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SO2 Scrubber for Industrial Sulphur Oxide Emission Control
Envigaurd’s SO2 Scrubber is a counter-flow wet absorption system designed to remove sulphur dioxide (SO2) and sulphur oxides (SOx) from industrial exhaust streams. Built with a polypropylene (PP) shell and FRP outer reinforcement, the unit houses PP Pall ring or structured packing, a PP/FRP sump, and SS 316 or PP recirculation pumps – engineered for long-term corrosion resistance in aggressive flue gas environments. With over a decade of in-house design and manufacturing experience, Envigaurd delivers scrubbers that meet your plant’s compliance and performance requirements.
CPCB Compliant Design
10+ Years in Emission Control
In-House Manufacture & QC
Pan-India Installation
CPCB Compliant Design
10+ Years in Emission Control
In-House Manufacture & QC
Pan-India Installation
Envigaurd at a Glance
50+
SO2 Scrubber Systems Installed
Deployed across chemical, thermal, and process plants throughout India.
10+
Years of Emission Control Experience
A decade of application-specific engineering for SO2 and SOx treatment.
40+
Industrial Clients Served
From small captive power plants to large sulphuric acid and smelter facilities.
18+
States with Active Installations
Pan-India project execution with a dedicated commissioning team.
99%+
SO2 Removal Efficiency Achieved
Consistently meeting CPCB SO2 norms of ≤200 mg/Nm³ for general industries.
4-8 Wks
Average Commissioning Time
From order confirmation to a fully operational scrubber at your plant site.
What Is an SO2 Scrubber?
An SO2 Scrubber is a counter-flow wet absorption system in which contaminated flue gas rises through a packed bed tower while an alkaline scrubbing liquor – typically sodium hydroxide (NaOH) or sodium carbonate (Na2CO3) solution – flows downward. SO2 reacts with the alkali to form sodium sulphate and sodium sulphite, effectively neutralising the acid gas before it reaches the atmosphere. As a proven industrial air pollution scrubber, this technology is central to any chemical plant SO2 treatment programme and is the foundation of a compliant sulfur emission treatment unit across diverse industrial sectors.
Sulphur dioxide is a corrosive, reactive gas that irritates the respiratory tract, damages vegetation, and reacts with atmospheric moisture to form sulphuric acid – making it an acid rain precursor gas control priority for regulators worldwide. Under India’s Environment Protection Act and CPCB SO2 emission norms, general industries must maintain stack SO2 concentrations at or below 200 mg/Nm³. Non-compliance attracts plant shutdowns, financial penalties, and reputational damage. An effective SO2 removal system is therefore a legal and operational necessity for any plant burning sulphur-containing fuels or handling sulphur-rich raw materials.
Envigaurd’s SO2 Scrubber is designed and manufactured in-house at our facility. The tower shell is fabricated from polypropylene (PP) for chemical resistance, with fibreglass-reinforced plastic (FRP) outer reinforcement to handle mechanical and thermal loads. Inside, PP Pall ring random packing or structured packing maximises gas-liquid contact area. The PP/FRP sump collects and recirculates the scrubbing liquor via SS 316 or PP recirculation pumps, selected based on liquor chemistry. A pH-controlled dosing system maintains the alkali concentration required for consistent SO2 absorption performance.
Plants that install Envigaurd’s SO2 Scrubber achieve stack emissions well within regulatory limits, improve workplace air quality, and reduce the risk of corrosion damage to downstream equipment. The modular design integrates into existing exhaust systems with minimal civil work, and our optional two-stage configuration delivers additional removal efficiency where inlet SO2 concentrations are high. Contact Envigaurd to discuss the right configuration for your specific process exhaust.
