A Rotary Reactor for Pyrolysis and Torrefaction

This invention relates to the field of mechanical engineering and waste management.

Specifically, this invention relates to a rotary reactor for pyrolysis and torrefaction.

Waste management comprises all activities and actions required to manage waste from its inception to its final disposal. This includes amongst other things, collection, transport, treatment, and disposal of waste, together, with monitoring and regulation. It also encompasses legal and regulatory frameworks that relates to waste management encompassing guidance on recycling, and the like.

Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen (or any halogen). It involves simultaneous change of chemical composition and physical phase, and is irreversible. The word is coined from the Greek-derived elements pyro “fire” and lysis “separating”.

An object of the invention is to provide a machine which performs torrefaction and pyrolysis/chemical recycling of various wastes like MSW derived RDF, Plastics, Tires, Biomass, Agricultural Wastes into alternate fuel.

According to this invention, there is provided a continuous-feed rotary reactor system, for pyrolysis and torrefaction, said reactor comprising:

In at least an embodiment, wherein said first airlock valve and said second airlock valve being a valve selected from a group of valves consisting of slide gate valves, double flap valves, butterfly valves, and their combination valves.

In at least an embodiment, wherein said operative top hooper is a relatively small hopper which is coupled to said operative bottom hopper which is a relatively large hopper.

In at least an embodiment, wherein said operative top hooper is a relatively small hopper which is coupled to said operative bottom hopper which is a relatively large hopper, said hopper comprising supplementary agitators depending on capacity.

In at least an embodiment, wherein said system comprising a control module for controlling said first combinatorial airlock valve system, with instructions concerning controlling valves, said instructions being:

In at least an embodiment, wherein said each spiral ribbon having pitches selected from varying pitches, said pitch being correlative to desired feedstock and desired residence time in said reactor.

In at least an embodiment, wherein said system comprising a control module for controlling said second combinatorial airlock valve system, with instructions concerning controlling valves, said instructions being:

In at least an embodiment, wherein said system comprising:

In at least an embodiment, wherein said reactor is a horizontal rotary type reactor.

According to this invention, there is provided a rotary reactor for pyrolysis and torrefaction.

This system is configured to perform torrefaction and pyrolysis/chemical recycling of various wastes like MSW derived RDF, Plastics, Tires, Biomass, Agricultural Wastes into alternate fuel.

illustrates a schematic block diagram of this machine.

In at least an embodiment, the system comprises an input hopper (H, H), which is a two-step hopper (H, H) comprising at least an operative top hopper (H) and at least an operative bottom hopper (H). This input hopper system (H, H) receives feed (F), and is configured with a first combinatorial airlock valve system (AV, AV) such that the operative top hooper (H) is a relatively small hopper which is coupled to the operative bottom hopper (H) which is a relatively large hopper. A first airlock valve (AV), at an operative bottom of the operative top hopper, is configured to control feed flow between the operative top hopper (H) and the operative bottom hopper (H). A second airlock valve (AV), at an operative bottom of the operative bottom hopper, is configured to control feed to a feeding screw (FS). This hopper (H, H) system along with the first combinatorial airlock valve system (AV, AV) ensures that in a continuous feed machine, oxygen does not enter the system. Moreover, this system ensures that even relatively lighter material (which, typically, are not necessarily gravity-fed) can also be fed through this feeding system)

In at least an embodiment, of working, feed is provided to an operative top hopper (H). At this time, first airlock valve (AV) is shut and second airlock valve (AV) is shut. Then, once a determined batch of feed is entered at the operative top hopper (H), the first airlock valve (AV) is opened and the second airlock valve (AV) is still shut. Feed flows from the operative top hopper (H) to the operative bottom hopper (H). The first airlock valve (AV) is closed and, then, the second airlock valve (AV) is opened to allow the determined continuous feed, from the operative bottom hopper (H), to move forward to other embodiments/mechanisms of this system.

First airlock valve (AV) and second airlock valve (AV) can be slide gate valves, double flap valves, butterfly valves, and the like

This hopper system (H, H), along with the first combinatorial airlock valve system (AV, AV), forms a unique auger-based system hopper to resolve bridging of waste during feeding.

