COMBINED MICROWAVE PYROLYSIS AND PLASMA METHOD AND REACTOR FOR PRODUCING OLEFINS

Abstract

The invention relates to a pyrolysis method for recovering at least one component from a feedstock material using a thermal treatment. The feedstock material is delivered to a pyrolytic chamber (1), exposed to a controlled atmosphere, and heated to a treatment temperature of the at least one component in the pyrolytic chamber (1) by applying microwave energy. The pyrolysis breakdown products are separated by fractional condensation and a targeted component is decomposed in microwave plasma. The microwave plasma is generated such that plasma temperature is varied over a temperature range including a decomposition and/or cracking temperature of the at least one component.

Claims

1. Pyrolysis and plasma decomposition method for recovering at least one component from a feedstock material using a thermal treatment, wherein the feedstock material is delivered to a pyrolytic chamber, exposed to a controlled atmosphere, and heated to a treatment temperature in the pyrolytic chamber by microwave energy to breakdown the feedstock material into pyrolysis breakdown products, and wherein pyrolysis breakdown products are exposed to a microwave plasma, which is generated such that it generates a decomposition and/or cracking temperature of the at least one component.

2. Pyrolysis and plasma decomposition method according to claim 1, wherein the microwave plasma is generated by a microwave radiation at frequencies between 300 MHz and 40000 MHZ.

3. Pyrolysis and plasma decomposition method according to claim 1, wherein the microwave plasma is generated by pulsed microwave radiation.

4. Pyrolysis and plasma decomposition method according to claim 1, wherein the temperature in the pyrolytic chamber remains below 1200 C.

5. Pyrolysis and plasma decomposition method according to claim 1, wherein the feedstock material is a feedstock or waste material stream comprising plastics, mixed plastics, rubber products, polymer composites, naphtha oils, ethane gas, bio oils and/or tires.

6. Pyrolysis and plasma decomposition method according to claim 1, wherein the at least one recovered component is an oil, a hydrocarbon, a monomer and/or a chemical plasticizer.

7. Pyrolysis and plasma decomposition method according to claim 1, wherein the at least one recovered component is ethylene, propylene, methane, hydrogen, DL Limonene, isoprene, butadiene, benzene, toluene, o-xylene, m-xylene, p-xylene styrene and/or phthalates.

8. Pyrolysis and plasma decomposition method according to claim 1, wherein the feedstock material is tempered to around 252.9 C. to recover hydrogen, to around 161.5 C. to recover methane, to around 103.7 C. to recover ethylene, to around 47.6 C. to recover propylene, to around 4 C. to recover butadiene, to around 35 C. to recover isoprene, to around 80.1 C. to recover benzene, 110.6 C. to recover toluene, to around 138.3 C. to recover p-xylene, to around 139.1 to recover m-xylene, to around 144.4 C. to recover o-xylene, to around 145.2 C. to recover styrene, to around 178 C. to recover DL Limonene and/or to 300 C.-410 C. to recover phthalates.

9. Pyrolysis and plasma decomposition method according to claim 1, wherein volatile components extracted from the pyrolysis chamber are passed through a fractional condensation system.

10. Pyrolysis and plasma decomposition method according to claim 1, wherein olefins, particularly ethylene and propylene are produced by cracking feedstock material comprising polymer, naphtha, ethane gas and/or bio oils.

11. Pyrolysis and plasma decomposition method according to claim 1, wherein the feedstock material comprises a pyrolytic oil or gas and the feedstock material is subjected to a fractional condensation at a temperature range between 253 C. and 600 C. resulting in at least one condensation fraction.

12. Pyrolysis and plasma decomposition method according claim 11, wherein the at least one condensation fraction is subjected to a further fractional condensation isolate paraffins, naphthenes, olefins and/or aromatics.

13. Pyrolysis and plasma decomposition method according to claim 1, wherein the controlled atmosphere is a negative pressure environment applied in the pyrolytic chamber, particularly a pressure below 10 kPa.

14. Pyrolysis and plasma decomposition method according to claim 1, wherein the controlled atmosphere is defined by at least one reactive gas, particularly a gas selected from hydrogen, steam, carbon monoxide, methane, benzene or a mixture thereof.

15. Pyrolysis and plasma decomposition method according to claim 1, wherein a temperature of the microwave plasma is controlled by varying an amplitude and shape of microwave radiation pulses that generate the microwave plasma.

16. Pyrolysis and plasma decomposition method according to claim 1, wherein a temperature and microwave power input varies in successive zones of the pyrolytic chamber.

