Bi 1: Xc nh nht ca cht lng, trng thi khng kh m, h s phn bI- XC NH NHT CA CHT LNG1) L thuyt Khi cht lng chuyn ng s to ra qu trnh trt gia cc lp cht lng ging nh hin tng ma st, v c lc ma st trong lng lp cht lng. Lc ma st gy ra sc cn ca cht lng i vi chuyn ng tng i ca cc phn t cht lng. Tnh cht ny ca cht lng thc gi l nht.

Ni ma st:

Gi s lp A chuyn ng vi vn tc w, lp B chuyn ng vi vn tc w+dw, hai lp chuyn ng song song v khong cch hai lp l dn.Khi : S = .F., NS lc ma st bn trong cht lng, NF-din tch mt tip xc gia cc lp cht lng, m2 gradient vn tc- h s t l ph thuc vo tnh cht ca cht lng, gi l nht ng lc hc. = , N.s/m2Ngoi ra th nguyn ca nht ng lc hc cn tnh theo cc i lng sau kg/m.s, Poa (P), centipoa (cP).1P =100cP =0,1 N.s/m2 =0,0102 kp.s/m2Nu lp t s ca nht ng lc hc v khi lng ring ca cht lng gi l h s nht ng hc hay nht ng hc, k hiu = , m2/sn v o nht ng hc l stc (St).1 St =1 cm2/s = 100 cSt (centistc)C nhiu phng php o nht, sau y s gii thiu phng php o nht bng nht k mao qun. ng vi mi cht lng c nht khc nhau phi c mt nht k c gii hn o ph hp.2) Tin hnh th nghim v ly s liu Phng php ny theo tiu chun ASTM D 445 nhm xc nh nht ng hc ca nhng sn phm du m trong cng nh c, bng cch o thi gian mt th tch cht lng xc nh chy qua mt mao qun thy tinh di tc dng ca trng lc. nht ng hc l kt qu tnh c t tch s gia thi gian chy v hng s nht k.

-Nht k mao qun -B iu nhit-Nhit k chnh xc-ng h bm giy

-Gi nhit b iu nhit n nh theo yu cu nhit th nghim.-Nht k phi ra sch, kh v cc thang o ph hp vi cht lng cn xc nh nht, loi c mao qun rng dung cho cht lng nht ln v ngc li. Nht k thch hp phi c thi gian chy >= 200 giy.-Np cht lng vo nht k vi th thch thch hp (ty theo tng loi nht k).-Nht k np phi gi trong b iu nhit khong 30 pht m bo nhit cht lng cn tin hnh o, chnh li cht lng trong nht k nu cn thit. Nu o nht ti nhit phng th khng cn a vo b iu nhit.-Dng bp cao su to lc ht hay y cho mc cht lng trong mao qun ln cao hn mc dnh du th nht khong 5 mm. cht lng chy t do v dung ng h bm giy xc nh thi gian cht lng chy t mc nh du th nht n mc nh du th 2.-Lp li th nghim sao cho kt qu sai s gia hai ln khng qu 0,2 %.-Thng tin hnh 3 ln o thi gian v ly gi tr trung bnh.t = (s)-Xc nh nht ca mu ti nhit phng, 400C, 1000C.-i vi nht k loi 1: = C.t (cSt)C- l hng s nht k, cSt/s-i vi nht k loi 2: on trn: 1= C1.t1, cSton di: 2= C2.t2, cSt = C1, C2 hng s nht k on trn v di, cP/s T nht ng hc 400C v 1000C tnh ra ch s nht theo cng thc Pavlp:K= = constTrong : T1, T2 Nhit m ti cht lng A c nht 1, 2- Nhit ca cht lng tiu chun bt k c cng nht 1, 2 Nh vy tnh nht ca cht lng A ti nhit T3, ta ch cn xc nh nht ca cht lng tiu chun nhit 3.K= 3 = + 2Ti liu tham kho:1) Cc qu trnh thit b trong cng ngh ha cht v thc phm; tp 1: cc qu trnh thy lc, bm, qut, my nn; nh xut bn khoa hc v k thut 2002; tc gi Nguyn Bin.2) Thy lc i cng, GS.TSKH Trn Vn c, Nh xut bn gio dc 2004.

II- XC NH TRNG THI CA KHNG KH M

1. Mc chBi th nghim gip sinh vin bit cch xc nh trng thi khng kh m thng qua vic o nhit bu kh v bu t ca khng kh.2. nghay l bi th nghim c ng dng quan trng trong thc t.

Khi tnh ton qu trnh sy cn bit nhit im sng v l gii hn ca qu trnh lm lnh hn hp khng kh m trong iu kin .Bit c nhit im sng chn nhit cui ca qu trnh sy phi ln hn nhit im sng trnh ngng t trn b mt vt liu sy.Trong d bo thi tit ngi ta dng phng php ny xc nh trng thi ca khng kh m ti im o vo thi im o.3. L thuyt ca phng php o c dng th I-x ( th L.K Ramzin)

Trng thi ca khng kh m c c trng bng 4 thng s trng thi c bn l t0C, I, x, . Nu dng th I-x ta ch cn 2 trong 4 thng s c bn trng thi ca khng kh m, v mi im trong th I-x l giao im ca 4 ng: ng nhit (to), ng m tng i (), ng hm m (x) v ng enthalpi (I).a. im sng (ts)

C mt hn hp khng kh m cha bo ha hi nc. Lm lnh hn hp ny trong iu kin th nhit ca khi kh gim dn, m tng i ca khng kh tng dn n trang thi bo ha hi nc ngha l . Nu tip tc gim nhit ca kh th hi nc trong khi khng kh s bt u ngng t, hm m ca hn hp kh bt u gim. Nhit ca khng kh tng ng vi trng thi bo ha hi nc gi l nhit im sng, k hiu l ts. Vy im sng l gii hn ca qu trnh lm lnh khng kh trong iu kin hm m .b. Nhit bu t (tu)Nu ta cho bay hi nc c trong khi khng kh cha bo ha trong iu kin on nhit, ngha l qu trnh bay hi nc din ra do nhit ca khi khng kh cung cp m khng cn cung cp thm nhit v cng khng cn ly bt nhit ca khi khng kh . Khi nhit khng khi s gim dn, hi m tng dn n khi khi khng kh bo ha hi nc th h t c trng thi cn bng ng. Ngha l c trn mt n v b mt bc hi, trong cng mt n v thi gian. Lng m bay hi vo trong khng kh bng lng m ngng t t khng kh vo nc. Nhit ny gi l nhit bu t, k hiu l (tu)Vy nhit bu t l mt thng s c trng cho kh nng cp nhit ca khng kh lm bay hi nc cho n khi khng kh bo hoa hi nc.c. Nhit bu kh (t)Nhit bu kh gi l gi tr c c trn nhit k thng, k hiu l (t)

