Патент USA US2409708код для вставки
0d’ 22, 1946- ' B. E. RoE‘rHELl 2,409,707 CEMENT IMHUFACTURE Filed Jan. 29, 1943 cv'cl. o NL .SEPAR Aron. Grava/Nc alu. 2 c'oN 5 Sheets-Smet 1 TA 1N‘R waAcTlON _ 32 ____I con/vayan 2,409,707 Patented Oct. 22, 1946 UNITED STATES ` PATENT OFFICE 2,409,707 CEMENT MANUFACTURE Bruno E. Roetheli, Cranford, N. J., assigner to Standard Oil Development Company, a corpo ration o! Delaware Application January 29, 1943, Serial No. 474,008 7 claims. (o1. 10e-10o) ' l This invention relates to improvements in the Fig. 3 is a partly sectional view of a multi sec manufacture of cements and relates particularly tional reaction vessel. Referring to the drawings, Fig. 1. the raw ma to improvements in the `methods of heating the compositions used in the manufacture of ce ments. , 'I‘wo processes are employed for the manufac ture of cements which are known respectively as the "wet process” and “dry process.” The wet process is the older of the two and is used almost universally in Europe while the dry process is employed to a greater extent here. The essen tial difference between the two processes is that terial consisting of the properly adjusted quan tities of calcareous materials, that is, limestone and clay materials, are introduced into grinding mills designated by the numeral I. A plurality of mills may be used and the grinding is prefer ably done dry. The mixture of raw materials is reduced to a iineness so that at least 90% will pass through a 100 mesh sieve. This finely dì vided raw material is introduced by means of pipe the limestone and the clay in the Wet process is 2, or any suitable conveying means, into a con mixed with water, ground and burned wet while tainer 3. A finely divided material is then passed in the dry process the raw materials are ground, 15 through pipe 4, provided with gate valve 5 into dried and burned. . ‘ igiepe 6 where it is conveyed to the reaction cham Formerly the burning of the mixed raw mate rials was done in intermittent upright kilns. - The `finely divided material is fluidized as it These wereV soon improved so as to economize passes to the reaction chamber 'I1 by blowing‘a r 1. , fuels by making them ` continuous in action. 20 gasthrough the finely divided material at the rate of the order of at least 0.01- to~0.05 cubic foot Where upright kilns were used, the mixture of raw materials and fuel was introduced at the top and the finished material removed from the bot tom and crushed to the desired size. Later ro tary kilns were developed which are long cylin 25 ders supported at a very slight pitch (1/2 to 3A inches to the foot) from the horizontal and are. slowly rotated as the raw materials are added. This type of kiln is generally heated by powdered per pound of powder. The gas is supplied by means of pipes 8 and 9. The fluidized ñnely di vided material behaves like a liquid and has many of the hydraulic properties of a liquid in that ' l. It flows through pipes under the inñuence of an unbalanced force such as gravity, differen tial pressures, etc. ' 2. It tends to assume the shape of the con coal but sometimes natural gases or fuel oil are 30 tainer. 3_. It flows through conduits or pipes accom used. The coal is blown in by a blast of air sup panied by a pressure drop. plied by a. fan. Commercial rotary kilns vary in 4. Gas seals can be produced in the same man» size from about 6 feet to 11 feet in diameter and ineras a liquid is used to seal a gas holder. have capacities from 200~to 2500 lbs. per day. The finishedclinker material is yground to the 35 Thereaction chamber 'I is provided with a cy clone separator IIJ in the upper part and divided desired size to impart hydraulic properties. ` In the rotary kiln process., drying, calcining oflime into three or more sections as II, I2, and I3, by means of grids I4 andv I5. The finely divided ma stone and clinkering occurs to some extent con terial in each section is in an ebullient state simi currentlyrat high temperatures with ineñicient utilization of heat owing to by-passing of large 40 lar to that of a boiling liquid. In section II it is preheated and dried `by hot gases passing up volumes of hot gases. ` wardly through grid I4. The finely ground raw One object of Athis invention is to reduce the material as it dries continuously flows over baille amount of fuel necessary to manufacturecement. I6 through outlet I'I which .is provided With- a Another object is to conduct the various stages of processing at temperatures most favorable to 45 butterfly valve I8 to a second sectionV I2 in reac tion chamber l which is likewise supplied with a each stage. baille I9 and butterfly valve20. Fuel gas is in These and other objects of the invention will be understood on reading the following descrip troduced into lower part of section I3 by means tion with reference to the accompanying _draw of pipe 2| and air is provided by means of pipe 50 22. Air is admittedthrough heater 23 and passes ings. , Fig. l is a diagrammatic plan‘ view, partly‘in up through pipe 24 to section I3 of the chamber section, representing the method‘and apparatus.' Fig. 2 is a diagrammatic plan view.l partly in section representing an alternate arrangement oi apparatus, and where the mixture of air and fuel gas burn and supply the desired temperature which may be as high as l400° C. inbrder to “clinker” the finely divided material. 2,409,707 3 i The calcined mixture from the section I2 flows over the baffle I9 into “clinkering” zone I3. The hot gases after passing through the ground mix ture in section I3 pass upwardly through grid I5 to section I2 and are used to calcine the powdered mixture in section I2. 