WO2020093110A1

WO2020093110A1 - Production of products from bio-energy

Info

Publication number: WO2020093110A1
Application number: PCT/AU2019/051238
Authority: WO
Inventors: Ronald David GOLDSCHLAGER
Original assignee: Hermal Bio Energy International Pty Ltd
Priority date: 2018-11-08
Filing date: 2019-11-08
Publication date: 2020-05-14

Abstract

A process for producing a product from a source of bioenergy comprises (a) pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or and other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a solid bio-solid material, such as a bio-char, and a bio-gas, (b) producing bio-liquids and bio- syngas from the bio-gas from pyrolysis step (a); and (c) mixing bio-solid material and bio-liquids and water and forming a paste product.

Description

PRODUCTION OF PRODUCTS FROM BIO-ENERGY

TECHNIC AU FIEUD

The present invention relates to a process for producing a product, such as by way of example a paste product, that is suitable for use as a fuel or chemicals production, from biomass and other sources of bioenergy, including but not limited to wood waste biomass.

BACKGROUND ART

Currently, the forestry industry generates considerable amounts of low- economic value“waste” biomass, such as sawdust, woodchips, wood shavings, and chipper fines.

Typically, 50% to 60% of the input log wood fibre to sawmills becomes waste biomass in the form of sawdust, woodchips, wood shavings and off-cuts.

Typically, 15% to 40% of timber from plantation and native forests becomes waste biomass.

Typically, 3% to 5% of the input log wood fibre to chipping mills becomes waste biomass.

Other than waste biomass which is used for on-site thermal energy generation, none of the energy stored in the above-described waste biomass is utilised beneficially.

The above description is not an admission of the common general knowledge in Australia or elsewhere.

SUMMARY OF THE DISCUOSURE

In general terms, the invention provides a process for producing a product that is suitable for use as a fuel or for chemicals production from a source of bioenergy that comprises pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a bio- solid material, such as a bio-char, and a bio-gas. The bio-solid material and the bio-gas may be used in a range of downstream applications either in the form produced in the pyrolysis step or as feed materials for downstream production of products. The invention may provide a process for producing a product that is suitable for use as a fuel or for chemicals production from a source of bioenergy that comprises the following steps:

(a) pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a bio- solid material, such as a bio-char, and a bio-gas,

(b) producing bio-liquids and bio-syngas from the bio-gas from pyrolysis step (a); and

(c) mixing the bio-solid material and bio-liquids and water and forming a paste product.

The process may include grinding the bio-solid material to a required particle size for the paste product.

The selected temperature for pyrolysis step (a) may be a low temperature of < 500°C, typically 300-500°C, more typically 350-500°C, and more typically 350-450°C.

Pyrolysis step (a) may be carried out under fast pyrolysis (flash pyrolysis) conditions, as described herein.

Pyrolysis step (a) may include pyrolysing the feed material under pyrolysis conditions that are selected to avoid forming light fractions.

Typically, the operating conditions, such as temperature and residence time at temperature, in the pyrolysis step (a) are selected to optimise the production of the solid bio- solid material compared to the production of the bio-gas to maximize production of the paste product.

Bio-gas processing step (b) may include condensing bio-liquids from the bio-gas from pyrolysis step (a).

The bio-liquids may include bio-tar.

The bio-syngas may include hydrocarbons.

The bio-syngas may include 6-7 Mj/kg of bio-syngas.

The process may include a drying step of drying the feed material to a required moisture content for the pyrolysis step. The process may include condensing moisture released in the drying step and using the condensed water to form the paste product and/or for other process requirements.

The invention also includes a paste product produced by the above-described process.

The paste product may include at least 20, typically at least 25 Mj/kg of the paste product.

The paste product may include at least 15, typically at least 18 Mj/kg of the paste product.

The paste product may include a solids concentration of at least 5, typically 5-

10% bio-solid material.

The invention also provides a plant for producing a product from a source of bioenergy that includes a pyrolyser unit for pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a solid bio-char and a bio-gas.

The invention also provides a plant for producing a paste product from a source of bioenergy that includes:

(a) a pyrolyser unit for pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a bio- solid material, such as a bio-char, and a bio-gas,

(b) a condenser unit for producing bio-liquids and bio- syngas from bio-gas from pyrolyser; and

(c) a paste product unit for producing the paste product from the bio- solid

material from the pyrolyser unit, bio-liquids from the condenser unit, and water.

