Abstract:
Disclosed is a multi-burner gasification reactor for gasification of slurry or pulverized hydrocarbon feed materials and industry applications thereof. Burners are disposed on the periphery or top of a gasification reactor vessel, wherein the side burners are at a small downward angle relative to the horizontal plane, which can prolong the life of refractory bricks. The operating pressure of the gasification reactor is 0.1˜12 MPa, and the operating temperature thereof is 1350° C.˜1700° C. The gasification reactor is applicable to a hot-wall lining as well as a cold-wall lining. The notable advantages of the gasification reactor are carbon conversion is high and can reach 99%, and the effective gas content is high; specific coal consumption and specific oxygen consumption are low; and it is applicable to a large coal gasification plant that processes above 3000 tons of coal per day.

Description:
This application claims priority to Chinese Patent Application No. 200610119511.0 filed on Dec. 12, 2006 the contents whereof are hereby incorporated. 
     FIELD OF THE INVENTION 
     This invention relates to gasification equipment of hydrocarbon materials, and, more specifically to a multi-burner gasification reactor fed with slurry or pulverized hydrocarbon materials. 
     BACKGROUND OF THE INVENTION 
     With the development of human society, the bottleneck of energy and environment protection appears gradually, for which people have spent painstaking effort so that energy-related equipment has been increasingly perfected. Gasification reactors have also been developed from original fixed-beds (1920s) and fluidized-beds (1930s) to recent entrained-beds. The typical entrained-bed gasification technologies are GE gasification (former Texaco gasification, U.S. Pat. Nos. 4,637,823, 4,527,997, 5,281,243) and Shell gasification (U.S. Pat. No. 4,799,356). The former is fed with slurry state materials and the latter is fed with pulverized state materials. Some drawbacks of current gasification technologies have appeared in practical applications. For example, GE gasification drawbacks include low carbon conversion (only 94˜95%), low effective gas content (78˜81% of (CO+H 2 ) when fed with coal-water slurry), limited life of refractory bricks near a syngas and slag outlet (only 2000˜3000 hours). The above drawbacks are mainly caused by unreasonable setting of gasification burners. The gasification burner is set at the center line of the top of the gasification reactor vessel, so the residence time distribution of the materials in the reactor is relatively wide, ranging from the shortest 0.01 s to the longest 32 s. The flow field and velocity distribution of GE gasification reactor are shown in  FIG. 1 , in which the flow field can be divided into three regions: jet-flow region (I), recirculation-flow region (II) and plug-flow region (III). The materials with short residence time are discharged from the gasification chamber before completion of chemical reactions, which is the ultimate reason for low carbon conversion. Shell gasification drawbacks are: the syngas from the gasification reactor is cooled by recycled clean syngas, and the ratio of the recycled clean syngas to the syngas from the gasification reactor is 0.8; with the same treatment capacity, investment of Shell gasification is more than two times that of the GE gasification; and the gasification reactor is very complex. Shell gasification adopts multiple burners too, but the setting of the burners is not reasonable, which results in large amount of dusts being carried out of the gasification reactor. To increase carbon conversion, Shell gasification adopts return dusts and the setting of burners is also very complex, including startup burner, gasification burner, etc. Even now, different kinds of problems often occur in the Shell gasification plants such as Shuanghuan (Hubei Province) and Anqing (Anhui Province) in China. In view of the above, it is highly desirable in the art that a gasification reactor with better performance be invented. 
     The object of this invention is to disclose a multi-burner gasification reactor for gasification of slurry or pulverized hydrocarbon feed materials and industry applications thereof, which can eliminate the above drawbacks. 
