滾筒干燥機(jī) 開題報(bào)告 呂春輝

編號(hào)無錫太湖學(xué)院畢業(yè)設(shè)計(jì)（論文）相關(guān)資料題目： 滾筒干燥器設(shè)計(jì) 信機(jī) 系 機(jī)械工程及自動(dòng)化專業(yè)學(xué) 號(hào)： 0923011學(xué)生姓名： 呂春輝 指導(dǎo)教師： 戴寧 （職稱：副教授 ） （職稱： ）2013年5月25日目 錄一、畢業(yè)設(shè)計(jì)（論文）開題報(bào)告二、畢業(yè)設(shè)計(jì)（論文）外文資料翻譯及原文三、學(xué)生“畢業(yè)論文（論文）計(jì)劃、進(jìn)度、檢查及落實(shí)表”四、實(shí)習(xí)鑒定表無錫太湖學(xué)院畢業(yè)設(shè)計(jì)（論文）開題報(bào)告題目： 滾筒干燥器設(shè)計(jì) 信機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè)學(xué) 號(hào)： 0923011 學(xué)生姓名： 呂春輝 指導(dǎo)教師： 戴寧 （職稱：副教授 ） （職稱： ）2012年11月25日 課題來源工程實(shí)踐類的自擬課題科學(xué)依據(jù)（包括課題的科學(xué)意義；國內(nèi)外研究概況、水平和發(fā)展趨勢(shì)；應(yīng)用前景等）（1）課題科學(xué)意義干燥技術(shù)的應(yīng)用，在我國具有十分悠久的歷史，聞名于世的造紙技術(shù)就有干燥技術(shù)的應(yīng)用。干燥設(shè)備廣泛應(yīng)用于化工、食品、糧油、飼料等工業(yè)。中國的現(xiàn)代干燥技術(shù)是從20 世紀(jì)50年代逐漸發(fā)展起來的，迄今對(duì)于常用的干燥設(shè)備如氣流干燥、噴霧干燥、流化床干燥、旋轉(zhuǎn)閃蒸干燥、紅外干燥、微波干燥、冷凍干燥等設(shè)備，我國均能生產(chǎn)供應(yīng)市場(chǎng)。對(duì)于一些較新型的干燥技術(shù)如沖擊干燥、對(duì)撞流干燥、過熱干燥、脈動(dòng)燃燒干燥、熱泵干燥等也都已開發(fā)研究，有的已工業(yè)化應(yīng)用。我國的現(xiàn)代干燥技術(shù)取得的成績是我國相關(guān)科研人員和企業(yè)界共同努力的結(jié)果，雖然取得了不少可喜的成果，但是企業(yè)間的競(jìng)爭(zhēng)尚不規(guī)范阻礙了干燥技術(shù)的健康發(fā)展，很多成果尚未能轉(zhuǎn)化為生產(chǎn)力使企業(yè)的產(chǎn)品得不到更新。（2）國內(nèi)外研究概況及發(fā)展前景干燥也是一個(gè)能耗較大的單元操作，直接決定著產(chǎn)品的質(zhì)量，特別是高性能材料的生產(chǎn)，對(duì)干燥操作有著更高的要求。針對(duì)這些問題，近些年來，干燥技術(shù)領(lǐng)域出現(xiàn)了一些創(chuàng)新成果。為了節(jié)能以及生產(chǎn)附加值高的產(chǎn)品、解決干燥過程中出現(xiàn)的問題需要結(jié)合現(xiàn)存的各種有效的干燥技術(shù)，或者研究開發(fā)特殊的干燥技術(shù)和新型的干燥設(shè)備同時(shí)也需要強(qiáng)化干燥過程中的智能化控制。在油脂制取的原料干燥上目前我國此類干燥設(shè)備大部分是采用對(duì)流干燥技術(shù),主要使用滾筒烘干機(jī)、流化床烘干機(jī)和塔式干燥機(jī)。 簡(jiǎn)而言之，目前干燥技術(shù)發(fā)展的總趨勢(shì)為:a.干燥設(shè)備研制上向?qū)I(yè)化、大型化、系列化和自動(dòng)化發(fā)展。b.強(qiáng)化干燥過程。c.采用新的干燥方法和組合干燥方法。d.降低干燥過程中能量的消耗。e.閉路循環(huán)干燥流程的開發(fā)和應(yīng)用。f.消除干燥過程造成的公害問題。 研究內(nèi)容 熟悉滾筒干燥器的主要原理和結(jié)構(gòu)。 熟悉干燥過程的基本計(jì)算； 熟練進(jìn)行滾筒干燥器的結(jié)構(gòu)設(shè)計(jì)； 掌握的使用方法； 能夠熟練使用進(jìn)行三維的畫圖設(shè)計(jì)。 擬采取的研究方法、技術(shù)路線、實(shí)驗(yàn)方案及可行性分析（1）實(shí)驗(yàn)方案對(duì)滾筒干燥機(jī)進(jìn)行設(shè)計(jì)，結(jié)構(gòu)合理、布局正確，能夠正常運(yùn)行。（2）研究方法 用進(jìn)行二維畫圖，對(duì)滾筒干燥器的結(jié)構(gòu)有全面的了解。 對(duì)滾筒干燥機(jī)進(jìn)行計(jì)算與結(jié)構(gòu)設(shè)計(jì)，使其滿足工作要求。研究計(jì)劃及預(yù)期成果研究計(jì)劃：2012年10月12日-2012年12月31日：按照任務(wù)書要求查閱論文相關(guān)參考資料，完成畢業(yè)設(shè)計(jì)開題報(bào)告書。2013年1月1日-2013年1月27日：學(xué)習(xí)并翻譯一篇與畢業(yè)設(shè)計(jì)相關(guān)的英文材料。2013年1月28日-2013年3月3日：畢業(yè)實(shí)習(xí)。2013年3月4日-2013年3月17日：滾筒干燥器的主要參數(shù)計(jì)算與確定。2013年3月18日-2013年4月14日：滾筒干燥器總體結(jié)構(gòu)設(shè)計(jì)。2013年4月15日-2013年4月28日：零件圖及三維畫圖設(shè)計(jì)。2013年4月29日-2013年5月21日：畢業(yè)論文撰寫和修改工作。預(yù)期成果：滾筒干燥器可以正常運(yùn)行，完成人們所需的成品。特色或創(chuàng)新之處 設(shè)備傳熱效率高、傳熱均勻。 設(shè)備結(jié)構(gòu)簡(jiǎn)單、易操作。已具備的條件和尚需解決的問題 設(shè)計(jì)方案思路已經(jīng)明確，已經(jīng)具備機(jī)械設(shè)計(jì)能力和干燥方面的知識(shí)。 進(jìn)行結(jié)構(gòu)設(shè)計(jì)的能力尚需加強(qiáng)。指導(dǎo)教師意見 指導(dǎo)教師簽名：年 月 日教研室（學(xué)科組、研究所）意見 教研室主任簽名： 年 月 日系意見 主管領(lǐng)導(dǎo)簽名： 年 月 日英文原文Drying TechnologyThere are three main types of gas-suspension dryers: Spray dryers, to convert a liquid solution or suspension to a dry, free-flowing powder Fluid-bed dryers, used to dry wet filter cake, or for pastes and sludges with dry product recirculation Flash dryers, for a relatively dry, crumbly, non-sticky feed The type of dryer chosen for any given application depends on both the feed properties and product requirements. Important feed properties are the moisture content, solids, viscosity, and density, as well as any volatile, flammable, or toxic components. Dried product specifications