Technical Specifications
| Parameter | Typical Value / Range |
|---|---|
| Scrubber Type | Counter-flow packed bed wet scrubber |
| Shell Material | Polypropylene (PP) with FRP outer reinforcement |
| Packing Type | PP Pall ring (random) or PP structured packing |
| Sump Material | PP or FRP |
| Recirculation Pump Material | SS 316 or PP (application-specific) |
| Gas Flow Rate | 500 Nm³/hr to 100,000 Nm³/hr (custom designs available) |
| Liquid-to-Gas (L:G) Ratio | 2–5 L/Nm³ (optimised per inlet SO₂ concentration) |
| Pressure Drop Across Packing | 15–50 mm WC (design-specific) |
| SO₂ Removal Efficiency | Up to 99%+ single-stage; >99.5% two-stage |
| Inlet SO₂ Concentration Range | 100 ppm to 5,000 ppm |
| Operating Temperature | Up to 80°C (PP shell); higher with FRP lining options |
| Scrubbing Reagent | NaOH (10–15% w/w) or Na₂CO₃ solution |
| pH Control Range | 7.0–10.5 (automated pH dosing system) |
| Flange Standard | IS 1538 / ANSI 150# (as specified) |
| Installation Type | Vertical tower - skid-mounted or civil foundation |
≥99%
SO2 removal up to 99%+ in single-stage and >99.5% in two-stage configuration.
100ppm - 5,000 ppm
Handles variable inlet concentrations from 100 ppm to 5,000 ppm without system redesign.
PH-Controlled
pH-controlled recirculation ensures continuous alkalinity and consistent absorption efficiency.
Key Features of Enviguard's HCl Scrubber
Every design decision in Enviguard’s hydrogen chloride scrubber reflects 10+ years of field experience with corrosive gas handling..
Full Corrosion Resistance
PP shell, FRP reinforcement, and PP/SS 316 internals resist sulphuric acid, alkali solutions, and high-humidity flue gas throughout the equipment service life.
High-Efficiency Packed Bed
PP Pall ring or structured packing delivers maximum gas-liquid interfacial area, ensuring thorough SO2 absorption across varying gas velocities and loads.
Wide Concentration Range (100–5,000 ppm)
Handles inlet SO2 concentrations from 100 ppm to 5,000 ppm in a single unit - no pre-dilution or bypass required for most industrial applications.
pH-Controlled Reagent Recirculation:
Automated pH monitoring and NaOH/Na2CO3 dosing maintain optimum scrubbing liquor alkalinity, minimising reagent wastage and maximising SO2 capture.
Skid-Mounted Option Available
Pre-assembled skid units with pump, instrumentation, and piping reduce on-site installation time and eliminate the need for large civil foundations.
Low Pressure Drop Design
Packing selection and tower geometry are optimised to limit system pressure drop to 15-50 mm WC, protecting your ID fan and reducing auxiliary power consumption.
Integrated Mist Eliminator
A chevron or mesh-pad mist eliminator installed at the tower outlet prevents liquid carryover into downstream ducts, fans, and stack lining.
Easy Maintenance Access
Inspection hatches, drain connections, and removable packing sections allow routine checks and packing replacement without confined-space entry.
Optional Two-Stage Configuration
Where extremely low outlet SO2 concentrations are required, Envigaurd offers a two-stage scrubber with independent recirculation loops for each stage.
Instrumentation & Controls Ready
Pressure taps, temperature sensors, pH probes, and flow meters are pre-fitted, enabling seamless integration with your plant DCS or standalone PLC panel.
Benefits of Installing an Envigaurd SO2 Scrubber
Regulatory Compliance - Guaranteed
Envigaurd’s SO2 Scrubber is sized and designed to maintain stack SO2 concentrations at or below 200 mg/Nm³ as mandated by CPCB SO2 emission norms for general industries under the Environment Protection Act. Avoid shutdown notices and consent-to-operate cancellations that cost your plant time and revenue.
Improved Worker Safety
Reducing SO2 at source protects workers in and around the plant from respiratory irritation, chemical burns, and long-term pulmonary health damage associated with chronic sulphur oxide exposure – directly reducing your EHS incident rate.
