秸稈成型機烘干系統(tǒng)及部件設計

秸稈成型機烘干系統(tǒng)及部件設計,秸稈,成型,烘干,系統(tǒng),部件,設計 Overall and structural design of rotary dryer1 IntroductionThe drying operation involves almost all sectors of the national economy and iswidely used in production and life. The so-called dry is generally from solid materialsmake the evaporation and separation of a liquid (usually water) operation, includingfrom the evaporation of the liquid or slurry material to remove moisture, in order toachieve solid in the loss of moisture. The purpose is to remove some of the rawmaterials, semi-finished and finished products in the water or solvent, in order tofacilitate the processing, use, transport, storage, etc.Drying is a great deal of heat consumption, today in the strict demands on energysaving and heat source for drying, if the heat source of cheap gas and residual steamas the direction, the dryer itself, even with reduced thermal efficiency, but on thewhole, the economy is still. In addition, before entering the drying process, the formertreatment process can be used to reduce the water method is economical.For dry operation, the choice of the dryer is a very difficult and complicatedproblem. Due to the characteristics of dry materials, heating methods and materials -the fluid dynamics of the system must be fully considered. Due to the variety of drymaterials, different requirements, it is impossible to have a universal dryer, can onlychoose the best drying method and dryer form.The main body of the rotary dryer is a cylinder which is slightly inclined and canrotate. Wet material from the upper part of the left join, through the inner cylinder,and through the inner cylinder hot air or heated wall surface of effective contact isdried, dried products from the lower part of the right end of the collection. During thedrying process, the material is rotated slowly by the aid of the cylinder, moving fromthe higher end to the lower end under the action of gravity. The inner wall of thecylinder body is provided with a parallel plate (or similar device), which continuouslythrows the material from the surface of the thermal contact surface of the material toincrease, in order to improve the drying rate and promote the material moving forward.The heat carrier used in the drying process is generally air, flue gas or water vapor,etc. If the heat carrier, such as hot air and flue gas directly in contact with thematerial, after drying, usually with cyclone separator in gas entrained fine grainedmaterial capture set down, non air is after Cyclone vent. Rotary dryer is one of theoldest drying equipment, but it is still widely used in metallurgy, building materials,chemical industry and so on because of the high efficiency and the high efficiency ofeconomic and practical work.2 Overview2.1 the purpose of dryingThe drying operation involves almost all sectors of the national economy and iswidely used in production and life.The so-called dry is generally from solid materials makes the operation ofevaporation and separation of a liquid (usually water), including from the evaporationof the liquid or slurry material to remove moisture, in order to achieve solid in the lossof moisture. The purpose is to remove some of the raw materials, semi-finished andfinished products in the water or solvent, in order to facilitate the processing, use,transport, storage, etc.Drying is a great deal of heat consumption, today in the strict demands on energysaving and heat source for drying, if the heat source of cheap gas and residual steamas the direction, the dryer itself, even with reduced thermal efficiency, but on thewhole, the economy is still.In addition, before entering the drying process, the former treatment process canbe used to reduce the water method is economical.2.2 Main composition and function of rotary dryerRotary dryer is mainly composed of the following main parts. The cylinder is amain part, need in reaction or operation space determines the overall size. Thecartridge is empty or has a copy board, and also has a chain, to achieve the purpose ofincreasing heat transfer and crushing material.Arolling ring is arranged on the cylinder, the weight of the material in the barrelbody and the barrel is passed to the supporting wheel of the supporting seat throughthe rolling ring. Agear ring is arranged on the cylinder body of a block wheel seatnear the support wheel. Gear mounted on the shaft of the reduction gear box isconnected with the gear ring, and the gear box and the motor form a transmissionmechanism.In the end of the drum material, is provided with a chamber for unloading ofmaterials and incoming or the introduction of gas extraction. The outlet end of thecylinder is sealed with a sealing device (a labyrinth or an end face seal).At one end of the cylinder is provided with a discharging device, which is usedfor loading and unloading the processed solid material.The processed