WO2020230157A1

WO2020230157A1 - Device for melting plastic waste specifically for plastic pyrolysis

Info

Publication number: WO2020230157A1
Application number: PCT/IN2020/050423
Authority: WO
Inventors: Suhas Dixit
Original assignee: Suhas Dixit
Priority date: 2019-05-10
Filing date: 2020-05-11
Publication date: 2020-11-19

Abstract

The present invention provides a melting device (100) for melting of waste plastics contaminated with solid materials and providing a molten plastic feedstock suitable for pyrolysis reaction. More specifically, the present invention provides a new process and melting device (100) for melting plastic waste before feeding to pyrolysis reactor that will effectively preventing the entry of undesired materials like metal, stone, hard material in the pyrolysis reactor according to industrial requirement. The improved melting device (100) for waste plastic pyrolysis plant comprises of agitated vessel (1), a tubular perforated channel (9), an outlet (5) to discharge the molten plastic feedstock suitable for pyrolysis reaction, an inlet (15) with means for dosing plastic melting medium, temperature sensor (7), impeller (6) and gaseous stream outlet (8), wherein device is providing a suitable molten plastic feedstock by process of melting in presence of wax or oil composition.

Description

TITLE OF THE INVENTION:

DEVICE FOR MELTING PLASTIC WASTE SPECIFICALLY FOR PLASTIC PYROLYSIS

FIELD OF INVENTION:

The present invention generally relates to a melting device useful in a pyrolysis plant for providing a uniformly melted feedstock. More preferably, the present invention provides a device for melting plastic waste before feeding to pyrolysis reactor that will effectively preventing the entry of undesired materials like metal, stone, hard material in the pyrolysis reactor according to industrial requirement. The present invention also provides a process wherein plastic waste is suitably mix with waste wax or oil by-product of pyrolysis plant to provide a preheated molten mass comprising of plastic material and hot medium that will save the energy required to start the pyrolysis plant and to save the thermal energy required to run the pyrolysis reaction as well.

BACKGROUND OF THE INVENTION:

The plastic products including Polypropylene, Polyethylene, polyolefin, Linear and Low-density polyethylene, Polystyrene, Polyamide, Polyvinyl chloride, Acrylonitrile butadiene styrene and so on. On one side, plastic makes our daily life more convenient, on the other side, they are great threat to the environment due to resistant to many natural processes of degradation and thereby polluting a land, waterways and oceans.

It has been proven that plastic waste recycling using pyrolysis (Thermal Degradation above temp. 350 °C) technique is only solution to convert plastic waste into energy, and plastic pollution can be avoided. Where, the pyrolysis would convert plastic into syngas and biochar, waste plastics back into usable oil, or waste into safely disposable substances. The main host of the plastic pyrolysis plant consists of extrusion system (Feeding in the absence of oxygen), pyrolysis system (Thermal Degradation at temp 350°C or more) and separation system (products condensation).

Firstly, the waste plastic has to be put into the feed system to avoid entry of oxygen in main pyrolysis reactor. There may be variations in the feeding methods used depending on the characteristics of the waste plastic. Soft plastics such as films and bags are often treated with a shredder and a hot melt extruder in order to feed them into the reactor because they would occupy a large volume of the reactor. The unlike virgin plastic waste (scrap material recovered from polyolefin processing during fabrication or other manufacturing techniques), the house hold or industrial waste plastic consists of different additives (undesired constituents) such as thin, thick and hard material, metal sheets, stone, dust, wood, which normally constitute the municipal waste stream.

Hence, sorting of additives/metal parts from the plastic feedstock is the first and most important task to achieve better quality of pyrolysis product with good yield. Wherein, the manual or mechanical sorted and crushed material is cut and graded into uniform size for ease of handling and melting using extruder or simple round bottom heated rector with stirrer and finally fed into a pyrolysis reactor maintained at a temperature of about 200°C to 400°C, or more.