may include average particle size and particle size distribution, density, moisture content, and residual volatiles or solvents. Powder characteristics can be controlled and powder properties maintained constant through continuous operation.Spray DryingSpray drying is a three-step drying process involving both particle formation and drying. (1) The process begins with the atomization of a liquid feed into a spray of fine droplets. (2) Then a heated gas stream suspends the droplets, evaporating the liquid and leaving the solids in essentially their original size and shape. (3) Finally, the dried powder is separated from the gas stream and collected. Spent drying gas is either treated and exhausted to the atmosphere or recirculated to the system. These three steps are accomplished by three components: the atomizer, the disperser, and the drying chamber.The selection and operation of the atomizer is of extreme importance in achieving an optimum operation and production of top-quality powders. There are four main types of atomization: Centrifugal atomization, the most common, uses a rotating wheel or disc to break the liquid stream into droplets. The rotational speed determines the mean particle size, while the particle size distribution about the mean remains fairly constant in a system. Centrifugal atomizers are available in a large variety of sizes, from laboratory scale to very large commercial units. Hydraulic pressure-nozzle atomization forces pressurized fluid through an orifice. Multiple nozzles are used to increase capacity. The particle size depends on the pressure drop across the orifice, so that the orifice size determines the capacity of the system. This type of atomization is simpler than centrifugal, but cannot be controlled as well. It is not suitable for abrasive materials, or materials that tend to plug the orifices. Two-fluid pneumatic atomization uses nozzles, as well, but introduces a second fluid, usually compressed air, into the liquid stream to atomize it. This type of atomization has the advantage of relatively low pressures and velocities and a shorter required drying path. It is most often used in small-scale equipment, laboratory or pilot size. Sonic atomization, not yet widely used, passes a liquid over a surface vibrated at ultrasonic frequencies. It can produce very fine droplets at low flow rates. Current limitations are capacity and the range of different product that can be atomized. After atomization, a disperser brings the heated gas into contact with the droplets. The disperser must accomplish three things: mix the gas with the droplets, begin the drying process, and determine the flow paths through the drying chamber. The drying gas may be heated directly by combustion of natural gas, propane, or fuel oil, or indirectly using shell-and-tube or finned heat exchangers. Electric heaters may be used in small dryers. Industrial radial fans move the heated gas through the system.The drying chamber must be sized to allow adequate contact time for evaporation of all of the liquid to produce a dry powder product. Factors that impact the drying time include the temperature difference between the droplets and the drying gas, and their flow rates. The exact shape of the chamber depends on the drying characteristics and product specifications, but most are cylindrical with a cone-shaped lower section to facilitate collection of the product.Finally, proper