Landfill gas is generated by the anaerobic decomposition of organic matter deposited in landfills. Digester gas isproduced as a by-product of the digestion of sewage sludge. The effluent gas consists mostly of methane andcarbon dioxide together with water vapor and minor quantities of organic compounds. The Airtek EnergyServices (AES) Landfill/Digester Gas Dryers remove moisture and impurities so the gas can be utilized as fuelsource 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.

Patented Smart Cycle control reduces energy consumption and maintains a constant dew point by loadingand unloading or by turning refrigeration compressor on or off in direct response to the actual dew pointtemperature of the gas.

Patented dew point sensor precisely monitors the temperature of the gas. The gas temperature isprominently displayed on the control panel.

Patented Flood Level Control increases dryer efficiency and protects refrigerant compressor fromfloodback.

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% efficient @ 5 micron andlarger.

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 theentire charge, minimizing service and downtime.

Landfill & Digester Gas Dryers

Features and Benefits

0% Load 50% Load 100% Load

ENERGY USE COMPARISON

100% Power

50% Power

0% Power

AES’s patented Smart Cycle demand control reduces energy consumption and maintains a true and constant dewpoint by loading and unloading or by turing the refrigeration compressor on or off in direct response to the actualdew point temperature of the gas. The Smart Cycle control automatically adjusts for constantly changing operatingand inlet conditions.

Direct dew point sensing and control assures the lowest possible dew point, driest gas, and significant energysavings. The Smart Cycle employs a patented, quick acting temperature sensor to precisely monitor thetemperature of the landfill/digester gas at the evaporator discharge and either adjusts the load/ unload cycleaccordingly or turns the refrigeration compressor on or off when in the Thermal Bank Mode.Whether therefrigeration compressor is loaded, unloaded, on or off, is determined directly by the rising and falling dew pointtemperature of the gas.The dew point ranges from low setting of +35OF to the upper set point point of +39OF (setpoints are adjustable).

Smart Cycle Demand Control

When the refrigeration compressor is completely unloaded,about 50% of full load power is used. When the compressorcycles in the Standby/Off position, no energy is being consumed.

Smart Cycle Energy Savings

The Landfill/Digester Gas Series Dryers use high efficiency, non-fouling, tube and shell heat exchangers. They aresimple, reliable, and time proven.AES directs the flow of raw gas through straight, smooth bore, 304 stainlesssteel tubes that are surrounded by cold gas in the pre-cooler/ re-heater and colder liquid refrigerant in the mainevaporator.This envelope of cold allows the Landfill/Digester Dryers to achieve and maintain optimumperformance and dew point within minutes of start up. The fully active, flooded evaporator eliminatesevaporator 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 flowrestrictions are eliminated.The heat exchangers do not foul and

pressure differential is kept to a minimum.

Due to the limited number ofmechanical connections and clear flow

path,AES heat exchangers requirelittle, if any, maintenance. Mostother types of dryers direct theflow of dirty air through the shellof the heat exchanger where thedirt and oil collect on the tubesand surfaces. Since these heatexchangers are not cleanable,efficiency is lowered and energyconsuming pressure drop increasesas soon as it is put into

service.

Heat Exchangers

Grooved Tube Sheets

An Airtek ExclusiveEach Tube Sheet Hole Has Precision Milled GroovesLeak-proof JointsGreater Mechanical Strength

AES Landfill/Digester Gas Dryers are equipped with a factoryinstalled “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 levelswitch assuring complete drainage. The Electronic Demand Draineliminates fouling, pressure loss and manual adjustments associatedwith timed drains. Failure alarm with remote contacts are standard.

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 oncompetitors’ dryers.

Eliminates the need to attempt precision adjustments on the thermostatic expansion valve.