material and the air flow can flow in the rotating drum, and canalso be counter current. If due to processes or reactions of must be heated, the heatcan be directly offered by gas; also can be introduced by the cylinder wall; due to thecylinder of the material being handled by the release of heat of reaction; also by incylinder direct fuel supply. The method of gas heating and the maximum temperatureare determined by the properties of the solid material and the factors such as whetherit is allowed to be dirty and so on.It is usually made of circular cross section in terms of manufacturingconvenience, high mechanical strength and low material consumption. But a smallrotating cylinder, there are also made of hexagonal or polygonal, and even some ofthe ends of the cone made of.The size of the contour of the cylinder decided to the required productioncapacity, the material in the barrel stay time and through the maximum cylinder gas toallow the speed.2.3 rotary drum dryer working principleThe main body of the rotary dryer is a cylinder which is slightly inclined and canrotate. Wet material from the upper part of the left join, through the inner cylinder,and through the inner cylinder hot air or heated wall surface of effective contact isdried, dried products from the lower part of the right end of the collection. During thedrying process, the material is rotated slowly by the aid of the cylinder, moving fromthe higher end to the lower end under the action of gravity. The inner wall of thecylinder body is provided with a parallel plate (or a similar device), whichcontinuously throws the material from the surface of the thermal contact surface ofthe material to increase, so as to improve the drying rate and cause the material tomove forward. The heat carrier used in the drying process is generally air, flue gas orwater vapor, etc. If the heat carrier, such as hot air and flue gas directly in contactwith the material, after drying, usually with cyclone separator in gas entrained finegrained material capture set down, non air is after Cyclone vent. Rotary dryer is oneof the oldest drying equipment, but it is still widely used in metallurgy, buildingmaterials, chemical industry and so on because of its great economic and practicalwork.2.4Classification and application scope of drum dryer2.4.1 direct heating(1) conventional direct heating rotary dryerThe material in the drying device is directly contacted with the hot air in thedrying process, and the drying process is carried out by the method of convective heattransfer.According to the flow direction between the hot air and the material, the flowdirection is divided into parallel flow and counter flow. The hot air and the materialmoving direction are the same in the flow type, and the hot air with high temperatureat the entrance is in contact with the material with high moisture content. Because thetemperature of material is in the stage of surface vaporization, the temperature of theproduct can still keep the wet bulb temperature. Although the temperature at the outletside of the material increases, but at this time the hot air temperature has been reduced,so the temperature of the product will not be too large, so the choice of higher hot airinlet temperature, will not affect the quality of the product. For the heat sensitivematerial drying including those contains easy volatile material drying is very suitablefor; for high temperature materials using counterflow drying, heat utilization rate ishigh. The air outlet temperature of the dryer is generally higher than that of thematerial outlet temperature of 10, 20. In the counter flow type, if not clearly defined,the general use of 100 degrees as the temperature of the outlet is more reasonable.The diameter of the cylinder is generally 0.4 - 3M, and the ratio of the length tothe diameter of the cylinder is 4 - 10 -. The circumferential velocity of the dryer is 0.40.6m/s, the air velocity is in the range of 1.5 - 2.5m/s.(2) vane type wear circulation tube dryerIn accordance with the hot air blowing the blade wear transfer dryer is divided into surfaceblowing type and side blowing type two. Above is a diagram of a face blowing type, the cylinderis horizontally arranged, the distance along the cylinder wall circumferential direction with manyleaves (blinds) from the end surface of the side inlet outlet side of tilt, hot air from the end into arotary cylinder bottom, only from the lower part of the layer material part of the blade gapblowing tube in, so it can effectively ensure the drying in the full contact of the hot air and rawmaterials, does not appear short circuit phenomenon. The material is moved by the side of the inletside of the outlet side, and the retention time of the material is moved by the side of the inlet side.Side blowing type and end blown into a pattern of different cylinder body slightly inclinedinstallation