WO2022253366A1

WO2022253366A1 - Method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane and apparatus for implementing the method

Info

Publication number: WO2022253366A1
Application number: PCT/CZ2022/050035
Authority: WO
Inventors: Ondřej Němček; Marcel MIKESKA; Jan Kielar; Tomáš NAJSER
Original assignee: Vysoká Škola Báňská - Technická Univerzita Ostrava
Priority date: 2022-03-28
Filing date: 2022-03-30
Publication date: 2022-12-08
Also published as: CZ2022136A3; CZ310023B6

Abstract

The object of the invention is a method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane and an apparatus for implementing said method. According to the method, the biomass is first introduced into at least one torrefaction reactor (3), where it is subject to torrefaction at a temperature of 50 °C to 400 °C and a pressure of -50 kPa to +100 kPa, and then it is introduced into at least one pyrolysis reactor (7), where it is subject to pyrolysis at a temperature of 400 °C to 800 °C and a pressure of -50 kPa to +100 kPa to produce pyrolysis gas. During pyrolysis, a catalyst selected from the group consisting of nickel nanoparticles, copper nanoparticles, cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles and rhodamine 6G, or any combination thereof, is added to the biomass. Alternatively or in addition, before pyrolysis, preferably during torrefaction and/or after torrefaction outside the torrefaction reactor (3), a catalyst selected from the group consisting of cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles, rhodamine 6G, and a combination of nickel and cobalt nanoparticles, or any combination thereof, is added to the biomass. The addition results in a methane-enriched gas with a methane content of 10 to 60 vol. %. The present invention further relates to a use of said catalysts for enriching a gas produced by torrefaction and pyrolysis of biomass with methane, a computer program [product], a computer-readable medium and a data signal carrier.

Description

Method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane and apparatus for implementing the method

The present invention relates to a method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane, and to an apparatus for implementing said method. The present invention also relates to a use of catalysts for the enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane, a computer program operating said device and a computer readable medium or a data signal carrier with said computer program.

The current state of knowledge in the field of thermal processing of alternative materials and biomaterials based on the principles of pyrolysis, torrefaction and gasification is at a good level. These technologies are relatively well known and are operated in industrial production and experimental facilities.

In general, the technologies of torrefaction and pyrolysis of material, which is the thermal treatment of input material in an inert atmosphere, i. e. heating the material without access to air, can be divided into three basic types according to the temperature of the process - low-temperature pyrolysis, also called torrefaction (roasting), medium-temperature pyrolysis and high-temperature pyrolysis. Each of these process types is designed to produce three fractions. Depending on the process temperature, it is then possible to obtain mainly gaseous, liquid and solid fractions in different proportions.

Procedures are known for conducting a process to recover the output products - gaseous, liquid and solid fractions through the above-mentioned processes. The quantity, quality and composition of the output products are influenced by process control. There are ways of controlling the process and influencing the properties of the products by varying the process temperature, the residence time of the material in the torrefaction and pyrolysis apparatus, the use of a particular type of feedstock of known composition.

In the field of design and technology, there are known devices with different types of reactor having a stationary layer (batch), being continuous (flow), where the input material is fed into the technology, where continuous processing and continuous production of products occurs over time. There are also different types of integration into the technological process, where storage tanks and filling and dosing devices are installed before the actual input to the technology, followed by filtration and separation columns and storage tanks for storing gaseous, liquid and solid products after the output from the technology. From the design point of view, it is always a device that comprises several main parts: 1. the hopper and storage part, where the material is stored and transported to the active part itself, where the process of torrefaction or pyrolysis takes place; 2. the reactor, be it batch, gravity, forced feed with a grate or screw, heated electrically, by flame or flue gas; 3. the outlet part after the reactor, where the solid residue and gas are separated, aftercooling and liquefaction of part of the gas to obtain the liquid fraction and possible further filtration of these products.

