Building Capacities for the Improvement of the Air Quality SOx - Abatement Lima, 24.06.2016 Dr. Hubert Baier General Manager - Europe
Basics on Formation of sulphur oxide S(s) + O 2 (g) -> SO 2 (g); H = -296.7 kj/mole (32kg) + (2*16kg) -> (64kg resp. 22.41m 3 ) 2 SO 2 (g) + O 2 (g) -> 2 SO 3 (g); ΔH = -198.2 kj/ mol The formation of sulphur oxide is an exothermic reaction and the product will emitted as SO 2 and SO 3. 2
Source Fossile fuels, mostly coal and oil, contain varying amounts of sulphur according to the source but typically between 1% and 5%. In developed countries, much of the sulphur is removed by refining processes prior to emission. Unfortunately, in a lot of countries unabated burning of coal and the use of crude oil and automotive diesel with higher sulphur content is still the major source of sulphur dioxide. 3
SOx-emission 2013 in kt German Trend and Sectors of SOx emission 250 225.61 200 150 100 50 60.97 34.89 34.68 31.29 18.14 0 4.83 2.03 1.25 1.23 0.87 0.20 0.12 0.05 4
kt German Trend and Sectors of SOx emission 6000 1990 2014 total emission of SO 2 5000 4000 3000 2000 1000 0 5
The policy of the high stacks is finally ending Power Plant of Boxberg 2009/ Paul Toto (Bautzen Oberlausitz) 6
Steps of SOx-Mitigation 1) Sulfide reduction 7
Pyrite/ Markasite the natural sources of sulphur When pyrite is tangly incorporated in the coal, it has to be processed by cleaning procedures before utilization Credits: Multotec 8
Steps of SOx-Mitigation 1) Sulfide reduction 2) Prefered tax for sulphur-poor fuels/ penalize sulphur-rich fuels 9
Composition of main fuels In the European Union all available types of fuels are used. Each nation focusses on its own local country wide access. Median composition of fuels (ash free): Mass-% C H N O S Lignite 58-75 0-7 0.4 1 15 35 0.8 2.5 Hardcoal 81 92 4-7 1.5 2-10 1-2 Oil S 86-89 10-12 0.005-1 0-50 0.01 2 (4.5) Petrol 85 15 < 0.004 Wood 47-53 5 7 0.1 1 42 46 0.01 0.3 Gas (CH 4 ) 93 1 14 Biogas (CH 4 ) 50 60 10
Steps of SOx-Mitigation 1) Sulfide reduction 2) Prefered tax for sulphur-poor fuels/ penalize sulphur-rich fuels 3) Set pollution control measurements 11
Basics on formation of sulphur oxide The formation of pollutants in a combustion process is unavoidable but in practice it can be reduced by 1) optimization of the combustion process (primary measures) or 2) exhaust gas cleaning (secondary measures) 3) use best available technic 12
BAT measures for specific fuels Fuel Combi process Thermal efficiency (% net) Hard coal and lignite Hard coal lignite Biomass CHP Dry furnace/ wet bottom firing New Existing 75 90 75 90 43 47 FBC >41-42 Dry firing/ wet bottom firing 42 45 FBC >40 42 Stoker fired (CHP) 75 90 FBC >28 30 36-40 Gas Motor or turbine 36-45 32 - >35 13
Values of the German Pollution Control Act Parameter Dimension Incineration and Co- Incineration Half-hourly average Daily average Annual average Total Dust mg/nm 3 30 20 10 gaseous Chlorine and its components, quoted as HCl gaseous Fluorine and its components, quoted as HF mg/nm 3 60 10 mg/nm 3 4 1 SO x, quoted as SO 2 mg/nm 3 200 50 Organic components, quoted as C total mg/nm 3 20 10 Carbon monoxide mg/nm 3 100 200 NO x, quoted as NO 2 Waste incinerator power plant >100MW Cement kiln mg/nm 3 100 100 200 100 800 1) / 400 500 1) /200 1) Clause for transitional period for old kilns
