SE184846C1

SE184846C1 -

Info

Publication number: SE184846C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: B Helming och C Priissing Foreliggande uppfinning avser ett fOrfarande for forvarmning av pulverformig massa, sarskilt ramaterial for framstallning av cement, i Iva eller flera steg medelst direkt kontakt med varm gas. Man har vid exempelvis roterugnar for cementbranning, I vilka ugnar ramaterialet avldmnas vid en ingfingssida, forsokt att i sä hog grad som mojligt overfora roterugnens avgasvfirme till rfimaterialet me-deist i ugnens forvarmningsdel anordnade inbyggnader. For sadana inbyggnader har man anvant skivor, vilka bestrykes av avgaserna och uppvarmes, sfi att de vid efterfoljande inforing i rfimaterialet avgiver 'dime till ramaterialet. Vidare har man forsett ugnens forvarnmingsdel med lyftanordningar, som fort15pande inför massan i gasstr8mmen. Man liar fiven fOreslagit celliknande inbyggnader, som for forbattring av varmeavergangen uppdelar massastrommen. Sfidana inbyggnader i roterugnens inloppsfinde dr emellertid i den varma delen underkastade utomordentligt starka varmepakanningar, sfi att fiven vid anyandning av dyra varmebestandiga material inbyggnaderna fiirstores efter flagon tid, varigenom ett ekonomiskt utnyttjande ej dr molligt. Som foljd harav har sadana inbyggnader i roterugnar ej slagit igenom. Ett annat forslag har framftirts, vid vilket roterugnen forkortas och blott anyandes for efterbehandling, kalcinering, sintring, osv., medan forydrinningen sker utanfor ugnen. For fOrvarmningen har man pa senare tid borjat an-vanda cykloner, som i flera Over varandra anordnade steg astadkommer forvarmningen. Det torkade, stoftformiga materialet avgar fran den Oversta cyklonen och infOres i gasledningen for nfista cyklon och sá vidare till den nedersta cyklonen, fran vilken det forvarmda materialet infores i ugnen. Den stegliknande forvarmningen medelst cykloner har den nackdelen, att varmetransporten sker medstroms och dinigenom ej ver kar tiLhackligt intensivt. Ddrjamte dr avgastemperaturen vid en med fyra steg arbetande cyklonforvarmare alit for hog, sa att betydan, de vdrmeforluster uppkommer. Darti11 kommer, att avgasflakten naaste overvirma motstAndet i flera cykloner, varigenom kraftbehovet for avgasflaktens drivning dr mycket stort. Inventors: B Helming and C Priissing The present invention relates to a process for preheating pulverulent pulp, in particular raw material for the production of cement, in Iva or in several steps by direct contact with hot gas. Attempts have been made, for example, in rotary kilns for cement firing, in which kilns the raw material is decomposed at a finger side, to try to transfer the rotary kiln's exhaust gas company to the raw material as far as possible by means of the built-in heating elements of the kiln. Discs have been used for such installations, which are coated with the exhaust gases and heated so that, upon subsequent introduction into the raw material, they emit dime to the raw material. Furthermore, the preheating part of the furnace has been provided with lifting devices, which continue to face the mass in the gas stream. Five proposed cell-like installations have been proposed, which divide the mass stream to improve the heat transfer. However, such installations in the inlet fins of the rotary kiln in the hot part are subjected to extremely strong heat packages, so that when using expensive heat-resistant materials the installations are enlarged after a short time, whereby an economical utilization is not possible. As a result, such installations in rotary kilns have not penetrated. Another proposal has been put forward, in which the rotary kiln is shortened and only different for finishing, calcination, sintering, etc., while the pre-drying takes place outside the kiln. For the preheating, cyclones have recently begun to be used, which in several superimposed steps provide the preheating. The dried, dusty material leaves the top cyclone and is introduced into the gas line for the first cyclone and then on to the bottom cyclone, from which the preheated material is introduced into the furnace. The step-like preheating by means of cyclones has the disadvantage that the heat transport takes place downstream and thus does not act rather intensely. At the same time, the exhaust temperature of a four-stage cyclone preheater is too high, so that significantly, the heat losses occur. In this case, the exhaust gas will almost overwhelm the resistance in several cyclones, whereby the power requirement for the exhaust gas drift is very great.

