Study On The Feature Of Black Liquor In Ethanol Pulping Of Reed And Application Of Ethanol Lignin In Paper Making

Ethanol-water pulping, which is one kind of organosolv pulping, takes on the advantagesof small investment, high yield, and utilizable effectively of by-products. And it cancompletely solve the pollution problem of conventional chemical pulping. In this paper, theorderliness and feature of ethanol-water pulping were investigated. And the recoveryutilization of black liquor was studied systematically.The delignification orderliness of auto-catalytic ethanol pulping and H₂O₂-catalyticethanol pulping of reed were studied and compared. Chemical analysis of pulp，indices ofwhich include yield, pulp selectivity, pH, and lignin content in the pulp, showed that Whenhydrogen peroxide was added to cooking liquor, delignification of reed, especially in themiddle lamellar（ML）, was speeded up while screened yield was slightly lowered, And time tomaximum cooking temperature of fiber liberation point didn’t change; Addition of hydrogenperoxide didn’t modify the pHase and the order of delignification reaction, but the rate orderwas enhanced. Then it is indicated through the research of Micro distribution of lignin in thecell wall with the aid of SEM+EDAX that in ethanol-water pulping process, the sequence oflignin removal follows the order: ML+P＞S₁＞S₃＞S₂; When the cooking time is over30min,the rate of delignification reaction depressed obviously except ML+P. Meanwhile, IRspectroscopic analysis of lignin in black liquor verified a part of conclusions above.Acid out method was adopted to abstract lignin in black liquor. Then black liquor wasdetached by air distillation method. Both qualitative and quantitative analyses of the cutfraction were proceeded by using gas chromatograpH. This study indicated that inauto-catalytic ethanol pulping process,4.5t ethanol（recovery of69.6%）,0.14t formate and0.17t lignin（recovery of63.2%） can be recovered and4.67t ethanol（recovery of70.5%）,0.18tformate and0.21t lignin （recovery of68.7%） can be recovered in H₂O₂-catalytic ethanolpulping process.In this paper, graft copolymerization of acrylamide onto reed ethanol lignin usingammonium persulfate-sodium bisulfate as initiator was investigated. Perpendicularexperiment was adopted to study the effect of mass ratio of lignin and AM, the amount of initiator, mass ratio reaction of （NH₄）₂S₂O₈and NaHSO₃, temperature and copolymerizationtime. And the opertima experiment condition was investigated. Suitable conditions for graftcopolymerization are: AM:reed ethanol lignin（quality ratio）＝1:1, amount of initiator50mmol/l, mass ratio reaction of （NH₄）₂S₂O₈: NaHSO₃（mol ratio）:4:1, temperature80℃,reaction time4h. The yield and graft efficiency were respectively obtained95%and90%.The structure of copolymer was characterized by FT-IR. The fact verified that reed ethanollignin has better chemical activity. In the academic foundation provided by studies above, theeffects of the conditions of graft copolymerization of acrylamide onto reed ethanol lignin onthe properties of paper strength were investigated. The results indicated that the most sensitivefactors affecting the properties of paper strength were mass ratio of lignin and AM and theamount of initiator. In the opertima experiment condition, tensile index, tear index andbursting index were enhanced by18%,6%, and20%respectively.The eventual economy estimate showed that in this experiment, the economic value ofproducts is less than the cost of pulping in ethanol pulping process. More studies are neededto develop the recovery utilization of black liquor.