Title of Invention

"IMPROVED ECO-FRIENDLY RECYCLING PROCESS OF POST CONSUMER WASTE PLASTICS AND DEVICE THEREOF

Abstract

The present invention relates to an improved eco-friendly / green recycling process of post-consumer waste plastics and a device thereof. The main goal for developing eco-friendly / green recycling of post-consumer waste plastics is to design an extruder (1), which would have "Zero Significant Adverse Environmental Impact". This has been achieved by assigning right collection method, right equipment, heat sealing and right temperature for the processes and trapping all the emission in pollution control gadget (12, 13) and treating the pollutants to produce by-products for commercial utilisation. The present invention identifies pollutants generated and reduces the level of emission to air to a minimum from the process thereby reducing energy consumption with better product quality. Collection & segregation methods for the recycling process of post-consumer waste plastics have been delineated in the present invention. The extrusion process has been re-engineered to reduce and control the emission generated during the post-consumer waste plastics recycling.

Full Text

1 FIELD OF INVENTION The present invention relates to plastic waste management reengineering of the recycling process of packing plastic, more particularly, to an improved recycling process of waste plastic and here it is named as eco-friendly / green recycling process of post-consumer waste plastics. The main goal for developing eco-friendly / green recycling of post-consumer waste plastics is to design an extruder, which would have "Zero Significant Adverse Environmental Impact" This has been achieved by assigning right collection method, right equipment, heat sealing and right temperature for the processes and trapping all the emission in pollution control gadget and treating the pollutants to produce byproducts for commercial utilisation. "Greening" the recycling process means that the pollutants generated from the extrusion process is lesser and is controlled in such a manner so that the gaseous emission does not release into the atmosphere 2. BACKGROUND OF THE INVENTION Description of the Related Art The world's annual consumption of plastic materials has increased from around 5 million tones in the 1950s to nearly 100 million tones today. Packaging represents the largest single sector of plastics use in the world The sector accounts for nearly 35% of plastics consumption and plastic is the material of choice in nearly half of all packaged goods Further uses are in building/construction, electrical and electronics industry, the automotive/ transport and the furniture / house wares sectors. Other sectors consuming smaller proportions of plastics are agriculture/ horticulture, toys / leisure /sports, medical and mechanical engineering and footwear manufacture. Since the first synthetic polymers were created around a century ago, and particularly since the 1950s, the use of plastic worldwide has increased enormously Plastics are an integral part of our present lifestyle and its usage in wide spectrum of applications This exponential use and growth of plastics has also led to waste generation The use of plastics in India began in the 60s, when a two-pronged approach for recycling was adopted In the initial stages of recycling, it was the cottage industry, which utilise scrap cellulose acetate film and acrylic scrap for bangle making The amount of post-consumer waste plastics generated is enormous. These wastes are creating problems in the society Plastics are easily recyclable But the recycling processes of packaging plastics adopted by recyclers create environmental problems The recycling process involves selection, sorting, cleaning & washing, shredding or grinding, 2 agglomeration, extrusion, cooling and cutting or palletizing. All these sub-processes generate environmental pollution. Plastics per se are not harmful or chemically active. They are inert or neutral in the environment However they pose a threat to the environment essentially due to the lack of an efficient collection and disposal system. Plastics are most commonly used in the form of carry bags and as packaging material both of which are non-biodegradable Ideally speaking, after use polythene carry bags ought to be incinerated, buried in landfills or recycled However in the absence of a proper collection and disposal system, they are usually strewn around in our surroundings or accumulate in garbage and heaps. It is this accumulation of plastic bags, which are non-biodegradable, which poses a senous hazard to the environment Animals specially cattle after consuming them often choke and die. These polybags are deep enough to act as receptors of water sufficient enough for mosquito breeding According to environmentalists, they float on the rivers close to the cities, settle on their beds, and cutting off oxygen to aquatic life They clog sewage pipes and prevent methane gas from evaporating which often causes explosions They block off air supply to anything they rest on Since they are non-biodegradable they cannot be destroyed and on burning emit toxic gases They also affect soil fertility and water percolation in the ground preventing the growth of plants. Thus even though plastic bags are an efficient and economical packing material their non-biodegradable nature and absence of a safe mechanism for their disposal makes them an environmentalists nightmare In India no legislation is available on handling and processing of post-consumer waste plastics This is required that legislation is enacted on the subject in India to organize the sector in a disciplined manner. In European Union, the Legislation, which is particularly relevant to plastics, is the 1994 European Union Directive on Packaging and Packaging Waste 94/62/EC (the Packaging Directive), which aimed to establish producer responsibility for packaging waste. The directive was implemented in the UK through the Producer Responsibility Obligations (Packaging Waste) Regulations 1997 and the Packaging (Essential Requirements) Regulations 1998. The former sets targets for the recovery and recycling of packaging wastes, including plastics packaging waste The EU is currently revising these targets The UK government has recently published the national packaging recycling and recovery targets for 2004 and beyond. These require 21 5% of plastics waste to be recycled by 2004, rising to 23.5% by 2008 3 The term recycling defines the recovery and reprocessing of waste materials for use in new products. The basic phases in recycling are the collection of waste materials, their processing of manufacture into new products, and the purchase of those products, which may men themselves be recycled Typical materials that are recycled include iron and steel scrap, aluminum cans, glass bottles, paper, wood, and plastics. The materials reused in recycling serve as substitutes for raw materials obtained from such increasingly scarce natural resources as petroleum, natural gas, coal, mineral ores and trees. Recycling can help reduce the quantities of solid waste deposited in landfills, which have become increasingly expensive. Recycling also reduces air, water, and land pollution resulting from waste disposal In general, post-consumer waste plastics recycling has three phases • material recycling to recycle plastics to plastic materials, • chemical recycling to chemically dissolve the plastics back to the raw material (monomer), and • thermal recycling to utilize plastics as a heat source. Among these methods, material recycling and investigation of technical methods