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n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 1 N MN HC QU TRNH V THIT B THIT K H THNG SY CHUIBNG HM SY Sinh vin thc hin: TRN TH THU HIN B Mn: Cng Ngh Sinh Hc Gio vin hng dn: KS. Nguyn Th Xun Mai Thng 5 nm 2012 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 2 B GIO DC V O TOCNG HA X HI CH NGHA VIT NAM TRNG I HC LC HNG c lp - T do - Hnh phc NHIM V N H v tn sinh vin: Nguyn Th Dung MSSV: 108002516 Nguyn Th HinMSSV: 108002343 Trn Thu Thu Hin MSSV: 108003357 Kha: 2008Khoa: CNSH-MTNgnh: Cng Ngh Sinh Hc 1.u n: Thit k h thng sy chui 2.Cc s liu v d liu ban u: - m ban u 80%, m sn phm kh 12% -Nng sut nhp liu: 4tn /20h -Khng kh bn ngoi: 27oC v m 79% -Ch sy: nhit tc nhn vo 80 oC, thi gian sy trong 8 gi -Ngun cung cp nng lng: Hi nc bo ha 3.Ni dung thuyt minh v tnh ton: -Tng quan -Quy trnh cng ngh -Tnh ton s b -Thit k ch to hm sy -Tnh thit b ph 4.Cc bn v, th ( ghi r cc loi v kch thc bn v): -Bn v quy trnh cng ngh. -Cc bn v chi tit. 5.H tn ging vin hng dn: Nguyn Th Xun Mai 6.Ngy giao nhim v n: 15/3/2012 7.Ngy hon thnh n: 18/5/2012 Bin Ha, ngy 18 thng 5 nm 2012 Ch nhim b mnGing vin hng dn Sinh vin hon thnh n v np n QT-TBngy.thngnm 2012 Cn b phn bin n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 3 NHN XT CA GING VIN ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ............................................................................................................................ ..................................................................................................................................... n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 4 LI M U Trong nhng nm gn y nn nng nghip nc ta t c nhiu thnh tu to ln.Ngoivicpng nhu cu tiudng nia, nc ta bt u xut khu nng sn cng vi cc ch phm ca n. Do vic ng dng cc cng ngh mingmtvaitrhtscquantrng.Trong,cngnghsylkhuquan trong trng trong cng ngh sau thu hoch, ch bin v bo qun nng sn. Sylmtqutrnhcngnghcsdngtrongrtnhiungnhcng nng nghip. Qu trnh sy khng chi l qu trnh tch nc v hi nc ra khi vt liu mt cch n thun m l mt qu trnh cng ngh. N i hi sau khi sy vt liu phi m bo cht lng cao, tiu tn nng lng t v chi ph vn hnh thp. thchinqutrnhsyngitasdngmththnggmnhiuthitbnh thitbsy(hmsy,thpsy,thngsy,v.v),thitbtnngtcnhn (clorifer) hoc thit blm lnh lm khtc nhn, qut, bmvmt s thit b phnhhmt,xyclon,v.vChngtagihthngccthitbthchinmt qu trnh sy c th no l mt h thng sy. Hm sylmt trongnhng h thng sy i lu thng dng nht. Nu h thng sy hm l h thng sy tng m, nng sut khng ln v c th t chc cho tc nhn sy i lu t nhin hoc cng bc th h thng sy hm c nng sut ln hn, c th sy lin tc hoc bn lin tc v lun lun l h thng sy i lu cng bc. Sy nng sn l mt quy trnh cng ngh phc tp. N c th thc hin trn nhngthitbsykhcnhau.ngvimtloinngsntacnchnchsy thchhpnhmtnngsutcao,chtlngsnphmsyttvtitkimnng lng. Trong n ny, em c giao nhim v thit k mt h thng sy dng cho vic sy sn phm l qu chui chn. Vi nhim v , em la chn cng ngh sy hmvitcnhnsylkhngkhcgianhitvnhqutthivo.Hthng nuclpttithnhphBinHavinhitkhngkhvmtrung bnh trong nm l t = 27,3oC; = 79%[10]. y l ln thit k n sy u tin nn trong qu trnh thit k cn nhiu bt cplthuyt,vkinthccnhnch,knhmongquthycthngcmvtn n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 5 tnh gip . Nhn tin y em xin chn thnh cm n C Nguyn Th Xun Mai tn tnh hng dn chng em hon thnh n ny.Bin Ha, ngy 18thng 5 nm 2012 Ngi thit k n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 6 MC LC DANH SCH CC HNH ......................................................................................... 9 DANH SCH CC BNG ........................................................................................ 9 CHNG 1. TNG QUAN V NGUYN LIU QU CHUI ........................... 10 1.1. Cc loi chui chnh Vit Nam .......................................................... 10 1.2. c im c bn ca chui ................................................................... 10 1.3. Gi tr dinh dng ca qu chui .......................................................... 11 1.4. Cng dng ca chui ............................................................................. 11 1.5. Tnh cht vt l c bn ca chui .......................................................... 12 CHNG 2. TNG QUAN V PHNG PHP SY CHUI .......................... 13 2.1. Bn cht ca qu trnh sy ..................................................................... 13 2.2. Phn loi qu trnh sy .......................................................................... 13 2.3.Nhn t nh hng n qu trnh sy chui ......................................... 14 2.4. Cng ngh sy chui ............................................................................. 15 2.4.1 chnh ca chui nguyn liu .............................................................. 15 2.4.2. H tr vic ra bt chui bng ho cht ................................................ 16 2.4.3. Hiu qu dit khun ca tia cc tm ....................................................... 16 2.4.4. Xc nh m cn bng ca chui sy ................................................ 16 2.4.5. Cc ch tiu cht lng ca chui sy xut khu ................................... 17 2.5 Cng ngh sy chui qu........................................................................ 17 CHNG3.PHNTCH,LACHNPHNGPHP,DNGVCH SY ........................................................................................................................... 20 3.1. Cc yu cu t ra ca vic thit k ...................................................... 20 3.1.1. Lng m cn bay hi tnh theo gi ...................................................... 20 3.1.2. La chn phng php sy .................................................................... 20 3.2. Chn ch sy ........................................................................................ 20 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 7 3.3. S cng ngh ca h thng sy ............................................................ 21 CHNG 4: TNH TON CN BNG NHIT M CA H THNG SY .... 22 4.1 Cc thng s ca khng kh trong h thng sy ..................................... 22 4.1.1 Thng s ca khng kh ngoi tri .......................................................... 22 4.1.2 Thng s ca khng kh sau thit b sy................................................ 22 4.1.3 Thng s ca khng kh sau bung ha trn ........................................... 24 4.1.4 Thng s ca khng kh sau Calorifer .................................................... 25 4.2 Lu lng khng kh kh l thuyt ........................................................ 25 4.2.1 Lng khng kh kh l thuyt lu chuyn trong thit b sy ................ 25 4.2.2 Lu lng khng kh kh ngoi tri l thuyt cp vo thit b sy ........ 26 4.3. Cc thng s trng thi ca tc nhn sy .............................................. 26 4.4 Xc nh kch thc ca thit b sy..................................................... 26 4.4.1 Kch thc ca khay sy ......................................................................... 27 4.4.2 Kch thc ca xe gong ......................................................................... 27 4.4.3 Kch thc ca hm sy ...................................................................... 