CN2093031U

CN2093031U - Recirculating fluidized bed reactor with uniform flow field and free from wall effect

Info

Publication number: CN2093031U
Application number: CN 91216163
Authority: CN
Inventors: 李静海; 别如山; 郭慕孙; 吴文渊; 杨励丹
Original assignee: Harbin Institute of Technology; Institute of Chemical Metallurgy CAS
Current assignee: Institute of Process Engineering of CAS; Harbin Institute of Technology
Priority date: 1991-06-17
Filing date: 1991-06-17
Publication date: 1992-01-15

Abstract

The utility model relates to a recirculating fluidized bed reactor with a uniform flow field and free from wall effect, which is composed of a reactor body, a two-stage cyclone separator, a recirculating leg for solid particles and a communicating pipe for connecting the reactor body to the recirculating leg. The recirculating fluidized bed reactor with a uniform flow field and free from wall effect is characterized in that an original straight pipe reactor is changed into a reactor with a cross section contracted and expanded alternately to compose the reactor body. In the recirculating fluidized bed reactor with a uniform flow field and free from wall effect, an air cushion is formed nearby a wall surface to eliminate wall effect, and particles are all homogeneously distributed in a column zone with a necking cross section. The utility model which improves the performance of reactors and improves the yield and the quality of products can be used in chemical industry, energy industry, metallurgy industry, material industry, etc.

Description

Recirculating fluidized bed reactor with uniform flow field and free from wall effect

The utility model relates to a kind of circulating fluid bed reactor, particularly relates to a kind of even flow field wall-less effect circulating fluid bed reactor, belongs to the Dual-Phrase Distribution of Gas olid reactor.

Recirculating fluidized bed is a kind of Dual-Phrase Distribution of Gas olid reactor that development in recent years is got up, be widely used in the industry such as chemical industry, the energy, metallurgy and material, according to the difference of carrying out course of reaction in the reactor, circulating bed reactor can be divided into two kinds substantially: a kind of is that gas and particle are reactant, therefore needs continuous supply gas and particle (as burning of coal); Another kind is that particle is a catalyst, recycles (as petroleum catalytic cracking) in reactor.Summary visible (J.R.Grace, Chem.Eng.Sci., Vol.45, No.5, p, 1953-1966,1990) about circulation fluidized bed current situation and fluidal texture.The utility model reactor belongs to the circulating bed reactor of a kind of form in back, its structure as shown in Figure 1, it is mainly by reactor body (2), first order cyclone separator (3), the parts such as communicating pipe (8) of second level cyclone separator (4), solid particle circulation dipleg (6) (also as catalyst regenerator, being generally bubbling fluidized bed) and binding reactor body and circulation dipleg are formed.Communicating pipe (8) comprises the grain flux adjusting device usually.The air inlet (1) of reacting gas through being positioned at the reactor body bottom enters reactor body (2), under the effect of catalyst, react, and entrained catalyst particles enters first order cyclone separator (3) and second level cyclonic separation (4), after catalyst after the separation is regenerated in circulation dipleg (6), reenter the bottom of reactor body (2) through communicating pipe (8), repeat above process.Gas after the separation enters next step processing procedure via the gas vent (5) on second level cyclone separator (4) top.

Granule density radially uneven distribution is one of main drawback of circulating bed reactor (particularly to catalytic cracking reaction), in existing circulating bed reactor, center and wall region granule density difference can reach an order of magnitude, the center is a low concentration region, the gas entrained particles moves upward at a high speed, and wall region is a high concentration region, only there is a small amount of gas to pass through, particle speed is very low, sometimes even move downward, make gas contact and produce polarization with catalyst, this flow pattern has a strong impact on the performance of reactor, reduces the yield and the quality of product, especially short the and easy reactor that secondary response takes place to the reaction time, this problem is particularly outstanding, thereby is the focus of circulating bed reactor research and design always.Although taked multiple measure, as inner member, cocurrent flow descending etc., effect is also not obvious, and brings the difficulty of some processing and operation.Seek a kind of thorough solution uneven distribution, eliminate wall effect, the approach that produces even gas-solid suspension is an extremely important job.

The purpose of this utility model is: in order to solve radially skewness of existing recirculating fluidized bed middle particle concentration, eliminate wall effect, do not have the wall effect circulating fluid bed reactor and design a kind of even flow field.

The utility model and existing circulating bed reactor, mainly all by reactor body, first order cyclone separator, second level cyclone separator, forming communicating pipe of solid particle circulation dipleg and binding reactor body and circulation dipleg, being characterized in that reactor body adopts to be changed into by original straight tube reactor can produce air cushion to eliminate wall effect near wall, the cross section that forms uniform flow field is for replacing the reactor of convergent flaring.

