Online In eg a ed F ac iona ion-Hyd olysis o Lignocellulosic
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Biomass using Sub- and Supe c i ical Wa e
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C is ian M. Pique as1, Ál a o Cabeza2, Gianluca Gallina2, Danilo A. Can e o2, Juan
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Ga cía-Se na2* and Ma ía J. Coce o2
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1Plan a Pilo o de Ingenie ía Química, PLAPIQUI-Uni e sidad Nacional del Su -
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CONICET, Camino La Ca indanga km 7-CC 717, (8000) Bahía Blanca, A gen ina.
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Phone: +542914861700 / Fax:+542914871600
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2High P essu e P ocesses G oup, Depa men o Chemical Enginee ing and
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En i onmen al Technology, Uni e si y o Valladolid, Escuela de Ingenie ías
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Indus iales, (47011) Valladolid, Spain. Phone: +34 983184934
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*e-mail add ess: jg[email p o ec ed]
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Keywo ds: Glucose, Glycolaldehyde, Kine ics, P ocess De elopmen , Xylose, Holm
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Oak Wood
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Abs ac
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A no el p ocess coupling he ac iona ion and hyd olysis eac o s is p esen ed. Holm oak was
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used as eal lignocellulosic biomass o be ea ed. In he ac iona ion eac o , hemicellulose and
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cellulose we e solubilized and pa ially hyd olyzed in di e en s ages wi h he aim o eeding
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he hyd olysis eac o wi h high C5 concen a ions o C6 concen a ions. The ac iona ion was
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pe o med in wo s ages: a 180ºC op imizing he hemicellulose ex ac ion and a 260ºC
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ex ac ing cellulose and ha d hemicellulose emaining in he biomass s uc u e. Th ee wa e
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lows we e es ed: 11, 17 and 26 cm3/min. Suga yields om 71 o 75% we e eached, mainly
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composed o xylose and glucose oligome s and lowe amoun s o o he chemicals, like e o-
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aldol p oduc s, ace ic acid o 5-HMF. The ou le s eam om he ac iona ion eac o was
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di ec ly mixed wi h sub o supe c i ical wa e a he inle mixe o a SHR whe e he eac ion
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ime was p ecisely con olled. The empe a u e, p essu e and eac ion ime we e modi ied o ge
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an insigh o hei e ec on he yield o e o-aldol condensa ion p oduc s. Yields o 24% o
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glycolaldehyde, and py u aldehyde we e ound a 8.3 s, 350ºC and 162 ba (hyd olysis eac o
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condi ions). In o he hand, 25% o lac ic acid was ound a 0.23 s, 396ºC and 245 ba . A
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discussion based on a known eac ion pa hway is p oposed. Mo eo e , a kine ic model o he
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hyd olysis eac o was p oposed, being able o ep oduce he expe imen al da a wi h de ia ions
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lowe han 10 % o suga s and o he p oduc s ex ac ed. This combined p ocess pe o ms a
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selec i e alo iza ion o eal lignocellulosic biomass, a oiding he cos ly p ocess o ex eme
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g inding needed o he luidiza ion in a con inuous hyd o he mal p ocess.
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In oduc ion
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E en i i is easonably assumed ha biomass om plan s will be he main ca bon sou ce in he
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u u e, he choice o which eac ion medium should be used o depolyme ize and alo ize
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biomass has no been aken ye . P essu ized luids, especially sub and supe c i ical wa e
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(Tc=374ºC and Pc= 221 ba ), can be poin ed as a p omising al e na i e o depolyme ize and
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alo ize biomass [1-5]. Physical and chemical p ope ies o wa e can be modi ied by adjus ing
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p essu e and empe a u e a ound he c i ical poin , making wa e a eac ion medium able o
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a o di e en kind o eac ions [1]. Because o his eason, ho p essu ized wa e has been used
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as eac ion medium o ac iona ion [6-9] , hyd olysis [10-12] and alo iza ion o biomass [13-
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16].
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The composi ion o lignocellulosic biomass is highly dependen on he plan species and
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g ow h condi ions. Howe e , i can be conside ed ha he a e age composi ion o
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lignocellulosic biomass is app oxima ely: cellulose (40% w .), hemicellulose (25% w .), lignin
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(25% w .), ex ac i es and ashes (10% w .) [17]. Al hough biomass is composed by di e se and
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complex molecules, i can be ac iona ed p incipally in o C6 suga s (mainly glucose), C5
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suga s (mainly xylose) and lignin [3]. These h ee ac ions can be u he modi ied o p oduce a
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wide ange o p oduc s like: e hanol, hyd ogen, glycolaldehyde, py u aldehyde, lac ic acid and
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5-HMF among o he s [3, 18-25].
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The ac iona ion o biomass can be de ined as he selec i e sepa a ion o C5 suga s, C6 suga s
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and lignin om he o iginal biomass ma ix. This p ocess was s udied unde hyd o he mal
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condi ions in di e en ways o ope a ion: ba ch, semi ba ch and con inuous [3, 26]. Semi ba ch
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and con inuous p ocesses allow ob aining highe yields o suga s and chemical compounds han
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ba ch eac o s, because i is possible o con ol he empe a u e (T) and he esidence ime ( )
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mo e accu a ely han in ba ch p ocesses [27]. Con inuous p ocesses a e he mos app op ia e o
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con ol he eac ion condi ions (T and ), howe e , in mos cases i is necessa y o apply
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expensi e p e ea men s o he aw ma e ial be o e he ac iona ion+hyd olysis p ocess, o
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example: exhaus i e size educ ion [28]. On he o he hand, he con inuous p ocess can be
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pe o med a di e en ope a ing condi ions in o de o sepa a e he C5 suga s om he C6
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suga s.
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The ex ac ion o hemicellulose om woody biomass can be ca ied ou a empe a u es
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be ween 130ºC and 260ºC, solid eac ion imes be ween 20 and 60 min and liquid esidence
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imes inside he eac o be ween 0.1 min and 1 min. A hose condi ions, hemicellulose can be
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bo h ex ac ed and hyd olyzed [29, 30]. A e he ex ac ion a 180ºC, wo p oduc s a e usually
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ob ained: a liquid composed mainly o C5 suga s and a solid composed o C6 suga s and lignin.
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These wo p oduc s can be sepa a ed by il a ion. Then, he cellulose in he solid can be
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hyd olyzed a supe c i ical condi ions o ob ain a wa e solu ion o C6 suga s and a solid
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en iched in lignin. These p ocesses can be ca ied ou in wo eac o s wi h a il a ion ope a ion
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be ween hem. Ano he op ion which allows he in ensi ica ion o he p ocess is using one ixed
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bed eac o . In such a case, he biomass is loaded in he eac o and he hyd olysis empe a u e
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is changed in o de o hyd olyze C5 o C6 suga s [31]. The semi ba ch p ocess allows high
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pe o mances on he yields o C5 suga s hyd olysis. Howe e , when he eac ion empe a u e is
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inc eased o hyd olyze he ecalci an cellulose and hemicellulose, he yield o eco e ed suga s
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dec eases because o he inc emen o he suga s u he eac ions [10, 11, 32].
