Kemcor Australia

Reduction of Waste from Synthetic Rubber Testing and Unreacted Styrene: Kemcor Australia

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Courtesy of Kemcor Australia

 Kemcor Australia has used cleaner production processes to reduce waste from synthetic rubber testing and unreacted styrene in small batch production, with significant cost savings.

Background

Kemcor Australia is a leader in the production of olefins, poly-olefins and synthetic rubber, and is part of the Altona (Victoria) chemical complex, the largest centre for primary production of petrochemicals in Australia. Bass Strait oil and gas form the feedstock for its operations and the company supplies a large range of products from its three Altona manufacturing sites to the extensive plastics and rubber manufacturing sector throughout Australia. Products manufactured on site, include:

Olefins: ethylene, propylene and butadiene, to meet domestic and overseas demand;

Plastics: polyethylene and polypropylene resins for industries such as packaging, construction and telecommunications;

Elastomers: polybutadiene rubber and styrene-butadiene rubber for many industrial sectors, especially the tyre industry.

The Process

Process 1 Synthetic Rubber Manufacture

To meet customer requirements and quality assurance, testing of the physical properties of synthetic rubber manufactured on the Elastomers site is undertaken in the laboratory area, using specialized rubber-testing equipment.

During testing, heat is generated due to friction between rubber samples and testing equipment. To keep the testing temperature within working limits, process water is used to cool down the testing equipment. Variation in the process water temperature (15 to 35 degree Celsius), combined with thermal mass generation, contributes to periodic product faults giving rise to so-called 'off-specification' products. The rubber waste amounts to 150 tons per year, which is re-processed at a cost of $15,000.

Process 2 Unreacted Styrene

On the Elastomers site, small rubber batches of specialty product are occasionally produced in a batch reactor to consumer requirements. During the manufacturing process, some 2 percent of styrene in latex - one of the raw materials - remains unreacted. This amounts to around 10 tons per year in lost material through fugitive emissions (worth some $10,000). It also poses a risk due to the flammable nature of the styrene vapors.

Cleaner Production Initiatives

In September 1994, Kemcor developed a voluntary Environment Improvement Plan (EIP) in conjunction with the State Environment Protection Authority of Victoria and the Altona community. The purpose of the EIP was to address all environmental issues relevant to the three Kemcor Altona manufacturing sites as a public commitment to continuous environmental improvement. The EIP is to be reviewed and updated every three years.

Process 1 Synthetic Rubber Manufacture

In order to keep the rubber testing equipment within optimum working temperature limits, and to eliminate the use of process water for cooling, a closed-loop cooling system was designed, using mainly equipment found on site, with the main unit being a small mobile compressor-chiller.

The chiller lowers the temperature of the cooling fluid overnight in an attached storage tank, creating the right conditions for testing the next day. The system has been designed to laboratory personnel specifications making it possible to control the flow rate of the cooling agent through the relevant instrumentation, hence controlling the temperature at optimum testing conditions.

Process 2 Unreacted Styrene

In line with cleaner production philosophy, the aim was to reduce waste generation at source. After exploring various options, it was found that by marginally changing the reaction conditions (adding small quantities of extra chemicals to the reactor), the level of unreacted styrene would drop from the existing 2 percent to below 0.1 percent in the final product.

This required the design of a system that would inject quantities of specified chemicals into the batch reactor. The total cost for implementing this change was $50,000.

Advantages of the Process

Process 1 Synthetic Rubber Manufacture

The cooling system exceeded the needs for rubber testing. It has:

  • obviated the need for process cooling water;
  • provided optimum testing conditions while contributing to elimination of 'off-specification' product;
  • improved testing conditions in all laboratory areas, leading to better overall operational performance;
  • reduced waste generation at source in line with cleaner production principles; and
  • contributed savings of $15,000 per year against a total process cost of $25,000, representing a payback period of 20 months.

Process 2 Unreacted Styrene

  • waste styrene reduced from 2 percent to below 0.1 percent in latex feedstock, corresponding to savings of
  • $10,000 per annum (payback period of 5 years);
    risks associated with flammable gas inside the storage tanks reduced;
  • odour on site reduced;
  • waste generation reduced at source;

Cleaner Production Incentive

The cleaner production processes outlined above reflect KemcorĂ­s policy of going beyond environmental compliance and public expectations.

As a leader in environmental performance, Kemcor continuously employs the latest developments in the environmental arena such as Cleaner Production Technologies and techniques to prevent waste and to integrate environmental excellence with product manufacture.

Barriers

No significant problems or obstacles were encountered. The initiatives had the full support of management and staff.

Reference

Case study coordinated by the Environment Management Industry Association of Australia (EMIAA), April 1998.

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