Field of the Invention

The present invention relates to the field of chemical industrial equipment and chemical industry. In particular, it relates to an inner-circulating three-phase bubble column slurry-bed reactor and a method of use thereof.

Background

Slurry-bed reactors are widely used in chemical industrial manufacturing, such as oxidation process, Fischer-Tropsch synthesis, biological fermentation, waste-water treatment and so on due to their simple construction, that they are considered easy to manufacture and amplify, and low cost in operating and maintenance. Slurry-bed reactors of variant design have been reported in literature and patents. For example, Chinese patent CN1137769C describes a slurry-bed synthetic reaction equipment comprising an ascending pipe, a descending pipe, a gas distributor and stirrer. Chinese patent CN1233451 C describes a gas-liquid- solid three-phase slurry-bed industrial reactor for continuous operation. Chinese patent application CN1593740A describes a high performance slurry-bed reactor consisted of inner sleeve with variable diameter, block-preventing nozzles, secondary distributor and so on.

Chinese patent CN100443155C provides a slurry-bed circulating reactor with high separation efficiency and simple construction. Chinese patent

CN 100512941C discloses a slurry-bed reactor equipment with internal gas circulation. Chinese patent CN101396647B provides a gas-liquid-solid three-phase suspended bed reactor for Fischer-Tropsch synthesis. Chinese patent CN201052457Y provides a new inner-circulating slurry-bed reactor. The internal circulation of the slurry is realized through the risers consisted of heat exchange tubes. Chinese patents CN101417220B and CN101480595B each provides a slurry-bed reactor with tube array improved through

arranging multi-horizontal grid resistance internals and tube bundles with needle type pin, respectively. Chinese patent CN 102188938 A provides an inner-circulating slurry slurry-bed reactor for Fischer-Tropsch synthesis through disposing a group of circulation cuvette. Chinese patent

CN102416307A provides an inner-circulating slurry-bed reactor comprising multiple internal cylinders. PCT Patent application No. WO 1994015160 provides an inner-circulating slurry-bed reactor which strengthens the separation of gas and liquid.

Gas/liquid/solid mixing and interphase mass transfer of the slurry-bed reactor known in the art is improved mainly by mechanical stirring, gas distributor and redistributor and descending pipe of loop reactor. The commonly used gas distributor and descending pipe in the loop reactor has been found to have little effect in improving the mixing and interphase mass transfer. The slurry in reactors such as loop reactor is found to be slow and this is thought to be due to the internal circulation formed by density difference, thus the velocity of the operating gas should preferably not be too high so as to avoid relative high speed between gas and liquid which will in some cases might result in disadvantageous back-mixing. The mechanical stirring is considered to be unsuitable for high pressure applications, for example in view of the needs for shaft seal and other reasons.

In examples of a slurry-bed reactor, gas is distributed in the slurry through bubbling. Gas-liquid mass transfer and chemical reaction thus can take place substantially simultaneously in ascending process of the gas and the slurry. The interphase mass transfer efficiency is considered to play a critical role in the reaction process (Jue Wang et al. Chemical reaction engineering and technology 23 (6), 499-504, 2007). The space-time yield is thought also to be limited directly by the low operating gas speed. How to improve interphase mixing and distribution effect, facilitating the mass transfer process, increasing catalyst utilization ratio while decreasing the back-mixing in the slurry-bed are key in the realization of a high performance slurry-bed reactor. There is a need for a slurry-bed reactor to meet such requirements.

A new reactor and a method of use thereof are developed in the present invention. The reactor and the reactor described in CN 201052457Y both use the slurry inner-circulating method, wherein the center cylinder is used as reaction zone and diversion cylinder. Veturi effect and sedimentation tubes of the present invention are used to strengthen the mixing and mass transfer process and increase the reaction efficiency. Periphery sedimentation tubes and low pressure syphoning effect are also used to improve the inner circulation of the slurry, reduce the back-mixing and increase the space-time yield of the reactor.

In addition, the diversion cylinder of reactor described in CN 201052457 Y is comprised of heat exchange coiler and is easy to be limited by the amount of the heat exchange. The reaction zone vessel and sedimentation tubes of the present invention are separated from the heat exchange tube bundles to improve the operability of the reactor.

