The invention concerns a process and the equipment for the preparation of waste containing plastic and organic liquids based on mineral oil, edible oil, fat and similar.
In view of the increasing cost of crude oil and the ever restricting obligations attached to the processing of waste material and the recycling of scrap, there is considerable interest in the processing of plastic scrap which, for example, might be separated from residual waste.
From WO 2005/071043 A1 a procedure is known whereby plastic scrap is processed into oil.
In this procedure the separated plastic scrap is hermetically sealed, compacted and delivered to a melt container. Then follows a separation into a first liquid phase, a first gas phase and residue. The liquid phase and the first gas phase are delivered to a vaporiser in which a second liquid phase and a second gas phase separation takes place. The second liquid phase is warmed further in a secondary heater. The third gas phase and the second gas phase are delivered from the vaporising container to a cracking tower in which long chain hydrocarbons are cracked. The resulting gas is then condensed into light liquid in a condenser.
This complex process with a melt container, several vaporising or secondary heating containers, a separate crack installation and a condenser calls for a considerable investment in processing equipment.
In view of this the object of the invention is to produce a process and the equipment with which to treat waste containing plastic with minimal investment in equipment.
According to the invention the melting, vaporising, and cracking should be arranged in a single reactor in which the melting and cracking zone are split or are in two downstream switched reactors such that the equipment costs described at the beginning are significantly reduced.
The gas phase after the crack zone will for example be taken to a distillation column that would operate such that short chain polymers condense and are then returned to the reactor crack zone. After the distillation column and the associated coolers those relatively short chained gaseous hydrocarbons can be used as fuel for energy.
The process under the invention can be carried out particularly effectively if the temperatures in the melt zone are as low as possible—approximately from 250° C. to 350° C. max—and in the crack zone approximately from 420° C. up to 450° C.
Any impurities in the reactor including non-molten plastics drop into the melting zone and into the crack zone and can be removed.
These high calorie residues can be emulsified and also used as fuel for energy.
After condensing while still in light liquid any impurities can be removed during processing for example by absorption.
The reactor with the melting zone and/or the crack zone must be fitted with a device to ensure that the melt from the entering material is continuously monitored. This supply device can, for example, be a screw feeder attached to one of the zones.
According to a preferred embodiment of the invention the material mixture, which is to be processed, can be fed to the reactor in at least two symmetrical points of entry.
It is particularly advantageous that this material be compacted prior to being loaded into the reactor.
The reactor is preferably laid out as a horizontal container.
As an example a part of the liquid product after cooling and quenching can be taken as a coolant fluid through a cooler and used as a quenching fluid for cooling and condensing gases.
The heating for melting in the melting and crack zones is preferably by means of pipes within the reactor which practically form a heat exchanger. The number of pipes, or more exactly, their heating surfaces being appropriate for the heating level required.
As mentioned before a single reactor can be supplied with a melting zone and crack zone. As an alternative two reactors can be supplied switched downstream. For the heating of the suspension heating pipes are provided within the reactor. In one version of the invention the heat input and the distribution of the heat originate from the individual pipes at the front at one end of the reactor. The output distributor and the heat output are located at the opposite side of the reactor. As mentioned the pipes provide circulation with their associated distributors and coil for removing the scaling on the internal cladding of the reactor concerned.
The single reactor with melting zone and crack zone or the two-switched downstream reactors have a heat exchanger in which the suspension or molten mass is warmed.
In one preferred embodiment these heat exchangers are provided as pipe heat exchangers in which one pipe having suspension/molten mass has an inner pipe formed into a coil which runs with the suspension and considerably improves the heat transfer with the result that the heat exchanger can be made shorter than those normally available.
In another variant it is preferable if this winding or coil abuts the cladding of the inner pipe so that any residues may be removed.
Since the suspension still contains a certain amount of solid matter, the pump and supply power units are subject to abrasive wear. To minimize this wear a version can be used with an electromagnetic clutch motor such that no part of the clutch unit is in contact with the suspension.
