畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
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設(shè)計(jì)（論文）題目：
環(huán)模制粒機(jī)設(shè)計(jì)
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學(xué)生姓名：
專????業(yè)：
所在學(xué)院：
指導(dǎo)教師：
職????稱：
發(fā)任務(wù)書日期：年月日
任務(wù)書填寫要求
1．畢業(yè)設(shè)計(jì)（論文）任務(wù)書由指導(dǎo)教師根據(jù)各課題的具體情況填寫，經(jīng)學(xué)生所在專業(yè)的負(fù)責(zé)人審查、系（院）領(lǐng)導(dǎo)簽字后生效。此任務(wù)書應(yīng)在畢業(yè)設(shè)計(jì)（論文）開始前一周內(nèi)填好并發(fā)給學(xué)生。
2．任務(wù)書內(nèi)容必須用黑墨水筆工整書寫，不得涂改或潦草書寫；或者按教務(wù)處統(tǒng)一設(shè)計(jì)的電子文檔標(biāo)準(zhǔn)格式（可從教務(wù)處網(wǎng)頁(yè)上下載）打印，要求正文小4號(hào)宋體，1.5倍行距，禁止打印在其它紙上剪貼。
3．任務(wù)書內(nèi)填寫的內(nèi)容，必須和學(xué)生畢業(yè)設(shè)計(jì)（論文）完成的情況相一致，若有變更，應(yīng)當(dāng)經(jīng)過所在專業(yè)及系（院）主管領(lǐng)導(dǎo)審批后方可重新填寫。
4．任務(wù)書內(nèi)有關(guān)“學(xué)院”、“專業(yè)”等名稱的填寫，應(yīng)寫中文全稱，不能寫數(shù)字代碼。學(xué)生的“學(xué)號(hào)”要寫全號(hào)，不能只寫最后2位或1位數(shù)字。
5．任務(wù)書內(nèi)“主要參考文獻(xiàn)”的填寫，應(yīng)按照《金陵科技學(xué)院本科畢業(yè)設(shè)計(jì)（論文）撰寫規(guī)范》的要求書寫。
?6．有關(guān)年月日等日期的填寫，應(yīng)當(dāng)按照國(guó)標(biāo)GB/T 7408—94《數(shù)據(jù)元和交換格式、信息交換、日期和時(shí)間表示法》規(guī)定的要求，一律用阿拉伯?dāng)?shù)字書寫。如“2002年4月2日”或“2002-04-02”。
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
1．本畢業(yè)設(shè)計(jì)（論文）課題應(yīng)達(dá)到的目的：
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1.通過畢業(yè)設(shè)計(jì)，使學(xué)生對(duì)所學(xué)課程能融會(huì)貫通，能靈活運(yùn)用各類知識(shí)；并使得到深化、鞏固和提高。
2.全面系統(tǒng)地進(jìn)行一次有關(guān)機(jī)械工程設(shè)計(jì)的基本訓(xùn)練，培養(yǎng)學(xué)生的工程能力。
3.培養(yǎng)學(xué)生獨(dú)立分析、解決問題的能力。通過畢業(yè)設(shè)計(jì)檢驗(yàn)學(xué)生對(duì)所學(xué)課程的掌握程度及對(duì)所學(xué)知識(shí)的應(yīng)用能力，以此作為評(píng)定學(xué)生畢業(yè)設(shè)計(jì)成績(jī)的主要依據(jù)之一。
2．本畢業(yè)設(shè)計(jì)（論文）課題任務(wù)的內(nèi)容和要求（包括原始數(shù)據(jù)、技術(shù)要求、工作要求等）：
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1.中，英文摘要（300字）；
