Production of jet and diesel fuel range alkanes from waste hemicellulose-derived aqueous solutions

Transcription

1 University of Msschusetts Amherst From the SelectedWorks of George W. Huber 2010 Production of jet nd diesel fuel rnge lknes from wste hemicellulose-derived queous solutions George W Huber, University of Msschusetts - Amherst R. Xing A. Subrhmnym H. Olcy W. Qi, et l. Avilble t:

2 Cutting-edge reserch for greener sustinble future olume 12 Number 11 November 2010 Pges ISSN COER ARTICLE Huber et l. Production of jet nd diesel fuel rnge lknes from wste hemicellulose-derived queous solutions (2010)12:11;1-C

3 PAPER Green Chemistry Production of jet nd diesel fuel rnge lknes from wste hemicellulose-derived queous solutions Rong Xing, Ayygri. Subrhmnym, Hkn Olcy, Wei Qi, G. Peter vn Wlsum, b Hemnt Pendse b nd George W. Huber* Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 Received 25th June 2010, Accepted 27th August 2010 DOI: /c0gc00263 In this pper we report novel four-step process for the production of jet nd diesel fuel rnge lknes from hemicellulose extrcts derived from northestern hrdwood trees. The extrct is representtive of byproduct tht could be produced by wood-processing industries such s biomss boilers or pulp mills in the northestern U.S. The hemicellulose extrct tested in this study contined minly xylose oligomers (21.2 g/l xylose fter the cid hydrolysis) s well s 0.31 g/l glucose, 0.91 g/l rbinose, 0.2 g/l lctic cid, 2.39 g/l cetic cid, 0.31 g/l formic cid, nd other minor products. The first step in this process is n cid-ctlyzed biphsic dehydrtion to produce furfurl in yields up to 87%. The furfurl is extrcted from the queous solution into tetrhydrofurn (THF) phse which is then fed into n ldol condenstion step. The furfurl-cetone-furfurl (F-Ac-F) dimer is produced in this step by rection of furfurl with cetone in yields up to 96% for the F-Ac-F dimer. The F-Ac-F dimer is then subject to low-temperture hydrogention to form the hydrogented dimer (H-FAF) t C nd 800 psig with 5 wt% Ru/C ctlyst. Finlly the H-FAF undergoes hydrodeoxygention to mke jet nd diesel fuel rnge lknes, primrily C 13 nd C 12,inyieldsupto91%.Thetheoreticlyieldfor this process is 0.61 kg of lkne per kg of dry xylose derived from the hemicellulose extrct. Experimentlly we were ble to obtin 76% of the theoreticl yield for the overll process. We estimte tht jet nd diesel fuel rnge lknes cn be produced from between $2.06/gl to $4.39/gl depending on the feed xylose concentrtion, the size of the biorefinery, nd the overll yield. Sensitivity nlysis shows tht the prices of rw mterils, the orgnic-to-queous mss rtio in the biphsic dehydrtion, nd the feed xylose concentrtion in the hemicellulose extrct significntly ffect the product cost. 1. Introduction Diminishing fossil resources nd growing environmentl concerns increse the need to develop lterntive renewble sources nd technologies for the production of fuels nd chemicls. 1,2 Jet nd diesel fuels, s importnt liquid trnsporttion fuels, re essentil for modern economies. They re currently primrily produced from petroleum-bsed crude oils. Incresing demnd for trnsporttion fuels requires the sustinble production of jet nd diesel fuels. This cn be ccomplished using nonfood lignocellulosic biomss s feedstock. 2,3 Lignocellulosic biomss nd its derivtives hve been processed in diverse wys to mke hydrogen, 2,4 6 chemicl intermedites, 7,8 nd liquid hydrocrbon fuels including bio-oils, 9 romtic hydrocrbons, nd bioethnols ,16 egetble oils cn lso be hydro-treted Deprtment of Chemicl Engineering, University of Msschusetts, Amherst, 686 North Plesnt Street, 159 Goessmnn Lb, Amherst, MA, 01003, USA. E-mil: huber@ecs.umss.edu; Fx: ; Tel: b Chemicl nd Biologicl Engineering Deprtment, Forest Bioproducts Reserch Institute (FBRI), University of Mine, 5737 Jenness Hll, Orono, ME, , USA. Electronic supplementry informtion (ESI) vilble: Tbles S1 nd S2. See DOI: /c0gc00263 to produce stright-chin lknes tht cn fit in the jet nd diesel fuels rnge. 17 We hve lso used queous-phse hydrodeoxygention to mke gsoline rnge lknes from both crbohydrtes nd bio-oils. 4,5,18 However, these lighter lknes re not suitble to serve s jet nd diesel fuel components due to their high voltility. Jet fuels re complex hydrocrbon mixture consisting of different clsses such s prffin, nphthene, nd romtics. The rnge of their sizes (crbon numbers or moleculr weights) is restricted by the requirement for the product, for exmple, the distilltion profile, the freezing point or smoke point. 19 Currently, Jet-A nd JP-8 re used to power civilin nd militry ircrfts. Typiclly JP-8 consists of n-prffin rnging from C 8 C 15 (~35 wt%), brnched prffin rnging from C 8 C 15 (~35 wt%), romtics rnging from C 7 C 10 (18 wt%) nd cycloprffin rnging from C 6 C 10 (7 wt%). 20 Huber et l. 21 first presented ctlytic process for the conversion of biomss-derived crbohydrtes to liquid lknes (C 7 C 15 ) tht serve s jet nd diesel fuel components in four-phse rector system. In the Huber et l. work they used model compounds for this process. The first step in this process is dehydrtion step to produce furfurl from C 5 sugrs nd 5-hydroxylmethylfurfurl (HMF) from C 6 sugrs. Dumesic nd co-workers lter developed highly efficient biphsic process tht ws ble to produce HMF nd furfurl This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,

