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29 Zero-Waste Biorefineries for Circular Economy

Circular economy

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Figure 29.1

Schematic representation of the

process involved in circular economy concept.

used to its fullest ability. Therefore, this write-up follows a holistic approach that

can target atmospheric CO2 removal and storage by utilizing biologically degradable

waste. This creates a win-win sustainable solution from all ends. (Figure 29.1) [6].

29.2

Bioenergy, Bioeconomy, and Biorefineries

Growing bioeconomy manages to provide required elements for the overall global

sustainability transition which includes biological processes and bio-based product

dependency [7]. The overall agenda of the bioeconomy is to simply substitute

fossil fuel economy with sustainable bioeconomy and simultaneously mitigate

out the dependency of countries on the natural economy [8]. The compatibility

of sustainable bioeconomy with a circular economy aims to use across all its

different uses with minimal waste and optimal valorization of biomass. The two

closely related priorities of bioeconomy are biofuel and biorefineries. Biorefineries

being the fundamental technology can diminish reliance on petroleum-based

refineries. However, bio-based products and bioenergy are the principal products of

bioeconomy [9]. Bio-based transport fuels can be categorized into first-generation,

second-generation, and third-generation biofuels. Among all, third generation is at

the initial growth phase of the development (Table 29.1) [6].

Biorefinery being at the early R&D phase facilitates biomass conversion to pro-

duce fuel, power, heat, and therefore, maximizes the value derived from biomass

feedstock (Figure 29.2) [17]. The high value-added product increase profitability

and high-value fuels achieve energy demand at low power production. This reduces

greenhouse gas (GHG) emissions from the traditional power plant facilities [18].

Bioenergy can be considered as carbon neutral, as during combustion released car-

bon dioxide is assumed to be compensated by the CO2 which is absorbed by the

tree during its growth [19]. However, the sustainability of using wood as an energy

source is still questioned due to the long regeneration cycle of forest biomass [19].

There might be competition in bioenergy with the food sector directly. Therefore,

maximizing resource efficiency is our ultimate agenda till 2050. This could be done

by the utilization of wood biomass to decrease fossil fuel and energy potential to be

utilized at the end of the cascaded life cycle (Table 29.2) [23].