for reusing post-consumer waste plastics for packaging and other purposes as well as collected plastics of known origin have been focused in the present invention Plastic waste management reengineering of the recycling process of packing plastic, and more particularly, the recycling process of post-consumer waste plastics heretofore devised and utilized are known to consist basically of familiar and expected processes, notwithstanding the myriad of processes encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements. Existing recycling process comprise the following steps of collection, selection, segregation and processing of post-consumer waste plastics a) Collection Rag pickers collect waste plastics from here and there and segregate from municipal solid wastes These are very hazardous and unhygienic. b) Selection The recyclers / pre-processors have to select the waste / scrap plastics which are suitable for recycling / reprocessing as per the types All medical plastics wastes and containers, used for packaging of toxic contents, such as pesticides, insecticides, should be segregated separately and put to appropriate incineration to recover energy In practice this may not be always made possible 4 c) Segregation Segregation shall be done in accordance wiih 4 1.2 of IS 14535 following by the symbol marked on the product, which is taken up for recycling. This marking wall not only facilitate segregation but will also guide customer on the buying correct usage of the end product Of course this is very difficult to follow in case of waste plastics because the marks in most of the cases disappear or not visible d) Processing The segregated plastics waste/ scrap irrespective of the source of origin and type / form shall be subjected to size reduction, cleaning from dust/dirt and washing (if applicable) with water / detergent, etc. To prevent pollution, appropriate measures have to be taken to dispose of the effluent generated as a result of washing of the waste, as per norms under pollution control Act, and only thereafter be put to recycling/ reprocessing The cleaned and washed material as obtained may be blended with additives, processing aids, pigments, etc, as the case may be, and finally granulated by using appropriate screen mesh for filtration of contaminants and impurities In the present invention efforts have been made to avoid downgrading the quality and performance of end products using recycled materials by proper collection method and an eco-friendly recycling process of post-consumer waste plastics through extrusion Known prior art recycling process of waste plastic includes WO9420590, JP2004090599; JP2004074585, JP2002121318; and US2002125600 There are also other existing prior arts related to the field of present invention. But the above prior arts are chosen to encompass the broad area of the field of the present invention and are sufficient to assess the scopes and advantages of the present inventioa WO9420590 dated 1994-09-15 to Guffey, Univ Wyoming Research Corp and Barbour, and US 5,753,086 dated 1998-05-19 to Guffey and Barbour delineate a process for recycling or decomposing waste plastic where such waste plastic is decomposed in a diluent such as hot oil through actions involving free radical precursor, such as polyvinyl chloride or polyurethane. The said process is achieved at low temperature The thermal decomposition (or pyrolysis) reaction is for about 1 hour at 375° C and usable products, such as distillate, coke, and oil are recovered. Additionally the diluent may be recycled within the process JP2004090599 dated 2004-03-25 to Kamei Takeshi provides a method for recycling processing of waste plastics capable of all of thermal recycling, chemical recycling, and 5 material recycling. The process involves sorting by each type of plastic, storing the said plastics in spaces of offices until a collection trader collects them. Next, a collecting process according to the type of plastic is performed by a collecting and conveying agent The collecting agent travels around the respective companies, collects the waste plastics sorted for each type of plastic, and conveys them to an intermediate disposal agent Next, a classification process is performed by the intermediate disposal agent The camed-in waste plastics are classified to recycling adaptable items and recycling unadaptable items, further, recycling types of the recycling adaptable items are discriminated Next, a cleaning process is performed to the recycling adaptable items, further, a drying process is performed The plastics after drying are finally transferred to each recycling routes (thermal, chemical, and material). A method and system for managing recycling of plastic product has been disclosed in JP2004074585 dated 2004-03-11 to JFE Steel KK to provide a method and a system for managing the recycling of plastic products, which can greatly enhance the rate of the recovery of the plastic products for re-recycling, which enable the recovered plastic products to immediately serve for materials for re-recycled products, without the need for cumbersome treatment such as the analysis and sorting of the recovered plastic products, which thus enable an increase in the working efficiency of the re-recycling and a reduction in cost, and which can greatly contribute to the promotion of the recycling of waste plastics and environmental improvement The system defined in that Patent includes a panel for a concrete form is manufactured from the waste plastics and shipped In the shipment of the panel, information on the manufacture and shipment of the panel is pre-registered in a database at each construction site After the use of the panel, the panel is recovered at each construction site, and the recovered plastic products are treated for the re-recycling according to the manufacturing information which is pre-registered in the database JP2002121318 dated 2002-04-23 to Ishikawajima Hanma Heavy Ind Co Ltd describes method and apparatus for chemical recycling of waste plastic The aim of this Patent is to effectively recover an olefin gas, hydrogen, and BTX from a waste plastic. This method comprises a pretreatment step for separating a waste plastic into a polyolefin plastic and other plastics, a thermal decomposition step for thermally decomposing the polyolefin plastic, a catalytic decomposition step wherein 2-4C olefins are formed from a thermal decomposition gas, generated during thermal decomposition, by the action of a boron-containing silicate catalyst of a first catalytic decomposition section and BTX and hydrogen are formed by the action of a gallium-containing silicate catalyst of a second catalytic decomposition section; a high-boiling-point component separation step for separating a high-boiling-point component from a gas coming out of previous step; and a gas-liquid separation step wherein the gas freed of the high-boiling-point component is 6 cooled to be separated into a gas phase mainly comprising a 2-4C olefin gas and hydrogen and a liquid phase mainly comprising BTX. A plastic recycling system and a process utilizing the said system, including a first granulator for reducing plastic waste to a first particle size has been narrated in US2002125600 dated 2002-09-12 to Home David. This system also includes a second granulator for reducing plastic waste to a second particle size A frictional melting structure is also provided which melts the first particles and the second particles via use of a rotating plate All the above pnor art attempts at describing plastic waste management reengineenng of the recycling process of packing plastic have made the process and