17. Pyrolysis reactor for recovering at least one component from a feedstock material using thermal decomposition, comprising a pyrolytic chamber for accommodating the feedstock material and at least one microwave generator as a heat source for heating the feedstock material to a pyrolysis temperature of the feedstock material, as well as a plasma treatment chamber with microwave generator to produce a microwave plasma, with a control unit, which comprises a microwave radiation control for generating a microwave plasma using microwave frequencies between 300 MHz and 40000 MHZ, and a temperature control controlling a decomposition temperature of the feedstock material.

18. Pyrolysis reactor according to claim 17, which comprises an active impedance matching circuit for plasma ignition in the plasma chamber.

Description

[0048] Preferred embodiments of the invention will be described in the accompanying drawings, which may explain the principles of the invention but shall not limit the scope of the invention. The drawings illustrate:

[0049] FIG. 1: a schematic diagram of a first example set up of a pyrolysis reactor according to the invention, and

[0050] FIG. 2: a schematic view of a second example set up describing a pyrolytic chamber of a pyrolysis reactor according to the invention.

[0051] In the following, two example embodiments of a pyrolysis reactor according to the present invention are described which are suitable to perform a pyrolysis method for recovering at least one component from a feedstock material using a thermal treatment according to the invention. In both of the embodiments, the pyrolysis reactor for thermal decomposition and/or cracking of feedstock materials, particularly pyrolytic oils, hydrocarbons, monomers and chemicals from feedstock and waste streams such as tires, plastics, mixed plastics, rubber products polymer composites, naphtha oils, ethane gas and bio oils, comprises a pyrolytic chamber 1 for accommodating the feedstock material. Further, the example embodiments of the pyrolysis reactor comprise at least one microwave generator having a microwave radiation source as a heat source for heating the feedstock material to a decomposition and/or cracking temperature of the feedstock material.

[0052] A process control unit, such as a programmable logic controller (PLC), is used to control the pyrolysis process according to the invention. Advantageously, the temperature control operates the microwave generator to sequentially vary or increase the temperature in the pyrolytic chamber 1. The control unit also comprises a microwave radiation control for generating a microwave plasma using microwave frequencies between 300 MHz and 40000 MHZ to the feedstock material, and a temperature control for controlling the decomposition and/or cracking temperature of the feedstock material inside the plasma reactor.

[0053] The two example embodiments mainly differ in the design of their pyrolytic chamber, while other features of the reactor and steps of the method are the same. Therefore, structural features of the reactor and explanations of method steps which are suitable for both example embodiments shall be regarded as interchangeable between the two example embodiments.

[0054] For example, for both example embodiments it is advantageous to define that the temperature range of the pyrolysis method extends between ambient and 1200 C., particularly between ambient and 1000 C. The example embodiments are suitable to pyrolyse a pyrolytic oil and subjecting it to a fractional condensation at a temperature range between 253 C. and 600 C. The pyrolytic chamber may comprise a controlled atmosphere in form of a negative pressure environment, particularly a pressure below 10 kPa, or the controlled atmosphere is defined by at least one reactive gas, particularly a gas selected from hydrogen, steam, carbon monoxide, methane, benzene or a mixture thereof. The example embodiments allow for the extraction of volatile gasses from the pyrolytic chamber and condensing the gasses into different fractional oils. In the same way other features and steps apply to both of the embodiments.

[0055] FIG. 1 shows an example embodiment of the pyrolytic reactor in the form of a continuous flow retort with an elongated design. For example, it may comprise a conveyor to deliver feedstock material to the pyrolytic chamber 1 and transfer the material through the chamber while components thereof are decomposed.

[0056] For example, complete tyres, plastics, rubber products and polymer composites can intermittently be fed into the pyrolytic chamber 1 through a feed port 6 at a first end of the chamber. An air lock system with means for purging of oxygen can be provided at the first end as well.

[0057] Pyrolysis gases are drawn off at intervals along the length of the pyrolytic chamber 1, wherein successive exit ports 2 are provided at zones of increasing chamber temperature and different gases or compounds can be collected though the exit ports. In the variant of FIG. 1, gases are collected from exit ports 2a, 2b and 2c at three positions located along the length of the chamber, which ports correspond to three different recovery components. Solid products may be discharged through an airlock system at an end of the pyrolytic chamber 1 and may be separated using a suitable method, such as a vibrating screen 5 or the like.