2.外文翻譯（近期文獻(xiàn)或?qū)Ｖ?000字）（需單獨(dú)裝訂
3.建模軟件熟練應(yīng)用
4.環(huán)模制粒機(jī)主體結(jié)構(gòu)設(shè)計(jì)、建模
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
3．對(duì)本畢業(yè)設(shè)計(jì)（論文）課題成果的要求〔包括圖表、實(shí)物等硬件要求〕：
?? 1、畢業(yè)設(shè)計(jì)說明書
2、相關(guān)裝配圖及其主要零件圖一套
3 控制流程圖
4、外文參考資料譯文（附原文）
5 鼓勵(lì)做拓展性研究
4．主要參考文獻(xiàn)：
［1］李潤(rùn)萍．淺談小型一步制粒機(jī)在中藥制粒中關(guān)鍵因素的控制[J]．江 西中醫(yī)學(xué)院學(xué)報(bào)，2006
［2］曹康，金征宇．現(xiàn)代飼料加工技術(shù)[M].上海：上?？茖W(xué)技術(shù)文獻(xiàn)出版社，2003
［3］張培建，吳建國(guó)．飼料制粒機(jī)自動(dòng)控制研究[J]．機(jī)床與液壓，2008
［4］李秀華，唐旭生．PLC對(duì)藥丸包衣制粒機(jī)控制系統(tǒng)的改造[J]．可編程控制器與工廠自動(dòng)化，2005
［5］王斌斌．環(huán)模制粒機(jī)自動(dòng)控制系統(tǒng)[J]．現(xiàn)代農(nóng)業(yè)裝備，2007
［6］陳義厚，周思柱．三錐輥式平模制粒機(jī)的設(shè)計(jì)與研究[J]．機(jī)械設(shè)計(jì)與制造，2007，
［7］劉守祥．粉狀飼料混合制粒機(jī)的設(shè)計(jì)[J]．機(jī)械研究與應(yīng)用，2007
［8］何明霞，馬英，王康等．新型小型高速混合制粒機(jī)的設(shè)計(jì)[J]．醫(yī)藥工程設(shè)計(jì)，2007，
［9］黃傳海．蝦飼料制粒機(jī)的設(shè)計(jì)[J]．廣東飼料，2002
［10］陳雨田，孫湘．P2m×6m膠輪磨擦傳動(dòng)圓筒混合制粒機(jī)設(shè)計(jì)與分析[J]．湖南有色金屬，2003
［11］何占松，李愛華，姜燕飛，等．小型平模飼料制粒(塊)機(jī)結(jié)構(gòu)參數(shù)的關(guān)系[J]．農(nóng)村牧區(qū)機(jī)械化，2007
畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書
5．本畢業(yè)設(shè)計(jì)（論文）課題工作進(jìn)度計(jì)劃：
2015.12.13—2016.03.09? 畢業(yè)設(shè)計(jì)調(diào)研；開題報(bào)告；英文翻譯；
2016.03.10—2016.04.06?? 畢業(yè)設(shè)計(jì)查閱；收集資料；論文提綱；
2016.04.07—2016.05.04?? 畢業(yè)設(shè)計(jì)實(shí)驗(yàn)方案程序設(shè)計(jì)與優(yōu)化；
2016.05.05—2016.05.11?? 畢業(yè)設(shè)計(jì)全套材料；
2016.05.12—2016.05.17??畢業(yè)設(shè)計(jì)論文預(yù)審；畢業(yè)設(shè)計(jì)答辯；
所在專業(yè)審查意見：
?通過?
負(fù)責(zé)人： ??????????? ?2016? 年??? 1 ?月???18 ?日
畢 業(yè) 設(shè) 計(jì)（論 文）開 題 報(bào) 告
設(shè)計(jì)（論文）題目：
環(huán)模制粒機(jī)設(shè)計(jì)
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學(xué)生姓名：
專????業(yè)：
所在學(xué)院：
指導(dǎo)教師：
職????稱：
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?年? ?月??日 ?