28 4.5 Tng cc tn tht nhit trong h thng sy ............................................ 29 4.5.1 Tn tht nhit do vt liu sy mang i .................................................... 29 3.5.2 Tn tht nhit do thit b truyn ti ......................................................... 29 4.5.3 Tn tht nhit qua kt cu bao che......................................................... 30 4.6 Tnh ton qu trnh sy thc ................................................................... 34 4.6.1 Thng s ca khng kh sau thit b sy................................................ 35 4.6.2 Thng s ca khng kh sau bung trn ................................................. 35 4.6.3 Thng s khng kh sau khi ra khi Calorifer........................................ 36 4.7 Lu lng khng kh kh thc t cn dng ........................................... 37 4.7.1 Lng khng kh kh thc t lu chuyn trong thit b sy ................... 37 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 8 4.7.2 Lng khng kh kh ngoi tri thc t cp vo cn thit ..................... 37 4.8 Nhit lng cn cung cp cho tc nhn sy t Calorifer ....................... 38 CHNG5.TNHTONCCTHITBPHTHITKCALORIFER- CHN QUT ........................................................................................................... 40 5.1. Tnh ton thit k calorifer .................................................................... 40 5.1.1 Cc thng s c bn yu cu thit k calorifer ................................... 40 5.1.2 Tnh ton thit k calorifer: ..................................................................... 40 5.2. Qut ....................................................................................................... 47 5.2.1. Tnh tr lc: ............................................................................................ 47 5.2.2. Tnh chn qut: ....................................................................................... 52 KT LUN ............................................................................................................... 54 TI LIU THAM KHO ........................................................................................... 55 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 9 DANH SCH CC HNH Hnh 1.1. Hnh dng qu chui ......................................................................... 10 Hnh 2.1. Chui sy thnh phm ...................................................................... 19 Hnh 3.1. S cng ngh ca h thng ......................................................... 21 DANH SCH CC BNG Bng 1.1. Thnh phn ha hc c bn ca chui ............................................ 11 Bng 5.1 Cn bng nhit ca h thng sy...................................................... 39 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 10 CHNG 1. TNG QUAN V NGUYN LIU QU CHUI 1.1. Cc loi chui chnh Vit Nam Chui c nhiu loi nhng c 3 loi chnh: - Chui tiu ( cn gi l chui gi ) - Chui gong ( cn gi l chui ty, chui s, chui Xim ) - Chui bom 1.2. c im c bn ca chui Chuilmtloiqudi,vnhnvhunhcquanhnm.Chuic ngun gc t khu vc Malaysia. Loi tri cy ny bt u tr nn ph bin trn th gii t th k 20 v pht trin tt nht nhng ni c kh hu nhit i. Chng c trng chyu phc v cho m thc, cho vic sn xut si bng, dng trong ngnh cngnghipdtvchtogiy.Chngtacththngthcloiqunybng cchntrctipqukhichn,hoccthchbinthnhnhiumnnhpdn khcnhautchui,chnghnnhccloibnhchui,ccmnsaladhoaqu, bnh nng, cc mn trng ming,... Chui cng c nhiu mu sc v kch c khc nhau. Khi chn, qu chui c th c mu vng, mu sm, hoc mu ta (hay mu trng quc). C tt c hn 50 loi chui khc nhau trn th gii. c im chung v hnh dng ca chui l qu chui c gn kt vi nhau thnh bung, mi bung c chia thnh nhiu ni, v trn mi ni c khong t 10 n 20 qu . Chui l mt trong nhng qu rt tt v Hnh 1.1. Hnh dng qu chui http://amthucbonmua.vn/nhung-thong-tin-thu-vi-ve-qua-chuoi-366.html n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 11 c nhiu cng dng, c bit l chui chn cy. Khi chn, tinh bt c trong chui s c chuyn ha thnh ng t nhin, v v th chui chn thng c v ngt du v thm. 1.3. Gi tr dinh dng ca qu chui Thnh phn ha hc c bn ca qu chui Gm cc cht:Ncng kh SacarozaAxit hu c Tinh bt PrtitAxit amin LipitTaninVitamin (mg %) Tro 76,3814,182,350,3263,2980,920,0831,130,0680,5650,7 ng 2.1. Thnh phn ha hc c bn ca chui Chuichamtlnglnproteinvhyrat-cacbon.Trongchuicnbao mtsloingkhcnhaunhngglucozo,nglactoza,ngmantoza, nggalactoze,ngsucrza(ngma),ngfructoza,vtinhbt.Chui cngrtgiuccloivitaminnhVitaminA,C,E,VitaminB2,sinhtR,dng chtniacin,VitaminB12vmtskhongchtnhst,canxi,magi,photpho, kmvflorua.Ngoiracncccaxitaminthityunhchttryptophan,lizin, leuxin,glyxin,khongchtacginincngctrongthnhphncachui.Trong mt qu chui,n c th cha trung bnhmt lng calo l 100 n 125 calo. C th ni, chui l mt loi qu rt tt cho sc khe v l mt loi thc phm rt giu nng lng. 1.4. Cng dng ca chui Chuicdngnhmtphngthucchabnhrthiuqu.Hnna, do chng c cha lng ng kh cao nn cng c xem nh mt loi thc phm giu nng lng. Vi nhng gi tr dinh dng thit yu, loi hoa qu ny mang li mt s li ch cho sc khe. - Chui rt tt trong vic ci thin h tiu ha v khi phc chc nng hot ng ca rut. Chui cng gip ch gim thiu b to bn. Trong trng hp b tiu chy, c th chng ta s mtmt lng cht in gii quan trng, nu n chui s gip c th khi phc li cht in gii, v trong chui c cha lng kali cao. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 12 - Axit bo c trong chui xanh gip nui dng cc t bo nim mc d dy. Nhng t bo ny rt c hu ch trong vic hp th canxi mt cch hiu qu, rt cn thit cho s pht trin khe mnh ca h xng. -Chtaminoacidtryptphanctrongchuiscchuynithnhcht serotonin,gipgimthiucctriuchngtrmcmvcithintmtrng.Nh vy, chui l mt phng thuc rt tt nhm gim cng thng v tnh trng b stress. - n chui thng xuyn gip gim nguy c thoi ha im vng, mt trong nhng nguyn nhn gy gim th lc ngi cao tui. - Do cha hm lng kali cao v lng natri thp, nn chui chnh l s la chn thch hp gim thiu nguy c b huyt p cao v t qu. -Chuicngrtgiucchpchtphenolicgipchngloha,vthn chui thng xuyn cn gip ngn nga nguy c ung th thn. -Dohmlngstcaonnchuigiptngthnhphnhemoglobintrong mu v gim thiu bnh thiu mu. 1.5. Tnh cht vt l c bn ca chui -Khi lng ring: = 977 kg/m3 -Nhit dung ring:c = 1,0269 kJ/kg. -H s dn nhit : = 0,52 W/m. -Kch thc ca qu chui: ng knh: 2 5 cm -Di :8 20 cm -Khi lng : 50 200 gr - m vt liu sy: + m ca chui trc khi a vo sy:e1 = 75 80 % + m ca chui sau khi sy :e2 =15 20 % -Nhit sy cho php: t = (60 90) 0C n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 13 CHNG 2. TNG QUAN V PHNG PHP SY CHUI 2.1. Bn cht ca qu trnh sy Sylsbchinccasnphmbngnhitnhitthchhp,lqu trnh khuch tn do chnh lch m b mt v bn trong vt liu, hay ni cch khc do chnh lch p sut hi ring phn b mt vt liu v mi trng xung quanh.2.2. Phn loi qu trnh sy Ngi ta phn bit ra 2 loi: -Sy t nhin: nh tcnhn chnh l nng, gi... Phng php nythi gian sydi,tndintchsnphi,khiuchnhvmcuicngcavt liu cn kh ln, ph thuc vo iu kin thi tit kh hu. -Sy nhn to: qu trnh cn cung cp nhit, ngha l phi dng n tc nhn sy nh khi l, khng kh nng, hi qu nhitv n c ht ra khi thit bkhisyxong.Qutrnhsynhanh,diukhinvtrithnsyt nhin. Nu phn loi phng php sy nhn to, ta c: Phn loi theo phng thc truyn nhit:Phngphpsyilu:ngunnhitcungcpchoqutrnhsylnhit truyn t mi cht sy n vt liu sy bng cch truyn nhit i lu. y l phng php c dng rng ri hn c cho sy hoa qu v sy ht. Phng php sy bc x: ngun nhit cung cp cho qu trnh sy l thc hin bng bc x t mt b mt no n vt sy, c th dng bc x thng, bc x hng ngoi. Phng php sy tip xc: ngun cung cp nhit cho vt sybng cch cho tip xc trc tip vt sy vi b mt ngun nhit. Phng php sy bng in trng dng cao tng: ngun nhit cung cp cho vt sy nh dng in cao tn to nn in trng cao tn trong vt sy lm vt nng ln. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 14 Phng php sy thng hoa: c thc hin bng lm lnh vt sy ng thi ht chn khng cho vt sy t n trngthi thnghoa ca nc, nc thot ra khi vt sy nh qu trnh thng hoa.Phng php sy tng si: ngun nhit t khng kh nng nh qut thi vo bung sy mnh v lm si lp ht, sau mt thi gian nht nh, ht kh v c tho ra ngoi. Phng php sy phun: c dng sy cc sn phm dng lng. Bc x: s dn truyn nhit bc x t vt liu nng n vt liu m. Phn loi theo tnh cht x l vt liu m qua bung sy: Sym:vtliungynhocchuynngquabungsynhiuln,n khi hon tt s c tho ra. Sy lin tc: vt liu c cung cp lin tc v s chuyn ng ca vt liu m qua bung sy cng xy ra lin tc. Phn loi theo s chuyn ng tng i gia dng kh v vt liu m: Loi thi qua b mt. Loi thi xuyn vung gc vi vt liu. 2.3.Nhn t nh hng n qu trnh sy chui Trong qu trnh sy chui qu xy ra mt lot bin i ha sinh, ha l, cu trc c hc v cc bin i bt li khc, lm nh hng ti cht lng sn phm. Nhng bin i c hc bao gm s bin dng, nt, cong queo, bin i xp ...S thay i h keo do pha rn (protein, tinh bt, ng,..) b bin tnh thuc v nhng bin ihal.Nhngbinihasinhtrongqutrnhsylnhngphnngto thnhmelanoidin,caramen,nhngphnngxyhavpolymehacchpcht polifenol, phn hy vitamin v bin i cht mu. Hm lng vitamin trong chui qu sy thng thp hn trong chui qu ti v chngbphhymtphntrongqutrnhsyvxltrckhisy.Trongcc vitaminthaxitascobicvcarotenbtnthtldoqutrnhxyha.Riboflavin nhy cm vi nh sng, cn thiamin b ph hy bi nhit v s sunfit ha. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 15 trnh hoc lm chm cc bin i khng thun nghch y, cng nh to iu kin m thot ra khi chui qu mt cch d dng, cn c ch sy thch hp cho tng loi sn phm. Nhit sy: Nhit sy cng cao th tc sy cng nhanh, qu trnh cng c hiu qu cao. Nhng khng th s dng nhit sy cao cho sy chui qu v chui qu l sn phm chu nhit km. Trong mi trng m, nu nhit cao hn 60oC th protein b bin tnh; trn 90oC th fructoza bt u b caramen ha, cc phn ngtoramelanoidin,polimehacchpchtcaophntxyramnh.Cn nhitcaohnna,chuiqucthbchyVvy,sychuiquthng dng ch sy n ha, nhit sy khng qu cao. Ngoi ra, m tng i ca chui, m cn bng .. nh hng trc tip n qu trnh sy. 2.4. Cng ngh sy chui 2.4.1 chnh ca chui nguyn liu Chuikhithuhiphigingha,lcthtchn.Tuynhinchuit chn th chui chn chm v khng ng lot. Dm d l cch chui chn u v nhanh. chncachuinguynliulmtyutquytnhnchtlngchui sy.Cnhiucchxcnhchn,trongcchxcnhtheomuvlph bin nht. Trong ch bin hoc n trngming chui thng c dng theo 3 chn sau y: - V vng hai u xanh v ngt m , hi cht, hi cng, cha tht thm, v cn chc, chui c hm lng ng axit cc i, cn c tinh bt v tanin. - V vng hon ton v ngt, cht gim, thm,v d bc. ng v axit bt u gim, tinh bt v tamin cn t. - V vng c mu chm nu v ngt, thm, khng cht, mm v d gy. ng, axit hu c gim, tinh bt hu nh khng cn, tamin cn rt thp. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 16 2.4.2. H tr vic ra bt chui bng ho cht Trnbmtchuicmtlpbtbaoquanhnukhngcloibslm chuicmutrngloanglvxx.loiblpbtnyngitaxoachui bngtaytrongchuncchakhong3kgchui/3ltnc,mimcn23 pht.Vic chn ho cht h tr cng vic ny nhm 2 mc ch: -Gim thi gian thao tc. -Ci thin mu sn phm. Hochtcchnphir,khngc,khnggymivchosnphm, khngnhhngtingithaotcvdngc,lmbongnhanhlpbt,ctnh kh. Thng thng chn mt s ho cht ph bin sau:hn hp dung dch (NaHSO3 v HCl) hoc hn hp dung dch (NaHSO3 v Al2(SO4)3). T hp dung dch hiu qu nht l (HCl 0,05 % + Al2(SO4)3) 0,5 % . HCl nng trn khng nh hng xu n ngi sn xut v phng tin bo h lao ng, d mua, d x l, chi ph thp.Ctcdngthayimitrngccphnnghosinhkhngclivst trng nh. Phn chua nng trn cng c tc dng st trng nh, tng cng b mt cu trc cho chui, khng gy v cht, gi r, d s dng. 2.4.3. Hiu qu dit khun ca tia cc tm Sau khi sy kh chuic lm ngui v phc hi trng thi do htm tr li c mm do nht nh (do sy n m di 20%) ri mi ng gi. Thi gian ny thng t vi gi n vi ngy. Trong mi trng kh quyn thng thng vkhngthchinnghimchnhvsinhcngnghip,snphmdbnhimvi sinh vt. Nhiu c s s dng n tia cc tm dit khun coi l bin php an ton cn thit cho v sinh thc phm. 2.4.4. Xc nh m cn bng ca chui sy m cn bng ca chui sy l hm lng nc ca n trong mi trng xc nh (t v xc nh ca khng kh) m khng xy ra qu trnh nh nc (bc hi) hay ht nc (hp th) gia n v mi trng. Chui sau khi sy n m di m cn bng thng l 15 20% sau vi gi n vi ngy ngoi khng kh s tng hm lng m ti m cn bng. Xc n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 17 nh m cn bng ca chui sy nhm chn m c li khi kt thc sy v ra cch x l ng gi, bo qun ph hp. Mun bo qun chui sy tt cn gi m ca n di 25 % tt nht l 20 22 %. Do vy sau khi sy kh nn qut ngui v la chn ng gi ngay, khng nn ngoi khng kh lu s lm cho m ca chui sy thp hn m cn bng. Nu cha la chn bao gi ngay th tr trong bao kn ni kh mt hm sau x l. Bao b cn lm t vt liu chng khng kh m i qua v dn kn.2.4.5. Cc ch tiu cht lng ca chui sy xut khu 2.4.5.1. Ch tu cm quan - Trng thi : Mm do, n hi, khng c qunh, chc, cng, sng. - Mu sc : T nu n vng , tng i ng u trong mt ti, khng c thm en, nu xn, nu , khng c loang l. -Mi v :V ngt v mi c trng ca chui sy, khng c cht hay chua do ln men.2.4.5.2. Ch tiu l ho - Kch thc : Loi nguyn qu di khng qu 7 cm - m : 20 22 % 2.4.5.3. Ch tiu vi sinh vt - cn trng Lng vi sinh vt tnh bng s t bo/g sn phm 2.5 Cng ngh sy chui qu Talachncngnghsylcngnghsyhmvphhpvitnhcht ca vt liu sy v yu cu v nng sut khng qu ln nn la chn cng ngh sy hmlhplcvyucucngnghvihiuqukinht,vitcnhnsyl khng kh c gia nhit nh i qua Calorifer dng kh hi khng kh c nhit vokhong8095oC,cqutthicngbcvohmsy.Vntccadng khng kh nng ph thuc vo lng m thot ra trong mt n v thi gian. Yucuivichuinhinliu:Chuiquphttriny,titt, nguyn vn, sch s. V chui mng, d bc, c mu t vng ton tri n vng c chm nu. Rut chui mm nhng cha nh, hng thm, v ngt, khng cht. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 18 QUY TRNH CNG NGH: Chui nguyn liu ( thu hoch) Phn loi bc v ra ha cht(ln 1) ct lt ra ln2 sy phn loi x l n tia t ngoi (nu c) ng gi bo qun Thuyt minh quy trnh: Chui nguyn liu em ra sch, bc v, ct u ri ra li v lau nh lm sch cc lp trong v qu cn dnh li v lp ngoi rut qu. Sauemxlhachtnhngmvodungdchcanxiclorua(24%),natri cacbonat (5%) nhng hiu qu nht l sunfit ha bng phng php kh hoc bng phng php t. Khi sunfit ha, ngi ta nhng rut chui vo dung dch c hm lng SO2 t do l (0,2 1)% trong (520)pht. Sau khi x l bng ha cht chui c cho vomyctlyri xp vo cc khaytre hoc nhm va vo thit b sy hm hoc bung.Sy nhit 80 95oC cho n khi m ca chui gim xung cn 10 12%. Sau khi sy xong, cn tin hnh phn loi loi b nhng c thkhngtchtlng(dochyhocchatmyucu).Dngvtliu n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 19 thngdngbovrauqukhlgiycctngvchtdo(PE,PVC, xenlophan).Baogiyvhpcctngcctnhnh,r,cthtisinh,nhng thm hi thm kh, khng u di tc dng ca nc v c hc. Bao ti cht do c c tnh trong sut, n hi, d dng kn bng nhit, chi ph thp nhng c mt s b thm nc, thm kh (PE), chu nht km (PVC,PET).Bao ti cht do dng bo qun hoa qu kh c th ch gm mt mng cht do hoc kt hp nhiu mng.
