The object of the invention is a pyrolysis apparatus according to the preamble to claim 1 for processing shredded waste material, such as plastic and/or rubber waste. In the pyrolysis apparatus, a feed device feeds the material into the pyrolysis reactor for pyrolysis treatment. Known pyrolysis apparatuses have been presented in the publications US- 4983278 A, WO-2013095163 A1 , GB-2502126 A, WO-9909948 A1 and WO-9320396 A1.

Pyrolysis, i.e. dry distillation, is a chemical reaction wherein organic solids are

decomposed by heating without allowing oxygen to influence the process. Pyrolysis usually uses either a vacuum, as is the case in vacuum pyrolysis, or an inert atmosphere, such as nitrogen, to supplant atmospheric oxygen. As a general rule, industrial pyrolysis reactions take place at temperatures of 300 to 700 °C. In the pyrolysis apparatus, waste that contains hydrocarbons, for example plastic and/or rubber waste, is processed such that the process mainly produces oil, carbon and gas. According to a known method, plastic and/or rubber waste is shredded and the shredded material is placed in a pyrolysis chamber. The chamber is locked to make it air-tight with an air trap which is usually also the rotary feeder for the material to be processed.

Distributing the heat more evenly leads to complicated cylindrical solutions, in which the pyrolyser chamber atee has to be continuously rotated, which, in turn This leads to difficult sealing problems. In cylindrical pyrolysis chambers, the transfer of heat into the material to be processed also does not occur in the best possible manner, because the material to be processed is in the cylinder at its bottom and touches the surface of the hot cylinder only in a small area. Since the material to be processed is insulating material and thus conducts heat poorly, the conduction of heat from the cylinder casing into the material located at the bottom of the cylinder is not efficient. The situation is similar regardless of whether there is a screw conveyor or a scraper conveyor in the cylindrical or tubular pyrolysis chamber. Known pyrolysis apparatuses have been presented in the publications WO2016082755 A2, US2012111716 A1 and US4983278 A.

The purpose of this invention is to achieve a pyrolysis apparatus that does not have the drawbacks of known apparatuses. The purpose of the invention is to achieve a pyrolysis apparatus, in whose pyrolysis chamber the conduction of heat into the material to be processed is as efficient as possible. The pyrolysis apparatus according to the invention is characterized in what has been presented in the characterising section of claim 1. The pyrolysis apparatus according to the invention is continuous. The pyrolysis apparatus includes any type of feed device, such as a scraper conveyor or a screw conveyor placed in an inclined position, whose bottom part is placed in a liquid, such as oil, contained in a liquid basin. Thereby the liquid forms an air trap to prevent air from entering into the reactor. The material to be fed into the pyrolysis apparatus is conveyed into a bin which simultaneously forms a liquid basin. The scraper conveyor placed in an inclined position lifts the material out of the liquid contained in the bin. From the top end of the scraper conveyor, the material falls into the pyrolysis reactor. To limit the entry of oil from the feed device into the reactor, there are, in the inclined surface of the scraper conveyor of the pyrolysis apparatus, one or several grooves, along which oil can flow back into the liquid basin.

There can also be, attached to the scraper conveyor of the feed device, a timer which sequentially consecutively starts and stops the forward movement of the conveyor, such that the changes in the movement cause at least part of the liquid transported with the material to fall into the groove of the conveyor and flow back into the liquid contained in the feed bin. The pyrolysis apparatus reactor according to the invention is, most advantageously, relatively wide in the lateral direction and a scraper conveyor is used for moving the material. Thereby the material to be processed can be spread across a large area in the pyrolysis reactor, whereby the contact surface between the material to be processed and the hot base is as large as possible. The reactor has heating resistors for heating the substance contained in the reactor chamber. There can be heating resistors at least in the top surface and the bottom surface of the reactor chamber. Most advantageously, the heating resistors or the flame grate is below the level at which the material to be processed is in the reactor. This way it is possible to achieve a relatively even and advantageous temperature for processing the material. The reactor chamber has been thermally insulated with, for example, heat-resistant industrial MT or HT insulation wool or ceramic wool.

