System and method for degassing pyrolytic plastics

Abstract

A method and apparatus for reducing the halogen content of waste plastic material is described, comprising: heating a halogen-containing molten plastic mass in a first heating zone to a temperature in the range of about 220°C to about 350°C to produce a liquid and gaseous mixture, the gaseous mixture dispersed in the liquid phase; passing the dispersed gaseous mixture to a degassing chamber via an outlet of the first heating zone; separating the dispersed gaseous phase from the liquid phase in the degassing chamber to produce a primarily gaseous material mass containing the halogen-containing compound and a liquid plastic material mass; venting at least a portion of the gaseous phase from the degassing chamber via a gas outlet of the degassing chamber; and passing the liquid phase material to one or more subsequent heating zones via a liquid outlet of the degassing chamber to heat the liquid phase to a temperature above the pyrolysis temperature.

Description

Detailed Description of the Invention

[0001] [Field of the Invention]

[0001] The present invention generally relates to methods and apparatus for treating waste plastics by pyrolysis, and the products obtained by these methods and apparatus. More particularly, the present invention relates to methods and apparatus for heating waste plastics to cracking temperatures while removing potential product contaminants such as halogens, particularly chlorine. Furthermore, the present invention relates to a system for separating gases, liquids, and optionally solid particles in molten plastic materials. Furthermore, the present invention relates to methods and systems for separating products obtained from cracking long-chain hydrocarbons, and in particular, to methods and systems for treating plastics and polyolefins by cracking.

[0002] [Background of the invention]

[0002] Modern society generates large amounts of waste plastic. Although plastic recycling is becoming increasingly efficient and effective, the reality is that much of the waste plastic cannot be effectively or efficiently recycled and is instead disposed of in landfills, where it can take years to decompose, or it can be lost to the environment, where it can cause damage to ecosystems.

[0003]

[0003] However, plastic materials are made from essentially useful compounds that can be used as is and / or converted for (re)use. For example, fuels such as diesel can be derived from waste plastics, or waste plastics can be converted into raw materials suitable for the synthesis of new materials, such as new plastics, other hydrocarbon materials, etc. Materials recovered from waste plastics can be useful to at least partially replace hydrocarbons more traditionally obtained from natural gas or mineral oil.

[0004]

[0004] The output of plastic-to-chemical plants typically includes light hydrocarbons (LHC), heavy hydrocarbons (HHC), charcoal, and non-condensables (gases). Currently, LHC, HHC, or a mixture thereof are the most desired products, but this is market dependent.

[0005]

[0005] The LHC and HHC fractions are required by the industry to meet certain chemical and physical specifications, such as vapor pressure, initial boiling point, final boiling point, flash point, viscosity, cloud point, and cold filter plugging point. While different qualities may be desired by different customers or end uses, it is important for plastics-to-chemicals plants to produce products of consistent quality. The final quality of the product fractions is controlled by distillation columns, such as those commonly used and well-known in the petrochemical industry. It is desirable for the light and heavy hydrocarbon fractions to be relatively pure so that they do not contain significant amounts of high-boiling compounds. Such high-boiling compounds can increase the cold filter plugging point and cloud point, and are often unacceptable to purchasers of pyrolysis oil.

[0006]

[0006] In plastics-to-chemicals plants, the input is raw plastics, which may consist largely of polyethylene and polypropylene from domestic sources. These plastics, made from very long chain hydrocarbons, are then cracked into shorter chains, forming a wide range of molecules with varying chain lengths. These mixtures can be distilled into various fractions, as is known, determined by temperature.

[0007]

[0007] A known process in the art for converting waste plastics, among others, into diesel, is the thermochemical decomposition process of pyrolysis. Pyrolysis is the thermal decomposition of waste plastics in an inert atmosphere. In effect, the long polymer chains of the plastic polymers are cracked by heating, yielding shorter hydrocarbon chains that are generally more useful as products.

[0008]

[0008] Pyrolysis is the preferred method for carrying out the thermochemical decomposition of waste plastic materials. Various attempts have been made to provide industrially cost-effective pyrolysis of waste plastics.

[0009]

[0009] Industrially useful results have been obtained using the techniques discussed in patent publications U.S. Patent Application Publication No. 2018 / 0010050 and WO 2021053139, the contents of which are incorporated herein by reference.

[0010]

[0010] U.S. Patent Application Publication No. 2018 / 0010050 discusses a method for recovering hydrocarbons from plastic waste, particularly polyolefin-rich waste, by pyrolysis without the use of a catalyst. The process involves melting the plastic waste in two heating devices and mixing a stream from a cracking reactor with the inflowing molten plastic waste from the first heating device. The heated and molten plastic is sent to the cracking reactor, where the plastic material is cracked. The cracked material is then distilled into diesel and low-boiling substances.

[0011]

[0011] WO 2021 / 053139, which offers some advancements over U.S. Patent Application Publication No. 2018 / 0010050, discusses, among other things, a method for cracking long-chain hydrocarbons from plastic-containing waste, the method including the steps of providing a material containing long-chain hydrocarbons, heating a specific volume of the material containing long-chain hydrocarbons to a cracking temperature at which the hydrocarbon chains of the material begin to crack into shorter chains, and, for the specific volume having a temperature above the cracking temperature, exposing the specific volume to heat not more than 50°C above the temperature of the specific volume. After the specific volume of material has been exposed to heat, WO 2021 / 053139 sends the partially cracked molten plastic stream to a gas-liquid separation structure. The separation structure, also referred to as a reactor, includes a separation zone including a gas-liquid phase boundary and a settling zone where heavy hydrocarbons and / or solid carbon, and potentially other solids such as aluminum, sand, and soil, accumulate.

[0012] While good results have been achieved based on the foregoing techniques, there is room for further improvement; for example, it would be useful to provide a system and process that is more versatile than systems previously attempted.

[0013]

[0013] EP 2876146 discusses tested technology for recovering hydrocarbons from polyolefin plastic recycle by pyrolytic cracking, which process includes the steps of introducing the plastic recycle into a mixing vessel under inert gas and mixing with diesel oil, removing water vapor in a first heating zone, removing acid gases in a second heating zone, liquefying the not yet melted plastic recycle in a third heating zone, cracking the plastic recycle in a cracking reactor at about 400 degrees Celsius, partially condensing to prevent the release of paraffins, and fractionating the cracked product.

[0014] The present invention has the general object of improving the overall system of such pyrolysis processes and apparatus, and the improvements can preferably include one or more of the following aspects:

[0015] In one aspect, it is an object of the present invention to provide alternatives, preferably improvements, to pyrolysis processes and apparatuses that can help reduce the halogen, preferably chlorine, content of waste plastics before or during pyrolysis.

[0016] It is also an object of the present invention to provide an improved method for cracking long chain hydrocarbons.

[0017] In embodiments of the present invention, it may be useful to achieve better control of product quality and yield improvements of the product fractions sent to distillation, as well as better control of which fractions are ultimately distilled. For example, it may be desirable to be able to handle a wide range of feedstocks, including halogen-containing plastics such as PVC, while producing a relatively pure hydrocarbon product with little or no residual halogen content (e.g., Cl). For example, it may be an objective to achieve a more commercially useful ratio of noncondensables, light hydrocarbon fractions, and heavy hydrocarbon fractions of the product stream, while simultaneously minimizing the halogen content of such products.

[0018] In one aspect of the present invention, it may be desirable to improve the reliability of the process.

[0019] In one aspect of the present invention, it may be desirable to improve or limit system downtime.

[0020] A non-limiting object of the present invention is to provide an efficient, versatile, and / or robust process and apparatus for converting waste plastics into useful product streams, such as non-condensable gases, light hydrocarbons, heavy hydrocarbons, paraffins, bitumen, tar, and other similarly derivable fractions. In this regard, the present invention may, for example, address one or more of the problems discussed above, or at least provide a useful option in the art.

[0021]

[0021] Attempts have been made in the past to achieve effective pyrolysis of waste plastics.

[0022]

[0022] Patent publication WO 11077419, which refers to a process for treating waste plastics, discusses an example in which plastics are melted and then pyrolyzed in an oxygen-free atmosphere in a jacket-heated pyrolysis vessel to form pyrolysis gases. The pyrolysis gases flow upward through a pipe directly connecting the pyrolysis chamber to the contactor vessel and contact the plates of the contactor vessel, thereby condensing some of the long-chain gas components. The condensed liquid flows downward through the same pipe and directly back into the pyrolysis zone. The condensed liquid is then reheated in the pyrolysis zone and further pyrolyzed. The short-chain gas components exit the contactor in gaseous form and are directed to distillation.

[0023]

[0023] WO 11077419 explains that when the batch ends, an increase in the load on the pyrolysis chamber agitator indicates that char drying is occurring and the process is complete. The pyrolysis chamber is then purged by reversing the operation of the double-helix agitator blade to remove the char, and nitrogen is pumped upward through the contactor and discharged directly to the thermal oxidizer to wash away any remaining hydrocarbons; during this stage, the pyrolysis vessel and contactor are isolated from the rest of the system. Such processes and systems can be problematic and suboptimal. For example, including an agitator in the pyrolysis chamber and directly jacketing and heating the pyrolysis chamber are necessary, albeit complicated. This system also uses a specific type of jacket-cooled contactor with a sloped, open-ended cooling contactor baffle plate to return condensed hydrocarbons from the contactor directly to the pyrolysis chamber through the same tubes through which the pyrolysis gases entered the contactor. This can be complicated; the pyrolysis process results in batch completion with a dry char (carbon) product and associated purging, which results in extended downtime of the pyrolysis reactor.

