Using microwave technology for the treatment of MSW, the issue of long heating
periods energy lost to the environment and thermal gradients are minimised because
the materials are heated from outside and inside different from the conventional
heating as shown in Fig. 7. For the treatment of biodegradables in the MSW stream,
since thermal and non-thermal impacts are created in the materials, this will lead to
the rupturing of the crystalline structures of the lignocellulosic materials, thereby
enhancing the reactivity of the materials.
The major advantages of using this technology include reducing the volume of
wastes, selective heating of the wastes and ability to treat the waste in situ. Recent
results on the use of this technology in biodegradable waste treatment show that
1 tonne of waste can produce reasonable barrels of oil, with a reasonable amount of
carbon black. The oil generated can be used in the generation of green electricity and
many other applications.
3.4 Biorefinery (Bioconversion)
Biorefinery (bioconversion) technology converts organic wastes or biodegradable
fraction of the MSW to chemicals using the anaerobic digestion. This technology
converts the biodegradables from the MSW to varieties of marketable products that
can be used to generate fuels, chemicals, and fibres [29, 30]. The concept of the
biorefinery is not different from the conventional refinery process which produces
multiple fuels and products from crude oil as starting product. Biorefinery process
utilises biomass from the municipal solid wastes for conversion to liquid and
gaseous biofuels. Generally, in biorefinery facilities, the organics fractions of the
MSW are usually converted into biogas, while the non-organic components are
converted into solid refuse fuels (SRF) used in syngas production. Starting from
the syngas, the fuel synthesis facilities such as in Fig. 8 will convert the syngas
various fuels such as bio-jet fuel, bio-diesel, bio-ethanol, bio-methanol, dimethyl
ether, etc. which can be used for various energy applications. It is worth noting that,
in the process of syngas production from the SRF, several thermochemical steps are
involved at different temperatures ranging from torrefaction, gasification and
pyrolysis.
As depicted in Fig. 8, a sustainable biorefinery configuration must produce
bio-products in conjunction with bioenergy and biofuels. To maximise the efficiency
of the biorefinery process, most of the advanced biorefinery facilities are usually
integrated with efficient and flexible biomass feedstock conversion systems which
involves a combination of physical, chemical, biochemical, and thermochemical
processes for the production of multiple products from the biomass. This technology
is recognised as one of the most promising technologies for the effective implementation of modern sustainable energy policies, especially in the transportation sector.
Although biorefinery offers environmental benefits, it is important to consider
prevention of biodiversity loss during the conception of a biorefinery by utilising
188
A. A. Gado et al.
periods energy lost to the environment and thermal gradients are minimised because
the materials are heated from outside and inside different from the conventional
heating as shown in Fig. 7. For the treatment of biodegradables in the MSW stream,
since thermal and non-thermal impacts are created in the materials, this will lead to
the rupturing of the crystalline structures of the lignocellulosic materials, thereby
enhancing the reactivity of the materials.
The major advantages of using this technology include reducing the volume of
wastes, selective heating of the wastes and ability to treat the waste in situ. Recent
results on the use of this technology in biodegradable waste treatment show that
1 tonne of waste can produce reasonable barrels of oil, with a reasonable amount of
carbon black. The oil generated can be used in the generation of green electricity and
many other applications.
3.4 Biorefinery (Bioconversion)
Biorefinery (bioconversion) technology converts organic wastes or biodegradable
fraction of the MSW to chemicals using the anaerobic digestion. This technology
converts the biodegradables from the MSW to varieties of marketable products that
can be used to generate fuels, chemicals, and fibres [29, 30]. The concept of the
biorefinery is not different from the conventional refinery process which produces
multiple fuels and products from crude oil as starting product. Biorefinery process
utilises biomass from the municipal solid wastes for conversion to liquid and
gaseous biofuels. Generally, in biorefinery facilities, the organics fractions of the
MSW are usually converted into biogas, while the non-organic components are
converted into solid refuse fuels (SRF) used in syngas production. Starting from
the syngas, the fuel synthesis facilities such as in Fig. 8 will convert the syngas
various fuels such as bio-jet fuel, bio-diesel, bio-ethanol, bio-methanol, dimethyl
ether, etc. which can be used for various energy applications. It is worth noting that,
in the process of syngas production from the SRF, several thermochemical steps are
involved at different temperatures ranging from torrefaction, gasification and
pyrolysis.
As depicted in Fig. 8, a sustainable biorefinery configuration must produce
bio-products in conjunction with bioenergy and biofuels. To maximise the efficiency
of the biorefinery process, most of the advanced biorefinery facilities are usually
integrated with efficient and flexible biomass feedstock conversion systems which
involves a combination of physical, chemical, biochemical, and thermochemical
processes for the production of multiple products from the biomass. This technology
is recognised as one of the most promising technologies for the effective implementation of modern sustainable energy policies, especially in the transportation sector.
Although biorefinery offers environmental benefits, it is important to consider
prevention of biodiversity loss during the conception of a biorefinery by utilising
188
A. A. Gado et al.