Bitumenous paints from refinery sludge

This paper reports the data obtained on an attempt at the utilisation of the oily sludge, which is a dumped waste of petroleum refineries. Growing public concern over the health and environmental implications of these wastes has forced the regulatory agencies to make it mandatory for these industries to undertake the disposal of these wastes in an effective and environmentally safe manner. In the present work, the above sludge after purification was subjected to vacuum distillation to recover approximately 17% of lighter oils. The residue was subjected to heat treatment at 225°C for 2.5 h with ‘2.5% w/w AlCl3’ to obtain industrial bitumen 90/15 grade (Industrial bitumen are of different types depending on the softening point–penetration relationship. The first figure 90 represents the softening point while the second figure 15, represents the penetration. Both penetration and softening points are a measure of consistency for bitumen). The usefulness of the above industrial bitumen was tried in the preparation of bituminous paints. All three formulations investigated were found to be homogeneous showing no separation of solvent. There was no coagulation of the asphalt base nor settling or packing in the container. These samples were found to meet the requirements of drying time, consistency, finish, stripping, flexibility and adhesion, keeping properties, etc. It was also seen that the heat resistance of these bituminous paints can be increased considerably by including cashew nut shell liquid–formaldehyde resin in the formulation. Cashew nut shell liquid (CNSL) is a cheap by-product of the cashew industry, and its utilisation can also help to reduce production costs of bituminous paints. This study also showed that incorporation of chlorinated rubber in the formulation would enhance the acid resistance considerably without affecting heat resistance and other desirable properties. This method of using sludge as bituminous paints can be a simple, eco-friendly and useful means of disposal in petroleum refining industries.