FI127670B

FI127670B - A gasifier and a method for adjusting an operation of a gasifier

Info

Publication number: FI127670B
Application number: FI20165593A
Authority: FI
Inventors: Marko Perttilä; Jussi Ojalainen
Original assignee: Raute Oyj
Priority date: 2016-07-18
Filing date: 2016-07-18
Publication date: 2018-11-30
Also published as: FI20165593A

Abstract

The invention relates to a gasifier (100). The gasifier (100) comprises a cylindrical housing part (102) having a center axis (116), a first end (103A), and a second end (103B); a throat section (104) formed on inner surface of the housing part (102) between the first end (103A) and the second end (103B), wherein the throat section (104) comprising at least a truncated substantially cone-shaped sub-section (104A) reducing towards the second end (103B) of the housing part (102), wherein a plurality of nozzles (302) is arranged on the sub-section (104A); and a center nozzle part (106) comprising a substantially cone-shaped section (106A) having a surface facing towards the subsection (104A) and comprising a plurality of nozzles (304). The center nozzle part (106) is configured to be movable along the direction of the center axis (116) of the housing part (102) in order to adjust a functional cross sectional area of at least one plane of the throat section (104). The invention also relates to a method for adjusting an operation of a gasifier (100).

Description

A gasifier and a method for adjusting an operation of a gasifier

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TECHNICAL FIELD

The invention concerns in general the technical field of gasifiers. Especially the 5 invention concerns enhancing the operation of the gasifier.

BACKGROUND

A gasifier is used in a gasification process that converts solid fuel into product gas. Typically, in gasifiers fuel, such as wood based fuel, supplied into a housing part of the gasifier descends by the force of the gravity from an upper part 10 of the gasifier onto a grate. First the moisture of the fuel is evaporated within a drying zone. Next a pyrolysis zone, where dry distillation of the fuel takes place, is formed. Below the pyrolysis zone locates an oxidation zone into which gasification gas is supplied. A layer of carbon and ash forming above the grate forms a reduction zone below the oxidation zone. The formed product gases 15 are conducted through the grate into a discharge pipe.

Various factors affect the optimal operation of a gasifier, including the supply of gasification gas to the oxidation zone, the through-flow of the formed product gases, the supply of fuel, ash removal from the grate, the prevention of the entry of not completely burnt fuel through the grate, for example, when using dif20 ferent fuel particle sizes, the prevention/minimization of the clogging of the grate and the fixing of a possible clogging situation.

Typically one drawback in a gasifier is that it is very sensitive to the changes in the process conditions. Even a small change in the process conditions changes the process so that the quality of the product gas will decline abruptly. The 25 change in the output of the product gas or in the properties of the fuel, such as moisture or particle size, may typically cause temperature drop or rise that may further cause disruption of the gasification reactions. Thus, the tar concentration may increase rapidly, which decreases the possibilities to utilize the product gas.

According to one prior art solution described in the patent publication FI123665 the gasification gas is supplied by means of center nozzles and peripheral nozzles in order to achieve an oxidation zone that has even and wide ring

20165593 prh 16-10-2018 shaped cross sectional area. One of the drawbacks of this prior art solution is the above mentioned sensitivity to the changes in the process conditions. For example if woodchips, which may be used as fuel, are too dry (moisture content is less than 15 percent) the temperature rises too high causing that the 5 process conditions are not optimal. On the other hand if the woodchips have too high moisture content (moisture content is more than 20 percent) or if the particle size of the woodchips decreases, the temperature drops enabling that tar may be formed. Furthermore, the gasification by means of only a single nozzle layer may cause that the oxidation zone is so short in vertical direction 10 that the process does not have enough time to adapt to the changes in the process conditions. Because of the fixed location of the nozzles the operation of the gasifier is optimum only for small range of output of the product gas. If the output of the product gas is reduced, the quality of the gasification gas will gradually deteriorate. The process conditions may be designed for certain 15 moisture content and certain particle size of the woodchips. However, the gasification process may not be adjusted properly, if the properties of the fuel or the output of the product gas changes.

According to another prior art solution described in the patent publication FI122109 the gasification gas is supplied by means of at least one center noz20 zle formed by a discharge end of an oxidation pipe. The center nozzle may be arranged to be moved in the vertical direction in relation to a throat. The throat is formed by a thin disk arranged on the inner surface of the housing part of the gasifier. By lifting the center nozzle up the excessive rise of the temperature at the oxidation zone may be at least partly prevented. However, one 25 drawback caused by the lifting of the nozzle is that the temperature closest to the nozzle is too high and at the same time the temperature outermost from the nozzle is too low. The cross sectional area of the throat may be changed. However, it does not help to keep the process conditions constant, because the gasification gas is supplied from the center nozzle above the thin disk30 shaped throat towards the woodchips and the temperature at the peripheral area will drop significantly. This prior art solution is suitable only for a small range of the output of the product gas. One drawback of this prior art solution is that the distance between the center nozzle and the inner surface of the housing part remains constant, when the center nozzle is moved in the vertical 35 direction. Thus, the temperature at the peripheral area of the gasifier will decrease too much, if the output of the product gas is small.

