08.08.2015   Biofuels and Bioenergy

Technologies for Conversion of Waste to Energy and Products

As mentioned before, the technologies for the conversion of waste to energy and products can be broken down into three categories: thermochemical, biochemical, and physicochemical technologies. Combustion/incineration is a special type of thermochemical technology which is mainly used for the generation of heat and electricity. As indicated earlier, various types of upgrading technologies are used to generate transportation fuels, chemicals, and materials [10]. The end results for the applications of these technologies are heat, electricity, transportation fuel, chemicals, or materials. In the fol­lowing sections, we briefly evaluate each of these technologies. Some of the detailed descriptions of the combustion, pyrolysis, gasification, and plasma technology outlined below closely follow the excellent review of Helsen and Bosmans [7].

TABLE 6.2

Summary of Advantages and Disadvantages of Various Biomass Pretreatments

Biomass

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Pretreatment Advantages

(Continued)

Summary of Advantages and Disadvantages of Various Biomass Pretreatments

TABLE 6.2 (CONTINUED)

Biomass

Pretreatment

Advantages

Disadvantages

Torrefaction

Possibility for utilization of coal infrastructure for feeding and milling.

Improved hydrophobic nature — easy and safe storage, biological degradation almost impossible.

Improved grinding properties resulting in reduction of power consumption during sizing.

Increased uniformity and durability.

No commercial process. Torrefied biomass has low volumetric energy density.

TOP process

Combines the advantages of torrefaction and pelletizing.

Better volumetric energy density leading to better storage and cheaper transportation.

Desired production capacity can be established with smaller equipment.

Easy utilization of coal infrastructure for feeding and milling.

No commercial process.

Does not address the problems related to biomass chemical propertied, that is, corrosion, slagging, fouling, sintering, or agglomeration.

Source: Modified from Shah and Gardner, in press. Biomass Torrefaction: Applications in Renewable Energy and Fuels. In Encylopedia of Chemical Processes, Boca Raton, FL: CRC Press.

Note: This information is repeated in Table 7.6.