Field of the Invention

The present invention relates to the filed of chemical industrial equipment and chemical engineering. In particular, it relates to an

inner-circulating slurry-bed reactor with high efficiency that is used for slurry-bed reaction and a method for conducting a slurry-bed reaction.

Background

In organic chemical synthesis process, gas-liquid-solid three-phase synthesis system that comprises gaseous, liquid and solid reactants simultaneously is very important. For example, slurry-bed reactor for Fischer- Tropsch synthesis is a three-phase reactor for industrial

application. Fischer- Tropsch synthesis is a chemical conversion process to convert synthesis gas (CO+H ₂ ) into hydrocarbon and a small amount of organic oxygen-containing compounds. Its main feature is strong exothermicity. Initially, people tried to use the fixed bed and fluidized bed reactor for Fischer- Tropsch reaction operation. However, the heat transfer efficiency of these reactors is not satisfied, which makes it difficult to control the reaction. Thus, a new slurry-bed reactor is developed. The feature of the slurry-bed reactor is that it includes a liquid slurry layer with small solid particle suspended therein. The gas materials go through said liquid slurry layer in the form of bubbles so that the three phases of solid-liquid-gas contact with each other in appropriate reaction condition and can then complete the three-phase reaction. The liquid phase in the slurry-bed reactor can be either reactant or liquid carrier of the suspended solid catalyst. Compared with the traditional fixed bed and fluidized bed reactors, the slurry-bed reactor could effectively control the reaction temperature and remove the reaction heat while it is easy to be enlarged to large-scale manufacture.

Three-phase slurry-bed is widely used in chemical industrial process and has been reported in literatures and patents currently. For example, Chinese patent 99127184.X provides a gas-liquid-solid three-phase circulating reactor. Chinese patent 03151 109.0 provides a gas-liquid-solid three-phase slurry-bed industrial reactor for continuous operation. Chinese patent 200710037008.5 provides a slurry-bed reactor with internal circulation and outer heat exchange and the application thereof. Chinese patent 101396647A disclosed a gas-liquid-solid three-phase suspension bed reactor for Fischer-Tropsch synthesis. It provides the construction and size design for the reactor, the arrangement and design for air distributor and heat exchanger, wax and catalyst filter system, fluid conduction device in a reactor and foam

elimination device at the top of a reactor. South Africa Sasol company has substantially achieved the industrialization of the slurry-bed reactor

technology (A.M.Steynberg,M.E. Dry,B.H.Davisand B.B.Breman, Studies in Surface Science and Catalysis 152,A.Steynbergand M.Dry(eds.), m64-195, Elsevier B.V.,2004).

However, the Fischer-Tropsch slurry-bed reactors developed in prior art still use the natural bubble or the density difference inside and outside of the fluid conduction cylinder to realize the slurry circulation in the reactors. On one hand, in order to avoid the catalyst sedimentation, agglomeration and inactivation in the reactor due to the slurry circulation shortage, the gas flow rate need to be increased. Meanwhile, to facilitate the mixing intensity and promote the mass and heat transfer efficiency, the reactor needs to be operated under high gas flow rate. On the other hand, if the equipments of prior art are operated under high gas flow rate, the relative slipping rate between the gas and the slurry will be too high. Severe back-mixing will occur and will significantly affect the reaction efficiency. Thus a new three-phase inner-circulating slurry-bed reactor need to be developed to increase the operation gas flow rate through increasing the slurry circulation rate, thereby increasing the space utilization and space time yield and improving the reaction efficiency of the reactor.

Summary of the Invention

With regard to the aforementioned issues, the present invention provides a new slurry-bed reactor. Said reactor comprises a reactor housing (1), and the following components arranged on or in the reactor housing (1): an upper outlet (13), a fluid conduction pipe (17), a lower inlet (12). The fluid conduction pipe (17) is set vertically in the housing and allows slurry-bed slurry to flow in from upper opening of the fluid conduction pipe. The lower inlet (12) is in communication with the slurry-bed receiving space. The upper outlet (13) is used to discharge gas in a chamber, wherein at least one nozzle is provided in said fluid conduction pipe (17) with its opening directed downward or obliquely downward.

In an embodiment of the present invention, the reactor further comprises material drawing outlet (10), the material drawing outlet (10) is used to discharge substances other than gas in the chamber.

In an embodiment of the present invention, the nozzle (19-1) is placed through the wall of the fluid conduction pipe (17), the angle between the opening direction of the nozzle (19-1) and the axial direction of the fluid conduction pipe is 0-90°, preferably 5-45°, more preferably 25-30°. Preferably, multiple nozzles (19-1) are provided in the fluid conduction pipe (17). The nozzles (19-1) are layered along the inner wall of the fluid conduction pipe (17) in a spiral form. 1-8 nozzles are provided in each layer. Preferably, 1 nozzle is provided in each layer. When observed from the top of the fluid conduction pipe (17), the nozzles are arranged evenly around the fluid conduction pipe (17). In an embodiment of the present invention, the angle between the opening direction of the nozzle (19-1) and the wall of the fluid conduction pipe (17) is 0-90° when observed from the top of the fluid conduction pipe (17).

In another embodiment of the present invention, a nozzle with the shape of a shower head (19-2) is provided inside the fluid conduction pipe (17) with its opening directed downward or obliquely downward. Preferably, the nozzle with the shape of a shower head (19-2) is provided along the central axis of the fluid conduction pipe (17). In another embodiment of the present invention, the distance between the lower edge of the nozzle with the shape of a shower head (19-2) and the lower outlet of the fluid conduction pipe (17) is 0-1 meter, preferably 0.5 meter. The angle of the fan-shaped opening of the nozzle with the shape of a shower head is 10^90°, preferably 60°.