[0024] Previous attempts have involved placing a partial condenser directly on top of the pyrolysis vessel to return heavy hydrocarbons for further cracking. Some of these attempts have been found to be less than optimal in versatility, robustness, and efficiency. Without being bound by theory, technical investigations have demonstrated that returning condensed liquid from the partial condenser directly to the pyrolysis reactor vessel can result in temperature mismatches and heat losses in the pyrolysis zone, requiring complex heat input in the pyrolysis zone with the potential for hot spots, carbonization, complex mixing, and / or energy losses. It would be desirable to provide a process and system that is less susceptible to such drawbacks.

[0025] Another example is discussed in Swiss Patent Application Publication No. 708681, which refers to a process for recovering hydrocarbons from polyolefin plastic recycle by pyrolytic cracking. The plastic recycle is introduced into a mixing vessel under inert gas and subjected to the following steps: mixing with diesel oil, removing steam in a first heating zone, removing acid gases in a second heating zone, liquefying the not-yet-melted plastic recycle in a third heating zone, cracking the plastic recycle in a cracking reactor at about 400°C, partially condensing to prevent the release of paraffins, and fractionating the cracked product.

[0026] The partial condenser in Swiss Patent Application Publication No. 708681 is separate and remote from the pyrolysis reactor, and a connecting pipe leads the pyrolyzed gases from the pyrolysis reactor to the partial condenser. The partial condenser is adjusted so that heavy hydrocarbons not of the desired product characteristics condense and are returned via a separate pipe to the third heating zone, where these pyrolyzed gases can be further cracked. The additional cracking loop reduces excessive heavy hydrocarbons in the product.

[0027]

[0027] Attempts to implement concepts related to those disclosed in CH 708681 A1 have been found to be feasible to produce, but have shown some instability and inefficiency in the pyrolysis, for example requiring complex heating in the pyrolysis zone. Furthermore, the system of CH 708681 A1 can be complicated to implement due to the pressure difference between the partial condenser and the heating zone to which the heavy hydrocarbons are returned.

[0028]

[0028] Other attempts have included U.S. Patent No. 10,160,920, which describes a continuous cracking process for thermally cracking hydrocarbon feedstocks in cascade cracking units; U.S. Patent Application Publication No. 2007227874, which discusses a method for recovering fractionated hydrocarbons from recycled plastics; and U.S. Patent No. 5,580,443, which discusses a process for thermally cracking low-quality feedstocks containing a significant proportion of heavy fractions, such as high-boiling fractions.

[0029]

[0029] In US Patent Application Publication No. 2018 / 0010050, purified and pre-sorted polyolefin-rich waste materials are used as raw materials. Despite being sorted, these plastic materials may still contain interfering substances such as chlorine- and / or sulfur-containing compounds, rubber, metal, sand, etc., which are said to be removed at a later point in the process.

[0030] The raw material mixture is fed into a compressor, in which the plastic mixture is homogenized and heated essentially by friction. The material in the compressor is heated to 120-150 degrees Celsius in the compressor, and water vapor is removed under vacuum.

[0031] The material is then conveyed to an extruder where it is heated to approximately 250-300 degrees Celsius. The sulfur- and chlorine-containing plastic fractions are destroyed, and HCl and H2S are exhausted from the extruder via a vacuum pump. Acidic contaminants are preferably neutralized in a scrubber and disposed of.

[0032] The extruder then sends the material to a heat exchanger (tube and shell) where the recyclable plastic material is further heated to about 380 degrees Celsius to fully melt. In a second subsequent heat exchanger, the plastic melt is heated to 400 degrees Celsius and then sent to a cracking reactor.

[0033]

[0033] International Publication No. 2021 / 053139, which presents many advancements relative to U.S. Patent Application Publication No. 2018 / 0010050, also discusses degassing from an extruder.

[0034] WO 2022 / 147473 discusses a method for pyrolyzing a mixed plastic waste stream to produce an oil product with reduced chloride content. In one embodiment, mixed plastic waste from the end of a mechanical recycling facility (MRF), which would normally be sent to a landfill, is used as the pyrolysis feedstock. The mixed feed stream is added to a melt reactor, which is said to function as a dechlorination reactor and can operate at temperatures between 200°C and about 350°C, or between 280°C and 320°C. In the melt reactor, polyvinyl chloride is pyrolyzed primarily by a "thaw" reaction, where chloride molecules are easily removed by pyrolytic free radical reactions, extracting hydrogen at nearby sites to form hydrogen chloride. The temperature of the melt reactor is said to melt the plastic components, producing hydrogen chloride. The resulting gas containing hydrogen chloride is sent to combustion, and the liquid is sent directly to the pyrolysis chamber. Improvements and alternatives to such systems are desirable.

[0035] All references, including any patents or patent applications, cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art.

[0036] [overview]

[0036] The invention is defined in the independent claims, while further aspects of the invention are set out in the dependent claims, the drawings and the following description.

[0037] In accordance with an aspect of the present invention, there is provided a method for heating a halogen-containing plastic material to pyrolysis temperatures, comprising the steps of: A step of heating and melting a halogen-containing solid plastic raw material, for example, waste plastic particles or waste plastic pellets containing polyvinyl chloride, at a temperature in the range of about 200°C to about 325°C, preferably about 210°C to about 300°C, more preferably about 220°C to about 280°C, and most preferably about 260°C; removing water vapor and other gases generated during the fluidizing and heating steps; delivering molten plastic material to a first heating zone; further heating the molten plastic mass in the first heating zone to a higher temperature in the range of about 220°C to about 350°C, more preferably about 280°C to about 340°C, more preferably about 300°C to about 330°C, and most preferably about 330°C to generate a liquid phase and a gas phase, which are mixed in the first heating zone; allowing the liquid and gas phases to separate to result in a body of material in a predominantly gas phase comprising at least halogen-containing compounds (and optionally additional non-halogen contaminants in the gas phase), preferably chlorine, and a body of plastic material in a liquid phase; removing at least a portion of the gas phase; Passing the liquid phase material through one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature; and Preferably, sending the output liquid phase of the heating zone at said pyrolysis temperature to a pyrolysis reactor and / or a distillation apparatus. A method is provided, comprising:

[0038] In one aspect of the present invention, there is provided an apparatus for heating a halogen-containing plastic material to pyrolysis temperatures, the device comprising: a heat-melting compartment arranged to heat-melt waste plastic particles or waste plastic pellets containing halogen-containing solid plastic raw materials, optionally or alternatively bio-organic raw materials, for example, polyvinyl chloride, to a temperature in the range of about 200°C to about 325°C, the heat-melting compartment being provided with an inlet for the plastic raw materials, at least one gas outlet for releasing gas evolved from the plastic raw materials during heat-melting, and an outlet for the molten plastic material; a first heating zone configured to receive molten plastic material from the heating and melting section and further configured to heat the molten plastic material to a temperature in the range of about 220°C to about 350°C to produce a liquid phase and a gas phase, the liquid phase and the gas phase being mixed in the first heating zone; a degassing zone provided with an inlet arranged to receive the mixed liquid and gas phases from the first heating zone, the degassing zone being arranged to allow separation of the mixed liquid and gas phases into a body of mainly gas phase material and a body of liquid phase plastic material, the degassing zone further comprising a gas outlet for discharging the gas phase and a liquid outlet for discharging the liquid phase, preferably the gas outlet being higher than the liquid outlet; at least one subsequent heating zone arranged to receive said liquid phase from the degassing zone liquid outlet, the heating zone arranged to heat said liquid phase to a higher temperature, preferably a pyrolysis temperature; An apparatus is provided comprising:

[0039] In one aspect of the present invention, there is provided a method for reducing the halogen, preferably chlorine, content of waste plastic material, comprising the steps of: heating the halogen-containing molten plastic mass in the first heating zone to a temperature of about 220°C to about 350°C, more preferably about 280°C to about 340°C, more preferably about 300°C to about 330°C, and most preferably about 330°C to produce a mass of a mixed liquid phase and a gas phase, wherein the gas phase is dispersed in the liquid phase; sending the mixture of dispersed gas and liquid through an outlet of the first heating zone to a degassing chamber; allowing the gas phase to separate from the liquid phase in a degassing chamber to result in a body of material in a primarily gas phase comprising a halogen-containing compound, preferably comprising hydrogen chloride, and a body of plastic material in a liquid phase; Releasing at least a portion of the gas phase from the degassing chamber through a gas outlet of the degassing chamber; and Passing the liquid phase material through a liquid outlet of the degassing chamber to one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature. A method is provided, comprising:

[0040] A method for reducing the halogen, preferably chlorine, content of waste plastic material, comprising the steps of:

[0041] heating the halogen-containing molten plastic mass in the first heating zone to a temperature of about 220°C to about 350°C, more preferably about 280°C to about 340°C, more preferably about 300°C to about 330°C, and most preferably about 330°C to produce a mass of a mixed liquid phase and a gas phase, wherein the gas phase is dispersed in the liquid phase;

[0042] sending the mixture of dispersed gas and liquid through an outlet of the first heating zone to a degassing chamber;

[0043] allowing the gas phase to separate from the liquid phase in a degassing chamber to result in a body of material in a primarily gas phase comprising a halogen-containing compound, preferably comprising hydrogen chloride, and a body of plastic material in a liquid phase;

[0044] Releasing at least a portion of the gas phase from the degassing chamber through a gas outlet of the degassing chamber; and

[0045] Passing the liquid phase material through a liquid outlet of the degassing chamber to one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature. A method comprising:

[0041]

[0046] In one aspect of the present invention, there is provided a method for reducing the halogen, preferably chlorine, content of waste plastic material, comprising the steps of: heating the halogen-containing molten plastic mass in the first heating zone to a temperature of about 220°C to about 350°C, more preferably about 280°C to about 340°C, more preferably about 300°C to about 330°C, and most preferably about 330°C to produce a mass of a mixed liquid phase and a gas phase, wherein the gas phase is dispersed in the liquid phase; sending the mixture of dispersed gas and liquid through an outlet of the first heating zone to a degassing chamber; allowing the gas phase to separate from the liquid phase in a degassing chamber to result in a body of material in a primarily gas phase comprising a halogen-containing compound, preferably comprising hydrogen chloride, and a body of plastic material in a liquid phase; Releasing at least a portion of the gas phase from the degassing chamber through a gas outlet of the degassing chamber; and Passing the liquid phase material through a liquid outlet of the degassing chamber to one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature. A method is provided, comprising:

