Innovative environmentaltechnologies
ECONOMIC IN ECOLOGY
1958 Wet electrostatic precipitator for blastfurnace gas
1923 First large-size electrostatic precipitator for dust arresting in blast furnace gas
1924 Dry electrostatic precipitator for blastfurnace gas
Front: Fan cooler, capacity 200 m3/hRear: Countercurrent cooler, capacity 400 m3/h
System solutions for environmental protection
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● Ecological ● Economical ● Law-conforming ● Non-polluting
Those are features required of anindustrial production plant today.
The attempts of EWK EnvironmentalEngineering (Zschocke Environmental Engineering until 1968) to constructflue gas purification plants, which would meet these requirements, goback more than a century.
As early as 1914 Zschocke in Kaisers-lautern began to develop electrostaticprecipitators. The first large-size electro-static precipitation system worldwidewas completed in 1923.
As a competent provider of advancedfilter systems for the purification of air,water and soil we are a reliable partnerin all questions of environmental pro-tection.
We will continue to maintain this standard in the future: Through persis-tent research based on decades ofexperience in the industry and a comprehensive specialized know-how.
Based on decades of experience in the fields of dry and wet electrostaticprecipitators, wet absorbers, cycloneprecipitators and fabric filters, EWKUmwelttechnik began several yearsago to utilize its experience from individual industrial branches for newareas of application.Since information on emissions is oftenunavailable either in sufficient quantityor quality, and since the economic efficiency of a purification system is ofsignificance, various mobile trial plantsare available for practice-related tests.
Before the respective uses the trial plants can be adapted to the individualrequirement according to our experi-ence and calculations based on theavailable knowledge about the wastegas composition. This permits testingof the envisaged large scale solution inpractice. Optimization during the testperformance can further increase thedesigned precipitation capacity inalmost all processes.
Research and development Index
Moreover, the use of optimized trialplants often demonstrates that excel-lent results can be achieved especiallyby combining various plant systems.Testing in the preliminary stage of alarge scale plant, particularly in case of partially unknown or greatly varyingemissions, results in optimum econo-mic solutions.
Mobile trial scrubber,waste gas volume 2000-3000 m3/h.The system is set in a container frame andincludes complete electronic instrumentation,control and regulating (EMSR) technology,dosing station and waste gas fan.
Mobile trial wet absorber/ wet electrostaticprecipitation plant,waste gas volume 2000-3000 m3/h.This plant is equipped with complete EMSRtechnology and can be fitted with various wetabsorbers.
Mobile trail catalytic plant with catalytic sootfilter and DeNOx catalyzer,waste gas volume 500 Am3/h.The trial plant can be equipped with up to 3 rows of DeNOx - or oxidizer elements.
Dry electrostatic precipitators
Wet electrostatic precipitators
Fabric filters
Scrubbers
Catalytic waste gas purification
Water re-cooling plants
Sample applications
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Dry electrostatic precipitatorsDry type electrostatic precipitators aretoday considered the most economicalsystem for solving dust collecting pro-blems, as any dry dust generated canbe disposed of without any difficulty.
Proven technology in connection withhigh-grade materials ensures a longservice life and minimal maintenanceeffort for EWK electrostatic precipi-tators.We guarantee best quality and out-standing properties for every detail of our plants:
Safe and economical dry dust collection
● the bicoronary band electrode– uniform corona formation over
the entire length– welded into a tubular frame to
provide safety against breakage– no deflection towards the pre-
cipitation electrode
● the collecting electrode– dust collection spaces at both ends– exact plate guidance– high stability
● the transverse separators– for additional electric and mechani-
cal dust separation
● the rapping device– plate rapping by lifting and
disengagement of the first plate– discharge frame rapping by drop
hammers– all components enclosed in the
filter housing, no openings in the filter wall, prevention of corrosion damage
Charged gas molecule
Neutral gas molecule
ElectronDischarge electrode
gas flow direction
Current supply(high voltage)
Highvoltage
BICORONA electrodes, collecting electrodes and transverse separator
Physical separation process
Horizontal dry type electrostatic precipitator
Direction of gas flow
Dry electrostatic precipitator
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Current return(grounded)
Collecting electrode
Dust particle
charged collected
Dust collecting of cupola furnace waste gases
Discharge electrode rapping feature
Glass smelting pot dust arresting Smokestack heads of vertical vapor elec-trostatic precipitators downstream from lignite drying plant
Two-stage hot gas dry type electrostatic precipitator for glass smelting pot
Applications:
● Power station
● Wood and biomass combustion
● Waste and sludge combustion
● Glass smelting pots
● Coal and lignite drying systems
● Hot gas acid regeneration
● Cement, lime and gypsum industries
● Cupola furnaces
● Sintering plants and many more
Also in connection with noxious gasabsorption.