the system utilising the processes cumbersome and complex. Recycling can often be a hazardous process, both m terms of worker safety and the pollutants dispersed into environment during the process In case of packaging plastics, waste must be minimized at the users end. Just because the material can be recycled, does not mean that it must be used without control The used plastics should be disposed in organized manner to avoid mix up and throwing here and there causing different types of social and environmental problems. In the present invention, eco-friendly / green recycling process of post-consumer waste plastics, followings are the advantages over the existing processes in the recycling units 1) The post consumer waste plastics are segregated by the user in a separate bin with a mark / suitable coding system, the same are collected by the municipal personnel in a specially designed two-compartment-cart having one compartment for plastics wastes and the other for municipal solid wastes. The plastics waste are placed in a separate collection bins at municipal solid waste collection center where from the recyclers or their representatives collect / purchase post-consumer plastics waste with lesser contamination to be used in plastics recycling extrusion or other processes. This reduces potential contamination of post-consumer plastics wastes 2) In the re-engineered machine the ratio of length & diameter, i e. L/D ratio has been kept at least at 28 1, the screw diameter being at least 50mm, the screw effective length comes to at least 1,400mm, which ensure adequate length in the compression zone for processing polymer, having wide melting range. 7 3) In the re-engineered machine, the speed variation is infinitely step less within a certain range, 0 to 1400 rpm, which ensure variable discharge rate of the molten plastic material 4) For achieving maximum delivery of granules by the feed section, a relatively deep channel in the screw is provided in the feeding section. However for compacting of the material, the root diameter goes on increasing so that less space (or volume) is available to the advancing material In other word, the channel depth is shallow in the compression zone compared to the feeding zone and the compression ratio is also satisfactory (higher than 1.5.1). Accurate control of temperatures by thermocouple in different zones is maintained allowing proper residence time for each operation. This is a distinct merit of the new machine 5) A sufficiently large pulsation free reproducible and thermally and physically melt stream is maintained to feed the die. This prevents freezing of plastic material in the die/die head. Also the melt being fed from the extruder finds sufficient residence time in the die to achieve relaxation of stresses and equalization of temperature 6) All the out let beyond the die/ die head, the extruded materials come out associated with emission of different gases to air. The pollution gadget takes out nearly 95% of the emitted gas from the outlet and its surroundings. This helps in making the recycling process and its surroundings atmosphere with nearly pollution free for which the recycling process would be responsible 7) Different chemicals treat the emitted gases. Different by products are produced The released gas from the pollution treatment device is pollution free and can be directly released into atmosphere This recycling process is a pollution free process The by products may be used or sold. By the treatment, the gaseous pollutants turned into salable by products with no effluents 8) Noise of the machine is kept as low as possible. The measured values are within 40 - 55 db 9) With the help of temperature controller, the temperature at each of the feed, compression and metering zone may be kept constant as desired for specific materials For preventing dissipation of heal, effective insulation with optimal insulation thickness is provided along with cover on the barrel. This helps in reduction in heat loss from the process. This saves cost and energy over the existing processes The cover on the barrel provides safety and helps in arresting temperature rise in the atmosphere in the vicinity of the machine 8 10)The operator & other personnel working in the process would be motivated to work in the pollution free atmosphere. As a result health hazard for operating personnel is lesser 11) Legislative requirements (State Pollution Control Board & Central Pollution Control Board) would easily be complied & surpassed. 12) Over and above the adverse environmental impacts from the reengineered recycling process are lesser In general this improved eco-friendly / green recycling process of post-consumer waste plastics offers pollution free process, savings in cost and energy, compliance with environmental legislative requirements and motivation for operating personnel to work with lesser occupational health hazards. In these respects, the improved eco-friendly / green recycling process of post-consumer waste plastics, according to the present invention, substantially departs from the conventional concepts of the prior art, and in so doing provides a process primarily developed for the purpose of recycling plastics. The green recycling process of waste plastic is inexpensive, easy to follow and maintenance of the apparatus is also easy 3. SUMMARY OF THE PRESENT INVENTION Accordingly, the present invention is directed to an improved eco-friendly / green recycling process of post-consumer waste plastics that substantially obviates one or more of the problems due to limitations and disadvantages of the related art It is, therefore, an object of the present invention to identify the pollutants generated during the improved eco-friendly / green recycling process of post-consumer waste plashes It is another object of the present invention to reduce the level of emission to air to a minimum from the process thereby reducing energy consumption with better product quality It is a further object of the present invention to provide collection & segregation methods of post consumer plastics for the recycling process of post-consumer waste plastics. 9 It is another further object of the present invention to provide a device for the improved eco-friendly recycling process of post-consumer waste plastics to carry out the said process Still another further object of the present invention JS to reengineer the plastic recycling process, in particular, the extrusion process, of packaging plastics to reduce and control the emission generated during the post-consumer waste plastics recycling Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present mventioa The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in description and claims hereof as well as appended drawings. To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the improved eco-friendly / green recycling process of post-consumer waste plastics having two major phases, the first phase being the process of collection and segregation of raw materials, i e, post-consumer plastics wastes, from user and keeping at proper place/ bins, cutting, cleaning and pulping, and the second phase being extrusion and pelletisation of the said waste plastic products characterised in that the said process has the following steps to reduce and control the emission generated during the said waste plastic recycling process: identification of pollutants generated during recycling process of the said post consumer waste plashes, reduction of the level of emission to air to a minimum from recycling process thereby reducing energy consumption with better product quality; and reengmeering extrusion