Gasifier for households applying continuous volumetric biomass gasification technology

Abstract

The invention relates to the biomass gasification equipment for households that applies biomass gasification technology and burns the generated biomass gas to generate heat for cooking and / or to produce biochar. The equipment according to the invention is a type of continuous volumetric biomass gasification equipment, operating in batches. This equipment is in the form of a vertical cylinder, including a fuel chamber, inside this chamber includes a primary air distribution unit located at its bottom to distribute the primary air, the secondary air box is located inside the space between the two shells of the equipment. In another option, there is also a gasification chamber inside the fuel compartment of the gasification equipment.

Description

GASIFIER FOR HOUSEHOLDS APPLYING CONTINUOUS VOLUMETRIC BIOMASS GASIFICATION TECHNOLOGY

[0001] The invention belongs to the field of energy production from biomass, specifically biomass gasification. The biomass gasification and biomass gas combustion equipment for heat generation according to the invention (called Gasio) is a type of continuous volumetric biomass gasification equipment, operating in batches.

[0002] Biomass gasification aims to efficiently produce combustible gas from carbon-based materials, especially plants such as wood, straw, etc., by heating fuel in a closed and oxygen-deficient volume, at a typical temperature of about 550-6500C (can be up to 12000C) and the amount of oxygen supplied is about 23-30% of the amount of oxygen needed to completely burn the fuel. Under these conditions, biomass fuel participates in a series of reactions:

[0003] (1) C + O2= CO2+ Q (393.5kJ) (exothermic) is a direct combustion reaction

[0004] (2) C + H2O = CO + H2– Q (-185.3kJ) (endothermic)

[0005] (3) CO + H2O = CO2+ H2+Q (7.2kJ) (exothermic) synthesis gas reactions

[0006] (4) C + CO2= 2CO – Q (-192.5kJ) (endothermic)

[0007] (5) C + 2H2= CH4+ Q (74.9kJ) (exothermic)

[0008] It is noted that since carbon is the majority element in the fuel, the direct combustion of carbon (reaction (1) is the main source of heat generation, while the overall effect of the synthesis gas reactions (syngas) (2), (3), (4), (5) is endothermic.

[0009] The result of this chain of reactions is synthesis gas, a combustible mixture of CO (carbon monoxide), H2(hydrogen) and CH4(methane), which is used as a fuel for thermal applications. When burning (oxidizing) these gases:

[0010] CO gives a red flame and burns slowly according to the reaction:

[0011] (6) 2CO + O2= 2CO2+ Q (586kJ) (exothermal)

[0012] H2burns rapidly with a colorless flame:

[0013] (7) 2H2+ O2= 2H2O + Q (483.6kJ) (exothermal)

[0014] CH4burns rapidly with a blue flame:

[0015] (8) CH4+ 2O2= CO2+ 2H2O + Q (891kJ) (exothermic)

[0016] The successive reaction stages in a typical biomass gasifier can be described as follows: Biomass fuel is stacked in a vertical column, air is supplied from below and fire is ignited from above. Once the equipment is stable (2 minutes to 1 hour depending on the type and size of the equipment), the reaction zones begin to form clearly. Biomass fuels participate in the reaction zones in the following order:

[0017] (a) Dehydration: The biomass begins to heat up, reducing the moisture content to 0 (dry fuel) and the temperature reaches 1500C. Water vapor, if it enters the pyrolysis and gasification zones, will participate in the above reactions (2) and (3).

[0018] (b) Torrefaction: Biomass is heated up to 3500C, no change in chemical composition because it has not participated in the reaction. However, physically, the internal friction of the fuel block has decreased sharply, the fuel surface is scorched, does not reabsorb moisture and is ready to participate in reactions in the pyrolysis and gasification zones.

[0019] (c) Pyrolysis: In this area, the average temperature reaches 550 ± 500C. The above chain of chemical reactions begins to take place here. Initially, the most combustible substances in the biomass (volatility) such as essential oils and short-chain hydrocarbons react first, followed by less combustible substances, such as sugars, starches, lignin, some hemicelluloses and cellulose. Due to the lack of oxygen, the fixed carbon that forms the 'skeleton' that shapes the unburned material during this stage - mainly cellulose - still exists in the form of biochar, accounting for about 30-35% of the total mass of fuel input. Thus, the pyrolysis stage converts about 65-70% of the biomass mass into syngas (H2, CO and CH4).

[0020] (d) Gasification: This is the gasification stage to the most difficult-to-burn fuel part, biochar. The temperature of the gasification zone is usually around 600 - 8000C, even up to 12000C. In the gasification zone, reactions (2), (3), (4) and (5) occur completely, converting biochar, CO2and steam into synthesis gas (syngas).

[0021] The final part of the gasification stage is sometimes referred to as 'reduction' because it completely converts the biochar into syngas. The solid part of the fuel after burning is only ash and can reduce the original fuel volume by up to 99%. The highlight of this region is the syngas reactions that do not require oxygen. That is why the complete gasification process usually only occurs in industrial equipment thanks to the ability to maintain the correct oxygen / fuel ratio throughout the reaction, so that oxygen is only supplied enough for the direct combustion zone and does not go to the gasification zone. In the case of excess oxygen, direct combustion reaction (complete combustion of syngas and fixed carbon) will occur in the gasification zone, reducing efficiency and reducing the life of the equipment.

[0022] Currently, biomass equipment types apply the following gasification methods:

[0023] (i) Small batch (intermittent) units, mainly serving household cooking needs or small-scale production, are batch units, of two main types: Top Lit UpDraft (TLUD), and Bottom Lit Down Draft (BLDD).

[0024] (ii) Large-scale industrial gasification systems operate continuously, using wood chips or fuel pellets. The synthesis gas produced is used to generate electricity and heat simultaneously. The gasification scheme applied is bottom combustion, top air supply (BLDD - Bottom Lit Down Draft). In continuous equipments, the reaction zones are fixed, while the fuel moves through the reaction zones in turn, and ash and biochar (if any) are drained away.

[0025] Small batch gasifiers often have low capacity, low gasification efficiency, are difficult to adjust during operation, and have high production costs. As for the equipments (cookstoves) that can cook continuously, they are just improved cookstoves and not real gasifiers.

[0026] The purpose of the invention is to overcome the disadvantages as mentioned above.

[0027] The invention provides a biomass gasification equipment (gasifier or cookstove) that can be used in households for domestic purposes such as cooking and heating. The equipment is improved to provide high and thorough gasification efficiency, clear and blue flame with good combustion properties, reducing toxic gas emissions, e.g., CO, into the environment.

