WO2005021685A1

WO2005021685A1 - Process and installation for thermal cracking used in decomposing rubber and plastic waste

Info

Publication number: WO2005021685A1
Application number: PCT/IB2004/002738
Authority: WO
Inventors: Jenõ TIKOS; András URBÁN
Original assignee: S.C. Pyroinvest S.A.
Priority date: 2003-08-27
Filing date: 2004-08-23
Publication date: 2005-03-10
Also published as: MD3343C2; MD3343B1; EP1668092A1; RO120487B1

Abstract

The invention relates to a thermal cracking process of decomposing rubber and plastic waste and to an installation for implementing this process. According to the invention, the process consists in that thermal decomposing of rubber and plastic waste of a dimension between 15 and 200 mm is made on the bases of its own energy by ebbing a part of the cracking oil thus obtained, which is used for heating the waste from the reactor and for reactor heating and pre-heating as well. According to the invention the installation consists of: a cracking reactor (1), equipped with a worm-gear shape mixer (15), with a vertical axis (23), an a driving-gear system (24,10,21) fixed on the cylindrical wall and on lower conical part of the reactor, an ebbing distribution unit (39,22), a heating space (2) where are placed two spiraled tubular pre-heaters (5) through the ebbing oil obtained after the thermal decomposing of rubber waste flows and some blades (4) for directing the burning products, on the outer wall of the reactor two burners (3) are tangentially disposed and a pipe for evacuation the burning products (26) which the ebbing pre-heater (27) is wrapped and in which the ebbing oil flows, on the upper part the reactor (1) being equipped with an evacuation pipe (6) through which the flow of matter obtained from the thermal decomposing of the waste is passed in a separation cyclone, which at its turn is coupling to a gases cooling-rectifying, gas scrubbing column and a gas condensing apparatus, the obtained products being directed to industrial use, and a part to ebbing and using in the technological process.

Description

Process and installation for thermal cracking used in decomposing rubber and plastic waste.

The invention relates to a thermal cracking process of decomposing rubber and plastic waste and to an installation for obtaining some hydrocarbons that can be industrially used.

There are known different processes, methods and apparatuses used in thermal decomposing rubber and plastics; either by direct burning in furnaces at high temperatures and pressures, in fluidized-bed reactor or by pyrolising using horizontal drum reactors, such as Mannesman, Tosco- Goodyear, Krauss-Maffei, Kiener and others.

These processes and apparatuses have the disadvantage that they are high energy consumers and at the same time the waste needs to be minced beforehand into very small pieces between of 1-5 mm; the apparatuses are complex constructions, extremely expensive and causing serious ecological problems.

The horizontal drum reactors for pyroKsing are expensive, they need an investment, their automating is complicated and their maintenance is expensive and it requires high-qualified staff. It is also needed a preliminary processing of the waste and they are high-energy consumers. The technical problem solved by the invention consists of achieving a cracking technology and a reactor of special, simple construction, with a reduced energy use for the thermal decomposing of rubber and plastic waste for obtaining hydrocarbons that can be industrially used, without causing any ecological problems upon the environment. The process and the installation of thermal cracking for decomposing rubber and plastic waste with the purpose of obtaining some hydrocarbons that can be industrially used, according to the invention, elrminate the disadvantages of known processes and apparatuses, because the waste of dimensions between 15 and 200 mm are introduced and decomposed in a special vertical reactor. In its upper part the reactor is equipped with a worm-gear shape mixer, fixed on the cylindrical and conical wall of the reactor, powered from the lower part of the reactor anti clockwise. The reactor are one concentric heating shell, which contains a heating space where there are two gas burners fixed on the outer wall of the reactor and placed tangentially, two spiral pre-heaters from inside the heating space, and a pre-heater fixed to the burned gas evacuation pipe, wherein circulate the ebbing oil obtained as a result of the thermal decomposition of waste. On the outer wall of the reactor, inside the heating space, there are also fixed some burned gas directing blades; these gases leave the reactor through an evacuation pipe situated on the upper part of the reactor. Inside the reactor the waste are decomposed at a temperature between

450°C and 700°C and a pressure of 50 350 mbar in: 25....40% carbon black, with a 97% purity and granulation max. 10 mm and in 25-75% hydrocarbons with a density at 15°C between 0,7284....0,9474 kg/dm³, which leave the reactor in the upper part, passing through a separation cyclone, from where the heavy condense together with solid impurities enter back into the reactor and the gases obtained are passed through an installation of cooling, rectifying, scrubbing column and condensing the gases well known, directed for being industrially used such as: gas, cracking gasoline with a density at 15°C between 0,7284-0,8200 kg/dm³ and cracking oil with a density at 15°C between 0,8200-0,9475 kg/dm³. Part of the cracking oil is ebbed in an ebbing distribution chamber, situated in the lower part of the reactor, from where is arriving directly onto the rubber waste and the other part of it is reintroduced in the two tubular spiral heaters from inside the heating space and inside the pre- heater fixed to the gas evacuation pipe.