[0042]

[0047] In one aspect of the invention, there is provided an apparatus for heating a halogen-containing plastic material to pyrolysis temperatures, the device comprising: a first heating zone configured to receive molten plastic material and increase the temperature of the molten plastic material to a temperature in the range of about 220°C to about 350°C to produce a liquid phase and a gas phase, the liquid phase and the gas phase being mixed in the first heating zone; a degassing zone provided with an inlet arranged to receive the mixed liquid and gas phases from the first heating zone, the degassing zone being arranged to allow the mixed liquid and gas phases to separate, preferably under gravity, into a body of predominantly gaseous material and a body of predominantly liquid plastic material, the degassing zone further comprising a gas outlet for discharging the separated gas phase and a liquid outlet for discharging the separated liquid phase, preferably the gas outlet being positioned higher than the liquid outlet; at least one subsequent heating zone positioned to receive said liquid phase from the degassing zone liquid outlet, said at least one subsequent heating zone positioned to heat said liquid phase to a higher temperature, preferably a pyrolysis temperature; An apparatus is provided comprising:

[0043]

[0048] It is a preferred feature that the dispersed gas is separated from the molten plastic liquid in a settling zone, i.e., in a volume where the dispersed gas has a residence time that allows the dispersed gas bubbles to rise from the liquid, preferably coalesce, thereby forming gaseous bodies above the liquid, which can then be selectively released from a degassing zone.

[0044]

[0049] In embodiments of the present invention, the liquid phase flows continuously through the degassing zone from the inlet to the liquid outlet. That is, the liquid always flows in the direction from the inlet to the liquid outlet. The residence time of the liquid volume in the degassing zone is determined by the distance from the inlet to the liquid outlet and the velocity of the liquid flow. Continuous flow combined with degassing is believed to be advantageous in supporting a continuous pyrolysis process that is less susceptible to batch processing problems.

[0045]

[0050] Without wishing to be bound by theory, it is believed that by applying the temperatures discussed, the first heating zone tends to pyrolyze plastics such as PVC more thoroughly and result in less pyrolysis for PE or PP. Thus, the gases in the degassing zone tend to contain a high proportion of chlorine-containing compounds, and the first heating zone, coupled with degassing, can provide a convenient removal step for halogenated materials prior to further processing, pyrolysis, of the PE and PP plastics to form more useful raw material components.

[0046]

[0051] It is a preferred feature of the process to provide a continuous plastics processing process, e.g., a continuous throughput first heating zone and a continuous throughput degassing zone, as opposed to batch-type handling. Continuous processing techniques are believed to offer many advantages over batch-type processing, which necessarily requires temporary shutdown of the process (or modules within the process).

[0047]

[0052] For example, the first heating zone may be provided as a tube-and-shell heat exchanger whereby the molten plastic material is heated during its transition through the tube-and-shell heat exchanger, and the molten plastic material is passed through a tube.

[0048]

[0053] For example, a mixture of dispersed gas in molten liquid plastic can be sent as a continuous flow through a degassing zone having a length in the direction of flow. The residence time preferably allows dispersed gas bubbles to rise from the liquid before the liquid phase material proceeds to one or more subsequent heated zones for further pyrolysis. Separation of the mixed liquid and gas phases preferably occurs under gravity, with the gas phase rising from the liquid phase due to density differences.

[0049]

[0054] The residence time of the dispersed gas and molten plastic liquid can be achieved by controlling the rate of material flow through the settling zone (i.e., from the liquid inlet to the liquid outlet) in combination with the length of the settling zone in the direction of flow and the height of the liquid outlet in the degassing zone. For example, the flow rate and length of the degassing zone can be controlled to allow gas bubbles to rise above the level of the liquid outlet before the liquid exits the degassing zone through the liquid outlet.

[0050]

[0055] Preferably, the degassing zone comprises a degassing vessel separate from the heating zone, for example a separate vessel intermediate the first and subsequent heating zones. Preferably, the degassing vessel is a dome-shaped chamber forming a degassing dome.

[0051]

[0056] 40. The method of claim 39, wherein when the degassing zone comprises a degassing chamber, the degassing chamber is vertically elongated with a height, the chamber is provided with a liquid inlet, and the liquid outlet is positioned lower in the height of the chamber than the gas outlet, and the method further comprises the step of passing the mixture of dispersed gas and liquid through the outlet of the first heating zone to the liquid inlet of the degassing chamber.

[0052]

[0057] The degassing chamber is vertically elongated with a height, and is provided with a liquid inlet, the liquid outlet being positioned lower in the chamber height than the gas outlet. The method further includes sending the mixed mass of dispersed gas and liquid to the liquid inlet of the degassing chamber through the outlet of the first heated zone. In this case, the liquid level can be maintained between the gas outlet and the liquid outlet, allowing for consistent removal of gas and liquid phase. The liquid level is determined by the rate of gas production by pyrolysis combined with the downstream pressure in the system, where downstream refers to the backpressure from the downstream liquid pyrolysis section. Since the gas contains halogen materials, it is desirable that only a minimal level or no gas phase is removed through the liquid outlet. A minimal level of liquid phase material is removed through the gas outlet, and the gas phase is preferably saturated, and condensation of the liquid may occur due to temperature or pressure changes in the gas outlet and downstream thereof. In a preferred embodiment, the gas outlet and associated piping or other elements can be heated to minimize or avoid condensation of the gas phase. Such heating can be in the form of electric tracing, a thermal oil jacket, or the like. Heating can also be used for hot standby and / or start-up modes.

[0053]

[0058] Alternatively, the degassing chamber is preferably vertically elongated, with the liquid outlet being located in the lower half of the height of the chamber and the gas outlet being located in the upper half of the height of the chamber.

[0054]

[0059] Preferably, the gas outlet is positioned in the upper half of the degassing vessel, preferably in the top of the degassing vessel.

[0055]

[0060] The degassing vessel is preferably elongated and arranged at a vertical height, the height of which provides a tolerance buffer to allow for some fluctuations in the liquid level within the degassing vessel.

[0056]

[0061] In that regard, it is advantageous to control the liquid level in the degassing chamber, such as by determining the liquid level and adjusting the rate of gas release from the gas outlet to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid inlet and liquid outlet. The gas release preferably coincides with the release of pressure in the gas phase volume of the degassing zone, allowing the liquid level to rise.

[0057]

[0062] Additionally or alternatively, the liquid level in the degassing chamber can be adjusted by controlling the rate of liquid input and / or output to and from the degassing chamber to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid inlet and liquid outlet.

[0058]

[0063] Preferably, the degassing zone is equipped with liquid level monitoring sensors, preferably radar sensors, temperature sensors and / or gamma ray sensors, one, several or all of which sensors may provide a convenient and reliable determination of the liquid level in the degassing zone, preferably the degassing vessel.

[0059]

[0064] The temperature measurement level sensor device may comprise a vertically arranged rod equipped with multiple temperature measurement sensors. The multi-point temperature measurement device is installed in the degassing vessel, and the liquid level can be assessed based on the temperature difference between adjacent sensors on the rod, e.g., a difference of 3°C to 6°C between the gas and liquid phases.

[0060]

[0065] A gamma radiation source level measurement device can be installed externally and the liquid level determined based on detecting whether gamma radiation is blocked by the presence of liquid. Radioactive level measurement has been found to provide accurate liquid level measurement regardless of dynamic processes and conditions in the degassing zone, including foaming and potential fouling. Notably, radioactive level measurement does not require an internal probe or other internal sensor.

[0061]

[0066] A radar measurement device, preferably a guided wave radar measurement device, may be provided. The guided wave radar measurement device is installed inside the separation vessel 12. A guided wave radar level transmitter is installed on top of the degassing vessel. The guided wave radar measurement device can provide a wide operating range with good reliability. In particular, rod-type guided wave radar is suitable for operation in foaming liquids, and the measurement device operates independently of noise, pressure, temperature, and density fluctuations. Furthermore, contamination of the guided wave radar probe or the inner surface of the separation vessel has only a minimal effect on measurement accuracy.

[0062]

[0067] If the liquid level in the degassing zone rises suddenly or undesirably, this can be counteracted by injecting an inert gas, such as nitrogen gas, preferably a volume of gas into the degassing zone, which can be implemented to increase the pressure and lower the liquid level.

[0063]

[0068] The passage of molten plastics for pyrolysis as a continuous process is advantageously achieved by arranging the heating and degassing zones in series, preferably so that units of plastic material entering the process flow continuously through the process, at least until they exit the final pyrolysis chamber, separation vessel, or distillation process, and are preferably not held in vats or batchwise processing steps.

[0064]

[0069] Preferably, the heating zones are arranged in series, with at least one downstream heating zone positioned higher than an upstream heating zone.

[0065]

[0070] To provide good separation of gas from liquid, the liquid and gas mixture is preferably not agitated by a mechanical agitator in the settling or degassing zone.

[0066]

[0071] The degassing zone or zones are preferably not heated or are only heated to the maximum extent possible to maintain the temperature of the molten liquid mass. Preferably, the temperature of the degassing zone immediately downstream of the first heated zone is controlled to a maximum of about 350°C, preferably a maximum of 325°C.

[0067]

[0072] Separation of the mixed liquid and gas phases of the first heating zone preferably takes place mainly downstream of the first said heating zone, preferably before any subsequent heating zones.