[0028] According to the first embodiment, the invention provides a biomass gasification equipment applying biomass gasification technology (or called household gasifier), the equipment includes the following parts:

[0029] a fuel chamber 1 is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, the outer shell of this chamber is a water jacket 2 which is a sealed chamber containing water inside and surrounding the gasifier, the outer surface of the water jacket 2 has a water inlet at the bottom and a water outlet at the top; between fuel chamber 1 and water jacket 2 is an air space;

[0030] a bottom 4 of the equipment is located at the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc plate with an outer edge folded and embossed to increase stiffness;

[0031] a primary air distribution unit 9 is fixed above one end of the primary air box 5a, wherein the combination of the primary air distribution unit (9) and this primary air box is arranged to lie above the bottom surface of the equipment;

[0032] a primary air box 5a is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit 5 and is also connected to an air divider valve 8 to distribute the air received from the air supply fan located outside the gasification equipment;

[0033] a secondary air box 5b is located in the space between the fuel chamber 1 and the water jacket 2, extending from the air distribution unit 5 to the combustion chamber 7 to supply secondary air to this combustion chamber;

[0034] a combustion chamber 7 is located directly above the fuel chamber 1, which is connected to the fuel chamber through syngas distribution holes created at the bottom of the combustion chamber;

[0035] an air divider valve 8 is connected at one end to the air distribution tube unit 5 and at the other end to the air supply fan;

[0036] a grate is arranged on the surface of the combustion chamber 7;

[0037] a round plate smoke cover is used when the gasifier (cookstove) is turned off.

[0038] According to the first embodiment above, wherein:

[0039] The primary air distribution unit 9 is in the form of a circular cylinder, its upper surface of which is a circular flat plate and the surface of this plate is arranged with evenly spaced ventilation holes, this flat plate is sealed with the upper end of the vertical cylinder 9a to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder 9a;

[0040] The o-ring 9b is arranged inside the said internal space and is coaxial with the vertical cylinder 9a, wherein the o-ring 9b can be rotated relative to the vertical cylinder 9a around a fixed axis by adjusting the lever 9c which welded to the center of the o-ring 9b, wherein on the surface of the o-ring 9b along its circumference there are inverted U-shaped openings;

[0041] The combustion chamber 7 can be easily removed from the gasifier body for fueling and lighting the gasifier; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the air distribution holes from bottom to top and this secondary air ventilation holes are aligned with each other from top to bottom; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of the secondary air into the middle of the combustion chamber.

[0042] According to the first embodiment above, in which the o-ring 9b is rotated by adjusting the lever 9c,

[0043] wherein in the state where the lever 9c is not rotated, the inverted U-shaped openings on the o-ring 9b do not coincide with the ventilation holes on the vertical cylinder 9a, resulting in the primary air not being blown horizontally;

[0044] wherein in the state where the lever 9c is rotated, the o-ring 9b rotates, the inverted U-shaped openings on the o-ring 9b coincide with the ventilation holes on the vertical cylinder 9a, resulting in the primary air being blown horizontally.

[0045] According to the first embodiment above, in which on the circumferential surface of the combustion chamber 7 there is:

[0046] Radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of gas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;

[0047] Eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and gas.

[0048] According to the first embodiment above, in which:

[0049] The air divider valve 8 is in the form of a lever, consisting of 3 parts: an outer tube 8a, an air divider damper 8b and a control lever 8c; in which the air divider damper is attached to the control lever, when the control lever is pushed forward, the air divider damper will rotate upward, causing the air to enter the primary air box, when the control lever is pulled back, the air divider damper will rotate downward, causing the air to enter the secondary air box; or

[0050] The air divider valve 8 has cross shape, including 3 parts: an outer tube 8a', an air divider damper 8b', a control lever 8c', in which the outer tube 8a' is in the shape of a hollow rectangular box and is divided into two separate compartments, the upper compartment is connected to the secondary air supply tube, the lower compartment is connected to the primary air supply tube; the air divider damper 8b' is designed in a cross shape separated by a circular plate in the middle; the control lever 8c' is connected to the air divider damper 8b'; when the control lever 8c' is placed along the outer tube, the air divider damper at the upper plate position blocks all the air passing through the upper compartment of the outer tube and the lower plate at the air divider damper is fully opened to let the air pass through the lower compartment, at which time the primary air flow is fully opened and all the secondary air is closed; when the control lever is in a horizontal position relative to the outer tube, the upper air divider damper is parallel to the outer tube and allows air to pass through the upper chamber, while the lower air divider damper is perpendicular to the outer tube and prevents air from passing through the lower chamber. At that time, the air will pass entirely through the secondary air supply tube and not enter the primary air supply tube.

[0051] According to the second embodiment, the invention provides a biomass gasification equipment applying biomass gasification technology (or called household gasifier), this equipment includes the following parts:

[0052] a fuel chamber 1 is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, the outer shell of this chamber is water jacket 2 which is a sealed chamber containing water inside and surrounding the household gasifier, the outer surface of water jacket 2 has a water inlet at the bottom and a water outlet at the top; between fuel chamber 1 and water jacket 2 is an air space;

[0053] a gasification chamber 10 is placed in the center of the fuel chamber 1 such that the distance between the outer surface of the gasification chamber 10 and the inner surface of the fuel chamber 1 is between 2.5 cm and 3 cm, wherein the gasification chamber 10 is in the form of a hollow cylinder with both ends when not placed in the center of the fuel chamber 1;

[0054] a bottom 4 of the equipment is located at the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc plate with an outer edge folded and embossed to increase stiffness;

[0055] a primary air distribution unit 9 is fixed above one end of the primary air box 5a, in which the combination of the primary air distribution unit (9) and this primary air box is arranged to lie above the bottom surface of the equipment;

[0056] a primary air box 5a is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit 5 and is also connected to the air divider valve 8 to distribute the air received from the air supply fan located outside the gasification cookstove;

[0057] a secondary air box 5b is located in the space between the fuel chamber 1 and the water jacket 2, extending from the air distribution tube unit 5 to the combustion chamber 7 to supply secondary air to this combustion chamber;

[0058] a combustion chamber 7 is located directly above the fuel chamber 1, which is connected to the fuel chamber through syngas distribution holes created at the bottom of the combustion chamber;

[0059] an air divider valve 8 is connected at one end to the air distribution tube unit 5 and at the other end to the air supply fan;

[0060] a grate is arranged on the surface of the combustion chamber 7;

[0061] a round plate smoke cover is used when the cookstove is turned off.

