Plastic Waste Gas Treatment: Capture, Purification and Compliance for Plastics Processing

Key Takeaways

“Plastic waste gas” is read two different ways online. This page is about the exhaust air from plastics processing — injection moulding, extrusion, blow moulding, thermoforming, granulation — not about plastic-to-fuel pyrolysis.
The pollutant profile is set by the resin and the processing temperature together. PVC gives hydrogen chloride, ABS and PS give styrene, nylon gives caprolactam, acetal gives formaldehyde, polyolefins give alkanes, alkenes and a heavy condensable aerosol.
Most plastic fume systems fail for one of two reasons: the hood never captured the fume in the first place, or condensable wax and oligomer blinded the activated carbon within a few months.
Activated carbon must be sized on working capacity, EBCT and bed velocity — three numbers. A quoted bed weight without a flow rate is not a design.
Grinding dust and process fume are different problems under different codes. Combustible plastic dust needs a dedicated dry collector with explosion protection; it must never be routed through the gas-phase train.
Fix the target standard before the design. GB 16297, GB 31572 and GB 37822 for Chinese projects; the receiving country’s standard or the client’s permit condition for export projects.

What Plastic Waste Gas Treatment Actually Covers (And What It Does Not)

Why “plastic waste gas” is read two different ways

Search for plastic waste gas treatment and you will land, more often than not, on pyrolysis. That is a different industry with different chemistry, different equipment and different regulations. Pyrolysis takes waste plastic and thermally decomposes it into syngas, pyrolysis oil and carbon black — the “waste gas” there is a product you want to keep and burn. The subject of this page is the opposite: the dilute exhaust air that a plastics processing plant produces and must clean before it leaves the stack.

The confusion matters commercially, because the two subjects attract the same search terms and the same suppliers’ marketing. If you run moulding presses, extrusion lines or a granulation department, nothing on a pyrolysis page applies to you. Your exhaust is cool, dilute, and dominated by solvent vapour, acid gas and a condensable aerosol — and your obligation is a stack limit plus a workplace exposure limit, not a fuel specification.

The four exhaust streams this page is about

A plastics plant rarely has one exhaust problem. It usually has four, and they need different capture principles and different treatment trains.

Process exhaust at the machine. The heating barrel, the nozzle, the die exit and the mould parting line. This is the continuous stream that carries the solvent and monomer vapours.
Non-routine exhaust. Purging, colour changes, start-up and burning out blocked nozzles. Short in duration, far higher in concentration than normal production, and routinely left out of the sizing calculation.
Particulate and dust exhaust. Grinding, trimming, deflashing, regrind and material handling. A solid-phase problem with a deflagration hazard attached.
Downstream solvent exhaust. Printing, bonding, welding and coating operations on the finished part, which can carry a higher solvent load than the moulding line itself.

Where plastics-processing exhaust is generated in a plant

Walking a plant from the material store to the shipping bay, the emission points are consistent: pellet drying and dosing, the heating barrel and nozzle, the purge station, the die exit and cooling bath on an extrusion line, the mould parting line and ejector area, the trim and cooling station, the granulator and regrind system, and the welding or assembly bench. Each point contributes a different fraction of the total load. A capture survey that treats them as one lumped source will over-ventilate the clean points and under-capture the dirty ones.

Where the Pollution Comes From: Resin Chemistry vs Processing Temperature

Resin-by-resin emission profile

The fume from a plastics process is not a fixed substance. It is the breakdown and volatilisation product of a specific polymer, its additives, and the temperature history it has seen. The table below is the starting point for any design — the resin list tells you which treatment stages you need before you size anything.

