A.C.R. Panopio, R.P. Solis,

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COLD RI TESTING Formula 3680 Bacon-Manito
Geothermal Production Field

• A.C.R. Panopio, R.P. Solis,
• Eastern Technologies Inc.

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• Philippines is the 2nd largest producer of
  geothermal energy in the world
• Installed capacity todate is 1,935 MWe
• Energy Development Corporation (EDC) operating
  five of seven geothermal fields in Philippines

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Bacon-Manito Geothermal Field
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Botong Brine Characteristics

• high silica content (1,000 mg/kg TSiO2)
• SSI 1.45 or 45 oversaturation with amorphous
  silica in the brine separated at 0.70 MPaa
  (165C)
• 300 mg/kg excess silica
• Brineflow 20 kg/s

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Objectives of the Testing

• To determine the efficiency and inhibition
  property of Formula 3680 (F3680)
• To determine the effective dosing concentration
• To characterize the type of deposits formed

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Description (as per MSDS)

• Formula 3680 - Polyacrylic acid copolymer

Typical Properties Appearance clear brown
liquid Odor slight to no odor Specific
gravity 1.25 0.02 pH 5.5 0.5 Thermal
Stability 285C
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Botong RI System
Separator Vessel
Silencer
Dosing Point
Thermal Pond
Open Canal
RI Well
Power Plant
Production Wells
HOT SECTION
COLD SECTION
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Botong Hot RI System
BOTONG SEPARATOR BRINE LINE
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Botong Cold RI System
SILENCER - MINI THERMAL POND - DEARATOR POND
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Schematic Diagram
Chemical Dosing
Mini-silencer
Mini-separator
2-phaseline header
Brineline
0.68 MPa or 163C
SP-3
SP-2
Open pipe
Steamline
Thermal Pond
SP-4
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Testing Schemes

• Concentration of F3680 tested were 5, 10, 20
  mg/kg
• Dosing rate is lt1 of the total brine flow
• TSiO2 along the line were monitored

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Actual Set-up
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Actual Set-up
SP-2
SP-3
Lane 1
Lane 2
Lane 3
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Lower brine temperature approaches the
pseudo-equilibrium solubility curve which prevent
spontaneous crystallization

• The pseudo-equilibrium solubility curve
  delineates the point at which spontaneous
  crystallization can occur
• Weakly flocculated and non-adhesive deposits are
  formed

Source Fleming B. A., 1986. Journal of Colloid
Interface Science
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The drop in TSiO2 at the end of the test set-up
is the amount of silica that deposited along the
line (gt200ppm)
10 ppm
20 ppm
5 ppm
blank
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Treating the brine with F3680 reduces the
deposition rate at least about 40
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• Deposition rates of F3680-treated brine is
  lesser than blank run
• The linear relation between deposition rate
  and the monomer of blank run is due to absence
  of inhibitor
• Treating the brine with 10 ppm F3680 showed
  the least deposition rate

B
l
a
n
k
2
0

p
p
m
5

p
p
m
1
0

p
p
m
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Lane 1 (70-90C)
)
y
a
d
/
m
m
6
(

e
t
a
R

n
Lane 2 (56-66C)
o
i
t
i
4
s
o
p
Lane 3 (40-55C)
e
D
2
0
90
80
70
60


m
o
n
o
m
e
r
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5 ppm F3680
Layered, thin and flaky
Porous but grainy
Flaky, brittle, and loose

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10 ppm F3680
layers of thin but moderately hard, flaky when
dried
granular and compact, powdery when dried
soft and porous, powdery when dried
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20 ppm F3680
Lane 1
Lane 2
Lane 3
Layered, grainy, moderately hard
Thin, flaky and loose
Soft and porous
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10ppm F3680-treated brine achieved the highest
inhibition efficiency of 55.8.
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Summary of Findings

• F3680 reduces deposition rate of silica by 40
• 10ppm treated brine achieved the highest
  inhibition efficiency of 55.8
• F3680 can be an alternative to the existing
  silica inhibitor as long as regular cleaning of
  the sumps and thermal ponds will be implemented

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Summary of Findings
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