Field of the invention:
The present invention relates to a system for pyrolysis in indirect rotary kiln includes a novel feeding system and the sealing system. The pyrolysis system of the present invention is invented for the thermal decomposition of scrap tires, plastic and rubber waste, electronic scrap goods & waste hydrocarbon.

State of the art:
The disposal of scrap tyres, plastic and rubber waste, electronic scrap goods and waste hydrocarbon causes problem for environment. Disposal of theses goods has been done in landfill site or by open dumping. Recycling of such material is difficult, however, pyrolysis technology is unique and known to the ordinary person skilled in the art where such waste material is recycled to generate energy or fuels.
Pyrolysis is a thermal process for breaking down hydrocarbon materials in the absence of oxygen into smaller constituent materials, including carbon and hydrocarbon compounds with a wide range of molecular weights and gases. Pyrolysis typically occurs under pressure and at operating temperatures above 400o C. When feedstock consists of organic polymers, pyrolysis causes the polymer backbone to decompose and the products can include carbon char and condensable and non-condensable gases.
During tire pyrolysis, chemical bonds within the rubber compounds are broken down, creating a mixture of organic compounds and non-condensable gases. Carbon black, present as a major component in the tire polymer matrix, is freed. Other inorganic compounds, such as silicon dioxide, zinc oxide and aluminum oxide, present within the tire are also freed from the polymer matrix. Organic compounds within the matrix, consisting of larger carbon chains (C6 and larger), sublime to a gaseous state at normal operating temperatures and include a mixture of aromatic, aliphatic and olefinic hydrocarbons. Non-condensable gases such as methane, ethane, propane, hydrogen, carbon monoxide and hydrogen sulfide are also formed during pyrolysis. Additional carbon black, is also formed when carbon is split off from the polymeric chains and is carbonized. The end products of a tire pyrolysis process typically include carbon black, pyrolysis oil, non-condensable gases, and inorganic ash.
In known pyrolysis processes using an indirectly heated rotary kiln, the material to be processed is passed into one end of the kiln. The kiln is usually set on rollers and is at a slight incline to the horizontal. The feed material is fed into higher end of the kiln. It passes through the rotating drum of the kiln and the non-volatile portion passes out at the lower end. Heat generated in a furnace surrounding the kiln provides the energy required for the pyrolysis. The kiln has a steel wall which is heated to a predetermined temperature and the heat passes by conduction through the steelwork and hence into the material to be pyrolysed.
US 4,405,137 describes a flexible rotary seal which uses discrete metal leaves formed from resilient sheet metal which are overlapped and secured to the hood at one end and have the other end secured to a wear liner. The metal leaves are bent and stressed so that the wear liner is biased into continuous engagement with the rotary kiln, and a cable assists in holding the wear liner against the rotary kiln.
US 4,405,137 have proven metal leaf rotary seals of the type to efficiently seal rotary kilns, small gaps or spaces may develop between the overlapping metal leaves in operation, particularly if the wear liner wears unevenly. Uneven wear may result if the kiln rotates irregularly or if thermal expansion causes the kiln to develop an irregular shape. It should be noted that for large kilns of several hundred feet longitudinal thermal expansion may be around one foot.
Published US patent application US 20090277090 relates to reactors such as rotary kilns for the gasification of mixed size of solid carbonaceous materials such as biomass and solid wastes in a tumbling state and particularly to the gas distribution port for introducing gases such as air, oxygen, and steam to the interior of the rotary kiln wherein this gas distributor assures gas solid mixing inside the reactor to promote gas solid reaction.
GB 1240238 discloses apparatus for sealing the joint between a stationary part and a rotary part of a kiln. With this sealing device the rotary kiln atmosphere lies adjacent to the seal on the kiln side. The seal is therefore exposed to the atmosphere inside the kiln, which contains dust and/or corrosive materials that could damage the seal and contribute to a reduction in efficiency. This could cause gases to escape from inside the kiln to the environment.
Most conventional rotary kilns have mechanical sealing devices at both the inlet and outlet ends to prevent air ingress into the kiln and blowing out of gases from the kiln. However, existing seals are relatively complex and expensive to produce and it is difficult to maintain a permanent seal of the required high standard.
In these pyrolysis processes it is necessary to keep air out of the vessel, otherwise the pyrolysis gases could explode. Moreover, the pyrolysis gases produced should not be allowed to escape from the vessel and cause pollution to the atmosphere.
To overcome the drawbacks occur with the existing pyrolysis processes, we have develop rotary kiln with oil deeping airtight feeding system, conveyor outlet for carbon black, condensation system for conversion of condensable gases and firing of incondensable gases through burner.
Summary of the invention:
The main object of the present invention is to provide a pyrolysis system incorporated to the rotary kiln wherein feeding of raw material is carried out with novel idea. Novel feeding system is designed with the help of inclined conveyer, where feeding material passes through oil deeping tank to seal the air passage in the process.
The other object of the present invention is to provide pyrolysis system wherein rotary kiln is sealed at one end of feed material supply and at gas discharge end of rotary kiln to avoid oxygen interference in the process.
Another object of the invention is to provide a novel sealing system for pyrolysis process in rotary kiln comprises piston ring with zigzag path filled with high temperature grease in between rotating and stationary parts of the kiln.
Another object of the invention is to provide a pyrolysis process for the scrap material combusted and resulting in oil used as fuel to replace furnace oil. The pyrolysis process produce carbon black as by product which can directly used as solid fuel.
Another object of the invention is to provide a cost efficient, leak free, highly efficient pyrolysis process using a novel feeding system and sealing system.
