Processing Diesel Fuel From Waste Oil

Abstract

There is disclosed a system and method for processing diesel fuel from petroleum-based waste oil on a small scale compared to conventional methods for re-refining waste oil to a valuable product. In an embodiment, the method comprises dehydrating waste oil to remove water from the waste oil, and operating a vertical cylindrical reactor to induce pyrolysis of the dehydrated waste oil and convert it into a hydrocarbon vapour phase. The hydrocarbon vapour derived from pyrolysis is condensed and distilled using a distillation tower to produce diesel fuel, heavy liquid hydrocarbon, light liquid hydrocarbon and light hydrocarbon vapour. A filtering step cleans the processed diesel fuel to obtain a clean diesel fuel product.

Description

[0001]The present invention relates generally to the field of re-refining or reprocessing petroleum-based waste products, and more particularly to an apparatus and method for processing diesel fuel from waste oil in a micro-scale processing facility.[0002]The present invention also pertains generally to thermal conversion of waste oil in a vertical cylindrical reactor but more particularly it relates to an apparatus or device for pyrolytic or thermal conversion of waste oil where waste oil is heated and decomposed into smaller hydrocarbons inside a pyrolysis device, comprising a reactor, a heater shell and a burner mechanism.BACKGROUND[0003]Historically, re-refining waste oil has been difficult to undertake economically unless conducted on a large scale. While complex large scale processing facilities for recycling waste oils and converting them to reusable products are known, due to the expense of the known technologies, these large-scale capital intensive process facilities are re...

AI Technical Summary

Benefits of technology

The present invention is a system and method for producing diesel fuel and diesel-like products from petroleum-based waste oil in a micro-scale processing facility. The system includes a vertical cylindrical reactor designed with a maintenance access way, a feed point, exit point, and related equipment and instrumentation control to obtain optimum conditions that provide an uninterrupted flow of high yield petroleum distillates, primarily in the diesel fuel range, with a minimum coke production without the use of catalysts. The system operates on a continuous basis, reducing the need for multiple reactors or operation in batches. The invention achieves this through an optimum residence time under sub atmospheric pressures during the pyrolysis reaction. The reactor does not require a high frequency of cleaning nor does it require the installation of a bleeding pump or a scrapper like apparatus to continually address the formation of coke inside the reactor. The device also achieves a very high yield of diesel fuel range hydrocarbons from the present invention. The system and method can be viably incorporated in a re-refining facility and are particularly suitable for smaller markets that cannot support large-scale refining facilities.

Problems solved by technology

Historically, re-refining waste oil has been difficult to undertake economically unless conducted on a large scale.

While complex large scale processing facilities for recycling waste oils and converting them to reusable products are known, due to the expense of the known technologies, these large-scale capital intensive process facilities are required to draw on large geographical catchment areas for waste oil feedstock.

Due to feedstock, transportation, and logistics costs, which may quickly consume any economies of scale benefit, large scale processing facilities are only viable in large regional markets able to supply sufficient quantities of waste oil feedstock within a reasonable distance.

In smaller and developing markets where such large scale operations are not sustainable, it has not been possible to economically re-refine waste oils with known technology.

Current practices in markets too small to support conventional re-refining facilities include burning waste oil as a dirty fuel for industrial use or space heating, or alternatively disposing of large volumes of waste oil in potentially environmentally inappropriate ways.

These practices may result in a discharge of air borne pollutants, or contamination of soils and groundwater.

Whichever practice is used, the resulting water, soil, and / or air pollution contains many of the harmful chemicals found in waste oil, which may expose plants, animals and humans to their toxic effects.

However, the existing technologies have failed to address the needs for re-refining in small population centres.

They have failed to create a continuous and economically viable process.

These re-refineries have also failed to address low yield and the formation of coke sludge in the processes.

However, this design element ensures that the sludge / coke forming material spends a lot of time near the hottest part of the reactor resulting in increased coke formation.

As a result significant operating and maintenance costs are incurred and loss of production is suffered for the removal and disposal of coke and other heavy by-products.

A number of approaches have been developed to attempt to overcome the coke formation issue and the resultant difficult to control operation.

The heavy fuel oil stream is withdrawn at a rate of approximately 25% of the inlet feed rate and thus significantly reduces the overall process yield to diesel fuel.

An improvement on the process and / or device is claimed in U.S. Pat. No. 7,255,785 issued to Kong and Jeong but it is still a semi-continuous process, results in solidifying sludge cake which must then be removed by means of a bleeding valve at the bottom of the vessel and the process results in only 70 percent conversion of feedstock.

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