The international patent application WO 2017217573 A1 discloses a method of and apparatus for producing carbonized pellets with a high carbon content and high calorific value. Carbonization is a type of pyrolysis that leaves primarily a residue with high carbon content. The above production method includes the step of preparing wood chips, the step of torrefying wood chips in an oxygen-free atmosphere, the step of grinding the torrefied wood chips into a powder form, the step of forming a mixture of powdered torrefied wood chips, a binder, a nanocatalyst solution and other additives into pellets, and the step of carbonizing the pellets. A torrefaction reactor in the torrefaction step produces torrefaction gas at a temperature of 180 to 400 °C and a pressure of 0 to -0.1 kPa, which is fed to a carbonisation reactor, and the carbonisation reactor in the carbonisation step at a temperature of 200 to 500 °C further produces carbonisation gas, which is fed together with the torrefaction gas to a combustion chamber for heat recovery and its return to the system. The torrefaction gas is a mixture of carbon monoxide, carbon dioxide, hydrogen and hydrocarbons, in particular methane and/or acetylene. The carbonization gas at the outlet of the carbonization reactor includes hydrocarbons, in particular methane and/or acetylene, without specifying the specific methane content. The nanocatalysts used include nanoparticles of nickel, copper, iron, zinc, magnesium, and/or aluminium, particularly at a content of 0.01 to 5 parts by weight (e. g. 0.1 to 50 mg) relative to 100 parts by weight (e. g. 1 g) of powdered torrefied wood chips.

The Chinese patent application CN 109974002 A discloses a waste treatment process with pyrolysis reactors and combustion chambers arranged in parallel, producing dioxin-free pyrolysis gas for heat and energy recovery. The parallel arrangement provides a larger surface area for heat exchange and uniform heat transfer.

The European patent application EP 2428546 A1 discloses a process for generating solid or semi-solid biofuel by rapid pyrolysis of biomass with three, liquid bed reactors connected in series: a preheating reactor, a pyrolysis reactor and a combustion reactor. The resulting pyrolysis gas includes mainly carbon monoxide, carbon dioxide and hydrogen.

Apart from the one-step addition of copper or nickel nanoparticles to torrefied biomass before carbonization according to WO 2017217573 A1, the application of additives to biomass for processing by torrefaction and pyrolysis in order to change the composition and proportion of the final gas produced, with an emphasis on the enrichment of this gas with methane, is currently unknown.

At present, there is also no known solution for multi-sectional connection of torrefaction or pyrolysis reactors in parallel or in series so that it is possible to dose the same biomass to all such reactors simultaneously, while taking advantage of different physical or chemical conditions and other parameters operating in each reactor. With this connection and continuous analysis followed by feedback control of each reactor involved, it is possible to perform targeted control to change the desired composition of the final gas produced.

A first object of the invention is to provide a method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane to a final volume of 10 to 60 vol. % of methane.

The above-mentioned aim is achieved by a method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane according to

independent claims

1 and 2. In this method, the biomass is introduced into at least one torrefaction reactor, torrefied at a temperature of 50 °C to 400 °C (e. g. 200 °C to 250 °C for grass and 200 °C to 350 °C for woody plants) and a pressure of -50 kPa to +100 kPa in the torrefaction reactor, and further introduced into at least one pyrolysis reactor and pyrolyzed at a temperature of 400 °C to 800 °C and a pressure of -50 kPa to +100 kPa in the pyrolysis reactor. The residence time of the biomass in the torrefaction reactor or the pyrolysis reactor is approximately 30 minutes to 2 hours. At pressures of -50 kPa to 0 kPa, the release of volatile and low boiling point components is more intense and at pressures of 0 kPa to +100 kPa, complex hydrocarbon compounds are broken down to simpler ones, e. g. to methane. Conventional pyrolysis under the above conditions and without the addition of a catalyst produces approximately 10 to 20 vol. % of methane in the pyrolysis gas for grass, approximately 15 to 30 vol. % of methane for woody plants and approximately 10 to 40 vol. % of methane for other waste production.

In one embodiment according to claim 1, the addition of a catalyst selected from the group consisting of nickel nanoparticles, copper nanoparticles, cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles, and rhodamine 6G, or any combination thereof, to the biomass is carried out during pyrolysis in the pyrolysis reactor to produce a methane-enriched pyrolysis gas with a methane content of 10 to 60 vol. %. The addition during pyrolysis, i. e. during the ongoing pyrolytic processing of the biomass, ensures a higher efficiency of the catalysts, whose catalytic activity may be significantly reduced when exposed to the full-length torrefaction or pyrolysis conditions. This fouling effect can be observed especially for catalysts containing noble metals, i. e. copper, platinum, palladium, rhodium, ruthenium and mercury. For economic reasons it is advisable to use these catalysts only during pyrolysis.

