Hdi nghi Khoa hgc ky nijm 35 nam Viin Khoa hgc vd Cdng nghi Viet Nam - Hd Ndi 10/2010 NGHIEN c t r u THU^C NGHIEM QUA TRINH SAY VAT LIEU DE BIEN TiNH NHIET TREN THIET BI SAY DA NANG SU^ DUNG DIEN TRd, BOM NHIET VA BlTC XA HONG NGOAI Nguyen Thi Thdy Van, Nguyen Phiic Hoang Duy, Pham Thi Thuy Phuong, Duong Huynh Thanh Linh, Nguyin Tri, Hoang Tiln Cudng Vien Cdng nghe hda hgc; Sd Mac Dinh Chi, Quan 1, TP HCM Email: ict38237536@vast-hcm.ac.vn Tom tat: Trong nghiin ciru ndy, md hinh thiit bi sdy ddi luu da ndng dugc thiit ke, chi tgo vd thit nghiem trin mdt sd vdt lieu sdy diin hinh Kit qud thie nghiem chung td thiit bi sdy da ndng cd thi dugc sie dung di khdo sdt dnh hudng cua cdc thdng sd hogt ddng quan nhu van tdc, dm vd nhiet tdc nhdn sdy din hiiu qud cita qud trinh sdy (dugc ddnh gid dua tren thdi gian sdy, ndng lugng tiiu hao cho qud trinh sdy vd chdt lugng sdn phdm sau sdy) Ngodi ra, viec so sdnh hiiu qud cua cdc phuang phdp sdy vd chi sdy khdc ciing di ddng dugc thuc hien tren thiit bi sdy da ndng ndy Cdc yiu td dnh hudng din qud trinh sdy ddi luu sie dung bom nhiet, diin trd vd biec xg hdng ngogi dugc khdo sdt riing le trin cdc logi vdt lieu di biin tinh nhiet Cdc kit qud nghiin cieu cho thdy uu thi vugt trdi vi thdi gian sdy, ndng lugng tiiu hao vd chdt lugng sdn phdm sau sdy cua phuang phdp sdy ddi luu sit dung bom nhiet so voi cdng nghi sdy ddi luu thdng thudng (sie dung diin tra di gia nhiet cho tdc nhdn sdy) vd cdng nghi sdy bdng biec xg hdng ngogi Abstract: A pilot-scale multipurpose convection dryer was designed, manufactured and used to investigate drying process of some materials that are easily denatured by heat The results showed that this specific dryer can be used to study the effect of some main operating parameters, such as velocity, humidity and temperature of air, on drying time, power consumption of drying process and quality of the dried products In addition, comparison of many different drying techniques, involved heat pump drying, traditional convection drying and infrared drying, can be made using this mutipurpose dryer The heat pump drying has been showed its dominant effecst on drying specific materials compared with traditional convection drying as well as infrared drying 417 Tiiu ban: Mdi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7 M DAU Say la mdt nhiing phuong phap da va dang dugc sir dung phd bien de bao quan thuc pham va dugc pham Qua trinh say la qua trinh chuyen pha Idng (chu yeu la nude) tir vat lieu say (VLS) vao tac nhan say (thdng thudng la khdng khi) Ket qua la, sau qua trinh say, ham lugng nude vat lieu dugc giam den miic can thiet nham ban che su phat trien ciia vi sinh vat, nhd dd, vat lieu sau say cd the dugc bao quan mdt thdi gian dai Tuy nhien, hieu qua ciia mdt qua trinh say khdng chi dugc danh gia thdng qua tdc giam am vat