4 Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 Fig. 1 in high yields. 1,22 The furfurl nd HMF re then rected with cetone by bse-ctlyzed ldol condenstion step to produce lkne precursors, e.g., monomers nd dimers. These monomers nd dimers re then converted into stright-chin lknes by dehydrtion/hydrogention step. While this initil process looks promising for the production of lrge stright lknes for jet nd diesel fuels, to dte reserchers hve only used model biomss compounds tht do not contin the impurities present in biomss feedstocks. In this pper we use queous crbohydrte solutions derived from northestern hrdwood trees. Aqueous crbohydrte feedstocks could be produced s by-product strem by wood-processing industries tht obtin reltively low vlue from hemicelluloses. 16,23,24 The extrct used in this study ws derived through hot-wter extrction nd is representtive of process strem tht could be produced t biomss power plnt or composite wood mnufcturing fcility. The four steps to mke jet nd diesel fuel rnge lknes require process integrtion nd optimiztion. In this pper we show how this process could be integrted, nd lso perform n economic nlysis. As of tody, there hs been no report on the direct use of lignocellulosic hydrolystes for the production of diesel nd jet fuel rnge lknes. The objective of this pper is to report on novel integrted four-step process by which jet nd diesel fuel rnge lknes (C 8 C 13 ) cn be produced from hemicellulosederived queous solutions nd show tht high yields of lknes cn be chieved under optimized conditions. Fig. 1 depicts the key rection chemistry involved in the production of tridecne from the hemicellulose extrct. This process includes four steps: (1) cid hydrolysis nd xylose dehydrtion, (2) ldol Rection chemistry for the conversion of xylose oligomers into tridecne. condenstion, (3) low-temperture hydrogention, nd (4) hightemperture hydrodeoxygention. The hemicellulose extrct we used in this work ws produced by extrcting wood chips with hot wter in custom-built rotting digester t the University of Mine Process Development Center. 24 The first step in our process is combined cid hydrolysis of xylose oligomers nd biphsic dehydrtion of xylose. The hemicellulose extrct contins monomeric xylose nd xylose oligomers (~1.3 g/l xylose monomer nd ~19.9 g/l xylose oligomers). The xylose oligomers re first converted into monomeric xylose through the cid-ctlyzed hydrolysis. 25 The xylose monomers re then converted into furfurl nd wter through the cid-ctlyzed dehydrtion. The dehydrtion of pure xylose into furfurl hs been studied in monophsic, 26 biphsic (orgnic nd queous phse, single solvent nd solid cids) 22,27,28 nd triphsic rection systems (orgnic, queous phse nd solid cids), 27,29 using ctlysts such s minerl cids, 22,26,28 solid cids. 27,30 Among them, the rection systems consisting of both orgnic nd queous phse showed simultneously high xylose conversion nd high selectivity for furfurl. Dis nd coworkers reported tht 91% conversion of xylose nd 83% selectivity of furfurl could be chieved by using toluene wter s solvent over micro-mesoporous sulfonic cid ctlysts. 27 Dumesic nd co-workers obtined 71% conversion of xylose nd 91% selectivity of furfurl using 7 : 3 (w/w) methyl isobutyl ketone (MIBK) 2-butnol s solvent with HCl s ctlyst. 22 In the biphsic systems, the orgnic solvent is usully used s n extrcting solvent tht extrcts furfurl from the queous phse to void undesired decomposition rections of furfurl which produce formic cid, 31 nd solid humins. 32 In 1934 Green Chem., 2010, 12, This journl is The Royl Society of Chemistry 2010

5 Tble 1 Chemicl compositions of the un-hydrolyzed nd hydrolyzed hemicellulose extrct (H-extrct) used in this study Concentrtion (g/l) H-extrct Glucose Xylose Arbinose Lctic Acid Formic Acid Acetic Acid HMF Furfurl TOC (ppm) % Crbon Identified Un-hydrolyzed Hydrolyzed Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 the present work, THF ws selected s the extrcting solvent due to its gret ffinity for furfurl, low boiling-point (66 C), low vporiztion het (30 kj/mol), nd ese of seprtion from wter. The ddition of simple slts to the queous phse ws found to improve the seprtion of orgnic nd queous phses due to the slting-out effect. 1 We dded NCl into the hemicellulose extrct in order to enhnce the prtitioning of furfurl into the orgnic phse. In the second step, furfurl rects with cetone to form precursors of jet nd diesel fuel rnge lknes vi the bsectlyzed ldol condenstion. Aldol condenstion occurs between two crbonyl groups (with t lest one rective -hydrogen in either crbonyl group) over n cid or bse ctlyst, to form b-hydroxycrbonyl derivtive followed by dehydrtion to produce,b-unsturted crbonyl compounds Accordingly, ldol condenstion of equl molr mounts of furfurl nd cetone mkes F-Ac monomer (C 8 species), while 2 moles of furfurl with 1 mole of cetone produce F-Ac-F dimer (C 13 species), s illustrted in Fig. 1. In this work the rection ws optimized to mke high yields of F-Ac-F dimer. The third step in our process is low-temperture hydrogention. The purpose of this step is to stbilize the F-Ac-F dimer by producing hydrogented F-Ac-F (H-FAF, spiro H-dimer or lcohol H-dimer in Fig. 1). F-Ac-F is unstble nd will polymerize even t room temperture due to the presence of vrious unsturted bonds. This step lso helps void undesired plugging of rectors used in the subsequent hydrodeoxygention step. In our work, the 5 wt% Ru/C powder ctlyst ws used due to its high rectivity nd high efficiency of hydrogenting the double bonds. 5 The hydrogented dimers then undergo the lst step of hydrodeoxygention to produce tridecne. In our work, 4 wt% Pt/SiO 2 Al 2 O 3 ctlyst ws used due to its bi-functionl properties. 4 5,35 ThecidicSiO 2 Al 2 O 3 ctlyzes the dehydrtion of H-dimers to form C C bonds nd wter, nd the C C bonds re hydrogented over Pt. The overll stoichiometric rection for these four steps cn be written s: 2C5H10O5+ C3H6O + 12H2 C13H H2O kg C H O kg C H O kg H kg C H 92 kg H O Theoreticlly, 1.0 kg of tridecne cn be produced from the following rw mterils: 1.6 kg xylose (or xylose oligomers), 0.3 kg of cetone nd 0.13 kg of H 2 (1) 2. Experimentl nd mterils 2.1 Mterils Hemicellulose extrct ws obtined from the University of Mine. In their process mixed hrdwood chips comprised primrily of mple (~50%) with lesser mounts of beech, birch nd poplr, obtined from Red Shield Pulp & Chemicls (Old Town, ME, USA), were extrcted with hot wter in custom-built rotting digester. Typiclly in ech btch, 7 kg of wood (on n oven-dry bsis) ws dded to the digester t liquor-to-wood rtio of 4 : 1. The extrction ws performed t mximum temperture of 160 C for trget H-fctor of 360 h. 24 Tble 1 shows the chemicl compositions of the hydrolyzed nd un-hydrolyzed hemicellulose extrct. The hemicellulose extrct ws hydrolyzed t ph 1.0 with sulfuric cid t 130 C for 30 min in n utoclve. 24 The feed used for our study ws un-hydrolyzed nd the xylose ws primrily in the form of oligomers. Tetrhydrofurn (THF, 99+%), cetone (histologicl grde), NOH (grnulr), NCl (grnulr), HCl (37 wt%) were ll purchsed from Fisher Scientific nd used s received. 