Scientific blog · Soot scrubbers
Soot scrubber maintenance: tank, nozzles and pump
Artur Cokaj · · Updated
Planning checks for a wet scrubber serving a wood-fired oven or grill: the scrubbing circuit, deposits, nozzles and maintenance records.
Maintaining a water-based soot scrubber helps preserve the conditions required for flue gas scrubbing. Checks cover the entire process: available water, nozzle supply, deposit collection, liquid separation and flue gas passage. Frequencies and methods must follow the model's manual and the installation's conditions.
For a pizzeria with a wood-fired oven or a kitchen with a charcoal grill, preparing the schedule before commissioning helps fit maintenance around the business. Where the configuration has no mechanical filter requiring replacement, the water circuit still needs cleaning and inspection.
Start with the installed machine's manual
Identify the model, serial number, version and accessories. An automatic drain or make-up system changes the operations required but must still be checked in accordance with its instructions. For ETC Group S.r.l. systems, use the documentation for the specific supply and the reference for the NEWSCRUB AH family for wood and biomass. Available documents can be consulted in the ETC technical documentation section.
Work must be carried out by competent personnel, following the manual's procedures for shutdown, isolation of supplies, cooling and access to components. Do not open guards or work on electrical parts on the basis of a general guide.
What to check in the scrubbing circuit
| Part of the installation | Check to arrange |
|---|---|
| Tank and deposit collection | Liquid condition and accumulations, following the specified cleaning methods. |
| Nozzles and water distribution | Blockages or uneven distribution; cleaning using methods and tools permitted by the manual. |
| Pump and circuit | Steady operation, leaks or abnormalities; comparison with reference conditions. |
| Make-up and drain | Operation of the fitted devices and accessibility of connections. |
| Flue gas route and liquid separation | Deposits and abnormal passage or carry-over, using the checks specified for the machine. |
The EPA lists inadequate liquid flow, poor gas–water contact, blocked nozzles and carry-over among scrubber operating problems. These are general principles that help explain why maintenance affects operation; they do not establish service intervals for ETC products. EPA, monitoring particulate scrubbers.
Record abnormalities before changing settings
A change in noise, a leak, an irregular level or an unusual discharge should be recorded and assessed. Increasing fan speed or changing water settings without checking can alter treatment conditions. Where the machine has instruments, compare readings with the references in the design and manual.
Records may include the date, operating hours, process carried out, abnormality, work performed and person responsible. A photograph of the component, taken under safe conditions, can assist written support. The fault description must identify the machine and what has changed from normal operation.
Scrubbing water and residues need defined management procedures
Recirculation reuses water already in the circuit; make-up and blowdown serve different purposes. Arbitrarily reducing water changes to limit consumption can alter contaminant concentrations in the liquid. The balance and a worked example are explained in Water in scrubbers: recirculation, make-up and blowdown.
A drain fitted to the machine does not demonstrate that any liquid or residue may be discharged into the available network. Before operation, collection and management procedures applicable to the business and residue composition must be defined with the designer and the relevant competent parties.
Check the return to service
- Complete the work and reinstatement checks specified in the manual.
- Check reassembly, closures, connections and circuit conditions in accordance with the machine's procedures.
- Record the restart outcome and any remaining abnormalities.
- If the treatment result is in doubt, request a technical assessment: visual inspection alone does not measure emission removal efficiency.
The scrubbing principle is described in the guide to soot scrubber operation. To prepare an ETC support request, submit the model details and installation description through the company contacts.