Pyrolysis of solid fuels

Saastamoinen J.J. and Richard J.R., The Simultaneous Drying and Pyrolysis of Solid-Fuel Particles , Combustion and Flame 106, 288-300(1996)... 

Saastamoinen J. and Richard J. R.(1996) Simultaneous drying and pyrolysis of solid fuel particles. Combuston and Flame, 106, 288-300... 

Endothermic zeroth order pyrolysis of solid fuel and dissociative sublimation of AP to ammonia and perchloric acid... 

Lincoln, K.A., Flash-Pyrolysis of Solid-Fuel Materials by Thermal Radiation, Pyrodynamics, 2, 133-143, Gordon and Breach, No. Ireland. (1965)... 

One of the research projects at the Department of Apparatus Design and Particle Technology is the investigation of the pyrolysis of solid fuels (biomass, coal). Due to the high water content of some of these fuels the initial drying process of the solid material is an important step of the whole pyrolysis process. 

J. Petek, H.J. Schoegler et al.. Drying and Pyrolysis of Solid Fuels, poster session, VGB symposium power plants, Essen, BRD, 1995 B. Rummer, Trocknungsmodell fuer ein poroeses Feststoifpartikel, thesis, Graz University of Technology, 1994... 

Jess, A. (1996a) Mechanisms and kinetics of thermal reactions of aromatic hydrocarbons from pyrolysis of solid fuels. Fuel, 75, 1441-1448. 

Fig. 2. Overall schematic of solid fuel combustion (1). Reaction sequence is A, heating and drying B, solid particle pyrolysis C, oxidation and D, post-combustion. In the oxidation sequence, left and center comprise the gas-phase region, tight is the gas—solids region. Noncondensible volatiles include CO, CO2, CH4, NH, H2O condensible volatiles are C-6—C-20 compounds oxidation products are CO2, H2O, O2, N2, NO, gaseous organic compounds are CO, hydrocarbons, and polyaromatic hydrocarbons (PAHs) and particulates are inerts, condensation products, and solid carbon products.

At present there is no small-scale test for predicting whether or how fast a fire will spread on a wall made of flammable or semiflammable (fire-retardant) material. The principal elements of the problem include pyrolysis of solids char-layer buildup buoyant, convective, tmbulent-boundary-layer heat transfer soot formation in the flame radiative emission from the sooty flame and the transient natme of the process (char buildup, fuel burnout, preheating of areas not yet ignited). Efforts are needed to develop computer models for these effects and to develop appropriate small-scale tests. 

This review defines the thermochemical conversion processes of solid fuels in general and biofuels in particular that is, what they are (drying, pyrolysis, char combustion and char gasification) and where they take place (in the conversion zone of the packed bed) in the context of the three-step model. 

The thermochemical conversion of solid fuels is a complex process consisting of drying, pyrolysis, char combustion, and char gasification. 

The thermochemical conversion of solid fuels, in the context of PBC systems takes place, in the conversion system, and more precisely in the conversion zone. The thermochemical processes are drying, pyrolysis, char combustion, and char gasification. The conversion process is promoted by the exothermic char combustion reactions. 

When authors illustrate the subject of thermochemical conversion of solid fuels in the literature, the conversion zone in a packed bed is divided into different process zones (drying zone, pyrolysis zone, char combustion zone, and char gasification zone), one for each thermochemical conversion process. The spatial order of this process zones is herein referred to as the bed process structure or conversion process structure. The conversion process structure is a function of conversion concept. Even more important, the bed process structure can only exist in the diffusion controlled conversion regime when the conversion zone has a significant thickness. 

Another cleaner alternative consists in producing solid, liquid and gaseous fuels by pyrolysis. The solid fuel could be upgraded by mechanical separation of metals and minerals in order to produce a cheap feedstock to a classical gasifier. Moreover, selected additions during pyrolysis could entrap pollutants such as chlorine and heavy metals [1-3]. 

C. Pasel and W. Wanzl, Pyrolysis of shredder waste - reaction behaviour and product formation compared to thermochemical behaviour of solid fuels, Erdol Erdgas Kohle, 9, 449-454 (1998). 

Biomass combustion is a complicated process involving drying of solid fuel, pyrolysis and oxidation of pyrolysis gases and carbon. Many modelling studies to describe combustion performance have been based on these three stages (4, 5, 14, IS). In order to further investigate the effects of biomass characteristics on the observed combustion performance, a simple stoichiometric model for wet biomass combustion was employed to describe the overall reaction process (Eqn. 3) 15). An empirical mole of biomass is arbitrarily normalised to one atom of carbon by the formula C H Oj. 

At VTT, the following issues are addressed in the present study pyrolysis of solid biomass [3, 4], hot vapour filtration, pyrolysis oil quality [5] and fuel oil specifications [6], storage and handling properties of pyrolysis oil, boiler applications [7], and techno-economic assessment of pyrolysis systems [8]. A considerable amount of work... 

Razina, G.N., Fedoseev, S.D., Gvozdarev, V, Staroverov, VA. (1976), Influence of Gas-Dynamic Factors on the Gas-Phase Products of Coal Pyrolysis in Conditions of Plasma Temperatures, in Modern Processes of Conversion of Solid Fuels, Adv. of Moscow Institute of Chemical Engineering (Mendeleev University), vol. 91, p. 94, Moscow. 

Decaborane is the most studied of all the polyhedral boranes and at one time (mid-1950s) was manufactured on a multitonne scale in the USA as a potential high-energy fuel. It is now obtainable in research quantities by the pyrolysis of B2H9 at 100-200°C in the presence of catalytic amounts of Lewis bases such as Me20. B10H14 is a colourless, volatile, crystalline solid (see Table 6.2, p. 163) which... 

A combination of pyrolysis and gasification is applied to produce hydrogen from solid fuels. In the past, a variety of methods has been used to gasify solid fuels, to... 

Investigators have used the words carbon and soot to describe a wide variety of carbonaceous solid materials, many of which contain appreciable amounts of hydrogen as well as other elements and compounds that may have been present in the original hydrocarbon fuel. The properties of the solids change markedly with the conditions of formation and, indeed, several quite well-defined varieties of solid carbon may be distinguished. One of the most obvious and important differences depends on how the carbon is formed carbon may be formed by a homogeneous vapor-phase reaction it may be deposited on a solid surface that is present in or near the reaction zone or it may be generated by a liquid-phase pyrolysis. 

It has been observed that solid oxide fuel cell voltage losses are dominated by ohmic polarization and that the most significant contribution to the ohmic polarization is the interfacial resistance between the anode and the electrolyte (23). This interfacial resistance is dependent on nickel distribution in the anode. A process has been developed, PMSS (pyrolysis of metallic soap slurry), where NiO particles are surrounded by thin films or fine precipitates of yttria stabilized zirconia (YSZ) to improve nickel dispersion to strengthen adhesion of the anode to the YSZ electrolyte. This may help relieve the mismatch in thermal expansion between the anode and the electrolyte. 

---