[1]朱 文,叶 平,张 辉*.宽区压榨毛毯-纸幅体系微观结构的研究[J].南京林业大学学报(自然科学版),2017,41(03):124-132.[doi:10.3969/j.issn.1000-2006.2017.03.019]
 ZHU Wen.,YE Ping,ZHANG Hui*.Research on microstructure of felt-sheet system (FSS)in press section with the extended pressing nip[J].Journal of Nanjing Forestry University(Natural Science Edition),2017,41(03):124-132.[doi:10.3969/j.issn.1000-2006.2017.03.019]
点击复制

宽区压榨毛毯-纸幅体系微观结构的研究/HTML
分享到:

《南京林业大学学报(自然科学版)》[ISSN:1000-2006/CN:32-1161/S]

卷:
41
期数:
2017年03期
页码:
124-132
栏目:
研究论文
出版日期:
2017-05-31

文章信息/Info

Title:
Research on microstructure of felt-sheet system (FSS)in press section with the extended pressing nip
文章编号:
1000-2006(2017)03-0124-09
作者:
朱 文13叶 平2张 辉13*
1.南京林业大学江苏省制浆造纸科学与技术重点实验室,江苏 南京 210037;
2.江苏金呢工程织物股份有限公司, 江苏 海门 226100;
3. 江苏省林业资源高效加工利用协同创新中心,江苏 南京 210037
Author(s):
ZHU Wen1.3 YE Ping2 ZHANG Hui13*
1.Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China;
2.Jiangsu Jinni Paper-making Felt Group, Haimen 226100, China;
3.Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing 210037, China
关键词:
宽区压榨 压榨模拟实验 毛毯-纸幅体系 微观结构 不均匀压缩假设
Keywords:
extended nip press model experiment of pressing felt-sheet system microstructure hypothesis on the uneven compression
分类号:
TS754; TS156
DOI:
10.3969/j.issn.1000-2006.2017.03.019
摘要:
【目的】了解毛毯-纸幅体系在压榨过程中的结构变化以及压缩速度、不均匀压力作用对于湿纸幅水分脱除动力学的影响。【方法】将毛毯和纸幅视作一个综合作用体系加以研究,首先研发了一套专门实验装置,通过压榨模拟实验研究压缩过程毛毯-纸幅体系微观结构上的变化,进而研究不同压缩速度、不同毛毯表面结构以及不同浆种对压缩过程所需压力的影响。【结果】①宽区压榨毛毯-纸幅体系微观结构为非均匀性结构; 靠近渗透毛毯表面最为致密,且最上层纸幅会嵌入毛毯纸幅空隙中,使得毛毯-纸幅体系整体渗透性降低,所需压榨压力增加。②采用铁丝面和中网面模型压缩过程中,当加压试验速度从51 mm/min变为99 mm/min时,后者压力峰值约为前者的4倍; 加压试验速度从99 mm/min变为124 mm/min时,后者压力峰值约为前者的2.3倍。但当压缩速度从124 mm/min变为99 mm/min(减小20%)时所需作用力减小了50%左右,并不符合达西定律。③在同一加压速度下,采用铁丝网面模拟压榨过程所需的压力是采用3种毛毯表面模型模拟压榨过程所需的压力的5倍左右。而采用3种毛毯表面模型模拟压榨过程所需的压力值几乎相同。④采用中网面毛毯表面模型时,当没有加入中间刚性层,试验速度从51 mm/min变为99 mm/min时,压缩过程所需的压力并没有明显的变化。当试验速度从99 mm/min变为124 mm/min(即增加25%)时,所需压力增加150%左右。在试验速度为51 mm/min时,压缩过程所需压力基本一致; 当试验速度为99 mm/min时,采用中间刚性层实验组所需的压力峰值比没有采用的组大; 当试验速度变成124 mm/min时,现象却相反。【结论】在压榨过程中纸幅模型在厚度方向上呈现不均匀性。纸幅模型在压缩过程中,压缩速度相同时压榨毛毯表面模型选用的不同,所需的载荷也不相同,当采用铁丝网面(即理想化平整的压榨表面)时,所需的压力最大; 而压缩速度越大,所需的压力值也就越大,且压力的大小与速度的变化关系并不符合达西定律。在纸幅模型层之间加入中间刚性层之后,相同的加压试验速度下,采用理想化细密平坦的压榨表面所需压力的峰值会减小。
Abstract:
【Objective】 The micro structure of felt-sheet systems(MSFSS)and its characteristics influence dewatering efficiency during pressing and is the basis upon which to develop new pressing technologies and new press felts for modern high-speed paper machines. 【Methods】The press felt and wet sheet were considered as one system, the felt-sheet system(FSS), in this study. First, a set of special experimental devices for the study was developed. Then, the change of the MSFSS in the press process was studied through a model experiment for pressing(MEP)using the device. Finally, the effects of different compressing velocities, surface structures of the press felt, and pulp types on the compressing force needed were determined. 【Results】The traditional hypothesis that the MSFSS is uniform, was incorrect. In fact, MSFSS was uneven and it appeared that, along the Z direction of the wet web and the pressure profile under the press roller’s force, the contacting area between web and felt can be divided into two parts—the ideal key pressing layer and the contact layer, in which there is a non-compressed layer with high permeability. 【Conclusion】The FSS in the direction of thickness appears uneven with stratification, and during the press process as the wet web is compressed unevenly. The non-compressed layer of FSS had advantages for the dewatering and compression process. The surface near the permeable felt was the most compact; the upper web layer would be implanted into the interspace of the FSS, which would reduce the permeability of FSS and lead to an increase in the necessary press pressure. The relationship between the pressure and compressing velocity did not conform to Darcy’s law. When the velocity exceeds a critical value, stratification will play an important part in press compression. It was also discovered that when the paper model was compressed using the wire press surface(an ideal flat permeable press surface), a peak force approximately six times higher than that for different felt surface models was required.