[0058] The control unit can regulate the microwave power input to the pyrolytic chamber and control the temperature of the feedstock material at various successive heat zones 10a, 10b and 10c along the pyrolytic chamber 1 in a sequentially increasing treatment temperature fashion. Also, the control unit comprises a microwave radiation control for generating a microwave plasma of variable energy at frequencies between 300 MHz and 40000 MHz inside the plasma reactor.

[0059] In the example pyrolysis reactor shown in FIG. 1 feedstock material is introduced into the feed port 6 at a first end of the pyrolytic chamber 1 by a conveyor and transported along the length of the pyrolytic chamber 1. In the course of sequentially increasing treatment temperatures the pyrolytic chamber and the feedstock material respectively are first heated to a first decomposition temperature of a first component of the feedstock material within a first heat zone by microwave heating. First products may be evacuated through a first exit port 2a.

[0060] The pyrolytic chamber 1 can be designed as a continuous reactor and the subsequent heat zones can merge into each other.

[0061] At a second end of the pyrolytic chamber 1 further recovery components or feedstock remnants may be discharged through the airlock system.

[0062] FIG. 2 shows a schematic view of a pyrolytic chamber 1 of a second example embodiment of the pyrolysis reactor according to the present invention. The reactor has the form of a batch reactor such as a pressure vessel that opens to accept a load of feedstock material such as rubber tyres. For example, the pyrolytic chamber 1 of the reactor is of circular shape and may be opened at the top of the circular chamber.

[0063] In the shown example embodiment the reactor is loaded with a single tyre 7. microwave plasma is applied to the pyrolytic chamber 1 through feed ports 6 in a roof of the chamber. Electrical elements or burning off of some of the pyrolysis products may provide heating of the chamber walls to assist with heating and to prevent condensation inside the vessel. The pulsed microwave plasma is introduced through a number of microwave feed ports 6 on the roof of the vessel that are arranged in positions and orientations that ensure a uniform distribution of microwave radiation in the chamber 1. The chamber may also be in the shape of an annulus where the central portion 8 is removed to reduce unoccupied volume in the pyrolytic chamber 1.

[0064] In the batch reactor the temperature of the feedstock material can be increased in heating steps to the decomposition or cracking temperature of differing components to be recovered. Condensate can be collected in a storage dedicated to that component, while switching between condensate storages for each step of the sequential pyrolysis process. During the process the reactor wall temperature can also be increased in heating steps to prevent re-condensation of the volatiles in the reactor. The temperature can be controlled by the control unit. In each heating step recovery components are extracted from the pyrolytic chamber 1 through the exit port 2 and can enter a condenser system.

[0065] The PLC also monitors the temperature of the material, reaction vessel and volatiles exiting the reactor at the gas exit ports 2, and at the various decomposition heat zones 10a, 10b and 10c along the length of the reactor. Online and offline analysis of the pyrolysis products may also be used to provide inputs to the control unit. Based on the data collected the process control unit regulates the microwave power input into the heat zones and the residence and travelling time of the material in the reactor. By varying the microwave powering the different heat zones of the reactor the material is heated to predefined temperatures corresponding to decomposition or cracking temperatures of differing material components. This allows these components to decompose or crack in their corresponding heat zone and the volatiles produced during the treatment of that component can be collected in a dedicated condenser and collection vessel. In subsequent heat zones the remaining material components are for example heated to successively higher decomposition or cracking temperatures, each time extracting the volatile components associated with the different material components and collecting it in separate condenser systems. This sequential decomposition of differing material components allows the different components produced to be collected separately. The volatile components produced during each pyrolysis step are decomposed in the pulsed microwave plasma reactor and the decomposition products collected in storage vessels where it may be isolated by distillation.

[0066] It is also an objective of the process to bypass the condenser system and subject all the volatile components formed during pyrolysis, to the plasma decomposition.

[0067] The pyrolysis method and the pyrolysis reactor according to the present invention relies on the fact that each of the material components present in a feedstock material has different boiling points and microwave absorption properties. The application of pulsed microwave plasma using frequencies between 300 MHz and 40000 MHZ to sequentially increase the temperature in the pyrolytic chamber over a temperature range including the decomposition and/or cracking temperature of recovery components ensures a high yield of recovery and high quality of the recovered components. Also, a broad variety of components can be recovered due to the wide range of possible treatment temperatures.

LIST OF REFERENCE NUMBERS

[0068] 1 pyrolytic chamber [0069] 2a,b,c exit ports [0070] 5 vibrating screen [0071] 6 feed port [0072] 7 rubber tyre [0073] 8 centre portion [0074] 10a,b,c heat zones