Pyrolysis chamber and pyrolysis apparatus

Abstract

A pyrolysis chamber comprising: a reaction chamber; a grate arranged for the support of pyrolysis materials; a hinge connecting the grate to the lower wall of the reaction chamber, wherein the grate opens downwardly; and a catch mechanism for holding the grate in a horizontal position, wherein said catch mechanism comprises a sacrificial catch comprising a combustible material. The pyrolysis chamber may be tubular, cylindrical, a hexagonal prism or cuboid shaped. The chamber may have a sacrificial liner. The chamber may have an enclosure wall and air gap surrounding the chamber wall. The sacrificial catch may be biomass or the same or similar material to that which is being pyrolyzed.

Description

Field of Invention The present invention generally relates to the field of pyrolysis apparatus for use in carbon capture. Background The pervasive use of fossil fuels as the primary energy source for most transportation, space heating and industrial activity has led to the release of increasingly large amounts of carbon dioxide into the atmosphere. The resulting increase in CO2 concentration in the atmosphere is believed by the climate research community to be a primary driver of global warming. Because of the potentially dire economic and human consequences of global warming, extensive efforts are being made to reduce carbon from the atmosphere. Pyrolysis is a method utilised to transform carbon based substances into refined stabilised forms of carbon, whereas full combustion tends to release the CO2 and other carbon compounds back into the atmosphere. Due to the nature of pyrolysis, high temperatures and technological application restrict adoption of the full potential of pyrolysis. As a result, pyrolysis is either used in large scale infrastructure environments or in heavy semi-industrious applications. Major improvements have been made to domestic stove technology that utilise techniques borrowed from the pyrolysis method, but many fall short of successfully capturing the carbon that is often released into the atmosphere. Simplifying the mechanism for the release of the captured carbon, would open up the technology to a broader range of market, enabling carbon capture within the realm of micro-gasification or for use by the general domestic society. Thermal degradation and heat stresses have a major impact on pyrolysis vessels particularly at the later stages of combustion. To compensate dealing with the high temperatures experienced in pyrolysis, materials employed tend to be of substantial dimensions, which results in an increase of size, weight and cost of the final product. Simplifying the construction can aid in this respect, but often results in human interaction to extract the desired product, involving an experienced understanding of the dynamics of the process. The apparatus described herein involves a simple release mechanism that is directly related to the pyrolysis process, thereby mitigating any reliance on sensors or other complex devices to make way for the release of valuable carbon by-products. The apparatus allows for the extraction of pyrolyzed biomass from a thermal reaction (or decomposition) chamber. The apparatus incorporates the use of a sacrificial piece of substantially rigid organic material and the process of pyrolysis itself to initiate the release mechanism at the necessary time of batch completion. As the course of pyrolysis progresses, it combusts the substantially rigid organic piece, undermining its integral strength to the point at which the threshold of the chamber collapses under the mass of the pyrolyzed biomass. Also described herein, is a method for extracting pyrolyzed biomass from a batch pyrolysis vessel for successful carbon capture. The apparatus and method described herein mitigates the need for human intervention at the appropriate time as well as mitigating other more complex methods of extraction. Prior art systems and techniques commonly involve increased technological solutions such as sensors and electro mechanical systems to carry out the task, which involve high temperature stresses, increased cost, additional weight and size of product. Furthermore, variable heat conditions cause heat stresses and fatigue which can impact the form of the model, leading the mechanism to fail. By taking advantage of this property, a sacrificial portion of similar biomass feedstock is used in place of a crucial part of the mechanism prior to fuelling the feed chamber. As the pyrolysis process takes place the combustion reaches the stage where completion of the charcoal production process compromises the sacrificial portion, releasing the mechanism that contains the by-product emptying the contents into a secondary containment. In this manor an elegant and simple solution provides the improved usability, without complication or over engineering. Although micro-gasification systems have been in development for some decades now, many of them fail to provide convenient extraction of the stabilised carbon by-product. By overcoming this barrier, utility of this technology can benefit micro and domestic scale applications. As a result more carbon can be usefully captured providing a cleaner atmosphere for local communities. Summary of the Invention According to one aspect of the present invention there is provided a pyrolysis chamber for use in a pyrolysis apparatus comprising a chamber arranged for the receipt of material for pyrolysis; provided to a lower portion of said chamber, a grate arranged for the support of said material for pyrolysis, wherein said grate is in hinged relationship to said lower portion of the chamber and arranged for downwards hinged opening; and a catch mechanism for catching the grate in a catching position in which said downwards hinged opening is prevented, wherein said catch mechanism comprises a sacrificial catch comprising a combustible material. There is provided a pyrolysis chamber for use in a pyrolysis apparatus. The pyrolysis chamber comprises a reaction chamber arranged for the receipt of material for pyrolysis. The reaction chamber is suitably formed of a material that may withstand the high temperatures encountered in a pyrolysis process. In embodiments, suitable materials for the reaction chamber include metals (e.g. iron or steel) or ceramics. Suitably, the reaction chamber defines an inner wall or walls and an outer wall or walls. In embodiments, the reaction chamber is of tubular form. In other embodiments the reaction chamber is of cylindrical, cuboid or hexagonal prism shape. In embodiments, the reaction chamber is provided with a sacrificial liner at the inner wall thereof. In embodiments, the reaction chamber is provided with an enclosure wall separated by an air gap from the outer wall of the chamber. In embodiments, the reaction chamber is provided with an enclosure with enclosure wall or walls separated by an air gap from the outer wall or walls of the chamber. At a lower portion of the reaction chamber (e.g. at the bottom of the wall or walls thereof), there is provided a grate arranged for the support of the material for pyrolysis. The grate is in hinged relationship