PVC / VINYL COATING - Direct heated oven / Indirect heated oven +lacquer / 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
BECOFIL System with ‘Scrubber’ Pre-filter -
Direct Heated Ovens
Lacquer or chlorinated parafins
Low volatile solvent removal

In response to the special problems presented by the very dirty fume which is usually
generated by direct fired ovens, we developed a simple solution to avoid ( or at least
minimise) the blockage by hydrocarbons, ‘cracked’ hydrocarbon compounds and
other solid / viscous materials, including chlorinated parafins such as Cereclor
( which forms a waxy film on the Candle Filters when cool ) and lacquers ( which
form a hard coating on the Candle Filters when cool ) .

We have developed a pre-filter scrubbing section, which can be a first stage add-on in any emission treatment line. Such pre-filter scrubbers are working perfectly at various sites in Europe.

A low pressure loss BECOIL demister pad is irrigated with recirculated DOP or other suitable plasticiser which is used in the customer’s process. This creates an efficient, high voidage contact bed to knock out particulates and viscous materials, before they pass to the main Candle Filter vessel.

This is done in a downward flow, vertical arrangement and washes solid or coated materials out of the pre-filter and the cooler below it.

In addition to the same 4 main feature components in the basic system design this enhanced design advantages are :
 However ‘dirty’ the service, the scrubbing section gives maximum protection to the downstream components to maximise their life and minimise maintenance, without reducing the system filtration efficiency.
 Using plasticiser as scrubbing liquid, avoids the use of chemicals which are not ‘natural’ to the process and avoids the use of water which creates an effluent problem.

Additional features are :
 Same as for the Basic System

Options :
 In addition to the 1st stage pre-filter in the vertical housing, 2nd and 3rd stage pre-filters can be fitted ( drawer access also ) in the inlet section of the main Candle Filter vessel, to give extra pre-filtration and fibre bed protection in the most ‘dirty’ services.
 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.
 Cooler will be Carbon Steel or Stainless Steel tubes & Aluminium fins.





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 - Indirect heated oven and no lacquer or 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