configuration of the atomizer, disperser, and drying chamber is essential for complete drying and to avoid the deposit of wet material on the interior surfaces of the dryer. Designs may use co-current, counter-current, or mixed flow patterns.The powder is separated from the drying gas at the bottom of the chamber. Most often, the gas exits through an outlet duct in the center of the cone. Heavier or coarser particles will be separated at this point, dropping into the cone to be collected through an air lock. Then either cyclones or fabric filters (or both) remove the remaining powder from the exit gas. In systems producing a very fine powder, most of the collection takes place at this point.Fluid-Bed DryingFluid-bed drying is a process in which a gas is forced upward through a bed of moist particles to achieve a fluidized state. The particles are suspended in the gas stream and dry as they flow along with the gas. Fluid beds can be either cylindrical or rectangular. There are two basic types of fluid-bed designs: Plug flow fluid beds are used for feeds that are directly fluidizable. Baffles in the bed limit mixing in the horizontal direction to maintain plug flow. This type of bed is ideal for removal of bound volatiles or for heating and cooling. The volatile content and temperature vary uniformly as the solids pass through the bed. Baffle design depends on the shape and size of the bed, with spiral or radial baffles used in circular beds and straight baffles in rectangular. Back-mixed fluid beds are used for feeds that cannot be fluidized in their original state, but become fluidizable after a short time in the dryer. The feed is distributed over the bed surface, designed to allow total solids mixing. Product temperature and moisture are uniform across the fluidized layer. Heating surfaces may be immersed in the fluidized layer to improve thermal efficiency and performance. A combination system uses a back-mixed fluid bed to reduce the moisture level of the wet feed, followed by a plug-flow section to achieve final specifications. This type of arrangement is quite common.The advantages of fluidized-bed drying are: relatively long residence times allow high heat-transfer coefficients between the particles and the gas; the ability to closely control product temperature makes fluidized beds ideal for processing temperature-sensitive solids; and they have the highest thermal efficiency of any gas-suspension drying system.Disadvantages are: they can process only a limited range of materials; product particles are relatively large; and there may be difficulty processing needle- or platelet-shaped particles.Flash DryingFlash drying forces drying gas through a heater and upward through a duct or flash tube. The high-velocity gas stream instantly suspends the feed, which enters just after the heater, and carries it to the collection equipment, usually cyclones or bag collectors.Flash dryers are the simplest gas-suspension dryers, and require the least space. Residence time within the dryer is very short, usually less than 3 seconds. Particles must be quite small, and the best feed is reasonably dry, crumbly, and not sticky. There are several ways to obtain the required feed qualities: A cage mill may be used to break up the feed into the required small particles. If the feed is too wet or pasty, dry solids may be backmixed to create the proper consistency. An agitated design, using a high-speed