WO2009130524A1

WO2009130524A1 - Pyrolytic apparatus and method

Info

Publication number: WO2009130524A1
Application number: PCT/HU2009/000036
Authority: WO
Inventors: Sándor LUCZE
Original assignee: ENERGUM DEUTSCHLAND GmbH; Lekrinszki Balazs Barna
Current assignee: ENERGUM DEUTSCHLAND GmbH; Lekrinszki Balazs Barna
Priority date: 2008-04-24
Filing date: 2009-04-23
Publication date: 2009-10-29
Anticipated expiration: 2010-10-24
Also published as: HU0800261D0; HUP0800261A2

Abstract

The invention is a pyrolytic apparatus comprising a reactor unit (50) having a heated pyrolysis area and a condensation unit (51) condensing pyro-oil from pyro- gas by cooling down the pyro-gas recovered from a material in the pyrolysis area. According to the invention, after passing trough the condensation unit (51) at least a part of the pyro-gas is re-circulated into the pyrolysis area of the reactor unit (50). The invention further relates to a pyrolytic method carried out with the apparatus.

Description

PYROLYTIC APPARATUS AND METHOD

TECHNICAL FIELD The present invention relates to a pyrolytic apparatus comprising a reactor unit with heated pyrolysis area and a condensation unit condensing pyro-oil from a pyro-gas by cooling the pyro-gas recovered from a material in the pyrolysis area. Further, the invention relates to a pyrolytic method based on the apparatus.

BACKGROUND ART

Waste management is more and more becoming a vital industry of our days. Due to our way of life, an immense amount of non-biodegradable, or very slowly biodegradable waste is being produced in a continuous manner. Both storage and disposal of such waste is possible only at high costs, thus it is one objective of waste processing to recover the more and the better quality recyclable material.

One such process for the recovery of recyclable materials is the oxygen-free thermal decomposition, i.e. pyrolysis, in which so called pyro-gas and/or pyro-oil is produced by thermal decomposition of waste comprising macromolecule organic compounds (e.g. rubber, plastics). The ratio and the chemical composition of the end product depend on the base materials (i.e. the type of waste) as well as on the conditions of pyrolysis. For the pyrolysis, first the waste is usually shredded, then introduced into a pyrolysis reactor, where it is heated for a longer period of time in an oxygen-free environment, and the resulting pyro-gas releases (i.e. vapors and gases formed during pyrolysis) are conducted into, and condensed in a cooling system, and thus pyro-oil is obtained, which then can be used, for example, as fuel oil or as engine fuel after further processing. Following condensation of vapor, the remaining gases may also be put to several uses. The soot remaining after waste evaporation is a recyclable material, that can be used as additive agent, for example, in rubber production.

From the aspect of continuity of the pyrolysis process, we can distinguish between batch (periodical) pyrolysis apparatuses and continuous pyrolysis apparatuses. In the case of batch pyrolysis apparatuses, the pyrolysis reactor is filled with waste, serving as base material, and after a certain period of heating, the residual soot and other substances are removed. Within certain boundaries, the reactor is heated, then cooled down, which entails significant loss of energy. Beyond loss of energy, the material of the reactor is likely to fail prematurely due to the fluctuations of heat, in consequence of the frequent changes of shrinking due to the cooling cycle and expansion due to the heating cycle. The intense change of volume on account of the fluctuation of heat will cause a rapid fatigue of the material structure; and the time spent on filling-up and emptying will greatly constrain productivity. On the other hand, in the case of a continuous pyrolysis reactor, the waste is continuously introduced into the pyrolysis reactor, and the residual material is continuously discharged from the reactor. The pyro-gases, and pyro-oils recovered thereof, are also continuously produced, whilst the system requires less supervision, and does not require to stop and to restart the processes repeatedly. The present invention primarily relates to such continuous pyrolysis apparatus.

It is an important aspect in the development of a reactor of continuous pyrolysis apparatus, that the waste should remain in the reactor for an adequate period of time at an adequate temperature. This can practically be attained by the use of a reactor containing several reactor chambers, where the individual chambers can be heated to different temperatures. In the case of pyrolytic apparatus comprising several reactor chambers, the chambers are typically arranged following each other, and the waste is forwarded through the chambers by means of a kind of material forwarding device, for example a pulley. An apparatus comprising such a pyrolysis reactor is disclosed in US 4,983,278.