開題報(bào)告填寫要求
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1．開題報(bào)告（含“文獻(xiàn)綜述”）作為畢業(yè)設(shè)計(jì)（論文）答辯委員會(huì)對(duì)學(xué)生答辯資格審查的依據(jù)材料之一。此報(bào)告應(yīng)在指導(dǎo)教師指導(dǎo)下，由學(xué)生在畢業(yè)設(shè)計(jì)（論文）工作前期內(nèi)完成，經(jīng)指導(dǎo)教師簽署意見及所在專業(yè)審查后生效；
2．開題報(bào)告內(nèi)容必須用黑墨水筆工整書寫或按教務(wù)處統(tǒng)一設(shè)計(jì)的電子文檔標(biāo)準(zhǔn)格式打印，禁止打印在其它紙上后剪貼，完成后應(yīng)及時(shí)交給指導(dǎo)教師簽署意見；
3．“文獻(xiàn)綜述”應(yīng)按論文的框架成文，并直接書寫（或打印）在本開題報(bào)告第一欄目?jī)?nèi)，學(xué)生寫文獻(xiàn)綜述的參考文獻(xiàn)應(yīng)不少于15篇（不包括辭典、手冊(cè)）；
4．有關(guān)年月日等日期的填寫，應(yīng)當(dāng)按照國(guó)標(biāo)GB/T 7408—94《數(shù)據(jù)元和交換格式、信息交換、日期和時(shí)間表示法》規(guī)定的要求，一律用阿拉伯?dāng)?shù)字書寫。如“2004年4月26日”或“2004-04-26”。
5、開題報(bào)告（文獻(xiàn)綜述）字體請(qǐng)按宋體、小四號(hào)書寫，行間距1.5倍。
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畢 業(yè) 設(shè) 計(jì)（論文） 開 題 報(bào) 告
1．結(jié)合畢業(yè)設(shè)計(jì)（論文）課題情況，根據(jù)所查閱的文獻(xiàn)資料，每人撰寫不少于1000字左右的文獻(xiàn)綜述：
1.概述
隨著經(jīng)濟(jì)的發(fā)展，飼料工業(yè)已經(jīng)成為國(guó)名經(jīng)濟(jì)的重要基礎(chǔ)產(chǎn)業(yè)之一。在畜禽業(yè)中，飼料是支撐畜禽生長(zhǎng)的最基本元素，顆粒飼料具有體積小、不易受潮、便于散裝儲(chǔ)存和運(yùn)輸?shù)鹊戎T多有點(diǎn)，而且用顆粒料喂養(yǎng)畜禽還有營(yíng)養(yǎng)較均衡，飼料浪費(fèi)少、喂養(yǎng)方便、節(jié)約勞動(dòng)力的特點(diǎn)。由于顆粒飼料與普通飼料比較的種種優(yōu)勢(shì)，顆粒飼料在配合中的比例逐年上升，因此，為了確保顆粒飼料的產(chǎn)量、質(zhì)量，研發(fā)能生產(chǎn)高品質(zhì)的顆粒飼料的機(jī)器設(shè)備也是勢(shì)在必行。
飼料制粒機(jī)械包括設(shè)備較多，主要有制粒機(jī)、冷卻機(jī)、粉碎機(jī)、分離機(jī)和噴漆設(shè)備等，其中顆粒飼料制粒機(jī)是加工顆粒飼料的核心設(shè)備。顆粒飼料制粒機(jī)在很大程度上決定了飼料加工產(chǎn)量，因此在飼料生產(chǎn)中就占有重要了地位。目前，我國(guó)已經(jīng)開發(fā)出具有自己知識(shí)產(chǎn)權(quán)的環(huán)模制粒裝配系統(tǒng)和以環(huán)模制粒機(jī)為核心的顆粒飼料生產(chǎn)成套生產(chǎn)線自控生產(chǎn)系統(tǒng)，并在一定基礎(chǔ)上得到了使用，這可以滿足目前我國(guó)國(guó)內(nèi)對(duì)建設(shè)大型的顆粒加工廠對(duì)裝配的需求，但此項(xiàng)技術(shù)的智能化程度較低，且生產(chǎn)線的大型水平與國(guó)外的先進(jìn)水平還有一定的差距。
可見，研究高效節(jié)能的制粒技術(shù)對(duì)農(nóng)業(yè)的發(fā)展具有非常重要的意義，因此，設(shè)計(jì)處低耗、高產(chǎn)能的環(huán)模制粒機(jī)對(duì)提高我國(guó)制粒機(jī)方面的國(guó)際競(jìng)爭(zhēng)力、促進(jìn)三農(nóng)的發(fā)展和提高飼料機(jī)械的整體設(shè)計(jì)及制造水平具有重要的理論意義和實(shí)用價(jià)值。
2.研究現(xiàn)狀
（1）國(guó)內(nèi)外環(huán)模制粒技術(shù)的技術(shù)現(xiàn)狀
國(guó)外技術(shù)現(xiàn)狀
擁有了完善的技術(shù)體系：發(fā)達(dá)國(guó)家在環(huán)模制粒裝備技術(shù)體系上已經(jīng)健全，能夠提供優(yōu)質(zhì)、高效的設(shè)備和完善的問題解決方案。國(guó)際上著名的環(huán)模制粒設(shè)備企業(yè)有瑞士的BUHLER公司、美國(guó)的CPM公司、奧地利的ANDRITZ公司、德國(guó)的MUNCH公司、丹麥的Sprout-Matador公司等，它們?cè)诃h(huán)模制粒的成型技術(shù)方面研究比較早，已經(jīng)形成了晚上的技術(shù)體系。
可靠性高，高效、節(jié)能、環(huán)保：國(guó)外環(huán)模制粒裝備的企業(yè)重視基礎(chǔ)研究，其制造的關(guān)鍵部位的零件使用壽命超過國(guó)內(nèi)同類產(chǎn)品的2-3倍；裝備的材質(zhì)和潤(rùn)滑油的使用都充分考慮環(huán)保的問題；應(yīng)用除 除臭的在線檢測(cè)技術(shù)；對(duì)結(jié)構(gòu)和工藝參數(shù)進(jìn)行了優(yōu)化，技能效果顯著。
