Chemical recycling process for converting contaminated plastic wastes into valuable products

Abstract

The present invention relates to a process for upcycling synthetic waste into valuable products. It offers a method for converting and managing mixed feedstock streams, including plastic waste, shredder residue, and other carbon- and hydrogen-rich materials. The process generates gas, oil, light hydrocarbons (e.g., circular naphtha), specialty chemicals, and carbon solids, which can be used directly or further refined.

Description

[0001] CHEMICAL RECYCLING PROCESS FOR CONVERTING CONTAMINATED

[0002] PLASTIC WASTES INTO VALUABLE PRODUCTS

[0003] DESCRIPTION

[0004] Technical Field

[0005] The present invention relates to a process for upcycling synthetic waste into valuable products. It offers a method for converting and managing mixed feedstock streams, including plastic waste, shredder residue, and other carbon- and hydrogen-rich materials. The process generates gas, oil, light hydrocarbons (e.g., circular naphtha), specialty chemicals, and carbon solids, which can be used directly or further refined.

[0006] State of the Art

[0007] As the world faces the depletion of finite natural resources, the intensifying consequences of climate change, and the surging demand for sustainable materials and energy, the need for innovative solutions to reduce reliance on conventional raw materials has reached a critical point. Moreover, the vast and increasing generation of waste, particularly plastic and other non-biodegradable materials, further complicates environmental challenges. Existing waste management systems struggle to cope with these rising volumes, exacerbated by outdated infrastructure, limited landfill space, and inefficiencies in recycling processes. Addressing these issues requires urgent and holistic approaches to resource management and waste reduction.

[0008] Today's waste stream is increasingly dominated by materials such as primary process solids (PPS), which include plastic and rubber waste, along with other carbon- and hydrogen-containing substances. PPS, largely derived from urban and industrial sources, often contains considerable amounts of non-degradable plastic that pose severe environmental hazards to both land and marine ecosystems. Improper disposal of plastic waste can lead to contamination of groundwater and contribute to widespread environmental degradation. Moreover, the slow decomposition of plastics in nature exacerbates the problem, resulting in elevated greenhouse gas emissions and harmful disruptions to ecosystems and water sources. The effective management and disposal of polymeric waste have become increasingly critical, especially with the rise in population density. In recent years, the growing demand for plastics has driven a substantial surge in polyolefin production.

[0009] Global thermoplastic production currently stands at around 350 million tons annually and is expected to surpass 580 million tons by 2050, driven primarily by the growing use of polyolefins and polystyrene. Polyolefins alone account for more than half of all plastic production, with much of this material used in disposable products that quickly enter the waste stream. Unlike organic waste, plastic waste is not biodegradable and can remain in the environment for hundreds of years, posing significant long-term environmental challenges. This growing accumulation of plastic waste underscores the urgent need for more sustainable waste management solutions. As of the most recent data, global plastic production remains on a rapid growth trajectory, with annual figures increasing by 3-4% over the last few years. The long-lasting impact of plastics continues to drive concerns about their environmental footprint.

[0010] Polyolefins, which include polyethylene (PE) and polypropylene (PP), are among the most widely produced plastics globally, largely due to their versatility and use in a wide range of products, from packaging materials to household items. These plastics are particularly challenging in terms of waste management because they are used in large quantities and often in disposable products, contributing significantly to plastic pollution. Beyond polyolefins, other polymers such as polyethylene terephthalate (PET), commonly found in beverage bottles. Additionally, materials like polyvinyl chloride (PVC), polystyrene (PS), and rubber, including tires, add complexity to recycling processes due to their specific chemical properties. To effectively combat plastic pollution, a targeted approach to managing and recycling both polyolefins and these other polymers is essential, requiring tailored strategies that address the unique challenges each material presents.

[0011] Plastic recycling is often hindered by the complexities involved in separating different types of plastics, each with varying molecular weights, densities, additives, and fillers. These variations make it difficult to achieve high-quality products through mechanical recycling, as the process relies on proper sorting and uniformity of materials. In many cases, the resulting recycled plastic suffers from downgraded properties, such as reduced strength and durability, limiting its applications and value. To address the shortcomings of mechanical recycling, chemical recycling has emerged as a promising alternative. This process involves breaking down plastics and rubbers into their basic building blocks, which can be used to produce new plastics, chemicals, or even fuels. Techniques like pyrolysis, depolymerization, hydrolysis, and steam cracking enable the recycling of mixed or contaminated plastics that are difficult to process mechanically. Chemical recycling has the potential to handle a wider range of plastic types, including polyolefins, which dominate the global plastic production landscape, and other polymers like PET and PVC. However, chemical recycling faces its own challenges, such as high energy consumption, scalability issues, and cost-effectiveness. Additionally, developing robust collection and sorting systems, increasing public awareness about recycling, and creating strong markets for recycled products are critical to making these processes more viable. Addressing these challenges requires collaboration across industries, governments, and communities to advance recycling technologies and promote a circular economy for plastics, where waste is continuously reused rather than discarded.

[0012] The management of industrial waste, particularly shredder residue, presents a significant challenge. Shredder residue consists of nonmetallic parts from automobiles and other large appliances, such as air conditioners, refrigerators, dryers, and dishwashers, collectively known as white goods, and from other industrial goods. The shredder industry recovers approximately 10-12 million tons of ferrous scrap annually, primarily from vehicles. However, for every ton of steel recovered, about 250 kg of shredder residue is produced. While many components from end-of-life vehicles and appliances can be recycled, reused, or recovered, a large portion of the residue generated during shredding still ends up in landfills. This waste is further complicated by the presence of hazardous materials like cadmium, lead, mercury, and other heavy metals. With shrinking landfill space and the rising costs of hazardous waste disposal, there is a growing need for alternative approaches. The automotive and recycling industries are facing increasing pressure to develop cost-effective, energy-efficient solutions for managing shredder residue. Despite the use of various waste management techniques, many are either impractical, lead to additional pollution, or are expensive in terms of both energy and cost. Methods such as composting, incineration, landfill disposal, agricultural application, and ocean dumping each come with their own set of drawbacks, limiting their overall effectiveness.

