BID SPECIFICATION QHD SERIES HEATLESS REGENERATIVE AIR DRYER

Transcription

1 quincycompressor.com 701 North Dobson Avenue Bay Minette, AL Phone: Fax: BID SPECIFICATION QHD SERIES HEATLESS REGENERATIVE AIR DRYER 1. SCOPE The specification outlines the requirements for the design, fabrication and supply of a dual tower, automatic, heat less, pressure swing compressed air or gas dryer completely piped, wired, shop assembled and test run as a single unit. 2. GENERAL REFERENCE SPECIFICATIONS The air/gas dryer system shall be designed, fabricated and assembled in accordance with the applicable sections of the following codes, standards, and specifications: A. ASME Boiler and Pressure Vessel Code Latest Edition, Section VIII, Division 1 of unfired pressure vessels. B. ASME Boiler and Pressure Vessel Code Latest Edition, Section IX (Welding Qualification). C. NEMA Standard governing auto-cycling equipment and electrical components. D. National Electrical Code E. ANSI B31.1 Code for Power Piping F. ANSI B16.5 Code for Forged Steel Flanges. G. ANSI B16.9 & ASTM SA-234 for fittings. H. ANSI B16.3 Class 150 Threaded Iron Fittings. I. Inspection and Test Reports. J. Customer Specification K. ISA Instrument Society of America 3. PERFORMANCE REQUIREMENTS The dryer shall be designed to handle the following operating conditions: Fluid: Compressed Air/Gas Capacity: Flow in SCFM 14.7 PSIA Inlet Pressure 100 PSIG (Normal) Design Pressure: 150 PSIG. (Standard) Inlet Temperature: 70 0 F (Minimum) (120 0 F Maximum) Moisture Content: Saturated Electrical Classification: Nema 4 Power Supply: 115V-PH-60HZ Outlet Dew Point: F PDP 1

2 4. BASIC DESIGN A. Design, materials, construction and performance shall be in accordance with Seller s standard practice. B. The design, materials, and construction shall meet all requirements for drying air at the rate and conditions specified. 5. DESIGN FEATURES A. GENERAL 1. The dryer shall be dual tower, fully automatic regenerative type. 2. The dryer shall be assembled on a heavy-duty steel base. The dryer shall be furnished with all the necessary components, equipment and accessories for continuous, fully automatic operation for drying the incoming air with simultaneous reactivation of the idle desiccant bed. 3. The air dryer system shall be fabricated with dual desiccant chambers. Inlet switching valves shall be 2-way non-lube, diaphragms, pilot air operated, normally open (all models through 3,400 cfm). Air outlet valves shall be soft seated, silent check valves. The purge valves are air operated, normally closed, so that in case of power failure or when the unit is de-energized, both the inlet valves are open and the purge valves are closed to avoid any air loss. High performance switching valves with integrally mounted double acting pilot air cylinders, permanent lubrication and a 5 year valve warranty are available on all models The air dryer assembly shall not use any silicone based Material. The gaskets shall be designed for high temperature service and user friendly. 4. The drying flow is upward and regeneration flow is downward. The upward drying flow helps in retaining the contaminants and any liquid carry over at the bottom of the bed. These contaminants are removed at the time of tower depressurization prior to regeneration. The downward regeneration flow direction allows the tower to be rapidly exhausted without fluidizing the desiccant. The instant depressurization of the desiccant bed helps in stripping the moisture from the desiccant bed. 5. The dryer shall be designed to operate on standard NEMA 10 minute time cycle. This 10 minutes cycle is the time required for the desiccant bed to be in drying service, regenerated and returned to drying service. The Sequence of Operation is divided into: Drying- 5 minutes, Regeneration 4 minutes 20 seconds, Re-pressurizing 40 seconds. The dryer designed to provide lower dew point of -100 F shall use a NEMA 5 minute time cycle. 6. The desiccant used shall be Q SORB an enhanced formula of activated alumina that improves adsorption, reduces channeling, reduces pressure drop, lasts longer than ordinary desiccants and is suitable for the operating conditions and dew point specified. The desiccant fill shall comprise of active buffer desiccant at the top and bottom to safe guard the desiccant from being fluidized, minimize the pressure drop, provide full area reactivation and air/gas distribution. 7. The velocity of the air/gas through the desiccant bed shall be less than that which would disrupt, upset or fluidize the desiccant bed. 8. The desiccant towers shall be supplied with removable stainless steel screen. The screens shall be designed to distribute the air/gas flow evenly through the desiccant bed and disperse the dry purge air/gas for desiccant regeneration. 9. Each desiccant bed shall be supplied with separate desiccant fill and drain ports. 10. Desiccant vessels shall be designed, fabricated, tested and code stamped according to the latest edition of ASME Section VIII, Division I Code for Unfired Pressure Vessels. The desiccant vessels shall be designed with 1/16 corrosion allowance. B. REGENERATION SYSTEM 1. Regeneration of the desiccant shall be carried out by means of diverting 14% of the dry process air/gas. The regeneration flow shall be in the opposite direction to the process drying flow. 2. Regeneration of the spent desiccant in off line tower shall be accomplished at atmospheric pressure. The tower to be reactivated shall be depressurized to ambient conditions by blowing down the tower through the purge valves and exhaust mufflers. The air 2