Detailed description of the drawings:
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, of which:
FIG. 1 shows a schematic view of a rotary kiln system in accordance with an embodiment of the present invention.
Detail description of the invention:
A system for pyrolysis carried out in a rotary kiln involves novel feeding system and sealing system.
The Rotary kiln is a cylindrical vessel, inclined slightly to the horizontal, which is rotated slowly about its axis. The material to be processed is fed into the upper end of the cylinder. As the kiln rotates, material gradually moves down towards the lower end. The Kiln is heated indirectly by initially conventional liquid fuel/tire oil later on it is replaced by non-condensable gas, which is self sufficient for process. Rotary kiln is made from steel plate, 15-20 mm thick, welded to form a cylinder which is 8 m in length and up to 0.9 m in diameter.
A seal is essential at each end to prevent ambient air from entering the pyrolysis process. A leaky seal may reduce efficiency, create unsafe and unstable conditions. The output of pyrolysis of these scraps produces four different products, condensable gases which will condensed to pyrolysis oil, it is clear fuel, replace LDO, non-condensable gases which will used directly as heat energy for self process & metal. The gas produced in pyrolysis process are of high calorific value and sufficient to provide the energy requirement for the pyrolysis process. The carbon black produced as by product of pyrolysis can be used directly as solid fuel, as substitute for raw material for pigment, in rubber industries and chemical industries.
The pyrolysis process performed herein is continuous. The feeding capacity of the pyrolysis plant is 700-1200kg/hr. Fuel properties of the oil produced from the present pyrolysis process are compared with those of petroleum-derived fuel products by means of standard ASTM or IP methods.
The present pyrolysis system is invented for the thermal decomposition of scrap tires, plastic and rubber waste, electronic scrap goods & waste hydrocarbon. Scrap tire pieces are cleaned to remove dirt and metal particles. Produced fractions are recycled using shedder, from there continuously fed 50mmx50mm size to the rotary kiln. In the rotary kiln, the material is heated for about 300-500°C and split into gas and solids. In the discharge casing of the rotary tube, the solids are separated from the gas. The solids (carbon black) in the powdery form are discharged with a screw conveyor from the rotary kiln and cooled to about 60°C.The Pyrolysis vapour gas is discharged from the upper part of the discharge casing and passes through specially designed condenser to condense to pyrolysis oil which is very less sulfur content, <0.5%, it is very good fuel and almost equivalent to LDO, whereas Furnace oil has 3-4% sulfur content. Combustion of pyrolysis oil creates almost negligible IHGE as compare to very high with combustion of Furnace oil. The condensed pyrolysis oil is pumped into a storage tank. The non-condensable portion of the gas is pressurized and fed to the burners for combustion chamber in order to produce the process heat to heat the rotary kiln indirectly.
In the said present invention Rotary kiln implicated is a cylindrical vessel, inclined slightly to the horizontal, rotating slowly (2 to 4 RPM) about its axis, the speed of which controlled according to need of the process. The kiln is heated indirectly by the initially conventional liquid fuel/tire oil later on it is replaced by non-condensable gas, which is self sufficient for process. Rotary kiln is made from steel plate, 15-20 mm thick, welded to form a cylinder which is 8 m in length and up to 0.9 m in diameter. A seal is essential at each end to prevent ambient air from entering the process. Air leakage can have varying effects on different process. A leaky seal may reduce efficiency, create unsafe and unstable conditions. The feeding of small size rubber pieces (approx. 50 to 100 mm) is carried out with help of new invented feeding system at 700 kg to 1200 kg/hr and retention time is 20 to 30 minutes for pyrolysis of scrap tire. This rotary kiln is covered by hexagonal shape prepared from mild steel plate material through which the fuel is burn with the help of burners and indirect heating is performed.
In a pyrolysis process no oxygen should entered anywhere in process otherwise it causes explosion. Therefore, feeding of raw material (scrap tires, Plastic and Rubber waste, electronic scrap goods & waste hydrocarbon) is carried with a new feeding system with help of inclined conveyer where feed material passes through oil deeping tank which work as air sealing and used highly sophisticated electronic controlled devices to monitor precisely. Novel feeding system is unique and leakage free. In the said novel feeding system hopper is filled with oil, and not allowed to enter air/oxygen. The hopper is connected with inclined conveyor, which carries the feeding material up to rotary kiln. The speed of conveyor is fully controlled; depend upon the requirement of plant. In the said system the feeding capacity is 700-1200 kg/Hr.
In the pyrolysis process of the present invention rotary kiln is sealed at beginning of feed material supply and at gas discharge end. The sealing is essential to avoid entry of oxygen in this pyrolysis process. The said sealing system comprises of piston ring with zigzag path and it’s filled with high temperature grease in between rotating and stationary parts along with conventional sealing system to overcome any environmental issue and safety hazards. Sealing system leads to block the leakage of condensable gases, which leads to increase output of oil and block the leakage of non-condensable gases, which helped to improve the heating of rotary kiln. Using the said sealing system in the pyrolysis process improves the efficiency and make plant environment friendly.
The pyrolysis process in a rotary kiln is to be performed under controlled temperature, wherein temperature is measured at various locations in the rotating furnace or kiln. In the present invention the pyrolysis system incorporated wherein furnace temperature need to be maintained upto 8500-10000 C. To attain the temperature requirement we have used thermocouple which measures precisely the temperatures all through the process in a rotary kiln.
We put the thermocouples in a drum to measure the temperature of kiln/furnace surface and raw material inside the kiln. Wires are connected to temperature controlling panel which shows the record of the temperature maintained throughout the pyrolysis process in a rotary kiln.