Pump wear can be reduced when the pump is operated magnetically with the drive solenoid located outside the area of the suspension. Preferably a double action piston pump with two cylinders should be used separated from the piston and operated via the solenoid drive.
This solenoid drive can have an external magnet covering the pump cylinder that is controlled by a linear actuator so that the stroke of the piston is in line with the linear actuator.
A difference between the processes mentioned and the new process as in
1) Continuous feeding 20/22 of plastic materials and organic liquids based on mineral oil or edible oil and fat.
2) Melting the supplied material mixtures within the temperature range 250° C. and 350° C. to a liquid mass similar to stirred emulsion paint 10.3 in the area of the melting chamber 1.1.
3) Contaminants like sand and other non-organic substances like plastic materials that do not melt at 350° C. or non-organic paints 5 fall out and are delivered through the coil into the chute 6.1 to the special waste container that as a removable container will be disposed of in a special incinerator.
4) Via the separating wall and the skimming wall 10.1 and 10.2 the molten masses released from the foreign matter 10.3 pass into the crack zone 1.2 in which with temperatures between 420° C. and 450° C. the long chained polymers are held at temperature until they are delivered as short chain hydrocarbons to the distillation column in the form of gas 10.5 and mixed with the gases 11 from the melting stage 1.1.
5) The distillation tower 23 is in this respect so designed that long chain hydrocarbons condense as C24 and return to the crack reactor 1.2 and remain there until they are shorter than C24. The bandwidth at cracking lies between C1 and C22 with the majority between C12 and C16 (predominantly methane) up to C4 (predominantly propane) remain at the specified temperature in the distillation tower 23 in the form of gas 32.4 for salt heating.
6) Of high energy but not in the form of gas tar and bitumen type substances such as the hydrocarbon excess arising from cracking polymers sink in reactor part 1.2 and are delivered via the chute 8 and by the removal device 8.1 into a container 31.9. This residue 7 can be emulsified with the water 27.7 from the product and water separation container and with the product similar to heating oil 27.1 in tank 31.9 by means of ultra sound 31.8 and disposed of as fuel for the salt heating in the multi-fuel stove 32.4 as high calorie liquid fuel 31.9 or optionally used in a liquid fuel stove.
Since substrates similar to heating oils condensed contaminants, sulphur traces, particularly sulphuric acids, halogen acids e.g. hydrochloric acids (HC2) and possibly disturbing organic acids are present it is suggested to install equipment as indicated in FIGS. 7,8 and 9 absorption units to remove the above mentioned elements. In this connection basic reacting molecular sieves are suitable in the form of silica gel filter, which can be re-used after re-generation. After these elements have been removed the light liquid meets the quality requirements of low sulphur heating oil.
On account of the high ambient temperatures the magnets are made from a special cobalt alloy.
Through an external linear drive 35.3 the piston moves in the direction 35.3 of the magnetic force. No plastic material can pass through the free moving valve flap 35.6 which is not completely melted
The effectiveness of pump activity and energy consumed corresponds with an open non-clogging pump in wastewater applications.
The main crack process takes place in the dynamic part of the heat exchanger 9.5 at 420 to 450° C. This heat exchanger 9.5 has 3 parallel-switched streaming routes in which there is a rinsing coil 9.6. In the waiting zone 38 the uncracked long chain hydrocarbons 8 separate.