Resin	Typical processing window	Dominant fume constituents
PVC / PVDC	170–200 °C	Hydrogen chloride, plasticiser vapours, phthalate esters
ABS / SAN	220–260 °C	Styrene, acrylonitrile, butadiene-derived species
PS / EPS	200–250 °C	Styrene, ethylbenzene, toluene
PP / PE	200–280 °C	Alkanes and alkenes, formaldehyde and acrolein on over-temperature, heavy wax and oligomer aerosol
PA (nylon)	260–300 °C	Caprolactam, ammonia, amines
POM (acetal)	190–210 °C	Formaldehyde — narrow window, blowout risk if the material overheats
PUR	Process dependent	Isocyanates (MDI / TDI), amines
PC / PBT / PPS	280–330 °C	Phenols, esters, aromatic hydrocarbons

Beyond the base polymer, the additives produce their own breakdown products. Flame retardants, pigments, stabilisers, fillers, plasticisers and blowing agents all have thermal behaviour of their own, and switching to a new formulation within the same polymer family can change the fume hazard profile completely. The safety data sheet for every formulation you run belongs in the design file, not just the one for the base resin.

Why temperature and residence time change the pollutant, not just the amount

Below the degradation threshold, the volatiles are mostly residual monomer, moisture, low-molecular-weight fractions and additive carry-over. Above it, chain scission begins and the profile shifts qualitatively: more formaldehyde from polyolefins and acetal, more hydrogen chloride from PVC, more aromatic cracking fragments from styrene-based resins. Residence time in the barrel compounds the effect, because a longer dwell at temperature is more thermal history.

The practical consequence is that two plants running the same resin at different setpoints do not emit the same compounds and cannot be given the same treatment train. It also means that a system designed for a supplier’s resin sample can under-perform when the plant changes grade or raises the barrel temperature to improve cycle time. Design for the worst credible case in the resin list you were given, and confirm the list.

The purge, regrind and start-up spikes nobody sizes for

Purge and burn-out produce concentrations an order of magnitude above steady-state production. If the system is sized only on normal running, these are the events that saturate the carbon, trip odour complaints at the fence line and, on a PVC line, dump a concentrated acid load into a scrubber that was tuned for a fraction of it. There are only two honest answers: include boost capacity for these events, or write a documented procedure that isolates them and extracts them separately. What does not work is designing for steady state and hoping.

The Pollutants You Are Actually Dealing With

NMHC and the aromatic fraction

Non-methane hydrocarbons are the regulatory handle in most Asian jurisdictions and the practical handle everywhere, because the aromatic fraction dominates both by mass and by odour. The set that recurs across plastics processing is benzene, toluene, ethylbenzene, styrene and the xylene isomers, with styrene as the tracer for ABS and PS lines and the C8 aromatics plus higher alkanes such as undecane typical of polyolefin processing. These are the compounds that set the carbon bed sizing and the ones an inspector will sample for.

Oxygenated compounds: acetone, MEK, ethyl acetate, butyl acetate

Oxygenated solvents appear wherever the plant prints, bonds, welds or coats the moulded part, and on pelletising lines that use solvent-borne additives. Ketones and esters behave differently from the aromatics in one way that changes the design: acetone and methyl ethyl ketone are water-miscible, so a meaningful part of that load can be removed in a wet stage rather than carried onto carbon. Recognising which fraction of your load is water-soluble is often the difference between a two-stage and a three-stage system.

Acid gases and the PVC problem

Hydrogen chloride from PVC and PVDC is the single most destructive component in plastics-processing exhaust. It is corrosive to carbon steel, it attacks aluminium and galvanised surfaces, it acidifies condensate so that the whole ductwork becomes a corrosion cell, and it poisons activated carbon. Any line running chlorinated resin needs a wet alkaline scrubbing stage ahead of the carbon, wetted parts in PP, PVC, FRP or 316L, and a realistic chloride load in the material specification. There is no shortcut here, and a carbon-steel system on a PVC line will fail within a season.

Smoke, particulate and condensable aerosol

Three different particulate problems arrive together. Grinding and trimming produce dust with a deflagration hazard. Over-temperature barrels produce sub-micron smoke. And hot vapour cooling in the duct produces a condensable aerosol that gives plastic fume its characteristic visible haze and its sticky feel on duct walls. The aerosol is the one that damages treatment equipment rather than people, and it is the one most often omitted from a system design.