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The con inuous eac o s ha e been employed in many applica ions o he alo iza ion o suga
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s eams allowing a p ecise con ol o e he eac ions [19-21]. These eac ions can be managed
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using p essu ized wa e and choosing he adequa e eac ion condi ions. Fo example, a
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empe a u es be ween 200ºC and 300ºC (250 ba ) he wa e molecules a e highly dissocia ed
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a o ing he ionic eac ions, like he p oduc ion o 5-HMF om uc ose and glucose [1]. On he
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o he hand, a 400ºC (250 ba ) he wa e molecules a e highly associa ed a o ing he non-ionic
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eac ions, like he e o aldol condensa ion eac ions [1].
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In his a icle, a no el in eg a ed ac iona ion- alo iza ion p ocess was designed and buil using
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wooden biomass as aw ma e ial and wa e (subc i ical and supe c i ical) as eac ion medium.
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The wooden biomass was ac iona ed in a ixed bed eac o a di e en empe a u es. The
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solubilized p oduc s we e di ec ly injec ed o a con inuous nea c i ical wa e eac o o
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e icien ly con e C5 and C6 suga s in o aluable p oduc s, like glycolaldehyde,
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py u aldehyde and lac ic acid a oiding a u he hyd olysis o o ganic acids. In addi ion, a
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kine ic analysis o he biomass hyd olysis was done in o de o s udy he di e ences in he
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p ocess when subc i ical and supe c i ical condi ions we e used.
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The objec i e o his esea ch pape was o design a no el p ocess capable o con e ing
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lignocellulosic biomass in o aluable p oduc s eluding he excessi e milling o biomass and
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dec easing he numbe o eac o s.
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1. Expe imen al
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2.1 Ma e ials
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Deionized wa e p oduced by Elix® Ad an age pu i ica ion sys em was used as eac ion
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medium o un he expe imen s. The s anda ds used in a High Pe o mance Liquid
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Ch oma og aphy (HPLC) analysis we e: cellobiose (≥98%), glucose (≥99%), xylose (≥99%),
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galac ose (≥99%), mannose (≥99%), a abinose (≥99%), glyce aldehyde (≥95%), glycolaldehyde
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dime (≥99%), lac ic acid (≥85%), o mic acid (≥98%), ace ic acid (≥99%), ac ylic acid (≥99%),
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u u al (99%) and 5-hyd oxyme hyl u u al (≥99%) pu chased om Sigma. 0.01 N solu ion o
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sul u ic acid (HPLC g ade) in Milli-Q® g ade wa e was used as he mobile phase in he HPLC
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analysis. Sul u ic acid (≥96%) and calcium ca bona e (≥99%) supplied by Pan eac, Spain, we e
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used as eagen s o he quan i ica ion p ocedu e o s uc u al ca bohyd a es and lignin [33].
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Also, Milli-Q® wa e was used in his de e mina ion. Holm oak wood employed as aw ma e ial
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was collec ed in Spanish o es s. The wood was milled ob aining chips wi h a e age wid h o 2
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mm and a e age leng h o 5 mm, as i is shown in Figu e S1 o Supplemen a y Ma e ial.
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2.2 Analy ical me hods
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The composi ion o he holm oak wood aw ma e ial, exhaus ed solid and ex ac ed liquo was
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de e mined h ough wo Labo a o y Analy ical P ocedu es (LAP) om NREL [33, 34]. The
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p ocedu e o solid samples consis s in quan i ying he s uc u al ca bohyd a es and lignin in he
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biomass as ollows. A) The biomass was weigh ed be o e and a e being d ied in an ai d i en
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o en a 105 °C o 24 hou s in o de o calcula e he mois u e con en . B) D ied biomass was
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ea ed in a Soxhle equipmen wi h n-hexane, lea ing a solid ee o oils and o he ex ac i es.
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C) 300 mg o d ied and ee-ex ac i es solid om s ep (b) we e hyd olyzed in 3 ml o 72% w
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sul u ic acid solu ion a 30 °C o 30 min, in o de o b eak he bonds be ween biopolyme s and
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he main solid s uc u e. D) The mix u e o oligome s ob ained in s ep (c) is dilu ed using 84 ml
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o deionized wa e and hea ed a 120 °C o 60 min wi h he aim o hyd olyzing hemicellulose
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and cellulose o ob ain hei co esponden monome s [35]. E) The solid is sepa a ed om he
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solu ion by acuum il a ion. F) The o al mass o solubilized suga s was quan i ied as he
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di e ence in weigh be ween he o iginal solid and he exhaus ed solid a e o en d ying a 105
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°C in o en o 24 hou s. G) The exhaus ed solid is placed in a mu le a 550 °C o 24 h and he
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emaining esidue was weigh ed be o e and a e his s ep o calcula e he insoluble lignin and
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he ash con en o he sample. H) A liquid aliquo was analyzed wi h UV-Vis spec opho ome e
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a 320 nm wi h ex inc ion coe icien o 34 Lg−1cm−1 [36] o calcula e he amoun o soluble
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lignin. I) Ano he liquid aliquo was neu alized o pH ange 6 o 7, hen i was il e ed using a
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0.2 µm memb ane and analyzed by HPLC de e mining he ca bohyd a es composi ion. This
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p ocedu e is pe o med using a column SUGAR SH-1011 (Shodex) wi h a 0.01 N o sul u ic
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acid solu ion as a mobile phase. To iden i y he soluble p oduc s, wo de ec o s we e used:
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Wa e s IR de ec o 2414 (210 nm) and Wa e s dual λ abso bance de ec o 2487 (254 nm). In
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o de o calcula e he amoun o ca bohyd a es, each ch oma og am was in eg a ed nume ically
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by decomposing i in o a sum o 9 o 13 Gaussian peaks, minimizing chi squa ed unc ion o a
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Le enbe g-Ma qua d -Fleche algo i hm [37]. Glycolaldehyde and Py u aldehyde esul ed o be
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o e lapped, since he e en ion ime o hei s anda ds is ex emely close (11.99 s 12.24
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minu es, espec i ely). So we e e o hem as glycolaldehyde-py u aldehyde.
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The aw ma e ial con ained 1.6 % w . ex ac i es, 1.8% w . mois u e, 0.2% w . ashes, 24.2% w .
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Klason lignin ( om which 4.0% co esponds o soluble lignin), 45.7% w . o hexoses, 23.9%
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w . pen oses. The sum o all he componen s ep esen s he 97.4% o o al weigh , he
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disc epancy is due o expe imen al e o s like he loss o solid ma e ial a e he eco e y a he
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end o he expe imen s, o he inhomogenei y o he ma e ial which can ha e sligh ly di e en
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composi ions depending on he analyzed aliquo ; in any case, i is inside he accep able
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expe imen al e o .