lieu ma cdn phai tinh den chat lugng san pham sau say (bao toan mui vi, mau sac, cac chat dinh dudng va vitamin vat lieu) va chi phi nang lugng tieu hao cho qua trinh say dd [1] Tiiy theo ban chat cua vat lieu va yeu cau san pham sau say ma chiing ta lira chgn phuong phap say (PPS) thich hgp, dd say ddi luu nhiet la PPS da dugc sir dung phd bien d nude ta tir rat lau Tuy nhien, ngoai nhimg uu diem nhu qua trinh say don gian, chi phi dau tu thiet bi thap, , PPS ciing tdn tai nhieu nhugc diem nhu thdi gian say dai, san pham sau say de bien tinh nhiet va chi phi nang lugng cao De nang cao hieu qua cho PPS ddi luu co dien, nhieu PPS ddi luu cai tien da va dang dugc nghien cuu thuc nghiem [2, 3], dd, phd bien nhat la PPS ddi luu sir dung biic xa hdng ngoai va bom nhiet Tuy nhien, cac nghien ciiu van chua lam sang td mdi lien quan giira cac thdng sd boat ddng cua timg PPS nhu van tdc, am, nhiet tac nhan say (TNS) den hieu qua qua trinh say Chinh vi vay, cdng trinh nghien ciiu nay, thiet bi say ddi luu da nang sir dung bom nhiet, dien trd va biic xa hdng ngoai da dugc chiing tdi nghien ciiu, thiet ke, che tao va thir nghiem tren VLS de bi bien tinh qua trinh say la ca rdt va tdm sii Anh hudng cua cac thdng sd boat ddng quan trgng nhu van tdc, am va nhiet TNS den hieu qua cua timg qua trinh say cGng dugc khao sat va lam sang td Tir dd, tien hanh so sanh hieu qua cua cac PPS va che say (CDS) khac THU'C NGHIEM 2.1 Dung cu vd thiit bi sit dung: Khao sat qua trinh say cac loai vat lieu d cac ch§ siy va PPS khac tren thiet bi say da nang cd nguyen ly hoat ddng nhu hinh He thdng siy da nang (Viet Nam) cd cac thdng sd ky thuat nhu sau: Kich thudc thiit bi: L 990 x W 450 x H 1.850 mm; Cdng suat bom nhiet: Nmax = 0,5 HP; Luu lugng TNS cd Xh.h dugc diSu chinh d hai miic: cao (161 m3/h) va thip (124 m3/h); Nhiet TNS cd thS dilu chinh tir 45 - 75oC nhd bd dieu khien nhiet do; Van tdc TNS budng say cd thS thay ddi d 03 miic khac nhau; Den hdng ngoai dugc lap tren cac khay siy, chu ky tit/md dugc dilu chinh nhd timer Cac dung cu sir dung gdm: Can phan tich (TE1502S - Satorius); May tdc gid va im khdng (Hygro Thermo -Anemometer, Extech) Cum bom nhiet, den hong ngoai va bd gia nhiet dien trd cd the boat ddng ddc lap hoac kit hgp vdi tiiy theo PPS dugc khao sat 418 Hdi nghi Khoa hgc ky niem 35 ndm Viin Khoa hgc vd Cdng nghi Viet Nam - Hd Ndi 10/2010 9* vm VII VI III M IV Y^-i r Hinh 1: So dd nguyen ly cua thiit bi sdy da ndng (I-Ddn bdc hai; II-Mdy nen; III-Ddn ngung tu; IV-Diin trd; V-Budng sdy; VI-Khay sdy; VII-Den hdng ngogi; Vlll-Cita ra) 2.2 Vat lieu say: Ca rdt va tdm sii 2.3 Tien hdnh thuc nghiem: Cac PPS va che say da khao sat khudn khd bai bao dugc trinh bay d bang Bdng 1; Cdc PPS ddi luu vd thdng sd hogt ddng tuong ieng TT Phuang phdp sdy Ky hiiu Thdng sd cua TNS Nhiet do, "C Van toe, mis Luu lugng