Particles & dust
Mass loading, particle size, temperature, abrasive, sticky or hygroscopic behaviour and any material value associated with captured dust.
COOLING • NEUTRALISATION • FILTRATION
Industrial flue-gas treatment & filtration, designed around the pollutants actually present.
CFI Systems designs and integrates flue-gas treatment systems for furnaces, incinerators and industrial thermal processes. Technology selection depends on gas flow, temperature, dust loading, acid gases, metals, organic compounds and the site's emissions requirements.
The line is engineered as one system: gas cooling, reagents, filtration, extraction, instrumentation, emissions analysis, automation and interfaces with the upstream thermal process.
Baghouse • Ceramic
Scrubber • Venturi • WESP
New build • Retrofit
From furnace to stack
01Flue-gas characterisation
02Cooling & conditioning
03Neutralisation / adsorption
04Filtration & extraction
05Emissions monitoring & control
Controlled temperatureCondition the gas for treatment and protect the filter media
Target pollutantsDust, HCl, HF, SO₂, metals, organics and other species according to the process
Controlled negative pressureExtraction sized for pressure losses across the complete line
Monitored performancePressures, temperatures, reagents, emissions and system status logged
Characterisation
Start with the real flue gas, not with a catalogue filter.
Two installations with the same thermal duty may require very different treatment systems depending on the material processed, temperature, chlorine or sulphur content, dust loading, metals and process dynamics.
Sizing therefore starts with gas flow, temperature, composition, dust, peak loads, normal and transient operation, together with the emissions limits applicable to the site.
HCl, HF, SO₂ & other acid gases
Neutralising reagent, stoichiometry, reaction temperature, contact time and dosing strategy are selected according to measured or estimated concentrations.
Heavy metals & volatile compounds
Condensation, adsorption and capture mechanisms are assessed. Depending on the process, dry filtration, wet scrubbing or a WESP polishing stage can be considered for fines, aerosols and certain metals.
Dioxins, furans & organic compounds
Controlled gas cooling, adsorption on a suitable sorbent and optimisation of upstream combustion/afterburning.
Nitrogen oxides & DeNOx
Reduction first through process and combustion control, followed by SNCR or SCR DeNOx where the emissions target requires it.
CO, VOC & unburned species
These are primarily controlled by good combustion and suitable afterburning; a filtration system cannot compensate for poor upstream thermal treatment.
Treatment architecture
Cool, react, filter and extract within the correct operating window.
Dry and wet treatment performance depends strongly on temperature, humidity, contact time and pressure drop. Each item is therefore sized together with the next.
CFI Systems coordinates the complete line to avoid common mismatches: gas too hot for the filter, reagent injected outside its effective range, insufficient extraction capacity or condensation in ductwork.
ConditioningCooling, dilution, humidification or heat recovery depending on the selected architecture.
ReactionReagent injection and mixing with contact time suited to the target pollutants.
SeparationCapture of particles and reaction products on filter media or in a wet separation stage.
ExtractionFan sized for total system pressure loss to maintain process negative pressure.
Treatment technologies
Dry filtration, ceramic filtration or wet scrubbing: select the architecture around the gas.
CFI Systems can integrate different treatment families depending on temperature, flow, dust type, acid gases, metals, available footprint and target performance. Several technologies can be combined on the same line.
1
Textile baghouse filter
Dirty-gas / clean-gas housing with textile bags on cages, dust hoppers and automatic pulse-jet cleaning using compressed air. A robust dry-filtration solution after suitable gas cooling.
2
High-temperature ceramic filtration
Rigid ceramic elements or candles capable of operating above the temperature range of conventional textile media, with pneumatic cleaning and the possibility of combining particulate capture, sorbents and catalytic functions depending on the technology selected.
3
Dry & semi-dry treatment
Injection of lime, sodium bicarbonate, activated carbon or other sorbents, with reaction in the duct or in a dedicated reactor before final separation.
4
Wet scrubbers
Gas cooling and washing through gas/liquid contact, with recirculation, pH control, mist elimination and blowdown management according to the target pollutants.
5
Venturi & high-energy scrubbing
Gas acceleration and liquid atomisation create intense gas/droplet contact, particularly useful for particulate capture and conditioning of certain flue gases.
6
WESP / wet electrostatic precipitation
Optional polishing stage after cooling or wet scrubbing to capture submicron particles, mists, aerosols and certain metals using an electrostatic field with washed collecting surfaces.
Flue-gas cooling
Bring the gas to the right temperature before reagent injection and filtration.
