n: Tnh ton thit k thit b thng quay sy bp ht 2000kg nguyn liu/h GVHD:Tin Tin Nam

MC LC

CHNG 1: TNG QUAN6CHNG II: QUY TRNH CNG NGH20CHNG III:TNH TON THIT B SY21CHNG 3: KT LUN69CHNG 4 : TI LIU THAM KHO70

DANH MCBng:Bng 1.1: thnh phn ha hc gn ng cc thnh phn chnh ca ht ngBng 1.2: Tnh hnh sn xut ng trn th gii giai on 1997-1999Bng 1.3: Tnh hnh sn xut ng cc vng thuc cc chu lc1997-1999Bng 1.4: Tnh hnh sn xut ng theo vng v a phng (nm 2000)Bng 3.1: Cc thng s ca tc nhn sy trong qu trnh sy l thuytBng 3.1: Cc thng s ca tc nhn sy trong qu trnh sy thc tBng 3.3: Lu lng th tch ca tc nhn syBng 3.4: Cc thng s vt liu ch to thng syBng 3.5:Thnh phn nhin liu than s dngBng 3.6: Thng s vt l ca cht ti nhit (khi l)Bng 3.7: kch thc cyclonBng 3.8: Cc thng s hnh hc ch yu ca b truynBng 3.9: Bng thit k ng ngBng 3.10: Kt qu tnh tr lc ma st trn ng ngBng 3.11: kch thc cyclon n H-15Bng 3.12: T s v cng sut truyn ngBng 3.13: Thng s b truynBng 3.14: Bng thit k ng ngBng 3.15: Kt qu tnh tr lc ma st trn ng ngBng 3.16: Kt qu tnh tr lc cc b ( t m)Bng 3.17: bng tnh cng sut v chn qut trn trc ng chnhBng 3.18: bng tnh cng sut v chn qut trn ng ng dn khiBng 3.19: Thng s qutHnh: Hnh 1.1: Ng Hnh 1.2: Ng rng ngaHnh 1.3: Ng npHnh 1.4: Ng ngHnh 1.5: Ng nHnh 1.6: Ng btHnh 1.7: Ng bcHnh 1.8: Ht ngHnh 1.9: S nguyn l thit b thng quayHnh 2.1: S quy trnh sy bp htHnh 3.1: cnh o trnHnh 3.2: Chiu cao lp hthnh 3.3: Cc ng caloriferHnh 3.4: Kch thc caloriferHnh 3.5: Bung ha trnHnh 3.6: Kch thc cyclonHnh 3.7: B truyn ngHnh 3.8: Kch thc vnh aiHnh 3.9: Con ln Hnh 3.10: Kch thc qut ly tmHnh 3.11: t mHnh 3.12: t thuHnh 3.13: ng cong tit din trnHnh 3.14: ng cong tit din ch nht

NHN XT CA GIO VIN HNG DNNHN XT CA HI NGCHNG 1: TNG QUAN

Sy l mt qu trnh cng ngh c s dng rt nhiu trong thc t sn xut v i sng. Trong cng nghip nh ch bin nng sn, hi sn, ch bin g k thut sy ng mt vai tr quan trng trong dy chuyn sn xut. Trong nng nghip, sy l mt trong cc cng on quan trng trong cng ngh sau thu hoch i vi cc loi nng sn. Thc t cho thy nu phi kh hoc sy khng kp, nhiu nng sn c th b mt mt do m mc v bin cht (chim khong 1020%, i vi mt vi loi c th ln n 4050%). Ngoi ra, sy cn l qu trnh cng ngh quan trng trong ch bin nng sn thnh thng phm. Trong n mn hc ny, em s trnh by v quy trnh cng ngh v thit k thit b sy thng quay sy bp ht vi nng sut 2000 kg/h.

I. Tng quan1. nh ngha v sy Sy l qu trnh dng nhit nng lm bay hi nc ra khi vt liu. Qu trnh sy c th tin hnh t nhin bng nng lng t nhin nh nng lng mt tri , nng lng gi (gi l qu trnh phi hay sy t nhin).Dng cc phng php ny ch tn nhit nng nhng khng ch ng diu chnh c vn tc ca qu trnh theo yu cu k thut sy, nng sut thp. Bi vy trong ngnh cng nghip ngi ta thng tin hnh qu trnh sy nhn to bng ngun nng lng do con ngi to ra. Ty theo phng php truyn nhit, trong k thut sy cng chia ra: Sy i lu: Phng php sy cho tip xc trc tip vt liu sy vi khng kh nng khi l (tc nhn sy). Sy tip xc: Phng php sy khng cho vt liu sy tip xc trc tip vi tc nhn sy. Sy bng tia hng ngoi: Phng php sy dng nng lng ca tia hng ngoi, do ngun nhit pht ra truyn cho vt liu sy Sy bng dng in cao tn: Phng php sy dng nng lng in trng c tn s cao t nng trn ton b chiu dy lp vt liu Sy thng hoa: phng php sy trong mi trng c chn khng rt cao, nhit thp nn m t do trong vt liu ng bng v bay hi t trng thi rn thnh hi khng qua trng thi lng. Ba phng php sy cui cng t c s dng trong cng nghip nn gi chung l cc phng php sy c bit. Sy i lu c s dng ph bin trong cng nghip. Cc dng thit b sy i lu : TBS bung TBS hm TBS thp TBS thng quay TBS phun TBS kh ng TBS tng si

2. Nguyn liu bp(ng)a. Tng quanNg c tn khoa hc l: Zea mays L. Gii: Plantae. Ngnh: Magnoliophyta. Lp: Liliopsida (Monocotyledones). B: Poales (b Ha tho, b c, b la). H: Gramineae (h Ha tho), Poaceae. Chi: Maydeae Loi: Zea mays L, Z.mexicana, Z.perrenis L

Ng l cy lng thc quan trng trn ton th gii bn cnh la m v la go. cc nc thuc Trung M, Nam v Chu Phi, Ngi ta s dng ng lm lng thc chnh cho ngi vi phng thc rt a dng theo vng a l v tp qun tng ni.