Values of the German Pollution Control Act Parameter Dimension Incineration and Co- Incineration Mercury and its components, quoted as Hg Cadmium and Thallium and their components, quoted as Cd, Th Antimony, Arsenic, Lead, Chromium, Cobalt, Copper, Manganese, Nickel, Vanadium, Tin and their components, quoted as Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V, Sn Half-hourly average Daily average mg/nm 3 0,05 0,05 Annual average mg/nm 3 0,05 mg/nm 3 0,5 Benz(a)pyren mg/nm 3 0,05 PCDD/ PCDF ng TE/ m 3 0,1
State of the art: Power Plants 16
Chemistry of gas cleaning Milk of lime or lime stone will be mixed, sprayed and react as followed: 1)SOx + H 2 O H 2 SO 3 2)H 2 SO 3 + CaCO 3 + H 2 O CaSO 3 * ½ H 2 O + xh 2 O + CO 2 3)H 2 SO 3 + Ca(OH) 2 CaSO 3 * ½ H 2 O + xh 2 O 4)H 2 SO 3 + ½ O 2 H 2 SO 4 5)H 2 SO 4 + CaCO 3 + H 2 O CaSO 4 *2H 2 O + CO 2 6)H 2 SO 4 + Ca(OH) 2 CaSO 4 *2H 2 O There are several technical solutions availbale for power plants. 17
Wet scrubber Chemistry of SOx gas cleaning process medium absorbent product usage advantage dry scrubber lime wash ammonia wash spray absorption flue gas flue gas flue gas flue gas lime CaCO 3 ammonia active charcoal hydrated lime Sulphate sludge ammonia sulphate SO 2 sulphide/fly ash mixture FGD gypsum fertilizer (sulphuric acid, elementary S) landfill (monolith) disadvantage costs waste water costs no waste water less waste water less costs no waste water drying/ heating fertilizer market (unstable) technical problems (aerosol) "chemical plant costs land consumption groundwater protection 18
SOx-Cleaning Process Process scheme of a dry scrubbing process 19
Chemistry of gas cleaning Dry scrubbing process: 1) SOx + Humidity (H 2 O) H 2 SO 3 (sulphonic acid) It will be neutralized by lime or lime stone: 2a) H 2 SO 3 + CaCO 3 CaSO 3 + H 2 O + CO 2 2b) H 2 SO 3 + Ca(OH) 2 CaSO 3 + 2H 2 O 3) 2CaSO 3 + H 2 O CaSO 3 * ½ H 2 O This residue retardes the cement reaction! 20
Sorption is a physical and chemical process by which one substance becomes attached 21
Chemistry of gas cleaning Wet scrubbing process: 1) SOx + H 2 O + ½ O 2 H 2 SO 4 (sulphuric acid) It will be neutralized by lime or lime stone: 2a) H 2 SO 4 + CaCO 3 + H 2 O CaSO 4 *2H 2 O + CO 2 2b) H 2 SO 4 + Ca(OH) 2 + H 2 O CaSO 4 *2H 2 O This residue is called FGD-gypsum and takes its predictable part in the cement reaction. 22
SOx-Cleaning Process Wet flue gas desulphurization (FGD) process Credits: AE&E 23
Flue-Gas-Desulphurization Gypsum In Germany the annual amount of FGD gypsum from lignite fired and hard coal fired power plants is ~4.5 mio tpy, which substitutes natural gypsum in the plaster board industry and cement industry. Credits: RWE/ Knauf/ RWTH Aachen 24
Rough calculation on FGD output CaO + SO 2 +0,5 O 2 +2H 2 O CaSO 4 *2H 2 O mol-wt: 57,08 66,06 17,00 38,030 178,172 32,0% 37,1% 9,5% 21,3% 100,0% emission: 2.000 ppm/nm 3 Limited set point 50 ppm/nm 3 reduction: 1.950 ppm/nm 3 SO 2 = SO 2 : 1,950 g/nm 3 demand on CaO: 1,685 g/nm 3 demand on O 2 : 0,502 g/nm 3 demand on H 2 O: 1,123 g/nm 3 resulting gypsum: 5,259 g/nm 3 (per annum: ~60.000 t) 25
Comparison of natural and FGD gypsum Heavy metal natural gypsum FGD-gypsum max. mg/kg max. mg/kg arsenic 4 3 beryllium 0,7 0,6 lead 21 22 cadmium 0,5 0,3 chromium 25 10 cobalt 4 2 copper 14 9 manganese 130 200 nickelum 13 13 mercury 0,09 1,3 selenium 0,5 16 tellurium 0,2 0,3 thallium 0,2 0,4 vanadin 26 8 zinc 40 50 26
