pwr_july-2024 - 20

WATER AWARD
Epasa Breakthrough Transforms
Heavy Fuel Oil Sludge into
Resource Stream
Sonal Patel
F
or nearly a decade after Centrais
Elétricas de Paraíba-or Epasa-
began commercial operation of its
Termonordeste and Termoparaíba plants
in 2010, the Brazilian independent
power producer grappled with the dual
responsibilities of providing thermal
power for reliability while addressing
its shareholders' environmental concerns.
The two power plants near João
Pessoa, a dynamic coastal city on Brazil's
eastern tip, contribute a combined
capacity of 342 MW, making them together
the second-largest fuel oil thermoelectric
complex in Brazil and among
the top five largest in the world. As Epasa
Plant Manager Marcelo Agra Junior
explained to POWER, the facilities are
each equipped with 20 engines from
MAN Energy Solutions, including 19
MAN/STX 18V32/40 engines with a generating
capacity of 8.76 MW each and
one MAN/STX 9L32/40 engine capable
of 4.38 MW. Epasa utilizes OCB1, a lowsulfur
content heavy fuel oil (HFO), to
fuel its operations.
While Brazil now relies on renewables-mainly
hydropower-for 80% of
its generation capacity, the plants play a
pivotal role as a standby resource when
reservoir levels at Brazil's hydropower
facilities are low, Agra said. However,
the thermoelectric's environmental
posture has come under sharp relief
in recent years, owing partly to a soci20
etal
embrace of decarbonization and
a sustainability push by Epasa's two
shareholders-CPFL Energia, Brazil's
second-largest transmission and distribution
company, and EBRAZIL, a thermoelectric
power giant in Brazil. " So,
we focus a lot on mitigating our environmental
impact as much as possible,
[mainly] by mitigating our productive
process and our impacts on the local
community, " he said.
For years, Epasa's most significant environmental
impacts came from ensuring
its HFO was adequately purified, a
step essential to protect and extend the
life of its engines. Impurities in HFO can
lead to significant wear and tear, operational
inefficiencies, and even failures.
To purify its raw HFO, Epasa had used
centrifugal separators manufactured by
German firm GEA and Swedish company
Alfa Laval. Centrifugal separators purify
HFO by rapidly rotating the oil to generate
centrifugal force, separating the
denser impurities and water from the oil,
efficiently clarifying the oil for use in engines
and generators.
Centrifugal separators, however, produce
sludge, a concentrated mass that is
often composed of separated impurities
and water, which gets entrapped with
the solid particles during the separation
process. At Epasa, which uses 1,600
tonnes of HFO daily when it is generating
at total capacity, sludge beneficiation
had quickly grown into an imperative.
www.powermag.com
Courtesy: Centrais Elétricas de Paraíba
Brazilian independent power generator Epasa faced significant environmental and
operational challenges with heavy fuel oil sludge. Through innovative engineering
and problem-solving, the company developed a state-of-the-art two-stage de-watering
and de-oiling process that transforms sludge into reusable resources.
" Normally, our sludge composition is
80% of water and 20% of oil, " Agra explained.
Before, Epasa would truck out
the sludge to a third party for treatment,
with the recovered oil going to industry,
he said.
" So, imagine the quantity of trucks
that we needed to send this sludge-
which is mainly water-to a third party
to treat. " Agra noted that the practice
was both expensive and environmentally
averse.
1. Epasa's system featured a GEA OSE 80
for sludge beneficiation and the WSE 20 bilge
separator for purifying oily water before disposal.
Courtesy: Epasa
POWER | July 2024
http://www.powermag.com
pwr_july-2024

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