EP2011848B1 - Method for stabilising heating oil or diesel oil, particularly from depolymerisation of residue containing hydrocarbons, or pyrolysis oil - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to a method having the features of the preamble of claim 1. Thereafter, the invention first relates to a process for stabilizing fuel oil and diesel oil, which, in particular after depolimerizing hydrocarbonaceous residues, was obtained by fractional distillation .. In addition, the method is used for stabilizing of pyrolysis oils, so that they can be used after the stabilization process as a fuel in heavy oil-powered units (machines).

TECHNOLOGICAL BACKGROUND

By Depolimerisation of hydrocarbon-containing residues obtained heating and diesel oil is from the DE 10 2005 010 151 B3 known. The Depolimerisation of hydrocarbonaceous raw materials takes place in that the raw material, such as plastic or waste oil, in a reactor heated to nip temperature in liquid or pulpy consistency is injected under pressure in a preheated state. From the indirectly heated over the jacket surface, for example, 420 ° C internal temperature reactor, a vapor fraction is withdrawn, from which by fractional distillation directly a diesel or Heizölfraktion is obtained. The solid obtained in the reactor is continuously withdrawn and processed. It has been found that, especially in this recovery process for fuel oil and diesel oil results in an initially very clear product, which, however, colors after some time until it looks almost black. Although this does not affect the usability as a diesel fuel or heating fuel, such a coloration of the product is not accepted by the customers.

In the case of engine oils, an increase in viscosity, which may also be associated with darkening, is known due to a so-called oil oxidation, for which, however, there is no oil treatment. Rather, the exchange of so changed oils is propagated. For motor fuels, especially when prepared by cracking or pyrolysis, storage stability can be improved by adding antioxidants, such as those known under the trade name "Kerobit" from BASF. This is intended to inhibit the polymerization reactions promoted by free radicals at the ends of hydrocarbon chains. Such additives are usually hazardous to health.

In pyrolysis, especially of rubber and other renewable resources, a pyrolysis oil is produced. Pyrolysis is the heating of organic substances with the exclusion of oxygen. Delimits the pyrolysis against a thermolysis undertakes M.Krapf in Z. Angew. Chemistry 98, 1986, 413-429 , The pyrolysis process takes place in the case of so-called high-temperature pyrolysis at temperatures between 600 ° C and 800 ° C. The product oil (pyrolysis oil) produced in this way has the same problem as products obtained by depalimerization, because even the pyrolysis oil is darkened by the presence of unsaturated hydrocarbons.

In order to make it suitable for use in heavy-duty engines, a further process step is necessary.

US-A-3597173 discloses a method of stabilizing petroleum distillates boiling between 24 ° C and 399 ° C, greatly reducing rubber formation during storage. The process involves the formation of soluble and insoluble gum and sludge by oxidation and / or peroxidation; then separation of insoluble gum and sludge by sedimentation, centrifugation or filtration; and then depressurized distillation or vacuum distillation to remove the soluble gum and sludge.

GB839552A discloses a method of stabilizing petroleum distillates boiling between 38 ° C and 649 ° C, preventing gum formation during storage. The process involves irradiating the petroleum distillate in the presence of an oxygen-containing gas to form soluble and insoluble gum and sludge; and then a separation of soluble and insoluble gum and sludge in a distillation step.

PRESENTATION OF THE INVENTION

Based on this, the object of the invention is to remove the dark coloration of diesel and heating oil, in particular if it has been obtained by depolimerization of hydrocarbon-containing residues, or of pyrolysis oil in a simple way. In particular, complex hydrogenation processes should be avoided. To solve this problem, it is proposed to first allow darkening of the diesel, heating or pyrolysis oil (hereinafter also referred to as the starting oil), in particular under oxygen access, and subsequently to transport the darkly colored starting oil to a distillation or redistillation (hereafter also referred to as Entfärbungsdestillstion) to undergo. It has been found that this process produces a bright and clear product without turbidity and keeps this product clear and bright in the long term. Property values of a diesel fuel according to DIN EN 590 and property values for heating oil in accordance with DIN 51603 /, could be achieved in this way, at least insofar as the sulfur contained was reduced to corresponding limits.

