“Coal Quality Evaluation System( C-QUENS )” developed by Gifu University, Japanese National University, was used in this study to clarify the potential of reduction of CO2 emission by reducing low rank coal moisture in advance by utilizing STD that is a high efficiency coal drying technology combined with power plant on the utilization of heat.
The object of this study is to confirm i) an applicability of coal drying technology for Indonesia low rank coal, ii) potential of CO2 reduction by reducing low rank coal moisture, iii) economics and finance scheme on pre-drying of low rank coal, iv) development of methodology of CO2 reduction by pre-drying of low rank coal, v) bilateral carbon offset mechanism, vi) promotion of STD in Indonesian market.
3. Relationship between Japan and Indonesia
In the year of 2010, the export amount from Indonesia to Japan and from Japan to Indonesia were 2,462.9 billion and 1,393.5 billon Japanese yen, so the trade between Japan and Indonesia is an excess of export from Indonesia to Japan. Indonesia is one of the most important countries for Japan for energy security. Indonesia is accounted for 20% of LNG (rank 1st), 19% of coal (rank 2nd) and 2% of oil in Japanese import. Indonesia is the biggest oil producer in SE Asia and was a member of OPEC since 1962 but in 2004, Indonesia became a net importer of oil and then left OPEC in 2009 because of the exponential growth of oil consumption in line with economic development and population growth.
In the year of 2010, the direct investment from Japan to Indonesia was 710 million US dollar that was forth ranking in the World. There are over 1,300 Japanese private enterprises being incorporated in Indonesia and hold over 320,000 Indonesian workers by the direct investment until now. Japan has been the biggest official development aid provider to Indonesia over the years and free financial aid, loan assistance and technical aid were 3,440 million, 113,900 million and 7,990 million Japanese yen in 2009. The economic partnership agreement (EPA) between Japanese and Indonesia became effective in 2008 and Japan has good relationship with Indonesia in politically and economically.
4. Background of CO2 reduction in Coal Power Plant 1) Mitigation of GHG in Indonesia
The green house gas (GHG) emission achieved 2.1 billion ton per year in 2005 mainly reason of forest loss and peat land devastation and is expected to achieve 3.3 billion ton per year in 2030 in the case of no countermeasure.
Table 4-1 shows the source and amount of GHG emission in Indonesia. The power consumption is expected to increase at 9% per annum until 2030 in line with rapid economic growth by increase of GDP at over 6% per annum in Indonesia. In 2009, Indonesia had 30 gig watts (GW) of installed power generation capacity and national electrification ratio was 66% and Indonesia plans to achieve 55GW of installed power generation capacity and 91% of electrification ratio in 2019. The installed power generation capacity is expected to be required 100 GW in 2030.
The faster growing of GHG emission over the last decade is due to the increase of coal power generation in Indonesia. The CO2 emission in power sector is expected to increase from 110 million ton per year in 2005 to 810 million ton per year in 2030 that will be higher than that of peat land devastation. The reduction of CO2 emission from coal power plant becomes important against global warming. Indonesia established the National Council of Climate Change (DNPI) in 2008 to combat global warning and the strategies proposed are follows.
Work towards the implementation of a carbon tax/levy on fossil fuel combustion, in parallel with removal over time of energy subsidies. Couple this policy with access to international carbon markets, by negotiating a
“no-lose” target with appropriate parameters.
Introduce complementary measures to incentivize energy efficiency and deployment of low-emissions technology, exemplified by a specific geothermal policy strategy.
Support the creation of new, broad-based carbon market mechanisms like sectoral targets and crediting.
Support new and additional sources of international public financing. Ensure adequate returns for Indonesia’s emissions reductions.
Strengthen capacity for climate policy analysis at the Ministry of Finance. Support policy coordination across government especially among the economics ministries; and advocate a review of the broader regulatory framework that relates to climate change policy.
