An experimental study of the effect of enzyme-assisted refining on energy consumption and paper properties for mixed hardwood pulp

RASHMI SINGH　NISHI K.BHARDWAJ　BIJAN CHOUDHURY

SUMMARY： Effects of enzyme pretreatment on energy consumption during refining and also on the pulp/paper quality were evaluated. A commercial enzyme liquid formulation was used to study the refining process of bleached mixed hardwood pulp at different doses and reaction times. Enzymes can improve as well as degrade fibre properties, depending on the treatment conditions. At an enzyme dose of 0.06 IU/g o.d. (international unit per gram oven-dry) pulp and 2 h reaction time, 18% reduction in refining energy to reach CSF 300±10 was achieved. The enzyme pretreatment affected web consolidation and also improved the paper strength properties tensile index and burst index by 15% and 13%, respectively. This improvement is mainly due to enhancement of interfibre bondings as revealed by scanning electron microscope (SEM) image analysis.

生物酶預(yù)處理對(duì)混合闊葉木漿磨漿能耗和紙張性能的影響

RASHMI SINGH　NISHI K.BHARDWAJ　BIJAN CHOUDHURY

?

APPITA 2014年第3期中英文摘要

An experimental study of the effect of enzyme-assisted refining on energy consumption and paper properties for mixed hardwood pulp

RASHMI SINGHNISHI K.BHARDWAJBIJAN CHOUDHURY

SUMMARY： Effects of enzyme pretreatment on energy consumption during refining and also on the pulp/paper quality were evaluated. A commercial enzyme liquid formulation was used to study the refining process of bleached mixed hardwood pulp at different doses and reaction times. Enzymes can improve as well as degrade fibre properties, depending on the treatment conditions. At an enzyme dose of 0.06 IU/g o.d. (international unit per gram oven-dry) pulp and 2 h reaction time, 18% reduction in refining energy to reach CSF 300±10 was achieved. The enzyme pretreatment affected web consolidation and also improved the paper strength properties tensile index and burst index by 15% and 13%, respectively. This improvement is mainly due to enhancement of interfibre bondings as revealed by scanning electron microscope (SEM) image analysis.