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The amoun o C6 was calcula ed as he sum o glucose, cellobiose and uc ose concen a ions.
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Xylose was he only C5 de ec ed. Ace ic acid was conside ed o come om he deace yla ion o
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xylan du ing he ex ac ion p ocess o , as explained in he nex sec ions, om he hyd olysis o
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py u aldehyde. The hyd olysis p oduc s om hexoses and pen oses we e mainly
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glyce aldehyde, glycolaldehyde, py u aldehyde, lac ic acid, 5-hyd oxyme hyl u u al and in
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some cases ac ylic acid we e de ec ed in e y low concen a ion.
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The p ocedu e ollowed o analyze liquid samples consis s in he s eps (C), (D) and (I)
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desc ibed abo e. In his case, he ca bon con en liquid solu ions was de e mined by o al
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o ganic ca bon (TOC) analysis using a Shimadzu TOC-VCSH equipmen . E e y sample was
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p e iously il e ed using a 0.2 µm sy inge il e and dilu ed 1:10 imes wi h Millipo e wa e .
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The pH o he ou le s eam was measu ed online using an elec onic pH-me e (Nahi a model
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903).
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2.3 Expe imen al se up and ope a ion p ocedu e
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The se up used in his wo k is shown in Figu e 1. The sys em consis ed in wo eac o s online
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in eg a ed: 1) he ac iona ion eac o (R.1), whe e he C5 and C6 a e solubilized and pa ially
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hyd olyzed; 2) he supe c i ical hyd olysis eac o (SHR), which con e s he soluble
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compounds in o added alue p oduc s. The ac iona ion line is composed o a wa e deposi
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(D.1), downs eam an Ame ican Lewa EK6 2KN high p essu e pump (P.1, maximum low a e
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1.5 kg/h) p opels wa e h ough a p e-hea e (H.1, 200 cm o 1/8” SS 316 pipe, elec ically
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hea ed by means o wo esis o s o 300 W) which ensu es an uni o m empe a u e a he eac o
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inle . The eac o (R.1), a ube o SS 316, 40 cm leng h, 1.27 cm O.D., is hea ed by h ee la
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esis o s o 300 W each, placed axially along a machined aluminum ba wi h 5.08 cm O.D.
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Bo h, p ehea e and he eac o a e loca ed inside a o me ch oma og aphic o en HP5680. The
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ou - low s eam om he ex ac ion line is mixed wi h he supe c i ical wa e s eam, en e ing in
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a second eac o (SHR) (R.2). The supe c i ical wa e line is composed o a hea e (H.2), a ube
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o 18 m, 1/8 in O.D. SS316 w apped a ound a b ass cylinde and hea ed by wo ca idges and
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wo la esis o s, which p o ided adjus able powe o up o 10 kW, in o de o con ol he
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empe a u e o his s eam. The wa e low was gene a ed by a Mil on Roy XT memb ane pump
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(P.2, maximum low a e 6 kg/h). The SHR allows a as hea ing o he biomass s eam, which
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is mixed almos ins an aneously wi h he supe c i ical wa e s eam, and a apid cooling o he
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p oduc s, which akes place h ough a sudden expansion which e icien ly s ops he hyd olysis.
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In his way, he eac ion ime could be p ecisely calcula ed, as he eac o wo ks iso he mally.
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P essu e was con olled Mic o Me e ing al e 30VRMM4812 om Au ocla e Enginee ing
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(V.4). The se ups o he wo eac o s we e p esen ed in de ail in p e ious wo ks [32, 38].
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An a e age amoun o 6.12±0.03 g o holm oak biomass was placed inside he eac o R.1 o
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each expe imen . Two me allic il e s we e used (po e diame e ≈200 m), loca ed on he op
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and bo om o he eac o , a oiding he elease o he solid du ing he expe imen s. A p essu e
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es wi h cold p essu ized wa e was ca ied ou be o e e e y expe imen , wi h he aim o check
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he p esence o leaks in he sys em. Then, he supe c i ical line was hea ed ensu ing he
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unc ioning o he sys em a equi ed ope a ing condi ions. Once hese condi ions we e s able,
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he pumps we e swi ched o and bo h, he p ehea e and he eac o R.1, we e hea ed up un il
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he empe a u es eached he espec i e se alues. A e wa ds, bo h pumps we e swi ch on
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again and he low and p essu e we e se o he desi ed condi ions, ze o ime is conside ed when
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p essu e eached he desi ed alue.
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A o al o 11 expe imen s we e pe o med (3 ac iona ions and 8 coupled eac ions), ob aining
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a o al o 130 liquid and 11 solid samples, cha ac e ized wi h he me hods desc ibed abo e. Six
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expe imen s we e pe o med a ying he empe a u e in he SHR om subc i ical (350ºC) up o
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supe c i ical (400ºC) condi ions, main aining he p essu e a 250±10 ba . The eac ion ime in
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his eac o was modi ied by a ying he wa e low- a e and changing he eac o olume (2.2
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o 12.4 cm3); eac ion imes be ween 0.25 s and o 12 s we e es ed. Th ee di e en wa e lows
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(11, 17, 26 cm3/min) we e es ed in he ac iona ion line, main aining cons an he a io wi h he
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low o supe c i ical wa e s eam, o ge he desi ed condi ions du ing he u he hyd olysis.
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The eed composi ion o he SHR was analyzed by ca ying ou h ee ac iona ions wi hou he
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second hyd olysis s age, a he same condi ions o empe a u es, low- a es and p essu e es ed
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wi h he coupled eac ion.
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The ac iona ion in he ixed bed eac o was pe o med in wo s ages ma ked by wo dis inc
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empe a u es: 180ºC o ex ac he hemicellulose and 260ºC o emo e mos o he cellulose
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ac ion om he biomass. The hea ing ime be ween bo h se poin s was in he ange o 5-10
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min, while he low was empo a ily s opped o he expe imen unning a 26 cm3/min. In o de
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o ollow he eac ion e olu ion, he pH o he ou le s eam was measu ed online sampling
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e e y 1 minu e. Liquid samples (30-40 cm3) we e aken acco ding he pH a ia ions e e y 5 o
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20 min o he expe imen a 11 cm3/min, and e e y 2 o 8 min o he o he expe imen s. The
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o e all expe imen ime a ied om 110, 60 and 45 min o he uns a 11, 17, 26 cm3/min,
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espec i ely (called he e as (1), (2) and (3)). A e he las sample was g abbed, he hea ing was
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u ned o and he eac o R.1 was le o cool down o oom empe a u e wi h ai lux. Bo h
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pumps we e se o ze o low and he sys em was dep essu ized. The solid was emo ed om he
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eac o , il e ed and d ied 24 h a 105ºC o u he analysis. A e cleaning, he ixed bed
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eac o was placed back, igh ened and he sys em was washed ou wi h deionized wa e .