Uninterrupted Plant Operations
A properly sized scrubber prevents corrosion of ductwork, fans, and stack liners caused by untreated SO2-laden gas – extending equipment life and avoiding costly unplanned maintenance shutdowns.
Low Total Cost of Ownership
Corrosion-resistant PP/FRP construction, low pressure drop design, and efficient reagent recirculation minimise energy, chemical, and maintenance expenditure throughout the scrubber’s 15+ year service life.
Fast Commissioning - 4 to 8 Weeks
Envigaurd’s in-house design, fabrication, and commissioning team delivers fully operational scrubber systems within 4 to 8 weeks from order confirmation, minimising the period of regulatory exposure.
Positive Environmental Footprint
Capturing sulphur dioxide prevents acid rain formation, protects surrounding vegetation and waterways, and demonstrates corporate environmental responsibility to customers, regulators, and investors.
Handles Process Variability
The wide inlet range (100-5,000 ppm) and adjustable L:G ratio allow the scrubber to adapt to seasonal fuel quality variations and process upsets without compromising outlet SO2 compliance.
Dedicated After-Sales Support
Envigaurd’s AMC programmes, remote diagnostics, and on-site service teams ensure your SO2 scrubber performs to specification throughout its operational life – not just at commissioning.
Working Principle of the SO2 Scrubber
Technology Overview
Envigaurd’s SO2 Scrubber operates on counter-flow wet absorption. Contaminated gas enters the tower at the base and rises through a packed bed – PP Pall ring or structured packing – while an alkaline scrubbing liquor descends from spray nozzles at the top. The intimate gas-liquid contact across the high-surface-area packing enables SO2 to transfer from the gas phase into the liquid phase, where it reacts with NaOH or Na2CO3 to form sodium sulphate and sodium sulphite. This reaction neutralises the primary contaminant of the sulfur emission treatment unit and prevents acid rain precursor gas control failures that result from untreated SO2 discharge. Spent liquor drains to the sump for pH correction and recirculation, while clean gas exits through the mist eliminator to atmosphere or downstream process equipment.
SO2 + 2NaOH → Na2SO3 + H2O
Step-by-Step Process
1
Flue gas containing SO2 (100-5,000 ppm) enters the scrubber tower at the base inlet nozzle.
2
A pre-quench section (where fitted) cools excessively hot gas and pre-saturates it before packing entry.
3
Gas distributes evenly across the tower cross-section via an inlet gas distributor baffle or distribution plate.
4
Gas rises counter-currently through PP Pall ring or structured packing at a controlled face velocity of 1.5-2.5 m/s.
5
Alkaline scrubbing liquor (NaOH or Na2CO3 solution) is pumped from the sump and sprayed over the packing from liquid distributor nozzles at the top.
6
SO2 absorbs into the liquid film on the packing surface: SO2 + 2NaOH → Na2SO3 + H2O (further oxidised to Na2SO4 with excess oxygen).
7
Spent liquor containing sodium sulphite and sulphate drains by gravity to the PP/FRP sump below the packing.
8
A pH sensor in the sump monitors alkalinity continuously; the automated dosing system injects fresh reagent to maintain pH between 7.0 and 10.5.
9
Treated gas exits the packing and passes through a chevron or mesh-pad mist eliminator to strip entrained liquid droplets.
10
Clean gas – with SO2 reduced to ≤200 mg/Nm³ or better – exits the tower outlet nozzle and is discharged to the stack.
Industries We Serve
Sulphuric Acid Plants
Tail gas streams from sulphuric acid converters contain residual SO2 that can exceed regulatory limits significantly. Envigaurd's SO2 removal system for industrial processes captures tail gas SO2, ensuring your plant meets CPCB norms without interrupting sulphuric acid production.
Boiler Flue Gas Treatment
Coal- and oil-fired boilers generate SO2-laden flue gas in direct proportion to fuel sulphur content. Envigaurd's SO2 scrubber for boiler exhaust integrates with your existing chimney or ducting, bringing stack emissions below 200 mg/Nm³.
