Post on 29-Jul-2015
transcript
New Electrostatic Precipitator Technologies in
the Pulp & Paper Industry
Charles Hayes
Regional Sales Director
SOUTHERNenvironmental ,INC
.
Pensacola, Florida
Introduction
New technologies which may be of particular
interest in the Brazilian Pulp & Paper Industry
• Customized discharge electrodes to reduce outlet emissions
• High frequency SMPS to replace conventional T/R sets
• New techniques for better gas distribution
• Top-rapped ESP design – advantages compared to “European” design
• ESP Conversion – Tumbling Hammer to Top-rapped design – a case study
Techniques to improve performance
in ESP Rebuilds/Upgrades
Your logo • Customized RDEs
• Increase Electrical Sectionalization
• Increase Rapping Sectionalization
• Enhance ESP Flow Distribution by Modeling
• Enhance Hopper & Anti-Sneakage Baffling
• Advanced SMPS Power Supplies
• Convert Tumbling Hammer to Top-Rapped design
ELEX Rigid Discharge Electrode
• Rigid –Unbreakable – Electrode Design
• Variable Emitter Point Settings
• Variable Emitter Tab settings
• Low Corona Onset Voltage
• Uniform Current Distribution to Plates
• Plate Spacing Between 250 and 400 mm
ELEX Rigid Discharge Electrode
• Customized throughout ESP fields
• More Points – for high dust load in Inlet Fields
• Superior in overcoming space charge effects
• Optimum Particulate Charging
• Eliminates lower frame spit sparking
ELEX RDE Configurations
Aggressive – More
points per meter
Standard – fewer
points per meter
ELEX Rigid Discharge Electrode
(Optimized)
ELEX VRS Pipe & Spike
ELEX vs. Pipe & Spike
Airload V-I Curves
Top-Rapped ESP Internals
Internals showing DE & CE Rappers
Collecting Plate Design
• 1.3 – 1.6 mm thick A-366 Steel
• 445 mm Segments or Opzels
• Cold roll Formed
• Edge Arc-Over Prevention
• Uniform Thermal Movement
Rapping System
• Design Objectives: • To Clean Collecting and Discharge Electrodes
• Minimize Re-entrainment, Stack Puffs, and Back Corona
• Maintenance Needs: • Reliability, Low Maintenance, and Serviceability
• Types: • Electromagnetic, Hammer, and Vibrators
ICAC Gas Distribution Criteria
• 3.2.1 Guaranteed precipitator operating efficiency. Gas flow uniformity becomes
• increasingly important as operating efficiencies approach 100% due to:
• 3.2.1.1 The tendency for the smaller particles to follow the gas flow streamlines more
closely.
• 3.2.1.2 The increased need for almost total suppression of gas bypassing and hopper
sweepage. Thus, the higher the guaranteed operating efficiency of a precipitator, the more
important the optimization of the gas flow.
• 5.1.1 Within the treatment zone near the inlet and outlet faces of the precipitator collection
chamber, the velocity pattern shall have a minimum of 85% of the velocities not more than
1.15 times the average velocity, and 99% of the velocities not more than 1,40 times the
average velocity. Average velocity refers to the mean of all velocity measurements made at
a given face of the precipitator.