process to reduce and control the emission generated during the said post-consumer waste plastics recycling. The improved eco-friendly recycling process of post-consumer waste plastics wherein potential contamination of the said post-consumer waste plastics are reduced during the said collection and segregation process, the said collection and segregation process involves segregation of the post-consumer waste plastics by the user in a separate bin with a mark / suitable coding system; collection of the said post-consumer waste plastics by municipal personnel in a specially designed two-compartment-cart having one compartment for plastics wastes and the other for municipal solid wastes; placing of the said post-consumer waste plastics in a separate collection bins at municipal solid waste collection center where from the recyclers or their representatives collect / 10 purchase the said post-consumer waste plastics with lesser contamination to be used in plastics recycling extrusion or other processes. The improved eco-friendly recycling process of post-consumer waste plastics wherein for the said reduction of the level of emission to air, post-consumer waste plastics are converted in the form of pulp like shape which act as raw material for extrusion process by agglomerator, or some time in an unnamed low temperature heating arrangement. The improved eco-friendly recycling process of post-consumer waste plastics wherein the said reengineenng process passes through the steps of: extrusion and pelletizauon performed by a barrel and screw type extrusion machine with band electric heater; supplying power to the said extrusion machine from a motor and feeding the screw barrel through a gearbox mounted on the said extrusion machine; heating an electric band heater through some electrical power source, feeding the said crushed / pulped / shredded raw material through hopper of the said extrusion machine, and palletizing the wire shape plastics resulted in from the said extrusion machine to get plastic granules The improved eco-friendly recycling process of post-consumer waste plastics wherein the process reduces environmental pollution level having the steps of controlling the temperature in different zones of the extruder and keeping as minimum as possible maintaining the quality of product; sucking the released gases from the die head into the pollution control gadget without allowing pollutants to be released into atmosphere and also through the pollution treatment device, releasing port for residual gases to atmosphere; and producing usable byproducts, passing these gases through intermediate environmental parameter monitoring gadget consisting of a set of impingers, vacuum pump and pipeline with valves, to know the level of pollution The improved eco-friendly recycling process of post-consumer waste plastics wherein the said residual gases, viz., SO2, HCL gas and HCHO, emitted during the processes, being reduced by 80% to BDL in the green recycling process, are passed through a set of impingers containing 50ml of each of (a) 3% H2O2 solution that absorbs SO2, (b) 0 001 M NaOH Solution that absorbs HC1 and (c) doubled distilled water that absorbs HCHO 11 The improved eco-friendly recycling process of post-consumer waste plastics wherein the outlet of the said impinger is connected to a rotameter where airflow rate is maintained at 3 litres per minute The improved eco-friendly recycling process of waste plastic wherein an ID fan connected to the said containers of chemicals discharges the said air, almost free from pollutant residual gases, to atmosphere The improved eco-friendly recycling process of post-consumer waste plastics having a recycling plant including at least an electric power system, a control panel, a pre-heater, a gear box and motor wherein the said reengineering process includes an extruder, a hopper of the said extruder, an electrical heating system having heating means of the said extruder, insulation and cover of the said extruder, a screw and barrel of the said extruder, a die and die head of the said extruder, a hood & frame, a water tank and roller, a pollution control and treatment system, a pollution monitoring system and a pelletizer. A device for the said improved eco-friendly recycling process of post-consumer waste plastics has also been devised to carry out the said process The device for the improved eco-friendly recycling process of post-consumer waste plastics includes a pollution treatment device, an extruder, i.e., an extrusion machine, through which the said second phase of the said recycling process passes wherein the said extruder having a screw with a diameter of at least 50.0 mm, screw pitch of at least 50.8 mm, motor with a speed of at least 1440 RPM and power of at least 6.17 H P connected to the said extruder, axial length of the said screw's threaded portion to its outside diameter ratio of at least 28:1, screw length of at least 1400 mm and capacity of at least 27 kg/hrs The device for the improved eco-friendly recycling process of post-consumer waste plastics including the extruder wherein the said screw of the said extruder is heat-treated by mtrtding to 65 Rc in order to increase the resistance to abrasion. The device for the improved eco-friendly recycling process of post-consumer waste plastics further including a flexible pipe wherein the said flexible pipe has a bending / curvature in such a manner that any suspended particle in the emitted gas would settle down before it enters the ID fan through which the said air/emitted gas pass. The device for the improved eco-friendly recycling process of post-consumer waste plastics wherein the said flexible pipe is clamped to the line m order to facilitate cleaning of the inside of the said pipe in an easier manner. 12 The device for the improved eco-friendly recycling process of post-consumer waste plastics wherein the said flexible pipe-inlet is connected to ajar / container, the diameter of the said pipe-inlet to the jar / container being more than that of the outlet pipe diameter to enhance the velocity of outgoing gases after dissolving in one liquid The device for the improved eco-friendly recycling process of post-consumer waste plastics wherein a pollution treatment device is devised in such a manner that byproducts from each jar / container is taken out through taps fixed at the bottom of each jar/ container that is connected to the said flexible pipe. 4. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The invention is described in the following in greater detail by way of an example with reference to the accompanying drawings in which Fig 1 shows a block diagram illustrating the improved eco-friendly recycling process of post-consumer waste plastics according to the present invention. Fig 2 shows a schematic diagram illustrating the improved eco-friendly recycling process of post-consumer waste plastics according to the present invention Fig 3 illustrates the device for the improved eco-friendly recycling process of post-consumer waste plastics according to the present inventioa Fig 3A depicts a side view of the ID pump engaged to the flexible pipe of the device of Fig 3 according to the present invention. Fig 3B illustrates an enlarged view of the extruder of the device of Fig 3 according to the present invention. 