2.2 Experimentl nd nlysis Acid hydrolysis nd xylose dehydrtion. The combined cid hydrolysis of xylose oligomers nd xylose dehydrtion were conducted in biphsic btch rector of 120 ml or 160 ml. The required mount of NCl ws first dded into the sugr solution t room temperture to sturte the queous phse. The resulting sugr solution nd THF were then mixed together in the rector, followed by the ddition of the required mount of HCl. The rector ws purged severl times with helium to remove ir nd chrged to 220 psig helium pressure. The rector wsthenhetedto160 C with vigorous stirring nd held for different times rnging from 5 to 60 min. Finlly, the rector ws immeditely quenched in n ice bth to stop the rection. The products were nlyzed by using Shimdzu high-performnce liquid chromtogrph (HPLC) equipped with both U nd RI detectors. Xylose content ws detected with n RI detector (RID-10A, cell temperture 30 C). Product of furfurl ws detected with U-vis detector (SPD-20A) t wvelength of 254 nm. The column used ws Biord C Aminex HPX- 87H sugr column nd the column oven temperture ws held constnt t 30 C. Isocrtic elution mode ws used with the mobile phse of M H 2 SO 4 t flow rte of 0.6 ml/min Aldol condenstion. Aldol condenstion of furfurl with cetone ws conducted t tmospheric pressure in biphsic ctlytic system consisting of rective queous phse nd n orgnic extrcting phse. The orgnic phse ws creted by dding cetone to the solution of furfurl in THF produced This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,

6 Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 from the biphsic dehydrtion, nd the queous phse consisted of wt% NOH nd sturted NCl (if used). In order to mke F-Ac-F dimer, the molr rtio of furfurl to cetone ws kept constnt s 2. The mixture ws stirred vigorously t tempertures rnging from 25 Cto80 C for 24 h nd the ldol dducts in THF were obtined through the liquid liquid seprtion. The experiments were crried out in different rector sizes rnging from 50 ml to 500 ml. The products of F-Ac-F nd F- Ac were nlyzed by using HPLC with SPD-20 A U (330 nm) detector, nd reverse-phse C-18 column from Agilent ws used. Grdient elution mode ws used with the mobile phse of methnol wter mixture (volume rtio of methnol to wter = 3 : 1) nd pure methnol t totl flow rte of 0.8 ml/min Low-temperture hydrogention. The effluent of the ldol rector ws subsequently hydrogented in btch rector of 120 ml t C nd 800 psig with 5 wt% Ru/C powder ctlyst (Strem Chemicls). Hydrogen ws consumed during the rection nd more ws supplied from time to time to mintin the pressure. The products were nlyzed by Shimdzu gs chromtogrph (GC) (model 2010). A flme ioniztion detector (FID) ws used to quntify the hydrogention products. The GC MS equipped with Restek Rtx-MS (Ctlog No ) column ws used to identify the hydrogention products. The hydrogented products seprted by column chromtogrphy nd verified by using 1 Hnd 13 C NMR were used s stndrd compounds for clibrtion. For GC MS, ultr-high purity helium ws used s the crrier gs, nd the tempertures of injector nd detector were both set t 240 C. The GC oven ws progrmmed with following sequence: hold t 35 C for 5 min, rmp to 240 Ct10 C/min nd hold t 240 C for 5 min Hydrodeoxygention. The hydrogented dimer in THF ws subject to the hydrodeoxygention in continuous plug flow bed rector with 4 wt% Pt/Al 2 O 3 SiO 2 ctlyst. The ctlyst ws prepred by using the incipient wetness method. The required mount of tetrminepltinum(ii) nitrte (Strem Chemicls) in deionized wter ws dded dropwise to the siliclumin powder (SiO 2 -to-al 2 O 3 rtio = 4, Dvison SIAL 3125) with continuous mixing. The s-mde ctlyst ws first dried in n oven t 80 C for 8 h, then clcined in ir t flow rte of 200 cm 3 /min with the following temperture regime: room temperture to 260 C for 3 h, hold t 260 C for 2 h. The obtined ctlyst ws reduced in H 2 t flow rte of 200 cm 3 /min with the following temperture regime: room temperture to 450 C t 50 C/h, hold t 450 C for 2 h. The gseous products were nlyzed by n online Shimdzu GC (model 2010) equipped with FID nd TCD detectors, nd the liquid products were nlyzed by GC MS. The C 1 C 6 lknes in the gs product were quntified by using FID detector. The ctlyst ws pcked in the 1 / 4 stinless steel tubing with glss wool on both sides. Feed of the hydrogented dimer (H-FAF) ws pumped to the rector by using JASCO PU980 HPLC pump nd hydrogen ws supplied from the bottom. The bckpressure regultor ws used to mintin the system t the desired pressures. 2.3 Clcultions In the biphsic dehydrtion step, xylose conversion nd furfurl selectivity were clculted s shown below. Assuming tht the xylose solubility in THF is negligible, the xylose concentrtion (mmol/ml), [Xylose], represents the queous phse concentrtion. [ Xylose ] [ Xylose ] feed feed q. q. Conversion = 100% (2) [ Xylose] feed f eed [ Furfurl ] +[ Furfurl ] Selectivity = [ Xylose] [ Xylose] q. q. org. org. feed feed q. q. 100% (3) In the biphsic ldol condenstion step, furfurl conversion nd F-Ac-F dimer selectivity were clculted s given below. Given the low solubtility of F-Ac-F in wter (s shown in Tble S1,36 39 ), the F-Ac-F dimer concentrtion (mmol/ml) represents the orgnic phse concentrtion. [ Furfurl ] Furfurl Conversion = [ ] [ Furfurl] feed feed org. org. feed feed [ F-Ac-F] org. org. Selectivity = [ Furfurl] [ Furfurl] feed feed org. org. 100% (4) 100% (5) In the low-temperture hydrogention step, F-Ac-F dimer conversion nd hydrogented F-Ac-F (H-FAFs) selectivity were clculted s given below. F-Ac-F F-Ac-F Conversion = [ ] [ ] [ F-Ac-F] feed feed finl finl feed feed [ H-FAFs] finl finl Selectivity = [ F-Ac-F] [ F-Ac-F] feed feed finl finl 100% (6) 100% (7) For the bove three processes, represents the corresponding phse volume (ml), nd the rection yield is defined s conversion selectivity. In the hydrodeoxygention process, crbon lkne yield = (totl moles of crbon toms in lkne products)/(totl moles of crbon toms in the feed of H-dimer) 100%. 3. Results 3.1 Acid hydrolysis nd xylose dehydrtion The combined cid hydrolysis of xylose oligomers nd xylose dehydrtion were conducted t 160 C nd 220 psig in biphsic rector using wter THF s solvent with HCl s the ctlyst. We sturted the hemicellulose extrct with NCl by dding 20 g NCl to 100 g hemicellulose extrct. 13 This sturtion ws done to decrese the solubility of THF in the queous strem. The results for dehydrtion of hemicellulose extrct re summrized in Tble 2. Initilly, the molr rtio of HCl to xylose ws vried (Tble 2, Runs 1 4) to study the effect of HCl mount on furfurl selectivity. These experiments were conducted for 60 min by keeping the mss rtio of orgnic to queous phse t 2 : 1. As cn be seen, ll xylose ws lmost completely converted fter 60 min of rection. The furfurl selectivity increses from 12.6% to 80.7% s the HCl/xylose molr rtio increses from 1936 Green Chem., 2010, 12, This journl is The Royl Society of Chemistry 2010

