Reducing solvents in a company that produces plastic coated textiles

Norway

1992

Full scale

MANUFACTURE OF CHEMICALS AND CHEMICAL PRODUCTS # 31

Background:

The Norwegian textile company featured in this case study, produces plastic coated textiles by the meter to be use for clothing. The company has 155 employees, and a turnover of 172 million NOK.

During the production of plastic coated textiles, the fabric is impregnated and/or coated with polyvinyl chloride (PVC) and polyurethanes (PUR)   in a plastic-coating process and in a drip-impregnation process. The waste gas from the drip impregnation, white spirit and dioctylpthalate, are released as air emissions. The emissions are taken to the after-burning unit from which CO2, SO2, H2O and small amounts of hydrocarbons are emitted. When the machines are cleaned a lot of solvents containing methylethylketone and white spirit are used.

After the pigment containers are cleaned, the remaining pigments and white spirit are collected in separate tanks where the pigments settle. White spirit can be reused many times. Some of the sediments are dried and the solvents are burned in the after burning facility, the rest are disposed of as a special waste.Washed clothing and other things that contain solvents are put into a drying room where the vapor goes into the afterburner furnace.

Other wastes include: material scraps, cardboard, paper, woodwork and other kinds of production waste. The wastes from the production are delivered to the municipal waste dump, and the special wastes are delivered to Renor AS, in Aurskog, Norway.

The company wanted to further educate its employees and implement cleaner production in the production processes.

Cleaner Production Principle:

Recovery, reuse and recycle; Material substitution; Process modification

Cleaner Production Application:

The following CP options were reviewed at the facility, and the stage of implementation and level of commercialization of any involved technology noted.

  1. Recycling of methylketone (MEK) and toluene by distillation. The option was started in October 1992. A distillation apparatus of the type "Formeco" takes care of all the solvents which are used for cleaning. About 95 percent can be recovered.
  2. Recovering of solvents from the coating line. The process was found through a search in a database. It is patented though not in practical use.
  3. Recycling of white spirit and dioctylpthalate (DOP) from the impregnation unit. The option was put on hold until the company could perform additional testing. The project group did not find any solutions for recycling of white spirit and DOP. Then they looked for solutions for combustion of the solvents. The process identified uses catalytic oxidation, which combusts the solvents with a minimum concentration of 2%. At lower concentrations propane is used as combustion help.
  4. Source-sorting of waste from the production and optimal utilization of the waste fractions. With the help of a sanitation company, they began to sort cardboard and paper, woodwork, and waste from production. Source sorting can be started up by the following systems:
       
Cardboard and paper can be delivered as 2 separate fractions or as one fiber fraction.
Woodwork is used by the employees as firewood.
Other kinds of combustible materials are delivered to the municipal waste dump.
Other kinds of waste from offices, storage and production units are dumped on the waste dump.
  1. Source-sorting of office waste. They began by placing 85 cardboard boxes to collect scrap paper. Each office space is equipped with a cardboard box to collect paper, and there are 120 liters plastic bins with wheels by the copy machines and printers. Recycled paper is collected. When external recycling of empty barrels was not possible, the problem was minimized by the help of a barrel press.
  2. Recycling or minimization of empty barrels and used metal packaging. A barrel press was bought in 1992 and every barrel is pressed after it is cleaner and put into the container.
  3. Use of water soluble plastic materials in the coating line. The first plastic materials were tried out and the results increased the interest from the company. The company is using water solvable plastic materials in the coating line. The limiting factor to expanding the practice has been the limited quality of substitutes available.
  4. Use of water soluble plastic materials in the impregnation unit. This option was not tried out.
  5. Connecting the ventilation from the impregnation installation to the after burner installation. When the project was started, the after burner furnace consumed all the air from the coating line and the machine hall. Experiments with the connection of suction from the impregnation unit were carried on throughout 1992. The results show that the conditions from the coating line and the after burning furnace should not be "disturbed" by extra air containing VOC. When experimenting with the suction installation from the coating line and the machine hall, they found out that the connection of the impregnation installation to the system would make problems.
  6. Catalytic oxidation of white spirit and DOP from the impregnation.

Environmental and Economic Benefits:

           
Recycling of washing thinner by distillation gives a reduction of consumption of MEK and toluene of about 13,000 liters per year.
Recycling of solvents by distillation result in 12,000-13,000 liters of less special waste.
A possible start of a catalytic oxidation of white spirit and DOP will give a yearly reduction of emission to the air of about 1700 kg white spirit and 3 kg DOP.
There are no particular changes in the production volume or the water and energy consumption.
Source sorting of waste from the production (cardboard, paper and woodwork), will reduce the waste streams with 30-50 tons per year. Source sorting of paper from the offices, will reduce the waste stream with 8-10 tons per year.
The waste to the municipal waste dump is reduced by about 30-50 tons per year. The special waste is reduced by about 60 % or 12,000 liters per year.

Investment costs were:

     
distillation installation, 40,000 NOK,
catalytic combustion installation, 300,000 NOK, and
barrel press, 16,500 NOK.

Operational and maintenance cost figures include:

     
reduced costs for special waste of about 120,000 NOK per year,
reduced waste costs by 20,000 NOK per year because the paper and cardboard are recycled, and
reduced waste costs because the barrels are compressed.

The recycling of MEK and toluene had payback time of 0.8 years. The barrel press had a payback time of 1.6 years.

Constraints:

None reported.

Contacts:

State Pollution Authority,
Att: Uno Abrahamsen, Postboks 8100 Dep., 0032 OSLO, Norway
Tel : + 47 22 57 34 00
 
Oestfold Research Foundation,
Att: Arild Olsen, Postboks 276, 1601 FREDRIKSTAD, Norway
Tel : + 47 69 34 19 00
 
Helly Hansen AS,
Att: Operating manager Jan Erik Andersen, Solgaard Skog 139,
1500 MOSS, Norway
Tel : + 47 69 24 90 00

Review Status:

This case study was translated from Norwegian and submitted to UNEP IE on behalf of the Norwegian State Pollution Control Authority by Stiftelsen Ostfoldforskning in February 1994. It was reviewed and edited by UNEP IE in July 1995. It has subsequently undergone a formal technical review in September 1998 by Dr. Prasad Modak, Environmental Management Centre, Mumbai, India..