Pelletization

The pelletizing of Waste and Green Refuse is one of the essential ‘enabling first steps’ to beneficiate or recycle wastes for further use. The latter is one of iLive‘s recent projects. In this project iLive conducted successful technology trials on green waste pelletization supplied by municipal solid waste, mainly garden waste. Densification via pelletizing technologies allows biomass to be used, handled and transported economically as a feedstock for biomass-to-energy supply chains. Biomass pellets could be used to substitute coal at power stations (to produce green electricity), Coal-to-Liquid plants (to produce biofuels) or fuel wood fired cooking stoves for domestic use. The next project aim is to divert around 120,000 tons of green waste per annum from landfills to a commercial pelletizing facility.

Pretreatment is a first crucial step to modify the structure of wood via physical, chemical, and biological treatment for cost effective and sustainable fuels and chemicals production. Different pretreatments would be selected to upgrade the characteristics of wood with respect to different applications and process efficiencies. High-temperature pretreatment (e.g., torrefaction) at the temperature range greater than 250 °C led to higher degradation rate of sugars and extractives, which is not preferable for fuel and chemicals production from lignocellulosic biomass. Instead, high-temperature pretreatment was used to upgrade the solid fuel for thermochemical conversion (e.g., combustion and gasification). It can remove the moisture and volatiles with a low-heating value of the native biomass, which favors for the ease of fuel combustion compared to the raw wood. In addition, it can increase the hydrophobicity of the biomass which improves their handling and storage performance. In this chapter, the production chain of the wood pellet production with incorporating recent novel pretreatment technologies (torrefaction, steam explosion, and hydrothermal carbonization) were discussed. The resulted pellets are a uniform feedstock for producing chemicals, heat, and energy via biochemical and thermochemical conversion, respectively.