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3. Resul s and Discussion
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3.1. Biomass ac iona ion
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F om he analysis o he aw holm oak, he amoun o soluble ma e ial was 4.65 ± 0.03g,
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co esponding o 72.1% o he biomass weigh . 3.02 ± 0.02g o his soluble mass we e
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composed o hexoses (C6) and 1.58 ± 0.01g o pen oses (C5). The spa ial ime o he liquid (l),
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is de e mined using he liquid low a e, he eac o olume and he a e age po osi y o he bed
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(i0=0.457±0.01,  =0.948±0.019). The la e was calcula ed by means o Eq. (1), aking in o
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accoun he ini ial and he inal ac ion o oid olume in he bed, due o he sh inking size o
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he biomass pa icles, and also conside ing a cons an densi y o wa e [38] (since i s a ia ion
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wi h empe a u e is less han 2%) and a cons an densi y o he holm oak wood (800 kg/m3, d y
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co esponding o he i s s age o empe a u e in R.1. This ace ic acid exceeded he amoun
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p oduced in he hemicellulose deace yla ion. The e o-aldol pa hway coming om xylose by
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means o glyce aldehyde ou e, could explain he di e ence o ace ic acid ob ained di ec ly
398
om lac ic acid deca bonyla ion. This ex a amoun o ace ic acid could no be conside ed only
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om he hemicellulose sou ce, since he e is also a la ge concen a ion o C6 in he i s ac ion
400
o he eed s eam (see Figu e 2 (a)). This C6 po ion could also con ibu e o he
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glyce aldehyde ou e. Besides, ace ic acid could be ob ained di ec ly om lac ic acid
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deca bonyla ion [15]. Bo h, glucose and xylose, a e able o p oduce lac ic acid by means o he
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e o-aldol pa hway wi h glyce aldehyde and py u aldehyde as in e media ies (see Figu e 3). In
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his sense, hese e o-aldol pa hways could explain he ex a amoun o ace ic acid ob ained a
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longe esidence imes in he SHR. Figu e 4, displays he pH o he ou pu s eam a e he
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ac iona ion s age (expe imen 1) and he coupled p ocess ac iona ion+hyd olysis
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(expe imen s 4, 5, 6 and 8). The pH in he ou le s eam, a e SHR, was always lowe o he pH
408
o he ou pu s eam om he ac iona ion s ep i sel . compa ing he H+ concen a ion o he
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expe imen s du ing he ime pe iod o he i s s age du ing he ex ac ion. This obse a ion
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ag ees wi h he ac ha ex a amoun o ace ic acid was p oduced when a deepe hyd olysis was
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pe o med (see expe imen s 5 and 8). A e his ime pe iod, no di e ence in he pH can be
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de ec ed. Simila beha io was obse ed om expe imen s 6 and 8, howe e , in his case, la ge
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amoun o o mic acid was obse ed compa ed o he expe imen s abo e men ioned in spi e o
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he di e ence o o mic acid p oduced in bo h (see Figu e 2 (c)).
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The p essu e change in he ange s udied, had no e ec on he chemicals dis ibu ion (see Figu e
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2 (c), expe imen s 6 and 7). Unde he condi ions o expe imen 7, pKw is 11.9, calcula ed by
417
means o an empi ic equa ion [45]. This alue is qui e simila han pKw o he expe imen 6. In
418
his way, in spi e o densi y change, he same AVP dis ibu ion is obse ed. Longe esidence
419
ime o expe imen 7 explains he di e ence in oligome s wi h expe imen 6. The dis ibu ion o
420
he AVP o expe imen 6, is independen o he change in pKw, as was discussed abo e o
421
expe imen s 4 and 6. The highes yield o glycolaldehyde-py u aldehyde (calcula ed as mass o
422

p oduc /mass o soluble ma e ial in aw biomass) was ob ained o expe imen 7 (24.4%),
423
p obably due o he combina ion o highe H+ concen a ion and longe .
424
A di e en AVP dis ibu ion is obse ed in he expe imen 9, whe e lac ic acid is he mos
425
abundan p oduc and ace ic acid is deple ed compa ed o he expe imen 4 and 6 (see Figu e 2
426
(d)). This inding could be explained by he sho o he mix u e a high empe a u e,
427
condi ions in which he eac ions a e s opped be o e a e lac ic acid p oduc ion in he e o-
428
aldol ou e, inhibi ing he ace ic acid o ma ion. This selec i i y seems o ake place in he SHR
429
mainly du ing he i s s age o empe a u e in he eac o R.1. A e ha , he o ma ion o lac ic
430
acid in he SHR is educed. This selec i i y seems o ake place mainly du ing he ime pe iod o
431
he i s s age o he ac iona ion, because a e ha , he o ma ion o lac ic acid as well as o
432
glycolaldehyde-py u aldehyde is lowe . The highes yield o lac ic acid was ound a
433
Expe imen 9 (25.5%). The wa e low inc ease in he i s eac o has no clea e ec on he
434
p oduc ion o e o-aldol compounds (see eac ions 10 and 11 in Figu e 2 (d)). Unde hese
435
condi ions, he oligome s b eakup seems o become slowe , since hei amoun is enla ged
436
ela ed o he monome ic suga s. In bo h cases, he e o aldol pa hways a e ollowed p oducing
437
glycolaldehyde-py u aldehyde and lac ic acid wi h simila yields.
438
The combina ion o many a iables in luencing he dis ibu ion o a la ge numbe o
439
p oduc s, in ol ed in a complex eac ion pa h as he desc ibed in Fig. 3, is ha d o be easily
440
explained. Fu he mo e, as was men ioned abo e, we a e dealing wi h he hyd olysis o a eal
441
biomass, in which o he componen s could be in luencing he obse ed beha io .
442
3.3 Hyd olysis kine ic model
443
Aiming o analyze u he he esul s ob ained by he coupled sys em, a kine ic model o he
444
second eac o is p oposed in his sec ion. This model akes in o accoun he solubilized biomass
445
composi ion ed o he second eac o . I was specially ocused on he ime pe iod co esponding
446
o he i s s age o he solubiliza ion (a he condi ions o expe imen 1) since his s ep p oduces
447
an ou le s eam wi h highe amoun o he chemicals o in e es (see las wo columns o Table
448
1). The bigge added alued compounds p oduc ion om s age 1 is due o he ac ha he
449
ope a ional empe a u e was a ound 180 ºC, which means a lowe deg ada ion. The eac ion
450
pa hway p oposed in his case, showed in Figu e 45. I is a simpli ied e sion o he eal
451
hyd olysis desc ibed in Figu e 3. The modelling was done by he ansien egime mass balances
452
o each compound in he luid: oligome s, suga s and p oduc s (Eq. (3)). Mo eo e , he
453
ollowing assump ions ha e been conside ed: (1) he eac ion o de o all he kine ics is 1 o
454
he biomass compound and p o on concen a ion in wa e , (2) he e a e no di usional e ec s in
455
luid phase, (3) kine ic cons an s ollows A henius’ law and (4) he eac o wo ks a he same
456
empe a u e a any poin . Rega ding kine ics, a con en ional exp ession was used including he
457
e ec o he concen a ion o wa e p o on since i is a hyd olysis p ocess (Eq. (4)).
