CZ815386A3 - Method of carrying out reactions under high temperatures - Google Patents

Abstract

1. Process for carrying out high-temperature reactions between hot gas and previously heated solids, which during the high-temperature treatment lose their ability to flow freely, in a substantially vertical conveyor passage with subsequent cooling and separation from gas, characterized in that the heated solids are supplied from below and in the direction of conveyance trough a burner flame located in the lower region of the conveyor passage (17), they are caused to pass through a sufficiently long reaction zone and after the reaction has been completed they are coded to at least the temperature at which the ability to flow freely is achieved with an unchanged direction of flow by the separate addition of cooling agent downstream in the direction of flow.

Description

The invention relates to a process for carrying out high temperature reactions between hot gas and preheated solids which lose their flowability in a high temperature treatment in a substantially vertical conveying path with subsequent cooling and separation from the gas.

In high temperature reactions, the solids react to temperatures that are above the temperatures at which the solids lose their flowability. The individual particles agglomerate, stick together or adhere to each other and / or form deposits on the inner walls of the reactor or the tubing. The cause / loss of flowability may be due to the reaction of the solid fusion gas with other components. The aforementioned problems can arise in the burning or sintering of, for example, alumina, limestone, dolomite, magnesite and cement.

There are known methods and apparatuses which are intended to solve these process-technical difficulties.

'^; * 1 · Ά ll · 1 · ^Λ -, *] >> - ') W.

_ · Ι-Ζ - * - k-t-t. ~. a-L

j.nc zprseovíini ^ o ^ o ^ imne / Lo mateři.-Λ -. ;; pccu. ·· s

><- / 4, _'w -A-pzsac invaei ancu ^, ^ .I cj.n CNI / in.

through the sintering zone and the cooling zone, at least one portion of the calcined material is subjected to a separate portion prior to entering the sintering grain; heat treatment to drain the melt-phase components. This state of the art is naturally applicable only in those cases in which the wetting capability of the components forming the melt phase is achievable. In other cases, it cannot be ruled out that, when sintered in the suspension zone, in the reaction zone, the reaction mixture is exothermic.

Z- ui 1 ·. 4 «θ 7 ',' · <; H 'h -' IS. *>. 1 * P. / r. - '' »i7 · '· * ^Λ - · - * (_ ,. · * - *' - - '' -! _»> J w '<+

The temperature between the hot gas and the pre-heated gas, which did not have the known disadvantages mentioned above, would allow trouble-free conducting of the reaction and which would be universal and simple to carry out.

guided in accordance with the invention for carrying out high temperature reactions with solids which lose their flowability at high temperature treatment at rc;

. . - - .- _ ·· -. -χ -r y. / * ·· .. * · - ·, * '* 7-' j j _r '* »· ♦ o ~„ ... iL · - * k, - - iL · —J í t. The heating of the heated solid bath is subjected to high-temperature hot gas in a substantially vertical conveying path and finally cooled and separated from the gas by introducing the preheated solid from below downstream of the burner flame. located in the lower part of the conveying path, it is passed through a sufficiently long reaction zone and, after completion of the reaction with an unchanged flow direction, the flow of cooling agent added is cooled downwards in the flow direction.

at least to the temperature at which they heat in the circulating fluidized bed to which the oxygen-containing fluidizing gas is fed and the secondary manifestation is 1 1 ·. q - .- · and. - ά

Oxygen-containing oxygen. Preferably, the solid starting material is a solid starting material

• i; znu :: kiocravni c; ra /: v

The solid separated from the reaction of the gas is preferably additionally cooled in a fluidized bed cooler to be additionally cooled by heat exchange with an oxygen-containing gas which, upon its aging, becomes more dull and hardened by the formation of xuocas and / or or a high temperature solid reaction.