We Claim:
1. A system incorporated in a rotary kiln for pyrolysis involve novel feeding system and sealing system wherein;
- the rotary kiln is a cylindrical vessel, inclined slightly to the horizontal, which is rotated slowly about its axis, the scrap material (raw material) to be processed is feeding into the upper end of the cylinder and as the kiln rotates, material gradually moving down towards the lower end, heated indirectly by initially conventional liquid fuel/tire oil later on it is replaced by non-condensable gas, which is self sufficient for process,
- feeding raw material passing through oil dipping hopper under airtight condition to the one end of rotary kiln with the help of inclined conveyor,
- sealing one end of kiln where feeding material is supplied provided piston ring with zigzag path filled with high temperature grease and the other gas discharging end to prevent ambient air from entering the process.
2. A system for pyrolysis carried out in a rotary kiln as claimed in claim 1 wherein, rotary kiln is cylindrical vessel made from 15-20 mm thick steel plate, further welded to form a cylinder shape of 8 m in length and up to 0.9 m in diameter.
3. The pyrolysis process as claimed in claim 1 is a continuous process wherein feeding capacity of the plant is 700-1200 kg/hr.
4. The pyrolysis process as claimed in claim 1 wherein, scrap material includes scrap tires, plastic and rubber waste, electronic scrap goods & waste hydrocarbon pyrolysed in a rotary kiln to produce condensable gases, non-condensable gases and carbon black.
5. The pyrolysis process as claimed in claim 1 to 4 wherein, the process includes cleaning scrap tire pieces to remove dirt and metal particles, recycling produced fractions using shedder, from there continuously feeding 50mmx50mm size fractions to the rotary kiln, heating the material for about 300-500°C, splitting into gas and solids, separating solids from gas in the discharge casing of the rotary tube, the solids (carbon black) in the powdery form are discharged with a screw conveyor from the rotary kiln and cooled to about 60°C, pyrolysis vapour gas is discharged from the upper part of the discharge casing and passes through condenser, condensed pyrolysis oil is pumped into a storage tank, non-condensable portion of the gas is pressurized and fed to the burners for combustion chamber to produce heat to heat the rotary kiln indirectly.
6. The pyrolysis process as claimed in claim 1 wherein, furnace temperature is maintained upto 8500-10000 C, which is measured by using thermocouples.
7. A system for pyrolysis as claimed in claim 1 to 6 wherein providing airtight seal at each end of rotary kiln to prevent ambient air from entering the process and to avoid any leakage of gases from the kiln to reduce chances of explosion.
8. A system for pyrolysis incorporated in a rotary kiln as claimed in claims 1 to 7 as herein described with foregoing description and drawing.

Dated this 19th Day of September 2011

______________________________
Ms. Dipal Rajesh Dhabhai
Registered Patent Agent
For and on behalf of the Applicant

ABSTRACT
The present invention relates to a pyrolysis system incorporated in a rotary kiln with oil deeping airtight feeding system, conveyor outlet, condensation system for conversion of condensable gases and firing of incondensable gases through burner. Rotary kiln is indirectly heated by initially conventional liquid fuel/tire oil later on it is replaced by non-condensable gas, which is self sufficient for process. Scrap tires, plastic and rubber waste, electronic scrap goods and waste hydrocarbon get thermally decomposed due to temperature and converted to carbon black and gases. Further gases are condensed by using water condenser and convert to liquid fuel and incondensable gases used as recycled for heating rotary kiln through burner. A novel sealing system is involved in the said pyrolysis process, which is provided piston ring with Zigzag path filled with high temperature grease in between rotating and stationary parts.