Cool Dry Gas and OilTo refrigeration

compressor inlet

Cold Gas / Liquid Refrigerant and Oil MixBoiling Over From Evaporator

Hot Gas From Compressor Hot Gas Out To Condenser

Patented Flood Level Control

Electronic Demand Drain

Flow Schematic

Saturated gas enters the tubes of the gas to gas Heat Exchanger 1 where it is pre-cooled bythe cold gas returning through the shell from the evaporator. Pre-cooling saves energy byreducing the heat load on the refrigeration system.After the gas has been pre-cooled, it flowsinto the evaporator tubes 2 where the temperature is lowered to approximately +34OF.Thetemperature reduction forces water and oil vapor to condense. The mixture of coldlandfill/digester gas and condensed liquid flows into the mechanical moisture separator 3 withMist 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 itsvolume is increased through reheating. The processed landfill/digester gas enters the maindistribution system 5 as a dry, clean and efficient utility.

AES’s patented refrigeration system enables the use of a fully active flooded evaporator 2 . Landfill/Digester gas flowsthrough the submerged tubes in the flooded shell to ensure dew point integrity. This is made possible because therefrigerant 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 hightemperature refrigerant gas on the other side of the exchanger.Along with the suction line accumulator, the FloodLevel 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 onthe control center panel 7 . When the Landfill/Digester gas temperature reaches its low setpoint, the compressorwill either shut off, or unload, depending upon the mode selected by the operator, thereby saving energy duringperiods 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 SmartCycle unloader valve 9 opening prior to the starting of the compressor. This allows a 100% unloaded start eachtime the compressor comes on.

When operating in the unloaded mode, heat from compression reduces drastically as the compressor is idling and thewarm low pressure refrigerant gas bypasses the condenser 10 and expansion valve 11 , and flows through the StaticCooler 12 . This core of cold liquid removes heat from the unloaded motor and the cool gas returns to the inlet sideof the compressor.

Patented Refrigeration Circuit

Smart Cycle®

Performance GuaranteeAirtek Energy Services Smart Cycle refrigerated Landfill / Digester gas dryers areguaranteed to hold temperature of the Landfill /Digester gas at +33OF(.5OC) to

+39OF (3.8OC) at all operating conditions up to the maximum capacity of the dryer.

All Airtek Energy Services Smart Cycle refrigerated Landfill / Digester gas dryers areequipped with a standard digital readout to prominently display the guaranteed

Landfill / Digester gas temperature on the control panel.

Landfill / Digester Gas Circuit

AES Landfill / Digester Gas Dryers are the only refrigerated gas dryers in the world that areequipped with a Digital Dew Point Readout that reads the actual temperature of the landfill /digester gas at the evaporator discharge.

Digital Dew Point Temperature ReadoutLoad/Unload Mode SelectorThermal Bank Mode SelectorMode Indicator SwitchAdjustable Dew Point ControlPower Saver Active LightHigh Dew Point AlarmElectronic Demand Drain Controller with Alarm & Dry Contacts

Digital Readout Landfill/Digester Gas Inlet TemperatureDigital Readout Ambient TemperatureWarning Light - High Landfill/Digester Gas Inlet TemperatureWarning Light - High Ambient or Water Inlet TemperatureLandfill/Digester Gas Pressure Inlet GaugeLandfill/Digester Gas Pressure Outlet GaugeRefrigerant Suction Pressure GaugeRefrigerant Discharge Pressure GaugeCompressor Oil Pressure GaugeDisconnectCircuit BreakerStarter With Overloads

Diagnostic Code Display PanelIncludes Shutdowns With Common Alarm DryContacts For:

High Dew PointLow Freon LevelLow Refrigerant PressureHigh Refrigerant PressureLow Oil Pressure (Semi-Hermetic Compressor)Sensor FaultRefrigerant Overload

Instrumentation

Standard Instrumentation

Optional Panels and Features

Control Panel

AES’s optional ControlCenter features a completecompliment of dataacquisition functions. Theeasy to use Control Centeraffords superior dryercontrol along with digitaltelemetry, for remoteanalysis of performance.The Control Center featuresan “Auto” mode that willswitch standard“Load/Unload” and “ThermalBank” operationalcharacteristics as demanddictates. The Auto Selectioninnovation will greatlyexpand the dryer’sfunctionality and utility.

