Concept engineering for a cooling water treatment of an aluminum cable factory (LA28)

ISSUE

A plant located in Quebec (CA) operates a manufacturing process for aluminum cable. The cables are molded continuously and directly wound on a spool. To do this, the cable must be quenched and cooled very quickly from 350-400°C to 80-150 ° C using a cooling water emulsion or a coolant. This coolant is an emulsion composed of water and mineral oil filtered and cooled in a closed circuit.

The plant uses a gravity filter to filter coolant contaminated with aluminum particles, tramp oil and other process contaminants. Since this equipment can filter only 20% of the liquid flow, an accumulation of solids and tramp oil occurs in the circuit which causes the clogging of the injection nozzles and the contamination of the aluminum cable. When the solution becomes too contaminated, a purge of the system is performed to remove solids and tramp oil, resulting in costs that could be avoided with a more efficient filtration system.

TECHNOLOGICAL CHALLENGE

STS Canada needed to identify and size the most suitable filtration technology for the coolant. The available footprint being extremely small, the system had to be able to handle the entire flow of coolant while being as compact as possible. In addition, the quality of the filtrate obtained should be clear enough so that no purge of the system is necessary within 2 years of operation intervals.

RECOMMENDED SOLUTION

STS Canada first established with the customer the list of design criteria that the selected technology had to meet. Subsequently, the various filtration technologies available on the market were evaluated using the previously established design criteria and internal tools developed by STS. Then, laboratory tests were conducted in order to collect the necessary information required for proper sizing of the selected technologies. Once sized, quotes were requested from various manufacturers available in the STS database to identify the supplier offering the most economical and compact technology suitable for this application. Finally, a general arrangement drawing of the proposed system was created in order to present the layout of the different equipment of the system.

RESULTS

Following STS Canada's intervention, a concept using an hydrocyclone bank combined with a continuous vacuum filter was proposed to replace the gravity filter. This concept had the advantage of allowing the treatment of the entire flow of coolant while using the same footprint than the one used by the current gravity filter. A modification of the operating philosophy of the feed tank also made it possible to address the issue of free oil. In addition, thanks to STS Canada's supplier databases, the manufacturer offering the best-value equipment has been identified and presented to the customer.