KR101289583B1 discloses a method and apparatus for thermal catalyst conversion of waste material into a reusable fuel, and delivers the molten waste material to one or more pyrolysis chambers through a heated and valved manifold.

Further, during feeding operation, the mixed waste plastic feedstock is fed from feeding systems into a stirred and heated pyrolysis chamber, such as extruder, piston type feeder and Screw Feeder. A hot melt extruder (a Melter) acts as an airlock to exclude oxygen and also to preheat and melt the polymer, so less energy input is required in the main chamber. The pyrolysis vessel operates at a constant level of 60% and the head space purged with nitrogen gas. A catalyst such as layered silicate catalyst, 5-10% by volume is added to the plastic melt to give a catalytic cracking reaction in pyrolysis reactor.

Despite the significant importance of hot melt extruder from which the melted waste plastic is fed into a pyrolysis plant, the extruder is not efficient to resist the entry of additives which are very small and not sorted out at primary stage such as stone, metal pieces into a pyrolysis reactor, which create problems in the mechanical functioning of the pyrolysis reactor as well as hampers the quality of final pyrolysis oils and lubricants.

Major problems associated with convention extrusion system, Screw Feeder and Piston type feeding system are listed below:

- frequent maintenance & cleaning of the extruder due to metal and stones present in the plastic waste. Once the extruder screw is damaged, repairing and replacing extruder screw can take lot of time resulting into lost production.

-it is a costly method of feeding plastic into the reactor, because electricity is used for melting the plastic.

- It is difficult to feed laminates or flexible carry bag type plastic using the extruder.

-It is difficult to feed the plastic waste without considerable size reduction stones and metal inside the plastic waste result into damage to the size reduction device like grinder or shredder.

- Cannot prevent the entry of chlorine content present in PVC into the reactor.

-It is difficult to feed plastic waste without considerable size reduction stones and metal inside the plastic waste result into damage to the size reduction device like grinder or shredder.

- Plastic enters the reactor in solid form which reduces the overall heat exchange capacity of the reactor.

Additionally, the present invention also provides a process wherein plastic waste is suitably mix with waste wax or oil by-product of pyrolysis plant to provide a preheated molten mass comprising of plastic material and hot medium that will save the energy required to start the pyrolysis plant and to save the thermal energy required to run the pyrolysis reaction as well.

In the light of the aforementioned discussion there exist a need a system and method that would overcome the above-mentioned problems in pyrolysis of plastic waste.

Hence, the present invention has been made in consideration of the above- described circumstances, and an objective thereof is to provide a melting device for treating sorting of additives present in plastic waste feedstock prior to feeding into a pyrolysis plant, the said device simultaneously capable of uniform melting of waste plastic material, and advantageously avoiding entry of very small metal and hard materials into pyrolysis plant.

Another advantage of present invention is eliminating the chlorine content in pyrolysis reactor.

Regarding the undesired constituents, chlorine is one of the key components in pyrolysis, because significant corrosion can be caused by chlorinated components during pyrolysis. Another problem is that the chlorinated components can poison the catalysts not only during the pyrolysis, but also in further application of pyrolysis oil.

Plastic waste comprising Polyvinyl chloride has more chlorine content. PVC has a key role in the plastics industry and the occurrence of PVC in streams of municipal plastic wastes is very common. On the other hand, the reduction of chlorinated compounds in pyrolysis product obtained from PVC containing raw materials is an unsolved problem. For this problem, the present invention provides an in-situ reduction in the concentration of chlorine compounds, wherein the present invention efficiently separating a chlorine contents from PVC waste feedstock, each alone or mixed with other plastics before entering into pyrolysis reactor. SUMMARY OF THE INVENTION:

It is an objective of the present invention to provide a device for melting plastic waste specifically useful in a polymer pyrolysis for restricting entry of undesired constituents such as stone, metal particles, sand, wood and allowing only plastic waste feedstock in a reactor with greatly reduced chlorine contents.