Vfirme, som fitervinnes med hjalp av eyklonforvaimare, forloras darigenom Ater delvis, och i denna, i motsats till andra metoder, maste man ddrjamte rakna med en stegrad forbrukning av elektrisk strom. En ytterligare nackdel fir, att genom cyklonverkan slas ej de finaste partiklarna ned i den torkade pulverformiga massan i de olika stegen utan passerar samtliga cykloner och fOres ut I det fria med avgaserna. Trots inkoppling av de bfista anordningar for stoftavskiljning, lamnar gasernas stoftavskiljning pa grund av det for avskiljning avsedda stoftets finhet mycket ovrigt att onska. Vfirme, which is fitted with the help of eyklonforvaimare, is thereby partially lost Ater, and in this, in contrast to other methods, one must ddrjamte shave with an increased consumption of electric current. A further disadvantage is that by the action of cyclone the finest particles are not beaten down into the dried powdery mass in the various steps but pass all the cyclones and are carried out into the open with the exhaust gases. Despite the connection of the existing devices for dust separation, the dust separation of the gases leaves much to be desired due to the fineness of the dust intended for separation.

Dessa nackdelar undgas medelst forfarandet enligt uppfinningen, vilket i huvudsak kannetecknas darav, att den varma gasen i ett forsta steg ledes i medstrom med massan med en gashastighet av ungefdr 10-20 misek sá att massan medfores av gasen, varefter i ett andra och ytterligare steg den varma gasen, sedan den skilts fran massan i det for sta steget, ledes med en hastighet av ungefar in/sek i motstrom och/eller tyfirstrom genom massan, vilken ledes till det forsta steget och fardigf8rvarmes -dfir. These disadvantages are avoided by means of the process according to the invention, which is mainly characterized by the fact that the hot gas in a first stage is passed in co-current with the mass at a gas velocity of about 10-20 degrees so that the mass is carried by the gas, then in a second and further step the hot gas, after being separated from the pulp in the first stage, is passed at a rate of about in / sec in countercurrent and / or tyfir stream through the pulp, which is passed to the first stage and preheated.