In another embodiment of the present invention, the upper end of the fluid conduction pipe (17) comprises a flared opening (18) that has multilayer of parallel circular projections placed on the outer surface of the flared opening (18). The angle between the circular projections and the axial direction of the fluid conduction pipe is 30^80°, preferably 50^70°, most preferably 60°.

In another embodiment of the present invention, a tapered baffle (21) is provided below the fluid conduction pipe (17).

In a preferred embodiment, the reactor further comprises a gas distributor (1 1). The gas distributor (11) comprises a number of short tubes (22) thereon, each of which has a side opening. The angle between the side opening and the axial direction of the fluid conduction pipe is 0°^90°, preferably 45° or 90°.

In another embodiment of the present invention, the reactor further comprises a heat exchange tube. Preferably, the heat exchange tube comprises an upper heat exchange tube (4-1), a middle heat exchange tube (4-2) and a lower heat exchange tube (4-3).

In another embodiment of the present invention, the reactor further comprises a separator (14). A downstream leg (16) extends from the lower part of the separator (14) into the fluid conduction pipe (17). Preferably, the reactor further comprises a separator (14), a separating plate (23) and an extension section (24).

In an embodiment of the present invention, the nozzle can be used for spraying gas, preferably for spraying gas reactants. In another embodiment of the present invention, the reactor can be used for slurry-bed reaction, preferably for Fischer- Tropsch reaction.

In an embodiment of the present invention, the reactor further comprises a slurry bed layer (3). The upper end of the fluid conduction pipe (17) comprises a flared opening (18). The upper edge of the flared opening (18) is located 0.1-1 meter below the fluid level of the slurry bed layer (3), preferably 0.1-0.5 meter below.

In another aspect of the present invention, there is provided a fluid conduction pipe for a slurry-bed reactor, wherein at least one nozzle (19-1) is provided in said fluid conduction pipe with its opening directed downward or obliquely downward. Preferably, the nozzle (19-1) is placed through the wall of the fluid conduction pipe (17). The angle between the opening direction of the nozzle (19-1) and the axial direction is 0-90°, preferably 5-45°, more preferably 25-30°. More preferably, multiple nozzles (19-1) are provided in the fluid conduction pipe. The nozzles (19-1) are layered along the inner wall of the fluid conduction pipe (17) in a spiral form. 1-8 nozzles are provided in each layer. Preferably, 1 nozzle is provided in each layer. When observed from the top of the fluid conduction pipe (17), the nozzles are arranged evenly around the fluid conduction pipe (17). In another preferred embodiment, the angle between the opening direction of the nozzle (19-1) and the wall of the fluid conduction pipe (17) is 0-90° when observed from the top of the fluid conduction pipe (17). In another embodiment of the present invention, a nozzle with the shape of a shower head (19-2) is provided inside the fluid conduction pipe (17) with its opening directed downward or obliquely downward. Preferably, the nozzle with the shape of a shower head (19-2) is provided along the central axis of the fluid conduction pipe (17). In another embodiment of the present invention, the distance between the lower edge of the nozzle with the shape of a shower head (19-2) and the lower outlet of the fluid conduction pipe (17) is 0-1 meter, preferably 0.5 meter. The angle of the fan-shaped opening of the nozzle with the shape of a shower head is 10^90°, preferably 60°. In another embodiment of the present invention, the upper end of the fluid conduction pipe (17) comprises a flared opening (18) that has multilayer of parallel circular projections placed on the outer surface of the flared opening (18). The angle between the circular projections and the axial direction of the fluid conduction pipe is 30^80°, preferably 50^70°, most preferably 60°.

In another embodiment of the present invention, a tapered baffle (21) is provided beneath the fluid conduction pipe (17).

In another embodiment of the present invention, the nozzle can be used for spraying gas, preferably for spraying gas reactants. In another

embodiment of the present invention, the fluid conduction pipe can be used for slurry-bed reaction, preferably for Fischer-Tropsch reaction. The present invention also provides a novel method for conducting the slurry-bed reaction. The method uses a slurry-bed reactor comprising a reactor housing (1) and the following components arranged on or in the reactor housing (1): an upper outlet (13), a fluid conduction pipe (17), a lower inlet (12) and a slurry bed layer (3), and at least one nozzle is provided in said fluid conduction pipe (17) with its opening pointing downward or obliquely downward, said method comprising: i) introducing gas components into the slurry-bed reactor through the lower inlet (12) so that the gas components rise in an annular space between the exterior wall of the fluid conduction pipe (17) and the interior wall of the reactor housing (1), driving the slurry of said slurry bed layer (3) in the annular space to rise with the gas components, and the gas components react in the slurry; ii) the resulting gas products of the reaction and unreacted gas components rise and depart from said slurry bed layer (3), and are expelled from the upper outlet (13) of the slurry-bed reactor while at least a portion of the slurry of the slurry bed layer (3) entering into the fluid conduction pipe (17) through an upper opening of the fluid conduction pipe and flowing down along the fluid conduction pipe (17) and flowing out at the lower outlet of the fluid conduction pipe (17) to the annular space, and the at least one nozzle spraying gas, fluid or slurry; iii) repeating steps (i) and (ii) above.

In an embodiment of the present invention, a number of nozzles (19-1) are provided in the fluid conduction pipe (17) and through the wall of the fluid conduction pipe (17). The angle between the opening direction of the nozzles (19-1) and the axial direction is 0-90°, preferably 5-45°, more preferably 25-30°.

In another embodiment of the present invention, the nozzles (19-1) are layered along the inner wall of the fluid conduction pipe (17) in a spiral form. 1-8 nozzles are provided in each layer. Preferably, 1 nozzle is provided in each layer. When observed from the top of the fluid conduction pipe (17), the nozzles are arranged evenly around the fluid conduction pipe (17). Preferably, the angle between the opening direction of the nozzles (19-1) and pipe wall of the fluid conduction pipe (17) is 0-90° when observed from the top of the fluid conduction pipe (17).

