HK40116444A - Pre-treatment apparatus and process to produce feedstock for thermochemical decomposition - Google Patents

Description

PRE-TREATMENT APPARATUS AND PROCESS TO PRODUCE FEEDSTOCK FOR THERMOCHEMICAL DECOMPOSITION

Field of the Invention

The present invention relates to an apparatus and method of material preparation for thermochemical decomposition such as pyrolysis, where a base material is prepared in a pre-treatment apparatus and process before decomposition.

Background to the Invention

Raw materials typically used in the fast or slow pyrolysis process includes taking solid refuse base material e.g., biomass, waste tyre, waste plastic and waste rubber materials, and thermally decomposing the base material at elevated temperatures to change the composition.

Fast pyrolysis is the process of heating biomass in the absence of oxygen, wherein the waste material is treated in a temperature range of 200 to 1,000 °C.

Pyrolysis is considered one of the most suitable techniques among known technologies e.g., polymerisation technologies for converting biomass into value-added goods due to its broad applicability.

Fast pyrolysis is known for producing increased bio oil yield and slow pyrolysis is known for producing an increased biochar yield. These and other decomposition processes and the comparative yields are illustrated in Table 1 below.

Process Temperature (°C) Residence duration Char Carbon content of char (wt%) yield (wt%) Slow pyrolysis 400-600 min to days 20-40 95 Fast pyrolysis 500-1000 -1 s 12-26 74 Gasification 800-1000 5-20 s -10 Hydrothermal carbonization -180-250 1-12 h 30 -60 70% Torrefaction -290 10-60 min 61-84% 51-55% Table 1 -comparing decomposition processes It will be appreciated, by adjusting the operating conditions, the properties of pyrolysis products may be altered. Setting up larger fast pyrolysis plants may compensate for the higher cost of pyrolysis.

Summary of the Invention

The present invention provides a feedstock processing apparatus operable to prepare feedstock for use in a thermochemical decomposition system, which decomposes feedstock produced by the feedstock processing apparatus to produce at least one solid, one liquid and one gas, wherein the feedstock processing apparatus comprises: a slurry processing device, a mixer, a vacuum processor; and a pump; wherein the slurry processing device is operable to mix substantially dry processed material with a fluid and to reduce moisture levels in the mixture of substantially dry processed material and fluid by heating the mixture of substantially dry processed material and fluid; wherein the mixer is operable to receive the reduced moisture level mixture of substantially dry processed material and fluid and to further process the reduced moisture level mixture of substantially dry processed material and fluid to disintegrate the reduced moisture level mixture to produce a fine suspension to pass through the vacuum processor, wherein the vacuum processor is operable to deaerate and remove further moisture from the fine suspension of substantially dry processed material and fluid to produce the feedstock, which can subsequently undergo a decomposition process to produce at least one solid, one liquid and one gas, and wherein the pump is operable to transport the feedstock to the decomposition apparatus.

The mixer may be a high-shear inline mixer, wherein further processing the reduced moisture level mixture of substantially dry processed material and fluid is milling the reduced moisture level mixture of substantially dry processed material and fluid to disintegrate it to a fine suspension.

The feedstock processing apparatus may further comprise a pulverising device and a centrifuge; wherein the pulverising device is operable to pulverise a base material, pre-treat the pulverised base material and remove unwanted materials and/or contaminants from the base material and the centrifuge is operable to separate solids and liquids from the pulverised base material to produce the substantially dry processed material for processing in the slurry processing device.

The centrifuge may be a decanter centrifuge.

The base material may be ferrous or non-ferrous metals, waste tyres, rubber, plastics, etc. The slurry processing device may include a heater operable to heat the mixture of substantially dry processed material and fluid to a temperature of between 80 to 100 degrees centigrade. Alternatively, or in addition, heating the mixture may be done from heat recovered from a component of the downstream decomposition system.

The slurry processing device may include a moisture monitor, operable to determine moisture levels less than 1%.