7 Tble 2 Furfurl production by the biphsic dehydrtion of queous sugr solutions. Feeds for rections were hemicellulose extrct (H-extrct) contining 2.1 wt% xylose nd its oligomers, except Run 11 which ws n queous solution contining 3.6 wt% pure xylose. Equl mount by weight of queous solution ws used nd the rection ws controlled t 160 C with the use of THF s the orgnic solvent. The NCl content ws kept t 20 wt% (reltive to the mount of hemicellulose extrct) for Runs 1 10, nd 35 wt% for Run 11, respectively Run # Btch size Rection (ml) Sugr solution M org. /M q. HCl/xylose b time (min) Xylose conversion (%) Furfurl selectivity (%) Furfurl yield (%) Downloded by University of Msschusetts - Amherst on 28 Mrch H-extrct H-extrct H-extrct H-extrct H-extrct H-extrct H-extrct H-extrct H-extrct H-extrct Xylose Mss rtio of orgnic phse to queous phse. b Molr rtio of HCl to xylose. Tble 3 Aldol condenstion of furfurl with cetone in biphsic btch rector. All runs were conducted for bout 24 h t tmospheric pressure. The molr rtio of furfurl to cetone ws kept constnt t 2 Run # Btch size (ml) NCl (wt%) Feed furfurl (wt%) M org. /M q. NOH/furfurl T ( C) b Furfurl conversion (%) F-Ac yield (%) F-Ac-F yield (%) Mss rtio of orgnic to queous phse. The orgnic phse consists of furfurl, THF nd cetone, nd the queous phse consists of wter, NOH nd NCl (if used). b Molr rtio of NOH to furfurl. 0.6to2.4.Thissuggestsththighcidconcentrtionisnecessry to obtin high selectivity of furfurl. Similr effects were reported using 5 : 5 (w/w) wter DMSO mixture nd 7 : 3 (w/w) MIBK 2-butnol s the orgnic phse. 22 Further incresing the rtio of HCl to xylose to 3 : 1 improves the selectivity by only 3%. 27,32 In pure wter, the dehydrtion of xylose yields low selectivity of only 47% due to the presence of side rections including frgmenttion, condenstion, nd resinifiction. 27 The ddition of THF to the queous phse improves the selectivity for furfurl by extrcting out the furfurl before it cn undergo undesired rections. The effect of the orgnic-to-queous mss rtio on the dehydrtion performnce ws investigted by keeping ll other conditions constnt s shown in Tble 2 (Runs 2 nd 5 7). As we cn see from these runs, the furfurl selectivity incresed from 60% to 79% s the orgnic-to-queous mss rtio incresed from 0.67 to 1. Further incresing the mss rtio to 3 : 1 cused slight increse of furfurl selectivity up to 81.7%. Runs 4 nd 8 10 in Tble 2 demonstrte the effect of rection time on the xylose conversion, furfurl selectivity nd yield. A decrese of rection time increses the furfurl yield. For comprison, Run 11 shows the result of dehydrtion of pure xylose, nd the 90% yield for furfurl could be obtined even t lower HCl/xylose rtio of 0.6. This suggests tht higher cid concentrtion is needed for furfurl production from the hemicellulose extrct thn from pure xylose, possibly becuse high cid conditions re fvorble for the hydrolysis of xylose oligomers to form xylose. 3.2 Aldol condenstion The results for ldol condenstion of furfurl with cetone in btch rector re summrized in Tble 3. For ll runs, the conversions of furfurl were lmost complete. The effect of temperture on the selectivity of the ldol products ws studied using 13 wt% furfurl in THF with stoichiometric mount of cetone (molr rtio of furfurl to cetone = 2) dded to the orgnic phse s shown in Runs 1 3 of Tble 3. The rection ws conducted in the presence of sturted NCl in 50 ml rector (NOH: furfurl molr rtio = 2.3 : 1, M org. :M q. = 1 : 1). The selectivity for both F-Ac nd F-Ac- F decreses from 3.1% to 1.8% nd from 93.5% to 69.8%, respectively, s the rection temperture increses from 25 Cto 80 C. However, the distribution of F-Ac nd F-Ac-F products hs little vrition with temperture. The lower selectivity to F-Ac-F observed for higher rection tempertures (50 Cnd 80 C) ws probbly cused by the degrdtion of F-Ac-F due to its thermlly instbility. Aldol condenstion with nd without dding NCl into the rective queous phse ws performed This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,

8 Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 in 100 ml biphsic rector (Runs 4 7, Tble 3). It ws found tht higher selectivity for F-Ac-F could be produced without NCl. Incresing the molr rtio of NOH to furfurl not only improves the totl condenste yields, but lso increses the selectivity for F-Ac-F. Runs 4, 6 nd 8 show the effect of NOH/furfurl molr rtio on the product selectivity without dding NCl. The results show tht the selectivity for F-Ac-F grdully increses from 61.8% to 92.2% s the NOH/furfurl rtio increses from 0.13% to 0.48%. Further optimiztion of the rection shows tht selectivity of 96.2% for F-Ac-F nd 0.002% for F-Ac re chieved in 200 ml rector from the ldol condenstion of 36.8 wt% furfurl in THF with cetone (Run 9, Tble 3), in which the mss rtio of orgnic to queous phse is 5.1 : 1 nd the NOH/furfurl rtio is 0.37 : 1. This suggests tht both the orgnic-to-queous mss rtio nd the NOH/furfurl molr rtio hve importnt influence on the selectivity nd distribution of finl ldol dducts. Scle-up rections were performed in 500 ml rector using the sme rection conditions s tht in Run 9 with rection yields of 90.9% for F-Ac-F nd 0.04% for F-Ac, respectively (Run 10, Tble 3). Controlling the rection conditions in the ldol condenstion step cn be used to tune the ultimte desired composition of C 8 or C 13 lknes. To summrize, the optimized rection system not only llows the production of trgeted F-Ac-F t high yields by using higher concentrtion of furfurl s the feed, lower mounts of NOH, nd lower mounts of the queous phse thn those previously reported by Dumesic nd co-workers, 34 but lso