Ng l cy thc n chn nui quan trng nht hin nay: 70% cht tinh trong thc n tng hp ca gia sc t ng. Ng cn l thc n xanh v v chua l tng cho i gia sc c bit l b sa. Gn y ng cn l cy thc phm. Ngi ta dng bp ng bao t lm rau cao cp v n sch v c hm lng dinh dng cao. Ng np, ng ng c dng lm qu n ti hoc ng hp lm thc phm xut khu. Ng cn l nguyn liu ca ngnh cng nghip lng thc thc phm v cng nghip nh sn xut ru, cn, tinh bt, du, glucose, bnh ko

Chnh v tm quan trng ca n trong neeng kinh t nh vy, cho nn cy ng c ton th gii gieo trng v hnh thnh 4 vng sinh thi cy ng chnh l: vng n i, vng cn nhi i, vng nhit i cao v vng nhit i thp. Vit Nam nm trong vng nhit i thp. Cy ng c a vo sn xut cch y 300 nm. Nhng nm gn y, nh c cc chnh sch khuyn khch ca nh nc v c nhiu tin b khoa hc k thut, c bit l v ging, cy ng c nhng tng trng ng k v din tch, nng xut v sn lng, ng thi hnh thnh 8 vng trng ng chnh trong c nc.

b. Phn loi

T loi Zea mays L, da vo cu trc ni nh ca ht, ng c phn loi thnh:

Ng (Zea mays L. subsp. Indurata sturt)

Hnh 1.1: Ng

Ng rng nga ( Zea mays L. subsp. indentata sturt)

Hnh 1.2: Ng rng nga

Ng np ( Zea mays L. subsp. ceratina kulesh)

Hnh 1.3: Ng np

Ng ng ( Zea mays L. subsp. saccharata sturt)

Hnh 1.4: Ng ng

Ng n ( Zea mays L. subsp. everta sturt)

Hnh 1.5: Ng n

Ng bt ( Zea mays L. subsp. amylacea sturt)

Hnh 1.6: Ng bt

Ng bc ( Zea mays l. subsp. tunecata sturt)

Hnh 1.7: Ng bc

c. Cu to Cc c quan sinh dng ca bp gm: r, thn, l lm nhim v duy tr i sng ca cy bp. Phi v ht l khi thy ca cy mm. Cc c quan sinh sn c (bng c) v ci (mm bp) khc bit nhau nhng nm trn cng mt cy. Ng giao phn cho nh gi v cn trng. Khi thu hoch, con ngi s dng ht ng lm thc phm. Ht ng thuc loi qu dnh gm 4 b phn chnh: v ht, lp aleron, phi, ni nh v chn ht. V ht (chim 69% khi lng ht ng): l mt mng nhn bao bc xung quanh ht c mu trng, mu tm hoc vng ty thuc vo ging. Lp aleron (68%): nm sau v ht bao bc ly ni nh v phi. Ni nh (7085%): l b phn chnh cha y cc cht dinh dng nui phi. Ni nh cha tinh bt. Tinh bt ni nh gm 3 loi: bt, sng v pha l. c im v mu sc ni nh l cn c phn loi ng. Phi (815%): bao gm l mm, tr di l mm, r mm, v chi mm. Phi ng chim gn 1/3 th tch ht, bao quanh phi c lp t bo xp gip cho vn chuyn nc vo phi v ngc li thun li. Chn ht: gp ht nh cht vo bp ng.Thnh phn ha hc ca ht ng c cho trong bng sau:

Bng 1.1: thnh phn ha hc gn ng cc thnh phn chnh ca ht ng (%)Thnh phn ha hcV htNi nhMm

Protein3.78.018.4

Cht bo1.00.833.2

Cht x th86.72.78.8

Tro0.80.310.5

Tinh bt7.387.68.3

ng0.340.6210.8

Theo ngun: Watson, 1987 (theo Ng Ngun dinh dng ca loi ngi, FAO, 1995)

Hnh 1.8: Ht ng

1 v 2: Ht ng b dc theo 2 mt: a.Vt so ru ng, b.V ht, c.Lp aleron, d.Ni nh, e.Thun (ng),f.Lp tuyn ngi, g.Bao l mm, h.Chi mm, i.Lng u tin,j.R mm th sinh, k.t ng, l.R mm, m.Bao mm,n.T bo y ni nh, o.Lp en, p.Chn ht3: Lt ct qua v ht v ni nh:a.V ht, b.Mng phi, c.Lp aleron, d.t bo ngoi ca ni nhe.T bo trong ni nh4: Lt ct qua ng: a.Lp tuyn ng, b.T bo trong5: Lt ct dc vng y ni nh:a.T bo ni nh thng, b.T bo ni nh mng y, c.Lp en

d. Tnh hnh sn xut ng trn th gii Ng l cy lng thc quan trng trong nn kinh t ton cu. Mc d ch ng th ba v din tch ( sau la nc v la m) ng c nng sut v sn lng cao nht tng cc cy cc. Giai on 1997-1999, din tch trng ng l 140.182triu ha, nng sut 4.3 tn/ha v tng sn lng 600.27 triu tn (CIMMYT 1999/2000). Mc tng trng bnh qun hng nm ca cy ng trn ton th gii v din tch l 0.7%, nng sut l 2.4% v sn lng l 3.1%.