Table 4-1 Source and Amount of GHG emission in Indonesia (million ton-CO2)
2) Overview of Power Generation in Indonesia
Total installed power generation capacity was 29,370MW and coal power capacity was 11,180MW of which share was 40% in 2009. Indonesian planned to build 10GW coal power plant (1st Crash Program) in 2006. This program was not only for supplying power demand, but also avoiding costly oil fired power generation. At present PLN (state owned power company) is building 33 coal power plants and all construction work will be completed in 2013. Indonesia issued 2nd crush program in January, 2010 for building additional 10GW power plant, consisting of LNG, Coal and Renewable.
2nd crush program is planned to be completed until 2014. Additional 10,677MW consists of PLN’s 6,415MW and IPP’s 4,262MW and investment cost is calculated USD 7,605MM and USD8, 450MM respectively. Coal fired 4,294MW, geothermal 3,583MW, LNG 1,626MW and micro-hydro 1,174MW are to be build. Indonesia committed target “26% GHG reduction by 2020”, Clean energy and high efficiency coal fired power plant will be key to fulfill the target. Table 4-2 and 4-3 show the installed, constructing and planning coal power plant of PLN and IPP in Indonesia.
Table 4-2 Coal fired power plant of PNL
Year 2005 2020 2030
Building 23 31 36
Cement 23 45 75
Oil&Gas 96 103 105
Agriculture 129 143 151
Transportation 60 222 442
Power 110 370 810
Forest 760 650 590
Peat 850 970 1,050
Total 2,051 2,534 3,259
Table 4-3 Coal fired power plant of IPP
3) Overview of Coal Production in Indonesia
Indonesian coal resources is 104.9 billion ton and minable coal reserves is 21.1 billion ton in the end of 2009.
Coal resources consist of 12% of bituminous coal (moisture under 20%, C.V. over 5,800kcal/kg), 67% of sub-bituminous coal (moisture 20-35%, C.V. 4,200-5,800kcal/kg) and 20% of lignite (moisture over 35%, C.V.
under 4,200kcal/kg) is 20%. Total share of Low Rank Coal such as sub-bituminous and lignite is 87% of all coal deposit. In 2009, Indonesia became No. 6 coal producer in the world and No. 1 coal producer in Asia-Pacific area.
Domestic coal demand is mainly made by 3 sectors, power, cement and other industries. The coal demand for power generation occupied 65% of total demand. The coal consumption of PLN in 2010 was 4.9million ton of bituminous, 27.7million ton of sub-bituminous and 8.2million ton of lignite. In the finishing year of 2nd crush program, PLN’s consumption of coal will achieve 8.8million ton of bituminous, 42.1million ton of sub-bituminous and 44.3million ton of lignite.
Table 4-4 PNL coal fired plant consumption
PLN Capacity
Unit Capacity（MW) Unit No. Total（MW) UnitNo. Total（MW) Unit No. Total（MW) Total（MW)
660 1 660 1 660 1,320
625 1 625 625
600 3 1,800 1 600 2,400
400 6 2,400 2,400
350 3 1,050 1,050
330 1 330 2 660 990
315 3 945 4 1,260 2,205
300 2 600 2 600 1,200
<300 14 542 44 1,944 31 171 2,657
Total 31 7,902 57 6,774 31 171 14,847
Operation Construction Planning(～2014)
IPP Capacity
Unit Capacity（MW) Unit No. Total（MW) Unit No. Total（MW) Unit No. Total（MW) Total（MW)
1,000 2 2,000 2,000
815 1 815 815
660 3 1,980 1 660 1 660 3,300
650 2 1,300 1,300
615 2 1,230 1,230
400 2 800 800
300 4 1,200 1,200
<300 0 0 36 1,447 117 4,347 5,794
Total 7 4,510 38 2,922 126 9,007 16,439
Operation Construction Planning(～2019)
Calorific Value Total
(kcal/kg) 2010 2011 2012 2013 2014 2010-2014
4,200 8.2 25.8 32.2 35.4 44.3 145.9
5,100 27.7 28.7 36.9 43.2 42.1 178.6
6,100 4.9 4.9 8.9 8.9 8.9 36.5
Total 40.8 59.4 78.0 87.5 95.3 361.0
Source : PLN May, 2010
Expected Coal Consumption (million ton)
Considering coal export as a way of the foreign currency revenue source, it is preferable that abundant and un-exportable low rank coal is to be used in domestically. In December 2009, in order to ensure coal supply to domestic market, Minister of Mines and Energy issued circular for Domestic Market Obligation (DMO). DMO 2011 is 78,970thousand ton the number is 24.2% total production domestically. In 2010, annual export amount from Indonesia reached 240million ton. The 1st destination of export is China, 2nd is India, 3rd is South Korea and Japan is 4th country. In April 2011, PLN requested Indonesian government to prohibit the export of low rank coal (under 4,200kcal/kg). In consequence, Indonesian government indicates willingness to go forth the regulation for export by 2014. Introducing STD to Power plant and drying low rank coal, it can be improved calorie and upgraded. This will allow switching to distinguish fuel use coal from export coal. Then STD contributes to fuel ensuring and export control for low rank coal.