Emission Standards and Exposure Limits That Apply

Stack standards: GB 16297, GB 31572, GB 37822

For projects in China, three standards do most of the work. GB 16297-1996, the integrated emission standard of air pollutants, is the general standard that sets limits on particulate matter, non-methane hydrocarbons and specific species against stack height — this is the “national second-level emission standard” that older Chinese process descriptions refer to. GB 31572-2015 is the emission standard for the synthetic resin industry and applies directly to resin producers across PVC, polyolefin, ABS, polystyrene, polyester and polyurethane. GB 37822-2019 is the comprehensive standard for volatile organic compounds, and it governs the fugitive and unorganised side: leakage from equipment and open handling, and the obligation to collect and treat rather than disperse.

For export projects the receiving country’s standard applies, and it is frequently modelled on US EPA or EU BREF practice with local tightening on top. The design consequence is the same either way: the target has to be stated before the sizing calculation, because the required removal efficiency determines the stage count and the stage count determines the capital cost.

Worker-exposure limits: OSHA PEL, ACGIH TLV, HSE WEL

Worker exposure limits and stack limits are different obligations, and in a well-designed plant they are satisfied by different parts of the system. Capture at the machine protects people; treatment at the stack protects the fence line. A system that meets the stack limit with a badly hooded machine can still fail an occupational inspection, and vice versa.

Compound	Typical occupational limit	Source resin
Styrene	OSHA PEL 100 ppm TWA; ACGIH TLV 20 ppm	ABS, PS, unsaturated polyester
Formaldehyde	OSHA PEL 0.75 ppm TWA, 2 ppm STEL	POM, PP, acetal copolymers
Hydrogen chloride	5 ppm ceiling	PVC, PVDC
Acrolein	0.1 ppm TWA / 0.3 ppm STEL	Polyolefins at over-temperature
Acetone	500–1000 ppm TWA depending on regime	Solvent-borne additives, downstream bonding
Phenol	5 ppm TWA	Phenolic resins, PC
Isocyanates (MDI)	0.02 ppm ceiling	Polyurethane

Note the gap between the two columns. The ACGIH threshold limit value for styrene is a fifth of the OSHA permissible exposure limit, and although a TLV is a recommendation rather than a regulation, many authorities will cite a recognised guideline as evidence of a hazard that should have been controlled. Designing to the tighter of the two is the defensible choice.

Combustible plastic dust: NFPA 660 and Kst

Grinding, trimming, sanding and regrind produce plastic dust, and most common plastics — polyethylene, polypropylene, ABS, nylon — have Kst values that place them in explosion class St1 or St2. That makes the dust a deflagration hazard, not a housekeeping nuisance. NFPA 660, effective from January 2026, consolidates the previous combustible dust standards and requires a dust hazard analysis for any operation generating combustible dust, together with explosion venting, suppression or isolation on the collector.

The design consequence is a hard separation of duties. The dust collector and the gas-phase treatment train are separate systems under separate codes, and grinding dust must never be routed through a wet scrubber or an activated carbon bed. Doing so creates a hazard inside a vessel that was never designed to contain it.

When a plastics plant crosses the permitting threshold

The threshold is a mass emission, not a machine count. As one worked reference point, a US state exempts plastic extrusion and moulding facilities from air permitting unless facility-wide criteria pollutant emissions reach five tons per year, and separately regulates hazardous air contaminants against compound-specific action levels. European and Asian regimes use different numbers but the same structure: a small shop may be exempt while a plant with many presses and a coating line is not.

What determines your position is resin throughput, the fraction volatilised, and annual operating hours — which is why the input data for the calculation is your production record, not your equipment list.

Capture First: Why Half of All Plastic Fume Systems Fail at the Hood

Capture volume per processing point

A treatment train can only clean what the hood delivers to it. Under-capture means the pollutant escapes into the hall and the exposure limit is breached regardless of how good the stack is. Over-capture means you pay to move and treat air that never contained anything, for the life of the plant.

The working method is to take the closest practicable enclosure at each point — an enclosing hood on the purge and nozzle area, a close-fitting receiving hood at the die exit, a canopy only where nothing better is physically possible. Capture velocity at the source has to exceed the local draught, and the hood must be sized from the plume it is trying to catch, not chosen from a fan catalogue. Capture points should be measured after installation, not assumed from the drawing.

