Abstract: The undesirable and damaging reaction heat occurring during the blowing of asphalt is avoided by injecting water into the air inlet pipes of the reactor vessel heated by the hot asphalt surrounding them. During this, the superheated steam produced without expenditure is passed through the liquid asphalt, causing the removal of low molecular hydrocarbons formed during the blowing or stripping.

Abstract: The production of normal and premium lube grade blending stocks of 100, 300 and 700 second neutral material along with high boiling by-product material for the manufacture of asphalts is improved by using a low pressure vacuum tower provided with an overflash separation in the tower bottom from resid.

Abstract: A bitumen blowing method comprises blowing air into a body of bitumen to produce an upward flow of bitumen relatively rich in air and a downward flow of bitumen relatively poor in air. The upward flow is agitated to disperse the air therein. A bitumen blowing reactor suitable for carrying out the method comprises a reactor vessel having an air inlet, a dispersion container in the vessel, the dispersion container having a floor provided with a passage therethrough, and bitumen-agitating means disposed in the container. The air inlet is arranged to discharge below the passage. One or more additional dispersion containers each having bitumen agitating means disposed therein may be provided above the first-mentioned container.