The fluid used in the slurry processing device may be a hydrocarbon fluid The high shear inline mixer may be adjustable, wherein the size of particulate material produced by the high shear inline mixer can be adjusted to suit the downstream decomposition process.

The vacuum processor may include a series of vacuum tanks through which the substantially dry processed material will pass in sequence on its journey to the downstream decomposition apparatus. Alternatively, or in addition, the vacuum processor may comprise a continuous vacuum tower, through which the substantially dry processed material can pass to be deaerated before being transferred to the decomposition apparatus.

The vacuum processor may further comprise an in-line vacuum pump, which is operable to enhance deaeration and moisture removal from the disintegrated mixture of substantially dry processed material and fluid.

The pump, which is operable to transfer the deaerated and moisture reduced feedstock to the decomposition apparatus may be a reciprocating pump.

The high shear in-line mixer may include a heater and optionally temperature control such that the temperature of the mixture of substantially dry processed material and fluid is maintained at a predetermined temperature. The predetermined temperature may be in the region of 80 degrees centigrade to 100 degrees centigrade.

Description of the Drawings

An embodiment of the present invention will now be described with reference to the accompanying drawings in which: Fig. 1 illustrates a schematic representation of a decomposition system, which includes pre-treatment and feedstock producing apparatus in accordance with the present invention, where the feedstock producing apparatus changes a raw base material to an enhanced feedstock for decomposition; and Fig. 2 illustrates pre-treatment and feedstock producing apparatus in accordance with an example of the present invention.

Description

Fig. 1 is a schematic representation of a complete decomposition system/apparatus 100, which includes an upstream system and process 110, according to an example of the present invention and a downstream fast pyrolysis system and process 120 which uses feedstock material 130 produced from the upstream apparatus and process 110 to produce end products e.g., a solid (charcoal bio char) 140, one bio oil 150 and oil 160 for storage. The structural and functional details of the decomposition apparatus and process are not discussed further other than the re-use of an end product by the upstream apparatus and processes 110. Fast pyrolysis, is the preferred example of a decomposition system and process for use with the pre-treatment and feedstock processing apparatus 110.

Pyrolysis (fast or slow -see table 1 above) is a thermochemical decomposition process of organic base materials at elevated temperatures in the absence of air/oxygen.

At present the fast pyrolysis process is a relatively small scale process because the feedstock material used is typically large solid matter. By adopting the apparatus and process as described herein i.e., to process disintegrated small particle solid material a larger industrial scale fast pyrolysis apparatus and process can be achieved. By adopting a pre-treatment process in accordance with the present invention and as discussed further below, a fast pyrolysis apparatus and process is achieved that produces/yields greater volumes and quantities of end products i.e., solid, oil and gas constituents from an adapted feedstock, which is produced from a raw base material.

The raw base material undergoes an upstream process according to an example of the present invention as illustrated in Fig. 1 and Fig. 2, where the base material is transformed from a solid 30 to a slurry/liquid in absence of air and moisture. The upstream apparatus 110 and the process to produce feedstock 130 i.e., a slurry/liquid in absence of air and moisture from base material 30 is discussed further below.

The analogy of the upstream apparatus 110 and process as illustrated in Fig. 1 and Fig. 2 is similar to the human digestive system where solids and liquids are pulverised and mixed and transformed into a slurry through a chemical and mechanical process.

Earlier attempts to achieve an efficient and cost effective fast pyrolysis apparatus and process have been found to be economically inefficient.

Referring to Fig. 1, the upstream apparatus 110 can be divided into two parts i.e., a raw base material processor 110A and a feedstock processor 110B.

The feedstock apparatus 110B and process is essential to ensure that the configuration and composition of the feedstock 130 is optimised before passing the feedstock 130 to the upstream decomposition apparatus 120 e.g., a fast pyrolysis reactor.

The base material apparatus 110A and process may be required as a pre-treatment step to ensure the material 45 (see Fig. 2) entering the feedstock producing apparatus 110B is adequately configured e.g., particle size, dryness etc. before the material is processed by the feedstock apparatus 1108 and process to further adapt the feedstock for the final decomposition stage.