[0013] Alternative waste management methods, such as incineration, bioremediation, pyrolysis, and gasification, pose specific challenges, particularly for plastic waste. For instance, bioremediation through aerobic and anaerobic digestion requires extended residence times, which are often impractical for plastics. It also demands precise control and monitoring of conditions like oxygen levels, pH, and temperature to promote specific microbial activity, as well as specialized equipment. This approach can result in inconsistent treatment outcomes and may generate products containing pathogens. Moreover, genetically engineered bacteria designed to target specific compounds can switch to alternative enzyme systems when exposed to a waste substrate, allowing them to process different compounds. Meanwhile, incineration requires specialized equipment and components to meet stringent emission standards. Chemical recycling of plastics, particularly through pyrolysis, has been used to break down plastic waste into valuable products such as gas, oil, and carbon-rich residues. In pyrolysis, plastics are heated to high temperatures, typically between 400-800 °C, in the absence of oxygen. While this method is effective for certain plastics, such as polyolefins (e.g., polyethylene and polypropylene), it often faces challenges with energy efficiency and product consistency. One major issue is the presence of impurities in plastic waste, including engineering plastics, PVC, rubber, and other organic materials. These impurities can introduce contaminants into the final products, making them less suitable as raw materials for the chemical industry. As a result, additional and costly refining steps are required to purify the output, raising the overall costs of chemical recycling. This lack of control over product quality, combined with the energy demands of the process, can make chemical recycling economically unviable. A more efficient approach would involve the implementation of cost-effective methods for removing contaminants before or during the recycling process, improving both the quality of the end products and the feasibility of the method.

[0014] An auger reactor is used as a cracking device in the pyrolysis-based chemical recycling of plastics, enabling the thermal decomposition of plastic waste into valuable hydrocarbon products. It employs a rotating auger screw that steadily moves shredded plastic feedstock through a heated chamber, operating in an inert atmosphere to prevent combustion. By exposing the plastics to high temperatures, the reactor efficiently breaks down long-chain polymers into liquid hydrocarbons, gases, and solid char. This continuous process offers a scalable solution for converting mixed plastic waste into reusable fuels and chemical feedstocks, supporting the increasing demand for sustainable waste management.

[0015] Gasification, a process involving the partial combustion of waste materials at high temperatures, is currently not an ideal solution for processing plastic waste. While it converts waste into syngas (a mixture of hydrogen and carbon monoxide) and char, the value of these outputs is relatively low compared to other chemical recycling methods. The syngas produced often contains impurities that require extensive and costly cleaning before it can be used in further chemical processes or energy production. Moreover, gasification struggles with the diverse composition of plastic waste, which often includes a mix of contaminants, such as additives or non-plastic materials. This makes the process less efficient and reduces the economic return. As a result, gasification is typically better suited for processing low-cost, pure feedstocks that do not require significant cleaning or purification, rather than complex or contaminated plastic waste.

[0016] Both pyrolysis and gasification methods often result in products with high impurity levels, including substances like tar and asphalt, and the products tend to have low calorific value. When plastic waste contains elements like nitrogen, oxygen, sulfur, and chlorine, it can lead to the formation of nitrogen-based compounds, oxygenated compounds, sulfur-containing compounds like mercaptans, and chlorides in the final output. For fuel or chemical applications, hydrocarbon feedstocks typically need chlorinated hydrocarbons to be present in very low concentrations, usually 1-2 ppm. However, neither pyrolysis nor gasification consistently achieves such low levels of contamination without additional processing. Furthermore, the energy efficiency of these methods is often constrained to around 30%, primarily due to inefficient heat transfer, uneven treatment of materials, and the energy-intensive processes needed to remove water from the waste feedstocks. This limits their practicality for producing high-quality products directly from plastic waste.

[0017] Recent developments outlined in U.S. Patents 8,877,992, 5,269,947, 5,360,553, and 5,543,061 have concentrated on enhancing the quality and performance of oils obtained from waste materials. However, these approaches may encounter challenges, such as handling nitrogen-, oxygen-, sulfur-, and chlorine-containing compounds, as well as inefficiencies in processing plastics and rubber. Additional issues, including melting difficulties, complex transfer operations, the requirement for specialized hydrolysis methods, and high energy consumption, further hinder their broad commercial implementation. These challenges highlight the need for sustainable recycling processes that are technically practical, economically viable, and environmentally friendly.

[0018] The present invention significantly improves upon existing patents by providing a more efficient and streamlined method for converting mixed plastic waste into valuable hydrocarbons. In comparison to the two-step process outlined in US20230012831A1, which involves pre-treating liquefied waste plastics (LWP) through aqueous contact and subsequent hydrotreating, the current invention utilizes a continuous auger reactor for pyrolysis, enabling the conversion of plastic waste in a single step and thereby reducing complexity and energy consumption. Furthermore, it contrasts with the method described in WO2024105644A1, which focuses on transforming municipal solid waste into thermoplastic materials through heating and instantaneous pressure reduction. This invention also offers advantages over US5190226A, which employs a pressure vessel for the separation and recycling of municipal solid waste via steam introduction and extrusion, as well as US10563036B2, which addresses the viscosity of recycled polyester through hydrolytic degradation in an extruder. By specifically targeting plastic waste and eliminating the need for multiple stages of chemical treatment and separation, the current invention presents a more practical and cost-effective solution for recycling, addressing the growing demand for sustainable waste management technologies.

[0019] CN106635115 relates to a method for efficiently and cleanly producing oil from mixed waste plastics using a hydrothermal reaction system. The method comprises the steps of subjecting mixed waste plastic to pyrohydrolysis under conditions of 160 °C to 300 °C and 20 bar to 220 bar, in the presence of an alkaline aqueous solution. This alkaline solution ensures that The waste plastic feedstock contains one or more of PE, PP, PS, and PET, and may optionally include PVC. After hydrothermal treatment, the resulting material is separated into a water phase and a solid phase, with the solid phase subsequently processed to produce oil. This process relies on a liquid phase alkaline hydrolysis at high temperatures and pressures, making it a challenging process.

[0020] US7771699 relates to a process for converting low-value mixed feedstocks, such as shredder residue, offal, manures, sewage sludge, tires, and plastics, into useful products including oils, gases, carbon solids, and specialty chemicals. The process employs heat and pressure, combined with thermal or catalytic cracking, in one or more stages to separate and upgrade components. The invention also relates to an apparatus for carrying out the multi-stage conversion and to oil products obtainable from the process, as well as other useful products derived from materials diverted at different stages. The process includes the use of a aqueous alkalic solution which offers problems related to high temperature and pressure and heat transfer.

[0021] Summary of the Invention

[0022] The invention focuses on developing a process for generating sustainable energy, hydrocarbons within the naphtha and gasoil boiling point range, fuel, raw materials, specialty chemicals, carbon char, and other valuable products from plastic waste streams. In some embodiments, the method may comprise mixing (ground) plastic waste with certain mineral materials or solutions or injecting the mineral material into the melt section of the extruder without prior mixing. The applied mineral materials primarily consist of strong bases or certain salts of strong bases or acids. The molten plastic is then injected, with or without the use of a melt pump, into a reactor where it is subjected to high temperature and pressure, converting it into various products such as fuel, hydrocarbons within the naphtha and gasoil boiling point range, sustainable energy, hydrocarbons, fuel, gas, char, and others.

