制粒工藝過程的水分控制

2021/6/271影響顆粒穩(wěn)定度的因素調(diào)制20％環(huán)模15％粉碎粒度20％配方/原料40％冷卻5%2021/6/272蒸汽調(diào)制的基本作用熱－水分交換使飼料原料軟化，淀粉糊化，促進(jìn)粉料顆粒在壓粒過程中緊密結(jié)合，提高顆粒飼料的穩(wěn)定度，減少含粉量。降低制粒電耗，提高產(chǎn)量，延長環(huán)模壽命，減少因摩擦生熱導(dǎo)致的有效營養(yǎng)成分損失。2021/6/273淀粉糊化程度取決于：溫度、水分與時間制粒前的常規(guī)蒸汽調(diào)制，淀粉糊化度的提高一般不超過五個百分?jǐn)?shù)單位壓粒過程摩擦生熱導(dǎo)致的淀粉糊化無助于提高顆粒穩(wěn)定度蒸汽調(diào)制的基本作用2021/6/274調(diào)制料溫、制粒升溫與淀粉糊化的關(guān)系

2021/6/275蒸汽調(diào)制的基本作用高水分、長時間蒸汽調(diào)制，如濕法擠壓膨化的預(yù)調(diào)制過程，可使淀粉糊化度提高約20個百分?jǐn)?shù)單位。2021/6/276蒸汽調(diào)制的關(guān)鍵蒸汽質(zhì)量：什么是蒸汽質(zhì)量？如何得到高質(zhì)量蒸汽根據(jù)飼料類型和調(diào)制時間長短正確設(shè)定調(diào)制氣壓原料與成品水分控制2021/6/277蒸汽調(diào)制過程的熱交換蒸汽熱量的組成：表觀熱與潛熱潛熱---物料升溫的主要熱量來源:每凝結(jié)一個百分?jǐn)?shù)單位的優(yōu)質(zhì)蒸汽，物料溫度大約上升150C蒸汽表蒸汽質(zhì)量2021/6/278蒸汽表over2021/6/279蒸汽質(zhì)量濕蒸汽－蒸汽中含液態(tài)水,熱量低，易堵塞模孔蒸汽質(zhì)量可用氣態(tài)水在蒸汽中的百分?jǐn)?shù)來表示測定蒸汽質(zhì)量的方法過熱蒸汽或不飽和蒸汽判定過熱蒸汽的方法理想的蒸汽：100％飽和蒸汽2021/6/2710蒸汽質(zhì)量的計(jì)算

蒸汽質(zhì)量% ={[(W2xT2-W1xT1)/(W2-W1)-Hf]/Hfg}x100% W1=注入蒸汽前水重

W2=注入蒸汽前水重

T1=注入蒸汽前水溫

T2=注入蒸汽前水溫

Hf=測試壓力下的表觀熱(查蒸汽表) Hfg=測試壓力下的潛熱(查蒸汽表)2021/6/2711蒸汽表over2021/6/2712蒸汽系統(tǒng)主要設(shè)備的選擇與設(shè)定鍋爐輸汽管道內(nèi)徑的確定汽水分離器疏水閥減壓(穩(wěn)壓)器流量控制閥2021/6/2713

鍋爐的選擇與設(shè)置

BoilerSelectionandLayout

燃料的選擇要全面考慮供氣穩(wěn)定性、人工、燃料價格及環(huán)境等因素

FuelType鍋爐的功率或供氣量要留有余地

BoilerSize:

Leavesufficientroom

盡可能縮短鍋爐與用汽設(shè)施之間的距離

Locationoftheboiler:closetothepelletmill2021/6/2714ID(cm)=Wx3.53v/30W=蒸汽流量(Steamflow),kg/minv=給定氣壓下的比體積(Specificvolumeundergivensteampressure),m3/kg(查表)30=最大流速(allowedsteamflowvelocity),m/s輸汽管道內(nèi)徑的確定

SizingthePipe2021/6/2715氣水分離器

SteamSeparator根據(jù)機(jī)械原理將蒸汽中的水滴與蒸氣分開以得到優(yōu)質(zhì)蒸汽. Usingamechanicaladvicetoremovewaterdrip-letsfromthesteamandobtainhighqualitysteam.好的氣水分離器可移走98%的水滴. Goodseparatorcanremovemorethan98%ofthewaterdrip-lets2021/6/2716其功能為將凝積水(在進(jìn)入調(diào)制器前)從蒸汽系統(tǒng)中排出.

