BIOREFINERY: TECHNOLOGIES AND PERSPECTIVES

Autores: B. Bruce Sithole¹

¹Director & Chief Scientist, Biorefinery Industry Development Facility,

Council for Scientific & Industrial Research, Durban, South Africa

¹Professor, Discipline of Chemical Engineering, College of Agriculture & Engineering Sciences, University of KwaZulu-Natal, Durban, South Africa. Email: bsithole@csir.co.za; sitholeb1@ukzn.ac.za

 

Depletion of fossil fuels and the environmental concerns related to their use, ogether with increased energy demands and the need for cleaner production technologies across all industries is providing strong impetus in the search for alternative and renewable raw material resources. Our fóssil driven economy has resulted in many challenges for the earth including increased greenhouse gas emissions, climate change and global warming. To promote sustainable growth with minimal environmental impact, alternate and renewable resources need to become an important part of the feedstock raw material for many of our industrie. Currently the Forestry, Timber, Pulp and Paper (FTPP) sector is wasteful and has limited products as illustrated the in Figure 1. For example, the sector extracts only about 47% value from trees with the majority of trees being lost as waste . At the same time, there is ever-increasing pressure on the industry to make changes, improvements and/or adaptations to their processes in order to achieve cleaner production technologies that are more environmentally friendly. The disposal of their waste by-products in an economically and environme tally acceptable manner is another critical issue facing the FTPP sector. This is mainly due to challenges in locating disposal works and complying with environmental requirements imposed by waste m nagement and disposal regulations. For example, sawmills produce large volumes of sa dust and other tree trimmings such as bark, leaves and branches. Pulp and paper mills, in addition to the aforementioned waste streams, also generate large quantities of process waste by-products in the form of sludge, dregs and fly ash. These by- products are traditionally stock-piled on site, landfilled, or burned. However, according to environmental regulations, these practices are being curtailed as they are environmental hazards that generate greenhouse gases and can lead to possible leaching of toxic chemicals into surrounding ground and water sources . In the case of landfilling as a means of waste disposal, significant costs are incurred by industry for transporting waste to landfill sites, maintaining landfill sites, and establishing new landfill sites once the previous ones are full. The problem is further compounded by the fact that suitable land for landfilling in relatively close proximity to where the waste is generated is limited. Disposal of organic waste (including food waste) to landfill is outlawed in many countries including Germany, Sweden, Canada; and diversion of organic waste from landfill is now also a priority in South Africa. Opportunely, the waste streams generated by the FTPP sectors is composed of potentially high value products and finding alternative and innovative uses for these industry waste streams and diverting them from landfill will transform the face of the FTPP industries, both economically and environmentally (as illustrated in Figure 2). The overall objective of bio refinery research and development is therefore to contribute to the evolution of FTPP mills into forest biorefineries through innovative biorefinery technologies, and in so doing, revitalise industrial development opportunities within this renewable biomass processing sector, whilst at the same time mitigating some of its environmental impacts. This will ensure that the industry stays abreast of new environmental and technological developments in order to remain internationally competitive and economically sustainable. Increased revenue streams from the production of new bio-materials and chemicals would ensure preservation of infrastructure, jobs, supply chains and permits, whilst at the same time helping countries minimise their energy problems and environmental impacts. The R&D on biorefinery Technologies directly addresses some of the challenges associated with transitioning to a green economy and proper implementation of the technologies can result well over 90% tree utilisation as illustrated in Figure 2. Biorefinery technologies can be effected via three modes, namely thermal, chemical, and biochemical fractionation as illustrated in Figure 3.

 

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