Duct transport velocity for condensable-laden air

Plastic fume condenses as it cools, and this changes the duct design rule. Too low a velocity and condensate wets the wall, dust sticks to the wet film and the duct gradually closes. Too high and pressure loss and fan power climb, while the sticky deposit is more likely to be torn off and carried onto the filter. The transport velocity has to be chosen for the heaviest condensable you expect, not for clean air.

The places fouling starts are predictable: bends, horizontal runs and dead legs. Slope horizontal runs toward a drain, fit clean-outs and inspection ports at every change of direction, and where the layout allows, avoid long horizontal runs altogether. A duct designed for access is a duct that stays open.

Hood selection: enclosing, receiving, or elephant trunk

Enclosing hood. Highest capture efficiency, and the right choice for purge stations and nozzle areas where the operator works close to the source.
Receiving hood. For the die exit and cooling section on extrusion lines, where the plume is directional and the process cannot be enclosed.
Flexible arm or elephant trunk. For intermittent sources — granulator discharge, regrind, welding, trim benches — where a fixed hood would obstruct the work.

Whichever type is used, the capture point must not interfere with mould changes, robot access or cycle time. If it does, operators will defeat it, and the best-designed treatment train downstream becomes decorative.

The Treatment Train, Stage by Stage

Stage 1 — demisting and aerosol removal

Before anything else, remove the liquid and semi-liquid fraction. A demister — knitted wire mesh or a vane pack — knocks out droplets and the heavier condensable aerosol by impaction. This stage protects everything downstream, and omitting it is the most common single cause of premature carbon failure.

On a plastics line, our wet scrubber and cyclone tower normally serves as the first wet stage: it performs the demisting duty and begins gas absorption in the same vessel.

Stage 2 — wet scrubbing for water-soluble and acid gases

A wet stage removes hydrogen chloride, ammonia and amines, the water-soluble oxygenates, and the remaining particulate in a single pass. For acid gases the scrubbing liquor is recirculated with automatic dosing to hold pH in the alkaline range — typically sodium hydroxide solution — with a controlled bleed to limit dissolved solids and a make-up line to replace what is consumed.

The internals exist to maximise gas-liquid contact. Gas enters through a gradually expanding inner cylinder and an equalising grid, passes a packing layer, and meets a counter-current spray. Our gas scrubber designs are built to hold gas-liquid mixing above 97%, which is the difference between a scrubber that meets its limit on commissioning day and one that still meets it in year three. Wetted materials follow the chloride load and temperature: PP, PVC, FRP or 316L.

Stage 3 — activated carbon adsorption for the VOC fraction

Carbon is the workhorse for the aromatic and oxygenated fraction that survives the wet stage — benzene, toluene, ethylbenzene, styrene, xylene, undecane, acetone, methyl ethyl ketone and the acetate esters. Granular activated carbon in the 500–1500 m²/g specific surface range is the standard medium.

Carbon is not a filter that fills up uniformly. The mass-transfer zone migrates through the bed, and breakthrough occurs at the outlet well before the bed is saturated, which is why outlet monitoring and bed sampling are not optional. Carbon must also never see a wet, oily or particulate-laden stream. Hence the order of the train: demist, scrub, then adsorb. Our activated carbon adsorption tower is built for that position in the line.

Stage 4 — when to add UV photo-oxidation or catalytic oxidation

UV photo-oxidation oxidises odour-bearing molecules in the gas phase and is a good fit for large volumes of dilute odour that would otherwise demand very frequent carbon change-out. It does not mineralise everything, however: partial oxidation can generate intermediate aldehydes, so a UV stage is normally followed by a short carbon polishing bed, and the lamps and quartz sleeves must be protected from the condensable aerosol that would otherwise coat them.

Catalytic or thermal oxidation suits high-concentration or solvent-rich streams where destruction is more economical than adsorption. Catalytic oxidation runs far below thermal oxidation temperature, but the catalyst is poisoned by halogens, silicon, phosphorus and heavy metals — which is why a PVC stream is generally excluded from a catalytic route and a polyurethane stream needs specialist evaluation rather than a standard unit.

Stage 5 — induced draft fan, ductwork and stack

The fan sits at the end of the train so that the whole system runs under negative pressure. Any leak then pulls air in rather than pushing contaminated air out into the working hall, which is the single most important safety decision in the layout.