is, most of the hot air from the open has many small holes in the barrel body, blowingtube, at right angles to the direction of movement of the material in the direction and the tube andthen through triangular blades of shutter holes into material layer. A box shaped shell is arrangedaround the inner wall of the rotary drum body, and is divided into 3 and 4 independent chambersalong the length direction of the rotating cylinder. Each chamber has an independent blower, an airheater, an air inlet and an exhaust port. The hot air temperature and the circulating air volume andthe air volume can be adjusted automatically. This type of dryer volumetric heat transfercoefficient is big, about 349 - 1745w/ (m); the drying time is short, about to 10, 30min; materialsfilling rate is larger, about 20% - 30%; device volume is relatively small, material layer resistancefor 98 - 588pa; channel wind speed is generally 0.5 - 1.5m/s; cylinder speed for the conventionaldirect heating transfer dryer 1 / 2 or so; use of the hot blast temperature 100 - 300 DEG C. Inindustry often use the dryer for drying granular, lump or flaky materials, materials such as coke,compressed dry beans, sugar and avoid damage. In addition, like plastic particles are a class mustbe dried to very low moisture of material and like materials with small density ten pieces, lowpulp slag can to use it to dry.(3) ventilation tube rotary dryerThe dryer design and installation and conventional type is the same, different is cylinder isinternally provided with a mounting board copy, material from the inlet end to the outlet end of themobile process, always in a rotating cylinder at the bottom of the space, a stable material layer isformed, thus reducing the dust. The hot air enters from the end of the center pipe which is notrotated with the cylinder body, and is high speed, and is ejected from the small hole of the powderpipe which is buried in the material layer, and is in strong contact with the material. Thevolumetric heat transfer coefficient of the vent tube dryer is about two times of that of theconventional type. The circumferential speed of the rotary drum is about the conventional 1/2.Under the same production capacity, the length of the drying tube is only the conventional 1/2, sothe cost of the equipment is greatly reduced.24.2 indirect heating rotary drum dryer1 conventional indirect heating rotary drum dryerThe dryer cylinder is built in the furnace, and the shell is heated by the flue gas.A concentric cylinder is arranged inside the cylinder. The flue gas enters the annularspace between the outer shell and the furnace wall, and passes through the connectingpipe into the central tube of the drying cylinder. The conventional direct heatingrotary dryer is especially suitable for drying the materials with longer drying stage.Because it can be quite stable in the drying temperature, so that the material hasenough residence time, at the same time can be the use of rotary drum rotation,effectively prevent the agglomeration of materials. This dryer is suitable for dryingheat sensitive materials, but not suitable for high viscosity, easy to agglomeratespecial material.2 steam tube indirect heating rotary drum dryercircle heating pipe is arranged in a concentric circle in a drying cylinder, oneend of which is arranged on the drainage separation chamber of the collecting pipebox at the outlet of the dryer; the other end is provided with a heat expansion structure.The material in the dryer is heated by the opening and stirring of the heating tube andis dried, and with the help of the dryers inclination to move from the higher to thelower end, the discharge from the end of the row hopper. The dryer with conventionalindirect heating transfer all the advantages of the dryer, it per unit volume of dryingcapacity is about 3 times of that of the conventional direct heating type, thermalefficiency as high as 80% - 90%, the material filling rate of 0.1 - 0.2.2.4.3 double heating rotary dryerThe dryer is mainly composed of a rotary drum and a central inner tube. The hotair enters the inner cylinder, and the material outlet end is folded into the outercylinder, and the material is discharged from the raw material supply end. Materialmoves in the annular space along the outer wall of the housing and the inner wall ofthe central wall. The required heat, part by the hot air passing through the inner wallof the cylinder heat transfer surface, heat conduction to material; another part throughthe hot wind and materials in the shell wall and the central tube annular space in acountercurrent contact, by convection heat transfer to materials. The structure has theadvantages that the air is first passed through the inner tube, and the entrained dustcan be reduced, and the heat loss to the surrounding environment can be reduced, andthe effective utilization rate of the heat energy is improved.