Landfill & Digester Gas Dryers. Features and Benefits

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2 Landfill & Digester Gas Dryers Landfill gas is generated by the anaerobic decomposition of organic matter deposited in landfills. Digester gas is produced as a by-product of the digestion of sewage sludge. The effluent gas consists mostly of methane and carbon dioxide together with water vapor and minor quantities of organic compounds. The Airtek Energy Services (AES) Landfill/Digester Gas Dryers remove moisture and impurities so the gas can be utilized as fuel source for industrial heating, power generation or steam production. Whatever your landfill/digester gas volume may be, AES can custom build a dryer to your specifications. Features and Benefits Patented Smart Cycle control reduces energy consumption and maintains a constant dew point by loading and unloading or by turning refrigeration compressor on or off in direct response to the actual dew point temperature of the gas. Patented dew point sensor precisely monitors the temperature of the gas. The gas temperature is prominently displayed on the control panel. Patented Flood Level Control increases dryer efficiency and protects refrigerant compressor from floodback. Fully active flooded shell efficiency, can act as a ballast which can sustain temporary overloads or spikes. Non-fouling heat exchangers are standard with stainless steel tubes Modular construction for easy servicing. Tube sheets have precision milled grooves for leak proof joints and greater mechanical strength. Stainless steel moisture separator with stainless steel Mist Eliminator pad, 99.9% 5 micron and larger. Diagnostic display panel includes: Shutdowns with common alarm and dry contact for high dew point, low refrigerant, and refrigeration system interruption. Electronic Demand Drain does not expel gas to atmosphere. A drain alarm warns of any malfunction. NEMA 4 is standard, optional Z purge, NEMA 7 and 9 class wiring available. Isolation valves in refrigerant circuit allows service to any part of the system without having to reclaim the entire charge, minimizing service and downtime.

3 Smart Cycle Demand Control AES s patented Smart Cycle demand control reduces energy consumption and maintains a true and constant dew point by loading and unloading or by turing the refrigeration compressor on or off in direct response to the actual dew point temperature of the gas. The Smart Cycle control automatically adjusts for constantly changing operating and inlet conditions. Direct dew point sensing and control assures the lowest possible dew point, driest gas, and significant energy savings. The Smart Cycle employs a patented, quick acting temperature sensor to precisely monitor the temperature of the landfill/digester gas at the evaporator discharge and either adjusts the load/ unload cycle accordingly or turns the refrigeration compressor on or off when in the Thermal Bank Mode.Whether the refrigeration compressor is loaded, unloaded, on or off, is determined directly by the rising and falling dew point temperature of the gas.the dew point ranges from low setting of +35 O F to the upper set point point of +39 O F (set points are adjustable). 100% Power 50% Power Smart Cycle Energy Savings When the refrigeration compressor is completely unloaded, about 50% of full load power is used. When the compressor cycles in the Standby/Off position, no energy is being consumed. 0% Power 0% Load 50% Load 100% Load ENERGY USE COMPARISON

4 Heat Exchangers The Landfill/Digester Gas Series Dryers use high efficiency, non-fouling, tube and shell heat exchangers. They are simple, reliable, and time proven. AES directs the flow of raw gas through straight, smooth bore, 304 stainless steel tubes that are surrounded by cold gas in the pre-cooler/ re-heater and colder liquid refrigerant in the main evaporator.this envelope of cold allows the Landfill/Digester Dryers to achieve and maintain optimum performance and dew point within minutes of start up. The fully active, flooded evaporator eliminates evaporator hot spots and assures a consistent dew point at all load conditions. Because tubes have no extended surfaces, bends or curves to trap and collect sediment, energy consuming flow restrictions are eliminated.the heat exchangers do not foul and pressure differential is kept to a minimum. Due to the limited number of mechanical connections and clear flow path, AES heat exchangers require little, if any, maintenance. Most other types of dryers direct the flow of dirty air through the shell of the heat exchanger where the dirt and oil collect on the tubes and surfaces. Since these heat exchangers are not cleanable, efficiency is lowered and energy consuming pressure drop increases as soon as it is put into service. Grooved Tube Sheets An Airtek Exclusive Each Tube Sheet Hole Has Precision Milled Grooves Leak-proof Joints Greater Mechanical Strength

5 Patented Flood Level Control Improves performance by doubling the effective surface area of the main evaporator. Protects the compressor from refrigerant floodback, which is a major cause of compressor failure on competitors dryers. Ensures proper oil return to the compressor, eliminating a major cause of compressor failure on competitors dryers. Eliminates the need to attempt precision adjustments on the thermostatic expansion valve. Cool Dry Gas and Oil To refrigeration compressor inlet Cold Gas / Liquid Refrigerant and Oil Mix Boiling Over From Evaporator Hot Gas From Compressor Hot Gas Out To Condenser Electronic Demand Drain AES Landfill/Digester Gas Dryers are equipped with a factory installed Zero Gas Loss electronic drain, assuring unattended, maximum reliability demand draining with absolutely no gas loss. A large orifice solenoid valve is automatically opened by a level switch assuring complete drainage. The Electronic Demand Drain eliminates fouling, pressure loss and manual adjustments associated with timed drains. Failure alarm with remote contacts are standard.