elimintes the use of NCl, thereby reducing the product cost. Fig. 2 shows the disppernce of furfurl nd the selectivity for F-Ac nd F-Ac-F s function of time for Run 1. The conversion of furfurl nd cetone (not shown here) ws lmost complete t 35 min fter strting the rection. The selectivity for F-Ac decreses from 11.3% to 3.5% s time increses from 35 min to 20 h, while the selectivity for F-Ac-F grdully increses with time from 42.7% to finl 93.5%, suggesting other rections re involved besides the ldol condenstion of furfurl with cetone. In the HPLC chromtogrm, n unidentified pek in betweenf-acndf-ac-fislwyspresentforllrection conditions strting from the first minutes of the synthesis. This pek grdully decreses s time increses, suggesting tht the intermedite products such s b-hydroxy crbonyl compounds re formed during the ldol condenstion rection. In the HPLC chromtogrms, the intermedite product hs retention time inbetween tht of F-Ac nd F-Ac-F, nd there re no other products observed from either HPLC or GC MS. This suggests tht the decomposition of the intermedite product to F-Ac-F (nd not other products) is the most probble route, in greement with the previous report by Fkhfkh et l Low-temperture hydrogention The F-Ac-F dimer in THF produced from the ldol condenstion ws subsequently hydro-treted in btch rector to sturte the three kinds of double bonds (lkene C C, furn C C nd ketone C O bonds). Fig. 3 illustrtes the influence of rection temperture nd mss of ctlyst on the conversion of F-Ac-F. The results show tht the hydrogention rte increses with temperture. For exmple, F-Ac-F ws 91% converted in 25 min t 125 C, compred with 81.4% conversion in 32 min t 110 C. In ddition, the use of high mss rtio of Ru/C to F-Ac-F cn speed up the conversion of F-Ac-F. The hydrogention product consists of mixture of hydrogented dimers with different degrees of hydrogention, indicting there exists multi-step hydrogention of double bonds of F-Ac-F. Three hydrogented products were identified during hydrogention rections the spiro, ketone nd lcohol form of the dimer, s shown in Fig. 4. The C C double bonds in the side chin re hydrogented first to form the intermedite furn ketone, followed by three pthwys to form the spiro, ketone nd lcohol H-dimers s suggested by Mtykubov et l. 40 The intermedite furn ketone nd intermedite furn lcohol were not observed in the present study, most likely becuse these compounds were immeditely consumed. 40 The spiro nd lcohol H-dimers re fully hydrogented, nd the ketone H-dimer contins only one sturted crbonyl bond. Fig. 5 shows the F-Ac-F disppernce nd selectivity for hydrogented dimers s function of time for typicl hydrogention run over Ru/C t 110 C nd 800 psig. As we cn Fig. 2 Furfurl disppernce nd selectivity for monomer (F-Ac) nd dimer (F-Ac-F) s function of time. The experiment ws conducted in 50 ml btch rector t 25 C nd tmospheric pressure. The feed concentrtion of furfurl in THF ws 13 wt% nd NCl ws dded to sturte the rective queous phse. Molr rtio of NOH to furfurl = 2.3, mss rtio of orgnic to queous phse = 1. Fig. 3 Hydrogention of F-Ac-F dimer s function of time nd ctlyst concentrtion. The rections were conducted in btch rector t 800 psig nd vrious tempertures. The feed concentrtion ws 11.5 wt% dimer in THF Green Chem., 2010, 12, This journl is The Royl Society of Chemistry 2010

9 Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 Fig. 4 Rection pthwys for hydrogention of F-Ac-F dimer to hydrogented H-dimers t 110 Cnd800psigwith5wt%Ru/C powder ctlyst. see, three types of hydrogented dimers could be identified within 10 min from strting the rection. The selectivity of ketone H- dimer quickly reches mximum, followed by continuous decrese to zero concentrtion t 120 min. The selectivity of spiro H-dimer grdully increses s time increses, nd reches mximum t 120 min, followed by slight decrese with time. The selectivity of lcohol H-dimer shows continuous increse s time increses. The finl products, consisting of minly spiro nd lcohol dimers were used to mke lknes in the next step. with 4 wt% Pt/SiO 2 Al 2 O 3 ctlyst. Fig. 6 shows the n-lkne distributions from hydrodeoxygention of H-dimers t LHS of 1.1 h -1. The totl crbon yield for jet nd diesel fuel rnge lknes (C 8 C 13 ) ws 91%, with tridecne nd dodecne being the primry products, ech of which ccounts for 72.6% nd 15.6%, respectively. Bsed on GC MS dt, the liquid phse lso contins very smll mounts of two other lknes lrger thn C 13, viz., 6,9-dimethyltetrdecne nd 2,6-dimethyldodecne. The H-dimer conversion ws 100% under the current conditions, nd the Pt/SiO 2 Al 2 O 3 did not undergo dectivtion even fter 120 h testing. In the effluent gs phse, only C 1 C 6 lknes were observed, nd no CO or CO 2 ws detected in the products. In the liquid phse, other thn THF nd lknes, there were some other orgnic oxygentes identified by GC MS, including butnol, butyl propyl ether, butnoic cid, nd furn nd its derivtives, which re most likely byproducts from THF. Fig. 6 Crbon lkne yields for the hydrodeoxygention of H-FAF t 260 C nd 900 psig with 4 wt% Pt/SiO 2 Al 2 O 3 ctlyst using LHS of 1.1 h -1. The feed contins 7 wt% hydrogented dimers. Fig. 7 shows the effect of spce velocity on the crbon n- lkne (C 11 C 13 ) yields for hydrodeoxygention of H-dimers. At LHS of 1.1 h -1, ll lkne yields rech their mximum vlues. Incresing the LHS from 1.1 h -1 to 2.5 h -1 decreses the tridecne yield from 76.2% to 28.9% due to the low conversion of H-dimers. Fig. 5 F-Ac-F disppernce nd selectivity for spiro H-dimer, ketone H-dimer, nd lcohol H-dimer s function of time. The rection ws conducted t 110 C nd 800 psig with 5 wt% Ru/C ctlyst. The feed solution contins 11.5 wt% F-Ac-F dimer in THF. 3.4 Hydrodeoxygention After low-temperture hydrogention, the effluent contining mixed hydrogented dimers nd THF ws sent to continuous plug flow bed rector to mke lknes t 260 C nd 900 psig 4. Discussion Our experimentl results hve demonstrted the technologicl fesibility of obtining high yields of jet nd diesel fuel rnge lknes from hemicellulose-derived queous solutions. Tble 4 lists the current experimentl nd future trget yields for ech step for this process. The overll experimentlly obtined yield of 76% for jet fuel rnge lknes corresponds to weight-percent yield of 0.46 kg of lknes per kg of xylose (monomer nd oligomers) in the hemicellulose extrct. The theoreticl yield for this process is 0.61 kg of lknes per kg of xylose (monomer nd oligomers) in the hemicellulose extrct. Currently, the lowyielding steps re dehydrtion nd hydrodeoxygention. For LHS is defined s the volumetric flow rte of feed solution divided by the volume of ctlyst. This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,