5. Steam Tube Dryer (STD) for Indonesian low rank coal 1)STD for drying application test
STD batch and continuous tests were executed at Tsukishima Kikai, for acquiring of STD application and scale-up data using A-Coal (Moisture content ; 31.6% and Calorific value ; 4,407kcal/kg(ar)) and B-Coal (Moisture content ; 43.6% and Calorific values ; 3,500kacl/kg(ar)) from Indonesia. Figure 5-1 shows the outline of the STD continuous test machine.
Figure 5-1 Flow sheet for of STD continuous test
According to results of STD batch and continuous tests with A-Coal and B-Coal, it was confirmed that STD is highly applicable to dry for these low rank coals. As STD can dry them to approx. 5wt% against target moisture approx.10wt%, STD can achieve the appropriate drying speed without coal properties change after drying and adhesion of coal on tube and shell surfaces of STD.
2) Commercial plant and construction cost of STD
The commercial plant of STD system is studies for No.2 unit (400MW), No.7 unit (600MW) and No.8 unit (625MW) of Sularaya power plant and No.1 unit (300MW) of Labuan power plant, based on drying test result.
The process flow, layout drawing of STD system were shown as follows .
Additionally, the required number of STD unit, utility condition/consumption and construction cost of STD were roughly estimated. Figure 5-2 shows the STD application flow for coal power plant.
Dust
Drain
Bag Filter
PG PG
TR
TR
TI TI TI
TR
TR
TR
3.1m2 STD
Air
TI
Dried Coal
Exhaust gas Steam
Wet Coal
Figure 5-2 STD application flow for coal power plant
Figure 5-2 STD application flow for coal power plant
Existing coal moisture contents used for Suralaya power plant are 25.5% (Calorific value;5,025kca/kg(ar)) in No.2 unit (400MW) and 25.1% (Calorific value :5,096kcal/kg (ar)) in No.7 unit (600MW). Because No.8 unit (625MW) in Suralaya and the No.1 unit (300MkW) in Labuan use fuel coal as A-Coal, moisture content of A-Coal : 31.6% (Calorific value ;4,407kcal/kg(ar)) at drying test is representative value. In the future, the cheaper and higher moisture coal would be procured as fuel coal. Accordingly, B-Coal (43.6wt% Calorific value ;3,483kcal/kg(ar)) available for procurement and using drying test is adopted for fuel coal. Specification, the required unit number, the maintenance cost, and construction cost of STD were estimated by drying of coal moisture content; 10%. Table 5-1 shows these results.
Table 5-1 Required STD unit numbers at each case.
If the moisture content of coal is increased and/or the power plant capacity grows, the required number of STD unit will increase by evaporation volume rise.
6. Impacts of the STD system on plant performances (Process simulation by C-QUENS)
Coal Quality Evaluation System (C-QUENS) is a process simulator for pulverized coal fired power plants that can estimate various plant performances such as the thermal efficiency, consumption power, and the combustion characteristics for any coals. For Suralaya power station and Labuhan power station, the plant performances with and without the STD system were predicted by the C-QUENS for some current coals used and B-Coal which will be used in feature. The numerous specifications of each power plant were inputted into the C-QUENS as boundary conditions, and new process lines for process steam of the STD system were added on the C-QUENS.