'I'he hot gases then pass through grid I4 to section Il to dry the ground material first introduced into the reaction cham ber. To avoid high temperatures in section I I in the upper part of the chamber, cool gas, such as oxygen, CO2 or a suitable inert gas may be intro duced in section I2 by means of pipe 25, provided through pipe 6I into the second reaction vessel 55. The heated gases removed from reaction ves sel 55 may be passed to reaction vessel 4I by means of pipes 62 and 63 provided with valves 64 and 65 or through pipes 62 and 5I to the waste heat boiler 52. The clinkered material from reaction vessel 55 is removed through pipe 6I and preheat ing vessel 66 in which sensible heat from the _clinker preheats the air for combustion. A screw conveyor 66 removes the clinkered material from vessel 66 for further grinding and packaging. A fraction of the clinkered material may be with with valve 26 to cool the gases as they pass through grid I4. The “clinkered" material is re-. drawn from pipe 6I through pipe 61 provided with valve 66 and returned to the clinkering zone. Air moved from the bottom section I3 through pipe 15 is passed into pipe 61 by means of pipe 9i pro 21, through air preheater 23 and by means of vided with valve 62 where the fraction is re screw propeller 26 passes to a waste heat boiler cycled to the clinkering zone valves 93 and 94 29 where it is partially cooled and the heat used being used to regulate the ilow. 'I'he powdered to provide steam for actuating pumps, drives, material being removed through pipe 53 may air compressors, etc. Any included gases are re 20 likewise be separated into two parts. The part moved from the upper part of the waste heat removed through pipe 95 being recycled to the boiler 26 through pipe 36 which is likewise pro-Y lower section 41 of the reaction vessel 4I, air be vided with a cyclone separator or bag filter 3'I_ ing furnished through pipe 96 provided with valve to separate any solid particles. The calcined dry 61. Pipe 66, with valves 96, |66, I6I, and |62 material is then removed by means of screw con 25 being provided to regulate the air supply to reac veyor 32 from the lower part of the waste heat tion vessels. boiler 29 and passed to the grinding and packag Referring to Fig. 3, a reaction vessel is repre ing mills (not shown). ' sentedvby the numeral 16 which is provided with A portion of the clinkered material in pipe a plurality of grids 1I, 12, and 13, baifles 14 and 21 may be withdrawn through pipe 33 provided 30 15, and butterfly valves 16 and 11. Into the with valve 34, fluidized by means of air pro upper part of the reaction vessel is passed pow vided by pipe 35 and recycled through pipe 36 to dered material by means of pipe 16. The pow the clinkering section I3. Control means may be dered material is provided with sufficient gas provided on the valve 4. and the screw propeller which together with the gas arising upwardly 26 actuated by level 31 in order that the required through grid 1I is suilìcient to ñuidize and to levels in reaction chamber 1 may be automati maintain a level of 16 above the grid 1I. The cally maintained. l ' fluidized powder is heated by means of the gases Alternately, separate drying, preheating, and arising through grid 1|, dried and continuously clinkering chambers may be provided as shown passed over baille 14 through the passage formed by Fig. 2. Referring to the drawing, the powdered 40 by baille 14 and outside wall of reaction vessel raw material is introduced by means of pipe 46 into the upper part of a reaction vessel 4I which reaction vessel is provided with a grid 42 dividing the reaction vessel into two parts. An opening 43 formed by baille 44 and the outside wall of the reaction vessel 4I affords a passage between the upper section 46 and the lower section 41. The opening 43 is provided with a butterñy valve 45. - Into this reaction vessel 4I is also passed a 16 to the lower section above grid 12 where it is further heated to drive oil.’ carbon dioxide. The iiuidized powder above grid 12 as it is being heated, continuously passes through the passage formed by baille 15 and into the section above grid 13 where fuel, such as fuel oil, and air is provided through pipe 16 which on combustion, is suilicient to raise the temperature to any de sired degree. Flue gases and other reacting fuel, such as fuel oil or powdered coal, by means 50 gases may likewise be introduced into the lower of pipe 46 and oxygen or an oxygen-containing part of the reaction vessel 10 to maintain the gas such as air by means of pipe 46. The pow solid in a tluidized condition. The product in dered raw material introduced by means of pipe a clinkered state is removed through pipe 18. 46 in reaction vessel 4I is furnished with a sufll Portions of the product passing through pipe 16 cient quantity of gas to iluidize the powdered may be Withdrawn through pipes 60 and 68 and raw material and to maintain a level 56. It is ' passed through pipes 6I and 62 into which is also there dried by heat supplied by the hot gases provided gas by means of pipes 63 and 66 for rising upwardly through grid 42. 