It is preferably used to heat the solid starting material / in the circulating fluidized bed

- ro> P? > i -ΐ n »0. τ-λ -f rj vn *> Ί '♦ r- r *> Π £ i C' tf ¹ f 2 Ί ^Ω 'Ύί ¹ ' ¹ 7 '

Ca · *. The heat exchanger is heated in a fluidized bed cooler, and the oxygen-containing secondary gas is a waste gas from the conveyor track.

Advantages of the process according to the invention are that by introducing the solids from below and in the direction of flow as well as by the addition of coolant with unchanged flow direction, the gas / solid suspension passes through the critical reaction phase between heating to high temperature and cooling to high temperature. temperature, α7 0-4.

4470 0 ^ 44.0704 444-74 .. _0 L without bending 2 shades beu note

J40 0 04X. ' gas / py <? 3tI t07b 40300.-117 inuavton cniamcmo oroumeum ni enan-no; avit oouaded in high teolotš times yes couaaav ..- ·. ´.

τννπ p-.

4044 In the legal arauc jo trcoa set soy 4o doaanovaio high relative velocity 010ui fixed with fabric and wall, it is usually medium rvcklout yawn 7 distributes 2 au 11 ~. / S \ y e - v * (44 47 .410 « 'f · »'> T, -t - ¹ T y · ··· 1 ΤΙ'- 'ΛΓι o'

U - tX ¹ * ab 7 £, - bx 4>. > 7 · L '_ y "(i ^ p ^ ¹ _ VC i.e. 1" / 3 * 7 I O J X B into the conveying path is suitably in torsos slurry gas / povna x; u:

-Λ- '> Ί ·: 7 center krzhovitenc noraku that works on · o-ynen -ano oaiivoii.

-ί ';' i '' V hit p ~ .'JPci L b. iZ t C '' - ~ h temperature. This temperature is depending on the material and the desired results at a temperature of 1 ° C, preferably 14 ° C to 4 ° C.

0.0441741341 1;

The length of the conveyor line ae depends on the delay time, depending on the type of reaction advised. In just a few seconds, the length of the conveyor line is 2 m, generally 9 [mu] m. "Asen" rubbed after rcance or; It can be used with gaseous, liquid or solid chilling agents. Their addition may be such that rapid mixing of the 3n gas suspension with the solids is obtained.

It is generally advisable to add at tangential velocity to the grass path at an angle up to an angle up to the direction of flow.

* X in It b th un n high for the shade axis critical. J zení zení už na na náv na náv náv náv náv na náv náv náv náv náv náv náv náv náv náv náv náv The heating, which is generally also associated with the cnemic reaction, in the so-called circulating fluidized bed appears to be particularly advantageous.

In contrast to the conventional fluidized bed, the fluidized bed is characterized in that the concentrated phase is separated from the gas space located above it by a considerable density gradient in that the states of separation occur without a defined boundary layer. There is no density gradient between the concentrated phase and the dust space above it. In the reactor, the solid phase concentration is continuously reduced to the top. For details on the operation of the circulating fluidized bed, reference is made to the publication

L. Reth et al. , / irbeischichtpr or gsso e- v r on Cnemj

..utteninuustne. ure Zner .leuuwanuuunj unu den Lntsckutz, Che ~. Znj. leehn. oř (ui?; as-ΰ i on ZZ-Pd no.

The advantage of the circulating fluidized bed lies in the high throughput at the reactor cross-section and in the tenderness of setting the docking delay of the heated flat material so high that the chemical reaction associated with the heating is virtually complete. In the process of applying the present invention, only a single high-temperature heat exchanger reaction then takes place.

.... Jx '7' d-1 ', ¹ ' f nl n at nu ^ ur resron level.

After the solids leaving the conveying path have separated, further cooling is normally intersected. This is also done by the conventional cooling devices known in the prior art, but particularly those with fluidized bed cooling.