Hnh 2.1. Chui sy thnh phm (http://www.hoaphatfood.vn/13-chuoi-say.html) n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 20 CHNG 3. PHN TCH, LA CHN PHNG PHP, DNG V CH SY 3.1. Cc yu cu t ra ca vic thit k 3.1.1. Lng m cn bay hi tnh theo gi Vi nguyn liu l qu chui a vo h thng sy c m W1 = 80% v yu cu ca sn phm sy u ra c m l W2 = 12%. Vithilnglmviccamtngyl20ting(baogmttcccvic nh (tho v cht ti). Do trong 1h th lng nguyn liu a vo l:
tn/20hDo vy nng sut sn phm (VLK) tnh theo gi l:
Lng m cn bay hi trong gi l:
3.1.2. La chn phng php sy Do sn phm sy l chui qu v c dng lm thc phm cho con ngi nn phi m bo yu cu v sinh. Do ta s dng phng php sy dng khng kh lm tc nhn sy. Vi yu cu v c tnh ca loi vt liu sy l chui v nng sut sykhng qu ln chdng mc trung bnh nn ta la chn cng ngh sy hm kiu i lu cng bc dng qut thi. KhngkhngoitriclcsbriquaCaloriferkhhi.Khngkh c gia nhit ln n nhit thch hp v c m tng i thp c qut thi vohmsy.Trongkhnggianhmsykhngkhkhcthchinvictrao nhit - m vi vt liu sy l qu chui lm cho m tng i ca khng kh tng ln, ng thi lm hi nc trong vt liu sy c rt ra ngoi. Khng kh ny sau c thi ra ngoi mi trng. 3.2. Chn ch sy Vi h thng sy l hm v vt liu sy l Chui qu. Ta s gia nhit cho khng khlnnnhitt1=80oC(lachntheoyucucngngh).Nhitca n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 21 khng kh ra khi hm sy ta la chn l t2 = 50oC (la chn khng c qu thp trnh hin tng ng sng bn trong bung sy khi khng kh b qu bo ha). Doyucunhitsykhngquthp(synng)nntasdngssy khng c t nng trung gian. Tronghthngsyilu,tnthtnhitdotcnhnsymangilrtln. ng thi, sn phm sau khi sy c dng lm thc phm cho con ngi nn yu cu cht lng kh cao. Do vy, khng kh s dng lm tc nhn sy yu cu phi sch,trnhsdnglngkhngkhtingoitriqulnvagytngchiph vnhnhvlcbicahthngccphinlc,tasdngchsyhilumt phntcnhnsy.Tclchomtphntcnhnsysaukhirakhithitbsy quaytrlitrchocsauCalorifertndngnhitvtlcatcnhnsy nhitt2.Vichsynygipgimbtchiphvnnglngvtrnhlm mt hng v ca chui chn. 3.3. S cng ngh ca h thng sy Tng hp cc yu cu trn v h thng, ta a ra c s h thng p ng c cc yu cu trn sau: Hi nc bo ha Vt liu m (VL G1-W1) khng khQut cp (t1;1) thingoi tri(t0;0)(tM;M)(t1;1)ra ngoi t0=27oC; (L) 0=79% Vt liu (L0) Caloriferkh Lc bi(t2;2) Kh-hi (VLK G2-W2) (L0)Nc ngng Qut hi Hnh 3.1. S cng ngh ca h thng Bungha trn Hm sy n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 22 CHNG 4: TNH TON CN BNG NHIT M CA H THNG SY A Qu trnh sy l thuyt 4.1 Cc thng s ca khng kh trong h thng sy 4.1.1 Thng s ca khng kh ngoi tri Vi cc thng s ca khng kh ngoi tri cho l t0=270C, 0=79% ta xc nh c cc thng s cn li ca khng kh nh sau: -Phn p sut bo ca hi nc nhit t0=270C l pbh0 = 0,0361 bar (tra bng V.II, trang 100, [10]) - cha hi ca khng kh:
kg_m/kg_kkk -Entanpi ca khng kh: I0 = 1,004t0 + d0(2500 + 1,842t0) = 1,004.27 + 0,042(2500 + 1,842.27) = 74,27 kJ/kg_kkk Nh vy khng kh ngoi tri (0) c: t0=270C, 0=79%, d0= 0,0185 kg_m/kg_kkk, I0 = 74,27 kJ/kg_kkk 4.1.2 Thng s ca khng kh sau thit b sy (thng s ca khng kh thi ra ngoi cng nh khng kh hi lu ti bung ha trn) Vi nhit ca khng kh kh khi c thi vo bung sy l: t1=800C, nhit ca khng kh khi ra khi bung sy l t2=500C. Lng khng kh lu chuyn trong thit b sy l: L= LH + L0. Cn bng m cho ton b h thng sy c: L0.d0 + G1.W1 = L0.d2 + G2.W2 L0.(d2 d0) = G1.W G2.W2 = W (Lng m cn ly i ca vt liu sy).
(cng thc 5.7, trang 57, [8]) Cn bng m cho ring thit b sy c: L.dM + G1.W1 = L.d2 + G2.W2 (cng thc 5.28, trang 64, [8]) Cn bng m cho ring thit b sy c: L.dM + G1.W1 = L.d2 + G2.W2 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 23 L.(d2 dM) = G1.W G2.W2 = W => L =W.