Hiu s gi l th sy c trng cho kh nng ht m ca khng kh4. Phng php o nhit bu t.

o nhit bu t ta dng m k. Ta cng c th dng nhit k thng c bc vi t. Mt u vi t c nhng vo trong nc, to ra mi trng khng kh xung quanh bu thy ngn c .Gi tr c trn nhit k bu t l nhit bu t (tu). Gi tr c trn nhit k thng l nhit bu kh (t).

5. Dng c v thit b th nghim

1. Nhit k thy ngn 0100oc (2 chic)2. Cc thy tinh 50ml.3. Gin Ramzin

6. Tin hnh th nghim v xc nh cc thng s Lp rp dng c th nghim nh hnh 2. o nhit bu t. tu (oc) o nhit bu kh. t (oc) Xc nh nhit im sng ts (oc) a ra cc i lng c c vo gin RamJin theo th t cc bc sau:Bc 1: Vch ng ng nhit qua im tng ng vi t.

Bc 2: Vch ng ng nhit qua im tng ng vi tu gp ng (3)

Bc 3: Vch ng thng qua (3), ct ng thng ng nhit qua t ti A

Bc 4: T A vch ng ti khi ct ng ti im (5).Bc 5: Vch ng ng nhit qua (5) ta c nhit im sng ca khng kh trng thi tng ng im A.

Bc 6: Cng theo ng ta xc nh c hm m ca khng khx (im 8)Bc 7: Xc nh p sut hi ring phn ca hi nc trong khng kh (im 9)

i chiu vi gi tr xc nh bng gin RamJin ta c th xc nh p sut ring phn ca hi nc trong khng kh theo cng thc sau:

Bc 8: Qua im A ta xc nh m tng i ca khng kh trng thi A.7. Kt lunTrng thi ca khng kh m ta kho st c c trng bng cc thng s sau:

Ngy.gi..a im kho st.....

tI

tu

ts

tnh cho gi tr ng hn.-Dng m k c kt qu m trn mt ng h v so snh vi gi tr xc nh c theo phng php trn. a ra nhn xt.

Ti liu tham kho

[1] Nguyn Bin Cc qu trnh, thit b trong cng ngh ha cht v thc phm, tp 4, NXB: KH & KT, H Ni, 2008.

[2] Trnh Vn Dng QT v TB cng ngh ha hc v thc phm. Bi tp truyn khiNXB: H Quc gia TP.HCM, 2008.

II- XC NH H S PHN B1- Mc ch : Gip cho sinh vin hiu v s chuyn dich ca cu t phn b trong hai pha cn bng vi nhau v cch xc nh h s phn b . l mt i lng c trng cho qu trnh chuyn khi, c bit i vi qu trnh trch ly lng-lng.

2- L thuyt cn bng pha Ta kho st s chuyn cht ca amoniac lm v d.Amoniac l mt cu t phn b c trong hn hp ca n vi khng kh. Hn hp b hp th bng nc sch. Khi cha c s cn bng amoniac s chuyn ti pha hi y, nng ca n bng y, sang pha lng x c nng u ca amoniac bng khng, ngha l x = 0. Khi amoniac ha tan vo nc th cng bt u s chuyn mt phn phn t amoniac theo hng ngc li vi tc t l thun vi nng amoniac v ti bin gii pha .Theo thi gian tc chuyn dch amoniac vo nc gim dn v tc chuyn dch ngc li tng dn .S chuyn dch ny din ra cho n khi no tc chuyn dich v hai pha bng nhau. Khi s thit lp mt cn bng ng s chuyn dch vt cht t pha ny n pha khc s din ra khng r rt lm. thi im cn bng, gia nng cn bng hay nng gii han ca cu t trong cc pha c mt mi quan h xc nh (ty thuc nhit v p sut) nh sau:

( 1 )

( 2 )

: nng NH3 trong pha lng

*: nng NH3 trong pha hi cn bng vi n T s nng cc pha trng thi cn bng vi n l h s phn b

m = H s phn b l tan ca gc nghing ca ng cn bng, i vi ng cong cn bng th m khng phi l mt hng s, n c th ln hn, nh hn hay bng 1.Vi qu trnh trch ly , m cng ln hn 1 th cng d trch ly .3. Dng c v ha cht : - Cc thy tinh 50ml- Cc thy tinh 200ml- My khuy t- Buret 25ml- Toluen ( sch )- Axit xalycilic ( tinh th)- Nc ct- Dung dch NaOH 1N- Phenolphtalein- ng ng 100ml - Phu chit 200ml4. Phng php thc nghim : Cho vo cc thy tinh 50ml nc ct v 50ml toluene sch . Cn a gam (khong 0,5 gam) axit xalycilic tinh th ri cho vo cc c hn hp nc v toluene trn. Khuy lin tc trong 15 pht. Sau , ton b dung dch vo phu chit, ch hn hp phn lp r rt (khong 30pht), thn trng m van ly ra phn nc trng pha di, em i chun Ly ra 10ml vo 1 cc ri chun bng NaOH 1N c cht ch th phenolphthalein (lm 3 ln th nghim).