     SUMMARY OF THE INVENTION 
     The conception of this invention is as follow: 
     On the basis of over 20 years of research in the gasification field, the inventors bring forward the conception of a multi-burner gasification reactor, which has the following main features: 
     (1) For the gasification reactions of hydrocarbon materials under high temperature and pressure, the controlled processes are diffusion and mixing which should be reinforced; 
     (2) To narrow the distribution of residence time of materials in the gasification reactor (namely, to achieve more reasonable distribution) to increase carbon conversion, appropriate flow field and velocity distribution are necessary, shown in  FIG. 2  and  FIG. 3 , wherein  FIG. 3  is an A-A schematic view of  FIG. 2 . The flow field can be divided into six regions: jet-flow region  101 , impinging region  102 , impinging-flow region  103 , recirculation-flow region  104 , reentry-flow region  105  and plug-flow region  106 ; 
     (3) To ensure the life of the refractory bricks at the top of the gasification reactor, such as over 8000 hours, impinging flows should have a small downward angle; 
     (4) To overcome the effect of thermal expansion of the refractory bricks on burner displacement, brick-supporters should be provided. Simultaneously the brick-supporters can play a role in protection of a thermometric element (namely thermocouples); 
     (5) The syngas and slag outlet of the gasification chamber should be enlarged to make sure that the gasification reactor is applicable to the gasification of high ash content hydrocarbon materials, such as sludge. 
     Gasification processes take place in the following manner: Slurry or pulverized hydrocarbon materials are injected into the gasification reactor through a special passage, while a gasifying agent (pure oxygen) and steam (only used in pulverized mediums) are injected into the gasification reactor through the special passage too. Oxygen (or together with H 2 O) is injected with a velocity of 30˜200 m/s. Burners are set in pairs and meet at 180 degrees, thus forming an impinging-flow. Since every stream has a slightly downward angle (1˜10 degrees), the upward velocity of the impinging-flow is decreased, which can ensure the life of the refractory bricks at the top of the gasification reactor. In the gasification chamber, main chemical reactions among hydrocarbon material, oxygen and steam are listed as follows:
 
C+O 2 ═CO 2   (1)
 
C+H 2 O═CO+H 2   (2)
 
C+CO 2 ═CO  (3)
 
CO+H 2 O═CO 2 +H 2   (4)
 
C+2H 2 ═CH 4   (5)
 
     According to the above conception, this invention discloses a multi-burner gasification reactor for gasification of slurry or pulverized hydrocarbon feed materials. Said multi-burner gasification reactor includes: 
     an upright cylindrical vessel including a refractory lining layer therein; 
     a brick-supporting plate, disposed at the middle of the upright vessel, dividing the upright vessel into two parts: an upper gasification chamber and a lower scrubbing and cooling chamber; 
     n pairs (2≦n≦10) of gasification burner chambers disposed on the periphery of said gasification chamber, each pair of which is symmetrically opposed and meets at 180 degrees, the axis of which is at an angle of 1˜10 degrees relative to the horizontal plane, which locate at the horizontal plane where the distance (H) between the gasification burner planes and the top of the reactor vessel is 1˜2 times the inner diameter (D i ) of the gasification reactor, and which can be set as one, two or three layers, and the gasification burner chamber disposed on the top of said gasification chamber being parallel to the axis of the gasification reactor; 
     gasification burners disposed in the gasification burner chambers, the gasification burners being coaxial with the gasification burner chambers and being used to introduce the slurry or pulverized hydrocarbon materials into the gasification reactor and to mix them well for gasification reactions; 
     the refractory lining can be a cold-wall lining, e.g. the technology disclosed in Chinese Pat. No. ZL 200410067212.8, or a hot-wall lining, e.g. the technology disclosed in Chinese Pat. No. ZL 98110616.1; 
     brick-supporters disposed in the refractory brick lining layer; 
     a syngas and slag outlet disposed in the center of the supporting-plate, wherein high temperature syngas and melted ash concurrently flow through the syngas and slag outlet, and the high temperature syngas can well carry the flow of the high viscous melted ash; 
     a water jacket disposed on the back of the brick-supporting plate, wherein cooling water enters from the bottom of the water jacket and overflows from the top; 
     a syngas and slag tube disposed at the lower of the syngas and slag outlet and inserted in the scrubbing and cooling chamber; 
     a cooling water ring disposed at the center of the brick-supporting plate and fixed to said brick-supporting plate, wherein water spouting from the cooling water ring chills the high temperature syngas and the melted ash to protect the syngas and slag tube from ablating; 
     bubble-breaking plates disposed inside the scrubbing and cooling chamber and out of the syngas and slag tube, wherein the bubble-breaking plates are fixed on the inner side of the gasification reactor vessel by a bubble-breaking plate shelf, and there is some gap between the bubble-breaking plates and the syngas and slag tube, the purpose of the bubble-breaking plates being to break big bubbles and enhance contacting effect of liquid and solid; 
     a syngas outlet disposed at the upper portion of the scrubbing and cooling chamber; 
     a black water outlet disposed at the lower portion of the scrubbing and cooling chamber; 
     a slag water outlet disposed at the bottom of the scrubbing and cooling chamber; 
     a high pressure nitrogen blowing pipe disposed at the lower portion of the scrubbing and cooling chamber and inside the syngas and slag tube to blow high pressure nitrogen at regular intervals to remove possible ash accumulated at the syngas and slag outlet in the center of the brick-supporting plate; 
     The fire-end profile of the gasification chamber is bell mouth, and the end of the gasification burners is shorter than the refractory lining to prevent the melted ash from blocking the burners after it flows down. 