The first combinatorial airlock valve system (AV, AV) forms an airlock feeding which is equipped, preferably, with an air tight metal-to-metal knife edge gate valve system with a unique auger-based hopper that resolves bridging of waste during feeding. The auger can be controlled to differential feed rates.

In at least an embodiment, feed from the feeding screw (FS) is moved to a reactor (R). The reactor (R) is the heart of the pyrolysis machine. It comprises a reaction vessel and a furnace. Carbon (CB) is discharged from reactor (R). The reactor is fed with raw material (or feed), driven by the feeding screw (FS), received from the hopper system (H, H), intermittently, and catalyst, if required, mixed in a certain proportion; output obtained is Hydrocarbon gas and carbon char which is fed to further embodiments and mechanisms of this invention.

Challenges with Prior Art Rotary Kiln Reactors are:

Using the internal multiple spiral ribbons, the current invention solves problems relating to lumping of waste by breaking it into smaller lumps and, thereby, achieving a relatively faster rate of cracking and, also achieving, better heat transfer.

illustrate various views of the auger-based hopper system of this invention.

Typically, the raw materials can be tyres, different types of plastics, biowaste like wood, leaves, trees, plant waste, food waste, coconut shells, other hydrocarbon wastes and the like.

Typically, the catalysts are a mix of activated minerals in different ratios. Other catalysts can be silica alumina and, or ZSMand, or NaOH to be mixed in the reactor along with the feedstock in different ratios based on the type of feed. In the catalytic tower ZSM, Bleaching earth, ceramic filter, Zeolites, or special catalysts for purification of hydrocarbon gas is used, depending on the feedstock and desired purification.

The furnace is heated so that the temperature inside the reactor is in a temperature range where catalytic degradation takes place depending on various feedstock.

Preferably, the reactor is a horizontal rotary type reactor with many unique internal features. In prior arts, a rotary kiln has many problems for usage in pyrolysis and torrefaction. E.g., lumping of material, inability to increase or decrease residence time based on varying feedstocks. One of the major challenges in the process, of pyrolysis and torrefaction, is that most systems are designed to handle only one type of feedstock at a time and do not allow manipulation of residence time beyond pre-defined revolutions per minute (rpm) control. The length of the reactor is also a challenge as the bigger the reactor the more the thickness and so more energy is required. Also, bending and failure of rotary kilns and maintaining alignment of the reactor is a challenge in prior arts.

illustrates a view of the reactor showing its spiral ribbons.

In at least an embodiment of this invention, the reactor (R) is configured with internal circumferentially placed spiral ribbons (RB). Typically, one or more spiral ribbon elements line an inner circumference of the reactor (R). In at least an embodiment, each spiral ribbon can have different/varying pitches. These spiral ribbons break the input material received from the feed screw (FS) into small chunks and move it across the reactor's (R) bed in small heaps (thus, bigger lump related problems are overcome); thereby, allowing uniform heat distribution, relatively greater yield, and manipulation of residence time beyond pre-defined rpm of the reactor.

Heating can be one of electric heating, gas heating, or liquid fuel-driven heating.

illustrates a view of the carbon removal mechanism.

In at least an embodiment, feed from the reactor (R) is moved to a carbon removal mechanism (CRM) with a second combinatorial airlock valve system (AV, AV) which comprises at least a carbon removal screw configured to receive. Discharge is activated by a discharge screw attached to this system. Carbon discharge control enables the system to manipulate residence time.

In prior arts, the systems were open ended systems where one could not stop carbon output from falling out. With the introduction of the carbon removal mechanism (CRM), which comprises the second combinatorial airlock valve system (AV, AV), residence type can, now, be manipulated. In at least an embodiment, the third airlock valve (AV) is provided at the end of the carbon removal mechanism (CRM) and the fourth airlock valve (AV) is provided at the start of an outlet from where hydrocarbon gas/syngas exits (G) the system.

In at least an embodiment, the output of carbon char, from the reactor (R), is removed with an auger screw mechanism, which is a part of the carbon removal mechanism (CRM), and an airtight collection mechanism, which comprises the second combinatorial airlock valve system (AV, AV); this further enhances safety of the system.

