DE4114434C2 - Process for the production of pumpable mixtures by thermal treatment of synthetic, organic waste with reduced coke formation - Google Patents

Description

The method according to the invention relates to the thermal treatment of synthetic, organic wastes with melting and breaking of chemical bonds in one chose temperature, pressure and residence time range in which no or only a small one Coke formation occurs.

The thermal pretreatment of synthetic, organic wastes has recently been Years in connection with the hydrolytic splitting of such waste achieved.

DE 36 02 041 is the thermal pretreatment of carbon-containing Waste of synthetic origin disclosed. Temperatures of 75-800 ° C, Pressures of 1-600 bar and residence times of 1 minute to 6 hours are required. Also in the absence of mashing oils, viscosities in the liquid product are obtained which correspond to those of products obtained in the presence of mashing oils. Feedstocks are plastics that are first melted.

The thermal pretreatment is also under in the corresponding EP-B-0236 701 Hydrogen or inert gas in a temperature range of 75-600 ° C, a Druckbe range from 1-600 bar and a residence time of 1 minute to 6 hours. Also the addition of protic solvents is disclosed in this patent and the addition of rubbing oils and catalysts.

The procedures disclosed in DE 36 02 041 and in EP-B-0236 701 lead however, to undesirable coke formation, the coke sometimes being coarse and too Blockages and deposits can result in the entire system.  

The applicant has now surprisingly found that when choosing a relatively narrow Temperature and pressure range and use of an insert mixture, which initially on is melted, the formation of coke can be avoided or largely avoided, despite the use of long dwell times. This result is achieved by a method for Manufacture of pumpable mixtures by thermal treatment of the waste characterized in that this without rubbing oil or with up to 50% rubbing oil, based on the Waste mixture to be melted, a temperature of 220-350 ° C and a Pressure from 10 hPa to 0.1 MPa (1 bar) with a residence time of 0.5 to 24 hours the.

It has accordingly been found that, surprisingly, in the case of use mixtures which are added can be melted, using temperatures from 250 to 350 ° C even in the absence of mashing oil, is sufficient to obtain pumpable mixtures, which can be easily fed into the hydrogenation reactor without coke formation or Significant coke formation occurs, with the resulting gases, especially HCl, however also H₂S, HBr and others by applying a slight negative pressure or by on prefer inert carrier gases such as CO₂, N₂, H₂ and others from the reaction zone be removed.

A pressure of 10 hPa to <0.1 MPa (<1 bar) is preferably used. To the invention To achieve the result, mashing oils are not necessary. Mashing oils can be invented However, according to the invention. The addition of an amount of 50 wt. %, preferably of 20 wt .-% based on the amount of waste in the formation of a pumpba Ren porridge have a favorable effect, so that such porridge may already be at temperatures of 270 -340 ° C can be obtained.  

The thermal treatment can also be started by adding certain additives be increased. One or more compounds, for example, can be used as additives from the group: phenols, sulfur compounds, alcohols or amines be added.

In general, longer dwell times are indicated at lower temperatures turns.

The present invention allows waste or waste mixtures for the first time or contaminated waste of organic, synthetic origin without or to convert largely into a pumpable material without coke formation.

Common high-pressure pumps or other high-pressure conveying devices can be used as pumps such as B. extruders are used. It can be particularly high rates may be advantageous, the necessary for the thermal treatment Heat through an extruder with direct heat input or heat through Friction or by a heated screw, such as. B. by a double-barreled  Feed the snail at least partially.

According to the invention, meltable synthetic organic organic compounds are used Waste in question, such as B. Thermoplastics. However, other synthetic, or ganic waste, such as thermosets, elastomers, waste oils, shredder waste, difficult to dispose of organic chemicals, rejects, cable waste, textile waste, etc. At least one component from the group: Crude oil, crude oil components, cycle oil, crude oil products, coal including brown coal, coal components and coal products, oil shale, oil shale components and products from oil shale, oil sand, pyrolysis oils, bitumen, asphalt, asphaltenes, their Components and their products are used. The particular advantage of the present the invention is that when using meltable waste mixtures, the other synthetic, organic waste can be added, pumpable mixtures coke-free can be produced, in the subsequent hydrolytic cleavage Hydrogen, especially in the gasoline and medium oil boiling range can be obtained NEN, the heteroatoms present in the waste as hydrogen compounds, such as B. HCl, H₂S, NH₃, etc., but it must be taken into account that he thermal treatment according to the invention chlorine is largely split off as HCl. During the thermal treatment, stirring or other means is preferred mixes. The splitting thermal treatment can be discontinuous and continuous be performed. An agitator, for example, can be used for continuous operation selkaskade can be used. In the case of a discontinuous driving style, a pre container, the setting of the gap temperature and dwell time are particularly favorable. After reaching a certain viscosity, the temperature can be reduced by approx. 50 ° K the further splitting can be interrupted or slowed down. The stop pen  unwanted post-reactions in further processing containers such as B. in a template before the hydrogenation reactor can be added by adding a radical stopper, such as e.g. B. be achieved by polyphenol.