[0062] According to the second embodiment above, wherein:

[0063] The primary air distribution unit 9 is in the form of a circular cylinder, the upper surface is a circular flat plate and the surface of this plate has evenly spaced ventilation holes arranged, this flat plate is sealed with the upper end of the vertical cylinder 9a to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder 9a;

[0064] The o-ring 9b is arranged inside the above-mentioned internal space and is coaxial with the vertical cylinder 9a, wherein the o-ring 9b can be rotated relative to the vertical cylinder 9a around a fixed axis by adjusting the lever 9c welded to the center of the o-ring 9b, wherein on the surface of the o-ring 9b along its circumference there are inverted U-shaped openings;

[0065] The combustion chamber 7 can be easily removed from the cookstove body to serve the fueling and lighting process; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and this secondary air distribution holes are aligned with each other from top to bottom; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of secondary air into the middle of the combustion chamber;

[0066] The gasification chamber 10 is used in case the equipment is operated in cooking mode and simultaneously produces biochar.

[0067] According to the second embodiment above, in which the o-ring 9b is rotated by adjusting the lever 9c,

[0068] wherein in the state where the lever 9c is not rotated, the inverted U-shaped openings on the o-ring 9b do not coincide with the ventilation holes on the vertical cylinder 9a, resulting in the primary air not being blown horizontally;

[0069] wherein in the state where the lever 9c is rotated making he o-ring 9b rotates, the inverted U-shaped openings on the o-ring 9b coincide with the air ventilation holes on the vertical cylinder 9a, resulting in the primary air being blown horizontally.

[0070] According to the second embodiment above, in which on the circumferential surface of the combustion chamber 7 there is:

[0071] A radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of gas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;

[0072] An eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and gas.

[0073] According to the second embodiment above, in which:

[0074] The air divider valve 8 is in the form of a lever, consisting of 3 parts: an outer tube 8a, an air divider damper 8b and a control lever 8c; in which the air divider damper is attached to the control lever, when the control lever is pushed forward, the air divider damper will rotate upward, causing the air to enter the primary air box, when the control lever is pulled back, the air divider damper will rotate downward, causing the air to enter the secondary air box; or

[0075] The air divider valve 8 has cross shape, including 3 parts: an outer tube 8a', an air divider damper 8b', a control lever 8c', in which the outer tube 8a' is in the shape of a hollow rectangular box and is divided into two separate compartments, the upper compartment is connected to the secondary air supply tube, the lower compartment is connected to the primary air supply tube; the air divider damper 8b' is designed in a cross shape separated by a circular plate in the middle; the control lever 8c' is connected to the air divider damper 8b'; when the control lever 8c' is placed along the outer tube, the air divider damper at the upper plate position blocks all the air passing through the upper compartment of the outer tube and the lower plate at the air divider damper is fully opened to let the air pass through the lower chamber, at which time the primary air is fully opened and all the secondary air is closed; when the control lever is in a horizontal position relative to the outer tube, the upper air divider damper is parallel to the outer tube and allows air to pass through the upper chamber, while the lower air divider damper is perpendicular to the outer tube and prevents air from passing through the lower chamber. At that time, the air will pass entirely through the secondary air supply tube and not enter the primary air supply tube.

[0076] In another embodiment, the invention relates to a method for producing biochar comprising the step of using gasifier for households using biomass gasification technology according to any of the above embodiments. Preferably, the method for producing biochar comprises the step of using gasifier for household using biomass gasification according to the second embodiment as mentioned above.

[0077] The gasifier has low emission and high efficiency thanks to good quality syngas and complete combustion thanks to thorough mixing of the secondary gas – syngas mixture in the combustion chamber.

[0078] The gasifier using VCBG gasification technology has achieved tier 5 ranking in all indicators, except for PM2.5 fine dust emission parameter which has achieved tier 4. In addition, the thermal efficiency of the cookstove when in use is 83.7%, much higher than the minimum requirement of 50% for tier 5 in the cookstove performance assessment section. Meanwhile, the PM 2.5 fine dust emission index of 15.8 mg / MJ is also much lower than the minimum requirement of 62.0 mg / MJ for tier 4 and almost reaches tier 5, lower than or equal to 5 mg / MJ. The parameters of durability and safety for users also reach the highest level of tier 5.Brief description of the drawings

[0079] . Perspective drawing of biomass gasifier

[0080] : The drawing depicting cross section showing the structure of the biomass gasifier according to the first embodiment

[0081] : The drawing depicting cross section showing the structure of the biomass gasifier according to the second embodiment

[0082] : The drawing depicting cross section in another direction showing the structure of the biomass gasifier according to the second embodiment

[0083] : The drawing depicting combustion chamber

[0084] : The drawing depicting air divider valve (lever type)

[0085] : The drawing depicting air divider valve (cross type)

[0086] : The drawing depicting air distribution tube unit

[0087] : The drawing depicting primary air distribution unit

[0088] : The drawing depicting the primary air circulation state when the o-ring in the air distribution is not rotated (biochar production mode)

[0089] : The drawing depicting the primary air circulation state when the o-ring in the air distribution is rotated (thorough gasification mode)

[0090] : The drawing depicting reaction zones in cooking mode (thorough gasification)

[0091] : The drawing depicting reaction zones in cooking and biochar production mode (in the description it may be referred to as biochar production mode)

[0092] Figure 14: The drawing depicting biochar produced after gasification in cooking mode and biochar production

[0093] Gasifier for households applying biomass gasification technology basically has the structure shown in Figures 1, 2, 3 and 4. This equipment has a vertical cylindrical body, its outermost layer is a water jacket. There is a fuel chamber inside which is also the reaction chamber / gasification chamber. The fuel chamber is a hollow cylinder with the same centerline as the body of the equipment. In another embodiment, when the equipment is operating in biochar production mode, there is also a gasification chamber inside the fuel chamber. This gasification chamber is placed coaxially into the center of the fuel chamber so that the distance between the outer surface of the gasification chamber and the inner surface of the fuel chamber is between 2.5 cm and 3 cm, in which this gasification chamber is in the form of a hollow cylinder with both ends when not placed in the center of the fuel chamber. In any other embodiment, above the fuel chamber is the combustion chamber, where the secondary air and syngas generated from the fuel chamber are mixed and then the mixed gas is burned. The combustion chamber can be separated from the body of the equipment and the fuel chamber when biomass fuel is put into the fuel chamber. Below the fuel chamber is the primary air distribution 9. The primary air distribution unit 9 is hermetically sealed to the primary air box 5a.