It is another objective of the invention to provide a process comprising incorporation of suitable wax or oil as melting medium for plastic waste and device with ease of sorting undesired constituents from plastic waste feedstock for converting a municipal, industrial, hazardous, medical plastic waste to useful energy with greatly reduced air pollution and plastic pollution.

According to the present invention there is provided with melting device (100) for melting of waste plastics contaminated with solid materials and providing a molten plastic feedstock suitable for pyrolysis reaction.

In a preferred embodiment, a melting device as a present invention comprising of:

- a agitated or fluidised vessel (1) having temperature controlling jacket (2) connected to an inlet and outlet for the heat transfer medium for providing temperature control to said agitated or fluidised vessel,

- a tubular perforated pipe or basket (9) extending inside the said agitated or fluidised vessel and connected at top to an inlet (10) for the waste plastic to be melted and an outlet (11) at the bottom or top for solid particles which remained undissolved,

- an outlet (5) to said agitated or fluidised vessel for melted plastic feedstock and operable under air lock feeding means;

-an inlet (9) for introducing suitable melting medium into vessel (1),

-a temperature sensor (7) probe for recording the temperature inside said agitated or fluidised vessel,

-an impeller means (6) for providing a stirring,

-an outlet (8) for gaseous stream; Characterized in that the said tubular perforated pipe or basket for enabling only molten plastic to flow in residence time during treatment into the agitated or fluidised vessel and entrapping a solid undissolved contaminant materials.

Wherein a tubular perforated pipe or basket is configured in vertical or in slanting position with respect to the hight of said agitated or fluidised vessel and the perforations on tubular perforated pipe or basket are evenly spaced.

A tubular perforated pipe or basket inlet for the waste plastic to be melted is configured with hopper for feeding waste plastic under air lock feeding means. Additionally, a tubular perforated pipe or basket inlet for the waste plastic to be melted is configured with means for dosing plastic melting medium.

Further, an agitated or fluidised vessel is provided with means for dosing plastic melting medium selected from oil, wax or any organic solvent or like.

The present invention also provides a process wherein plastic waste is suitably mix with waste wax or oil by-product of pyrolysis plant to provide a preheated molten mass comprising of plastic material and hot medium that will save the energy required to start the pyrolysis plant and to save the thermal energy required to run the pyrolysis reaction as well.

Hence, the present invention is provided by a melting device which is capable of processing a plastic feedstock such as hazardous waste, municipal waste (MSW), and other plastic waste forms into good quality feedstocks that are suitable for processing into pyrolysis reactor without risk of mechanical misfimctioning of the pyrolysis reactor as well as hampering the quality of final pyrolysis oils and lubricants.

Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components. BRIEF DESCRIPTION OF DRAWINGS:

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:

Figure No. 1: Illustrates a melting device (100) of the present invention having tubular pipe.

Figure No. 2: Illustrates a melting device (100) of the present invention having flexible mesh basket and outlet at top for removing solid contaminants.

Figure No. 3: Illustrates flexible mesh basket as an embodiment of the melting device (100) of the present invention.

Figure No. 4: Illustrates additional embodiment of the melting device (100) of the present invention having jacketed vessel with inlet and outlet for heating medium.

Figure No. 5: Illustrates additional embodiment of the melting device (100) of the present invention having air lock feeding system at the inlet.

Figure No. 6: Illustrates perspective view of typical pyrolysis plant with the arrangement of melting device (100) having solid discharge valve at the bottom as per present invention.

Figure No. 7: Illustrates perspective view of typical pyrolysis plant with the arrangement of melting device (100) having solid discharge valve at the top as per present invention.

DETAILED DESCRIPTION OF THE INVENTION: Disclosed herein are device, systems and methods for effective melting of plastics and waste plastics, and for providing a melted mass for a non-limiting plastic recycling processes and systems such as chemical or thermal reactor for batch or continuous reaction or process.