Cooling directly affects neutralisation chemistry, condensation of certain compounds, filter-media lifetime and the overall energy efficiency of the installation.
Depending on the project, CFI Systems can integrate a water-tube heat exchanger, smoke-tube heat exchanger, dilution, quench or another suitable conditioning solution.
01Water-tube heat exchanger
02Smoke-tube / fire-tube heat exchanger
03Quench or evaporative cooling where appropriate
04Bypass, temperature safety and filter protection
05Heat recovery integrated where justified by the energy balance
Reagents & adsorption
Inject the right amount, at the right point and at the right temperature.
Reagent consumption depends on pollutant concentration, temperature, mixing, stoichiometry and contact time. Permanent overdosing increases cost and residues; underdosing compromises performance.
CFI Systems sizes storage, extraction, dosing, pneumatic or mechanical conveying, injection point, mixing and control according to the treatment line.
Hydrated limeNeutralisation of many acid gases within a temperature range suited to the process.
Sodium bicarbonateAlternative neutralisation route assessed according to pollutants, temperature, consumption and residue management.
Activated carbon / adsorbentsCapture of organic compounds, dioxins/furans and certain volatile metals depending on the application.
Controlled dosingInjection can be adjusted to process or emissions measurements where instrumentation and process dynamics make this relevant.
NOx reduction
Select SNCR or SCR according to temperature window, required reduction and line architecture.
NOx formation should first be limited at source through combustion and process control. Where this is not sufficient, a dedicated DeNOx stage can be integrated into the flue-gas line.
The choice between SNCR and SCR depends on the required reduction level, available temperature, process stability, ammonia slip risk and the overall layout of the installation.
SNCRSelective non-catalytic reduction using injection of a suitable reagent within the temperature window required for the reaction.
SCRSelective catalytic reduction where the required performance or operating context justifies a dedicated catalytic stage.
ReagentsUrea or ammonia / aqueous ammonia solutions can be studied according to process, safety and site operating requirements.
IntegrationThe DeNOx solution is coordinated with gas temperature, dust, conditioning, filtration and emissions analysis.
Dry filtration
Two main architectures: textile bags or ceramic elements.
Media selection depends primarily on gas temperature, chemistry, spark risk, dust properties, injected reagents, filtration velocity and maintenance requirements.
Textile baghouse filter
Dirty-gas / clean-gas architecture with filter bags supported by cages. Dust and neutralisation products are retained on the surface of the media.
Compressed-air cleaning
Short reverse air pulses triggered by sequence or differential pressure remove the dust cake and drop it into the hoppers.
Ceramic candles / rigid elements
Microporous rigid media suited to hotter gases and applications where thermal resistance, spark resistance or compact high-temperature filtration is important.
Reactive cake & sorbents
On a dry system, deposited reagent and dust continue neutralisation and adsorption reactions on the media before cleaning.
Ash & residue removal
Hoppers, screws, rotary valves, big-bags or other systems remove dust and spent reagents while limiting fugitive dust and air ingress.
ΔP, temperature & protection
Differential pressure, inlet temperature, cleaning status and residue levels are monitored to protect the media and maintain stable operation.
The media is never selected in isolation: upstream cooling, reagents, dust characteristics and extraction fan together determine the real performance of the filter.
Wet treatment
Scrubbers, Venturi, absorbers and wet precipitation according to the pollutants to be treated.
Wet treatment can be used to rapidly cool flue gas, capture particles, absorb soluble gases or provide a high-efficiency polishing stage. In return, water, reagents, corrosion and liquid effluents must be managed as part of the system.
Spray scrubber
Flue gas passes through a washing zone where spray nozzles create gas/liquid contact to cool the stream and capture particles or soluble pollutants.
Counter-current scrubbing
Gas can move upward while liquid is sprayed downward, increasing contact between flue gas and washing solution.
Venturi scrubber
Gas is accelerated through a Venturi throat where liquid is strongly atomised. The intense contact supports particulate capture where higher scrubbing energy is required.
Packed-bed scrubber / absorber
High gas/liquid contact area improves absorption of selected acid gases or soluble compounds, with pH control and chemistry adapted to the application.
Wet electrostatic precipitator
A WESP can be installed after wet scrubbing to capture residual submicron particles, aerosols and mists. Collecting surfaces are washed to remove captured contaminants.
Recirculation & effluents
Pumps, sump, liquid filtration, chemical dosing, pH/conductivity control, blowdown and effluent treatment are integral parts of the wet system.
Extraction & negative pressure
The fan must see the whole line, not only the stack.