Ta c h s hi lu:n = LHL0 L-
(cng thc 5.27, trang 64, [8]) n=Wd2-dMWd2- d0-1
=
=
Cn bng nng lng cho bung ha trn c: I0.L0 = I2.LH = (L0 + LH).IM
(cng thc 5.32, trang 65, [8]) Nh vy ti im ha trn M c:
;
Qu trnh sy l thuyt xy ra trong thit b sy l qu trnh ng Entanpi nn c: I1 = I2 Cpk.t1 + d1.(r + Cpa.t2) = Cpk.t2 + d2.(r + Cpa.t2) Dod1=dM (QutrnhgianhitngdungmxyratrongCalorifer).Thay vo c:
(
) Ta rt ra c:
(
)(
)
Thay vo vi: t1 = 80oC, t2 = 50oC, d0 = 0,0185 kg_m/kg_kkk, r = 2500 kJ/kg,Cpk = 1,004 kJ/kg., Cpa = 1,842 kJ/kg., n = 1. Ta c:- cha hi ca khng kh ra khi thit b sy l: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 24
=0,043 kg_m/kg_kkk. -Entanpi ca khng kh ra khi thit b sy l: I2 = 1,004.t2 + d2.(2500 + 1,842.t2)= 1,004.50 + 0,043.(2500 + 1,842.50) = 161,66 kJ/kg_kkk -Phn p sut bo ha ca hi nc nhit t2 = 50oC l pbh2=0,12335 bar (tra bng 3, trang 192, [1]) - m tng i ca khng kh ra khi thit b sy:
2.
kq
bh2
2
Nh vy khng kh ra khi thit b sy (2) c: t2 = 50oC, 2= 51,5%, d2 = 0,043 kg_m/kg_kkk, I2 = 161,66 kJ/kg_kkk. 4.1.3 Thng s ca khng kh sau bung ha trn Khng kh sau bung ha trn l trng thi im (M) c: - cha hi ca khng kh sau bung ha trn l: dM
-Entanpi ca khng kh sau bung ha trn l: IM
-Nhit ca khng kh sau bung ha trn l: tM
-Phn p sut bo ha ca hi nc nhit t2 = 38,7oC l pbh2=0,068 bar (tra bng 3, trang 192, [1]) - m tng i ca khng kh sau bung ha trn l:
2.
kq
bh2
M
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 25 Nh vy khng kh sau bung trn (M) c: t2 = 38,7oC,
= 68,07%; dM = 0,03075 kg_m/kg_kkk, IM = 117,965 kJ/kg_kkk. 4.1.4 Thng s ca khng kh sau Calorifer (i vo thit b sy) KhngkhsauCaloriferhaykhngkhivothitbsyltrngthiim (1) c: - cha hi ca khng kh sau Calorifer l: d1 = dM = 0,03075 kg_m/kg_kkk -Entanpi ca khng kh sau bung ha trn l: I1 = 1,004.t1 + d1.(2500 + 1,842.t1)= 1,004.80 + 0,03075.(2500 + 1,842.80) = 161,72 kJ/kg_kkk -Phn p sut bo haca hi nc nhit t1 = 80oC l pbh2=0,473 bar (tra bng 3, trang 192, [1]) - m tng i ca khng kh sau bung ha trn l:
1.
kq
bh1
1
Nh vy khng kh i vo thit b sy (1) c: t1 = 80oC,
= 9,7%; d1 = 0,03075 kg_m/kg_kkk, I1 = 161,72 kJ/kg_kkk. 4.2 Lu lng khng kh kh l thuyt 4.2.1 Lng khng kh kh l thuyt lu chuyn trong thit b sy
(cng thc 5.18, trang 61, [8]) Lu lng khng kh kh l thuyt lu chuyn trong thit b sy l:
Vi nhit trung bnh ca dng kh lu chuyn trong thit b sy l: ttb= 0,5.(80 + 50) = 65oC = tb = 1,044 kg_kkk/m3_kkk Do , lu lng th tch khng kh lu chuyn qua thit b sy l: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 26
4.2.2 Lu lng khng kh kh ngoi tri l thuyt cp vo thit b sy
Lu lng khng kh kh ngoi tri l thuyt cp vo cn thit l:
Vi nhit ca khng kh ngoi tri l
Do lu lng th tch khng kh cp vo cn thit l:
4.3. Cc thng s trng thi ca tc nhn sy
Vt liu m
Hi nc bo ha (200kg/h-80%) (tM=38,7oC;M=68,07%)(t1=80oC;1=9,7%)(t1=80oC;1=9,7%)
khng kh Qut cp ngoi tri (M) thi rat0=27oC; (L) ngoi 0=79% Vt liu
Calorifer kh Lc biKh-hi (45,45%-12%) Nc ngng Qut hi
4.4 Xc nh kch thc ca thit b sy (khay sy, xe gong, hm sy) p ng yu cu v nng sut. Thit b sy ca ta la chn l hm sy. Vt liusylchuiticchtlncckhayvcckhaycchtlnccxe Bungha trn Hm sy n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 27 gong y vo hm sy. Sau khi sy xong th m ca hm v a xe gongra ngoi.4.4.1 Kch thc ca khay sy Khaysydngxpvtliusy(chuitictltdykhong50mm). Khay sy c ch to t nhm, to hnh bngphngphp dp nhm tm bng c chiu dy 1mm, kch thc ca khay sy l 1200x800, nh hnh v, to g mp ngoikhong30mmthuntintrongviccmnm.Khilngcamikhay sy tnh ra khong 3,5kg/khay.Din tch phn khay cho php cht ti ln l: 50x1050=0,65(m)x1,05(m)=0,7
. Vi kch thc nh vy khi ta cht vt liu sy (chui ti) thnh mt lp ln trn b mt li thp th trn mi khay cho php cht ln t 20-25 lt ti, vi trng lng mi ming chui ti l t 450g tr ln th trn mi khay cho php cha t 9-11,5kg. tnh trung bnh ta la chn trn mi kh cho php cht ln l 10kg. Do vy vi yu cu nng sut sy l
trn tng thi gian lm vic l 20h trn mi ngy nn s khay cn c ch to l: 4.4.2 Kch thc ca xe gong XegongcchtotkhungInoxkhngg,ccthanhInoxrngctit din 25x25, dy 1,5mm c hn li vi nhau. Trn mi xe t 12 khay, mi khay cha c 10kg vt liu sy, cc khy c xp trn mi tng khay t cch nhau vikhongcchl100mmmboluthngcatcnhnsy(khngkh nng) c d dng, di cc chn ca xe c b tr cc bnh xe c th trt c trn 2 thanh ray lp bn trong hm sy. Xe gong c ch to c kch thc: LxWxH(LengxWidthxHigh)=850x1250x1660mm.Kchthcxegong nh vy l ph hp vi iu kin gia cng cng nh ch lm vic ca cng nhn. Vi kt cu nh vy khi lng ca mi xe vo khong 28kg. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 28 Trn mi xe gong cho php t 12 khay sy, mi khay cha c 10kg. Do khi lng VLS trn mi xe l:
Vi thi gian lm vic trn mi ngy l t = 20h, thi gian sy l . Do sy ht c
th s xe gong cn thit l:
(
) . Ta ch to d ra 2 xe, do vy tng s xe gong cn ch to l 12 xe. 4.4.3 Kch thc ca hm sy Hm sy c xy dng theo kch thc m bo thun li vic di chuyn ca ccxegong,thuntinchovicyxevocngnhkoxerakhihmsy. Hm sy c xy dng theo cc kch thc s b sau: a)Chiu rng ca hm sy
Chiu rng ca hm ph thuc vo chiu rng ca xe gong. Ta ly d ra 2 pha mp tri v mp phi ca xe l 100mm xe di chuyn dc theo hm sy c d dng:
b)Chiu cao ca hm sy
Chiu cao ca hm ph thuc vo chiu cao ca xe goong. Ta ly d ra pha mp trn ca xe l 150mm xe di chuyn dc theo hm sy c d dng:
c) Chiu di ca hm sy
: Chiu di ca hm ph thuc vo chiu div s lng caxe gong lm vic trong hm. Ta ly d ra pha ca vo v ca ra mi pha l 1000mm gip cho vic y xe goong cng nh ko ra khi hm c thun li:
Trong h thng sy ca ta btrmt knh dn gi nng(nhit