[0023] In alternative embodiments, this method may include the hydrolysis of specific contaminants, such as engineering plastics, PVC, and other organic compounds present in polyolefin-containing waste within the extruder or other suitable mixing equipment, possibly capable to apply low, medium or high shear forces. The invention also provides waste treatment techniques and apparatus. Some configurations use primarily polyolefin plastic waste as input, while others involve polyolefin plastic waste combined with different types of plastic and non-plastic waste. Additionally, some configurations employ shredder residues as feedstock. There are also setups where the feedstock consists of a mixture of any of these types in varying proportions and with different initial moisture (including water) content. Various embodiments of this invention offer advanced solutions for producing energy and petroleum feedstocks that are both environmentally and economically sustainable. The methods outlined achieve a higher net energy value (NEV) compared to conventional techniques like incineration, pyrolysis, and gasification, while also tackling waste management issues. These embodiments effectively handle contaminated and unclean materials, including plastic waste streams, medical waste, municipal solid waste (MSW) and shredder residues, which are typically expensive and energy-intensive to dispose of. The processes convert these materials into valuable products, such as hydrocarbon liquids in the naphtha and gasoil boiling point range, solid carbon, fuel oil, fuel gas, and other useful intermediates. These intermediates can be selectively extracted at different stages and further processed into usable energy forms, such as fuel, or used as is or transformed into feedstocks for fuel and chemical production, as well as for creating a variety of specialized chemicals.

[0024] Another notable advantage of this invention is its capability to efficiently convert mixed and / or unsorted waste plastic streams into valuable products. These plastic feedstocks vary significantly in handling properties, resistance to conversion, and energy and carbon content— factors that are critical when integrating them into a refinery or chemical processing setting with waste feed. The invention's versatility in addressing these challenges demonstrates its exceptional and superior performance compared to traditional technologies.

[0025] In many chemical recycling processes, plastic waste— including biomass, engineering plastics like PET, PA, PC, and PVC— is separated through pretreatment methods and water washing, which can pose its own environmental challenges. This also applies to polyolefins with high mineral filler content, as their density becomes greater than that of water. This approach processes all plastics after removing stones and metals, providing a notable advantage compared to other methods.

[0026] Unlike conventional methods, the embodiments of this invention can manage waste substrates containing sulfur, nitrogen, oxygen, halogen, and other elements while still producing products with very low levels of impurities. This enables the direct use of the products without requiring additional processing. Evaluating the environmental benefit of a process involves considering not just the type of feedstock used but also the energy efficiency of the process, which impacts the Net Energy Value (NEV) and the net CO2 footprint of the final products. Therefore, the impressive efficiency of the methods and apparatus described here in managing wet feedstock, utilizing moisture content to drive the process, and effectively sterilizing the feedstock is particularly notable.

[0027] Figures

[0028] Figure 1 : a flowchart illustrating an exemplary process according to the invention. Figure 2: a schematic diagram depicting exemplary apparatuses used to perform an exemplary process of the invention.

[0029] Figure 3: a flowchart illustrating a thermal cracking stage of an embodiment of the invention.

[0030] Figure 4: a block diagram illustrating an exemplary process of the present invention adapted for full scale processing of plastic wastes.

[0031] 100. Primary Process Solids, PPS

[0032] 110. Preparation

[0033] 120. Hydrolysis Stage

[0034] 134. Secondary Process Solids, SPS

[0035] 135. Steam

[0036] 140. Cracking

[0037] 142. Carbon solids

[0038] 144. Naphtha

[0039] 146. Fuel-gas

[0040] 148. Condensation

[0041] 149. Oil

[0042] 150. Separation

[0043] 152. Heavy Oil

[0044] 220. PPS storage tank

[0045] 252. Extruder

[0046] 260. Cracking reactor

[0047] 280. Product oil storage

[0048] 500. Hydrolyzed PPS

[0049] 540. Carbon storage

[0050] 630. Carbon solids cooker

[0051] 850. Cooler

[0052] 1002. Metal detector

[0053] 1004. Grinding 1006. Grinder

[0054] 1008. Agglemorator

[0055] 1051. Distillation Tower

[0056] 1052. High pressure flash vessel 1053. Distillation Tower

[0057] 1054. Compressor

[0058] 1055. Distillation Tower

[0059] 1056. High pressure flash vessel

[0060] 1057. Low pressure flash vessel

[0061] Detailed Description of the Invention

[0062] The present invention relates to a process for upcycling synthetic wastes into valuable products. It offers a method for handling and processing mixed plastic feedstock streams and shredder residue to produce gas, oil, naphtha, specialty chemicals, and carbon solids. These outputs can be used directly or subjected to further refinement. Valuable products can be extracted or integrated at different stages of the process to optimize system efficiency. In this context, "sustainable energy" refers to energy sources that are not derived from fossil fuels. Examples of sustainable energy sources include solar, hydropower, wind, geothermal, wave energy, nuclear energy, and energy obtained from waste and other renewable resources.

[0063] In this context, "plastic waste" refers to waste that consists of polyolefins, along with other plastics such as engineering plastics and PVC. These waste streams may also include synthetic and organic materials, such as rubber, soil, and other organic substances, as well as inorganic materials like minerals, glass, metals, ceramics, and other non-organic substances. Additionally, this waste generally contains some moisture.

[0064] The term "biomass" as used here, refers to organic material obtained from plants, fungi and animals.

[0065] "Shredder residue," abbreviated as "SR" and also referred to as shredder fluff, denotes the material left after the extraction of most metals and glass from shredded or dismantled vehicles, appliances, consumer goods and industrial goods. Without the present invention, these materials often end up in landfills.

[0066] Shredder residue encompasses a diverse range of materials, including fragments of plastics (such as thermoplastics, thermosets, and polyurethane foam (PUF)), rubber, wood, paper, elastomers, fabrics, glass, fines, and residual ferrous and non-ferrous metal pieces. It may also contain various substances like paints and tar in different sizes. Shredder residue from old television sets, refrigerators, and other consumer goods— often referred to as white goods— can include hazardous substances such as heavy metals and polychlorinated biphenyls (PCBs), which are harmful chlorinated compounds. Additionally, shredder residue may contain other toxic elements, including polybrominated diphenyl ethers (PBDEs), which are used as flame retardants and are chemically similar to PCBs, as well as phthalates found in polyvinyl chloride (PVC), a material commonly used in automobile manufacturing.

[0067] Typically, shredder residue is a mixture of solids and liquids. The liquids typically originate from the shredded entities. The liquids can be of water- or oil-based substances or the mixture of these.

[0068] In the context of the embodiments of the present invention, terms like "react," "reacting," and "reaction" encompass a wide range of chemical or physical changes. Specifically, "reaction" refers to a chemical process resulting from the interaction or combination of two or more substances to yield one or more products. It also includes various forms of decomposition or conversion, where a single substance undergoes breakdown or transformation under conditions of temperature, pressure, or exposure to electromagnetic radiation. Additionally, these terms can describe transformations occurring in a solvent environment.