The molten suspension then passes through an overflow to the crack reactor 10 in which the long chain hydrocarbons are cracked at 420 to 450° C. The construction of this crack reactor can be taken from
The gas arising from the cracking is condensed in a condenser 10.2 and passes to a Venturi cooler 11 and to a connected pipe bundle cooler 11.1 in which the condensate is cooled. This condensate/vapour mixture cooled down to 30° C. then passes to an intermediate container 15. The high calorie gas can be used for a steam generator 19 or the liquid salt heater 20. The residue taken from the intermediate container 15 can undergo several rinsing stages 22.1, 22.2, 22.3 in which under the process from
In the crack reactor 10 any remaining long chain hydrocarbons are removed and delivered to an emulsifying container 16 e.g. using ultra-sound and then used for energy in the units 19, 20 (steam generator, liquid salt heater) so that this energy is used for heating the suspension in the melting reactor 8 and in the crack reactor 10. These processes are conducted preferably in an atmosphere of nitrogen under which the nitrogen arises for example from an air separation 25.
FIGS. 15/15.1/15.2 and 16 show another variation whereby molten plastic scrap in a melt pipe 9.5 and the melt using the supply coils (9.6) which is circulated and heated by a heating medium (9) is pumped in directly by the supply screw pump (39).
The plastic scrap (20) passes into the hopper (21.1) of the feed screw. The feed screw (21.1) feeds the plastic materials to the compactor (22.2). Here the material is compacted and the air withdrawn using nitrogen.
The compactor (22.2) feeds the material into the melt reactor (9.5). The loading of the melt reactor can be stopped using valves (18).
The compacted material is pressed into the melted plastic (10.3) by means of the feed coils (9.6) and this way the liquefying of the plastic material is accelerated as a result of the dissolving effect of the already pre-heated material.
In the first zone of the melt reactor the material is heated to 120° C. max. Any dampness contained in the material (water) will condense and the light elusive components like plasticisers will dissolve and be removed via the bell (9.10) via the contact (11).
Based on the special arrangement of the exchanger (9.5/9.6) heated by liquid salt (9) with a dynamic heat transfer under vortexing (9.10) and the scratching off of contaminants (7) heat transfer happens with a very low Delta-T. In this way a depolymerisation is largely prevented during the liquefying process.
In the following zone the material is further heated until melting takes place. The melt is then transferred by the screw pump (39) into the crack reactor (9.5).
A larger pipe from the crack reactor is fitted with a closed coil that delivers the melt to the sump (10.4) below. It is then further heated up to boiling point. In the other pipes (9.6) from the reactor (9.5) the melt is brought up from the sump (9.7/9.10) and also heated to not less than boiling point.
The melt is thus constantly circulated and then delivered by the outer pumps (9.6) to the upper pot (10.4) of the crack reactor from where using a closed coil (39) it is delivered down below by the middle pipe and then mixed with new melt (10.3) from the melt reactor (9.6/9.7).
Owing to the enormous heat energy input vapour arises on the pipe wall in the outer pipes which rises to the top and increased by the rotating movement of the screws which gives rise to strong vortexes (9.1) contributing to the degassing of the melt and the triggering of the crack process.
The carbon deposits (7) on the pipe walls are rubbed off by the screws (9.6). These deposits together with the unmelted material at the specified temperature are dumped below using valves (18) into a clinker container if required.
A part of the rising vapour (10.6/23) will condense (10.6) in the distillation column mounted directly over the crack reactor and flow back to the crack reactor. The following partial condenser (40) will receive only vapours that do not condense at the specified temperature. This fraction will be cooled later with product (27.1.1) in a steel rinsing pipe (50.1) and condensed. For the separation of the vapour/liquid phase a Zyklon is used.
The liquid product quantity (27.1.1) required for the steel pipe cooler (50.1) is provided by the pump (27.8). This pump sucks the product from the provisional container (27) and feeds it through the heat exchanger (24.6) such that it is cooled to a temperature of 20 to 90° C. before going on to the steel rinsing pipe (50.1).
From this closed product circulation system there is a partial current that takes off any excess to the product container (60).
For the cooling of the compacting screw (27.1.1) and the product via the heat exchanger (24.6) a cooling unit is used. A regulating unit (40.5) is used for this in order to set the temperature in the partial condenser (40).