State of the art: Cement Production 1 2 4 5 3 1. Preparation of raw materials into raw meal: Extraction Crushing [1] Pre-homogenisation [2] - Dosing Grinding Homogenisation [3] 2. Clinker production: pyro-processing of raw materials - calcination of the raw meal in the rotary kiln [4] energy supplied by burning fuels 3. Cement production: grinding of clinker and mineral components to obtain cement quality regarding demand and cement standard [5]
Key of SO 2 Emission Pyritic Sulphur S 2- Sulphur is volatile (T 400 500 C) e.g. 2 FeS 2 + 5,5 O 2 Fe 2 O 3 + 4 SO 2 Main reason for SO 2 emission Fuel- and low volatility Sulphur: Almost perfect absorption (>99%) (CaO + T > 600 C) CaO + SO 2 + 0,5 O 2 CaSO 4 Air excess required! 28 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
Way of (Pyritic) Sulphur in Direct Operation Expulsion of S 2 - in the preheater Small slip of Fuel SO 2 possible Direct operation Raw Meal Silo SO 2 Low adsorption on dust Higher emission level S 2 - + 2 O 2 2 SO 2 SO 2 Dust SO 2 + O 2 SO 3 SO 2 SO 3 H 2 O Silo Clinker 29 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
Way of (Pyritic) Sulphur in compound Operation Expulsion of S 2 - in the preheater Small slip of Fuel SO 2 possible Compound operation: Adsorption in the raw mill Lower emission level Raw Meal Silo Raw Mix SO 2 SO 2 Mill bypass increase emission level S 2 - + 2 O 2 2 SO 2 SO 2 + O 2 SO 3 SO 2 SO 3 Silo Dust Clinker 30 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
Way of (Pyritic) Sulphur in Direct Operation Expulsion of S 2 - in the preheater Small slip of Fuel SO 2 possible Direct operation Raw Meal Silo SO 2 Low adsorption on dust Higher emission level S 2 - + 2 O 2 2 SO 2 SO 2 Dust SO 2 + O 2 SO 3 SO 2 SO 3 H 2 O Silo Clinker 31 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
Way of (Pyritic) Sulphur in compound Operation Expulsion of S 2 - in the preheater Small slip of Fuel SO 2 possible Compound operation: Adsorption in the raw mill Lower emission level Raw Meal Silo Raw Mix SO 2 SO 2 Mill bypass increase emission level S 2 - + 2 O 2 2 SO 2 SO 2 + O 2 SO 3 SO 2 SO 3 Silo Dust Clinker 32 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
SO 2 sorption raw mill total emission Depends on the specific Sulphur load in the mill 30-90% raw mill 40-80% preheater 100% S 2- derived SO 2 Diss. Seidler 33 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
SO 2 Abatement Ca based Scrubbing Systems H 2 O Dry Scrubbing Ca(OH) 2 CaSO 3 / CaSO 4 H 2 O Semi Dry Scrubbing Ca(OH) 2 CaSO 4 Ca(OH) 2 CaSO 3 / CaSO 4 H 2 O Ca(OH) 2 Wet Scrubbing CaSO 4 Silo Suitable System or a combination of systems depends on raw gas emission and clean gas emission to be achieved 34 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
SO 2 Abatement Always to be considered as the first approach for SO 2 -abatement 35 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
SO 2 -Scrubbing Systems: NaHCO 3 as an alternative to Ca(OH) 2 H 2 O NaHCO 3 x Ca(OH) 2 CaSO 3 / CaSO 4 Na 2 SO 3 / Na 2 SO 4 Ca(OH) 2 NaHCO 3 CaSO 3 / CaSO 4 (50 / 50) Na 2 SO 3 / Na 2 SO 4 (33 / 67) < 100 150 C 150 300 C (Activation) High moisture HCl presence advantageous Independent of moisture HCl independent Ca : SO 2 2 Na 2 : SO 2 1,2 (Na : SO 2 2,4) 3 kg Ca(OH) 2 /kg SO 2 2 kg NaHCO 3 /kg SO 2 Adsorption Waste agent Arising $$ $$$$ 36 June 15th, 2016 SO2-Emission and Abatement R. Beilmann
Used tires the additional source of sulphur Mass- % C H N O S Lignite 58-75 0-7 0.4 1 15 35 0.8 2.5 Hard coal 81 92 4-7 1.5 2-10 1-2 Oil S 86 89 10-12 0.005-1 0-50 0.01 2 (4.5) Used tires 70-75 6-7 0.5 4 1 1.7 But when tires are fed they will play a bigger role due to 37