A disadvantage of known pyrolytic apparatuses and methods is the difficulty of implementing rapid extraction of pyro-gases, which would be necessary for more rapid pyrolysis processes. By keeping the produced pyro-gases in the pyrolysis area will result in the formulation of long-chain molecules, which reduce the quality of pyro-oil. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a pyrolytic apparatus and method that overcome the above-described disadvantages of the solutions of prior art. It is a further object to establish a pyrolytic apparatus and method that is simple to operate at low-cost, and which can most efficiently utilize the produced pyro- gases.

The invention has been achieved in light of the recognition, that after condensation of pyro-oil from the produced pyro-gas a liquid-free pyro-gas remains, which is from all aspects (composition, temperature) suitable for accelerating the extraction of the newly formed pyro-gases rich in liquid by re-circulating it into the pyrolysis area.

The invention, therefore, relates to a pyrolytic apparatus according to claim 1 , and a pyrolytic method according to claim 7. Preferred embodiments of the invention are defined in the dependent claims.

It is the benefit of the present invention, that by continuous and controlled recirculation of the ,,dry" pyro-gas, it can quickly remove the produced gases. This accelerates the process of pyrolysis and reduces the formation of long-chain molecules, thereby improving the quality of pyro-oil and soot.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of a preferred embodiment is presented herebelow with reference to the accompanying drawing, where

Fig. 1. is a schematic diagram of a pyrolytic apparatus according to the invention.

MODES FOR CARRYING OUT THE INVENTION

It has been an important aspect when creating the apparatus of the present invention, that the waste should remain in the reactor for an adequate period of time, at an adequate temperature. The apparatus has, therefore, been constructed in a way that it comprises three reactors 1 , 2, 3, which can operate at different temperatures. The soot remaining from pyrolysis is a valuable recyclable material, the quality of which is important to be maintained at a most suitable level in the long run. The apparatus has been constructed so that an artificial gas circulation is conducted through the pyrolysis area of the reactors so as to accelerate evaporation of the gases produced in the course of the pyrolysis.

The apparatus according to the present invention, therefore, comprises a reactor unit 50, which preferably comprises three reactors 1 , 2, 3 arranged one above the other and connected with each other in a series. The reactor unit 50 comprises a waste input joint 7, an output opening 10, a pyro-gas recirculation joint 21, and two gas outlet joints 23, 24. For the gravitational flow, a flexible connection is ensured by compensators between reactors 1-3. All three reactors 1-3 are equipped with a device to ensure material forwarding from the waste input in the direction of output.

The material to be pyrolyzed, preferably waste, examples of which may contain automotive rubber tires, plastic foils, plastic objects, parts or an arbitrary mixture thereof, is shredded into 2-5 cm pieces prior to feed. The material to be pyrolyzed, i.e. waste to be processed is continually introduced into the waste input joint 7 located on the body of reactor 1. The material to be pyrolyzed passes from the waste input joint in the direction of the output opening 10 along the marked arrows. In the reactor chamber 1a of reactor 1 , a material forwarding means is arranged, which is preferably formed as a spiral belt mounted onto a mandrel, and by the means of which the waste is conveyed longitudinally in one direction (from left to right in the drawing), whilst being turned and stirred by mixing blades mounted on the spiral belt. From reactor 1 , waste passes through a flow profile 8 by means of gravitation into reactor 2. Preferably identical spiral belts are arranged in reactors 1 and 2; in the case of reactor 2 waste is forwarded thereby from right to left.

The material passes from reactor 2 into reactor 3 through a flow profile 9. In reactor 3, contrary to the above, mixing blades fixed to mixing arms mounted onto the mandrel carry out the intense stirring, as well as force linear movement of the material from left to right. The evaporated waste, which has been transformed into soot, reaches the temporary collector tank connected to the output opening 10 of reactor 3. In this way, the waste entering the reactor unit 50 has to pass through the entire length of reactor chambers 1a-3a so as to pass into a lower chamber through the gravitational flow profiles 8, 9. From the collector tank the soot is periodically emptied into further units through a valve.