Theo CIMMYT 1999/2000, mt s ch tiu v tnh hnh sn xut ng trn th theo cc khi kinh t c trnh by bng sau:

Bng 1.2: Tnh hnh sn xut ng trn th gii giai on 1997-1999Ch tiuTon th giiCc nc ang pht trinCc nc pht trinng u v Lin X c

Din tch (1000 ha)140.18296.06234.5439.577

Nng sut (tn/ha)4.32.98.33.8

Sn lng(1000 tn)600.277276.325287.33536.617

Phn trm din tch ng trong cy ng cc(%)2021259

Nhp khu (1000 tn)-24.426-25.749-544

Bnh qun u ngi (kg/nm)1006628288

Lm lng thc cho ngi(%)173047

Lm thc n chn nui(%)66577682

Bng 1.3: Tnh hnh sn xut ng cc vng thuc cc chu lc giai on 1997-1999Ty u, Bc M34.5438.3287.3352525.749282476

.u v Lin X c9.5773.836.6179-54488782

Nam M15.5013.250.10753-8.744190977

Vng ANDET2.0821.94.013453.967734744

Mexico Trung M9.6012.221.084706.7221665628

ng 25.5924.8122.7842710.3261001275

ng Nam 8.1852.419.974193.080504346

Nam 8.1471.713.66062410755

Ty 1.1053.53.87634.101342369

Bc Phi1.1925.46.402104.892744544

Ty Trung Phi9.2231.211.03521184436613

Ty .Nam Phi15.4361.523.38941127817217

Ch tiuDin tch (1000 ha)Nng sut (tn/ha)Sn lng (1000 tn)Phn trm din tch ng trong cy ng cc(%)Nhp khu (1000 tn)Bnh qun u ngi (kg/nm)Lm lng thc cho ngi(%)Lm thc n chn nui(%)

e. Tnh hnh sn xut ng Vit Nam

Cy ng a vo Vit Nam cch y khong 300 nm. Ngy nay ng c trng tt c cc vng v cc tnh nc ta, song do yu t t ai, thi tit kh hu chi phi nn nng sut c s khc bit r rt. Bng 3 s cho chng ta khi qut v tnh hnh sn xut ng ca cc vng sinh thi v cc tnh nm 2000.

Bng 1.4: Tnh hnh sn xut ng theo vng v a phng (nm 2000)

Vng, tnhDin tch (1000 ha)Nng sut (t/ha)Sn lng (1000 tn)

C nc730.227.52005.9

B Sng Hng92.931.1279.6

H Ni12.126.231.7

Hi Phng0.630.01.8

Vnh Phc20.127.354.9

H Ty20.633.569.0

Bc Ninh4.426.311.5

Hi Dng5.237.319.4

Hng Yn7.226.519.1

H Nam7.929.523.3

Nam nh3.432.110.9

Thi Bnh4.740.619.1

Ninh Bnh6.728.218.9

g Bc183.223.6425.5

H Giang41.817.271.7

Cao Bng31.524.175.8

Lo Cai22.517.038.3

Bc Cn9.921.421.2

Lng Sn12.735.344.8

Tuyn Quang11.733.038.6

Yn Bi9.919.719.5

Thi Nguyn10.728.830.8

Ph Th16.226.242.5

Bc Giang11.425.829.4

Qung Ninh4.926.312.9

Ty Bc104.221.9227.8

Lai Chu31.113.943.2

Sn La51.626.3135.8

Ha Bnh21.522.748.8

Bc Trung B92.824.5227.4

Thanh Ha46.427.3126.7

Ngh An37.521.078.7

H Tnh2.523.25.8

Qung Bnh3.331.510.4

Qung Tr1.916.33.1

Tha Thin Hu1.222.52.7

Duyn hi NTB28.525.171.6

Nng0.160.00.6

Qung Nam8.929.826.5

Qung Ngi7.732.324.9

Bnh nh2.833.99.5

Ph Yn4.07.02.8

Khnh Ha5.014.67.3

Ty Nguyn86.836.5320.3

Kon Tum4.429.813.1

Gia Lai23.527.564.7

k Lk46.541.6193.5

Lm ng12.439.549.0

ng Nam B122.833.4401.9

TP.H Ch Minh1.130.93.4

Ninh Thun10.818.620.1

Bnh phc5.926.315.5

Ty Ninh7.135.425.1

Bnh Dng1.316.22.1

ng Nai65.335.7232.9

Bnh Thun12.028.834.6

B Ra Vng Tu19.335.368.2

B Sng Cu Long19.027.351.8

Long An0.432.51.3

ng Thp2.640.410.5

An Giang5.120.610.5

Tin Giang2.524.86.2

Vnh Long0.620.01.2

Bn Tre0.827.52.2

Cn Th1.132.73.6

Tr Vinh2.629.67.7

Sc Trng2.724.86.7

Bc Liu0.326.70.8

C Mau0.336.71.1

Theo ngun: Nin gim thng k 2001

3. Phng php thc hin qu trnh sy:

bo qun hoc dng ch bin cc sn phm c cht lng cao th cc loi ht cn c sy kh xung m bo qun hoc m ch bin. thc hin qu trnh sy, c th s dng nhiu h thng sy khc nhau nh: h thng sy hm, h thng sy thng quay, h thng sy thp, h thng sy tng si Mi ch cng ngh sy khc nhau s c nhng nh hng khc nhau n cht lng ca sn phm.

sy bp ht, ngi ta c th dng thit b sy thp, sy thng quay. y, ta dng thit b sy thng quay, l thit b chuyn dng sy ht. Loi thit b ny c dng rng ri trong cng ngh sau thu hoch sy cc loi ng cc. Trong h thng ny, vt liu sy c o trn mnh, tip xc nhiu vi tc nhn sy, do trao i nhit mnh, tc sy nhanh, v ng u ca sn phm cao. Ngoi ra, thit b cn c th lm vic vi nng sut ln.