• Copied from: Institute of Clean Air Companies – Publication ICAC – EP- 7
CFD of Recovery Boiler ESP
High Frequency Power Supply
Features
• Operating Frequency = 25 kHz compared to 50
to 60 Hz for conventional T/R set energization
• Typically provides 10% increase in secondary
voltage & about a 25–40% increase in secondary
current
• 3-phase input results in higher power factor
• Performance Enhancement Factor (w’/w) for
moderate to low resistivity applications
• Similar installed cost as conventional T/R sets
SMPS offer Big Benefits
• More efficient – up to 30% more power into the ESP
• Combines T/R, controller, Reactor and ground switch in one package
• Higher power factor (.94 vs .63) means lower power consumed per kw of power to ESP
• Easier to install – no AVC room
• Field serviceable – plug-in, plug-out components
• Smaller & lighter than Traditional T/R’s
• Less/limited bus duct required
[ms]
[kV]
0
20
40
60
80
Conventional T/R
SMPS
Time (ms)
ESP
Current
[mA]
SMPS wave form vs conventional T/R
SMPS - No Ripple
New High Frequency Power Supply
70 kV@1000mA SMPS Smaller & lighter
SMPS INSTALLATIONS
• Results and Benefits
• More power into ESP
• Lower emissions
• Less line power consumed
Electromagnetic Rapping Advantages
• External Location Allows Online Servicing
• Control Sequencing, Timing, Rapping Forces
• Same Rapping System on CEs & Des – Copper coil (10 kg)
– 27 joules capacity
– Variable intensity
– 10 kg Piston with Stainless Steel Tip
Common Parts for All Rapping Systems
Modern Rapper Controls
• Microprocessor Control
• Password protected
• Variable duration, lift, and sequence
• Anti-coincidence Grouping
• Rapper failure alarms
• Remote display option with fiber optics
• Multiple rapper programs
• DCS compatible
Top-Rapped
vrs Tumbling Hammer Design vrs Tumbling Hammer Design
Top Rapped
Tumbling Hammer
• Two- point suspension
• MIGI Rappers
• Rappers out of gas stream
• Variable rapping frequency
• Variable rapping intensity
• Short (1 m – 4 m) field length
• 0.3 m – 0.5 m between-field
length
• Typically penthouse design
• Typically single CE plate
• Heavy duty, reliable DE’s
• Four point suspension
• Tumbling hammers
• Rappers in gas stream
• Variable rapping frequency
• Fixed rapping intensity
• Large (2 m – 5.5 m) fields
• 1.5 m – 5.5 m between-field
space required
• Insulator Compartments
• Panel plate assembly
• DE’s subject to breakage &
tension loss
Top-Rapped
vrs Tumbling Hammer Design
• Multiple CE plates per rapper
• Typical CE rapping ratio -
< 138 m2 per rapper
• Customizable DE emitter
points
• Straightforward assy of DE
• Bottom frame simplifies
alignment
• More shop fabrication –
lower field erection cost
Typical CE rapping ratio - Typical CE rapping ratio - Typical CE rapping ratio - Typical CE rapping ratio -
• One CE plate per rapper
• Rapping ratio could be
higher w/long field
• Limited customization
possible
• Frame assembly is field-
labor intensive
• No bottom frame
• Overall field erection is labor
intensive
Tumbling Hammer TOP RAPPED
Top-Rapped
vrs Tumbling Hammer Design
• Typically smaller ESP for a
given gas flow
• Greater cost effective
electrical sectionalization
available
• Minimal internal maintenance
• Routine maintenance can be
performed on line
• Typically better performance
for a given SCA (f value)
• Typically more cost-effective
for a given gas volume
• Typically larger ESP for a
given gas flow
• Minimal sectionalization;
larger TR sets
• Internals are maintenance
intensive
• Most routine maintenance
performed off line Typically
Inferior performance for a
given SCA
• Typically less cost-effective
for a given gas volume
Tumbling Hammer TOP RAPPED
Improving ESP Performance
in a
SHORT TIME
a
Case History
The rebuilt Unit uses the same casing as the
existing ESP, but with internals converted from
tumbling hammer to top-rapped design. The
other design changes are:
Old New
3 Mechanical fields 6 mechanical fields
250 mm CE spacing 400 mm CE spacing
Conventional TR’s SMPS
Opacity 15-20% Opacity <<10%
Converting a Tumbling Hammer ESP to
Top-rapped Design - a case history
Pre Outage work to pre-assemble the roof
extension and penthouse
Penthouse
Ring/Roof
Girder
This shows that the unit was originally a tumbling
hammer design
Day 4
Starting to remove the old collecting electrodes
Day 7
Internals removal complete
Day 8
Lifting the pre-assembled ring/roof girder
Day 8
Lowering the pre-assembled
ring/roof girder onto the prepared flange
Day 12
Lifting a bundle of new Collecting electrodes
Day 12
Installing the new Collecting electrodes
Day 20
Starting to install the hot roof
Day 23
Cold roof installation complete
Day 24
Installing the CE rapper sleeves & shafts
Day 25
Rappers, T/R sets installed, LV wiring started
Day 27
Nighttime lifting of weather enclosure
Day 28
Weather enclosure in place - finish LV wiring
Day 29
Rebuild
complete
Ready for
Startup
Startup
Successful
After
4 week
outage
Contact Information
Charles Hayes
Regional Sales Director
SOUTHERNenvironmental,INC.
6690 West Nine Mile Road
Pensacola, Florida 32526
850-941-3001
chayes@sei-group.com
Renato Greco
New Technologies Development Manager
ENFIL
Renato.greco@enfil.com