In another embodiment of the present invention, a nozzle with the shape of a shower head (19-2) is provided at the lower end inside the fluid conduction pipe (17). The nozzle is provided along the axis of the reactor with its opening pointing downward. Preferably, the distance between the lower edge of the nozzle with the shape of a shower head (19-2) and the lower outlet of the fluid conduction pipe (17) is 0-1 meter, preferably 0.5 meter. The fan-shaped angle of the opening with the shape of a shower head is 10 90°, preferably 60°.

In another embodiment of the present invention, the fluid conduction pipe (17) comprises a flared opening (18) at the top thereof, multilayer parallel circular projections are provided on the outer surface of the flared opening (18), the angle between the circular projections and the axial direction of the slurry-bed reactor is 30^80°, preferably 50^70°, most preferably 60°.

In another embodiment of the present invention, the slurry-bed reactor further comprises a separating plate (23), an extension section (24), heat exchange tubes (4), a gas distributor (11). In another embodiment of the present invention, a tapered baffle (21) is provided at the lower part of the fluid conduction pipe (17).

In another embodiment of the present invention, the gas distributor (11) comprises a number of short tubes (22) thereon, each of which has a side opening. The angle between the opening and the axial direction is 45^90°, preferably 45° or 90°.

In another embodiment of the present invention, the heat exchange tubes comprises upper heat exchange tubes (4-1), middle heat exchange tubes (4-2) and lower heat exchange tubes (4-3), each of which comprises an inlet (5, 7, 9) and an outlet (2, 6, 8), respectively.

In another embodiment of the present invention, the upper end of the fluid conduction pipe (17) comprises a flared opening (18). The upper edge of the flared opening (18) is located at 0.1-1 meter below the fluid level of the slurry bed layer (3), preferably 0.1-0.5 meter below.

In another embodiment of the present invention, the reactor further comprises a separator (14). A downstream leg (16) extends from the lower part of the separator (14) into the fluid conduction pipe (17).

In another embodiment of the present invention, the nozzles spray gas, preferably the gas components. Preferably, the slurry-bed reaction is a Fischer-Tropsch reaction.

In another aspect of the present invention, there is provided a method for conducting a slurry-bed reaction that uses a slurry-bed reactor comprising a reactor housing and the following components arranged on or in the reactor housing: an upper outlet, a fluid conduction pipe, a lower inlet and a slurry bed layer, and at least one nozzle is provided in said fluid conduction pipe with its opening pointing downward or obliquely downward, said method comprising: i) introducing gas components into the slurry-bed reactor through the lower inlet so that the gas components rise in an annular space between the exterior wall of the fluid conduction pipe and the interior wall of the reactor housing, driving the slurry of said slurry bed layer in the annular space to rise with the gas components, and the gas components reacting in the slurry; ii) at least a portion of the slurry of the slurry bed layer entering into the fluid conduction pipe through an upper opening of the fluid conduction pipe and flowing down along the fluid conduction pipe and flowing out at the lower outlet of the fluid conduction pipe to the annular space, and the at least one nozzle spraying gas, fluid or slurry into the annular space; iii) repeating steps (i) and (ii) above. Brief Description of the Drawings

Figure 1 shows a schematic diagram of the slurry-bed reactor according to one embodiment of the present invention. Figure 2 shows the longitudinal cross section of the fluid conduction pipe of the reactor shown in Figure 1.

Figure 3 shows the cross section of the fluid conduction pipe of the reactor shown in Figure 1.

Figure 4 shows a schematic diagram of the slurry-bed reactor according to another embodiment of the present invention.

Figure 5 shows the longitudinal cross section of the fluid conduction pipe of the reactor shown in Figure 4.

Figure 6 shows a schematic diagram of a separator and relevant components of the reactor of the present invention.

Figure 7 shows a structural schematic diagram of a gas distributor of the reactor of the present invention.

Figures 8(a)-8(d) show a distribution schematic diagram of the settings of the nozzles used in Examples 1-3.

Reference labels used in the drawings:

Extension section 24

Separating plate Short tubes

Tapered baffle 21

Downstream pipe 20

Nozzle 19-1 , 19-2 Flared opening 18

Fluid conduction pipe 17

Downstream leg 16

Separator outlet 15

Separator 14

Upper outlet 13

Lower inlet 12

Gas distributor 1 1

Material drawing outlet 10

Upper heat exchange tube inlet Middle heat exchange tube inlet Lower heat exchange tube inlet Upper heat exchange tube outlet Middle heat exchange tube outlet Lower heat exchange tube outlet Heat exchange tubes 4-1 4-2 4 Slurry bed layer 3

Housing 1

Examples The "range" disclosed herein is in the form of lower limit and upper limit. There can be one or more lower limits, and one or more upper limits, respectively. A given range is limited by selecting a lower limit and an upper limit. The selected lower limit and upper limit will determine the boundary of the specific range. The range limited by such way can be included or combined, i.e. any lower limit and any upper limit can be

combined to form a range. For example, the range of "60-120 and 80-110" that is given by specific parameters can be understood to be 60-110, 60-80, 80-120 and 110-120. In addition, if the minimum value is 1 and 2, and a maximum value is 3, 4, and 5, the following range can thus be expected: 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, 3-4, and 4-5. Unless otherwise specified, all of the embodiments and preferred embodiments described herein can be combined to obtain new technical solution.

Unless otherwise specified, all of the technical features and preferred features described herein can be combined to obtain new technical solution.

Unless otherwise specified, all of the steps described herein can be performed in order or randomly, preferably in order. For example, said method comprises steps (a) and (b) means said method can comprise steps (a) and (b) in such order, or steps (b) and (a) in such order. For example, said method further comprising step (c) means step (c) can be added into said method in any order, for example, said method may comprise steps such as steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b).

