Page 80 - New Trends In Coal Conversion

46 New Trends in Coal Conversion

stripper at higher temperature and lower pressure by means of low-pressure steam. In
the sour operation mode, H 2 S was cocaptured with CO 2 . The capture unit produced
concentrated CO 2 (with 1%e3% H 2 S in sour mode) and a product with 77.4% H 2
that was purified in a PSA unit. This project demonstrated the feasibility of PRECC:
the pilot plant operated for over 550 h, capturing 1,000 t of CO 2 and producing 6 t of
high purity H 2 (99.99%). The results of the pilot were used to estimate the cost of a
capture unit for the full IGCC plant: 26 V/t for a capture rate of 90% without consid-
ering compression (Casero et al., 2014). Unfortunately, ELCOGAS shut down in
2016.
EAGLE project captured CO 2 from a slipstream of 22 t/d of syngas from an
oxygen-blown IGCC coal system. The 150 t/d gasifier, located at J POWER’s
WakamatsuResearchInstitute, used a single chamber with two-stage swirling
flow to achieve high-efficiency gasification. The oxygen feed was varied according
to coal type to ensure reliable syngas characteristics. Purification of the syngas was
achieved through a cold gas cleanup process before the separation and capture of
CO 2 . Chemical and physical absorption were evaluated for PRECC: physical ab-
sorption indicated a 10% energy saving relative to the chemical alternative tested.
The Osaki CoolGen Project is using the knowledge and expertise gained in EAGLE
to demonstrate oxygen-blown IGCC technologies at large scale including physical
absorption CO 2 capture technology. A 166 MW IGCC plant was built in Osakika-
mijima, Japan, with the same gasification technology used in the EAGLE project.
Air separation is performed by cryogenic distillation, and syngas purification is per-
formed in the sulfur removal and recovery facilities. Capture demonstration will
start in 2019, and the scope for efficiency improvements by combining fuel cells
with the oxygen-blown IGCC system, including CO 2 capture, will be evaluated
by 2021.
The RTI warm gas desulfurization process (WDP) uses a pressurized dual
transport-bed reactor design and a proprietary solid sorbent that is capable of removing
up to 99.9% of the total sulfur contaminants directly from raw syngas at gasifier pres-

sure and warm process temperature (250e650 C). This technology has been validated
at precommercial scale (50 MW e ) by treating a slipstream of approximately 20% of the
3
coal-based raw syngas of Tampa Electric Company’s Polk 1 IGCC (60,000 Nm /h), in
Florida, United States. The project involves combined gas cleanup making use of
WDP with PRECC using the aMDEA® process. The plant completed over 3,500 h
of WDP testing on coal-based syngas, over 2,000 h of WDP combined with
aMDEA®, and approximately 700 h of integrated WDP, WGS, and aMDEA®.
WDP technology has demonstrated to achieve up to 99.9% removal of total sulfur

from syngas at temperatures as high as 650 C, over a wide range of sulfur concentra-
tions and pressures. The integration of WDP with a downstream aMDEA® unit
allowed for further reduction of total sulfur up to 99.999%. Slipstream testing of the
final cleaned syngas using FischereTropsch and methanol catalysts showed no signif-
icant catalyst deactivation from residual contaminants after several hundred hours of
exposure. A technoeconomic analysis carried out by RTI for a 600 MW e IGCC plant
with PRECC pointed out that the decoupling of SO 2 and CO 2 removal reduces both
CAPEX (by 33%) and OPEX (by 45%) compared with a dual-stage Selexol process.