NLN •132-11/2016 "15 ^MO HiNH TOAN HOC MO TA QUA TRJNH NHIET PHAN THAN GUI G Mathematical Model of wood charcoal pyroiysis process ThS Dgng The Hung''; TS Ding Tran Thg^; PGS.TS Pham Hoang Lirong' '- DH Slf Phgm Ky thuit Vinh; ^^- DH Bich khoa Hi Ndi Bii tiio trinh biy kit aui nghien ciru xay dyng md hinh toan hoc md ta qua trinh nhigt phan than cu/ go Cic yiu to anh hirang cua qui trinh nhtr thdng so nhiet vat ly, eiu tnJc cua v$tligu, mdi tnrdng nhigt phin, giin nhiet phan da dirge ke den Chit lirgng sin pham cua qui trinh nhigt phan than cui go phy thugc rat ldn vao cac btong so inh hirdng niy Vi vgy, viec xic dfnh dwgfc moi quan hg toin hgc niy cd ich rat Idn cho viec nghien cu-u, tinh tinh toin va vgn hinh cic thiet bj nhigt phan de thu dirgv than ciJi cd chat Itrgng tot Tir khda: Nhifit phdn than cui gd, Nhifit phan go, Md hinh nhifit phdn Bang Ky hieu va y nghia cac dai Iwgng C4c d^i tirqng TIKI qlw/m'] Q[W] p[kg/m^ MW/mK] R[J/mol K) Als'l y nghia Nh>$t dO M d$ dfing nhi$t D nhiat K li/ong neng H s6 d^n nhifit H s6 khi, 8314 hs6m0 2-5>c khdng cd hifin tupng eo rtit cua than so vdi g i ban diu sau nhifit phdn (3) Dfic tinh nhifit thay dii theo ty trpng nhung dupc tinh trung binh so vdi nhifit dfi vd dupc eho bdi phuang trinh 1.1 Trong suit qud trlnh nhifit phdn, vdi mfi hlnh dfing hpc tic dp hu-u hgn khii lupng rieng g l rdn vimg nhifit phdn thay d i i lidn U^c tir khii lupng rifing ban diu eua khli g i p„ din khli lupng ridng cijii cimg eua charcoal Pf Vi vfiy, tgi bat ky thdi dilm ndo mfit phdn t i tgi viing nhifit phan cd the eoi Id hin hp-p cua ca than hinh thdnh va g i chua nhifit phdn Vdi gia thilt khdng cd sy CO ngdt cua than, tit ca khii lypng ridng diu dya tren thi tich ban diu cua khli g i rdn Ta cd khii lupng ridng tire thdi ps cua khli g i dupc tlnh theo cdng thirc (2.1): pSx,f) = pA^.l) + p,ixj), Pf Trong (56: ;- = ^^, la ty 1$ san li/o'ng than viii P luo'ng g5 ban Sku Oo iigii>'^i bill Cllucoal •a , - ^ ^ - ^ - > ^ •A ^ /•\S ^ i I ITloilg tUQng lit "* Nluet lot, mil ^ ^ i*r (2.1) Trong 66: p, vi p^ An \u : , V ^ = V(/lV7•)fe(7•), (1-y) I kp^(^,t)c^(T{4,t)-T,)ti^.riT dd (2.3) Trong 06, QiT) = [(C -yC, - (I - r)C^)(T - r j - &i,]kp„ khdng cd sy hinh thdnh cdc chit d l bay tiai ngodi Ax vd ty Ifi ndy trd thdnh: ia ngu6n nhi^t sinh vi Aioia iu'O'ng nhi$t cdn thilt Q-r) \kp„(xJ)C^(Tixj)-T,)dx cung d p cho qua trinh nhi$t phan d^ phdn iy mOt doTi vj khii iuvng g5 ran, a nhi#t 66 To Trong Cdc xdc nhfin ttrang irng vdi md hlnh nhifit phdn phirorng trinh (2.3) hi s6 dSn nhi$t A cua khii ran ia tnrdc id: ting h(?p tuyin tinh cua h$ s i din nhi^t phSn g i chira nhi$t phan va charcoal, dwyc xac djnh theo />.(!-/) J S(.i-4(.t))^C^(.m,l)-T,)di phirong trinh (2.4) [4] (2.4) P« Pf Vdi din nhifit mfit chilu, cdc trudng hpp khii g i cd d u tgo Id phiin, khii tn.i hay khii d u phuang trinh (2.3) Arpc thu gpn 1^ nhu phuang trinh (2.5) sau (AC+p.C.)^+C>:.^ = l|-(xu5)+(?(r) et "^ dx X ax Ox (2.5) Trong dd n Id thdng s i hlnh dgng cua khii g i Vdi phiin g i , n = frg g i n =1 vd khoi d u g i n = 2- Ding thdi, thdng lupng khdi luvng ctJa chit tlic cho todn bfi qud trinh dupc xdc djnh tiieo phuang trinh Ma rfing si/ thing nhit tr4n toan bfi miin khfing gian va su dyng tlnh chit cua ham delta [6], ty i# naytrdthanh: p,(l-r)CJM)-T„) '^AO „.