The method of the present invention can be used to implement a slurry-bed reaction which is a system that allows gaseous reactants to react with solid substances in a slurry of liquid materials. Although the reaction equipment and systems for implementing the method of the present invention will be discussed hereinafter in combination with the drawings, a person skilled in the art could understand that various alternations and modifications may be made to these reaction equipments and systems to adapt to the specific requirement without departing from the spirit and scope of the present invention. Figure 1 shows one embodiment of the slurry-bed reactor of the present invention. The reactor comprises housing 1 which comprises a separating plate 23, an extension section 24, a fluid conduction pipe 17, three-section heat exchange tubes 4-1, 4-2, 4-3 and gas distributor 1 1 which are placed sequentially from top to bottom in the housing 1. Slurry bed layer 3 containing liquid and solid material is located in the reactor. In the reaction process, the gas reactant is fed into the reactor from the inlet 12 at the lower end of the housing 1 and is distributed evenly through the gas distributor 11. Then it goes up through the slurry bed layer 3 as indicated by the upward arrows in the two sides of Figure 1. The reaction conditions such as temperature, pressure are selected according to the specific reaction type in order to conduct the reaction and produce the desired products. A separator 14 is provided above the slurry bed layer 3. The separator could be any known segregation means or segregation means that will be developed in the future which are suitable for the separation of the gas products and the slurry. For example, hydraulic cyclone could be used.

To improve the circulation of the slurry and gas materials and promote heat transfer in the reactor, at least one nozzle is provided in the fluid conduction pipe 17 with its opening directed downward or obliquely downward wherein the angle between said opening direction and the axial direction of the reactor is 0-90°, preferably 0-60° in the present invention. The "axial direction" described herein means the direction that go through the center line of the reactor, like the direction indicated by the downward arrows in Figure 1. As shown in Figure 2, four nozzles 12-1 are provided in said fluid conduction pipe 17 and through the wall of the fluid conduction pipe with its opening sloping downward and form an angle of 5^45° with the axial direction, preferably 10^40°, more preferably 15^35°, more preferably 20^33°, more preferably 25^30°. The nozzles are provided in a spiral form relative to the fluid conduction pipe 17. One nozzle is provided in each layer. From the top view in Figure 3, it can be seen that the four nozzles are evenly arranged along the circumference of the fluid conduction pipe. A person skilled in the art would recognize that any number of nozzles 19-1 could be provided in the fluid conduction pipe 17, and different number of nozzles could be provided in each layer (each horizontal height) according to the specific process requirements. Preferably, 1-8 nozzles are provided in each layer. More preferably, 1 -6 nozzles are provided in each layer. More preferably, 1 -4 nozzles are provided in each layer. More preferably, 1 -2 nozzles are provided in each layer. More preferably, one nozzle is provided in each layer. Thus, from the top view, the nozzles placed along the circumference of the fluid conduction pipe could be spaced evenly or unevenly to each other. Preferably each nozzle is placed evenly spaced along the circumference of the fluid conduction pipe. In the top view of the fluid conduction pipe, as shown in Figure 3, Figure 8(c) and Figure 8(d), the angle between the opening direction of the nozzles 19-1 and the fluid conduction pipe wall could be any appropriate direction, preferably 0-90°. The angle between the opening direction of the nozzles 19-1 and the fluid conduction pipe wall as described herein means the angel between the opening direction of the nozzles 19-1 and the circle tangent on the cross section of the fluid conduction pipe wall at the place. For example, Figure 8(c) shows 0° which means that the opening direction of the nozzles 19-1 is along the tangent of the inner wall of the fluid conduction pipe. However, in Figure 8 (d), the nozzles 19-1 extend from the fluid conduction pipe wall to the inner side and form a specific angle of 0-90° with the inner wall of the fluid conduction pipe.

In a preferred embodiment of the present invention, the nozzles 19-1 spray gas in the sloping downward direction in the fluid conduction pipe.

The gas could be any gas which does not have any negative effect on the reaction such as air, oxygen, nitrogen, noble gas or one or more components of the gas materials specifically used in the reaction. In a preferred

embodiment of the present invention, the gas sprayed from the nozzles is one or more components of the gas materials used in the reaction. In a preferred embodiment of the present invention, the reaction in the reactor is Fischer Tropsch reaction. The gas sprayed in the nozzles is mixture of raw gas materials.

In the slurry-bed reactor of the present invention, the nozzles 19-1 is connected with gas supply device to spray gas into the fluid conduction pipe. These gas supply devices could be any gas supply device known in the art. For simplicity, the gas supply device connected with these nozzles is not shown in the drawings.

Figure 4 shows another embodiment of the present invention. In this embodiment, the fluid conduction pipe 17 does not use the multiple nozzles layered along the inner wall in a spiral form, but uses the nozzles 19-2 with the shower-head shape which are arranged along the center line of the reactor. Said nozzles opening is placed along the axis and downward. The distance between the nozzles and the lower outlet of the fluid conduction pipe is 0-1 meter, more preferably 0.1-0.9 meter, more preferably 0.2-0.8 meter, more preferably 0.3-0.7 meter, more preferably 0.4-0.6 meter, more preferably 0.5 meter. The fan-shaped angle of the shower head-shaped opening is 10^90°, preferably 20^80°, more preferably 30^70°, more preferably 60°. The gas sprayed from said nozzles is the same as that in the nozzles of the device shown in Figure 1. The nozzles 19-2 are also connected with any gas supply device known in the art. The gas supply device connected with these nozzles is also not shown in the drawings.