m^/h Do dm, %) TNS Biic xa hdng ngoai I - 0,55 60,0 Dien trd II 55 0,55 15,3 Bom nhiet (1) m.i 45 0,55 6,2 Bom nhiet (2) III.2 55 0,55 4,6 • Bom nhiet (3) III.3 55 1,10 4,6 Bom nhiet (4) III.4 55 1,65 4,6 Bom nhiet (5) III.5 55 0,36 4,8 161 124 D I lam sang td anh hudng cac yeu td cua qua trinh say nhu van tdc, am cua TNS ciing nhu danh gia uu nhugc dilm cua timg PPS, chiing tdi xac dinh thdi gian say khd vat lieu, am vat lieu theo thdi gian, danh gia cam quan mau sac cua san pham sau say va nang lugng tieu hao cho qua trinh siy Kit qua thu nghiem dugc trinh bay bang va tren hinh 419 ISBN: 978-604-913-013-7 Tieu ban: Mdi tru&ng vd Ndng lugng Bdng 2: So sdnh hiiu qud cita cdc PPS khdc sdy tdm din dm 19% Chdt lugng sdn phdm Phuong phdp sdy Thai gian sdy, phut Ndng lutyng, kWh Kem I 416 2,65 II III.2 312 250 Chap nhan dugc Tdt 9,09 7,75 Hinh 2a cho thay, de say tdm sii den cimg am, thdi gian say bang PPS ddi luu su dung dien trd ludn cao hon hai PPS cdn lai Tdc say cua PPS ddi luu sir dung bom nhiet giai doan dau qua trinh say cao gap ddi so vdi PPS ddi luu sir dung dien trd va biic xa hdng ngoai (hinh 2.b) Ket qua d bang neu tren cho thay, thdi gian say tdm den am 19% cd the nit ngan den 20%) sir dung PPS cd ket hgp bom nhiet so vdi PPS ddi luu thdng thudng Them vao do, nang lugng tieu hao cho qua trinh say ddi luu cd sir dung bom nhiet chi bang 85% so vdi qua trinh say ddi luu nhiet Dieu la do am ciia TNS trudng hgp sir dung bom nhiet chi bang 0,3 lan so vdi trudng hgp sir dung dien trd gia nhiet thdng thudng Mdt uu diem khac cua bom nhiet la nang lugng tieu tdn cho viec gia nhiet TNS thdng qua viec "van tai nhiet" thap hon so vdi tmdng hgp sir dung dien trd de "cap nhief cho TNS Trong ca ba PPS thi say ddi luu vdi biic xa hdng ngoai la PPS cd thdi gian say dai nhat va chat lugng san pham sau say kem (be mat san pham chai ciing va ddi mau), mac du nang lugng tieu tdn cho qua trinh say chi bang 29%) so vdi qua trinh say ddi luu thdng thudng Dilu cd the giai thich rang chu ky bat/tat den hdng ngoai chgn 60 giay/60 giay la qua cao, hay ndi each khac, thdi gian tat den hdng ngoai de thai am va lam diu be mat VLS qua thip khiln cho be mat vat lieu bi qua nhiet va trd nen chai ciing, dd, am tir ben vat lieu kho thoat ngoai Ket qua la thdi gian say keo dai va chat lugng san pham sau say kem Tuy nhien, vdi uu diem tiet kiem nang lugng, PPS ddi luu sir dung biic xa hdng ngoai vin cd kha nang iing dung cao Van de quan trgng la chgn dugc chu ky bat/tat den hdng ngoai phii hgp vdi timg VLS nham giam thdi gian say va nang cao chat lugng san pham sau siy 100 200 300 400 r)oa aimtuyeat itodi, Uk ('/^ 1)tigian^y,t(iiit) Hinh 2: Dudng cong sdy (a) vd dudng cong tdc sdy (b) tdm su voi PPS khdc 420 Hdi nghi Khoa hgc ky niem 35 ndm Viin Khoa hgc vd Cdng nghi Viet Nam - Hd Ndi 10/2010 3.2 So sanh cac che