Tc nhn sy s dng l khng kh, c gia nhit bi calorifer vi cht ti nhit l khi l c to ra t qu trnh t than.

Nguyn liu bp l mt nguyn liu cha rt nhiu tinh bt. Ch cng ngh sy tinh bt li ph thuc rt nhiu vo nhit h ha sn phm. Nhit h ha ca tinh bt khong 65C, do ta cn chn nhit tc nhn sy ph hp, khng cao nhng cng khng qu thp, mc ch l y nhanh qu trnh sy, v khng lm cho nhit ca nguyn liu vt qu nhit h ha.

i vi thit b sy thng quay:H thng sy thng quay l h thng sy chuyn dng sy ht, cc nh. N c dng rng ri trong cng ngh sau thu hoch sy cc loi ng cc. Cu to chnh ca h thng sy thng quay l mt thng sy hnh tr trn. Thng sy c t nghing vi mt phng nm ngang theo t l 1/151/50. Thng sy quay nh mt ng c in thng qua mt hp gim tc. Vt liu sy th pheux sy i vo thng sy cng vi tc nhn. Thng sy quay trn, vt liu sy xa b o trn va i dn t u cao ca thng xung u thp. Trong qu trnh ny, tc nhn sy v vt liu sy trao i nhit m cho nhau. Vt liu i ht chiu di thng sy c ly ra v vn chuyn vo kho cha nh mt bng ti cn tc nhn sy di qua xyclon thu hi vt liu sy hay bi trc khi thi ra mi trng.

Hnh 1.9: S nguyn l thit b thng quay

tng cng qu trnh xo trn v qu trnh trao i nhit m ngi ta b tr trong thng sy cc cnh khuy. C rt nhiu cch b tr v nhiu loi cnh khuy khc nhau. Trong khun kh ti ny, nhm chn loi cnh nng.

Thit b sy thng quay c: u im: qu trnh sy u n, din ra mnh lit nh tip xc tt gia vt liu sy v tc nhn sy. Cng sy ln, c th t 100 kg m/m3h. Thit b nh gn, c th c kh ha v t ng ha hon ton. Nhc im: vt liu b o trn nhiu nn d to bi do v vn, v hao tn vt liu dn n nng sut khng cao, v lm gim cht lng sn phm.

CHNG II: QUY TRNH CNG NGHBp

Thu hoch

V

Bc v

Phi s b

Ci bp

Tch ht

Sy

Lm ngui

ng gi

Sn phm

Hnh 2.1: S quy trnh sy bp htCHNG III:TNH TON THIT B SY

Vt liu sy l bp ht, c cc thng s vt l c bn nh sau: m ban u ca vt liu sy (theo vt liu t):1 = 25% m cui ca vt liu sy (theo vt liu t):1 = 14% Khi lng ring ht vt liu:r = 1,253 kg/m3(Bng 2.4/47[2]) Khi lng ring khi ht:r = 850 kg/m3(Ph lc 4/230[3]) Nhit dung ring ca vt liu kh:Ck = 1.2 1.7 kJ/kg.K(Trang 20[1])Chn Ck = 1.5 kJ/kg.K Kch thc ht bp: (Ph lc 7/351[1]) Di:l = 5.2 14 mm. Rng:b = 5 11 mm. Dy: = 3 8 mm. ng knh tng ng: dt = 7.5 mm. Nng sut nhp liu: G1 = 2,000 kg/h.I. Tnh cn bng vt cht:Ta k hiu cc i lng nh sau:G1, G2 (kg/h):khi lng vt liu sy i vo, ra thit b sy.1, 2(%): m tng i ca vt liu sy u vo, ra ca thit b sy.W(kg/h):lng m bay hi trong 1 gi.Gk(kg/h):khi lng vt liu kh tuyt i.d0 (kg m/kgkk) : cha m (hm lng hi m) ca tc nhn sy ban u.(kg m/kgkk) : cha m (hm lng hi m) ca tc nhn sy ra.

Phng trnh cn bng vt cht:

(Trang 127[1])

Lng m bc hi trong 1 gi:

Lng vt liu kh tuyt i:

Gk = 2,000(1-0,25) = 1,500 (kg/h)

Nng sut ca sn phm sy: G2 = G1 W = 2000 255.81 =1744.19 (kg/h)

II. Tnh cn bng nng lng1. Cn bng nng lng cho thit b sy l thuyt:Cng thc xc nh cc thng s ca tc nhn sy: p sut hi bo ha:

(CT 2.31/31[1]) cha m:

(kg m/kg kk)(CT 2.18/28[1])

(bar)Pa = 0.981 (bar)= 0.981 x 105 N/m2: p sut kh quyn. Enthalpy:

(CT 2.24/29[1])Trong :ik, ia (kJ/kg) :enthalpy ca 1kg khng kh kh v 1kg hi nc.Cpk = 1.004(kJ/kg.K):nhit dung ring ca khng kh kh.Cpa = 1.842(kJ/kg.K):nhit dung ring ca hi nc. r = 2,500(kJ/kg):n nhit ha hi ca nc.

