pwr_october-2024 - 32

FOSSIL TOP PLANT
Attarat Power Plant
Unlocks Domestic Energy
Source for Jordan
Courtesy: Attarat Power Company
Oil shale doesn't fuel a lot of power plants around the world, but in Jordan, it's a
vital option, offering energy security and independence. The success of the Attarat
Power Plant in capitalizing on this valuable indigenous resource led to its selection
as a POWER Top Plant award winner.
Aaron Larson
Historically, very little has been done
J
ordan is a country whose fuel and
electricity industries are mostly dependent
on imported crude oil and
natural gas. Its only important indigenous
source of energy is oil shale. Yet, oil shale
is abundant in Jordan. According to a report
published by the country's Ministry
of Energy and Mineral Resources, Jordan
possesses more than 65 billion tons
of geological oil shale reserves, ranking
it eighth in the world, ahead of countries
such as China, which is more than 100
times its size.
A Unique and Challenging
Resource
Oil shale is a sedimentary rock rich in organic
matter known as kerogen, which
when heated, breaks down and releases
hydrocarbon. Oil shale can be thought of
as a precursor to oil and natural gas; with
more pressure and over longer geological
time, the kerogen would heat to its
oil and gas window to release crude oil
or natural gas.
Oil shale is extracted using conventional
mining techniques. It is crushed
and burned as fuel to produce electricity
or heated up using a retorting system
to produce synthetic shale oil. The liquid
shale oil is a synthetic crude oil that can
be treated and refined into other petroleum
products, such as diesel, gasoline,
and jet fuels.
32
to exploit Jordan's oil shale reserves,
but that has changed in recent years.
One project that has tapped into the resource
is the Attarat Power Plant. It was
constructed about 110 kilometers southeast
of Amman, Jordan's capital and the
largest city in the country. Attarat's two
235-MW units, which entered commercial
operation in October 2022 and May
2023, respectively, were brought online
to burn oil shale and produce electricity.
The two units are now capable of supplying
about 15% of Jordan's annual
electricity demand.
Mining and burning oil shale are challenging
compared to other solid fuels. Jason
Pok, CEO of Attarat Power Company,
explained that the average thickness of
the overburden over the resource block
is about 60 meters (m). Meanwhile, the
average mineable oil shale layer thickness
is only about 30 m.
Oil shale also has a low calorific value
compared to other fuels. Specifically,
Jordan's oil shale has an average lower
heating value (LHV) of 3.8 Megajoules/
kilogram (MJ/kg, 1,660 Btu/lb). Its moisture
content is 15% to 22%, and the ash
content is not less than 60%. Meanwhile,
there is also significant variation in
the LHV and other chemical composition
at the mine, which must be managed.
Fly ash generation can be a problem and
crushing issues are also prominent.
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Overcoming Problems
To manage these challenges, Attarat
uses a variety of methods. At the mine,
a plan was developed to manage and
expand the open mouth mine (Figure 1).
Remarkably, more than 40 pieces of mining
equipment are used around the clock
in the process. Jason Pok said a revised
blending schedule and different mixing
methods have increased the fuel's LHV
to as high as 4.1 MJ/kg (1,763 Btu/lb).
Attarat's Sumitomo SHI FW circulating
fluidized bed (CFB) boilers are designed
to deal with the high ash levels
found in oil shale. By recirculating the oil
shale through a cyclone, CFB technology
achieves a high combustion efficiency.
Sumitomo SHI FW says CFB boilers
are designed to withstand the harshest
conditions and can better resist tube corrosion,
wear, and ash adhesion, making
high-temperature, high-pressure steam
conditions possible for all fuels. The Attarat
boilers operate at a main steam
pressure of 166 bar (about 2,400 psi) and
main steam and reheat steam temperature
of 539C (about 1,000F).
To deal with the high ash content in
the fuel, the boilers are installed with 60
high-energy sootblowers, spring hammers,
and acoustic cleaners to enhance
the boiler ash cleaning. The plant has an
automatic ash handling system. Concerning
the usage of high amounts of
oil shale with high ash content and the
POWER | October 2024
http://www.powermag.com
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