Summary of the Invention

The present invention provides a new high performance slurry-bed reactor. In some embodiments, the slurry-bed reactor can facilitate the mixing and mass transfer process, promoting the reaction process, enhancing the reactor efficiency and overcoming the aforementioned disadvantages of prior arrangements by improving the lower gas inlet assembly. According to an aspect of the invention, there is provided a slurry-bed reactor comprises a reactor housing 1 , and the following components arranged within or on the reactor housing (1): a lower gas inlet assembly, a reaction zone vessel (6), a sedimentation tube (5) and an upper outlet (14), wherein the upper part of the reaction zone vessel (6) and the upper part of the sedimentation tube (5) open up towards the same chamber in the reactor housing and are in fluid communication with said chamber. The upper outlet (14) can be used for discharging gas from said chamber, wherein said lower gas inlet assembly is a Venturi equipment. The outlet of the lower gas inlet assembly is in fluid communication with the lower part of the reaction zone vessel (6) and the lower end of the sedimentation tube (5) is in fluid communication with the flank of the lower gas inlet assembly. The inside of the reactor house is configured to allow a slurry to pass through the reaction zone vessel (6), the sedimentation tube (5), the lower gas inlet assembly and the reaction zone vessel (6) sequentially to form a flow cycle. In an embodiment of the present invention, the reactor further comprises a liquid outlet (8). The liquid outlet (8) can be used for discharging liquid from the chamber. The lower gas inlet assembly comprises a gas inlet tube (15), a narrowing portion (21), and a throat tube (16) that are connected in such order. The lower gas inlet assembly is connected and in fluid communication with the sedimentation tube (5) through the throat tube (16) or the narrowing portion (21). In some embodiments of the present invention, the lower gas inlet assembly comprises a gas inlet tube leading to a narrowing portion leading to a throat tube, which is in fluid communication with the lower part of the reaction zone vessel with the lower gas inlet assembly located beneath the reaction zone vessel.

In an embodiment of the present invention, the lower end of the reaction zone vessel (6) is provided with a vessel flared opening (22) and a fluid aspirator (19), the fluid aspirator (19) has a downward flared opening. Preferably, a mixer tube 20 is provided between the vessel flared opening (22) and the fluid aspirator (19). Preferably, the lower end of the reaction zone vessel (6) is provided with a distributor (23). In an embodiment of the present invention, the upper end outlet of the throat tube (16) is placed in the reaction zone vessel (6), preferably in the mixer tube (20).

In an embodiment of the present invention, the reactor comprises one or more sedimentation tubes (5). Each sedimentation tube (5) includes a sedimentation tube flared opening (24), a feeding pipe (25) and a pipette (18). The joining portion between the feeding pipe (25) and the pipette (18) has an involute shape. More preferably, the one or more sedimentation tubes (5) are arranged around the axis of the reactor along the axial direction of the reactor. In another embodiment of the present invention, the reactor comprises n sedimentation tubes (5) and n is an integer of 2 to 20. The pipette (18) of each sedimentation tube (5) is connected and in fluid communication with the throat tube (16) of the gas inlet assembly. The diameter di of the pipette (18) is less than 1/n of the circumference of the throat tube ( 16) ' s cross section perpendicular to the vertical axis of the reactor. Preferably, the diameter di is preferably less than l/2n of the circumference of the throat tube (16)'s cross section perpendicular to the vertical axis of the reactor.

In another embodiment of the present invention, the reactor comprises n sedimentation tubes (5) and n is an integer of 2 to 20. The pipette (18) of each sedimentation tube (5) is connected and in fluid communication with the throat tube (16) of the gas inlet assembly. In another embodiment of the present invention, the sedimentation tube's flared opening (24) has an eccentric funnel shape. The ratio of the radius of the upper fluid material inlet (26) to the radius of the reactor housing (1) is 0.1-1, more preferably 0.5-1, most preferably 0.6-1. In another embodiment of the present invention, the lower end (27) of the sedimentation tube flared opening (24) is higher than the top end of the reaction zone vessel (6).

In another preferred embodiment of the present invention, the ratio of the diameter of the reaction zone vessel (6) to that of the reactor housing (1) is 0.7-0.97, preferably 0.95. The ratio of the height of the reaction zone vessel (6) to that of the entire reactor housing (1) is 0.5-0.9, preferably 0.6.

In another preferred embodiment of the present invention, the reactor further comprises heat exchange tube bundles (4), which comprise one or more heat exchange tubes. Preferably, each of the heat exchange tube has a cannular structure and is comprised of an outer tube (28) and an inner tube (29).

In another preferred embodiment of the present invention, a separating plate (12) and one or more segregation means (1 1) are placed in the upper part of the reactor. The segregation means (1 1) is consisted of a separator (30), a downstream pipe (31) and a downstream pipe outlet (32), wherein the downstream pipe (31) extends along the inner wall of the reactor housing (1). The downstream pipe outlet (32) is horizontally oriented towards the inner wall of the reactor housing (1).

In another preferred embodiment of the present invention, the reactor further comprises a slurry, and the upper end of the sedimentation tube (5) is submerged under the surface level of the slurry (3). Preferably, the ratio of the height of the surface level (3) of the slurry in the reactor to that of the reactor housing (1) is 0.5^0.9, preferably 0.7.

