WASTE GASES AND PARTICULATES RESULTED FROM BRIQUETTE
COMBUSTION
Dr. Ukar W. Soelistijo**)
Email: [email protected];[email protected]
Dr. Retno Damayanti, MCTRDC*)
[email protected]
ABSTRACT
One of many coal utilization as fuel is usage of coal briquette that is expected to be able to meet household and
small industry demand for fuel. The negative impact caused by utilizing briquette is air pollution due to the emission
of gas removal resulted from its burning in the forms of fly ashes as small particles and toxic gases. Research on
gases removal from burning of coal briquette has been carried out, in particular gases of COx, NOx, and SOx. The
samples used are of Palimanan West Java (MCTRDC Pilot Plant Coal Center Laboratory) waste wood briquette
(BS), waste agriculture briquette (BB), and Tanjung Enim coal briquette (BT) and Lampung coal briquette (BL),
where charcoal (AK) is used as a standard of comparison. The research results show that the disposal gas emission
of the five types of fuel have similar pattern, i.e. within the first twenty minutes at the temperature of 150-600 0C the
gas emission are still below the EQS (300 mg/m3). The effort of controlling of air pollution could be carried out
towards preserving the environmental quality through, among others, planting several types of plants that could be
able to absorb the polluter gases, and the efforts of REDD that should be necessarily encouraged as far as possible.
Keywords: biomass and coal briquettes, combustion, pollutant emissions, mitigation.
*) Senior Researcher of MCTRDC. MCTRDC is the Mineral and Coal Technology Research and Development
Center, Ministry of Energy and Mineral Resources, Republic of Indonesia.
**) Bandung Islamic University, Indonesia; The retired Senior Researcher of MCTRDC.
This paper is submitted to Air Quality VIII, An International Conference on Carbon Management, Mercury, Trace
Substances, SOx, NOx, and Particulate Matter, October 24-27, 2011, Arlington, VA, USA.
I.INTRODUCTION
I.1 Background
Since the energy crisis happened in 1970s and the ever declining of Indonesia oil reserves, then the
government has launched the national energy policy !). The national energy policy contains three important issues,
i.e.:
- Intensification is aimed to increase the activity of survey and exploration in te framework of recognizing more
viable potential of energy resources.
- Diversification with the aim of reducing domestic oil utilization and increasing diversification of energy
alternative utilization other than oil.
- Conservation is aimed to utilize more efficient of conserving energy resources.
The present Indonesia coal reserves are of about 21 billion tonnes out of 101 billion tonnes of coal
resources spread over Indonesia islands, mainly in Sumatera, Kalimantan and view in Sulawesi, Java, and Papua
(Ministry of Energy and Mineral Resources, 2009). The main consumers of coal are power plant and cement
industry. Small amount of coal is used in tin smelting, ferronickel, view of small industry such as brick and tile,
lime, earthenware, blacksmith etc. The limited reserves of oil and gas, then the other fossil fuels such as coal would
be developed as fuel in the industry including small industry, besides also developing the available alternative
energy sources such as geothermal. One of several coal utilizations as fuel is of coal briquette to meet the demand of
households and small industry. Even though, utilization of coal briquette has defect of releasing pollution due to gas
emission resulted from burning briquette in the forms of particulate (dust) and toxic gases such as sulfur dioxide
(SO2), nitrogen oxide (NOx), carbon oxide (COx) and other organic compounds. 4) If the concentration of gases and
particulates exceeds the limit threshold, it could disturb the worker’s health and the surroundings. While the
excessive of gases such as SO2 and NOx could cause the acid rain, and CO2 could affect green house effects and
destroying ozone layer in the atmosphere and finally decreasing the quality of the surrounding environment and
disturbing the human’s life. 5)
Recognizing the level of polluting influence of several types of briquettes on the environment, this
investigation is carried out by using rice husk and wood waste briquette, sugar cane waste briquette, charcoal
compared with coal briquette which are used to feed in the small industry. The observed pollutant gases are SO2,
NOx, COx, NH3, HC, and dust (ashes) based on the Decree of the Indonesia Minister of Environment on the Limit
Threshold Value and on the Environment Quality Standard.
I.2. Problems
Utilization of briquette fuel affects quality of ambient atmosphere in lieu with its usage in the small
industry. Gases emission resulting from briquette combustion would be studied in this investigation mainly of green
house gases such as COx, SO2 and NOx and other hydro carbon gases in line with its safety of emission. The
samples would be taken from Tanjung Enim and Lampung coal briquette (The Bukit Asam State-owned Coal
Enterprise), charcoal, rice husk-wood waste briquette and sugar cane waste briquette.
I.3 Purpose and aim
The aim of investigation is to recognize the level of emission effect of briquette combustion in the small
industry sector on air, then the figure out of the pollution impact on air could be obtained. Moreover, since after
recognizing the level of emission then the effort of controlling of air pollution due to the briquette combustion could
be conducted so that preservation of the environmental quality is maintained.
