Ferro Alloy Secondary Ventilation

MikroPul Pittsburgh Proposal 0262-11

August 5, 2011

MikroPul Pittsburgh proposes to supply a new Mikro-Pulsaire Pulse Jet system to treat 

the emissions from Ferro Alloy tap hole, runner, ladle and casting bins ventilation process 

to be located in XXXXXX. The equipment and services proposed will be designed to 

meet the following parameters.

Gas Volume, Design: 150,000 ACFM

Maximum Operating Gas Temperature: 275° F

Normal Operating Gas Temperature: 200° F

Dust Loading (average) Less than 1.0 grains / actual cubic feet 

Outlet Loading requirement: Less than 0.0022 gr/dscf

Number of Modules: Six (6)

Module Cloth Area: 8,456 square feet

Total Cloth Area: 50,736 square feet

Net Cloth Area: 42,280 square feet with Five (5) modules 

filtering

Gross Air : Cloth Ratio: 2.96 : 1

Net Air : Cloth Ratio: 3.55: 1

Dust Filtered: Metal fume

Application: Submerged arc furnace tap hole, runner, ladle 

and casting bins

Pulse cleaning mode: off or on-line

Baghouse Equipment

Six (6) Model 323(6)-16-20 TRH Mikro-Pulsaire top removal walk-in plenum dust 

collector module in a 2 x 3 arrangement. Each module is furnished with the following:

Inlet Design: Patented CascadairTM design distribution inlet device 

is proven to: 

 Provide extended bag life

 Lower pressure drop

 Reduce compressed air consumption

 Dispense air evenly

 Dramatically reduce maintenance and energy 
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 costs

 Reduce dust retention on filters

Filter Bags: (1,938) 6.25 in. dia. x 16 ft. long 

16 oz./(sq. yd.), Density Polyester with PTFE finish on one 

side, triple sewn felt bags. 

STYLE : POLYESTER FELT WITH 

MEMBRANE 

FIBER : POLYESTER 

WEIGHT : NOMINAL 16.0 OPSY 

SCRIM : FIBER SUPPORTED 

PERMEABILITY : 7 - 12 CFM 

MECH TREATMENT : PTFE MEMBRANE APPLIED 

THICKNESS : 0.0550"- 0.0850" 

TENSILE : MINIMUM WARP 75 LBS -

FILL 150 LBS. 

MULLEN : MINIMUM 375 PSI 

SHRINKAGE : MAXIMUM 3 % FOR 2 HRS 

AT 300 DEGREES F.

Retainers: Total 1,938 galvanized carbon steel, one piece construction 

retainers complete with integral venturi consisting of 12 

vertical 1/8 in. dia. wires with horizontal rings spaced on 8 

in. centers. All wires and horizontal rings are welded to the 

inside of the retainer, eliminating bag wear and premature 

filter failure. All retainers have been fully inspected to 

ensure there are no burrs, which can rub against the bags to 

cause leakage.

Assembly to be Snap Band type.

Housing: 3/16 inch carbon steel, welded construction furnished 

complete with design rating of ±20 inches of water for dust 

tight service. The collector housing is fully welded 

eliminating possible dust leakage.
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Hopper: 3/16 inch carbon steel, pyramid type with 60 degree side 

slope furnished complete with one (1) 24-inch squared 

hinged and clamped access door. Hopper supplied with 

flanged discharge for 12-inch valve. Each hopper to have 3-

inch dia. pipe nipple with threaded cap to rod out the hopper 

section above the discharge.

Clean Air Plenum: 3/16 inch steel, welded construction, walk-in plenum type, 

complete with one (1) hinged and clamped access door and

one (1) exhaust connection.

Inlet Manifold: 3/16 inch carbon steel manifold to evenly distribute the dustladen gas to each of the Six (6) modules. The manifold 

features bottom discharge (self-cleaning) design. The 

manifold will be stiffened for ±20 inches of water.

Outlet Manifold: 3/16 inch carbon steel manifold to evenly collect the cleaned 

gas from each of the Six (6) modules. The manifold will be 

stiffened for ±20 inches of water.

Tube Sheet Assembly: 3/16 inch carbon steel, bolted between plenum and housing 

flange, with openings for snap band bag and retainer 

assembly. Holes are on 8-inch center spacing in both 

directions.

Cleaning Assembly: The Mikro-Pulsaire has a rugged air distribution system 

that features thorough cleaning with no internal moving 

parts and an automated self-cleaning system that utilizes 

momentary jets of high-pressure air through a specially 

designed venturi to provide efficient, thorough cleaning. 