Thermal Power Captive Plants
Captive thermal power stations burning high-sulphur coal require a reliable flue gas desulfurization system. Envigaurd delivers skid-mounted or civil-foundation FGD units sized for your generator capacity and consent conditions.
Rubber Processing
Vulcanisation and rubber processing release sulphur dioxide as a by-product. Our caustic scrubber for SO2 neutralises these emissions, protecting plant ambient air quality and supporting your EHS compliance programme.
Ore Smelters
Smelting of sulphide ores - copper, lead, zinc - produces high-volume, high-concentration SO2 off-gas. Envigaurd's sulphur oxide emission control system handles the demanding flow rates and concentrations typical of primary smelter operations.
Dye & Pigment Manufacturing
Reduction and sulphonation reactions in dye manufacture release SO2 and acid gases. Our wet scrubber for SO2 gas provides reliable, continuous treatment aligned with chemical plant SO2 treatment best practice.
Chemical Process Industries (CPI)
Batch and continuous processes involving sulphur chemistry produce variable SO2 loads. Envigaurd's pH-controlled recirculation accommodates load fluctuations, maintaining stable outlet SO2 concentrations throughout your production cycle.
Fertiliser Plants
Phosphoric acid and NPK production involves sulphur chemistry that can release SO2. As a specialist SOx scrubber manufacturer India clients trust, Envigaurd sizes and designs for fertiliser plant emission points of all scales.
Petroleum Refineries
FCC regenerator and Claus unit tail gas streams contain SO2 that must be controlled before stack discharge. Envigaurd's sulfur dioxide scrubber systems are designed for the flow rates and temperatures typical of refinery applications. Don't see your industry? Contact Envigaurd - we assess every application on its specific gas composition, flow rate, and regulatory requirement.
Typical Application Scenarios
Coal-Fired Captive Boiler
Compliance Upgrade
Challenge
A 15 MW captive power plant burning high-sulphur coal was recording stack SO2 levels of 850-1,200 mg/Nm³, far exceeding the CPCB limit, and faced consent-to-operate renewal rejection.
Solution
Envigaurd designed and supplied a single-stage packed bed SO2 scrubber with NaOH recirculation, sized for 25,000 Nm³/hr flue gas, installed on a compact skid alongside existing ductwork with minimal civil intervention.
- Outcome: Stack SO2 reduced to 85-110 mg/Nm³ within 30 days of commissioning. Consent to operate renewed without further conditions.
Sulphuric Acid Plant
Tail Gas Treatment
Challenge
An integrated fertiliser complex emitted SO2 from its sulphuric acid plant tail gas at 3,000-4,500 ppm, creating regulatory pressure and a community relations problem.
Solution
A two-stage Envigaurd SOx scrubber system with independent recirculation loops and automated pH control was installed downstream of the converter to capture residual SO2 before stack discharge.
- Outcome: Outlet SO2 reduced to below 50 mg/Nm³ - meeting CPCB norms and the company's internal sustainability targets.
Rubber Vulcanisation Plant
Worker Safety
Challenge
A tyre component manufacturer reported elevated ambient SO2 inside the production hall from vulcanisation ovens, triggering worker health complaints and an EHS audit finding.
Solution
Envigaurd supplied a compact PP-shell SO2 scrubber with Na2CO3 recirculation to treat combined exhaust from four vulcanisation ovens, with an induced draft fan for negative pressure operation.
- Outcome: Ambient SO2 in the hall reduced by over 95%. EHS audit finding closed with corrective action accepted and worker health incident rate fell significantly.
Copper Ore Smelter
High-Volume SO2 Control
Challenge
A copper smelter required a gas treatment system capable of handling 80,000 Nm³/hr at inlet SO2 concentrations of 2,000-5,000 ppm from sulphide ore concentrate processing.
Solution
Envigaurd engineered a large-diameter FRP-reinforced packed bed scrubber with dual recirculation pumps, structured packing for low pressure drop, and a three-stage pH control system.