Pyrolysis takes place in a continuous manner in the reactor unit 50, whilst the waste is forwarded by means of the material forwarding means arranged within the reactor chambers, and the material passes from the upper chambers into lower arranged chambers via gravitation. The period of time spent in the individual chambers as well as the temperature set in the individual chambers greatly depend on the type of waste. The temperature of pyrolysis is typically in the range between 400 and 800 °C, which may differ in the individual chambers and the period of time spent in the individual chambers typically lasts between 15 and 25 minutes, however, these values may significantly differ depending on the type of material to be pyrolysed.

The reactor unit 50 is heated by means of the heating mantles 4-6 positioned on the reactors 1-3. Preferably heating mantles 4-6 are in communicating connection with each other, however are not in communicating connection with the pyrolysis area. Heating of the reactors 1-3 is conducted from heating pipe inputs 11 of reactor 3, and from a heating pipe input 13 of reactor 2 to a flue gas output joint 15 along the arrows marked in the heating mantles 4-6. Pyrolysis takes place in the longitudinal chambers 1a-3a of the reactors 1-3, comprising part of the pyrolysis area. Preferably, the reactor chambers 1a-3a are 3-10 m in length with an inner diameter of preferably between 20 cm and 1 m.

Preferably, the reactors 1-3 require different temperature settings. Reactor 1 requires the lowest, while reactor 3 requires the highest temperature. By utilising a thermic afterburning heat, reactors 1-3 are heated via heating of mantles 4-6 surrounding the bodies of reactors 1-3, via distributing heating pipes by means of forced circulation. The main supply heating pipe is divided into three parts, two of which are connected to reactor 3 via the heating pipe inputs 11. Via forced circulation, the non-utilized heat passes through the connection profile 12 arranged on the upper part of the heating mantle 6 into reactor 2, where flue gas is freshened through heating pipe input 13 by a third heating pipe. The heating flue gas passes by means of forced circulation into reactor 1 through connection profile 14 without being freshened. Flue gas leaves reactor 1 through the upper flue gas output joint 15. In this way, reactor 1 is able to utilize the waste heat, that reactor 2 is unable to utilize.

Heating of the reactor unit 50 is supplied by a thermic afterburner 33 comprising a burner, in this way keeping contamination of flue gas to a minimum level. The heating energy is produced from the gas recovered through pyrolysis. The initial operation of the system requires the use of, for example, pipeline gas. After a few hours of operation, however, pipeline gas is no longer necessary, since sufficient amount of pyro-gas will be produced for the system to become self-supporting. The hot flue gas passes along the heating route 40, via the main pipe to the reactor unit 50, where divided into three portions, of which two branches are connected to the heating pipe input 11 of the reactor 3, whilst the remaining branch is connected to the heating pipe input of reactor 2. After delivering its heat energy, flue gas leaves through the flue gas output joint 15. In this way, the outside mantle heating is preferably formed as an interrelated system comprising at least one burner, heating the reactor chambers 1a-3a.

The apparatus operates at nearly atmospheric pressure. According to the present invention decomposition by pyrolysis process takes place in an artificially produced gas circulation. The gas route 41 illustrating the passing of gas is marked by a dashed line in Fig. 1. It is a benefit of the present invention, that by continuous, controlled gas circulation the formed gases can be eliminated quickly and formation of long-chain molecules is reduced, thereby improving the quality of other by-products, such as of pyro-oil, for example.

The pyrolytic apparatus according to the present invention, therefore, comprises a reactor unit 50 comprising heated pyrolysis area and a condensation unit 51 condensing pyro-oil from pyro-gas by cooling down pyro-gas recovered from the material in the pyrolysis area. According to the invention, after passing through the condensation unit 51 at least a part of the pyro-gas is re-circulated into the pyrolysis area of the reactor unit 50.