Furthermore, basic data of the disposal gas emission from briquette burning could be supplied an input for the
small industry to manage its gas emission. Besides, this data could be utilized by the community in their
participation in environmental management and control.
II. THEORY
II.1 Combustion process
Mechanism of combustion process is so complex as long as the briquette fuel has complex chemical composition
and physical characteristics and it is burned under uncontrolled condition in the small industry. Combustion process
occurs while briquette reacts with oxygen in air and resulting heat and disposal gases and particulates. Heat is
utilized by the various industrial processes.
In the combustion process of briquette, the fuel is never directly burned and in a very short time the combustion
process occurs within three stage of reaction, i.e. 3):
a). Introductory combustion.
In this stage of reaction, cellulose compound and hemi cellulose of the fuel breaks and forming activated
cellulose compound, i.e. the compound that has smaller molecule weight.
b). Pyrolysis reaction.
In this reaction occurs degradation of heat of the activated cellulose to be volatile compound and charcoal.
The formation of this compound depends on reaction temperature. The volatile compound product could constitutes
as gases (CO2, CO, H-C,SO2 and H2), the condensed fraction (H2O and organic compound), and tar fraction.
c). Reaction of combustion
At this stage, results of pyrolysis reaction, i.e. the volatile compound and charcoal, under enough oxygen
and high temperature, is completely burned and forming CO2 and heat (exothermic). This condition is indicated by
the blue color of flame. Under the condition of lack of oxygen and low temperature, then it is indicated by the
existence of smoke or emission as the product of pyrolysis reaction.
In general, based on the phase of formation, the pollutant of the briquette combustion could be divided into
two parts, i.e.,
a). Primary pollutant, is the pollutant in the air that has the same form or phase with when it is emitted from
its source. For example, SO2 is emitted from the metal refining plant; or COx, NOx, SO2 originated from fossil
fuels.
b). Secondary pollutant. This pollutant exists in the air as the result between two or more materials or pollutant.
The possible reaction is:
- Photochemical reaction: ozone as the result of reaction between hydrocarbon with NOx under the influence
of ultra violet from the sunlight.
- Catalytic oxidation: formation of gaseous oxides with metallic particulates in the air as catalyst.
Based on its form, the kinds of air pollutant could be divided into: particulates (dust, fume and smoke) and
gases (CO, SO2, NOx, and hydrocarbon).
Ash as solid waste of briquette combustion activity is generally disposed as usual. Its reutilization as one way of
environmental management is usually as soil fertilizer of plants of small industry. Considering that ash as result of
any combustion is categorized as dangerous and poisonous material, so that in this investigation toxicity of the
resulted ash is also conducted. The consideration is that there is an uneasiness of contamination occurrence on the
water body at the surrounding of the small industry area that uses briquette.
II.2 Impact of pollutant of briquette combustion
Air pollution caused by briquette combustion depends on the types of pollutant, concentration of pollutant, the
length of time the pollutant existing in air and endurance capacity of the living creature upon the pollutant 13).
In general, the pollutant of air could lead direct impact, viz. upon worker besmirched by pollutant material
directly. The indirect impact is upon the community who lives at the surrounding of the industry that releases the air
pollutant per se. Several important characteristics of gas pollutant and its impact can be seen on Table 2.1.
Table 2.1
Gas as pollutant material
No.
GAS
Important characteristic
Pollution
1.
Sulfur dioxide (SO2)
- colorless
- des - - destroying plant
- not strong odor
- health interference
- high solubility in water forming sulfide
acid
2.
Sulfur trioxide (SO3)
3.
Nitrous oxide (N2O)
- colorless
- as carrier in aerosol
- inert
4.
Nitrogen monoxide (NO)
- colorless
5.
Nitrogen dioxide (NO2)
- occured on high temperatue and
pressuire
- oxidized into NO2
- the main component in the formation
of photochemistry fume
6.
Carbon monoxide (CO)
- colorless
- odorless
7.
Carbon dioxide (CO2)
- colorless
- solving in water and forming sulfate acid
- brown color up to orange
- very corrosive
- as the result of incomplete combustion
process
- affects on the global climate
- odorless
8.
Hydrocarbon (CnHn)
- depending on its type
- some are resulted by industry
III. IMPLEMENTATION (SEQUENCE) OF INVESTIGATION
III.1 Location and raw material
Location of disposal gas emission investigation is at the small industry and at Palimanan Coal Pilot Plant
MCTRDC, West Java, supported by the Environmental Laboratory of MCTRDC in Bandung. Sample of briquette is
consisted of coal briquette from Tanjung Enim (BT) and Lampung (BL) PT Bukit Asam (State-owned Coal
Company in South Sumatera), biomass briquette (rice husk and wood waste briquette (BS)) and sugar cane waste
briquette (BB), and also charcoal (AK) as comparative testing.
III.2 Methodology
Methodology may include data collection and analysis, laboratory analysis, data evaluation and report writing.