Toremovewatercondensateoutofthesteamsystem(beforethesteamgoingintotheconditioner).疏水閥應(yīng)不時啟閉使一定壓力下的凝積水移到常壓的回收系統(tǒng)且不丟失蒸気.

Itmustperiodicallyopenandclosetoallowthepressurizedcondensatetoberemovedintoanatmosphericcondensatereturnsystemwithoutlosingsteam.疏水閥

CheckValve2021/6/2717只有氣壓穩(wěn)定才能使氣流穩(wěn)定,從而保證制粒過程穩(wěn)定.

Steadypressureiscriticalforsmoothsteamflowandhencesmoothpelletingoperation.減壓有助于提高蒸汽質(zhì)量.

Pressurereductionhelpsimprovingsteamquality.減壓(穩(wěn)壓)器的主要參數(shù):流量、調(diào)壓范圍及控制的穩(wěn)定性(可用變異系數(shù)度量). Parametersforconsideration:Maximumflow(kg/hour),pressurerange,pressurestability(expressedasCV%).減壓(穩(wěn)壓)器

SteamPressureReducer-Regulator2021/6/2718控制進(jìn)入調(diào)制器的蒸汽流量.只有物料流量與蒸汽流量同步控制才能實(shí)現(xiàn)穩(wěn)定的制粒作業(yè).

Itmetersthesteamflowgoingintotheconditioningchamber-animportantdeviceforoperator調(diào)制器操作與流量應(yīng)是線性關(guān)系. Alinearresponseisrequiredbetweencontrolvalveandsteamflow.一般的控制閥的操作與實(shí)際流量不是線性關(guān)系. Thegatevalveisnon-linear-athalfopening,smallchangesinsettingresultslargesteamflowvariation.流量控制閥

SteamFlowControlValve

2021/6/2719減壓、分水、氣壓控制三合一

Aseparator-trap-pressureregulator“threeinone”device.流量控制閥在自動和手動控制條件下均與流量呈線性關(guān)系. Linearsteamflowcontrolvalvesforbothmanualandautomaticcontrolsystem- CospectValve2021/6/2720蒸汽調(diào)制系統(tǒng)參數(shù)的設(shè)定ParameterSettingsinSteamConditioning考慮因素：調(diào)制時間、蒸汽質(zhì)量、飼料配方.Factorstobeconsidered:Retentiontime,steamqualityandformulation/ingredients.對于一般飼料配方，應(yīng)在不塞機(jī)的前提下，盡可能提高料溫.

Ingeneral,mashtemperatureshouldbeconditioned“ashighaspossible”beforereachingthe“chockpoint”.2021/6/2721減壓前后的壓力比

PressureRatiobefore–afterPressureReducingValve減壓可使蒸汽中的水滴揮發(fā).減壓幅度過大,在蒸汽質(zhì)量好時,可形成過熱(不飽和)蒸汽.

Pressurereductionhelpswaterdripletsflashoffbutmayalsoproduceasupper-heatedsteamifthepressuredropistoomuchandthesteamqualityalreadyveryhigh.一般推薦:3.5-4:1 GeneralRecommendation:3-4to12021/6/2722進(jìn)入調(diào)制室的蒸汽壓力設(shè)定

SteamPressureSettingbeforeConditioner調(diào)制時間短，蒸汽質(zhì)量好，宜采用低蒸汽壓(1.5-0.5kg/cm2或

更

低)，以爭取熱交換時間(并降低能耗).

Lowpressure(0.5-1.5kg/cm2)ispreferredifretentiontimeisshort(20secorless).調(diào)制時間長，可采用較高蒸汽壓力。

Higherpressureworkswell(2-4kg/cm2)ifretentiontimeislong(40secormore).關(guān)鍵在于有足夠時間完成熱交換-釋放潛熱.