10 Tble 4 Current yields nd future trget yields for the production of jet nd diesel fuel rnge lknes from the hemicellulose extrct Yield (%) Dehydrtion Aldol condenstion Hydrogention Hydrodeoxygention Overll Current Future The furfurl yield of 81% is used in the cse of M org. /M q. = 1 for economic nlysis. Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 Fig. 7 Effect of LHS on lkne (C 11 C 13 ) yields for hydrodeoxygention of H-FAF (spiro dimer nd lcohol dimer). The rections were conducted in continuous plug flow rector over Pt/SiO 2 Al 2 O 3 t 260 C nd 900 psi. The feed contins 5 15 wt% hydrogented dimer nd ws prepred by hydrogention of F-Ac-F dimer in THF t 110 C nd800psigfor600minwith5wt%ru/cctlyst. thedehydrtionstep,wehvebeenbletoobtinyieldof 90% with model xylose solutions, s shown in Tble 2. The kinetic model for the dehydrtion of xylose in biphsic rector suggests tht yield of 95% cn be chieved with MIBK wter s solvent t elevted tempertures nd shorter residence time. 41 Therefore it should be possible to obtin yields close to 95% for this process by further optimizing the rection system. Yields higher thn 95% re very chllenging due to the undesired decomposition nd polymeriztion rections. The yield for the hydrodeoxygention step could lso be improved from 91% to 95% with improvements in the ctlysts nd rector design. We predict tht the overll yield for jet nd diesel fuel rnge lknes could be incresed up to 88% (s shown in Tble 4) with these modest process improvements. The stright lknes produced in our process cn be further upgrded vi the hydroisomeriztion process to form brnched lknes. The stright nd brnched lknes together cn either be directly sold s chemicls or liquid fuels, or sent to refinery s dditives to mke the desired jet nd diesel fuels by blending with other hydrocrbons. Currently the lterntive pproch to the synthesis of stright nd brnched lknes for synthetic jet nd diesel fuels is the Fischer Tropsch process, using synthesis gs derived from nturl gs. 42 As such, our process provides nother wy to mke jet nd diesel fuels rnge lknes from wste hemicellulose-derived solutions. Next we will show how our four-step process cn be integrted for production plnt, nd preliminry economic nlysis for our process is performed to evlute the product cost. 4.1 Integrted process flow nd mterils blnce Fig. 8 shows process flow digrm nd Tble S2 shows the mteril blnces for mking jet nd diesel fuel rnge lknes from hemicellulose extrcts. The mteril blnce in Tble S2 Fig. 8 Process flow digrm for the production of jet fuel rnge lknes from hemicellulose-derived queous solutions. Process strem key: wt% hemicellulose extrct; 2. NCl; wt% HCl; 4. THF; 5. Furfurl + THF + q. phse; 6. Aq. phse, 7. Furfurl + THF; 8. THF; 9. Furfurl + THF; 10. Acetone; wt% NOH; 12. F-Ac-F + THF + q. phse; 13. Aq. phse; 14. F-Ac-F + THF; 15,19,20,21. Recycling strems of H 2 ; 16. H-FAF; 17,18. Input H 2 ; 22. Fresh chrge of H 2 ; 23. Tridecne + THF + q. phse; 24. Aq. phse; 25. Tridecne; 26. THF Green Chem., 2010, 12, This journl is The Royl Society of Chemistry 2010

11 Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 ssumes 100% yield for ech step. The hemicellulose extrct (Strem 1), solid NCl (Strem 2), concentrted 37 wt% HCl solution (Strem 3) nd the NCl-pretreted THF (Strem 4) re co-fed to the first biphsic rector (R-01) which is ssumed to be CSTR-type rector. Equl weights of orgnic nd queous phse re used here. The NCl content reltive to the sugr solution is 20 wt% s shown in Tble S2. In this rector, furfurl is produced vi the biphsic dehydrtion of xylose t 160 C nd 220 psig with residence time of 5 min. These rection conditions were obtined from our experimentl results s shown in Tble 2. The rector effluent (Strem 5) is then sent to Decnter 1 where THF nd furfurl (Strem 7) re seprted from the queous phse (Strem 6). The queous phse could be further processed to recover NCl, HCl, lctic cid, formic cid nd cetic cid. 8,13,51 After liquid liquid split, the orgnic phse (Strem 7) is sent to the Flsh to concentrte furfurl to 37 wt% (Strem 9) by removing the mjority (96%) of THF. The removed THF (Strem 8) is recycled bck to the first rector (R-01). The concentrted furfurl in THF (Strem 9), 26 wt% NOH solution (Strem 11) nd cetone (Strem 10) re co-fed into the second well-mixed rector (R-02), where the F-Ac-F dimer is produced vi the ldol condenstion t room temperture nd tmospheric pressure for residence time of 24 h. These re the sme rection conditions used for the ldol condenstion s shown in Tble 3 This rector effluent contins minly the orgnic phse (THF nd F-Ac-F dimer produced) nd smll mount of queous phse. The queous phse (Strem 13) is removed vi Decnter 2 nd could be further processed to recover NOH, nd the orgnic phse (Strem 14) together with H 2 (Strem 17) re fed to the hydrogention rector (R-03) where the F-Ac-F dimer is hydrogented to form H-FAF t 110 Cnd 800 psig with 5 wt% Ru/C ctlyst s described in Section 2.2. The H-FAF in THF (Strem 16) together with H 2 (Strem 18) re finlly fed to the hydrodeoxygention rector (R-04) where the production of jet nd diesel fuel rnge lknes tke plce t 260 C nd 900 psig with 4 wt% Pt/Al 2 O 3 -SiO 2 ctlyst. In the lst two steps, H 2 is fed by using compressors (Compressor 1 nd Compressor 2) nd rtio of excess H 2 to fresh-chrging H 2 of 2 is used. The effluent from the hydrodeoxygention rector (Strem 23) is sent to Decnter 3 where the remining THF is vporized nd recycled bck to R-01 (Strem 26), wter (Strem 24) is removed vi liquid liquid split, nd jet nd diesel fuel rnge lknes (Strem 25) re obtined from the orgnic phse. For ll decnters, the projected temperture nd pressure re 25 C nd 14.7 psi. 4.2 Preliminry economic nlysis Rw mterils cost. The rw mterils cost is clculted bsed on the current yields nd future trget yields s shown in Tble 4. Preliminry nlysis by reserchers t the Univeristy of Mine shows tht the estimted cost of xylose derived from pre-processing extrcts t n integrted forest products refinery co-locted t hrdwood Krft mill or biomss boiler is on the order of $0.15/kg on dry bsis. This cost ccounts for sugr heting vlue lost by the host mill, the costs of extrcting nd concentrting the extrct, nd the costs nd revenue ssocited with recovering cetic cid s co-product. In our clcultions the price of $0.1/kg dry xylose is used s thebsecse.h 2 is employed from n externl source nd its purchse price cn vry significntly depending on the loction of new plnt to be built. The price of H 2 considered in our clcultion is bsed on report relesed by the Ntionl Renewble Energy Lbortory. 