say khac cua phuong phap say doi luu su dung bom nhiet Cac CDS vdi nhiet do, am va van tdc TNS khac dugc khao sat tren thiet bi say da nang vdi VLS la ca rdt va PPS ddi luu sir dung bom nhiet Dudng cong say va dudng cong tdc dp say ciia 05 CDS khac dugc trinh bay d hinh Hieu qua ciia tirng CDS (danh gia thdng qua thdi gian say, nang lugng tieu hao va chat lugng san phim dugc the hien d bang Bdng 3: So sdnh hiiu qud ciia cdc CDS khdc sdy cd rdt din dm 17% vdi PPS ddi luu sie dung bam nhiet Phuong phdp sdy Thdi gian sdy, phut Ndng lugng, kWh Chdt lugng sdn phdm III.l no 17,79 Tdt III.2 410 13,87 Tdt III.3 218 7,38 Tdt III.4 194 6,56 Tdt III.5 405 13,41 Tdt De danh gia su anh hudng cua nhiet TNS den bieu qua cua qua trinh say ca rot tren thiet bi say da nang, hai che nhiet say da dugc khao sat la 45, va 55°C vdi ciing mdt van tdc TNS la 0,55m/s Ket qua d hinh 4a cho thay tang nhiet say tir 45°C len 55°C, thdi gian say ca rdt den ciing mdt am giam gan 50% Tdc say d nhiet dp 55°C ciing cao gan gap ddi so vdi say d nhiet 45 °C sudt qua trinh say (xem hinh 4b) Chinh vi vay, mac dii nang lugng tieu tdn cho viec nang nhiet TNS tir 45°C len 55°C la kha cao nhung tdng chi phi nang lugng cho toan bg qua trinh say tmdng hgp say d 55°C chi bang 78%) so vdi siy d 45°C (xem bang 3) Them vao do, chat lugng san pham sau say ca hai trudng hgp tuong tu cho nen cd the ket luan rang trudng hgp say ca rdt, nhiet dp say tdi uu cho qua trinh siy ddi luu sir dung bom nhiet la 55°C b) 120 240 360 480 600 720 840 Thoi gian say, t (phut) 500 1000 DO a mtuye tdo i,Uk(^ Hinh 3: Duong cong sdy (a) vd dudng cong tdc sdy (b) cd rdt voi cdc CDS khdc Anh hudng cua van tdc TNS den hieu qua qua trinh say ddi luu sir dung bom nhiet ciing da dugc khao sat va danh gia Hinh a cho thay thdi gian say ca rdt dugc riit ngan tang van tdc TNS Cu thi, vdi van tdc TNS la 0,55 m/s, thdi gian say ca rdt de dat den am 17%) la 421 Tiiu ban: Mdi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7 410 phiit, nhung van tdc TNS tang len 1,10 m/s thi thdi gian siy chi cdn 218 phiit (giam 47%) so vdi tmdng hgp III.2) Tuy nhien, tang van tdc TNS len 1,65 m/s thi thdi gian siy cdn 194 phiit, giam khdng dang ke so vdi tmdng hgp III.3 (11%)) Dilu cd thi giai thich thdng qua dudng cong tdc say d hinh 5b Cd thi thiy, giai doan diu cua qua trinh say, nhi$t dp va am cua TNS ca ba tmdng hgp la bang nen yeu td anh hudng chinh den tdc say la van tdc TNS, dd, giai doan nay, tdc say cua cbl III.4 > III.3 > III.2 Tuy nhien, giai doan say giam tdc thi tdc say cua che III.4 xap xi vdi che III.2 be mat vat lieu liic da khd nen van tdc TNS khdng cdn la ylu td anh hudng chinh niia Chinh vi vay, thdi gian say va nang lugng tieu hao cho qua trinh siy ca rot den am 17% tmdng hgp van tdc TNS la 1,10 m/s va 1,65 m/s la tuong duong Tdm lai, cd the ket luan rang