CN101785981B - Low resistance fixed bed reactor - Google Patents

Abstract

The invention relates to a low resistance fixed bed reactor, mainly composed of a catalyst basket 3 provided with a gas inlet 14 and a gas outlet 15. Fluid is adopted as cooling medium to remove reaction heat into fluid catalysis reaction and heat-transfer process, and the fixed bed reactor is especially applicable to reaction process such as ammonia feed gas synthesis by high pressure methanation refining and has the beneficial effects of low resistance, large catalyst charge quantity and good effect.

Description

A kind of low resistance fixed bed reactor

Technical field

The present invention is a kind of catalytic reaction device and application process, for fluid catalytic reaction and diabatic process, belongs to field of chemical engineering, is specially adapted to the courses of reaction such as the refining syngas for synthetic ammonia of high-pressure methanation.

Background technology

For being all exothermic reactions as reactions such as ammonia synthesis, methyl alcohol are synthetic, methanations, fixed bed reactors commonly used have axial flow reactor and radial reactor, radially the tower resistance is low but because establishing inside and outside gas distributing cylinder, make capacity utilization little, catalyst efficiency is low, axially tower has plot ratio height and the high advantage of catalyst efficiency, but resistance is larger.

The inventor all is explained in detail this in the joint production of the high-pressure type methyl alcohol such as granted patent ZL98240557 thermal balance high-pressure energy-saving reactor and patent ZL93105920.8 and ammonia, but complex structure, resistance is larger.

The present invention, for overcoming above-mentioned prior art shortcoming, provides a kind of lower resistance, the low resistance fixed bed reactor that the catalyst loading amount is large, effective.

Summary of the invention

While for picture, using high-pressure methanol methanation technology purifying gas as raw material for synthesis of ammonia, advance methanator CO+CO₂content generally<0.1%, lower than conventional 0.5～0.7%, therefore reaction heat is few, can not self-heating need to use outer heat for maintaining reaction temperature, in patent ZL98240557 thermal balance high-pressure energy-saving reactor, this is explained in detail, can not lean on high-pressure methanation tower heat exchangers in towers or methanation exhaust gas to heat into the methanation unstripped gas and reach reaction temperature, in the joint production of the high-pressure type methyl alcohol such as inventor's patent of invention ZL93105920.8 and ammonia, methanation pressure can be up to 30MPa, the methanation reaction temperature again can be up to 300～450 ℃, therefore employing compression shell, with cold gas, protect, low temperature feedstock gas through between pressurized shell and catalyst layer cold air path outside tower, then successively with methanator, go out tower hot gas intensification heating and advance again methanator, perhaps more further with outer heat exchanger heating, perhaps in methanator, with electric heater, further heat, simultaneously because methanation reaction heat is few, therefore can adopt adiabatic reaction, the high pressure catalyst is divided into to upper and lower two layers, unstripped gas is divided into two into to two strands, react up and down respectively the flow through catalyst layer reaction of reverse flow or subtend, because gas flow reduces to 1/2 through the catalyst layer height, and tolerance is divided into two, flow velocity reduces by 1/2, therefore be reduced to original 1/8 through the beds resistance, reality can reach 1/5～1/7.

For advancing, the unstripped gas concentration that participates in reaction in tower gas is higher, the catalytic reaction that reaction heat is large, can in upper and lower catalyst layer, heat exchanger tube be set, the heat transferring mediums such as water shift out reaction heat, when synthesis pressure is not high, for example lower than the methyl alcohol of 10MPa is synthetic, catalyst layer directly can be contained in housing.

The invention provides a kind of low resistance fixed bed reactor, by thecatalyst basket 3 withgas feed 14 andgas vent 15, formed, wherein by middle part,top catalyst layer 41 and the lowercatalytic agent layer 42 by gas distributor orgas collector 8 forms the catalyst layer incatalyst basket 3,space 31 and top gas thathead tube 6 connects between top catalyst layer and catalyst baskettop end socket 4 import andexport 155,space 32 andgas feed 14 thatlower tube 9 connects betweencatalyst support plate 12 and catalyst basket low head, take over 7 and connectgas collector 8 andgas vent 15, unreacted feed gas is divided into two strands bycentral gas distributor 8, respectively through the upwards mobile gas 51 oftop catalyst layer 41, after flowing downward gas 52 reverse flow reactions, 42 reaction of lower catalytic agent layer go out tower, perhaps unreacted feed gas is divided into two stocks not through flow downwardreaction gas 53 and through lowercatalytic agent layer 42 flowingreactive gas 54 subtend flowing reactives upwards oftop catalyst layer 41, then two strands of reaction gases converge throughgas vent 15 and go out tower in thegas collector 8 in the middle part of catalyst layer.

