Densification system

The following must be borne in mind when considering densification (a) Solutions are always specific to a particular material, site and end use. (b) The use of a given residue is always affected by the material it can replace or the availability of other residues and many special crops or products competing in the same market, (c) Selection of densification systems must take into account the entire process from production of the residue to its delivery and use in its final form, (d) Physically handling a residue will account for higher costs and more energy than the individual densification systems. 

The overall energy efficiency of densification systems may be misleading. Only 10 to 25of input energy is lost in making a biomass fuel pellet, even if electrical energy is thermally generated from the same residue when used as feedstock. 

A low cost system for smaller communities is shown in Figure 1. It consists of a shredder to reduce the size of waste paper, a densification system to convert the shredded waste paper to a dense fuel "cube, the gasification reactor, a gas cleanup system, and an engine-generator to convert the gas to electrical power. 

The simplest type of densification system consists of a shredder followed by an agricultural type "cubing machine. These machines were originally built to produce densified animal feeds, but can be modified easily to produce solid waste fuel cubes. One of the first systems of this type was operated during the early 1970 s in Fort Wayne, Indiana, to produce a solid waste fuel for the city power plant (4). A more recent application of densification was demonstrated by the Papakube Corporation of San Diego, California, which manufactures solid waste cubes as a boiler fuel (5). 

Solid waste shredding and densification system Downdraft Gasifier... 

If such undesirable performance occurs often and disrupts the operation of the granulation and densification system excessively, the air used for fluidization must be processed to achieve constant moisture content and, possibly, also constant temperature. The best conditions should be determined in an optimization step and then kept at all times. 

Effects of particle size and pressure on the reactive sintering were studied by Gobran et al. (2004). The synthesis of RuAl was described it was observed that reactive systems containing low-melting constituents such as aluminium are assisted in densification by the formation of a transient liquid phase. Reactive sintering using... 

Sintering and Densification. Recall from Section 2.2.2.4 that sintering is the consolidation of particles during heat treatment, and that it is controlled by the reduction in free energy of the system that accompanies surface area elimination during densification. Since the thermodynamics of sintering have already been described, we... 

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