Nitrogen is purged during the entire cycle. Solids and vapours are separated out and taken to a cyclone separator (cyclone mechanism) and tar and heavy fractions are separated out. The cyclone mechanism is further extended to hold vapour stage cracking catalysts to further purify the hydrocarbon gas (G). Manipulation of residence time is also due to this invention's carbon removal mechanism (CRM) which allows removal of carbon char at will; as opposed to prior arts.

Problems relating to ‘residence time’ were solved by this carbon removal mechanism (CRM) which allows removal of carbon char at set intervals. This allows the reactor (R) to be relatively smaller in size, having relatively lesser thickness of shell, and requiring relatively lower energy requirements. Carbon char is discharged by the second combinatorial airlock valve system (AV, AV) of this invention and, then, transferred to a silo using a water jacketed screw. This allows continuous removal of carbon and also makes it programmable for different feedstocks.

In at least an embodiment, of working, Carbon char is discharged by the second combinatorial airlock valve system (AV, AV). When carbon char is to be removed, the third airlock valve (AV) is shut and the fourth airlock valve (AV) is shut. In other instances, the fourth airlock valve (AV) is always open. Furthermore, direction of auger screw (AS), of the carbon removal mechanism (CRM), is towards the reactor (R) when the third airlock valve (AV) is open. Furthermore, direction of auger screw (AS), of the carbon removal mechanism (CRM), is away from the reactor (R) when the third airlock valve (AV) is shut and the fourth airlock valve (AV) is open.

Because of this system, comprising the carbon removal mechanism (CRM), it allows the removal of carbon char at will and allows operation of the systems with multiple feedstocks. It can be determined as to what residence time suits a particular feedstock and the data can be used to program the system. This ensures that one can make relatively smaller, more efficient, reactors that will work with the same residence time as longer reactors and at the same time be more efficient, economical, and dynamic in its application.

Reference numeral CT refers to Carbon Tank.

In accordance with another embodiment of this invention, there is provided a cyclone mechanism. The hydrocarbon gas (G) from the catalytic degradation comes out of the reactor and is cleaned using a cyclone mechanism where the heavier carbon particles and long chain hydrocarbons condense and the lighter fraction is taken to a catalytic tower (CT). The syngas/hydrocarbon gas velocity also decreases in the cyclone due to which the gas gets more residence time in the catalytic tower and subsequent line.

In accordance with another embodiment of this invention, there is provided a Catalytic Tower (CT). The catalytic tower is used to purify the hydrocarbon gas using catalyst in the vapour phase. Unwanted components like H2S, SOX, NOX etc. can be used using appropriate catalyst and scrubbers. The reactor is fitted with a reflux cum catalyst chamber. This chamber has several sections where one can add catalyst, ceramic filter, packing material to manipulate the quality of the output fuel. This ensures that the heavy hydrocarbon material is condensed as it comes out of the reactor and comes in contact with the packing and catalyst and falls back in to the reactor and only the light hydrocarbon goes to the condensation line.

In accordance with another embodiment of this invention, there is provided a Distillation Column. The distillation of pyrolysis oil is a separate process and can be done in the same machine, which is a unique feature of this invention. The oil that is derived from pyrolysis can be again distilled to higher value products like naphtha range, diesel and gasoline range of products using the machine along with our distillation column.

In accordance with another embodiment of this invention, there is provided at least a Condenser (CS). Shell and tube condensers are used to cool the hydrocarbon gas from the reactor to liquid pyrolysis oil.

In accordance with another embodiment of this invention, there is provided an Oil Gas Separation tower. The oil and the uncondensed gas from the condenser are passed through the oil gas separator where the oil flows to the oil storage tank (OT) and the gas is separated and taken to the Scrubber. This tank also acts as a pressure regulator. The oil and the uncondensed gas from the condenser are passed through the oil gas separator where the oil flows to the storage tank and the gas is separated and taken to a scrubber.

In accordance with another embodiment of this invention, there is provided a Gas Scrubber. Further cleaning of the gas is done in the gas scrubber. The gas from the Oil gas separator is further cleaned of moisture and Sulphur by passing it through a Catalyst bed.

Reference numeral BT refers to Bubbler Tank.

In accordance with another embodiment of this invention, there is provided a Storage Tank. The oil is stored in the storage tank and again used by the reactor.