In a better example of the present invention, thecatalyst basket 3 of described equipment is provided with for heating into the central tube 5 of the electric furnace 60 of tower unstripped gas, central tube 5 bottoms and raw material gas inlet 14 link, thespace 31 that 41 the upper catalyst basket upper covers in top and top catalyst layer are 4 is communicated with, between communicating pipe 11 andupper space 31 and catalystporous bearing plates 12 and catalyst basket low head,space 32 is communicated with, andreaction gas outlet 7 links catalyst baskets middlepart collection chambers 8 and bottomreaction gas outlet 15.

In a better example of the present invention, the compression shell 1 of described equipment and catalyst basket the two have the cold air path 22 directly be not communicated with catalyst layer to link shellcold air import 21 and bottomcold air outlet 23,cold air outlet 23 links the outer import 24 from heat exchanger 61 of tower, the outlet 25 of heat exchanger 61 links outer heat exchanger 62 imports 26, the outlet 27 of heat exchanger 62 links catalystbasket gas feeds 14,reactor heat outlet 15 with from heat exchanger hot gas import 28, link.

In a better example of the present invention, the catalyst of described equipment directly is contained in thecatalyst basket 3 of pressurized, catalyst layer is divided into upperstrata catalyst layer 41 and lower floor'scatalyst layer 42 bycentral gas distributor 8, be provided with set ofheat exchange tubes 71 and set ofheat exchange tubes 72 in upper and lower two catalyst layers, with heat-conducting medium for example water remove catalyst bed reaction heat.

The accompanying drawing explanation

Below in conjunction with accompanying drawing, illustrate.

Fig. 1 is the low resistance fixed bed reactor schematic diagram that gas is divided into two bursts of upper and lower reverse flow.

Fig. 2 is that gas is divided into two strands of low resistance fixed bed reactor schematic diagrames that upper and lower subtend is mobile.

Fig. 3 is the built-in low resistance fixed bed reactor schematic diagram that adds electrothermal stove.

Fig. 4 is the low resistance fixed bed reactor schematic diagram that set of heat exchange tubes is arranged.

The specific embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in detail.

Fig. 1 is the low resistance fixed bed reactor schematic diagram that gas is divided into two bursts of upper and lower reverse flow.Figure medium or low resistance power reactor head has cover plate 2 andcold air import 21 is arranged and the housing 1 ofoutlet 23, cover plate 2 and housing 1 use high-pressure bolt link, in housing, there arecatalyst basket 3 andtop end socket 4 use bolt and nuts to link, upper connectingtube 6links end socket 4 and hot gas imports andexports 155, takes over 7 connectionlow head 10 hot gas and imports andexports 15, catalystporous bearing plates 12 is arranged atcatalyst basket 3 bottoms, in catalyst basketcylindrical shell 3, there isgas distributor 8 to link hot gas and import andexport adapter 7,catalyst basket 3 is bearing in shell 1low head 10 by the bottom supporting frame, in figure, 17 is the catalyst tremie pipe, 18 is temperature tube, when for the high-pressure methanation tower, from gas CO+CO after the alcohol after high-pressure methanol tower distribution methyl alcohol₂<0.1%, pressure 11～32MPa, 30 ℃ of temperature are upper and lower, entermethanator shell 1 and 3 cold air paths 22 of catalyst basket bycold air import 21, so that shell wall keeps low temperature, go out tower by bottomcold air outlet 23, exhaust gas is through external heat-exchanging, temperature is raised to as 230～450 ℃, by bottomhot air intake 14 through managing 7 togas distributor 8, be divided into the reaction gas 51 that makes progress throughtop catalyst layer 41, thespace 31 that is reacted to 4 of top end sockets above catalyst under 230～350 ℃ goes out tower through upper connectingtube 6top exits 155, reaction gas 52 reacts under 230～350 ℃ through lowercatalytic agent layer 42 downwards, theadapter 9 in thespace 32 through connecting 10 ofsupport plate 12 and bottom bulkheads goes out tower by outlet atbottom 15, after converging, go two strands of exhaust gas heat exchanger to reclaim reaction heat.