(kJ/kg)

Th tch ring:

(CT VII.8/94[6])Trong , Pa, Pb: p sut kh tri v phn p sut bo ha ca hi nc trong khng kh, N/m2.

a. Thng s trng thi ca khng kh ngoi tri (A):

Khng kh ngoi tri (a im sy: Bnh Dng) :

(kgm/kgkk)

Khng kh c qut a vo calorifer v c t nng ng m (x1=x0) n trng thi B (x1, t1). Trng thi B cng chnh l trng thi ca tc nhn sy vo thng sy. Nhit t1 ti im B l nhit cao nht ca tc nhn sy trong thng sy, do tnh cht ca vt liu sy v ch cng ngh quy trnh. Nhit ca tc nhn sy B c chn phi thp hn nhit h ha ca tinh bt bp. Do bp l lot ht giu tinh bt, ban u khi m ca vt liu sy cn cao, nu vt liu tip xc vi tc nhn sy nhit cao th lp b mt ca ht tinh bt b h ha v to thnh mt lp keo mng bt kn b mt thot m t trong lng vt liu ra ngoi.

Quy tc sy i vi loi nguyn liu cha lng tinh bt v lng m cao th nn sy nhit thp, nhit h ha tinh bt bp trong khong 62 700C, v vy ta cn sy nhit N, do tha iu kin cn quay thng.

b. Chn t s truyn ng:

T s truyn ng chung ca h thng: Do t s truyn ca ng c ln, nn cn phi s dng b gim tc cho ng c. y, ta s dng hp gim tc trc vt bnh rng. Cu to ca hp gim tc nh hnh v:Chn cc t s truyn:i12 = 4i23 = 6T s truyn t ng c sang trc vt: S vng quay ca cc trc: Cng sut cn quay thng: N = = = 1.819 (kW)Cng sut cc trc: Hnh 3.7: B truyn ng

Trong , theo bng 21/27[8], chn hiu sut cc b truyn nh sau: B truyn bnh rng tr h: h = 0.93. B truyn bnh rng tr kn: kn = 0.96. B truyn trc vt: Ta c bng kt qu sau:Bng 3.12: T s v cng sut truyn ngTrc ng cIIIIII

i 3064

n (vng/pht)7202461

N (kW)1.8191.6551.5881.477

c. Tnh b truyn bnh rng:

B truyn ny c chc nng truyn ng t tang dn ng n bnh rng ln gn vo thng. y l s truyn ng gia 2 trc song song, do ta chn b truyn bnh rng tr rng thng, n khp ngoi, truyn ng h.

Chn vt liu ch to bnh rng:Chn nhm bnh rng c rn HB 350, c ct gt chnh xc sau nhit luyn (do rn tng i thp), khng i hi phi qua cc nguyn cng tu sa t tin nh mi, mi nghin Bnh rng c kh nng chy mn tt. trnh dnh b mt lm vic ca rng, ly rn ca bnh rng nh ln hn bnh rng ln 3050HB, chn mc thp bnh nh khc bnh ln.

Bnh rng ln: (Bng 38/40[8]) Vt liu:thp C35 thng ha. rn: HB = 160 Gii hn bn ko:b = 480 N/mm2 Gii hn chy:ch = 240 N/mm2

Bnh rng nh: Vt liu:thp C45 thng ha. rn: HB = 190 Gii hn bn ko:b = 580 N/mm2 Gii hn chy:ch = 290 N/mm2

Xc nh ng sut un cho php:i vi rng lm vic mt mt:(CT 35/42[8])Trong : 1 (N/mm2): gii hn mi un. Thp C45: Thp C35: n: h s an ton. i vi bnh rng bng thp rn thng ha, chn n = 1.5. k: h s tp trung ng sut chn rng. i vi bnh rng lm bng thp thng ha, chn k = 1.8.ng sut un cho php ca: Bnh rng nh: Bnh rng ln:Chn h s ti trng:K = 1.31.5.Do ta s dng b truyn ch to bng vt liu c kh nng chy mn, vn tc thp, nn chn h s ti trng K = 1.3.

Chn chiu di tng i ca rng:i vi b truyn bnh rng tr rng thng, trc v tng i cng (HB 350), theo bng 317/51[8]:Trong :b (mm): chiu rng bnh rng.m (mm): moun ca bnh rng.Chn m = 20.

Chn s rng v h s dng rng:Chn s rng ca bnh rng nh (bnh rng dn ng) Z1 = 36 (rng).Theo bng 318/52[8], chn h s dng rng y1 = 0.4135.

Tnh moun ca bnh rng:

(CT 329/51[8])Chn moun ca bnh rng tr theo tiu chun (Bng 31/34[8]): m = 10 mm.

Xc nh khong cch trc A, s rng v chiu rng bnh rng:Khong cch trc c xc nh theo cng thc sau:(CT 322/49[8])

Chn khong cch trc gia 2 bnh rng A = 1000 mm.

S rng bnh dn (nh) :Z1 = = 40 (rng) (CT 324/49[8])S rng bnh b dn (ln): Z2 = i Z1 =4 40 =160(rng)Chiu rng bnh rng dn: Chiu rng bnh rng b dn: b = 200 10 = 190 (mm)

Kim nghim sc bn un rng:(CT 333/49[8])H s dng rng y c xc nh theo bng 3-18/52[8]: Bnh rng nh:y = 0.4135 Bnh rng ln:y = 0.5170ng sut un ti chn rng bnh nh:

ng sut un ti chn rng bnh ln:

Vy bnh rng tha iu kin bn un ca rng.