     The gasification burners are multi-channel ones, which can adopt multiple burner styles such as internal mixing or external mixing. For example, for slurry hydrocarbon materials, technology disclosed in Chinese Pat. No. ZL 95111750.5 can be used, and for pulverized hydrocarbon materials, technology disclosed in Chinese Pat. No. ZL 200420114032.6 can be used. The objective of this invention also can be achieved with burners of other kinds, such as the cluster-burner shown in Chinese Pat. Application No. 200610116588.2. 
     The multi-burner gasification reactor in this invention can be used to gasify slurry or pulverized hydrocarbon materials, which can be coal, petroleum coke, biomass, waste and other solid hydrocarbon materials. 
     The slurry or pulverized hydrocarbon materials (such as coal) with particle diameter smaller than 200 μm are conveyed to the gasification burners, the slurry hydrocarbon materials via a high pressure pump and the pulverized hydrocarbon materials via a carrier gas such as nitrogen or carbon dioxide, respectively. Gasifying agents enter the gasification burner and the mixture of these gasification agents is then injected out of the gasification burner at 30˜200 m/s. An impinging stream is formed by the multiple opposed and slightly downwards-inclined gasification burners, which can intensify mixing and diffusion. Then atomized or dispersed hydrocarbon materials are gasified to produce syngas in the gasification chamber. The high temperature syngas, together with melted ash, enters the scrubbing and cooling chamber to remove ash and then syngas enters the downstream syngas treating units through the syngas outlet. Slag is discharged through the slag water outlet and the black water goes to the downstream water treating units through the black water outlet. 
     The gasification temperature is 1350° C. (hot-wall) ˜1700° C. (cold-wall), and the gasification pressure is 0.1˜12 Mpa. Carbon conversion of hydrocarbon materials is 99%, and the effective gas (hydrogen and carbon monoxide) content in the syngas outlet is 80˜94%(depending on the kind and the state of feed); 
     For each part of hydrocarbon material by weight, the gasification agent should be 0.4˜1.2 parts, and steam 0˜0.5 parts; 
     The gasification agents include oxidant, steam and carbon dioxide; 
     The oxidant is selected from the group consisting of oxygen, air and the oxygen-enriched air with 60˜70% oxygen content; 
     The weight ratio of the carrier gas (e.g. nitrogen and carbon dioxide) and the hydrocarbon materials is that for each part of the carrier gas, the hydrocarbon materials should be 0.02˜0.8 parts; 
     Compared with the current gasification reactors that have been disclosed, this multi-burner gasification reactor shows the significant advantages that the carbon conversion rate is high and can reach 99%, the effective gas content is high; the specific coal consumption and the specific oxygen consumption are low; the distribution of temperature in gasification reactor is homogeneous, so the ablation of the refractory lining caused by local partial high temperature does not happen and the life of the refractory lining is long; this gasification reactor is applicable to a large gasification plant that processes above 3000 tons of coal per day. The syngas produced, which can be used as the raw materials of chemicals, fuel gas, IGCC power generation, hydrogen, synthetic liquid fuel and DRI etc, has wide applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flow field and velocity distribution diagram of a former Texaco gasification reactor; 
         FIG. 2  is a flow field and velocity distribution diagram of the multi-burner gasification reactor of the present invention; 
         FIG. 3  is a schematic view of  FIG. 2  in the A-A direction; 
         FIG. 4  shows a multi-burner gasification reactor for gasification of slurry or pulverized hydrocarbon feed materials; 
         FIG. 5  is a top view of  FIG. 4 ; 
         FIG. 6  is a schematic view showing the structure of a cluster-burner. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to  FIG. 4  and  FIG. 5 , the multi-burner gasification reactor for gasification of slurry or pulverized hydrocarbon feed materials provided by this invention comprises: 
     an upright cylindrical vessel  1  having a refractory lining therein; 
     a brick-supporting plate  6 , set in the middle of the vertically cylindrical vessel  1 , dividing said upright cylindrical vessel  1  into an upper gasification chamber  2  and a lower scrubbing and cooling chamber  3 ; 
     n pairs (2≦n≦10) of gasification burner chambers  5  set on the side of said gasification chamber  2 , each pair of which is symmetrically opposed and meets at 180 degrees, the axis of which has a 1˜10 degrees downward angle relative to the horizontal plane, which locate at the planes whose distance (H) to the top of the reactor vessel is 1˜2 times the inner diameter (D i ) of the reactor vessel, and which can be set as one, two or three layers. In addition to being set on the periphery of said gasification chamber  2 , the gasification burner chamber  5  also can be set at the top of the gasification reactor vessel  1 , in which the gasification burner chamber  5  is parallel to the axis of the gasification reactor vessel  1 . 