Fig. 2 structure and mark and Fig. 1 have much identical, no longer illustrate, the gas that different from Fig. 1 is in Fig. 2 is divided into two bursts of upper and lower subtends and flows, advance tower attop catalyst layer 41 flowing reactive from top to bottom by tophot air intake 155 respectively through being heated to more than 230 ℃ unstripped gas two parts, another part bybottom inlet 14 through manage 9 gas 52 that flow from bottom to top toporous bearing plates 12 in lowercatalytic agent layer 42, upper and lower two strands of reaction gases in middlepart gas collector 8, converge through manage 7 and outlet atbottom 15 go out tower.

Fig. 3 is the built-in low resistance fixed bed reactor schematic diagram that adds electrothermal stove.In figure in reactor with electrical heating counter current flow reactor, different from Fig. 1 one is in catalyst basket, to have in central tube 5 electric heater 60 is housed, during for driving heating reduction catalyst or heat supply while normally producing, the 2nd, be provided with the communicating pipe 11 that is communicated withend socket space 32 in 31He bottom, the interior space of top upper cover, the 3rd, tower external heat exchanger is arranged, exhaust gas heat exchanger 61 and outer heat exchanger 62 are advanced in methanation,cold air outlet 23 joins with the import 24 of heat exchanger 61, heat exchanger 61 outlets are connected with outer heat exchanger 62 imports 26, heat exchanger 62 outlets 27 are connected withhot air intake 14, during for the high-pressure methanation reaction, 35 ℃ of upper and lower cold air of temperature bycold air import 21 through housing and catalyst basket passage 22 approximately 40 ℃ of upper and lower temperature go out tower byoutlet 23, with 300 ℃ of upper and lower reaction gas heat exchange ofmethanation outlet 15 for example be warmed up to 270 ℃ upper and lower, be warmed up to reactor bottomhot air intake 14 in 300 ℃ through 350 ℃ of left and right heat exchange of outer heat exchanger temperature again and advance central tube, arrive thespace 31 in topupper cover 4, unstripped gas is divided into two parts, a part by upper under throughtop catalyst layer 41 reaction, another part communicating pipe 11 to the interior space ofbottom head 32 baffling upwards through theporous bearing plates 12 upwards flowing reactive of lowercatalytic agent layer 42 of upwards flowing through, reach CO+CO₂≤ 10ppm, two strands of reacting gas middlepart collection chamber 8 converge through manage 7 go out tower to add thermal response toheat outlet 15 to automatic heat exchange device 61 before cold air drop to<70 ℃, then the cooler or further cooling through ammonia cooler that anhydrates, separate moisture content and make ammonia-synthesizing material gas.

Fig. 4 is the low resistance fixed bed reactor schematic diagram that set of heat exchange tubes is arranged.Be mainly used in the situation that reaction heat is large, reaction pressure is lower, for example methanol synthesis reactor.Fig. 4 is that catalyst directly is contained in thecatalyst basket 3 of pressurized, catalyst layer is divided into upperstrata catalyst layer 41 and lower floor'scatalyst layer 42 bycentral gas distributor 8, be provided with set ofheat exchange tubes 71 and set ofheat exchange tubes 72 in upper and lower two catalyst layers, with heat-conducting medium for example water remove catalyst bed reaction heat.

Embodiment 1: producing 300000 tons per year is that 1000 ton per day ammonia station-services and ammonia synthesis equipressure are that 20MPa carries out the high-pressure methanol methanation, with internal diameter φ 1600 methanators, J105 type methanation catalyst for 15 meters of catalyst layer height overalls, carry out methanation reaction at 250 ℃ of upper and lower temperature, thick high-pressure methanol advances methanator tolerance composition and the results are shown in Table 1.Adopt the present invention to adopt Fig. 1 counter current flow methanator, calculate to such an extent that tower pressure reduction is 7KPa, be only in sequence number 2 single shaft to 1/8 of tower pressure reduction 56KPa.