6 Flow Schematic

7 Landfill / Digester Gas Circuit Saturated gas enters the tubes of the gas to gas Heat Exchanger 1 where it is pre-cooled by the cold gas returning through the shell from the evaporator. Pre-cooling saves energy by reducing the heat load on the refrigeration system. After the gas has been pre-cooled, it flows into the evaporator tubes 2 where the temperature is lowered to approximately +34 O F.The temperature reduction forces water and oil vapor to condense. The mixture of cold landfill/digester gas and condensed liquid flows into the mechanical moisture separator 3 with Mist Eliminator Element where the liquids are removed by impingement and centrifugal action. The purified gas returns through the shell side of the gas to gas heat exchanger 4 where its volume is increased through reheating. The processed landfill/digester gas enters the main distribution system 5 as a dry, clean and efficient utility. Patented Refrigeration Circuit AES s patented refrigeration system enables the use of a fully active flooded evaporator 2. Landfill/Digester gas flows through the submerged tubes in the flooded shell to ensure dew point integrity. This is made possible because the refrigerant gas returning to the compressor must pass through the patented Flood Level Control heat exchanger 6. If any liquid refrigerant were present in the suction line, it would flash off to a vapor by the heat of the discharge high temperature refrigerant gas on the other side of the exchanger. Along with the suction line accumulator, the Flood Level Control exchanger eliminates the possibility of liquid refrigerant slugging back to the compressor. A Landfill/Digester gas temperature probe in the evaporator s air side tubing reads the temperature and displays it on the control center panel 7. When the Landfill/Digester gas temperature reaches its low setpoint, the compressor will either shut off, or unload, depending upon the mode selected by the operator, thereby saving energy during periods of low load. When the dew point setting is reached, the compressor 8 will resume normal operation. When operating in the cycling mode, a virtually unlimited number of stops and starts is made possible by the Smart Cycle unloader valve 9 opening prior to the starting of the compressor. This allows a 100% unloaded start each time the compressor comes on. When operating in the unloaded mode, heat from compression reduces drastically as the compressor is idling and the warm low pressure refrigerant gas bypasses the condenser 10 and expansion valve 11, and flows through the Static Cooler 12. This core of cold liquid removes heat from the unloaded motor and the cool gas returns to the inlet side of the compressor. Smart Cycle Performance Guarantee Airtek Energy Services Smart Cycle refrigerated Landfill / Digester gas dryers are guaranteed to hold temperature of the Landfill /Digester gas at +33 O F(.5 O C) to +39 O F (3.8 O C) at all operating conditions up to the maximum capacity of the dryer. All Airtek Energy Services Smart Cycle refrigerated Landfill / Digester gas dryers are equipped with a standard digital readout to prominently display the guaranteed Landfill / Digester gas temperature on the control panel.

8 Instrumentation AES Landfill / Digester Gas Dryers are the only refrigerated gas dryers in the world that are equipped with a Digital Dew Point Readout that reads the actual temperature of the landfill / digester gas at the evaporator discharge. Standard Instrumentation Digital Dew Point Temperature Readout Load/Unload Mode Selector Thermal Bank Mode Selector Mode Indicator Switch Adjustable Dew Point Control Power Saver Active Light High Dew Point Alarm Electronic Demand Drain Controller with Alarm & Dry Contacts Diagnostic Code Display Panel Includes Shutdowns With Common Alarm Dry Contacts For: High Dew Point Low Freon Level Low Refrigerant Pressure High Refrigerant Pressure Low Oil Pressure (Semi-Hermetic Compressor) Sensor Fault Refrigerant Overload Optional Panels and Features Digital Readout Landfill/Digester Gas Inlet Temperature Digital Readout Ambient Temperature Warning Light - High Landfill/Digester Gas Inlet Temperature Warning Light - High Ambient or Water Inlet Temperature Landfill/Digester Gas Pressure Inlet Gauge Landfill/Digester Gas Pressure Outlet Gauge Refrigerant Suction Pressure Gauge Refrigerant Discharge Pressure Gauge Compressor Oil Pressure Gauge Disconnect Circuit Breaker Starter With Overloads