向大型化、智能化方向邁進(jìn)：國(guó)外制粒裝備時(shí)產(chǎn)50t甚至達(dá)到100t的環(huán)模裝備已經(jīng)成為主流，這些機(jī)器設(shè)備的自動(dòng)化程度較高，能夠?qū)嵕€無人操作，并且能夠?qū)崿F(xiàn)一鍵開機(jī)和全過程智能監(jiān)控。
成套化、智能化程度高，實(shí)現(xiàn)顆粒飼料生產(chǎn)的只能管理：國(guó)外企業(yè)在裝備集成化的基礎(chǔ)上開發(fā)出了管-控一體化，實(shí)現(xiàn)了從半自動(dòng)生產(chǎn)單元到大規(guī)模的全自動(dòng)生產(chǎn)過程的控制系統(tǒng)的自動(dòng)化服務(wù)，使其具有工藝流程的優(yōu)化與控制、能量消耗的優(yōu)化、設(shè)備狀況的實(shí)時(shí)監(jiān)測(cè)和管理等多種功能，實(shí)現(xiàn)了顆粒飼料生產(chǎn)的精細(xì)化管理。
國(guó)內(nèi)技術(shù)現(xiàn)狀：
擁有相對(duì)完善的環(huán)模制粒裝備產(chǎn)業(yè)體系和技術(shù)體系，但其技術(shù)平臺(tái)和基礎(chǔ)研究相對(duì)滯后：我國(guó)制粒裝備已形成相對(duì)完善的體系，基本能夠滿足國(guó)內(nèi)的各種生產(chǎn)應(yīng)用需求。但總體來說，我國(guó)的制粒裝備技術(shù)平臺(tái)和基礎(chǔ)研究相對(duì)來說比較滯后，產(chǎn)品的設(shè)計(jì)缺乏先進(jìn)試驗(yàn)和檢測(cè)技術(shù)條件的支撐；環(huán)模制粒裝備技術(shù)方面的人才還比較短缺，這極大制約了產(chǎn)品的創(chuàng)新力度和技術(shù)水平。
部分指標(biāo)已經(jīng)接近國(guó)際的先進(jìn)水平，但總體技術(shù)水平和國(guó)際的先進(jìn)水平還有較大的差距：今年我國(guó)成功開發(fā)雙齒輪驅(qū)動(dòng)制粒機(jī)、雙軸分功能制粒機(jī)、雙級(jí)同步帶驅(qū)動(dòng)制粒機(jī)、平模制粒機(jī)、雙輥制粒機(jī)等多種新型的制粒裝備，制粒機(jī)的適應(yīng)性能不斷提高；對(duì)環(huán)模、壓輥的幾何參數(shù)和環(huán)模轉(zhuǎn)速等的結(jié)構(gòu)、工藝參數(shù)在不斷優(yōu)化，在提高質(zhì)量的前提下不斷降低能耗；設(shè)計(jì)了新型環(huán)模、壓輥的調(diào)節(jié)機(jī)構(gòu)，提高了裝配和維修的效率；對(duì)環(huán)模和壓輥間的磨損問題進(jìn)行了各種分析研究，使環(huán)模和壓輥的使用壽命不斷提高。雖然我國(guó)在環(huán)模治理裝備方面有了長(zhǎng)足的發(fā)展，但在綠色環(huán)保、核心部件使用壽命等核心指標(biāo)與國(guó)際先進(jìn)水平還有相當(dāng)大差距，急需提升和改進(jìn)。
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2．本課題要研究或解決的問題和擬采用的研究手段（途徑）：
1.本課題所要研究的問題：
通過對(duì)國(guó)內(nèi)外環(huán)模制粒機(jī)現(xiàn)狀的分析，我們對(duì)環(huán)模制粒機(jī)已經(jīng)有了比較清晰的認(rèn)識(shí)，它是重要的飼料機(jī)械產(chǎn)品，因此，研究其結(jié)構(gòu)設(shè)計(jì)具有十分重要的意義。目前，國(guó)內(nèi)外對(duì)其研究方向不同，國(guó)外對(duì)環(huán)模制粒機(jī)的研究方向主要集中在機(jī)理分析與試驗(yàn)研究，而國(guó)內(nèi)對(duì)于其的研究主要在產(chǎn)品的介紹、設(shè)計(jì)方式和工藝因素對(duì)其制粒的影響。因而，國(guó)外的制粒機(jī)種類比較齊全，性能比較優(yōu)異，而國(guó)內(nèi)的品種比較單一，性能相對(duì)落后，試驗(yàn)數(shù)據(jù)不夠充分，即缺乏相應(yīng)的技術(shù)支撐。本文通過對(duì)環(huán)模制粒機(jī)的機(jī)理分析，對(duì)環(huán)模制粒機(jī)的主體結(jié)構(gòu)進(jìn)行設(shè)計(jì)計(jì)算。
具體研究?jī)?nèi)容包括：
（1）對(duì)環(huán)模制粒機(jī)進(jìn)行結(jié)構(gòu)和主要參數(shù)分析；
（2）對(duì)環(huán)模制粒機(jī)主體部分零部件進(jìn)行設(shè)計(jì)、選型；
（3）利用CAD畫出環(huán)模制粒機(jī)主體部分裝配圖和相關(guān)的零件圖。
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譯文題目：Wet granulation in a batch high shear mixer
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abstract