- Outcome: SO2 removal efficiency of 98.5% achieved consistently, with outlet concentrations below 100 mg/Nm³ across all operating load conditions.
These scenarios are representative application examples. Contact Envigaurd to discuss the specific SO2 challenge at your plant.
Trusted by Leading Industrial Plants Across India
How Envigaurd Delivers Your SO2 Scrubber
From first enquiry to lifetime support every stage is handled in-house by Enviguard’s own engineers. No subcontracting, no handoffs.
01
Design & Engineering
Every Envigaurd SO2 Scrubber begins with a detailed application review. Our in-house engineering team – with 10+ years of wet scrubber design experience – analyses your gas flow rate, SO2 concentration, temperature, and regulatory target to produce a site-specific design. No standard templates and no outsourced calculations. You receive a complete design basis document, process flow diagram, and mass balance before fabrication begins.
- Application-specific inlet and outlet parameter analysis
- Tower diameter, packing height, and L:G ratio calculation
- Material selection based on gas temperature, humidity, and chemical compatibility
- Full P&ID and instrumentation specification issued before order confirmation
02
Manufacture & Quality Control
Fabrication takes place entirely at Envigaurd’s manufacturing facility. Our in-house team fabricates the PP shell, FRP reinforcement, sump, and internal components under a defined quality plan. No subcontracting of structural or wetted components. Each scrubber undergoes dimensional inspection, hydrostatic testing, and a pre-dispatch checklist before leaving the factory.
- In-house PP sheet and FRP fabrication - no outsourced structural work
- Dimensional QC at each fabrication stage with photographic records
- Hydrostatic test of sump and shell before packing installation
- Pre-dispatch checklist signed off by QA and project engineer
03
Installation & Commissioning
Envigaurd’s commissioning engineers supervise installation at your site, align the scrubber to your existing ductwork, and commission the recirculation, pH dosing, and instrumentation systems. We do not hand over a scrubber until it has demonstrated compliant outlet SO2 concentrations under actual operating conditions, with all parameters recorded in a commissioning report.
- On-site supervision by Envigaurd engineers - no third-party agencies
- Recirculation pump, pH dosing, and control panel commissioning included
- Performance test with stack measurement against CPCB SO2 norms
- As-built drawings and commissioning report issued at handover
04
Maintenance & Support
After handover, Envigaurd remains your technical partner. Our AMC programmes cover scheduled packing inspections, nozzle checks, pump service, and pH probe calibration. Our technical helpdesk responds within 24 hours for operational queries, and our field team can mobilise within 48 hours for critical issues. With 10+ years of scrubber operation data across multiple industries, we bring proven maintenance protocols to your plant.
- Annual maintenance contract (AMC) with defined visit frequency and scope
- Preventive maintenance schedule for pump, packing, nozzles, and instrumentation
- Spare parts supply from Envigaurd's stocked inventory
- 24-hour technical helpdesk and 48-hour field response SLA
Why Choose Envigaurd for Your SO2 Scrubber?
10+ Years of SO2 Scrubber Expertise
Envigaurd has designed and commissioned SO2 scrubbers across sulphuric acid plants, boilers, smelters, and chemical industries - bringing application-specific knowledge accumulated over more than a decade to every new project.
Full In-House Lifecycle
No Subcontracting: Design, fabrication, installation, and AMC are performed by Envigaurd's own team. This eliminates coordination risk, preserves quality control, and gives you a single accountable partner for the entire scrubber lifecycle.
Application-Specific Engineering
We do not apply standard sizes to every enquiry. Each SO2 scrubber is sized to your actual gas flow, SO2 concentration, temperature, and compliance target - no over-engineering, no under-sizing.
Material Mastery for Corrosive Applications
Our engineers select PP, FRP, SS 316, and alternative materials based on decades of experience with acidic, high-humidity flue gas streams - not on generic compatibility charts alone.