Coal Power Plant Unit No.
Power Generation Capacity (MW)
Drying (Coal Moisture %) 31.6→10 43.6→10 25.5→10 43.6→10 25.1→10 43.6→10 31.6→10 43.6→10
Required STD Unit Number 1 2 1 3 2 4 2 4
STD Construction Cost (US million $) 21.7 42.6 21.6 63.9 41.3 84.8 42.6 84.8 STD Maintenance Cost (US million $/y) 0.25 0.50 0.25 0.75 0.50 1.00 0.50 1.00
Labuhan Unit1 Suralaya Unit2 Suralaya Unit7 Suralaya Unit8
300 400 600 625
Boiler feed water、Drain Carrier gas、Exhaust gas
Coal Steam
Air、Exhaust combustion gas Existing power plant flow
STD Drying system
Condenser Low Rank Coal
Crusher
STD
Bag Filter
Boiler
Pulverizer
Turbine・
Generator
Carrier gas (Air)
Low Pressure Steam Exhaust gas
Air
Exhaust combustion gas
Drain
1) Drying case of some current coals used
Table 6-1 summarizes the results of effectiveness of the STD system for each power plant. When the STD system was added to power plants, it estimated that the thermal efficiency of the boiler was significantly increased due to the decrease of the amount of moisture generated from coal combustion. Therefore, the gross thermal efficiency was increased, while the coal feed rate and CO2 emission were decreased for all units as listed in Table 6-1.
In the simulation, the necessary steam and electricity of the STD were precisely concerned in the simulation for each unit. If the STD system is installed to the power plant, drying coal having low moisture (10%) decreases auxiliary electricity of power plants such as mills power and fans power (PAF, FDF, and IDF). These electricity saving was just corresponded to the electricity consumption of the STD for all simulation cases. To reduce the necessary steam power of the STD, the efficiency heat recovery and exchange system were employed. In this system, the necessary bleeding steam from the low pressure turbine of the power plants can save in the range from 20% to 50%.
All cases considered, an impact of boiler scales on the gross thermal efficiency was strong, for example, the largest power plant (Suralaya No.8 unit, 625 MW) has much advantage in the thermal efficiency, reduction of coal consumption, and CO2 emission. By the STD system installation, the improved gross thermal efficiency in Labuan No.1 unit (300MW, raw coal moisture = 31.6%), in Suralaya No.2 unit (400MW, raw coal moisture = 25.5%), in Suralaya No.7 unit (600MW, raw coal moisture = 25.1%), and in Suralaya No.8 unit (625MW, raw coal moisture = 31.6%) was 0.67, 0.15, 0.85, and 1.06 point, respectively. The improved point in Suralaya No.2 unit was lower than that of other units, because the original gross thermal efficiency in Suralaya No.2 unit was lower than that of other unit. In the case of annual operation 8,000 hours (333 days per year), the reduction of coal consumption in Labuan No.1 unit, in Suralaya No.2 unit, in Suralaya No.7 unit and in Suralaya No.8 unit was 24,800 ton, 5,600 ton, 47,200 ton and 72,000 ton, respectively. At once, the reduction of CO2 emission in Labuan No.1 unit, in Suralaya No.2 unit, in Suralaya No.7 unit and in Suralaya No.8 unit was 41,600 ton, 12,000 ton, 95,200 ton and 123,200 ton, respectively.
In conclusion, installation of the STD system in power plants give advantages in the reduction of coal consumption, the improvement of gross thermal, and the reduction of CO2 emission.
Table 6-1 Impacts of the STD system installation to each power plant (for current coals used)
2) Drying case of a high moisture content coal (B-Coal)
It predicts that B-Coal having high moisture content will be used some coal fired power stations in near future.