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Wet electrostatic precipitator Wet type electrostatic precipitators areused where aerosol-solid mixes have to be separated with high efficiency.Today wet type electrostatic precipita-tors with a high cost-benefit ratio areconsidered especially for separating:● aerosols● fine dusts● blue haze● paint mists● resin vapors● odours
Our plants are characterized by a number of outstanding properties:● high separation rate, clean gas solid
content up to 0,05 mg/m3
● optimum spray water input for satu-ration of gas and complete wetting of the separation area
● effective interval flushing of the separator and precipitator bottom
● complete pumping system for circulating water and waste water
● minimum consumption of fresh water● coating of internal walls and bottom
for corrosion protection; discharge and collecting electrodes or entire system of stainless steel or FRP, if required.
High efficiency by wet cleaning
Applications:
● Coking plants:coke oven process gas
● Mineral wool industry:forming plenum and curing oven waste gas
● Waste incineration:aerosol separationdownstream from wet scrubber
● Plastic and textile industry:aerosol and oil mist separation
● Chipboard industry:dryer and press exhaust air
● Meat smoking plants:smoke-chambre exhaust
● Smith industry:graphite-oil mist from forging press
● Varnishing plants:particle, aerosols from wet cabin
● Liquid waste incineration:aerosol separation after wet scrubber
Horizontal electrostatic precipitator for curingoven and forming plenum waste gases each 100,000 Am3/h
View into the separation area of a horizontalelectrostatic precipitator
Horizontal wet type electrostatic precipitator Vertical wet electrosaticprecipitator
Wet electrostatic precipitator
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For the high-voltage supply of ourelectrostatic precipitators we use high voltage d.c. supply systems with electronic controllers and thyristor regulators.Advantages: Short control periods,high efficiency, adaption to all serviceconditions, long service life.
Flash-over voltage
Voltage rise Rise
Automaticrun-up
Arc quenching timeRise
Voltage reduction
Typical control characteristics of a high voltage d.c. supply system
Vertical wet electrostatic precipitatorfor aerosol separation in the plastic industry
Vertical round type electrostatic precipitatorfor coke oven gas
Vertical wet electrostatic precipitator with closedabsorbent cycle and heat recovery system
BICORONA band electrode
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Fabric type filters Fabric type filters are an alternative toelectrostatic dust-collecting. In manyproduction areas, the manufacture ofthe products is connected with thedevelopment of environmentally hazar-dous materials and substances. Characteristics of such waste gasesare components of SO3, SO2, HCl and HF generated singly or often incombination with low until very high fine dust content and toxic matter too.
We are able to develop the appropriatefilter systems for the most varied areasof dry dust-arresting and material reco-very. We can react individually to yourdust-arresting problems with a varietyof filter designs in different dimensionsand various lengths and filter media.In many cases space and cost-savingfilter cartridges can be used instead of elaborate filter bags.