This study deals with the wet granulation in a high shear mixer. The experimental apparatus is a laboratory scale ”L?dige” granulator,with a maximum volume of 20 l, equipped with a chopper and a pneumatic spraying system. The main objective of the study is to point out the effect of physico-chemical properties and operating conditions on the growth mechanisms and kinetics in this type of granulation device. Two kinds of alumina with different particle size distributions (alumina SH100 and alumina SH30) were granulated using various Newtonian liquids having different surface tension, viscosity, binder concentration, density, etc. (water, aqueous solutions of polyethyleneglycol or polyvinyl alcohol). Experimental results showed that the granulation process generally proceeds through three distinct growth regimes independent of the nature of the powder, the binder liquid or the operating conditions. However, the transition between different regimes depends on the physico-chemical properties of the solids and liquids, on operating conditions and on the experimental procedure. For the alumina powder used in this study the transition occurs when a degree of liquid saturation of about 68% is reached.
Keywords: wet granulation machine; growth mechanism; high shear mixer; L?dige; alumina
1. Introduction
Granulation is a size enlargement process widely used in several branches of the chemical industry. The aim of this operation could be to improve flowability, appearance or proportioning of powders or to avoid dust production,etc.
Among all existing size enlargement operations, wet granulation in high shear mixers is particularly interesting as it allows one to obtain regular shaped granules with a high degree of compaction. The process uses a liquid species, called the binder, to hold particles together while they are mixed by mechanical agitation.
Since the pioneering works of Newitt and Conway-Jones (1958) and Capes and Danckwerts (1965) wet granulation has been a subject of fundamental and applied research.
Number of books and review papers are available, which summarise the state of the knowledge in this field (e.g. Iveson et al., 2001; Kapur, 1978, Capes, 1980; Pietsch, 1991;Ennis et al., 1991; Hoornaert et al., 1998; Rumpf, 1962; Leuenberger et al., 1979, Kristensen et al., 1985a,b). The various mechanisms involved in wet granulation are known to be wetting and nucleation; consolidation and growth; and breakage and attrition. However, the theoretical aspects of the granulation are not sufficiently understood to quantitatively predict the effect of physico-chemical properties and operating conditions on the growth rate and dominant mechanism.
Leuenberger et al. (1979) was the first to find an agreement between the tensile strength as a function of the degree of saturation and the power consumption profile ofthe mixer motor when adding progressively a liquid to the powder mass.
