FR2811247A1 - Liquid fuel production comprises recovery of plastic from cable insulation in computers or household appliances, and dissolving plastic in solvent mixed with oil using dynamic autoclave - Google Patents

Abstract

Plastic is recovered from waste electronic equipment and turned into a liquid fuel. The equipment is dissolved in a solvent mixed with oil using a dynamic autoclave. Preferred Features: The oil may be waste motor oil. After the plastic has been dissolved, the solvent is recycled by absorption into a gas and then desorption. The absorption and desorption both take place in the autoclave. The removal of the solvent makes the plastic form an emulsion in the oil.

Description

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DESCRIPTION

  The present invention relates to, as a new industrial product, a method of stripping used electrical cable, the

  sheath is PVC, for recycling.

  Polymer solutions are already known which cover in their industries a very broad spectrum of use, and this because they often constitute a necessary step during synthesis, purification such as fractionation, or precipitation but also because they have macroscopic properties

  1 o originals used in many fields of applications.

  The description of such systems is based on two essential themes

  either: Solubility and conformation, which are intimately linked to the concept of sequence. 1 5 Indeed, the connection between adjacent elements constituting the macromolecular chain will cause a reduction in the degree of freedom of these elements and induce the existence of interactions at more or less long distance which will give polymer solutions very different properties. particular facts, compared to those of small

2o molecules.

  The process of mechanically stripping electrical cables is also known, a process which involves grinding or shredding followed by separation on a densimetric table of the metal fraction and

of the PVC fraction.

  This process has the following disadvantages: Grinding or shredding are expensive operations due to their high energy consumption on the one hand and the wear of the

hardware on the other hand.

  In addition, crushing and shredding have the undesirable effect of encrusting metallic particles in the PVC decortica, and, in multi-stranded conductive cables, the pollution rate can amount to more than ten% by weight, d 'o an equivalent loss of metal. The densimetric table does not ensure an absolute separation of the two fractions, namely metal and PVC, at least if we

  wishes to work at acceptable rates.

  And in fine particles the presence of PVC in the metal can reach almost three% by weight, at least if we want

  sufficiently economical passage speeds.

  The presence of PVC in the metal being harmful for melting downstream of said metal, since it generates carbonates and chlorides which must be got rid of by different operations, each of which has

43 its cost.

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  On the other hand, the metal obtained by mechanical shelling is in the form of fragmented particles and it is always difficult, especially in small particles to realize

  quickly the degree of purity of a considered fragmentation.

  This difficulty of rapid examination, of a lot of metal, generates innumerable disputes between customers and suppliers, one claiming

  that his product is impeccable, the other claiming the opposite.

  Finally the husk released by this method is a product which poses many environmental problems and therefore it must be put in

  1 o discharge which entails a cost.

  The present invention aims to remedy these drawbacks and relates to a chemical process for the stripping of the used electric cable with PVC sheath, which operates by dissolving said PVC in a solvent, then in restoring said PVC by absorption of said solvent in a gas followed by desorption of said solvent in a

  condenser, said solvent then being reused in the process.

  The present process has many advantages over the conventional mechanical method used universally today as well: - it is low in energy consumption - it restores a clean metal free of any pollution - it restores an unmilled whole metal easy to control designed to ensure its quality - it avoids the landfill of PVC with the costs that this entails - it increases profitability due to the possible commercialization of the PVC obtained - it is part of the improvement of industrial processes by with a view to reducing their effects on the environment

  3o The invention will be better understood by referring to the description below.

  below as well as the accompanying drawings, of which: FIG. 1) is a view of the first phase of the cycle of the present

  process, ie the dissolution of PVC sheaths.

  Figure 2) is a view of the second phase of the present cycle

  process, ie refining the PVC solution.

  Figure 3) is a view of the third phase of the present cycle

  process, ie the separation of the solvent and the PVC.

  Figure 4) is an overview of the installation according to the present method. Thus in (1) a truck loaded with used electrical cables (2) dumps its load into a drum (3) through an opening (4) provided with an access door (5), said drum being an isolated autoclave

and thermally regulated.

  Said drum ends with a shaft mounted on a geared motor (6) in said shaft is provided a cavity in which are

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  arranged four pipes leading to a rotary junction (7), said

  pipes extending beyond said rotary junction.

  Each of these pipes fulfills its own function, thus the pipe (8) is used to introduce the solvent or the solution into the drum (3), the pipe (9) is used to extract them. The pipe (10) brings the gas into the drum and the pipe (11) is used to

extract it.