According to another aspect of the present invention, there is provided a circulation assembly for facilitating slurry circulation in a slurry-bed reactor, wherein the circulation assembly comprises a sedimentation tube and a gas inlet assembly. The gas inlet assembly comprises a gas inlet tube (15), a narrowing portion (21), a throat tube (16) that are connected in order. The gas inlet assembly is in fluid communication with the sedimentation tube.

In an embodiment of the present invention, the sedimentation tube includes a sedimentation tube flared opening (24), a feeding pipe (25) and a pipette (18) that are connected in order. Preferably, the joining portion between the feeding pipe (25) and the pipette (18) has an involute shape.

In another preferred embodiment of the present invention, the gas inlet assembly is connected and in fluid communication with the sedimentation tube through the throat tube (16) and the pipette (18). In another preferred embodiment of the present invention, the circulation assembly further comprises a reaction zone vessel (6). The lower end of the reaction zone vessel (6) has a vessel flared opening (22), a mixer tube (20) and a fluid aspirator (19). The fluid aspirator (19) has a downward flared opening. In another preferred embodiment of the present invention, the upper end outlet of the throat tube (16) is placed in the reaction zone vessel (6), preferably in the mixer tube (20).

According to another aspect of the present invention, there is provided a slurry-bed reactor, comprising: a reactor housing, and the following components arranged within or on the reactor housing: a lower gas inlet assembly, a reaction zone vessel, a sedimentation tube and an upper outlet, wherein the reaction zone vessel and the sedimentation tube each has an opening in its upper part and the two openings are in fluid communication with each other; wherein the lower gas inlet assembly comprises a gas inlet tube, a narrowing portion, a throat tube that are connected in order, wherein the throat tube is in fluid communication with the lower part of the reaction zone vessel, and the lower gas inlet assembly is located beneath the reaction zone vessel; and wherein the lower part of the sedimentation tube is in fluid communication with the lower gas inlet assembly in or near the region of the throat tube. The present invention also provides a novel method for conducting slurry-bed reaction, which can facilitate the mixing and mass transfer process, promote the reaction process, enhance the reactor efficiency and overcome aforementioned defects in the prior art by improving the lower gas inlet assembly and the operation process. The method uses a slurry-bed reactor comprising a reactor housing (1) and the following components provided in the reactor housing (1): a lower gas inlet assembly, a reaction zone vessel (6), a sedimentation tube (5), an upper outlet (14) and slurry, wherein said lower gas inlet assembly is a Venturi equipment in fluid communication with pipettes (18) at the lower part of the sedimentation tube (5). Said method comprises i) introducing gas components into said lower gas inlet assembly, when the gas components flow through the connection between the pipettes (18) and the lower gas assembly, the gas components are mixed with a slurry from the sedimentation tube (5) by the Venturi effect, the mixture of the gas components and the slurry entering into the reaction zone vessel (6) and rising inside the reaction zone vessel (6), the gas components reacting in the mixture; ii) the resulting gas products of the gas components reaction and the unreacted gas components rising and departing from the surface level (3) of the slurry, and being then expelled from the upper outlet (14), and at the same time a part of the slurry entering into the sedimentation tube (5) from the upper opening of the sedimentation tube and descending along the sedimentation tube, passing through the pipette (18) and being mixed with the gas components from the lower gas inlet assembly and being introduced into the reaction zone vessel (6) with the gas components; iii) repeating steps (i) and (ii).

In an embodiment of the present invention, the lower gas inlet assembly comprises a gas inlet tube (15), a narrowing portion (21) and a throat tube (16) sequentially connected in such order, and the lower gas inlet assembly is in fluid communication with the pipette (18) at said throat tube (16).

In another embodiment of the present invention, the lower end of the reaction zone vessel (6) is provided with a vessel flared opening (22), a mixer tube (20) and a fluid aspirator (19) sequentially connected in such order.

In another embodiment of the present invention, the reactor comprises n pieces of sedimentation tubes (5), n is an integral number between 2 to 20, the sedimentation tubes (5) are placed around the central axis of the reactor along the axial direction of the reactor, wherein each sedimentation tube (5) includes a sedimentation tube flared opening (24), a feeding pipe (25) and a pipette(18) sequentially connected in such order, the diameter di of the pipette (18) is less than 1/n of the circumference of the throat tube (16)'s cross section perpendicular to the vertical axis of the reactor, the diameter di is preferably less than l/2n of the circumference of the throat tube (16)'s cross section perpendicular to the vertical axis of the reactor, the feeding pipe (25) and the pipette (18) is connected at the part with an involute shape.

In another embodiment of the present invention, the sedimentation tube flared opening (24) has an eccentric funnel shape, the ratio of the diameter of the material fluid inlet upper end to the radius of the reactor housing (1) is 0.1-1, more preferably 0.5-1, most preferably 0.6-1.

