid and the non-carbonaceous fine particles and lyophilic to the carbonaceous fine particles to form a mixture; C. Stirring the mixture to preferentially agglomerate carbonaceous fine particles into discrete agglomerates having chemical and physical properties that are substantially uniform and substantially constant for a considerable period of time while the non-carbonaceous fine particles in the mixture are substantially non-agglomerated stay; D. separating the discrete agglomerates from the mixture; Ξ. heating the separated discrete agglomerates to at least 400 ° C to convert the agglomerates into a fluid product. 8. Fluid product obtained from a solid carbonaceous material prepared according to claim 7, characterized in that in step C the mixture is stirred to preferentially agglomerate the carbonaceous fine particles to discrete agglomerates which are substantially inert with respect to atmospheric oxidation and in step 3 the separated discrete agglomerates are heated to form a liquid product. 9. Fluid product obtained from a solid carbonaceous material prepared according to claim 7, characterized in that in step C the mixture is stirred to preferentially agglomerate carbonaceous fine particles to discrete agglomerates which are substantially inert to atmospheric oxidation. and in step 3 the separated discrete agglomerates are heated to form a gaseous product. 7908769