According to the preferred embodiment illustrated on the figure, the reactor chamber 3a of reactor 3, which forms a part of the pyrolysis area, is equipped with a pyro-gas re-circulating joint 21 , through which the liquid-free, so-called ,,dry" pyro-gas conducted through the condensation unit 51 is re-circulated and introduced in a controlled manner by means of a ventilator 30. By taking hold of the pyro-gas rich in liquid formed in reactor chamber 3a, the pyro-gas passes through the connection gas pipe 22 arranged for unhindered flow into reactor chamber 2a, where taking hold additional pyro-gas rich in liquid, it leaves through the gas output joint 23. En route, the gas is circulated in a countercurrent to the material to be pyrolysed and bumps against several surfaces, resulting in the condensation of the major part of the granule particles while the gas passes on. The gas leaving through the gas output joint 23 reaches the condensation unit 51 through a vapor pipe being accelerated by the suction effect of the ventillator's 30 suction side, thereby realizing a circular connection. The gas formed in reactor chamber 1a reaches through a separately arranged gas output joint into a cyclone 25 known per se, where water being evaporated from the waste and transported by pyro-gas condenses. Decomposition does not yet take place in reactor chamber 1a. The gas leaving the cyclone 25 also enters the condensation unit 51 through the above mentioned vapor pipe.

The condensation unit 51 illustrated on the figure comprises a first and a second oil condensation column 26, 27. Initially, the pyro-gas enters the column 26, where moving upwards from the bottom of the tower and bumping into the wall of the liquid-cooled column, first the fraction of high boiling-point condenses and accumulates in the so-called ,,boiler" part. From the gas passing on, the condensing fraction already with lower boiling-point re-drips into a drip tray arranged at the upper part of the column 26. The pyro-gas emerging from the upper part of the column 26 passes into the bottom of the column 27 through a connection pipe. By moving upwards from the bottom of column 27 and passing two drip trays, the gas cools down to such an extent that no additional liquid material condenses. The gas emerging from the upper half of column 27 is conducted through a transfer pipe into a scrubber 28. Moving upwards in the gas scrubber, and passing through a caustic solution injected at two levels of jet dispersers, the gas is decontaminated. The gas emerging from the scrubber 28 is conducted into the cyclone 29, where the taken water drops condense. Then, the gas pipeline connected to the discharge side of the ventilator 30 divides into two branches, where a part of the gas passing through a control-valve towards the pyro-gas re-circulating joint 21 of the reactor 3 re-enters the cycle. The other part of the gas enters the compressor 31 , from where in a compressed state it passes towards a gas tank 32. From the gas tank 32, the gas passes into a thermic afterburner 33, where it is burned, thereby providing thermic energy for the serial reactor, i. e. the portion of pyro-gas, which is not re-circulated into the pyrolysis area is used for heating the reactor unit 50.

In columns 26 and 27, for example four fractions separate as condensates, the accumulation of which is dependent upon the planned utilization. For heating purposes, for example, those can be mixed resulting in high calorific value oil. The oil accumulated in the drip trays and accumulation parts arranged in the columns 26 and 27 is conducted into oil accumulation tanks 36 through water separators 35. Pyro-oil is periodically transferred via an oil route 43 from the oil accumulation tanks 36 into temporary accumulation tanks 39 by means of a pump 38. The tank divided into cells ensures settling and then transfer of oil into other tanks.

In the course of pyrolysis, a minimum of water arises, moreover the waste also contains water. Water is an undesirable material in the technology, therefore, it needs be separated and extracted from the cycle. Separation is mainly made by means of a cyclone 25 condensing the gas formed in the reactors 1 and 2.

Additional water is separated by means of the water separators arranged at columns 26 and 27. Here, the separated water is collected in water accumulation tanks 37. Water is then conveyed from the water accumulation tanks 37 by means of pumps 38 in controlled amounts via the water route 34 into the soot-cooler, where cooling of soot is aided by vaporized water. In the accumulation tank connected to the reactor 3, high temperature soot accumulates, which cannot be processed at high-temperature. As a further step of the present technology, the soot-cooler completes the cooling of soot to a processable temperature. Preferably, the soot-cooler is a batch operating apparatus. Cooled through its outer mantle by a cooling-liquid, an inside stirring unit completes the turning of soot. Filling up of the soot-cooler locks the filling- valve, and intense stirring starts, while a controlled amount of water accumulated by the technology is vaporised onto the soot. After a few minutes of cooling, the soot is discharged into the throat positioned underneath the soot-cooler 34, from where the soot is forwarded, after being measured, for further processing by means of, for example, a worm-conveyor.