3 required for desiccant reactivation is supplied from the dry process side. The dry air for desiccant regeneration to be regulated with a ball valve and passed through an orifice for flow control. 3. The dry air at almost atmospheric pressure is passed through the saturated desiccant bed. The dry air releases the moisture from the desiccant and is purged out into the atmosphere through the exhaust mufflers. The regeneration period shall last for 4 minutes and 20 seconds. At this time the purge exhaust valve is closed and the tower is re-pressurized to full line pressure through the re-pressurizing valve. C. DEW POINT PERFORMANCE: Provide the air/gas dryer with constant dew point at switch over. Normal -40 F D. CONTROLS 1. An electrical control panel shall be furnished and mounted on the dryer assembly. The panel shall consist of a digital microprocessor controller to sequence the desiccant tower switch over and regeneration automatically. A user friendly LCD display indicates alarm alerts, and actual sequence time in minutes. A sequence annunciator uses LED s to indicate drying status, regeneration status, alarms, and demand cycle indicator (optional). The digital microprocessor control and all electricals are mounted in a NEMA-4 electrical enclosure. The on/off switch and digital microprocessor user interface are located on the electrical enclosure door. 2. Only dry, filtered air may be used for pilot or control air necessary for the operation of the dryer. 3. In the case of loss of power the air dryer will be placed in the fail-safe mode. Both the inlet valves will fail in the normally open position and the purge valves shall fail in the normally closed position. When the power is restored, the operation shall commence from where it had stopped. 4. The dryer shall be equipped with a re-pressurizing circuit to allow gradual rise of regenerating tower to full line pressure prior to switch over. ELECTRONIC CONTOL PROCESSOR FOR QHD HEATLESS DRYERS 1. INTRODUCTION 1.1. GENERAL The Quincy ECP controller is a microprocessor controlled, seven (7) channel recycling timer with LCD and LED display features SEQUENCE OF OPERATION The sequence of operation is based on a five (5) minute or a ten (10) minute NEMA cycle. For either cycle length, one-half of the total time is for adsorption of moisture from the process gas and one-half is for desiccant regeneration. If power is interrupted, the ECP controller electronically stores the point in the timing cycle at which power was removed. When power is reapplied, timing will resume from that point in the cycle. At all times during operation, the current status of the timing cycle is indicated graphically by the LEDs and textually on the LCD screen. 3

