【正文】 consequently there are no side reactions or byproducts and the hydrolysis can potentially be run with yields approaching 100% of theoretical [6]. Pretreatment is necessary to achieve reasonable rates and yields in the enzymic hydrolysis of biomass. To open up the lignocellulosic structure to wide microbial degradation, expensive energy demand ing pretreatment processes are required. In the pretreatment area, the reduction of power for milling is one of the technological improvements that will result in substantially lower ethanol production costs. Autohydrolysis steam explosion has generally been accepted as one of the most costeffective method for pretreating lignocellulosic biomass, since no addition of external catalyst is necessary[7
9].The most important variables in steamexplosion pretreatment are time, temperature and chip size. Generally, when larger chips are used, heat transfer problems may result in overcooking of the outside (with the associated formation of inhibitors) of the chip andinplete autohydrolysis of the interior[10]. Consequently, prior to steam explosion pretreatment, particle size has to be reduced, which requires significant amounts of energy. Another constraint for the autohy drolysis steam explosion is the low hemicellulosic sugars yield, and its negative impact on ethanol production economics. Research efforts have been concentrated on maximising cellulose recovery and have failed to recognise the importance of recovering the hemicellulosic ponent, which is of crucial importance to improve the overall economics of the cellulosic biomass to ethanol , it would be desirable to test innovative conditions to improve the economics of the pretreatment stage by reducing electrical power during the . Analytical methodsstage, and by optimising the pretreatment recovery of the hemicellulose ponent, as well as enhancing cellulose hydrolysis. The objective of this work was to evaluate the effect of particle size on the steamexplosion pretreatment of a lignocellulosic agricultural waste ().Cellulose recovery, enzymic hydrolysis effectiveness of the solid residue, and sugar position in the filtrate are presented for steamexplosion pretreatment using different particle sizes.雖然取得了相當(dāng)大的進(jìn)展技術(shù)轉(zhuǎn)制為木質(zhì)生物質(zhì)轉(zhuǎn)化為乙醇,實(shí)質(zhì)性的機(jī)會(huì)仍然存在以降低生產(chǎn)成本[4,5]。在預(yù)處理區(qū)、降低動(dòng)力銑是一個(gè)技術(shù)改進(jìn),將導(dǎo)致大幅降低乙醇生產(chǎn)成本。因此,蒸汽爆炸前預(yù)處理,粒子大小必須減少,這就需要大量的能源。分析方法階段,通過(guò)優(yōu)化預(yù)處理復(fù)蘇的半纖維素成分,以及提高纖維素的水解。原材料是磨使用實(shí)驗(yàn)室錘式粉碎機(jī)。以下參數(shù)進(jìn)行了調(diào)查:190210 8 c溫度和48分鐘停留時(shí)間。爆炸發(fā)生后,材料被發(fā)現(xiàn)在一個(gè)氣旋,濕材料冷卻到約40 8 c,然后過(guò)濾固體復(fù)蘇。 酶水解預(yù)處理后的水不溶性纖維是enzymically水解來(lái)確定maximumobtainable糖產(chǎn)量。)(IU)/ g襯底?？偺妓衔锉淮_定根據(jù)脈沖法[15]。結(jié)果與討論表1顯示了原材料的組成。這個(gè)%的原料,木糖被主要的糖(82%)。正如預(yù)期的那樣,蒸汽爆破預(yù)處理優(yōu)先攻擊了半纖維素成分。 有趣的是,我們注意到,在蒸汽爆破預(yù)處理、水溶性糖的比例是依賴于類(lèi)型的hemicellulosic糖。纖維素含量在62%和之間biomassvaried進(jìn)行預(yù)處理,根據(jù)嚴(yán)重程度的預(yù)處理。有增加半纖維素糖降解在更高的溫度和停留時(shí)間。一個(gè)重大的破壞得到木糖在210 8 c(大約40%)。 and (c) recovery of hemi cellulosic sugars in the . 1shows the cellulose recovery yield in the waterinsoluble fibre for all pretreatment conditions and chip size tested. Yield is expressed as glucose in the water insoluble fibre divided by the potential glucose in the raw material. As can be observed, the particle size has a significant influence on cellulose recovery. At larger particle size, more cellulose recovery was obtained. At 2
5 mm particle size cellulose recovery of 84% at 190 8C
4 min and 57% at 210 8C
8 min were obtained. In contrast, higher cellulose recoveries (99% at 190 8C
4 min and 88% at 210 8C
8 min) were obtained at larger particle sizes (8
12 mm).大部分的technoeconomic分析生物質(zhì)預(yù)處理已經(jīng)強(qiáng)調(diào)了三個(gè)主要參數(shù)的重要性在優(yōu)化過(guò)程和確保最大基質(zhì)利用率:(一)復(fù)蘇的纖維素在水中不溶性纖維。產(chǎn)量是表示為葡萄糖水不溶性纖維的除以潛在葡萄糖的原料。相比之下,高纖維素的復(fù)蘇(99%在190 8分鐘,88%在210年c4 8 c8 min)獲得了在大粒徑(8 12毫米)。在這些條件下,50%以上hemicellulosic 衍生糖得到復(fù)蘇。草本芯片可能熱更迅速比木屑和大小的芯片,在本試驗(yàn)范圍,不是重要的在溫度和住宅次研究工作。降低水解收率在190 8 c和4和8分鐘預(yù)處理?xiàng)l件,但沒(méi)有顯著差異粒徑。一般來(lái)說(shuō),聚糖在液體中分?jǐn)?shù)和纖維素在水中不溶性分?jǐn)?shù)需要溫和的嚴(yán)重程度,治療恢復(fù)正常高收益,但是,這些都是獲得以犧牲減少酶水解屈服。4顯示了纖維素葡萄糖制程良率(%)對(duì)不同預(yù)處理?xiàng)l件。因此,利用更大的芯片在蒸汽爆炸的草本農(nóng)業(yè)廢物將會(huì)是可行的優(yōu)化過(guò)程的有效性,提高經(jīng)濟(jì)通過(guò)減少銑削功率。更高的酶水解收益率(約99%)在210年獲得了8 c溫度。