Alkaline Degreasing Detergent

The challenge

A major European manufacturer of exhaust systems for cars and motorcycles contacted us to define a new washing cycle using water-based alkaline detergents. This new process would be used in a new washing system, replacing their current solvent-based system.

Specifically, the client needed to remove neat and emulsifiable oils used for stamping and bending stainless steel and titanium parts. For the client, it was crucial to use an alkaline detergent that was free of VOCs (Volatile Organic Compounds).

The cleaning result had to be absolutely comparable to that achieved with the solvent. Furthermore, they wanted the removed oil to float on the surface of the detergent solution so that it could be extracted and separated by a suitable oil skimmer, thereby extending the solution’s lifespan and reducing disposal costs.

Our Solution

After carefully examining all the types of parts to be washed and their morphology, we concluded that, with all surfaces exposed, the most suitable type of system would be a spray tunnel.

A washing tunnel essentially consists of a corrugated conveyor belt on which the parts to be treated are placed. These parts pass through a series of compartmentalized chambers where individual phases of degreasing, rinsing, and, if required, passivation occur through a hydraulic circuit that feeds a series of spray nozzles. After washing, there are, if needed, blowing and drying stations.

We started by testing several alkaline detergents from our range that were capable of removing the various types of oil present on the parts’ surfaces. To evaluate foaming and oil separation factors, we had to ask the client for samples of the specific oils to assess their behavior and to see if the tested alkaline detergents were capable of not emulsifying them.

After a series of tests in our laboratory and on a small pilot plant, we identified an alkaline detergent that perfectly met all the client’s requirements.

Results

SPRAY TEK 897 was the alkaline detergent that delivered the best cleaning performance.

It is a liquid alkaline detergent that is completely free of VOCs. It was used at a 7% concentration, at a temperature of 70°C (158°F) for a contact time of 150 seconds.

After the degreasing phase, all the washed parts must be rinsed thoroughly with running water and then with demineralized water to ensure that no lime stains remain on the surfaces after the drying phase.

The excess oil removed from the surfaces of the treated parts does not emulsify with the detergent; instead, it floats to the surface, allowing the oil skimmer to separate it. This ensures consistent washing quality over time and optimizes the operating costs of the system.