[0094] The first embodiment of the invention is shown in, whereby the invention provides a gasifier for households applying biomass gasification, the gasifier includes the following parts:

[0095] The fuel chamber 1 is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, there is a water jacket 2 as outermost layer which is a sealed chamber containing water inside and surrounding the household gasifier, the outer surface of water jacket 2 has a water inlet at the bottom and a water outlet at the top; between fuel chamber 1 and water jacket 2 is an air space;

[0096] The bottom 4 of the equipment is located at the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc plate with an outer edge folded and embossed to increase stiffness;

[0097] The primary air distribution unit 9 is fixed above one end of the primary air box 5a, in which the combination of the primary air distribution unit 9 and this primary air box is arranged to lie above the bottom surface of the equipment;

[0098] The primary air box 5a is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit and is also connected to the air divider valve 8 to distribute the air received from the air supply fan located outside the gasification equipment;

[0099] The secondary air box 5b is located in the space between the two casings of the equipment, extending from the air distribution unit 5 to the combustion chamber 7 to supply secondary air to this combustion chamber;

[0100] The combustion chamber 7 is in the shape of a truncated cone, located directly above the fuel chamber 1, this chamber is connected to the fuel chamber through gas distribution holes (syngas) created at the bottom of the combustion chamber;

[0101] The air divider valve 8 is connected at one end to the air distribution tube unit 5 and at the other end to the air supply fan;

[0102] The grate is arranged on the surface of the combustion chamber 7;

[0103] The round plate smoke cover is used when the cookstove is turned off;

[0104] in which:

[0105] The primary air distribution unit 9 is in the form of a circular cylinder, the upper surface of which is a circular flat plate and the surface of which is arranged with evenly spaced ventilation holes, this flat plate is welded to the upper end of the vertical cylinder 9a to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder 9a;

[0106] The o-ring 9b is arranged inside the said internal space and is coaxial with the vertical cylinder 9a, wherein the o-ring 9b can be rotated relative to the vertical cylinder 9a around a fixed axis by adjusting the lever 9c welded to the center of the o-ring 9b, wherein on the surface of the o-ring 9b along its circumference there are inverted U-shaped openings;

[0107] The combustion chamber 7 can be easily removed from the cookstove body for fueling and lighting the cookstove; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from below and this secondary air supply holes are aligned with each other from above; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of the secondary air into the middle of the combustion chamber.

[0108] The second embodiment of the invention is as shown in Figures 3 and / or 4. Accordingly, the invention refers to a household gasifier applying biomass gasification technology, this equipment includes the following parts:

[0109] The fuel chamber 1 is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, outside this chamber is water jacket 2 which is a sealed chamber containing water inside and surrounding the household gasifier, the outer surface of water jacket 2 has a water inlet at the bottom and a water outlet at the top; between fuel chamber 1 and water jacket 2 is an air space;

[0110] The gasification chamber 10 is placed in the center of the fuel chamber 1 such that the distance between the outer surface of the gasification chamber 10 and the inner surface of the fuel chamber 1 is between 2.5 cm and 3 cm, wherein the gasification chamber 10 is in the form of a hollow cylinder with both ends when not placed in the center of the fuel chamber 1;

[0111] The bottom 4 of the equipment is located at the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc with an outer edge folded and embossed to increase stiffness;

[0112] The primary air distribution unit 9 is fixed above one end of the primary air box 5a, in which the combination of the primary air distribution unit 9 and this primary air box is arranged to lie above the bottom surface of the equipment;

[0113] The primary air box 5a is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit 5 and is also connected to the air divider valve 8 to distribute the air received from the air supply fan located outside the gasification equipment;

[0114] The secondary air box 5b is located in the space between the two casings of the equipment, extending from the air distribution tube unit 5 to the combustion chamber 7 to supply secondary air to this combustion chamber;

[0115] The combustion chamber 7 is located directly above the fuel chamber 1, which is connected to the fuel chamber through syngas distribution holes created at the bottom of the combustion chamber;

[0116] The air divider valve 8 is connected at one end to the air distribution tube unit 5 and at the other end to the air supply fan;

[0117] The grate is arranged on the surface of the combustion chamber 7;

[0118] The round plate smoke cover is used when the cookstove is turned off;

[0119] in which:

[0120] The primary air distribution unit 9 is in the form of a circular cylinder, the upper surface is a circular flat plate and the surface of this plate has evenly spaced ventilation holes arranged, this flat plate is sealed with the upper end of the vertical cylinder 9a to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder 9a;

[0121] The o-ring 9b is arranged inside the above-mentioned internal space and is coaxial with the vertical cylinder 9a, wherein the o-ring 9b can be rotated relative to the vertical cylinder 9a around a fixed axis by adjusting the lever 9c welded to the center of the o-ring 9b, wherein on the surface of the o-ring 9b along its circumference there are inverted U-shaped openings;

[0122] The combustion chamber 7 can be easily removed from the cookstove body to serve the fueling and lighting process; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and this secondary air supply holes are aligned with each other from top to bottom; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of secondary air into the middle of the combustion chamber;

[0123] The gasification chamber 10 is used in this case when the cookstove is operated in cooking mode and simultaneously produces biochar.

[0124] According to the first or second embodiment above, in the equipment according to the invention, the o-ring 9b is rotated by adjusting the lever 9c, specifically as follows:

[0125] When in the state of the lever 9c not rotating, the o-ring 9b is not rotating, the inverted U-shaped openings on the o-ring 9b do not coincide with the ventilation holes on the vertical cylinder 9a, resulting in the primary air not being blown horizontally ();

[0126] When the lever 9c is rotated, the o-ring 9b rotates, the inverted U-shaped openings on the o-ring 9b coincide with the ventilation holes on the vertical cylinder 9a, resulting in the primary air being blown horizontally ().

[0127] According to the first or second embodiment above, in the equipment of the invention, as shown in, the combustion chamber 7 is in the shape of a truncated cone, on the circumferential surface of the combustion chamber 7, there is:

[0128] Radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of gas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;

[0129] Eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and gas.