viec tang van tdc TNS se nit ngan thdi gian say va nang lugng tieu hao Tuy nhien, tmdng hgp say ca rdt, van tdc TNS toi uu chi vao khoang 1,1 m/s Nham muc dich tim luu lugng khdng cap tdi uu timg giai doan siy tren he thing say trien khai thuc te, anh hudng luu lugng khdng cip qua ciun tach im cua PPS ddi luu sir dung bom nhiet dugc tien hanh khao sat va danh gia so bd Luu lugng khdng qua cum tach am dugc khao sat d miic 161m^/h va 124m^/h Tuy nhien, hai miic luu lupng xip xi nhau, nen khdng cd sir khac biet rd ve van tdc va am TNS ben budng siy (xem bang 1) Do dd, thdi gian say, tdc say va nang lugng tieu hao cho qua trinh siy d ca hai chi la tuong duong De cd thi hilu rd hon anh hudng cua luu lugng TNS den hieu qua qua trinh say, can tien hanh khao sat d cac miic luu lugng cd khac biet cao hon KET LUAN Tir nhirng ket qua nghien ciiu thuc nghiem d tren, chiing tdi di din kit luan nhu sau: - Thiet bi say da nang da thiet ke, che tao cd the dugc sir dung dh khao sat anh hudng cua cac thdng so boat ddng quan trgng nhu van tdc, im va nhiet TNS din hieu qua cua timg PPS ddi luu don le (su dung dien trd, biic xa hdng ngoai va bom nhiet) hoac kit hgp - Tir nhiing so sanh vl hi?u qua cua cac PPS va CDS (nhiet do, van tdc, im cua TNS) dugc thuc hien tren thiit bi say da nang nay, PPS ddi luu sir dung bom nhiet da cho thiy uu dilm vugt trdi vl viec giam dang kl chi phi van hanh, nit ngin thdi gian siy va dam bao chit lugng san phim Chinh vi vay^ PPS hien dang din thay thi PPS ddi luu cd diin tmdng hgp say cac san pham dl bien tinh Imh vuc thuc phim, dugc phim TAI LIEU THAM KHAO Nguyen Van Lua, "Ky thudt sdy vdt lieu ", Qua trinh thiit bi cdng nghe hoa hpc tap 7, Tmdng Dai hgc Bach khoa TP.HCM (1994) Hoang Nggc Ddng va Le Minh Tri, "Nghiin citu xdy dung md hinh thuc nghiem thiit bi sdy bdng bam nhiet" Tap chi Khoa hgc va Cdng nghe, DH Da Ning, sd (27), 2008, tr 8-13 Nguyen Thi Thiiy Van, Nguyen Tri va nnk, "Ifng dung cdng nghi sdy ddi luu kit hgp tdch dm - bam nhiet di sdy ndm linh chi", TC Khoa hgc va Cdng nghe, Sd 47 (3 A) 2009, tr 218-225 422 NHA XUAT BAN KHOA HOC TlT NHIEN VA CONG NGHE 18 dudng Hoang Quoc Viet, Ciu Giay, Ha Noi DT: Quan ly Tong hop: 04.22149041; Phdng Phat hanh: 04.22149040; Bien tap: 04.22149034; Fax: 04.37910147, Email: nxb@vap.ac.vn; vyww.vap.ac.vn HOI NGHI KHOA HOC • • • KY NIEM 35 NAM T H A N H LAP VIEN KHOA HOC VA CONG NGHE VIET NAM • • • • 1975 - 2010 TIEU BAN: MOI TRUONG VA NANG LUONG Chju trach nhiem xuat ban Giam doc TRAN VAN SAC Tong bien tap GS.TSKH NGUYEN KHOA SON Bien tap: Phong bi§n tap Ky thuat vi tinh: Hong Ngan Trinh bay bia: Hong Ngan In 200 cuon kho 20 x 29cm tai: Nha In Khoa hoc va Cong ngh$ Giay xac nhan dang ky so: 2673/CXB-QLXB 15/9/2010 cua Cue Xuat ban So xac nhan dang ky KHXB: 927-2010/CXB/005 - 05/KHTNCN In xong va nop lu'u chieu thang 10 nam 2010