Da vo cng thc : V1N1= V2N2Trong : + V1_ml dung dch axit xalycilic + N1_nng ca dung dch + V2_ml dung dch NaOH 1N + N2_Nng dung dch NaOH 1NVy nng cu dung dch axit xalycilic l :

N1= Tnh lng axt xalycilic tan vo trong 50ml nc l : m1 V lng axt phn b trong toluene l : m2 = a m1T y ta xc nh h s phn b :

m = 5. Ti liu tham kho :[1] Nguyn Bin . Cc QTTB trong cng ngh ha cht v thc phm tp 4 NXB KHKT, 2006, H Ni , chng 4 . Trch ly cht lng ( tr 197 ) .

Bi 2: Th nghim reynold, dng chy qua lI: TH NGHIM REYNOLDS1) Mc ch C 2 trng thi chuyn ng ca lu cht: Trng thi chy tng v chy ri, gia hai trng thi ny c trng thi chy qu . Cc trng thi ny c nhng tnh cht khc hn nhau v to ra nhng nguyn tc khc nhau gy ra s tiu hao nng lng ca dng chy.M hnh th nghim ny gip sinh vin hnh dung c: Quan st, phn bit hai trng thi ca lu cht v s qu t trng thi ny sang trng thi kia ca lu cht. Xc nh gi tr ca Re dng chy tng, chy ri v so snh vi kt qu thc nghim ca Reynolds.2) L thuyt -Cc phn t chuyn ng song song nhau theo mt ng thng vi vn tc chm gi l chy dng. Ngc li cc phn t chuyn ng vi vn tc nhanh theo ng thng khng th t vi cc hng khc nhau to thnh mt dng ri gi l chy ri (chy xoy).

Khi vn tc tng ln dng b chy ri, nn xut hin dng xoy, cc phn t chuyn ng vi vn thay i c gi tr v hng to thnh parabol t. Dc thnh ng c lp bin, lp bin vn tc cht lng gim dn v st thnh ng bng 0. Trong lp bin cht lng chy tng.- quan st ch chuyn ng ca dng chy cho mt dng cht mu chuyn ng cng dng chy trong ng. Khi lu lng nh tia mu chuyn ng theo ng thng, khng dao ng v dung dch mu khng c s ha trn vo nc. Khi lu lng tng n mt mc no th tia mu bt u gn sng, kt thc giai on chy tng.-Nu lu lng dng chy tng n mt gii hn nht nh th tia mu b dao ng mnh v t on, ha trn vo dng chy. Lc ny chuyn sang chy ri hon ton. Theo Reynolds dng chy chuyn t trng thi chy tng sang chy ri phi qua bc trung gian l trng thi chy qu .-Khi dng chy trng thi chy ri hon ton v tin hnh gim lu lng n mt mc no tia mu tr v trng thi gn sng v chy theo ng thng l dng chy trong ng chuyn t trng thi chy ri sang chy tng.-S thay i trng thi lu cht ph thuc vo mt i lng khng th nguyn Re, c trng cho dng chy c ma sat, c lp theo t s gia lc ma st v lc qun tnh. Re = = Trong : - khi lng ring, kg/m3 w- vn tc, m/s l -chiu di c chng (ng knh), m - nht ng lc hc, Ns/m2 - nht ng hc, m2/s = -Vic tng dn lu lng l tng dn Re, khi Re cng nh th lc ma st nht cng ln v vy mi kch ng ca dng chy s b lc ma sat nht dp tt, ta c trng thi chy tng. Ngc li khi Re ln lc qu tnh tng nn lc ma sat nht khng ln dp tt cc kch ng dn n dng lu cht chuyn sang chy ri.i vi ng v mng dn khng phi l trn ng knh tng ng tnh theo cng thc dt = d = 4 rtl .rtl = Trong : rtl -bn knh thy lc, m f - tit din ng, m2 U - chu vi thm t ca ng, mi vi ng hnh ch nht dng a.b rtl = =dtd = 4 rtl =

3) Tin hnh th nghim v ly s liua) Th nghim Reynolds i vi ng thng- Lu lng tng dn: M kha cho lu lng nc tng dn n khi dng chy n nh, dng ng ong 1 lit o lu lng ca dng chy. o thi gian nc chy y ng hoc mt th tch chn trc, tin hnh 3 ln o vi cng mt mc lu lng dng chy. lu lng dng chy n nh th mc nc trn b phi khng c s thay i. Tin hnh o ng vi 3 trng thi chy tng, qu , ri v lp bng tnh ton.Chy tng: Th tch cht lng (nc) V=m3Thi gian o ln 1, t1 =..(s)Thi gian o ln 2, t2 =..(s)Thi gian o ln 3, t3 =..(s)Thi gian trung bnh, ttb = (s)Lu lng dng chy Q = (m3/s)Vn tc cht lng w = (m/s), S l tit din ng S = (m2)Re = Chy qu :Th tch cht lng (nc) V=m3Thi gian o ln 1, t1 =..(s)Thi gian o ln 2, t2 =..(s)Thi gian o ln 3, t3 =..(s)Thi gian trung bnh, ttb = (s)Lu lng dng chy Q = (m3/s)Vn tc cht lng w = (m/s), S l tit din ng S = (m2)Re = Chy ri:Th tch cht lng (nc) V=m3Thi gian o ln 1, t1 =..(s)Thi gian o ln 2, t2 =..(s)Thi gian o ln 3, t3 =..(s)Thi gian trung bnh, ttb = (s)Lu lng dng chy Q = (m3/s)Vn tc cht lng w = (m/s), S l tit din ng S = (m2)Re = -Lu lng gim dn: Gim dn lu lng v quan st trng thi dng chy xc nh chun s Re ti ba trng thi:Chy ri.Chy qu .Chy tng.a ra nhn xt v gi tr Re o c trong thc nghim vi gi tr ca Reynolds a ra, gii thch s khc nhau .b) Dng chy trong ng ng b gp khcM kha v iu chnh lu lng sao cho trc on ng gp khc l trng thi chy tng. Quan st v nhn xt v trng thi dng chy trong khong sau on gp khc.c) Dng chy trong ng c ng knh khc nhauiu chnh lu lng nc sao cho trong on u tin nc chy tng sau quan st trng thi dng chy ng c ng knh b hn v a ra nhn xt.

Ti liu tham kho: Cc qu trnh thit b trong cng ngh ha cht v thc phm; tp 1: cc qu trnh thy lc, bm, qut, my nn; nh xut bn khoa hc v k thut 2002; tc gi Nguyn Bin.