  A pump (12) is used to pump said gas and another pump (13) is used

  pumping said solution and said solvent.

  In (14) is shown a gas tank in the gaseous state, and in (15) a tank for the same gas but in the liquid state. In (16) is

shown a gas pressure regulator.

  In (17) is shown a tank containing fresh solvent and in

  (18) a tank containing concentrated PVC solvent.

  In (19) are shown a series of valves.

  In (20) is represented the entry of the liquid gas.

  From (21) to (28) are shown intermediate boiler tanks containing a solution increasingly loaded with PVC, the tank (21) contains a new solvent and the tank (28) a very

  concentrated close to saturation.

  In (29) is shown a pipe which brings the concentrated solution of PVC contained in the tank (18) into a centrifugal decanter (30). Said decanter has three outlets, one of which is an underflow (31) of the decanter, the other is an overflow (32) of said decanter while the third is a median outlet (33) of said decanter, the latter is directed towards a filter press (34) which in turn has two outlets and one of which (35) is a drain outlet and the other (36) comes out to bring the solution to a mixer (37). driven by an electric motor (39), said mixer has two inputs, one of which (40) is a manual input and the other (41) of which is connected to three

  ingredient tanks (42), (43), (44).

  In (45) is shown a pipe which goes towards the soaking tank of a coating machine in which a bubbling cylinder (47) soaks which moistens a transmitting cylinder (48) which in turn moistens a calender (49) whose surface is smooth or

grained as desired.

  A stripper cylinder (50) is placed against said grille at a

  certain distance from said transmitting cylinder.

  A sealed tunnel (51) extends the coating, the PVC film (52) which leaves said tunnel passes over a deflection cylinder (53), then it is

43 wound by a winder (54).

  -4 - Said coating and said tunnel are placed in a hermetically sealed enclosure (55) in which a gas flows against the current

hot from the pipe (56).

  The hot gas comes from an air heater (57) which is provided with a precise thermal regulator. Said gas enters said tunnel through an opening (58) and exits through another opening (59), the outlet of the hot gases (59) is directed towards a condenser (60) cooled by the ambient air. Said condenser has an outlet connected to a pipe which is directed towards 1 o a decanter (61) the latter in turn has two outlets one of which (62) is connected to a pipe which is directed towards the tank (17) of solvent (9) for the process and the other of which is directed to an air heater

  (57) whose exit is directed towards the entrance of the tunnel (51).

  On the drum door (3) there is also a valve

1 5 discharge (63).

  The installation according to the present method also comprises a programmable automaton which, via sensors and relay

  power governs the entire control system of said installation.

  In addition, all the tanks and reservoirs of the present process

  containing liquids are boilers.

  The installation according to the present process operates as follows: The operation is cyclic and a cycle comprises several

  time, this is valid for the first phase of the process.

  First the drum (3) is brought into position

  vertical and its access door (5) is open.

  A dump truck dumps a quantity of electric cables into it

  used then said access door is closed.

  At this stage, the reservoirs (21) to (28) are filled with PVC solutions, the least concentrated of which is located on the left most (21) and the most concentrated of which is located on the most right (18), this distribution being

  the fact of the previous cycles of the process.

  At the second stage of the cycle, the air present in the drum (3) is swept, and for this purpose compressed gas supplied by the pipe (10) is injected there. The valve (5) allows the evacuation of said air. At the third stage of the cycle and when the air present in said

  drum has been completely evacuated by tilting (64) said drum.

  At the fourth stage of the cycle, the PVC solvent contained in the reservoir (28) is introduced into said drum, this is the most

  more concentrated in PVC of all the tanks (21) to (28).

  This introduction is ensured by the pump (13).

  At the fifth cycle time the drum (3) is rotated and it

  no longer stops until the end of the cycle.

  The bubbling of said used cable into said solution results in a dissolution of part of the PVC sheaths thereof, and this has the effect of further increasing the concentration of said solution. After a certain mixing time, said solution is so concentrated that its solubilizing action is almost entirely stopped. At the sixth stage of the cycle, the drum is emptied of its liquid fraction, either of said concentrated solvent and the latter is then directed by gravity into the tank (18) or that which contains the

  the busiest solution for this first process phase.

  1 0 At the start of the seventh time of the cycle, the drum is empty of liquid, and the reservoir (28) also. Then injected into said drum the

  contents of the reservoir (27), and the bubbling of the cable resumes.