生物酶預(yù)處理對(duì)混合闊葉木漿磨漿能耗和紙張性能的影響

RASHMI SINGHNISHI K.BHARDWAJBIJAN CHOUDHURY

摘要:本實(shí)驗(yàn)研究了生物酶預(yù)處理對(duì)磨漿能耗和紙漿/紙張性能的影響。實(shí)驗(yàn)采用一種商業(yè)液體生物酶,在不同用量和反應(yīng)時(shí)間下對(duì)漂白混合闊葉木漿進(jìn)行預(yù)處理。實(shí)驗(yàn)結(jié)果表明,在不同的處理?xiàng)l件下,生物酶可以提高或降低纖維性能。當(dāng)生物酶用量達(dá)到0.06 IU/g絕干漿、反應(yīng)時(shí)間為2 h時(shí),可以使打漿到游離度(CSF )(300±10)mL的磨漿能耗下降18%。酶預(yù)處理影響了纖維網(wǎng)絡(luò)的整合,同時(shí)紙張抗張指數(shù)和耐破指數(shù)分別提高了15%和13%。掃描電子顯微鏡(SEM)圖像分析表明,這種改善主要是由于纖維之間的結(jié)合力得到了增強(qiáng)所致。 目前,除非情況特殊,生物質(zhì)燃料的低價(jià)值使得只有大型生物質(zhì)精煉廠才有可能實(shí)現(xiàn)盈利。大型生物質(zhì)精煉廠的建設(shè)需要投入大量的資金,因此有很大的商業(yè)風(fēng)險(xiǎn)。然而,一些公司由于有戰(zhàn)略上的原因,愿意進(jìn)入生物質(zhì)燃料市場(chǎng)。雖然從生物質(zhì)精煉中提取的燃料價(jià)值比較低,但其中混合在這些燃料中的一些化學(xué)組分有很高的商業(yè)價(jià)值。本文表明,通過(guò)從快速熱解的產(chǎn)品中提取某些化學(xué)物質(zhì)并把剩余組分當(dāng)作燃料出售,即使很小的生物質(zhì)精煉廠也能實(shí)現(xiàn)較好的經(jīng)濟(jì)回報(bào)。 通過(guò)采用高溫二氧化氯(D)和酸性條件下添加鉬酸鹽催化劑的過(guò)氧化氫(Pmo)(DPmo)漂白段比先前更溫和的漂白參數(shù),并通過(guò)平衡化學(xué)品用量、溫度、pH值和反應(yīng)時(shí)間,可以達(dá)到與參照紙漿幾乎完全相同的光學(xué)和強(qiáng)度性能。通過(guò)這種方式,總二氧化氯用量有可能下降27%。實(shí)現(xiàn)該成果的關(guān)鍵因素是較高的最終pH值以及在DPmo段中使用的螯合劑。影響Pmo漂白工段是否能夠被大規(guī)模推廣的關(guān)鍵因素仍然是是否能夠?qū)崿F(xiàn)工廠規(guī)模的鉬酸鹽催化劑的回收和循環(huán)使用。 建立了一個(gè)實(shí)驗(yàn)?zāi)Ｊ?用電凝聚和沉淀將膠印油墨分散液和膠印新聞洗滌過(guò)濾水去污凈化。結(jié)果發(fā)現(xiàn),未經(jīng)處理時(shí),模型膠印油墨在pH值4～11時(shí)是穩(wěn)定的,然而,與之不同的是,未經(jīng)處理的洗滌過(guò)濾水因pH值的變化而引起凝聚。使用不銹鋼陰極,發(fā)現(xiàn)銅陽(yáng)極比鋁陽(yáng)極更能有效地?cái)_亂膠印油墨的穩(wěn)定性,而且施加電流與油墨的穩(wěn)定性被擾亂有正交關(guān)系。更進(jìn)一步發(fā)現(xiàn),膠印油墨在堿性環(huán)境下是穩(wěn)定的,因而阻礙電凝聚和沉淀方式去脫除油墨。油墨的脫穩(wěn)定性取決于它在金屬兩極的相互作用下,以及其在酸性下的質(zhì)變。在酸性環(huán)境下,碳黑油墨粒子顯示出更為疏水,從而讓水電解所產(chǎn)生的氣泡更加容易收集這些油墨。 為了提高由陽(yáng)離子化然后酸水解而產(chǎn)生的第一代淀粉類固化劑(SBFs) 的使用方便性,分別采用酸水解、酶化水解和次氯酸鹽氧化來(lái)降低原生淀粉的分子質(zhì)量然后醚化的方式,產(chǎn)生出3種新的SBFs ,而這3種SBFs的置換程度和分子質(zhì)量均控制為相近。研究了這3種實(shí)驗(yàn)性的SBFs對(duì)溶解物質(zhì)和膠體物質(zhì)的控制能力以及紙張強(qiáng)度的影響,并與傳統(tǒng)的聚胺類固化物相比。結(jié)果顯示,聚胺類固化物對(duì)中和溶解物質(zhì)較好,而 SBFs 在固化膠體物質(zhì)方面更為出色,而且更好地提升紙張強(qiáng)度。在這些 SBFs 中,其對(duì)溶解物質(zhì)和膠體物質(zhì)的控制能力,從最好到最差的排列為：酶化水解,酸水解,以氯酸鹽氧化降解。

Biorefineries as sources of fuels and chemicals

GEOFF COVEYBRUCE ALLENDERBRONWYN LAYCOCK MIKE O’SHEA

SUMMARY： At present, the value of biofuels is such that only large biorefineries are likely to be economic except in special circumstances. Large biorefineries require a large capital investment and thus represent a large commercial risk. However, there are strategic reasons that make it desirable for some companies to enter the biofuels market now. Although the revenue from fuels from biorefineries is relatively low, some of the chemicals that form components of these fuels are of high inherent value. This paper shows that by extracting some chemicals from the products of fast pyrolysis and selling the remainder as fuel, even quite small biorefineries can become economically attractive.