Cc thng s hnh hc ch yu ca b truyn:Gc n khp: = 20.

Bng 3.13: Thng s b truynSTTThng sK hiu n vCng thc tnhBnh rng dn (nh)Bnh rng b dn (ln)

1Mounm (mm)10

2S rngZ (rng)40160

3ng knh vng lndl (mm)4001,600

4Khong cch trcA (mm)875

5Chiu rng bnh rngb (mm)200190

6ng knh vng nh rngDe (mm)4101,620

7ng knh vng chn rngDi (mm)3251,375

8Chiu cao u rnghd (mm)10

9Chiu cao rngH22.5

Tnh lc tc dng ln trc: (khng xt lc ma st)Moment xon Mx: (CT 353/55[8])Lc vng P: (CT 349/54[8])Lc hng tm Pr : Lc dc trc i vi b truyn bnh rng tr rng thng: Pa = 0.

Khi lng bnh rng:Bnh rng lm bng thp C35, = 7,850 kg/m3.

2. Tnh vnh ai:Chn s b cc thng s ca vnh ai nh sau: B rng ca vnh ai: B = 100 mm. B dy vnh ai l hiu gia bn knh ngoi v bn knh trong ca vnh ai. i vi thng ti trng nng, b dy vnh ai xc nh nh sau:Ta chn h = 40 mm. Vt liu lm vnh ai: thp CT3, = 7850 kg/m3.Gn lp vnh ai: Chiu cao: h1 = 70 mm. B rng: h2 = 40 mm. Chn : Hnh 3.8: Kch thc vnh ai

Chiu cao: h3 = 80 mm. B rng: h4 = 90 mm.

ng knh ngoi vnh ai:

Dai = (1,500 + 2 8) + 2 (100 + 40) = 1,796 (mm)

Khi lng 2 vnh ai: (xem vnh ai c dng vnh khn)

3. Tnh con ln :

Khi lng ca thng quay:mthng = = 7,900 ( - ) t = 7,900 () 7.5 = 2,245.6 (kg)Ti trng ca thng:

Chn gc gia 2 con ln l 2 = 60 = 30.Phn lc ca mi con ln ln vnh ai:

(CT 527/245[11])Phn lc T gm 2 thnh phn: Lc y con ln trt theo phng ngang:

S = T =39,754.66 sin 300 =19,877.33 (N)Hnh 3.9: Con ln

Lc p gi con ln ln b:N = T cos = 39,754.66 cos 300 = 34,428.55 (N)

B rng con ln :(CT 534/245[11])ng knh con ln bng thp:

dc (CT 536/245[11])

Mt khc:0.25 Dai dc 0.33 Dai=> 0.25 1,796 dc 0.33 1,796 (CT 537/245[11])=> 449 dc 592.68 (mm)Vy chn ng knh con ln dC = 500 mm.

4. Tnh con ln chn:

Lc dc thng U c xc nh nh sau:Lc U c khuynh hng ko thng tt xung, do ta t con ln chn st vnh ai gia thng v tr n nh. Trn thng quay, ta lp hai con ln chn nm v hai pha ca vnh ai t gn bnh rng vng.i vi thng c kch thc ln v nng, ta lm con ln chn mt nn.Khi lp t, lp sao cho trc con ln vung gc vi mt t.

Gc nghing ca con ln:Trong d: ng knh con ln chn. = 1.5: gc nghing ca thng quay.Chn d = 40 mm.Lc ln nht tc dng ln con ln chn:Trong , f l h s ma st gia vnh ai v con ln chn, chn f = 0.1.5. Tnh gu ti nhp liu:

Ta chn c cu nhpliu bng gu ti v chng c nhng u im sau: cu to n gin, kch thc gn, c kh nng vn chuyn vt liu ln cao ln, nng sut cao. Do vt liu sy l bp ht c ng knh trung bnh 7.5 mm, dng ht, hi m; ta chn gu ti bng vn tc cao, gu nng, gn c nh. Bp l vt liu c b mt ma st nh, do ta chn phng php nhp liu nh sau: vt liu xung y gu, dng gu mc, vn chuyn ln trn.

a. Chn cc chi tit c bn ca gu ti:

B phn ko:Bng c lm bng vi cao su. Chn chiu rng bng l 400mm, theo bng 5.9/227[12], chn s lp vi z = 5 (do vt liu dng ht).

Gu:Chn loi gu nng y trn c cc kch thc c bn sau: (Bng 5.10/228-[12])A = 175 mmB = 320 mmh = 190 mm: chiu cao ca gu.R = 55 mmi = 4.05 m3: dung tch 1 gu.Cc gu y trn c lp trn b phn ko cch nhau mt khong:

a = (2.5 3)h = 2.8190 = 532 (mm) (CT 5.21/229-[12])Khi bt gu vo bng, ta dp lm phn kim loi xung quanh l bt vt, khi ghp gu vi bng, mt bng v u bulng nm trn mt phng, nh vy bng s m kht vi tang.Tang dn ng:Tang ca gu ti bng c ch to bng cch hn. ng knh tang c xc nh:D = (125 150)z = 1405 = 700 (mm) (CT 5.22/229-[12])

Chn ng knh ca tang theo tiu chun D = 800 mm.Theo bng 5.11/230[12], chn chiu di tang L = 450 mm.

b. Xc nh nng sut v cng sut ca gu ti:Nng sut ca gu ti:

(CT 5.25/232-[12])Trong :v = 3 m/s:vn tc ca c cu ko bng bng. (Bng 5.12/233-[12]) = 850 kg/m3:khi lng ring ca vt liu. = 0.7: h s cha y vt liu trong gu, cho vt liu dng ht.