5. DESCRIPTION OF PREFERRED EMBODIMENT The main goal for developing green / eco-friendly recycling of post-consumer waste plastics, according to the present invention, was to design a waste plastics collection and segregation method, an extruder (1) which would have "Zero Significant Adverse Environmental Impact" This has been achieved by assigning right motor of minimum capacity, selecting optimum L/D ratio, heat sealing and right temperature for the processes and trapping all the emission in pollution control gadget (13) and treating the pollutants to produce byproducts 13 Data for various pollutants emitted (i e., VOCs, CO, NOx, SOx, HCL, CHOH, SPM etc ) during plastic processing have been collected during the recycling process & these data facilitates to modify the recycling process by which emission of air toxics are reduced The present invention has been initiated with an objective of developing a re-engineered recycling process of packaging plastic primarily focused on reducing environmental impact from extrusion in the recycling process, reducing environmental impact from plastics recycling process by reducing potential contamination of waste plastics by better collection and segregation method, enhancing awareness on use and eco-friendly disposal of plastics and creating awareness on implementation of plastic rule amongst recyclers and identified group of interested people. These shall certainly help to provide a better working environment. "Greening" the recycling process implies that the pollutants generated from the extrusion process is lesser and is controlled in such a manner so that the gaseous emission does not release into the atmosphere The extrusion and pelletization processes have been re-designed to make the pollution from the process to a minimum level and as a result to enhance the efficiency of the process The improved eco-friendly recycling process of post-consumer waste plastics, according to the present invention, has been delineated in Fig 1 and also in Fig 2. The facts narrated below are to be read with reference to both Fig 1 and Fig 2 under reference An improved eco-friendly recycling process of post-consumer waste plastics, according to the present invention, has two major phases The first phase is the process of collection and segregation of raw materials, i.e, post-consumer plastics wastes, from user and keeping at proper place/ bins, cutting, cleaning and pulping. The second phase includes extrusion and pelletisation processes of the said waste plastic products. The said improved process, according to the present invention, has been designed in order to reduce and control the emission generated during the said waste plastic recycling process. The said improved process of the present invention includes the following steps: identification of pollutants generated during recycling process of the said post consumer waste plastics; reduction of the level of emission to air to a minimum from recycling process thereby reducing energy consumption with better product quality, and reengineering extrusion process to reduce and control the emission generated during the said post-consumer waste plastics recycling During the collection and segregation process of the first phase, according to the present invention, potential contamination of the said post-consumer waste plastics are grossly 14 reduced The said collection and segregation process involves a few steps in reducing the hazards of pollutant at source. The steps are: segregation of the post-consumer waste plastics by the user in a separate bin with a mark / suitable coding system; collection of the said post-consumer waste plastics by municipal personnel in a specially designed two-compartment-cart having one compartment for plastics wastes and the other for municipal solid wastes; placing of the said post-consumer waste plastics in a separate collection bins at municipal solid waste collection center where from the recyclers or their representatives collect / purchase the said post-consumer waste plastics with lesser contamination to be used in plastics recycling extrusion or other processes. In order to reduce the level of emission to air, waste plastics are converted in the form of pulp like shape Before this, raw materials are collected from the supplier and kept at the proper place. The segregated High & Low-density polyethylene (HDPE & LDPE) are cut and /or cleaned with the help of detergent The cleaned plastic wastes are taken to a machine called agglomerator (not shown in drawings), or some time, in an unnamed low temperature heating arrangement (not shown in drawings) to convert plastic wastes in the form of pulp like shape which act as raw material for extrusion process In some cases the cleaned and cut plastic wastes are directly fed to the extrusion machine (not shown in drawings) Extrusion and pelletization are done by a barrel and screw type extrusion machine (1) with band electric heater Power is supplied from a motor and the screw barrel (not shown in drawings) is fed through a gearbox (not shown in drawings). Electric band heater (not shown in drawings) is heated through some electrical power source (not shown in drawings) Crushed / pulped / shredded raw materials are fed through the hopper (not shown in drawings) Output from the extrusion machine (I) is the wire shape plastics that are palletized to get plastic granules. The mixed agglomerates are fed into the hopper of the extruder (1) from where the material is passed into the feed zone of the machine (1). The screw (not shown m drawings) gets its drive from a 7.5 HP motor and a gearbox The screw & barrel (not shown in drawings) of the extruder (1) has no less than following four roles to play, viz., 1) It has to act as a pump, 2) It has to function as a heating chamber. 3) It is also a mixing device, and 4) It serves as a pressure vessel 15 The barrel and the screw section (not shown in drawings) of an extruder (1) are divided into three zones 1) a feed zone starting at the hopper, 2) a compression or transition zone, and 3) a melt or metering zone This division tallies with four principal functions of this unit namely, pumping, heating, mixing and pressurizing a) Feed Zone: This is the zone where the agglomerates (not shown in drawings) are fed and forwarded to the compression zone. The temperature in this zone is about 175°C In the feed zone, the granules are collected from the hopper and pumped (or transported) up along the screw channel (not shown in drawings). At the same time, it is to be ensured that these granules begin to heat up and if a screw for extruding a polymer having a wide melting range the corresponding zone of the screw is selected where compression takes place should be made longer. However, the feed zone has to be sufficiently long to ensure softening of the granules before they enter the transition zone In order to achieve maximum delivery of granules by the feed section, the following points are to be ensured a) compared to the rest of the screw, a relatively deep channel, b) a low degree of friction between the granules and screw, c) a high degree of friction between the granules and barrel and d) an optimum helix angle b) Compression Zone or Transition Zone: This is the zone where the agglomerates get compressed and take the form of sticky dough at a temperature of about 190° -200°C As the material advances towards the die end, compacting of the material is to be ensured. This has been done by increasing the root diameter to ensure availability of lesser space (or volume) to the advancing material Compression ratio influences melting rate and melting efficiency of the screw Compression ratio signifies the ratio of the volume of the first turn of the channel of the screw (at the hopper) to that at the last turn of the channel (at the die end) Compression ratio usually vanes from 1.5:1 to 4:1 c) Metering Zone or Melting Zone: This the final zone where the thread-like plastic is formed when the heated