[0130] According to the first or second embodiment above, in the equipment according to the invention, the air divider valve 8 may include a lever type air divider valve as shown inand a cross type air divider valve as shown in, specifically as follows:

[0131] In, the air divider valve 8 is in the form of a lever, consisting of 3 parts: an outer tube 8a, an air divider damper 8b and a control lever 8c; in which the air divider damper is attached to the control lever, when the control lever is pushed forward, the air divider damper will rotate upward, causing the air to enter the primary air box, when the control lever is pulled back, the air divider damper will rotate downward, causing the air to enter the secondary air box; or

[0132] In, the air divider valve 8 is cross-shaped, including 3 parts: an outer tube 8a', an air divider damper 8b', a control lever 8c', in which the outer tube 8a' is in the shape of a hollow rectangular box and is divided into two separate compartments, the upper compartment is connected to the secondary air supply tube, the lower compartment is connected to the primary air supply tube; the air divider damper 8b' is designed in a cross shape separated by a circular plate in the middle; the control lever 8c' is connected to the air divider damper 8b'; when the control lever 8c' is placed along the outer tube, the air divider damper at the upper plate position blocks all the air passing through the upper compartment of the outer tube and the lower plate at the air divider damper is fully opened to let the air pass through the lower compartment, at which time the primary air chamber is fully opened and all the secondary air is closed; when the control lever is in a horizontal position relative to the outer tube, the upper air divider damper is parallel to the outer tube and allows air to pass through the upper chamber, while the lower air divider damper is perpendicular to the outer tube and prevents air from passing through the lower chamber. At that time, the air will pass entirely through the secondary air supply tube and not enter the primary air supply tube.

[0133] According to the first or second embodiment above, in the equipment of the invention, the combustion chamber 7 is located immediately above the fuel chamber 1, which is connected to the fuel chamber through syngas distribution holes created at the bottom of the combustion chamber;

[0134] More specifically, according to the first or second embodiment as mentioned above, the combustion chamber 7 is in the form of a truncated cone made of heat-resistant material, fixed to the unit including the grate and the top cover of the fuel chamber, in which this combustion chamber can be easily removed from the cookstove body to serve the fueling and lighting process. The small end of the combustion chamber is directed downwards and sealed to the sealing disc 7a. On the circumferential surface of the combustion chamber, there are radial secondary air supply holes arranged in rows to distribute secondary air into the combustion chamber, the lower row of holes has a larger diameter and the upper row of holes has a smaller diameter. The design of secondary ventilation holes must ensure vertical alignment with the syngas distribution holes going from bottom to top. In addition, on the surface of the perimeter of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of the secondary air to the middle of the combustion chamber. In addition, the combustion chamber is supported by a 7a ring-shaped sealing disc with a smooth surface in contact with the combustion chamber support ring. The sealing disc 7a is located above the combustion chamber support ring, preventing gas from passing through the contact surface between the sealing disc 7a and the combustion chamber support ring.

[0135] According to the first or second embodiment above, in the equipment according to the invention, on the circumferential surface of the combustion chamber 7 there is:

[0136] The secondary air supply holes are radial to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of gas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;

[0137] The eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and gas. This helps to improve gas combustion efficiency as well as improve the power and performance of the equipment.

[0138] In any embodiment as mentioned above, the gasifier according to the invention includes: an air divider valve 8 having one end coupled to an air distribution tube unit 5 to supply air to the primary air boxes and secondary air boxes, and the other end connected to an air supply fan. The air supply fan is installed outside gasifier; the trivet is arranged on the surface of the combustion chamber 7; and the round plate-shaped smoke-proof cover is used when the cookstove is turned off.

[0139] Description of operating principle of the equipment according to the invention.

[0140] During operation, air is blown by the air supply fan through the air divider valve 8 to distribute air into the primary air box 5a and the secondary air box 5b. In this case, the air divider valve 8 has a lever design to adjust the amount of air entering the primary air box and the secondary air box. When starting the cookstove, push the control lever 8c towards the cookstove, the air divider damper 8b will be pushed up to widen the air path into the primary air supply tube 5a and the air will not be able to enter the secondary air box 5b. Conversely, when pulling the control lever 8c towards the fan, the air divider damper 8b will lower, the primary air path will be smaller and the air path into the secondary air supply tube will increase. In other words, if the air divider 8 is used in a cross-shaped form, when the control lever 8c' is placed along the outer sleeve, the air divider damper at the upper plate position blocks all air passing through the upper chamber of the outer sleeve and the lower plate at the air divider damper is fully opened to let air pass through the lower chamber, then the primary air is fully opened and all secondary air is closed; when the control lever is in a horizontal position relative to the outer sleeve, the upper air divider damper is parallel to the outer sleeve and lets air pass through the upper chamber, while the lower air divider damper is perpendicular to the outer sleeve and prevents air from passing through the lower chamber, then the air will pass entirely through the secondary air supply tube and not enter the primary air supply tube.

[0141] Air goes from primary air box 5a to primary air distribution unit 9. If the cookstove is in the starting process, move the lever 9c so that the o-ring 9b covers the horizontal air vents on the side of the vertical cylinder 9a so that the primary air enters the fuel chamber only vertically (). When it is necessary to blow and cut the coal leg in the feed chamber. Move the lever 9c so that the grooves on the o-ring 9b coincide with the ventilation holes on the vertical tube 9a of the primary air distribution unit 9. At this time the primary air will blow both horizontally and vertically ().

[0142] Air from primary air distribution 9 enters fuel chamber 1, at high speed, oxygen ignites directly with biomass fuel in reaction 1, producingCO2gas and releasing heat. This direct combustion zone is only concentrated on the surface of the primary air box and the center of the gasifier because this area is supplied with oxygen. The surrounding areas do not experience direct fire due to lack of oxygen in those areas. The heat released in the direct combustion zone will partly be pushed up by thermal convection and inertia of the hot air flow from the primary air box surface into the biomass material mass. Part of the heat is transferred to the surrounding area of direct combustion by thermal radiation, leading to the creation of a gasification zone surrounding the direct combustion area. Similarly, the pyrolysis zone is formed around the gasification zone creating the structure of the zones as shown in.

[0143] Accordingly, during operation, three-dimensional zones are formed that surround each other: direct combustion zone, gasification zone and pyrolysis zone. At the innermost is the direct combustion zone, where reaction (1) takes place, burning carbon to produce heat and CO2. Surrounding the direct combustion zone is the gasification zone, where reactions (2), (3), (4), (5) to create gas take place strongly thanks to the absorption of heat energy and CO2 from the direct combustion zone. The outermost part is the pyrolysis zone, where volatiles and combustibles participate in the reaction chain (2), (3), (4), (5) to enrich and increase the amount of H2 and CH4 in the syngas, while absorbing most of the heat energy that the gasification zone has not used. The generated syngas will go up to the burner.

