To learn more, view our Privacy Policy. Log In Sign Up. Download Free PDF. Simultaneous liquefaction of a subbituminous coal and upgrading of bitumen with molten ZnCl2-based catalysts Fuel Processing Technology, Amit Chakma. Download PDF. A short summary of this paper. Simultaneous liquefaction of a subbituminous coal and upgrading of bitumen with molten ZnCl2-based catalysts.
V, Amsterdam Simultaneous liquefaction of a subbituminous coal and upgrading of bitumen with molten ZnCbased catalysts A. C h a k m a Department of Chemical and Petroleum Engineering, The University of Calgary, Calgary, Alberta, T2N 1N4 Canada Received January 28th, ; accepted in revised form October 27th, Abstract Molten halide catalysts have been found to have excellent cracking activity towards coal and bitumen-related structures as has been reported in the literature.
Upgrading experi- ments have been carried out in a batch autoclave to study the effectiveness of molten halide catalysts consisting of ZnC12 and its mixtures with MoC15, on simultaneous liquefaction of a subbituminous coal and upgrading of Athabasca bitumen.
Two methods of catalyst addi- tion to the reaction slurry were compared. Impregnation of the coal with a catalyst-saturated methanol solution was found to be more effective than direct addition of the pulverized catalyst.
The effects of different variables such as temperature, reaction time, catalyst quantity and catalyst formulations were studied. Lenz et al. In this work, we have examined coprocessing of Athabasca bitumen and a subbituminous coal using molten halide catalysts. High coal oil conversion rates and a synergistic effect on the conversion have been reported by several authors [2, 3]. The synergism is believed to be due to the solvolytic effects provided by the bitumen in which bitumen solubil- izes the coal particles and therefore makes it easier to break its physical bonds.
Bitumen may also act as a hydrogen donor solvent. The aliphatic hydrogen of the bitumen may help in the cleavage of coal structures. On its part, coal may enhance the upgrading of bitumen due to the presence of inorganics such as pyrite, which may provide beneficial catalytic effects for the upgrading of bitumen.
Extensive demetallation, deoxygenation and desulphurization of the liquid products have also been reported [4]. Fouda et al. They found that the extent of oxygen, vanadium and nickel removal increases while coke formation was found to decrease. It is believed that metals such as vanadium, are adsorbed onto the surface of the unconverted coal. Catalytic coprocessing While thermal coprocessing provides all the previously mentioned advant- ages of coprocessing, the liquid yields are rather low.
As such catalytic coprocessing is the preferred choice. The use of a catalyst may enhance coal conversion and liquid yields. Several different catalysts have been investigated for coprocessing. Mosphedis et al.
However, the quality of the products was found to depend on the type of coal and solvent bitumen, coker gas oil, heavy oil, etc. Curtis et al. Cugini et al. Molten halide catalysts have long been used in the liquefaction of coal. Zielke et al. They also carried out continuous hydroliquefaction of subbituminous coal over molten ZnCl2 and obtained octane-rich gasoline-range products [11].
The catalytic action is suggested to proceed via an ionic mechanism which cleaves bonds in polyaro- matic compounds, but is unable to open monoaromatic rings [12]. The main problem associated with ZnCbased catalysts are: i corrosion of the process- ing equipment, and ii catalyst recovery.
Nomura and coworkers [] through a series of studies have shown good conversion rates as well as high liquid yields from different coals, when combinations of several different metal chlorides were used as catalysts. Also, the amount of consumed hydrogen was lowest when this mixture was used [14]. SnCcontaining salts were shown to give higher yields of both hexane-soluble and benzene-soluble fractions, and lower yields of gases, than ZnCl2, and ZnCKC1 NaC1 salts [16].
ZnCl2 has also been found to be an excellent catalyst for converting asphal- tenes into maltenes. Chakma et al. CuC1 was not as effective, and decreased the activity of ZnCl2 when added to it. Nomura et al. Also the sulphur contents of the pentane-soluble and benzene- soluble fractions were lower when MoCcontaining catalysts were used. To achieve the above-stated objective an experimental program was initiated.
Selected properties of this bitumen are shown in Table 1. Selected p r o p e r t i e s of the coal used are shown in Table 2. Apparatus The experiments were carried out in a stainless steel, bolted closure, stirred a u t o c l a v e with an i n t e r n a l v o l u m e of ml.
Due to the high corrosive impact of m o l t e n halide c a t a l y s t s on stainless steel, c e r t a i n changes had to be made inside the autoclave. Typical temperature profile during heating, experimentation.
This separ- ated the t o l u e n e insolubles TI. Basic product workup procedure. The filter cake was crushed and rinsed with an additional ml pentane. The weight of the filter cake was the weight of the pentane-insoluble fraction PI , or asphaltenes. The pressure was then lowered to 40 mbar to evaporate the remaining toluene.
The evaporation was stopped when the weight of the remaining pentane solubles PS , also called maltenes, and the weight of the PI, or the asphaltenes, approximately equalled the weight of the original sample taken from the TS fraction.
Analyses of products The viscosity of the total toluene-soluble fraction was measured when suffi- cient volume of this fraction was recovered. It also resulted in severe corrosion of the autoclave. The second method used was impregnation of the catalyst on the coal as outlined in the sample preparation section. The maltene yield for the impregnated catalyst decreased a little, from While a significant decrease in the TI fraction was noticed, from The gas yield also increased from It is evident that the catalyst impregnated coal provided higher catalytic activity than directly added cata- lyst.
The corrosion problem was also minimal when impregnated catalyst was used. Subsequent experiments were carried out with impregnated catalysts only.
In general, as the temperature increased coking increased at the expense of maltene production. To update from the earlier versions before 4. The manual is not included in this update module. This module's size is large. To download the module requires a long time. After downloading the installation module, double-click the module on the computer that you want to install to.
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