Chapter 13 Introduction to Control Technology Introduction to Control Technology Carbon adsorption Incineration Condensation Bioreaction Carbon Adsorption 13-1
Activated Carbon A class of materials Produced from coal, wood, nut shells and petroleum-based products Activation process Heat material to ~1,100 F without oxygen Use stream, air or CO 2 to increase pore structure Types of Adsorption Processes Chemical adsorption Physical adsorption 13-2
Retention Adsorption Capacity Lbs of VOC adsorbed per 100 lbs of carbon Weight percent 13-3
13-4
Types of Adsorption Systems On-site regeneration Off-site regeneration 13-5
OffOff-Site Regeneration Adsorbers Activated carbon Pleated thin bed Canister Canister Adsorber Activated carbon Support material On On--Site Regeneration FixedFixed-Bed System Steam Pretreatment Condenser Outlet Regenerating steam 13-6
Regeneration Methods Thermal swing Steam Hot gas Pressure swing Steam Regeneration Bed 1 Steam and solvent vapor to condenser Solvent laden air Fan Particulate matter filter Heat exchanger Steam Bed 2 Air to stack Steam and solvent vapor to condenser Steam and solvent vapor Condenser Cold water Particulate Decanter Water Cold water Storage tank Recovered solvent Steam Steam Bed 3 Air to stack Steam and solvent vapor to condenser Air to stack 13-7
Regeneration Methods Thermal swing Steam Hot gas Pressure swing Regeneration Methods Thermal swing Steam Hot gas Pressure swing Other Adsorber Designs 13-8
Carbon Fiber Adsorber Purified Exhaust Air Steam solvent mixture Cooling water Condenser Fan Control panel Pre-filter Cooling water Solvent-laden exhaust air Steam Waste water Separator Recovered solvent Rotary Bed Adsorber Clean air out Perforated trays Fluidized Bed Adsorber Solvent-laden air Secondary adsorber Desorber heating section Nitrogen recycle blower Cooling section Out In Air lift blower Recovered solvent 13-9
Incineration Flares Thermal oxidizers Catalytic oxidizers Flare Waste gas retention ring Steam injection point Pilot assembly Steam distribution ring Flare stack Thermal Oxidizer Refractory Refractory--brink lined chamber with one or more oil or gas burners Temperature: 1,300 1,300--1,800 1,800 F Residence time: 0.30.3-0.5 seconds 13-10
Recuperative Thermal Oxidizer Regenerative Thermal Oxidizer Induced draft fan Ceramic media Valves Process Heaters and Boilers Boiler must operate at 4040-100% of full load Contaminated gas stream flow rate should be small portion of total Nothing corrosive or that causes deposits 13-11
Catalytic Oxidizer Catalyst Materials Noble metal oxides Platinum Palladium Rhodium Base metal oxides Vanadium Titanium Manganese 13-12
Temperature ~100 ~100 F above catalyst lightlight-off temperature Typical inlet temperature: 500500-600 600 F Typical outlet temperature: 700700-900 900 F Maximum outlet temperature: 1,1001,100-1,200 1,200 F Space Velocity Space Velocity Q BV Q = standard flow rate (60 F) BV = catalyst bed volume Typically 30,000-40,000 hr-1 for noble metals 10,000-15,000 hr-1 for base metals 13-13
Catalyst Performance Problems Fouling Poisoning Masking Thermal aging Condensation Conventional systems Refrigeration systems Cryogenic systems Types of Condensers Direct contact condensers Surface condensers 13-14
Mist eliminator Spray nozzles Direct Contact Condenser Ejector Condenser Inlet gas stream High pressure spray nozzle Discharge Shell and Tube Condenser Coolant inlet Coolant outlet Noncondensing vapor outlet Straight seamless tubes Baffles Reversing channel Condensate outlet 13-15
Tube and Fin Condenser Traverse fins Longitudinal fins Refrigeration Cycle Refrigeration unit Refrigerant condenser Expansion valve Air Fan Refrigerant liquid Contact chamber Refrigerant compressor Refrigerant vapor Refrigerant evaporator Solvent laden air Exhaust gas Condensate Refrigeration System Refrigeration unit 1 Refrigerant 1 Solvent laden air Fan Refrigeration unit 2 Refrigerant 2 Pre-condenser Main chamber Water condensate Exhaust Organic condensate 13-16
Single Heat Exchanger Cryogenic System Gaseous N2 to atmosphere Exhaust to atmosphere Liquid N2 storage Heat exchanger Solvent laden air Control valve for liquid N2 Condensate Dual Heat Exchanger Cryogenic System Gaseous N2 to atmosphere Recirculated heat exchange fluid Exhaust to atmosphere Heat exchanger 1 Liquid N2 storage Heat exchanger 2 Solvent laden air Control valve for liquid N2 Pump feed tank Pump Condensate Bioreaction Biofilters Biotrickling filters Bioscrubbers 13-17
Microbial Population Requirements Sufficient moisture Sufficient nutrients Temperature of 60 60 F to 85 85 F ph of 6 to 8 Biofilter System Discontinuous water addition Nutrients, buffer (Discontinuous) Waste air Water influent Biofilter reactor Waste air Particulate, temperature, and load control Clean air Blower Humidifier Leachate Biotrickling Filter System Waste air Water, nutrients, buffer Water influent Waste air Particulate, temperature, and load control Biotrickling filter reactor Pump Clean air Blower Recycled water Wastewater purge 13-18
Bioscrubber System Clean air Recycled water Pump Aeration Mixer Waste air Particulate, temperature, and load control Water, nutrients, buffer Blower Purge Scrubber Reactor 13-19