[0144] In combustion chamber 7, gas goes from bottom to top and then through the holes on gas distribution plate 7b to enter the combustion chamber. Here the gas meets secondary air from the holes in the combustion chamber body and ignites. The holes on the gas distribution plate are evenly spaced to distribute gas evenly in the combustion chamber. In the middle of the gas distribution plate there are 3 large holes to concentrate the gas in the middle of the combustion chamber 7. When other areas are shut off these vents act as re-lights for the remaining vents. In the middle of the combustion chamber there is a 7f fire distribution plate. When gas and secondary air go from below to hit the 7f fire distribution plate, the flame will be evenly distributed to the space around the combustion chamber, helping the flame burn more evenly. At the same time, increasing the time for the gas and secondary gas to meet helps the combustion process (reactions (6), (7), (8)) to take place more thoroughly. Makes the exhaust gas after combustion cleaner (reduces the content of unburned CO in the exhaust gas after combustion).

[0145] The central air supply tube 7i supplies secondary air to the 3 gas holes on the gas distribution plate 7b. The central air supply tube 7i is placed at an angle of 30 degrees off-center relative to the radial line. Such design has the effect of creating a swirling air flow in the combustion chamber, helping to increase the distance that the syngas travels in the combustion chamber, leading to a longer residence time of the gas in the combustion chamber (reactions (6), (7), (8) take place more thoroughly). Reduces CO content in exhaust gas.

[0146] The water in water jacket 2 moves along the water supply line, which is water at ambient temperature, supplied from below. Water is heated by utilizing the heat released from the household gasifier, hot water is released through the water outlet above. The design has a water jacket to take advantage of excess heat escaping from the equipment shell and improve the efficiency of the cookstove.Biochar production mode

[0147] According to the second embodiment of the invention as shown in the foregoing sections, wherein the gasification chamber 10 is placed centrally in the fuel chamber 1 and coaxial with the fuel chamber. Then place fuels into the space created by the inner wall of fuel chamber 1 and the outer wall of gasification chamber 10. Air from the primary air distribution 9 enters the gasification chamber 10 vertically at high speed, oxygen ignites directly with biomass fuel according to reaction (1) to produceCO2gas and release heat. This direct combustion zone is only concentrated on the upper surface of the primary air box and the center of the gasification chamber because this area is supplied with oxygen. The surrounding areas do not experience direct fire due to lack of oxygen in those areas. The heat released in the direct combustion zone will partly be pushed up by thermal convection and inertia of the hot air flow from the primary air box surface into the biomass material mass. Outside the gasification chamber 10, i.e. the fuel layer contained in the space created by the inner wall of the fuel chamber 1 and the outer wall of the gasification chamber 10 receives heat from the thermal radiation emitted from the gasification chamber shell 10, forming a pyrolysis zone. In this space, due to the lack of oxygen, the fixed carbon that forms the 'skeleton' that shapes the unburned material in this stage - mainly cellulose - still exists in the form of biochar. The reaction zones in biochar production mode are depicted in.

[0148] After the above operation, biochar is obtained in the space outside the gasification chamber 10, that is, the space created by the inner wall of the material chamber 1 and the outer wall of the gasification chamber 10 and the biochar in the gasification chamber 10. The biochar storage areas after equipment operation are shown in Figure 14.

[0149] Detail description of actual operation of the gasifier

[0150] Lightingstep: Lift combustion chamber 7 out of the equipment. Load fuels for the cookstove (pellets, chopped firewood, branches, small firewood, etc.) until it is about 2-3cm from the top of the fuel compartment. Put combustible fuels such as wood shavings, corn husks, straw, dry leaves on the surface of the given fuel layer. Connect the fan to the air distribution 8. Push the air distribution control lever all the way toward the cookstove. Then turn on the fan and light the fire to burn the flammable fuel layer above. When the fire has caught fire after 1 – 2 minutes. Return combustion chamber 7 to its original position. After 1-2 minutes the grouping process will end and the equipment will switch to normal VCBG operation.

[0151] Normal operation phase

[0152] The direct combustion zone is formed and expanded from the upper surfaces and the area around the primary air distribution 9, expanding deep inside the material mass thanks to the high primary air velocity blowing from the primary air box, then to the gasification zone, the pyrolysis zone in the form of spherical zones surrounding each other. The drying zone and the dehumidification zone are also formed in turn. The size of these zones depends on the amount of primary air input and how the primary air is controlled, horizontally and vertically: when high power is needed, adjust the air distribution to increase the primary air flow, the reaction zones expand and the drying zone is pushed up; conversely, when it is necessary to reduce the power of the equipment, reduce the primary air flow, the reaction zones narrow towards the center of the reaction chamber. The drying zone is lowered and wraps around the pyrolysis zone. When biochar production is required, close the horizontal primary air path through the 9c lever. When it is necessary to burn all the biochar, open the horizontal air holes on the primary air distribution 9.

[0153] In steady state, the highest temperature in the core of the fuel block reaches about 1200 ± 1000C and gradually decreases towards the periphery (adjacent to the reaction chamber shell) - to about 3500C. Above the pyrolysis zone are the drying and dehumidification zones, with the temperature decreasing from bottom to top, from inside to outside. The temperature of the outer edge of the dehumidification zone is close to the outside ambient temperature.

[0154] As the gas rises out of the material surface, it moves towards the combustion chamber. Prevents gas from going back up to the feed inlet or leaking through the ash discharge outlet. Gas approaches the flame vent. Here, the gas is mixed with air in the secondary air and ignited. Due to the narrowing design at the gas burner, the fast moving secondary gas is drawn in and mixed with the syngas. The main reason why small gasifiers cannot operate continuously is because they cannot create negative pressure in the feeding area.

[0155] The combustible gas mixture enters the combustion zone of the combustion chamber and ignites. Thanks to the careful mixing due to the adjustment in some designs of secondary ventilation holes on the surface along the perimeter of the combustion chamber, the mixture burns completely without soot or tar. Note that the combustion area at the burner has been formed from the start-up phase and continues to the steady state phase.

[0156] Water in water jacket 2 moves along the cold water inlet line supplied from below. Hot water is discharged from the water outlet at the top. To utilize excess heat released from the equipment's shell and improve the efficiency of the cookstove.In biochar production mode:

[0157] The gasification chamber 10 is centrally located and coaxial with the fuel chamber 1. Then pour fuel into fuel chamber 1 and gasification chamber 10. Air from the primary air distribution 9 enters the gasification chamber 10 vertically at high speed, oxygen ignites directly with biomass fuel according to reaction (1) to produceCO2gas and release heat. This direct combustion zone is only concentrated on the upper surface of the primary air box and the center of the gasification chamber because this area is supplied with oxygen. The surrounding areas do not experience direct fire due to lack of oxygen in those areas. The heat released in the direct combustion zone will partly be pushed up by thermal convection and inertia of the hot air flow from the primary air box surface into the biomass material mass. Outside the gasification chamber 10, the fuel layer receives heat from the thermal radiation emitted from the gasification chamber shell 10, forming a pyrolysis zone. Because it does not receive oxygen, the fixed carbon that forms the 'skeleton' that shapes the unburned material in this stage - mainly cellulose - still exists in the form of biochar. Gasification chamber 10 acts to prevent the outer biochar layer from falling into the gasification zones and burning directly in the central area. After operation, biochar is obtained in the space outside the gasification chamber 10, that is, the space created by the inner wall of the material chamber 1 and the outer wall of the gasification chamber 10 and the biochar in the gasification chamber 10. The biochar storage areas after equipment operation are shown in Figure 14.