In another embodiment according to claim 2, the addition of a catalyst selected from the group consisting of cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles, rhodamine 6G, and a combination of nickel and cobalt nanoparticles, or any combination thereof, to the biomass is carried out before pyrolysis, preferably during torrefaction and/or after torrefaction outside the torrefaction reactor, to produce a methane-enriched pyrolysis gas with a methane content of 10 to 60 vol. %. The addition during torrefaction, i. e. during the ongoing torrefaction of the biomass, and/or between torrefaction and pyrolysis, allows for a longer contact time between the biomass and the catalyst for the whole or almost the whole length of the torrefaction and pyrolysis process, and therefore also allows for methane enrichment of the resulting gas, despite the reduction in catalytic activity of some catalysts or the economic disadvantages mentioned above.

The primary purpose of these catalysts is to convert the CO₂ and H₂ produced during torrefaction and/or pyrolysis of biomass to a higher total methane content in the resulting pyrolysis gas. CO₂ is a non-flammable gas, which is also undesirable in terms of emissions and carbon footprint, and H₂, although flammable, causes detonation and unstable combustion, thus is undesirable in a conventional energy cycle or other process. Without the use of a catalyst, the resulting methane content of the pyrolysis gas would depend only on the feed material and this gas could not be further enriched.

The advantages of both methods can be combined, and the addition can be carried out with the catalyst both before and during pyrolysis.

In a preferred embodiment, the catalyst is deposited on the surface of a carrier selected from the group consisting of aluminosilicate, aluminium oxide, magnesium oxide, titanium dioxide, cerium dioxide, zirconium dioxide, or any combination thereof. The catalyst may be applied to the surface of the carrier by a wet impregnation method.

Specific exemplary catalyst formulations A-H and their advantages are given below:

A: a mixture of 12.0 to 13.0 wt. % of nickel nanoparticles and 1.5 to 2.5 wt. % of cobalt nanoparticles relative to the carrier, preferably a mixture of 12.5 wt. % of nickel nanoparticles and 2.0 wt. % of cobalt nanoparticles relative to the carrier - the advantage being low cost, usability before and during pyrolysis and enrichment of the resulting gas by approximately 1 to 5 vol. % of methane using any biomass;
B: a mixture of 7.0 to 8.0 wt. % of nickel nanoparticles, 7.0 to 8.0 wt. % of cobalt nanoparticles and 0.1 to 0.5 wt. % of ruthenium nanoparticles relative to the carrier, preferably a mixture of 7.5 wt. % of nickel nanoparticles, 7.5 wt. % of cobalt nanoparticles and 0.25 wt. % of ruthenium nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 10 to 15 vol. % of methane using any biomass;
C: a mixture of 10.0 to 11.0 wt. % of molybdenum nanoparticles and 1.0 to 2.0 wt. % of mercury nanoparticles relative to the carrier, preferably a mixture of 10.5 wt. % of molybdenum nanoparticles and 1.5 wt. % of mercury nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 1 to 5 vol. % of methane using any biomass;
D: 0.1 to 1.0 wt. % of platinum nanoparticles relative to the carrier, e. g. 0.5 wt. % of platinum nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 10 to 20 vol. % of methane using any biomass;
E: 0.1 to 2.0 wt. % of copper nanoparticles relative to the carrier, e. g. 0.5 to 1.5 wt. % of or 1.0 wt. % of copper nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 1 to 5 vol. % of methane using any biomass;
F: 0.1 to 2.0 wt. % of palladium nanoparticles relative to the carrier, e. g. 0.5 to 1.5 wt. % of or 1.0 wt. % of palladium nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 10 to 20 vol. % of methane using any biomass;
G: 0.1 to 2.0 wt. % of rhodium nanoparticles relative to the carrier, e. g. 0.5 to 1.5 wt. % of or 1.0 wt. % of rhodium nanoparticles relative to the carrier - the advantage being enrichment of the resulting gas by approximately 10 to 20 vol. % of methane using any biomass;
H: 0.05 to 0.30 wt. % of rhodamine 6G relative to the carrier, e. g. 0.10 to 0.20 wt. % of rhodamine 6G relative to the carrier, preferably also in combination with experimental conditions of ionizing radiation, ultrasound and magnetic field - the advantage being enrichment of the resulting gas by about 2 to 5 vol. % of methane using any biomass.