II: DNG CHY QUA L1) M t: Xc nh lng cht lng chy trong mt thi gian nht nh2) ng dng: Tnh ng knh l cung cp nhin liu lng Tnh ng knh l trong xe vn chuyn xng du Tnh ng knh ng dn nc ca xe ti cy trong cng vin Tnh ng knh ca l phun xng trong b ch ha kh trong ng c t trong Dng trong b phn gim chn bng thy lc ca xe gn my Tnh chiu xa dng nc trong cu ha Thit k trang tr nhc nc.3) Tin hnh th nghim v ly s liua) S chy qua l khi mc cht lng n nh. Bm nc vo h thng, xc nh chiu cao ca ct nc mc n nh (H). Xc nh ng knh l dng nc chy qua (D). Dng ng ong v ng h bm dy xc nh th tch nc (V) chy qua l trong thi gian (T). Tin hnh 3 ln v ly gi tr trung bnh.STTV (m3)T (s)

1

2

3

Trung bnh

Xc nh lu lng dng chy: Q = (m3/s) Din tch l: S = . (m2) Vn tc dng chy qua l theo thc nghim: w = (m/s) Vn tc dng chy theo l thuyt: Phng trnh Bernoulli:H + + = +

Do mc nc n nh nn w2 = 0, p1 = p2H = w1 = (m/s)So snh kt qu w v w1 v gii thch s khc nhau .b) S chy qua l khi mc cht lng thay i. Xc nh thi gian mc cht lng chy t mc H n H1 dng ng bm giy theo di mc cht lng v tin hnh trong 3 ln, sau ly gi tr thi gian trung bnh = (s) Theo l thuyt vi phn biu din qu trnh chy:-S0dH = S.wdT dT = w = S, S0 l din tch l v mt thong cht lng (m2)Thi gian cn thit cht lng chy ht cao HT = -. = Thi gian cht lng chy t H n H1l:T = - (s). So snh kt qu theo cng thc ny v tnh theo thc nghim. Gii thch s khc nhau .c) Tnh chiu xa ca dng nc Vn tc dng nc trc khi ra khi l W0 , b qua sc cn khng kh. Qung ng theo phng ox l x = w0.T

Qung ng dng nc theo phng oy y = Vy dng nc vch ra parabol c dng: y = Vy chiu xa ca dng nc tnh theo chiu cao y: x = Ly mt cao nht nh (y). Sau o vn tc dng nc w0 v chiu xa x, so snh kt qu thc nghim v l thuyt.

Ti liu tham kho: Cc qu trnh thit b trong cng ngh ha cht v thc phm; tp 1: cc qu trnh thy lc, bm, qut, my nn; nh xut bn khoa hc v k thut 2002; tc gi Nguyn Bin.

Bi 3: CHNG CT C HI NC1. Mc ch :Bi th nghim ny gip sinh vin hiu v nguyn l chng h cht lng khng ha tan vo nhau .2. L thuyt qu trnh chng bng hi nc trc tip. p dng nh lut Raoult cho hai cht lng khng tan ln vo nhau: Pt = + p sut hi bo ho ca cu t A v B ti nhit cn kho st (Tra cu s tay qu trnh thit b).Khi hn hp si p sut kh quyn th : + = 1atm = 760 mm HgVy khi chng ct li cun theo hi nc ca hai cht lng khng tan ln vo nhau th gim c nhit si, y chnh l ng dng quan trng trong thc t tch mt s hp cht hu c c nhit si thp, trnh ph hu cu trc phn t cng nh cc phn ng ph xy ra nhit cao. = = , Gi s A l H2O, B l cht cn li cun theo hi nc.Vy khi lng nc thot ra cng vi 1 mol cht lng khng ho tan l:mH2O = 18. (g)Trong thc t khng c nhng cht lng khng ha tan vo nhau . Chng ha tan rt t vo nhau n mc ta coi nh khng tan ln trong nhau .V d: Nh h benzen, nc, cacbon sunphua. Cc hn hp ny c th tch thnh cc cu t ring bit bng phng php lng gn .3. Dng c v ha cht :- Toluen hoc benzen sch- Bnh cu 3 c (nhm) 1 lt 2 chic - ng sinh hn 1 chic- Nhng b - cm trn bnh cu 1 chic- Nhit k 1500C 1 chic - ng thy tinh - ng nha hoc cao su- Bp un bnh cu - ng ong - Phu chit - Cc 50ml

Hnh 1: S th nghim. H thng th nghim c lp rp nh hnh 1, hi nc c to ra bnh 1 theo ng dn 2 sc vo bnh 3 c cha hn hp nc v 50ml toluene n th tch bnh cu Hn hp c gia nhit nh c hi nc sc vo. Trong qu trnh tip xc gia hi v lp cht lng, toluene l cu t cn chng s vo trong hi to thnh mt hn hp bay ln ri qua ng sinh hn ngng t li. Nc ngng t li trong cc em i phn lp, ta o th tch toluene thu c (V:ml). Ri tnh t l thu hi toluene: Qu trnh chng ct kt thc khi thy th tch lp toluene trong cc khng i.Trong qu trnh chng ct ta c nhit ghi nhn trn nhit k. N l mt i lng thp hn 1000C. Khi nhit hi tng cao chng t toluene bay hi ht.