(tn/h)

Cng sut ca gu ti:Cng sut cn thit ca ng c truyn chuyn ng cho gu ti dng bng:

(CT 5.26/233-[12])Trong :H = 4m:chiu cao nng vt liu ca gu ti. = 0.7: hiu sut ca gu ti bng, i vi H 30m. (Bng 5.13/233-[12]) X. Thit k v tnh tr lc ng ng: Do h thng sy di, c tr lc ln, nn ta s dng qut vn chuyn khng kh, tc nhn sy i qua h thng, thc hin qu trnh sy. Qut t trc bung t qut y, cung cp khng kh vo bung t t nhin liu lm cht ti nhit ca calorifer.

Qut t trc calorifer qut y, c nhim v cung cp khng kh cho calorifer. Khng kh ngoi tri c qut y a vo calorifer, trao i nhit ri a vo thng sy, qua 1 on ng cong 900.

Qut t trc bung ha trn qut y, cung cp khng kh vo bung ha trn ha trn vi khi l sau bung t. Khng kh ngoi tri c qut y a vo bung ha trn lm gim nhit ca khi, qua 1 on ng cong 900.

Qut t cui h thng qut y, c nhim v ht tc nhn sy i qua thng sy cp nhit cho vt liu sy, sau y qua cyclon thu hi bi. ng ng t sau thng sy n ca vo cyclon c tit din hnh ch nht bng tit din ca vo ca cyclon, trn ng ng c mt on ng cong 90, r 6 nhnh i vo nhm 6 cyclon.

Lu lng kh ly theo bng 6. i vi 6 nhnh r trn ng ng trc cyclon th lu lng bng 1/6 lu lng nhnh chnh. Vn tc kh:V (m/s) vi Sng: din tch tit din ngang ca ng, m2

Chn qut ly tm p sut trung bnh U957, N05 c kch thc: (Trang 486-[6]) Mt bch ca ra: B2 = 350 mm. Mt bch ca vo: D = 509 mm.

Hnh 3.10: Kch thc qut ly tm

Ta chn ng ng vi cc thng s:

Bng 3.14: Bng thit k ng ng

STTon u ngon gia ngon cui ng

im bt uKch thc (mm)Kch thc (mm)Chiu di (m)Lu lng kh (m3/s)Vn tc kh (m/s)im kt thcKch thc (mm)

1Ca ra qut y 350 x 350 4000.51.25710Ca vo bung t 400

2Ca ra bung t 314 31420.77210Ca vo bung ha trn314

3Ca ra qut y 350 x 350 2240.50.93420Ca vo bung ha trn224

4Ca ra bung ha trn 334 3341.51.75120Ca vo calorifer 334

5Ca ra qut y 350 x 3507000.510.21726Ca vo calorifer 700

6Ca ra calorifer 700 700110.21726Ca vo thng sy 700

7Ca ra thng tho liu 672 x 208 672 x 2081.5(nhnh chnh)9.78270on ng r nhnh 1 672 x 208

672 x 208 672 x 2080.5 x 6(6 nhnh r)1.66712Ca vo cyclone 672 x 208

a. Tnh tr lc ma st trn ng ng:

Ch dng chy c xc nh:Trong :v (m/s):vn tc dng kh (m2/s): nht ngDt (m):ng knh tng ng ca ng. i vi ng trn:Dt = Dng i vi ng hnh ch nht:a, b (m) : chiu di 2 cnh ca tit din ng.Khi Re 4,000: dng kh ch chy xoy, xem dng chy khu vc nhn thy lc. T xc nh c h s tr lc ma st theo bng II.12/378[6].p sut cn thit khc phc tr lc ma st trong ng:

Bng 3.15: Kt qu tnh tr lc ma st trn ng ngSTTon ngL (m)Dt (m) 106 (m2/s)Re 10-5 (kg/m3)pms (mmH2O)

1Ca ra qut y n trc bung t0.50.415.732.540.0261.1770.195

2Ca ra bung t trc bung ha trn20.314188.211.670.1140.2640.977

3Ca ra qut y n trc bung ha trn0.50.22415.732.850.0261.1771.392

4Ca ra bung ha trn n trc calorifer1.50.33432.82.040.040.7482.739

5Ca ra qut y n trc calorifer0.50.715.7311.570.0261.1770.753

6Ca ra calorifer n ca vo thng sy10.717.9510.140.0281.0931.506

7Ca ra thng tho liu n cyclonNhnh chnh1.50.31816.28813.670.0271.15436.705

6 nhnh r30.31816.2882.340.0271.1542.157

Tr lc ma st ca trc ng chnh (dn khng kh)

Tr lc ma st ca trc ng dn khi:

b. Tnh tr lc cc b:p sut cn thit khc phc tr lc cc b trong ng dn:

(CT trang 95-[15])Trong : : H s tr lc

H s tr lc do t m:

(Ph lc 8/13-[1])f (m2):tit din ng nh.Hnh 3.11 t m

F (m2):tit din ng ln.