In another embodiment of the present invention, the upper end of the sedimentation tubes (5) are submerged under the surface level of the slurry (3), the height of the upper end of the reaction zone vessel (6) is lower than that of the lower outlet (27) of the sedimentation tube flared opening (24).

In another embodiment of the present invention, the ratio of the diameter of the reaction zone vessel (6) to that of the reactor housing (1) is 0.7-0.97, preferably 0.95, the ratio of the height of the reaction zone vessel (6) to that of the entire reactor housing (1) is 0.5-0.9, preferably 0.6.

In another embodiment of the present invention, the ratio of the height of the surface level (3) of the slurry in the reactor to that of the reactor housing (1) is 0.5—0.9, preferably 0.7.

In another embodiment of the present invention, the reactor comprises heat exchange tube bundles (4) placed inside the reactor housing (1), which comprises a number of heat exchange tubes, each of which has a cannular structure and is comprised of an outer tube (28) and an inner tube (29). In another embodiment of the present invention, the top of the reactor is provided with 1-10 segregation means (1 1), the segregation means (1 1) is comprised of a separator (30), a downstream pipe (31) and a downstream pipe outlet (32) sequentially connected in such order, wherein the downstream pipe (31) extends along the inner wall of the reactor housing (1), the downstream pipe outlet (32) is horizontally oriented towards the inner wall of the reactor housing (1), when the gas components in step ii) pass through the segregation means (1 1), the slurry carried in the gas components is separated by the segregation means (1 1) and returns back below the surface level of the slurry (3) through the downstream pipe (31) and downstream pipe outlet (32).

In another embodiment of the present invention, the slurry-bed reaction is a Fischer- Tropsch reaction.

In another aspect of the present invention, there is provided a method for conducting slurry-bed reaction that uses a slurry-bed reactor comprising a reactor housing and the following components arranged within or on the reactor housing: a lower gas inlet assembly, a reaction zone vessel, a sedimentation tube, an upper outlet and slurry, wherein said lower gas inlet assembly comprises a gas inlet tube leading to a narrowing portion leading to a throat tube which is in fluid communication with the lower part of the sedimentation tube, said method comprises:

i) introducing gas components into said lower gas inlet assembly, the gas components flowing through the junction between the throat tube of the lower gas assembly and the lower part of the sedimentation tube and drawing a slurry flowing down in the sedimentation tube into the lower gas inlet assembly, the mixture of the gas components and the slurry entering into the reaction zone vessel and rising in the reaction zone vessel, wherein the gas components react in the presence of the slurry and continues to rise in the reaction zone vessel;

ii) at least a portion of the slurry flowing back into the sedimentation tube from the upper part of the sedimentation tube and descending down the sedimentation tube, then being drawn into the lower gas inlet assembly and mixed with gas introduced into the lower gas inlet assembly;

iii) repeating steps (i) and (ii).

Brief description of the drawings

Figure 1 shows the structure of a slurry-bed reactor of an example of the present invention.

Figure 2 shows the detailed structure of the lower gas inlet assembly of a slurry-bed reactor of an example of the present invention.

Figure 3 shows the structure of the sedimentation tubes of a slurry-bed reactor of an example of the present invention. Figure 4 shows the structure of the cannular heat exchange tubes of a slurry-bed reactor of an example of the present invention.

Figure 5 shows the structure of the top segregation means of a slurry-bed reactor of an example of the present invention.

The reference signs in drawings and this text are as follows: Reactor housing 1

Lower gas inlet 2

Surface level of the slurry 3

Heat exchange tube bundles 4 Sedimentation tubes 5

Reaction zone vessel 6

Filter 7

Liquid outlet 8

Heat exchange tube inlet 9 Heat exchange tube outlet 10 Segregation means 1 1 Separating plate 12

Foam eliminator 13

Upper outlet 14 Gas inlet tube 15

Throat tube 16

Descending pipe 17

Pipette 18

Fluid aspirator 19

Mixer tube 20

Narrowing portion 21

Vessel flared opening 22 Distributor 23 Sedimentation tube flared opening

Feeding pipe 25

Upper material fluid inlet

Lower outlet 27

Outer tube 28

Inner tube 29

Separator 30

Downstream pipe 31

Downstream pipe outlet 32 Detailed Description of the Invention

A "range" of a value disclosed herein is commonly in the form of lower limit and upper limit for the value. For any particular value there can be given herein 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, 110-120 and 80-120. 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, any of the technical features and preferred features described herein can be combined in any appropriate order.

Unless otherwise specified or clear otherwise from the context, any of the steps described herein can be performed in the order presented, or in any appropriate other order. For example, said method comprises steps (a) and (b) preferably includes that 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 preferably 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).