3.2.1 Data collection and analysis
The collected data may include the primary data obtained by direct observation on environmental
parameter/component at the field and sample collection the further analyzed at the laboratory. Secondary data is
collected from the coal briquette production plants and from the consumers at the location of investigation.
3.2.2 Procedure of investigation
a). Raw material study
Characteristics of raw materials is determined through chemical analysis at the MCTRDC laboratory that may
include proximate analysis (moisture, ash, volatile matters, and fixed carbon) and ultimate analysis (C, H, N, O, S).
Coal ashes analysis is carried out to determine the component of major elements (alkali oxides and earth elements)
and other metallic elements (Pb, Cu, Zn).
b). Determination of heat energy and efficiency of furnace
Determination of furnace efficiency is carried by using water boiling method. 3,7,10,14) The equipments may
include pair of scales, thermometer, stopwatch, thermocouple, furnace, and aluminum pan. The equipment is then
set up and testing is conducted in line with the procedure, heating within 60 minutes . Then calculating maximum
heat power and efficiency of the heat power (CO2, SO2 and NOx) at the several horizontal points of farther location
from the furnace in the testing room.
c). Determination of disposal gas emission
In this testing is conducted by using stack above the furnace. Testing is set up at the bottom of the stack or 50
cm above the furnace and above the stack or 200 cm above the furnace. Then CO2, SO2 and NOx are determined
with length of time variation.
d). Determination of toxicity of ashes resulted by burning of briquette
Ashes resulted by burning of all samples of briquette and charcoal then its toxicity is tested by using EPA
method 1311, Toxicity Characteristics Leaching Procedure. 7,8).
This testing uses the weight of every sample of 5 grams of waste solid.
IV. RESULT OF INVESTIGATION AND DISCUSSION
IV.1 Characteristics of fuel
Chemical characteristics of fuels (briquettes and charcoal) used in this investigation is determined by proximate
analysis and ultimate analysis. The result is shown on Table 4.1.
It can be seen that the content of moisture is relatively low in the range of 5.46 -11.81%. The higher the content
of moisture the slower rate of combustion. Ash content of the samples used in this investigation ranges between
1.43-22.34%. The lowest content of ash is in charcoal of 1-2%, while in rice husk and wood waste briquette of
about 20-25%. Volatile matters constitutes component of fuel if it is burned it would become vapor. Volatile matters
content is of 24.74 –76.72%, while fixed carbon if of 11.69-52.23%.
Table 4.1
Result of proximate and ultimate analysis of fuel
No.
Parameter
Unit
Fuel
AK
BB
BS
BT
BL
1.
Moisture
%
10.16
7.25
5.46
5.81
11.81
2.
Ash
%
1.43
18.36
22.34
17.22
11.25
3.
Volatile matters
(V.M.)
%
76.72
45.22
43.76
24.74
37.69
4.
Fixed carbon
%
11.69
29.17
28.44
52.23
39.25
5.
Carbon
%
78.84
48.27
50.40
59.35
57.49
6.
Hydrogen
%
3.42
4.70
4.79
3.81
5.69
7.
Nitrogen
%
0.38
0.70
0.92
0.85
0.87
8.
S total
%
0.58
1.07
0.80
0.50
0.30
9.
Oxygen
%
15.35
26.90
20.75
18.27
24.40
10.
Calorific value
Cal
6970
4516
4905
5411
5565
Legend: AK: Charcoal; BB: Sugar cane waste briquette; BS: Rice husk and wood waste briquette; BT: Tanjung
Enim coal briquette (super); BL: Lampung coal briquette; Calculation base on air dry basis (a.d.b.).
The result of ultimate analysis may include the important elements such as C, H, O, N, and S. The elements of
C, H, and O constitutes determinant parameter in the process of combustion. The content of those elements is of
40.27-78.84%, 3.42-5.69% and 15.35-26.90% respectively. The elements of S and N are of 0.30-1.07% and of 0.380.92% respectively. C will form gas of CO2, H to be H2O, S becoming SO2 and N to be NOx. Calorific value of the
briquette samples is between 4.516 and 6.970 cal.
IV.2 Temperature of furnace and water
Temperature of furnace can be seen on Figure 4.1 and water on Figure 4.2 and shown as the average temperature during
the on-going experiment. The observed data shown that the average highest temperature of furnace with using BB
briquette reaches 550 0C, while using BL the average highest temperature only reaches 380 0C, and the other three
briquette fuels, i.e. BS, BT and AK, reach the average highest temperature reach around 250 0C. In accordance with
the average highest temperature of water in the furnace of using fuel BB increases faster than using other types of
fuels.
800
T
E
M
P
E
R
A
T
U
R
E
600
400
oC
200
0
0
5
BB
10
BS
AK
15
BL
20
25
BT
30
waktu (menit)
Tim e (m inute)
Figure 4.1
The average temperature of furnace using various of fuels
120
100
T
E
M
P
E
R
A
T
U
R
E
80
60
40
oC
20
0
0
10
20
30
40
AK
BB
BS
BT
50
BL
60
70
80
90
waktu
Time
(minute)(menit)
Figure 4.2
The average temperature of water during experiment using various of fuel
On Figure 4.2, it can also be seen that using the three types of fuels of BS, BT, and AK show the same increase
of water temperature.