The terms“melter”,“device”, "reactor," "plant," "vessel," and "tank" are used herein interchangeably. The device structure can be formed of a substantially rigid material. Non-limiting examples of materials that can be used to form the device structure include stainless steel, aluminium, copper, titanium, high performance alloys, glass and combinations thereof.

In view of the present invention, an embodiment herein provides a melting device of the pyrolysis plant for providing a uniformed molten feedstock, devoid of any solid contamination like metal, stone, hard material in the pyrolysis reactor according to industrial requirement.

The present invention provides a device for melting plastic waste for feeding into a pyrolysis reactor. More preferably, the present invention provides a melting device (100) for waste plastic pyrolysis plant comprises of a jacketed agitated or fluidised vessel, an outlet for gas, an outlet for molten mass, an inlet for melting medium, stirrer, temperature sensor, and a perforated partition (vertical tubular perforated pipe or basket or channel) for segregation of foreign matter like metal and stones. The outlet for molten mass is provided with jacketed conduit and connected to pyrolysis reactor, optionally through basket fdter. The outer jacket is provided with inlet and outlet for circulation of heat transfer medium (HTM).

In a preferred embodiment, the present invention is provided with melting device for melting of waste plastics contaminated with solid materials and providing a molten plastic feedstock suitable for pyrolysis reaction, comprising of:

- a agitated or fluidised vessel having temperature controlling jacket connected to an inlet and outlet for the heat transfer medium for providing temperature control to said agitated or fluidised vessel, - a tubular perforated pipe or basket extending inside the said agitated or fluidised vessel and connected at top to an inlet for the waste plastic to be melted and an outlet at the bottom for solid particles which remained undissolved,

- an outlet to said agitated or fluidised vessel for melted plastic feedstock and operable under air lock feeding means;

-a temperature sensor probe for recording the temperature inside said agitated or fluidised vessel,

-an impeller means for providing a stirring,

-an outlet for gaseous stream;

Characterized in that the said tubular perforated pipe or basket having perforations on wall for enabling only molten plastic to flow in residence time during treatment into the agitated or fluidised vessel and entrapping a solid undissolved contaminant materials.

Wherein a tubular perforated pipe or basket is configured in vertical or in slanting position with respect to the height of said agitated or fluidised vessel and the perforations on tubular perforated pipe or basket are evenly spaced.

According to an embodiment, the present invention is improvement of simple jacketed agitated or fluidised vessel configured with a tubular perforated pipe or basket for receiving the solid waste plastic feedstock (non- shredded/shredded) inside a heated agitated or fluidised vessel comprising melting medium. The said tubular perforated pipe or basket has one or more perforations which allows to enter the hot melting medium in said tubular perforated pipe or basket helping to melt the plastic waste inside the tubular perforated pipe or basket. In an embodiment, the tubular perforated pipe(s) or basket (s) has one more perfbration(s)which allow melted mass to exit the tubular perforated pipe or basket and enter the agitated or fluidised vessel.

In a preferred embodiment, the tubular perforated pipe or basket has multiple perforations. In an embodiment, the perforations are evenly spaced. In an embodiment, the perforations size in the tubular perforated pipe or basket is uniform. In an embodiment, the perforations size in the tubular perforated pipe or basket are not uniform.

In preferred embodiment, the side wall of the perforated vertical tubular perforated pipe or basket are making a passage to melting medium to come in contact with solid waste plastic feedstock, thereby allow to melt the feedstock forming a uniform molten mass of feedstock and melting medium and allowing to pass only melted mass into agitated or fluidised vessel and restricting entry of undissolved undesired constituents. Further the bottom of perforated partition is optionally a conically tapered and closed by flush bottom valve.

According to an embodiment, the air lock feeding system is mounted on inlet of said perforated partition.