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One prior art solution described in the patent publication FI113781 discloses a gasifier, wherein the functional cross sectional area of the throat may be changed by means of a conical element arranged in the center of the housing part. The conical element is lifted and lowered in vertical direction through the 5 throat. However, in this prior art solution the nozzles are arranged above the throat on the periphery of the housing part. The change in the functional cross sectional area of the throat affects only the velocity of the gasification gas within the area of the throat, not to the process values at the oxidation zone or at any other zones inside the gasifier.

Some prior art solutions disclose gasifiers comprising a plurality of nozzle layers in vertical direction of the housing part of the gasifier. The plurality of nozzle layers cause that the oxidation zone is longer in vertical direction. Thus, the process is less sensitive to the changes in the properties of the fuel. One drawback of the prior art solution is that the distance that the gasification gas 15 penetrates to the fuel remains constant, because the nozzles are fixedly arranged on the periphery of the housing part. Thus, the temperature in the center of the gasifier is too low, when the output of the product gas is small.

A patent publication US2013097928 A1 discloses a gasification device for the creation of a flammable gas from a solid. The gasification device comprises air 20 entry nozzles arranged to a housing of the gasification device in two levels and air pipes arranged to an air supply pipe extending centrally in the longitudinal direction of the gasifier to supply air to a gasification zone. The gasification device further comprises an oxidation zone configured as an oxidation chamber arranged centrally inside the gasification device, being surrounded by the gasi25 fication zone.

Thus, there is a need to further develop the gasifier solutions.

SUMMARY

An objective of the invention is to present a gasifier and a method for adjusting an operation of a gasifier. Another objective of the invention is that the gasifier 30 and the method for adjusting an operation of a gasifier improve the adjustability of a gasifier solution.

The objectives of the invention are reached by a gasifier and a method as defined by the respective independent claims.

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According to a first aspect, a gasifier is provided, wherein the gasifier comprising: a cylindrical housing part having a center axis in longitudinal direction of the housing part, a first end, and a second end, wherein a fuel is supplied inside the housing part from the first end; a throat section formed on inner sur5 face of the housing part between the first end and the second end, wherein the throat section comprising at least a truncated substantially cone-shaped subsection reducing towards the second end of the housing part, wherein a plurality of nozzles for supplying gasification gas is arranged on the sub-section; and a center nozzle part comprising a substantially cone-shaped section having a 10 surface facing towards the sub-section and comprising a plurality of nozzles for supplying gasification gas, wherein the center nozzle part is configured to be movable along the direction of the center axis of the housing part in order to adjust a functional cross sectional area of at least one plane of the throat section.

A ring shaped oxidation zone may be formed by the gasification gas supplied from the plurality of nozzles.

Alternatively or in addition, the plurality of nozzles may be arranged to form a plurality of nozzle layers in at least one of the following: the center nozzle part, the sub-section of the throat section, wherein each of the plurality of nozzle 20 layers comprising at least two nozzles.

The plurality of nozzle layers may be arranged to supply gasification gas independently from each other.

Alternatively or in addition, at least one of the plurality of nozzle layers may be arranged to supply different gasification gas than the other of the plurality of 25 the nozzle layers.

Alternatively or in addition, at least one of the plurality of nozzle layers may be arranged to supply gasification gas having different properties or different temperature and/or pressure and/or velocity.

The length of the oxidation zone in the direction of the center axis of the hous30 ing part may be arranged to be adjusted by supplying gasification gas from one nozzle layer or from a plurality of nozzle layers.

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The size of the plurality of nozzles may be arranged to be adjusted continuously. Alternatively or in addition, the shape of the plurality of nozzles may be arranged to be adjusted continuously.

The gasification gas may be any gas comprising oxygen.

The gasifier may further comprise a grate arranged between the throat section and the second end of the housing part, wherein the grate may be arranged to be continuously adjusted in the direction of the center axis of the housing part.

The gasifier may further comprise fuel supplying means for supplying fuel inside the housing part.

Moreover, the center nozzle part may be arranged offset from the center axis of the housing part and the center nozzle part may be configured to be rotated eccentrically around the center axis of the housing part.

According to a second aspect, a method for adjusting an operation of a gasifier as defined above is provided, wherein the method comprising: moving the cen15 ter nozzle along the direction of the center axis of the housing part in order to adjust a functional cross sectional area of at least one plane of the throat section.

The method may further comprise supplying gasification gas from a plurality of nozzle layers independently from each other, wherein a plurality of nozzles is 20 forming the plurality of nozzle layers in at least one of the following: the center nozzle part, the sub-section of the throat section, wherein each of the plurality of nozzle layers comprising at least two nozzles.

The exemplary embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the ap25 pended claims. The verb to comprise is used in this patent application as an open limitation that does not exclude the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated.

The novel features which are considered as characteristic of the invention are 30 set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objectives and advantages thereof, will be best understood from the following

20165593 prh 16-10-2018 description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF FIGURES

The embodiments of the invention are illustrated by way of example, and not 5 by way of limitation, in the figures of the accompanying drawings.

Figure 1 illustrates schematically a cross sectional view of a gasifier according to an embodiment of the invention.

Figure 2 illustrates schematically an example of reaction zones inside a gasifier according to the invention.

Figure 3A illustrates schematically a closer view of the gasifier according to an embodiment of the invention.

Figure 3B illustrates schematically a closer view of the gasifier according to another embodiment of the invention.

Figure 3C illustrates schematically a closer view of the gasifier according to 15 another embodiment of the invention.