En for forfarandets utforande ldroplig anordning kannetecknas i huvudsak av en eyklon, an:ordnad att mottaga en blandning av varm gas och pulverformig massa Och att avgiva i huvudsak enbart den varma gasen till en eller flera 1 serie med varandra -forbundna kamrar av stor rymd; -vilka fir f8rsedda med pneumatiska eller mekaniska me- del f Or slungning av pulverformig massa i. gas- 2--- -, -- striimmen, varvid anordningerx ãr sa.dan, att den varma gasen ledes genom kamrarna i motstriim och/eller tvarstrom i fiirhallande till massan, -och att massan, sedan den passerat genom kamrarna, ledes till cyklonen i form av ovannamnda blandning och uttages darifran som fardigforvarmd massa. Forvarmningen av det pulverformiga materialet sker salunda Oven i detta fall stegvis. I det. Tarmaste temperaturomradet ager varmeutbytet rum vid hog gashastighet med gasen ledd i inedstrom med massan i en cyklon. Den varma gasen, som i det fiirsta steget kommer i beroring med massan med en hastighet av ungefar 10-20 m/sek, far i detta steg yidkannas ett temperaturfall fran 1000° C till 600-700° C. I nasta steg koinmer den varma gasen i beroring med massan med ringa hastighet, ungefar 0,3-3 m/sek. Forvarmningen I sistnamnda steg sker i kammaren eller kanirarna med stor rymd. Den varma gasen far i detta steg vidkannas en temperaturminskning av ungefar 200-300° C. I ett ytterligare steg sker darpa den ytterligare forvarmningen i mot- eller tvarstrOm, sh att den varma gasen nastan fullstandigt avgiver sin varme till mas.san. Den varma gasen, Tars stoftinnehall normalt, kan medelst kanda hogeffektiva 'stoftavskiljningsanordningar renas i sadan grad, att i gasen kvarvarande stoft är det foreskriftsenligt tillatna. Som forvarmare med stor rymd kan en cylindrisk halkropp anvd.ndas, vilken: i likhet med en roterugn langsamt vrider sig pa rullar. Denim trumma kan vara fOrsedd med celler, ror eller lyftelement, sa att den pulverformiga massan kommer i intim beroring med den varma gasen, som ledes i motstrom ochleller tvarstrom genom massan, varigenom ett intensivt varmeutbyte ager Eftersom cyklonen skyddar forvarmaren mot for hoga temperaturer, utsdttes anordningarna (r8r, celler osv.) i trumman ej f8r hoga temperaturer och skyddas darigenom mot forstoring. Eftersom aven den varma gasen strommar in i motstroms- och/eller tvarstromsforvarmaren med lag temperatur, kan for inbyggitaderna anvandas billiga material, vilkas langa livslangd ph detta sat sakerstalles. A dropping device for carrying out the process can be characterized essentially by an eyclone, arranged to receive a mixture of hot gas and powdered mass and to discharge substantially only the hot gas to one or more series of interconnected chambers of large space; which are provided with pneumatic or mechanical means for throwing powdery mass into the gas stream, the devices being such that the hot gas is passed through the chambers in the opposite stream and / or transverse current in relation to the pulp, and that the pulp, after it has passed through the chambers, is led to the cyclone in the form of the above-mentioned mixture and is taken therefrom as a preheated pulp. The preheating of the powdered material thus takes place in this case stepwise. In it. The intestinal temperature range acts as the heat exchange space at high gas velocity with the gas led downstream with the mass in a cyclone. The hot gas, which in the first step comes into contact with the mass at a speed of about 10-20 m / sec, in this step a temperature drop from 1000 ° C to 600-700 ° C is detected. In the next step, the hot the gas in contact with the mass at low speed, approximately 0.3-3 m / sec. The preheating In the latter step takes place in the chamber or canaries with large space. In this step, the hot gas is subjected to a temperature reduction of approximately 200-300 ° C. The hot gas, Tars dust content normally, can be purified by means of known highly efficient dust separation devices to such an extent that the dust remaining in the gas is properly permitted. As a preheater with a large space, a cylindrical sliding body can be used, which: like a rotary kiln slowly rotates on rollers. Denim drum can be provided with cells, tubes or lifting elements, so that the powdery mass comes into intimate contact with the hot gas, which is led in countercurrent and / or transverse flow through the mass, whereby an intensive heat exchange acts. the devices (tubes, cells, etc.) in the drum are not for high temperatures and are thus protected against magnification. Since the hot gas also flows into the low-temperature countercurrent and / or cross-flow preheater, cheap materials can be used for the built-in units, the long service life of which is at stake.

Uppfinningens grundtanke är alltsa den, att varmentbytet I mycket hoga temperaturomraden sker vid hog hastighet pa. avgaserna i cykloner, medan den i Iaga temperaturomraden sker vid lag avgashastighet i storrymdskammare av kant utforande. The basic idea of the invention is therefore that the heat exchange in very high temperature ranges takes place at high speed. the exhaust gases in cyclones, while in the Iaga temperature ranges it occurs at low exhaust gas velocity in large-space chambers of edge design.

Uppfinningen skall beskrivas i det foljande under hanvisning till bifogade ritning, ph vilken tvâ utforingsexempeI ph anordningar for utlivning a-v uppfinningen Or schematiskt visade. Fig. 1 visar en anordning med tvh forvarmningssteg. Fig. 2 visar en anordning, vars forvarmningssteg bildas av en vridbar trumma. The invention will be described in the following with reference to the accompanying drawing, in which two embodiments of devices for embodiment of the invention are schematically shown. Fig. 1 shows a device with two preheating steps. Fig. 2 shows a device, the preheating stage of which is formed by a rotatable drum.

