Study On Methanol Formation And Its Mechanisms During Alkaline Pulping Process Of Silver Grass And Reed

The methanol formation and its mechanism in silver grass and reed alkaline pulping were mainly investigated in this paper. The results of methanol formation of silver grass with soda-AQ pulping process were as followsWhen the alkali charge added from10%to20%. the holding time extended from10to40min. the maximum temperature rised from145℃to170℃. the methanol formation increased from2.34to5.06kg/t(odp).2.08to3.88kg/t(odp).2.02to4.37kg/t(odp). respectively; Heat-up time had relatively less effect on the methanol formation, when the heat-up time raised from70to120min. the methanol formation increased from3.03to4.30kg/t.The results of methanol formation of silver grass with kraft pulping process were as follows:Alkali charge, holding time and maximum temperature had great influence on the methanol formation in kraft pulping process. When the alkali charge added from12%to22%. the holding time extended from10to40min. the maxium temperature rised from145℃to170℃. the melhanol formation increased from2.01to4.08kg/t(odp).1.75to3.14kg/t(odp).1.30to3.48kg/t(odp). respectively. Heat-up time had relativelv less influence on the methanol formation. when it raised from70to120min. the methanol formation increased from1.87to3.19kg/t(odp). Sulfidily made a little impact on the methanol formation, when the sulfidity enhanced from10%to25%. the methanol formation increased from2.36to2.78kg/t(odp).The methanol formation mechanism in the soda-AQ and kraft pulping process were preliminary studied, the results showed that with the increase of the alkali charge, holding time and maximum temperature, the lignin and pentosan disolving increased substantially, and the methanol formation rised remarkably, which were almost the same in both soda-AQ and kraft pulping process. Compared to other parameters, heat-up time had less effect on the lignin and pentosan dissolving. The methanol formation had no obviously increase with extending heat-up time. Lignin dissolving increased notably with enhancing sulfidity. while pentosan dissolving had only slightness increase, and the methanol formation had just a bit growth.The results of methanol formation of reed with soda-AQ pulping process were as follows:When the alkali charge added from16%to22%. the holding time extended from0to60min. the maximum temperature rised from145℃to165℃, the methanol formation increased from2.77to4.76kg/t(odp).2.02to5.06kg/t(odp).1.81to5.52kg/t(odp). respectively.The results of methanol formation of reed with kraft pulping process were as follows:When the alkali charge added from16%to22%, the holding time extended from0to60min, the maxium temperature rised from145℃to165℃, the methanol formation increased from2.72to4.12kg/t(odp),2.03to4.06kg/t(odp),2.23to4.67kg/t(odp), respectively. Sulfidity made a little impact on the methanol formation. When the sulfidity enhanced from10%to25%, the methanol formation increased from2.54to3.88kg/t(odp).