Figure 4 illustrates schematically an example of at least one inlet for providing gasification gas to a plurality of nozzle layers of a throat section.

Figure 5A illustrates schematically an example of a functional cross sectional area of a throat section according to an embodiment of the invention.

Figure 5B illustrates schematically another example of a functional cross sectional area of a throat section according to an embodiment of the invention.

Figure 6 illustrates schematically a closer view of the gasifier according to an embodiment of the invention.

DESCRIPTION OF SOME EMBODIMENTS

Figure 1 illustrates a cross sectional view of a gasifier 100 according to an embodiment of the invention. The gasifier comprises a cylindrical housing part 102, a throat section 104, and a center nozzle part 106. In addition, the gasifier

20165593 prh 16-10-2018 may also comprise a grate 108, fuel supplying means 110, and a discharge outlet 112.

The cylindrical housing part 102 has a center axis 116 in longitudinal direction of the housing part 102, a first end 103A, and a second end 103B. The center 5 axis 116 is an imaginary axis, not an actual part of the housing part 102. A fuel may be supplied inside the housing part 102 from the first end 103A by means of the fuel supplying means 110. The fuel may be wood based fuel, such as woodchips. Alternatively or in addition, the fuel may be any solid organic material, such as agricultural waste, biomass, and plastic waste. The fuel descends 10 by the force of the gravity from the first end 103A of the housing part 102 towards the second end 103B of the housing part 102.

A throat section 104 is formed on inner surface of the housing part 102 between the first end 103A and the second end 103B of the housing part 102.

The throat section 104 comprising at least a truncated substantially cone15 shaped sub-section 104A reducing towards the second end of the housing part. On the sub-section 104A of the throat part 104 a plurality of nozzles for supplying gasification gas is arranged. The gasification gas may be any gas comprising oxygen. For sake of clarity the plurality of nozzles of the throat part 104 is not shown in Figure 1. The gasification gas may be supplied to the plu20 rality of nozzles of the throat section 104 through at least one inlet 114. The velocity of the product gas, which may comprise hydrocarbons, carbon dioxide, water, for example in addition to the gasification gas, inside the gasifier 100 increases at the throat section 104 at least momentarily, because of a decreased cross sectional area of the gasifier 100 at the throat section 104.

The center nozzle part 106 comprises a substantially cone-shaped section 106A. The substantially cone-shaped section 106A is opening towards the first end 103A of the housing part 102. Round shapes enable smooth supply and flow of gasification gas and at least partly prevent formation of cold zones inside the housing part 102. Furthermore, the shape of the center nozzle part 30 106 is determined so that it supports at least partly a bed of the fuel, but it does not cause bridging of the fuel. The substantially cone-shaped section 106A has a surface facing towards the sub-section of the throat section 104. The facing surfaces of the substantially cone-shaped section 106A and the sub-section of the throat section 104 may be parallel as in Figure 1, but the 35 facing surfaces do not have to be parallel. The substantially cone-shaped sec

20165593 prh 16-10-2018 tion 106A comprises a plurality of nozzles for supplying gasification gas. For sake of clarity the plurality of nozzles of the center nozzle part 106 is not shown in Figure 1. At least the substantially cone-shaped 106A section of the center nozzle part 106 is symmetrical and the substantially cone-shaped sec5 tion 106A of the center nozzle part 106 may be concentric with the housing part 102 in the direction of the center axis 116 of the housing part 102. Furthermore, the gasification gas may be supplied to the plurality of nozzles of the center nozzle part 106 through at least one inlet 115 arranged in conjunction with the center nozzle part 106.

The center nozzle part 106 is configured to be movable along the direction of the center axis 116 of the housing part 102 in order to adjust a functional cross sectional area of at least one plane of the throat section 104. The functional cross sectional area of at least one plane of the throat section 104 may be defined as a ring-shaped area between the center nozzle part 106 and the inner surface of the housing part 102 forming the throat section 104, when the center nozzle part 106 reaches to the at least one plane of the throat section 104. Alternatively, the functional cross sectional area of at least one plane of the throat section 104 may be defined as a circular area, when the center nozzle part 106 does not reach to the at least one plane of the throat section 104. The functional cross sectional area of the at least one plane of the throat section

104 may be symmetrical and concentric with the housing part 102 in the direction of the center axis 116 of the housing part 102. The functional cross sectional area of at least one plane of the throat section 104 may be adjusted, when the center nozzle part 106 is moved so that it intersects with the cross 25 sectional area of the throat section 104 at said at least one plane of the throat section 104. The throat section 104 described above may be considered to be formed by a plurality of planes having different cross sectional areas. The plurality of planes of the throat section 104 may be symmetrical and concentric with the housing part 102 in the direction of the center axis 116 of the housing 30 part 102. The multiple planes are imaginary planes, not actual parts of the gasifier 100.

Alternatively or in addition, the throat section 104 may be considered to form a three-dimensional volume and the center nozzle part 106 is configured to be movable along the direction of the center axis 116 of the housing part 102 in 35 order to adjust a functional volume of the throat section 104. The functional volume of the throat section 104 may be defined as a volume between the

20165593 prh 16-10-2018 center nozzle part 106 and the inner surface of the housing part 102 forming the throat section 104.