The pyrolyser may be configured to operate under pyrolysis conditions that avoid forming light fractions.

The pyrolyser unit may be configured to operate under fast pyrolysis (flash pyrolysis) conditions, as described herein. The selected temperature for the pyrolyser unit may be a low temperature of < 500°C, typically 300-500°C, more typically 350-500°C, and more typically 350-450°C.

The production plant may include a dryer unit for drying the feed material before the feed material is transferred to the pyrolysis unit.

The production plant may include a transfer unit for transferring moisture released from the dryer unit to the paste product unit.

The production plant may be located in any suitable location.

The production plant may be advantageously located close to a sustainable source of biomass, such as a sawmill, and thereby make it possible to avoid significant transport costs associated with the removal of wood waste biomass from sawmills as well as reduced emissions from transporting wood waste biomass to a production plant at a remote location for the biomass source.

The term“pyrolysis” is understood herein to mean thermal decomposition of organic material in the absence of or with limited supply of an oxidising agent, such as air or oxygen-enriched air. This could range from“mild pyrolysis” leading to drying and partial thermal decomposition, to“full pyrolysis” resulting in oil, gas and char products. The main products of pyrolysis are gases, liquids, and char. Typically, the gases include water vapor, carbon monoxide, carbon dioxide, hydrogen, and

hydrocarbons. Typically, the liquids include water, tars, and oils. Lower processing temperatures and longer vapor residence times favor the production of char - such processing is often referred to as“slow pyrolysis”. Moderate temperatures and short vapor residence times favor the production of liquids - such processing is often referred to as“fast pyrolysis”.

The term“fast pyrolysis” is understood herein to mean pyrolysis with a short residence time, typically less than a minute, more typically less than 45 seconds, more typically less than 30 seconds.

The term“paste” is understood herein to mean a mixture of bio-liquid, bio-char and water.

Typically, in the context of the invention, the term“paste” includes a mixture of bio-liquid, bio-solid material, such as bio-char, and water produced from the pyrolysis process itself. The term“biomass” is understood herein to mean living or recently living organic matter. Specific biomass includes, by way of example, the above-described forestry industry products, agricultural products, biomass produced in aquatic environments such as algae, agricultural residues such as straw and other crop stubble and chaff, olive pits, and agricultural hemp and marijuana plant production waste and nut shells, animal wastes, municipal and industrial residues.

The term“bio-solid” material is understood herein to mean a partially or completely carbonised biomass obtained from sustainable sources. Bio-char is an example of a bio-solid material.

The feed material for the pyrolysis step may be (a) agricultural waste such as crop waste and/or (b) wood waste biomass from any one or more than one of harvesting operations in plantation and native forests, chipping operations, sawmilling operations, and sustainable wood products manufacturing operations.

The invention is based on the use of a closed pyrolysis system, typically a fast pyrolysis closed system, and on forming the paste product from the outputs of the pyrolysis system.

Features of the invention include the following features:

• A self-sustaining thermochemical process for converting biomass to a paste product and other useful products for producing work/power and bio-energy.

• At least a part of condensed moisture from the drying step can be used as make up water for mixing with bio-solid material, such as bio-char + bio-liquids to produce the paste product.

• The potential for production of useful work/power from combustion of the paste product in a combustor or a modified internal combustion engine.

• Mixing condensed bio-liquids produced from bio-gas from the pyrolysis step with bio- solid material, such as bio-char from the pyrolysis step to maximize the heating value of the paste product for subsequent combustion in a combustor or a modified internal combustion engine.

• Further to the previous dot point, hot flue gas from the combustor or a modified internal combustion engine can be used within the dryer - to maximize process efficiency. • Further to the previous dot point, cooled flue gas from the combustor can be used within the dryer to maximize process efficiency.

• A portion of the bio-solid material, such as bio-char, from the pyrolysis step can be combusted to generate heat to keep the pyrolysis step as a self-sustaining step. The remainder of the biosolid material, such as bio-char, from the pyrolysis step can be mixed with bio- liquids, as described above.