Nevertheless, Ennis et al. (1991) recently found that capillary forces play the principal role only in low viscosity systems. For more viscous binder liquids the viscosity should be recognised as an important parameter in controlling granulation behaviour. These authors developed a microlevel-based model to take into account the effect of viscous dissipation on the strength of a dynamic pendular bridge formed by a Newtonian liquid.
2. Experimental
2.1. Experimental set-up
Experimental apparatus used in this study were 1 represents. This means having a total volume of 20L batch L?dige mixing equipment and is equipped with a water flow downward pneumatic spray system. All parts are made of stainless steel. The mixing chamber is a bedroom cylindrical bowl. Four radial mixing impeller driven by a motor shaft support level distribution at 90 degree angle mounted on the ploughshare shovel. Stirring speed of the impeller can be transferred from 0-230. On the bowl is also equipped with an installed base of tulip shaped rotary chopper. In operation, the chopper speed at 2800 rpm, the opening at the top of the bowl allows loading and emptying the mixer. After the required amount of powder and loading hatch cover to prevent dust distribution. In addition, the cover support atomizer system is an internal two-fluid nozzle flat jet produced as 80 degrees.
Creep pump from the reservoir for storing (kept at 25 degrees) to the nozzle feed granulation liquid.
figure 1
2,2 material
Experiments using two commercial alumina granulator for type SH100 and sh30 were two products they include non-porous and irregular shaped particles. Before granulating machine experiment, particle size distribution and density prior to using Malvern Mastersizer analyzer and helium pycnometer Determination, some details are provided in Table 1 against the two products physical properties.
Table 1
Several Newtonian liquid adhesive is to be used. Their properties are summarized in Table 2. Use pycnometer liquid density measurement. Using a capillary rheometer to measure liquid viscosity. The surface tension of the liquid and solid - liquid contact angle is measured using a krypton üSS K1 tension Wilhelmy plate method and Washburn meter capillary rise method used.
Table 2
2,3 Experimental Procedure
Before granulator experiments, the powder is introduced into the mixer granulator and to the same conditions of use in a mixed state. A complete granulation process consists of two steps:
he amount of granulation liquid required during ? "crush" or wetting step at a constant flow rate control and sprayed into the mixer.
"Mature" maintained by the pulverization step after mixing components. It should be noted that only a limited number of mature step study experimental operation.
After each operation, the entire granulated product is removed from the mixer and tested to determine the following standard granulators: the intensity distribution within the particle porosity and saturation (DLS).
2,3,1 particle size distribution
The wet granules are screened for analysis, allowing determination of the particle size distribution of the mass, which in turn is estimated to be allowed.
? mass median diameter D50mm, an average diameter of the particles, which is found in 50% of the flour mass smaller diameter particles. The diameter is calculated from the cumulative particle size distribution come.
? fine, intermediate and rough parts are arbitrarily defined. While most of the size of the particles are smaller than 0.315mm, 0.315mm and between 3.15mm, greater than 3.15mm, the middle part of it is the corresponding products for the market
In addition, the particle diameter distribution of the particles measured by the number of subdivisions established Malvern Mastersizer analyzer using a dry method.
2,3,2 The average particle density and performance of intermediate porosity
We point out that the performance of the particle density is a non-binder particles include the proportion of the volume and quality voids within the particles. To measure this parameter, first, a wet granulation is screened through a sample was distilled into the narrow sections, each separately be analyzed according to the order of about: wet granules significant samples (at least 250) to calculate and dried in 60 ° oven 24 coax hour. Assuming a uniform density and particle filter diameter spherical particles, the apparent density of the particles is calculated by the following equation:
(1)
wherein n is the number of particles in the analysis sample, c is the dry granulation liquid may contain in mass fraction (solute), dˉ study population average particle size of the particle, mw and md are wet and oven-dried sample weight .
Then with particle porosity within the computing
(2) where s is the true density of the dried powder, which is measured with a helium pycnometer experimentally determined.
2,3,3 liquid saturation
DLS particle is defined as the granulation liquid occupies a whole section of the particles within the space, this parameter is calculated by the following formula:
(3)Where is the density of the liquid granulator.
It is worth noting that saturation must be distinguished from liquid / solid ratio, L / S, which is the introduction of the total mass of the liquid and powder ratio definition.