4 2. TECHNICAL INFORMATION 2.1. SPECIFICATIONS Input Power: Frequency: Operating Temperature: Time Delays Type: NEMA Cycle: Protection: Dielectric Strength: Insulation Resistance: Mechanical: 120VAC or 230VAC, Single Phase 50 or 60 Hertz 32 F to 122 F (0 C to 50 C) Digital Integrated Circuitry 10 minutes or 5 minutes Transient protected to IEE 587 Level A 2500Vrms 100 M F minimum Control unit with molded housing and encapsulated circuitry. Remote I/O Module is open circuit board construction FEATURES LCD screen indicating R/L tower drying/regenerating, tower switching, actual sequence time, demand cycle indication (opt.), failure to switch alert (opt.) LED sequence annunciator indicating R/L tower drying/regenerating, demand cycle indicator (opt,), high humidity alarm (opt.), failure to switch alarm (opt.) Timer and setting memory Time cycle advance button 5 or 10 minute NEMA cycle selector 3. MODE OF OPERATION: 3.1. START UP The Electronic Control Processor will start to operate as soon as power is supplied and the unit is turned on. The load outputs will recycle on and off based on a 5 minute or a 10 minute NEMA cycle. The point of the sequence at which the timing starts depends on where the cycle stopped when power was last turned off NEMA CYCLE The ECP Controller can be set to operate in a 5 minute NEMA Cycle or a 10 minute NEMA Cycle. The cycle can be selected via a slide switch at the back of the remote I/O module. 4. INHIBIT FUNCTIONS (OPTIONAL) 4.1. DEW POINT DEMAND SEQUENCE CONTROL The demand cycle inhibit function switch will be operational if there are 5 minutes before the end of the drying cycle and the dew point is below the preset level. During dew point demand cycle all of the timing functions stop. The YELLOW LED on the remote I/O will light up and DEMAND CYCLE will be displayed on LCD. As soon as the dew point reaches the preset dew point level the towers will switch and normal cycle will commence. The dew point demand inhibit function will be disabled if the dew point is above the preset level HIGH HUMIDITY The high humidity inhibit is indicated by a red LED on the remote I/O module. The high humidity relay will energize for remote annunciation. All the normal functions will be maintained. 5. RELAY OUTPUTS (DRY CONTACTS) There are two relay outputs for remote annunciation. The output is normally open and rated for 10 AMPS resistive at 125VAC, 5 AMPS resistive at 30VDC. The outputs are for the failure to switch and high humidity alarms. If one or both inhibits are made, the relays will be energized and the LED on the remote I/O will light up. 4

5 CAUTION: The unit may be damaged by electrostatic discharge. Follow procedures for static sensitive parts when handling, shipping or installing this unit. INSTRUMENTATION The dryer assembly shall include the following instrumentation as minimum. 1. Full size Pressure Relief Valve on each tower. 2. Pressure indicator locally mounted on each tower. 3. Control Power On/Off Switch 4. Electronic Control Processor Operator Interface 5. Pilot air control filter with service valve E. FILTERS (Optional Accessory) 1. Provide Coalescing Filter upstream and Particulate Filter downstream of the air/gas dryer. The coalescing pre-filter shall be rated for 0.3 micron and the particulate after-filter shall be rated for 3.0 micron. 2. The pre-filter shall be supplied with automatic drain with isolation valve and an auxiliary manual drain valve. The after-filter shall be supplied with manual drain valve. 3. Each filter shall be assembled with high differential pressure gauge. 4. OPTION: Single or Dual filters installed on the dryer skid or a separate skid with Isolation and bypass valves for servicing or replacing the filter elements. F. PIPING & FITTINGS Standard dryers are constructed with SA53B, black steel pipe Schedule 40 conforming to ANSI B Pipe fittings are black malleable iron fittings conforming to ASTM A197 specification. The fittings 1/4 to 2 size are Class 150 threaded, designed to conform to ANSI B16.3. All piping and fittings 2-1/2 and larger are butt weld SA234WPB with SA150 slip-on or weld neck flanges conforming to ANSI B31.3. G. ELECTRICAL 1. In the case of power supply over 120V, the panel shall include control transformer with primary and secondary circuit fuses. 2. The controls shall operate on 120 volts, 60 hertz, 1 phase power. 3. Electrical construction shall be in accordance with NEMA area classification and shall be wired in accordance with NEC requirements. 4. All the wiring shall be numbered and end in terminal block. Splicing of the wires shall be avoided. Each terminal shall hold only two wires. 5. Provide the PLC with Master Advance Switch to manually advance through the sequence and help in trouble shooting. 6. Provide dry contacts for all alarm conditions for customer annunciation. A. DIGITAL DEW POINT DEMAND An automatic moisture load control system shall be provided to reduce the total operating cost during periods of low moisture loading and extend the life of the equipment and desiccant resulting in lower operating and desiccant replacement cost. The digital dew point demand control is an energy saver that can extend the drying cycle without purging during periods of lower moisture loads. The dew point demand system offers in on compact package, the utmost in flexibility and accuracy sensing the actual dew point of the outlet air. The hygrometer senses the dew point at the outlet of the dryer at the end of the drying cycle, 5

