Reducing Mercury Emission from Coal Combustion in the Energy Sector in Thailand Presented by Faculty of Public Health, Thammasat University November 7, 2017

Topics I. Introduction II. Coal information III. Coal-fired power plant information IV. Coal sampling and analysis V. Future mercury emission estimation

I. Introduction

I. Mercury Cycle Source: http://www.mercury.utah.gov/atmospheric_transport.htm

I. How do Coal-Fired Plant Work? Coal Supply Conveyer Pulveriser /Mill Boiler Ash Systems Water Purification Stack Condenser Substation/ Transformer Generator Steam turbine Electricity Source: https://www.worldcoal.org/coal/uses-coal/coal-electricity

II. Coal Information

II. Coal information : Type of coal and its utilization in Thailand Lignite Bituminous Sub-bituminous Anthracite Lignite is the most common coal produced in Thailand. It is commonly used for electricity generation, but not widely used in industry because it contains lower energy and higher pollution comparing with other coal types. Anthracite, bituminous, and sub-bituminous which are used in industrial processes and electricity generation are mainly imported from Indonesia and Australia (Thai Custom Department, 2017).

II. Coal information : Coal consumption in Thailand In 2016, coal and lignite are consumed around 38,457,405 tons, with 64% for electricity, and the rest for industry. Most of domestic lignite (97%) was used in electricity generation, whereas imported coal (60%) was mainly used in industrial processes. Industry Electricity The share of coal consumption for electricity generation was significantly increased to 35% in 2016, lignite is still the main material for Thai coal power plant (around 65%). The amount of lignite used in coal-fired power plant is stable within around 16,000,000 to 18,000,000 tons per year during the last decades.

III. Coal Fired Power Plant Information

III. Coal fired power plant : Situation of electricity generation in Thailand Main electricity producers are the EGAT (Electricity Generating Authority of Thailand), the IPPs (Independent Power Producers), the Small Power Producers (SPPs) and the Very Small Power Producers (VSPPs). Total capacity of the existing coal-fired power plants in Thailand with the rate of 8,704 MW. The two largest power plants operated in the country belong to the Mae Moh power plant and the BCLP power plant with the total installed capacities of 2,180 and 1,434 MW, respectively. Electricity production capacity sorted by Producer

III. Coal fired power plant : National and Provincial Air Pollution Control and Operational Efficiency List Air Pollutants NOx SO2 PM APC Technology Low NOx Burner (LNB), Over Fired Air (OFA) Selective Catalytic Reduction (SCR) Flue Gas Desulfurization (FGD) using Limestone or Seawater Electro Static Precipitator (ESP) Bag Filter Operational efficiency 63.6%-95.0%. 77.5%-97.0% 99.3%-99.9%.

IV. Coal Sampling and Analysis

Oxygen Bomb Combustion/ Ion Chromatographic Method IV. Coal sampling : Analysis Methods for Coal Sample Parameter Analysis Method 1) Proximate Analysis   Total Moisture ASTM D3302/D3302M-12 Inherent Moisture ASTM D7582-15 Volatile Matter Fixed Carbon Ash 2) Ultimate Analysis Carbon(C) ASTM D5373-16 Hydrogen(H) Nitrogen(N) Sulfur(S) ASTM D4239-14 Oxygen(O) Calculation Parameter Analysis Method 3) Chemical Composition   Mercury (Hg) ASTM D6722-11 Arsenic (As) ASTM D6357-11 Selenium (Se) Sodium (Na) Calcium (Ca) Barium (Ba) Chlorine (Cl) ASTM D4208-13 Bromine (Br) Oxygen Bomb Combustion/ Ion Chromatographic Method

IV. Coal sampling : Analysis Methods for mercury in coal and coal combustion product Substance Analysis Method Pulverized coal ASTM D6722-11 Bottom ash Fly ash Limestone and gypsum U.S.EPA 1631 Stack emission U.S. EPA Method 29

IV. Coal sampling : Summary of coal samples Code: Plant/Source The ASTM D4596-09 procedure (Standard Practice for Collection of Channel Samples of Coal in a Mine) were modified for coal sampling in this study. Code: Plant/Source Type of coal Number of sample Plant 1 (source 1) BC: (Bee Creek), Australia HV: (Hunter Valley), Australia SU: (Suek), Russia   Bituminous 15 samples 5 Plant 2 (source 2) CS1: (Lignite mine: Spec 1), Thailand CS2: (Lignite mine: Spec 2), Thailand Lignite 10 samples

III. Coal sampling : Summary of coal samples Code: Plant/Source Type of coal Number of sample Plant 3 (source 3) JM: SM 300 (PT Jembayan muarabara), Indonesia KP: SM 301 (PT Kaltim Pruma coal) ), Indonesia KM: SM 302 (PT Khotia Makmur insan Abidi), Indonesia   Bituminous 15 samples 5 Plant 4 (source 4) BP: (Indominco), Indonesia LH: (Lanna Harita), Indonesia 10 samples Total 50

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Proximate analysis of feed coals (Unit: %) Percentage (%)

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Ultimate analysis of feed coals (Unit: %) Percentage (%)

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Chemical analysis of feed coals Unit: mg/kg Unit: g/kg ND < 1.00

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Chemical analysis of feed coals Unit: mg/kg Unit: μg/kg

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Chemical analysis of feed coals Unit: g/kg Unit: μg/kg