Subordinate list 1

beneficial effect

Compared with the prior art the present invention has remarkable advantage, and the one, can be designed to the ratio of height to diameter larger axis to reactor, reduce equipment investment under same catalyst and production capacity; The 2nd, gas is divided into not flowing reactive in upper and lower two layers of catalyst layer of two stocks, in gas, through flow velocity and the distance of catalyst, all reduces half, thus resistance is only the full bed of all gas flow 1/8, significantly reduce resistance and energy consumption; The 3rd, catalyst volume rate and production intensity specific diameter improve to tower; The 4th, can adopt gas on upper and lower beds before and after different times adopt respectively counter current flow or reverse flow, take full advantage of bed different parts catalyst flow path and improve catalyst service life.

By above-mentioned legend and embodiment, theme of the present invention has been done to abundant description, according to design spirit of the present invention, those of ordinary skill in the art can easily carry out various variations.In the present inventionlower grid plate 12 can be designed to low head equally ellipse be convenient to unload catalyst, location grid position supporting central tube and communicating pipe can be established in top, central gas gas collection or steam separator can be designed to the shapes such as rhombus, annular, outer multi hole grid or the gillis that can be covered with stainless steel cloth, inside have the turnover of connection tracheae and have the aperture tube wall.

Claims (4)

1. a low resistance fixed bed reactor, mainly by the catalyst basket (3) with gas feed (14) and gas vent (15), formed, it is characterized in that the catalyst layer in catalyst basket (3) has the top catalyst layer (41) of gas distributor or gas collector (8) and lower catalytic agent layer (42) to form by middle part, space (31) and top gas that head tube (6) connects between top catalyst layer and catalyst basket top end socket (4) are imported and exported (155), lower tube (9) connects space (32) and the gas feed (14) between catalyst porous bearing plates (12) and catalyst basket low head (10), take over (7) and connect gas collector (8) and gas vent (15), unreacted feed gas is divided into two strands by central gas distributor (8), respectively through the upwards mobile gas (51) of top catalyst layer (41), after flowing downward the reaction of gas (52) reverse flow, lower catalytic agent layer (42) reaction goes out tower, perhaps unreacted feed gas is divided into two stocks not through flow downward reaction gas (53) and through lower catalytic agent layer (42) flowing reactive gas (54) subtend flowing reactive upwards of top catalyst layer (41), then two strands of reaction gases converge through gas vent (15) and go out tower in the gas collector (8) in the middle part of catalyst layer.

2. a kind of low resistance fixed bed reactor according to claim 1, it is characterized in that catalyst basket (3) is provided with for heating into the central tube (5) of the electric furnace (60) of tower unstripped gas, central tube (5) bottom and raw material gas inlet (14) link, top is communicated with the space (31) between catalyst basket upper cover (4) on top catalyst layer (41) face, communicating pipe (11) is communicated with the space (32) between the catalyst basket low head with upper space (31) and catalyst porous bearing plates (12), take over (7) and link catalyst basket middle part collection chamber (8) and gas vent (15).

3. a kind of low resistance fixed bed reactor according to claim 1, the two has the cold air path (22) directly be not communicated with catalyst layer to link shell cold air import (21) and bottom cold air outlet (23) to it is characterized in that compression shell (1) and catalyst basket (3), cold air outlet (23) links the outer cold air import (24) from heat exchanger (61) of tower, the outlet (25) of heat exchanger (61) links outer heat exchanger (62) import (26), the outlet (27) of heat exchanger (62) links catalyst basket gas feed (14), reactor heat outlet (15) with from heat exchanger hot gas import (28), link.

4. a kind of low resistance fixed bed reactor according to claim 1, it is characterized in that catalyst directly is contained in the catalyst basket of pressurized (3), catalyst layer is divided into upper strata catalyst layer (41) and lower floor's catalyst layer (42) by central gas distributor (8), be provided with the first set of heat exchange tubes (71) and the second set of heat exchange tubes (72) in upper and lower two catalyst layers, with heat-conducting medium water, remove catalyst bed reaction heat.

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