[0068]

[0073] Once the liquid material leaves the degassing zone, it is further heated to a higher temperature in one or more subsequent heating zones to a pyrolysis temperature, preferably in the range of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being sent as the output liquid phase of the heating zone to a pyrolysis reactor and / or distillation apparatus. A final heating zone is preferably provided, which heats the molten plastic liquid to a temperature in the range of about 360°C to about 550°C, preferably about 390°C to about 450°C.

[0069]

[0074] Preferably, one or more subsequent heating zones are also heat exchangers, preferably tube-and-shell heat exchangers, which can advantageously help provide a continuous process for plastics processing, as opposed to batch processing.

[0070]

[0075] Separation of the mixed liquid and gas phases of the first heating zone preferably takes place mainly downstream of the first said heating zone, preferably before any subsequent heating zones, although further degassing zones may be provided between subsequent heating zones, each degassing zone preferably being the same as or similar to the first degassing zone.

[0071]

[0076] For example, it may be preferable to provide two, three, four, or more heating zones. To remove halogen-containing gases, a degassing zone is preferably provided between the first and second heating zones. Furthermore, more degassing zones can be provided between other heating zones or even between all heating zones, and when additional heating zones are provided, for example, a degassing zone can be provided between heating zones 2 and 3 and / or between heating zones 3 and 4.

[0072]

[0077] According to any of the preceding claims, it is preferred that an extruder is provided and that the heating and melting of the halogen-containing solid plastic raw material takes place in the extruder.

[0073]

[0078] The extruder may preferably be provided with a compression section, optionally including a heating section such as a thermal oil heating section or an electric heating section, and an expansion section downstream of the compression section, the compression section being arranged to compress and heat the solid plastic raw material, the expansion section being arranged to allow the compressed plastic material to expand and release gas, preferably air and water vapor, from the plastic material, and the extruder being provided with a gas outlet communicating with the expansion section, whereby gas can be removed from the expansion section.

[0074]

[0079] Preferably, the extruder applies compression and heat to the plastic material following an expansion section.

[0075]

[0080] Preferably, the step of heating and melting the halogen-containing solid plastic raw material to make it liquid and optionally removing water comprises: compressing and heating the plastic raw material to a temperature above 100°C, preferably in the range of about 200°C to about 320°C; thereafter reducing the pressure in at least one expansion zone, preferably a plurality of expansion zones, to release gas, preferably at least air and water vapor, and optionally further contaminants such as biological organic matter; removing at least a portion of the released gas from the extruder; and The remaining plastic material is then compressed and heated to a temperature of approximately 200°C to approximately 320°C. Includes.

[0076]

[0081] The first heating zone is preferably fed by an extruder, such as the extruders discussed above.

[0077]

[0082] A negative pressure can be applied to the gas outlet of the degassing zone to aid in the removal of gas phase materials, where reference to negative pressure refers to a pressure lower than the pressure of the degassing zone.

[0078]

[0083] Chlorine is likely the most commonly found halogen in plastic waste streams, however, due to the prevalence of PVC plastics in domestic use, other halogen and non-halogen contaminants may alternatively or simultaneously be removed. The halogens removed may be selected from the group consisting of chlorine, bromine, fluorine, and mixtures thereof, and preferably the halogen comprises chlorine.

[0079]

[0084] The removed halogen (chlorine)-containing gas can preferably be treated. For example, the gas phase material containing halogen-containing compounds such as HCl can be sent to a scrubber, preferably an alkaline scrubber, more preferably a caustic scrubber.

[0080]

[0085] The waste plastic feedstock for the present invention may preferably comprise polyethylene and / or polypropylene plastics. Preferably, the sum of polyethylene and polypropylene in the feedstock is at least 50% by weight of the weight of the feedstock, more preferably at least 60% by weight, even more preferably at least 75% by weight, and most preferably at least 90% by weight. These materials represent the majority of domestic plastic waste and can be processed by pyrolysis. The preferred plastics for the feedstock are polyethylene or polypropylene.

[0081]

[0086] The feedstock used in any of the embodiments may include polyvinyl chloride plastic. Preferably, the solid plastic feedstock includes polyvinyl chloride plastic, preferably more than 1% by weight, more preferably more than 5% by weight, or the feedstock includes less than 5% by weight, more preferably less than 1% by weight, of polyvinyl chloride plastic.

[0082]

[0087] The solid plastic feedstock may contain polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight, or the feedstock contains less than 4% by weight, more preferably less than 3% by weight, polyethylene terephthalate plastic.

[0083]

[0088] 10. The method of any preceding claim, wherein the solid plastic feedstock comprises polystyrene plastic, preferably more than 1 wt. %, more preferably more than 5 wt. % polystyrene plastic, or the feedstock comprises less than 20 wt. %, more preferably less than 5 wt. % polystyrene plastic.

[0084]

[0089] The pyrolysis temperature may vary within a limited range depending on factors such as the composition of the feedstock and the operating pressure; preferably, the plastic material is heated to a pyrolysis temperature of 360°C or higher, about 390°C or higher, more preferably about 400°C or higher, up to about 450°C, although higher temperatures up to about 500°C or about 550°C may also be implemented. Pyrolysis of plastics may begin as early as about 360°C, and such temperatures may also be considered. However, pyrolysis is more pronounced above about 390°C, which may enable a more economically attractive process.

[0085]

[0090] As used herein, the term "pyrolysis zone" refers to a zone in which the material being treated by a process or system (e.g., waste plastics or derivatives thereof generated by pyrolysis in the process or system) is at pyrolysis temperatures, e.g., temperatures of 360°C or higher, more preferably temperatures of 390°C or higher, and even more preferably temperatures of 400°C or higher. A pyrolysis zone is preferably a zone in a process or system in which the material being treated is at a temperature of about 360°C to about 550°C, more preferably about 390°C to about 500°C, and even more preferably about 400°C to about 500°C. Processes and systems may include pyrolysis zones of different activity. For example, there may be a primary pyrolysis zone, preferably at a temperature above 390°C, where the majority of pyrolysis occurs, and a secondary pyrolysis zone, where the temperature is above 360°C but below 390°C. A pyrolysis zone is a zone in a process, system, or apparatus in which pyrolysis occurs or where pyrolysis conditions are created.

[0086]

[0091] Pyrolysis, as is commonly understood, is carried out in the absence of oxygen, most preferably under an inert atmosphere. Nitrogen gas can form the inert atmosphere. Prior to start-up, the system may be purged with nitrogen gas to form at least an initial inert atmosphere.

[0087]

[0092] The gas phase may preferably consist of pyrolysis gases substantially free of oxygen, optionally containing nitrogen.

[0088]

[0093] The operating pressure of the cracked gas and cracking liquid separator vessels is preferably above ambient to ensure that ambient air does not enter the system. The pressure can be between 1 bar (absolute) and 5 bar (absolute), between 1 bar (absolute) and 3 bar (absolute), between 1 bar (absolute) and 2 bar (absolute), or between 1 bar (absolute) and 1.5 bar (absolute), or between 1 bar (absolute) and 1.05 bar (absolute). This is a lower pressure than exists in the degassing zone, which operates at a higher pressure.

[0089]

[0094] The present invention preferably produces one or more hydrocarbon products, preferably including one or more of butane, propane, kerosene, diesel, fuel oil; light distillates such as LPG, gasoline, naphtha, or mixtures thereof; medium distillates such as kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof. The hydrocarbon products may be saturated, unsaturated, linear, cyclic, or aromatic. Additional products may include non-condensable gases including methane, ethane, ethene, and / or other small molecules. The products may be a source of feedstock for steam crackers in the production of plastics.

[0090]

[0095] The terms "noncondensables" or "noncondensable gases," variously referred to, refer to hydrocarbon fractions that are too volatile to condense in the distillation section and that preferably exit the process as gases. Generally, noncondensable hydrocarbons in a thermal cracking process are considered to have from about 1 to about 7 carbon atoms. Noncondensables can include saturated, unsaturated, linear, cyclic, and / or aromatic hydrocarbons.

[0091]

[0096] The term "light hydrocarbons" or "LHCs," as variously called, refers to the hydrocarbon fraction that is condensable in the process and thus obtainable as a liquid, but that contains short-chain molecules. Generally, LHCs in a pyrolysis process are considered to have from about 3 to about 8 carbon atoms, possibly with some smaller amounts of C2 and / or C10 molecules. LHCs can include saturated, unsaturated, linear, cyclic, and / or aromatic hydrocarbons.

[0092]

[0097] The term "heavy hydrocarbons" or "HHCs," as variously referred to, refers to hydrocarbon fractions that are condensable in the process and therefore obtainable as liquids, generally having a longer chain composition than LHCs. Generally, HHCs in a pyrolysis process are considered to have at least about 7 carbon atoms (possibly with some smaller C6 molecules), preferably up to about 35 carbon atoms. A preferred range may include a low-range product of about 7 to about 20 carbon atoms, optionally with smaller C6 and / or C21 molecules. For the low-range product, the HHC end point may be about 430°C. Another preferred range may include a mid-range product of about 8 to about 28 carbon atoms. For the mid-range product, the HHC end point may be about 450°C. Another preferred range may include a high-range product of about 10 to about 35 carbon atoms. For the high-range product, the HHC end point may be about 550°C. HHCs may include saturated, unsaturated, linear, cyclic, and / or aromatic hydrocarbons.

[0093]

[0098] The reader skilled in working with petrochemicals will understand that there may be some variation in the boundaries between noncondensables, LHC, and HHC in a distillation process. The overlap and / or variation may depend, among other things, on the temperature, pressure, and flow settings selected, and product specifications can be adjusted to meet desired product qualities.

