POWER July 2010 - 42

AIR QUALITY MANAGEMENT
ReACT Reduces Emissions
and Water Use
Regenerative activated coke technology (ReACT) is an integrated multipollutant
control approach that removes SOx, NOx, and Hg from coal-fired plants by
adsorption with activated coke to attain emissions levels found at natural
gas-fired plants. One big advantage of this technology is that it uses only
a fraction of the water used by conventional wet flue gas desulfurization.
A recent license agreement brings this technology to the U.S.
By H. James Peters, Hamon Research-Cottrell Inc.
R
outine reductions in air emissions
limits are a fact of life for power
generators around the globe. In the
U.S., adding wet flue gas desulfurization
(wFGD) to remove SO2
lytic reduction (SCR) for NOx
and selective catacontrol
are
de rigueur for new plants, and these systems
also have been retrofitted onto hundreds
of operating coal-fired plants. The
future will likely bring increasingly stringent
control of criteria pollutants such as
mercury and other hazardous air pollutants,
plume visibility, disposal issues, as well as
new greenhouse gas emission controls.
The conventional approach to controlis
by using either wFGD or a dry
1. Best-in-class performance. The Isogo repowering project replaced two 265-MW
conventional pulverized coal boilers and pollution control equipment (ESP and wFGD) with two
600-MW ultrasupercritical boilers fitted with ReACT advanced multipollutant controls. The newly
repowered plant claims the title as the world's lowest emissions-intensity coal-fired power
plant. Design of the plant, located in Yokohama harbor, also considered plant aesthetics, including
visibility of the stack. Courtesy: J-POWER
ling SO2
spray dryer absorber (SDA). Another option
is regenerative activated coke technology
(ReACT), an integrated multipollutant
control approach that not only can remove
SO2
and NOx
from the flue gas stream but
also removes mercury (Hg) through adsorption
using activated coke. The activated
coke sorbent is regenerated in the process
while using only 1% of the water required
by conventional wFGD systems. ReACT is
fully commercial on coal-fired projects up
to 600 MW in Japan and is now available in
the U.S. through a recent license agreement
between J-POWER Entech and Hamon Research-Cottrell
Inc.
World-Class Performance
Japan's Electric Power Development Corp.
(EPDC) first negotiated pollution control
permits for its 2 x 265-MW Isogo Thermal
Power Station (Isogo) with the city of Yokohama
City in 1964. EPDC launched a number
of initiatives in the following years, including
installing the first wFGD system in Japan.
After operating Isogo for more than 30
years, EPDC (now J-POWER) committed
to replace the plant and negotiated with the
city of Yokohama for a major repowering
project, which would more than double gen42
eration
capacity at the site yet further reduce
emissions with more stringent environmental
controls. The J-POWER/Isogo repowering
project replaced the two vintage coal-fired
units while more than doubling the generation
to two 600-MW units within the same
site limits. J-POWER's newly repowered
Isogo burns low-sulfur coal and incorporates
high-efficiency ultrasupercritical boilers,
low-NOx
burners and controls, primary
SCR, electrostatic precipitators (ESPs), and
ReACT (Figure 1).
After more than eight years of operating
experience at Isogo Unit 1 (the plant entered
service in 2002), the ReACT system performance
has been exceptional:
www.powermag.com
Based on this record of Unit 1 performance,
J-POWER agreed to a more stringent
permit level for the second unit. Unit 2 began
commercial operation in mid-2009.
Today, Isogo ranks as the cleanest coalfired
power plant in the world in terms of
POWER | July 2010
■ Less than 5 ppm of SO2
at the stack with an
SO2 inlet concentration of 200 ppm-400
ppm. SOx removal efficiency is over 98%.
■ Greater than 90% mercury removal.
■ An additional 20%-40% NOx
reduction
provided by ReACT as a co-benefit, dropping
stack NOx
ppm. An SCR is installed upstream as the
primary NOx
control.
concentrations to <10

http://www.powermag.com

POWER July 2010

Table of Contents for the Digital Edition of POWER July 2010