In the case of formulations B-H, it is advantageous to add the catalyst to them only during pyrolysis, because the rhodamine 6G or metals contained in these catalysts may be partially degraded by the pyrolysis process and lose their catalytic activity (the presence of various tars causes the formation of a coating on their surface and prevents gas access to the catalyst), which will reduce the resulting methane content in the pyrolysis gas. During pyrolysis, this may mean, for example, the first third or first half of the pyrolysis reactor relative to the flow of material through the reactor. If these formulations are also added before pyrolysis for further methane enrichment, e. g. during torrefaction and/or between torrefaction and pyrolysis, it may be advisable to add the catalyst to them also during pyrolysis for the above reasons.

For formulation A, a similar phenomenon to other formulations can be observed, but the combination of nickel and cobalt nanoparticles is not as economically costly to replenish as for the noble metals, and therefore this formulation can be used in any method step.

For all formulations A-H, and especially for formulation C, it is necessary to ensure the disposal of the pyrolysis residue as hazardous waste after the addition. For all formulations A-H, the catalysts may be dissolved in an aqueous solution.

The amount of catalyst deposited on the carrier can be 0.1 to 5 mg per 1 g of biomass, where the reference biomass weight is the weight of biomass before entering the torrefaction reactor for addition before pyrolysis and the weight of biomass before entering the pyrolysis reactor for addition during pyrolysis.

In a preferred embodiment, the torrefaction of the biomass may be carried out in at least two torrefaction reactors arranged in series or in parallel or in series-parallel to each other. Similarly, pyrolysis of the torrefied biomass may be carried out in at least two pyrolysis reactors arranged in series or in parallel or in series-parallel to each other. In each reactor, individual process conditions can be set in a controlled manner to thermally treat the biomass and enrich the pyrolysis gas with methane. The individual reactors are connected by sensors with a control unit.

In a preferred embodiment, the biomass may comprise grass, woody plants, hay, straw, bran, husks, leaves and/or agricultural production waste.

In a preferred embodiment, the methane content of the pyrolysis gas, or also the torrefaction gas, can be analysed continuously in real time using an analyser (e. g. a gas chromatograph, a non-dispersive infrared sensor, a thermal conductivity detector, a flame ionization detector, a mid-infrared sensor, or a combination thereof, or any other suitable sensor for analysing the composition of the methane-containing gas) in order to generate input data which are evaluated by a control unit. The control unit subsequently feedback-modifies any of the process parameters, i. e. the temperature and/or pressure and/or residence time of the biomass and/or the amount of biomass introduced and/or the ratio of the different biomass components in at least one torrefaction reactor and/or in at least one pyrolysis reactor and/or the amount of the added catalyst.

The control unit therefore regulates the operating variables for each torrefaction and pyrolysis reactor separately based on the analysis of the resulting gas and its composition. The entire process can therefore be controlled, and the gas composition can be influenced to the desired value, e. g. by disconnecting one of several reactors, changing the temperatures and partial operating parameters of individual reactors etc., and injecting catalysts, additives and other chemical reagents and substances during the process at a precisely defined time and place. By involving multiple reactors, the output products and their parameters can then be stabilised or influenced, especially the resulting gas produced, in order to change the ratio composition and formation of methane components at the expense of CO₂ and H₂.

A second object of the invention is to provide an apparatus for implementing the method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane to a final volume of 10 to 60 vol. % of methane.

The above-mentioned aim is achieved by an apparatus for implementing the above-mentioned method, comprising:

at least one torrefaction reactor having a biomass inlet and torrefied biomass outlet,
at least one pyrolysis reactor having a torrefied biomass inlet, a pyrolysis residue outlet and a methane-enriched pyrolysis gas outlet,
an addition device for adding a catalyst to the biomass, wherein the addition device is arranged in the torrefaction reactor as an injection device (e. g. as at least one nozzle within the torrefaction reactor) and/or in the pyrolysis reactor as an injection device (e. g. as at least one nozzle within the pyrolysis reactor) and/or between the torrefaction reactor and the pyrolysis reactor outside both reactors (e. g. as a spraying device or a mixing device),
an analyser for the analysis of the methane content of the torrefaction gas and/or for the analysis of the methane content of the pyrolysis gas to generate input data; and
a control unit adapted to evaluate the input data and to a feedback modification of the conditions in the torrefaction reactor, the addition device and/or the pyrolysis reactor.