On the other hand, by adding radical formers with a relatively high decomposition temperature, such as. B. of tert-butyl hydroperoxide, the thermal cleavage be favored, so that similar to the addition of mentioned additives and mashing oils already at lower Temperatures and shorter dwell time the desired thermal fission can be achieved.

The cleavage can also be carried out by adding catalysts be favored. Suitable catalysts are for example wise aluminum oxide and / or bleaching earth with or without Pretreatment such as B. by acids, iron compounds such as ferrocene and / or iron pentacarbonyl and others, the iron compounds preferably only against End of the thermal cleavage are added. The mentioned catalysts can also in the later hydrating cleavage prove to be beneficial. Solid unwanted parts in the waste mixture or those which only formed during the thermal treatment can be in front of or behind it Filtration, centrifugation and other separation processes be separated. It is also possible to grind such fixed proportions so that separation is not required is.

The inventive method is by the following examples explained.

example 1

A mixture of 45% by weight of polyethylene, 30% by weight  Polypropylene and 25 wt% polystyrene became one thermal treatment at 300 ° C for 5 hours subject. The viscosity of the starting mixture was not measurable at 200 ° C, but was after thermal treatment 1200 mPas. The mixture was with a conventional pump. Coke formation was not detectable.

Example 2

A mixture of 50 wt .-% polyethylene, 30 wt .-% poly propylene, 10% by weight polystyrene and 10% by weight poly urethane was subjected to a thermal treatment at 300 ° C subjected for 5 hours. The mixture liquefied itself, only the polyurethane content remained largely as obtained highly viscous second phase.

The same mixture was added with the addition of 0.5% by weight. tert-Butyl hydroperoxide thermal at 360 ° C for 2 hours treated. Then a homogeneous liquid resulted without separate polyurethane phase with a viscosity of 1000 mPas at 200 ° C, which was easy to pump. Due to the high temperature during the second treatment there was noticeable coke formation.

The second treatment was repeated at 280 ° C and a residence time of 5 hours. It became homogeneous Receive liquid with a viscosity of 1200 mPas at 200 ° C. There was no coke formation.

Example 3

A mixture of 40 wt .-% polyethylene, 30 wt .-% poly propylene, 10% by weight polystyrene, 10% by weight polyurethane and 10 wt% polyvinyl chloride was at 260 ° C during  Thermally treated for 8 hours.

The viscosity after the treatment was 1300 mPas at 200 ° C. A small amount of coke was added to the mixture particles found. By stirring during the thermal Treatment allowed the grain size of the coke to be smaller Can be reduced by 10 µ.

The thermal treatment was carried out at normal pressure. During the thermal treatment, chlorine was used as HCl released. The residual dissolved chlorine content was after treatment 300 ppm.

The same attempt was made using a Repeated vacuum of 50 mbar. The remaining salary Chlorine was now 20 ppm. Coke formation could not can be determined more.

Also by adding 10% by weight vacuum gas oil the amount of coke formed in experiment 3 by reducing set the treatment temperature to 230 ° C significantly can be reduced.

Example 4

Example 3 was repeated, but with stirring at 50 mbar simultaneously nitrogen through the mixture headed. The residual chlorine content was after Treatment 2 ppm. The coke formed remained due its small grain size is less than 10 µ in suspension. The pumpability of the mixture was increased by the coke content not significantly affected.

The mixture obtained is due to its low Residual HCl content in standard high pressure equipment processable so that no chlorine-resistant, expensive steels must be used.  

Example 5

A plastic mixture of household waste was added for 7 hours Treated 270 ° C. During treatment was normal pressure nitrogen passed through the mixture. The treated product had a viscosity of 1400 mPas at 200 ° C and a residual chlorine content of 30 ppm. The mixture contained coke particles.

The experiment was repeated, but 15% by weight of crude oil residue and 0.5 wt .-% stearylamine added. The amount of coke formed was significantly less.

Claims (4)

1. A process for the preparation of pumpable mixtures by thermal treatment of synthetic, organic waste, characterized in that the waste, without rubbing oil or with up to 50% grinding oil, based on the waste mixture, is melted and a temperature of 220-350 ° C. and subjected to a pressure of 10 hPa to 0.1 MPa with a residence time of 0.5 to 24 hours. 2. The method according to claim 1, characterized in that the thermal loading the resulting gases by applying a vacuum and / or introducing inert gas are removed from the reaction mixture. 3. Process according to claims 1 and 2, characterized in that radical formers are added, preferably those with a relatively high decomposition temperature. 4. Process according to claims 1-3, characterized in that tert-butyl hy droperoxide is used.