H2Tech - Q3 2021 - 17

SPECIAL FOCUS: HYDROGEN INFRASTRUCTURE DEVELOPMENT
Realize energy and environmental benefits
with circular H2
from waste gasification
G. RISPOLI, A. SALLADINI and A. BORGOGNA, MyRechemical, Rome, Italy;
and G. IAQUANIELLO, NextChem, Rome, Italy
Increasing concerns about environmental pollution related
to greenhouse gas (GHG) emissions is promoting the energy
transition toward more sustainable energy production systems.
These systems are based on renewable energy exploitation and
circular economy principles.
The concept of sustainability is often coupled to the concept
of waste valorization as a driver for rethinking conventional production
systems. Such vision, aiming for a more sustainable use
of resources, is also supported by the European Commission
through a policy stating that " ...waste management should be
improved and transformed into sustainable material management
with a view to promoting the principles of the circular
economy, enhancing the use of renewable energy and providing
new economic opportunities. " 1
Circular economy concept. The concept of circular economy
is redesigning many industrial fields with the aim of waste stream
valorization. In the field of solid waste, municipal and plastic
waste management is receiving urgent attention from many
governments. As a consequence of the Chinese government's
January 2018 ban on the import of waste from foreign countries,
many industries in developed countries began to face challenges
due to limited installed waste management capacity.2
At present, approximately 2 billion metric tons per year (metric
Btpy) of waste are globally produced. By 2050, this volume
is anticipated to reach 3.4 metric Btpy due to expected increases
in population and GDP, which both influence yearly waste production
value.3
standards will inevitably bring higher consumption and higher
waste production.
Both chemical production and waste disposal by incineration
imply high GHG emissions. However, combining waste
recovery and production of chemicals into one process brings
the benefits of synergy and allows for significant reductions in
overall emissions. The conversion of waste into a chemical also
simultaneously solves the issue of waste disposal and the substitution
of fossil feedstock. In this way, waste is valorized as a
source of carbon and hydrogen, representing a widely available
renewable source without geographical restrictions.
The " waste-to-chemicals " approach is also favored from an
economic point of view, as the waste feedstock becomes a source
of revenue, rather than a cost. The waste fractions that are taken
into account as sources in the waste-to-chemicals process are
indeed fractions that alternatively would have been disposed
through, at worst, landfilling or, at best, incineration with energy
This scenario may worsen as increases in living
recovery. The waste-to-chemicals process allows carbon and hydrogen
recovery-i.e., material and energy recovery.
Refuse-derived fuel (RDF), the dry fraction of unsorted municipal
solid waste (MSW) and a fraction of unrecycled, sorted
plastic waste (PW) are the types of waste eligible for the wasteto-chemicals
process. In this article, an innovative route for circular
H2
economic and environmental points of view.
High-temperature gasification for waste valorization.
Typical compositions for MSW, RFD and PW feedstocks are
reported in TABLE 1. As shown by the elementary composition,
carbon content may vary from 30 wt%-60 wt%, while H2
is in the
range of 4 wt%-7 wt%. If properly converted into syngas, then
waste may be used for the synthesis of a wide range of chemicals.4
Under this scenario, technology plays a major role in the full
implementation of a circular economy around the concept of
waste as feedstock for industrial processes. This paradigm implies
a robust and reliable technology able to manage the heterogeneous
nature of waste, as well as their pollutants content.
The proposed technology allowing the conversion of waste
into chemicals is based on a high-temperature gasification process
carried out in a pure oxygen (O2
) environment. A schematic
view of a gasifier reactor, in which such conversions are
performed, is shown in FIG. 1.
The gasifier reactor consists of three sections:
1. The melting zone on the bottom of the reactor,
where exothermic reactions and melting of
inert compounds take place
TABLE 1. Typical elementary composition of PW and RDF and
relevant LHV values
Component, wet basis
C, wt%
H, wt%
O, wt%
N, wt%
S, wt%
Cl, wt%
Moisture, wt%
Inert, wt%
LHV wet, MJ/kg
RDF
33-38
4-5
16-18
0.2-1
0.02-0.15
0.8-1.5
17-21
17-25
14-16
PW
47-61
5-7
14-20
0.2-0.5
0.02-0.3
0.8-1.5
5-9
7-20
21-24
H2Tech | Q3 2021 17
production is presented and described from technical,
H2Tech - Q3 2021

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