The torrefaction as well as the pyrolysis reactor may preferably be a reactor with a generally known screw feeder. By controlling the speed of the screw, the residence time of the biomass in the reactor can be modified, which is typically 30 minutes to 2 hours. These reactors may be provided with check valves and control valves in order to achieve the desired pressures. The atmosphere in the reactors is essentially oxygen-free during torrefaction and pyrolysis.

The injection nozzles in the reactors can be arranged at regular intervals along the length of the reactor and can be used to sprinkle or spray the biomass as it passes through the reactor. During both torrefaction and pyrolysis, thermal degradation phenomena occur gradually, i. e. with increasing temperature and residence time in the reactor. Based on the measurements, it can be concluded that the material is first dried and initially heated throughout the volume, followed by evaporation of easily volatile substances, and then followed by disruption of more complex bonds of the material and their splitting, where the gaseous substances formed can also further influence the subsequent thermal degradation process (material decomposition). Thus, by injecting catalysts at a specific point and time in the reactor, the thermal degradation process can be influenced, and the resulting content of the produced gas can be changed again.

In a preferred embodiment, the device may comprise at least two torrefaction reactors arranged in parallel or in series to each other. Similarly, the device may comprise at least two pyrolysis reactors arranged in parallel or in series to each other.

A third object of the invention is to provide a novel use of any of the catalysts according to the formulations A-H for the enrichment of gas produced by the torrefaction and pyrolysis of biomass with methane.

A fourth object of the invention is to provide a computer program [product] comprising instructions that cause the apparatus comprising a control unit to execute the steps of the method comprising feedback modification of at least one process parameter based on the analysis of the methane content of a gas produced by torrefaction and/or pyrolysis.

A fifth object of the invention is to provide a computer-readable medium having stored thereon the above-mentioned computer program [product], or a data signal carrier carrying the above-mentioned computer program [product].

The nature of the invention is further explained by examples of its embodiments, which are described using the accompanying drawings, where:

Fig.1

schematically shows an example apparatus for the enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane.

Examples

The embodiments herein illustrate exemplary embodiments of the invention, which, however, have no limiting effect in terms of the scope of protection.

One exemplary embodiment is the method according to claim 3 with combined addition during torrefaction, between torrefaction and pyrolysis, and during pyrolysis, as shown in . However, the skilled person will recognize that the individual addition steps may also be used only during torrefaction or only between torrefaction and pyrolysis (see claim 2) or only during pyrolysis (see claim 1), or may be combined in various ways, e. g. as an addition during torrefaction and between torrefaction and pyrolysis, or as an addition during torrefaction and during pyrolysis, or as an addition between torrefaction and pyrolysis and during pyrolysis.

In this example embodiment, also illustrates an apparatus for implementing this method with torrefaction reactors 3 and pyrolysis reactors 7 arranged in parallel. However, the skilled person will recognize that only at least one torrefaction reactor 3 and at least one pyrolysis reactor 7 are sufficient for the nature of the invention. Also, any two torrefaction and/or

pyrolysis reactors

3 , 7 can be arranged in series.

According to , the input material at the beginning of the method is e. g. waste material that would otherwise be unusable (plastics, paper, chipboard), fuel with low calorific value that is not convenient to burn or otherwise be used directly for energy (low-energy coal/chips, residues from fuel production and industrial plants) or biomass with low calorific value (agricultural production residues, wood waste, bark, food residues, sludge, hay, straw, bran, rice husks, leaves, etc.). This input material is placed in a hopper 1 which can be closed (e. g. a top-filled container, silo). The material is successively removed, preferably from the bottom, by means of a conveyor in the required quantity and is conveyed to the torrefaction reactor 3 . The hopper 1 may be filled with an inert gas to ensure that no oxygen is present in the process from the hopper 1 to the final outlet, thus preventing the material from burning throughout the processing. Thus, the material proceeds through the torrefaction reactor 3 , where it undergoes the torrefaction process with the addition of a catalyst by means of a first addition device 4 , and its physical-chemical properties are changed. The material is dried, and a portion of the material is released in the form of a gas of a certain composition, which depends on the process parameters and the composition of the input material. In general, these are mainly CO, CO₂, smaller amounts of CH₄ and H₂, and possibly other small amounts of other gases and hydrocarbons. Thus, at the outlet of the torrefaction reactor 3 , it is possible to separate the solid residue and the gaseous fraction released from the material by the torrefaction process, which can be diverted for further processing.

