Pyrolysis, flash liquid chemicals

GC = gas chromatography, Py = pyrolysis (flash or hydrous heating), MS = mass spectrometry (HR = high resolution), IRMS = isotope ratio mass spectrometry, HPLC = high-pressure liquid chromatography, EC = electron capture. Cl = chemical ionization, NMR = nuclear magnetic resonance spectrometry. X-ray = X-ray crystallography. 

Liden, A.G., Berruti, F., Scott, D.S., 1988. A kinetic model for the production of liquids from the flash pyrolysis of biomass. Chemical Engineering Commimications 65 (1), 207—221. 

The results of low-temperature matrix-isolation studies with 6 [41a] are quite consistent with the photochemical formation of cyclo-Cif, via 1,2-diketene intermediates [59] and subsequent loss of six CO molecules. When 6 was irradiated at A > 338 nm in a glass of 1,2-dichloroethane at 15 K, the strong cyclobut-3-ene-1,2-dione C=0 band at 1792 cm in the FT-IR spectrum disappeared quickly and a strong new band at 2115 cm appeared, which was assigned to 1,2-diketene substructures. Irradiation at A > 280 nm led to a gradual decrease in the intensity of the ketene absorption at 2115 cm and to the appearance of a weak new band at 2138 cm which was assigned to the CO molecules extruded photo-chemically from the 1,2-diketene intermediates. Attempts to isolate cyclo-Cig preparatively by flash vacuum pyrolysis of 6 or low-temperature photolysis of 6 in 2-methyltetrahydrofuran in NMR tubes at liquid-nitrogen temperature have not been successful. 

Efficient technology could also be developed based on catalytic biomass pyrolysis for the conversion of biomass into clean and renewable liquid bio-oil. This would facilitate its introduction into the energy market as a renewable fuel or as source of high value chemicals. It is possible to produce stable liquid biofuels from biomass flash pyrolysis, in a single stage catalytic process, although further developments are necessary. 

Pyrolysis of biomass is divided into slow pyrolysis, which is well known to produce charcoal, for example, fast pyrolysis, which produces a high yield of liquid biofuels and other chemicals (Bridgwater, 2000) and flash pyrolysis. Slow pyrolysis (or carbonisation) requires low temperatures and very long residence time. In the carbonisation process the amount of char is maximised. 

The liquids require a hydrorefining step to stabilize their reactive properties, to reduce the asphaltenes and preasphaltenes, to reduce sulfur, nitrogen, and oxygen, and to make the liquids more distillable. The extent of hydrorefining depends on the end use of liquids—fuel oil or chemical feedstocks. The objective of this work is to evaluate the hydrorefining processibility of ORC flash pyrolysis coal tar as a part of the tar characterization task. Results of the initial phase of catalyst screening tests are reported in this chapter. 

The quality of the product is of primary importance in developing a recycling technology converting plastics into fuels by pyrolysis. Today the characterization of a liquid fuel from any sources is obviously based on the qualification methods and standards of fuels from mineral oil. The properties of the pyrolysis-derived fuels from plastics are expected to be similar to conventional fuels (energy content, viscosity, density, octane and cetane number, flash-point, etc.). However, in addition to the familiar ranking values it is necessary to know more about the chemical composition of the plastic pyrolysis oil, because of the peculiarities as follows ... 

The complexity arises from the degradation of lignin, cellulose, hetnicellulose and any other organics in the feed material, giving a broad spectrum of phenolic and many other classes of compounds that result from uncontrolled degradation as described below. The liquid from fast or flash pyrolysis has significantly different physical and chemical properties compared to the liquid from slow pyrolysis processes, which is more like a tar. 

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