matter is pulled through the die (2). The temperature this zone is about 225°C 16 The last zone of the die-end is called metering zone or melting zone. A sufficiently large pulsation free reproducible and thermally and physically homogeneous melt stream is necessary to feed the die. In this zone it is to be made sure that the melt is homogenized and pumped to the die (2) at a constant rate, consistency and pressure. It is to be kept in view that all these three factors may vary from point to point along the length of the melting zone but at a given point along the screw, these three readings should be the same even if these are measured at different intervals of time during processing. By providing a shallow channel depth in metering zone, sufficient pressure build-up in the molten mass and a pulsation - free melt flow have been achieved. Besides, it can be ensured that the composition of the melt is uniform by adding special mixing sections, such as mixing rings (not shown in drawings), mixing pins (not shown in drawings), Maddox sections (not shown in drawings), etc in the metering zone In fact, when we achieve pressure build-up in the metering zone, that itself increases melt homogeneity. The increase in viscosity of the melt is obtained by lowering temperature while increase in resistance to melt flow in the die-adaptor helps to increase the melt pressure Some technical parameters/features guiding the process according to the present invention are explained below. 1. Barrel Length to Diameter Ratio (L/D); For any extruder (1), barrel inside diameter (nominally the same as screw diameter), and barrel length to diameter ratio (L/D) are very important The larger the bore or diameter, the more melt that can be pumped through it, and the greater the L/D - all else being equal - the more well-mixed or homogeneous the melt that can be delivered For an example, an extruder (1) of one embodiment of the present invention has screw diameter of 50 mm and length 1400 mm, and hence L/D ratio is 28 1 2. Barrel heating and cooling Barrels are typically designed for safe operation up to 700 atm. According to the present invention, an extruder (1) is fitted on the barrel's external surface (not shown in drawings) with six numbers of band heaters (not shown in drawings), each being of 1 KW There are three zones in the barrel as stated earlier. Adjacent pair of band heater (not shown in drawings) covers each zone. The barrel on its external surface is covered with heat insulation material in order to prevent waste of heat from the barrel surface, since this heat is essential for maintaining the melt flow. Feed and throat area of the barrel (not shown in drawings) is water-jacketed (not shown in drawings) in a chamber around this portion of the barrel, which is water cooled to prevent heat from the working section being conducted 17 back towards the throat where it could partially melt the plastic pellets and cause them to bridge across the throat 3. Breaker Plate At the end of the melt zone, a breaker plate (not shown in drawings) is provided in the extruder (1) according to the present invention. A breaker plate is a disc with several holes. The breaker plate has four functions, viz , 1. It holds back impurities such as un-gelled polymer, dirt, foreign bodies etc 2 It helps to increase head pressure by providing resistance to the pumping action in the metering zone 3 It converts the rotational flow of the melt into flow parallel to the screw axis, 4 It removes the turning memory from the melt 4. Die Die (2) has been illustrated in Fig. 3B of the accompanying drawings This the final zone where the thread-like plastic is pulled through the die (2). The temperature in this zone is about 240°C The forming zone or the die zone is always a 'pressure consuming' zone. The pressure built up in the preceding functional zones is used up in the die-forming zone The die head is also fitted with a heat sensor for its separate thermocouple for controlling the temperature precisely. It is to be noted that the product quality, output and operational efficiency of the extrusion plant largely depend upon the die (2) design. The basic features of a well - designed die (2) are listed here (i) specified volume throughput is achieved at minimum extrusion pressure, (ii) the melt being fed from the extruder (I) finds sufficient residence time m the die to achieve relaxation of stresses and equalisation of temperature; (ni)the melt emerges at the same accurate rate from the whole of the outlet cross-section of the die, (iv)the desired extruder (I) geometry is achieved for semi-finished products, (v) the surface of the extrudate remains smooth even at high volume outputs. (vi)there is no stagnation or decomposition of the extruded material Die (2) components have adequate mechanical stiffness to withstand high internal pressure The thread-like extruded plastic is passed through a number of rollers (not shown in drawings) and cooled in a stream of cold water (10), dried in cold air and fed into a pelletizer machine (not shown in drawings) where granules of required size are cut from the string Plastic granules thus produced may be used for production of different items as 18 is required. Plastic granules thus produced may be blended with virgin plastic granules for better quality of products. Since one of the objectives of the extrusion process, according to the present invention, is to melt the granules, heat has to be applied to these granules. This heat is generated partly internally by friction and partly by applying external heat from band heaters wrapped around the barrel. In some cases, the entire heating may be achieved only by internal friction. But it is to be taken care of that the heat supply (or input) is controlled properly. If the heat supply is too much, the material inside the barrel will get decomposed. On the other hand, if it is too less, the material will not be plasticised (or melted) sufficiently Another adverse effect of inadequate control of heat input is surges. The control of heat also helps in reducing waste of energy and hence the cost savings and better quality of products Melting process according to the present invention: Because of high fluid viscosity, the flow in a screw pump (here it is the extruder) (1) is invariably laminar rather than turbulent Large pressures can be generated owing to the high viscosities of the polymer melts. These pressures are normally generated at the delivery end of the screw. To understand (and be able to predict) the behaviour of plastics material being processed in the extruder (1), there is a useful and popular model known as Tadmer and Klein model This model assumes that the solid material in the extruder (1) rotates almost with the screw The material is further sheared when it comes into contact with the barrel inner surface The material receives heat by conduction (from the barrel inner surface). The result is a molten film of uniform thickness, which is collected by the screw flight and forms a molten stream on the leading face of the flight This molten stream is moving (with the screw) and as it moves past the solid bed of the polymer material it erodes this bed. This erosion is partly by heat transfer and partly by shear of the bed. As this process continues along the length of the screw, at some stage, the solid bed breaks up and forms a suspension. From this point on (up to die), the remaining length of the screw is used for pressure build up and mixing etc In this context, it is to be noted that polymers generally have low thermal conductivity Therefore, melting of solids by conduction of heat (from external heaters