By reducing the functional cross sectional area of at least one plane of the throat section 104 the dwell time of the gas in the throat section 104 may be 5 adjusted in order to affect progress of the gasification reactions and the temperature in the throat section 104 and after the throat section 104. Additionally, the velocity of the product gas inside the throat section 104 may be increased by reducing the functional cross sectional area of at least one plane of the throat section 104. In addition to the adjusting the functional cross sectional 10 area of at least one plane of the throat section 104, the distance between the plurality of nozzles of the center nozzle part 106 and the plurality of nozzles of the throat section 104 may be adjusted by moving the center nozzle part 106 along the direction of the center axis 116 of the housing 102. The center nozzle part 106 may be configured to move continuously in order to continuously 15 adjust the functional cross sectional area of at least one plane of the throat section 104 and the distance between the plurality of nozzles of the center nozzle part 106 and the plurality of nozzles of the throat section 104. Consequently, the adjustability of the gasifier 100 and thus also the operation of the gasifier 100 may be at least partly improved. The adjustability of the gasifier 20 100 enables a fast adaptation to the changes in the process conditions. Thus, the gasifier 100 may provide continuously substantially uniform and high quality product gas regardless of the desired output of the product gas.

The center nozzle part 106 may also comprise cylindrical shaft section 106B.

The center nozzle part 106 may be arranged to be connected to the first end 25 103A of the housing part 102 moveably with fastening means 107 so that the center nozzle part 106 may be moved at least in the direction of the center axis 116 of the housing part 102. Alternatively, the center nozzle part 106 may be arranged to be connected to the second end 103B of the housing part 102.

The fastening means 107 may also comprise means for moving the center 30 nozzle part 106, such as actuating motor, cylinder, or crank. The center nozzle part 106 may further comprise an intermediate section 106C between the substantially cone-shaped section 106A and the shaft section 106B. The intermediate section 106C may have a truncated substantially cone-shaped shape as shown in Figure 1. Alternatively, the intermediate section 106C may also have 35 another shape.

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The grate 108 may be arranged between the throat section 104 and the second end 103B of the housing part 102. The grate 108 may be arranged to be adjusted in the direction of the center axis 116 of the housing part 102. The adjustment of the grate 108 may be continuous. By adjusting the grate 108 in the direction of the center axis 116 of the housing part 102 the temperature of the layer of carbon 210 may be adjusted to be higher than 600 °C in order to optimize the degradation of hydrocarbons into beneficial hydrocarbons, such as benzene or toluene.

In a co-current fixed bed type gasifier, also called as down draft gasifier, the 10 formed product gases are conducted through the grate into a discharge outlet

112 arranged on the periphery of the housing part 102 between the grate 108 and the second end 103B of the housing part 102 as shown in Figure 1. The discharge outlet 112 may be a pipe for example.

In the gasification process inside the gasifier 100 several reactions occur. Fig15 ure 2 illustrates a rough example of zones where the different reactions occur inside the gasifier 100 according to the invention. Figure 2 is only a nonlimiting exemplary illustration of the locations of the reaction zones inside the gasifier 100 in the direction of the center axis 116 of the housing part 102. Drying reaction occurs within a drying zone 202. Drying is the reaction that occurs 20 closest to the first end 103A of the housing part 102. In the drying reaction the moisture of the fuel is at least partly evaporated. The drying reactions may occur between 95 °C and 200 °C. Preferably, the drying reactions may occur between 105 °C and 125 °C. Next in the gasification process a pyrolysis reaction occurs within a pyrolysis zone 204, where a dry distillation of the fuel takes 25 place. In the pyrolysis reaction volatile matter is released and a char is produced. The pyrolysis may occur between 150 °C and 900°C. The pyrolysis products flow towards the second end 103B of the housing part 102 to the next zone, which is an oxidation zone 206 into which gasification gas may be supplied. Alternatively or in addition, gasification gas may also be supplied into the 30 pyrolysis zone 204 in small amounts. The oxidation zone 206 may also be called as a heat zone. The oxidation reaction occurring within the oxidation zone 206 provides heat for the subsequent reactions occurring within the following zone, which is a reduction zone 208. The oxidation reactions may occur between 900 °C and 1300 °C. The main chemical formula of the oxidation re35 action is C + O2 —► CO2. The oxidation reaction products move into the reduction zone 208. The reduction reactions require heat. Thus, the temperature de11

20165593 prh 16-10-2018 creases gradually during the reduction reactions. The reduction reactions may occur above 700 °C. The main formulas of reduction reactions are C + H2O -> CO + H2, C + CO2 —>· 2CO, and C+2H2 -> Chk. The oxidation reactions and reduction reactions may be called as gasification reactions. The product gas5 es, such as carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), water vapor (H2O), methane (Chk), may be led out from the gasifier 100 through the discharge outlet 112. A layer of carbon dust and ash 210 is formed on the grate 108 within a reduction zone 208.

Figure 3A illustrates a closer view of the gasifier 100 according to an embodi10 ment of the invention showing the throat section 104 and the center nozzle part 106. In Figure 3A the plurality of nozzles 304 on the substantially coneshaped section 106A of the center nozzle part 106 and the plurality of nozzles 302 on the truncated substantially cone-shaped sub-section 104A of the throat section 104 are shown. The plurality of nozzles 302, 304 may be arranged to 15 form a plurality of nozzle layers comprising at least two nozzles. The plurality of nozzle layers is arranged on top of each other in the direction of the center axis 116 of the housing part 102. The plurality of nozzles 304 may be arranged to form a plurality of nozzle layers on the substantially cone-shaped section 106A of the center nozzle part 106. Alternatively or in addition, the plurality of 20 nozzles 302 may be arranged to form a plurality of nozzle layers on the truncated substantially cone-shaped sub-section 104A of the throat section 104. In Figure 3A both the center nozzle part 106 and the throat section 104 comprise three nozzle layers. However, they may comprise more or less nozzle layers.

