PVC / VINYL COATING - Indirect heated oven and no lacquer or chlorinated additives

PROCESS INFORMATION
Most common manufacturing applications are Synthetic Leather ( car upholstery, bags, shoes etc.), vinyl coated and linoleum flooring, vinyl coated wallpaper, laminated sheets ( special films, belts, tarpaulins ) and foam products.

Polyvinyl-chloride (PVC) is a thermoplastic and is mixed to additives which improve its properties and enable it to be processed more easily.

Most common major additives are:
 plasticizers to provide elasticity i.e. DOP (Dioctyl Phthalate)
 stabilizers to prevent degradation i.e. PB salts
 lubricants (solvents) to prevent plugging on cylinders of the calendering machine
 charges i.e. silicium
 pigments i.e. anthraquinones

Typical formulation : PLASTICIZERS : 50%
SOLVENTS : 48%
OTHERS : 2%


The emulsion (polymer + additives) is spread coated and heat cured or calenderized in ovens. PVC emulsion is fed to ovens with successive steps of curing/calendering and cooling sections. Gas is extracted from curing/calendering sections and cooling sections.

Exit gas from curing ovens (180°-150°C) which has been directly or indirectly heated.

Depending upon formulation, 500 to 5,000 mg/m³ of plasticizers are present in the exhaust gas. Solvents and other products are also entrained.

PROBLEMS TO SOLVE
Air pollution. As an average, industrial sites regulations specify a maximum emission of 20 mg/m³ of plasticisers ( = invisible ), or 50 mg/m³ total carbon, or an odour related limit. More stringent levels, e.g. 2mg/m3 of DOP plasticiser are now sought.

Recovered plasticizer and solvent could be re-used.

DESIGN SOLUTION
1. Basic BECOFIL System - Indirect Heated Ovens
No lacquer or chlorinated parafins

There are 4 main feature components in this system design :
 An efficient prefilter (type BECOIL) is installed to collect large particles and insolubles, to give maximum protection to the downstream components to maximise their life and minimise maintenance.
 It is usually necessary to fit a water fed fin & tube heat exchanger cool down the gas to 35°C to ensure all plasticizers and the less volatile solvents are in liquid phase.
 High efficiency filters Type HT(2) TGW15 are used, giving the ultimate in sub-micron fume collection.
 Bag liners are fitted inside each candle filter to give final added protection to the fibre ( which is the most expensive component )

Additional features are :
 Pre-filter and Bag Liners can be cleaned and reused when pressure loss indicates solids blockage.
 Pre-filter fitted via a drawer system, for easy access.
 Candle Filters are fitted via removable flat roof sections for easy access to the Candle Filters and Bag Liners.
 Drains allow recovery of liquid.
 Hot water heat recovery from the Heat Exchanger can be used in the plant.
 The filter supports and the system structure are manufactured from inexpensive Carbon Steel.

Options :
 Horizontal pre-filter housing and cooler for smaller air volumes or downward flow vertical pre-filter housing and cooler for larger air volumes.
 Candle Filter lengths from 1220mm to 3660mm, to suit available height above vessel, or to minimise system footprint.
 For some installations where the highest possible efficiency is demanded, we have installed a concentric double fibre bed candle filter design, which can achieve 5 to 10mg/NM3 exit.
 If no corrosive components are present, cooler will be Copper tubes & Aluminium fins. Alternatively, Carbon Steel or Stainless Steel tubes can be used.





Other Applications
ASPHALT CHLORINE PRODUCTION - WET CHLORINE CHLORINE PRODUCTION / DRY CHLORINE CHLORINE PRODUCTION / HYDROGEN STREAM CHLORINE PRODUCTION / NaOH STREAM COMPRESSED GAS / AIR DETERGENT SULPHONATION / AFTER THE SULPHONATION REACTOR DETERGENT SULPHONATION / BEFORE THE SULPHONATION REACTOR DETERGENT SULPHONATION / HOW ‘STAR’ CANDLES EFFICIENTLY HANDLED HIGH MIST LOADS, SAVING ENERGY AND COST HYDROCHLORIC ACID NITRIC ACID / INLET AIR AND NH3 FILTERS,NITRIC ACID / INLET AIR AND NH3 FILTERS NITRIC ACID / PLATINUM CATALYST OR PALLADIUM DUST RECOVERY NITROGEN FERTILISERS / AMMONIUM NITRATE – NEUTRALISER & EVAPORATOR NITROGEN FERTILISERS / AMMONIUM NITRATE – PRILLING TOWER NITROGEN FERTILISERS / AMMONIUM NITRATE PRILLING TOWER – SELECTIVE FILTRATION OF ONLY MOST HEAVILY CONTAMINATED AIR NITROGEN FERTILISERS / UREA – PRILLING TOWER NITROGEN FERTILISERS / UREA –EVAPORATOR NITROGEN FERTILISERS / UREA PRILLING TOWER DEMISTERS & COALESCERS FOR LOW PRESSURE LOSS FILTRATION AND CONCURRENT NH3 ABSORBTION. NON-FERROUS METALS PRODUCTION - Process Tanks OIL REFINING - FCC Fractionator and Pipestill PHOSPHATE FERTILISER PRODUCTION - P2O5 Separation from Phosphate Slurry PHOSPHATE FERTILISER PRODUCTION - Reactor Tanks PHOSPHORIC ACID / P2O5 FILTRATION SYSTEMS PHOSPHORIC ACID / WAGON LOADING - FUGITIVE EMISSIONS CONTROL PVC / VINYL COATING - Direct heated oven / Indirect heated oven +lacquer / chlorinated additives SO3 / OLEUM TANK VENTS SULPHURIC ACID / ACID CONCENTRATOR SULPHURIC ACID / ACID DISTRIBUTION SULPHURIC ACID / CROSS FLOW STRIPPER SULPHURIC ACID / DRYING TOWER SULPHURIC ACID / FINAL ABSORBTION TOWER IN SPENT ACID PLANTS SULPHURIC ACID / FINAL ABSORBTION TOWER OR SINGLE ABSORBTION TOWER SULPHURIC ACID / HEAT RECOVERY DESIGN PLANT INTERMEDIATE ABSORBTION TOWER SULPHURIC ACID / INTERMEDIATE ABSORBTION TOWER SULPHURIC ACID / Mercury Removal Tower SULPHURIC ACID / OLEUM UPSTREAM OF INTERMEDIATE ABSORBTION TOWER OR FINAL ABSORBTION TOWER OR SINGLE ABSORBTION TOWER SULPHURIC ACID PLANT SO2 TAIL GAS / NH3 / SO2 TAIL GAS SCRUBBING TOWER