A preferred embodiment of the process according to the invention consists in this

VySoUOteCXOt:

ZOr aCOVun

The heating of the solid and the subsequent cooling of the fedpia integrates as the individual gas streams may find alternating use. For example, the hydrogen gas used in the heating and / or high temperature treatment step can be preheated in the cooler. Furthermore, ³ of the example 2 transport offgas used in plucking zone of ahří wing.

The optimum conduction of the overall process consists in heating the material to be processed in a circulating fluidized bed which is equipped with a pre-heater operating with the exhaust gas, and the subsequent cooling takes place in a fluidized bed chiller with a plurality of cooling chambers flowing through each other. The solids can be cooled directly and / or indirectly with oxygen-containing gases which can then be fed into the conveying path as a carrier gas and / or into the circulating fluidized bed as a diluent gas. Piu: the di- gassing gases used in the 3θ vortex cooler can finally be used in the conveying path as a cooling medium, the exhaust gases from the conveying paths in the circulating vortex layer as secondary pJyi.

The present invention is illustrated in more detail with reference to the figure and the following example.

'/ * s->t' l Λ 'Ϊ' 1 ^Λ Τ Z 'w *. 1? m ·. -* 'ení ení ζ ení ení ení ení ζ ení ení ení ení ení ení ení ení

j s

The material to be processed is fed through the dispensing device 1 to the last ventilator. When the gas is heated and heated in the cyclic emitter, it is fed through the conveying device 4 to another preheating system consisting of a second venturi exchanger 5 with a second cyclone separator 6 and a third venturi exchanger 7 with separator Z.

‘Aí, kl yylons;

From the third cyclone separator δ, the solid is fed to a circulation system consisting of a fluidized-bed reactor IC, a return cyclone 11 and a return line 12. The fluidized bed reactor 16 is supplied with fuel 15, fluidized gas line 14, and line 15 with fuel line 15. secondary throttle ₀

After a sufficiently long residence time, the heated material is fed via line 16 to the lower region of the conveyor track 17 and is introduced into the flame of a burner in which fuel supplied by line 15 and oxygen gas (line 19) are combusted. During the forward movement of the slurry of gas and solid in the lower part of the conveyor path 17, the reaction takes place at a high temperature, after which it is cooled by means of the gas supplied via line 20. After sufficient cooling in the unchanged flow direction, the solid and gas slurry is discharged through the discharge conduit 21 and distributed in the cyclone separator 22. The solid is fed to the fluidized bed cooler 23 and the separated gas is passed as secondary gas to the fluidized bed reactor 10 as a secondary gas.

The fluidized bed cooler 25 is divided into a plurality of successive chambers flowing through said solid and has a total of three cooling compartments. Downstream of the solids in the first hottest compartment, the oxygen-containing gas is heated and then discharged via line 19 to the conveyor path 1 in the bottom compartment to heat the oxygen-containing hiolyne supplied via line 14 to the fluidized bed reactor 10. In the third cooling compartment, the solids are finally cooled with cooling water which is fed through line 24 and discharged through line 25. The cooled product is discharged through a discharge device 26. medium to conveyor track 17.

Example

It is necessary to convert the moist aluminum hydroxide after filtration to highly calcined alumina.

An aluminum hydroxide having a moisture content of 12% by weight and a temperature of 60 ° C is supplied in an amount of 8.69 tonnes per hour via the metering device 1 to the venturi exchanger 2. By exchanging heat with the gases discharged from the second cyclone separator 6 having a temperature of 390 ° C, the aluminum hydroxide is heated to 160 ° C, said gases being cooled to about the same temperature.

By means of a conveying device, the preheated aluminum hydroxide is contacted in the second venturi exchanger 5 with the exhaust gases from the third cyclone separator 8 having a temperature of 510 ° C. This involves heating the solid to 390 ° C and cooling the gas to the same temperature. After separation of the gas and solids in the second cyclone separator 6, the solids are introduced into a third venturi exchanger 7 where they are mixed with the waste gases at a temperature of 1150 ° C from the circulating fluidized bed. Perfect mixing results in a gas / solid suspension of 510 ° C. After further separation of the gas and solid in the third cyclone separator 8, the solid is fed to the circulating fluidized bed.