IV.3 Heat energy and efficiency of furnace
Heat energy and efficiency of furnace, in this investigation, are determined under two conditions, i.e.,
maximum condition and minimum one. Maximum condition is where the in-take air into the furnace is maximum,
and minimum condition is vice versa. The energy received by water in the pan is used to increase temperature and
evaporation the water. Data of heat energy and efficiency of furnace obtained in this investigation can be seen in
Table 4.2 . Based on the result of experiment can be seen that P max and E max of the materials ranges of 5,261 –
11,990 W(att) and of 6.89 – 11.30%. The highest value of 11,990 W is shown by the sample of risk husk – wood
waste briquette (BS) with the lowest efficiency of 6.89%. This result is related to BS used as fuel with the average
temperature of furnace of 250 0C, compared with using BB that reaches 550 0C and BL at 380 0C. This is possibly
due to the high content of ashes in BS (22.34%), where ashes could restrain the process of combustion, so that the
temperature and efficiency of furnace is low.
Table 4.2
Determination of furnace efficiency in the combustion of charcoal and briquette
No
Fuel
Pmax, W
Fmax, kg
Emax,%
Pmin, W
Fmin, kg
Emin, %
1.
Charcoal (AK)
7228
0.44
8.38
1664
0.15
37.24
2.
Sugar cane waste
briquette (BB)
7426
0.52
10.82
1165
0.37
49.60
3.
Rice husk and wood
waste briquette (BS)
11990
0.73
6.89
1104
0.20
50.84
4.
Tanjung Enim coal
briquette (super) (BT)
5261
0.42
10.66
1165
0.42
26.28
5.
Lampung coal
briquette (BL)
5531
0.41
11.30
1629
0.36
26.37
Legend: Pmax : maximum heat energy per weight unit of fuel in Watt;
Emax : furnace efficiency under Pmax
condition in %;
Fmaax : the required quantity of fuel under Pmax condition in kg; P min : minimum heat energy per weight
unit of fuel in Watt;
Emin: furnace efficiency under Pmin condition in %;
F min : the required quantity of fuel
under Pmin condition in kg.
Under the minimum condition, Pmin resulted by fuels of BB, BSD, and BT have the similar value of about
1,100 W, while BL has Pmin similar with AK.
IV.4 Emission of waste gas
SO2, mg/m3
As has been previously explained that combustion of briquette produces disposal gases containing several
materials that could negatively affect either on the worker or the surrounding people. In this investigation,
monitoring on disposal gases on briquette and charcoal combustion is conducted at the the height of 50 cm and 200
cm of the stack above the furnace (as the optimum height where optimum emission is obtained). The results are
shown on Figures 4.3, 4.4 and 4.5 for SO2, NOx and CO gas emissions respectively.
400
300
200
EQS (Emission Quality Standard)
100
0
0
20
AK
BB
BS
40
BT
60
BL
80
100
Time (minute)
waktu,
120
men
Figure 4.3a
EQS and emission of waste gas (SO2) of briquette combustion at the height of 50 am above furnace
SO2, mg/m3
500
400
300
EQS (Emission Quality Standard)
200
100
0
0
20
AK
BB
40
BS
60
BT
80
100
120
Time (minute)
waktu,
BL
menit
Figure 4.3b
EQS and emission of waste gas (SO2) of briquette combustion at the height of 200 am above furnace
On Figure 4.3 it is shown that combustion process using charcoal as fuel is undetectable of the existence of SO2
either at the height of 50 cm or at 200 cm. Al over of the five types of briquette, in this experiment, release SO2 gas
at the initial combustion (0-20 minutes) at the temperature of furnace between 150-600 oC. Furthermore, the content
of SO2 fluctuates up to the minute of 65 th. This fluctuation is presumed due to combustion process of briquette and
charcoal occurring layer by layer. Beyond the minute of 70th all of the fuel used in the combustion process does not
indicate the content of O2, then the temperature tends to decline.
Monitoring at the height of 50 cm above the furnace, briquettes BB and BS exhibit SO2 gas emission
exceeding Emission Quality Standard (EQS), viz. 300 oC. While briquettes BT and BL still meets the EQS. It is
related to the high content of sulfur in briquettes BB and BS of 1.07% and 0.80%, while BT and BL contain lower
sulfur of 0.50% and 0.30% respectively. It is also due to lower temperature of furnace (150-250 oC) compared with
furnace temperature used in the combustion of BB and BL briquettes (300 – 600 oC). At the height of 200 m above
the furnace, BB and BS show SO2 gas emission exceeding EQS, i.e. 300 mg/m3, while BT and BL briquettes
indicate SO2 gas emission below EQS. Result of measuring emission of NOx gas at the heights 50 cm and 200 cm
above the furnace can be seen on Figures 4.4a and 4.4b, respectively.