458
𝛿𝐶𝐿𝑗
𝛿𝑡 =𝑟𝑗−𝑢
𝐿·𝛿𝐶𝐿𝑗
𝛿𝑧
(3)
𝑟𝑗=C𝐻+ ·∑∝𝑖,𝑗·𝐾𝐿𝑖·𝐶𝐿𝑖
𝑖=𝑁
𝑖=1
(4)
(4)
459
3.3.1 Nume ical esolu ion
460
Eq. (3) is a se o 6 pa ial di e en ial equa ions (PDE) which has o be disc e ized o ob ain a
461
se o o dina y di e en ial equa ion (ODE). The esolu ion o his se o ODEs was pe o med
462
by he Runge-Ku a’s me hod wi h a 8 h con e gence o de and he disc e iza ion by coupling
463
o hogonal coloca ion me hod on ini e elemen s [46]. The i ing o he expe imen al da a
464
cons i u es an op imiza ion p oblem. Due o i s complexi y, i was p e iously seeded by manual
465
i e a ion, and hen, op imized by he Nelde -Mead-Simplex me hod. Mo eo e , as he inle
466
concen a ion o he hyd olysis eac o was a iable and he oligome p ope ies changed wi h
467
ex ac ion ime [47], he p oblem was op imized a e e y expe imen al poin . Finally, he
468
solu ion was e iewed in o de o ensu e he physical meaning o he pa ame e s. The objec i e
469
unc ion was he minimiza ion o he Absolu e A e age De ia ion (A.A.D., Eq. (5)) o
470
oligome , suga and p oduc s concen a ion a he SHR ou pu .
471
472
473
474
𝐴.𝐴.𝐷.=∑1
𝑛·|𝑋𝑒𝑥𝑝−𝑋𝑠𝑖𝑚
𝑋𝑒𝑥𝑝 |·100
𝑛
𝑖=1 (5)
3.3.2 Expe imen al da a i ings
475
In o de o alida e he model, only expe imen s 4, 6 and 9 we e used because hey we e
476
ca ied ou a simila esidence imes and h ee di e en empe a u es (see Table 1). Fo
477
expe imen 4, he da a a ex ac ion ime o 9 and 14 min we e no conside ed because hey do
478
no ollow he endency ixed by he se o he h ee expe imen s used (4, 6 and 9). Mo eo e , as
479
each expe imen was ca ied ou independen ly, he inle o he eac o was assumed o ha e he
480
same composi ion ha expe imen 3 1 bu wi h TOC p o ile o he i ed expe imen (4, 6 and
481
9). I is also ema kable ha he olume ic low was he addi ion o he p o ided low by he
482
wo pumps o all he expe imen s (see Figu e 1). The de ia ion be ween he model and he
483
expe imen al da a is a ayed in Table 2 and o expe imen 6 i also can be seen in Figu e 6. The
484
model was able o ep oduce success ully he hyd olysis o solubilized biomass, being he
485
a e age A.A.D. 21.14 %, 37.37 %, 18.41 % and 7.24 % o ins an hemicellulose and cellulose
486
oligome s, suga s C6, suga s C5 and hei deg ada ion p oduc s ( he added alue p oduc s
487
espec i ely o AVP). These disc epancies changed o 27.46 %, 7.61 %, 9.31 % and 3.99%
488
espec i ely when cumula ed alues we e used. Taking in o accoun hese las alues, i can be
489
checked ha he highes e o is in he es ima ion o he oligome s mass, which can be caused
490
by he ac ha he expe imen al da a we e ob ained by he di e ence be ween he TOC and he
491
sum o he o he compounds (suga s and AVP). Mo eo e , he de ia ion be ween he
492
expe imen al and simula ed TOC was also calcula ed in o de o check ha he mass
493
conse a ion law is ollowed. Fo all he cases, his mass balance de ia ion esul in ze o pe cen
494
wi h h ee signi ican igu es (0.00%). The kine ic cons an s and he s oichiome ic coe icien s
495
(𝐾𝐿𝑖 and ∝𝑖,𝑗 in Eq. (4), espec i ely) had o be ob ained om i ing. Rega ding o ∝𝑖,𝑗, i was
496
always 1 less o he inal p oduc s coming om hemicellulose oligome s since hey a e
497
composed by pen oses and hexoses [48, 49]. These i ed pa ame e s, which a e shown in Table
498
4, equi e a deepe analysis and hey a e discussed in he nex sec ion.
499
3.3.3 Analysis o kine ic pa ame e s
500
The dependence o he kine ics pa ame e s wi h empe a u e was p o ed. The eg ession
501
coe icien (R2) acco ding he A henius’ heo y was highe han 0.84 o all he cases (see
502
Table 3). No change in he kine ic beha io was obse ed h ough he c i ical poin (see Table
503
3) like does in he hyd olysis o mic oc ys alline cellulose [44, 50] acco ding o he commen ed
504
in sec ion 3.2.2, since he e is no simul aneous solubiliza ion in he SHR. Howe e , a
505
dependence o he kine ic beha io was obse ed wi h he ex ac ion ime, since he a es o
506
p oduc ion o aluable chemicals is dec eased a e he maximum o solubilized mass is eached
507
(see Figu e 7 (a) and (b)). This obse a ion could be ela ed wi h he in luence o some o he
508
chemicals p oduced by he u he hyd olysis o suga s on he hyd o he mal hyd olysis. In
509
addi ion, i is also in e es ing ha a e his change, he kine ics o he suga ans o ma ion end
510
o hei ini ial alue while he kine ic o he oligome b eakdown g ows exponen ially. This
511
di e ence would be o igina ed by he changes in he molecula weigh o he ex ac ed
512
oligome s and he ac ha hey would be ans o med mo e quickly i he molecula weigh is
513
lowe . Mo eo e , i can be seen ha empe a u e can compensa e his nega i e e ec , being
514
negligible o oligome s a 400ºC (Figu e 7 (c)).