SO 2 reaction processes Process SO 2 Formation SO 2 Absorption Raw mill Sulfides + O 2 Oxides + SO 2 Organic S + O 2 SO 2 CaCO 3 + SO 2 CaSO 3 + CO 2 Preheating zone Sulfides + O 2 Oxides + SO 2 Organic S + O 2 SO 2 CaCO 3 + SO 2 CaSO 3 + CO 2 Calcining zone Fuel S + O 2 SO 2 CaSO 4 + C CaO + SO 2 + CO CaO + SO 2 CaSO 3 CaSO 3 + ½ O 2 CaSO 4 Burning zone Fuel S + O 2 SO 2 Sulfates Oxides + SO 2 + ½ O 2 NaO + SO 2 + ½ O 2 NaSO 4 K 2 O + SO 2 + ½ O 2 K 2 SO 4 CaO + SO 2 + ½ O 2 CaSO 4 38
Volatile and soluble compounds in clinker Chlorides NaCl 801 C KCl 776 C CaCl 2 772 C Sulphates Na 2 SO 4 884 C K 2 SO 4 1.069 C CaSO 4 decomposes at 1.280 C 39
Volatile and soluble compounds in clinker evapuration/ condensation K 2 SO 4 K 3 Na(SO 4 ) 2 Na 2 SO 4 Ca 2 K 2 (SO 4 ) 3 soluble/ discharge K with Belite and Aluminate Na with Aluminate SO 3 with Belite Alkali-Sulphate-Ratio (ASR) Modulus is calculated as = (K 2 O/94 + Na 2 O/62 Cl/71)/(SO 3 /81) 40
State of the art: Oil fired Power Plants Credits: Albert Bridge/ Ballylumford power station, Islandmagee (IRL) 41
Desulphurization of Hydrocarbons Mass-% C H N O S Oil S 86-89 10-12 0.005-1 0-50 0.01 2 (4.5) Petrol 85 15 < 0.004 42
State of the art: Marine Scrubber System Available are: Open loop system Closed loop Hybrid systems 43
Sulphur Emission Control Areas (SECA) The mass-% of sulphur for marine used fuels could not exceed a value of 1.5% since May, 2006. Alternatively, scrubbers can be installed to clean exhaust gas for reduction of sulphur oxide emissions. Since its enforcement date, in all SECA only marine diesels with a sulphur mass fraction of < 0,1% are permitted. Valid Location Enforcement Baltic Sea 01/ 2006 North Sea 01/ 2015 Rest of EU waters 01/ 2020 North America 01/ 2015 Hong Kong 06/ 2015 China (selected ports) 01/ 2017 44
Steps of SOx-Mitigation 1) Sulfide reduction 2) Prefered tax for sulphur-poor fuels/ penalize sulphur-rich fuels 3) Set pollution control measurements 4) Considering a SO 2 -trading system 45
SO 2 Allowance Trading The most ambitious application in US for environmental protection has been established at the EPA for the control of sulfur dioxide (SO 2 ) emissions in the context of acid rain reduction under Title IV of the Clean Air Act amendments of 1990. This Act established an allowance trading program to cut SO 2 emissions by 10 million tons from 1980 levels a 50% reduction. The SO 2 allowance trading program is still performing. 46
SO 2 Allowance Trading Conclusion: Given that the SO 2 allowancetrading program became fully binding, the market-based instrument for tradable permits enjoy proven successes in reducing pollution at low cost. Market-based instruments have moved from "licenses to pollute" to an effective policy instrument, in the US for the appropriate SO 2 problem. In the EU this issue has also been discussed, but is not implemented yet due to the different wide base line levels. 47
In a nutshell The target to reduce SOx emissions can be achieved by several mechanisms, even in parallel: Identification of the cause of emission Technical assessment/ solution Identification of the chemical composition of the fuel fault rectification (i.e. pyrite in coal or proteins in crude oil) Fiscal insentives Air pollution control (stipulated limits, measurements and consequences) Allowance trading system optional: create a System-4-Recycling 48