  After a certain time the liquid content of said drum is drained

in the tank (28).

  The following times are repeated in the same way, each time emptying the drum into a tank emptied at the previous time and introducing more and more solution into said drum.

  poorer, from reservoirs upstream.

  At the last time of the cycle, the filling is done with solvent

  new from the tank (17).

  The cable in the drum is then completely free of its PVC sheath, and it no longer has any traces

  of said PVC, its appearance being impeccable.

  At the last time of the cycle and after the last emptying of said drum, the latter stops rotating then it pivots to find itself

  in an upright position, its access door located downwards.

  Said door then opens and the bare metal cable which is located

  into the drum pours onto a truck (38) laced under it.

  Once the cycle is complete, the truck then heads for the foundry.

  3o In parallel with the cycle described above, operations of a continuous nature take place which do not depend chronologically

of said cycle.

  Thus, the first phase of these operations consists in refining the PVC solution obtained with a view to its use for manufacturing

finished or semi-finished products.

  The purpose of this refining is to remove all the impurities which could have mixed with said solution, then to readjust the latter, as to its color, as well as to the content of its various constituents such as

  talc, plasticizers, stabilizers.

  This refining comprises several stages, the first of which is intended to remove from the solution all the particles which are heavier, or

  those that are lighter than said solution.

  This is done in a centrifugal decanter (30), so the solution arrives in the decanter through the pipe (29) and the centrifugation extracts the heavy particles by an underflow (31) which go to the drain, and

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  it also extracts light particles through the outlet (32) which

also go to the drain.

  At the outlet (35) of the decanter, the solution is perfectly pure, but to ensure total safety, this solution is directed to a filter press which still extracts any particles which

  could have escaped the decanter.

  Once purified of its impurities, the solution is adjusted and rectified

  regarding some of its parameters.

  This second operation is done by a mixer. It is a mixer into which we cyclically introduce a

  quantity of said solution, then of the required ingredients.

  The ingredients in question are stored in tanks (42) (43) (44), connected to the counter by a pipe (41) and by

through valves (19).

  A manual input (40) is provided on said mixer for

ad hoc adjustments.

  Finally, a last operation of the present process consists in separating

  solvent for PVC while transforming PVC into a film.

  This operation is done on a coating machine, on the radiator grille of

  which is deposited a liquid film of the solution.

  The solvent of this film being absorbed in a gas, which has the effect of transforming said liquid film into a solid PVC film free of solvent. The operation proceeds as follows: The solution is directed to a container (46) of the coating machine, this container

  has a thermal regulation and a level regulator.

  A bubbler cylinder (47) takes a quantity of solution from said tank. This is deposited by a transmitting cylinder (48) on an absorption grille (49), which also has a regulation

thermal.

  This coating machine is placed under a bell and a strong current of hot gas sweeps through its enclosure so that the solvent present

  in said enclosure is absorbed by said gas.

  On said calender (49) a film is then formed, which is peeled off by the stripper cylinder (50), then said film passes through a tunnel (51) to restore all of the solvent that it still contains, and finally it leaves the tunnel and is returned to a winder (54) via

a return cylinder (53).

  The coil thus obtained is ready to be marketed.

  4o The hot gas in which the solvent has been absorbed is pumped towards the condenser (60) where it is cooled thus causing the desorption of the solvent which it contains, the latter is then collected in a settling tank (61), then it returns by gravity to the new solvent stock (17) and it is thus thus recycled indefinitely, at

Except for process losses.

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  The solvent according to the present process works in a closed cycle, and therefore it is never in contact with the atmosphere, and therefore does not

  causes no odor in the ambient air.

  As for the gas, at the outlet of the condenser, stripped of its solvent then returns to the enclosure of the coating machine, after having been heated by the air heater (57), and a circuit is thus

definitely ensured by this gas.

  The various fluids which circulate in the installation according to the present process are, the service of the drum in solvent and solution, they are

  1 o provided by the piping (7) and (8).

  Gas circulation in the absorption and desorption system

  is provided by the piping (56) and (63).

  The gas circulation of the drum (3) is ensured by the piping (10) and (11), connected to the piping (56) and (63) and it thus benefits from the desorption of the condenser (60) which allows evacuate any trace of solvent in said drum after the last time of each cycle, that is to say before the door of said drum is opened for unloading. The return of the desorbed solvent to the tank of new solvent is

provided by the piping (62).

  The parameters of this process are as follows: - the raw material to be treated is used electrical cable, the insulation sheath of which is made of PVC, and the conductors of CU and

in AL or both.