515
O he in e es ing esul is he e olu ion o he a io be ween he ou kine ic cons an s. In
516
sec ion 3.2.1 i was indica ed ha suga ans o ma ion is as e han oligome clea age in
517
subc i ical condi ions and lowe in supe c i ical wa e . This beha io ag ees wi h he ob ained
518
om he i ings, bu only be o e he ime o maximum o ex ac ion (Figu e 7 (a) and (c)). So,
519
om his poin , he changes in molecula weigh and he aw ma e ial ans o ma ion makes he
520
oligome clea age always g ea e . As he oligome composi ion changes wi h ex ac ion ime,
521
he kine ic canno be ep oduced by a ypical A henius’ kine ic. So, wo equa ions unc ion o
522
his ime ( e) a e p oposed, one o he p e-exponen ial ac o oligome clea ing (Eq. 46) and
523
o he o he ac i a ion ene gy suga u he eac ions (Eq. 57).
524
P=C·| emax −A· e|B (46)
525
526
P=D+ E
1+e(F·( e−G)) (57)
527
528
Whe e P e e s o bo h, he ac i a ion ene gy (Ea/R) and he na u al loga i hm o he p e-
529
exponen ial ac o (ln(k)). In Eq. 46, he pa ame e C is he na u al loga i hm o he p e
530
exponen ial ac o o ac i a ion ene gy a he maximum ex ac ion ime (𝑡𝑒𝑚𝑎𝑥) and pa ame e s
531
A and B in oduce he e ec o he changes in he s uc u e and eac ion medium. A would be
532
ela ed wi h he s ong o he compound agains i s deg ada ion by hyd olysis. B would be a
533
measu e o how s uc u e o eac ion medium can accele a e o es ain he deg ada ion. In Eq.
534
57, D is he p e exponen ial ac o o he ac i a ion ene gy a he ime whe e he bigges
535
solubiliza ion akes place, E and F, a e he pa ame e s ha conside he ole o he s uc u e and
536
eac ion medium and G is he ime when he maximum ex ac ion is eached. In his case, E
537
would ep esen how he medium o he s uc u e can enhance he hyd olysis o hinde i . F
538
would be he compound esis ance agains deg ada ion.
539
Finally, he e olu ion o he hexoses con en in hemicellulose oligome s is ep esen ed in
540
Figu e 7 (b). I can be obse ed ha he a io be ween hese alues g ows wi h ime. This esul
541
was expec ed because hexoses would make he dissolu ion mo e di icul and would explain he
542
ac ha in expe imen 5 he ex ac ion was as e han 4 and 9 expe imen s (see Figu e 7 (c)).
543
Mo eo e his esul ag ee wi h he da a epo ed by o he au ho s [51].
544
3.3.4 Simula ed expe imen s
545
As i was men ioned in sec ion 3.3.2, only expe imen s 4, 6 and 9 we e used o alida e he
546
model. Expe imen s 5 and 8 we e no conside ed because hei eac ion ime we e much highe ,
547
which implies almos a o al con e sion a he eac o ou le . Howe e , i checked i he model
548
was able o ep oduce hei beha io . The esul o he simula ions a e p esen ed in Figu e 8,
549
being he absolu e de ia ion a ound 4% o bo h expe imen s. The e o e, he model can p edic
550
success ully he hyd olysis a bo h low (0.2 – 1.0 s) and high (11.1-12.5 s) esidence imes.
551
3.3.5 Model limi a ions
552
F om he esul s showed in he h ee p e ious sec ions, he model was able o success ully
553
ep oduce he expe imen al beha io o he se -up. In ac , his model can be used o any o he
554
lignocellulosic biomass because o he ac ha i has been de eloped o a gene al biomass
555
hyd olysis pa hway. Howe e , i is limi ed o p ocesses whe e soluble lignin is low and when
556

he aim is o ep oduce he o e all beha io o a solubilized biomass s eam hyd olysis ins ead
557
o an analysis o each indi idual compound. Fu he mo e, his model can be also adap ed o
558
p ocesses whe e he inle s eam is a iable in ime.
559
Conclusions
560
A new p ocess coupling ac iona ion and hyd olysis s eps was de eloped. By means o his
561
p ocess, up o 64.2% o eed Holm oak wood was solubilized mainly as oligome s o hexoses
562
and pen oses and suga s wi h a small ac ion o e o-aldol compounds. The low a io o he
563
amoun o oligome s o monome ic suga s in he ou le s eam could be explained by a simila
564
beha io han in he case o pu e cellulose hyd olysis: he a e o monome s hyd olysis is highe
565
o he oligome s b eak up in subc i ical condi ions, bu his endency is e e ed a supe c i ical
566
empe a u es.
567
The main p oduc s o he u he hyd olysis in he second eac o we e glycolaldehyde,
568
py u aldehyde and lac ic acid. Yield ( ela ed o he amoun o soluble suga s in he aw
569
biomass) o 24 w % o Glycolaldehyde-Py u aldehyde was ound a long eac ion imes (350ºC,
570
160ba and 8,6 s) and 25 w % o lac ic acid was ound a sho eac ion ime bu high
571
empe a u e (400ºC, 250 ba and 0.23s). An inc easing amoun o ace ic acid was obse ed a
572
he highes esidence imes (e.g. 12 s).
573
The dis ibu ion o p oduc s is ela ed wi h a combined eac ion hyd olysis pa hway o
574
cellulose and hemicellulose in ol ing oligome clea age o monome s, isome iza ion s eps and
575
wo compe ing pa hs: Re o-aldol condensa ion and dehyd a ion. The in luence o he wa e
576
densi y and he amoun o ions H+ coming om he dissocia ion p ocess is no clea as i is in
577
he case o he hyd olysis o pu e cellulose, in which he glucose dehyd a ion is highly inhibi ed
578
and e o aldol pa hways clea ly a o ed a empe a u es and p essu es abo e he wa e c i ical
579
poin . In he p esen wo k, p oduc s coming om e o-aldol pa hs as well as p oduc s o
580
dehyd a ion a e obse ed in bo h condi ions: sub and supe c i ical. Finally, a gene al kine ic
581
modelling o he hyd olysis eac o was p oposed. This model could ep oduce he expe imen al
582
da a o suga and added alue p oduc s wi h de ia ions lowe han 10%. Besides, he calcula ed
583
kine ic pa ame e s ep oduced he changes in oligome and suga con e sion when he
584
hyd olysis is pe o med in supe c i ical condi ions ins ead o in subc i ical wa e . This model
585
can be applied o any o he lignocellulosic biomass wi h a low con en o soluble lignin.
586
The main ad an age o his combined p ocess consis in p o iding a lique ied biomass
587
s eam o a selec i e hyd olysis eac o gi ing he alo iza ion o he aw ma e ial a oiding he
588
cos ly g inding o pa icles om se e al millime e s o less han wo hund ed mic ons needed o
589
pump i in a wa e s eam belonging o a high p essu e p ocess.