NOx, mg/m3
Based on the observed data, it can be seen that the same with SO2 emission, NOx emission also exhibits the
same pattern within the first 20 minutes (at between 150 – 600 oC), with the highest concentration of NOx of 220
mg/m3 of BB and BS briquettes at the height of 50 cm above the furnace, and with concentration of 130 mg/m3 at
te height of 220 cm above the furnace. These values are still below the EQS of 1000 mg/m3. While NOx gas
emission in the combustion using AK, BT, and BL fuels shows NOx content still below EQS vale, either at the
height of 50 cm or 200 cm above the furnace.
250
200
150
100
50
0
0
AK
20
BB
40
BS
BT
60
BL
Figure 4.4a
80
100
120
waktu, men
Tim e (m inute)
EQS and emission of waste gas (NOx) of briquette combustion at the height of 50 am above furnace
NOx, mg/m3
150
100
50
0
0
20
40
60
80
100
120
waktu,
menit
Tim e (m inute)
AK
BB
BS
BT
BL
Figure 4.4b
EQS and emission of waste gas (NOx) of briquette combustion at the height of 200 am above furnace
Emission pattern of CO disposal gas of the fuel sample used in this experiment can be seen on Figures 4.5a and
4.5b, each at the height of 50 cm and 200 cm above the furnace. It is indicated that within the first 20 minutes at the
two points of monitoring, AK, BB and BS exhibit emission of CO disposal gas exceeding EQS of 1,000 mg/m3.
This is possibly caused by that the three fuels contains high volatile matters (VM) (> 40%) compared with BT and
BL that contain VM less than 40%. Beyond 20 minutes, CO emission fluctuates and the content still greater than
EQS. This fluctuation is presumed that the combustion process of briquette and charcoal occurs layer by layer.
IV.5 Toxicity of briquette ashes
Besides waste of disposal gas, briquette combustion produces solid waste in the form of ashes. This ash originates
from inorganic compounds is contained as constituent in the main fuel sample, so that it can pollute the environment
because it contains heavy metal elements, and usually this solid waste is disposed just like that. At the removal
location,
CO, mg/m3
environmental problems comes up caused by the condition of the heavy metal elements leached from ash, and
finally pollutes the underground and surface water. To overcome this problem, toxicity of briquette ash should
necessarily be determined, because coal ash is still categorized as dangerous and poisonous materials.
4000
3000
2000
1000
0
0
20
40
60
80
100
120
Waktu, menit
Tim e (m inute)
AK
BB
BS
BT
BL
4.5a
EQS and emission of waste gas (CO) of briquette combustion at the height of 50 am above furnace
Figure
CO, mg/m3
3000
2000
1000
0
0
20
40
60
80
100
120
Waktu,
menit
Time
(minute)
AK
BB
BS
BT
BL
Figure 4.5b
EQS and emission of waste gas (CO) of briquette combustion at the height of 200 am above furnace
In this investigation, chemical composition and its capacity of toxicity of ash resulted from briquette and charcoal
combustion is analyzed by using EPA Method 1311 8). Chemical composition of ash sample is shown on Table 4.3.
Data indicates that the main composition of coal briquette ash is silica (SiO2) and alumina (Al2O3) with the
variation of concentration between 33.7 – 63.9% and 15.48-22.5% respectively. Besides, coal briquette ash BB and
BS contain very high CaO (>24.8%) compared with briquette ash of BT and BL. This is due to that Briquette BB
and BS is made from mixture of coal and biomass ( rice husk and sugar cane waste), while briquette BL and BT is
only made from coal. Is is presumed that CaO is originated from biomass (charcoal contains of 23.4% CaO). The
other oxides in the coal briquette are Fe2O3, MgO, K2O, TiO2 and Na2O with the total concentration of less than
10%. The other available oxides in the coal briquette ash are acid oxides such as SO3 and P2O5.
It can be seen on Table 4.3 that besides the above oxides, coal ash also contains heavy metal elements such as Pb,
Cu and Zn with very low concentration (< 500 ppm).
Data of toxicity test of ash resulted from coal briquette combustion by using EPA Method 1311 can be seen on
Table 4.4. The result of toxicity test of Pb, Cu, Zn elements in coal briquette ash is very low, viz. undetected Pb and
Cu elements between 0 – 16.ppb and Zn between 13 – 286.5 ppb. While Fe and Mn are not as key parameter to test.
Those values are still below the permissible standard limit related to EPA criteria. Then it could be stated that the
ash sample resulted from coal briquette combustion is not included in the category of dangerous and poisonous
materials.
IV.6 The efforts of mitigating gas and solid wastes
In lieu with the UN COP since 2008 it has been tried to launch program of REDD (Reduced Emission from
Deforestation and Degradation), then to encourage program of reducing green house gases including disposal gases
from small industry activity. Briquette is usually utilized in the small industry especially in the developing countries.
So that it is important to try to plant several types of plants that could be able to absorb those disposal gases
produced by industry including small industry.