[0069] In this discussion, the term "PPS" (100), or "Primary Process Solid," refers to plastic and rubber waste originating from both pre-industrial, post-industrial, pre-consumer and post-consumer sources. This includes shredder residue and other mixed waste types that may contain materials such as polyolefins, PVC, engineering plastics, tires, and similar substances. The primary process solid (100) covers a broad spectrum of materials, including polyethylene, polypropylene, polystyrene, PET, polyester, polycarbonate, textiles, minerals, biomass, fats, rubber, tires, polyurethane, polyamide, and other synthetic and natural plastics and polymeric materials.

[0070] In this context, "SPS" (134), or "Secondary Process Solid," denotes the strong bases or their solutions utilized as hydrolysis aids in the extruder. This includes a range of bases such as NaOH, KOH and lime, as well as various salts like calcium carbonate, sodium (bi)carbonate, potassium (bi)carbonate, their mixtures whether in dry form or as a slurry.

[0071] The upcycling process converts synthetic and organic wastes into sustainable energy, liquid hydrocarbons (144), intermediate feedstock, and other valuable products with consistent purity, using water, heat, and pressure.

[0072] Embodiments of this invention utilize water, hydrolyzing agents, heat, and pressure across multiple stages to convert PPS into valuable products, including liquid hydrocarbons within the naphtha and gasoil boiling point range, fuel, feedstock, gas, and other items. Initially, PPS is prepared in a compacted or agglomerated form. It is then introduced into an extruder where the hydrolysis process begins, aided by hydrolyzing agents such as NaOH, KOH, lime, or their mixtures. During this process, heterogeneous bonds— such as carbon-oxygen, carbon-nitrogen, and carbonsulfur— are broken, resulting in various chemical salts. Simultaneously, organic liquids and solid particles undergo further reactions due to the elevated temperatures and pressures, breaking down complex organic molecules into simpler compounds through hydrolysis. This results in a hydrolyzed PPS (500) stream with a lower molecular weight than the original feedstock, which is then fed into a cracker. Figure 1 provides a high-level block diagram illustrating exemplary embodiments of this invention, with further details of the processes and devices depicted in subsequent figures and explained below.

[0073] Embodiments of the current invention are designed to handle and process a mixed stream of PPS without requiring initial sorting into separate, pure streams. In certain embodiments, as depicted in the Figures, the PPS (referred to as "raw material") may undergo an optional feed preparation stage (110) prior to entering the extruder. This stage involves treating the PPS through shredding, grinding, compacting, and / or agglomerating to facilitate smooth conveying, as shown in Figures 1 and 3. Alternatively, the feed preparation stage (110) aims to improve the flowability of the raw materials, enhancing their movement, heat transfer, and mixing during subsequent processing stages.

[0074] Feedstock preparation (110) involves a series of steps designed to optimize the raw material for subsequent processing. This process includes metal removal (1002), shredding (1004), grinding (1006), and compacting / agglomerating (1008), which may be performed separately or in combination, potentially with preheating. Compacting and / or agglomerating can increase the bulk density of the plastic and potentially double the extrusion speed. An additional pretreatment step may involve washing the Primary Process Solid (PPS) after grinding (1004) to remove a significant portion of contaminants, such as engineering plastics, PVC, and various water-soluble organic compounds. The goal of this preparatory phase is to enhance the consistency and cleanliness of the feedstock, thereby improving overall system efficiency and product quality.

[0075] As detailed in the following disclosure, embodiments of the current invention may utilize wet grinding (1004) to aid in the movement of materials through pipes, tanks, and other equipment within the system. Larger particles are moved through the process as described earlier.

[0076] Those with ordinary skill in the field will recognize that to increase the extruder output, the bulk density must be significantly raised, ideally above 0.3 g / cm3. Conversely, while lower moisture levels facilitate the melting process within the extruder, a small amount of moisture— typically a few percent— can actually enhance the efficiency of the hydrolysis process inside the extruder. In accordance with embodiments of the current invention, incoming streams can be processed without the need for prior separation of water (up to a few percents) and other contaminants, which is often required by conventional methods that struggle with wet feedstock and prioritize their removal first. Instead, these embodiments leverage the water already present in the feedstock to improve efficiency, assisting in the removal of contaminants and toxic chemicals from organic streams. Feedstock preparation (110) and slurring can be performed using a feedstock preparation (110) apparatus, as illustrated in Figure 2.

[0077] As depicted in Figure 2, the preparation (110) and compacting (1008) of PPS (100) can be carried out using the raw material preparation machine (110). Once the PPS (100) is prepared, it is introduced into the feed stream and transferred to the PPS storage tank (220). At this point, the PPS (100) can either be mixed with SPS (134) and sent directly to the extruder or, alternatively, the compacted plastic can be fed through the extruder hopper while SPS is delivered via a pump, either as a solution or powder, to the center of the extruder where the plastic is melting. The necessary reduction in material size depends on the composition of the PPS (100); optimal particle sizes generally range from 0.1 mm to 100 mm, with a preferred range of 2 mm to 50 mm, and ideally from 5 mm to 30 mm. Additionally, the bulk density can vary from 0.01 to 1.1 g / cm3, with a preference for 0.1 to 1.0 g / cm3, and ideally from 0.3 to 0.6 g / cm3.

[0078] For practical purposes, the compacted PPS (100) particles are ideally sized between 6 to 10 mm with suitable bulk density between 0.3-1.0 gr / cm3to ensure efficient extrusion alongside the SPS (134). The initial particle size generally depends on the capacity and capabilities of the equipment used. Following the raw material preparation (110) step, the particle size should be adjusted to meet the requirements of subsequent treatments in the process. In alternative embodiments of the invention, the feed preparation (110) step may involve adding or removing materials from the raw materials, essentially performing specific pretreatments to refine the plastic content.

[0079] The hydrolysis process, while having a minimal impact on polyolefins, may slightly reduce their molecular weight within the extruder. Polyolefins, such as polyethylene and polypropylene, are relatively resistant to hydrolysis due to their strong carboncarbon bonds, but their molecular weight can still be reduced to some extent. During hydrolysis, contaminants and other polymers with heteroatoms, like nitrogen or sulfur, are more susceptible to breakdown. The hydrolyzed PPS (500) stream, now enriched in polyolefins and other polymers with reduced heteroatom content, is then directed to a unit for further processing. This enrichment helps in improving the quality and consistency of the final products, as the presence of heteroatoms can often lead to undesirable impurities and affect the efficiency of subsequent processing stages.