„ Biiu dl thirc biiu thj sy phg thufic vao thfifi gian cua nhi^t dfi nhi^t phan Tp, diiu nSy khfing Ihvc sv c i n thiit va h&u ich Nhu' v^y, ting ho'p qua toSn bfi th« gian cua qua trlnh than hfia, tim thiy nhi^t dfi nhifit phan t i l iru cho qua trlnh nhi$t phan nhi/ sau: T^=\]nx,l)kp„dxdl (2.7) ^ 2.4 Khao sat s y anh hu^ng cua cac t h i n g sfi vat ly 'I AO iiUm Qrtrifng 'Zfc,; A „ , 'Bat4* Um« 3K.> W d / 18'NLN-132'11/2016 2.4.1 Anh huong cua hinh dgng go Chdnh Ifich khii lupng g i trudc vd sau qiJd trlnh nhtfit phdn cung ehinh la lupng chit bic thodt ttr khii g i , dupc md ta qua phuang trinh 2.6 0" cung mpt nhifit dp nhifit phan, sy thay ddi ndy phg thufic vao hinh dang ciJa go Vdi cdc gia trj n = 1, la hfi s i tuang irng vdi ciu tgo ciJa khii gd : Thanh gd, tn^ gd va khoi g i hinh d u Phuang trinh 2.6 dupc cu thd theo hinh dgng khdi go va tic dfi thay doi khdi lupng 6iFiyc md ta d cdc hinh: hinh 3; hinh vd hinh dudi ddy 2.4.2 Anh hirdng cua khoi lirgng rieng go din nhigt dg nhigt phan A Mo hiuh abet pbw loc pbin li laoi bfD - B1 Mo liuifa oia^phau\ -1 V ' Jl \ Hinh T6c dp thay doi khoi iu^g m,(x,l) = y:= go TrhP.+Pjx'dx P -L i Hlnh T6c Og thay doi khoi Iwgng go /»l(i,t) = Y = —!— \{p^ + p^)dx " • A Mo liiiili ulii^ pbau toe dp phan b aoi han hiidi iiluet phan \'oi toe pbiii b Idious 100) han Ci'ia Antamis [1] k Mo - - BBl A 35 Tir phu'ong trinh 2.7, ta c6 du-iyc thi hlnh mfi ta 81/ anh hu'o'ng cua khoi Iu'O'ng rifing g i din nhi^t dfi dfi nhi^t phan Khii iiro'ng rifing cua gS ifi'n hen se iam tang tai nhifit, giam ty Ifi dit nOng diiu nSy din din sir giam nhifit dfi nhifit phan va kit qua la qua trinh nhifit phan dien chjm hon TCr d i thj mfi ta, Tp giam tif 646,8 K din 628,8 K khii luvng rifing p„ cua g i giam tir 400kg / m' din 800kg / m' :i 30 •h > IS j 10 05 00 ]\ ' 150 200 250 Tlioiaan {s) Hlnh Toe dp thay doi khoi lu^g ml(x,t) = }• = P,l- 300 trit go f(p + p )xdx : Hinh 6, Anh huxmg cua khoi It/qmg rieng cua go ti/i nhl^t di nhiit phin I 'Jriiiliui 1>tii lint 'liiirii Uitm *".« 'J^-.' NLN* 132-11/2016'19 cimg khli luong Trong dd, tic dd phdn ly Igi giam ddn ttiay d i i hinh dgng cua khii g i theo thif tu tir khii d u , khii trg din g l , Vdi sy thay dii ndng suit than dinh tn/dc theo md Gd cang dfic, tire khii lupng rifing cua g i cdng hinh nhtfit phdn tie dfi tdi hgn, tuang ung rnfit sy Idn se Idm tdng tai nhiet, dteu din tdi sy giam thay dii lupng than tgo ra, dieu ndy lam thay ddi nhifit nhifit dd nhifit phdn va keo theo sy tdng thdi gian dfi nhifit phdn Hinh md ta sy phg thufic ndy Anh huoDg cua su thay dii ndng suit than din ten nhiet phan Slf thay dfii nhifit phdn eung tgo ndn sy bien thay ddi tic dfi dit ndng Nhifit dp nhifit phdn thay ddi tir 632K - 637K trdn dai ndng suit than 7,4 % - d i i khii lupng than hinh thdnh, cy t h i : Khii lupng ridng cua than hinh thdnh se tdng len tdng 59.2 %, tuang img vdi khii lupng rieng than nhiet dp nhiet phan va ngupe Igi phdm 50 kg/m^ - 400 kg/m^ 2.4.3 Anh bircng cua Tp