After the thermal decomposing of the waste started inside the reactor it is enough to maintain indirect heatmg by regulating the oil ebbing thanks to the special construction of the reactor, the heating system and the mixing system.

The solid products: carbon black and steel are evacuated in the lower part of the reactor, passing into a carbon black separator from where the carbon black of a 97% purity and a granulation between 1-10 mm is passed inside a container and directed for being used in industry. The invention, according to the present description, has the following main advantages: - simple construction, safe in functioning, easy maintenance and no highly qualified staff is necessary - total recovery of rubber waste - reduction of the pollution factor, by the circulating of reacting products - obtaining hydrocarbons which can be used in the industry - is an economic process, with reduced consume of energy - uses its own energy obtained within the system by ebbing obtained oil, for heating and preheating both the reactor and the rubber waste that are to be terminally decomposed. - by introducing the ebbing oil both inside the pre-heater and the spiral heaters, respectively directly inside the reactor the thermal transfer space is enlarged, the necessary time for decomposing temperature is very brief, this obtaining far superior efficiency compared to other known processes. - thanks to the special construction of the reactor it is enough to maintain the necessary temperature to decompose the rubber by regulating the ebbing - the rubber waste doesn't need a previous mincing into small pieces, removing thus the expensive devices necessary to achieve this goal which are high energy consumers.

Following is an example of the invention's accompanying, related to figures 1, 2, 3 which represent: Fig.l. - the side view and cross section view of the reactor Fig.2. - upper view over the reactor Fig.3. - technological process scheme The thermal cracking apparatus for decomposing the rubber and plastic waste for the purpose of obtaining some hydrocarbons in order to be used on an industrial scale, according to the invention, consists of vertical cracking reactor 1; on its cylindrical wall and on its lower conical part there is fixed a worm-gear shape mixer 15 with a vertical axis 23, with a driving-gear 24,10 with a supply system 8,18 and evacuation 9,19 with the heating space 2 where there are 2 spiral tubular pre-heaters 5, where the ebbing oil flows, oil obtained as a result of thermal decomposing of rubber waste, some blades 4 for directing burned gases, two burners 3, tangentially placed on the outer wall of the reactor, with an evacuation pipe for the burning products 26 around which the ebbing pre-heater 27 is wrapped up and an ebbing distribution unit 22, 39. The waste sized between 15-200 mm are introduced into the vertical reactor 1, through a supply system 8 and 18 situated on the upper part of the reactor and in which at a temperature between 430 °C...580°C and a pressure of 50...350 mbar, wherein the waste is terminally decomposed into carbon black and hydrocarbons, gases, cracking gasoline and cracking oil.

Due to the gas temperature and pressure a flow of matter is formed that leaves the reactor 1 in the upper part through pipe 6 passing through a separation cyclone 30 from where the heavy condense together with the solid impurities are reintroduced into reactor 1 and the gases obtained at a temperature of 220°C and 390°C through pipe 49 are passed through a well known cooling and rectifying installation 31,32,42 a gas scrubbing column 33 and a gas condensing 40. The gases are directed for industrial use, and the carbon black together with the solid waste are evacuated through the evacuating system 9 situated in the lower part of the reactor 1 in inside the separator 45 from where the carbon black of 97% purity and maximum 10 mm granulation is passed into a container 43 with the help of a pneumatic transporter 46.

The liquid hydrocarbons: cracking oil and cracking gasoline are collected into pre-containers 34, 35 and 36. Because in this phase the cracking gasoline contains the condensed water, this is separated in separator 51.

The cracking gasoline with a density between 0,7284 and 0,8200 kg/dm³ at 15°C is stored in the cracking gasoline container 38 from where through pipe 56 it is send to be stored.