6 and extends the drying cycle until the preset adjustable dew point set point is reached. During this extended drying cycle, the purge valves are closed and the opposite tower is pressurized and prepared for the drying cycle. The digital dew point demand option reduces purge loss and extends valve life. This option includes an adjustable high humidity alarm set point and a digital dew point display. The system is designed to automatically default into the fixed cycle if the signal from the probe is not received. Digital Dew Point Demand Standard Instrumentation is as follows: Digital dew point display Adjustable set points High Humidity alarm light with dry contact 4-20 ma output signal tracking the dew point This system shall accomplish the following: 1. Sample the moisture content of the air leaving the dryer by means of a moisture sensor. 2. Provide a moisture analyzer with digital dew point display. This will give a visual indication of the actual outlet air dew point performance and operation of the dryer. 3. Initiate the tower switch over only when the outlet moisture content rises to a preset dew point on the analyzer. 4. Control all functions of the dryer so that complete reactivation of the idle tower is accomplished. 5. Provide the dew point analyzer with 4-20 MA Output signal for remote annunciation. The dew point set points should be field adjustable. 6. Provide the dew point analyzer with a second output. This will energize contact for alarm condition if the moisture content of the discharge air reaches an unacceptable level. A light is provided on the control panel for visual indication. 7. In case of the dew point analyzer or moisture sensor malfunction, the sequence should automatically change to the normal cycle. 8. Provide a manual over-ride switch to change the sequence between the normal cycle and demand cycle. 9. The probe shall be protected from normal wear and tear by a rugged stainless steel enclosure and the ceramic sensor shall be protected by a sintered metal guard. Calibration data shall be stored directly in the sensors memory. The instrument shall be equipped with an internal thermistor to compensate for fluctuating temperatures. The probe shall be certifiable and traceable to the National Institute of Standards and Technology. The system shall provide dry contacts for remote alarms and a scaled 4 to 20 ma linear output. Optional RS232 or RS485 communications ports shall be available. B. -94 DEW POINT (Optional) 1. Provide a mixture of molecular sieve desiccant in the drying towers. 6. FINISH AND PAINTING The finishing and painting shall be according to the manufacturer standard procedure. 1. Remove grease, dirt and dust from steel and iron surfaces by cleaning with solvents or inorganic detergents. 2. Remove rust, scales and heavy coatings of paint by wire brushing or sanding. 3. Remove all weld spatters by dipping or grinding. 4. Immediately prime any bare metal 5. Prime all welds as soon as it is cool to prevent any rust formation on the bare metal. 6. Prime all the bare metal with red primer. 7. Finish Paint with standard enamel. 6

7 8. INSPECTION AND TESTING The completed dryer assembly shall be Inspected and tested according to the Inspection and Test Procedures. 1. The air dryer assembly shall be leak tested pneumatically at 1.25 times the normal operating pressure with soap bubble pressure test. 2. The dryer shall be tested at no load through its complete sequence of operation. 3. All the alarm conditions shall be tested for their function. 4. All the control settings shall be tested and recorded. 5. The completed shop test report shall be submitted with the dryer. 9. SHIPMENT The Manufacture shall provide the following minimum for Shipment. 1. All the nozzles shall be plugged or sealed with protective covers. 2. Wrap the Electrical enclosure with polyethylene sheet. 3. Place a small bag of desiccant in the enclosure. 4. Place the Installation, Operation and Maintenance Manual with the shop test report in the Enclosure or tape it on the side. 7