The number of the nozzle layers in the center nozzle part 106 may be different 25 than the number of the nozzle layers in the throat section 104. The center nozzle part 106 may comprise preferably three or four nozzle layers. Alternatively or in addition, the throat section 104 may comprise preferably three or four nozzle layers.

Preferably, the nozzles 302 on the truncated substantially cone-shaped sub30 section 104A of the throat section 104 may be arranged to supply gasification gas in the direction substantially perpendicular to the truncated substantially cone-shaped sub-section 104A of the throat section 104. Alternatively or in addition, the plurality of nozzles 304 on the substantially cone-shaped section 106A of the center nozzle part 106 may be preferably arranged to supply gasi35 fication gas in the direction substantially perpendicular to the surface of the substantially cone-shaped section 106A of the center nozzle part 106. In other

20165593 prh 16-10-2018 words, the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 may be arranged to supply gas substantially towards each other. However, the invention is not limited to that the surface of the substantially cone-shaped section 106A of the center nozzle 5 part 106 and the truncated substantially cone-shaped sub-section 104A of the throat section 104 are parallel with each other.

The throat section 104 may also comprise a second truncated substantially cone-shaped sub-section 104B reducing towards the first end 103A of the housing part 102. In addition, on the second sub-section 104B of the throat 10 part 104 a plurality of nozzles for supplying gasification gas may be arranged in order to ensure that the temperature within the whole oxidation zone 206 may be kept sufficient high for the oxidation and reduction reactions.

The plurality of nozzle layers may be arranged to supply gasification gas independently from each other. For example, the gasification gas may be supplied 15 from one nozzle layer of the center nozzle part 106 and from two nozzle layers of the throat section 104. Alternatively or in addition, at least one of the plurality of nozzle layers may be arranged to supply different gasification gas than the other of the plurality of the nozzle layers. Alternatively or in addition, water spray or steam, for example, may be supplied together with the gasification 20 gas from at least one of the plurality of nozzle layers in order to adjust the gasification reactions, if the moisture content of the fuel is very dry, for example. Alternatively or in addition, at least one of the plurality of nozzle layers may be arranged to supply gasification gas having different properties than the gasification gas supplied from the other of the plurality of the nozzle layers. For ex25 ample, each of the plurality of nozzle layers may be arranged to supply gasification gas having different properties. The properties of the gasification gas may be oxygen content, moisture, for example. Alternatively or in addition, temperature and/or pressure and/or velocity of the gasification gas may be different in each of the plurality of nozzle layers, for example. The properties or 30 temperature and/or pressure and/or velocity of the gasification gas may be arranged to be adjusted continuously. Thus, also the intensity of the gasification gas supply from each of the plurality of nozzle layers may be adjusted independently.

Because of the plurality of nozzles 302 of the throat section 104 and the plural35 ity of nozzles 304 of the center nozzle part 106 a long ring shaped oxidation

20165593 prh 16-10-2018 zone 206 may be formed. If only one nozzle layer is used, the oxidation zone

206 would be thinner in the direction of the center axis 116 of the housing part

102. When the oxidation zone is longer, the process is less sensitive to the changes in the properties of the fuel. The ring-shaped oxidation zone 206 is concentric with the housing part 102 in the direction of the center axis 116 of the housing part 102 and has an adjustable cross sectional area and length. Alternatively or in addition, the length of the oxidation zone 206 in the direction of the center axis 116 of the housing part 102 may be arranged to be adjusted by arranging the gasification gas to be supplied from one nozzle layer of from 10 a plurality of nozzle layers. Alternatively or in addition, the length of the oxidation zone 206 in the direction of the center axis 116 of the housing part 102 may be arranged to be adjusted by increasing the velocity of the product gas in the throat section 104 by reducing the functional cross sectional area of at least one plane of the throat section 104. The length of the oxidation zone 206 15 may be adjusted continuously. The adjustment of the length of the oxidation zone 206 in the direction of the center axis 116 of the housing part 102 enables that process conditions of the gasification process may be adjusted according to the need of output of the product gas and properties of the fuel. For example, if the distance between the nozzles and the grate 108 is between 20 400 to 500 millimeters and the temperature may decrease even from 1300 °C at the reduction zone 208 to 600 °C at the grate 108 as described above. The temperature drop may be already about 300 °C within the first 100-200 millimeters, if the gasifier has only one nozzle layer. If the gasifier has plurality of nozzle layers the temperature may be kept above 1000 °C even up to 400 millime25 ters.