44 Assuming tht the new plnt is built in plce close to H 2 production plnt, the H 2 price cn be s low s $1.0/kg. The cetone t the time of this nlysis is vilble for $0.7/kg. As result, for the bse cse the overll rw mterils cost is $1.79/gl nd $1.60/gl jet nd diesel fuel rnge lknes bsed on current yields nd future trget yields, respectively. For the bse cse, H 2 costs $0.41/gl nd $0.39/gl, xylose costs $0.66/gl nd $0.53/gl nd cetone costs $0.72/gl nd $0.68/gl for current yields nd future trget yields, respectively. The cost of cetone represents pproximtely 41% of the rw mterils cost. It should be noted tht for this economic nlysis we re not including the cost of NCl or ny disposl costs; the NCl is considered to be recycled in our process Instlled equipment cost nd ssocited utility cost. Tble 5 shows summry of instlled equipment cost nd ssocited utility cost for three different plnt cpcities bsed on the current yields nd future trget yields. The cost for instlled equipment nd ssocited utility re clculted bsed on the cost correltions described by J. M. Dougls. 43 Some equipment, such s pumps nd het exchngers, re not included nd will be dded in our future detiled nlysis when more detiled informtion is vilble. The instlled equipment cost for ll rectors lso includes the ctlyst cost. The costs of Ru nd Pt we used in R-03 nd R-04 re estimted from the online mrket vlue It should be noted tht the costs for HCl nd NOH we used in R-01 nd R-02 re not included for this economic nlysis. The totl instlled equipment cost is M$1.11, M$5.61 nd M$44.30 for 0.5 Mgl/yr, 5 Mgl/yr nd 50 Mgl/yr plnt cpcities bsed on current yields, respectively. The totl equipment cost cn be reduced by 8.2%, 10.3% nd 15.0% for 0.5 Mgl/yr, 5 Mgl/yr nd 50 Mgl/yr plnt cpcities bsed on the future trget yields, respectively. The most expensive piece of equipment in this process is the cost of the rector for the ldol condenstion step, which ccounts for roughly 50% of the equipment cost. This high cost is due to the long residence time in this rector. This suggests the cost could be reduced by operting t lower residence time. The utility cost consists of the electricity cost for compressors nd the stem cost for R-01, Flsh nd Decnter 3. Bsic het integrtion is pplied for R-01, Flsh nd possible Decnter 3. Het relesed by cooling the output strem of R-01 cn be used to supply the energy required for the Flsh nd possible Decnter 3. The ltent het of THF vpor strems from Flsh nd Decnter 3 cn be used to prehet the input xylose solution of R-01. We my lso need heting supplies for R-03 nd R-04; however, for this economic nlysis we re ignoring these costs. These costs re most likely smll becuse of the low flows, the low concentrtion of wter nd the fct tht no phse chnge is occurring in the rector. As shown in Tble 5, the totl utility costs increse linerly from M$0.39 to M$3.85 to M$38.52 when the plnt cpcity increses from 0.5 Mgl/yr to 5 Mgl/yr to 50 Mgl/yr. The This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,

12 Tble 5 Summry of equipment nd utility costs of different process scles clculted bsed on the current yield (outside the prenthesis) nd future yield trgets (inside the prenthesis), respectively (4th qurter 2007) 0.5 (Mgl/yr) 5 (Mgl/yr) 50 (Mgl/yr) Equipment Instlltion cost (k$) Associted utility cost (k$/yr) Instlltion cost (k$) Associted utility Associted utility cost (k$/yr) Instlltion Cost (k$) cost (k$/yr) Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 R-01 b 134 (134) 377 (295) 490 (416) 3767 (2947) 2543 (2311) (29 470) R (432) 2668 (2422) (20 010) R (80) 595 (526) 5047 (4359) R (80) 601 (531) 5106 (4414) Decnter 1 75 (75) 318 (274) 1937 (1422) Decnter 2 10 (10) 53 (35) 160 (160) Decnter 3 c 5 (5) Integrted 19 (19) Integrted 87 (70) Integrted Flsh c 53 (53) Integrted 195 (160) Integrted 1049 (711) Integrted Compressor 1 d 54 (54) 1 (1) 96 (96) 7 (7) 559 (538) 74 (71) Compressor 2 d,e 96 (96) 8 (7) 580 (554) 77 (73) 3798 (3657) 766 (734) Totl 1110 (1019) 386 (303) 5614 (5033) 3851 (3027) (37 651) (30 275) The costs for instlled equipment nd ssocited utility re clculted bsed on the cost correltions described by J. M. Dougls. 43 b Assuming (1) the temperture of the feed sugr solution is 25 C, (2) the het relesed by condensing THF vpor strem is recycled bck to pre-het the sugr solution, (3) the temperture of recycled THF is 65 C, nd (4) the cost of 120 psig stem is 4.4 US$ per 1000 lb. c Heting energy is supplied by the het relesed from cooling the output strem of R-01. d Assuming (1) the pressure drop cross the rectors is 30 psi, (2) excess H 2 is twice s much s the stoichiometric mount, (2) process opertion time s 8150 h/yr nd (3) electricity cost is $/kwh (US ntionl verge electricity price for industry section in 2007). e Assuming tht H 2 comes out of the pipeline with pressure of 340 psi. 44 totl utility costs cn be reduced by 21.5% for ll three cpcities if the yield improves to the future trget yields. Among the utility costs, it is interesting to note tht R-01 ccounts for bout 98% of totl utility cost for ll three plnt cpcities due to the low concentrtion of sugr solution treted in R-01. As discussed below, the totl utility cost cn decrese significntly if high concentrtion of sugr solution is used s the feed to R Product cost. Bsed on rw mterils cost, utility cost nd instlled equipment cost, we clculted the totl nnul product cost using the following eqution: 43 Totl nnul product cost ($/yr) = (rw mterils cost + utility cost) (instlled equipment cost) (lbor