through barrel) is supplemented by shear heating. This mode of shear heating does not depend on temperature difference within the polymer and permits more rapid melting than by conduction alone 19 Besides, there is no risk of burning or degradation with shear heating Also, the low mechanical efficiency of about 10% of a screw extruder (1) makes it an ideal and effective means of melting organic polymers. Such polymers have high melt viscosity, low thermal conductivity and moderate thermal stability Greening the Recycling Process according to the present invention: For greening the recycling process means that the pollutants generated from the extrusion process is lesser and is controlled in such a manner so that the gaseous emission does not release into the atmosphere For reducing pollution level following steps have been adopted in the system, a) Separate unwanted material while feeding that causes pollution at source b) The temperature in different zones of the extruder (1) are controlled and kept as minimum as possible maintaining the quality of product c) The released gases from the die head is sucked into the pollution control gadget without allowing pollutants to be released into atmosphere, and d) These gases passed through the pollution treatment device (12) e) Intermediate pollution monitoring device (13) to know the level of pollution f) Release port for residual gases to atmosphere Monitoring & Measurement of Pollutants according to the present invention: The remaining quantities of the gases are passed through a set of impingers (14) containing 50ml of each of different chemicals viz., H2O2 (3% solution), NaOH (001 M Solution) and doubled distilled water that absorbs SO2, HC1 and HCHO respectively The out let of the impinger (14) is connected to a rotameter where airflow rate is maintained at 3 litres per minute (LPM). The rotameter is connected with a vacuum pump which discharges the air almost free from pollutant gases, to the atmosphere The system is absolutely eco-friendly Once a fortnight the samples may be checked for monitoring. The improved eco-friendly recycling process of post-consumer waste plastics has a pilot plant for recycling The said plant includes at least an electric power system (not shown in drawings), a control panel (not shown in drawings), a pre-heater (not shown in drawings), a gearbox (not shown in drawings) and motor (not shown in drawings) The reengineering process of plastic wastes includes an extruder (1), a hopper (not shown in drawings) of the said extruder (1), an electrical heating system (not shown in drawings) having heating means of the said extruder (1), insulation and cover of the said extruder (1), a screw and barrel of the said extruder (1), a die (2) and die head of the said extruder (1), a hood (4) & frame (11), a water tank (10) and roller, a pollution control and treatment system (12), a pollution monitoring system (13) and a pelletizer (not shown in drawings). A device for the said improved eco-friendry recycling process of post-consumer waste plastics includes a pollution treatment device (12), an extruder (1), i.e., an extrusion 20 machine that acts as screw pump (1), through which the said second phase of the said recycling process passes. The extruder (1), according to the present invention, has a screw (not shown in drawings) with a diameter of at least 50.0 mm, screw pitch of at least 50 8 mm, motor with a speed of at least 1440 RPM and a means for power of at least 6.17 H.P connected to the said extruder (1), axial length of the said screw's threaded portion to its outside diameter ratio of at least 28 1, screw length of at least 1400 mm and capacity of at least 27 kg / hrs. The screw of the said extruder (1) is heat-treated by nitriding to 65 Rc ('C scale of Rockwell hardness) in order to increase the resistance to abrasion A flexible pipe (6), according to the present invention, is clamped to the line with a 'C'-clamp (3) in order to facilitate cleaning of the inside of the said pipe (6) in an easier manner The flexible pipe (6) has a bending / curvature (9) in such a manner that any suspended particle in the emitted gas would settle down before it enters the ID fan (5) through which the said air/emitted gas pass. The flexible pipe-inlet (6) is connected to a jar / container (7), the diameter of the said pipe-inlet (6) to the jar / container (7) being more than that of the outlet pipe diameter (6) to enhance the velocity of outgoing gases after dissolving in one liquid Fig 3A illustrates an ID fan (5) fitted with a flexible pipe (6) with a 'C'-clamp(3) A pollution treatment device (12) is devised in such a manner that byproducts from each jar / container (7) is taken out through taps (8) fixed at the bottom of each jar/ container (7) that is connected to the said flexible pipe (6). The overall aim of an extrusion plant operator is to optimise the output. The means available for achieving this aim are enumerated below. 1 Change barrel temperature 2 Change screw speed 3 Change back pressure 4 Alter melt temperature 5 Change melt pressure 6 Improve mixing etc The output from an extruder (1) varies with the screw speed. It is observed that the total output increases as the screw speed increases. The pressure also increases with the increase in screw speed It has been observed that the concentration of all the three gases, viz., SO2, HCL gas and HCHO, emitted during the processes have been reduced by 80% to below detectable limit (BDL) in the green recycling process. HDPE contribute maximum amount of all the three gases in case of waste plastics that came down to 82 % to 95 % It has been concluded that 21 the eco-friendly / green recycling process has reduced the pollution level of the emitted gases during the extrusion by 82 % to 95 % which is beneficial for the environment as well as the human being and the society. It is to be understood, however, that although the characteristics and advantages of the present invention have been set forth in the foregoing description, the disclosure is illustrative only, and changes may be made in the arrangement of the parts within the scope of the appended claims. 22- List of Reference Numerals used in the accompanying drawings: I claim: 1 An improved eco-friendly recycling process of post-consumer waste plastics having two major phases, the first phase being the process of collection and segregation of raw materials, 1 e., post-consumer plastics wastes, from user and keeping at proper place/ bins, cutting, cleaning and pulping, and the second phase being extrusion and pelletisation of the said waste plastic products wherein the said process has the following steps to reduce and control the emission generated during the said waste plastic recycling process' identification of pollutants generated during recycling process of the said post consumer waste plastics, reduction of the level of emission to air to a minimum from recycling process thereby reducing energy consumption with better product quality; and reengineering extrusion process to reduce and control the emission generated during the said post-consumer waste plastics recycling. 2. The improved eco-fhendly recycling process of post-consumer waste plastics as claimed in claim 1, wherein potential contamination of the said post-consumer waste plastics are reduced during the said collection and segregation process, the said collection and segregation process involves segregation of the post-consumer waste plastics by the user in a separate bin with a mark / suitable coding system, collection of the said post-consumer waste plastics by municipal personnel in a specially designed two-compartment-cart having one compartment for plastics wastes and the other for municipal solid wastes; placing of the said post-consumer waste plastics in a separate collection bins at municipal solid waste collection center where from the recyclers or their representatives collect / purchase the said post-consumer waste plastics with lesser contamination to be used in plastics recycling extrusion or other processes. 