3. Results and discussion
A series of operating conditions are summarized in Table 3. In this study experiments. Note that, a series of experiments including an increase of granulation liquid (ceteris paribus) the number of runs, resulting in a longer time scale of the development of the data generation of particles.
table 3
3,1 granulated Profile
Figure 2 shows the particle size distribution of the liquid / solids ratio of the function of the evolution of a typical, L / S, the data presented in Figure 2 can be seen from, L / S ratios as high as the distribution size distribution 20.7% w / w of the particles did not change significantly, more than the value of the particles gradually accelerating growth, reducing the number of segments, the size distribution of the ratio L / S of nearly 24% by wide until the "lumps" or too wet phenomenon.
Figure 2
To understand the mechanism of production of particles, there are three types of evolution: thin (less than 0.315mm), coarse (greater than 3.15mm) and the intermediate particles in Figure 3 shows the average diameter. When the ratio L / S increases three consecutive Trend Watch: wherein when the ratio of fine and coarse particles substantially constant first public method, followed by the second method, the second method in which the proportion of fine particles and other reduction of two match. However, the median diameter and L / S no major development. As well as a sharp increase in the proportion of the ratio of the value of the average particle diameter and L / S Finally, the third method is observed large particles.
It is noteworthy that, unfortunately, can not be studied at low L / S ratio of granulated behavior because of low mechanical strength of the particles in the screening process, resulting in a high turnover rate. However, taking into account the maximum size of less than SH100 alumina particles 40 microns, which can be evidenced by the zero method granulator previously existing "core" steps are appropriate.
Introduction described herein three pellet mill is all experimental observation of unrelated powder, liquid adhesive, or operating conditions. However, the conversion between different methods depending on the liquid adhesive and the environment created by the mixer (i.e. impeller speed, chopper operation or not operation, etc.). Also important is the transition zone L / S ratio Note that the second and third methods of narrow spacing between places. The reason is that the second method occurs later we can see a small saturation range (75-90%).
3,2 granulation mechanism
image 3
In fact, the conversion between different mechanisms is obvious, and their growth trend is clearly different, suggesting a variety of mechanisms have different primary mechanism components. To point out that these mechanisms are useful inspection, in addition to the distribution, the interior of the porous particles change in particle size, DLS (FIG. 4) as well as the thickness dimension granulated in a granulator distribution (FIG. 5).
3,2,1 a mechanism
Figure 4 illustrates a first mechanism, the intra-particle porosity decrease almost linearly with increasing liquid saturation. On the other hand, FIG. 6 shows an SEM image of the obtained intermediate particles corresponding to the L / S ratio of the first three different mechanisms, 14.3%, 17.1% and 20.0%. As can be seen, in the first mechanism, the shape and orientation of the particles is not largely different. Thus, it can be concluded in the first mechanism is the main mechanism under shear agitation impeller of a particle densification. This conclusion is supported by the fact that, whether partial or intermediate average diameter of the particles in the first mechanism remains unchanged (Fig. 3).
However, densification is not the only mechanism leading growth, because it can not explain the fine surface also gathered in the L / S ratio is greater than 17.1% of the median particle surface. Thus, in the first mechanism in L / S ratio increases at a high value of densification, agglomeration occurs between the intermediate and fine particles. However, a surprising phenomenon in the first part of the mechanism of fine particles does not change a lot, which means to produce fine particles mainly of fine particles from the broken left intermediate equilibrium particles. As it can be seen from Figure 5, the L / S ratio of at least bimodal particle size distribution. The larger the number of focus 100 microns, but more sophisticated model number from the L / S ratio of 30 microns to 50 microns 14.3% of the L / S ratio of 17.1%. When L / S ratio increases, however small feature reduces the increase in the proportion of the second part features. In view of the SEM image shows fine characteristics of the second level is not caused by the finer particles; we can conclude that, from the characteristics of the second intermediate particle breakage portion. As a first characteristic, since the median particle group promotions, it disappears, this conclusion is confirmed by scanning electron microscopy (FIG. 6), which indicates that the adhesion of fine particles in the intermediate size is close to the first level. Please note that this phenomenon does not affect the average porosity of the particles in the liquid and saturation (Figure 4). The results showed that the wettability and having a particle densification occurs in all classes and in a similar manner. This balance between the two phenomena (by preferentially binds to disappear by forming a first characteristic and a second characteristic of the particle fracture) reported with the experimental described here by chance, can not be generalized. In fact, as we can see in the back, as at higher impeller speed, the relative amount of the second characteristic of fine particles of the first characteristic is growth.