In addition, the fluid conduction pipe 17 has been improved in the present invention. In particular, as shown in Figure 2, the fluid conduction pipe 17 comprises a flared opening 18, a downstream pipe 20, a tapered baffle 21 provided at the top, and multiple nozzles 19-1 provided in said

downstream pipe 20. Multilayer parallel circular projections are provided on the outer surface of the flared opening 18. The angle between the circular projections and the axial direction of the slurry-bed reactor is 30^80°, preferably 50^70°, most preferably 60°. In the reactor shown in Figure 1 , components such as separator 14, fluid conduction pipe 17, gas distributor 11 , gas inlet 12, gas outlet 13, separating plate 23 are all arranged relative to the center line of the reactor that is used as the center. A person skilled in the art could recognize that one or more of these components can be arranged to be deviating from the center line according to specific process requirements.

A tapered baffle 21 is provided at the lower part of the fluid conduction pipe 17. The tapered baffle has conical structure with its cusp upward and toward the opening of the lower part of the fluid conduction pipe 17.

The reactor in Figure 1 comprises three-section heat exchange tubes which comprise upper heat exchange tube 4-1, middle heat exchange tube 4-2 and lower heat exchange tube 4-3. In the reaction process, the heat exchange fluid flow through the inlets 5, 7 and 9 of the three heat exchange tubes, exchange heat with the materials in the reactor when passing through the heat exchange tube wall and flow out from the outlets 2, 6 and 8.

According to the exothermicity and endothermicity of the reaction process, cooling fluid or heating fluid can be used in the heat exchange tubes to transfer the heat from the reaction system or heat the reaction system. Any heat exchange fluid known in the art could be used, like air, water, oil, alcohol and so on. This embodiment employs a three-section heat exchange tubes. It can be seen that the heat exchange tubes from bottom to top are gradually thicker and the number of the tubes gradually decrease, which means the overall heat transfer capacity of the heat exchange tubes decrease gradually from bottom to top. Considering the gas reactant is supplied to the gas inlet 12 at the reactor bottom, the concentration of the gas reactant is higher and the reaction is more powerful at the bottom. When going up, the gas reactant is gradually reacted and consumed, which makes the gas reactant concentration decrease and the exothermic or endothermic effect of the reaction is uneven in the longitudinal direction. Therefore the distribution density of the heat exchange tubes is reduced progressively from bottom to top to ensure the bulk temperature to be stable at different height in the reactor.

The gas distributor 11 comprises a number of short tubes 22 thereon, as shown in Figure 7. These short tubes are arranged along different concentric circles in loop-ribbon form. As shown in Figure 7, openings in horizontal direction are provided above the distributor disk plane in which the short tubes are located. Such design could effectively prevent the openings from being blocked by the catalyst sediment. Figure 7 shows that the openings of the short tubes are in a direction perpendicular to the axial direction. They can also open in vergence direction sloping downward. For example, the angle with the axial direction could be 45°-90°, preferably 45° or 90°.

The separator 14 is provided above the fluid conduction pipe 17. The separator 14 comprises separator outlet 15 and downstream leg 16, wherein the separator outlet 15 is provided above the separating plate 23 while the body of the separator 14 and downstream leg 16 are located below the separating plate 23. The downstream leg extends downwardly into the fluid level of the slurry bed layer 3 and extends into the flared opening 18 of the fluid conduction pipe 17 so that the fluid separated from the gas-liquid separator can be introduced directly into the fluid conduction pipe with greater density to promote the fluid circulation inside and outside of the fluid conduction pipe. In this embodiment of the present invention, the separator is preferably hydraulic cyclone. The gas flow rate at the tangent inlet of the hydraulic cyclone is 10-30 m/s.

A material drawing outlet 10 is provided among the three-layer heat exchange tubes in the middle of the reactor to draw the liquid products, byproducts, intermediate products or inactivation catalyst formed in the slurry bed layer during the reaction. For example, when the reactor of Figure 1 is used for Fischer Tropsch reaction, the synthetic oil- wax precuts can be drawn out of the slurry through the material drawing outlet 10.

The height of the top end of the fluid conduction pipe is close to that of the fluid level of the slurry bed layer, and is submerged below the fluid level of the slurry bed. In an embodiment of the present invention, the upper edge of the flared opening is located in depth of 0.1-1 meter below the fluid level of the slurry bed layer, preferably 0.1-0.9 meter below, preferably 0.1-0.8 meter below, preferably 0.1-0.7 meter below, preferably 0.1-0.6 meter below, preferably 0.1-0.5 meter below. Take the reactor of Figure 1 as an example. The reactor of the present invention is operated as indicated below: before reaction, the slurry is placed in the reactor to form slurry bed layer. The fluid level of the slurry bed layer is made to cover the top surface of the flared opening of the fluid conduction pipe. The reactor is provided with appropriate reaction condition. The gas reactant is fed through the lower inlet of the reactor. The fluid conduction pipe is submerged under the material level of the slurry bed. When the gas reactant is sprayed through the gas distributor and flow upwardly, it drives the bed layer slurry outside of the fluid conduction pipe to flow upwardly and forms the gas-liquid-solid three-phase slurry bed layer which flows upwardly. When the gas-liquid-solid three-phase fluid gets to the flared opening height, the gas keeps flowing upwardly due to its smaller density and greater buoyancy until it departs from the fluid level of the slurry bed layer.