The vapour (10.6) originating in the crack reactor consists of short and long chain hydrocarbon molecules and rises in the rectification column (40) upwards. By means of contra-flow (rectification) whereby the vapour (10.5) rises and the liquid mixture (10.6) flows downwards an initial thermal fine separation takes place. A column (23.2) is set up with a suitable packing. The column (23.3) and the following partial condenser (40) are arranged for the relevant crucial separation of hydrocarbons C10 up to C24 carbon atoms per molecule. The pre-fractioned vapour that leaves the column flows through a special distributor in the partial condenser (40.1) through which the condensate from the partial condenser is spread on to the column packing.
In the partial condenser an exact temperature is set using cooling pipes. This temperature can be between 150° C. and 300° C. As a heat carrier (cooling medium) thermo-oil (40.2 and 40.3) is used. The regulating set (40.4) functions as a cold and hot battery that maintains the exact temperature for the thermo-oil.
The unique selling point here is that the temperature flexibility in the partial condenser allows the exact setting of the chain length of the gases leaving the crack reactor. If, for example, the partial condenser (40) is run at approx. 300° C. in a following cooler (50) at more than 95% only those molecules are condensed which consist of a chain length of between approx. 10 C to approx. 24 C atoms with the main focus on C12 to C16. This means that the gases leaving the partial condenser at a temperature of approx. 300° C. will in the partial condenser be only those having molecules up to a maximum chain length of C24. Should the temperature be raised/lowered the molecular chain length will be correspondingly increased/decreased.
Equally the setting of the temperature in the cooler following the partial condenser is decisive in producing fuel of a particular type. For example should the temperature in the cooler be 70° C. instead of 30° C. the hydrocarbons C1 to C9 would remain in the form of gas whilst longer chain hydrocarbons condense. The so-called light boilers remaining from the gas phase can be removed and used as process energy. By this separation of the light boilers C1-C9 pure diesel fuel can be made direct.
It must be emphasised that not only the packing (23.5) used but also the distributor between the column and the partial condenser are vulnerable to carbon deposits in case the crack process should be continued here.
The vapour from the partial condenser (10.5.1) is fed into a quencher (50.1) by nozzle where this is condensed with product (27.1.1) into diesel. The nozzle can be filled with diesel at a temperature between 20° C. and 90° C. The two-phase mix from the quencher is separated later in a Zyklon (50). The vapours or gases that leave the Zyklon can be used as combustion gas. The separated liquid (diesel) passes to a water collector (phase collector) (60) whence it flows to a storage tank (27.10).
In order to guarantee a constant supply from the quencher nozzle the product flows firstly into a float container (27) the so-called provisional container for the quencher. A pump (27.8) feeds the product from here via a heat exchanger (24.6) to the quencher nozzle. By means of the heat exchanger (24.6) the required temperature for the quencher can be set. An industrial cooler (25) supplies the necessary cooling water.
Using a level control in the float container (27) and a flow regulator any excess product will be drawn off to a phase separator (60).
The applicant undertakes to consider independent claims on the construction of the single reactor (integral reactor having melting and crack zones, melt reactor 8, crack reactor 10, the relative heat exchangers, pumps and drive units, also the medium used and the stages of the process as laid down in the process scheme in
Number | Date | Country | Kind |
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10 2006 039 824.6 | Aug 2006 | DE | national |
10 2006 046 682.9 | Sep 2006 | DE | national |
10 2006 055 388.8 | Nov 2006 | DE | national |
10 2007 039 887.7 | Aug 2007 | DE | national |
This application is a National Stage completion of PCT/EP2007/007419 filed Aug. 23, 2007, which claims priority from German patent application serial nos. 10 2006 039 824.6 filed Aug. 25, 2006; 10 2006 046 682.9 filed Sep. 29, 2006; 10 2006 055 388.8 filed Nov. 22, 2006; and 102007039887.7 filed Aug. 23, 2007.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP07/07419 | 8/23/2007 | WO | 00 | 8/10/2009 |