The processed material exits from the reactor chamber through the discharge opening to the outlet portion of the pyrolysis apparatus, where there is a discharge screw and a condensing collecting canopy. The vapour formed in the outlet portion in the reactor is condensed into liquid and recovered. Thanks to the discharge screw structure according to the invention, this can be prevented and the vapour can be condensed, in a controlled manner, into liquid that is recovered.

The application does not present a pyrolysis apparatus gas collector, the structure of which can vary. The gas collector can be, for example, a liquid-filled tub, in which has been placed a collecting member, such as another tub that has been turned upside down and equipped with a flotation device. Most advantageously, the tub of the gas collector can be equipped with upper and lower limit switches that control the gas outlet compressor connected to the gas collector such that the compressor sucks the gas accumulated in the other tub equipped with a flotation device into the pressure tank sequentially when the tub equipped with a flotation device has reached the permitted upper limit.

In the pyrolysis apparatus according to the invention, material can be fed into the process without having to shred it nearly as finely as with conventional air trap rotary feeder solutions. In addition, fibres, such as steel belt materials in car tyres, do not cause any problems in this case. This enables, in addition to a continuous process, significant energy savings as the need for shredding diminishes. In addition, if the process uses so-called catalyst chemicals, the use of liquid considerably facilitates the dosing of the chemical and the spreading of the substance and the catalyst can be in both pulverulent and liquid states.

In the solution according to the invention, electric energy can be used for heating the pyrolysis reactor, which means that the process heat can be adjusted with high precision and focused as even radiant heat on the reactor. In the solution according to the invention, the even temperature of the reactor improves the overall efficiency of the process and the quality of the end products

In the following, the invention is described using examples with reference to the appended drawings, in which

Fig. 1 shows a pyrolysis apparatus according to the invention.

Fig. 2 shows another pyrolysis apparatus.

Fig. 3 shows a cross section of the reactor chamber

Fig. 1 shows a pyrolysis apparatus 10 according to the invention, wherein the material to be fed is poured into the bin 21 of the feed device 20. The bin 21 contains liquid 22 that is suitable for the process in terms of chemical reaction properties. The liquid 22 is, most advantageously, a low-viscosity liquid that is as inert as possible, such as, for example, light fuel oil or water. In the bin 21 , the level of the liquid 22 is so high that the liquid 22 forms a gas trap in a similar way as a drain trap, for example. The scraper conveyor 23 located in conjunction with the bin 21 transports the material out of the bin 21 and transfers it into the process taking place in the reactor portion 30. The scraper conveyor 23 is sufficiently long and inclined and has at its bottom one or several grooves 24 or a gutterlike space along which the liquid 22 transported with the material and/or in the conveyor 23 can flow back into the bin 21.

The scraper conveyor 23 of the feed device 20 of the pyrolysis apparatus 10 is driven by a motor, which is not shown in the figure. The operation of the conveyor 23 can be controlled with a work-pause timer such that the movement of the conveyor is stopped from time to time. Thereby the material flow can be controlled such that the conveyor 23 is only moved for the desired length of time at a time, whereby only a small amount of material is transported forward quickly. During the movement, the material so to speak sways and is shaken, after which the conveyor stops for a moment, waiting for the liquid 22 transported with the material and/or the conveyor 23 to flow into the groove or gutter and back into the bin 21. After that, the scraper conveyor starts up again and the material transfer movement continues. When the material to be processed falls from the feed device 20 into the pyrolysis reactor 30, it hits the spreader 34 located in the feed channel. Thereby the material is spread across an area as large as possible on the base located in the reactor chamber. In Fig. 1 , the wide scraper conveyor transfers the spread material to the end of the reactor chamber, where it falls onto another similar base. After that, the scraper conveyor transfers the material to the opposite end of the reactor chamber at the discharge opening 41.