     The gasification burner  7  set in the gasification burner chamber  5  is coaxial with the gasification burner chamber  5 . The gasification burners  7  are used to introduce the slurry or pulverized hydrocarbon materials into gasification chamber  2  and to mix them well, for gasification reactions; 
     A stoving burner chamber  8  set at the center of the top of the gasification reactor vessel  1 , which serves to install a stoving burner to increase temperature of the gasification reactor. When stopping heating, the stoving burner is pulled out and is replaced by a plug cap  9 . Said plug cap  9  is a truncated cone cylinder made of refractory materials and includes a cooling coil and steel bars inside; 
     The refractory lining  4  can be a cold-wall lining or a hot-wall lining; 
     Brick-supporters are set in the refractory brick lining  4 , which is composed of a brick-supporter shelf  16  and a ring round plate  22  set on the brick-supporter shelf  16 . The number of the layers of the brick-supporter is 1˜4, and the peripheries of said brick-supporter shelf  16  and said ring round plate  22  are lined with refractory fibers. 
     Strip cooling fins  17  are set outside of the gasification reactor vessel  1  where the brick-supporter shelf  16  is set, each brick-supporter shelf  16  corresponding to one strip cooling fin  17 . The strip cooling fin  17  and the brick-supporter shelf  16  are of the same height. 
     The syngas and slag outlet  24  is set in the center of the brick-supporting plate  6 , and the flow area of the syngas and slag outlet  24  is designed based on a medium flow rate of 5-10 m/s. The high temperature syngas and melted ash concurrently flow through the syngas and slag outlet. The high temperature syngas can well carry the flow of the high viscous melted ash. 
     A water jacket  14  is set on the back of the brick-supporting plate  6 . The cooling water enters from a water inlet  23  at the bottom of the water jacket and overflows from the top. 
     A syngas and slag tube  11  is set at the lower portion of said syngas and slag outlet  24  and inserted into the said scrubbing and cooling chamber  3 . The syngas and slag tube  11  is coaxial with the gasification reactor. 
     A cooling water ring  10  is set at the center of the brick-supporting plate  6  and fixed to said brick-supporting-plate  6 . The water spouting from the cooling water ring  10  chills the high temperature syngas and the melted ash to protect the syngas and slag tube  11  from ablating; 
     Bubble-breaking plates  12  are set in the scrubbing and cooling chamber  3  and at the outer of said syngas and slag tube  11 . Said bubble-breaking plates  12  are fixed at the inner side of the gasification reactor vessel  1  through a bubble-breaking plate shelf  18  and keeps a gap from the outer side of the syngas and slag tube  11 . 
     A syngas outlet  13  is set at the upper portion of said syngas scrubbing and cooling chamber  3 . 
     A black water outlet  19  is set at the lower portion of said syngas scrubbing and cooling chamber  3 . 
     A slag water outlet  15  is set at the bottom of said syngas scrubbing and cooling chamber  3 . 
     A high pressure nitrogen blowing pipe  21  is set at the lower portion of the scrubbing and cooling chamber  3  and inside the syngas and slag tube  11 , at the head of which there is a high pressure nitrogen nozzle  20  to blow high pressure nitrogen at regular intervals, so as to remove possible ash accumulated at the syngas and slag outlet  24  at the center of the supporting-plate  6 . 