Meanwhile, the liquid and catalyst flow into the flared opening due to greater density, then flow down the fluid conduction pipe and flow out from the lower outlet of the fluid conduction pipe. The liquid and catalyst finally flow back into the space outside of the fluid conduction pipe and again flow upwardly under the force of the gas reactant from the gas distributor. A tapered baffle is provided under the fluid conduction pipe to effectively prevent the gas reactant from the gas distributor from directly flowing into the fluid conduction pipe through the lower outlet of the fluid conduction pipe. That results in the circulation fluid flow inside and outside of the fluid conduction pipe. The circulating liquid and catalyst becomes the

supplementary fluid for the reactor indirectly. However, the space occupied by the fluid conduction pipe in the reactor is much smaller than the fluid circulation volume formed outside of the fluid conduction pipe. If the circulation described above only depends on the density difference without using the nozzles, the result will not be satisfied. For this reason, multiple gas nozzles spraying gas in the direction of sloping downward are provided in the fluid conduction pipe by the inventor. The gas materials delivered by the gas supply device are sprayed into the fluid conduction pipe through the gas nozzles and provide downward force for the slurry in the fluid conduction pipe, thereby producing better circulation effect in the entire reactor. On the other hand, a flared opening is provided at the upper end of the fluid conduction pipe, and multilayer parallel circular projections are provided on the outer surface of the flared opening by the applicant. When the slurry tumbles into the flared opening of the fluid conduction pipe as described above, the flared opening of the structure could facilitate the gas-liquid separation, reduce bubbles entrained in the slurry tumbling into the fluid conduction pipe, and further reduce the resistance of the bubble entrained into the fluid conduction pipe to the slurry circulation. In addition, to prevent the gas materials from the gas distributor from directly getting into the fluid conduction pipe through the lower outlet of the fluid conduction pipe when the gas materials go up, a tapered baffle is provided under the fluid

conduction pipe outlet to effectively prevent the gas materials from directly getting into the fluid conduction pipe through the bottom opening of the fluid conduction pipe. The inventors find that if the gas materials get into the fluid conduction pipe directly through the bottom opening of the fluid conduction pipe, it will bring resistance to the reactor circulation and the space utilization efficiency of the reactor will be reduced. Said tapered baffle will realize smooth slurry circulation in the reactor.

In the reactor shown in Figure 4, a nozzle of shower-head shape with its opening pointing downward is provided along the axis in the fluid conduction pipe 17 by the inventor. The working principle and effect is similar to the nozzle of Figure 1. That also facilitates the circulation flow of the slurry inside and outside of the fluid conduction pipe in the direction as shown by the arrows in the figures.

It can be seen that the fluid conduction pipe system has been improved comprehensively by the inventor. The flared opening provided on the top with multilayer parallel circular projections on its out surface and the tapered baffle under the fluid conduction pipe are used to eliminate the resistance of the bubble that is inappropriately entrained in the fluid conduction pipe. The nozzles spraying gas downwardly are used to provide additional driving force for downward flow. The combination of flared opening, the tapered baffle and the nozzles could significantly increase the slurry flow in the fluid conduction pipe and promote the circulation efficiency in the reactor.

In addition, the gas distributors in the prior arts usually open upwardly, which makes the openings be easy to be blocked by the solid catalyst sediment and other components. The applicant made further improvement to the gas distributor. As aforementioned by referring to Figure 7, the gas distributor of the present invention comprises a number of short tubes distributed in ring structure. These short tubes spray gas in side direction or sloping downward direction. The advantage of the technical solution is that the short-tube high-rate gas nozzles facilitate the gas-liquid-solid three-phase mixing in the reactor, and the side opening could prevent the opening being blocked by catalyst particles falling into the opening. In addition, the loop-ribbon distributor can effectively distribute the gas reactant to the reaction zone.

Therefore, compared with the prior arts, the technical effect of the invention is:

1. Gas nozzles are provided in the fluid conduction pipe to spray gas in the direction of downward or sloping downward. Meanwhile, the flared opening provided on the top with multilayer parallel circular projections on its out surface facilitates the gas-liquid separation. The tapered baffle at the outlet also facilitates the fluid circulation and increases the airspeed and space utilization efficiency in the reactor and reduces the reactor investment.

2. For the gas distributor with the short tubes distributed evenly in loop-ribbon form, the issue of block by the catalyst is resolved by the side opening of the short tubes. That keeps the gas distributor have the high gas flow rate all the time during the reaction, and guarantee the uniform mixing of the gas and slurry in the circulating reactor.

3. In addition, aforementioned structure design could facilitate the slurry circulation inside and outside of the fluid conduction pipe. The catalyst at the top of the slurry bed layer can be recycled to the bottom of the reactor and avoid the inactivation of the catalyst due to staying in the oxidation condition at the top of the slurry bed layer. The nozzles in the fluid conduction pipe provide a part of the raw gas reactant, which further guarantees the catalyst being in the conditions that is hard for oxidation, and improve the reaction microenvironment for catalyst, thereby improving the catalyst stability. The reactor of the present invention can be used for any gas-liquid-solid three-phase slurry-bed reaction. For example, in a preferred embodiment of the present invention, the reactor is used for Fischer- Tropsch reaction. The synthesis gas comprising carbon monoxide and hydrogen is used as raw material. The slurry bed layer is formed by suspending the solid catalyst in inert liquid solvent. The synthesis gas flow goes through said slurry outside of the fluid conduction pipe under appropriate reaction condition. During ascending with the slurry materials in the reactor, the gas reacts to produce hydrocarbon including wax and hydrocarbon oil and releases large quantity of heat. The heat generated in the reaction is removed by heat exchange effect of the upper, middle and lower three-section heat exchange tubes in the reactor. In particular, in an embodiment, the cooling water is fed into the upper heat exchange tube inlet 5, middle heat exchange tube inlet 7 and lower heat exchange tube inlet 9, and then exchanges heat with the slurry bed layer through the wall of heat exchange tubes 4-1, 4-2, 4-3, and finally flows out from the upper heat exchange tube outlet 2, middle heat exchange tube outlet 6 and lower heat exchange tube outlet 8. Material drawing outlet 10 is provided at the position among said three-section heat exchange tubes to draw out the wax and hydrocarbon oil produced in the bed layer. The amount of the drawn wax and hydrocarbon oil products is controlled. It should be noted to supplement the inert solvent all the time to maintain the slurry-bed fluid level to be higher than the top of the fluid conduction pipe within a proper range.