The pyrolysis reactor 30 of the pyrolysis apparatus 10 is formed by a reactor chamber, inside which is located a scraper conveyor 32. Heating resistors 33 that heat the pyrolysis reactor 30 have been located in conjunction with the reactor chamber. Fig. 1 shows the resistors 33 in the top wall of the reactor chamber and in the bottom wall in conjunction with the reactor chamber bottom 31. However, the heating resistors 33 or flame grates are most advantageously below the base levels on which the scraper conveyor moves the material to be processed. The heating resistors 33 are, for example, ceramic radiant resistors. The resistor output is controlled, for example, by a PID controlled control device, such as thyristor control or a semiconductor relay. The sensors of the PID controllers are not shown in the figure. The reactor chamber has been thermally insulated, for example, by coating it throughout with insulation 35, such as heat-resistant industrial MT or HT insulation wool or ceramic wool.

The material passes from the pyrolysis reactor 20 of the pyrolysis apparatus 10 through a discharge opening 41 into the outlet portion 40, from where the processed carbon is discharged through the outlet opening 59 of the outlet portion 40 with the close-pitch discharge screw 42. The discharge screw 42 is sufficiently long and more closely pitched at its end and so tight against the casing pipe 43 that when it is full of the carbon that has become fine-grained during the process, oxygen can no longer enter back into the chamber of the pyrolysis reactor 30 through the casing pipe 43. The discharge screw 42 is surrounded by a sandwich casing structure that has, at its core, with the exception of the final end, a casing pipe 43 that is open at the top and has, at its upper end, a roof structure 44 which is permeable to vapour. Above the roof structure 44 there is a steeply inclined, grooved or corrugated-steel-sheetlike collecting canopy which is cooled by a liquid-cooled outer casing. The vapour is condensed into the collecting canopy and flows along its inner surface into the casing pipe and to the bottom end of the inclined conveyor. From the bottom end of the casing pipe 43 starts a pipe 51 , formed by an oil trap bend, through which the liquid flows into the collecting system. According to the invention, some of the liquid collected can also be pumped back into the bin 21 of the feed device 20 through the pipe 26, because the scraper conveyor 23 can transport small amounts of liquid 22 out of the bin 21.

The removal and collecting of the gas generated in the reactor of the pyrolysis apparatus 10 takes place using the condensing column and the gas collector, which have not been presented in the figure.

As pyrolysis is often used to process materials that conduct heat poorly, such as shredded rubber, polyurethane, hay or sawdust in the production of biocarbon, it is advantageous to keep the heat transfer distances small, i.e., most advantageously, below 30 cm. According to the invention, the scraper conveyor structure makes it possible to create advantageous temperature conditions in the pyrolysis chamber.

In the pyrolysis apparatus feed device according to the invention, the feeding of the feed material has been arranged air-tightly such that no air can enter into the process through the feed device. For this purpose, the bin of the feed device has an air trap which contains liquid. Liquid is added to the air trap in the beginning. During use, some liquid rises with the feed screw, but thanks to the sequential operation of the material conveyer, the majority of the liquid is caused to flow back into the bin of the feed device. Thanks to the oil return function in the feed device, the condensing collecting canopy in the outlet device and the advantageous method of heating the reactor, the efficiency of the pyrolysis apparatus according to the invention is good and its electric energy requirement is low.

If required, a small amount of the liquid, such as oil, collected in the process, can be pumped from the collecting tank back to the feed device to replace any volume of liquid that may have exited with the conveyor of the feed device, in order for the air trap to remain operational with the help of the liquid. The volume of replacement oil required for the air trap can be, for example, 10% of the oil obtained in the process.

What is essential for the pyrolysis apparatus according to the invention is that the material to be processed can be spread across an area as large as possible in the reactor chamber. Thereby the transfer of heat into the material to be processed is as efficient as possible.

LIST OF REFERENCE NUMBERS

10 Pyrolysis apparatus

20 Feed device

21 Feed bin

22 Liquid

23 Scraper conveyor

24 Groove

26 Pipe

27 Feed opening

30 Pyrolysis reactor

31 Reactor chamber bottom

32 Scraper conveyor

33 Heating resistor

34 Spreader

35 Insulation

40 Outlet portion

41 Discharge opening

42 Discharge screw

43 Casing pipe

44 Screw conveyor

47 Groove

51 Pipe

59 Outlet opening