Unit Operations. Chemical Engineering SeriesFull description
Description complète
che
DryingFull description
Drying
hhhhhhhoooooDeskripsi lengkap
Kiln Drying
Sawdust with EthanolFull description
Prelab1 che 136
DryingFull description
otk 2Full description
drug manufacturing notes on drying procedure. UST 3rd year BS Pharma.
all about solar dryingFull description
makalah pdtk driyingFull description
alat drying
ass Transfer 2 M ass
CPB 20103
CPB20103MA MASSTRANSFER 2 TUTORI AL2 DRYI NG OPERATI ONS 1.A . Ai rof20oC andIbarwi t hr el at i vehumi di t yof80% i sheat edt o50oC.The heat ed ai rflowsal onga flatt r ayfil l ed wi t h comp mpl et el ywet t ed mat er i al . 2 The heat t r ansf e r coe ffic i ent i s 35 W/m . K and t he l at ent heat of 6 v apor i z at i oni s2. 45x10 J/kg .Ca l c ul a t et hec o ns t a ntdr y i ngr a t e . 4 [ R =3. 43x10 kg/m2. s] 2.Awetsol i dwi t hamo moi st ur econt entof0. 50kgH2O/kgdrysol i doccupi es 2 0. 1 m on a flatt r ay .A l abor at ory experi mentshows ws t hatt he cr i t i cal mo i s t ur ec o nt e nti s0. 2kgH2O/kgdrysol i dandt heconst antdryi ngr at e 2 i s 0. 36 g/m . s.Cal cul at et he t i me r equi r ed t or educe t he moi st ur e c o nt e nto ft hewe ts o l i do nt het r a yc o nt a i ni ng2kgofdr ys o l i df r o m 0. 40 t o0. 20kgH2O/kgdrys ol i d. [ 3. 09hr ] 3.A . A por ous s ol i d i s dr i e d i n a bat c h dry e r under cons t ant dr yi ng condi t i ons.5hour sarer equi r edt oreducet hemo moi st ur econt entf r om 35 t o10per cent .Thecri t i calmoi st ur econt entwasf oundt obe20per cent andt heequi l i bri um moi st ur e4per cent .Al lmoi st ur econt ent sareont he dr ybas i s .As s umi ngt hatt her a t eofdr y i ngdur i ngt hef al l i ng r at epe r i o d i spr o po r t i o nalt ot hef r e e mo i s t ur ec o nt e nt ,c al c ul at et het i mer e q ui r e d t odryasamp mpl eoft hesame mesol i df r om 35 t o5 per ce ntundert hesame me dr y i ngc o ndi t i o ns . [ t=9. 67hr] 4.A .A gr anul ar sol i d i s t o be dr i e d i n a t unnel dr y er f r om 4 50% t o 10% moi s t ur e underi dent i calcondi t i ons i n 3. 0 x 10 s.The cr i t i calandequi l i bri um moi st ur econt ent sar e12% and3%,r espect i vel y . Cal cul at et het i mere qui r ed t o dryt hesol i df r om 50% moi st ur et o 5% mo i s t ur ei fa l lmo i s t ur ec o nt e nt squo t e dar eo nadr yba s i s . [ t=7. 37hr] 5.A gr anul ari nsol ubl esol i d mat er i alwetwi t h wat eri sbei ngdri ed i nt he const antr at eper i odi napan0. 61m x0. 61m andt hedept hofmat er i al i s25. 4mm.Thesi desandbot t om ar ei nsul at ed.Ai rflowsper pendi cul ar t ot he t op sur f ace at a v el oc i t y of3. 05 m/s and has a dry bul b o o t emp mper at ur e of60C and we t bul bt emper at ur e of29. 4C.The pan
FG/T2/July2011
M ass Transfer 2
CPB 20103
cont ai ns11. 34kgofdrysol i dhavi ngaf r eemoi st ur econt entof0. 35kg H2O/kg drysol i d and t hemat er i ali st o bedr i ed i nt heconst antr at e per i od t o 0. 22 kgH2O/kg drysol i d.Cal cul at et hedry i ngr at eand t he t i mei nhour snee ded. [ R =1. 642kg/h. m 2,t=2. 41h]