3. The improved eco-friendly recycling process of post-consumer waste plastics as claimed in claim 1, wherein for the said reduction of the level of emission to air, post- consumer waste plastics are converted in the form of pulp like shape which act as raw material for extrusion process by agglomerator, or some time in an unnamed low temperature heating arrangement 4 The improved eco-friendly recycling process of post-consumer waste plastics as claimed in claim 1, wherein the said reengineering process passes through the steps of extrusion and pelletization performed by a barrel and screw type extrusion machine with band electric heater, 23 supplying power to the said extrusion machine (1) from a motor and feeding the screw barrel through a gearbox mounted on the said extrusion machine (1); heating an electric band heater through some electrical power source, feeding the said crushed / pulped / shredded raw material through hopper of the said extrusion machine (1), and palletizing the wire shape plastics resulted in from the said extrusion machine (1) to get plastic granules 5 The improved eco-friendly recycling process of post-consumer waste plastics as claimed in claim 1. wherein the process reduces environmental pollution level having the steps of controlling the temperature in different zones of the extruder (1) and keeping as minimum as possible maintaining the quality of product; sucking the released gases from the die head into the pollution control gadget without allowing pollutants to be released into atmosphere and also through the pollution treatment device (12); releasing port for residual gases to atmosphere, and producing usable by-products; passing these gases through intermediate environmental parameter monitoring gadget (13) consisting of a set of impingers (14), vacuum pump and pipeline (15) with valves (16), to know the level of pollution 6. The improved eco-friendly recycling process of post-consumer waste plastics as claimed in claim 5, wherein the said residual gases, viz., SO2, HCL gas and HCHO, emitted during the processes, being reduced by 80% to BDL in the green recycling process, are passed through a set of impmgers (14) containing 50ml of each of (d) 3% H2O2 solution that absorbs SO2, (e) 0.001 M NaOH Solution that absorbs HC1 and (0 doubled distilled water that absorbs HCHO 7 The improved eco-friendly recycling process of post-consumer waste plastics as claimed in claim 5, wherein the outlet of the said impinger (14) is connected to a rotameter where airflow rate is maintained at 3 litres per minute 8. The improved eco-friendly recycling process of waste plastic as claimed in claim 7, wherein an ID fan (5) connected to the said containers (7) of chemicals discharges the said air, almost free from pollutant residual gases, to atmosphere. 9. The improved eco-friendly recycling process of post-consumer waste plastics as claimed in any of the claims 1 to 8, having a recycling plant including at least an electric power system, a control panel, a pre-heater, a gear box and motor wherein the said reengineering process includes an extruder (1), a hopper of the said extruder (1), an 24 electrical heating system having heating means of the said extruder (1), insulation and cover of the said extruder (1), a screw and barrel of the said extruder (1), a die (2) and die head of the said extruder (1), a hood (4) and frame (11), a water tank (10) and roller, a pollution control and treatment (12) system, a pollution monitoring system (13) and a pelletizer 10 A device for the said improved eco-friendly recycling process of post-consumer waste plastics as claimed in any of claims I to 9, includes a pollution treatment device (12), an extruder (1), i,e, an extrusion machine (1), through which the said second phase of the said recycling process passes wherein the said extruder (1) having a screw with a diameter of at least 50 0 mm, screw pitch of at least 50.8 mm, motor with a speed of at least 1440 RPM and power of at least 6.17 H P connected to the said extruder (1), axial length of the said screw's threaded portion to its outside diameter ratio of at least 28:1, screw length of at least 1400 mm and capacity of at least 27 kg /hrs. 11 The device as claimed in claim 10. including the extruder (1) wherein the said screw of the said extruder (1) is heat-treated by nitriding to 65 Rc in order to increase the resistance to abrasion. 12. The device as claimed in claim 11, further including a flexible pipe (6) wherein the said flexible pipe (6) has a bending / curvature (9) in such a manner that any suspended particle in the emitted gas would settle down before it enters the ID fan (5) through which the said air/emitted gas pass. 13.The device as claimed in claim 12, wherein the said flexible pipe (6) is clamped with a 'C'-clamp (3) to the line in order to facilitate cleaning of the inside of the said pipe (6) in an easier manner. 14. The device as claimed in claim 13, wherein the said flexible pipe-inlet (6) is connected to a jar / container (7), the diameter of the said pipe-inlet (6) to the said jar / container (7) being more than that of the outlet pipe (6) diameter to enhance the velocity of outgoing gases after dissolving in one liquid 15. The device as claimed in claim 14, wherein a pollution treatment device (12) is devised in such a manner that by-products from each said jar / container (7) is taken out through taps (8) fixed at the bottom of each jar/ container (7) that is connected to the said flexible pipe (6) 25 16. An improved eco-friendly recycling process of post-consumer waste plastics and a device for carrying out the said improved process substantially as herein described with reference to the accompanying drawings To, The Controller of Patents, The Patent Office, Kolkata 26 The present invention relates to an improved eco-friendly / green recycling process of post-consumer waste plastics and a device thereof. The main goal for developing eco-friendly / green recycling of post-consumer waste plastics is to design an extruder (1), which would have "Zero Significant Adverse Environmental Impact". This has been achieved by assigning right collection method, right equipment, heat sealing and right temperature for the processes and trapping all the emission in pollution control gadget (12, 13) and treating the pollutants to produce by-products for commercial utilisation. The present invention identifies pollutants generated and reduces the level of emission to air to a minimum from the process thereby reducing energy consumption with better product quality. Collection & segregation methods for the recycling process of post-consumer waste plastics have been delineated in the present invention. The extrusion process has been re-engineered to reduce and control the emission generated during the post-consumer waste plastics recycling.

Documents:

00772-kol-2004 abstract.pdf

00772-kol-2004 claims.pdf

00772-kol-2004 correspondence.pdf

00772-kol-2004 description (complete).pdf

00772-kol-2004 drawings.pdf

00772-kol-2004 form-1.pdf

00772-kol-2004 form-18.pdf

00772-kol-2004 form-2.pdf

00772-kol-2004 form-26.pdf

00772-kol-2004 form-3.pdf

00772-kol-2004 letters patent.pdf

00772-kol-2004 reply f.e.r.pdf

772-KOL-2004-FORM 27.pdf