[0158] Evaluation of the efficiency of gasifier for householdsTest results of the invention gasifier

[0159] The household gasifier was tested at the Centre for Research in Energy and Energy Conservation , a unit recognized by the Clean Cooking Alliance, according to the standard: ISO 19867-1:2018, March 11-20, 2024.

[0160] - Number of tests: 15

[0161] - Number of test cookstoves: 2

[0162] - Fuel used: eucalyptus woodEvaluation parametersTest resultsComparison with ISO 19867-2018 standardThermal efficiency (%)Tier 5: 83.7%Tier 5: ≥ 50%PM2.5 fine dust emission (mg / MJ)Tier 4: 15.8 mg / MJTier 4: ≤ 62.0 mg / MJTier 5: ≤ 5 mg / MJCO emissions (g / MJ)Tier 5: 2.33 g / MJTier 5: ≤ 3.0 mg / MJSafetyTier 5: 98.5Tier 5: ≥ 95 pointsDurabilityTier 5: 2Tier 5: < 10 points

[0163] Test results of gasifier for households Poor <== ==> GoodTier 0Tier 1Tier 2Tier 3Tier 4Tier 5Thermal efficiency (%)<10≥ 10≥ 20≥ 30≥ 40≥ 50Carbon monoxide emissions (g / MJ)> 18,3≤ 18,3≤ 11,5≤ 7,2≤ 4,4≤ 3,0PM2.5 fine dust emission (mg / MJ)> 1031≤ 1031≤ 481≤ 218≤ 62≤ 5Safety (points)< 60≥ 60≥ 68≥ 77≥ 86≥ 95Durability (points)> 35< 35< 25< 20< 15<10

[0164] Evaluation table of gasifier for households according to ISO 19867-1:2018 standards

[0165] From the above results, the household gasifier using VCBG gasification technology has achieved tier 5 ranking in all indicators, except for PM2.5 fine dust emission parameter which has achieved tier 4. In addition, the thermal efficiency of the cookstove when in use is 83.7%, much higher than the minimum requirement of 50% for tier 5 in the cookstove performance assessment section. Meanwhile, the PM 2.5 fine dust emission index of 15.8 mg / MJ is also much lower than the minimum requirement of 62.0 mg / MJ for tier 4 and almost reaches tier 5, lower than or equal to 5 mg / MJ. The parameters of durability and safety for users also reach the highest level of tier 5.

[0166] The equipment according to the invention can be easily produced on the an industrial scale at low cost. The equipment has the compact structure but high capacity due to superior capacity / volume ratio compared to traditional gasification.