     Referring to  FIGS. 4 and 5 , the fire-end profile of said gasification burner chamber  5  is bell mouth. The included angle of said bell mouth is 20˜60 degrees. The end of the gasification burners  7  is 20˜200 mm shorter than that of the refractory lining to prevent the melted ash from blocking the burners after it flows down. 
     The gasification burners are multi-channel ones, which can adopt multiple burner styles such as internal mixing or external mixing. For example, for slurry hydrocarbon materials, technology published by Chinese Pat. No. ZL 95111750.5 can be used, and for pulverized hydrocarbon materials, technology published by Chinese Pat. No. ZL 200420114032.6 can be used. The objective of this invention also can be achieved with burners of other styles. The inventors preferably recommend a type of cluster-burner as disclosed in Chinese Pat. Application No. 200610116588.2, the entirety of which is incorporated herewith by reference. As shown in  FIG. 6 , the cluster-burner comprises a housing  25  and N burners  26  (N&gt;1) within the housing  25 , the burners  26  being preferably set vertically in the housing  25  and preferably having their axes parallel with each other. 
     The burner  26  comprises an outer sleeve  27 , an inner sleeve  28  set in the outer sleeve  27 , a lower pipe sheet  29 , an upper pipe sheet  30  and a cooling chamber  31 . 
     The cooling chamber  31  is set at the outlet  32  of the burner  26 . The cooling chamber  31  comprises a U-type encloser  33  which is fixed to the housing  25 , a cover plate  34  which is set at the upper of the U-type encloser  33 , a cooling water inlet conduit  35  and a water outlet conduit  36  which are both set on the cover plate  34 . It is preferable for the inlet conduit  35  to be inserted into the inner bottom surface of the U-type encloser  33 , and it is preferable for the outlet conduit  36  to be set near the cover plate  34 . The cooing water in the cooling chamber  31  can flow with revolution to improve heat transfer. 
     A position-setting plate  37  is set in the intermediate section of the housing  25  in order to restrict the vibration of the burner  26  in working. 
     A coal-slurry or other hydrocarbon materials inlet  38  and a gasification agent inlet  39  are both set at the upper portion of the housing  25 . The coal-slurry or other hydrocarbon materials inlet  38  communicates with the inner sleeve  28 , and the gasification agent inlet  39  communicates with the outer sleeve  27 . 
     The advantages of the cluster-burner are as follows: Because the flame is relatively short and tends to be rectangular, it is helpful to protect the refractory brick lining at the intermediate or lower portion of the gasification reactor and increase its life. Because the residence time distribution is narrow, it is helpful to increase carbon conversion; Because of the reasonable structure of the cluster-burner, it is helpful to increase the life of the burner. 
     Example 1 
     A multi-burner gasification reactor shown in  FIG. 1  was used, for which the gasification materials was coal-water slurry, the throughput is 125 t/h coal (3000 t/d coal), the flow rate of coal-water slurry was 210 t/h, the gasification pressure was 6.5 MPa, the hot-wall lining was used, the gasification temperature was 1350° C., the total height of the gasification reactor was 21 m including a gasification chamber with a height of 11 m and a scrubbing and cooling chamber with a height of 10 m, the inner diameter of the gasification chamber vessel was 5.6 m, and 4 layers of bubble-breaking plates were set in the scrubbing and cooling chamber. 
     Four opposed gasification burner chambers were set symmetrically at the upper portion of the gasification chamber. The distance between the gasification burner chamber and the top of the gasification reactor was 1.5 times the size of the inner diameter of the gasification chamber vessel; the axis of the gasification burner chambers made an angle of 5 degrees with the horizontal plane; the fire-end of the gasification burner chambers  5  was a bell mouth with an included angle of 30 degrees; the fire-end of the gasification burner was 100 mm shorter than that of the refractory lining. 
     The burner was a type of cluster-burner (Chinese Pat. Application No. 200610116588.2). For cluster-burner, the external diameter of the housing  25  was 260 mm and seven burners  26  were set. The diameter of the inner sleeve was 31−3 mm, and the diameter of the outer sleeve was 39.6×3 mm. The tube pitch of the outer sleeves was 80 mm. The total length of the cluster-burner was 2000 mm. The jet velocity of the coal-water slurry in the inner sleeve was about 4 m/s and about 125 m/s in the outer sleeve. 