Some preferred embodiments of the present invention will be discussed hereinafter in combination with the drawings. A person skilled in the art could understand that various equivalent alternations, modifications and combinations may be made to these embodiments without departing from the scope limited by the claims of the present invention. New technical solutions obtained by above-referenced alternations, modifications and combinations are within the scope of the present invention. It should be noted that the equipments or devices in the drawings of the present invention are not drawn in actual ratio. In particular, the length- width ratio of some slender components is changed, the diameter of some slender components, for example sedimentation tubes, may be enlarged for clearer observation. The method of the present invention could be used for any suitable slurry-bed reaction system known in the art, and is not limited to the equipment or system described herein.

Figure 1 shows one specific embodiment of the slurry-bed reactor of the present invention. The reactor comprises housing 1 and components arranged within the housing 1, wherein said components comprise, from top to bottom, a upper outlet 14, a foam eliminator 13, a separating plate 12, segregation means 11, slurry, heat exchange tube bundles 4, sedimentation tubes 5, reaction zone vessel 6 and lower gas inlet assembly.

The lower gas inlet assembly in the reactor shown in Figure 1 is Venturi equipment. As shown in Figure 2, the lower gas inlet assembly is consisted of an gas inlet tube 15, a narrowing portion 21, a throat tube 16, a fluid aspirator 19 and a mixer tube 20. The Venturi equipment has large diameter at the position of the gas inlet tube 15 and the diameter narrows down gradually at narrowing portion 21. The throat tube 16 is in fluid communication with the pipette 18. The air inlet tube 15 extends beyond the reactor housing 1, and is connected with the outer feed gas resource or the pump to introduce gas needed for the reaction into the reactor. After entering into the reactor by the gas inlet tube 15, the gas flow increases when passing through the narrowing portion 21 and the pressure is reduced. The throat tube 16 is in fluid communication with the pipette 18 at the lower end of the sedimentation tubes 5 through the opening on the side wall of the throat tube 16. The materials in the sedimentation tubes 5 is siphoned into the throat tube 16 through the pipette 18 by the pressure difference exists between the gas whose pressure is reduced when passing through the throat tube 16 and the pipette 18, and are delivered upwardly with the gas through the throat tube 16. At the same time, severe fragmentation and mixing effect occur between the gas and slurry under high gas flow and form the gas-slurry mixture. The throat tube 16 inserts into the fluid aspirator 19 and mixer tube 20, and the slurry from the outside of the sedimentation tubes 5 is brought into the mixer tube 20 under the same mechanism. The slurry from the outside of the sedimentation tubes 5 is mixed with the gas-slurry mixture from the throat tube 16, the resulted mixture is delivered upwardly through the vessel flared opening 22 and distributed evenly through the distributor 23, and finally into the reaction zone vessel 6. The reaction zone vessel can be of any suitable shape or size. The ratio of the diameter of the reaction zone vessel 6 to that of the reactor housing 1 is 0.7-0.97, preferably 0.71 ·, 0.73 > 0.75 , 0.7S , 0.S0, 0.81 , 0.82. 0.S3 , 0.84. 0.S5 , 0.S6, 0.S7, 0.SS , 0.S9, 0.90, 0.92 > 0.93 , 0.94, 0.95 , 0.96, 0.97. The ratio can also be any value within the range formed by the combination of any aforementioned value. The large diameter ratio make most of volume under the surface level 3 of the slurry be positioned in the reactor vessel 6 to conduct the slurry-bed reaction. The ratio of the height of the reaction zone vessel 6 to that of the entire reactor housing 1 is 0.5-0.9, preferably 0.6, 0.65 , 0.7, 0.75 , 0.8 , 0.85 or any value within the range formed by the combination of any aforementioned value. The distributor 23 of the present invention could be any common device in the art which is suitable for uniform distribution of gas-solid-liquid. In a preferred embodiment, the distributor 23 is a distribution plate comprising a large number of through-hole. The size and number of the through-hole in the distribution plate can be selected by the person skilled in the art according to the specific reaction process and reactor structure. These through-holes can be distributed on the distribution plate in the form of concentric circles, involute, flower petal, star, random pattern and so on.

The reactor of the present invention may utilize n pieces of

sedimentation tubes, wherein n is an integral number between 2 to 20 according to the reactor size. These sedimentation tubes 5 are arranged around the central axis of the reactor along the axis direction of the reactor. In the present invention, the axis means the imaginary line extending vertically through the reactor center line. Said n pieces of sedimentation tubes can be arranged around the reactor's centerline in uniform symmetrical order, or non-uniform order. Figure 3 shows the detailed structure of the sedimentation tubes 5. As shown in Figure 3, each sedimentation tube 5 is comprised of a sedimentation tube flared opening 24, a feeding pipe 25 and a pipette 18. The diameter di of the pipette 18 is less than 1/n of the