Pan-India Project Execution
With active installations in 18+ states, Envigaurd's logistics and commissioning teams are experienced in pan-India project delivery, including remote industrial locations.
Compliance Guarantee
Every scrubber is sized to achieve CPCB SO2 norms of ≤200 mg/Nm³ or better. Our commissioning report includes verified stack measurement data against the applicable regulatory standard.
Comprehensive AMC & After-Sales Support:
Long-term AMC programmes, fast spare parts supply, and a responsive technical helpdesk ensure your SO2 scrubber delivers compliant performance year after year - not just at commissioning.
Low Lifecycle Cost
PP/FRP construction, efficient packing design, and optimised reagent recirculation minimise energy consumption, chemical usage, and replacement part frequency over the scrubber's service life.
Envigaurd delivers SO2 scrubbers that perform to specification at commissioning and continue performing for years after. From first enquiry to annual maintenance, your plant’s compliance is our commitment.
SO2 Scrubber vs. Alternative SO2 Control Technologies
| Criterion | Envigaurd SO2 Scrubber (Wet) | Dry Lime Scrubber | Activated Carbon Adsorber | Bag Filter |
|---|---|---|---|---|
| SO2 Removal Efficiency | Up to 99%+ single-stage | 70–90% | 60–80% (SO2 specific) | Not applicable |
| SO2 Concentration Range | 100–5,000 ppm | 500–5,000 ppm | 100–500 ppm (low load) | N/A for gaseous SO2 |
| Material Compatibility | PP/FRP - excellent acid resistance | Mild steel (limited life) | Carbon - moisture-sensitive | Fabric - corrodes with acid gas |
| Operating Cost | Low - reagent recirculation | Moderate - dry reagent waste | High - carbon replacement | Low - no SO2 removal |
| Maintenance Frequency | Low - semi-annual checks | Moderate - reagent & waste | High - carbon regeneration | Low - pulse-jet cleaning |
| CPCB SO2 Compliance | Yes - designed to ≤200 mg/Nm³ | Marginal - case-by-case | Limited - not for high loads | No - no SO2 removal |
| Particulate Handling | Limited - pre-filter recommended | Yes - simultaneous SO2+PM | No - pre-filter required | Yes - primary function |
| CAPEX Range | Moderate - high-value long life | Low–Moderate | Moderate–High | Low (SO2 not addressed) |
* Disclaimer: Data represents general industry performance ranges. Actual results depend on site-specific gas conditions, reagent selection, and system design. Contact Envigaurd for a detailed technology comparison for your application.
Certifications & Regulatory Compliance
CPCB SO2 Emission Norms
General Industries: ≤200 mg/Nm³ (stack concentration at standard conditions)
Environment Protection Act
1986 - Schedule I emission standards for sulphur dioxide
IS 2379
Colour coding and pipework identification for industrial installations
IS 1538
Flanges and flanged fittings (gas-side connections)
Factories Act
1948 - Workplace air quality provisions relevant to SO2 exposure limits
MoEFCC Guidelines
Stack emission monitoring frequency and reporting requirements
Envigaurd designs every SO2 Scrubber to meet or exceed applicable CPCB emission norms and the requirements of the Environment Protection Act. Our commissioning process includes verified stack emission measurement, and we provide documentation suitable for submission to the State Pollution Control Board as part of your consent-to-operate renewal.
HCl Scrubber Technical & Commercial FAQs
15 questions answered by Enviguard’s application engineers. For questions not covered here, contact our team directly.
A wet SO2 scrubber uses counter-flow liquid-gas contact across a packed bed to create an extremely large surface area for SO2 absorption. The continuous flow of fresh alkaline liquor maintains the concentration gradient needed for mass transfer, enabling efficiencies of 99%+ that dry sorbent systems typically cannot match at high inlet concentrations. Contact Envigaurd for a detailed technical assessment.