     The coal-water slurry with particle diameter of 30-100 μm at a mass flow rate of 210 t/h and oxygen with 99% oxygen content at a flow rate of 97000 Nm 3 /h were divided evenly into 4 shares, and then were introduced into the gasification chamber by four cluster-burners. After the processes of combustion and gasification reactions in the gasification reactor under the operating pressure of 6.5 MPa and the temperature of 1350° C., the hydrogen and carbon monoxide in syngas with a flow rate of 212500 Nm 3 /h was produced. The high temperature syngas and melted ash were discharged concurrently out of the gasification chamber through the syngas and slag outlet. 
     The high temperature syngas, together with melted ash, entered the scrubbing and cooling chamber to remove ash and then syngas entered the downstream syngas treating units through a syngas outlet. Coarse slag was discharged from the gasification reactor to slag discharge equipment, and black water also went to the downstream water treating units through a black water outlet. 
     The composition of syngas is as follow: 37% H 2 , 47.5% CO, 14% CO 2 , 0.6% N 2 , and a little H 2 S, Ar, COS, CH 4 , HCN and NH 3 . The syngas can be used to produce fertilizer, methanol, hydrogen, liquid fuel, fuel gas, DRI, to generate electricity, etc., or used in advanced IGCC power generation and poly-generation system. 
     Example 2 
     The opposed multi-burner gasification reactor shown in  FIG. 1  was used, for which the gasification reactor with pulverized coal had a throughput of 100 t/h (2400 t/d) coal, the gasification pressure was 4.0 MPa, the refractory lining of the gasification reactor was water screen, the gasification temperature was 1600° C., the total height of the gasification reactor was 22 meters including a gasification chamber with a height of 12 m and a scrubbing and cooling chamber with a height of 10 m, the inner diameter of the gasification chamber was 2.5 meters, and 4 layers of bubble-breaking plates were set in the scrubbing and cooling chamber. 
     Four opposed gasification burner chambers were set symmetrically at the upper portion of the gasification chamber. The distance between the gasification burner chamber and the top of the gasification reactor was 1.5 times the size of the inner diameter of the gasification chamber vessel; the axis of the gasification burner chambers made an angle of 4 degrees with the horizontal plane; the fire-end of the gasification burner chambers  5  was a bell mouth with an included angle of 30 degrees; the fire-end of the gasification burner was 100 mm shorter than that of the refractory lining. 
     The burner described by Chinese Pat. No. 200420114032.6 was chosen as the gasification burner. 
     The pulverized coal with particle diameter of 30-100 μm at a mass flow rate of 100 t/h coal, pure oxygen with 99% oxygen content at a flow rate of 60000 Nm 3 /h and superheated steam with a flow rate of 72 t/h and a temperature of 430° C., were divided evenly into four shares, and introduced into the gasification chamber by four burners. Then combustion reaction and gasification reaction occurred under the operating pressure of 4.0 MPa and the operating temperature of 1600° C. in the gasification chamber. Finally the hydrogen and carbon monoxide in syngas with a flow rate of 190000 Nm 3 /h was produced. The high temperature syngas and melted ash were concurrently discharged out of the gasification chamber through the syngas and slag outlet. 
     The high temperature syngas, together with melted ash, entered the scrubbing and cooling chamber to remove ash and then syngas entered the downstream syngas treating units through a syngas outlet. Coarse slag was discharged from the gasification reactor to slag discharge equipment, and black water also went to the downstream water treating units through a black water outlet. 
     The composition of syngas is as follow: 31% H 2 , 59% CO, 4% CO 2 , 5% N 2 , and a little H 2 S, Ar, COS, CH 4 , HCN and NH 3 . The syngas was used to produce fertilizer, methanol, hydrogen, liquid fuel, fuel gas, DRI, electricity generation, or advanced IGCC power generation and poly-generation system. 
     The preferred embodiments of the invention have been described in detail as above. However, it shall be appreciated that, without departing the spirit of the invention, numerous amendments, changes and modifications are possible to a skilled person in the art. Therefore, the scope of the invention is solely intended to be set out in the claims.