circumference of the throat tube 16's cross section that is perpendicular to the vertical axis of the reactor. The diameter di is preferably less than l/2n of the circumference of the throat tube 16's cross section that is perpendicular to the vertical axis of the reactor. The feeding pipe 25 and the pipette 18 is connected at the part with involute shape. The sedimentation tube flared opening 24 has an eccentric funnel shape, which means that the cross section of the upper material fluid inlet 26 of the sedimentation tube flared opening is circular, and the cross section of the lower outlet 27 is also circular. The centers of the two circles do not overlap in the vertical direction, instead they shift with some distances between them. In a preferred embodiment of the present invention, the ratio of the diameter of the upper material fluid inlets 26 to the radius of the reactor housing 1 is 0.1-1, more preferably 0.2-1, more preferably 0.3-1, more preferably 0.4-1, more preferably 0.5-1, more

preferably 0.6-1. The structure of the flared opening 24 ensures the internal circulation of the most slurry through the sedimentation tubes.

With further reference to Figure 1, the height of the upper end of the sedimentation tubes 5 is close to that of the surface level 3 of the slurry and is submerged under surface level 3. The vertical height difference between the upper end of the sedimentation tubes 5 and the surface level 3 of the slurry is preferably 0.1-2 meters, more preferably 0.2-1.5 meter, more preferably 0.3-1.2 meter, more preferably 0.4-1 meter, more preferably 0.5-0.8 meter, most preferably 0.6-0.7 meter. The height of the reaction zone vessel 6 is close to that of the lower outlet 27 of the sedimentation tube flared opening 24 of the sedimentation tubes 5, and is lower than the height of the lower outlet 27. The vertical height difference between the upper limb of the reaction zone vessel 6 and the lower outlet 27 is preferably 0.1-2 meters, more preferably 0.2-1.5 meter, more preferably 0.3-1.2 meter, more preferably 0.4-1 meter, more preferably 0.5-0.8 meter, most preferably 0.6-0.7 meter. The ratio of the height of the surface level 3 in the reactor to that of the reactor housing 1 is 0.5^0.9, more preferably 0.6^0.8, more preferably 0.65^0.75, more preferably 0.7 in order to ensure enough segregation space in the upper part of the reactor. The size, height of each component described above and height difference among them can be set by a person skilled in the art according to specific technical requirements.

Multiple groups of heat exchange tube bundles 4 are provided to improve heat exchange in the reactor. The fluid can be cooled or heated in the heat exchange tube bundles according to the endothermic or exothermic properties of the specific reaction process in the reactor so as to cool the exothermic system or supply heat to the endothermic system to maintain the temperature of the reaction system within the defined range. As shown in Figure 4, each of the heat exchange tube bundles 4 has a cannular structure and is comprised of an outer tube 28 and an inner tube 29. In an embodiment, said heat exchange fluid flow into the outer tube 28 of the heat exchange tube bundles 4 through heat exchange tube inlet 9, exchange heat with the slurry in the outer tube 28 and then flow into the inner tube 29 and flow out from the heat exchange tube outlet 10. The heat exchange fluid used in the present invention could be any fluid known by a person skilled in the art, for example, air, nitrogen, inert gas, water, coolant oil, supercritical fluid and so on, wherein the supercritical fluid is preferably supercritical carbon dioxide. In an embodiment of the present invention, the reaction in the reactor is exothermic reaction. Said heat exchange fluid is water whose oxygen and salt has been removed. The oxygen is removed to avoid oxidation of the heat exchange tube bundles 4 to effectively extend the life of the device. The salt is removed to prevent scaling. The heat exchange fluid gasifies into steam after absorbing heat of the reaction system. The steam flows through the inner tube 29 and flows out from the heat exchange tube outlet 10.

Segregation means 11, a separating plate 12 and a foam eliminator 13 are provided above the surface level 3. After the reaction in the slurry, the gas-material fluid including part of liquid and solid rises to the segregation means 11 which is comprised of a separator 30, downstream pipe 31 and downstream pipe outlet 32. The separator 30 could be any separator known in the art that can be used for the gas, liquid and solid three-phase segregation, preferably liquid cyclone. After the liquid and solid are removed, the gas material rises from the segregator through the separating plate 12, then the foam eliminator 13 in which the remaining foam, i.e. small amount of remaining liquid, is removed, and then is expelled from the upper outlet 14 of the reactor. The liquid and solid components segregated from the separator 30 flow down the downstream pipe 31 and back into the slurry from the downstream pipe outlet 32. In a preferred embodiment of the present invention, said downstream pipe 31 extends along the inner wall of the reactor housing 1. In a preferred embodiment of the present invention, the reactor of the present invention comprises 1-20, preferably 1-15, preferably 1-12, preferably 1-10, preferably 3-8, preferably 5-7 segregation means 11. These segregation means 11 are distributed evenly around the inner wall below the separating plate 12. The downstream pipe 31 of the segregation means extends downwardly along the inner wall of the reactor housing 1. In a preferred embodiment of the present invention, the outlet 32 of the downstream pipe 31 is inserted under the surface level 3. In another preferred embodiment of the present invention, the downstream pipe outlet 32 is horizontally oriented towards the inner wall of the reactor housing 1. In a preferred embodiment of the present invention, the slurry-bed reaction is shown as follows: the feed gas is introduced into the reactor through the gas inlet tube 15; the gas flow increases when passing the narrowing portion 21 ; the pressure is reduced and the pressure difference is thus formed in the reactor; when gas with the reduced pressure passes through the throat tube 16, the slurry in the sedimentation tubes 5 is siphoned into the throat tube 16 through the pipette 18 by internal-external pressure difference.