[0167] 1: fuel chamber

[0168] 2: water jacket

[0169] 3: supporting rim

[0170] 4: bottom

[0171] 5: air distribution tube unit

[0172] 5a: primary air box

[0173] 5b: secondary air box

[0174] 6: round plate smoke cover

[0175] 7: combustion chamber

[0176] 7a: sealing disc

[0177] 7b: gas distribution plate

[0178] 7c: perimeter of combustion chamber

[0179] 7d: cookstove surface

[0180] 7e: bolt

[0181] 7f: fire distribution plate

[0182] 7g: nut

[0183] 7h: Grate

[0184] 7i: central air supply tube

[0185] 8: air divider valve

[0186] 8a, 8a’: outer tube

[0187] 8b, 8b’: air divider damper

[0188] 8c, 8c’: control lever

[0189] 9: primary air distribution unit

[0190] 9a: vertical cylinder

[0191] 9b: o-ring

[0192] 9c: lever

[0193] 10: gasification chamber

[0194] Primary air

[0195] Secondary air

Claims

A biomass gasification equipment for households, the equipment includes the following parts:a fuel chamber (1) is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, the outer shell of this chamber is a water jacket (2) which is a sealed chamber containing water inside and surrounding the equipment, the outer surface of the water jacket (2) has a water inlet at the bottom and a water outlet at the top; between the fuel chamber (1) and the water jacket (2) is an air space;a bottom (4) of the equipment is the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc plate with an outer edge folded and embossed to increase stiffness;a primary air distribution unit (9) is fixed above one end of the primary air box (5a), wherein the combination of the primary air distribution unit and the primary air box is arranged to lie above the bottom surface of the equipment;a primary air box (5a) is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit (5) and is also connected to an air divider valve (8) to distribute the air received from the air supply fan located outside the gasification equipment;a secondary air box (5b) is located in the space between the fuel chamber (1) and the water jacket (2), extending from the air distribution unit (5) to the combustion chamber (7) to supply secondary air to this combustion chamber;a combustion chamber (7) is located directly above the fuel chamber (1), which is connected to the fuel chamber through the syngas distribution holes created at the bottom of the combustion chamber;an air divider valve (8) is connected at one end to the air distribution tube unit (5) and at the other end to the air supply fan;a grate is arranged on the surface of the combustion chamber (7);a round plate smoke cover used when the gasification equipment is turned off;characterised in that:the primary air distribution unit (9) is cylindrical in shape, its upper surface is a flat circular plate and the surface of this plate has evenly spaced ventilation holes arranged, this flat plate is sealed with the upper end of the vertical cylinder (9a) to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder (9a);the o-ring (9b) is arranged inside the above-mentioned internal space and is coaxial with the vertical cylinder (9a), wherein the o-ring (9b) can be rotated relative to the vertical cylinder (9a) around a fixed axis by adjusting the lever (9c) welded to the center of the ring (9b), wherein on the surface of the o-ring (9b) along its circumference there are inverted U-shaped openings,the combustion chamber (7) can be easily removed from the gasification equipment body for fueling and lighting the gasification equipment; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and this radial secondary air supply holes are aligned with each other from top to bottom; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of the secondary air into the middle of the combustion chamber.The biomass gasification equipment according to claim 1, wherein the o-ring (9b) is rotatable by adjusting the lever (9c),wherein in the state where the lever (9c) is not rotated, the inverted U-shaped openings on the o-ring (9b) do not coincide with the ventilation holes on the vertical cylinder (9a), resulting in the primary air not being blown horizontally;wherein in the state where the lever (9c) is rotated, the o-ring (9b) rotates, the inverted U-shaped openings on the o-ring (9b) coincide with the ventilation holes on the vertical cylinder (9a), resulting in the primary air being blown horizontally.The biomass gasification equipment according to any of the above claims, in which on the circumferential surface of the combustion chamber (7) there is:radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of syngas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and syngas.The biomass gasification equipment according to any of the above claims, in which the air divider valve (8) is in the form of a lever, including 3 parts: an outer tube (8a), an air divider damper (8b) and a control lever (8c); wherein the air divider damper is attached to the control lever, when the control lever is pushed forward, the air divider damper will rotate upward, causing the air to enter the primary air box, and when the control lever is pulled back, the air divider damper will rotate downward, causing the air to enter the secondary air box.The biomass gasification equipment according to any of claims 1 to 3, wherein the air divider valve (8) is cross-shaped, comprising 3 parts: an outer tube (8a'), an air divider damper (8b'), a control lever (8c'), in which the outer tube (8a') is in the shape of a hollow rectangular box and is divided into two separate compartments, the upper compartment is connected to the secondary air supply tube, the lower compartment is connected to the primary air supply tube; the air divider damper (8b') is designed in the shape of a cross separated by a circular plate in the middle; the control lever (8c') is linked to the air divider damper (8b').A biomass gasification equipment for households, the equipment includes the following parts:a fuel chamber (1) is a hollow cylinder to contain biomass fuel and gasify the biomass fuel contained therein, the outer shell of this chamber is a water jacket (2) which is a sealed chamber containing water inside and surrounding the gasification equipment, the outer surface of the water jacket (2) has a water inlet at the bottom and a water outlet at the top; between the fuel chamber (1) and the water jacket (2) is an air space;a gasification chamber (10) is placed in the center of the fuel chamber (1) so that the distance between the outer surface of the gasification chamber (10) and the inner surface of the fuel chamber (1) is between 2.5 cm and 3 cm, wherein the gasification chamber (10) is in the form of a hollow cylinder with both ends when not placed in the center of the fuel chamber (1);a bottom (4) of the equipment is the bottom of the fuel chamber, made of heat-resistant steel, this bottom is in the form of a circular disc plate with an outer edge folded and embossed to increase stiffness;a primary air distribution unit (9) is fixed above one end of the primary air box (5a), wherein the combination of the primary air distribution unit and the primary air box is arranged to lie above the bottom surface of the equipment;a primary air box (5a) is arranged above and close to the bottom plate, in which the primary air box inlet is close to the secondary air inlet, creating an air distribution tube unit (5) and is also connected to the air divider valve (8) to distribute the air received from the air supply fan located outside the gasification equipment;a secondary air box (5b) is located in the space between the fuel chamber (1) and the water jacket (2), extending from the air distribution unit (5) to the combustion chamber (7) to supply secondary air to this combustion chamber;a combustion chamber (7) is located directly above the fuel chamber (1), which is connected to the fuel chamber through the syngas distribution holes created at the bottom of the combustion chamber;an air divider valve (8) is connected at one end to the air distribution tube unit (5) and at the other end to the air supply fan;a grate is arranged on the surface of the combustion chamber (7);a round plate smoke cover used when the gasification equipment is turned off;characterised in that:the primary air distribution unit (9) is cylindrical in shape, its upper surface is a flat circular plate and the surface of this plate has evenly spaced ventilation holes arranged, this flat plate is sealed with the upper end of the vertical cylinder (9a) to create an internal space, the ventilation holes are created on the surface along the circumference of this vertical cylinder (9a);the o-ring (9b) is arranged inside the above-mentioned internal space and is coaxial with the vertical cylinder (9a), wherein the o-ring (9b) can be rotated relative to the vertical cylinder (9a) around a fixed axis by adjusting the lever (9c) welded to the center of the o-ring (9b), wherein on the surface of the o-ring (9b) along its circumference there are inverted U-shaped openings,the combustion chamber (7) can be easily removed from the gasification equipment body for fueling and lighting the gasification equipment; on the circumferential surface of the combustion chamber, there are radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and this radial secondary air supply holes are aligned with each other from top to bottom; in addition, on the circumferential surface of the combustion chamber, there are also eccentric secondary air supply tubes to supply a part of the secondary air into the middle of the combustion chamber,the gasification chamber (10) is used in cases where the gasification equipment is operated in cooking mode and simultaneously produces biochar.The biomass gasification equipment according to claim 6, wherein the o-ring (9b) is rotatable by adjusting the lever (9c),wherein in the state where the lever (9c) is not rotated, the inverted U-shaped openings on the o-ring (9b) do not coincide with the ventilation holes on the vertical cylinder (9a), resulting in the primary air not being blown horizontally;wherein in the state where the lever (9c) is rotated, the o-ring (9b) rotates, the inverted U-shaped openings on the o-ring (9b) coincide with the ventilation holes on the vertical cylinder (9a), resulting in the primary air being blown horizontally.The biomass gasification equipment according to any of claims 6 to 7, wherein on the circumferential surface of the combustion chamber (7) there is:radial secondary air supply holes to distribute secondary air into the combustion chamber, in which the syngas distribution holes from bottom to top and the secondary air ventilation holes are aligned with each other from top to bottom, helping to increase the contact surface of gas and secondary air, leading to the combustion process taking place right below the combustion chamber and more thoroughly, reducing CO emissions;eccentric secondary air supply tubes supply a portion of secondary air to the center of the combustion chamber, creating a swirling air flow to increase the contact time between secondary air and gas.The biomass gasification equipment according to any of the claims from 6 to 8, wherein the air divider valve (8) is in the form of a lever, including 3 parts: an outer tube (8a), an air divider damper (8b) and a control lever (8c); wherein the air divider damper is attached to the control lever, when the control lever is pushed forward, the air divider damper rotates upward, causing air to enter the primary air box, and when the control lever is pulled back, the air divider damper rotates downward, causing air to enter the secondary air box.The biomass gasification equipment according to any of claims 6 to 8, wherein the air divider valve (8) is cross-shaped, comprising 3 parts: an outer tube (8a'), an air divider damper (8b'), a control lever (8c'), in which the outer tube (8a') is in the shape of a hollow rectangular box and is divided into two separate compartments, the upper compartment is connected to the secondary air supply tube, the lower compartment is connected to the primary air supply tube; the air divider damper (8b') is designed in the shape of a cross separated by a circular plate in the middle; the control lever (8c') is linked to the air divider damper (8b').

Images