Thekeyistogivesufficienttimeforheattransfer-releasinglatentheat.2021/6/2723調(diào)制溫度≤700C以控制水分避免塞機(jī)

Keepmashtemperature≤700Ctoavoidmoistureincreasecausedstickiness可考慮采用較高蒸汽壓力甚至過熱蒸汽

Highersteampressure-lowsteamflow,orsupperheatedsteammayhelp高乳清粉乳豬料蒸汽參數(shù)的設(shè)定

SteamSettingfor

HighWheyDiet2021/6/2724延長調(diào)制時間有助于水分進(jìn)入并軟化粉料以提高顆粒質(zhì)量

Extendedretentiontimehelpsmoisturepenetrationandsoftensparticlesforbetterpellets.調(diào)制時間測定(Measuringmeanretentiontime):

MRT(Sec.)=(3600xW)/(1000xP)where,

W=調(diào)制器內(nèi)水分校正的物料量,kg

Moistureadjustedmashweightinconditioner,kg P=產(chǎn)量,MT/h

Productionrate,MT/h

蒸汽調(diào)制時間

RetentionTime2021/6/2725蒸汽調(diào)制時間

RetentionTime延長常規(guī)調(diào)制器調(diào)制時間的簡易辦法: 通過調(diào)節(jié)漿片角度提高物料在調(diào)制器內(nèi)的充滿度.ExtendingRetentionTimebyAdjustingPitchAngle夾層(間接)蒸器的作用

Theroleofindirectsteam.

2021/6/2726ExtendingRetentionTimebyAdjustingPitchAngleMashfillbeforeadjustmentthermometer2021/6/2727ConditionerPaddlePitchAdjustment(TopView)2021/6/2728MashFillafterAdjustment2021/6/2729延長調(diào)制時間的設(shè)備

多層調(diào)制器可變仰角調(diào)制器熟化調(diào)制器

RipennerDDC2021/6/2730制粒過程的自動控制料流控制蒸汽流控制料溫反饋控制，電流反饋控制2021/6/2731常規(guī)蒸汽調(diào)制的局限性

LimitstoTraditionalSteamConditioning高水分、低溫原料限制料溫升高。

Cannotachievehighmashtemperaturewheningredientmoistureishighandtemperatureislow.解決途徑：烘干-預(yù)熱？投入機(jī)械能?加壓調(diào)制?Solution:

Drying?

Pre-heating?Mechanicalenergyinput?Pressurizing?

2021/6/2732What’sNew?-ForBetterPellets-2021/6/2733制粒工藝過程的水分控制2021/6/2734控制關(guān)鍵點(diǎn)調(diào)制前粉料水分:水分低于12%在混合物機(jī)加水(一般不超過一個百分點(diǎn))調(diào)制后水分可通過料溫上升估測成品水分:通過冷卻時間－料層高度調(diào)節(jié)2021/6/27352021/6/2736以電容為基礎(chǔ)的快速水分測定器：不需樣品粉碎不需稱量測定誤差不超過0.5百分?jǐn)?shù)單位手工操作系統(tǒng)，六秒中得結(jié)果,電腦自動監(jiān)測系統(tǒng)，每秒20個以上讀數(shù)關(guān)鍵設(shè)備2021/6/27372021/6/2738制粒問題解難案例

Pelleting

TroubleShooting-CasebyCaseAnalyses2021/6/2739例1(廣東,1985)

Case1(Guangdong)問題:產(chǎn)量偏低,愛環(huán)鏌壽命低

Problem:lowproductionrate.,diewearingtofast現(xiàn)場觀察:進(jìn)入調(diào)制器蒸汽壓:2.7kg/cm2,

On-siteobservation:Steampressureatconditioner2.7kg/cm2

問題所在?如何解決?

Solution?2021/6/2740例2(美國,1990)

Case2(US-1990)問題:兔顆粒質(zhì)量差,含粉多. Problem:poorpelletqualityinarabbitdiet.現(xiàn)場觀察:未發(fā)現(xiàn)明顯異常.與工人座談得知唯一改變是粉碎玉米由廠外帶加工.

Nosignificantproblemfoundinpelletingoperation.Onlychangesrecentlymadewascornmealsuppliedfromtoll-millingbyanoutsidecontractor.

問題所在?如何解決?

Solution?2021/6/2741例3(美國,1994)

Case3(US-1994)問題:料溫上不去,顆粒質(zhì)量差,含粉多,產(chǎn)量低

Problem:Lowmashtemperature,poorpelletquality,lowproductionrate.現(xiàn)場觀察:給汽打滑,減壓前-后蒸汽壓:6.5-2.7,

手可握住疏水閥后水管. Onsiteobservation:surgingwhenaddingsteam;steampressureatboiler:6.5kg/cm,afterconditioner:2.7kg;handscanholdonpipeaftercheckvalve.問題所在?如何解決?

Solution?2021/6/2742例4(江西,1999)

Case2(JiangXi-1999)問題:成品水分.10.5%. Problem:Lowm