≤ 10 mg/Nm³ @ 6 % O₂ dry
ESP outlet, adequate SCA
Technology · Gas cleaning range
Particulate emission control technology: matching collector to dust, gas and limit
Six collection technologies, one selection problem: match particle size, ash resistivity, gas temperature and the permit limit to the right collector. An ESP reaches 10 mg/Nm³ with adequate SCA; the Electrocyclone takes 85–95 % ahead of it at up to 400 °C; a bag filter goes below 10 mg/Nm³ at 100–150 mmWC fan penalty. The data decides.
85–95 %
Electrocyclone stage collection
≤ 400 °C
Electrocyclone service temperature
< 10 mg/Nm³ @ 6 % O₂ dry
Bag filter outlet, new media
01 — Selection logic
How particulate emission control technology is selected
Four measurable properties decide the collector. Marketing does not.
Every dust collector is a trade between outlet concentration, temperature tolerance, fan energy and sensitivity to the dust itself. Nothing wins on all four axes, which is why Arrow Energy Co., Ltd. builds six technologies rather than one. Selection starts from the process data — the same data a plant energy and emission audit produces — and from the permit limit written as it will be enforced: mg/Nm³ at a stated reference O₂, dry.
Which dust collector do I need?
It depends on four measurable things: particle-size distribution (a bagasse train-inlet d₅₀ of 21 µm behaves nothing like cement raw-meal dust), ash resistivity (an ESP works between about 10⁴ and 10¹¹ Ω·cm), gas temperature at the tie-in, and the permit limit in mg/Nm³ at stated O₂. Send a fuel analysis, a fly-ash sample and the gas flow in Nm³/h, and the selection follows from arithmetic, not preference.
On heavy raw-gas loads the answer is usually two stages, not one bigger collector. In our worked design basis — 60 t/h bagasse boiler, 6,000 mg/Nm³ at 6 % O₂ dry at train inlet — an Electrocyclone first stage removes 88 % of the load, and a four-field electrostatic precipitator collects 96.67 % of the remainder for 24 mg/Nm³ at the stack: 99.60 % overall, with 57 mg/Nm³ still available with one ESP field out of service. Comparable trains are documented, on a stated basis, under ESP project references.
02 — Envelopes
The selection table
Indicative envelopes from Arrow technical note AE-TN-EC-ESP-01 — design figures, not guarantees.
| Technology | Typical outlet envelope | Gas temperature ceiling | ΔP / energy | Most sensitive to |
|---|---|---|---|---|
| Electrostatic precipitator (ESP) | 30–50 mg/Nm³ retrofit basis; ≤ 10 mg/Nm³ with adequate SCA | ≤ 200 °C (design ~150–180 °C bagasse) | Low gas-side ΔP; absorbed power order 250 kW mid-size | Ash resistivity, gas distribution |
| Electrocyclone (proprietary) | 50–80 mg/Nm³ standalone; 85–95 % as a stage | ≤ 400 °C | 120–140 kW; near-zero moving-part maintenance | Inlet particle-size distribution |
| Bag filter | < 10 mg/Nm³ on new media | Media-limited | 100–150 mmWC new, 150–200 mmWC late in bag life | Temperature excursions, embers, moisture |
| Multicyclone | 65–85 % collection — pre-collection duty only | High; mechanical only | 80–120 mmWC, no electrical power | Blind below ~20 µm; tube erosion |
| Wet scrubber | Duty-dependent; captures gases and particulate together | Quenches gas to saturation | Highest ΔP of the range (venturi 500–800 mmWC) | Water balance, corrosion, visible plume |
| Flue-gas treatment | Acid-gas control (SO₂, HCl); dust falls to the paired collector | Process-dependent | Reagent consumption + collector ΔP | Reagent stoichiometry, temperature window |
Read the table as a system, not a menu: the choice sets the induced-draught fan size, the ash-handling layout, the temperature window available to heat recovery, and what happens when one section trips. Guaranteed figures are stated per project after the technical assessment, on a stated basis — mg/Nm³, reference O₂, dry or wet, load range. How each industry's fuel pushes the selection is mapped on the industries pages.
03 — The range
Six technologies, in depth
Each pillar page carries the sizing method, the envelope and the worked numbers.
Field-charged plate collection
Electrostatic precipitator
Deutsch-Anderson and Matts-Öhnfeldt sizing, SCA 75.7 s/m worked example, resistivity limits, n−1 arithmetic — plus eight component pages covering electrodes, rapping, TR sets, controllers, gas distribution, insulators and drives.
Electrostatic precipitator design and sizingProprietary hybrid
Electrocyclone
Cyclonic separation with electrostatic augmentation in one casing: 85–95 % stage collection at up to 400 °C, 60–65 % of an ESP's footprint, near-zero moving-part maintenance.
Electrocyclone pre-collectorFabric filtration
Bag filter
Below 10 mg/Nm³ regardless of ash resistivity, paid for at 100–150 mmWC of fan head: media selection, air-to-cloth and can velocity, pulse-cleaning design.
Bag filter design and media selectionMechanical separation
Multicyclone
65–85 % collection with no electrical power and no media — the honest envelope of centrifugal separation, and where it stops making sense.
Multicyclone collectorsWet collection
Wet scrubber
Particulate and soluble gases in one vessel, with the water-treatment, corrosion and plume consequences stated plainly.
Wet scrubber systemsAcid-gas control
Flue-gas treatment
SO₂ and HCl abatement matched to the particulate train — sorbent injection and the temperature windows that make it work.
Flue-gas treatment systemsFAQ
Engineering questions, answered
Which dust collector is best for a biomass boiler?
On bagasse and similar biomass, a two-stage train usually wins: an Electrocyclone removes 85–95 % of the load at up to 400 °C, and a four-field ESP finishes the rest — 6,000 to 24 mg/Nm³ at 6 % O₂ dry in our design basis. A bag filter suits limits below 10 mg/Nm³ if the fan can carry 100–150 mmWC.
What data do I need to send for a dust collector selection?
Five items: fuel analysis with moisture (bagasse runs ~50 % as fired), gas flow in Nm³/h, gas temperature at the tie-in point, the permit limit in mg/Nm³ at stated reference O₂, and a fly-ash sample for particle-size distribution and resistivity. With these, selection and budget sizing follow without site assumptions.
Can a single collector meet a 30 mg/Nm³ limit on its own?
Often, yes. A single ESP on a typical retrofit basis reaches 30–50 mg/Nm³ at 6 % O₂ dry, and 10 mg/Nm³ or below with adequate specific collecting area; a bag filter goes below 10 mg/Nm³ on new media. On heavy raw-gas loads a pre-collector stage cuts the size and cost of whichever finisher you choose.
Send us your plant data
Fuel, boiler capacity, gas flow, current emission and the limit you must meet. An Arrow engineer replies with a technical assessment basis — not a brochure.