• The non-condensable bio-syngas can be converted to bio-energy such as bio chemicals and bio-fuels via a bio-hydrocarbons synthesis unit (such as a Fischer Tropsch process unit).

· The potential to feed-back“waste” oxygen produced in a Fischer Tropsch

process unit to the combustor - thereby reducing the need for added air. The oxygen substitution for added air provides higher/improved efficiencies in the combustion process. In addition, the oxygen substitution for added air avoids nitrogen in air, so that the bio- syngas is nitrogen-free, and this avoids/saves the need/cost of separating nitrogen from the bio-syngas.

• The potential for the process to produce clean CO2 that has significant

commercial uses in a number of industries, including the food and beverage industry. DESCRIPTION OF FIGURES

The invention is described further by way of example only with reference to the accompanying Figures, of which:

Figure 1 is a flow sheet that summarises an embodiment of the process and production plant of the present invention; and

Figure 2 is a drawing that illustrates an embodiment of an overall sustainable commercial system that includes the process and plant of the flow sheet of Figure 1 and biomass production that feeds biomass into the flow sheet and downstream processing options. DESCRIPTION OF EMBODIMENT

An embodiment of the process and production plant of the present invention is described with reference to the flowsheet of Figure 1.

The process shown in the flow sheet of Figure 1 produces a paste product from wood waste or other sources of and other sources of biomass that comprises the following steps:

(a) drying a feed material in the form of a wood waste biomass and/or other biomass in a drying unit 3 to a suitable moisture content for the pyrolysis step in the process;

(b) pyrolysing the dried feed material at a selected temperature, such as but not necessarily at a low temperature of < 500°C, typically 300-500°C, more typically 350-500°C, and more typically 350-450°C, under fast pyrolysis (flash pyrolysis) conditions in a closed system pyrolyser unit 5 that, by virtue of the selected operating conditions, including temperature and residence time, avoids forming light fractions and decomposing the feed material and producing a solid bio-char output 7 (or any other suitable bio solid material output) and a bio-gas output 9,

(c) grinding a part of the bio-char output 7 from the pyrolyser unit in a suitable mill 11;

(d) producing a bio-liquid 13, typically a bio-tar, and a bio- syngas 15 from the bio-gas output 9 from pyrolysis step in a bio-syngas condenser unit 17; and

(e) mixing the ground bio-char 7, bio-liquid 15 and water 19 supplied as

condensed water from the drying unit 3 and as make-up water, in a mixing unit 21 and forming a paste product 23.

Typically, the operating conditions, such as temperature and residence time at temperature, in the pyrolysis step are selected to optimise the production of the solid bio-char compared to the production of the bio-gas to maximize production of the paste product.

Further to item (e) above, the moisture released in the drying unit 3 is transferred to a condenser unit 25 and the liquid water from the condenser unit 25 is transferred to and used as at least part of the water input 19 to the paste product mixing unit 21. A part of the bio-char output 7 from the pyrolyser unit 5 is combusted in a combustion unit 27 and the output heated combustion gases 29 are used to provide heat for the pyrolyzer unit 5 via indirect heat exchange relationship.

The flowsheet also shows examples of possible downstream uses of the paste product from the paste product mixing unit 21 and the bio- syngas 15 produced in the bio-syngas condenser unit 17. These downstream uses include, by way of example:

(a) using the paste product 23 as a source of energy in a combustion unit or a modified internal combustion engine 31 and producing work/power;

(b) using the bio-syngas 15 in a bio-hydrocarbons synthesis unit 33, such as a Fischer Tropsch process unit, and producing bio-hydrocarbons 37 and an oxygen by-product; and

(c) using the bio-hydrocarbons 37 in one or more of bio-chemicals, bio-fuels, and bio-solvent production.

Features of the embodiment shown in the flowsheet of Figure 1 are as follows:

• Water evaporated from the dryer unit 3 is used in the process - see

condensed water stream 19 - for higher efficiency and/or in downstream processes, such as bio-chemicals production.

• Heated gas 35 produced in the combustion unit or a modified internal combustion engine 31 can be used within the process - specifically, in the dryer unit 31 for higher efficiency.

• Cooled flue gas 41 from the pyrolyser unit 5 can be used within the process - specifically, in the dryer unit 3 for higher efficiency.

• The pyrolyser unit 5 is indirectly heated via indirect heat exchange with combustion gas produced in the combustor 27.