Table 4.3
Result of chemical analysis of charcoal ash and briquette ash
No
Parameter
Unit
Ash resulted from combustion
AK
BB
BS
BT
BL
1.
SiO2, silicon oxide
%
16,68
33,7
34,9
63,9
52,9
2.
Al2O3, aluminum oxide
%
3,74
15,48
22,5
20,2
22,2
3.
Fe2O3, iron oxide
%
1,33
3,75
2,06
3,40
8,07
4.
TiO2, titanium oxide
%
2,38
0,76
1,69
1,73
1,90
5.
CaO, calcium oxide
%
23,4
29,8
24,8
1,45
0,88
6.
MgO, magnesium oxide
%
4,62
0,86
0,55
0,84
0,63
7.
K2O, kalium oxide
%
18,92
1,65
1,93
1,56
0,34
8.
Na2O, natrium oxide
%
0,82
0,67
0,28
0,56
1,61
9.
MnO, manganese oxide
%
0,11
0,017
0,008
0,017
0,030
10.
SO3, sulfur trioxide
%
2,68
4,18
7,45
1,92
2,80
11.
P2O5, phosphor pentoxide
%
0,046
0,023
0,046
0,093
0,023
12.
LOI, loss on ignition
%
24,7
8,61
3,19
3,76
8,07
13.
Pb, lead
%
0,013
0,020
0
0
0
14.
Cu, copper
%
0,021
0,004
0,004
0,001
0,006
15.
Zn, zinc
%
0,032
0,007
0,005
0,005
0,010
Description: Calculation is based on air dry basis or adb).
Table 4.4
Result of TCLP test of ash of charcoal and briquette
No
Parameter
Unit
TCLP of combustion ash
AK
Standard
BB
BS
BT
BL
EPA, ppm
1.
Pb, lead
ppb
0
0
0
0
0
5
2.
Cu, copper
ppb
0
14.5
16.5
0
4
5
3.
Zn, zinc
ppb
37
13
18
90
286.5
100
4.
Fe, iron
ppb
82
137
121.5
112
108.5
-
5.
Mn, manganese
ppb
23.5
49.5
54
2795
8392
-
Table 4.5 shows that several types of plant are able to absorb several kinds of disposal gases such as COx,
SOx and NOx. This program could be called as REFF (Reduced Emission from Fossil Fuels and Renewable
Wastes).16)
Table 4.5
Area of plants required to absorb CO2 released from coal combustion. 16)
No
1.
2.
3.
4.
5.
2.
3.
4.
5.
Types of plant
1.
Acacia auricliformis
2.
Caliandra calothysus
3. L Leucaena leucacephala
4.
Algizia falcataria
5.
Eucalyptus SP
Area of plant
(Ha)
40,000
62,000
31,000
27,000
20,000
Quantity
of fired coal
(tonne)
2,200,000
2,200,000
2,200,000
2,200,000
2,200,000
Description
- Every combustion of 1 tonne of
Indonesia coal will emit
CO2 2.293 tonnes,
CO 0.073 tonnes,
NOx 0.029 tonnes, and
SO2 0.0086 tonnes.
The domestic consumption of primary energy in Indonesia in 2005 is 843.3 million BOE (263.5 million TCE,
Tonne Coal Equivalent) or about 940.26 million BOE in 2010. Consumption of oil in 2005 was around 129.6 million
TCE and gas and coal being each of 48.7 million TCE and 64.3 million TCE.18) The total fossil fuel consumption is
of about 242.6 million TCE. Using the average quality of oil and coal shown on Table 4.6, the emission of carbon
would be 144.7 million tonnes per annum. 15) This figure is equal to 530.63 million tonnes.of CO2. About 61.02
million tonnes of CO2 emissions came from coal combustion in power generations, cement, and biomass
combustion from small industries rural households.15,17) The biomass fuel consumption of small industry and rural
households might be substituted into briquette (of coal and biomass or mixed). Indonesia constitutes an archipelago
with widespread tropical forest and vegetation. The total area covers 5.2 million km 2, from which 1.9 million km2
consists of land. The rest, 3.3 million km2, is ocean or sea. The forest area is estimated to be about 119.7 million Ha.
On Java island the forest area is of about 3.01 million Ha less than 30% of the Java area of land (the required
minimum percentage area of forest). Assuming that the total absorption of the forest to be 121 tonnes CO 2 per Ha
per year (Acacia auriculiformis), the area of forest or vegetation needed to absorb the 530.63 million tonnes of CO 2
emission per annum from consumption of all fossil fuel in Indonesia is about 4.41 million Ha in Indonesia.
Compared with the world emission, from fossil fuel Indonesia as the 14 th country of the world contributes about
1.4% of the total CO2 emission (Carbon Dioxide Information Analysis Center (CDIAC), 2004 collected in 2007).