590
591
Acknowledgemen s
592
The au ho s acknowledge he Spanish “Minis e io de Economía y Compe i i idad
593
(MINECO)” and FEDER unds, P ojec BioF aHyne y CTQ2015-64892-R and he egional
594
go e nmen (Jun a de Cas illa y León), P ojec Re e ence: VA330U13 o unding. MEng.
595
Gianluca Gallina wishes o acknowledge he Spanish “Minis e io de Economía y
596
Compe i i idad (MINECO)” o he schola ship/p edoc o al con ac BES-2013-063556. MEng.
597
Al a o Cabeza would like o hank o he Spanish “Minis e io de Educación, Cul u a y
598
Depo e”, aining p og am o uni e si y p o esso s ( e e ence FPU2013/01516) o he esea ch
599
aining con ac .
600
601
Abb e ia ions and symbols
602
Ac onyms
603
604
A.A.D.: A e age absolu e De ia ion.
605
Olig: Hemicellulose and cellulose oligome s.
606
C6/OligC5: a io hexoses o hemicellulose oligome s.
607
G eek le e s and symbols
608
609
A-G: Pa ame e s o kine ics cons an es ima ion.
610
∝𝑖,𝑗 : S oichiome ic coe icien o he compound “j” o he eac ion “i”, dimensionless.
611
𝐶𝐻+ : Concen a ion o he p o ons, mg/L.
612
𝐶𝐿𝑗 : Concen a ion o he compound “j”, mg/L.Ea/R: Ac i a ion ene gy, K.
613
ε: Po osi y o he bed, dimensionless.
614
ε : Po osi y o he bed, calcula ed a he end o he expe imen , dimensionless.
615
εa : A e age po osi y o he bed, be ween he beginning and he end o he expe imen ,
616
dimensionless.
617
εo: Po osi y o he bed, calcula ed a he end o he expe imen , dimensionless.
618
𝐾𝐿𝑖 : Kine ic cons an , min-1.
619
k: P e-exponen ial ac o o he kine ic cons an , mg-1·min-1.
620
L: Leng h o he eac o , m.m0: ini ial mass o he solid in he eac o , g.
621
m : inal mass o he solid in he eac o , g.
622
m(i) (RM): o al amoun o componen (i) in he aw ma e ial, ex ac ed by acid hyd olysis and
623
de ec ed by HPLC analysis, g.
624
Mw(i): molecula weigh o componen i, g/mol.
625
𝑀𝑤𝐶 : molecula weigh o he a ca bon a om, g/mol.
626
msol o (RM): o al amoun o soluble compounds in he aw ma e ial, ex ac ed by acid
627
hyd olysis and de ec ed by HPLC analysis, g.
628
N: Numbe o compounds, dimensionless.
629
n: To al numbe o expe imen s, dimensionless.
630
n(i): Numbe o ca bon a oms in he soluble componen i, dimensionless.
631
P: Calcula ed kine ic pa ame e , ac i a ion ene gy o he na u al loga i hm o he p e-
632
exponen ial ac o
633
R2: Coe icien R2, dimensionless.
634
: a io be ween he molecula weigh o he soluble compounds ex ac ed and he molecula
635
weigh o he a oms o ca bon, dimensionless.
636
(i): a io be ween he molecula weigh o he soluble compounds ex ac ed and he molecula
637
weigh o he a oms o ca bon o compound i, dimensionless.
638
𝑟𝑗 : Reac ion a e o he compound “j”, mg/min·L.
639
u: Liquid eloci y in he eac o , m/min.
640
: Residence ime in he SHR, s.
641
𝑡𝑒: Ex ac ion ime, min.
642
𝑡𝑒𝑚𝑎𝑥 : Maximum ex ac ion ime, min.
643
𝑥𝑖𝐸𝑋𝑃 : Expe imen al alue o he i ed a iable.
644
𝑥𝑖𝑆𝐼𝑀 : Simula ed alue o he i ed a iable.
645
z: Coo dina e along he leng h o he eac o , dimensionless.
646
647
648
649
650
651
652
D.1
D.2
P.2
P.1
H.1
H.2
R.1
R.2
V.4
V.1
V.2
H.3
D.4
D.3
V.3
V.5
Wa e
Sample
Deposi
P
Wa e
P
T
T
T
P
T
pH
k1: Cellulose oligome b eakup kine ic cons an , k2: Hemicellulose oligome b eakup kine ic
842
cons an , k3: Suga s C6 hyd olysis kine ic cons an , k4: Suga s C5 hyd olysis kine ic cons an .
843
Figu e 8. Compa ison be ween he expe imen al and simula ed da a o AVP in expe imen 5
844
and 8.
845
Symbols a e he expe imen al da a and ull lines shows he p edic ion o he model wi h
846
op imized kine ic pa ame e s o each da a.
847
848
Figu e 1.
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869

870
871
Figu e 2.
872
873
874
875
876
877
878
879
0
1
2
3
4
5
0.0
0.5
1.0
1.5
2.0
020 40 60 80 100
0.00
0.05
0.10
0.15
0.20
020 40 60 020 40
99.8%
TOC
HPLC
Soluble mass [g]
81.2%
(C5+C6) o al=88.3 % w
80.2%
81.5%
73.1%
80.3%
C6
C5
Oligo C6
Oligo C5
Suga s [g]
(C5+C6) o al=88.4 % w
(C5+C6) o al=84.0 % w
(3)(2)
(1)
Glice aldehyde
Pi u .+Glycolaldehyde
Fo mic acid
Lac ic acid
Ace ic acid
5HMF
AVP od [g]
(a)
ime [min]
880
881
882
883
884
885
886
887
888
889
0
1
2
3
4
5
0.0
0.2
0.4
0.6
0.8
1.0
020 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
020 40 60 80 100
TOC
HPLC
70.1%
88.3%
81.2%
108.6%
C6
C5
Oligo C5+C6
Soluble mass [g]
Suga s [g]
AVP od [g]
xOligo=86.5% xOligo=99.9%
Glyce aldehyde
Fo mic acid
Py u .+Glycolaldehyde
Lac ic acid
Ace ic acid
5HMF
ime [min]
377º, 251ba , 11.1s
383º, 245ba , 1.1s
(b) (5)
(4)
890
891
892
893
894
895
0
1
2
3
4
5
0.0
0.2
0.4
0.6
0.8
1.0
020 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
020 40 60 80 100 020 40 60 80 100
TOC
HPLC
70.7%
85.9%
(7)
79.8%
103.0%
xOligo=85.7%
C6
C5
Oligo C5+C6
Soluble mass [g]
Suga s [g]
AVP od [g]
xOligo=98.7%
xOligo=99.7%
350ºC, 240ba , 12.5s
356ºC, 162ba , 8.3s352ºC, 241ba , 2.1s
(c)
Glyce aldehyde
Fo mic acid
Py u .+Glycolaldehyde
Lac ic acid
Ace ic acid
5HMF
ime [min]
(8)
(6)
93.9%
74.6%
896
897
898
899
900
901
902
903
904
905
0
1
2
3
4
5
0.0
0.2
0.4
0.6
0.8
1.0
020 40 60
020 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
020 40
TOC
HPLC
77.3%
102.7%
(10)
68.5%
83.3%
xOligo=99.3%
C6
C5
Oligo C5+C6
Soluble mass [g]
Suga s [g]
AVP od [g]
xOligo=87.2%
ime [min]
398ºC, 260ba , 0.24s
401ºC, 252ba , 0.24s
396ºC, 249ba , 0.23s
(d)
Glyce aldehyde
Fo mic acid
Py u .+Glycolaldehyde
Lac ic acid
Ace ic acid
5HMF
(11)
(9)
82.7%
71.1%
xOligo=74.6%
Figu e 3.