Consisting of a carbon steel air supply header, brass 

solenoid valves in NEMA 4 enclosure, MikroPul right angle 

valves, aluminum construction, factory installed to the 

collector plenum section. Specially designed, stiffened 

blowpipes included. 

Pulse Control: By local pulse timer, controlled by PLC, see below. Three 

modes of pulse operation would be available, 1) overall high 

dP; 2) timed sequence and; 3) manual override. Individual 

module pressure drop will be monitored as well as overall 

baghouse pressure drop.
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Electrical, Process Typical description Main PLC Control Panel consisting of 

the following:

Controls:

• 110vac power supplied to panel by customer

• NEMA 12 enclosure painted RAL 7035

• Siemens S7-315 PLC with 20% spare I/O

• Siemens TP177B, 5.7” color touch screen

• Siemens 1 pole circuit breaker for incoming 110vac 

power

• Receptacle provided for laptop connection

• Terminals, wire duct, wire, etc., as required

Inlet Dampers: Each module is equipped with a fabricated 50-inch dia., 

manually operated butterfly type damper. Open and Close 

limit switch included for each damper. This damper to be 

used during maintenance.

Outlet Dampers: Each module is equipped with a fabricated 50-inch dia., air 

cylinder operated butterfly type damper. This damper is to 

be used for isolation during offline cleaning mode. Open 

and Close limit switch included for each outlet damper.

Module Supports: Structural support steel for local wind, seismic, equipment 

live and dead loads as applicable shall be provided. The 

clearance under the fabric filter hopper flange shall be Six 

(6) feet. Hopper loads for structural design are based upon 

the hoppers being 2/3 full by volume and with a bulk density 

of 70 lbs./cubic foot.

Module Access Platform: A common service platform between rows of modules is 

located at the tubesheet level. The platform is constructed 

from steel bar grating with bar and angle type handrail and 

kick plate is included at each end of the walkway.

Stairs: One (1) 48” wide stairway from grade to the tube sheet 

level. 10” wide bar grating treads with checkered plate 

nosing, bar and rod handrail are also provided.

Ladder: One (1) caged ladder system will be provided from tube 

sheet level to grade. 
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Rotary Valves: Six (6) 10” rotary valves, cast iron construction with vane 

wipers for connection to each pyramid hopper outlet flange. 

Each rotary valve is driven by a 1 HP gear motor.

Painting: All structural steel work and exterior surface of modules 

shall be primed and enamel finish painted (direct to metal) 

in the shop following an SSPC-SP2 and/or SP3 surface 

preparation. 

Instrumentation:

Module Timers Each module includes a clean on demand timer in a NEMA 

4X enclosure. 

Module DP Transmitter: Six (6) differential pressure transmitters are provided for 

remote indication of the module pressure loss as measured 

across the tube sheet The transmitter is a 0-20” W.C. range 

with a 4-20 mA output signal. 

System DP Transmitter: One (1) differential pressure transmitters are provided for 

remote indication of the baghouse pressure loss as measured 

from the inlet plenum to the outlet plenum. The transmitter 

is a 0-20” W.C. range with a 4-20 mA output signal. 

Leak Detection System: The baghouse shall be equipped with Six (6) leak detection 

probes to provide continuous monitoring of each module.

The output from the leak detection system shall be sent to 

the PLC.

Each probe will send a 4-20 mA signal.

Proximity Switches: Proximity switches (zero speed type) to be provided at each 

rotary air valve, Six (6) total.

Limit Switches: Open and Close limit switches are included for each module 

inlet and outlet damper, Twelve (12) total.

Hopper Level Probes: Capacitance type level probes to be provided for each 

hopper, Six (6) total. Model CLSI (or equal) detects the 
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presence or absence of material in contact with the probe by

sensing a change in capacitance.

Thermocouples: One (1) thermocouple with transmitter is provided. 

Manifold Pressure Regulators:Six (6) pressure sensors, one for each module

Compressed Air Pressure Transmitter: One (1) provided

Air Moving Equipment:

Air Moving Equipment and Accessories:

MikroPul will solicited fan quotations from various fan vendors and expects to negotiate 

with all of the bidders before award of a purchase order.

Main ID Fan: One (1) induced draft centrifugal, DWDI (double width, 

double inlet), Arrangement 3, heavy-duty exhaust fan with 

backward curve blades. 

The fan is selected to operate at 150,000 ACFM 

at 200°F and 18 inches of water.

