Catalyst carbonisation

Sulphuric add, diammonium phosphate, zinc chloride and EORA tar from the Inchukalns deposit site were tested as carbonisation catalysts. The highly harmful waste acid tar is characterised by a good solubility in water therefore, in an open air depository pond, it is found as a 50 % solution in water, containing 4.3 % sul]dmric acid and 70 % sulphonic acids (R-SOjH) both on the dry matter basis with an average sulphonic add molecular mass of 610 (3,6). 

Under the effect of carbonisation catalysts, the thermal decomposition of wood components sets in at a temperature approximately by 100°C lower than in the case of non-catalysed carbonisation of wood. Table 1 lists the yield of the wood carbonisation solid residue recalculated on fixed carbon to exclude the effect of the fluctuations of volatiles and the ash content upon the charcoal yield. The fixed carbon content of charcoal in the experiments represented in Table 1 was 78% to 81%. The increased ash content of charcod was caused by the catalysts, (NH4)2HP04 and ZnCb. The yield and overall heating value of the volatile (xoducts are given in Table 1. 

Zandersons J., Zhurinsh A, Spince B. Tardenaka A (1996) Method for producing charcoal using a carbonisation catalyst. Latvian pat. No. 11995. 

All the yields given refer to one circulation of the acid (or acids) over the catalyst, but can be improved by recirculating the product, from which the water layer has bmn removed, over the catalyst. With the higher ketones, the second circulation may result in carbonisation of the catalyst, thus rendering it inefficient. 

The high purity carbon nanotubes (CNTs) used in this study were obtained by decomposition of acetylene over a powdered CoxMgi xO solid solution catalyst [19]. Different proportions of CNTs from 15 to 70% and polyacrylonitrile (PAN, Aldrich) have been mixed in an excess of acetone to obtain a slurry. After evaporation of acetone, precursor electrodes were formed by pressing the CNTs/PAN mixture at 1-2 tons/cm2. The C/C composites were formed by carbonisation of the pellets at 700-900°C for 30-420 min under nitrogen flow [20], The optimal capacitance properties of the composite were obtained for a mixture CNTs/PAN (30/70 wt%) treated at 700°C. Such C/C composite remains still quite rich in nitrogen (9 at% of N) demonstrating that PAN is an efficient nitrogen carrier. On the other hand,... 

Fluidised catalysts are also used in the synthesis of high-grade fuels from mixtures of carbon monoxide and hydrogen, obtained either by coal carbonisation or by partial oxidation of methane. An important application in the chemical industry is the oxidation of naphthalene to phthalic anhydride, as discussed by Riley(131). The kinetics of this reaction are much slower than those of catalytic cracking, and considerable difficulties have been experienced in correctly designing the system. 

Keywords carbon fibers, carbonisation, metallic catalysts, ordered carbon, x-ray diffraction. 

The catalytic influence of metals of the ferrous subgroup on the process of carbon structuring in carbonised HC is established. The influence of anionic structure of introduced salts on the process of the HC thermal decomposition and following transformations in the system metal - carbonic rest are shown. The obtained results present both scientific and practical concern at creation of catalysts for obtaining of nanostructured carbon. 

Figure 3. XRD spectrum of the catalyst, obtained from copolymer carbonisate and ammonium perhenate.

The activity of granulated rhenium catalyst, obtained from copolymer carbonisate, has been investigated in reactions of cyclohexane or ethylbenzene dehydrogenation in bed -packed quartz tube reactor at the plug flow conditions at temperatures from 650 to 900 K, the reagents feed of 30 - 100 ml/min and initial hydrocarbons partial pressure of 0.5 kPa. 

Figure 5. The temperature dependences of benzene (curve 1) and styrene (curve 2) yields at cyclohexane and ethylbenzene dehydrogenation, respectively, on the catalyst, obtained from copolymer carbonisate, containing 7 mass per cent of Re.

ABSTRACT Sawdust, shavings, veneer shorn and other fine residues of the woodworking industry ate promising raw materials for production of charcoal. Studies performed at the Latvian State Institute of Wood Chemistry have demonstrated that engine oil refinery acid tar (EORA tar) is a good catalyst of wood carbonisation. Charcoal yield can be increased by 20 to 54 % in comparison with that in the case of non-catalysed pyrolysis charcoal. 

The Lewis and Bronsted acids lower the starting temperature of wood decomposition and charcoal formation and along with an increased char formation, diminish the yield of some volatile products of pyrolysis. The latter fact is an undesirable i enomenon if an energetic self-sufficiency in the carbonisation of wood is striven for (10), Therefore, the objective of the present investigation was to elucidate not only the effect of different available catalysts upon the yield of charcoal, but also that on the yield of volatile products. 

The main drawback is the formation of methyl-2 butene-1 yne-3, 3, leading to rapid deactivation of the catalyst by carbonisation. All attempts to reduce the formation of 3 failed and the reaction 1 —> 2 is specific for prenal 2 and not generalizable to other substrates like dimethylvinylcarbinol or dehydrolinalol. 

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