Referring first to the base material apparatus 110A and process (see Fig. 2), the base material apparatus 110A includes a pulverising device 10 e.g., a shredder or auger, and a decanter centrifuge 20.

The pulverising device 10 pulverises e.g., shreds or crushes the base material 30, which may be general waste, solid rubber, metal, plastic etc. This stage of material processing removes unwanted materials and contaminants from the pulverised base material at this first stage of feedstock processing.

Once pulverised, separated and decontaminated, clean pulverised material 25 passes through a centrifuge 20 i.e., a device that employs a high rotational speed to separate components of different densities. In the present example the centrifuge 20 is a decanter centrifuge, but it should be appreciated a standard centrifuge could be employed.

The decanter centrifuge 20 separates finely distributed solid particles from a suspension by strong centrifugal forces The pulverised material 25 is pumped into the decanter centrifuge 20 through an inlet of a horizontal container, which rotates. The horizontal container comprises a cylindrical part 22 i.e., feed, conveyor and motor and a conical part 24 i.e., the decanter bowl 24. The decanter bowl 24 rotates at a predetermined speed such that the pulverised material 25 rotates within the bowl. Under the influence of centrifugal force solids in the product settle on an inner wall of the decanter bowl 24 due to their higher density i.e., separation of solids and liquids takes place in the conical part 24. The separated solids are conveyed toward the reduced diameter end of the conical shaped decanter bowl 24 Separated liquid is removed e.g., via an internal pump. The liquid e.g., waste water is extracted and decanted to a waste tank 40 and the substantially dry, moisture reduced, solids 45 are passed to the next stage of processing where the feedstock 130 for decomposition is produced.

As noted above the substantially dry, moisture reduced, solids is passed to the feedstock processing apparatus 1108, which is operable to prepare feedstock 130 from the pulverised substantially dry, moisture reduced, solids for use in a decomposition system 120 e.g., a fast pyrolysis process (see Fig. 1).

As illustrated in Fig. 2, the feedstock processing apparatus 1108 includes at least a slurry processing device 50, a high-shear inline mixer 60, a vacuum processor 70; and a pump 80.

The pulverised substantially dry solids 45 are added to the slurry processing device 50 together with a mixing fluid 52, which in the illustrated example is stored in a mixing fluid tank 54. Within the slurry processing device 50, the solids 45 and the mixing fluid 52 are agitated and mixed dynamically and purposefully whilst the mixture is heated to around 80 to 100 degrees centigrade. This process removes moisture from the mixture such that the moisture level is reduced further e.g., to less than 1% moisture.

In the illustrated example the mixture is heated to around 80 to 100 degrees centigrade by heat recovered from a component of the downstream decomposition system. In this example the component of the downstream decomposition system is the pyrolysis reactor 170 (see Fig. 1).

The reduced moisture level mixture of substantially dry processed material and mixing fluid 55 is then transported to the high-shear inline mixer 60.

High shear mixers, also known as rotor-stator mixers and high shear homogenisers, are used to emulsify, homogenise, disperse, grind and/or dissolve immiscible mixtures with components of the same or different phases.

In this example, the purpose of the high shear mixer 60 is to reduce particle size to 1 cm or lower, where the slurry 55 is milled into finer particles in fine suspension i.e., at this stage of the process the material includes a mixture of dry particles 45, mixing fluid 52 and less than 1% moisture content remains.

In the illustrated example, the slurry material 55 being milled in the high shear mixer is also heated to maintain temperature and dryness of the material 55. In this example the temperature within the high shear mixer 60 is maintained at around 80 to 100 degrees centigrade such that the dryness of the material 55 is maintained and to ensure the feedstock material 130 being produced retains a residual heat for the subsequent stages of the pre-treatment process and for the upstream decomposition process 120.