When the synthesis gas rises to the fluid level of the slurry bed layer and overflows from the fluid level, small amount of liquid product wax or synthetic oil, solvent and solid catalyst are entrained in the synthesis gas. The tail gas goes up into the separator 14, i.e. hydraulic cyclone in this preferred embodiment. The synthesis gas in the tail gas is separated from the wax, synthetic oil liquid, solvent and solid catalyst in the hydraulic cyclone. The purified gas is expelled from the hydraulic cyclone outlet 15 while the separated liquid and catalyst flow down the downstream leg 16 into the fluid conduction pipe 17 to facilitate the fluid circulation inside and outside of the fluid conduction pipe 17.

Hydraulic cyclone outlet 15 extends to the part above the separating plate 23. The purified gas where the liquid and catalyst have been removed is expelled at the part above the separating plate through the reactor upper outlet 13.

The detailed operation of the reactor of the present invention will be specifically set forth in the following examples by taking Fischer-Tropsch reaction as an example. However, it should be understood that the reactor of the present invention and the method of use thereof can be used to any other similar three-phase slurry-bed reaction, for example, the synthesis of dimethyl ether by a one-step method using synthesis gas, the synthesis of methanol using three-phase slurry-bed or other process. The following examples are used to illustrate the invention specifically, and not to limit the scope of the invention.

Examples

Example 1

The reactor of Figure 1 is used in this example for Fischer- Tropsch reaction. The inner diameter of the slurry-bed stainless steel reactor housing is 1.2 meters. The axial height of the reactor is 35 meters. One fluid conduction pipe is provided in the reactor. One hydraulic cyclone is provided at the top of the reactor. The fluid level of the slurry bed is 18 meters above the synthesis gas distributor. The upper edge of the flared opening at the top of the fluid conduction pipe is 14.5 meters above the synthesis gas distributor. The bottom of the downstream pipe of the fluid conduction pipe is 0.2 meter above the synthesis gas distributor. The inner diameter of the downstream pipe 20 of the fluid conduction pipe 17 is 0.36 meter. The fluid conduction pipe is completely submerged under the fluid level of the slurry bed layer. The outer surface of the flared opening at the upper end of the fluid conduction pipe 17 comprises 6 rows of circular projections. The height of the circular projections is 0.25 meter. The angle between the circular projections and the axial direction is 60°. The downstream pipe of the fluid conduction pipe is provided with 8 nozzles arranged in spiral form with their opening sloping downward. The diameter of the nozzles is 0.02 meter. These nozzles are connected with the synthesis gas supply device (not shown in the drawings). The synthesis gas is sprayed at the rate of 10 m/s by each nozzle. As shown in Figure 8(a), the angle between the nozzles and the axial direction is 30°. The nozzles go through the wall of the fluid conduction pipe 17. 8 nozzles are arranged in different layers with one nozzle in each layer. The nozzles are arranged from top to bottom, starting from 1 meter below the flared section of the sedimentation tubes. The vertical interval between each layer is 1 meter. As shown in the top view of Figure 8(c), the nozzles of neighboring layer are arranged evenly along the circumference of the fluid conduction pipe with its opening along the tangential direction of the fluid conduction pipe wall in horizontal orientation. A spiral downward suction is formed in the slurry in the fluid conduction pipe through the spiral gas spray, which thereby produces better circulation effect. It can be seen from Table 2, after the nozzles are opened and spray gas, the fluid flow rate in the fluid conduction pipe is increased by 83% compared with the situation that the nozzles are not opened. In addition, a tapered baffle is provided under the fluid conduction pipe bottom to prevent the synthesis gas from getting into the fluid conduction pipe through the fluid conduction pipe bottom when the gas goes up, and to ensure the smooth circulation of the slurry in the reactor.

The hydraulic cyclone is located at the top of the reactor. In the hydraulic cyclone, the unreacted synthesis gas and the light hydrocarbon gas obtained as the by-product are separated from the liquid and catalyst entrained in the gas. Then the gas flows out from the hydraulic cyclone outlet to the upper space of the separating plate and finally flows out from the upper outlet of the reactor while the separated liquid and catalyst flow down the

downstream leg into the fluid conduction pipe. That facilitates the

circulation inside and outside of the fluid conduction pipe, too. The resulted product wax and hydrocarbon oil of the reaction is drawn out from the material drawing outlet 10 in the middle of the reactor. The amount to be drawn out could be adjusted to change the height of the slurry bed layer if necessary. In this example, Table 1 shows the temperature and pressure in the reactor, the composition and superficial gas rate of the synthesis gas supplied to the lower end of the reactor. Synthesis gas materials of same

compositions are supplied to the fluid conduction pipe through the nozzles. Saxoline is used as solvent which is a hydrocarbon mixture of 18-30 carbon, wherein the main component is linear-chain alkanes (about 80%~95%).

Small amount of branched-chain alkanes and monocyclic cycloalkanes with long side chain (less than 20%, together) are also included. Cobalt-based catalyst that is commonly used in Fischer-Tropsch reaction is used. The mass ratio of the catalyst in the slurry is 15%. More description about the slurry used in the present invention can be found in Jie Chang, et al. Chin J Catal, 26(10), 859-868, 2005.

