1. The document describes conditions related to backflow from a flare to a biodigester under three scenarios: morning time, day time before backflow, and day time when backflow occurs. 2. In the morning, temperatures are low and biogas flows to the flare with valves and pipes configured to allow flow. 3. During the day before backflow, temperatures rise and biogas production increases, inflating the membrane. 4. When backflow occurs, the membrane lifts suddenly, opening the gas relief pipe and creating suction that pulls flame, air, and biogas back into the digester through the pipe.

1. 1
Backflow from Flare to Biodigester

2. 2
Condition # 1 : Morning Time
HDPE
baffle
sludge layer
mixer
Biogas flow to flare
T1
T3
T2
Morning time, T1 = T2, T3 depend on
Temp from POME
1. Flare ON
2. Dampener OPEN
3. Biogas valve OPEN
4. Gas relief pipe CLOSE ( lock by
water )

3. 3
Condition # 2 : Day Time before backflow
HDPE
baffle
sludge layer
mixer
Biogas flow to flare
T1
T3
T2
Day time, T2 = 60 deg C, T1 = 35
deg C, T3 depend on Temp from
POME
1. Flare ON
2. Dampener OPEN
3. Biogas valve OPEN
4. Gas relief pipe CLOSE ( lock by
water )
5. Membrane will start inflate due
to biogas production is higher
during mill operation and
expansion from temperature
increament

4. 4
Condition # 3 : Day Time when Backflow happen
HDPE
baffle
sludge layer
mixer
Biogas + air + flame
suck to digester
T1
T3
T2
Day time, T2 = 60 deg C, T1 = 35
deg C, T3 depend on Temp from
POME
1. Flare ON
2. Dampener OPEN
3. Biogas valve OPEN
4. Gas relief pipeOPEN ( when
membrane lift up suddently )
5. Membrane will lift up some of
gas relief pipe. Most of biogas
will release from this pipe and
make a vacuum effect to flame
and air on flare area. This is
when the flowback (back
pressure) started.
The flow to biodigester
is stuck in demister
because of fill media
and an equilibrium
between the pressure
and then BOOM