Rated at 150,000 ACFM @ 18” and 200° F

1,200 RPM 

Electric variable position damper actuator (Beck)

Anti friction bearings

Bearing vibration and temperature ready

Inlet and outlet flexible isolation joints

Inlet boxes with louver dampers

Gear coupling half mounted to fan shaft

Drains with caps

Split housing for wheel removal

Clips for insulation to be provided by installation contractor

Main Fan Bearing Each main fan bearing shall be equipped with a vibration

Vibration Sensors: sensor pick-up. The output shall be for monitoring and 

alarm with shutdown on high set point.
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Main Fan Bearing Each main fan bearing shall be equipped with one (1) RTD

Temperature Sensors: sensor with 4 to 20 milliamp output. The output shall be for 

high temperature alarm.

Main Fan Inlet Electric inlet damper actuators shall be provided capable of

Damper Actuators: variable position continuous modulating control with 4 to 

20 ma positioner. Linkage for mounting of the damper 

actuator at grade on a separate pedestal.

(Main Fan Motor): 900 HP 1200 RPM induction motor. The motor will be 

rated for 4160V/3ph/ 60Hz TEAAC operation with a 1.15 

service factor. Motors shall include stator RTDs, bearing 

vibration and temperature sensors, and space heaters.

Ductwork / Hoods / Stack & Installation 

1. Unload, assemble and erect on concrete pads/piers furnished by others, Six (6)

MikroPul Model 323(6)-16-20 TRH Mikro-Pulsaire dust collectors including:

• One (1) lot of structural support steel

• Hoppers

• Clean Air inlet manifold

• Dirty Air Outlet Mainfold

• Tube sheet assemblies

• Walk-in plenums

• Cleaning assemblies

• One (1) Rotary air lock valve for each hopper

• One (1) hopper slide gates for each hopper

• One (1) common access platform

• One (1) caged access ladder

• One (1) access stairway

• Siding girts

• Total of 1,292 filter bags and cages

2. Furnish and install all required piping and shutoff valves to connect Eramet supplied 

compressed air to the Four (4) cleaning systems.

3. Unload, assemble and anchor in place on concrete pads, one (1) 150,000 CFM fan.

4. Design, fabricate and install two (2) Hoods (one approx. 8 ft. x 10 ft. over tap hole and 

one approx. 10 ft. x 20 ft. over ladle) and transition ductwork to form a 36 inch 

diameter trunk. 

• Hoods to be fabricated out of 3/16” A-588 Corten or A-36 mild steel
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• Transition piece Suitably stiffened for required static pressure using mild steel 

angle

• Flanged connections using mild steel angles

• Mild steel structural support towers 

• expansion joint as required

• include positioning dampers in duct prior to each hood (30% to tap hole and

70% to ladle

5. Design, fabricate and install 76 inch diameter ductwork from the transition piece to the 

baghouse, to the fan and from the fan to the stack.

• Duct will be fabricated out of 3/16” A-588 Corten or A-36 mild steel

• Suitably stiffened for required static pressure

• 76 in diameter or sized at approx. 3,800 FPM

• Based on 200 ft straight run to Pulse Jet

• Flanged connections

• Mild steel structural support towers with saddles

• One (1) expansion joint fan inlet box

6. Design, fabricate and install one (1) 7’-0” diameter by approx 65’-0” tall stack 

including:

• Stack shell will be fabricated out 3/8” and 1⁄4” mild steel plate

• Stack base will be fabricated out of 1” mild steel plate with 1” upper support 

ring

• One (1) inlet breechings with stiffeners

• Two (2) 6” diameter test ports

• One (1) 180 degree access platform

• Caged access ladders with intermediate rest platforms up to 180 degree test 

port access platform

• Expansion joints from fan outlet to the stack inlet breeching

9. Leak test filter bags.

10. Precoat filter bags.

11. Start up assistance.

12. Structural steel support towers, saddles and stack will receive one shop coat of 

industrial enamel.

13. 4 inch mineral wool with aluminum cladding Insulation for main ID fan to reduce 

noise levels
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Purchaser to Furnish

• Any required taxes.

• Means of cooling the gas to a maximum of 275°F prior to the MikroPul interface.

• All duct work not mentioned above

• Fire protection or explosion suppression equipment if required

• Thermal or sound insulation if required.

• Electrical service for all MikroPul supplied equipment.

• Means of collecting dust from Rotary airlock outlet.

• Foundations.

• MCC.

• Lighting.

• All motor starters.

• All building permits and licenses.

• FAA approval for stack and stack aviation lights if required.

• Tax Exempt Certificate at time of order placement.

• Disposal of all removed materials from the plant property if required.

• Stack sampling and testing if required.