[0080] The hydrolysis stage (120) within the extruder typically operates at temperatures ranging from 50 °C to 450 °C. Preferred temperature ranges are from 80 °C to 425 °C, with more optimal conditions between 150 °C and 400 °C, and ideally between 300 °C and 350 °C, depending on the starting material. Proper temperature control is essential to minimize or prevent the formation of char, ash, resin, or other undesirable reactions, ideally avoiding coal, coke or ash production. The duration of the hydrolysis step generally ranges from about 0.1 minute to 60 minutes. Preferred durations are from 0.2 minutes to 10 minutes, with more precise intervals from 0.3 minutes to 5 minutes, and ideally from about 0.5 minutes to 2 minutes. The processing time can vary based on the applied conditions; for instance, it may be less than 1 minute at higher temperatures or extend beyond 5 minutes at lower temperatures, as understood by experts in the field. Raising the temperature to these levels reduces the plastic's overall viscosity and aids in breaking down various components for subsequent processing. For example, organic materials are broken down into smaller molecular weights, resulting in shorter chains. Conversely, the quantity of SPS is crucial to the hydrolysis process. Typically, the proportion of SPS relative to PPS can range from 0% to 60%. For optimal conditions, this range is usually between 0% and 20%. Under very optimal conditions, the proportion may be between 0% and 10%, with the most effective range for feeds primarily composed of polyolefins being between 0.1% and 5%.

[0081] During the extrusion of PPS (100), plastics are melted, rubber is at least partly devulcanized, and long-chain molecules are at least partly broken down into smaller components. In an exemplary implementation of the hydrolysis stage (120), as shown in Figure 2, the Feed Storage (220) ensures a continuous feed stream to the extruder. The extruder (252) blends SPS (134) with PPS (100) and transfers the mixture to the cracker (260) for further processing. The extruder (252) can be designed using conventional technologies, such as single or twin-screw extruders, which provide the necessary mechanical action and heat to initiate hydrolysis and other reactions. This design allows for efficient mixing, breakdown of complex materials, and transport of the feedstock through the system. The choice between single and twin-screw extruders may depend on factors such as feed composition, desired output, and operational efficiency. Twin screw extruders, for example, are often favored for their enhanced mixing and shearing capabilities, particularly in handling materials with varying viscosities or moisture levels, making them ideal for complex feedstocks like PPS.

[0082] The hydrolysis of plastics within an extruder, using lime (calcium hydroxide) or sodium hydroxide (NaOH) or potassium hydroxide (KOH), facilitates the breakdown of specific types of plastics, particularly those with ester or amide linkages, such as polyesters (e.g., PET), polycarbonates or polyamides (e.g., nylon). Inside the extruder, the combined effects of heat, pressure, and the alkaline environment generated by lime, NaOH or KOH significantly speed up the hydrolysis process.

[0083] In this process, the high temperature and mechanical shear within the extruder help to break down the polymer chains. The introduction of lime, calcium carbonate, NaOH or KOH supplies hydroxide ions (OH“), which attack the ester or amide bonds in the plastic, causing these bonds to break and leading to decontamination. This method eliminates the need for a separate hydrolysis reactor, as the plastic is directly fed into the extruder (252) along with a strong base, such as NaOH, KOH or lime, in a specific ratio of around 0-30%, ideally 0.1-3% relative to the plastic. The hydrolysis process then occurs within the extruder itself.

[0084] As illustrated in Figure 1, during the hydrolysis process, the compacted PPS (110) is introduced into the hydrolysis stage (120), where it undergoes elevated temperatures and pressures within the extruder (252). This process promotes the removal of heteroatoms and facilitates the breakdown of long-chain molecules into shorter ones. The hydrolysis stage (120) typically operates at temperatures between 50 °C and 450 °C, with preferred ranges from 80 °C to 425 °C, more optimally from 150 °C to 400 °C, and ideally between 300 °C and 350 °C, depending on the composition of the feedstock. This phase can involve transformations such as deoxygenation, denitrogenation, desulfurization, dechlorination, decarbonylation, and decarboxylation, as well as organic decontamination, partial depolymerization, isomerization, and cyclization of polymer chains. Additionally, the process produces chemical salts as byproducts, depending on the type of contaminants present in the feedstock.

[0085] The hydrolysis stage (120) creates optimal conditions for the removal of gaseous impurities, including ammonia, nitrogen oxides, HCI, carbon monoxide, carbon dioxide, and sulfur-containing gases. These sulfurous gases are released as a result of the breakdown of sulfur-based compounds in the feedstock, which may include rubber and various organic contaminants. The combination of heat, pressure, and duration in this phase not only facilitates the release of these impurities but also ensures the effective destruction of pathogens within the waste. Consequently, embodiments of this invention are suitable for sterilizing and processing biological waste.

[0086] Heterogeneous bonds, including those involving elements like oxygen, sulfur, nitrogen, and chlorine, are typically more susceptible to breaking under high- temperature and high-pressure conditions due to several factors. First, these bonds often possess lower bond dissociation energies compared to carbon-carbon bonds, making them more fragile in extreme environments. Additionally, the presence of significant covalent bond polarization in these bonds results in uneven electron distribution, which further increases their reactivity. When sodium hydroxide (NaOH), potassium hydroxide (KOH) or lime is introduced into the process within the extruder (252), it acts as a strong base and plays a key role in breaking these bonds through chemical reactions. For example, NaOH reacts with chlorine-containing compounds, such as polyvinyl chloride (PVC), to form sodium chloride (NaCI) and water, effectively neutralizing the chlorine and preventing the release of harmful HCI gas. In sulfur-containing compounds, NaOH can react to form sulfates or other sulfur salts, helping to capture and neutralize sulfur contaminants. Nitrogen-based compounds, such as amines or nitriles, can undergo reactions with NaOH to form ammonia or other nitrogen derivatives, which are then easily vented as gases. Under the conditions inside the extruder (252), where both heat and pressure are elevated, and a strong base such as NaOH is present, the chemical environment becomes highly conducive to breaking these weaker heterogeneous bonds. This facilitates the removal of contaminants like sulfur, nitrogen, and chlorine, allowing for the cleaner conversion of waste materials into more valuable products. By breaking these bonds and neutralizing harmful byproducts with NaOH, the process ensures efficient decontamination and minimizes the release of hazardous substances typically associated with conventional plastic waste processing methods.

[0087] The hydrolysis process is highly effective at reducing contamination in the final products due to its ability to break down complex chemical bonds in waste materials, particularly those involving heteroatoms such as oxygen, nitrogen, sulfur, and chlorine. These heteroatoms are removed or neutralized in the presence of NaOH, which reacts with contaminants to form less harmful compounds like salts (e.g., sodium chloride from chlorine or sodium sulfide or sodium sulfate from sulfur). These reactions not only decontaminate the material but also facilitate the separation of different components in the feedstock. Under the extruder (252) conditions, engineering plastics, which typically contain ester or amide linkages, are likely to undergo hydrolysis, breaking down into their primary monomers. These monomers, such as ethylene glycol from PET or caprolactam from nylon, are more water-soluble than polyolefins and can be easily separated due to their hydrophilic nature. Additionally, the removal of heteroatoms from these engineering plastics, catalyzed by strong bases such as NaOH, can transform these compounds into substances with properties more similar to polyolefins, further aiding their separation.