6.A sl ab wi t h awetwei ghtof5 kg or i gi nal l ycont ai ns50% moi st ur e( we t basi s) .Thesl abi s600by900by75mm t hi c k.Theequi l i br i um moi s t ur e o cont enti s5% oft het ot alwei ghtwhen i n cont actwi t h ai rof20C and 20% humi di t y .Thedryi ngr at ei sgi veni n Tabl e1 f orcont actwi t h ai rof t heabo v equal i t yatade fini t ev e l o c i t y .Dr y i ngi sf r o mo nef ac e .De t e r mi ne t het i mer e q ui r e dt odr yt hes l a bt o10% mo i s t ur ec o nt e nt( we tba s i s ) . Tabl e1 Wet–sl abwei ght ,kg 9. 1 7. 2 5. 3 4. 2 3. 3 2. 9 2. 7
Dr yi ngr at e,kg/m 2. h 4. 9 4. 9 4. 4 3. 9 3. 4 2. 0 1. 0
7.A wetfil t ercakei n apan 1f tx1 f tsquar eand1i ncht hi cki sdr i edon o t het op sur f acewi t h ai ratwetbul bt emper at ur eof80Fand adrybul b o of120F flo wi ngpar a l l e lt ot hes ur f ac eatav e l o c i t yo f2. 5f t /s .Thedr y 3 densi t yoft hecakei s150l bm/f t andt hec r i t i c alf r e emo i s t ur ec o nt e nti s 0. 09l bH2O/l bdr ys o l i d.Ho wl o ngwi l li tt ak et odr yt hema t e r i a lf r o ma f r e emo i s t ur ec o nt e nto f0. 20l bH2O/l bdr ys o l dt ot hec r i t i c a lmo i s t ur e c o nt e nt ? [ t=17. 03h] 8.Sl absoffil t ercakewi t habonedrydensi t yof1600kg/m3 ar et obedr i e d f r om an i ni t i alf r eemoi st ur e cont entof90% ( drybasi s)t o a finalf r ee moi st ur econt entof5% ( drybasi s)bat chwi sei nt r ayst hatar e1 m l ong by0. 5m wi dewi t hadept hof3cm.Dr yi ngwi l lt akepl aceonl yf r om t he o o t op sur f ace.Thedryi ngai rcondi t i onsar e1 at m,60C and a 39C we t bul bt emper at ur e.Ai rflowsper pendi cul art ot het opsur f aceatv el oci t yof 3. 5m/s.Exper i ment sundert hesedryi ngcondi t i onsshow acr i t i calf r ee moi st ur econt entof45% ( drybasi s)wi t hassumi ngt hatt hedryi ngrat ei s al i ne a rwi t hf r e emo i s t ur ec o nt e ntt hr o ug ho r i g i n.De t e r mi ne :
FG/T2/July2011
M ass Transfer 2
CPB 20103
a) b)
Thedr yi ngt i mef ort hec ons t antr at eper i odi nhour s. Thedr yi ngt i mef ort hef al l i ngr at eper i odi nhour s.
9.A we tso l i di st obedr i edi n apan 0. 61 m by0. 61 m and t hedept h of mat er i ali s25. 4 mm underconst antr at eper i od.Thesi desand bot t om ar ei ns ul at e d.Ai rflo wspar a l l e lt ot het o ps ur f ac eatav e l o ci t yo f3. 05 o m/sandhasadrybul bt emper at ur eof60 C andwe tbul bt emper at ur e o of29. 4 C.Thepan cont ai ns11. 34 kg ofdrysol i d havi nga moi st ur e c o nt e nto f40% a ndt hema t e r i a li st obedr i e di nt hec o ns t antr a t epe r i o d t ot hecr i t i calmoi st ur econt entof20%.Theequi l i br i um moi st ur e was f oundt obe4%.Al lmoi st ur econt ent sareont hedrybasi s. a) Cal cul at et hedr yi ngr at eandt het i mer equi r edi nhour s. 2 [ R =1. 599kg/h. m ,t=3. 82hr ] b)
Cal cul at et he dr yi ng r at e and t he t i me needed i n hour si ft he dept hofmat er i ali sr educedt o12. 7mm. [ R =1. 599kg/h. m 2,t=1. 91hr ]
10. A we ts o l i di sdr i e dwi t ha i ra t6 0oC andahumi di t yof0. 010kgH2O/kg dr ya i r .Thea i rflo wspa r a l l e lt ot hefla t ,we ts ur f a c eo ft hes o l i da ta v el oci t yof5m/s.Undert hesecondi t i onst heheatt r ansf ercoeffic i enti s 0 . 8 ρ v ) ,whe gi v en by h = 14. 3( r e ρ i st hede ns i t yo ft hemi s ta i ri n kg mo i s ta i rp e runi tv o l umemo i s ta i r .Thes ur f a c ea r e aa v a i l a bl ef o rhe a t 2 exchangewi t hai ri s0. 25m andt hel a t e nthe a to fv a po r i z a t i o ni s2. 45x 6 10 J/kg .Ca l c ul a t et het o t a la mo unto fwa t e re v a po r a t i ngpe runi tt i me . 4 [ R =1. 71x10 kg/s]