  - the objectives are the separation of PVC and metals with a respectively high degree, and the transformation of said PVC into a thin film of adjustable thickness between 50 to 300 microns, directly marketable, and finally the restitution of a

  unaltered and unfractionated metal.

  3c - the chemical formula of the chemical solvent is

(C6H120) 92% + (H20) 8%

  - the boiling point of this solvent is 128 C - the absorption temperature in the gas of said solvent is 115 C - the desorption temperature of said solvent of said gas is lower than 25 C - the setting temperature solution of said PVC in said solvent is 95 C the pumping and storage temperature of said solution is 90 C the absorption and desorption gas is: N2, it is also used for inerting the interior volumes of the process - the PVC of electrical cables is classic PVC, of formula

H2C = CHCI

  - the maximum temperature of PVC is limited to 95 C.

  - the overpressure of N2 in the installation is 150g / cm2

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  - the color to be obtained from the PVC is a dark gray - the adjustment of the color of the PVC in the counter is made using white pigments and black pigments - the duration of the time for dissolving the PVC in the solvent is 6 hours for the first time and 15 minutes for the last time - the number of successive solutions in a cycle is - the duration of a complete cycle is recommended over a period of 24

1 o hours.

  Thus, the dissolution of PVC can be done by other solvent than those mentioned having

  other affinities with other polymers making up the sheaths of electric cables.

  Electric cables can be mixed with other products with

polymers to dissolve.

  Said other products may be used computers or devices

  appliances or electronics.

  The solvents can be added or replaced by other liquids having for

  property of suspending and / or melting said polymers.

  Said other liquids can be oils.

  Said oils can be vegetable oils or motor vehicle drain oils. Said operating parameters of said process may be different than those

  described and be adapted to the nature of said other products.

  The installation shell can be replaced by a crystallization or polymerization tower and can produce granules or polymer sand or a viscous material. The desorption of the liquid can only be partial in the case of a liquid composed of a solvent, an oil and polymers, the solvent can be the object of a desorption and the oil

  remain in the liquid state mixed with said polymer.

  Said oil in a liquid state and said polymer can be returned hot, the polymer

  being suspended in said oil to form an emulsion.

  Said emulsion constitutes a liquid fuel.

  The present process can be attached to a thermal power plant and provide the latter

said liquid fuel.

  Said liquid fuel from the present process has combustion properties

  36 appropriate, what would not have said polymers if they were incinerated as.

  In the present process it is easy to understand that the metal CU and AL obtained is of excellent chemical quality, since no agent

  aggressive only came to alter their condition.

  This, however, insofar as the required parameters have been respected. For PVC, its passage to the dissolved state can give rise to

  questions about its final quality.

  However, given the current knowledge in terms of dissolution of polymers, and especially considering the original mode of dissolution implemented in this process, it appears that the PVC thus recycled not only has the characteristics of the original PVC in many respects, but even exceeds the latter, in some of its performances. This is explained by the fact that the PVC compount, due to its dissolution undergoes a homogenization operation, in fact the different elements which compose it are more intimately in

  presence of each other for the duration of the dissolved state.

  The extraction of said PVC by absorption in a gas makes it possible to carry out the separation and recycling of said solvent at relatively low temperatures 2o, and in all cases below its boiling point. Therefore, the solvent does not undergo degradation due to the passage to a possible vapor phase, and its recycling can be envisaged

  thus to infinity, minus the minimum losses of the process.

  This description is not exhaustive and constitutes only a

  example to which many modifications can be

  27 made, without departing from its scope.

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Claims (4)

claims   1) Process for the treatment of used computers and household or electronic appliance, comprising physicochemical means which ensure the separation of plastics as well as their transformation into a liquid fuel characterized in that: Said computers or household or electronic appliances are put in solution in a solvent mixed with oil, and in that said mixing takes place in a dynamic autoclave (3) 2) Method according to claim 1) characterized in that said oil is automotive drain oil 3) Method according to claim 1) characterized in that said mixture is then treated to restore said solvent 4) Method according to claim 3) characterized in that said treatment consists of absorption of the solvent in a gas followed by desorption) Method according to claim 4) characterized in that said absorption takes place in a dynamic autoclave 6) Method according to claim 4) characterized in that said desorption in a dynamic autoclave causes said plastic to be suspended in said oil to form an emulsion 7) Method according to claim 6) characterized in that said emulsion is used 22 as liquid fuel