[0088] Polyolefins, on the other hand, are more resistant to hydrolysis but are still affected by the elevated temperatures and pressures within the reactor. These conditions, combined with the presence of NaOH, cause the polyolefin chains to crack, reducing their average molecular weight. The lower average molecular weight makes the polyolefins more susceptible to further cracking in subsequent reactors, allowing for more efficient conversion into valuable hydrocarbons. The presence of strong base or bases such NaOH, KOH or lime in the system helps not only in neutralizing contaminants but also in facilitating the breakdown and transformation of waste into cleaner and more manageable byproducts.

[0089] In one embodiment of the present invention, the initial phase of hydrolysis, known as Stage 1 hydrolysis, can take place within the extruder (252), as illustrated in Figure 2. In some configurations, the PPS (100) may undergo pre-heating in several stages before entering the extruder. This pre-heating can be facilitated through a separate unit dedicated to the storage and heating of the material. During this process, SPS can either be mixed directly with the PPS before it reaches the extruder or injected directly into the feeding or melting section of the extruder.

[0090] Referring to Figure 1, the melted feed, which primarily comprises hydrolyzed PPS (500), SPS (134), and reaction products (mainly chemical salts), is introduced into the cracking stage (140).

[0091] Extruders are essential in the chemical recycling of plastics, offering substantial benefits in the melting and transfer of recycled materials. They provide precise control over temperature and pressure, ensuring uniform melting of the plastics without thermal degradation, which is crucial for preserving the chemical structure necessary for effective recycling. The continuous and consistent operation of extruders in the present invention also enables the controlled and efficient breakdown of polymers into their monomers or other chemical forms, facilitating their reuse in new plastic production. Furthermore, extruders can process various types of plastics and contaminants, making them versatile tools in chemical recycling. Their integration with in-line filtration and reaction systems further improves the purity and quality of the recycled material, making them key to advancing the circular economy in the plastics industry.

[0092] The PPS (500) stream, intended for conversion into end products such as hydrocarbons in the naphtha and / or gasoil boiling point range (144) and hydrocarbon gases, is introduced into a high-temperature reactor operating under moderate pressure. This approach adheres to established industry practices and expert guidelines for converting plastics into desired chemical products and fuel components. In certain cases, residual fractions or heavy oils (152) that are unsuitable for specialty or general chemical applications may be directed to an extruder (252) or a cracking reactor (260), as illustrated in Figure 2. These residual fractions, including waxes collected from the bottom of the distillation towers (1051), are then transferred to the extruder (252) or cracking reactor (260) for additional processing. In some embodiments, these fractions can be used for energy recovery, for example for electricity or heat generation.

[0093] Depending on the composition of the PPS (100) used— such as the presence of PVC, engineering plastics, or organic contaminants— the separated water may contain materials with nitrogen, oxygen, sulfur, and / or chlorine.

[0094] Alternatively, as depicted in Figure 3, the cracking (140) stage can be further optimized using a thermal-chemical platform. For instance, the hydrolyzed PPS (500) stream might undergo established cracking processes to generate fuel gas (146), carbon solids (142), and hydrocarbons within the naphtha and gasoil boiling point ranges (144). Additional thermal-chemical techniques, such as vis-breaking, hydrotreating, hydroprocessing, reforming, hydrocracking, catalytic cracking, gasifying, and pyrolyzing, can be utilized to adjust the boiling point distribution of the resulting hydrocarbon mixture. Although gasifying and pyrolyzing PPS (100) streams have traditionally been challenging, the consistent quality of the output from the second stage (240) separation (130) in these embodiments enhances the effectiveness of these treatments.

[0095] In Figure 4, during the illustrative cracking (140) stage within the thermal-chemical platform, the hydrolyzed PPS (500) is subjected to conditions that facilitate reactions such as thermal cracking (140), catalytic cracking (140), or other established processes. Additionally, any solid products from the plastic that have reacted can also be introduced into the cracking reactor (260).

[0096] In the cracking reactor (260), the hydrolyzed PPS (500) is subjected to high temperatures and moderate pressures, resulting in the conversion of the material into a variety of valuable products. This usually encompasses carbon solids (142) and a blend of hydrocarbons, which are typically emitted as hydrocarbon vapors and gases (148).

[0097] To effectively prevent secondary reactions in the cracker, it is crucial to manage the partial pressures of light olefins and diolefins. These compounds are highly reactive and can lead to unwanted side reactions if their concentrations are too high. Lowering their partial pressures helps minimize these risks. As illustrated in Figures 3&4, steam injection (135) is a strategic approach to achieve this. By introducing steam into the cracker (260), the partial pressures of olefins and light diolefins and other unsaturated hydrocarbons are reduced through dilution. Steam acts as a carrier gas, dispersing these reactive components and decreasing their concentration in the reaction environment. This dilution effect helps in controlling the reaction conditions more precisely and reducing the likelihood of secondary reactions. The use of steam injection not only aids in managing these reactive species but also enhances the overall efficiency of the cracking process. It allows for more stable operation and can improve the yield and quality of the desired products by mitigating the formation of undesirable by-products. The steam (135) compared to PPS can be in the range of 0% to 100%, with optimal conditions typically being between 1% and 50%, and under very optimal conditions, the proportion being between 2% and 30%, with the most effective range for feeds primarily composed of polyolefins being between 5% and 15%.

[0098] In the cracking (140) stage, optimal conditions usually involve higher temperatures and lower pressures than those in the hydrolysis stage (120). The cracking (140) process may also involve the addition of water, nitrogen, CO, CO2, hydrogen, other gases or the mixtures thereof. Different types of equipment can be employed to facilitate the cracking (140) stage.

[0099] Cracking (140) reactions typically occur within a temperature range of approximately 250 °C to 800 °C, with a preferred range of 300 °C to 750 °C, a more preferred range of 350 °C to 700 °C, and an optimal range of 400 °C to 600 °C. The reaction duration usually ranges from about 1 minute to 360 minutes, with a preferred duration of 2 to 240 minutes, a more preferred duration of 3 to 180 minutes, and an optimal duration of 5 to 120 minutes. Different components within the products experience varying times in the cracking reactor (260); for instance, vapors pass through quickly, while liquids remain in the reactor for a longer period.