En. roterugn 1 ar utf8rd och lagrad p4 kOnt satt. In i ugnen mynnar ena Auden av en brant stigande, isolera.d rorledning 2, som leder till en med isolerade vaggar forsedd cyklon 3, vilken har ett utloppsr8r, som i det narmaste nar ned till roterugnens 1 botten. Ett r5r 4 forbinder cyklonen med en kammare av stor rymd bildande forvarmare 5, vilken forvarmare 5 medelst ett ror 6 är forbunden med en ovanfor derma anordnad, en kammare med stor rymd bildande forvarmare 7. Till denna fOrvarmare 7 Or ett ror 8 anslutet, som leder till en lake visad stoftavskilj are. Var och en av forvarmarna 5 och 7 Or forsedd med en hastigt roterande, i och for sig kand omroringsanordning 9, som standigt slungar den pulverformiga massan in i avgasstr8mmen. Var och en av forvarmarna 5 och 7 har vid sina framre andar ett utlopp 10, under vilket en snacka 11 Or anordnad. Snackornas 11 utlopsande 12 mynnar i forvarmaren 5 resp. rorledningen 2. I rorledningen. 2 Or en halvklotformig skyddsvagg 13 anbragt framfor utloppsandens 12 mynning, vilken vagg 13 har till andamal, att forhindra intrangande av vanm. gas i snackan 11. Ramaterial tillfores anordningen genom en vid forvarmaren 7 anordnad, med en sluss forsedd tratt 14. I stallet for de hada forvarmarna 5 och 7 kan Oven en enda motsvarande dimensionerad forvarmare vara anordnad. One. rotary kiln 1 is made and stored p4 kOnt sat. Into the furnace one Auden opens from a steeply rising, insulated pipe 2, which leads to a cyclone 3 provided with insulated rocks, which has an outlet pipe, which almost reaches down to the bottom of the rotary furnace 1. A tube 4 connects the cyclone to a chamber of large space forming preheater 5, which preheater 5 is connected by means of a tube 6 to a chamber arranged above it, a chamber of large space forming preheater 7. To this preheater 7 is a tube 8 connected, which leads to a lake shown dust separator. Each of the preheaters 5 and 7 Or is provided with a rapidly rotating, per se known stirring device 9, which constantly throws the powdery mass into the exhaust stream. Each of the preheaters 5 and 7 has at its front breaths an outlet 10, under which a talc 11 Or is arranged. The outlet 12 of the snacks 11 opens into the preheater 5 resp. pipeline 2. In the pipeline. 2 Or a hemispherical protective cradle 13 arranged in front of the mouth of the outlet sand 12, which cradle 13 has the purpose of preventing intrusion of water. gas in the snack 11. Raw material is supplied to the device through a funnel 14 arranged at the preheater 7, with a funnel 14 provided with a lock.

Anordningen enligt fig. 2 har en lutande, vridbar trumma 15, vars inre bestar av flera bredvid varandra anordnade ror 16. Vid trummans inlopps- och utloppsandar Or samlare 17 anordnade, av vilka den vid inloppet befintliga samlaren Or avsedd att fordela den fran tratten 14 genom slussen i samlaren 17 inforda massan till de olika roren 16. En till trummans utloppsande ansluten glidbana med sluss 18 leder massan in i avgasledningen 2, vilken nar in i cyklonen 3. The device according to Fig. 2 has an inclined, rotatable drum 15, the interior of which consists of several tubes 16 arranged next to each other. Collectors 17 are arranged at the inlet and outlet ends of the drum, of which the collector through the lock in the collector 17 introduce the mass to the various tubes 16. A sliding path connected to the outlet of the drum with lock 18 leads the mass into the exhaust line 2, which enters the cyclone 3.

Verkningssatt. Avgasen lamnar den fOr slutkalcinering resp. sintring avsedda roterugnen 1 med en temperatur av ungefar 1000° C och str8mmar genom den brant stigande ledningen 2 till cyklonen 3, varvid avgasen medbringar det pulverformiga material, som lamnar roret 12. Under stromningen till cyklonen 3 avgiver avgasen en del av sin varme till materialet, vilket genom cyklonens utloppsror le-des till roterugnens botten. Med en temperatur av ungefar 600-700 C strommar avgasen in i den f6rsta fEirvarmaren. 5, i vilken omroringsanordningen. 9 sorjer for att massan le-des i motstridna resp. tvarstrom med den varma gasen, varvid gasen avgiver en betydande del av sin varme. Med en temperatur av ungefar 200-300° C strommar gasen darpa genom roret 6 in i den andra, hogre liggande forvarmaren 7, i vilken gasen avgiver ytterligare en del av sin varme pa samma salt som i den f6rsta forvarmaren. Avgasen lamnar den andra forvarmaren genom roret 8 och strommar — —3 in i stoftavskiljningsanordningen och avgar fran denna till det fria. Effective. The exhaust gas leaves it for final calcination resp. sintering for the rotary kiln 1 at a temperature of about 1000 ° C and flows through the steeply rising line 2 to the cyclone 3, the exhaust gas carrying the powdery material which leaves the tube 12. During the flow to the cyclone 3 the exhaust gas gives off some of its heat to the material , which is led through the outlet pipes of the cyclone to the bottom of the rotary kiln. With a temperature of about 600-700 C, the exhaust gas flows into the first furnace heater. 5, in which the stirring device. 9 ensures that the mass is led in conflicting resp. transverse current with the hot gas, the gas emitting a significant part of its heat. At a temperature of about 200-300 ° C, the gas then flows through the tube 6 into the second, higher-lying preheater 7, in which the gas gives off a further part of its heat on the same salt as in the first preheater. The exhaust gas leaves the second preheater through the tube 8 and flows into the dust separation device and exits from it into the open air.