'I'he iluidized recycling clinkered solids to the desired levels dried material as it is dried, overflows baille 44 of the reaction vessel. that is, the level above grid through passage 43 to a lower section where it is 60 ‘l2 or the level above grid 13 as desired. A por still heated further to `drive oil carbon dioxide. tion of the material may likewise be withdrawn 'I'he carbon dioxide and moisture are removed as it passes through a passage such as is formed from the reaction vessel 4I by means of pipe 5I by baille 14 by means of pipe 63 and passed after passing through cyclone separator 33 and through a heat exchanger 64 and recycled to an passed to a waste heat boiler 52. The powdered 65 upper part of the reaction vessel 16 such as a material, after being heated in reaction vessel level above grid 1I. 4I, passes through pipes 53 and 54 to a second I claim: reaction vessel 56 into which fluidized powdered l. In the manufacture of cement, the im material is introduced clay or other ingredients provements which comprise reducing the lime used in preparing cement by means of pipe 56. 70 and clay materials used in the manufacture of Fuel is likewise passed through pipe 51 provided cement to a ñneness so that at least 90% will with valve 56 and pipe 36 into the reaction vessel pass thorugh a 100 mesh sieve, fiuidizing the iine 66. Oxygen or oxygen-containing gas such as powder by contacting with continuously flowing gas and progressively raising the temperature of _ air after passing through a preheater 66, passes 75 the iluidized powder by passing a heating gas in air, is likewise provided through pipe 56 which 2,409,707 countercurrent flow to said material at reduced velocity adjusted to maintain a dense turbulent body of said solid materials to iirst drive off the moisture, second the c-arbon dioxide and third, to clinker the finely divided material. 2. In the manufacture of cement, the im 5. In the manufacture of cement the improve ment which comprises continuously passing a stream of solid material comprising lime and `clay material into an enlarged reaction zone, been clinkered by the said high temperature and cement, reduced to a iineness so that at least 90%` 20 would pass through a 100 mesh sieve, through passing a heating gas, while at a temperature suñicient to convert said solid material into cement, upwardly through said enlarged zone at provements which comprise reducing ingredi reduced velocity adjusted tomaintain a dense ents used in the manufacture of cement to a turbulent body of solid material within said zone, iine powder so that at least 90% will pass through a 100 mesh sieve, blowing the fine powder con 10 maintaining said solid material in contact with said heating gas for a period of time suñicient tinuously with suflîcient gas to maintain the tine to convert said solid material into cement, with powder in a iiuid condition and progressively drawing the stream of solids from the lower por raising the temperature of the iluidized finely tion of said reaction zone and withdrawing the divided material by passing a heating gas iny countercurrent ñow to said material at reduced 15 heating gas from the upper portion of said zone. 6. In the manufacture of cement the improve velocity adjusted to maintain a dense turbulent ment which comprises continuously passing lime body of said solid materials to 1400" C., with and Vclay materials used in the manufacture of drawing the finely divided material which has grinding to a line powder. , provements which comprise grinding limestone a series of enlarged reaction zones, passing a heating gas in countercurrent ilow with said nne to a iine powder, fluidizing the limestone by ly divided material as it passes into a first reac 3. In the manufacture of cement, the im tion zone, passing a heating gas through the blowing with continuously ñowing gas, raising the temperature progressively by passing a heat 25 said reaction zones at a temperature suiiìciently ing gas in countercurrent flow to said material at reduced velocity adjusted to maintain a dense turbulent body of said solid materials to 1000° , C. to remove ñrst the-moisture and then the car high to maintain a temperature of 1400“ C. in` the last reaction zone, and 1000° C. in the first reaction zone, the said heating gas passing up wardly to the. said reaction zones in counter bon dioxide, mixing the residual fluidized powder 30 current ilow to the said material and at a re duced velocity adjusted to maintain a dense tur with clay and raising the temperature to about bulent body of solid material within said zone, 1400“ C. to clinker the ñnely divided material, maintaining said solid material in contact with separating the clinkers and grinding to a finely divided powder. ' _ 4. In the manufacture of cement, the im said heating gas for a period of time sufiicient 35 to first drive oiî the moisture, then the carbon provements which comprise grinding limestone dioxide and finally to clinker the finely divided and clay to a tine powder, blowing the finely material in the last reaction »zone where a tem perature of 1400° C. is maintained, and continu divided mixture of limestone and clay with a con ously withdrawing, in the last reaction zone, tinuously ñowìng volume of gas suiilcient to fluid ize the said mixture and progressively raising 40 cement and the heating gas from the upper part of the ñrst reaction zone. the temperature of the finely divided fluidized 7. In the manufacture of cement according mixture of limestone and clay by passing a heat to claim 6 the heating gas is contacted with . ing gas in countercurrent ñow to said material at the clinkered material being withdrawn from the reduced velocity adjusted to maintain a dense turbulent body of said solid materials to first 45 last reaction zone before passing into the last separate the moisture, second, Áthe carbon diox ide and third, to clinker the residual ñne mate rial and grinding the clinkers to a ilne powder. reaction zone. . BRUNO E. ROETHELI.