Sensitivity Analysis of Water Scrubbing Process for Biogas Purification
Sensitivity Analysis of Water Scrubbing Process for
Biogas Purification
Agung Sugiharto#, Sarto*, Sutijan*, Muslikhin Hidayat*
#
Chemical Engineering, Muhammadiyah University of Surakarta.
Jl. A Yani No 1, Surakarta
1
*
agung.sugiharto@ums.ac.id
Chemical Engineering, Gadjah Mada University.
Jl. Grafika No 2, Yogyakarta
Abstract— For vehicle fuelapplication,biogas need to have high
energy content. So, the gas has to be upgraded. The value of
energy in the biogas is in direct proportion to the methane
concentration. Raw biogas produced by anaerobic digester has
methane content about 50-60% and carbon dioxide as main
contaminant at 40-50% of volume. The methane content in
biogas can be upgraded by carbon dioxide removal process. In
contrary, carbon dioxide removal process need cost addition of
biogas production. It is important to have an optimized biogas
upgrading process in term of low energy consumption and high
efficiency giving high methane content in biogas. On the other
hand, it is very important to minimize emission of methane from
upgrading process because methane have a greenhouse gas effect
23 times greater than carbon dioxide.Water scrubbing is simplest
and cheapest technology to produce bio methane using biogas
upgrading process.The best control process scenario need to keep
the process work in optimal condition. But fluctuation of flow
and concentration in biogas produced by anaerobic digester
make difficultupgrading process control. By sensitivity analysis
study, control scenario for this process can decided in the best
way.
Keyword— biogas, carbon dioxide removal, sensitivity analysis,
upgrading biogas, water scrubbing.
I. INTRODUCTION
Energy have been essentially need for human live.
Electricity, fossil fuel, and natural gas are currently used as
main energy source inmodern human live.During the time, as
greater amount of human, as greater their energy need. For
along time ago until now,human mostly use fossil fuel as
energy source for live. This energy source not only is
unrenewable but also it amount is going down by the time.
Therefore, getting alternative energy resource that renewable
is most important.
The research of biogas production through anaerobic
digester process from many different feed sources have been
done. For example, fruit and beverage waste amount of 3-4
tons/day in Pasar Induk Buah dan Sayuran, Gamping, Sleman,
Yogyakarta consist of 12% volatile solid and 86% moisture
can produce 300 Nm3/day of biogas [1],[11].This gas product
usually do in direct application for domestic used and
occasionally for vehicle fuel producing electricity.
ICETEA 2015
Application of raw biogas without upgrading process to
vehicle fuel have several disadvantages as mention below:
1. Biogas has only 50-60% of volume of methane so it is not
efficient for direct combustion as fuel.
2. Several contaminant such as H2O and H2S make metal
corrosion of equipment.
3. It is less economics. Every cubic meter of biogas that
contained65% of methane have caloric value at 6.5 kWh,
otherwise for biogas that contained 97% of methane have
9.7 kWh of caloric value [8]. It can be compared to caloric
value at 9.8 kWh and 9.1 kWh of diesel oil and petroleum,
respectively.
Therefore upgrading biogas for vehicle fuel application is
urgently need to equipment corrosion preventing and to reach
high caloric value.
II. UTILIZATIONAND PURIFICATION OF BIOGAS
Biogas that can be used as vehicle fuel need to be cleaned
and upgraded its energy level.The basic principle of these
processes can be seen in Fig 1. Specific goal of these
processes are reaching pure biogas containing methane at least
95% of volume and carbon dioxide as main contaminant.
Several countries in Europe make standard quality of biogas
as vehicle fuel that can be seen in table 1.
Fig. 1 Basic flow sheet of biogas upgrading process.
-- Page 35 of 115 --
ISSN 2470-4330
TABLE1
BIOGAS STANDARD FOR VEHICLE FUEL[8]
not only absorption process that occurred but also chemical
reaction worked. Carbon dioxide is reacting to Amine ion but
methane is not reacting. Selectivity of this reaction is high, so
in finally biogas mostly pure contain of methane.For detail
comparison of several biogas upgrading process can be seen
in Table 2.
TABLE 2
COMPARISON OF BIOGAS UPGRADING TECHNOLOGIES[8]
PSA1
WS2
CS3
Pre-cleaning
Yes
Not
Yes
Pressure (bar)
4-7
4-7
1
Methane loss
< 3%, 6-10%
< 1%, < 2%
< 0,1%
>96%
>97%
>99%
Electricity
(kWh/Nm3)
0,25
Biogas Purification
Agung Sugiharto#, Sarto*, Sutijan*, Muslikhin Hidayat*
#
Chemical Engineering, Muhammadiyah University of Surakarta.