[0094]

[0099] The features and advantages of the present invention will be understood with reference to the following drawings. [Brief explanation of the drawings]

[0095] [Figure 1] 1 illustrates a schematic representation of an assembly for cracking long chain hydrocarbons. [Figure 2] 2 illustrates a schematic diagram of an exemplary embodiment having an input extruder, a heating zone, and a degassing zone that can be used in the assembly of FIG. 1. [Figure 3] 2 shows a schematic diagram of a degassing dome located between two heating zones that can be used in the assembly of FIG. 1; [Figure 4] 2 shows a schematic diagram of a degassing dome located between two heating zones that can be used in the assembly of FIG. 1; [Figure 5] 2 shows a schematic diagram of a degassing dome located between two heating zones that can be used in the assembly of FIG. 1;

[0096] Description and Exemplary Embodiments

[0105] It will be understood that for brevity and clarity of the figures, where considered appropriate, reference numerals may be repeated in the figures to indicate corresponding or analogous elements or steps. Furthermore, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments described herein. However, those skilled in the art will understand that the embodiments described herein may be practiced without these specific details. Furthermore, this description should in no way be considered as limiting the scope of the embodiments described herein, but merely as an illustration of implementations of the various embodiments described herein. Following are descriptions of specific embodiments of the present invention, shown by way of example only and with reference to the drawings.

[0097]

[0106] 1 shows an apparatus comprising a heating device 11 and a cracked hydrocarbon gas and cracking liquid separation vessel 12. The heating device 11 is in communication with the separation vessel 12 for supplying fluids (liquid and gas) to the separation vessel 12. More specifically, the heating device 11 supplies fluids containing (partially) cracked hydrocarbons in both gaseous and liquid states at pyrolysis temperatures to the separation vessel 12.

[0098]

[0107] In some embodiments, the feeding device 7 is arranged to charge the heating device 11 with material containing long-chain hydrocarbons, such as waste plastics as discussed above. In some embodiments, the feeding device comprises an actuator 8 for heating and / or advancing the material containing long-chain hydrocarbons. In some embodiments, the actuator is a screw auger 8 arranged to advance and heat the material containing long-chain hydrocarbons. In some embodiments, the screw auger 8 moves the material, and internal friction of the material causes it to heat and melt. In further embodiments, the feeding device 7 includes a heating device, such as an electric heater, or a heating device filled with a heating medium, such as thermal oil. The feeding device 7 extrudes the material containing long-chain hydrocarbons into the heating device 11.

[0099]

[0108] The material is preferably heated to about 250-325°C in the extruder 7. Moisture present in the plastic material can be driven out of the plastic material at these temperatures and released via the extruder gas release 200. The released gases may also contain pollutants and acidic substances and can therefore preferably be neutralized with sodium hydroxide solution in a gas scrubber and disposed of.

[0100]

[0109] Other contaminants may be organic materials, for example, originating from food waste or from other materials that the plastic is packaging for, e.g., oils, food, cosmetics, hygiene products such as soap, etc. Other contaminants may originate from plastic fillers or additives that may commonly be added to plastics to improve certain properties such as color, gas barrier properties, elasticity, etc. Contaminants can be considered as all unwanted materials that are rejected in the gas phase at this stage of the process.

[0101]

[0110] In the illustrated embodiment, four heating zones are shown. Heating zones 1, 2, 3, and 4 can each be a heat exchanger, preferably a shell-and-tube heat exchanger. Heating zones 1, 2, 3, and 4 are in series and form a flow path for the plastic material containing long-chain hydrocarbons. Heating zones 1, 2, 3, and 4 provide a continuous or gradual increase in exposure temperature along the flow path. Heating is preferably gradual to reduce or avoid char formation due to excessive temperature differentials.

[0102]

[0111] Heating device 11 heats and melts the raw plastic material, raising its temperature to the pyrolysis temperature. Cracking may begin in any of heating zones 1, 2, 3, or 4, but the majority of cracking in the heating zones preferably occurs in heating zone 4, which is the hottest of the four. The pyrolysis temperature can be 360°C or higher, more preferably 390°C or higher, preferably 395°C or higher, preferably 400°C or higher, more preferably 410°C or higher. The pyrolysis temperature can range from 360 to 550°C, more preferably 390 to 450°C.

[0103]

[0112] According to the present invention, one or more degassing zones are included in the heating device 11, preferably between heating zones 1, 2, 3, and / or 4. Degassing of the heating zones is preferably carried out in a temperature range of 220°C to about 350°C, more preferably about 280°C to about 340°C, more preferably about 300°C to about 330°C, and most preferably about 330°C. At these temperatures, it is believed that halogen-containing plastics such as PVC undergo significant cracking, resulting in the production of Cl-containing gases such as HCl, which can then be extracted as a gas from the heated plastic liquid. Without wishing to be bound by theory, it is believed that applying the above-mentioned limited temperatures can advantageously limit cracking of plastic components such as polypropylene and polyethylene in the zone where HCl is removed.

[0104]

[0113] 2, an apparatus for heating and melting plastic raw materials to a liquid state and subsequently heating to remove contaminants, particularly halogens and chlorine, is shown. Solid waste plastic raw materials, including, for example, a portion of PVC, are fed into an extruder 7, where a screw auger 8 is arranged to advance, compress, and heat the material containing long-chain hydrocarbons. Internal friction of the plastic material under the influence of the auger 8 heats and melts the material. Water in the plastic material is thermally expelled and removed via a gas discharge 200. The feeding device 7 further transports the molten plastic to the first heating zone of a heating device 11.

[0105]

[0114] The illustrated heating zone is a shell-and-tube heat exchanger 1 that can be heated by thermal oil supplied to the shell as shown by arrow 201. Molten plastic material enters the heat exchanger 1 via inlet 202 and is transported through the tubes of the heat exchanger 1, allowing for continuous flow heating of the molten plastic material. The first heating zone heats the molten plastic, thereby increasing its temperature and reaching a temperature of approximately 220°C to approximately 350°C at outlet 203 upon exiting the first heating zone. At these temperatures, halogen-containing plastic polymers, such as PVC, tend to thermally decompose, producing chlorine-containing gases, such as HCl. The gases arise from thermal decomposition in the bulk of the molten liquid and are dispersed, either due to or alternatively to flow disturbances within the tubes of the heat exchanger 1. Thus, a mixture of gas and liquid exits the heat exchanger 1 through outlet 203.

[0106]

[0115] The mixed gas and liquid mass leaving the outlet 203 of the heat exchanger 1 passes to a degassing zone in the form of a degassing vessel (degassing dome) 204 .

[0107]

[0116] The illustrated degassing vessel 204 is elongated and vertically oriented. The mixed gas and liquid mass separates under gravity within the degassing vessel 204. Liquid 220 forms in the lower portion and gas forms in the upper portion, with a liquid level 206 defining the boundary between them.

[0108]

[0117] The liquid 220 is continuously discharged via a liquid outlet 223 located in the lower part of the degassing vessel 204 below the liquid level 206. The liquid then proceeds to a series of further heat exchangers 2, 3, 4, similar to the first heat exchanger 1. In each heat exchanger, the molten plastic material is heated to progressively higher temperatures until it is heated to a final temperature in the range of 360°C to about 550°C, before being sent to the separation vessel 12 as the output liquid phase of the heating zone.

[0109]

[0118] The gas atmosphere 221 in the degassing vessel 204 can be released through a gas outlet 222 under the control of a gas outlet valve 205. The released gas may contain high levels of acid gases such as HCl and may then be sent to a caustic scrubber.

[0110]

[0119] The degassing vessel 204 is provided with one or more liquid level sensor systems LC. Such liquid level monitoring sensors may include radar sensors, temperature sensors, and / or gamma ray sensors. One, several, or all of these sensors may provide a convenient and reliable determination of the liquid level in the degassing zone, preferably the degassing vessel.

[0111]

[0120] The liquid level in the degassing chamber can be controlled by determining the liquid level via an provided sensor and adjusting the rate of gas release from the gas outlet 222 by controlling the gas outlet valve 205. This control can be implemented to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid inlet and outlet. Additionally or alternatively, the liquid level in the degassing chamber can be adjusted by controlling the rate of liquid input and / or output to and from the degassing chamber to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid inlet and outlet.

[0112]

[0121] The liquid level in the degassing vessel 204 can be measured in several different ways. For accuracy, more than one or all of the alternatives discussed can be implemented. Preferably, the level control measurement includes a gamma sensor, a radar sensor, and a temperature sensor.

[0113]

[0122] The liquid level in the degassing vessel 224 is complex to measure: some sensors can fail due to contamination or deteriorate due to harsh conditions, and other sensors can give false readings and be inaccurate due to foaming on the liquid surface.

[0114]

[0123] A radar measurement device, preferably a guided wave radar measurement device, may be provided. The guided wave radar measurement device is installed inside the degassing vessel 204. A guided wave radar level transmitter is installed on top of the degassing vessel 204. The guided wave radar measurement device can provide a wide operating range with good reliability. In particular, rod-type guided wave radar is suitable for operation in foaming liquids, and the measurement device operates independently of noise, pressure, temperature, and density fluctuations. Furthermore, contamination of the guided wave radar probe or the inner surface of the separation vessel has only a minimal effect on measurement accuracy.

[0115]

[0124] A temperature measurement level sensor device, preferably a multi-point temperature measurement sensor device, can be used. The multi-point temperature measurement device is installed within the degassing vessel 204. The temperature measurement rod is equipped with a series of separate temperature sensors spaced along the vertical length of the rod, e.g., two or more, five or more, or about twelve or more. The liquid level can be assessed based on the temperature difference between adjacent sensors on the rod. It has been found that the liquid phase is typically, if not always, several degrees warmer than the vapor phase, e.g., 3°C to 6°C between the vapor and liquid phases.

[0116]

[0125] The accuracy of the temperature measurement will depend on the number of temperature sensors provided on the rod and the spacing of the temperature sensors.

[0117]

[0126] A further advantage of temperature-based liquid level measurement is that it simultaneously provides information about the overall process in the degassing dome, especially during start-up or transient conditions.