In accordance to one of the embodiments, the melting medium is selected from wax, oil, any suitable solvent for pyrolysis or mixture thereof.

In an embodiment, the present invention also provides a process wherein plastic waste is suitably mix with waste wax or oil by-product of pyrolysis plant to provide a preheated molten mass comprising of plastic material and hot medium that will save the energy required to start the pyrolysis plant and to save the thermal energy required to run the pyrolysis reaction as well.

Referring to figure no. 1 and 2, by way of example and not limiting to the scope of invention, an exemplary pyrolysis plant for pyrolysis of plastic waste for forming an oil and lubricants from waste plastic is schematically depicted in which a melting device (100) for melting of waste plastics contaminated with solid materials and providing a molten plastic feedstock suitable for pyrolysis reaction, comprising of:

- an agitated vessel ( 1 ) having a heating arrangement (2) to supply heat inside the vessel (1), - a tubular perforated (9) channel extending inside the said agitated vessel and connected at top to an inlet (10) for the waste plastic to be melted and an outlet (11) at the top or bottom for retaining solid particles which remained undissolved,

- an outlet (5) to discharge the molten plastic feedstock,

- an inlet (15) with means for dosing plastic melting medium into vessel, plastic melting medium can be selected from wax, oil, by-products of pyrolysis or other chemical reaction,

-a temperature sensor probe (7) for recording the temperature inside said agitated vessel,

-an impeller means (6) with motor for providing an agitation in vessel,

-an outlet (8) for gaseous stream evolved during heating includes chlorine, moisture etc;

Characterized in that the said perforation on channel is enabling only molten plastic to flow into the agitated vessel while entrapping a solid undissolved contaminant materials inside the tubular perforated channel. The perforations on tubular perforated channel are evenly or unevenly spaced and size of perforations are uniform or non-uniform and selected from pore size between 0.01mm to 10000 mm. Wherein a tubular perforated channel is configured in vertical or in slanting position with respect to the height of said housing.

In another embodiment, the melter (100) further comprised of a vapour outlet (7) to separate a gaseous undesired additive such as Chlorine and Oxygen gas. The said outlet is further connected to condenser or scrubber for suitable treatment and storage of said contaminants.

Further, as per embodiment of the invention, the tubular perforated channel (9) can be rigid perforated tube or mesh basket having flexible body to provide suitable bottom shape to settle solid particles. Wherein rigid pipe with bottom side outlet (11) to remove undissolved solid particles is closed by flush bottom valve (16). And in case of flexible mesh basket type tubular channel has a discharge at the top for removal of solid undissolved particles by lifting the basket outside the vessel.

According to present invention and in accordance to one of the important embodiment of present invention, the said tubular perforated pipe or basket (9) is positioned such that it form a path from the outer top side of tank (1) till the outer bottom side of tank. Wherein the inlet (10) and outlet (11) of the tubular perforated pipe or basket (9) is coupled with air lock system. The said tubular perforated pipe or basket (9) disposed in tank agitated or fluidised vessel is having perforation on the wall and size of perforations are ranging from 0.01 mm to 10000 mm, more preferably 0.01 mm to 100 mm.

In an important embodiment of the present invention and referring to figure no. 3, a flexible mesh basket rested on a supporting rod (16), wherein a tubular perforated channel shape is selected from conical, cylindrical or non- conical.

In an another embodiment of the present invention and referring to figure no. 4, vessel can be a jacket or any other arrangement to supply heat inside this vessel. The heating arrangement (2) is selected from jacket surrounding the vessel having inlet (3) and outlet (4) to circulate the heat transfer medium or electric heating coil.

