Optimisation of the alkaline peroxide pretreatment for the delignification of rice straw and its applications

Alkaline peroxide pretreatment for the delignification of rice straw was optimised by varying the concentrations of H₂O₂ and NaOH and changing the temperature and duration of the pretreatment. Changes in the lignin content, content of total carbohydrates and weight loss were measured during the pretreatments. Maximum delignification of 62% was obtained by pretreating rice straw at 50°C for 5h with 1.5% (w/v) NaOH and 1% (v/v) H₂O₂, The preferential loss of hemicellulose and lignin from the straw resulted in an increase in the cellulose content of the insoluble residue after pretreatment from 47% (untreated) to 67.79% (treated). The product of this treatment is characterised by having higher cellulose digestibility than untreated rice straw. It also has use as a carbohydrate source in ruminant feed since the in-vivo digestibility by the cow increased from 56.85 % to 76.54% (P < 0.001). The treated rice straw could also be used for commercial process such as the generation of Single Cell Protein. Growth of Sporotrichum pulverulentum on treated rice straw gave a protein product of 24.41 % as compared to 3.8% on untreated rice straw.     

Techno-economic and environmental aspects of the production of medium scale ligno-cellulosic ethanol under Egyptian conditions

As a result of actual pilot experimental data and guided by international and national reported estimates, this techno-economic study on a 20,000 ton/y ethanol production plant from rice straw has been conducted. The process essentially comprises preparation of the raw materials, alkaline pretreatment, simultaneous saccharification and fermentation (SSF) and dehydration. For the proposed capacity, costs have been estimated based on published information for the equipment as updated to 2013. Operating costs have been estimated according to experimental results of the research team and published information. Financial and sensitivity analyses have been conducted for optimistic and pessimistic scenarios for investment and operating costs and varying sales price of ethanol in the range $0.76/kg–$0.84/kg. Results indicate that positive present values have been obtained at the prevailing discount rate of 3%. The Internal Rate of Return (IRR) exceeds the discount rate considerably for the optimistic assumptions and is rather marginal for the pessimistic scenarios. In general, the process is considered technically and economically viable.     

秸秆气化集中供气技术在农村地区的应用

针对我国农村地区作物秸秆大量剩余，既浪费资源，又污染环境，文章通过秸秆气化集中供气技术应用实例，介绍秸秆气化原理，秸秆气化集中供气系统组成和以稻秆为原料的秸秆气化集中供气工程运行结果，并作简要分析，旨在为我国南方地区开发利用生物质能提供新的途径。     

Cellic CTec2水解常压甘油自催化预处理麦草的特性探讨

目前市场上商业纤维酶制剂产品很多,不同来源纤维素酶的基质适应性各不相同,所以产糖效果也存在显著差异。为了探究Cellic CTec2（CTec2）这种商业纤维素酶水解木质纤维素的特性,本文通过对酶解率测定探究了CTec2水解甘油预处理麦草的特性。研究发现,CTec2在2%浓度基质上酶解率远远高于其它三种商业纤维素酶-Celluclast1.5L、GC220和Spezyme-CP,而且它们两两之间没有协同水解甘油预处理麦草的作用。CTec2在高基质浓度条件下能较快水解液化木质纤维素基质,在15%基质浓度上按酶蛋白载量为8mg/g基质时,72h酶解率达到39.06%,而同条件下的其它三种酶几乎不能使基质液化。与其它纤维素酶一样,加入适量添加剂可以提高Ctec2水解甘油预处理麦草能力,添加量为0.05g/g基质的PEG10000、吐温20和BSA Ctec2的酶解率分别提高了55.3%、42.5%和38.3%。因此,Ctec2作为一种新型商业纤维素酶制剂,在纤维基质高浓水解方面将会有着潜在的应用前景。      

