Cyclone reactor, experiments

The manner of heat transfer is unusual, as this reaction cyclone is solar-heated. In any other cases, the carrier gas (e.g., nitrogen or product gas from the fast pyrolysis) must be preheated, because the heat transfer by direct contact of the particles to the cyclone wall is poor and only sufficient to keep the reactor at adiabatic conditions. Lede built two different cyclone reactors for experiments on the fast pyrolysis of... 

This paper presents an outline of the main ideas and results illustrating the fusion like behaviour of biomass pyrolysis. The ablative pyrolysis rate of wood rods applied on a hot spinning disk or on a stationnary heated surface is studied. The observations are quite similar to those made in the same conditions with rods of true melting solids (ice, paraffin,. ..) in agreement with a theoretical approach. The "fusion temperature of wood is found close to 739 K in agreement with a limited number of experiments of wood sawdust fast pyrolysis in a hot cyclone reactor. The results show also that in most of the experimental devices, the direct measurement of wood pyrolysis reaction rate constant is impossible above about 800 K. 

Nearly every cat cracker experiences some degree of coking/fouling. Coke has been found on the reactor walls, dome, cyclones, overhead vapor line, and the slurry bottoms pumparound circuit. Coking and fouling always occur, but they become a problem when they impact throughput or efficiency. 

In all experiments, gases, liquids, water fraction as well as solid residue were obtained as products and analyzed on different capillary GC columns and registered with TCD-and FID-detectors. The reactor sand used and the fillers in the overflow and cyclone were combusted in a furnace at 810°C to constant weight. The loss in weight was balanced as carbon black. 

Two experiments (RSI, RS2) were performed with DC-II and Swedish wheat straw with particle size in the range of 1 to 2 mm. During these experiments the solids recovery system (cyclone and impinger, Figure 1) did not perform satisfoctorily with the very fragile straw char. The char, exposed to the very harsh envirorunent (fast moving sand particles) of the CFB reactor and atritted to very fine particles, almost submicTon powder, could not be collected by conventional solids recovery systems. Consequently, the char was either adhered with the liquids heavy fraction to the STHE inner tubes or readilly accumulated in the liquid recovery system. 

Particles are the bed material employed in fluidized bed reactors and can be reactants (e.g., coal and limestone), products (e.g., polyethylene), catalysts, or inert. The choice of particle size, in general, affects the hydrodynamics, transport processes, and hence the extent of reactor conversion. Particles experience particle particle collisions, friction between particles and walls or internals, and cyclones. In some cases, the catalyst material is inherently susceptible to attrition, and special preparation to enhance the attrition resistance is required. For example, the vanadium phosphate metal oxide (VPO) catalysts developed for butane oxidation... 

C with a mixture of SO3 and nitrogen containing 10 mol %S03 (typical for our experiments in cyclone and tube reactor) in a conventional bubble column. In our stirred cell sulfonation experiments, k was found to be a factor of 10 lower than the value 1.2 10 [m/s] used in calculating Table I. Therefore Ha 1 -I- Dg g /zD m(c )Q in the stirred cell. This means that the reaction is instantaneous with respect to mass transfer in that reactor. 

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