to the lower portion of the reaction chamber and arranged for downwards hinged opening relative thereto. The grate is suitably formed of a material that may withstand the high temperatures encountered in a pyrolysis process. In embodiments, suitable materials for the grate include metals (e.g. iron or steel) or ceramics. There is also provided a catch mechanism for catching the grate in a catching position, in which said downwards hinged opening of the grate relative to the reaction chamber is prevented. In the catching position, the grate typically adopts a generally horizontal orientation. The catch mechanism comprises a sacrificial catch comprising a combustible material. In embodiments, the sacrificial catch is rigid in nature. In embodiments, the sacrificial catch has the form of a latch, peg or a wedge. In embodiments, the sacrificial catch is of elongate form. In embodiments, the sacrificial catch is formed of biomass (e.g. wood or compressed sawdust, natural fibres or wood chippings). In embodiments, the sacrificial catch is formed of the same or similar material as the material for pyrolysis. According to another aspect of the present invention, there is provided a pyrolysis apparatus comprising the pyrolysis chamber herein and a collection chamber for receipt of pyrolyzed material. In embodiments, the collection chamber locates underneath the reaction chamber and the hinged grate opens downwards into the collection chamber. Thereby, pyrolyzed material may be transferred into the collection chamber. Brief Description of the Drawings Figure 1 shows a pyrolysis chamber herein with the grate in the latching position, in which material for pyrolysis is supported by the grate; Figure 2 shows a pyrolysis chamber herein with the grate in the latching position, in which material for pyrolysis is supported by the grate and in which the sacrificial latch is being combusted during a pyrolysis process; and Figure 3 shows a pyrolysis chamber herein with the grate released from the latching position following combustion of the sacrificial latch, and in which pyrolyzed material is no longer supported by the grate and falls downwards. Detailed Description of the Drawings ............................................................................................................................................................'*......................................................................................................................................................................................................... Fig 1. Shows a cross sectional diagram of Fixed-bed Up-draft batch pyrolysis chamber, loaded with Biomass and pyrolysis action at sub critical point. Fig 2. Shows a cross sectional diagram of Fixed-bed Up-draft batch pyrolysis chamber, loaded with Biomass and pyrolysis action at critical point, and the sacrificial piece being undermined. Fig 3. Shows a cross sectional diagram of Fixed-bed Up-draft batch pyrolysis chamber, with pyrolysis action post critical point, and the desired product being released by gravity, the fixed-bed grate fully open and the sacrificial piece fully compromised. The apparatus and method presented thus far is appropriate to Fixed Bed Up-draft Batch pyrolysis equipment. These systems comprise of a pyrolysis chamber, expanse chamber, heat riser / feed chute. The pyrolysis chamber tends to be of cylindrical shape, sometimes with a sacrificial liner on the inside wall and often accompanied with an outer wall separated by an air gap. A fixed grate is positioned at the bottom of the chamber, sometimes, this part is also sacrificial and is coupled loosely. In this instance it is hinged and is intended to be made of material durable enough to withstand the heat stresses applied to it during operation for a substantial lifetime. Opposed to the hinge mechanism is a catch mechanism designed to be impregnated with a sacrificial portion of similar biomass at location 1, indicated in Fig 1 &2. This piece fixes the grate in the closed position to the pyrolysis chamber or other supporting structure. The sacrificial portion of similar biomass is located prior to loading of the chamber with feedstock. Dried biomass of particular proportions are loaded into the top of the chamber before igniting. The biomass is held in place by the fixed-bed grate at the bottom of the chamber. The feedstock is ignited at the top either directly or indirectly using an intermediary medium. Once ignited the dry biomass combusts the solid material releasing flammable gases and liquids. Secondary air is injected into the area above the flames in the expansion chamber where the oxygen reacts with the flammable substances which produce more complete combustive reactions. The heat produced by this reaction consequentially breaks down more of the biomass releasing further flammable compounds. Primary air supplied through the grate, drives up, hence the term Up-draft, through the biomass starving the full combustion of biomass of oxygen and hence gives the desired pyrolysis effect. This process continues until all the biomass has charred. At this point we reach the critical stage at Fig 2. where the sacrificial portion of similar biomass becomes fully compromised. With other designs of this type of device, human intervention is often the necessary requirement to extract the desired by-product which is not a simple procedure. Alternative options tend to involve the use of high temperature resistant sensors and mechanisms. Without these interventions the solid char by-product would continue to fully combust down to ash, reducing the product to a sub optimum product. The intervention proposed in this document, allows for the process to be interrupted by the removal of the char by release of the grate. This is visually represented in Fig. 3. One may observe in Fig. 3, that sacrificial portion indicated at positions (1) has been fully compromised. Fixed-bed grate (no. 2) has opened at hinge (no. 3) allowing for the char (no. 4) to freely release into a quench chamber or otherwise be extinguished to halt further heat de-combustion. This mechanism can be scaled up or down depending on the feed utilised and requirements of the operation. Given such objectives, the dimensions of the sacrificial portion would need to be calculated as well as the size and position of the mechanism. Some examples are given in subsequent Figures. It is understood that the invention is not limited to the specific details described herein which are given as an example only and that various modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A pyrolysis chamber for use in a pyrolysis apparatus comprisinga reaction chamber arranged for the receipt of material for pyrolysis;provided to a lower portion of said reaction chamber, a grate arranged for the support of said material for pyrolysis, wherein said grate is in hinged relationship to said lower portion of the reaction chamber and arranged for downwards hinged opening;and a catch mechanism for catching the grate in a catching position in which said downwards hinged opening is prevented,wherein said catch mechanism comprises a sacrificial catch comprising a combustible material.

