Pollution Engineering - November 2008 - (Page 55)

Advertorial HOWTO: Apply an Alternative to Wet ESP By TRI-MER CORP . AIR POLLUTION CONTROL C loud Chamber Scrubber (CCS) technology is sometimes confused with electrostatic precipitation (ESP) because both use electric charge. Aside from this superficial similarity, the technologies are strikingly different. Only the CCS uses charged droplets. Wet ESP works by charging the particles in a gas stream, causing them to migrate through an electrostatic gradient Wet ESP: Charging Particles • Charges each sub-micron particle with a charge of a few dozen electrons • Long particle drift distance, several centimeters average to collection plates • Charging: 1000-3000 watts per 1000 cfm. Voltage is 50kV - 100 kV. Sparking and current suppression. Corona charging of particles is difficult. • Low pressure drop, less than 1.0” w.g., higher if combined with gas scrubber • Recirculation pumping less than CCS but charging power dramatically higher • Total system energy usage much higher compared to the CCS • Ultra-low water usage to remove pollutants from the W-ESP system • Light loading only, relatively sensitive to changes in loading • Poor turn-down for process air flow changes or real-time variations • Corrosion by acids accelerated by high electrical currents, thin water films leave dry spots and build-up • High maintenance – dozens of tubes to cake and complicated electrical system, downtime CCS: Charging Water Droplets • Charges each sub-millimeter droplet with a charge of millions of positive or negative charges • Short particle drift distance, approximately 20 microns average before capture by droplets • Charging: 10 watts per 1000 cfm. Voltage is 10kv - 15kV. No corona charging. Water readily accepts a high charge using patented method. • Low pressure drop, less than 1.2” w.g. including gas scrubber. • Recirculation pumping more than W-ESP but charging power a small fraction • Total system energy usage much lower compared to the W-ESP • Ultra-low water usage to remove pollutants from the CCS system • Heavy or light loading, relatively insensitive to changes in loading • Excellent turn-down for process air flow changes and real-time variations • Corrosion virtually non-existent, no high currents, cascade washed surfaces, build-up eliminated • Low maintenance - simple open vessel design, routine preventative inspection, uptime Illustration details at tri-mer.com/wet_scrubber.html particle applications. Utilizing wet ESP might be possible, though often requiring multiple stages. Typically, only light pollutant loading is practical; even so, satisfactory removal is not possible on many pollutants. handle even heavy particle loading with high efficiency. The CCS does not have the very high voltage plus high amp draw demanded by corona charging, or the associated arcing, sparking, and current suppression (space charge) limitations. to metal collectors where they are washed into a sump. The particles have to “drift” a considerable distance to the metal collecting plates. Many conditions can prevent successful collection. In general, dry ESP is not suitable for submicron CCS in Contrast with Wet ESP In contrast, CCS technology removes submicron particles simply and effectively. The CCS charges only the collector (that is, the water droplets) and mingles the charged collector droplets with the particles. When a particle passes within 20 microns, the droplet charge induces a dipole force on the particle, which causes the particle to move the short distance to the droplet for capture and collection. The charged droplet “cloud” is able to Additional Advantages of the CCS Compared to W-ESP • Much lower power consumption • Removes coarse, fine, submicron, ultrafine, and condensable particulate • Greater flexibility – particles larger than a few microns can interfere with functionality of W-ESP • Simultaneously removes acid gases with efficiencies equal to a packed bed scrubber ® CORPORATION Tri-Mer ® (989) 723-7838 • (989) 723-7844 • kevin.moss@tri-mer.com www.tri-mer.com HOWTO GUIDE | NOVEMBER2008 www.pollutionengineering.com 55 http://tri-mer.com/wet_scrubber.html http://www.tri-mer.com http://www.pollutionengineering.com

Table of Contents Feed for the Digital Edition of Pollution Engineering - November 2008

Pollution Engineering - November 2008 Contents The Editor's Desk EnviroNews PE Events Legal Lookout Casebook Canada Environment Management The Green Files Waste Island Phase I ESAs and Vapor Intrusion Meeting the Mercury Target Wet ESPs - The Sky's the Limit Most Successful IFAT China Ever Thermoplastic to the Rescue Install a Trench Without Open Excavations Remediate Impacted Soils Without Accumulation of Metabolites Apply an Alternative to Wet ESP Solve These Common Pump Problems Minimize Risks Handling Ammonia Monitor International Regulatory Developments for Audits Skim Oil and Save Prevent Chemical Vapor Intrusion Spill Control and Containment Products Pumps and Systems Equipment PE Products Classified Marketplace Advertisers Index State Rules

Pollution Engineering - November 2008

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