Furthermore, the size of the plurality of nozzles 302, 304 may be arranged to be adjusted continuously. In addition, the size of the plurality of nozzles 302, 304 may be arranged to be adjusted independently from each other. Alternatively or in addition, the size of the at least two nozzles of each of the plurality 30 of nozzle layers may be arranged to be adjusted independently from the size of the at least two nozzles of the other of the plurality of nozzle layers. Alternatively or in addition, the shape of the plurality of nozzles 302, 304 may be arranged to be adjusted continuously. In addition, the shape of the plurality of nozzles 302, 304 may be arranged to be adjusted independently from each 35 other. Alternatively or in addition, the shape of the at least two nozzles of each of the plurality of nozzle layers may be arranged to be adjusted independently

20165593 prh 16-10-2018 from the shape of the at least two nozzles of the other of the plurality of nozzle layers. The size and/or the shape of the nozzles may be adjusted in order to at least partly prevent that the temperature does not drop in the center between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104, i.e. farthest from the plurality of nozzles 302, 304, within the oxidation zone 206 below a lower temperature limit. The lower temperature limit in the oxidation zone may be 900 °C for example.

In Figure 3A the gasifier 100 is configured to operate at the maximum output of the product gas, wherein the center nozzle part 106 is in a first position and all 10 of the plurality of nozzle layers is configured to be in operation. In the first position the center nozzle part 106 is in its extreme position closest to the first end 103A of the housing part 102. When the center nozzle part 106 is in the first position, the functional cross sectional area of at least one plane of the throat section 104 is at its maximum. The distance D between the plurality of nozzles 15 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 may be between 400 millimeters and 700 millimeters. When the center nozzle part 106 is in the first position the distance D may be 695 millimeters, for example.

If the process conditions, such as the output of the product gas or the proper20 ties of the fuel, change, the gasifier 100 may be adjusted in order to keep the temperature within the oxidation zone 206 substantially constant and to provide substantially uniform and high quality product gas. Figure 3B illustrates a closer view of the gasifier 100 according to an embodiment of the invention, wherein the gasifier 100 is adjusted. The center nozzle part 106 is in a second 25 position and only some of the plurality of nozzle layers is configured to be in operation. In the second position the center nozzle part 106 is in a position between the extreme positions of the center nozzle part 106. By arranging the center nozzle part 106 closer to the second end 103B of the housing part 102 the functional cross sectional area of at least one plane of the throat section 30 104 is decreased. Furthermore, the distance D between the plurality of nozzles

304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 is arranged to be decreased. When the center nozzle part 106 is in the second position the distance D may be 465 millimeters, for example.

If the particle size of the fuel is decreased, the gasification gas does not pene35 trate as deep into the fuel as it would penetrate into the fuel having larger par

20165593 prh 16-10-2018 tide size. By decreasing the distance D between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 also the distance that the gasification gas is required to penetrate in the fuel decreases in order to at least partly prevent forming a cold zone between 5 the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104. If the moisture content of the fuel is too dry, for example less than 15 percent, the temperature within the oxidation zone 206 rises too high, for example over 1300 °C. In order to keep the temperature substantially constant, the amount of the gasification gas may be de10 creased. Decreasing the amount of gasification gas, in turn, requires that the distance D between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 is decreased in order to least partly prevent forming a cold zone inside the oxidation zone 206. In the cold zone harmful tar may be formed. Alternatively or in addition, a gasification 15 gas having different temperature may be supplied from different nozzle layers as described above in order to keep the temperature substantially constant at least within the oxidation zone 206. Preferably, the temperature may also be kept constant within the other zones of the gasifier 100 by supplying gasification gas having different temperatures from different nozzle layers. For exam20 pie, gasification gas having high temperature, such as between 400 °C and

500 °C, may be supplied from the nozzle layer closest to the first end 103A of the housing part 102 and gasification gas having cool temperature, such as between 200 °C and 300 °C, may be supplied from at least from one other nozzle layer. Alternatively or in addition, different gasification gas may be sup25 plied from different nozzle layers as described above in order to keep the temperature substantially constant within the oxidation zone 206.

If the process conditions, such as the output of the product gas or the properties of the fuel, change even further, the gasifier 100 may be adjusted further in order to keep the temperature within the oxidation zone 206 substantially con30 stant and to provide substantially uniform and high quality product gas. Figure

3C illustrates the gasifier 100 according to an embodiment of the present invention, wherein the gasifier 100 is configured to operate at the minimum output of the product gas. The center nozzle part 106 is in a third position and only one or some of the plurality of nozzle layers is configured to be in operation.

In the third position the center nozzle part 106 is in its extreme position closest to the second end 103B of the housing part 102. When the center nozzle part

20165593 prh 16-10-2018

106 is in the third position, the functional cross sectional area of at least one plane of the throat section 104 is at its minimum. Preferably, the functional cross sectional area of at least one plane of the throat section 104 may be decreased 20 percent from its maximum. Furthermore, if the facing surfaces of 5 the substantially cone-shaped section 106A and the sub-section 104A of the throat part are parallel and the center nozzle part 106 is in the third position, the volume of the throat section 104 may be decreased 20 percent from its maximum, for example. In addition, the velocity of the product gas may be increased when the center nozzle part 106 is configured to move from the first 10 position to the third position. Preferably, the velocity of the product gas may be adjustable between 10 meters per minute and 40 meters per minute. Furthermore, by moving the center nozzle part 106 between first and third positions the flow of the product gas can be changed by 20 percent without changing the velocity of the product gas in the throat section 104. Furthermore, the distance 15 D between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 is decreased. When the center nozzle part 106 is in the third position the distance D may be 420 millimeters, for example.

