Study On Energy Consumption Nodes Of APMP Fiber By MC-refining

For chemical mechanical pulp refining, its mechanism on high energy consumption hasbeen still a riddle in the field of world pulp&paper research. In this dissertation, therelationships of fiber characteristics and energy consumption and paper properties weremainly concentrated during fiber cell structural fracture by eucalyptus and poplar APMP fiberMC-refining. The refining energy consumption nodes and its tiny nodes were concluded aswell. Finally, the measure of saving energy was presented.In this dissertation, the relationship of APMP fiber characterictics, refining energyconsumption and its nodes was analysed by PFI MC-refining. Results showed that the nodesof refining energy consumption were located in fiber length, fines and Kink index. A linearrelationship was found between Refining energy consumption and the impacting number byrefining (equivalent to PFI refining revolutions), the linear relation is: y=ex+b. In thisdissertation, the refining intensity e is the part of the energy consumption had been transferredto the fiber itself by refining action.During PFI MC refining, the linear relationship between fiber length and energyconsumption leads to the formula of fiber length real-time expression, l=l0-∫0ldl=l0-ke∫0tdt.Furthermore, an exponential relationship between fines and fiber length can be expressed as, f=k1e-ke∫dt, e, k and k1depend on raw material type and the fiber initial characteritics. In addition,for eucalyptus wood APMP, there is a polynomial relationship between its fiber length andKink index (fines and Kink index, similar relationship). Other parameters, such as fiber width,fiber coarseness, vessles and fiber curl, cannot built a regular relationship with refining energyconsumption and fiber length. In one word, refining action cannot control theabove-mentioned parameters regularly.In this dissertation, the relationship of handsheet properties, refining energy consumptionand its nodes was analysed as well. Tensile strength and fiber length, fines, refining energyconsumption, PFI revolutions (impacting times), Kink index has a polynomial relationship orits trend respectively; Further, a polynomial relationship or its trend lies between strain brakeand the fiber length, fines, energy consumption, PFI revolutions (impacting times), Kinkindex, respectively; A polynomial relationship or its trend lies between TEA index and tensile strength, fiber length, fines, energy consumption, PFI revolutions (impacting times), Kinkindex, respectively; A irregular relationship lies between tear index and tensile strength, strainbrake, TEA index, fiber length, fines, refining energy consumption, PFI revolutions(impacting times), the Kink index, respectively.If the cell walls of S2layer has not been fibrillated, its tensile strength and fiber length,fines, refining energy consumption, PFI revolutions (impacting times) has a polynomialrelationship respectively; Further, a polynomial relationship lies between strain brake andtensile strength, fiber length, fines, refining energy consumption, PFI revolutions (impactingtimes); A exponential relationship lies between TEA index and tensile strength; A polynomialrelationship lies between TEA index and fiber length, fines, energy consumption, PFIrevolutions (impacting times), respectively; A irregular relationship lies between tear indexand tensile strength, strain brake, TEA index, fiber length, fines, refining energy consumption,PFI revolutions (impacting times), the Kink index, respectively.In this dissertation, the effect on energy consumption and its nodes, cell wall fracture andcell surface morphologies change during CMC assisted MC refining paper was also analyzed.Results show that the key factor of affecting refining energy consumption nodes is themicrofibril Angle of S2layer, but the initial length of fiber and the thickness of cell wall alsocannot be ignored. S2layer microfibril Angle can affect fiber length, fines and Kink index.Smaller microfibril Angle of S2layer with lower Kink index needs higher refining energyconsumption. Especially, at the later refining stage, fiber strength reinforcement effect shouldbe avoided. Refining parameters can be optimized by referring to the starting point and thebest point of S2layer fibrillation. Analysis showed that CMC assisted MC refining is helpfulin saving energy consumption by reducing refining intensity, anyway, the rate of energysaving is about8%.Analysis also showed, with eucalyptus wood APMP fiber as an example, during MCrefining, fiber width changed a little, but fiber coarseness is related to cell wall delaminationand peeling off; fines is related to fiber length change and P&S1layer microfibrillation andpeeling off, as the peeling off of the two layers, fines is greatly increased about64.5%; Kinkindex has a huge falling about88%as S2layer peeling of and cell wall breakdown; Fiber curlchange is related with cell wall collapse and occurs mostly during P and S2layer peeling off and cell wall distroyed; Vessels surface area has a greatly increase about29%with P layerpeeling off and has a sharply falling about53%as well with S2layer peeling off, andincreased about30%again with cell wall broken. Fiber length has a drop about25%with P&S1layer and layer peeling off, continuously, has a drop about6%with S2layermicrofibrillation. From the best point to maximize point of S2layer microfibrillation, fiberlength, Kink index, vessels, fines and fiber curl are almost no changed. With S2layer peelingoff, fiber length decreased about9%, and with cell wall destroyed, fiber length decreasedabout4%again. By the cell wall surface morphological changes in MC refining, the subnodesof energy consumption from strong to weak are: fines, vessels, fiber length, fiber coarsenessand Kink index during ML and P layer peeling off; During S1layer microfibrillation andpeeling off, the subnodes of energy consumption from strong to weak are: Kink index, finesand fiber length; During the initial stage of S2layer microfibrillation, the subnodes of energyconsumption from strong to weak are: vessels, Kink index, fiber coarseness, fines and fibercurl, fiber length; During S2layer peeling off and S3layer microfibrillation, the subnodes ofenergy consumption from strong to weak are: vessels, Kink index, fines, fiber length and fibercurl; During cell wall fracture, the subnodes of energy consumption from strong to weak are:vessels, fines, Kink index, fiber length and fiber curl.Finally, this paper also proposed the saving measures of APMP fiber refining energy:according to the structural characteristics of fiber properties, and final requirement of APMPfiber, the refining plate should be chosen and the parameters of the refining process should beadjusted, then energy saving can be realized, during refining, using chemical additive can beadjustable fiber reinforcement of cell wall which can realize the advantages of energy savingand improvement of APMP fiber performance.