5. Bo co kt qu th nghim : 1-Lng toluen hn hp vi nc 2-Tnh cht vt l ca toluene3-Nhit hi chng4-s ml toluene thu hi c 5-Hiu sut thu hi toluene6- So snh kt qu thc nghim v kt qu c tnh theo l thuyt, a ra nhn xt.7- So snh nhit si ca hn hp nhit k c c v nhit si tra cu c t s tay. Ti sao khi Toluen bay hi ht th nhit trong bnh tng ln v nhit s tng n bao nhiu oC th nc trong bnh bt u si tip.7-Kt lun (Ti liu tham kho: Nguyn Bin, trang 61)

Bi 4: THI NGHIM TRICH LY RN LONG1. Muc ich:- Thi nghim nay giup sinh vin lam quan vi mt trong cac phng phap phn ring mt hn hp cht bng cach dung mt dung mi co tnh hoa tan chon loc i vi mt hoc vai cu t cn thit tach khoi hn hp chung.- Phng phap nay c dung rng rai trong cng nghip hoa hoc, hoa du, thc phm, x li nc thaimt khi khng th dung phng phap chng ct do khng co kha nng v ky thut (vi tao hn hp ng phi, vi san phm khng bn vi nhit) hoc khng co li (vi tiu hao nhiu nhit).- Yu cu c ban cua dung mi: + co tinh hoa tan chon loc;+ mt khac bit ln so vi mt cua dung mi du;+ re tin, d kim nh: nc, dung mi hu c;2. C s ly thuyt- Trong qua trinh trich ly se din ra s chuyn dich cu t t pha nay sang pha khac cho n khi nng cua chung cn bng.- i vi hai cht long khng tan ln nhau la A va C thi s phn b cua cu t th ba B tun theo inh lut phn b: y* = k.x trong o: y*: nng cn bng cua cu t B trong dung mi C. x: nng cua cht B trong dung mi A k: h s phn b phu thuc vao nhit , nng cht bi hoa tan.Vi dung dich loang, k co th coi la hng s va ng cn bng trong thi y = kx coi la ng thng i qua gc toa va co goc nghing bng k.- Co hai loai trich ly ph bin la: + Long long+ Rn - long (la loai ma ta se lam thi nghim nay)Trong qua trinh trich ly rn long dung mi se hoa tan chon loc mt s cu t t cht rn. Bt ky qua trinh trich ly rn long nao cung bao gm cac giai oan sau:+ dung mi thm nhp vao cac mao quan cua cht rn+ hoa tan hoc phan ng hoa hoc vi cac cu t cn tach+ cht hoa tan va dung mi se khuch tan t vt rn vao dung dich.- Qua trinh trich ly rn long tin hanh n khi thit lp c cn bng gia nng cu t phn b trn b mt vt rn (Cgh) vi nng trung binh cua no trong dung dich (C0).- Thng thi gn b mt vt rn s cn bng nhanh chng c thit lp nn Cgh co th ly bng nng bao hoa Cbh. Hiu s Cbh C0 chinh la ng lc cua qua trinh trich ly.- Vn tc trich ly rn long c tinh nh sau:

Trong o : bin thin khi lng vt rn theo thi gian : h s cp khi t pha rn vao pha long F: b mt hoa tan cua vt rn.S thay i nng cht tan trong dung dich c biu din trn hinh 2:

hinh 2: s thay i nng cu t phn b trong dung dch- gn b mt nng cu t phn b t n gia tri Cbh. Cang xa b mt thi nng o giam dn n mt khoang thi con bng C0 la gia tri cua no trong dung dich. : goi la b day gii han lp khuch tan. B day cang nho thi h s khuch tan cang cao.Khuy trn dung dich se lam cho b day cang giam, kha nng hoa tan cht rn cang tng.- Thm na, nhit cang tng thi hoa tan cng cao. Vi Cbh tng theo nhit , nht cua dung dich giam va do o khuch tan cang tng.- Khac vi qua trinh hoa tan thng thng, qua trinh trich ly rn long din ra trong cac mao quan. Nn b mt tip xuc pha cang chuyn su vao bn trong vt rn cang lam giam vn tc cua qua trinh trich ly.Bi vy, vi vt rn tng vn tc trich ly cn nghin nho kich thc vt rn vi no se lam tng din tch tip xc v lm giam di mao qun to iu kin khuch tan thun li hn.3. Thc nghim - Thi nghim trich ly co th tin hanh trong pha long nong (Soxhlet) hoc trong pha hi nong cua dung mi (Grefe).- Trong thi nghim nay ta thc hin trong pha long nong (Soxhlet).Nhng dung cu hoa cht cn thit.+ Si chi khu (dng buc mu)+ Che rn (ban ngoai ch)+ B chng ct (Soxhlet).+ Cn phn tich+ Tu sy- S b tri thi nghim nh hinh ve:

3.1> Chun bi muLm kh nguyn liu bng cch sy nguyn liu 100 -105oC n khi lng khng i l c, ngui trong bnh ht m. Ct mt mnh giy lc kch thc 8 x 10 cm, gp thnh bao nh, sy nhit 105oC, n khi lng khng i, ngui trong bnh ht m, cn bao giy, cn si ch. Ghi nhn si ch v bao giy sy kh hon ton.Cn chnh xc trn cn phn tch mt mu ch khong 2 gam cho vo ti giy trn v dng ch buc li.3.2 Chun b mu trong thit b Soxhlet: t bnh un ln bp un bnh cu, trong bnh cu cha mt lng bnh.Lp bnh chit khp vi ming bnh un. t bao mu vo y bnh chit.Lp ng sinh hn vo bnh chit.t phu thu tinh ln ming ng sinh hn. Lp h thng nc lm mt cho ng sinh hn.Cho nc chy vo, kim tra hot ng ca ng sinh hn.3.3 Tin hnh chit:- Sau khi lp h thng bt ngun in v un si tin hnh chit lin tc. Quan st mu nc chy ra t bnh chit xung bnh un. Khi qa trnh trch ly xy ra th cht cn chit s tan vo nc. Nc c mu nu chy xung bnh cu. Theo di gian trch ly, mu ca nc s nht dn cho n trong khi kt thc qu trnh trch ly.- Sau khi trch ly kt thc ly giy lc cha mu, sy n khi lng khng i nhit 100 105 0C.- Ly mu ra cho vo bnh ht m ngui v tin hnh cn.*. Tnh ton nh sau: + lng mu trc trch ly: m1+ lng mu sau trch ly: m2+ lng cu t cn tch : G = m1 m2+ t l cu t cn tch: G2 = (G1/m1).100 (%)4. Kt lun 5. Ti liu tham kho[1]: Nguyn Bin : tp 4 (trang 218-222)