The above described examples illustrated in Figures 3A-3C are only exemplary 20 situations and the position of the center nozzle part 106 may be arranged to be continuously moved between the first position and third position that are the extreme positions of the center nozzle part 106. The distance between the extreme positions of the center nozzle part 106 may be 500 millimeters, for example. Furthermore, the number of nozzle layers that are configured to be in 25 operation may continuously be adjusted as described above.

Gasification gas may be supplied to the plurality of the nozzle layers of the throat section 104 with a common inlet 114. Alternatively or in addition, at least one of the plurality of nozzle layers of the throat section 104 may be provided with own inlet 114A-114N in order to provide gasification gas to the nozzles of 30 said at least one of the plurality of nozzle layers. Figure 4 illustrates an example, where each of the plurality of nozzle layers of the throat section 104 is provided with own inlet 114A-114N. Preferably, each of the plurality of nozzle layers of the throat section 104 may be provided with own inlet 114A-114N in order to supply gasification gas from the plurality of nozzle layers independent35 ly from each other. The inlet 114A-114N may be a pipe or a jacket circulating

20165593 prh 16-10-2018 around the gasifier 100, for example. The gasification gas may be provided from an inlet to the nozzles via a conduit, for example, as shown in Figure 4.

Similarly, gasification gas may be supplied to the plurality of the nozzle layers of the center nozzle part 106 with a common inlet 115. Alternatively or in addi5 tion, at least one of the plurality of nozzle layers of the throat section 104 may be provided with own inlet in order to provide gasification gas to the nozzles of said at least one of the plurality of nozzle layers. Preferably, each of the plurality of nozzle layers of the center nozzle part 106 may be provided with own inlet in order to supply gasification gas from the plurality of nozzle layers inde10 pendently from each other. The inlet may be a pipe or a jacket circulating around the gasifier 100, for example. The gasification gas may be provided from the inlet to the nozzle via a conduit, for example, as shown in Figure 4.

The gasifier 100 according to the present invention enables at least partly improved adjustability of the gasifier 100. Thus also the operation of the gasifier 15 100 may be at least partly improved. The adjustability of the gasifier 100 enables fast adaptation to the changes in the process conditions, such as output of the product gas or properties of the fuel. Thus, the gasifier 100 may provide continuously substantially uniform and high quality product gas. The properties of the fuel may be moisture content and particle size, for example. The adjust20 ability of the gasifier 100 according to the present invention is based on that the center nozzle part 106 is configured to be movable along the direction of the center axis 116 of the housing part 102 in order to adjust a functional cross sectional area of at least one plane of the throat section 104. Furthermore, the movable center nozzle part 106 enables that the distance D between the plu25 rality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles

302 of the throat section 104 may be adjusted continuously in order to at least partly prevent formation of a cold zone between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104. In addition, the plurality of nozzles arranged to form a plurality of nozzle 30 layers on the center nozzle part 106 and/or on the throat section 104 so that the plurality of nozzle layers is arranged to supply gasification gas independently from each other enables that the length of the oxidation zone 206 in the direction of the center axis 116 of the housing part 102 may be adjusted continuously. Alternatively or in addition, as a consequent of adjustment of the 35 length of the oxidation zone 206 the length of the at least one of the other zones may be adjusted. Alternatively or in addition, also the location of the

20165593 prh 16-10-2018 boundary between the oxidation zone 206 and the pyrolysis zone 204 and/or reduction zone 208 may be adjusted through controlling of the operation of the gasifier. The adjustment of the length of the oxidation zone 206 in the direction of the center axis 116 of the housing part 102 enables that process conditions 5 of the gasification process may be adjusted continuously according to the need of output of the product gas and properties of the fuel. The use of plurality of nozzle layers together with the movable center nozzle part 106 enable that the process conditions may be variously adjusted within the oxidation zone 206. When the oxidation zone 206 is long, the process conditions may be adjusted 10 so that the gasification process produces for example product gas having high heating value or so that the amount of at least one the formed product gas element, such as hydrogen, carbon monoxide, methane, may be adjusted.

Figure 5A illustrates the functional cross sectional area 502 of an example plane of the throat section 104, wherein the center nozzle part 106 is in the 15 first position. Figure 5B illustrates the functional cross section area 502 the example plane of the throat section 104, wherein the center nozzle part 106 is in the third position. As shown in Figures 5A and 5B the functional cross sectional area of at least one plane of the throat section 104 is reduced, when the center nozzle part is moved from the first position to the third position.

Above it is described that at least the substantially cone-shaped section 106A of the center nozzle part 106 is symmetrical and concentric with the housing part 102 in the direction of the center axis 116 of the housing part 102. Alternatively, according to an example embodiment of the present invention the center nozzle part 106 may be arranged slightly offset from the center axis 116 of the 25 housing part 102. The offset may be between 20 and 75 millimeters, for example. Accordingly, the functional cross sectional area of at least one plane of the throat section 104 may be defined as an eccentric ring-shaped area between the center nozzle part 106 and the inner surface of the housing part 102 forming the throat section 104, when the center nozzle part 106 reaches to the at 30 least one plane of the throat section 104. In addition, the center nozzle part 106 may be configured to be rotated eccentrically around the center axis 116 of the housing part 102 in order to at least partly prevent or remove the bridging of the fuel. Alternatively or in addition, the substantially cone-shaped section 106A may comprise a plurality of small protrusions on the surface of the cone-shaped section 106A in order to at least partly prevent or remove the

20165593 prh 16-10-2018 bridging of the fuel. The size of the plurality of protrusions may be from 25 to millimeters, for example.