Optimum solutions for individual dust collecting problems
Cartridge filter for a sand blasting plant 40,000 m3/h
The EWK jet-pulse cleaningIt can be activated with the JP-tronicsystem either on time interval or on thedifferential pressure.Therefore a strongcompressed-air impulse of 0,1-0,3 sekis injected into the filter cartridge / filterbag. The cluster injector is supportingthe cleaning impulse. Through the puffup of the filter element with simulta-neous air-counter-flow the dust cake is cleaned of efficiently.
Advantages● Cleaning cycle and length of jet
impulse are adjustable in wide ranges● Continous cleaning or cleaning
depending on differential pressure is possible
● Cleaning on time interval if needed● Low compressed air consumption● Less wear
Fabric Filters
Applications:
● Furnaces and incinerators
● Glass, ceramic, building materialsindustry
● Foundries and smelting plants
● Cement and lime industry
● Metal working industry
● Rubber and plastic industry
● Iron works and steel mills
● Pulp and paper industry
● Waste management
● Galvanic industry
● Wood industry
● Chemical/pharmaceutical industry
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a) Filtering processSystematic representation of the filteringand cleaning process. During the filter-ing phase, the dust particles are separated on the outside of the filterelements in which the flow runs fromthe outside to the inside.
b) Bag cleaningThe filter elements are supplied withcompressed air at supersonic speed by aid of cluster injectors. Additionalsecondary air returned from the cleanair space provides for optimum flushingand cleaning of the filter elements. Thefilter elements can be reused for filteringafter cleaning.
The round filterwith corresponding bursting discs issuitable mainly for applications with a increased risk of explosion.
The round design enables an economi-cal construction with a high pressureresistance.
Bag filter with dry sorption in a termal powerplant with contaminated wood firing
Dry sorption
Conditioned dry sorption
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Dry sorption with the LÜHR condi-tioning rotor-recycle processBy admixture of additives like calcium-hydroxide Ca(OH)2 and/or activatedcharcoal into the gas stream, gaseousemissions, for example HF, HCI, Sox,Hg as well as PCDD/PCDF can bebound to the adsorbing agent and thencollected in the following bag filter.Thereby the conditioning rotor-recycleprocess has been proved as a reliablesystem with a high over-all efficiency.
Advantages● The process allows operation with a
high recycling rate of additives even if there are large amounts of proble-matic particles like CaCl2 in the gas stream.
● The conditioning rotor prevents the clog up of the recycled material and ensures a homogenous mixing of additives in the gas stream.
● Reliable observance of the required emission limits in the clean gas also in continous operation is ensured.
● A high utilization coefficient of the additives reduces the running costs.
Two passreactor
Conditioningrotor
Variabletransportrate
H2O
H2O
Additive
Compr. air
Particleoverflowdischarge
Additive
The oval bag filteris a fabric filter with horizontal placedfilter elements. It is suitable for offlinecleaning as well as for online cleaning.Ideal for applications with limited spacein height and area.
The in-line filteris often designed as a chamber filterwhich is preferred for offline cleaning.Thereby the individual chambers areisolated from the gas stream by flapsduring the cleaning cycle.
Environmental protection can also be conomical
Scrubber / heat recoveryAlthough scrubbers range among the simplest dust-arresters, they canbe used in a multitude of applications. They do not only serve as dust remo-vers, but are also used as gas coolers(quench), gas scrubbers for noxiousgas removal, or for liquid input of absorbent substances for bondingnoxious matter.
Because of today’s high requirementsin respect of the clean gas qualityand/or of the overall-energy-concept,scrubbers are often combined with:
A. Wet electrostatic precipitators (WESP)
Thereby the scrubber serves as quenchand pre-seperator for the WESP. Withthis system combination it is possibleto obtain a high separation-efficiencyof bigger then 99% even with a lowpressure loss.
Washer cooler with central nozzles withoutinternals
Possible uses of dust-arresters
Venturi scrubber with free overflow, roundconstruction
Scrubbers
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Applications:
● Waste incineration
● Thermal residual waste utilization
● Chemical industry
● Wood panel industry
● Paint/textile industry
● Wet desulphurization plants
● Plastic processing industry
● Food industry
● District heating power plant
B. Heat recovery systemWith integrated water/water or water/air heat-exchangers into the absorbentcycle of the scrubber it is possible totransfer large amounts of usable heatenergy from the exhaust air into awater cycle or air stream. It is oftenpossible to gain positive amortisation-calculations for the investment of awaste gas cleaning system.