The fan must be specified on total system pressure loss with the filters at end-of-life, not clean — otherwise the system loses flow exactly when the media is doing the most work. Stack height and sampling provisions follow the applicable standard: GB 16297 sets stack height against emission rate, and monitoring platforms and sampling ports are part of the design rather than an afterthought. Retrofitting a platform onto a finished stack is expensive.

Sizing the Activated Carbon Bed Correctly

The three numbers that size a carbon bed

Three quantities determine whether a carbon vessel works, and any two of them determine the third.

EBCT — empty bed contact time. Bed volume divided by volumetric flow. It is the residence time the gas spends in the bed.
Bed velocity — superficial velocity. Flow divided by cross-sectional area. It governs pressure drop and how hard the mass-transfer zone is pushed through the bed.
Working capacity. The mass of target compound the carbon will hold per unit mass before the outlet concentration reaches its limit — not the same as the equilibrium capacity printed on a datasheet.

A supplier who quotes a bed weight without a corresponding flow rate has not sized anything. Ask for all three, at the design flow, and ask what the numbers become during purge and start-up.

Working capacity vs equilibrium capacity

Equilibrium capacity is measured on a clean, single-component stream over a long period. Real plastics exhaust is a multi-component mixture at a few hundred milligrams per cubic metre, at elevated temperature, with humidity present. Working capacity — the usable fraction of the bed before breakthrough — is lower than equilibrium capacity, and on a sticky plastic-fume stream it is lower again, because condensate occupies pore volume that should have been available for adsorption.

The rule that follows is simple: size on working capacity, then add margin for the fouling you cannot yet quantify. A bed designed to equilibrium capacity has no margin at all, and the failure will arrive as a step change rather than a gradual decline.

Calculating the carbon change-out interval

The arithmetic is short and worth doing before you buy anything. Carbon change-out interval equals carbon mass multiplied by working capacity, divided by the mass rate of pollutant entering the bed — which is inlet concentration times flow times hours operated.

As a worked example: 1,000 kg of carbon at a working capacity of 8% by mass gives 80 kg of usable adsorption capacity. At an inlet concentration of 200 mg/m³ and a flow of 10,000 m³/h, the pollutant load is 2 kg/h, so the bed lasts roughly 40 operating hours. That number tells you immediately whether carbon alone is the right answer, or whether you need a wet stage upstream, a concentration step, or a different device entirely. Run the same sum for the purge case, because the second number is the one that empties the maintenance budget.

Granular vs honeycomb carbon for sticky streams

Granular carbon holds more per unit volume and costs less per kilogram, but it has a higher pressure drop and is harder to clean once the bed surface cakes. Honeycomb carbon has a low pressure drop and resists blinding better on dusty or aerosol-carrying streams, at the cost of lower capacity per unit volume.

On plastic fume the choice usually follows the fouling risk. If the demister and the wet stage are doing their job, granular carbon gives the better economics. If the stream is marginal, honeycomb with a shorter change-out cycle is often cheaper overall than a blinded granular bed that has to be replaced twice as often — see our activated carbon adsorption equipment for both configurations.

The Failure Mode Nobody Designs For: Condensable Wax and Oligomer Fouling

What actually condenses out of plastic fume

Hot plastic vapour leaving a barrel or a die carries more than permanent gases and volatile solvents. It carries a fraction of low-molecular-weight polymer, oligomers, wax, stearate and amide slip agents, and plasticiser — all of which are vapour at processing temperature and solid or semi-solid at ambient.

This is why plastic fume is properly described as an oily and pasty aerosol rather than a dust or a gas. It is material that changes phase inside your ductwork, on your media, and on your instruments.

How fouling kills carbon, UV lamps and heat exchangers

Activated carbon. Condensate deposits on the external surface of the granules and in the macropores. Pressure drop climbs, working capacity falls because pore volume is occupied, and the change-out interval you calculated collapses. A blinded bed can also read normal at the outlet until the day it breaks through in a single step.
UV photo-oxidation. The quartz sleeves are the failure point. A condensate film on the sleeve absorbs the ultraviolet that was supposed to reach the gas. Lamp output is unchanged, but the effective dose delivered to the gas is a fraction of design, so odour removal decays quietly and invisibly.
Heat exchangers on heat-recovery systems. The same film acts as a thermal insulator, so recovery efficiency falls while pressure drop rises.
Sensors and analysers. Sample lines and analyser inlets foul first, which is how a plant can run for months on a monitoring reading that is no longer measuring anything.