Referring now to figure no. 4, an improved melter (100) for use in pyrolysis plant is schematically depicted from the front view. The melter (100) comprising of main tank agitated or fluidised vessel (1) including a jacket (2) to control the temperature of agitated or fluidised vessel. The jacket (2) further includes an inlet (3) and outlet (4) for temperature controlling medium. The melter (100) further includes an impeller (6) positioned at the centre configured with a motor and temperature sensor (7). The tank assembly (1) is portioned by positioning a tubular vertical tubular perforated pipe or basket (9) at the rear comer of agitated or fluidised vessel leaving a sufficient space for efficient stirring effect by an impeller (6). Wherein, the said vertical tubular perforated pipe or basket has one or more perforations on the wall of tubular perforated pipe or basket. The outlet (5) of melter is provided to withdraw the molten mass from the said tank assembly and configured with a temperature-controlled conduit (Jacketed) and flow controller for proper dosing of molten plastic waste in to a pyrolysis reactor.

Further, referring to figure no. 5 of the melter device (100) disclosed in present invention, wherein an inlet (10) of tubular perforated channel is configured with hopper (13) and feeding means (14) for feeding waste plastic under air lock feeding means.

In conventional melter design, the melter is generally a jacketed reactor with stirrer and temperature monitoring system. However, such simple designs have proven inadequate for separating the small undesired solid particles present in municipal or industrial waste plastic feed. Specifically, the pre -sorting and shredding of received plastic waste is the necessary step which is very tedious and ineffective as very minute particles still remain in the pockets of plastic waste. Hence, the modified melter configured with perforated partition in the embodiment shown and described in the present invention mitigate the deficiencies in the aforementioned conventional melter design.

In an embodiment, the at least one vertical channel of tubular perforated pipe or basket may be positioned along the edge of the reactor (1). In an embodiment, more than one tubular perforated pipe or basket may be positioned at spaced intervals and location away from the impeller and more preferably along the side wall of the reactor (1).

The present invention provides a method of installing a melting device (100) as substantially described in this specification the melting device (100) for waste plastic pyrolysis plant as per present invention is positioned on the pyrolysis reactor that is working between temperature 250 to 400 °C, or more, via basket filter. The pyrolysis reactor is further connected to separation assembly for separation pyrolysis products such as oil, wax and gases. More preferably, the separated wax or oil tank is connected to said melting device (100) through a jacketed conduit to recycle the wax as a melting medium for solid waste plastic feedstock.

The tubular perforated channel at the bottom is configured with a ferromagnetic material for attracting and quick settling down the metallic undissolved solid particles and an outlet of tubular channel has different variation of size and shape placed inside the agitated or fluidised vessel.

In accordance to one more embodiment, the said melting device (100) for pyrolysis plant require working temperature between 150 to 300 °C, depend upon the nature of feedstock and pyrolysis reactor temperature.

In accordance to one more embodiment, the said melting device (100) for pyrolysis plant comprises of outlet for gases such as chlorine, oxygen etc. Hence, non-limiting provision can be provided wherein the outlet may be coupled together with one or more system to dissolve/collect the by-product possibly evolved along with gases in any suitable scrubbing medium or collect pure gases for industrial purpose.

In some embodiment, multiple sensors, valves, pumps, supports, are positioned in close proximity to or in direct contact with any of the element of said device to provide necessity to said device.

A still further aspect of the present invention is directed to said melter device comprising said tubular perforated pipe or basket enabling only molten plastic mass to flow in desired residence time of treatment of melting medium and temperature in melter agitated or fluidised vessel.

Optionally there is provided with means to feed plastic waste through the inlet of the tubular perforated pipe or basket at desired flow rate and under air lock system.

The tubular perforated pipe or basket in a jacketed agitated or fluidised vessel configured to prevent the metal and hard material from entering into a pyrolysis reactor, thereby reducing the char formation in reactor. Further, the metallic contaminations separated from the bottom of perforated partition is collected periodically in a bin. The separated metals within bin can then be processed downstream by conventional techniques to produce a commercial grade metallic black that can be utilized for various known functions.

