Experience is our Technology ℠ SmartMill Technology Guaranteeing Particle Size, Quality and Production with On-site Sorbent Milling Experience is our Technology ℠ 1
STM Group STM Experience STM has over 500 systems installed worldwide, between feeders, mills and classifiers. Worldwide Presence STM has a presence on all 5 continents and in all business sectors that use mills feeders and dynamic classifiers. With the most innovative solutions in their respective class, STM is a supplier of disruptive technology. Innovative Products The performance of all STM products and systems is guaranteed, whether it be production, particle size, or efficiency. Guaranteed Performance 2
Sodium Sorbent Milling Sodium Dry Injection Technology Experience ‣ In the 90s, STM led the world in dry grinding for gas STM Serial No. 1. cleaning applications by Reggio Emilia helping a world-leading Incinerator, Italy chemical supplier develop a novel gas cleaning approach using sodium sorbents. ‣ Today, STM has more Latest STM Hammermill sorbent mill installations Design than any other mill supplier, exceeding 500 installations. 3
Na Sorbent Decomposition Behavior of Sodium Sorbents at Temperature Sodium Sorbent Decomposition � Sodium Bicarbonate 2NaHCO 3 → Na 2 CO 3 + H 2 O + CO 2 � Trona 2 [ Na 2 CO 3 • NaHCO 3 • 2H 2 O ] → 3Na 2 CO 3 + 5H 2 O + CO 2 Acid Gas Neutralization HCl Removal Na 2 CO 3 + 2HCl → 2NaCl + H 2 O + CO 2 SO 2 Removal Na 2 CO 3 + SO 2 → Na 2 SO 3 + CO 2 and Na 2 SO 3 + 1 / 2 O 2 → Na 2 SO 4 Slide Courtesy of Solvay 4
Gas Cleaning Systems Optimal System for Each Application Combustion Process Sodium Sorbent Type Sodium Bicarbonate Trona Industrial and Hazardous Waste • Incineration Biomass • Cement • Power • • Water Treatment Metals Recovery Furnace • Cremation • General Combustion: Heavy • • Fuel Oil and Natural Gas Municipal and Hospital Waste • • Incineration Steel and Foundries • • Glass • 5
Gas Cleaning Comparison Characteristics of Various Sodium Sorbents Sodium Bicarbonate Trona Stoichiometric Ratio 0.8-1.4 1.8-2.5 Gas Temperature 120-400 °C 135-800 °C Reaction Time >2 Sec >4 Sec HCl Efficiency >99% >95% SO 2 Efficiency >98% >90% SO 3 Efficiency >98% >95% 6
Na Performance curve Variations in Stoichiometry for a Given Efficiency Slide Courtesy of Solvay 7
Na Performance curve Variations in Efficiency for a Given Stoichiometry Slide Courtesy of Solvay 8
E ffi ciency Factors Some of the Factors that Affect Acid Gas Removal ‣ Both stoichiometry and e ffi ciency variations can be reduced down to one main operational parameter - Particle Size Distribution! ‣ Getting down to the correct particle size is necessary to achieve the required e ffi ciencies. ‣ Maintaining the correct particle size year- over-year is necessary to maintain e ffi ciency year-over-year. 9
Sorbent Particle Size Particle Size for SO 2 Removal 20 µm PARTICLE SIZE x 10 = 0.93µm x 50 = 5.60µm x 90 = 20.15µm x 97 = 32.29µm x 98 = 37.55µm x 99 = 48.14µm 10
Sorbent Particle Size Particle Size for HCl Removal 30 µm PARTICLE SIZE x 10 = 1.87µm x 50 = 14.64µm x 90 = 33.88µm x 97 = 44.47µm x 98 = 48.19µm x 99 = 53.62µm 11
Na Calcining Calcination occurs at elevated temperatures 12
Sorbent Injection Flowsheet for PC-fired Boiler with Duct Injection 13
Sorbent Injection Flowsheet for PC-fired Boiler with Reactor 14
Sorbent Injection Typical Reactor Designs Single Pass Reactor Double Pass Reactor 15
CFD Optimization Need for Distribution Analysis Single Pass Reactor Double Pass Reactor 16
E ffi ciency Factors Some of the Factors that Affect Acid Gas Removal ‣ Gas Flow Factors Temperature • Mixing (turbulence) • Distribution • ‣ Sorbent Factors Particle Size • Purity • Material Integrity • 17
Milled Sorbent Challenges On-site Particle Size Reduction vs. Pre-milled ‣ Pre-milled Storage silo release • Materials handling and transport • Particle size (clumping) • ‣ On-site Milling Maintenance • Particle size consistency • Operational issues (difficult to keep clean) • 18
Basic Mill Technology What mills are being used? ‣ Pin Mill Uses pins rotating on rotors • ‣ Screen Mill Uses hammers rotating against a screen • ‣ Hammer Mill Uses hammers rotating against a track • 19
Basic Mill Comparison Mills that should not be used and why ‣ Pin Mill: Prone to build-up • Difficult to clean pins online • Requires frequent and long interventions • No classifier to separate fine particles • ‣ Screen Mill: Prone to build-up • Difficult to clean online • Requires frequent cleanings • No classifier to separate fine particles • 20