提高纸浆H2O2漂白效率的新途径

考察了麦草浆H2O2漂白过程中采用柠檬酸钠，沸石、蛋白石以及柠檬酸钠与沸石或蛋白石共用作为保护剂替代传统稳定剂和螯合剂的可能性。研究发现柠檬酸钠及柠檬酸钠与蛋白石共用在降低H2O2消耗和提高漂白效率方面具有明显效果，与无添加剂的H2O2漂白相比，纸浆白度提高4％－6％ISO，H2O2消耗降低20％－30％，其改善漂白效果的能力与传统添加剂相当，柠檬酸钠与蛋白石共用的添加工艺成本较低，有对环境友好，是提高纸浆H2O2漂白效率的一条新的有效途径。     

Sub- and supercritical liquefaction of rice straw in the presence of ethanol–water and 2-propanol–water mixture

The critical liquefaction of rice straw to bio-oil with sub- and supercritical mixtures (ethanol–water and 2-propanol–water mixture) was studied in a 1000 ml autoclave at 533–623 K, 6–18 MPa, respectively. The results showed that the maximum yield of bio-oil was 39.7% for the 2-propanol:water volume ratio of 5:5 at 573 K, while the higher heating value (HHV) of bio-oil increased with the reaction temperature and solvent volume ratio. The formation of low-boiling-point materials was reduced by a mixture. Using a mixture could inhibit the formation of residue and then promote the conversion of rice straw with the ratio of 1:9–5:5. The bio-oil was analyzed by GC/MS and Elemental Analyzer, while the morphological changes of residue were observed by a scanning electron microscope (SEM).     

一种轻质承重夹层墙板的承载能力试验分析

本文提出了一种以水泥刨花板为面层、以稻草板为芯层的承重夹层墙板的设计方案。介绍了墙板的复合技术，根据足尺寸墙板加载试验，分析研究了墙板的破坏形式和承载能力。     

Determination of lignin in the presence of ester-bound substituted cinnamic acids by a modified acetyl bromide procedure

The lignin content of plant materials can be determined spectro-scopically but the presence of ester-bound substituted cinnamic acids in the cell walls of some plant families, particularly the Gramineae, gives elevated values. Pre-treatment with either pyrrolidine : pyridine or 0-5 m sodium methoxide selectively removes the ester-bound acids leaving intact the true lignin. The treatments have been applied to cellulose powder, immature perennial ryegrass stems, oat straw and forage rape stems. The pyrrolidine : pyridine treatment removes a slightly higher proportion of these non-lignin components but the sodium methoxide treatment appears to cause less damage than the heterocyclic bases to other cell wall constituents and is preferred if the residues are to be used for other purposes.     

Comparison of atmospheric aqueous glycerol and steam explosion pretreatments of wheat straw for enhanced enzymatic hydrolysis

BACKGROUND: The oversupply of cheap glycerol by the oleochemicals industry together with problems occurring in low‐boiling‐point organosolv pretreatments, has generated an interest in the use of glycerol in the organosolv pretreatment of lignocellulosic biomass. Atmospheric aqueous glycerol autocatalytic organosolv pretreatment (AAGAOP) is a promising strategy that can effectively enhance enzymatic hydrolysis of lignocellulosic biomass. As a cost‐effective technique, steam explosion pretreatment (SEP) is being adopted in industrial applications. Accordingly, work has been carried out to investigate how AAGAOP enhanced enzymatic hydrolysis of lignocellulosic biomass compares with the SEP method. RESULTS: Under controlled laboratory conditions, based on ≥ 90% cellulose recovery, AAGAOP removed ≥ 60% hemicellulose and ≥ 60% lignin from wheat straw while SEP led to ～80% hemicellulose and 10% lignin removal. Enzymatic hydrolysis yields of AAGAOP and SEP reached ～90% and ～70%, respectively. Physical‐chemical structural characterization by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR), helped explain the above results. The two methods gave priority to dissociating the guaiacyl lignin and had a relatively small effect on syringyl units. However, AAGAOP exhibited a superior performance. CONCLUSION: The two methods enhanced the enzymatic hydrolysis of lignocellulosic biomass by removing and/or altering physical‐chemical structural impediments. The AAGAOP technique, with some special advantages, was more effective than SEP in enhancing the recovery and enzymatic digestibility of cellulose. Copyright © 2008 Society of Chemical Industry