Figure 4
Finally, and most importantly, when the particles to achieve high dynamic light scattering (≈68%), the conversion will take place the first and second methods. At such a high saturation, while some of the free liquid surface is available, the particles may grow further back. Another interesting phenomenon is the liquid saturation and L / S ratio is not linear increases. This is because, in addition to wetting, the densification phenomenon helps to increase saturation.
Figure 5
3.2.2 Mechanism of two
Observation showed that the particle size distribution, particle reduction second mechanism portion and the intermediate portion of the corresponding
Figure 6 A(17.1%) B(20.0%) C(20.7%)
Figure 7
increase. Furthermore, the intermediate SEM image (FIG. 7) clearly shows the presence of the size in the 50-200 micron agglomerates of fine particle surface. However, the shape of the agglomerates remained spherical. These results indicate that the primary mechanism to the second mechanism between the particle growth of the fine particles and the second characteristic intermediate characteristic are present in proportions of randomly agglomerated clumps. The transition between the second and third mechanism occurs when the fine particle fraction is almost completely consumed.
Mechanism of 3,2,3 three
In the L / S ratio SEM image of the resulting sample is higher than 22.1% (Figure 8) showed that these intermediate particles are composed of several fragments and "raspberry" structure, in the region of irregular particle shape, surface less smooth. This evolution is evident particle size distribution, increasing coarse content of fine particles damage, and damage to a higher degree of intermediate particles. In addition, the particle size distribution of the intermediate portion sizes from small to high dimensional translation. Increasing the average median diameter of the intermediate portion resulting from this change, the mechanism is reduced to the intermediate portion of the mechanism in the third, the results can be seen from Figure 3 due to the growth achieved by the merger. From the observation can be concluded, the growth mechanism of the third mechanism is the dominant priority to the proportion of fine particles is loaded into a combination of intermediate or coarse particles.
Figure 8
4 .Conclusion
The main objective of this work is, first, to understand the mechanism of the granulator, followed by a number of high-shear mixer L?DIGE noted physicochemical properties and operating conditions on the growth mechanism and kinetics of the main objectives of this work is to first to understand the mechanism of the granulator, followed by a number of high-shear mixer L?DIGE noted physicochemical properties and operating conditions on the mechanism and kinetics of growth. Powder binders have been several studies (powder: liquid two-alumina of different particle size distributions: water, aqueous polyethylene glycol, and polyvinyl alcohol aqueous solution, alcohol) affected. Powder binders have been several studies (powder: liquid two-alumina of different particle size distributions: water, aqueous polyethylene glycol, and polyvinyl alcohol aqueous solution, alcohol).
Experimental data show that due to the increased amount of liquid, the granulation process regardless of the nature of the powder, liquid binder or operating conditions through the use of three different growth mechanisms. The presence of these three mechanisms granulator profile show up each by a different mechanism of growth mechanisms.
In different time intervals, samples were removed from the granulator analysis showed that the growth mechanism includes a sample of each method was determined to be the following. In the first stage, the mechanism of the granulator nuclear primary particles (zone 0), which follows the first mechanism, does not create new species cohesion. In this method, which consists of a balance of wear and tear, to create a good particles or agglomerates and growth mechanism of fine particles (agglomeration, stratification); on the other hand, in the second mechanism, the random stratified fine aggregate particulate matter adsorbed on the growth of other species. This mechanism between the first and the second transition management densification and binder particles to the surface of the particle transport phenomena. The results showed that the powder for use in this study, the first transition occurs in a liquid saturation of 68% of independent operating conditions. Finally, when the fine aggregate is completely exhausted, there area a third of small and large particles in a granulating mechanism is perfect coalescence mechanism.
Finally, amplification tests showed that industrial-scale granulator (130L) was confirmed in a laboratory-scale granulator observed granulator outline three methods.
參考文獻(xiàn)
1. Capes, C.E., 1980. Handbook of Powder Technology: vol. 1, Particle Size Enlargement. Elsevier, Amsterdam.
2. Capes, C.E., Danckwerts, P.V., 1965. Granule formation by the agglomeration o