To the fluidized bed reactor 10 forming the circulating fluidized bed, 2000 Nm @ 2 per hour of 560 ° C fluidization air (originating from the second compartment of the fluidized bed cooler 25) was fed through line 14, and 4600 Νητ per hour of secondary was fed through line 15. air at 1020 ° C (from a cyclone separator)

and from the fuel line 15, 550 Dr / hr of natural gas is supplied. In this way, a temperature of 1150 ° C is achieved, which is practically constant throughout the circulation system consisting of the fluidized bed reactor 10, the return cyclone 11 and the return line 12.

After a mean residence time of about 20 minutes, during which the alumina is completely calcined, the corresponding amount of solids is fed via line 16 to the conveyor path 17 and is heated to a temperature of 7 using the burner flame or the flue gas from the burner.

14 ° C. the burner is supplied with 110 · No? and an air temperature of 650 ° C (originating from the first fluidized bed chiller 2).

After about four seconds, the reaction was complete with high temperature. By introducing 5500 sheets per hour of air at 470 ° C (coming from the second compartment of the fluidized bed cooler 25), the gas and solid slurry are cooled. Thus, the suspension is cooled to &gt; 1020 DEG C. at which sufficient solids flow is ensured. The gas and solids slurry is then distributed in a cyclone separator, and the gas at 4300 Nn / hr is removed as secondary gas to reactor 10;

The fabric is discharged to the cooler by the fluidized bed and fluidized bed.

In the fluidized bed cooler 25, the solid is cooled in several compartments to a final temperature of 30 ° C.

For this purpose, considered in the direction of flow of the solid, in the first step, it is heated by

12Ir? for air debris, increasedEXa and heat ° 1, in the second compartment 2C? 0? per hour air, zskssi & xxs and in the third compartment heats from 55 ° C to é

sahríva temperature o 30 20 X with an hour of water that se z Οχ, on · The gaseous streams are how was

previously mentioned, going back into the process.

The production in this process is pt per hour of alumina with a 3PT surface

Bye .

? / s ap pATfMroVE

Claims (1)

Claims 1.  C 1 Cr; enjoyment of high temperature reaction with 3 solids, which are processed by the steeds; the eplotts soak their shine, during which the warm laymen first heat up, then after it gets rid of it, X í 4>;, and L ‘J active substances U. - / T mhhíplmív; ··. · F; , · - »-v, ^f . T ¹ ΛΟΓΖγΣΙ p lynem ve v submap vertical traffic m á? 3 finally cools and cddí from gas, v y z n v. / a 0 u p 1 c í se k <im, * .e se prelude- m fixed. grandchildren in cmccuu in my stream through the celebration of the burner, not letting the church sleep at the bottom; eight paths, allow to pass long enough reaction hay and after the reaction at unchanged flow direction continue downstream by coolant addition cool at least to a temperature at which flow is achieved. cucking weerolts> The process according to claim 1, characterized in that the solid starting materials are heated in a circulating fluidized bed, which is supplied with an oxygen-containing fluidizing gas: an oxygen-containing secondary gas, up to 100 ° C. The starting material is heated with the coarse odors of the conveying path. VUWoUuÍ The method of items 1-3, further away from the gas, is additionally cooled in a fluidized bed cooler. rizU-oLti The method according to claims 1 to 5, wherein the opener is additionally cooled by heat exchange with oxygen-containing gases, which after being heated are introduced into the heating stage of the solid starting material and / or the high-temperature solid reaction. The method according to claims 1 to 5, characterized in that the heating of the solid starting material is used as a fluidizing means, wherein an oxygen-containing gas is used for the circulating fluidized bed. Λ ΌΓΟνΓ.Ι Ο J. Γ7,. -L ύ ι; υ;