NaOH (caustic soda) reacts faster with SO2 and achieves lower outlet concentrations, making it suitable for high-inlet applications (500–5,000 ppm). Na2CO3 (soda ash) is less aggressive, lower cost, and preferred for moderate concentrations (100–1,000 ppm) where pH buffering is an advantage. Envigaurd selects the reagent based on your inlet SO2 level, outlet target, and operating cost priorities. Contact Envigaurd for a detailed technical assessment.
The packed bed SO2 Scrubber provides limited particulate capture as a secondary function but is not designed as a primary particulate control device. Where both particulate and SO2 removal are required, Envigaurd recommends a venturi pre-scrubber or cyclonic separator upstream of the packed bed. This protects packing from fouling and optimises each unit for its primary function. Contact Envigaurd for a detailed technical assessment.
The spent scrubbing liquor containing sodium sulphate and sodium sulphite must be treated before disposal. In plants with an effluent treatment plant (ETP), blowdown can typically be routed to the ETP for pH neutralisation and settling. Envigaurd provides a blowdown analysis and disposal recommendation as part of the project engineering package. Contact Envigaurd for a detailed technical assessment.
The spent scrubbing liquor containing sodium sulphate and sodium sulphite must be treated before disposal. In plants with an effluent treatment plant (ETP), blowdown can typically be routed to the ETP for pH neutralisation and settling. Envigaurd provides a blowdown analysis and disposal recommendation as part of the project engineering package. Contact Envigaurd for a detailed technical assessment.
A submersible or inline pH sensor monitors sump liquor alkalinity continuously. When pH drops below the set point (typically 7.5–8.5 for NaOH systems), the automated dosing system opens a control valve to inject fresh NaOH or Na2CO3 concentrate from a day tank. This closed-loop control maintains consistent absorption efficiency and prevents reagent wastage from overdosing. Contact Envigaurd for a detailed technical assessment.
The primary inputs for scrubber sizing are: gas flow rate (Nm³/hr), inlet SO2 concentration (ppm or mg/Nm³), gas temperature at the scrubber inlet, presence and concentration of other acid gases or particulates, target outlet SO2 concentration, and available headroom for tower installation. Envigaurd's sizing questionnaire captures all required data. Contact Envigaurd for a detailed technical assessment.
A single-stage Envigaurd SO2 Scrubber handles inlet concentrations up to 5,000 ppm efficiently. Above this level, a two-stage configuration - each stage with independent recirculation - is recommended to maintain high removal efficiency and manage reagent consumption. For SO2 concentrations above this range (primary smelter gas), upstream treatment options should be considered. Contact Envigaurd for a detailed technical assessment.
PP Pall ring packing in a properly operated SO2 scrubber typically lasts 5–10 years before structural degradation or fouling requires replacement. Service life depends on particulate presence, operating temperature (PP is rated to 80°C continuous), and the effectiveness of liquor blowdown management. Envigaurd's AMC programme includes annual packing inspection and replacement advisory. Contact Envigaurd for a detailed technical assessment.
Standard scrubber units (up to 25,000 Nm³/hr) have a manufacturing lead time of 4-6 weeks from drawing approval. Larger custom systems (up to 100,000 Nm³/hr) require 8–12 weeks. Commissioning typically adds 1-2 weeks on-site. Envigaurd maintains a stock of PP sheet and packing material to minimise lead time on urgent compliance-driven orders. Contact Envigaurd for a detailed technical assessment.
Yes. Envigaurd's AMC programmes are available from commissioning handover. Scope includes scheduled visits (typically 2–4 per year), packing inspection, nozzle and pump service, pH probe calibration, and a written report after each visit. Emergency call-out is included with a defined response SLA. Contact Envigaurd for a detailed technical assessment.
Yes. Retrofitting is a significant part of Envigaurd's project portfolio. Our team surveys the existing duct layout, fan capacity, and space constraints, then designs the scrubber to integrate with minimal modification to existing civil and structural elements. Skid-mounted configurations are often preferred for retrofits. Contact Envigaurd for a detailed technical assessment.