The construction is always governedby their respective field of application.Possible examples are:● Washer-coolers without internal
installations ● Washer-towers with internal
installations ● Venturi washers with free overflow ● Venturi washers with adjustable
nozzle ● Venturi washers with adjustable
throat ● Combinations of various design
Clean gas
Tapered nozzles
Washer liquid
Sludge outlet
Raw gas
Raw gas
Size comparison
Visibility
Grain size range
Atmosph. aerosois
Application range of various gas cleaning systems
Cyclones
Wet type separators
Electrostatic precipitator
Fiber material and filter paper
Cloth filter
Rain Drizzlingrain Fog Haze-smoke
Dust from foundries
Metallurgical dust
Spores and pollens
Bacteria
Brown smoke
Alkalis, oxides
NH4 CI smoke
Grain diameterin microns µm
With the naked eye With microscope
50 µ 10 µ 1 µ
With ultra-microscope
Human hair
Clean gas
Outer ring jacket
Venturi neck edge
Venturi throat
Sludge outlet
Washer tower with internals Water/Water-heat exchanger
Water/Air-heat exchanger for pre-heating thecombustion air of a dryer,air-volume 80,000 m3/h,heat output 1,400 kW/h
WESP behind a wood chip dryer,volume 300,000 m3/h,diameter 9,950 mm
Vario-Venturi scrubber with infinitely variablenozzle with fluid treatment for purification ofexhaust gases from a non-ferrous smeltingfurnace
Wet Electrostatic Precipitator (WESP) behinda wood-chip dryer for the pellet productionwith a heat recovery system to feed into thedistrict heating network,exhaust gas volume 78,000 Am3/h,temperature 110 ˚C,diameter 5,700 mm,recovered heat energy 4-4.5 MW/h,water outlet temperature 68 ˚C,heat recovery rate 35-45%
Flue gas desulphurization plant with spraytower, 25,000 m3/h, 200 ˚C
Clog-proof washer pack built as gas distributor in combination with a wet type electrostatic precipitator
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Clean gas
Raw gas
Washer liquid
Dropletseparator
Packing material
Sludge outlet
CO
No
x
Dosing unit
Mixer
Reactor
PLC systemand dosing unit
Reaction solution Boiler
StackUrea
Catalytic technology for special solutions
Catalytic waste gas purificationCatalytic waste gas purification is one of the most important air purifi-cation technologies today.
The burning of biological fuels (wood,straw, biogas etc.) as well as of fossilfuels (oil, natural gas, heavy oil, coal)and industrial waste (solvent, sewagesludge, explosives, refuse and industrialresidue combustion etc.) generateslarge amounts of the following sub-stances even in the most advancedfurnaces:● Nitric oxide NOx● Carbon monoxide CO● Hydrocarbon CmHn● Dioxin/furan PCDD/PCDF
With the SCR catalyzer technologythese air pollutants can be separatedto a large degree and modified to N2,CO2 and H2O.
The degree of efficiency amounts to:● Nitric oxide 90-98%● Carbon monoxide 92-98%● Hydrocarbon 65-90%● Dioxin/furan 80-95%
The catalyzers we use are designed for a long service life of 20,000-40,000operating hours.Used catalyzers are taken back forreprocessing or disposal.
Modular constructionThe EWK reactors consist of modulesset in stainless steel casings.
First stageThe NOx conversion occurs in a re-duction catalyzer. The active materialis incorporated in ceramic honeycombelements.As reagent liquid urea solution orammonia water is used as well asammonia gas.
Second stageThe dioxin/furan conversion occurs in an oxidation catalyzer. The activematerial is incorporated in the ceramic element.