Of course the invention is not particularly limited to the preferred embodiment as presented in full detail, but may comprise further modifications and alterations within the scope of the following claims.

The number and position of burners connected to the mantle-heating greatly depend on the thermal decomposition parameters of the waste to be pyrolysed. In the preferred embodiment illustrated herein, the reactor chambers 1a-3a are arranged directly one above the other, which carries the benefit of a compact, space- and material-saving construction, however, it is evident, that the benefits according to the present invention can also be realized in the cases of any arbitrarily arranged chambers. Also it is not absolutely necessary that the reactor chambers of 1a-3a should be arranged horizontally, or that they should be parallel to each other. The number of pyrolysis reactor chambers 1a-3a may also vary according to specific needs.

Claims

1. A pyrolytic apparatus comprising a reactor unit (50) having a heated pyrolysis area and a condensation unit (51) condensing pyro-oil from pyro-gas by cooling down the pyro-gas recovered from a material in the pyrolysis area, c h a r a c t e r i z e d in that after passing trough the condensation unit (51) at least a part of the pyro-gas is re-circulated into the pyrolysis area of the reactor unit (50).

2. The apparatus according to claim 1 , characterized in that after passing through the condensation unit (51) the pyro-gas is divided into two parts, and the part of the pyro-gas not re-circulated into the pyrolysis area is used for heating the reactor unit (50).

3. The apparatus according to claim 2, characterized in that the pyrolysis area comprises at least one longitudinal reactor chamber (2a, 3a) having an outside mantle-heating not in communicating connection with the pyrolysis area; in which reactor chamber (2a, 3a) a material forwarding means is arranged for forwarding the material longitudinally in one direction, and the re-circulated pyro-gas is circulated in the reactor chamber (2a, 3a) in a countercurrent to the direction of the material forwarding.

4. The apparatus according to claim 3, characterized in that it comprises reactor chambers (1a, 2a, 3a) arranged one above the other, through which the material is being forwarded by means of gravitation, and the re-circulated pyro-gas is circulated through at least two reactor chambers (2a, 3a) in a countercurrent to the direction of the material forwarding.

5. The apparatus according to claim 4, characterized in that it comprises three reactor chambers (1a, 2a, 3a) arranged one above the other, and the re-circulated pyro-gas is circulated through the lower two reactor chambers (2a, 3a), where the outer mantle-heating is constructed as an interrelated system comprising at least one burner to heat the reactor chambers (1a, 2a, 3a).

6. The apparatus according to any of claims 1 to 5, characterized in that it comprises a scrubber (28) decontaminating the pyro-gas after passing through the condensation unit (51) and prior to re-circulation; and a cyclone (29) extracting water drops from the pyro-gas.

7. A pyrolytic method, in which pyro-oil is condensed from a pyro-gas by cooling down the pyro-gas recovered from a material in a heated pyrolysis area, c h a r a c t e r i z e d in that after condensation of the pyro-oil at least a part of the pyro-gas is re-circulated into the pyrolysis area.

8. The method according to claim 7, characterized in that after condensation of the pyro-oil the pyro-gas is divided into two parts; and the part of the pyro-gas not being re-circulated into the pyrolysis area is used for heating the pyrolysis area.

9. The method according to claim 8, characterized in that the pyrolysis area comprises at least one longitudinal reactor chamber (2a, 3a) equipped with an outer mantle-heating not in communicating connection with the pyrolysis area; in which reactor chamber (2a, 3a) the material is forwarded longitudinally in one direction, and the re-circulated pyro-gas is circulated in the reactor chamber (2a, 3a) in a countercurrent to the direction of the material forwarding.

10. The method according to claim 9, characterized in that the pyrolysis area comprises reactor chambers (1a, 2a, 3a) arranged one above the other, through which the material is forwarded by means of gravitation, and the re-circulated pyro-gas is circulated through at least two reactor chambers (2a, 3a) in a countercurrent to the direction of the material forwarding.

1 1. The method according to any of claims 7 to 10, characterized by applying a scrubber (28) decontaminating the pyro-gas after condensation of the pyro-oil and prior to re-circulation, and a cyclone (29) extracting water drops from the pyro-gas.