cost) + generl expenses In this eqution, it is ssumed tht generl expenses including sle, dministrtion, reserch nd engineering re bout 2.5% of totl revenue. Fig. 9 shows the clculted unit production cost s function of production cpcity for current yields nd future trget yields. For the production cpcity s low s 0.5 Mgl/yr, the unit production cost is estimted to be $4.39/gl nd $4.01/gl for current yields nd future trget yields, respectively. The unit production cost decreses shrply s production cpcity increses up to 5 Mgl/yr ($3.17/gl nd $2.79/gl for current yields nd future trget yields, respectively). Further increse in the production cpcity results in less drmtic decrese in the unit product cost, which pproches $2.92/gl nd $2.54/gl, respectively, s the production cpcity pproches 50 Mgl/yr. The contribution (%) of the rw mterils cost in the finl product cost increses from 44.6% to 63.0% s production cpcity increses from 0.5 Mgl/yr to 50 Mgl/yr Sensitivity nlysis. A sensitivity nlysis ws performed to help identify how cost could be decresed in the future, nd where to focus future reserch efforts. The cost of the rw mterils is significnt prt of the cost, nd finding Fig. 9 Unit production cost s function of production cpcity bsed on the current nd future trget yields. We ssume tht (1) the price for xylose, cetone nd H 2 is $0.1/kg, $0.7/kg, nd $1.0/kg, respectively, (2) there re three shifts with ll processes, 1 opertor per shift, 2 opertors per shift nd 4 opertors per shift for the process with 0.5, 5 nd 50 Mgl/yr, respectively. Lbor cost = 10 5 $/opertor, nd (3) in the revenue clcultion, the selling price of product is $3/gl. cheper source of rw mterils cn significntly reduce the product cost. Tble 6 summrizes the sensitivity nlysis of rw mterils cost. As the xylose price doubles, the rw mterils cost will increse by 36.9% nd by 33.1% for current yields nd future trget yields, respectively. As the price of H 2 doubles, the rw mterils cost will increse by 22.9% nd by 24.4% for the current yields nd future trget yields, respectively. Compred to H 2 nd xylose, the cetone price hs the most significnt impct on rw mterils cost. As the cetone cost doubles, the rw mterils cost increses by 40.2% nd 42.5% bsed on current yields nd future trget of yields, respectively. The mjority of the utility cost is ssocited with the het required for R-01 which is used to het the sugr solution nd THF to the rection temperture of 160 Csshownin Tble 5. If the feed xylose concentrtion in the hemicellulose 1942 Green Chem., 2010, 12, This journl is The Royl Society of Chemistry 2010

13 Tble 6 Sensitivity nlysis of rw mterils cost on prices of xylose, H 2 nd cetone. The itlicised dt refer to the cost for the bse cse Feedstocks Price ($/kg) Rw Mterils Cost w/ Current Yield ($/gl) Rw Mterils Cost w/ Future Yield trget ($/gl) Downloded by University of Msschusetts - Amherst on 28 Mrch 2012 Xylose b H Acetone c With cetone prices s $0.7/kg, H 2 price s $1.0/kg. b With cetone price s $0.7/kg, xylose price s $0.1/kg. c With H 2 price s $1/kg, xylose price s $0.1/kg. extrct increses, the heting requirement for R-01 decreses, consequently leding to the decrese of the utility cost for R-01. The sizes of R-01 nd Decnter 1 lso decrese with incresing xylose concentrtion, leding to lower instlled equipment cost. Therefore, incresing the xylose concentrtion in the hemicellulose extrct cn significntly decrese both the instlled instrument cost nd the utility cost s shown in Tble 7. As the xylose concentrtion increses from 3 wt% to 10 wt%, the instlled cost nd utility cost decrese by 39.5% nd by 68.1%, respectively, for plnt cpcity of 50 Mgl/yr. Fig. 10 shows the unit product cost s function of both the production cpcity nd the xylose concentrtion in the hemicellulose extrct ssuming the future yield scenrio. Incresing the feed xylose concentrtion cn significntly decrese the unit product cost. Compred to the 3 wt% xylose cse, the unit product cost for 10 wt% xylose cse cn further decrese by 18.9% from $2.54/gl to $2.06/gl for the production cpcity of 50 Mgl/yr. The price of $2.06/gl is ctully lower thn the current US mrket jet fuel price. 47 minimum vlues. Incresing the orgnic-to-queous mss rtio from 1 to 2 is fvorble to increse the yield of furfurl (from 81% to 87%), but cuses the unit product cost to increse due to incresed instlled nd utility costs. Decresing the mss rtio to 0.67 lso increses the unit product cost resulting from the significnt drop of furfurl yield (from 81% to 62%). The mss rtio of 1 should be used in order to minimize the product cost. Fig. 11 Effect of the orgnic-to-queous mss rtio (M org. /M q. )in the biphsic dehydrtion step on the unit product cost t different production cpcities. The dt were clculted bsed on the current yields ssuming the xylose concentrtion in the hemicellulose extrct is 3wt%. Fig. 10 The totl product cost vries s function of production cpcity nd feed xylose concentrtion bsed on the future yields. The ssumptions re the sme s those in Fig. 9. Modifying the orgnic-to-queous mss rtio in R-01 does not significntly chnge the product cost, s shown in Fig. 11. This nlysis ws performed bsed on current yields ssuming tht the 3 wt% xylose in the hemicellulose extrct is used s the feed. At the mss rtio of 1, ll unit product costs rech their A sensitivity nlysis of the Pt nd Ru ctlyst cost for R-03 nd R-04 on the unit product cost ws lso conducted. This result suggests tht the contribution of the ctlyst cost to the unit product cost is below 1% for ll cses, suggesting tht the ctlyst cost of Ru nd Pt is not mjor fctor ffecting product cost. These results here suggest tht the most importnt vrible ffecting product costs is the cost of the rw mterils. Finding chep rw mteril is the top priority in mking this process commercil. Currently cetone is used s coupling gent, but in the future methods to form C C bonds directly from furfurl-derived molecules cn be developed The second most importnt vrible ffecting the product cost is finding high concentrtions of sugr solutions, s this significntly ffects the product cost. We should note here tht the sugr strems used in our process re derived from wood-processing industries This journl is The Royl Society of Chemistry 2010 Green Chem., 2010, 12,