A method and process device for recycling waste high boiling point heat transfer oil

Abstract

A method for recovering waste high-boiling-point heat-transfer oil comprises the steps: 1, pre-processing waste heat-transfer oil; 2, performing hydrogenation refining on the waste heat-transfer oil pre-processed in the step 1; and 3, performing fractional distillation on the waste heat-transfer oil subjected to hydrogenation refining in the step 2. Concretely, fractional distillation in the step 3 is performed according to the following steps: 1), enabling liquid-phase oil separated out from hydrogenation low-pressure separation composition to enter a reduced-pressure flash-evaporation tower, cooling a gas phase getting out from the top of the reduced-pressure flash-evaporation tower by a condenser, and enabling the cooled gas phase to enter a reflux tank at the tower top, pumping and exhausting the gas phase into atmosphere, pumping out a liquid phase via a reflux pump and taking the liquid phase as naphtha and sending to a storage tank; and 2) pressurizing falling-film distillation tower bottom distillates and conveying to a reduced-pressure distillation tower by a conveying pump, cooling a gas phase getting out from the top of the reduced-pressure distillation tower by a condenser and enabling the cooled gas phase to enter a reflux tank at the tower top for oil-gas separation, enabling the liquid phase to be as reduced-pressure tower-top oil and enter a condenser for cooling, one branch of the reduced-pressure tower-top oil is used for column-plate refluxing, one branch of the reduced-pressure tower-top oil is used as 7# white oil and conveyed to an irrigated-area storage tank for self use and export sale, and one branch of the reduced-pressure tower-top oil is used 15# white oil and conveyed to an irrigated-area storage tank for self use and export sale. The method has the characteristics of low energy consumption, cleaning, environmental protection, high economic benefit economic benefit and high yield.

Description

technical field [0001] The invention belongs to the technical field of heat transfer oil recovery, and in particular relates to a method for recycling waste high boiling point heat transfer oil, which uses high vacuum molecular distillation technology to recycle the waste high boiling point heat transfer oil. Background technique [0002] Heat transfer oil is a kind of heat transfer medium. It has been widely used in recent years because of its characteristics of uniform heating, accurate temperature adjustment and temperature control, high temperature under low steam pressure, good heat transfer effect, energy saving, convenient transportation and operation, etc. In various occasions, and its use and dosage are increasing. After long-term use of heat transfer oil, due to coking, decomposition and other reasons, the thermal conductivity decreases, and it will eventually become waste heat transfer oil. Discarded heat transfer oil can be used as fuel oil for combustion in ref...

AI Technical Summary

Problems solved by technology

This recovery method has a long operation process and needs to go through multiple washing processes, and will produce acid-base neutralized salts, decolorizers, and white clay residues, which will cause serious environmental pollution.

Moreover, due to the high boiling point of the heat transfer oil, the rectification method consumes a lot of energy and the product yield is low

In addition, due to the large differences in the indicators of different types of heat transfer oil, waste heat transfer oil has different sources, and the above recycling method will also cause unstable product quality