[0100] The output from the cracking (140) stage consists of two main components: a mixture of hydrocarbon vapor and gases (148) and carbon solids (142). The hydrocarbon vapor and gases (148) include CO2, CO, nitrogen-containing compounds, sulfur-containing compounds, and oil (149) vapor. The carbon solids (142) are similar to high-quality coke. Conditions in the cracking (140) stage are meticulously controlled to ensure the purity of both the carbon solids (142) and the hydrocarbon vapor and gas (148) mixture. Rapid quenching of the hot vapors is crucial to prevent secondary reactions and reduce the formation of carbon char after the vapor exits the cracking reactor (260).

[0101] In an exemplary setup, rapid quenching of vapors can be achieved by directing them into a water-filled drum or by employing multiple quenching stages using thermal fluids and cooling media. Implementing multiple quenching steps can improve the recovery of hydrocarbons in the naphtha and / or gasoil boiling point range (144) from the hydrolyzed PPS (500). Alternatively, vapors with lower boiling points can be quenched using incoming hydrocarbon liquids, which also contributes to energy recovery.

[0102] In thermal-chemical platforms used for the cracking (140) stage, temperatures typically range from about 250 °C to 800 °C, with an optimal range of 300 °C to 750 °C, a more preferred range of 350 °C to 700 °C, and the most ideal range of 400 °C to 600 °C. These temperatures enable the breakdown of PPS (500) into hydrocarbons or the cracking (140) of hydrocarbon molecules into lower molecular weight compounds, which generally occurs at temperatures of 400-650 °C or above. Established methods indicate that hydrocarbon cracking (140) usually occurs at temperatures exceeding 480 °C. The cracking (140) stage may operate at higher temperatures compared to the hydrolysis stage (120), with the second stage (240) reactor pressurized between approximately 0.1 bar and 30 bar, preferably between 0.5 bar and 25 bar, and most ideally between 1 bar and 20 bar in one embodiment. In some configurations, the pressure within the cracking (140) stage reactor may be lower than that in the first stage, tailored to the specific operational requirements of the process.

[0103] An example of the cracking (140) stage is shown in Figure 5. Carbon solids (142) produced by the cracking reactor (260) are first routed to a carbon solids cooler (630) to cool and dissipate residual heat. Once cooled, the carbon solids (142) undergo passivation, such as controlled air dosing, to mitigate or eliminate the risk of self-heating when exposed to air. The passivated carbon is then transferred to carbon storage (540) for future use. The mixture of hydrocarbon vapor and gases (148) from the cracking reactor (260) is directed to a cooler (850) or condenser, which separates it into fuel gas (146) and hydrocarbon oil (149). After separation, the hydrocarbon oil (149) is further divided into components such as liquid hydrocarbons (144) and heavy oil (152) compounds (including wax). Heavy compounds are recycled back to the cracking reactor (260), while the liquid hydrocarbons (144) are isolated.

[0104] While the process outlined in this invention operates within a specified range of parameters, adjustments to factors like temperature and pressure can be made to improve yield and efficiency. These adjustments are illustrated for various types of feedstock. It is essential to recognize that operating parameters can be tailored to accommodate different raw materials or specific process needs, provided that the fundamental principles of the invention are maintained.

[0105] For example, in the case of PPS (100) raw feedstock, the main components are primarily polyolefins, but may also include polyesters, polycarbonates, polyamides, polyurethanes, engineering plastics, PVC, rubbers, paper, organic (food) contaminants, and minerals.

[0106] The balance of these primary components can influence various operational parameters of the processing steps described in this invention. Additionally, the temperature range used during initial reactions and subsequent processing stages can be adjusted to favor the production of specific products, such as light hydrocarbons like circular naphtha (144), thereby enhancing the economic value of the resulting products.

[0107] Various embodiments of the invention have been tested with different types of waste, primarily various streams of plastics, and the data has been compiled to determine the composition and product breakdown for these different plastic waste streams.

[0108] For PPS (100) feedstocks with significant polyolefin content, such as polyethylene and polypropylene, it is beneficial to remove contaminants like polyesters, polycarbonates, polyamides, polyurethanes, engineering plastics, PVC, rubber, paper, and minerals either during the feed preparation (110) stage or beforehand. Methods for contaminant removal are well-established and may include separating contaminants before slurring or using water washing.

[0109] Shredder residue typically consists of about 50% combustible material and 50% noncombustible (inert) material. It may also contain substances like brake fluid, gasoline, engine oil (149), windshield washer fluids, antifreeze (ethylene glycol), FREON™ refrigerants, and occasionally polychlorinated biphenyls (PCBs) from shredding electronics and old appliances with intact capacitors. Additionally, shredder residue can contain heavy metals such as lead, mercury, and cadmium. The moisture content of shredder residue can vary based on whether the shredding process is wet or dry and its exposure to rain during storage. Although shredder residue is generally considered "dry," it can still have up to 15% moisture by weight. Similarly, MSW, tires, and mixed plastics used as feedstock may share characteristics with shredder residue. However, MSW introduces additional considerations due to its varied content, which may include animal by-products. These by-products can undergo premature reactions, such as the hydrolysis of fats and proteins, if temperatures exceed their decomposition thresholds, especially when moisture content is high. Such premature hydrolysis can lead to the formation of stable emulsions that are challenging to break down in later processing stages. In some cases, a two-step decomposition reaction may be used to address the specific content of the feedstock effectively.

[0110] Solvents and Modifications

[0111] To optimize processing efficiency, specific modifications based on the composition of the raw feed may be necessary. For instance, adding an organic solvent to dense hydrocarbon feedstocks— such as plastics, rubber, tires, and foam— can enhance the organic content and improve the yield of usable liquid mixtures. Incorporating acids or alkaline materials can help control pH levels during processing. The solvent can be mixed with PPS (100) and introduced into the extruder (252) or added directly to the melt section of the extruder.

[0112] When the raw feedstock includes plastics, either alone or as part of shredder residue (SR), the hydrocarbon oil (149) produced during the process serves as an effective solvent, often outperforming other known solvents. This allows some of the hydrocarbons produced to be reintroduced into the raw feed or used in earlier-stage reactions. Typically, these hydrocarbons have a boiling range between 50 °C and 400 °C, preferably between 100 °C and 350 °C. The hydrocarbon solvent may be preheated before application to shredder residue, tires, or mixed plastics feedstock. Alternatively, the hydrocarbons can be applied directly to the feedstock, and the mixture heated to temperatures between 100 °C and 350 °C, preferably between 200 °C and 350 °C. Utilizing the final stage oil (149) as a solvent eliminates the recurring costs associated with other solvents and their replenishment. In some embodiments, either the entire range of constituents in the oil (149) or a selected portion is used to dissolve tires, shredder residue, MSW, and / or mixed plastics.

[0113] For example, the hydrocarbon oil (149) from the initial batch can be recirculated back into the tire feedstock. Alternatively, only the final-stage heavy oil (152) product may be redirected in this manner. If only part of the constituents is used, the solvent can be separated into its components during either the hydrocarbon oil (149) finishing step or the first stage of the process. Using hydrocarbon oil (149) as a solvent can enhance the economic viability of the process compared to traditional methods. If the oil (149) is not immediately available for processing the first batch, an alternative solvent may be used initially.

