Disposal of wastes with solvent recovery

A process for recovering solvents from a fluid sludge waste containing solvents and non-volatile matter, comprising,

• continuously feeding hot granular sand into an inlet end of an enclosed blender-flasher vessel,
• feeding said fluid sludge waste into said vessel to contact said hot granular sand,
• continuously blending said hot sand and fluid sludge waste in said vessel,
• flashing off volatile matter comprising solvents, in said fluid sludge waste in said vessel, and forming a dirty sand in said vessel comprising said hot granular sand coated with non-volatile matter from said fluid sludge waste,
• advancing said dirty sand through said vessel towards an outlet end,
• removing the flashed off volatile matter from said vessel, condensing it and recovering the solvents from the condensate, and feeding the dirty sand from said vessel to a reactor.
• supplying air to said reactor,
• thermally decomposing said non-volatile matter of said dirty sand in said reactor to produce pyrolysis gases and a cleansed hot sand in a thermally self-sustaining reaction effective to maintain the heat need of the process,
• recycling the cleansed hot sand to the feed to said blender-flasher vessel, and
• recovering the pyrolysis gases and burning them to provide heat externally of the process,
• the feeding rate of the hot sand and dirty sand and the recycling rate of the cleansed hot sand being controlled to provide a continuous circulation of the sand, said supply of air to said reactor being effective to maintain said thermally sustaining reaction with heat developed in the thermal decomposition of said non-volatile matter of said dirty sand.

A process for recovering solvents from still bottom sludge with development of a source of heat comprising:

• continuously feeding hot granular sand having a particle size of 0.5 to 1.5 mm into an enclosed blender-flasher vessel having an inlet end and an outlet end,
• advancing said hot granular sand in said vessel from said inlet end towards said outlet end, said sand being maintained at a temperature in the range of 250.degree. C. to 470.degree. C.,
• continuously feeding a fluid still bottom sludge into contact with said hot granular sand adjacent said inlet end,
• continuously blending said hot sand and fluid still bottom sludge in said vessel,
• flashing off volatile matter comprising solvents, in said fluid still bottom sludge, in said vessel, without cracking and thermal degradation of non-volatile matter in said still bottom sludge, and forming a free-flowing, noncaked dirty sand in said vessel, said dirty sand comprising granules of said hot granular sand coated with said nonvolatile matter from said still bottom sludge,
• advancing said dirty sand through said vessel to said outlet end without cracking and thermal degradation of said non-volatile matter,
• removing the flashed off volatile matter from said vessel, condensing it to form a condensate and recovering solvents from the condensate,
• feeding said dirty sand from said vessel to a reactor,
• thermally decomposing said non-volatile matter of said dirty sand in said reactor to produce pyrolysis gases and a cleansed hot granular sand,
• recycling the cleansed hot sand to the feed to said said blender-flasher vessel, and
• recovering the pyrolysis gases as a source of heat energy.