• The oxygen by-product 39 from the Fischer Tropsch process unit can be used as an energy source for the combustion unit 27 for the indirectly heated pyrolyser unit 5. As noted above, this use of oxygen is beneficial in reducing the need for added air.

• The“dryer/pyrolysis unit 3/5 combination can easily be controlled to vary moisture content during pyrolysis. This provides unique control of composition of exit gases (i.e.“bio-gas” - the CO and H₂ ratios, etc.).

• Products of the pyrolysis unit 5 include: o Solid (carbon/char).

o Liquid (pyrolysis hydrocarbons) in significant quantities o Gases.

• Initial calculations are that the usable, high grade energy produced is about 1.5 MWt per tonne of wood waste biomass.

• The bio-char may have some“activated carbon” properties, excellent for use in catalysis.

Thermo gravimetric analysis and char preparation

The following characterisation work has been undertaken on about a tonne of wood waste biomass samples in two different forms (dust and chips) from the Hermal Bio Energy Pty Limited:

• Thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) of biomass.

• Based on the TGA and DTG data, a suitable bio-char preparation range has been identified as 300-500°C.

• Bio-char has been prepared at 300, 400 and 500°C using a large muffle furnace for which temperature calibration was completed first.

Pyrolysis for liquid production

• A bench scale laboratory fast pyrolysis reactor has been used successfully to produce a bio-char, bio-gas, and a liquid bio-tar.

Biomass

The elemental composition of wood waste biomass and other types of biomass differs based on where these species are grown.

Compared to other solid fuels such as coal, wood waste biomass has higher volatile and oxygen content, but low heating value and fixed carbon content.

Additionally, the sulphur content in wood waste biomass is small, mostly less than 0.5 wt. %. In addition, typically the inorganics in wood waste biomass are also generally very low.

The main components of wood waste biomass are cellulose, hemicellulose, and lignin, each of which is different in their decomposition behaviour. The decomposition of each element occurs in a different temperature range and depends on heating rate, particle size and presence of the contaminants. Hemicellulose is the easiest one to be pyrolized, next would be cellulose, while lignin is the most difficult one.

Products from biomass pyrolysis

The two primary products obtained from pyrolysis of wood waste biomass and other types of biomass are bio-char and bio-gas, with a part of the bio-gas condensing to a dark brown viscous bio-tar and a bio-syngas.

Bio-char

Thermal degradation of lignin and hemicellulose in wood waste biomass results in a considerable mass loss in the form of volatiles, leaving behind an amorphous carbon matrix which is referred to as biochar. Depending on the biomass and pyrolysis conditions, 10 to 35% biochar is produced. It has been reported in the technical literature that three different temperature regions produce different bio-char yields during pyrolysis, as follows:

• 450-500 °C (Low- temperature zone): bio-char quantity was high due to low devolatilization rates and low carbon conversion.

• 550-650 °C (Moderate- temperature zone): bio-char reduced dramatically. The maximum yield in this region was found to be about 8 to 10% of biochar

• >650 °C (High- temperature zone): bio-char yield was very low

The properties of bio-char depend on pyrolysis as well as feedstock conditions. Generally, the following characteristics can be observed during biochar production:

1. Bio-char physical characteristics are much affected by pyrolysis conditions such as reactor type and shape, biomass type and drying treatment, feedstock particle size, chemical activation, heating rate, residence time, pressure, the flow rate of inert gas, etc.

• Pyrolysis operating conditions such as higher heating rate (up to 105- 500 °C/s), shorter residence time and finer feedstock produce finer bio char whereas slow pyrolysis with larger feedstock particle size results in a coarser bio-char.

• Crop residues and manures generate a finer and more brittle structured bio-char in pyrolysis processes. 2. Bio-char mainly consists of carbon along with hydrogen and various inorganic species in two structures: stacked crystalline graphene sheets and randomly ordered amorphous aromatic structures. The C, H, N, O and S are commonly combined as heteroatoms that influence the physical and chemical properties of biochar. However, composition, distribution and proportion of these molecules in biochar depend on a variety of factors including source materials and the pyrolysis methodology used.

Bio-syngas

Temperature and moisture content affect the bio-syngas production through heat transfer processes.