Severe fragmentation and mixing effect can occur between the gas and slurry under high gas flow velocity. The mixture of the gas and slurry is delivered upwardly from the throat tube 16 and through the fluid aspirator 19 at high velocity. At the same time, the slurry from the outside of the sedimentation tubes 5 is brought into the mixer tube 20 under the same mechanism. The slurry from the outside of the sedimentation tubes 5 is mixed in the mixer tube 20 with the gas-slurry mixture from the throat tube 16. The obtained mixture ascends into the reaction zone vessel 6 through the flared opening 22 and the distributor plate 23.

The gas-slurry mixture passes through the reaction zone vessel 6 in bubble state to the upper part of the reactor, and reacts in the ascending process, and generate products in liquid or gas state, wherein the liquid product is filtered to separate from the solid through the filter 7 disposed at the side wall of the middle part of the reactor and is introduced by the liquid outlet 8. The gas product, by-product and unreacted feed gas ascend to depart from the slurry, and go through the foam eliminator 13 and are expelled from the outlet 14 after the liquid and solid mixed therein are removed by the segregation means 11. The slurry segregated from the segregation means descends along the downstream pipe 31 around the periphery of the reactor, and back into the slurry through downstream pipe outlet 32.

As described above, a portion of the slurry entrained in the gas flow down the downstream pipe 31 and back into the slurry after being segregated in the segregation means 11. In addition, a part of the slurry ascending along the reaction zone vessel to the upper side of the upper surface of the slurry would descend under gravity. The downstream pipe 31 is arranged along the inner wall of the reactor around the reactor periphery. The sedimentation tubes 5 are arranged around the axis of the reactor along the axis direction of the reactor and have specifically designed structure of flared opening 24. Most of the descending slurry are thus collected in the sedimentation tubes 5 through the flared opening 24, and enter into feeding pipe 25 through lower outlet 27. Under syphoning effect formed at the bottom throat tube 16 and driven by the tube density difference between the internal and the external, the slurry enter into the throat tube 16 through the pipette 18, forming the main internal circulation of the slurry. Under the drive by the slurry density difference between the internal and external reaction zone vessel 6, a small amount of slurry outside of the reaction zone vessel 6 and sedimentation tubes 5 form secondary internal circulation with slower velocity.

It can be understood therefore that examples of the reactor of the present invention can improved the lower gas inlet assembly compared with the traditional inner-circulating reactor. The Venturi effect formed by the low pressure by the constriction of the throat tube 16 promote the gas-liquid mixing and mass transfer, and the syphoning effect increase the flow of the slurry in the sedimentation tubes 5, can improve the slurry circulation and increase the reactor efficiency and reduce the back-mixing.

Compared with the prior art, the present invention has the advantages as follows. The gas inlet assembly uses the Venturi effect in examples of the invention to improve the mixing of feed gas and slurry and mass transfer efficiency, and promote the reaction. The low pressure at the feed gas inlet is used to form the siphon effect which can increase the flow of the slurry circulation in the reactor, reduce the back-mixing and thereby to increase the space time yield of the reactor and reduce reactor investment.

The slurry materials collected by the segregation means at the top of the reactor descend along the tube wall, which avoids the disturbance of the downstream pipe slurry to the reactor inner circulation. In addition, the special horizontal orientation design of the outlet can avoid the lifting effect of the ascending gas to the slurry in the feeding pipe in some examples, and thereby increase the segregation effect at the top and allow for higher reactor operating gas speed and improve the space utilization and space time yield of the reactor.

The circulating velocity of the slurry in the reactor is increased through aforementioned structure modification, increasing the heat transfer efficiency, and avoiding the limitation of heat exchange ability on the productivity.

Examples

The present description is further illustrated by the following examples. In the following examples, synthesis gas mainly including hydrogen and carbon mono-oxide gas is used as raw material to synthesize the product of hydrocarbon oil and dimethyl ether (DME). It should be noted that the reactor and method of the present invention can be also used in relation to other slurry-bed reaction.