The literature on this is thin. Equipment suppliers name the problem — condensable build-up, oily and pasty aerosols — and then move straight to the product list. The mechanism and the design countermeasure are what determine whether the system still works in year three. For more on how adsorption behaves under real conditions, see our notes on the activated carbon adsorption box and on VOC control in scrubber systems.

Design countermeasures that work

Put a demister and a wet stage ahead of the carbon and the UV. This single decision determines whether the rest of the design holds up.
Heat the ductwork where condensate is inevitable and the run cannot be shortened.
Slope horizontal runs to a drain and fit clean-outs and inspection ports at every change of direction.
Choose media and lamp arrangements that can be cleaned in place rather than replaced.
Set the maintenance interval from the measured fouling rate rather than the calendar, and record the pressure drop trend from commissioning day so that you can see it climb.

Choosing a Plastic Waste Gas Treatment System

Selection matrix by resin and process

Polyolefin moulding and extrusion, mixed aromatics, no acid load. Demister, wet cyclone, granular carbon. Add UV only where odour is the driver and concentration is low.
PVC or PVDC. Demister, alkaline wet scrubber in chloride-resistant materials, then carbon. No catalytic route.
ABS and PS with high styrene and strong odour. Demister, wet stage, UV photo-oxidation, carbon polishing.
Polyurethane with isocyanates. Capture is the critical design element; wet stage, then carbon; thermal oxidation only with specialist design.
High-concentration solvent from downstream printing or coating. Consider concentration followed by catalytic or thermal oxidation rather than carbon.
Grinding and regrind dust. A separate dry dust collector with NFPA 660 explosion protection. Never combined with the gas-phase train.

Where the resin mix spans several of these cases, the system is designed for the worst of them or zoned so that different process areas run on separate trains. Where a non-standard combination applies, we build the train to the case — see our customisable wet scrubber range.

What actually drives the cost

Air volume is the first cost driver, and air volume is set at the hood. Over-capturing by 30% costs 30% more scrubber, 30% more carbon and 30% more fan power for the entire life of the plant, so the cheapest hour of engineering is the one spent on the capture survey.

Resin mix is the second driver: a single PVC line turns a carbon-steel system into a corrosion-resistant one. Concentration and required removal efficiency set the stage count, which is why a plant needing only odour control and a plant needing to meet a numeric non-methane hydrocarbon limit do not buy the same system. Operating cost, meanwhile, is dominated by carbon replacement and fan power rather than by the capital cost of the vessels.

Questions to put to every supplier

What capture velocity were the hoods designed to, and how was it verified after installation?
What are the EBCT and bed velocity of the carbon vessel, at what flow rate?
What working capacity was assumed, and what change-out interval does that produce?
What happens to the system during purge, colour change and start-up?
Which wetted materials, against which chloride load and temperature?
What is the pressure drop at end-of-life, and is the fan sized for it?
What monitoring is included, and how is the sample line kept clean?

Compliance and Operation

What to monitor, and how often

Measure the target parameter at the stack, continuously or periodically, together with scrubber liquor pH and dosing rate, and pressure drop across the demister, the packing and the carbon bed. Pressure drop is the cheapest and most honest indicator available: a rising trend on the carbon bed is the early warning of condensable fouling, and it moves months before the outlet concentration does.

Maintenance schedule

Daily. Scrubber pH, dosing pump operation, visible stack condition.
Weekly to monthly. Pressure drop log, drain and clean-out inspection, spray nozzle check and packing inspection.
Periodic. Carbon sampling and outlet testing to establish the real working capacity rather than the assumed one; UV sleeve cleaning or replacement on measured dose rather than elapsed time.
Non-routine events. Purge, colour change and burn-out should have a written procedure and a log, because these are the events that load the system hardest.