Upon leaving the high shear mixer 60 the disintegrated particulate material 65 passes through a vacuum processor e.g., a vacuum tower 70.

In the illustrated example, a vacuum tower is shown, but it will be appreciated the vacuum processor 70 could be a single vacuum device, a series of vacuum tanks or a vacuum tower as illustrated.

The purpose of the vacuum processor 70 is to deaerate and remove further moisture from the disintegrated material 65 to produce dry feedstock 130, which subsequently undergoes a decomposition process 120 to produce predetermined end products such as one solid, one liquid and one gas.

To enhance the vacuum process, the illustrated example, includes a vacuum pump 90 to remove of air and gas molecules from the sealed area within the vacuum processor 70 thereby ensuring the vacuum processing occurs in an area devoid of moisture, air and/or gas. The vacuum pump 90 ensures this stage of the preparing feedstock 130 is clean and sealed.

Upstream of the vacuum processor 90 and downstream of the decomposition apparatus 120, the feedstock processing apparatus 1108 includes the pump, 80 for example a reciprocating pump, which transports the produced dry and clean fine slurry 65 as feedstock 130 from the vacuum processor 70 to the decomposition apparatus e.g., a pyrolysis reactor 170 (see Fig. 1).

In the illustrated example, the feedstock 130 passes to a pyrolysis reactor 170 and a fast pyrolysis process decomposes the feedstock 130 to produce at least three separate components e.g. solid (charcoal, biochar), liquid and non-condensable gases (H2, CH4, CnHm, CO, CO2 and N). In the illustrated example, the pyrolysis process produces a solid component 140, a bio oil component 150 and an oil product 160.

In the illustrated example, the bio oil component 150 is redirected and re-used by the slurry processing device 50, where the solids 45 and the bio oil component 150 and/or mixing fluid 52 are agitated and mixed dynamically and purposefully whilst the mixture is heated to around 80 to 100 degrees centigrade to remove moisture from the mixture.

The complete process described above and as illustrated in Fig. 1 is to transform a raw base material, in the most effective and efficient manner to produce the desired end products from a decomposition process.

As described above the system redirects and reuses the produced bio oil component in the slurry processing device 50. Additionally, heat recovered from a component of the downstream decomposition system e.g., the pyrolysis reactor 170 is redirected and used in the upstream process to heat the mixture in the slurry processing device.

In summary, using a solid base material 30, as described above, the feedstock producing apparatus and process comprises: * reducing solid base material 30 into a granular or powdered form 45 * creating a slurry 55 by combining the granular or powdered material 45 with a mixing fluid 52, e.g., a medium to light hydrocarbon-based solution/waste oils (vegetable or hydrocarbon based), which can be an end product of the downstream decomposition process; * homogenising 60, dehydrating and deaerating 70 the slurry 55 to produce substantially dry feedstock 130 i.e., containing less than 1% moisture; and * pumping the substantially dry fine particulate feedstock 130, at a predetermined pressure and rate, to a decomposition apparatus 170 e.g. a pyrolysis reactor.

Switching from raw solids to an enhanced and purer fine particulate feedstock for the decomposition process has many benefits. A few examples are as follows: * a continuous process at an industrial scale thereby increasing the volume of end materials produced from the decomposition process; * a reduction (possible elimination) of NOX and SOX gases from the decomposition process; * a reduction (possible elimination) of Oxygen in the end product oil and gas; * re-using end products e.g., bio oil and heat from the decomposition process in the pre-treatment process reduces waste products; * improved downstream decomposition system due to the materials being produced by the upstream process, thereby improving heat transfer from the downstream process resulting an in energy efficient process and system; * improved, high precision control of the feed rate and pressure of the downstream decomposition system.

Other than the recycling of end products from the downstream decomposition process, structural and functional details of the decomposition apparatus and process, for example fast pyrolysis, do not form part of the invention described above and defined in the appended claims.

Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.