The solid residue is the input material for the subsequent pyrolysis treatment, the material having acquired new properties and having gained energy value by torrefaction. The energy gain consists in the so-called carbonisation, where the total carbon content of the material is increased, the material is dried and the structure of the material is partially changed, thus, for example, acquiring hydrophobic properties. The total energy value of the processed material is higher than that of the input material. The torrefied material may be subject to further addition in an intermediate step by means of a second addition device 6 , which may take the form of sprinkling the material with a catalyst in liquid form or physical mixing of the torrefied material with the catalyst. Subsequently, the torrefied material can be further processed, for example, into pellets or briquettes for better transport and handling.

The torrefied material then proceeds to the pyrolysis process, where the material is subject to different process conditions than during torrefaction - in particular, a higher temperature, e. g. in combination with a controllable residence time of the material in the pyrolysis reactor 7 , where it undergoes the pyrolysis process with the addition of a catalyst by means of a third addition device 8 . Again, the material gains energy value to form a pyrolysis solid residue, pyrolysis liquid and pyrolysis gas containing CO, CO₂, H₂ and CH₄ and other gases. The catalyst is designed to enrich the pyrolysis gas with methane at the expense of the CO₂ and H₂ produced.

After the output from both the torrefaction reactor 3 and the pyrolysis reactor 7 , the content of the torrefaction gas or pyrolysis gas is analysed in real time using a first or

second analyser

5 , 9 , e. g. a Syngas analyser 3100, Siemens FIDAMAT 6, Siemens CALOMAT 6, Siemens ULTRAMAT 6 and/or Master GC. The generated input data are evaluated by the control unit 2 , which subsequently feedback-modifies any process parameter in the torrefaction step, in the pyrolysis step or in the intermediate step between torrefaction and pyrolysis.

The above-described method, apparatus, use, computer program [product], and computer-readable medium or data signal carrier can be used in the energy recovery of biomass and various waste products.

1 hopper
2 control unit
3 torrefaction reactor
4 first addition device being an injection device for the torrefaction reactor 3
5 first analyser
6 second addition device between the torrefaction reactor 3 and the pyrolysis reactor 7
7 pyrolysis reactor
8 third addition device being an injection device for the pyrolysis reactor 7
9 second analyser

Claims

A method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane, comprising the steps of:
introduction of biomass into at least one torrefaction reactor (3);

torrefaction of biomass at a temperature of 50 °C to 400 °C and a pressure of -50 kPa to +100 kPa in a torrefaction reactor (3);

introduction of the torrefied biomass into at least one pyrolysis reactor (7); and

pyrolysis of the torrefied biomass at a temperature of 400 °C to 800 °C and a pressure of -50 kPa to +100 kPa in a pyrolysis reactor (7) to produce a methane-enriched pyrolysis gas with a methane content of 10 to 60 vol. %,
characterized in that during pyrolysis in step d., a catalyst selected from the group consisting of nickel nanoparticles, copper nanoparticles, cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles and rhodamine 6G, or any combination thereof, is added to the biomass.
A method of enrichment of a gas produced by torrefaction and pyrolysis of biomass with methane, comprising the steps of:
introduction of biomass into at least one torrefaction reactor (3);

torrefaction of biomass at a temperature of 50 to 400 °C and a pressure of -50 kPa to +100 kPa in a torrefaction reactor (3);

introduction of the torrefied biomass into at least one pyrolysis reactor (7); and