III. Results of Coal analysis Blue bars: Coal source 1 Red bars: Coal source 2 Green bars: Coal source 3 Yellow bars: Coal source 4 III. Results of Coal analysis : Properties of coal samples Chemical analysis of feed coals Unit: g/kg Unit: g/kg

III. Results of Mercury analysis : Mercury concentration and speciation in coal fired power plant Mercury was sampled from two power plants (four units) in Thailand and there are six types of sample to be collected at each power plant as follows: Sample types Sampling points Pulverized coal Bottom ash Fly ash Seawater Lime and Gypsum Stack gas 1 2 3 4 5 6 PC boiler ESP FGD Bottom ash Fly-ash Sea water- out/Gypsum Flue gas in stack emission Coal: Pulverized Sea water-in /Limestone

III. Results of Mercury analysis : Mercury concentration in coal fired power plant Mercury concentration Mercury concentration

III. Results of Mercury analysis : Mercury concentration in coal fired power plant Mercury concentration Mercury concentration

III. Results of Mercury analysis : Mercury concentration in coal fired power plant Mercury concentration Mercury concentration

III. Results of Mercury analysis : Mercury concentration in coal fired power plant Mercury concentration Mercury concentration

III. Results of Mercury analysis : Mercury speciation in flue gas streams Plant 1 Plant 2-Unit6

III. Results of Mercury analysis : Mercury speciation in flue gas streams Plant 2-Unit 10 Plant 2-Unit 13

III. Results of Mercury analysis : Mercury speciation in flue gas streams Summary The oxidized mercury (Hg2+) was most likely bound to gypsum slurry (140.69±8.79-168.92±38.92 μg/kg). However, Hg2+ absorbed in SWFGD was little (0.09±0.02 μg/L). The total mercury concentration in the flue gas streams (i.e., Hg0, Hg2+ and Hg(p)) is correlated to the mercury content in the coal blends. The flue gases at stack of the Plant 1 contained all three forms with a similar portion about 32-36%, whereas in the Plant 2, the flue gases contained a significant quantity of Hg0, possessing 67-81% of the total mercury.

III. Results of Mercury analysis : Mercury mass balance in coal fired power plants The overall Hg balance for each plant was around 38.6% for Plant 1, 82.2% for Plant 2/Unit 6, 109% for Plant 2/Unit 10 and 64.8% for Plant 2/Unit 13. Plant 1 Bituminous Plant 2 lignite/Unit 6

III. Results of Mercury analysis : Mercury mass balance in coal fired power plants The overall Hg balance for each plant was around 38.6% for Plant 1, 82.2% for Plant 2/Unit 6, 109% for Plant 2/Unit 10 and 64.8% for Plant 2/Unit 13. Plant 2 lignite/Unit 10 Plant 2 lignite/Unit 13

V. Future mercury emission estimation

IV. Future mercury emission estimation : Using the measured data from this study Based on the actual data collected from this study, the emission factor calculations were performed following two scenarios: (1) from the direct stack emission of mercury (actual concentrations) and (2) from the uncaptured emission Table Emission factors based on two calculation approaches Calculation scenarios Mercury emission factor (mg/ton) Range Mean±SD 1. Using the direct stack measurement Plant 1 4.50-15.36 8.59±4.86 Plant 2 22.41-109.69 69.67±30.07 2. Using uncaptured Hg estimation 29.19-55.69 44.31±11.40 68.45-103.61 85.76±9.91

IV. Future mercury emission estimation : Using the measured data from this study Scenario 1 Future mercury emission estimated from stack measurement In 2025, the predicted Hg emission is expected to decrease about 52.8% compared with those in 2017. This is because lignite consumption is projected to decline by about 62.5%, even though bituminous consumption is expected to increase about 28.6% compared with bituminous consumed in 2017.

IV. Future mercury emission estimation : Using the measured data from this study Scenario 2 Future mercury emission estimated from uncaptured mercury emission In 2025, the predicted Hg emission is expected to decrease about 27.2% compared with those in 2017. This findings were slightly different from those in scenario 1 as the EF in this scenario is higher than that in scenario 1. Mercury emission from bituminous power plant is also found to be higher than scenario 1, resulting in higher total Hg emission rate than the emission rate generated by scenario 1.

IV. Future mercury emission estimation : Using the existing Hg removal efficiency of relevant APCDs in literatures Table Reviewed mercury removal efficiency of relevant air pollution control devices Coal Type APCDs Hg removal Efficiency (%) Country Reference Bituminous PC+CS-ESP 27 China Wang et al., 2010 PC+CS-ESP+WFGD 21 PC+FF+WFGD 71 USA ICR, 2010 PC+SCR+CS-ESP+WFGD 66 Cheng et al., 2009 PC+SCR+CS-ESP+SW-FGD 29 Chen et al., 2008 Lignite 39 Table Removal efficiency of broiler Power plant Mercury removal efficiency (%) Range Mean ± SD Plant 1 0.01-0.07 0.03±0.03 Plant 2 0.04-3.96 0.86±1.10

IV. Future mercury emission estimation : Using the existing Hg removal efficiency of relevant APCDs in literatures Case 1 Future Hg emission estimated from the removal efficiency of different APCD systems, which was taken from literatures

IV. Future mercury emission estimation : Using the existing Hg removal efficiency of relevant APCDs in literatures Case 2 Future Hg emissions of 23 coal and lignite power plants and new power plants which were estimated by using the adopted Hg removal efficiency taken from literatures

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