2. A pyrolysis chamber according to claim 1, wherein the reaction chamber is of tubular form3. A pyrolysis chamber according to claim 1, wherein the reaction chamber is of cylindrical,cuboid or hexagonal prism shape.

4. A pyrolysis chamber according to any of claims 1 to 3, wherein the reaction chamber is provided with a sacrificial liner at an inner wall thereof.

5. A pyrolysis chamber according to any of claims 1 to 4, wherein the reaction chamber is provided with an enclosure wall separated by an air gap from an outer wall of the chamber.

6. A pyrolysis chamber according to any of claims 1 to 5, wherein in the catching position, the grate adopts a generally horizontal orientation.

7. A pyrolysis chamber according to any of claims 1 to 6, wherein the sacrificial catch is of rigid form.

8. A pyrolysis chamber according to claim 7, wherein the sacrificial catch has the form of a latch, peg or a wedge.

9. A pyrolysis chamber according to either of claims 7 or 8, wherein the sacrificial catch is of elongate form.

10. A pyrolysis chamber according to any of claims 1 to 9, wherein the sacrificial catch is comprised of biomass.

11. A pyrolysis chamber according to any of claims 1 to 10, wherein the sacrificial catch is formed of the same or similar material as the material for pyrolysis.

12. A pyrolysis apparatus comprising the pyrolysis chamber according to any of claims 1 to 11 and a collection chamber for receipt of pyrolyzed material.

13. A pyrolysis apparatus according to claim 12, wherein said collection chamber locates underneath the reaction chamber and the grate hinges open downwards into the collection chamber.

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