Third stageThe CO and CmHn conversion occursin an oxidation catalyzer. The ceramichoneycomb element is coated with anactive precious metal.
The individual stages are dimensionedaccording to the pollutant mix.This allows an individual optimization of each plant to achieve the most eco-nomical cost-benefit ratio.
Reaction diagram
NOX
H2OCO2
SO2
O2
CO
CmHn
NOX
Compressed air
Urea(NH2)2CO
H2OCO2
NH3
SO2
O2
CO
CmHn
NOxreduction
Catalytic waste gas purification
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Catalytic waste gas purification for oil (heavy, extra light) or gas furnace
Applications:
● Thermal power plants
● Waste incineration
● Acid pickling lines
● Waste wood incineration
● Explosives incineration
● Diesel engines
● Crematories
● Chemical/pharmaceutical industry
● Textile industry
● Thermal residual waste utilization
● Various process air purification systems
● Greenhouses
SCR catalyzer technologyis characterized by: ● Simple operation ● High operating safety● Low maintenance effort● Low operating costs● Wide temperature range 180-550 °C,
depending on pollutant● High conversion rate of up to 98% ● No additional emissions ● Low ammonia slip● Existing systems are easy to upgrade
Fibre filter catalyzerTo precipitate the micro dust (soot) from combustion engines fiber cart-ridge filters are used.Due to the catalytic coating of the fiberthe soot is oxidized at temperatures of360-480 °C.
Residual waste utilizationResidual waste utilization and processwaste gases often generate pollutantssuch as SO2, HCI, HF, Hg etc. At certaintemperatures chlorine and hydrocar-bon emissions lead to the formation ofdioxin/furan. These can be converted toharmless gases by suitable catalyzers.The separation of SO2, HCI, HF, Hgetc. can be performed by dry sorptionwith a downstream situated filter. Thiswill protect the catalyzers from prema-ture wear and guarantees compliancewith the pollutant limits.
Catalytic waste gas purification for thermal residual waste utilization DeNox unit for 2 diesel engines, 21,000 m3/h
Reaction diagram of a fiber filter catalyzer
H2OCO2
N2SO2
O2
CO
CmHn
H2OCO2
N2SO2
O2
CO + CmHnoxidation
De
NO
x
PLC system and dosing unit
Compressed air
Urea
De
NO
x
G Transport container
Sootfiltration
NOX
H2OC
SO2
O2
CO
CmHn
NOX
H2OCO2
SO2
O2
CO
CmHn
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SCR catalytic converter for engines DeNox system for glass melting process,21,000 m3/h
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MixerDosing unit
PLC systemand dosing unit
Reaction solution
Urea
Adsorption material
Dust
Boiler
Reactor
No
xP
CD
D/P
CD
F
CO
/HC
Stack
Heatexchanger
Sensible use of water as a raw material
Water re-cooling systemsThe plastic type small coolingtower series ZWK-W The use of high-performance axial flowfans makes the small cooling towers ofthe ZWK-W series particularly efficient.They are used in the dry cleaning in-dustry, for small air conditioning andrefrigeration units and wherever smallamounts of cooling water need to be cooled and the heat generated by industrial processes has to be discharged. The main elements of the ZWK-Wsmall cooling towers are made of glassfiber reinforced polyester and of PVCor PP.
Operating mode of the ZWK-W cooling towerIn the cooling tower the warm watertrickling down from nozzles is broughtinto close contact with the air ofambient temperature drawn in by thefan. The packing material of PVC or PP serves as a contact surface. Uponcontact with the air some of the watertrickling down evaporates and coolsoff. It is interesting to note that watercan be cooled down below the ambienttemperature.
The cooling depends primarily on thetemperature and relative humidity ofthe ambient air.
Depending on the location, the warmwater can be cooled down to approxi-mately 22-24 °C.The lower the desired water tempera-ture, the larger the cooling tower willhave to be.
Our economical, frequently provendesign concept offers high perform-ance and sturdy construction at considerable cost savings.