Therefore, the simulation was performed for B-Coal (moisture = 43.6%) under the same calculation conditions as the above simulations. Table 6-2 summarizes the simulation results for B-Coal which show great advantages in effective terms of plant characteristics. By the STD system installation, the improved gross thermal efficiency in Labuan No.1 unit (300MW), in Suralaya No.2 unit (400MW), in Suralaya No.7 unit (600MW), and in Suralaya No.8 unit (625MW) was 1.26, 0.90, 1.57, and 1.50 point, respectively. In the case of annual operation 8,000 hours (333 days per year), the reduction of coal consumption in Labuan No.1 unit, in Suralaya No.2 unit, in Suralaya No.7 unit and in Suralaya No.8 unit was 62,400 ton, 59,200 ton, 140,800 ton and 138,400 ton, respectively. At once, the reduction of CO2 emission in Labuan No.1 unit, in Suralaya No.2 unit, in Suralaya No.7 unit and in Suralaya No.8 unit was 86,400 ton, 80,800 ton, 193,600 ton and 190,400 ton, respectively. In these case studies, it found that the impacts of the STD were increased with an increase in moisture content in coals.
Power Plant Unit No.
Capacity (MW)
Coal Moisture（％） 31.6 25.5 25.1 31.6
Dried Coal Moisture（％） - 10 - 10 - 10 - 10
Coal Calorific Value (Kcal/Kg) 4,407 5,799 5,025 6,066 5,096 6,122 4,407 5,799 STD's Effects
Transmission End Efficiency （％） 35.40 36.07 36.04 36.19 37.61 38.46 37.21 38.27 Generating Efficiency Up (Point） - 0.67 - 0.15 - 0.85 - 1.06
Coal Consumption (t/h) 165.4 162.3 184.3 183.6 269.2 263.3 327.8 318.8
Coal Consumption Reduction (t/h) - 3.1 - 0.7 - 5.9 - 9.0
CO2 Emission (t/h) 281.1 275.9 357.5 356.0 536.1 524.2 557.3 541.9
CO2 Emission Reduction (t/h) - 5.2 - 1.5 - 11.9 - 15.4
STD Operation Conditions
Required STD Unit Number - 1 - 1 - 2 - 2
Required Steam Conditions
Temperature（℃） - 177 - 175 - 186 - 184
Pressure（MpaG） - 0.83 - 0.82 - 1.04 - 1.00
Quantity (t/h) - 46.1 - 38.1 - 27.2x2 - 43.8x2
Returning Flocculated Water
Temperature （℃） - 136 - 138 - 150 - 146
Pressure (MpaG) - 0.83 - 0.82 - 1.04 - 1.00
Flow (t/h) - 46.1 - 38.1 - 27.2x2 - 43.8x2
Utilities
Power (KW) - 620 - 620 - 340x2 - 570x2
N2-Pressure 0.6MpaG-(Nm3/h) - 360 - 390 - 200x2 - 350x2
Instrument Air -Press. 0.5MpaG-(Nm3/h) - 180 - 180 - 180x2 - 180x2 Construction Cost (US$) - 21,700,000 - 21,600,000 - 41,300,000 - 42,600,000 Annual Maintenance Cost(US$/y) - 250,000 - 250,000 - 500,000 - 500,000 Economical Evaluation
Annual Operation Hours 8,000 8,000 8,000 8,000 8,000 8,000 8,000 8,000
Annual Coal Consumption (t/y) 24,800 5,600 47,200 72,000
Annual CO2 Emission Reduction (t/y) 41,600 12,000 95,200 123,200 Coal Cost (CIF US$/t) 73.23 73.23 80.39 80.39 78.26 78.26 73.23 73.23
CO2 Credit (US$/T) 30 30 30 0
Annual Coal Consumption Reduction (US$/y) 1,816,104 450,184 3,693,872 5,272,560
Annual CO2 Credit Amount (US$/y) 1,248,000 360,000 2,856,000 0
Annual Benefit (US$/y) 3,064,104 810,184 6,549,872 5,272,560 Annual Operation Cost (US$/y) 450,000 450,000 700,000 700,000
Year of Depreciation 8.3 60.0 7.1 9.3
Lahuhan Unit1 Suralaya Unit2 Suralaya Unit7 Suralaya Unit8
300 400 600 625
Table 6-1 Impacts of the STD system installation to each power plant (for high moisture content coal)
Figure 6-1 depicts relation between electricity generation of the power plants and the reduction of CO2 emission as a parameter of moisture content in a coal for Labuan power plant. Where, moisture content after drying was assumed 10% in the simulation. It found that an increase in electricity generation and moisture content were decreased the amount of CO2 emission.