It is thus possible by way of the present invention to provide a plastic me Iter for in-situ separation of undesired additives from plastic feedstock and allowing to pass only plastic melted feedstock with reduced chlorine content in to pyrolysis reactor. The melting device according to present invention is a cheap and easy to construct. It is a round bottom type reactor with vertical pipe forming channels for flow of the solid plastic feedstock possibly contaminated with wood or metal pieces along with plastic containing higher chlorine content whereby the metallic/solid contaminants are substantially removed from the plastic feedstock and the treated plastic can be pass as a suitable feedstock in main pyrolysis reactor. Advantageously, the chlorine content in plastic feedstock can also be reduced in same melter as provided with gas outlet.

BEST METHOD TO USE THE MELTING DEVICE AS PER PRESENT INVENTION:

Referring to accompanied Figure 6 and 7, it schematically represent the entire pyrolysis plant for plastic waste recycling, it should be understood that other processes may be used to recycle the plastic waste, including without limitation, chemical decomposition or the like.

Referring to figure no. 6 and 7 by way of example and not limiting to the scope of invention, an exemplary pyrolysis plant for pyrolysis of plastic waste for forming an oil and lubricants from waste plastic is schematically depicted in which a melter (100) is used to provide the suitable feedstock into a pyrolysis reactor (103). The typical pyrolysis plant includes a melter (100) as provided in present invention, wherein unsorted plastic waste is drop into the hopper system (113) having air lock feeding system and pass to an inlet of melter vessel attached to a tubular channel. A molten wax or oil is introduced into a vessel from a inlet for melting medium through a conduit (109) and heat is applied through a jacketed portion of a melter (100). Stirring using agitator helps to transfer the hot oil or hot wax into a tubular perforated channel containing a waste plastic. It leads to melting of plastic and forming a uniform liquid mass of plastic and undissolved/ thermally stable solid contaminants already present in a waste plastic fed into a hopper. Temperature of vessel is continuously monitored by temperature sensor and once the completing of residence time in melter, the molten mass suitable for pyrolysis is discharged through an outlet at the bottom in to a temperature controlled conduit (110) connected to melter (100) outlet for transferring molten plastic feedstock suitable for pyrolysis reaction and free from solid contaminants, the said conduit is to transfer the melted feedstock into a pyrolysis reactor (103), Optionally through a basket filter (111) and flow controller (112), vapour outlets connected to series of condensers (104) and (105) that will separate the gas (108) from condensed stream (106), (107) as a wax and oil. The condensed wax partly or whole can be recirculate to melter (100) to provide a melting medium through a conduit (109). As per one of the embodiments, the outlet (102) is to collect the gaseous vapours such as chlorine and oxygen, further condensing and collecting in a tank or cylinder.

Further, the perforated channel entraps the solid undissolved contaminant and can be removed from solid outlet discharge means either from bottom valve or from top side.

Hence, the present invention provides process of operation of pyrolysis plant by providing a maintenance free and useful device for pyrolysis plant, wherein the pre-melting of waste plastic feedstock in wax recovered in same pyrolysis plant and providing a melted substantially pure mixture of plastic and wax in a reactor in semi-solid/liquid form increases the overall heat exchange capacity of the reactor and ultimately increased the productivity. It will be appreciated from the above that the melting device/system as disclosed in the present invention for thermal pyrolysis induced reaction operations as highly desired in the art, including batch and continuous process flow. Such device desirably would utilize heat recovered in pyrolysis plant as a source of heat transfer medium instead of using electric energy and reduces the cost of total pyrolysis performance as compared to the conventional systems.

ADVANTAGES OF THE PRESENT INVENTION:

-The plastic melter (100) of the present invention, due to its modular nature, allows only plastic material to form into a ready-to-add hot feedstock directly into a pyrolysis reactor without fear of loss of pyrolysis reactor performance and final product quality.

-The plastic melter (100) of the present invention, due to its structural features, that is effective in conditions where the plastic feedstock may be highly contaminated with metal, stones and other non-plastic parts.