1 Casing2 Cold water tray3 Fan casing4 Warm water intake5 Cold water outlet6 Axial flow fan7 Drive motor8 Motor mounting
9 Tower packing10 Mist collector11 Spraying system12 Air intake louver13 Float valve14 Overflow socket15 Drain socket16 Strainer basket
Zschocke fan cooler,series ZWK-W 80 to 270,cooling capacity up to 0,843 MW/module.By connecting several modules the coolingcapacity can be expanded as required.
Water re-cooling plants
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System combinations
The increased legal and technicalrequirements on a waste gas cleaningsystem often lead to a system combi-nation of different waste gas treatmentsteps. While a simple scrubber mayhave been sufficient formerly, a combi-nation of multistage scrubber, wet ESPand waste water treatment with heatrecovery system is often required to-day. In other cases multicyclones haveto be replaced or complemented bydry sorption with bag filter and DeNoxunits.
With the selection of the most suitabletreatment system it is of great impor-tance to find an optimum solution withrespect to economical and ecologicalconsiderations. For budgetting theoperation cost are often more impor-tant than the investment costs.
Two-stage WESP system behind forgingpress with integrated ultra-filtration for recyclable material
DeNox catalytic system for glass smelter; 2 x 152,300 m3/h
2 lines with a two-stage WESP each withspecial FRP casing and high degree stainlesssteel internals behind liquid waste incinerati-on, quench and scubber,volume each 37,000 Am3/h,efficiency > 99,5%
Waste gas cleaning system for 2 OSB-dryerSystem combination of quench,wet scrubber,dual wet electrostatic precipitator with stackup to 60 m
Mineral coal heating plant, combined installation system comprising exhaust gasheat recovery, flue dust collection and wet desulphurization
Wet electrostatic precipitator with biologicalwater treatment system
Sample applications
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Environmental protection is a traditionat EWK Environmental Engineering.Our plants, proven throughout theworld in decades of operation, are thebest evidence.
With this experience we develop andoffer innovative technologies.
● Plant design
● Engineering
● Production
● Assembly
● Commissioning
● Maintenance/service
for:
■ Electrostatic precipitators
■ Fabric type filters
■ Wet absorber/scrubbers
■ Catalytic gas cleaning systems
■ Heat recovery systems
■ Water cooling towers
■ System combinations
EWK Anlagentechnik AGFrauenfelderstr. 21aCH-8404 WinterthurTelefon +41 (0)52/2 45 19 19Telefax +41 (0)52/2 45 19 10 E-Mail: [email protected]
Walter SondereggerKlosters/PanyTelefon +41 (0)81/4 22 54 53Telefax +41 (0)81/4 22 54 63E-Mail: [email protected]
PRO. TECGiussano (Mi)Telefon +39 0362/85 29 11Telefax +39 0362/85 37 61E-Mail: [email protected]
Bo-E. SjöbergTelefon +46 (0)36/16 76 00Telefax +46 (0)36/17 64 41E-Mail: [email protected]
Hartmut OrthTelefon +61 (0)3/9596 75 77Telefax +61 (0)3/9596 66 94E-Mail: [email protected]
Mason Engineers Ltd.Telefon +64 (0)9/274 3143Telefax +64 (0)9/274 3145E-Mail: [email protected]
J. B. OchelskyTelefon +48 (0)22/6 21 18 91Telefax +48 (0)22/6 28 03 25E-Mail: [email protected]
ATC KOREA CO., LTD.Telefon +82 (0)2/783 - 6855Telefax +82 (0)2/783 - 6854E-Mail: [email protected]
Subsidiaries
RepresentativesSWITZERLAND
ITALY
Branch officesSWEDEN
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NEW ZEALAND
POLAND
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EWK Umwelttechnik GmbHBarbarossastrasse 30D-67655 KaiserslauternTelefon +49 (0)631/3577-0Telefax +49 (0)631/3577-111Internet: www.ewk.deE-Mail: [email protected]