BI 5: CHNG LUYN I. M UChng luyn l qu trnh tch hn hp lng nhiu cu t thnh tng cu t ring bit da trn c s bay hi khc nhau ca cc cu t trong hn hp.Qu trnh chng luyn c tin hnh trong cc thit b loi thp a v thp m. Khi lm vic, hi i t di ln tip xc vi cht lng chy t trn xung, v hi ngng t li cu t kh bay hi, nhit to ra do qu trnh ngng t ny s lm bay hi mt lng cu t d bay hi. V vy khi lp li nhiu ln bc hi v ngng t nh th, trong dng hi s giu cu t d bay hi, cn trong dng lng s giu cu t kh bay hi. Ni mt cch khc, vi chiu cao thp thch hp (s a tng ng), cui cng trn nh thp ta thu c sn phm c nng cu t d bay hi cao v y thp ta thu c sn phm giu cu t kh bay hi, nng cu t thay i theo chiu cao ca thp v do nhit si cng thay i theo chiu cao ca thp, tng ng vi s thay i nng .II. PHNG PHP TNH TON1. Tnh cn bng vt liu ca thp:H phng trnh cn bng vt liuF = W + P

F.x = W.x+ P.xTrong : F : Lng hn hp u cho vo thp , Kg/sW : Lng sn phm y,Kg/sP : Lng sn phm nh, Kg/s

x, x, x: Nng phn khi lng ca cu t d bay hi trong hn hp u, y v nh thp.2. Cn bng nhit lng ca thp :Chp nhn nhit mt mt do mi trng xung quanh bng 5% lng nhit a vo y thp.Vy lng nhit cn thit a vo y thp l :

Q = (R+1).P.i + W.C.t- F.C.t -G.C.t + 0.05 Q

Hay Q= , W y. - i : hm nhit ca hi , j/kg

- (R+1).P.i : lng nhit do hi mang ra nh thp , W

- W.C.t: lng nhit do sn phm y mang ra , W

- F.C.t: lng nhit do hn hp u mang vo , W

- G.C.t: lng nhit do hi lu mang vo , W

- R: ch s hi lu

- C, C, C: nhit dung ring ca dung dch a tip liu, y v nh thp, J/Kg..Nhit dung ring ca dung dch tnh theo cng thc:

C = ac + ac

a, a : phn trm khi lng ca cu t 1 v 2, J/Kg..

c, c : nhit dung ring ca cu t 1 v 2

t, t, t : nhit ca hn hp u vo thp, ca sn phm y v nh, C.III. XC NH S BC THAY I NNG V CHIU CAO TNG NG VI MT BC THAY I NNG :1. Xc nh s a l thuyt :- Tm ch s hi lu

, : Th tch lng lng hi lu, v lng sn phm nh. m/s. ( y ta chp nhn nhit ca sn phm nh bng nhit hi lu)- V ng cong cn bng theo s liu cn bng lng-hi.- V ng nng lm vic ca on luyn v on chng nh l thuyt hc (ch i nng t phn khi lng hay phn th tch ra phn mol).Ta c phng trnh ng nng lm vic ca on luyn

y = + Phng trnh ng nng lm vic ca on chng:

y = - y :

L= : Lng hn hp u tnh theo mt n v ca sn phm nh.

- Xc nh s a l thuyt xut pht t x( hay x), cc ng nm ngang v thng ng gia ng cn bng v ng lm vic; m s tam gic thu c th chnh l s a l thuyt N. 2. Xc inh chiu cao tng ng ca mt bc thay i nng :Chiu cao tng ng ca mt bc thay i nng xc nh theo cng thc :

h = . y

h - Chiu cao tng ng ca mt bc thay i nng H - Chiu cao ca m, m .

- S a l thuyt.3. H thng chng luyn lin tc loi thp a l c ng chy chuyn vi nhng c tnh k thut sau: ng knh thp D = 90 mm

Chiu cao thp on luynH = 400mm

Chiu cao thp on chng H= 600mm

S a ca thp on luyn N = 2

S a ca thp on chng N = 3un nng nguyn liu u bng in tr, cn un si y thp bng in tr. H thng th nghim ny cho php ta quan st c ch lm vic mi a ca thp .4. Bng s liu cn bng pha lng- hi ca h ru ethylic - nc ti p sut p = 760 mmHg

x (phn mol)05102030405060708089,490100

y* (phn mol)033,244,253,157,661,465,469,975,381,889,489,8100

tsi10090,586,583,281,780,88079,47978,678,1578,478,4

IV . MC CH TH NGHIM. 1. Lm quen vi h thng chng luyn lin tc loi thp chp2. Nghin cu ch lm vic ca thp, tnh cn bng vt liu v nhit lng trong thp3. Xc nh s bc thay i nng ( s a l thuyt) v hiu sut ca thp.

V. S H THNG TH NGHIM (Xem hnh v)1. Thng cha hn hp u2. Lu lng k o nguyn liu u3. Bm nguyn liu u4. Lu lng k o lu lng hi lu5. Bm lng hi lu6. Thit b gia nhit nguyn liu u7. Thng cha sn phm8. Thp chng luyn 9. Thit b ngng t v hi lu10. in tr gia nhit sn phm hi luT1 - nhit k o nhit hn hp nguyn liu u vo T2 - nhit k o nhit nh thpT3 - nhit k o nhit y thpT4 - nhit k o nhit hi lu

V - van khng ch lng hn hp u

V - van khng ch lng hn hp y

V - van khng ch lng sn phm nh v lng hi lu

V - van nc lm lnh ngng t

V - van tho sn phm nh

V - van tho sn phm y

VI. TH T TIN HNH TH NGHIM .1. Kim tra :- H thng thit b th nghim theo s .- Cc dng c o : nhit k, th k, ru k, lu lng k, bnh cha vv 2. Chun b : - Nguyn liu u ( c nng theo yu cu)- Chy h thng gia nhit y thp - M van cho nc vo thit b ngng t hi lu

3. Khi nhit u y thp t n trn 100C, dung dch trong bnh cu bt u si thi ta m van V cho nguyn liu u vo thp ; ng thi cho chy h thng gia nhit nguyn liu u4. i cho sn phm nh xut hin th bt u khng ch lng hn hp u v lng hi lu sao cho n nh.5. Khi tt c cc thng s n nh ri th tin hnh o :

- Lng hi luu G (o 3 ln ly trung bnh )

-Lng sn phm nh P v nng ca n x(o 3 ln ly trung bnh )

- Lng nguyn liu u F v nng ca n x (o 3 ln ly trung bnh )

- Nhit sn phm y x(o 3 ln ly trung bnh ).- Nhit nh, y, a tip liu v nhit u vo.