For Java island as the densest population and industry region in the country (area of about 132,000 km2 or about 7%
of the Indonesia area of land), around 26 million tonnes of coal consumption for power plant and cement industry
would result in the emission of 56.8 million tonnes of CO2 per year. And to absorb 56.8 million tonnes of CO 2
emission just from coal combustion in Java needs about 0.47 million Ha of forest. 15,18) The forest area which can
absorb and reduce the accumulation of CO2 in the atmosphere is now decreasing in Java island. In addition, the
combustion of other fossil fuels (oil and gas) will also increase.
Table 4.6
The average ultimate quality of Indonesia oil and coal
No
Analysis
Oil (%) *)
Coal (%)
1.
Moisisture
0.90
15.0
2.
Sulfur
0.012
6.43
3.
Hydrogen
0.19
0.61
4.N
Nitrogen
11.20
5.67
5.C
Carbon
0.45
0.91
6.
87.25
63.00
*) Oil and Gas Technology Research and Development Center, Indonesia Ministry of Energy and Mineral
Resources.
Related to this investigation on briquette combustion, the estimated consumption of agricultural waste and
forest waste (biomass) for small industry (4.4 million TCE per annum) and rural households in Java in total is of
about 17.5 million TCE per annum, and of about 37.5 million TCE per annum in Indonesia. 17) In Java, for mitigating
CO2 emitted from small industry and rural households that usually uses briquette (of biomass, coal or mixed), area
of forest of 31,819 Ha is required, out of other industries (power plants, manufacturing and urban households) and
transportation requirement. Installment of stack system based on standard operating procedure (SOP) is required by
every furnace or complex of furnaces in the small industry to absorb waste gases and fly ashes resulted from
briquette (or biomass) fuel combustion. Although the absorbing capacity of the existing forest in Java (i.e. of around
3.01 million Ha) is not known, the CO2 emitted by coal combustion is considered to be significant problem to the
green house effect, however since Java island is surrounded by ocean which can assist to absorb CO2 from the
atmosphere. Moreover, the existing power generation (Suralaya, Tanjungjati and Paiton located in Java island) is on
the seaside. The increasing projection of coal utilization in the future as the effort of substitution for oil fuel, coal
utilization technologies which can reduce CO2 emissions as well particulate waste are considered to be the best way
to solve the problem of green house effect.
V. CONCLUSION AND RECOMMENDATION
V.1 Conclusions
Based on the result of research data, several conclusions could be drawn as the followings:
a. The briquette fuel used in this investigation contains moisture and volatile matters lower than charcoal, while ash
and fixed carbon content is higher.
b. Sugar cane waste briquette indicates the highest temperature of furnace (around 605 oC compared with other
briquettes and charcoal.
c. By using water boiling water method, the increase of water temperature for the five kinds of fuel is similar, even
though the experiment by using sugar cane waste the boiling of water is faster than the others. The boiling time by
using the briquette occurs at the 22 nd minute.
d. Heat energy per unit time under the maximum condition resulted by rice husk briquette (BS) indicates the higher
value (11,990 W(att) per 0.73 kg of sample). While sugar cae waste briquette indicates per time unit equals
charcoal, viz. 7,426 W (per 0.52 kg of sample) and 7,228 W (per 0,44 kg of sample) and the briquettes BT and BL
indicate energy per time unit of 5,261 W (per 0.42 kg of sample) and 5,531 W (per 0.41 kg of sample). Heat energy
per time unit under the minimum condition, the five types of fuel indicates the similar level of around 1,104 – 1,664
W.
e. Under the maximum condition, the furnace efficiency of charcoal (AK) is 8.38%, and the four types of briquette is
of around 6.89-11.30 %. While under the minimum condition, the furnace efficiency of charcoal (AK) is of 37.24 %
and the other briquettes are between 26.28 – 50.84%.
f. Emission of the disposal gases of the five types of fuel, in general, shows the similar pattern (up to the minute of
20th) , where at the temperature of 150-600 oC gas emission of SO2 of BB and BS has exceeded EQS (environmental
quality standard, 300 mg/m3). While emission of NOx and CO of all the samples exhibits still under EQS. Based on
this preliminary investigation, it can be concluded that briquettes BL and BT exhibit better in term of its emission of
pollutant gas. Safety of the briquette utilization requires further investigation of gas emission effect on human
health.
g. Ashes resulted from briquette combustion could be categorized as not dangerous and poisonous material according
to the US EPA standard.
h. Related to this investigation on briquette combustion, the estimated consumption of agricultural waste and forest
waste (biomass) for small industry (4.4 million TCE per annum) and rural households in Java in total is of about
17.5 million TCE per annum, and of about 37.5 million TCE per annum in Indonesia. In Java, for mitigating CO2
emitted from small industry and rural households that usually uses briquette (of biomass, coal or mixed), area of
forest of 31,819 Ha is required, out of other industries (power plants, manufacturing and urban households) and
transportation requirement.
