Flue Gas Scrubber System manufacturing for Chemical & Process Plants

The inlet quench section uses direct contact with a liquid spray typically water or dilute scrubbing liquor to cool hot flue gas from its process exit temperature (which may be 150-400°C) down to the operating range of the PP/FRP packed bed (typically 40-65°C). This cooling step is essential when PP or FRP construction is used, as these materials have defined temperature limits. It also saturates the gas with moisture, improving SO₂ absorption in the downstream scrubber. Where inlet gas temperature is already below 60°C, the quench section may be simplified or omitted; for high-temperature streams, high-temperature alloy internals may be specified at the quench inlet.

Yes - both SO₂ and HCl are acid gases that are effectively absorbed by alkaline NaOH or lime solution in a packed bed scrubber. A single two-stage unit with optimised pH control in each stage can achieve high removal of both contaminants simultaneously. The challenge is that optimal pH windows for SO₂ and HCl absorption differ slightly; Enviguard addresses this through staged reagent dosing and inter-stage pH control. For very high concentrations of both contaminants, two dedicated packed beds in series may be specified. The process chemistry, inlet concentrations, and required outlet limits determine the final configuration.

Enviguard's standard product range covers gas flow rates from approximately 500 Nm³/h (small process vent) up to 50,000 Nm³/h (large boiler or multi-source combined). Units beyond this range are custom-engineered. For very small flows (<500 Nm³/h), a compact packaged scrubber unit may be appropriate. For flows above 50,000 Nm³/h - typical of large captive power boilers  a custom multi-module or large-diameter tower design is assessed on a project-specific basis. All sizing starts from your actual inlet gas parameters, not a catalogue standard.

For a standard skid-mounted flue gas scrubber unit (up to ~10,000 Nm³/h), Enviguard's typical timeline from purchase order to ready-for-stack-test commissioning is 6–8 weeks. This includes design finalisation (1-2 weeks), in-house fabrication and shop testing (3-4 weeks), dispatch, site installation, and commissioning (1-2 weeks). Larger field-erected units or projects requiring civil construction may have extended timelines discussed and agreed at order stage. Enviguard provides a project schedule at enquiry stage for your planning purposes

Standard scope of supply includes: inlet quench section (MS/SS), main scrubber vessel (PP/FRP), packing media (PP or ceramic), mist eliminator, recirculation tank, recirculation pump(s), spray nozzles and liquid distribution system, structural skid, reagent dosing system, instrumentation (pH, flow, level), CEMS inlet and outlet tapping nozzles, and electrical panel. Optional scope includes ID/FD fan, stack, civil foundation design, CEMS analysers, and annual maintenance contract. Scope is tailored to each project during technical discussion.

The most critical daily monitoring parameters for a flue gas scrubber system are: (1) Scrubbing liquid pH - maintaining the design pH (typically 8-11 for NaOH systems) directly correlates with SO₂/HCl removal efficiency; (2) Recirculation flow rate - reduced flow indicates pump issues or nozzle fouling; (3) Scrubber pressure drop a significant increase suggests packing fouling or mist eliminator blockage; (4) Reagent consumption rate deviations from baseline indicate changes in inlet pollutant loading or pH drift; (5) Blowdown conductivity rising conductivity indicates salts build-up requiring increased blowdown. Enviguard provides a commissioning-stage O&M manual with all target ranges.

At project closure, Enviguard provides: (1) A third-party accredited stack test report confirming outlet concentrations for each target pollutant; (2) A system performance certificate from Enviguard confirming the system meets the guaranteed outlet concentrations; (3) CEMS commissioning record confirming inlet and outlet tapping nozzle installation per IS 11255; (4) Equipment data sheets for the scrubber, pump, and fan for the plant's equipment register; (5) An O&M manual for operator training and inspection records. These documents collectively support your CTO renewal, EIA condition compliance demonstration, and SPCB inspection submissions.