Jl. A Yani No 1, Surakarta
1
*
agung.sugiharto@ums.ac.id
Chemical Engineering, Gadjah Mada University.
Jl. Grafika No 2, Yogyakarta
Abstract— For vehicle fuelapplication,biogas need to have high
energy content. So, the gas has to be upgraded. The value of
energy in the biogas is in direct proportion to the methane
concentration. Raw biogas produced by anaerobic digester has
methane content about 50-60% and carbon dioxide as main
contaminant at 40-50% of volume. The methane content in
biogas can be upgraded by carbon dioxide removal process. In
contrary, carbon dioxide removal process need cost addition of
biogas production. It is important to have an optimized biogas
upgrading process in term of low energy consumption and high
efficiency giving high methane content in biogas. On the other
hand, it is very important to minimize emission of methane from
upgrading process because methane have a greenhouse gas effect
23 times greater than carbon dioxide.Water scrubbing is simplest
and cheapest technology to produce bio methane using biogas
upgrading process.The best control process scenario need to keep
the process work in optimal condition. But fluctuation of flow
and concentration in biogas produced by anaerobic digester
make difficultupgrading process control. By sensitivity analysis
study, control scenario for this process can decided in the best
way.
Keyword— biogas, carbon dioxide removal, sensitivity analysis,
upgrading biogas, water scrubbing.
I. INTRODUCTION
Energy have been essentially need for human live.
Electricity, fossil fuel, and natural gas are currently used as
main energy source inmodern human live.During the time, as
greater amount of human, as greater their energy need. For
along time ago until now,human mostly use fossil fuel as
energy source for live. This energy source not only is
unrenewable but also it amount is going down by the time.
Therefore, getting alternative energy resource that renewable
is most important.
The research of biogas production through anaerobic
digester process from many different feed sources have been
done. For example, fruit and beverage waste amount of 3-4
tons/day in Pasar Induk Buah dan Sayuran, Gamping, Sleman,
Yogyakarta consist of 12% volatile solid and 86% moisture
can produce 300 Nm3/day of biogas [1],[11].This gas product
usually do in direct application for domestic used and
occasionally for vehicle fuel producing electricity.
ICETEA 2015
Application of raw biogas without upgrading process to
vehicle fuel have several disadvantages as mention below:
1. Biogas has only 50-60% of volume of methane so it is not
efficient for direct combustion as fuel.
2. Several contaminant such as H2O and H2S make metal
corrosion of equipment.
3. It is less economics. Every cubic meter of biogas that
contained65% of methane have caloric value at 6.5 kWh,
otherwise for biogas that contained 97% of methane have
9.7 kWh of caloric value [8]. It can be compared to caloric
value at 9.8 kWh and 9.1 kWh of diesel oil and petroleum,
respectively.
Therefore upgrading biogas for vehicle fuel application is
urgently need to equipment corrosion preventing and to reach
high caloric value.
II. UTILIZATIONAND PURIFICATION OF BIOGAS
Biogas that can be used as vehicle fuel need to be cleaned
and upgraded its energy level.The basic principle of these
processes can be seen in Fig 1. Specific goal of these
processes are reaching pure biogas containing methane at least
95% of volume and carbon dioxide as main contaminant.
Several countries in Europe make standard quality of biogas
as vehicle fuel that can be seen in table 1.
Fig. 1 Basic flow sheet of biogas upgrading process.
-- Page 35 of 115 --
ISSN 2470-4330
TABLE1
BIOGAS STANDARD FOR VEHICLE FUEL[8]
not only absorption process that occurred but also chemical
reaction worked. Carbon dioxide is reacting to Amine ion but
methane is not reacting. Selectivity of this reaction is high, so
in finally biogas mostly pure contain of methane.For detail
comparison of several biogas upgrading process can be seen
in Table 2.
TABLE 2
COMPARISON OF BIOGAS UPGRADING TECHNOLOGIES[8]
PSA1
WS2
CS3
Pre-cleaning
Yes
Not
Yes
Pressure (bar)
4-7
4-7
1
Methane loss
< 3%, 6-10%
< 1%, < 2%
< 0,1%
>96%
>97%
>99%
Electricity
(kWh/Nm3)
0,25