Bng 3.16: Kt qu tnh tr lc cc b ( t m)STTV tr tr lcng nhng m rngP1 (mmH2O)

Dt1 (m)f (m2)Dt2 (m)F (m2)

1T ca ra qut y n ng ng vo bung t0.350.11250.40.1260.0110.066

2T ca ra qut y n ng ng vo calorifer0.350.11250.70.3850.50120.317

Tr lc do t m trn ng ng chnh (ng dn kh):P1 = 20.317 (mmH2O)

Tr lc do t m trn ng ng dn khi:

H s tr lc do t thu:

V tr c tr lc do t thu l t ca ra qut y n ng ng vo bung ha trn. f: din tch tit din ng thu hp ( 0.0394 m2) F: din tch tit din ng ln ( 0.1125 m2)

Hnh 3.12: t thu

Tra v ni suy Ph lc 8/153-[1] ta c = 0.22

Suy ra:

H s tr lc ti on ng un cong 90:i vi ng tit din trn:Hnh 3.13: ng un cong tit din trn

Trong h thng c 3 ln un cong 900 trn ng trn l 2 ln t sau bung t n bung ha trn v 1 ln t bung ha trn n calorifer.

Chn t s = 0.3p sut cn thit khc phc tr lc cc b trn 2 on ng un cong t bung t n bung ha trn

p sut cn thit khc phc tr lc cc b trn on ng un cong t bung ha trn n calorifer:

i vi ng tit din ch nht:i vi ng tit din hnh ch nht, v tr un l sau thng sy, trc khi vo cyclon.H s tn tht ct p cc b ca dng chy ti ch un cong 90:CN = BVi l h s tn tht i vi ct tit din vungVi D = 0.208 (m)Ta chn t s R/D = 1 = 0.29L/D = 208/672 = 0.3 B = 2.108 CN = 0.292.108 = 0.611

Hnh 3.14:ng cong tit din ch nht

Suy ra: Tr lc do t thu trn dng ng chnh (ng dn kh)Vy P3 = P = 5.175(mmH2O)

Tr lc do t thu trn ng ng dn khi:

H s tr lc trn ng 7 ng: F1, F2, F3, F4, F5, F6, F7(m2): tit din ca ng tp trung v cc ng nhnh.v1, v2, v3 (m2): vn tc ca dng ng tp trung, ng thng, ng nhnh.Ta c F1 = F2 = F3 = F4 = F5 = F6 = F7

Chn gc phn nhnh = 45.H s tr lc trn ng nhnh: (Bng N22/392[6])H s tr lc trn ng thng: (Bng N23/393[6])Tn tht p sut trn cc ng ng nhnh :

Vy tn tht p sut do tr lc cc b trong ng ng chnh:

Tn tht cc b trn ng ng dn khi:

c. Tnh tr lc cho h thng trn ng ng chnh:

Tn tht ct p tnh trn ng ng chnh (ng dn kh):

Tn tht ct p tnh trn ng ng dn khi:

p sut ng ca kh thot ra trn ng ng dn chnh:

v: tc kh thot ra khi ng thi, v = 510,chn v = 8 m/s (trang 96-[15])

p sut kh ng ca khi thot ra khi calorifer:

Tn tht ct p tnh ton (ng chnh):

(CT trang 94-[15])

Tn tht ct p tnh ton (ng dn khi):

Tn tht ct p ton phn cho ng ng dn chnh:

(CT II.238a/463[6])Trong :t = 27.1C = 1.293 kg/m3: khi lng ring ca kh iu kin chun.k = 1.177 kg/m3: khi lng ring ca kh iu kin lm vic.B = 760mmHg : p sut ni t qut.

Tn tht ct p ton phn cho ng ng dn khi:

d. Tnh ton v chn qut:Nng sut ca qut V(m3/h): i v khng kh t bn th nng sut qut ly bng lu lng khng kh theo tnh ton iu kin lm vic.Tr lc m qut phi khc phc P (mmH2O): ly tn tht ct p ton phn iu kin lm vic.Cng sut ng c in khi vn chuyn khng kh nhit cao:

, (kW) (CT II.239b/464-[6])Trong :q: hiu sut qut ly theo c tuyn q: hiu sut truyn ng, khi truyn ng bng bnh ma st tr = 0.9Cng sut ng c in:Nc = k3N ,(kW) (CT II.240/464-[6])k3: h s d tr

Bng 3.17: bng tnh cng sut v chn qut trn trc ng chnhSTTi lngK hiuQut trc caloriferQut trc cylonCh thch

1Nng sut trung bnhV (m3/s)9.92810

2Khi lng ring trung bnh ca tc nhn (kg/m3)1.1351.124

3Tn tht ct p ton phnP (N/m2)20002000

4Hiu sut qutq0.610.61Tra th c tuyn qut ly tm 9-57,N05 (trang 489-[6])

5Cng sut trn trc ng c inN (kW)41.05340.95

6Cng sut ng c inNc (kW)43.7343.62Vi N>5 kW th k3=1.1 (bng II.48/464-[6])

Vy ta chn qut 9-57, N05 l hp l

Bng 3.18: bng tnh cng sut v chn qut trn ng ng dn khiSTTi lngK hiuQut trc bung tQut trc bung ha trnCh thch

1Nng sut trung bnhV (m3/s)1.2570.934

2Khi lng ring trung bnh ca tc nhn (kg/m3)0.720.963

3Tn tht ct p ton phnP (N/m2)262.462262.462

4Hiu sut qutq0.620.62Tra th c tuyn qut ly tm 9-57,N05 (trang 489-[6])

5Cng sut trn trc ng c inN (kW)0.4330.423

6Cng sut ng c inNc (kW)0.650.635Vi N