[0118]

[0127] An external radiation measuring device, preferably an external gamma source level measuring device, can be used for liquid level measurement.

[0119]

[0128] In this case, the degassing vessel 204 is equipped with an external radioactivity level measurement device comprising a radiation source (preferably a gamma or X-ray source) and a radiation detector. The liquid level can be determined based on whether liquid is present to block gamma radiation at a given level. The radioactivity level measurement has been found to provide accurate liquid level measurements regardless of the dynamic processes and conditions in the pyrolysis zone, including foaming and potential fouling. Notably, the radioactivity level measurement does not require an internal probe or other internal sensor.

[0120]

[0129] The pressure in the degassing zone is preferably 2 to 80 bar absolute, 3 to 70 bar absolute, or 5 to 60 bar absolute. The pressure can be 2 to 10 bar absolute. At these pressures, especially at the temperatures indicated above, halogen-containing gases can be extracted as gas from the heated plastic mass.

[0121]

[0130] The pressure of the degassing zone will depend, at least in part, on the rate of gas phase production upstream of and within the degassing zone. The rate of gas phase production may vary with variations in feed composition; for example, if the feed has a low level of PVC, less chlorine gas may be produced. To maintain the pressure in the degassing zone, an inert gas, such as nitrogen gas, may be injected into the degassing zone.

[0122]

[0131] FIG. 3 shows a more detailed view of the degassing vessel 204 located between the first heat exchanger 1 and the subsequent heat exchanger 2. In the illustrated embodiment, the molten plastic flows from left to right. The molten plastic passes through the single tube of the first heat exchanger 1 and is heated to a temperature at which the halogen-containing plastic decomposes to form halogen-containing gas phase / bubbles 225. The concentration increases as the molten plastic is gradually heated more within the first heat exchanger 1, resulting in a dispersion of gas and liquid. The dispersion proceeds to the degassing vessel 204, where the gas and liquid phases separate into gas phase 221 and liquid 220. The gas phase 221 can be released through the gas outlet valve 205 under the control of the liquid level control system LC, and the liquid is sent to the tube of the subsequent heat exchanger 2 via the liquid outlet 223. Although not shown, additional degassing vessels may be located downstream of the subsequent heat exchanger 2.

[0123]

[0132] Referring to Figure 4, a system similar to that of Figure 3 is illustrated, except that, for example, heat exchangers 1 and 2 are provided with more tubes which can assist in improving heat transfer to the molten plastic material.

[0124]

[0133] 5, an alternative embodiment is shown in which a degassing vessel 204 is provided between the first heat exchanger 1 and the second heat exchanger 2, and a third heat exchanger 3 is provided. In the illustrated embodiment, the heat exchangers 1, 2, and 3 are vertically aligned. Gas 225 rises within the first heat exchanger 1 toward a gas line 210 connecting the upper portion of the first heat exchanger 1 to the degassing vessel 204, while a liquid line 212 is provided connecting the lower portion of the first heat exchanger 1 to the degassing vessel 204. The gas 225 rises within the first heat exchanger 1 to the gas line and can proceed primarily in the vapor phase to the degassing vessel, where separation from the liquid is completed. An additional gas line 213 is provided, allowing the gas to proceed directly from the second heat exchanger 2 to the third heat exchanger 3.

[0125]

[0134] Referring again to FIG. 1, the molten partially pyrolyzed plastic material exits heating zone 4 at pyrolysis temperatures and passes into separator vessel 12 via separator vessel inlet 14 .

[0126]

[0135] In the separator vessel 12, the incoming cracked gas and liquid separate. The gas rises and exits the partial condenser 5, and the liquid falls to the bottom of the separator vessel 12.

[0127]

[0136] A recycle loop 26 is provided for removing the liquid, partially pyrolyzed plastic material collected in the separation vessel 12 by means of a pump 27. The removed liquid is reheated to pyrolysis temperatures by a heat exchanger 28 and then returned to the separation vessel 12, together with fresh feed in the illustrated case. This recycle loop 26 increases the residence time of the long-chain hydrocarbons at the pyrolysis temperature so that they are subjected to further pyrolysis and broken down into shorter-chain hydrocarbons, finally exiting via the partial condenser 5.

[0128]

[0137] The recycle loop 26 provides for reheating and reintroducing heat into the separation vessel 12 so that the separation vessel 12 remains at pyrolysis temperatures. Heat is carried to the separation vessel 12 by the incoming reheated material stream supplied by the recycle loop 26.

[0129]

[0138] In the preferred embodiment shown, the separation vessel 12 is not heated.

[0130]

[0139] The term "unheated" means not heated by any source other than the heat carried by the incoming heated material.

[0131]

[0140] It has been found useful to avoid providing heating means on or within the separation vessel, as can be found in some prior attempts. This can help reduce char formation in the separation vessel 12 and reduce or avoid the need for special agitation means. For example, prior attempts have found that internal heaters, such as heating coils, can cause charring of the pyrolysis material on the surfaces of the heating elements. This charring can represent a loss of product and can collect on the heating elements, requiring downtime for cleaning and maintenance. The same can be true for cracking reactor-type vessels that heat the vessel walls to bring or maintain the processed material at pyrolysis temperatures. Charring can occur on the interior surfaces of the cracking reactor walls, requiring complex mixing, cleaning, and downtime. Nevertheless, the use of direct heating of the separator vessel, such as via a jacket or internal heat exchangers or heating coils, is not precluded from use in some embodiments or aspects of the present invention and may be used to provide all or a portion of the heat requirements of the pyrolysis zone(s). For example, external heating such as a thermal oil jacket or electrical heating may be used to maintain a minimum temperature during standby or start-up.

[0132]

[0141] In the preferred embodiment shown, separation vessel 12 is not provided with an agitator, such as a stirrer or auger. Without wishing to be bound by theory, it is believed that including an auger or similar agitation device to agitate the liquid in the separator vessel may be disadvantageous because it introduces complexity, creates surface areas for carbon / char buildup, reduces efficiency and requires maintenance, and may disrupt the flow pattern imparted by the injection or material. However, an agitator in separation vessel 12 may optionally be provided or is not excluded from some embodiments and aspects, as it may be useful to improve mixing within separation vessel 12.

[0133]

[0142] Upon entering separation vessel 12 via inlet 14, the plastic material is at its pyrolysis temperature and is therefore undergoing pyrolysis. Cracking of the plastic material results in the production of a wide range of substances with a wide range of boiling points. The plastic material exiting heating device 11 and entering separation vessel 12 via inlet 14 includes at least both gaseous and liquid components, and the liquid component includes, and may consist essentially of, at least partially cracked plastic material. The liquid component may also include molten, uncracked plastic material. The plastic material exiting heating device 11 and entering separation vessel 12 via inlet 14 may further include silt and other solid detritus, such as sand, aluminum, or other metal particles.

[0134]

[0143] The operating pressure of the cracked gas and cracking liquid separator vessel 12 is preferably greater than ambient to ensure that ambient air does not enter the system. The pressure can be between 1 bar (absolute) and 5 bar (absolute), between 1 bar (absolute) and 3 bar (absolute), between 1 bar (absolute) and 2 bar (absolute), or between 1 bar (absolute) and 1.5 bar (absolute), or between 1 bar (absolute) and 1.05 bar (absolute).

[0135]

[0144] The illustrated separation vessel 12 is elongated and arranged substantially vertically. Non-vertical arrangements, such as inclined or horizontal, are also contemplated. The pyrolyzed gaseous material rises in the separation vessel 12, while the liquid (partially) pyrolyzed material falls under gravity. In this manner, the gaseous and liquid materials separate and separate in the separation vessel 12.

[0136]

[0145] The gaseous hydrocarbon material rising in separation vessel 12 is discharged through upper outlet 132 and passes via line 6 to partial condenser 5. Partial condenser 5 is remote from and positioned downstream of separation vessel 12. Partial condenser 5 is in fluid communication with separation vessel 12 via line 6. Line 6 is a gas line that transports gas to the partial condenser. Liquid does not pass through line 6.

[0137]

[0146] Partial condenser 5 is positioned and / or configured to remove a heavy fraction (a lower, higher point fraction) from the exiting gas before the exiting gas is sent further to the full distillation or condenser section of the apparatus and process. In partial condenser 5, the gas is cooled as discussed below. As the gas is cooled, the heavier fraction can condense and be collected, while the lighter fraction remains in gaseous form and is sent via line to reboiler 16.

[0138]

[0147] The partial condenser 5 is preferably provided with a packed column 28 having (optional) random packing such as rings, e.g., Raschig rings, which increases the contact surface area between the gas and the liquid being condensed in the partial condenser. As is known in condensation processes, this packed column 28 can aid in effective condensation by providing a large solid surface area for the gas to condense upon.

[0139]

[0148] Partial condenser 5 is also preferably provided with a temperature controlled cooling element 29, such as a cooling coil supplied with a temperature regulated cooling medium. The temperature of cooling element 29 is controlled to cause condensation of long chain hydrocarbons (e.g., longer than C22), and this condensed material falls under gravity into the lower portion of partial condenser 5. Cooling element 29 is preferably downstream of packed column 28, although other arrangements are possible.

[0140]

[0149] Alternatively, or additionally, selective condensation may be achieved by a cooling jacket (not shown) acting as a cooling element, or the partial condenser may be an external (full reflux) condenser.

[0141]

[0150] The gases (C1 to C20 / C22, possibly up to C35) that do not condense in the packed column 28 or the cooling element 29 are discharged via the upper outlet of the partial condenser and pass via line 30 to a downstream distillation unit of the type commonly known for distillation applications in the petrochemical sector, for example used for the distillation of crude oil or mineral oil fractions.