),mt knh dn gi thi v mt knh dn gi hi. Cc knh c xy dng vi chiu rng hp l gip cho vic lp t thit b, vn hnh v bo dng c thun tin. Ta c c bng v mt bng xy dng hm sy nh sau: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 29 Vi kt cu xy dng nh trn, tc ca tc nhn sy nng i trong knh dn vo khong 2,5m/s. Tc ny l hp l gim tn tht p sut cho qut. Trn nn ca hm c lp 2 thanh ray xe gong c th di chuyn t do dc theo hm sy. B QU TRNH SY THC 4.5 Tng cc tn tht nhit trong h thng sy Khi vn hnh lm vic hm sy tn tht ca HST bao gm cc tn tht sau: -Tn tht do vt liu sy mang i: Qv [kJ/h]; qv [kJ/kg_m]. -Tn tht do thit b truyn ti (khay sy, xe gong): QTBTT [kJ/h]; qTBTT [kJ/kg_m]. -Tn tht do mi trng ca kt cu bao che: QMT [kJ/h]; qMT [kJ/kg_m]. Ta ln lt xc nh cc tn tht ny nh sau: 4.5.1 Tn tht nhit do vt liu sy mang i qv[kJ/kg_m] Theo kinh nghim vn hnh h thng vi sn phm sy l nng sn thc phm th sn phm sy (SPS) i ra khi thit b sy (TBS) c nhit thp hn nhit ca TNS i vo t 510oC. Do , VLS i ra c nhit l tv2=70oC 10oC =60 oC. Nhit VLS i vo ng bng nhit mi trng tv1=27 oC. Nhit dung ring ca Chui l CVL=1,0269 kJ/kg.K, nhit dung ring ca nc l 4,18 kJ/kg.K vi sn phm u ra l Chui kh c m W2=12%, do nhit dung ring ca Chui i ra khi hm sy l: CV2= CVL.(1W2)+Cn.W2=1,0269(1-0,12)+4,18.0,121,4 kJ/kg.K Do vy, tn tht nhit do sn phm sy mang i l: QVL=G2.CV2.(tv2tv1)=45,45.1,4.(7027) = 2736,09 kJ/h
3.5.2 Tn tht nhit do thit b truyn ti qTBTT [kJ/kg_m] Ta c: QTBTT = Qkh + Qx. Vi Qkh v Qx ln lt l tn tht do khay sy v xe gong mang i. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 30 Nhit ca khay sy v xe gong khi i vo hm sy ly bng nhit mi trng l: tkh1 = tx1 = to = 27. Nhit ca khay sy khay sy v xe gong khi i ra khi khay sy ly bng nhit sy : tkh2 = tx2 = t1 = 80. Khay sy v xe gong c khi lng ln lt l: Gkh = 4kg; Gx = 28kg. Nhit dung ring ca vt liu ch to xe v khay (Inox v Nhm) l: Ckh = 0,86 kJ/kg.K ; Cx= 0,42 kJ/kg.K. -Tn tht nhit do khay sy mang i l: Vi s lng khay l Nkh=160 khay; Thi gian sy l
-Tn tht nhit do xe gong mang i l: Vi s lng xe l Nx = 10 xe. Thi gian sy lTa c:
Do vy tng tn tht nhit do thit b truyn ti mang i l: QTBTT = Qkh + Qx = + 779,1= 4425,5kJ/h qTBTT =
=
4.5.3 Tn tht nhit qua kt cu bao che qMT[kJ/kg_m] Vi kt cu xy dng ca hm sy nh thit k ta c: Tit din t do ca tc nhn sy nng i trong hm l: Ftd = FH + FX. Vi FX: l tit din ca xe gong (4thanh thng ng 25 1740), 12 thanh nm ngang 251200), do FX = 4.(0,025 1,74) + 16.(0,025 1,2) = 0,654m2. FH: l tit din ca hm sy (1870 1890), do FH = 1,87 1,893,5343 m2. Vvytitdintdol:Ftd=3,53430,654=2,8803m2.Saukhitnhtonqu trnh sy l thuyt ta xc inh c lu lng tc nhn sy i qua hm l: Vlt = 11380,5m3/h=3,16m3/s,tuynhintrongqutrnhsythcthlngTNSny phi ln hn b li cc tn tht. Do , tc TNS ti thiu i trong hm sy l: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 31
ta s kim tra li gi thit ny. Tnthtdoktcubaochephthucvoktcuxydngcahmsyvbao gm cc thnh phn sau: -Tn tht qua 2 tng bn: QT. -Tn tht qua trn: QTr. -Tn tht qua nn: Qn. -Tn tht qua 2 ca vo v ra ca hm: Qc. Do , QMT = QT + QTr + Qn + Qc 4.5.3.1 Tn tht qua 2 tng bn: QT V lu lng tc nhn sy ti thiu trong qu trnh sy thc phi ln hn lu lng tc nhn sy trong qu trnh sy l thuyt nn tc tc nhn sygi thit tnh ton cc tn tht cng phi ln hn vlt. Gi s ta ly v = 1,2 m/s. Ta c: 1= 6,15 + 4,17v = 6,15 + 4,17 1,2 = 11,154 W/m2. Bng phng php lp gi thuyt trc nhit tng pha trong tw1 v tnh cdngnhitqtruynquatng.Tdngnhitnytatmcnhitmt truyn nhit bng i lu gia tc nhn vi tng trong q v dng nhit truyn t mtngoicatngvomitrngqsaikhcnhaukhngqu10%thktqu tnh ton l chp nhn c. Ta gi thit tw1 = 59,5oC. Ta c: q = 1(tTBtw1) (cng thc 6.11, trang 74, [8] Vi:
Vy q= 11,154(65 59,5) = 61,347 W/m2 Nhit mt ngoi ca tng tw2, theo h qu ca nh lut Furier ta c:
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 32 y 1 l h s dn nhit ca gch, 1= 0,77 W/m2. ( tra bng I.126, trang 128, [9]). 1 l b dy ca tng 1= 0,2m. V vy
Nh chnh lch nhit t = tw2 to = 43,56 27 = 16,56oC Nhit tnh
T nhit tm = 35,3 tra bng I.255, trang 318, [9], ta c: 1= 2,73.10-2 W/m. = 16,48. 10-6 m2/s Pr= 0,7 Do , chun s Gratkov (cng thc V.39, trang 13, [10]):
Vi h s gin n th tch:
g l gia tc trng trng g = 9,81m/s l = H l chiu cao ph b, H + Tr + bng = 1,89 + 0,15 + 0,1= 2,14m
Chun s Nuyxen (cng thc V.68, trang 23, [10]): Nu = C(Gr.Pr)n H s C v n ph thuc vo tch s Gr.Pr Gr.Pr = 2,02.1010 0,7 = 1,417.1010 > 2. 107 (ch xoy) Nn ta xc nh c C=0,135; n = 0,33 Nu = 0,135(Gr.Pr)0,33 = 0,135(1,417.1010)0,33 = 302,2 H s trao i nhit i lu n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 33
(cng thc trang 23, [10]) Dng nhit truyn t b mt ngoi ca tng vo mi trng: q= 2 (tw2 to) = 3,855(43,56-27)=63,84 W/m2 Sai s gia q v q:
Vi qmax=q=63,84oC. Sai s ny nm trong phm vi cho php. Tng bn c kch thc l: Ft=(Hh.Lh).2= (1,89.14).2=53m2 Tngcxybnggchdyt=200mm=0,2m,chsdnnhitt=0,77 W/m. (tra bng I.126, trang 128, [9]). Ta xc nh c:
Do tn tht qua 2 tng bn Qt bng: Qt= Ft.kt(ttb - to) =53.1,79(65 - 27) = 3605,06W 4.5.3.2 Tn tht qua trn QTr Trn c kch thc FTr= Bh.Lh = 1,87.14= 26,2m2 Trncbngbtngctthpdy2 =150mm=0,15mvbcthm1lp bngthytinhcchnhitcbdy3 =100mm=0,1m.TrabngI.126,trang 128, [9]) ta c h s dn nhit ca b tng ct thp v bng thy tinh cch nhit lm lt l: 2=1,55 W/m. v 3=0,06 W/m.. Ta xc nh c:
Do tn tht qua trn QTr bng QTr= Ftr.ktr(ttb - to) =26,2.0,5(65 - 27) = 495,7W 4.5.3.3 Tn tht qua nn: Qn Nn c kch thc Fn= Bh.Lh = 1,87.14= 26,2m2 n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 34 Nhit trung bnh ca tc nhn sy bng 65oC v gi s phng cy cch tng bao che phn xng 2 mt. Theo bng 6.1, trang 74, [8]), ta c: qn= 40W/m.Do tn tht qua nn bng: Qn= Fn.qn=26,2.40=1048W 4.5.3.4 Tn tht qua 2 ca vo v ra ca hm sy: Qc 2phauvovracahmsyclpcavikchthc:13001850(mm). Nn din tch ca ca l: Fc= 2(1,87.1,89)=7,0686 m2 Ca c lm bng thp dy c = 10mm = 0,01m. Tra bng I.126, trang 128, [9]), ta c h s dn nhit ca ca l: c = 0,5 W/m.. Ta xc nh c:
Do Qc= Fc.qc=7,0686.3,147.(65 27) = 845,31W Nh vy tng cc tn tht nhit ca cc h thng sy qua kt cu bao che l: QMT = QT+QTr+Qn+Qc= 3605,06+495,7+1048+845,31= 5723,9W = 5994,073,6 kJ/h = 21578,65 kJ/h
V vy tng cc tn tht ca h thng sy l: = Ca.to qvl qTBTT qMTViCa.to thnh phn nhit vt l do TNS a vo, thay vo ta c tng tn tht ca h thng sy l: = 4,18.27 60,2 30,43 148,26 = -126,03 kJ/kg_m Vi tvl = to = 27oC 4.6 Tnh ton qu trnh sy thc Ta ln lt xc nh cc thng s ca tc nhn sy cc im nt trong qu trnh sy thc nh sau: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 35 4.6.1 Thng s ca khng kh sau thit b sy (thng s khng kh thi ra ngoi, cng nh khng kh hi lu ti bung ha trn) (2t) cha hi ca khng kh ra khi thit b sy l: - cha hi sau qu trnh sy thc:
(Cng thc 5.36, trang 65, [8]) Trc ht ta tnh: i1= r + Cpa.t1 = 2500 + 1,842.80 = 2647,36 kJ/kg_kkk i2= r + Cpa.t2 = 2500 + 1,842.50 = 2592,1 kJ/kg_kkk Thay vo vi: t1=80 oC, t2=50 oC, do=0,0185kg_m/kg_kkk, n=1, = -119,34 kJ/kg_m Ta c:
Entapi ca khng kh ra khi thit b sy l: I2t = 1,004t2 + d2t(2500 + 1,842t2) = 1,004.50 + 0,041(2500 + 1,842.50) = 156,476 kJ/kg_kkk Phnpsutbohacahincnhitt2=50oCtrabng3,trang 192, [1] ta c: pbh2=0,12335 bar m tng i ca khng kh ra khi thit b sy:
So vi iu kin chn 2 = (51,55%) l hon ton tha mn. Nh vy, chn t2=50 oC l hp l. Nh vy, khng kh ra khi thit b sy (2t) ta c: t2t=50 oC, 2 = 50,4%, d2t=0,041 kg_m/kg_kkk, I2t=156,476 kJ/kg_kkk. 4.6.2 Thng s ca khng kh sau bung trn (Mt) Khng kh sau bung trn l trng thi im (Mt) c: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 36 cha hi ca khng kh sau bung trn l:
Entapi ca khng kh sau bung ha trn l:
(cng thc 5.32, trang 65, [8]) Nhit ca khng kh sau bung ha trn l:
(cng thc 5.33, trang 65, [8]). PhnpsutbohacahincnhittMt=38,7oCl pbhM=0,0737 bar (tra bng 3, trang 192, [1]). m tng i ca khng kh sau bung ha trn
Nhvykhngkhsaubunghatrn(M)c:tMt=38,7oC,Mt=, dMt=kg_m/kg_kkk, IMt 115,373 kJ/kg_kkk. 4.6.3 Thng s khng kh sau khi ra khi Calorifer (i vo thit b sy) (1t) Khng kh sau khi ra khi Calorifer i vo thit b sy l trng thi im (1t) c: cha hi ca khng kh sau khi ra khi Calorifer l: d1t = dMt= 0,02975 kg_m/kg_kkk Entapi ca khng kh sau khi ra khi Calorifer l: I1t = 1,004t1t + d1t(2500 + 1,842 t1t) = 1,004.80 + 0,02975(2500 + 1,842.80)= 159,08 kJ/kg_kkk Phnpsutbohacahincnhitt1t=80oCl pbh1=0,4736bar (tra bng 3, trang 192, [1]). m tng i ca khng kh sau khi ra khi Calorifer l:
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 37
Nh vy khng sau khi ra khi Calorifer i vo thit b sy (1t) c: t1t=80oC,
1t= , d1t=kg_m/kg_kkk, I1t 159,08kJ/kg_kkk. 4.7 Lu lng khng kh kh thc t cn dng 4.7.1 Lng khng kh kh thc t lu chuyn trong thit b sy
(cng thc 5.17, trang 61, [8]). Vi nhit trung bnh ca dng kh lu chuyn trong thit b sy l: ttb = 0,5(t1+ t2) = 0,5(80+ 50)= 65oC tb= 1,044kg_kkk/m3_kkk (tra bng I.225, trang 318, [9]). Do , lu lng th tch khng kh lu chuyn qua thit b sy l:
Do , tc ca tc nhn sy trong bung sy trong qu trnh sy thc l:
Saikhcvitcgithit1,2m/skhngnhiu(khong1%)nntachp nhn kt qu ny. 4.7.2 Lng khng kh kh ngoi tri thc t cp vo cn thit
Vi nhit ca khng kh ngoi tri l:to=27oC = =1,176 kg_kkk/m3_kkk (tra bng I.225, trang 318, [9]). Do , lu lng th tch khng kh cp vo cn thit l:
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 38 4.8 Nhit lng cn cung cp cho tc nhn sy t Calorifer Nhit lng cn cung cp cho h thng sy (cung cp qua calorifer kh hi) l:
Q= W.q= 145,55.3885,07= 565471,45 kJ/h 157kW Nhit lng c ch q1: q1= i2 Ca tv1 = 2592,1 - 4,18.27= 2479,24 kJ/kg_m Tn tht nhit do tc nhn sy mang i q2:
Vi Cdx(d0)= Cpk+ Cpad0=1,004 + 1,842.0,0186= 1,0383 kJ/kg.
Tng nhit lng c ch v cc tn tht q: q= q1 + q2 + qvl + qTBTT + qMT
= 2479,24 + 1043,27 + 18,81 + 30,43+= 3720,01 kJ/kg_m C th thy rng nhit lng tiu hao q , tng nhit lng c ch v cc tn tht q phi bng nhau. Tuy nhin trong qu trnh tnh ton chng ta lm trn hoc sai s trong tnh ton cc tn tht m chng ta phm phi mt sai s no . Chng ta kim tra sai s ny. y sai s tuyt i:q = q q = 3885,07 3720,01 = 165,06 Hay sai s:
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 39 Bng 5.1 cn bng nhit ca h thng sy: STTi lng K hiu Gi tr [kJ/kg_m] % 1Nhit lng c chq12479,2466,64 2Tn tht do tc nhn syq21043,2728,04 3Tn tht do vt liu syqvl18,810,5 4Tn tht do thit btruyn tiqTBTT30,430,82 5Tn tht ra mi trngqMT148,263,98 6Tng nhit lng tnh tonq3720,01100 7Tng nhit lng tiu haoq3885,07100 8Sai s tuyt i4,2 Nhn xt: Qua bng cn bng nhit ta nhn thy tn tht nhit do vt liu sy mang i ch chim mt phn r nh (khong 0,5%), tn tht ra mi trng v thit b truyn ti cng chim khng ng k so vi tng tn tht. Tn tht ch ch yu l do vt liu sy mang i. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 40 CHNG 5. TNH TON CC THIT B PH THIT K CALORIFER - CHN QUT 5.1. Tnh ton thit k calorifer Vi nng lng cung cp l hi nc bo ha do ta s thit k mt calorife kiukhhingcnh.VincbohangngtrongngvTNSlkhngkh nng chuyn ng bn ngoi ca cc chm ng nhn nhit t c nhit yu cu. 5.1.1 Cc thng s c bn yu cu thit k calorifer Vi yu cu ca HTS cn nng nhit ca tc nhn sy sau im ha trn M t
ln n
, do vy m bo yu cu t ra ta chn nhit ca hi bo ha l
Do nhit ngng t l:
p sut ngng t l:
Vi cng sut nhit ca calorifer yu cu trong qu trnh tnhton sy thc trn ta c
. Coi hiu sut ca calorifer l 90%(10% cn li l tn tht dobm bi, vt liu chto lu ngyb nmn ),do vycng sut nhit m hi nc cn truyn cho TNS l:
Nhit m ngng t ca hi nc nhit ngng
l r=2257kJ/kg Lng hi vo calorifer yu cu l:
5.1.2 Tnh ton thit k calorifer: a)Tnh din tch trao i nhit F ca calorifer: Chn ng thp dn hi c
ng xp so le vi ng bc ngang.