The term “substantially cone-shaped” is used in this patent application to mean a cone-shaped part that may have substantially straight surface(s) or sur5 face(s) that differs from a straight surface(s). The surface(s) differing from a straight surface(s) may be, for example, a curved surface(s), as illustrated in an exemplified manner in Fig. 6.

The term “truncated substantially cone-shaped” is used in this patent application to mean a truncated cone-shaped part that may have substantially straight 10 surface(s) or surface(s) that differs from a straight surface(s). The surface(s) differing from a straight surface(s) may be, for example, a curved surface(s), as illustrated in an exemplified manner in Fig. 6.

Above it is described a gasifier according to the present invention with different embodiments. Moreover, the present invention relates also to a method for ad15 justing an operation of a gasifier 100 according to the invention described above. The method comprises moving the center nozzle 106 along the direction of the center axis 116 of the housing part 102 in order to adjust a functional cross sectional area of at least one plane of the throat section 104. Furthermore, moving the center nozzle part 106 along the direction of the center axis 20 116 of the housing part 102 enables adjusting the distance D between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104 continuously in order to at least partly prevent formation of a cold zone between the plurality of nozzles 304 of the center nozzle part 106 and the plurality of nozzles 302 of the throat section 104. Al25 ternatively or in addition, the method may further comprise supplying gasification gas from the plurality of nozzle layers independently from each other.

The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above 30 are not exhaustive unless otherwise explicitly stated.

Claims

Carburetor (100), characterized in that the carburetor (100) comprises:

- a first end (103A) and a second end (103B) of a cylindrical housing part (102) having a central shaft (116) in the longitudinal direction of the housing part (102), where fuel is fed into the housing part (102) from the first end (103A) ,

- a throat portion (104) formed on the inner surface of the housing portion (102) between the first end (103A) and the second end (103B), wherein the throat portion (104) comprises at least a truncated substantially conical sub-portion (104A) which tapers the housing portion ( 102) towards the other end (103B), wherein a plurality of nozzles (302) are provided on the sub-section (104A) for supplying gasification gas, and

- a central nozzle portion (106) comprising a substantially conical portion (106A) having a surface facing the sub-portion (104A) and a substantially conical portion (106A) comprising a plurality of nozzles (304) for supplying gasification gas, the central nozzle portion (106) being configured to be movable along the direction of the central axis (116) of the portion (102) for adjusting the functional cross-sectional area of at least one plane of the throat portion (104), wherein the gasification gas supplied from the plurality of nozzles (302, 304) forms an annular oxidation zone.

The carburetor (100) of claim 1, wherein the plurality of nozzles (302, 304) are arranged to form a plurality of nozzle layers in at least one of a central nozzle portion (106), a throat portion (104A), each of the plurality of nozzle layers comprising at least two nozzles.

The carburetor (100) of claim 2, wherein the plurality of nozzle layers are arranged to supply the gasification gas independently of each other.

A carburetor (100) according to claim 2 or 3, wherein at least one of the plurality of nozzle layers is arranged to supply a different gasification gas than the others of the plurality of nozzle layers.

A carburetor (100) according to any one of claims 2 to 4, wherein at least one of the plurality of nozzle layers is arranged to supply a gasification gas having different properties or different temperature and / or pressure and / or velocity.

A carburetor (100) according to any one of claims 2 to 5, wherein the length of the oxidation region in the direction of the central axis (116) of the housing part (102) is arranged to be adjustable by supplying gasification gas from one or more nozzle layers.

A carburetor (100) according to any preceding claim, wherein the size of the plurality of nozzles (302, 304) is arranged to be infinitely adjustable.

A carburetor (100) according to any preceding claim, wherein the shape of the plurality of nozzles (302, 304) is arranged to be infinitely adjustable.

A carburetor (100) according to any preceding claim, wherein the gasification gas is any gas comprising oxygen.

A carburetor (100) according to any preceding claim, wherein the carburetor (100) further comprises a grate (108) disposed between the throat portion (104) and the other end (103B) of the housing portion (102), wherein the grate (108) is arranged to be steplessly adjustable in the direction of the central axis (116) of the housing part (102).

A carburetor (100) according to any preceding claim, wherein the carburetor (100) further comprises fuel supply means (110) for supplying fuel within the housing portion (102).

A carburetor (100) according to any preceding claim, wherein the central nozzle portion (106) is arranged to deviate from the central axis (116) of the housing portion (102) and the central nozzle portion (106) is configured to be eccentrically rotatable by the central axis (116) of the housing portion (102). around.

A method of controlling the operation of a carburetor (100) according to any one of claims 1 to 12, characterized in that the method comprises:

- moving the central nozzle part (106) along the direction of the central axis (116) of the housing part (102) to adjust the functional cross-sectional area of at least one plane of the throat part (104).

The method of claim 13, wherein the method further comprises:

- supplying gasification gas from a plurality of nozzle layers independently, wherein the plurality of nozzles (302, 304) form a plurality of nozzle layers in at least one of a central nozzle portion (106), a throat portion (104A), each of the plurality of nozzle layers comprising at least two nozzles.