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
Figu e 4.
922
923
924
925
926
927
020 40 60 80 100 120
2
3
4
5
6
(1)
(4)
(5)
(6)
(8)
pH
ime [min]
O
O
H
Fo mic Acid
O
H
O
H
O
O
H
O
H
O
H
O
O
O
H
O
O
H
O
O
H
O
H
O
O
C
H
3
O
H
O
H
O
O
H
O
H
O
H
O
H
O
H
O
O
H
O
O
H
O
H
O
H
O
H
O
O
H
O
H
O
H
O
H
O
H
O
O
H
O
D
-
Glucose

-
Gluco
py ano
se
5
-
HMF
Gl
yce aldehyde
Dihyd oxy
ace one
Py u aldehyde
Glycolaldehyde
O
C
H
3
O
H
O
H
Lac ic Acid
C5 Oligome s
O
H
O
C
H
3
O
O
O
H
Fo mic Acid
Le ulinic
Acid
C6 Oligome s
O
O
Fu u al
+
Xylose
Ace ic Acid
O
HO
F uc ose

Figu e 5.
928
929
930
931
932
Figu e 6.
933
934
935
936
937
938
939
940
Figu e 7.
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
C6 Oligome s
C5 Oligome s
Suga s C6
Suga s C5
Added Value
P oduc s
H+
H+
H+
H+
H+
k1
k2
k3
k4
10 20 30 40 50
0.0
0.4
0.8
1.2
1.6
2.0
2.4 TOC
AVP
TOC, AVP [g]
0.0
0.2
0.4
0.6
Oligome s
C5
C6
Oligome s, C5,C6 [g]
ime [min]
30
31
32
33
33
34
35
10 20 30 40 50
34
36
38
a)
c)
b)
ln ki
k1
k2
k3
k4
ime [min]
0.0
0.1
0.2
0.3
0.4
10 20 30 40 50
0.0
0.2
0.4
0.6
0.8
1.0
C6/Oligo C5 [g/g]
4
6
9
d)
e)
mass solubilized [g]
ime [min]
Figu e 8.
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
10 20 30 40 50
0.0
0.2
0.4
0.6
0.8
5
8
AVP [g]
ime [min]
Table 1.
978
979
Exp
T
[ºC]
P
[ba ]
1
[s]
QSHR 2
[cm3/min]
MBTOC3
[%]
xOligome s4
[%]
Y1AVP5
-
Y2AVP6
-
4
383.7 ± 5.1
245.7 ± 4.6
1.06
36.0
92.2
86.5
0.008
0.079
5
377.2 ± 3.5
251.9 ± 5.9
11.15
38.5
105.9
99.9
0.247
0.281
6
352.5 ± 4.4
241.3 ± 3.7
2.10
35.2
89.3
85.7
0.004
0.109
8
349.9 ± 2.4
239.6 ± 4.2
12.50
35.8
103.1
98.7
0.233
0.132
9
396.1 ± 3.6
249.1 ± 5.1
0.23
36.8
103.6
99.3
0.440
0.254
10
401.2 ± 2.8
252.2 ± 3.9
0.24
90.1
93.0
87.2
0.481
0.278
11
398.3 ± 3.0
259.9 ± 3.4
0.24
106.2
91.2
74.6
0.530
0.228
1 : eac ion ime in hyd olysis eac o , 2 Flow a e in he SHR, 3 Global mass balance o he coupled p ocess,
980
4Con e sion o oligome s om hemicellulose and cellulose, 5,6 Yields o added alue p oduc s in he ime pe iod o
981
he i s and second s age o empe a u e du ing ac iona ion Yi=massi / mass soluble ma e ial in aw biomass
982
983
984
Table 2.
985
ADD %
Ins an aneous
Cumula ed
Expe imen
Oligome s1
C62
C53
AVP4
Olig1
C62
C53
AVP4
4
21.70
21.88
21.92
7.38
26.85
10.78
4.98
7.52
6
20.58
29.11
22.16
6.27
6.99
2.15
14.82
1.78
9
*
61.04
11.15
8.07
48.53
9.90
8.15
2.66
A e age
21.14
37.34
18.41
7.24
27.46
7.61
9.31
3.99
5
*
*
*
5.77
*
*
*
4.94
8
*
*
*
0.93
*
*
*
1.02
A e age
*
*
*
4.65
*
*
*
3.32
1 Oligome s om hemicellulose and cellulose, 2 Suga s C6, 3 Suga s C5,4 deg ada ion p oduc s. * Compound no
986
de ec ed. ADD% o o al o ganic con en was 0.0.
987
988
989
990
991
992
Table 3.
993
994
e1[min]
k1a
k2b
k3c
k4d
R2
19
0.88
0.87
0.99
0.999
26
0.88
0.86
0.99
0.98
35
0.87
0.85
0.99
0.97
44
0.93
0.89
0.9999
0.96
A e age
0.89
0.87
0.99
0.97
a Cellulose oligome clea age cons an , b Hemicellulose oligome clea age cons an , c Suga s C6 hyd olysis kine ic
995
cons an , d Suga s C5 hyd olysis kine ic cons an . 1 F ac iona ion ime.
996
997
998
Table 4.
999
k1a
ln(k)e
Ea/R
k2b
ln(k)e
Ea/R
-
[K]
-
[K]
A
1.04
1.03
A
1.08
1.08
B
0.04
0.06
B
0.03
0.05
C
106
46,543
C
109
48,553
k3c
ln(k)e
Ea/R
k4d
ln(k)e
Ea/R
-
[K]
-
[K]
A
3.26
2069
A
2.85
1834
B
22.05
24.22
B
21.25
20.15
C
1.35
4.01
C
1.70
3.58
D
87.32
35,238
D
89.63
36,081
a Cellulose oligome b eakup cons an , b Hemicellulose oligome b eakup cons an , c Suga s C6 hyd olysis cons an ,
1000
d Suga s C5 hyd olysis cons an , e Na u al loga i hm o he A henius’ p e-exponen ial ac o , Ac i a ion ene gy.
1001
1002