[0142]

[0151] The downstream distillation section can be designed according to industry standards known to those skilled in the art. The gas can be fractionated into a gaseous fraction and a liquid fraction. In the distillation unit, the liquid fraction can be stripped as a middle distillate, and the gaseous fraction can be stripped as a light-boiling material. Hydrocarbon products from the distillation unit can include butane, propane, kerosene, diesel, fuel oil; light distillates such as LPG, gasoline, naphtha, or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof. The hydrocarbon products can be saturated, unsaturated, linear, cyclic, or aromatic. Additional products can include non-condensable gases containing methane, ethane, ethene, and / or other small molecules. The products can be a source of raw material for a steam cracker for the production of plastics.

[0143]

[0152] Hydrocarbons that condense in the partial condenser 5 (eg, containing C22 and higher chains, and possibly small amounts of carbon chains below C22) collect as liquid 31 at the bottom of the partial condenser 5 .

[0144]

[0153] The liquid level in the bottom of the partial condenser is controlled by one or more level control sensors and can be discharged batchwise or continuously. Level control of the partial condenser 5 can be achieved continuously by a flow control valve.

[0145]

[0154] The condensed liquid 31 from the partial condenser preferably exits through a lower outlet 32 ​​of the partial condenser and is sent to the reboiler 16 via a line 33 controlled by an optional valve 34. Valve 34 can be either an on-off valve or a control valve.

[0146]

[0155] The condensed liquid 31 collects in the reboiler 16, where it is reheated by a heater 13, preferably an internal heating element or an internal heat exchanger. The reboiler heater 13 can be electrically heated by thermal oil or other type of heating medium. The condensed liquid in the reboiler 16 is heated to a temperature higher than that of the partial condenser. An external heating element or external heat exchanger is also contemplated.

[0147]

[0156] Light hydrocarbon fractions that may unavoidably be carried along with the condensed liquid from the partial condenser can be vaporized or boiled off in this manner and sent to the distillation apparatus via the upper outlet 15 of the reheater vessel. These light hydrocarbon fractions can then be included in the distillation product. This can improve product yields compared to systems or processes in which the partially condensed material is returned directly to the thermal cracking zone. This is also considered preferable to returning the light hydrocarbons to the thermal cracking zone, where they are cyclically heated, re-vaporized, and then re-condensed, potentially subjecting them to further cracking or creating relatively unwanted heat release.

[0148]

[0157] A reboiler 16 is preferably configured as a component of the distillation section and is connected in gas fluid communication through the upper outlet 15 of the reheater vessel.

[0149]

[0158] Liquid 35 collected in the reboiler and not vaporized for distillation through reheater vessel upper outlet 15 is pumped back to separator vessel 12 via line 9 using pump 10 and optionally further heated before entering separator vessel 12. In this manner, the liquid can be further pyrolyzed into more useful lighter products than those condensed in partial condenser 5. For example, liquid can be returned to separator vessel 12 and / or the thermal cracking zone and cracked until they are reduced to chain lengths of C20-C22 or less. Thus, product yields can be improved and / or the ratio of light to heavy products can be more tailored to customer requirements.

[0150]

[0159] Alternatively, the liquid collected in the reboiler and not vaporized through the upper outlet 15 of the reheater vessel for distillation can be collected as a useful product, for example, this product can be paraffin, and can be transported via valve 21 to a collection vessel.

[0151]

[0160] The partial condenser coil 29 typically operates at a temperature between 220° C. and 380° C., and the reboiler typically operates at a temperature between 340° C. and 400° C. Both of these temperatures are below typical crack reactor operating temperatures of less than 390° C. and 450° C.

[0152]

[0161] The liquid pyrolyzed material exiting separator vessel 12 is continuously circulated, preferably by an external pump 27. As the liquid is circulated, it can be reheated by heat exchanger 28 to pyrolysis temperatures for further cracking.

[0153]

[0162] Preferably, a distillation column (not shown) is provided above the upper outlet 15 of the reheater vessel. The distillation column may have a section designed as a packed column, and optionally, intermediate trays may be provided in this packing-containing section, or preferably above this section, on which the liquid fraction (diesel product or HHC) can be collected and discharged. The HHC, e.g., diesel product, discharged from the distillation unit is preferably cooled by a heat exchanger, and part of this cooled diesel product can be recycled to the distillation unit via a recycle stream line to set optimal temperature conditions.

[0154]

[0163] Settings that may result in low range product compositions include: Partial condenser outlet temperature of approximately 290°C Reboiler (liquid) temperature of approximately 360°C The outlet temperature of the upper distillation column is approximately 80°C. LHC condenser temperature of condensed LHC liquid of about 42°C HHC final boiling point: 430℃

[0155]

[0164] Potential configurations that result in mid-range product compositions include: Partial condenser outlet temperature of approximately 320°C Reboiler (liquid) temperature of approximately 380°C Outlet temperature of the upper distillation column is approximately 100°C LHC condenser temperature of condensed LHC liquid of about 42°C HHC final boiling point: 450℃

[0156]

[0165] Configurations that may result in high range product compositions include: Partial condenser outlet temperature of approximately 330°C Reboiler (liquid) temperature of approximately 380°C The outlet temperature of the upper distillation column is approximately 120°C. LHC condenser temperature of condensed LHC liquid of about 55°C HHC final boiling point: 550℃

[0157]

[0166] All documents cited in this detailed description of the present invention are, in relevant part, incorporated herein by reference, and the citation of any document shall not be construed as an admission that such citation is prior art with respect to the present invention. To the extent that a meaning or definition of a term within a document of this document conflicts with a meaning or definition of a term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall control.

[0158]

[0167] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is, therefore, intended in the appended claims to cover all such changes and modifications that are within the scope of this invention.

Claims

1. 1. A method for heating a halogen-containing plastic material to pyrolysis temperatures, comprising: heating and melting the halogen-containing solid plastic raw material to a temperature in the range of about 200°C to about 325°C; removing water vapor and other gases generated during the fluidizing and heating steps; directing molten plastic material into a first heating zone; further heating the molten plastic mass in the first heating zone to a higher temperature in the range of about 220°C to about 350°C to produce a liquid phase and a gas phase, the gas phase being dispersed in the first heating zone; separating the liquid phase and dispersed gas phase to provide a body of primarily gas phase material comprising halogen-containing compounds and a body of liquid phase plastic material; removing at least a portion of the gas phase; Passing the liquid phase material through one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature; and Preferably, sending the output liquid phase of said heating zone at said pyrolysis temperature to a pyrolysis reactor and / or a distillation apparatus. A method comprising:

2. 10. The method of claim 1, wherein the plastic material is heated to a pyrolysis temperature in the range of about 360°C to about 550°C before being sent as an output liquid phase of the heating zone to a pyrolysis reactor and / or a distillation apparatus.

3. 3. The method of claim 1, wherein the separation of the mixed liquid and gas phases of the first heating zone occurs primarily downstream of the first heating zone.

4. 4. The method according to any one of claims 1 to 3, wherein the first heating zone is a heat exchanger, preferably a tube and shell heat exchanger, and more preferably the subsequent heating zone is also a heat exchanger, preferably a tube and shell heat exchanger.

5. 5. The method of any one of claims 1 to 4, wherein molten plastic, gaseous and / or liquid phase matter flows through the heating zone while it is being heated.

6. The method according to any one of claims 1 to 5, wherein the heating zones are arranged in series.

7. 7. The method according to any one of claims 1 to 6, wherein a plurality of heating zones are arranged in series, with at least one downstream heating zone being positioned higher than an upstream heating zone.

8. 8. The method of any one of claims 1 to 7, wherein the separation of the liquid phase and dispersed gas phase is carried out under gravity, with the gas phase rising from the liquid phase.

9. 9. The process according to any one of claims 1 to 8, wherein a final heating zone precedes the pyrolysis reactor and the liquid phase leaving said final heating zone has a temperature of from about 360°C to about 550°C, preferably from about 390°C to about 450°C.

10. The method according to any one of claims 1 to 9, further comprising the step of heating and melting the halogen-containing solid plastic raw material in an extruder.

11. The method according to any one of claims 1 to 10, wherein the extruder is provided with a compression section, optionally including an electric heating section, and an expansion section downstream of the compression section, wherein the halogen-containing solid plastic raw material is compressed in the compression section to be heated and melted, and then expanded in the expansion section to release gases, preferably air and water vapor, and at least a portion of these gases is removed from the extruder.

12. A method according to any one of the preceding claims, wherein the expansion section is followed by the application of compression and heat to the plastic material.

13. The step of heating and melting the halogen-containing solid plastic raw material comprises: compressing and heating the plastic raw material to a temperature above 100°C, preferably in the range of about 200°C to about 320°C; thereafter reducing the pressure in at least one expansion zone, preferably a plurality of expansion zones, to release gas, preferably at least air and water vapor; removing at least a portion of the liberated gas from the extruder; and The remaining plastic material is then compressed and heated to a temperature of about 200°C to about 320°C. The method according to any one of claims 1 to 12, comprising:

14. A method according to any one of claims 10 to 13, wherein the first heating zone is fed by the extruder.

15. 15. The method according to any one of claims 1 to 14, wherein a degassing zone is provided intermediate the first heating zone and the subsequent heating zone, in which the liquid and gas phases produced in the first heating zone separate, and from which at least a portion of the gas phase is removed, preferably under negative pressure.

16. 16. The method of claim 15, wherein the degassing zone is not heated during degassing.

17. 17. A method according to claim 15 or 16, comprising the step of monitoring the liquid level in the degassing zone, preferably by radar, temperature measurement and / or gamma measurement.

18. A method according to any one of claims 15 to 17, wherein the degassing zone comprises a degassing vessel, preferably a degassing dome, separate from the heating zone.

19. A method according to any one of claims 15 to 18, comprising controlling the method so that the temperature of the degassing zone is at most about 350°C, preferably at most 325°C.

