Page 70 - New Trends In Coal Conversion

36 New Trends in Coal Conversion

of Cansolv® technology, which is a heat-integrated SO 2 eCO 2 capture process that
uses proprietary amine solvents that are regenerated making use of the low-pressure
steam from the power plant. The project transformed the ageing 139 MW e Unit 3 of
Boundary Dam Power Station to a 115 MW e (161e162 MW e without capture) pro-
ducer of clean coal electricity. The facility has demonstrated its capability to capture
100% SO 2 emissions and 90% of carbon emissions with a purity of 99.99% CO 2 .
The issues detected during operation, fouling and plugging, caused by fly ash and
amine degradation, and leakage of the amine tank, were solved by upgrading the pro-
cess through the addition of a spray curtain to remove fly ash, the replacement of the
steam desuperheater, the introduction of a stainless steel cylinder into the original
ceramic brick amine tank, and the addition of an activated carbon unit. Current plant
availability is 84%e85% with a production capacity of 1,800 t CO 2 /d and an emission
level of 380 t CO 2 /GWh, which is below the emission limit of 420 t CO 2 /GWh (Zin-
chuk, 2017). 1 Mt CO 2 /y is dehydrated, compressed, and transported by pipeline to
Weyburn oil field for EOR and to Deadwood Formation, a saline aquifer located
near the power station, where it is injected at a depth of 3.4 km for monitoring under
the Aquistore project. Captured fly ash is sold to the concrete industry, and SO 2
captured is used for H 2 SO 4 production and sold as a valuable product. The project
has been completed with less than 6 months delay and close to the original budget,
$1.24 billion. Based on gained experience, the company believes that a likewise facil-
ity could be built for 20% or even up to 30% less (IEAGHG, 2015).
The Petra Nova Carbon Capture Project, located in W.A. Parish coal-fired genera-
tion station in Thompsons, United States, is currently the world’s largest POSTCC
facility at a power station, with a CO 2 capture capacity of 1.4 Mt CO 2 /y. Construction
has been completed on budget and on schedule. CO 2 is captured from a slipstream
(240 MW equivalent) of the flue gas of an existing coal-fired electricity generation
unit of 640 MW. CO 2 capture is carried out using the Kansai Mitsubishi Carbon Di-
oxide Recovery process (KM CDR®) that uses the proprietary KS-1 solvent, a steri-
cally hindered amine, which is regenerated using steam generated in an independent
cogeneration plant. The POSTCC unit has already demonstrated its capability to cap-
ture 90% of the CO 2 , producing 5,200 t/d of 99.9% pure CO 2 , which is delivered by
132 km of pipeline to the Hilcorp West Ranch oil field for EOR (Greason, 2017).
A 10 MW coal-fired power station in Chennai, India, is using Carbon Clean Solu-
tions’ amine-promoted buffer salt (CDRMax solvent) since October 2016 to generate
electricity on a commercial basis while capturing 97% of its CO 2 emissions:
0.06 Mt/y. CO 2 is compressed up to 3 bar and delivered by pipeline to a soda ash plant,
which is located 500 m away. Most of the plant has been built in carbon steel, and con-
struction has been privately financed without any government subsidies or grants. The
patented non-corrosive solvent and process configuration increase the efficiency of car-
bon capture and reduce the amount of energy required, the solvent loss and its degra-
dation, and thus the overall operating costs (40% reduction compared with conventional
technology). Owing to the non-corrosive nature of the solvent and the smaller size of
the equipment, it is claimed that the capital expenditure can be brought down by
30% compared with conventional technology. The technology has been demonstrated
at 31 facilities worldwide (Patkar and Bumb, 2017).