Records that satisfy an inspector

The paperwork inspectors ask for is consistent across jurisdictions: the assessment that identified each substance and the control for it, the commissioning data proving the system performs as designed, the maintenance and monitoring history, and evidence that identified defects were corrected on a timeline.

For an export project, agree the record format with the client’s permitting authority at design stage. Sampling ports, monitoring platforms and access ladders are cheap to include in a drawing and expensive to add to a completed stack.

Why Plastics Processors Work With XICHENG EP

What we build

We manufacture the complete train from the hood to the stack: wet scrubbers, cyclone and spray towers, packed absorption columns, activated carbon adsorption vessels and towers, and FRP and PP centrifugal blowers with the ductwork that connects them. Corrosion resistance is our normal range rather than a special order, so PP, PVC and FRP wetted parts are standard on a chloride-bearing stream.

From site survey to commissioning

We start from your resin list, your processing temperatures, your machine layout and your target standard rather than from a catalogue. The design is fixed against measured air volumes and your actual capture points, and the sizing arithmetic behind the carbon bed, the scrubber and the fan is documented and handed over with the system, so that your own engineers can check it and maintain against it.

Documentation and after-sales

Equipment documentation, material certificates and commissioning records travel with every system. Our manufacturing base, testing facilities and certificates are documented on this site — see our certifications and about XICHENG EP — and the after-sales team supports carbon change-out planning, scrubbing liquor control and periodic performance checks for the life of the plant.

Frequently Asked Questions

Is plastic waste gas treatment the same as plastic pyrolysis?
No. Pyrolysis converts waste plastic into fuel gas, oil and carbon black. Plastic waste gas treatment cleans the exhaust air from plastics processing — moulding, extrusion, blow moulding, granulating — before it leaves the stack. The two subjects share a search term and nothing else.

Do I need treatment if I only run polyolefins?
Polyolefin fume is less acutely toxic than PVC or polyurethane fume, but it still carries a condensable aerosol, odour and a non-methane hydrocarbon load that is regulated in most jurisdictions. Whether you need treatment, and to what level, depends on your throughput and the standard that applies to your plant — but you will need capture, and you will have to deal with the condensate.

Why did my activated carbon stop working after a few months?
Almost always condensable fouling. The bed has been blinded by wax, oligomer and plasticiser that passed through the upstream stages. Check the demister and the wet stage before ordering more carbon, or the replacement will fail the same way.

Can one system handle both dust and fume?
No. Combustible plastic dust is a deflagration hazard handled by a dedicated dry collector with explosion protection. Fume is a gas-phase problem handled by washing and adsorption. Combining them creates a hazard inside a vessel and satisfies neither code.

How often does the carbon need changing?
It is a calculation rather than a rule of thumb: carbon mass times working capacity, divided by the pollutant mass rate. Until the working capacity has been measured on your own stream, any quoted interval is an assumption. Start with the calculation and then confirm it by sampling.

Which standard should I design to?
The one that applies where the plant is. Chinese projects typically design to GB 16297, with GB 31572 for resin production and GB 37822 for VOC and fugitive emissions. Export projects design to the receiving country’s standard or to the client’s permit condition. Fix the target before the design, because it determines the stage count.

What does a plastic waste gas treatment system cost?
Air volume, resin mix, concentration and required removal efficiency set the price — and air volume is determined at the hood. Send us your resin list, your capture points and your target standard and we will size the train against your actual conditions rather than a catalogue.

Related Services

Plastics processing is one of six exhaust problems we design for. The others follow the same method — capture first, then a treatment train sized to the chemistry:

Paint waste gas treatment — spray booth and curing oven exhaust, paint mist and solvent.
Electroplating waste gas treatment — acid mist and alkaline gas from plating lines.
Acid mist waste gas treatment — pickling, etching and surface treatment fumes.
Chemical waste gas treatment — multi-component chemical plant exhaust.
Garbage station odour control — ammonia, hydrogen sulphide and organic sulphur from waste handling.

Talk to Us About Your Plastics Line

Tell us which resins you run, at what temperatures, and where the fume is generated. We will come back with a capture layout, a treatment train and the sizing numbers behind it. Contact XICHENG EP to start the survey.