Every heat exchanger, duct, reactor, filter or scrubber adds pressure loss. The induced-draft fan is sized for the complete operating point so that the furnace remains under the required negative pressure while retaining a reasonable operating margin.
Control can use furnace pressure, filter differential pressure and fan speed to follow fouling and flow variations.
01Pressure-loss calculation across the complete line
02Extraction fan sized at the real operating point
03Variable speed according to negative pressure and process conditions
04Bypasses and degraded modes where required for safety
05Noise, vibration and maintenance access integrated into the design
Retrofit of existing flue-gas lines
Modernise a treatment system without necessarily replacing the complete line.
Poor performance may be caused by undersized equipment, but also by a fouled heat exchanger, poor reagent dosing, ageing bags, air ingress, an extraction fan operating off its duty point or unsuitable control logic.
Measurements & diagnosis
Temperatures, flows, pressures, pressure loss, analysis, reagent consumption and equipment inspection.
Heat exchanger or quench
Cleaning, repair, replacement or resizing of the cooling stage to restore the correct treatment window.
Dosing & injection
Modernisation of hoppers, screws, feeders, conveying, injection point and control strategy.
Bags, candles & cleaning
Replacement of textile bags or ceramic elements, improved sealing, pulse-jet cleaning, sequencing and residue removal.
Fan & draft
Recalculation of the network, fan modification, variable-speed control and furnace-pressure regulation.
Automation & analysis
PLC migration, new sensors, analysers, data logging and diagnostics to improve reliability of operation.
Emissions analysis & instrumentation
Measure the system in order to control it and demonstrate performance.
Emissions monitoring is defined according to the process and the requirements applicable to the site. Regulatory measurements and process-control measurements are not always the same.
CFI Systems integrates the interfaces between analysers, PLC and supervision so that data can be used for emissions follow-up, reagent dosing, diagnostics and historical records.
Process measurementsTemperatures, pressures, O₂, flows, differential pressure, levels and reagent consumption.
Gas analysisIntegration of analysers required according to the installation type and site obligations.
Data loggingTrends, alarms, exceedances, consumption and operating data required for follow-up.
MaintenanceDiagnostics, calibration, sensor drift and equipment status integrated into supervision.
Complete integration
From thermal process to stack, one operating logic.
Filtration performance depends directly on what happens in the furnace. CFI Systems therefore coordinates combustion, afterburning, cooling, filtration, extraction and emissions analysis within one control strategy.
1
Furnace / process
Flow, temperature, O₂, cycle phases and load variations communicated to the flue-gas line.
2
Conditioning
Cooling to the temperature required for reactions and filter-media protection.
3
Reagents
Dosing and injection controlled according to recipe, load or available measurements.
4
Filtration
Management of differential pressure, cleaning and residue removal.
5
Extraction
Maintain draft and furnace negative pressure despite changes in system pressure loss.
6
Analysis
Follow emissions and process variables with alarms, history and operating reports.
Performance & operating cost
Meet emissions targets without wasting reagents, energy or consumables.
A good treatment line must perform across its full operating range, not only during a one-off test. Availability, reagent consumption, fan power and filter-media life strongly influence total operating cost.
CFI Systems includes these factors in the design and can track operating indicators after commissioning to optimise settings.
01Emissions and stability of measured values
02Specific reagent consumption
03Differential pressure and extraction energy
04Lifetime of bags, ceramic candles and cleaning equipment
05Quantity of residues generated and ease of maintenance
Project method
Size the treatment line from the flue-gas balance and emissions objectives.
Flue-gas treatment is an interdependent chain. Defining the filter alone is not enough: flow, temperature, pollutants, cooling, reagents, extraction and transient operation must be studied together.
1
Characterise
Flows, temperatures, dust, pollutants, humidity and process variability.
2
Define objectives
Emissions values, availability, consumables, maintenance and layout constraints.
3
Select architecture
Dry, semi-dry, wet, filter media, gas cooling, reagents and DeNOx where required.
4
Size equipment
Heat exchangers, reactors, filters, fans, ducts, reagent storage and residue handling.
5
Automate
Sensors, controls, filter cleaning, dosing, emissions analysis and supervision integrated into the line.
6
Commission
Testing, tuning, consumption optimisation, training and performance follow-up.
CFI Systems approach
Treat flue gas as part of the thermal process, not as equipment added at the end of the line.
The best filter cannot correct unstable combustion, poorly controlled gas temperature or an undersized extraction fan. CFI Systems works on these interfaces to create a coherent process from furnace to stack.
The right filter starts with the right flue gas.