The Control Center has adistinctive “Flow Schematic”with active indicators. Dryeroperation is easily reviewedand ascertained. Should anyparameter be outside anormal valve, the systemschematic annunciates by

flashing the source area of the problem, as well as specifically stating details in the LCD display. A loadCapacity Meter (LCM) shows the percent-of-burden at which the system is performing at any givenmoment.

The AES Control Center will show everything necessary to know with respect to dryer operations. Butthat’s just the surface...In depth information is available at thetouch of a button. Easily navigated menus present dozens ofdetailed operational data. Every nuance can be studied (oradjusted) revealing both the condition of the dryer, as well asthe performance.Included with every Control Center is a communications portmaking StarWatch Services accessible. AES can monitor andanalyze every moment of dryer operation 24-7; it can even doit wirelessly. When StarWatch is activated it will be like anAES technician is right on site, advising your process engineer.

Compressor, Semi-HermeticCompressor Vibration Eliminators (Semi-Hermetic)SmartCycle® Loadless StartingSmartCycle® Unloader Control - (0-100%)Compressor Crankcase HeaterCompressor Isolation MountsCompressor Suction UnloadersFlood Level Control (patented)Refrigerant, R-22 (CFC Free)High Head Pressure ShutdownLow Suction Pressure ShutdownThermostatic Expansion ValveIsolation ValvesAir Cooled CondenserLow Ambient Fan ControlsLiquid Line Filter - Dryer with Replaceable CoreSuction Line SolenoidCondenser Pressure Relief ValveAutomatic Pump Down Cycle

Tube and Shell Evaporator304 Stainless Steel Evaporator TubesCarbon Steel Shell and Epoxy Coated TubesheetFully Active Flooded EvaporatorPatented Flood Level ControlEvaporator Insulation

Isolation Valves* For:

All GaugesCondenserCompressorEvaporatorExpansion ValveSuction Line FilterLiquid Line FilterLiquid Line Sight GlassLiquid ReceiverPatented Flood Level ControlSuction Line SolenoidRefrigeration Check Valve

* Eliminates the need to pump down & recharge system to repair or component replacement.

Standard Equipment

Refrigeration Group Refrigeration Service Features

Evaporator Group

Gas to Gas Pre-Cooler/ Re-HeaterHeavy Structural Steel Base and Frame with Top PlateStainless Steel Centrifugal Separator (With Cleanable Mist Eliminator Element)Electronic Demand DrainDrain Isolation Valve304 Stainless Steel Tubes304 Stainless Steel Shell304 Stainless Steel Interconnecting PipeAll Flanges and Tubesheets Are Epoxy Coated

Landfill/Digester Gas Circuit

High Dew PointLow Refrigerant LevelLow Refrigerant PressureHigh Refrigerant PressureLow Oil PressureSensor FaultRefrigeration Overload

Diagnostic Codes

Available Options

Open Belt Drive Condenser100% Back-up Compressor404A RefrigerantAlternative Refrigerant Available

RefrigerationZ Purge Control Panel (Class1, Div. 2, Group C & D)Any VoltageHeat TracingNEMA 7NEMA 9Outdoor Insulation

Refrigeration

Control CenterStarWatch® ServicesDual Hour MetersRemote Control Panel4-20 mA Output For Dew PointPLC InterfaceAudible Alarm

Instrumentation

Up To 500 PSI

Pressures

Lifting LugsFactory Supervised Start-UpExport PackageSpecial Paint ColorCertified “As Built” Drawings

Instrumentation

Water CooledHeresite Coated Air Cooled CondenserElectro Fin Plating

Condensers

Particulate Pre-FilterCoalescing After-FilterSpare Element3 Valve By-Pass Piping (Pre-Assembled, Shipped Loose)Customized Features

Package Options

316 Stainless Steel Exchanger Tubes316 Stainless Steel Exchanger Shell316 Stainless Steel Separator316 Stainless Steel CoalescerStainless Steel Flanges (304SS or 316SS)Stainless Steel Tubesheets (304SS or 316SS)316 Stainless Steel Interconnecting Piping

Gas Systems

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