Bio-syngas mainly comprises hydrogen (H₂) and carbon monoxide (CO). It can also contain methane (CH₄), carbon dioxide (CO2) water vapour (H2O), nitrogen (N2) and a light hydrocarbon such as C2H4, C2H6.

Bio-liquids, such as bio-tar

Bio-liquids, such as bio-tar produced from the condensation of bio-gas from the pyrolyser, have the following advantages:

• Bio-liquids, such as bio-tar, are transportable.

• It has high energy density.

Biomass pyrolysis reactors

The reactor options include, by way of example only:

• Bubbling fluidized bed.

• Circulating fluidized bed.

• Ablative reactor.

• Rotating cone reactor.

• PyRos reactor.

• Auger reactor.

Figure 2 is a drawing that illustrates an embodiment of an overall sustainable commercial system that includes the process and plant of the flow sheet of Figure 1 and biomass production that feeds biomass into the flow sheet and downstream processing options.

With reference to Figure 2, the system includes the following elements: (a) a source of biomass, such as forests, etc. that produces biomass - with the biomass production being renewable and sustainable and acting as a CO2 sink;

(b) using the biomass as a feed input to the process and plant of the flow sheet of Figure 1 and for other uses including building materials and food; and

(c) using the paste product, bioenergy product, bio-hydrocarbon product, and the oxygen by-product from the process and plant of the flow sheet of Figure 1 beneficially within the process/plant and for other end uses.

Many modifications may be made to the embodiment of the invention described above without departing form the spirit and scope of the invention.

Claims

1. A process for producing a product that is suitable for use as a fuel or for chemicals production from a source of bioenergy that comprises pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a bio-solid material, such as a bio char, and a bio-gas.

2. A process for producing a product that is suitable for use as a fuel or for chemicals production from a source of bioenergy that comprises the following steps:

(c) mixing the bio- solid material and bio-liquids and water and forming a paste product.

3. The process defined in claim 1 or claim 2 wherein pyrolysis step (a) is carried out under fast pyrolysis (flash pyrolysis) conditions.

4. The process defined in any one of the preceding claims includes grinding bio solid material produced in pyrolysis step (a) to a required particle size for the paste product.

5. The process defined in any one of the preceding claims wherein the pyrolysis step (a) includes pyrolysing the feed material under pyrolysis conditions that are selected to avoid forming light fractions.

6. The process defined in any one of the preceding claims wherein the selected temperature for pyrolysis step (a) is a low temperature of < 500°C, typically 300-500°C, more typically 350-500°C, and more typically 350-450°C.

7. The process defined in any one of the preceding claims wherein bio-gas processing step (b) includes condensing bio-liquids from the bio-gas from pyrolysis step (a).

8. The process defined in claim 7 wherein the bio-liquids include bio-tar.

9. The process defined in any one of the preceding claims includes a drying step of drying the feed material for pyrolysis step (a) to a required moisture content for the pyrolysis step.

10. The process defined in claim 9 includes condensing moisture released in the drying step and using the condensed water to form the paste product and/or for other process requirements.

11. A plant for producing a product from a source of bioenergy that includes a pyrolyser unit for pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed system and decomposing the feed material and producing a solid bio-char and a bio-gas.

12. A plant for producing a product from a source of bioenergy that includes:

(a) a pyrolyser unit for pyrolysing a feed material in the form of a wood waste biomass and/or other biomass and/or and other sources of bioenergy at a selected temperature under pyrolysis conditions in a closed and

decomposing the feed material and producing a bio-solid material, such as a bio-char, and a bio-gas,

(b) a condenser unit for producing bio-liquids and bio- syngas from bio-gas from pyrolyser; and (c) a paste product unit for producing the paste product from bio-solid material from the pyrolyser unit, bio-liquids from the condenser unit, and water.

13. The plant defined in claim 12 wherein the pyrolysis unit is configured to operate under fast pyrolysis (flash pyrolysis) conditions.

14. The plant defined in claim 12 or claim 13 wherein the selected temperature for the pyrolyser unit is a low temperature of < 500°C, typically 300-500°C, more typically 350-500°C, and more typically 350-450°C.

15. The plant defined in any one of claims 12 to 14 wherein the pyrolyser is configured to operate under pyrolysis conditions that avoid forming light fractions.