The existing circulating bed reactor radially reason of uneven distribution formation is: wall is consistent for the trend that keeps minimum potential energy with particle to the effect of particle, thereby promoted the formation of uneven distribution, and caused the difference of center and wall region particle and fluid interaction intensity.Therefore, for avoiding the generation of uneven texture, must constantly change the proper motion trend of particle or air-flow; the failure energy minimization process; eliminate the factor that produces gas-solid action intensity difference, for this reason, reactor body of the present utility model adopts the cross section for replacing the reactor of flaring and convergent.

Specifically describe the utility model below with reference to accompanying drawing.

Fig. 1 is the structural representation of existing circulating bed reactor.

Fig. 2 is the structural representation of the utility model " even flow field wall-less effect circulating fluid bed reactor ".

Fig. 3 is the comparison schematic diagram of the utility model and existing circulating bed reactor structure and the distribution of corresponding granule density.

Fig. 3-a is reactor body structure of the present utility model and granule density radial distribution schematic diagram.

Fig. 3-b is traditional circulating bed reactor structure and granule density radial distribution schematic diagram.

Among the figure: 1-reaction gas inlet 2-reactor body 3-first order cyclone separator 4-second level cyclone separator 5-gas vent 6-solid particle circulation dipleg (also as catalyst regenerator, being generally bubbling fluidized bed) 7-keeps the gas access 8-binding reactor body of particle flow in the dipleg and the communicating pipe of circulation dipleg

By accompanying drawing as seen, the utility model is mainly by reactor body (2), and the communicating pipe (8) of first order cyclone separator (3), second level cyclone separator (4), solid particle circulation dipleg (6) and reactor body and circulation dipleg is formed.Reactor body (2) is changed into the reactor that cross section replaces convergent and flaring by original straight tube.Because the result of convergent and flaring has just formed the reactor body (2) that contraction section and expanding reach alternately exist.Fig. 2 also is an embodiment of the present utility model, the change in size scope of the cross section convergent flaring of this reactor body (2) is: the internal diameter of expanding reach and contraction section than the ratio of the intercept L between D/d=1.25～2.0, two contraction sections and contraction section inner diameter d is: L/d=2.0～4.0.The effect of contraction section is to change particle and the original movement tendency of air-flow, and the failure energy minimization process fully interacts air-flow and particle, forms even suspension; The effect of expanding reach is: because particle inertia, the expanding reach endoparticle still can keep original direction of motion, avoids contacting with wall, form an air cushion between the cylindricality zone that expanding reach wall and uniform particles distribute, no particle exists, thereby eliminates wall effect, and still keeps uniform flow field.

Among Fig. 3, ε represents the volume share that gas is shared, so 1-ε represents the shared volume share of particle, i.e. granule density.R represents the diverse location of reactor body cross section and the distance of center, at the r=0 of kernel of section place, from Fig. 3-a, find out, granule density is even substantially on the cross section of contraction section inner diameter d=52mm, on the cross section of expanding reach inside diameter D=99mm, in the scope that equals reducing area (d=52mm), granule density is also even substantially, almost not having particle on all the other cross sections exists, promptly form air cushion, particle only is that the cylindricality zone of reducing sectional area is passed through from the cross section, and is contactless with wall, therefore, eliminated wall effect.Intercept L among Fig. 3 between two contraction sections is 130mm.Can find out also that from Fig. 3-b central area and wall zone concentration difference are very not big, it is very inhomogeneous to distribute, and wall place granule density is far above the center granule density.

The utility model reactor and existing circulating bed reactor are relatively, have significant advantage and effect, because the reactor body of the utility model reactor, the reactor that adopts cross section to replace the convergent flaring replaces original straight tube reactor, and reducing place and expansion place granule density are evenly distributed, and all uniform particles is distributed in the cylindricality district that the cross section is the reducing cross section, reach the elimination wall effect, realize the purpose that uniform particles distributes, greatly improved the performance of reactor Can improve yield and the quality of product. Simultaneously, the utility model avoids using the measures such as internals, so that reactor processing is simple, easy to operate, can be widely used in the industry such as chemical industry, the energy, metallurgy and material.

Claims

1, a kind of circulating fluid bed reactor, mainly by reactor body, first order cyclone separator, forming communicating pipe of second level cyclone separator, solid particle circulation dipleg and binding reactor body and circulation dipleg, it is characterized in that the reactor body employing can produce air cushion to eliminate wall effect near wall, the cross section that forms uniform flow field is for replacing the reactor of convergent flaring.

2, according to the described circulating fluid bed reactor of claim 1, it is characterized in that the expanding reach of reactor body and contraction section internal diameter ratio are: the intercept L between D/d=1.25～2.0, two contraction sections with the ratio of contraction section inner diameter d is: L/d=2.0～4.0.