Routine maintenance includes: weekly checks of pump operation, pH reading, and liquor level; monthly inspection of spray nozzles for blockage; quarterly mist eliminator condition check; semi-annual packing inspection; and annual pump seal and bearing replacement. Envigaurd provides a detailed O&M manual and site-specific maintenance schedule at commissioning handover. Contact Envigaurd for a detailed technical assessment.
The primary causes of performance loss are: (1) pH drop due to inadequate reagent dosing or a failed pH probe; (2) nozzle blockage reducing liquor distribution over the packing; (3) packing fouling from particulates in the inlet gas; and (4) pump failure causing loss of recirculation flow. Envigaurd's AMC visits are structured to identify and correct these issues before they cause a compliance exceedance. Contact Envigaurd for a detailed technical assessment.
Under the Environment Protection Act and its associated schedules, CPCB prescribes an SO2 stack emission limit of ≤200 mg/Nm³ for general industries, including boilers burning coal or other sulphur-containing fuels. Some sector-specific notifications impose stricter limits. Envigaurd designs scrubbers to meet the applicable limit for your specific installation category. Contact Envigaurd for a detailed technical assessment.
Envigaurd's SO2 Scrubber is designed and tested to meet CPCB SO2 norms. The commissioning report - including verified stack emission measurement - is typically accepted by SPCBs as evidence of compliance for consent-to-operate renewal. Specific SPCB requirements vary by state; Envigaurd advises on any additional documentation your consent conditions require. Contact Envigaurd for a detailed technical assessment.
Downloads & Resources
Full Gate - Form Required
SO2 Scrubber Technical Datasheet
Complete technical specifications, material data, dimensional drawings, and performance curves for Envigaurd’s SO2 Scrubber range. Suitable for preliminary engineering and RFQ preparation.
Soft Gate - Email Only
SO2 Scrubber Sizing Questionnaire
A structured data sheet capturing gas flow, SO2 concentration, temperature, and site parameters Envigaurd needs to generate an accurate technical proposal. Submit the completed form to begin your enquiry.
Open - No Gate
Envigaurd Company Brochure
An overview of Envigaurd’s full portfolio of industrial air pollution control equipment, including wet scrubbers, dry scrubbers, mist collectors, and fume extraction systems.
Open - No Gate
CPCB SO2 Compliance Guide for Indian Industries
A plain-language guide to CPCB SO2 emission norms under the Environment Protection Act, stack monitoring requirements, and the role of wet scrubbers in achieving and maintaining compliance.
Get a Site-Specific SO2 Scrubber Proposal
Your process exhaust has unique parameters – gas flow, SO2 concentration, temperature, and space constraints. Envigaurd’s engineering team provides a detailed, accurate proposal based on your actual data, not a catalogue shortlist. Expect a technically grounded response within 48 hours of receiving your sizing questionnaire.
500+ systems installed across India. 10+ years of compliance-proven engineering. No obligation to proceed.
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Annual Maintenance Contract (AMC)
Structured preventive and corrective maintenance programmes for all Envigaurd scrubber installations - ensuring long-term performance and regulatory compliance.
All Industries
Scrubber Retrofitting Services
Engineering assessment and upgrade of underperforming third-party wet scrubbers - new packing, improved nozzle layouts, or full tower replacement.
All Industries
Ready to Solve Your SO2 Compliance Challenge? Let's Talk.
Whether your plant is facing a CPCB notice, planning a new installation, or upgrading an underperforming scrubber, Envigaurd’s team will assess your situation and propose the right solution. We offer no-obligation technical consultations and site visits across India.
500+ systems installed across India. 10+ years of compliance-proven engineering. No obligation to proceed.
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Maintenance Guide
SO2 Scrubber Maintenance: 10 Checks Every Operations Team Should Perform Quarterly
A practical maintenance checklist covering pH probe calibration, nozzle inspection, packing condition, pump seals, and mist eliminator cleaning for packed bed SO2 scrubber systems.
5 min read
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