Example 1 In example 1 , the mixed gas of hydrogen and carbon monoxide is used as the raw material to synthesize hydrocarbon oil in the slurry-bed reactor. The synthetic hydrocarbon oil is liquid product and is expelled from the liquid outlet 8 after the solid is removed through filtration by the filter 7. Specifically, a slurry-bed reactor as shown in Figure 1 is used in this example, the inner diameter of the slurry-bed reactor housing is 1 meter, the longitudinal height of the reactor is 25 meters, and the height of the fluid level in the reactor is 18 meters. The reaction zone vessel is disposed along the central axis of the reactor, with inner diameter of 0.92 meter and height of 15 meters. 6 pieces of sedimentation tubes with inner diameter of 0.028 meter are arranged around the central axis of the reactor. The diameter of the upper material fluid inlet of the sedimentation tubes upper flared opening 24 is 0.3 meter. The vertical height difference between said upper material fluid inlet 26 and the surface level 3 of the slurry is 0.6 meter. The diameter of the throat tube is 0.25 meter, and the diameter of the pipette is 0.02 meter. The pressure within the reactor is maintained to be 2MPa. Water with oxygen and salt removed is used as condensing agent. The water is made to go through the heat exchange tube bundles to maintain the temperature of the reaction system to be 220 ^° C .

The synthesis gas of H ₂ /CO with volume ratio 2: 1 is used as feed gas. The synthesis gas is provided through the bottom gas inlet of the reactor with superficial gas velocity of 0.371 m/s. The slurry in the reactor is slurry formed by the cobalt-based catalyst suspended in liquid paraffin solvent and the weight content of the solid in said slurry is 15%. The percentage is calculated based on the total weight of the slurry. The cobalt-based catalyst is Co/Zr0 ₂ /Si0 ₂ catalyst with particle size of 50 micrometer which is provided by Shanghai Advanced Research Institute of the Chinese Academy of Science. As the solvent, the liquid paraffin is hydrocarbon mixture with the carbon atom number of approximately 18-30. See Jie Chang, et al. Chin J Catal, 26 (10), 859-868, 2005 for more details about the catalyst slurry.

The CO content in the tail gas flow drawn from the upper outlet 14 is determined by the Shimadzu GC-14C gas chromatography. The conversion efficiency of CO is calculated to be 59.9% when compared to CO molar quantity supplied to the bottom inlet. Thus the space time yield of the reactor is 68.02 kg/h/m according to the calculation with the feed gas amount and reactor volume. In addition, the applicant used the reactor described in CN 201052457Y with the same process conditions for contrast experiment. The result shows that the CO conversion efficiency at the gas outlet of the reactor is 51.53%, and the space time yield of the reactor is 58.51 kg/h/m . It can be seen that compared with the reactor of prior art, the CO conversion efficiency and the space time yield of the slurry-bed reactor of the present invention has increased by about 16.3% as a result of the improved mixing and mass transfer efficiency.

Example 2

In example 2, the mixed gas of hydrogen and carbon monoxide is used as the raw material to synthesize dimethyl ether in the slurry-bed reactor. The reactor is designed substantially the same as the reactor of Example 1 except that the reactor of Example 2 does not need the filter 7 and liquid outlet 8 for the product DME is in gaseous state and is expelled from the upper outlet together with the tail gas.

The pressure within the reactor is 4MPa. Water with oxygen and salt removed is used as the condensing agent. Said water went through the heat exchange tube bundles to maintain the temperature of the reaction system to be 270 ^° C . The feed gas is mixed gas of H ₂ /CO with volume ratio of 1 : 1. The catalyst is bi-functional catalysts consisting of catalyst C301 for industrial synthesis of methanol and dehydrated alumina catalyst. These catalysts are suspended in liquid paraffin solvent, forming a slurry with 15% solids in weight ratio. The percentage is calculated based on the total weight of the slurry. The boiling point of the liquid paraffin solvent is higher than 340 ^° C , and the average molecular weight is 345, see Junwang Guo, et al. J Fuel Chem Techno, 26 (4) 321-325, 1998 for more details about slurry catalysts.

The mixed gas is feed into the bottom gas inlet of the reactor with superficial gas velocity of 0.136 m/s. The CO content in the tail gas flow drawn from the upper outlet 14 is determined by the Shimadzu GC-14C gas chromatography. The CO conversion efficiency is calculated to be 33.64% by comparing with the molar quantity of CO supplied to the bottom inlet. Thus the space time yield of the reactor is 44.07 kg/h/m according to the calculation based on the feed gas amount and reactor volume. In addition, the applicant used the reactor described in CN 201052457Y under the same process conditions as a comparing experiment. The result shows that the CO conversion efficiency at the gas outlet of the reactor is 31.2%, and the space time yield of the reactor is 40.87 kg/h/m . Thus, the CO conversion efficiency and the space time yield of the slurry-bed reactor of the present invention has been increased by about 8% comparing with the reactor of the prior art.