通過(guò)生物質(zhì)精煉提取燃料和化學(xué)品

GEOFF COVEYBRUCE ALLENDERBRONWYN LAYCOCK MIKE O’SHEA

Optimizing the (DPmo) stage for delignification of softwood kraft pulp

THOMAS DIETZTHOMAS CLARKADRIAN LYSAGHT

SUMMARY： By applying bleaching parameters in the (DPmo) stage, which are more moderate compared to those in a previous study, and by balancing chemical charges, temperature, pH and retention time, optical and mechanical pulp properties can be achieved that are almost identical with those of reference pulps. In this way, total chlorine dioxide savings of up to 27% are possible. Key factors for the positive outcome of this study were a higher final pH and the use of a chelating agent in the (DPmo) stage. Key success factor for the broad introduction of Pmo-containing bleaching sequences still remains the mill-scale feasibility of a recovery and recycle process for the molybdate catalyst.

使用DPmo漂白段優(yōu)化針葉木硫酸鹽法漿脫木素工藝

THOMAS DIETZTHOMAS CLARKADRIAN LYSAGHT

Clarification of flexographic wastewater by electrocoagulation and electroflotation

AKPOJOTOR SHEMIJEFFERY HSIEH DANIEL LEE

SUMMARY： A model, flexographic ink dispersion and a flexographic newsprint wash filtrate were decontaminated with electrocoagulation and sedimentation. It was found that without treatment, the model flexographic ink was stable in the pH range of 4 to 11, however, unlike the model flexographic ink dispersion, pH changes induced coagulation in the untreated wash filtrate. Using a stainless steel cathode, it was found that a copper anode was more effective at destabilising flexographic ink than an aluminium anode and that applied current has a positive correlation with ink destabilisation. Additionally, it was found that at an alkaline pH the flexographic ink is stabilised, which prevents removal of the ink by electrocoagulation and sedimentation. The destabilisation of ink dispersions was attributed to their interactions with metal ions and protonation at acidic pH. Under acidic environment, it was suggested that the carbon black ink particles are more hydrophobic, and bubbles generated by the electrolysis of water easily collect these inks.

使用電凝聚法和電浮選法凈化膠印廢紙脫墨廢水

AKPOJOTOR SHEMIJEFFERY HSIEH DANIEL LEE

New starch-based fixing agents made by starch degradation followed by cationic etherification

LIJUN WANGTONGZHOU DILINGZHI LUOZHIJUN HU

SUMMARY： In improving the application convenience of the first generation of starch based fixing agents (SBFs) which are made by cationization followed by acid hydrolysis, three new SBFs were made respectively by degrading the molecular weight of raw starch with acid hydrolysis, enzymatic hydrolysis and hypochlorite oxidation, followed by etherification. The degree of substitution and molecular weight of the three SBFs were controlled to be similar. The performance of these experimental SBFs in controlling the dissolved and colloidal substances and paper strengthening was measured and compared to that of a traditional polyamine fixative. The results show that the polyamine fixative is better in neutralizing the dissolved substances, while the SBFs are better in fixing the colloidal substances and better in enhancing paper strengths. Among the SBFs, the effectiveness of controlling dissolved and colloidal substances and paper strengthening, from best to worst, is in the order of enzymatic, acid and finally hypochlorite degradation.

由淀粉降解然后陽(yáng)離子醚化而產(chǎn)生的新的淀粉類固化劑

LIJUN WANGTONGZHOU DILINGZHI LUOZHIJUN HU

APPITA Vol 67 No3-2014