disintegrating rotor, will keep all particles moving. This design is shorter and larger in diameter than a flash tube, creating a very compact system. Hybrid DryersThere are a number of hydrid systems used in applications where a single system cannot handle the requirements of both the feed and product. The most common are: Fluidized spray dryers (FSD) combine spray with fluid bed drying to produce agglomerated products. The top of the system is a spray dryer, atomizing the liquid and contacting it with heated gas. Additional heated gas is introduced at the bottom to create a fluidized bed portion of the drying chamber. This type of dryer will produce a dustless, free-flowing agglomerated product. It is ideal for products that must dissolve easily, e.g. food colors, dyestuffs, pigments, and some agricultural chemicals. A flash dryer may be used to remove surface moisture, followed by a fluid bed for removal of bound moisture. Niro DryersThe MOBILE MINOR is a laboratory-scale spray dryer known for its flexibility and different levels of control systems. It is used to dry small quantities of solutions, suspensions, and emulsions into representative powder samples. Test results provide important information for selecting the design and technical specification of a given drying project.The PRODUCTION MINOR is a larger spray dryer that can be used for pilot testing or small-scale production. It has a choice of atomizers, heating systems, and powder discharge.The Fluidized Spray Dryer (FSD) was invented and patented by Niro in the early 1980s. It combines fluidization and spray-drying technologies to dry a wide variety of products, including many that cannot be dried using conventional equipment. Advantages include easy control of the size and structure of the particles, making it ideal for agglomerated products, and low powder temperatures for thermally sensitive materials. It is also very energy efficient.中文譯文干燥技術(shù)主要有三種氣體懸浮烘干: 噴霧干燥器,把液體溶液或懸浮于干燥,自由流動(dòng)的粉末 流化床干燥機(jī),用干,濕濾餅,或漿和污泥干產(chǎn)品再循環(huán) 閃蒸干燥機(jī),在相當(dāng)干燥,松軟,非飼料粘粘 該型干燥器選擇任何特定應(yīng)用取決于雙方的飼料性能和產(chǎn)品的要求. 重要飼料性能是水分含量,固形物,粘度,密度,以及任何揮發(fā)性,易燃或有毒成分. 木片產(chǎn)品規(guī)格可能包括平均粒度分布,密度,含水率,殘留揮發(fā)或溶劑. 粉末特性可控制粉末特性保持不變,通過連續(xù)運(yùn)行. 噴霧干燥. 噴霧干燥是一個(gè)三步走的干燥過程中,涉及兩種粒子形成和干燥. ( 1 )進(jìn)程始于霧化的液體飼料成噴霧霧滴. ( 2 ) ,然后加熱氣流暫時(shí)飛沫 96.3%的液體和離開固體基本上是原來的大小和形狀. ( 3 )最后,干粉分離氣流和收集. 用干燥氣體要么是治療和精疲力竭的氣氛或循環(huán)使用該系統(tǒng). 這三個(gè)步驟是由三部分組成:霧化,分散,而干燥室.選擇和操作的噴霧器,是極端重要性,實(shí)現(xiàn)最佳的操作和生產(chǎn)頂級(jí)質(zhì)量 粉末. 主要有4種霧化: 離心霧化,最常見的,用一個(gè)旋轉(zhuǎn)輪或盤打破液體流成液滴. 轉(zhuǎn)速確定的平均粒徑, 而粒度分布大約平均維持在相當(dāng)穩(wěn)定的系統(tǒng). 離心式霧化器可有多種尺寸,從實(shí)驗(yàn)室規(guī)模比較大的商業(yè)單位. 液壓噴嘴霧化勢(shì)力加壓流體通過一個(gè)小孔. 多噴頭用來增加容量. 顆粒大小取決于壓降過孔板, 使孔大小決定了系統(tǒng)的容量. 這種霧化簡(jiǎn)單得多離心,但無法控制等. 它是不適合研磨材料,或材料,往往堵塞孔口. 雙流體氣動(dòng)霧化噴嘴的用途,以及如何引進(jìn),但第二液,通常壓縮空氣 成液體流霧化. 這種霧化的優(yōu)點(diǎn)在于較低的壓力和速度,縮短干燥所需的路徑. 這是最常用的小型設(shè)備,實(shí)驗(yàn)室或中試規(guī)模. 聲波霧化,尚未廣泛使用,在經(jīng)過了超過液體表面振搗,在超聲波的頻率. 它可以產(chǎn)生非常細(xì)微的動(dòng)作,在低流率. 電流限制能力,以及各種不同的產(chǎn)品,可霧化.霧化后,使分散的熾熱氣體接觸到液滴. 分散必須完成三件事:混合氣體與霧滴,從干燥過程中, 并確定流路徑通過干燥室. 干燥氣體,可直接加熱燃燒天然氣,丙烷或燃油 或間接使用殼管式或翅片式換熱器. 電加熱器,可用于小型烘干機(jī). 工業(yè)徑向球迷提出了激烈的天然氣通過該系統(tǒng). 烘干室必須大小以便有充裕的時(shí)間接觸蒸發(fā)所有的液體產(chǎn)生 一個(gè)干粉產(chǎn)品. 因素的影響,干燥時(shí)間,包括溫差的霧滴和干燥氣體. 而其流率. 確切庭取決于干燥特性及產(chǎn)品規(guī)格, 但大多數(shù)是圓柱與錐形下段,以方便收集的產(chǎn)品. 最后,妥善配置的噴霧器,播種機(jī), 和干燥室必須徹底干燥,以避免存款濕材料的內(nèi)表面 在吹干. 設(shè)計(jì)可利用順流,逆流或混合流模式. 粉末分離的干燥氣室底部. 在多數(shù)情況下,出口氣體通過一個(gè)插座導(dǎo)管中心的錐. 較重或粗