V.2. Recommendations
To obtain more accurate and complete data, it is required:
a. Investigation on furnace efficiency by using various types of furnace to find out its modification toward
environmental friendly.
b. Influence of briquette combustion on human (user) health.
c. Investigation on pollution of organic material product of combustion on human health.
d. Test of toxicity on briquette ash from the side of biological living.
e. Investigation on coal ashes in the purpose of its possible potential utilization (as conditioner, building
materials, etc.).
f. It is necessary to investigate the green house gas (GHG) absorption capacity of the available Indonesia forest,
particularly in Java island, and the necessity to enlarge it to meet the demand of mitigating effect of GHG due to the
ever increasing GHG in the atmosphere in the coming years.
References
1. Badan Koordinasi Energi Nasional, 1990. Kebijaksanaan Umum Bidang Energi, Jakarta, April 1990. (National
Energy Coordination Board, 1990. General Policy on Energy).
2. Gandataruna K., 1993. Pembangunan Pertambangan Yang Berwawasan Lingkungan, Disajikan dalam Seminar
Nasional Integrasi Ekologi dan Ekonomi dalam Pembangunan dan Pengolahan Sumberdaya Alam, ITB,
Bandung, 7-8 Juni 1993. (Mining development with environmentally outlook. Seminar on Integration of
Ecology and Economy in Natural Resource Development and Utilization).
3. Ballard-Tremeer, G. , 1997. Emissions of Rural Wood-Burning Cooking Devices, http://ecoharmony.com.
4. Mangunwijaya, 1991. The Development of Environmental Management For Mining Activities In Indonesia ,
Paper Presented at Seminar on Mining Activities and Environment Management, Bandung, July 2-4, 1991.
5. Hitoshi, H., Yoko, W., Tomoyuhi, K., and Kanji, Y., 2001. Bio-coal Briquette and Planting Trees as and
experimental CDM in China, Paper presented at the Annual Meeting of Society for Environmental
Economics and Policy Studies, September 29 –30, 2001, Japan.
6. Tunggal, A.D, 2001. Peraturan Perundang-Undangan Lingkungan Hidup. Buku VI, Harvarindo. (Law and
Regulation on Environment).
7. Biomass Technology Group, 2003. Testing Protocol, March 2003.
8. Environmental Protection Agency, 1995. Toxicity Characteristics Leaching Procedure, SW 846, Method 1311.
9. Sheps-Pelleg, S., Cohen, H., 1998. Evaluation of the Leaching Potential of Trace Elements from Coal Ash to the
Groundwater Aquifer, Fly Ash Library Home: www.flyash.info
10. Tami Bond, Stove Testing Recommendation, 2002. ETHOS meeting, Seattle, Washington, January 12, 2002
11. FAO Regional for ASEAN, 1993. Improved Solid Biomass Burning Cook-stoves – Development Manual.
12. Environment Australia, 1999. Emission Estimation Technique Manual – Agregated Emissions from Domestic
Solid Fuel Burning.
13. Staton, D.M., and Harding, M.H., 1998. Health and Environmental Effect of Cooking Stove Used in Developing
Countries, Env. Research, October 1998.
14. Chen, Y., Pew, D., Abbott, 1997. Cook Stove Efficiency, Health and Impacts, Biomass Lab. Report.
15. Soelistijo, U.W., cs, 1991. The effects of gas emissions from coal fired power generations and cement industries
on the environment in Indonesia, case histories from Java island. “IEA/OECD Conference on Coal, the
Environment and Development : Technoloies to Reduce Greenhouse Gas Emissions”, 18 th – 21st November,
1991, Sydney, Australia.
16. Soelistijo, U.W., 1990. Usaha-usaha pemanfaatan batubara dan dampahnya terhadap lingkungan. “Konferensi
Energi III 1990”, Universitas Sriwijaya, Palembang, 5 -6 Juli 1990.(The efforts of coal utilization and its
impacts on environment).
17. Sulasmoro, B., Soelistijo, U.W., cs, 1989. Preliminary study on coal demand potential in small industry and
household sectors and policies for developing the potential in Indonesia. Mineral Technology Development
Center, Ministry of Mines and Energy Indonesia and The Institute of Energy Economics Japan.
18. Anonymous, 2007. Indonesia Mineral, Coal Geothermal and Groundwater Statistics 2007. Directorate Program
Supervision of Mineral, Coal, and Geothermal, Directorate General of Mineral, Coal and Geothermal,
Ministry of Energy and Mineral Resources.
ACKNOWLEDGEMENT
This paper is made possible through the cooperation between Mineral and Coal Technology Research Center
(MCTRDC), Ministry of Energy and Mineral Resources, and Bandung Islamic University, Indonesia. This paper is
submitted to Air Quality VIII, An International Conference on Carbon Management, Mercury, Trace Substances,
SOx, NOx, and Particulate Matter, October 24-27, 2011, Arlington, VA, USA held by Energy and Environment
Research Center Grand Forks, North Dakota, USA. High appreciation is delivered to the Committee of the
International Conference. This paper is supported by Low Carbon Development Project - UK Department for
International Development (DfID) and Ministry of Finance Republic of Indonesia.
Bandung , January 2011.