9 Control Panel AES s optional Control Center features a complete compliment of data acquisition functions. The easy to use Control Center affords superior dryer control along with digital telemetry, for remote analysis of performance. The Control Center features an Auto mode that will switch standard Load/Unload and Thermal Bank operational characteristics as demand dictates. The Auto Selection innovation will greatly expand the dryer s functionality and utility. The Control Center has a distinctive Flow Schematic with active indicators. Dryer operation is easily reviewed and ascertained. Should any parameter be outside a normal valve, the system schematic annunciates by flashing the source area of the problem, as well as specifically stating details in the LCD display. A load Capacity Meter (LCM) shows the percent-of-burden at which the system is performing at any given moment. The AES Control Center will show everything necessary to know with respect to dryer operations. But that s just the surface...in depth information is available at the touch of a button. Easily navigated menus present dozens of detailed operational data. Every nuance can be studied (or adjusted) revealing both the condition of the dryer, as well as the performance. Included with every Control Center is a communications port making StarWatch Services accessible. AES can monitor and analyze every moment of dryer operation 24-7; it can even do it wirelessly. When StarWatch is activated it will be like an AES technician is right on site, advising your process engineer.

10 Standard Equipment Refrigeration Group Compressor, Semi-Hermetic Compressor Vibration Eliminators (Semi-Hermetic) SmartCycle Loadless Starting SmartCycle Unloader Control - (0-100%) Compressor Crankcase Heater Compressor Isolation Mounts Compressor Suction Unloaders Flood Level Control (patented) Refrigerant, R-22 (CFC Free) High Head Pressure Shutdown Low Suction Pressure Shutdown Thermostatic Expansion Valve Isolation Valves Air Cooled Condenser Low Ambient Fan Controls Liquid Line Filter - Dryer with Replaceable Core Suction Line Solenoid Condenser Pressure Relief Valve Automatic Pump Down Cycle Evaporator Group Tube and Shell Evaporator 304 Stainless Steel Evaporator Tubes Carbon Steel Shell and Epoxy Coated Tubesheet Fully Active Flooded Evaporator Patented Flood Level Control Evaporator Insulation Refrigeration Service Features Isolation Valves * For: All Gauges Condenser Compressor Evaporator Expansion Valve Suction Line Filter Liquid Line Filter Liquid Line Sight Glass Liquid Receiver Patented Flood Level Control Suction Line Solenoid Refrigeration Check Valve * Eliminates the need to pump down & recharge system to repair or component replacement. Diagnostic Codes High Dew Point Low Refrigerant Level Low Refrigerant Pressure High Refrigerant Pressure Low Oil Pressure Sensor Fault Refrigeration Overload Landfill/Digester Gas Circuit Gas to Gas Pre-Cooler/ Re-Heater Heavy Structural Steel Base and Frame with Top Plate Stainless Steel Centrifugal Separator (With Cleanable Mist Eliminator Element) Electronic Demand Drain Drain Isolation Valve 304 Stainless Steel Tubes 304 Stainless Steel Shell 304 Stainless Steel Interconnecting Pipe All Flanges and Tubesheets Are Epoxy Coated

11 Available Options Refrigeration Open Belt Drive Condenser 100% Back-up Compressor 404A Refrigerant Alternative Refrigerant Available Gas Systems 316 Stainless Steel Exchanger Tubes 316 Stainless Steel Exchanger Shell 316 Stainless Steel Separator 316 Stainless Steel Coalescer Stainless Steel Flanges (304SS or 316SS) Stainless Steel Tubesheets (304SS or 316SS) 316 Stainless Steel Interconnecting Piping Condensers Water Cooled Heresite Coated Air Cooled Condenser Electro Fin Plating Refrigeration Z Purge Control Panel (Class1, Div. 2, Group C & D) Any Voltage Heat Tracing NEMA 7 NEMA 9 Outdoor Insulation Instrumentation Control Center StarWatch Services Dual Hour Meters Remote Control Panel 4-20 ma Output For Dew Point PLC Interface Audible Alarm Up To 500 PSI Pressures Package Options Particulate Pre-Filter Coalescing After-Filter Spare Element 3 Valve By-Pass Piping (Pre-Assembled, Shipped Loose) Customized Features Instrumentation Lifting Lugs Factory Supervised Start-Up Export Package Special Paint Color Certified As Built Drawings

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