Environmental Engineering Reference
In-Depth Information
Figure 10.7.
Integration of CCS using BLGCC.
sources and climate change mitigation, the bioenergy systems with CCS (BECCS) could result
in reduction of greenhouse gases from the atmosphere at economically feasible mitigation cost
(IPCC, 2006).
The net CO 2 emissions in the pulp industry mainly come from different sources: (i) On-site
CO 2 emissions from fossil fuels, (ii) CO 2 emissions from fossil fuel used for purchased electricity
generation, (iii) CO 2 emissions from fossil fuels to extract, manufacture and transport feed-
stocks. In addition, CO 2 emissions in large quantities come from biomass combustion. There are
opportunities for CO 2 mitigation in the pulp industry and significant research has estimated the
considerable potential to reduce CO 2 emissions from fossil fuel consumption and electricity in
pulp mills based on the most efficient existing technologies.
10.5.1 BLG systems with CCS
Figure 10.7 shows an example of a bioenergy polygeneration system integrated with CCS using
a black liquor gasification combined cycle (BLGCC). Larson et al . (2003, 2006) investigated
environmental benefits of black liquor gasification technology for electricity production as a
replacement for conventional recovery boilers integrated with a reference mill producing about
6 million lbs. per day of black liquor solids (BLS). The electricity generation could result in
significant reductions in net CO 2 emissions than the recovery boiler case and the BLGCC systems
in United States has potential to reduce up to 35 million tonnes net CO 2 emissions and 160,000
tonnes net SO 2 emissions and 100,000 tonnes net NO x emissions within 25 years (Larson et al .,
2003). However, the net CO 2 emissions from black liquor gasification based biofuel production
are larger than the recovery boiler system due to additional biomass consumption to compensate
for the total energy deficit (Larson et al ., 2006).
The potential of CO 2 emissions reduction could be achieved if hydrogen is produced from
black liquor gasification and using hydrogen as transport fuel replacing gasoline (Andersson and
Harvey, 2006). About 59,000 tonnes per year of hydrogen could potentially be produced, reducing
about 830,000 tonnes per year of CO 2 if integrated with a reference mill producing 630,000 air-
dried tonnes per year of pulp. About 60% of Sweden's domestic gasoline could be replaced with
hydrogen if all black liquor from market pulp mills in Sweden was converted to hydrogen, which
could have resulted in a reduction of about 8%of CO 2 emissions in Sweden in 2006. The hydrogen
production with CCS resulted in about 1 million tonnes per year of CO 2 reduction.
The potential and economic feasibility of CCS in the Swedish pulp and paper industry was
studied by Möllersten et al . (2003a, 2003b, 2004), which showed a potential of about 6 million
tonnes of CO 2 reductions per year, equivalent to about 10% of Swedish net CO 2 emissions from
black liquor gasification integrated with pre-combustion CO 2 capture. The integration of black
liquor gasification and CCS with large pulp and paper mills could result in capture of a large
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