Claims (9)

1. CLAIMS1. A feedstock processing apparatus operable to prepare feedstock for use in a thermochemical decomposition system, which decomposes feedstock produced by the feedstock processing apparatus to produce at least one solid, one liquid and one gas, wherein the feedstock processing apparatus comprises: a slurry processing device, a mixer, a vacuum processor; and a pump; wherein the slurry processing device is operable to mix substantially dry processed material with a fluid and to reduce moisture levels in the mixture of substantially dry processed material and fluid by heating the mixture of substantially dry processed material and fluid; wherein the mixer is operable to receive the reduced moisture level mixture of substantially dry processed material and fluid and to further process the reduced moisture level mixture of substantially dry processed material and fluid to disintegrate the reduced moisture level mixture to produce a fine suspension to pass through the vacuum processor, wherein the vacuum processor is operable to deaerate and remove further moisture from the fine suspension of substantially dry processed material and fluid to produce the feedstock, which can subsequently undergo a decomposition process to produce at least one solid, one liquid and one gas, and wherein the pump is operable to transport the feedstock to the thermochemical decomposition apparatus.
2. 2. The feedstock processing apparatus of claim 1, wherein the mixer is a high-shear inline mixer, operable to mill the reduced moisture level mixture of substantially dry processed material and fluid to disintegrate it to a fine suspension.
3. 3. The feedstock processing apparatus of claim 1 or 2, further comprising a pre-treatment apparatus operable to prepare a base material to a predetermined particulate state for delivery to the feedstock processing apparatus.
4. 4. The feedstock processing apparatus of claim 3, wherein the pre-treatment apparatus comprises: a pulverising device and a centrifuge; wherein the pulverising device is operable to pulverise a base material, pre-treat the pulverised base material and remove unwanted materials and/or contaminants from the base material; and the centrifuge is operable to separate solids and liquids from the pulverised base material to produce the substantially dry processed material for processing in the slurry processing device.
5. 5. The feedstock processing apparatus of claim 4, wherein the centrifuge is a decanter centrifuge.
6. 6. The feedstock processing apparatus of any preceding claim, wherein the slurry processing device includes a heater operable to heat the mixture of substantially dry processed material and fluid to a temperature of between 80 to 100 degrees centigrade.
7. 7. The feedstock processing apparatus of any preceding claim, wherein heat recovered from the decomposition system is operable to heat the mixture of substantially dry processed material and fluid to a temperature of between 80 to 100 degrees centigrade.
8. 8. The feedstock processing apparatus of any preceding claim, wherein the slurry processing device includes a moisture monitor, operable to determine moisture levels less than 1%.
9. 9. The feedstock processing apparatus of any preceding claim, wherein the fluid used in the slurry processing device is a hydrocarbon fluid 10. The feedstock processing apparatus of any of claims 2 to 9, wherein the high shear inline mixer is adjustable, wherein the size of particulate material produced by the high shear inline mixer can be adjusted to suit the downstream decomposition process.11. The feedstock processing apparatus of any preceding claim, wherein the vacuum processor includes a series of vacuum tanks through which, in use, the substantially dry processed material passes in sequence on its journey to the downstream decomposition apparatus.12. The feedstock processing apparatus of claims 1 to 10, wherein the vacuum processor comprises a continuous vacuum tower, through which the substantially dry processed material can pass to be deaerated before being transferred to the decomposition apparatus.13. The feedstock processing apparatus of any preceding claim, wherein the vacuum processor further comprises an in-line vacuum pump, which is operable to enhance deaeration and moisture removal from the disintegrated mixture of substantially dry processed material and fluid.14. The feedstock processing apparatus of any preceding claim, wherein the pump is a reciprocating pump.15. The feedstock processing apparatus of any of claims 2 to 14, wherein the high shear in-line mixer includes a heater and optionally temperature control such that the temperature of the mixture of substantially dry processed material and fluid is maintained at a predetermined temperature.16. The feedstock processing apparatus of claim 15, wherein the predetermined temperature is in the region of 80 degrees centigrade to 100 degrees centigrade.