The synthesis gas materials are supplied into the reactor through the synthesis gas inlet at the reactor bottom. After being distributed through the side opening of the short tubes on the gas distributor, the synthesis gas rises in the reaction zone between the fluid conduction pipe and the reactor wall. As Fischer-Tropsch reaction is strong exothermic reaction, the three-section heat exchange tubes are needed to remove the heat timely, and maintain the temperature of the slurry bed layer at the preset temperature shown in Table 1. For this purpose, cooling water is supplied in the heat exchange tubes. The water volume and temperature are controlled. The preferred temperature of the supply water is 180^200 ^° C . In the reaction zone, gas-liquid-solid three-phase mixture is formed by the synthesis gas, synthetic wax and hydrocarbon oil, and catalyst in the slurry bed. The Fischer-Tropsch synthetic reaction occurs in the synthesis gas in the presence of catalyst and produces wax and hydrocarbon oil and a small part of light hydrocarbon as by-product. The products are characterized and analyzed by Shimadzu GC-14C Gas Chromato graph System. Specific components and the contents are obtained and shown in Table 1.

The inventors of the present invention use the slurry-bed reactor of Example 1 for the Fischer-Tropsch reaction, and use the gas chromatography to detect the CO concentration at the upper outlet. The CO conversion ratio is calculated to evaluate the efficiency of the reactor. The reaction is also performed under the same reaction condition when the nozzles in the fluid conduction pipe are not open. CO conversion ratio is calculated and used as the control. In addition, the flow rate detector is provided in the fluid conduction pipe to monitor the downward flow rate of the slurry during the reaction.

Furthermore, the inventors continue to use the Fischer-Tropsch reaction and adjust the refresh rate of the catalyst according to the gas chromatography detection results of the product CO. In particular, when the CO conversion ratio drops to 80% of the initial value, the catalyst is removed from the reaction system and the fresh catalyst is added until the CO conversion ratio rises to more than 95% of the initial value. The aforementioned operation is repeated over the time. When the amount of the newly added catalyst is equal to that of the initial catalyst, 100% of the catalyst is considered to be replaced. The hour at this time is recorded as the catalyst life. The aforementioned results are shown in Table 2.

Example 2: the same reaction equipment as that of Example 1 is used in the example, except that, as shown in Figure8 (b), the arrangement of the nozzles in the fluid conduction pipe is changed as follows: 8 nozzles are arranged to two layers with 4 nozzles for each layer. The vertical interval between each layer is 4 meters. The nozzles are provided at 4 meters and 8 meters under the flared section of the fluid conduction pipe. These nozzles are arranged evenly along the circumference of the fluid conduction pipe. The angle between each nozzle and the axial direction is 30°. The arrangement in horizontal orientation of the nozzles is the same as Figure 8 (c) where the opening direction of the nozzles is along the tangential direction of the fluid conduction pipe wall. The experiment results are shown in Table 2. Example 3: The arrangement of the reactor is the same as that in

Example 1 except that, in the top view, nozzles are arranged as shown in Figure 8 (d), wherein the opening of the nozzles is closer to the middle of the fluid conduction pipe and the angle between the opening direction and the tangential direction of the place where the nozzles get through the fluid conduction pipe wall is about 60°. The arrangement can avoid the reactor wall's blocking to the sprayed gas. The experiment results are shown in Table 2.

Example 4: The arrangement of nozzles on the fluid conduction pipe 17 is changed while the other devices of the reactor remain the same. Nozzles 19-2 with the shower-head shape as shown in Figure 5 are used. The nozzles are provided with the opening pointing downwardly along the axial direction and are 0.5 meter away from the lower outlet of the fluid conduction pipe. The fan-shaped angle of the opening with the shower-head shape is 60°. The diameter of the nozzle is 0.02 meter. The nozzles are connected with the outer synthesis gas supply device. The synthesis gas supplied is the same as the synthesis gas introduced in the reactor lower inlet. The synthesis gas flow rate is 10 m/s. The experiment results are shown in Table 2. Table 1. Reaction condition of the bubble slurry-bed reactor for the Fischer-Tropsch reaction and hydrocarbon compositions of the product

Reactor diameter/m 1.2

Reaction pressure/MPa 2.0

Reaction temperature/ ^° C 220

Lower inlet gas

1628 flow/m 3 ^e h ^" 1

Operating condition Lower inlet superficial gas

0.4

flow/ m ^e s ^_1

H ₂ Volume ratio 0.653

Feed gas

CO Volume ratio 0.327 composition

N ₂ Volume ratio 0.02

selectivity to CH ₄ /% 6.2

Hydrocarbon product

selectivity to C _2-4 /% 7.2

composition

selectivity to C _5-9 /% 12.7

(molar)

selectivity to Ci _0-2 o/% 31.4

selectivity to C ₂ i _-40 /% 34.7

selectivity to C ₄₀₊ /% 7.8

Table 2. Test results of the Fischer-Tropsch reaction with various slurry-bed reactors

It can be seen from Table 2 that nozzles used in the fluid conduction pipe increase the flow rate of the slurry in the fluid conduction pipe. Accordingly, CO conversion ratio is increased significantly. This shows that the slurry-bed reactor of the present invention could generate much smoother material circulation, thereby promoting the reaction efficiency. In addition, since the circulation efficiency inside and outside of the fluid conduction pipe has been increased, the catalyst particles rising to the place near the slurry fluid level outside of the fluid conduction pipe could be recycled to the place near the reactor bottom, which effectively inhibited accumulation of the catalyst near the top fluid level of the slurry where the catalyst is inactivated under oxidation condition. The catalyst life is thus prolonged.

For the reactors with different structures in Examples 1 -4, the reactor of Example 3 has obtained the best intra-pipe flow rate and CO conversion ratio. Unlike Example 1 and 2, the nozzles of Example 3 are not arranged along the tangential direction of the inner wall of the fluid conduction pipe, which effectively reduce the resistance of the inner wall of the fluid conduction pipe to the gas sprayed from the nozzles. The reactor of Example 3 makes full use of the gas flow sprayed from the nozzles to promote the material circulation in the reactor. Example 4 has the smallest progress in promoting the intra-pipe flow rate and CO conversion ratio according to the contrast experiment. However, it also has significant improvement and shows its value in industrial application.