Anordningen enligt fig. 2 arbetar ph samma satt som anordningen enligt fig. 1 dvs. den varma gasen avgar fran roterugnen 1 och strommar genom rorledningen 2 till cyklonen 3, dhr gasens temperatur kraftigt sankes genom berOringen med det genom slussen 18 inforda pulvret. Pet i cyklonen 3 avsldlda pulvret fares till ugnsbottnen medelst eyklonens utloppsror. Den varma gasen ledes genom rOret 4 in i ror- och trumforvarmaren 15, i vilken gasen kommer i intim berking med massan och avgiver ytterligare en del av sin varme till denna. Den ph trummans 15 inloppssida anordnade samlaren 17 fordelar frau tratten 14 genom slussen tillford massa likformigt till de olika roren 16, sa att garanti Ar forhanden, att massan likformigt uppydrmes. The device according to Fig. 2 operates in the same way as the device according to Fig. 1, i.e. the hot gas emits from the rotary kiln 1 and flows through the pipeline 2 to the cyclone 3, where the temperature of the gas is greatly reduced by contact with the powder introduced through the lock 18. The powder sold in the cyclone 3 is carried to the bottom of the oven by means of the outlet pipes of the eyclon. The hot gas is led through the tube 4 into the tube and drum preheater 15, in which the gas enters into intimate berking with the mass and gives off a further part of its heat to it. The collector 17 arranged on the inlet side of the ph drum 15 distributes the pulp 14 through the sluice supplying pulp uniformly to the various tubes 16, so that there is a guarantee that the pulp is uniformly heated.

Fran forvarmaren 15 strommar avgasen pA kant satt till en. stoftavskiljare och avledes fran denna till fria luften. Det avskilda stoftet hterfOres till ugnen pa. lampligt shit. From the preheater 15 flows the exhaust gas on the edge set to one. dust separator and diverted from it to the open air. The separated dust is returned to the oven on. light shit.

Claims

Patent claim:

Process for preheating pulverulent pulp, in particular raw material for the production of cement, in two or more stages by direct contact with hot gas, characterized in that the hot gas in a first stage is conducted in cocurrent with the pulp at a gas velocity of about 10 -20 misek sh, that the mass is entrained by the gas, after which in a second and further step the hot gas, then the hot gas, then the skills from the mass in the first step, is led with a gas velocity of about 0.3-3 misek in countercurrent and / or transverse current through pulp, which is led to the first stage and ready-heated ddr.

Device for carrying out the method specified in patent claim 1, characterized by a cyclone (3), arranged to receive a mixture of hot gas and powdered mass and to deliver substantially only the hot gas to one or more interconnected series chambers of large space, which are provided with pneumatic or mechanical means (9) for throwing powdered mass into the gas stream, the device being such that the hot gas is passed through the chambers in countercurrent and / or transverse flow in relation to the mass, and that the mass , after passing through the chambers, is led to the cyclone (3) in the form of the above-mentioned mixture and is taken therefrom as a preheated mass.

Device according to claim 2, characterized in that the chambers are formed by a rotatably mounted drum (15).

Device according to claim 3, characterized in that the drum (15) contains adjacent tubes (16) lying next to each other in the longitudinal direction of the drum.

Device according to claim 3 or 4, characterized in that the drum (15) on the inlet side is provided with distributor devices. Request publications: