HE TH6NG NGHIDN M!N TRONG DAY CHUYDN CHE BI^N THCKC A N C H O THCIY SAN NANG SUAT 0,5 - 0,6 T/H - GIAI PHAP VA K^T QUA DAT DU'OC Nguyin Nang Nhu'9'ng, Ph?m Ngpe Tuyen, TrSn Van D^t Wfn Co di^n Ndng nghidp va Cdng ngh^ Sau thu hoach Tom tat Thuc dn cho thuy sdn cd yeu cdu rdt khdt khe ve chdt lugrng, dgc bi?t dgc thii cho dn dudi vdphdi chi biin theo cdng ngh4 ep dim vdy dp nho ciia nguyen lieu dua vdo mdy ep dim ph ndm khodng 100-300 pm tiiy logi thdc dn Mat khdc thdnh phdn nguyen lieu dua vdo c bien thirc dn cho thuy sdn tuang ty nhu cdc logi thirc dn chan nudi khdc la tinh chdt ca ly khd ddng nhdt, nhieu logi nguyen lieu chira nhieu sa Do vgy de nghien dgt dp nhd yeu cdu Id cdng khd vd doi hdi chi phi ndng hrang ldn Ket qud nghien cieu dd lua chon duac nguyen ly nghie sdng phdn logi de nghien nhd nguyen lieu che bien thirc dn cho thiiy sdn ndng sudt 0,5 -0,6 T Dp nhd sdn phdm phdn tich qua sdng Id 300 pm dgt 94,7%, ddp img du^c yeu cdu cdu cdng n chi biin thuc dn cho thuy sdn Chi phi ndng lieang cho he thdn^ thdp (54,1 kW.h/T) chi hdng khodng 50% chi phi ndng luang rieng cho cdng dogn nghiin hai ldn thd vd mfn He thdng ldm dn dfnh, de thao tde, vgn hdnh Tie khoa: He thong nghien mm, thiec dn thiiy sdn I OAT VAN De Do ddc thft cho an dudi nudc vd phdi cd dugc cac lo?i thfte dn cd thl ndi, la limg hodc chim, vdy thudng phdi chl biln theo cdng ngh? dp dim vd dl dap ftng dugc yeu cdu k^ thudt, dp nhd cua nguyen lieu dua vdo may ep dim phdi ndm khodng 100 - 300 |im tiiy loai thfte dn Mdt khdc nguyen lieu dung dl chl biln thfte an cho thiiy sdn vl thdnh phdn ca bdn gidng nhu thfte dn ehdn nudi thdng thudng, nhun^ vl ty le thi khdc nhau, thupe chftng lo^i thfte an cdri sdn xudt Do tinh chat ca ly khdng ddng nhdt, nhilu loai nguyen lieu chfta nhilu sa, nen dl nghiin dat dp nhd yeu cdu la cdng viec khd vd ddi hdi chi phi ndng lugng ldn Quy trinh cdng nghe chl biln thfte an cho thfty sdn ndi chung vd cho ca cdc loai ndi rieng nhin chung van nhu quy trinh chl biln thfte dn gia sue Id chl biln theo me vd qua cac cdng doan chinh: nghiin nhd -* cdn djnh lugng theo ty 1? da dinh -^ phoi trdn -^ ep tao vien -^ cdn ddng bao sdn phdm hodc can djnh lugng theo ty 1? da dinh -> nghiin nhd ^ phdi trdn -> ep lao vien -• cdn ddng bao sdn pham Dilu khdc ca bdn cdng nghe sdn chl biln thfte dn cho thfty sdn vd cho gia sue la yeu cdu ky thudt cy thl d cdc cdng doan nhu dp nghiin nhd, ddng dlu sau trpn, kich thudc, ty trpng cfta vien vd chdt lugng cua vien, ty 1? bd sung ddu beo v.v Tong thl yeu cdu ky thudt cua cdc cdng doan quy trinh chl biln thfte an cho thfty sdn deu cao han vd khdt khe ban so vdi yeu cdu chl biln thfte an cho gia siic Hien d Viet Nam nhu cau thfte dn cho thuy sdn rat Idm va ngdy mpt tdng nhung vl cdng nghe vd thilt bi chua dugc nghien cftu mdt cdch bdi bdn, nhat Id d quy md vfta vd nhd Do vdy thilt kl, chl tao dugc d nudc he thong nghiin mjn nang suat 0,5 - (),6 tdn/gid dung day chuyin chl biln thuc dn cho thuy san, dam bdo dp nhd, dam bdo chdt lugng, phft hgp vdi dieu kien sdn xudt o Viet Nam Id cdp thilt 107 II NOI DUNG VA PHU'aNG PHAP NGHIEN CU'U 2.1 Noi dung nghien cu'u Dieu tra, khdo sdt thuc trang va yeu cdu ddi vdi thfte an cho thfty san ndi chung vd cho cd ndi rieng hien dang sft dyng san xudt, ldm ca sd cho viec chgn cdng ngh? vd thilt bj; Tim hieu, khdo sat cdng nghe va thiet hi nghien mia dung cdc day chuyen che biln thfte an cho thuy san tren the gidi, nhdt Id cdc day chuyen hien dang sft dyng d Viet Nam lam co sd cho viec chpn nguyen ly, ket cau cdc mdy he thdng nghien nghien cftu; Lya chpn nguyen ly, ket cau cho cdc may chinh he thdng gdm: mdy nghien min; he thdng hut, van chuyen vd tdch Ipc san phdm nghien; sang phdn loai sdn pham; Thiet ke, che tao he thdng thiet bi tren; Thft nghiem, danh gia kha ndng Idm viec cfta cdc mdu may nghien cftu vd loan bd he thong 2.2 Phu'O'ng phap nghien CLPU Trong nghien cftu da sft dyng cdc phuomg phdp sau: - Phuomg phdp dieu tra, khao sat vd xft Iy thdng tin thu dugc; - Phuomg phdp chuyen gia dk lua chpn nguyen ly, kit cdu cdc may, nhdt Id sang phdn loai; - Phuomg phap thi nghiem: + Phuomg phdp cdng sudt khdng tdi va cd tdi cua cdc thilt hi chinh bdng thilt hi cdng sudt chuyen dyng; + Phuomg phap do, xdc dinh nang sudt cua cac may: nghiin, sang phdn loai; + Phuomg phdp ddnh gia chat lugng bdt sau nghiin va sau phdn loai; + Cdc phuang phdp xft Iy sd lieu thi nghiem thu dugc III K^T QUA vA T H A O L U A N 3.1 Lira chon nguyen ly he thdng Tren ca sd tim hilu, khao sat cdng ngh? vd he thdng thilt bi nghiin niin dftng cac day chuyen che bien thfte an cho thuy sdn tren thl gidi vd d Viet Nam, da lua chpn dugc nguyen Iy, ket cdu cac mdy he thong nghiin nghien cftu (hinh 1) Hinh Sa d6 quy trinh cong ngh# nghign mjn d l xult nghign ci>u - Giu tai cap li#u; - Thiing chu-a tren nghign; - Co clu d p li^u vao mSy nghiin; - Mdy nghiin bua; - Qugt hut; - Thiet bj IQC bpt tay ao; - Sang phan logi; - Hg thong due^ng 6ng; - Mdy n6n 108 Qiiy trinh nghiin Id chu trinh kin nghiin nhd kit hgp vdi sang phdn loai Hat nhd dat tieu chuan dua sang cdng doan tilp theo, hat to dua quay trd lai may nghiin dk lam nhd tilp Ldy, van chuyen sdn phdm sau nghiin dua len sdng bdng he thdng gid dp lyc cao kit hgp vdi giu bui ty ddng Dp nhd sdn phdm hieu chinh thdng qua mdt sdng phdn loai rieng biet ben ngodi may nghien bdng each thay cdc ludi sdng phu hgp 3.2 Cc SO" khoa hoc lya chpn cac thong s6 chinh cho cac may 3.2.1 May nghiin Nguyen lieu dua vdo nghiin eac ddy truyin chl biln thfte an chan nudi (TACN) ndi chung vd thfte an cho thfty sdn ndi rieng d Viet Nam chft ylu Id ngd, khd ddu ddu tuomg chill ly, khd ddu lac, sdn lat khd_, bdt cd, xuomg ddng vdl, mudi an ndi chimg phdn ldn la loai gidn, de nghien, vdy de cd mau may nghien ldm viec hieu qud cdn tang tdi mftc ldi da cd thl dugc gde dm cfta sang dl tang khd nang thodt cho nguyen lieu da dat du dp nhd cdn thilt, ddng thai cd gidi phdp gidm van tde luu chuyen cfta ldp nguyen lieu budng nghiin Ddp ftng dugc cdc yeu cdu tren la may nghien cd budng nghiin dang hinh gipt nudc Tuy nhien d ddy cdn phdi nghiin vdy phdi tinh loan lua chpn van ldc ddu bfta, khe hd gifta bfta vd sdng vd tinh kiim tra cdn bdng lai cho bua nghiin cftng roto nghiin, ddm bao cho may nghiin ldm viec dat hieu sudt cao v l nang sudt cfta mdy nghiin, de bdo ddm ndng sudt trung binh cfta he thdng Id 0,5 - 0,6 tdn/h, nang sudt Iy thuyit cfta mdy nghiin phdi dat 0,8 - 0,9 tan/h vi day Id nang sudt thudn vd phdi nghien di nghien lai a Van tde ddu bua Van tde bua thudng dugc xdc dinh bdng thyc nghiem, tinh loan nhung ket qud chu yeu Id de tham khdo Thdng thudng van tde dau bua ciia may nghien TACN Id 65-75 m/s Ngdy vdi cdng nghe che tao mdt hodn thien, nhieu mdy nghien da dat van ldc ddu bua 100 - 115 m/s [4; 9] Neu chi nhin tft hieu qud dap thi van tde biia cdng cao, hieu qud dap cdng ldn vd thdi gian nguyen lieu nam budng nghien cdng nhd Nhumg chpn van ldc ddu bua phii hgp, can quan tdm den nhieu yeu td, dd cd yeu td chi phi nang lupmg Ta biet rdng ldng van tde dau bfta dong nghia vdi viec tang chi phi ndng lupmg chay khdng tdi len ba ldn Vi dy tdng van tde ddu bfta tft 55 len 115 m/s, chi phi ndng lupmg cho qud trinh nghien gidm 21%, mftc dp nghidn tang 110% vd cdng sudt chay khdng tdi ldng 75% [9] Ngodi tdng ldc dp cfta roto nghiin can ddc biet chu y din cdn bdng ddng cho roto dl gidm dp rung cho mdy Tren ca sd cdc phdn tich tren vd tham khdo cdc may nghien cfta nudc ngodi chpn van ldc ddu bfta 85 m/s cho mau mdy nghien cftu vfta bao dam hieu sudt nghien, vfta phft hgp vdi khd ndng che tao d nudc b Kich thu&c roto - Dudng kinh roto r ^30V D =2 (1) 7i.n Trong do: D - Dudng kinh roto, m; V - Van tde ddu biia, m/s; n - Toe quay cfta roto, v/ph Vi roto nhdn chuyin ddng true tilp tft ddng ca dien cd ldc dp quay 2960 v/ph Thay cac gid tri vdo (1) tinh dugc D = 0,5487 mm Chpn D = 550nim - B I rpng roto nghiin Ndng sudt may nghien cd the tich theo cdng thfte thuc nghiem sau [9] 109 (2) Q = (2-8)10^p.D^Bco Trong dd:Q- Nang sudt may nghiin, kg/s; B - B I rdng roto, m; CO - Van ldc quay, rad/s; p - Khdi lugng rieng nguyen lieu nghien, kg/m Tft (3.2) ta cd bl rdng roto: (3) (2H-8).yO.D'.fi> May cd nang suat cang ldn chpn he sd (2j8) cdng cao Doi vdi may nang suat 0,8 - 0,9 tdn/h (vdi sang Io 0,8 mm) tftc Q = 0,236 kg/s, bl rdng roto Id: B= 10'.0,236 • = 0,252 m 2.500.(0,55)^309,8 Dl phft hgp vdi cac ddng may nghiin hien dang sft dyng phd biln san xudt chpn: B = 270 mm c Chpn kich thu&c bua nghiin vd bdn kinh chdt treo bua Bfta nghiin duac treo vdo dia roto thdng qua khdp ban ll Trong qud trinh lam viec, dudi tac dyng cfta luc ly tam, luc va dap, bfta ludn cd xu thl lech di vd quay trd lai vi tri can bdng Hinh la sa db Iam viec vd cdc sung luc tac ddng len bfta qua trinh nghien Jc r^ _-:_ /"^ LP"" vl/ c a/2 a Hinh So dd lam viec cua bua budng nghign NIU thod man dilu kien [1; 4; 6; 9]: /^ = c.l (4) Trong do: p Id bdn kinh qudn tinh cfta bua ddi vdi chot treo; c - Khodng each tft chdt treo din trpng tdm bua; / - Khoang each tft chdt treo den ddu va dap cfta bua Thi bfta dugc coi la can bdng qua trinh dap Tftc sung luc tft bua khdng chuyen vao din true va d bi Bd qua dien tich Id, vdi bfta hinh chft nhdt chieu ddi la a, chieu rdng la b, ta cd: PI 110 a'+b' 12 (5) Trong dd po - Bdn kinh quan tinh vdi frpng tdm bua Matkhactacd[4]: = pQ+c- = p =p^+c'=— - + c' (6) Ndu va dap xdy d ddu bfta l=c+— Thay (6), (7) vdo (4) ta cd: a^+b^ Sau nit gpn cd: (7) ( « +c =c c+— 12 I a +b 6a Nhu vdy de bao ddm can bang qua trinh lam viec, cdc kich thudc cfta bua phdi thod man dieu kien (8) Thuc te dl bdo dam che dp ldm viec dn dinh cho mdy nghiin, kich thudc cfta bfta cdn dugc chpn phft hgp vdi dudmg kinh roto nghiin Ngoai dieu kien (8), roto va bfta nghien dugc coi Id cdn bdng ddng lyc hpc neu thod man dilu kidn [4; 6; 9]: c= Hay / = 0,154 D Vi da chpn D = 550 mm, vdy kich thudc cua bfta (hinh 2) Id: / =0,154x550 =84,7 mm Chpn a =120,b = 50 120'+50' (10) ^^ ,^ = 23,47mm Vdv c= •^ 6.120 Lam trdn so, kich thudc cua bfta Id: a = 120 mm b = 50 mm / = 85 mm c = 25 mm Bdn kinh chdt treo bfta: Tft (10) sau thay D = 2(Rt +1) vd rut gpn ta cd: RT = 2,251 = 2,25 x 85 = 191,25 mm Lam trdn sd: Rt =190 mm d Cdng sudt tiiu thu D I xdc dinh cdng suat lieu thy cho mau mdy nghiin nghien cftu Cdng suat tieu thy cfta may nghiin dugc tinh theo cdng thfte: N = Nngh+NLC + NKT (11) Trong do: Nngh - Cdng suit tieu thy cho qud trinh lam nhd nguyen lieu nghiin, W; NLC - Cdng suat tieu hao lam luu chuyin khdi nguyen lieufrongbudng nghiin, W; NKT - Cong sudt chay khdng tdi, W Ul Cdng sudt tieu thy cho qua trinh ldm nhd nguyen lieu [6; 9]: da Qv^ N„„h = -^(o — = —— (12) "'" dt \-f Trong do:] - Mdmen quan tinh cfta roto, kg.m ; CO-Van tde gde, s~'; Q - Ndng sudt may, kg/s; V - Van tde ddu bfta; f - He sd trd sdt, f = 0,8 - 0,9 ftng vdi van tde ddu bua - 0 m/s [9] Thay cac gid tri vdo ta cd: Doi vdi may nang sudt 0,8 - 0,9 tdn/h 0,236.85' = 17.051 PT ^"«"~ (1-0,8) Thdng thudng cdng sudt tieu thy cho viec lam lim chuyin khoi nguyen lieu budng nghiin vd chay khdng tdi bdng 15 - 20% cdng sudt Iam nhd nguyen lieu, vdy cdng suat cho may nghien la: N = (1,15-1,2) Nngh Cdng sudt cdn thilt cho mdy nghien Id: N = l,2x 17.051 =20.461 W Chpn ddng ca dien cdng sudt 22 kW, n = 2960 v/ph, dien dp 380 - 660 V 3.2.2 He th6ng hiit va loc tach bot nghiin Tren ca sd phucmg dn bo tri may mdc thilt bi, tinh loan trd luc, ton thdt dp suat dd lua chon dugc quat hftt, dudng kinh dng vd thilt bi Igc tdch bdt phu hgp, cy the: - Dudmg kinh dng d = 150 mm; - Quat hut CF8 - 18 N°5,5; luu lugng Q = 2.000 - 2.500 m^/h, cdt dp P = 650 - 600 mm H2O vd cdng sudt ddng ca dien N = 7,5 kW; - Thilt bi lpc tach bdt dang tfti vdi: 21 tui vdi tdng dien tich tfti lpc Id 12,86 m^ 3.2.3 Lu-a chon sang phan loai Bang Thong sd ky thuat cua miu sang phan loai bpt nghien ciru TT 112 Dac tinh ky thuat Don vj M I U sang nghign cCru Du-cyng kinh sang mm 600 Chieu dai sang mm x 0 = 1.600 Toe quay trge ban chai v/ph 30; 40; 50 So hang ban chai hang Cong suat trge ban chai kW 0,75 Toe dp quay sang v/ph 10; 12,5; 15 Kieh thu-ac 16 \ir&\ sang (im 200; 500; 800 Cong suat quay trdng sang kW 0,75 Dign tich lu'di sSng x , = 3m^ Trong dieu kien Viet Nam dl phdn loai tdt, bdt sau nghiin nen dimg sang dang ludi quay, ben cd ban chdi quay vfta cd tac dung quel, ddy nguyen lieu qua ludi sang, vfta lam sach ludi sang la cd tinh kha thi nhat Tren ca sd khich thudc sang Turbo sifter cua hang Stloz - Phap, da chpn cdc thdng sd cho mau sdng phan loai bdt nghien nghien cftu nhu bang dl thiet ke, che lao 3.3 K§t qua khao nghiem 3.3.L Kit qua thi nghiem co tai cac thiet hi don le Thi nghiem cd lai cua lung may va ca he thdng dugc thuc hien vdi hon hgp nguyen lieu vdi ly le nhu sau: - Ngd hat: 45,5% - Khd dau Inch Iy: 45,5% - San khd dap nhd sa bd: 9,0% r ^ a Kit qua tliingliiem cd tdi mdy nghiin Vdi nguyen lieu Ihi nghiem jieu tren va ludi sang nghiin Id