6. Sau khi ly xong cc s liu th dng th nghim:

- Tt gia nhit nguyn liu u v ng van V ngng cung cp nguyn liu u.- Ngng gia nhit u v tt h thng in

- Nhit trung bnh cn gim cn 40 50 C, ng van nc V.7. Ghi cc s liu vo nht k th nghim, bo co vi cn b hng dn, lm v sinh sch s ni th nghim trc khi ra v.

VII. PHNG PHP TNH TON .1. Tnh cn bng vt liu. Tnh ging nh phn thp m2. Tnh cn bng nhit lng : tnh ging nh phn thp m, nhng ch l nhit ca lp cch nhit hai on thp khc nhau nn tn tht nhit ra mi trng xung quanh c khc nhau. n gin, ta coi nh khng c mt mt 3. Xc nh s bc thay i nng v hiu sut ca thp a. Xc nh s bc thay i nng ging nh phn thp m.b. Xc nh hiu sut ca thp

y : - s a l thuyt

- s a thc t( vi thp ny = 5 a)

BNG KT QU TH NGHIMS TTNhit u

t

(C)Nhit sn phm y

t (C)Nhit hn hp u vo thp t

(C)Nhit sn phm nh hi lu

t

(C)Nng sn phm nh

x(Phn mol)Nng sn phm nh

x(Phn mol)Nng sn phm nh

x(Phn mol)Lng hn hp u

V(ml/s)Lng hi lu

V(ml/s)Lng sn phm nh

V(ml/s)

1

2

3

Trung bnh

VIII. PHN BO CO TH NGHIM. 1. Mc ch th nghim2. S h thng th nghim 3. Tnh ton v bng kt qu4. Nhn xt th nghim.

BI 6 : TH NGHIM C CI. M u:1. nh ngha:C c l qu trnh lm bay hi mt phn dung mi ca dung dch cha cht tan khng bay hi nhit si ca dung dch nhm mc ch: Lm tng nng cht tan Tch cht rn ha tan dng tinh th Thu dung mi nguyn chtC c c th tin hnh p sut d, p sut thng hoc p sut chn khng, c th tin hnh lin tc hay gin on trong h thng thit b mt ni (mt thit b) hay nhiu ni theo s xui chiu, ngc chiu hay cho dng. Hi dung mi bay ra trong qu trnh c c ( thng l hi nc ) gi l hi th. Hi th thng c nhit cao, n nhit ha hi ln nn c s dng lm hi t cho cc ni c c ngay trong cng mt h thng.Phng php c c chn khng c c cc dung dch c nhit si cao v d b phn hy v nhit. Khi c c chn khng th nhit si ca dung dch gim, nn c th s dng c hi th ca ni c c trc lm hi t cho ni sau, lm tng hiu s nhit gia nhit d ca hi t v nhit si trung bnh ca dung dch, ng thi gim c tn tht nhit ra mi trng xung quanh.2. Cn bng vt liu ca h thng c c hai niK hiu:- G , Gc, W: Lng dung dch u, dung dch cui v lng hi th bay hi, kg/s.Phng trnh cn bng vt liu:G = Gc + W, kg/s(1)- xd, xc : nng cht tan trc v sau khi c c ( thng cha S1 v S2 ), phn khi lng ( %khi lng )Phng trnh cn bng vt liu ca h thng c c vit theo cht tan:G.x = Gc.xc , kg/s(2)T (1) v (2) xc nh c lng hi th bay hi c hai ni c c ( A v B ) l :W = G ( 1 x/xc ), kg/s(3)W = W1 + W2 , kg/s (4) y : W1, W2 : lng hi th bay hi ni A v ni B.W = G ( 1- x/xc ) (5)W2: c o bnh lng S1 ; y x1 : nng dung dch ra khi ni A.3. Cn bng nhit lng cho ni c c th nhtHnh 1. S cn bng nhit lng ca h thng c c hai niDo sn phn ca ni th hai (G2) c ly ra khng lin tc ( thng sau khi dng th nghim mi ly ra), chnh v vy bi th nghim ny, tnh cn bng nhit lng s c thc hin cho ni th nht,Phng trnh cn bng nhit lng ca ni th nht c dng:D.i + Gd.Gd.td = W1.i1 + G1.C1.tS1 + D.1.Cn + Qm1 + Qcd1(6)Lng nhit do hi t cp cho ni th nht:Q1 = D.( i1 Cn1) = D.r1(7)Trong :- D, i1, 1, Cn , r1: lng hi t, hm nhit hi t, nhit , nhit dung ring v n nhit ha hi ca nc ngng.- Gd, Cd, td : lng dung dch u, nhit dung ring v nhit dung dch u- W1, i1: lng hi th, hm nhit hi th- G1, C1, tS1: lng dung dch, nhit dung ring v nhit si ca dung dch i ra t ni 1- Qm1, Qcd1: lng nhit mt ra mi trng xung quanh v nhit c c ti ni mt( Qm1 + Qcd1 ) chp nhn bng 5% lng nhit cp cho qu trnh c c ti ni mt.T phng trnh ( 6 ) v ( 7 ) c th tnh c lng hi t cn thit D nhit Q1cp cho ni c c th nht.II. Mc ch v yu cu th nghim:1. Nm vng cu to, nguyn tc lm vic ca cc thit b v my trong s dy chuyn h thng c c hai ni 2. Tnh cn bng vt liu3. Tnh cn bng nhit lng ca ni th nht ( xc nh D v Q1 )III. S cu trc h thng c c hai ni:Hnh 2 : S cu trc ca h thng c cCh thch:1.- H thng c c hai ni xui chiu 2. - Thit b x l nc cng bngtrao i ion3. Ni hiIV. Trnh t tin hnh th nghim1. Chun b trc khi vn hnh h thng c c1.1. Tm hiu h thng Cc thit b chnh ( 2 ni c c A v B ). Cc thit b ph: bm ly tm, bm chn khng vng nc, thit b ngng t, ng tho nc ngng Cc thng cha dung dch H thng ng ng, van, kha H thng ph tr: ni hi, thit b x l nc cng bng phng php trao i ion1.2. Chun b vn hnh M van nc cp cho thit b trao i ion Tho bt mt phn nc trong ni hi ( nu y): m ng thi van x nc v van x kh trn ng ng dn hi t. Khi nc trong ni hi t mc cn thit, ng hai van li ng cc cu dao in cp in cho t in, ni hi v h thng c c. Kim tra p sut ni hi, khi vt qu 5at phi thay i gi tr t ca p sut hi bng cch chnh cc Rle p sut M van cp nc bm chn khng P2 Kim tra mc nc bnh cha nc ngng S3. Nu y phi tho ra ngoi. Ch nn li 1 lng nh nc ngng bnh S3.2. Vn hnh- Bm dich t thng cha nguyn liu u vo ni c c A bng bm P1, m van hi cho hi nng t ni hi sang un nng ni A- Cc thng s p sut, nhit s c hin th trn b iu khin bng tay. 3. Ly s liu- Ghi s liu v mc dung dch thng cha nguyn liu u S1 v bnh cha nc ngng S3 thi im bt u v kt thc. Nn ly thi im bt u o l thi im sau khi hi th ca ni B xut hin ( bt u thy xut hin nc ngng thit b ngng t). Thi gian th nghim ko di 30 40 pht. Lng hi th trong thng S3 c ly o bng ng ong- Ly mu dung dch: dung dch ban u c th ly bt k thi im no qua van VS1, cn dung dch ra khi ni A (van VS2) v ni B (van VS3) ch ly sau khi dng h thng. Nng cc dung dch c o bng chit quang k.4. Kt thc th nghim- Sau khi kt thc qu trnh c c, cn: ng van cp hi t Bm dung dch trong ni B v thng cha sn phm S2 hoc bm tun hon dung dch trong c hai ni v thng cha dung dch u S1: Ph chn khng trong cc ni c c bng van V11, V12 Khi bm v S2: m van V9, V14, khi ng bm P4 bng cch nhn vo biu tng bm hi dung dch- Ghi s nht k th nghim: thi gian, nhm, lp, danh sch nhm, cc s liu th nghim5. X l khi gp s c- Khi p sut trong ni hi cao qu mc cho php m Rowle khng t ngt, cn tt in ni hi- Khi c s c trong h thng c c cn phi tt ngay cu dao tng- Bo co vi cn b th nghim nhng hin tng khng bnh thng, khng c t tin x l nu khng c php.