The cracking oil with a density between 0,8200 at 0,9475 kg dm³ at 15°C is stored in the cracking oil container 37 from where part of it is redirected in the ebbing distribution unit 39, 22 and from there a part of the cracking oil is ebbed through pipe 13 in the lower part of the reactor 1, thus getting directly on the rubber waste and another part of the cracking oil is reintroduced through coupling 14 into the two spiral tubular heaters 5 from inside the heating space 2 and inside the pre-heater 27 fixed on the gases evacuation pipe 26, and the other part is directed through pipe 55 for being stored. After the thermal decomposing of the waste started in the reactor 1, thanks to its special construction and the one of the heating 3, 5, 27 and mixing system 15, 10, 21, 23, 24 it is enough to maintain the indirect heating of the reactor 1 through regulation of the ebbing oil.

Thus the thermal transfer space is much enlarged, the temperature needed for thermal decomposing is maintained and at the same time the hydrocarbons proportion between light and heavy fractions obtained as a cracking result can be adjusted. In this way are possible a 50 % reduction of the needed time for obtaining a temperature of about 450°C temperature at the thermal decomposing of rubber waste starts, time that is constant and independent of the volume of waste inside the reactor, increasing of installation efficiency at 99% and a reduction with 30-40% of energy consume as compared to other known technologies.

Claims

1. The thermal cracking process of rubber and plastic waste for obtaining hydrocarbons for being industrially used, wherein consists in a vertical reactor 1 with a special construction and for obtaining the thermal decomposing temperature of the waste and its maintain it uses its own energy by ebbing a part of the obtained cracking oil with no other previous mincing into small all pieces of the waste, adjusting at the same time the proportion between the obtained hydrocarbons.

2. The thermal cracking process, according to claim 1, wherein the ebbing oil is used for direct heating of the rubber waste from the reactor and for heating and pre-heating the reactor as well.

3. The thermal cracking process according to claim 1, wherein the proportion between the hydrocarbons is between 1/4 and 4/1 cracking gasoline/cracking oil, proportion that depends both on the chemical composition of the waste and the quantity of the ebbing oil.

4. The thermal cracking process, according to claim 1, wherein the size of the waste used in the thermal cracking process is between 15 and 200 mm.

5. The thermal cracking process, according to claim 1, wherein the needed time for obtaining the temperature for thermal cracking decomposing doesn't depend on the volume of the waste, it is constantly maintained by means of ebbing oil and gas.

6. The thermal cracking installation for decomposing the rubber and plastic waste for obtaining hydrocarbons made to be industrially used, consists of a vertical cracking reactor, equipped with a supply and evacuation system, separator of fractions, gases cooling- rectifying and condensing apparatuses, wherein the vertical reactor (1) is equipped with a worm-gear shape mixer (15), a vertical axis (23), a driving-gear system (24,10) fixed on the cylindrical wall and on the lower conical part of the reactor, a concentric heating space (2) where are placed two spiraled tubular pre-heaters (5) where flows through ebbing oil obtained as a result of the thermal decomposing of the waste and some blades (4) for directing the burning products (26) and on the outer wall of the reactor in the heating space (2) two burners (3) are tangentiaHy disposed, on the upper part there is a pipe for evacuating the burning products (26) which the ebbing pre-heater (27) is wrapped up and on the lower part a unit for ebbing distribution (22, 39).

7. The thermal cracking installation according to claim 6, wherein the reactor (1) has on the upper part an evacuation pipe (6) through the flow of matter resulted in the thermal decomposing process of the waste passes into well-known separation cyclone (30) which at its turn is coupling to a gases cool g-rectifying (31, 32), gas scrubbing column (33) and a gas condensing (40) apparatus, from where the obtained hydrocarbons are directed to be industrially used, the heavy condense together with the solid impurities from the separation cyclone (30) are ebbed in the cracking reactor(l).

8. The thermal cracking installation according to claim 6, wherein in the lower part of the reactor (1) there is a pipe (13) through which a part of the obtained cracking oil is ebbed by an ebbing distribution unit (22, 39) from where a part of the oil through the pipe (13) is ebbed directly on the waste, in the heating space (2) in the spiraled heaters (5) through the coupling (14) and in the upper of the reactor (1) in the pre-heater (27) wrapped up the evacuation pipe of the burned gases (26)

9. The thermal cracking installation according to claim 6, wherein for directing the burning products the heating space (2) of the reactor is equipped with blades (4).