- The plastic melter (100) of the present invention, due to its structural features, and chlorine from PVC content removable outlet, exhibits enhanced feedstock quality for pyrolysis and reduced catalyst deactivation.

-The melting device (100) of the present invention is of sustainable design in that it can support long-term running of pyrolysis plant, and does not require maintenance of pyrolysis plant due to restricted entry of hard metal, stones or non-plastic particles in pyrolysis reaction zone.

-The pre-treatment process wherein plastic waste is suitably mix with waste wax or oil by-product of pyrolysis plant to provide a preheated molten mass comprising of plastic material and hot medium that will save the energy required to start the pyrolysis plant and to save the thermal energy required to run the pyrolysis reaction as well.

Claims

CLAIMS laim;

1. A melting device (100) for melting of waste plastics contaminated with solid materials and for providing a molten plastic feedstock suitable for pyrolysis reaction, comprising of:

- an agitated vessel (1) having a heating arrangement (2) to supply heat inside the vessel (1),

- a tubular perforated channel (9) extending inside the said agitated vessel and connected at top to an inlet (10) to drop the waste plastic to be melted and an outlet (11) discharging a solid particles which remained undissolved,

- an outlet (5) to discharge the molten plastic feedstock suitable for pyrolysis reaction,

- an inlet (15) with means for dosing plastic melting medium into vessel (1),

-a temperature sensor probe (7) for recording the temperature inside agitated vessel (1),

-an impeller (6) with motor for providing an agitation in vessel,

-an outlet (8) for gaseous stream;

Characterized in that the said perforations on channel (9) is entrapping a solid undissolved contaminant inside the tubular channel and enabling only molten plastic waste that is free from solid contaminants to flow into the agitated vessel (1) when comes in contact with melting medium that resulting into providing a molten plastic feedstock suitable for pyrolysis reaction.

2. The melting device (100) as claimed in claim 1, wherein a tubular perforated channel (9) is configured in vertical or in slanting position with respect to the height of said housing.

3. The melting device (100) as claimed in claim 1, wherein a tubular perforated channel (9) is selected from rigid pipe or flexible mesh basket rested on a supporting rod (16).

4. The melting device (100) as claimed in claim 1, wherein the heating arrangement (2) is selected from jacket surrounding the vessel (1) having inlet

(3) and outlet (4) to circulate the heat transfer medium or electrically heating coil.

5. The melting device (100) as claimed in claim 1, wherein a tubular perforated channel (9) shape is selected from conical, cylindrical or non-conical.

6. The melting device (100) as claimed in claim 1, wherein the perforations on tubular perforated channel are evenly or unevenly spaced.

7. The melting device (100) as claimed in claim 1, wherein perforations size on the tubular perforated channel are uniform selected from pore size between 0.01mm to 10000 mm.

8. The melting device (100) as claimed in claim 1, wherein perforations size on the tubular perforated pipe or basket are non-uniform selected from pore size between 0.01mm to 10000 mm.

9. The melting device (100) as claimed in claim 1, wherein an inlet (10) of tubular perforated channel (9) is configured with hopper (13) and feeding means (14) for feeding waste plastic under air lock feeding means.

10. The melting device (100) as claimed in claim 1, wherein the bottom side outlet ( 11) of perforated tubular channel to remove undissolved solid particles is closed by flush bottom valve (16).

11. The melting device (100) as claimed in claim 3, wherein the flexible mesh basket type tubular channel (9) has a discharge outlet (11) at the top for removal of solid undissolved particles by lifting the basket outside the vessel.

12. The melting device (100) as claimed in claim 1, wherein bottom side of tubular perforated channel is configured with a ferromagnetic material for attracting and quick settling down the metallic undissolved solid particles.

13. The melting device (100) as claimed in claim 1, wherein an outlet of tubular channel has different variation of size and shape placed inside the agitated or fluidised vessel.