[0114] Effective solvents for processing dense hydrocarbon feedstocks, such as plastics and rubber, include toluene or other so-called aromatic compounds. Other suitable solvents can be identified by experts in the field. During the initial hydrolysis stage for processing tires and mixed plastics, adding extra water can assist in removing chlorine or other halogen-containing materials.

[0115] In certain embodiments, the hydrocarbon vapor and gases (148) produced from the cracking stage (140) mainly consist of hydrocarbon gases, with minor impurities of non-hydrocarbon gases. These hydrocarbon gases include fuel gas (146), while hydrocarbon vapors can be condensed into liquids or oils (149). The fuel gas (146) has a high calorific value and can be reused within the process for heating or generating electricity. Oil (149) typically contains hydrocarbons with carbon chains of 30 or fewer carbon atoms, similar to lighter components in fuel oils (149) like naphtha and / or gasoil (144), making it commercially viable for sale. Heavy oil (152), which includes wax or waxy components, can be redirected to the cracking reactor (140) for further processing.

[0116] The composition of oil (149), naphtha and / or gasoil (144) and heavy oil (152) is influenced by the type of feedstock and the reaction conditions during conversion and finishing steps. These oils may contain paraffins, o-olefins, naphthenes, aromatics, and other components. For instance, oils from high plastic content feedstocks typically has more olefins and di-olefins, while oils from tires often contains aromatics, naphthenes, and sulfur compounds. Olefins can be removed through saturation or other post-treatment techniques known to experts.

[0117] Equipment

[0118] The apparatuses for implementing the processes described can be assembled using standard components familiar to process and chemical engineers. These apparatuses are typically made from materials that can withstand high temperatures and exposure to water while meeting corrosion resistance requirements, with carbon steel used for the main structure and 316L stainless steel or other corrosion-resistant alloys for components that encounter extreme pH conditions. Specialized metals like Hastelloy, titanium, tantalum, and various hardened steels, cladding, surface treatment, coating, etc., may be used for parts requiring enhanced resistance to alkalines, acids or specific conditions, though these are not necessary for the core objectives of the invention.

[0119] Various reactors, tanks, separators, conveyors, and other equipment can be employed, including filters with openings smaller than suspended solid particles, clarifiers, settling chambers, and cyclones. When the size or density difference between solid particles and the fluid is small, centrifugal devices are more effective.

[0120] Handling of Problematic Waste

[0121] The processes described are well-suited for handling challenging waste materials. An advantage is the effective removal of gaseous impurities, such as ammonia, nitrous oxides, carbon monoxide, carbon dioxide, and sulfur-containing gases, during feed preparation (110), downstream feed storage, and hydrolysis (e.g., feed storage (320) as shown in Figure 3). Hydrolysis can generate sulfur-containing gases from sulfur-rich components in PPS (100), particularly from vulcanized rubber. Common sulfur-containing gases include hydrogen sulfide (H2S) and mercaptans (alkyl-sulfur compounds) like methyl mercaptan. Sulfur-rich salts, such as calcium sulfide (CaS), are typically separated in subsequent stages.

[0122] Hydrolysis of chlorinated and / or brominated organics breaks down carbon-halide and oxygen-halide bonds, causing metals and halides to migrate into the water phase. This process is particularly effective for recycling PVC and treating waste containing PCBs and PBDEs.

[0123] PVC, which is about 58% chlorine by weight, can release toxic substances like dioxins when incinerated or processed conventionally. Using water in this process allows hydrogen ions to react with chloride and halogen ions from PVC, resulting in soluble products such as hydrochloric acid. This chemical is relatively harmless, commercially valuable, and commonly used in cleaners and solvents, with minimal contaminants and debris.

Claims

24CLAIMS1. A method for upcycling synthetic and organic waste, comprising:• Preparation of compacted waste plastic as the primary process solid (100),• Conveying the primary process solid (100) into a PPS storage tank (220),• Subjecting the primary process solid (100) to hydrolysis (120) in an extruder (252), either mixed with the secondary process solid (134) or by directly injecting SPS into the feeding section or melt section of the extruder,• Directing the hydrolyzed primary process solid (500) from the extruder (252) to a thermal cracker reactor (260).

2. The method of claim 1, wherein the primary process solid (100) is selected from any type of plastic or rubber waste, including polyolefins or tires.

3. The method of claim 1, wherein the primary process solid (100) is selected from the group consisting of polyethylene, polypropylene, polystyrene, PET, polyester, polycarbonate, PVC, textiles, minerals, biomass, fats, rubber, tires, polyurethane, polyamide, synthetic plastics, natural plastics, or mixtures thereof.

4. The method of claim 1, wherein the secondary process solid (134) is a base or salt, including strong bases such as NaOH, KOH, and lime, salts like calcium carbonate, sodium (bi)carbonate, potassium (bi)carbonate, and alkali metal compounds, alkali earth metal compounds, or transition metal compounds, or the mixtures thereof.

5. The method of claim 1, wherein the hydrolysis (120) temperature of the PPS (100) ranges from 50 °C to 450 °C, with preferred ranges being from 80 °C to 425 °C, more optimal conditions being between 150 °C and 400 °C, and ideally between 300 °C and 350 °C, depending on the starting material.

6. The method of claim 1, wherein the hydrolysis (120) period for the PPS (100) ranges from 0.1 to 60 minutes, with preferred durations being from 0.2 to 10 minutes, more precise intervals being from 0.3 to 5 minutes, and ideally from about 0.5 to 2 minutes.

7. The method of claim 1, wherein the steam injection inside the cracker (260) is between 0-20%, preferably more than 5% and most preferably more than 10% relative to the feedstock.

8. The method of claim 1, wherein the steam, other gases such as nitrogen, CO, CO2, hydrogen or their mixtures thereof (135) compared to PPS is in the range of 0% to 100%, with optimal conditions typically being between 1% and 50%, and under very optimal conditions the proportion being between 2% and 30%, with the most effective range for feeds primarily composed ofpolyolefins being between 5% and 15%.

9. The method of claim 1, wherein the extruder (1032) features a single or twin- screw design.

10. The method of claim 1, wherein the proportion of SPS compared to PPS is in the range of 0% to 60%, with optimal conditions typically being between 0% and 20%, and under very optimal conditions, the proportion being between 0% and 10%, with the most effective range for feeds primarily composed of polyolefins being between 0.1% and 5%.

11. The method of claim 1, wherein the thermal conversion reactor (260) is selected from an auger reactor, batch reactor, extruder, continuous stirred- tank reactor, fluidized bed reactor, or any other reactor type that supports the heating and movement of the solid material.

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