Basic Mill Comparison Mills that could be used and why ‣ Compact Hammer Mill: Easy to keep clean with glycol addition • Requires little maintenance • Built-in propulsion fan - negative pressure • Self classifier to separate fine particles • ‣ Twin Rotor Hammer Mill: Not as prone to build-up • Easy to clean and maintain • Twin rotors for higher production • Separate dynamic classifier • 21
Compact Mill Self-classifying, compact design ‣ Flow-through, self-classifying mill coupled to a transport air fan. The self-classifying design makes it a good choice for applications where narrow particle size distribution is not critical. ‣ Ideal for low-cost retrofit applications. ‣ Operational advantages: Low energy consumption ‣ Minimal maintenance needs ‣ Compact, small space requirement ‣ Ease of installation ‣ Automatic operation ‣ 22
Compact Mill Limitations Design limitations of a compact hammer mill ‣ Limited size single rotor Limits production rate • Requires higher velocity • Typically used in smaller • installations ‣ In-line classifier Imperfect control over particle • size distribution D 50 particle size ±10-15 µm • D 90 particle size ±35-40 µm • 23
Basic Twin Hammer Mill Air classifying, twin rotor design ‣ Twin rotor, air-classifying mill with a separate transport air fan. The twin rotor design makes it a good choice for applications where mill temperature and particle integrity is not critical, such as calcium-based materials. ‣ Ideal for medium/large gas cleaning plants and for low-cost retrofit applications. ‣ Operational advantages: Low energy consumption ‣ Minimal maintenance needs ‣ Compact, small space requirement ‣ Basic Hammer Mill Ease of installation ‣ Automatic operation ‣ 24
Hammer Mill Limitations Mills that could be used and why ‣ Older generation mill ‣ Medium size twin rotors Limits production rate • Requires higher rotor velocities • ‣ Dynamic classifier Better control over particle size • distribution D 97 particle size ±15-20 µm • ‣ Significant heat build-up Like all ACMs, heat build-up makes • it less desirable for milling sodium 25
Other Hammermills Competitive Mill - Positive Pressure and Excess Heat ‣ Older generation mill ‣ Shroud ba ffl e assembly Requires that first pass milled material flow around it • Designed to create circuit for rejects to return to mill hammers • Turbulence around shroud baffle plate causes excess heat • ‣ Dynamic classifier Good control over particle size distribution • D 97 particle size ±15-20 µm • ‣ Significant material build-up Heat causes build-up making it less desirable for milling sodium • 26
Other Hammermills Competitive Mill - Positive Pressure Operation 27
Basic Milling Technology Controller Booster Feeder Fan Sorbent Injection + + + + + Fan/blower Chiller Mill Classifier Traditional Sorbent Milling System Arrangement Traditional milling systems are made up of several components, each engineered, purchased, installed, wired and controlled separately. Until recently, there was no option that provided a single, integrated milling solution. 28
Sorbent Mill Elements Feeder - Required for metering the needed amount of sorbent into the mill Mill - Finely grinds the sorbent to improve the efficiency of the scrubbing Classifier - Allows fine sorbent through and returns the large material to the mill Fan/blower - Blows fine sorbent to the injection lances Chiller - Cools the incoming air to prevent sorbent from reacting in the mill Booster Fan - Boosts the pressure of the sorbent transport air Controller - Regulates each element of the milling circuit 29
Traditional Milling Systems Feeder - $40,000 Cost of a Traditional Sorbent Milling System Mill - $90,000 Cost of components-only Classifier - $20,000 1000 kg/h sorbent milling system: Fan/blower - $15,000 $240,000 Chiller - $15,000 and that does not include installation, wiring, Booster Fan - $10,000 engineering nor 8400 hour guarantee! Controller - $50,000 30
Bicarmill Smart Mill - Bicarmill ™ - The Complete Package Housing all of the necessary components into a single, pre-engineered compact system, the Bicarmill is the guaranteed solution to on-site milling of sodium sorbent, all at a price that is much lower than the combined components of any mill on the market today. Total cost of a complete 1000 kg/h Bicarmill system: $189,000 including an 8400 hour continuous operation guarantee! 31
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