V. Kt qu th nghim v tnh ton:1. Kt qu th nghim:Thi gianMc dung dch trong bnh S1x 10Nng % khi lngMc nc ngng t trong bnh S3(lt)

( s)Khi bt u S10Khi kt thc S11xx1x2Khi bt u S30Khi kt thc S31

- Nhit , p sut hi t ti ni mt: T1 = .(oC); P1= (at)- Nhit dung dch u: T = .(oC)- Nhit , p sut hi th ti ni mt: Tht1 = .(oC); Pht1= ...(at)

2. Tnh ton cn bng vt liu- Lng dung dch u i vo h thng c c:G = ((S10 S11). 10.)/ , kg/s( 8 )S1 l cao bnh, dm. ng vi din tch mt thong 10 dm2. : khi lng ring ca dung dch, kg/lt S tay tp I, hoc dng t trng k o.- Lng nc ngng t thu c:W2 = ( S3. nc)/ , kg/s ( 9 )S3 th tch nc ngng, lit (dm3).nc = 1kg/lt.- Tnh W Tng lng hi th bay hi trong thi gian c c theo pt( 3 ).- Tnh W1 lng hi th bay hi sau thi gian c c ni A theo phng trnh (4) ( W1 c th tnh kim tra theo phng trnh (5)- Tnh nng dung dch ra khi ni A theo phng trnh :X1 = G.x/ (G W1) ( 10 )3. Tnh cn bng vt liu ca ni mt- Tra cu hn nhit ( i ) ca hi t v hi th theo nhit - Tra cu nhit si, nhit dung ring ca dung dch trong ni mt, cn c vo nng X1 o c.- Xc nh lng hi th bay ra ni mt ( W1 )- Tnh lng hi t D theo phng trnh ( 6 )- Tnh lng nhit Q1 cp cho ni c c th nht theo phng trnh (7)4. Nhn xt th nghim

H THNG C C 2 NI( Hng dn s dng)S h thng thit b c c IC17/2D:A, B Ni c cC Thit b lm lnh.P1 Bm ti hn hp u, bm sn phm c cP2 Bm chn khng vng ncP3 Bm cp nc vo ni hiS1 thng cha hn hp u cn c cS2 thng cha sn phm c cS3 Thng cha lng hi th ni B ngng t T1, T2 can nhit hin th nhit ni A, ni B AP1, AP2, AP3 ng h o p sut ni A, ni B, ni hiCc vanVV1 - Van hi vo ni AVV2 Van hi vo ni BVV3 Hi th t ni A sang ni BVS1 van ly mu hn hp u cn c c.VS2 van ly mu sn phm c c sau ni AVS3 van ly mu sn phm c c ni B.C1, C2 Cc tho nc ngng ni A, ni BV1 van cho hn hp u vo ni c c A.V2 van cho hn hp u vo ni c c B .V3 van tho sn phm c c sau ni A.V4 van tho sn phm c c sau ni B.V5 Van iu chnh ht dch ni AV6 Van iu chnh ht dch ni BV7 Van cp dch vo thng cha nguyn liu uV8 Van cp dch vo thng cha sn phmV9 Van x y thng cha sn phm c cV10 Van x y thng cha nguyn liu uV11 Van x p ni AV12 Van x p ni BV13 Van tit luV14 Van x nc ngng ni BV15 Van iu chnh lng hi vo bm chn khng.

Th nghim QTTB-i Hc B Ra Vng TuPage 32