Temperature, flow, chemistry, dust, reagents and draft must remain within a controlled operating window.
01 · CHARACTERISE
Know the gas
Flow, temperature and composition define the relevant technologies.
02 · CONDITION
Create the right window
Cooling and humidity matched to the reactions and filter media.
03 · CAPTURE
Treat the pollutants
Reagents, adsorption, filtration or wet scrubbing selected according to the species present.
04 · CONTROL
Maintain performance
Pressure, dosing, extraction and analysis controlled continuously.
Frequently asked questions
Industrial flue-gas treatment & filtration.
The right treatment line depends on the process, pollutants, gas flow, temperature and requirements applicable to the site.
What is the difference between dry and wet flue-gas treatment?
Dry treatment generally uses powdered reagents followed by filtration to neutralise and capture pollutants. Wet treatment transfers selected pollutants into a liquid phase and therefore requires management of blowdown and liquid effluents.
What is the difference between a spray scrubber, Venturi scrubber and WESP?
A spray scrubber mainly provides cooling, washing and absorption through gas/liquid contact. A Venturi adds higher energy to the gas/droplet contact for improved particulate capture. A WESP uses a wet electrostatic field to capture residual submicron particles, aerosols or mists and is often used as a polishing stage.
Why cool flue gas before filtration?
Cooling brings the gas into a temperature range compatible with the filter media and neutralisation chemistry. It can also enable useful heat recovery before final treatment.
When should a textile baghouse or ceramic filter be selected?
A textile baghouse is a proven solution where the flue-gas temperature is compatible with the media. Ceramic elements become attractive where temperature is higher, spark resistance is important or compact high-temperature filtration is required.
What is a pulse-jet baghouse filter?
It is a bag filter in which dirty gas enters the raw-gas side, passes through the filter bags and exits on the clean-gas side. Short pulses of compressed air periodically clean the bags and drop the dust cake into the hoppers.
Which reagents can be used for acid-gas neutralisation?
Depending on pollutants and temperature, reagents such as hydrated lime or sodium bicarbonate can be considered. Selection must take account of efficiency, dosage, residue generation and operating cost.
What is activated carbon used for?
It can be used as an adsorbent for selected organic compounds, dioxins/furans and volatile metals. Its use depends on the real composition of the flue gas.
Can CFI Systems integrate a DeNOx system?
Yes where NOx emissions and the project framework require it. Depending on reduction target and available temperature, CFI Systems can study SNCR or SCR. The first step remains optimisation of combustion and the thermal process to avoid unnecessary NOx formation.
What is the difference between SNCR and SCR?
SNCR is selective non-catalytic reduction using reagent injection within a suitable temperature window. SCR uses selective catalytic reduction and can be selected where the required reduction efficiency, process stability or operating context justify a dedicated catalytic stage.
Why is filter differential pressure important?
It indicates the loading state of the media and dust cake. A value that is too low or too high can indicate problems with cleaning, media condition, leakage or operating conditions.
Can an old filtration line be modernised?
Yes. An audit may show that only the heat exchanger, reagent system, filter media, extraction fan, automation or emissions analysis needs to be replaced rather than rebuilding the complete line.
Can CFI Systems replace a heat exchanger upstream of the filter?
Yes. Replacement can involve a water-tube or smoke-tube / fire-tube exchanger, resized according to gas flow, temperature, heat-recovery duty and the temperature required at the inlet of the treatment system.
How is the extraction fan selected?
It must be sized for the gas flow and total pressure loss of the complete line, with suitable margin for fouling and for maintaining the required furnace negative pressure.
Which processes can use a CFI Systems flue-gas line?
Cremation, medical or industrial waste incineration, thermal cleaning, pyrolysis, precious-metal recovery and other thermal processes requiring controlled flue-gas treatment.
CFI Systems
Flue-gas treatment integrates with all our thermal-process solutions.
CFI Systems combines filtration and emissions control with cremation systems, incineration systems, thermal cleaning & paint stripping ovens, pyrolysis furnaces, precious metal recovery furnaces and retrofit & modernisation projects.
Explore all our solutions
Flue-gas treatment project
Tell us about your process, flue gas and emissions targets.
New line, textile baghouse, high-temperature ceramic filtration, dry treatment, wet scrubber, Venturi, WESP, reagents, heat exchanger, SNCR or SCR DeNOx, emissions analysis or retrofit: CFI Systems studies the complete treatment chain.
contact@cfi-systems.com
Centre d’Affaires Giennois – Bureau B9 · 1 rue Antoine de Lavoisier · 45500 Gien · France
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