pyrolysis of the torrefied biomass at a temperature of 400 to 800 °C and a pressure of -50 kPa to +100 kPa in a pyrolysis reactor (7) to produce a methane-enriched pyrolysis gas with a methane content of 10 to 60 vol. %,
characterized in that before pyrolysis in step d., preferably during torrefaction in step b. and/or after torrefaction in step b. outside the torrefaction reactor (3), a catalyst selected from the group consisting of cobalt nanoparticles, platinum nanoparticles, palladium nanoparticles, ruthenium nanoparticles, rhodium nanoparticles, molybdenum nanoparticles, mercury nanoparticles, rhodamine 6G, and a combination of nickel and cobalt nanoparticles, or any combination thereof, is added to the biomass.
The method according to claim 1 or 2, characterized in that the addition of the catalyst to the biomass is carried out both before pyrolysis in step d. according to claim 2 and during pyrolysis in step d. according to claim 1.
The method according to any one of the preceding claims, characterized in that the catalyst is deposited on the surface of a carrier selected from the group consisting of aluminosilicate, aluminium oxide, magnesium oxide, titanium dioxide, cerium dioxide, zirconium dioxide, or any combination thereof.
The method according to claim 4, characterized in that the catalyst comprises a mixture of 12.0 to 13.0 wt. % of nickel nanoparticles and 1.5 to 2.5 wt. % of cobalt nanoparticles relative to the carrier.
The method according to claim 4, characterized in that the catalyst comprises a mixture of 7.0 to 8.0 wt. % of nickel nanoparticles, 7.0 to 8.0 wt. % of cobalt nanoparticles and 0.1 to 0.5 wt. % of ruthenium nanoparticles relative to the carrier.
The method according to claim 4, characterized in that the catalyst comprises a mixture of 10.0 to 11.0 wt. % of molybdenum nanoparticles and 1.0 to 2.0 wt. % of mercury nanoparticles relative to the carrier.
The method according to claim 4, characterized in that the catalyst comprises 0.1 to 1.0 wt. % of platinum nanoparticles relative to the carrier.
The method according to claim 4, characterized in that the catalyst comprises 0.1 to 2.0 wt. % of copper nanoparticles or palladium nanoparticles or rhodium nanoparticles relative to the carrier.
The method according to claim 4, characterized in that the catalyst comprises 0.05 to 0.30 wt. % of rhodamine 6G relative to the carrier.
The method according to any one of claims 4 to 10. characterized in that the amount of catalyst deposited on the carrier is 0.1 to 5 mg per 1 g of biomass.
The method according to any one of the preceding claims, characterized in that the torrefaction of the biomass in step b. of claim 1 or 2 is carried out in at least two torrefaction reactors (3) arranged in series or in parallel to each other.
The method according to any one of the preceding claims, characterized in that the pyrolysis of the torrefied biomass in step d. of claim 1 or 2 is carried out in at least two pyrolysis reactors (7) arranged in series or in parallel to each other.
The method according to any one of the preceding claims, characterised in that the biomass comprises grass, woody plants, hay, straw, bran, husks, leaves and/or agricultural production waste.
The method according to any one of the preceding claims, characterized in that in the pyrolysis gas produced in step d., or also in the torrefaction gas produced in step b., the methane content is analysed by an analyser (5, 9) to generate input data which are evaluated by a control unit (2), wherein the control unit (2) subsequently feedback-modifies the temperature and/or pressure and/or residence time of the biomass and/or the amount of biomass introduced and/or the ratio of the different biomass components in at least one torrefaction reactor (3) and/or in at least one pyrolysis reactor (7) and/or the amount of the added catalyst.
An apparatus for implementing the method according to any one of the preceding claims, characterized in that it comprises
at least one torrefaction reactor (3) having a biomass inlet and torrefied biomass outlet,

at least one pyrolysis reactor (7) having a torrefied biomass inlet, a pyrolysis residue outlet and a methane-enriched pyrolysis gas outlet,

an addition device (4, 6, 8) for adding a catalyst to the biomass, wherein the addition device is arranged in the torrefaction reactor (3) as an injection device (4) and/or in the pyrolysis reactor (7) as an injection device (8) and/or between the torrefaction and pyrolysis reactors (3, 7) outside both reactors,

an analyser (5, 9) for the analysis of the methane content of the torrefaction gas and/or for the analysis of the methane content of the pyrolysis gas to generate input data; and

a control unit (2) adapted to evaluate the input data and to a feedback modification of the conditions in the torrefaction reactor (3), the addition device (4, 6, 8) and/or the pyrolysis reactor (7).
The apparatus according to claim 16, characterized in that it comprises at least two torrefaction reactors (3) arranged in parallel or in series to each other.
The apparatus according to claim 16 or 17, characterized in that it comprises at least two pyrolysis reactors (7) arranged in parallel or in series to each other.
The apparatus according to any one of claims 16 to 18, characterized in that the addition device (6) arranged between the torrefaction and pyrolysis reactors (3, 7) outside both reactors is a spraying device or a mixing device.
Use of the catalyst of any one of claims 5 to 10 for enriching a gas produced by torrefaction and pyrolysis of biomass with methane.
A computer program [product] comprising instructions that cause the apparatus according to any one of claims 16 to 19 to execute the steps of the method according to claim 15.
A computer-readable medium having stored thereon the computer program [product] according to claim 21, or a data signal carrier carrying the computer program [product] according to claim 21.