20. 20. The method according to any one of the preceding claims, wherein the degassing zone is at a pressure above 2 bar absolute, preferably from 2 bar absolute to 80 bar absolute, preferably from 2 bar absolute to 60 bar absolute, preferably from 2 bar absolute to 50 bar absolute, most preferably from 2 to 10 bar absolute.

21. 21. The method of any one of claims 1 to 20, wherein the halogen is selected from the group consisting of chlorine, bromine, fluorine, and mixtures thereof, preferably the halogen is chlorine.

22. A method according to any one of the preceding claims, wherein the gas phase material comprising halogen-containing compounds is passed to a scrubber, preferably an alkaline scrubber, more preferably a caustic scrubber.

23. 23. The method of any one of claims 1 to 22, wherein the solid plastic feedstock comprises polyethylene and / or polypropylene plastic, preferably the sum of polyethylene and polypropylene in the feedstock is at least 50% by weight, more preferably at least 60% by weight of the feedstock.

24. 24. The method of any one of the preceding claims, wherein the solid plastic feedstock comprises polyvinyl chloride plastic, preferably more than 1 wt%, more preferably more than 5 wt%, of polyvinyl chloride plastic, or the feedstock comprises less than 5 wt%, more preferably less than 1 wt%, of polyvinyl chloride plastic.

25. 25. The method of any one of claims 1 to 24, wherein the solid plastic feedstock comprises polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight of polyethylene terephthalate plastic, or the feedstock comprises less than 4% by weight, more preferably less than 3% by weight of polyethylene terephthalate plastic.

26. 26. The method of any one of claims 1 to 25, wherein the solid plastic feedstock comprises polystyrene plastic, preferably more than 1 wt%, more preferably more than 5 wt%, of polystyrene plastic, or the feedstock comprises less than 20 wt%, more preferably less than 5 wt%, of polystyrene plastic.

27. 27. A method for producing hydrocarbon materials comprising the steps of any one of claims 1 to 26 and the further step of distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein said hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, e.g., LPG, gasoline, naphtha or mixtures thereof; medium distillates, e.g., kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, e.g., fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, which are saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases comprising methane, ethane, ethene and / or other small molecules; and mixtures thereof.

28. 1. An apparatus for heating a halogen-containing plastic material to pyrolysis temperatures, comprising: a heat-melting compartment arranged to heat-melt a halogen-containing solid plastic raw material to a temperature in the range of about 200°C to about 325°C, the heat-melting compartment being provided with an inlet for the plastic raw material, at least one gas outlet for releasing gas evolved from the plastic raw material during heat-melting, and an outlet for the molten plastic material; a first heating zone configured to receive molten plastic material from the heat melting section and further configured to heat the molten plastic material to a temperature in the range of about 220°C to about 350°C to produce a liquid phase and a gas phase, the gas phase being dispersed in the first heating zone; a degassing zone provided with an inlet arranged to receive the liquid phase and dispersed gas phase from the first heating zone, the degassing zone being arranged to allow the dispersed gas phase and the liquid phase to separate into a body of predominantly gaseous material and a body of liquid plastic material, the degassing zone further comprising a gas outlet for discharging the separated gas phase and a liquid outlet for discharging the separated liquid phase, preferably the gas outlet being higher than the liquid outlet; at least one subsequent heating zone arranged to receive said liquid phase from the degassing zone liquid outlet, said heating zone arranged to heat said liquid phase to a higher temperature, preferably a pyrolysis temperature; An apparatus comprising:

29. 29. The apparatus of claim 28, wherein the melting section comprises an extruder for melting solid plastic feedstock.

30. 30. The apparatus of claim 29, wherein the extruder is provided with a compression section and an expansion section downstream of the compression section, the compression section being arranged to compress and heat the solid plastic raw material, and the expansion section being arranged to allow expansion of the compressed plastic material and release of gas from the plastic material, and the extruder is provided with a gas outlet in communication with the expansion section, whereby gas can be removed from the expansion section.

31. 31. The apparatus of claim 30, wherein the extruder further comprises an additional compression and heating section downstream of the expansion section.

32. Apparatus according to any one of claims 28 to 31, wherein the first heating zone is a heat exchanger, preferably a tube and shell heat exchanger.

33. 33. The apparatus of claim 28 or 32, wherein the at least one subsequent heating zone is arranged in series downstream of the first heating zone and positioned higher than the first heating zone, preferably the subsequent heating zone being a tube-and-shell heat exchanger.

34. 34. Apparatus according to claim 28 or 33, wherein the degassing zone is not heated during degassing.

35. 35. Apparatus according to claim 28 or 34, wherein the degassing zone is equipped with a liquid level monitoring sensor, preferably a radar sensor, a temperature sensor and / or a gamma ray sensor.

36. 36. Apparatus according to claim 28 or 35, wherein the degassing zone comprises a degassing vessel separate from the heating zone, preferably the degassing vessel comprising a degassing dome.

37. 37. An apparatus for thermally cracking waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, said apparatus comprising an apparatus according to any one of claims 28 to 36 and at least one pyrolysis zone downstream thereof, and at least one distillation apparatus for distilling the pyrolyzed material to obtain hydrocarbon products, preferably said hydrocarbon products comprising butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, which may be saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases comprising methane, ethane, ethene and / or other small molecules; and mixtures thereof.

38. 1. A method for reducing the halogen, preferably chlorine, content of waste plastic material, comprising: heating the halogen-containing molten plastic mass in the first heating zone to a temperature in the range of about 220°C to about 350°C to produce a mass of mixed liquid and gas phases, said gas phase dispersed in said liquid phase; sending said mixed mass of dispersed gas and liquid through an outlet of the first heating zone to a degassing chamber; separating the dispersed gas phase from the liquid phase in the degassing chamber to result in a body of material in a primarily gas phase comprising a halogen-containing compound, preferably comprising hydrogen chloride, and a body of plastic material in a liquid phase; Releasing at least a portion of the gas phase from the degassing chamber through a gas outlet of the degassing chamber; and passing the liquid phase material through a liquid outlet of the degassing chamber to one or more subsequent heating zones and further heating the liquid phase to a temperature above the pyrolysis temperature. A method comprising:

39. 39. The method of claim 38, wherein the degassing chamber is vertically elongated with a height, the chamber is provided with a liquid inlet, and the liquid outlet is positioned lower in the height of the chamber than the gas outlet, and the method further comprises the step of passing the mixed mass of dispersed gas and liquid through the outlet of the first heating zone to the liquid inlet of the degassing chamber.

40. 40. The method of claim 39, wherein the liquid level in the degassing chamber is monitored and one or more of the rate of liquid input to the degassing chamber, the rate of liquid output from the degassing chamber, and the rate of gas release are controlled to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid outlet.

41. 41. The method of any one of claims 38 to 40, further comprising the step of heating and melting a solid halogen-containing plastic raw material, for example, waste plastic particles or waste plastic pellets containing polyvinyl chloride, to a temperature in the range of about 200°C to about 325°C, and sending the heated halogen-containing molten plastic material to the first heating zone, thereby providing a heated halogen-containing molten plastic material.

42. 43. The method according to any one of claims 38 to 42, wherein the first heating zone is a heat exchanger, preferably a tube and shell heat exchanger, and more preferably the subsequent heating zone is also a heat exchanger, preferably a tube and shell heat exchanger.

43. 44. A method according to any one of claims 38 to 43, wherein the mass in molten plastic, gaseous and / or liquid phase flows through the heating zone while it is heated.

44. 1. An apparatus for heating a halogen-containing plastic material to pyrolysis temperatures, comprising: a first heating zone configured to receive molten plastic material and increase the temperature of the molten plastic material to a temperature in the range of about 220°C to about 350°C to produce a liquid phase and a gas phase, the liquid phase and the gas phase being mixed in the first heating zone; a degassing zone provided with an inlet arranged to receive the mixed liquid and gas phases from the first heating zone, the degassing zone being arranged to allow the mixed liquid and gas phases to separate, preferably under gravity, into a body of predominantly gaseous material and a body of predominantly liquid plastic material, the degassing zone further comprising a gas outlet for discharging the separated gas phase and a liquid outlet for discharging the separated liquid phase, preferably the gas outlet being positioned higher than the liquid outlet; at least one subsequent heating zone positioned to receive the liquid phase from the degassing zone liquid outlet, the at least one subsequent heating zone positioned to heat the liquid phase to a higher temperature, preferably a pyrolysis temperature; An apparatus comprising:

45. 45. The apparatus of claim 44, wherein a heat-melting section is disposed upstream of the first heating zone, the heat-melting section being configured to heat-melt the halogen-containing solid plastic raw material to a temperature in the range of about 200°C to about 325°C, the heat-melting section being provided with an inlet for the plastic raw material, at least one gas outlet for releasing gas generated from the plastic raw material during heat-melting, and an outlet for molten plastic material.

46. 46. ​​Apparatus according to claim 44 or 45, wherein the degassing zone comprises a degassing chamber, preferably having a height, the chamber being provided with the liquid outlet which is positioned lower in the height of the chamber than the gas outlet.

47. 47. Apparatus according to any one of claims 44 to 46, further comprising a controller arranged to determine the liquid level in the degassing chamber and to adjust the rate of liquid input and / or output to and from the degassing chamber to maintain the liquid level in the degassing chamber below the gas outlet and above the liquid inlet and liquid outlet.

48. Apparatus according to any one of claims 44 to 47, wherein the degassing zone is equipped with a liquid level monitoring sensor, preferably a radar sensor, a temperature sensor and / or a gamma ray sensor.

49. 10. An apparatus for thermally cracking waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, said apparatus comprising an apparatus according to any one of claims 44 to 48 and at least one pyrolysis zone downstream thereof, and at least one distillation apparatus for distilling the pyrolyzed material to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, which may be saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases, including methane, ethane, ethene and / or other small molecules; and mixtures thereof.

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