The coloring process of the starting oil can largely be prevented or slowed down considerably if the starting oil is stored, for example, under protective gas and / or in the dark in a tank, preferably with the exclusion of air and not too high temperatures. The aging or inking process then proceeds very slowly, or is stopped. If, for example, you allow air to enter a source oil tank, it may take a few weeks, for example 2 or 3 weeks, until a clear color change occurs. So it may be useful, the fresh produced starting oil appropriate to lagging in order to delay the aging process.

To accelerate the treatment of the starting oil according to the invention, an oxidative treatment, e.g. performed with air. When the starting oil is e.g. if the air flows through it, the dark color can be set in a few seconds.

The Enrfärbungsdestillation can be carried out in a so-called thin-film evaporator. In the thin-film evaporation, the discolored starting oil is passed in a vacuum-maintained thin-film evaporator as a thin layer over about 180 to 240 degrees C, preferably at 200 to 230 degrees C hot evaporator surface and then condenses the resulting vapor component in particular as diesel or fuel oil , The thin-film evaporation takes place under a pressure of absolutely about 1 to 500 mbar, preferably from 2 to 100 mbar.

By the invention, u. a., Unexpectedly high levels of discolored starting oil are achieved as a permanently clear product.

The same procedure with the same process parameters can thus be used both in the decolorization of diesel or heating oil and in the decolorization or purification of pyrolysis oil, even in the latter a clear coloration of the pyrolysis oil is achieved and the useful product thus produced is usable in internal combustion engines. It stays clear for a long time.

The abovementioned and the claimed components to be used according to the invention described in the exemplary embodiments are not subject to any special conditions of exception in terms of their size, shape design, material selection and technical conception as well as the other process conditions, so that the details given in US Pat Application field known selection criteria can fully apply

Further details, features and advantages of the subject matter of the invention will become apparent from the dependent claims, as well as from the following description of an embodiment of recovered by depolymerization heating oil with subsequent bid distillation by thin film evaporation.

Embodiment

One according to DE 10 2005 010 151 B3 discolored fuel oil obtained from waste oil was evaporated in a VDL 70 thin film evaporator with 4dm ² WRS to 210 ° C at 5.2 mbar. This resulted in a liquid residue of 4.5% and a condensation loss of 1.0%. 94.5% turned out to be a permanently clear Bidestiliat. Increasing the evaporator temperature to 220 degrees C lowered the liquid residue to 1.1 percent and 97.9 percent was a consistently clear distillate distillate

Claims (7)

1. Method for stabilising heating oil or diesel oil recovered by fractional distillation, or pyrolysis oil recovered from rubber or organic substances by first permitting or stimulating a dark discolouration of the diesel oil, heating oil or pyrolysis oil, by conducting an oxidising treatment of the diesel oil, heating oil or pyrolysis oil and then subjecting the darkened diesel oil, heating oil or pyrolysis oil to a distillation step in which the dark discolouration is removed, by carrying out the distillation in a thin-film evaporator, wherein the discoloured diesel oil, heating oil or pyrolysis oil is passed as a thin film over a hot evaporator surface maintained at about 180 to 240 degrees C in a thin-film evaporator under conditions of partial vacuum and the vapour-phase component which forms thereby is condensed as diesel oil or heating oil.
2. Method according to claim 1, characterised in that the heating oil or diesel oil to be stabilised was recovered from a depolymerisation process of residue containing hydrocarbons by fractional distillation of the vapour phase.
3. Method according to claim 1 or 2, characterised in that the darkening process is retarded or stopped during an intermediate storage phase before the distillation of the heating oil or diesel oil to remove the dark colouration by preventing its exposure to light and/or air or by storing it in a barrier gas atmosphere.
4. Method according to any one of claims 1 to 3, characterised in that the oxidising treatment takes place in an oxidising atmosphere, particularly with oxygen, preferably with air.
5. Method according to any one of claims 1 to 4, characterised in that the diesel oil or heating oil is subjected to vigorous mixing, preferably a bubbling process with at least one oxidising fluid.
6. Method according to any one of claims 1 to 5, characterised in that the discoloured diesel oil or heating oil is passed as a thin film over an evaporator surface at a heat of about 200 to 230 degrees C in a thin-film evaporator under conditions of partial vacuum and the vapour-phase component which forms thereby is then condensed as diesel oil or heating oil.
7. Method according to any one of claims 1 to 6, characterised in that the thin film evaporation takes place under an absolute pressure of about 1 to 500 mbar, preferably 2 to 100 mbar.