, bc ng dc l
. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 41 Chn cnh c lm t ng Cnh c lm bng ng c h s dn nhit
. Chiudycnhlyl
.ngknhcnhl
.Bc cnh l
Nhitlmvicchophptiacacnhng250oC(phn3,trang36, [3]). Docnhclmtngnnngsutchophpcangctnhtheo2 cng thc sau: []
(cng thc 1 4, trang 13, [4]). []
(cng thc 1 3, trang 13, [4]). Hsantonl:
;
;
;
(bng1-6,trang 15, [4]). H s hiu chnh kim tra bn l: []
(cng thc 1 9, trang 17, [4]). Ly . Gii hn nng chy l
(bng 2-17, trang 38, [4]). Vy[]
[]
H s mi hn ca cnh v ng l: h = 0,95 (bng 1-8, trang 19, [4]). Ta cn xc nh din tch b mt ngoi cc ng c cnh l
Vi
.
. Do t s : n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 42
V vy ta phi tnh chnh nhit trung bnh logarit nh sau:
.H strao i nhit vi din tch mt ngoi c cnh
c tnh khi b qua nhit tr dn nhit ca vch ng (
l:
Trong
l h s lm cnh, vi cnh trn th c xc nh qua biu thc:
lhstraoinhitilucahingngvibmttrongcang c xc nh qua biu thc sau:
(
)
Vi hi nc bo ha ngng nhit
. Ta c nhng thng s vt l ca nc ngng bo ha nh sau:
,
r = 225kJ/kg,
.
:L chnh nhit gia hi ngng vi nhit vch trong cang,do
rtlnnn
rtnh.Tagithit
(sautaphi kim tra li gi thit ny). C:
(
)
:H s ta nhit ca khng kh bn ngoi ng c tnh qua biu thc
. Vi
l h s ta nhit ca khng kh vi cnh, c xc nh qua biu thc:
(
)
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 43 -Do ng b tr so le nn h s C ly bng C=0,45. -Tiu chun Reynoild c xc nh qua:
Tc khng kh ti khe hp ca cnh c xc nh qua biu thc:
*
+ Tc ca TNS (khng kh) i vo calorifer l
Thay vo ta xc nh c:
[
]
Vi nhit trung bnh ca khng kh qua calorifer :
Tatraracccthngsvtlca khng kh nh sau:
Do vy:
-
: L din tch b mt ng trn khng cnh vi chiu di 0,6m:
S cnh trn chiu di 0,6m ng c l:
Din tch phn ng trn khng ph cnh l:
n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 44 Din tch cnh:
(
)
(
)
Tng din tch b mt trao i nhit ca ng vi dng khng kh chuyn ng ct ngang qua l:
. V vy l h s ta nhit ca khng kh vi cnh l:
(
)
L h s hiu qu lm cnh:
T s:
Hiu sut cnh
c tra trn th theo
v tch s vi:
Tra ra ta c
. Do vy:
.
Takimtraligithuytv
do
phithamn
coi
nn ta c:
(sai lch so vi
khng nhiu nn ta chp nhn kt qu ny). H s trao i nhit vi din tch mt ngoi c cnh
c tnh khi b qua nhit tr dn nhit ca vch ng (
l: n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 45
Khiktibmbibncnhcngnhngcncahincbntrong ng ta c h s trao i nhit tnh vi h s bm bnl:
Do vy din tch trao i nhit b mt ngoi ca cnh l:
Din tch trao i nhit b mt trong ca cc ng l:
b) Tnh thit k kch thc hnh hc ca Calorifer: Vi chiu cao ng hay chiu di ng chn trn l H = l = 0,6mta c tng s cc ng n l:
Vi s ng l 227 ng c sp xp trong thit b hnh tr trn nn c sp xp trn v ng hnh ch nht vi chiu di l 16 ng chiu rng l 15 ngKch thc hnh hc ca v hnh ch nht Di =D= 16.49=784 mm Rng =R= 15.49=735 mm Thnthitbhnhtrnctmnmtrngiao2ngchocavhnhch nht nn tnh c ng knh hnh trn l 1060mm Tnh chiu di thn thit b: Dt = 1060 mm; Hng = 600 mm.
ng sut cho php tiu chun ca thp CT3 c: []
(Hnh 1-1, trang 15,[4]). ng sut cho php l: [] []
(cng thc 1 9, trang 17, [4]). n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 46 []
B dy ti thiu ca thn l:
[]
(cng thc 5-3, trang 96, [4]). Chn h s b sung quy trn kch thc C0 = 0,8mm. Tng h s b sung vi Cc = 0 l:
(cng thc 1-10, trang 20, [4]). B dy thc ca thn thit b :
Kim tra iu kin:
(cng thc 5-12, trang 97, [4]). Kim tra p sut cho php trong thn thit b: [] []
(cng thc 5-11, trang 97, [4]). Vy b dy thn l 2mmDothitblmvicpsutkhquynviukinlmvicbnhthng nn ta ly b dy ca thn, np v y l bng nhau v bng 2mm c)Tnhtontnthtpsut(trlc)cadngkhngkh(TNS)chuynngct ngang qua Calorifer: Tr lc ca khng kh bao gm tr lc ma st v tr lc cc b c tnh gn ng theo quan h sau:
Trong : Z: S hng ng, y Z = 15 Tc ca dng khng kh qua khe hp ca Calorifer, y7m/s. n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 47 Khi lng ring ca khng kh, y
. H s tr lc, vi chm ng sole c xc nh gn ng qua biu thc sau:
(
)
(
)
(
)
(
)
(
)
(
)
Thay vo ta c:
5.2. Qut Qutlbphnvnchuynkhngkhvtopsutchodngkhiquacc thit b: calorifer, my sy, ng ng, cyclon. Nng lng do qut to ra cung cp cho dng kh mt p sut ng hc di chuyn v mt phn khc phc tr lc trn ng ng vn chuyn. Nng sut ca qut c c trng bi th tch kh i vo hay i ra thit b sy. 5.2.1. Tnh tr lc: 5.2.1.1. Tr lc t ming qut n calorifer Chn ng ni t qut n caloriphe c ng knh l 0,38 m, di 2m. -Vn tc kh i trong ng l:
Ta c (kg/m3) tM = 38,70C F =1134 , 0438 , 0 14 , 342 2==d t( m2) L = 12937,78 (Kg/h) Vy n qu trnh v thit b - Tnh ton thit k h thng sy chui GVHD:Nguyn Th Xun MaiTrang 48
Chun s Reynol l :
(cng thc II.4, trang 359, [9])
=khngkhitrongngtheochchy xoy[9]. -Chuyn ng chy xoy chia lm 3 khu vc:+Vng 1: nhn thu lc hc; khu vc ny nhm khng nh hng n h s ma st
(
)
(
)
(cng thc II.60, trang 378, [9]) c =104 : nhm tuyt i ca ng (bng II.15, trang 381, [9]) +Khu vc 2: khu vc nhm; khu vc ny h s ma st ph thuc vo nhm m khng ph thuc vo chun s Reynol:
(
)
(
)
Vy Regh104:Vy khng kh chuyn ng theo ch xoy T s 0565 , 02113 , 02= =tFF Tra [9] (trang 388), ta c:045 , 0 = Vy tr lc do t thu calorifer l: 88 , 22224= = AkkPe (N/m2) 5.2.1.5. Tr lc ng ng dn khng kh t caloriphe n phng syChn ng ng di 1,5(m) ng knh ng d= 0,38 (m) Tnh ton ging ng t ming qut n caloriphe ta c: Regh