Maximum liquid yields temperature effects

Temperature and Product Yields. Most oil shale retorting processes are carried out at ca 480°C to maximize liquid product yield. The effect of increasing retort temperature on product type from 480 to 870°C has been studied using an entrained bed retort (17). The oil yield decreased and the retort gas increased with increased retorting temperature the oil became more aromatic as temperature increased, and maximum yields of olefinic gases occurred at about 760°C. Effects of retorting temperatures on a distillate fraction (to 300°C) are given in Table 6. 

Table 4 summarizes the results of the liquid yield and conversion from SCFE of Butia coal with pure toluene at 623 K and at 3, 4 and 5 moLl 1 solvent density. The liquid yield and conversion figures are again lower than those reported in the literature for different coals. The conversion reached a maximum at 4 mol.1 1 this effect has been shown in the literature [8], though at higher pressures. More investigation is being carried out to clarify this effect. Since the experiments were accomplished at constant temperature - assuring the same depolymerization/thermolysis of the coal structure, the increase in the liquid yield and conversion could be attributed to an enhancement in solvent density (solvent power). 

The influence of pyrolysis temperature on the products yields was studied using mixtures of wood biomass wiA plastic (from 2 1 to 2 1 in weight ratio). The conversion degree did not change significantly with temperature variation as it was noted by other researches. Fig. I shows the main effect of temperature increase for pine wood / polyethylene co - pyrolysis within the range 360 C - 460 C is the higher amount of gas formed, whilst water fraction yield was decreased. The maximum yield of liquids (50 wt.%) was obtained at 370-400 C. 

The maximums of liquid product yields (80 and 52.5 mass% in modes 1 and 2, respectively) were observed at the same dose values of about 6 kGy. However, gasoline fractions produced in the two modes considerably differed in their hydrocarbon contents. At the temperature of 375°C, isoalkane yields were comparable with those observed in the catalytic process at the temperatures above 600°C. The unusually high yields of isoparaffins in the RTC modes characterized by relatively low values of temperature and dose rate were attributed to the effects of energy transfer from paraffin to aromatic components of the hydrocarbon mixture. 

Some effort has recently been made to study copyrolysis of wood biomass and polyolefins.The effects of reaction temperature, wood-polymers mixture composition, and catalysts on the mixture s conversion into liquids and gases were established and discussed. The optimum temperature of wood—plastic mixture conversion, which corresponded to the maximum total liquid products yield, was close to 400°C. In the cohydropyrolysis processes the non-additive increase of the wood—plastic mixture conversion degree and of the distillable fractions yields took place as a result of the chemical interaction between radical fragments of wood and the thermal decomposition of polyethylene. 

Because forced-convection loops are costly to construct, it is now the usual practice to operate the loops as permanent testing facilities, with corrosion specimens cycled in and out of the facility. Test specimens of various materials are generally placed in the hot leg, and the effect of the flowing liquid on the specimens is determined from changes in weight, dimensions, composition, mechanical properties, and microstructure. Such an approach yields data on maximum corrosion rates as a function of temperature and liquid metal flow rate. Any attempt to elucidate corrosion mechanisms, however, is hampered by the inability to interrelate dissolution and deposition processes. 

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