Asphalt recovery system and process

摘要

An asphalt recovery system may include an extractor, a desolventizer, and an evaporator. During operation, the extractor may receive a solvent and roofing waste and extract asphalt from the roofing waste with the solvent. The desolventizer may receive a solvent-wet solids stream from the extractor and vaporize solvent from the solvent-wet solids stream to yield desolventized solids. The evaporator may receive an asphalt-rich solvent stream from the extractor and vaporize solvent from the stream to produce a solvent stream and an asphalt stream. By configuring the evaporator to operate at a pressure above atmospheric pressure, the boiling point in the evaporator may increase as compared to operating the evaporator at a pressure below atmospheric pressure. In turn, this may keep the viscosity of asphalt within the evaporator less than 500 centipoise, which may improve heat transfer to the asphalt and prevent that asphalt from plugging the evaporator.

主权项

1. An asphalt recovery process comprising:
extracting asphalt from roofing waste with a solvent in an extractor to form an asphalt-rich solvent stream and solvent-wet solids stream; processing the solvent-wet solids in a desolventizer at a pressure below atmospheric pressure to vaporize solvent from the solvent-wet solids stream and yield desolventized solids; and vaporizing solvent from the asphalt-rich solvent stream in an evaporator, wherein the evaporator is operated at a pressure above atmospheric pressure so as to increase a boiling point of the solvent as compared to operating at a pressure below atmospheric pressure and so that a viscosity of asphalt within the evaporator is less than 500 centipoise.