Power Plant Unit No.
Capacity (MW)
Coal Moisture（％） 43.6 43.6 43.6 43.6
Dried Coal Moisture（％） - 10 - 10 - 10 - 10
Coal Calorific Value (Kcal/Kg) 3,483 5,558 3,483 5,558 3,483 5,558 3,483 5,558 STD's Effects
Transmission End Efficiency （％） 33.97 35.23 34.16 35.06 35.64 37.21 35.82 37.32
Generating Efficiency Up (Point） - 1.26 - 0.9 - 1.57 - 1.5
Coal Consumption (t/h) 218.0 210.2 289.1 281.7 415.7 398.1 430.8 413.5
Coal Consumption Reduction (t/h) - 7.8 - 7.4 - 17.6 - 17.3
CO2 Emission (t/h) 300.1 289.3 397.8 387.7 572.1 547.9 592.9 569.1
CO2 Emission Reduction (t/h) - 10.8 - 10.1 - 24.2 - 23.8
STD Operation Conditions
Required STD Unit Number - 2 - 3 - 4 - 4
Required Steam Conditions
Temperature（℃） - 177 - 135 - 186 - 184
Pressure（MpaG） - 0.83 - 0.82 - 1.04 - 1.00
Quantity (t/h) - 44.3X2 - 38.9X3 - 41.9X4 - 42.3X4
Returning Flocculated Water
Temperature （℃） - 134 - 135 - 147 - 144
Pressure (MpaG) - 0.83 - 0.82 - 1.04 - 1.00
Flow (t/h) - 44.3x2 - 38.9x3 - 41.9x4 - 42.3x4
Utilities
Power (KW) - 580x2 - 320x3 - 520x4 - 550x4
N2-Pressure 0.6MpaG-(Nm3/h) 360x2 130x3 340x4 350x4
Instrument Air -Press. 0.5MpaG-(Nm3/h) 180x2 180x3 180x4 180x4
Construction Cost (US$) - 42,600,000 - 63,900,000 - 84,800,000 - 85,200,000 Annual Maintenance Cost(US$/y) - 500,000 - 750,000 - 1,000,000 - 1,000,000 Economical Evaluation
Annual Operation Hours 8,000 8,000 8,000 8,000 8,000 8,000 8,000 8,000
Annual Coal Consumption (t/y) 62,400 59,200 140,800 138,400
Annual CO2 Emission Reduction (t/y) 86,400 80,800 193,600 190,400 Coal Cost (CIF US$/t) 59.4 59.4 59.4 59.4 59.4 59.4 59.4 59.4
CO2 Credit (US$/T) 0 0 0 0
Annual Coal Consumption Reduction (US$/y) 3,706,560 3,516,480 8,363,520 8,220,960
Annual CO2 Credit Amount (US$/y) 0 0 0 0
Annual Benefit (US$/y) 3,706,560 3,516,480 8,363,520 8,220,960 Annual Operation Cost (US$/y) 700,000 950,000 1,200,000 1,200,000
Year of Depreciation 14.2 24.9 11.8 12.1
Lahuhan Unit1 Suralaya Unit2 Suralaya Unit7 Suralaya Unit8
300 400 600 625
Fig. 6-1 Effect of boiler scale and moisture content on the reduction of CO2 emission by the STD system installation.
7. Economic Evaluation
This evaluation has been made for No.2 unit (400MW), No.7 unit (600MW) and No.8 unit (625MW) of Suralaya and No.1 unit (300MW) of Labuhan respectively. Table 7-1 and 7-2 show assumptions of each case. Those tables contain annual reductions of coal purchase cost and depreciation period of STD.
Table 7-1 Economic overview of Labuhan No.1 unit and Suralaya No.2 unit
Table 7-2 Economic overview of Suralaya No.7 unit and No.8 unit