den khoi Iwgng rieng cua than tao Khn kmia « f en SiMi (kym^l Hlnh Anh hu^g khil lugng than tdi nhl^t dg nhi^tphin K^T QUA VA T H A O L U A N Kit qua nghifin cuu cho thiy: cung nhifit dfi nhifit phdn, hlnh dgng g i anh hudng den tie dfi phdn li vd thdi gian nhifit phdn g i , cg thi: Vdi khoi g i ed dgng chG" nhfit, thdi gian nhifit phdn diln nhanh han so vdi trg g i trdn, nhung Igi chfim han so vdi khii d u d K t T LUAN Qud trinh nhiet phan chit rdn md diln hinh Id gd la qud trinh phifc tgp Id t i hpp cac biln d i i hda hpc vfit ly vd nhifit hpc Vific xdc djnh tie dp than hda nhifit dp nhifit phan cua qud trinh, tgo dieu kifin ddnh gia chit lupng, san lupng cua than sau nhifit phdn Trong khudn de tai, nhdm tdc gta da vgn dgng kit qua cua cdc nhd khoa hpc di trudc vific thira nhfin cde qua trinh hda hpc xdy nhifit phdn ehlt rdn sinh hpe ndi chung, cg t h i hda eho g l ndi rifing Tir dd tim mii lifin hfi cdc thdng s i vfit ly diln qud trinh nhifit phdn thdng qua vific xde djnh nhifit dp nhifit phdn, ding thdi ddnh gid, so sdnh vdi mdt s i kit qua dd cdng b l o l dam bao kit qua t i t nhit, cln chi tilt hda sy anh hudng cua tat ca cde yiu t i n|f tgi nhu true vat lifiu, ede dfic tlnh cua vfit lifiu cOng nhu sy anh hydng ciia cdc yiu t i bdn ngodi nhu nhifit dfi mdi trudng, nhifit Iupng cung cip, sy thit thodt nhifit mdi trudng qud trinh nhifit phdn Cdc yeu t i se dupc d l cfip ede nghidn ciru tllp theo ABSTRACT 7?j»s attKle present the results ofreseansh using maUis modelling to describe the pyroiysis of charc fecfcre affectingtfiispyro/ys/s process include the physKal parameters of pyroiysis the structure of mater envkonment and the c^art of pyroiysis The process of wood pyroiysis in making charcoal depends on thes physical parameters Therefore, a successful modelling of wood pyn^s in making charcoal can assist in these thermal physk:al parameters to produce charcoal of good qualityKey vi/ord: Pyroiysis, Charcoal, Wood charcoal pyroiysis, Pyroiysis model TAI LI$U THAM KHAO [1], Arrtwnius Atreya, A (1983) Pyroiysis ignition and fire spread on horizontal surfaces of wood Camtiridge MA Harvard Unrversity [2] Atreya, A & Baum H R (2002) A model of opposed-flow flame spread over charrir>g matenals, Sapporo, Japan, Combustion Instilirte [3] A t a y a , A Wooldndge M & Schwank, J (2003) 'Development of a Uierettcal model to enable design and control of a biomass harvester for field use Vnal thennoctiemically converts biomass to liquid bio-fuel for H^ production' Preapplication for DOE program [4) Baum, H.R & Alreya, A (2005) Transport of Gases in Chamng Sdlids Joint Meeting of U S Section Combustion Institute Phaadelphia.PA.USA [5] Baum H R & Atreya, A (2007) 'A model of transport of fuel gases in a chamng sdid and its application to opposed-Row ftame spread" Proceedings of the Combustion Insttute 31 (2) 2633-2641 [6) GS TSKH Ding OuAc Ptiu PGS TS Ptiam Lft n (2002) C a s e ky thujt nhj^t nhS xuSt b i n gido dye Phan bien: GS TSKH Nguyin ST Mdo II 60 nam 'Jriirliig ^Oui U-te 'Bati, Ulintt JCa c khdng cd hifin tupng eo rtit cua than so vdi g i ban diu sau nhifit phdn (3) Dfic tinh nhifit thay