Thermal from hydropyrolysis

Table I. Comparison of Product Distribution from Hydropyrolysis (HP) and Thermal Cracking (TC) of -Hexadecane (1)° °...

The differences in liquid product composition from the two types of processes are even more pronounced. The major liquid products (see Table V) from hydropyrolysis of 2 at 550°C are C6-Ci0 cyclohexenes and cyclohexanes, and C5-C8 open-chain hydrocarbons, while in thermal cracking the main liquid product at this temperature is 1,2,3,4,5,6,7,8-octahydronaphthalene. At 600°C a much higher conversion of 2 into C5—C10 aliphatic products is observed in the hydropyrolysis Experiment 25, whereas in the thermal cracking Experiment 26 there is much higher formation of aromatic products, i.e., benzene, toluene, ethylbenzene, and... 

Chapters 10-12 cover important aspects of coke formation in metal tubular reactors during pyrolysis of hydrocarbons. Chapters 13 and 14 are concerned with coal and lignite pyrolysis. Chapters 15 and 16 deal with pitch formation from, respectively, heavy petroleum fraction and tar sand bitumen. Chapters 17 and 18 cover studies on the mechanisms of thermal alkylation and hydropyrolysis. Chapters 19 and 20 on oil shale deal with the properties of oil shale and shale oil as developed by techniques of microwave heating and thermal analysis. 

Mechanism of Hydropyrolysis of -Paraffins. The hydrogen carbon ratio in the total hydropyrolysis product from 1 is higher (H C > 2.2) than that in 1 itself (H C = 2.12) in all experiments performed (Tables II and III). This clearly indicates participation of hydrogen in the process. To account for the observed differences between hydropyrolysis and conventional thermal cracking (Table I), and to rationalize the variations in product composition as a function of reaction conditions,... 

Hydropyrolysis process gives the higher degree of mixture conversion and higher yield of light liquids as compare to pyrolysis in an inert atmosphere. Observed in some cases non-additive effects indicate that the interaction between wood and plastic derived products takes place during mixture thermal treatment. The more pronounced synergistic effects were detected for hydropyrolysis process. Iron catalysts promote the formation of liquid hydrocarbons from biomass/plastic mixtures and influence on their coit sition. 

The reactions taking place during hydropyrolysis are probably dominated by free radical chemistry. Catalytic effects from reactor components or trace minerals found in the feedstocks cannot, however, be discounted. Cracking reactions are probably initiated through thermally induced unimolecular bond scission. 

The subsequent reactions involving the free radicals are those which distinguish hydropyrolysis from thermal reactions in the absence of high hydrogen pressure. Shabtai, et al. (5) have postulated the reaction... 

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