参考文献/References:

[1] 何北海.造纸原理与工程 [M].3版.北京:中国轻工业出版社,2010.
[2] 陈克复.制浆造纸机械与设备(下)[M]. 3版.北京:中国轻工业出版社,2011.
[3] 朱文,张辉. 现代纸机压榨毛毯及毛毯-纸幅体系的技术研究进展[J]. 中国造纸学报,2015, 30(4): 51-60. ZHU W, ZHANG H.Research progress on the press felt and felt-sheet system in the modern paper machine[J]. Transactions of China Pulp and Paper, 2015, 30(4): 51-60.
[4] 刘一山,吕向阳,韩邦春.造纸毛毯技术与应用[M].北京:中国轻工业出版社,2009:102-104.
[5] VOMHOFF H, NORMAN B. Model experiments on wet pressing[J]. Rdic Pulp and Paper Research Journal,1997,12(1):54-60.
[6] HAKALA T, HARLIN A. Simulation of a rapid nip pressure strike and its effect on press felt samples[J/OL]. Autex Research Journal, 2008(3):84-91. http://www.autexrj.arg/No.3-200810209.pdf.
[7] HAKALA T, WILENIUS T, HARLIN A. Laboratory ageing test device for press-felt clothes of paper machine[J/OL]. Autex Research Journal, 2007(7):70-79. http://www.autexrj.org/No.1.200710207.pdf..
[8] BURNS J R. Dynamic measurements of stratified consolidation in a press nip[J]. Tappi Journal, 1993, 76(8):87-96.
[9] JÖNSSON K A S, JÖNSSON B T L. Fluid flow in compressible porous media. I: steady-state conditions[J]. AIChE Journal, 1992, 38(9): 1340-1348. DOI:10.1002/aic.690380904.
[10] XU J. The effect of press felt non-uniformity on sheet smoothness and dewatering[J]. Paper Con, 2011:2143-2148.
[11] DRUMMOND D M D, RODRIGUES M T M, GROSSMANN I E, et al. Optimization of water removal in the press section of a paper machine[J]. Brazilian Journal of Chemical Engineering, 2010, 27(2): 275-288. DOI:10.1590/s0104-66322010000200006.
[12] 吕向阳, 伍安国, 刘一山. 造纸毛毯透通性指标的测试及其发展趋势[J]. 纸和造纸, 2010, 29(5): 12-16. LU X Y, WU A G, LIU Y S. Trend of development and test of permeability of papermaking felt[J]. Paper and Paper Making, 2010, 29(5): 12-16.
[13] 韩邦春,刘一山.压榨毛毯与造纸机的高效运行[J].纸和造纸,2012,31(2):12-14. HAN B C, LIU Y S.Effects of press felt on the efficient operation of paper machine[J].Paper and Paper Making, 2012,31(2):12-14.
[14] HAKALA T, HARLIN A. Crystallinity of polyamide 6 staple fibers in the felt structure under simulated paper machine conditions[J]. Journal of Applied Polymer Science, 2010, 120(4): 2222-2232. DOI:10.1002/app.33424.
[15] JÖRGEN G. The influence of stress variations in wet pressing[D]. Stockholm: Royal Institute of Technology, 2004.
[16] 韩邦春, 吕向阳. BOM毛毯的选用及影响其性能的关键因素(续)[J]. 中华纸业, 2007, 28(3): 73-76. DOI:10.3969/j.issn.1007-9211.2007.03.019. HAN B C, LU X Y. The selection of bom felt and the key factors influencing its performance[J]. China Pulp & Paper Industry, 2007, 28(3): 73-76. DOI:10.3969/j.issn.1007-9211.2007.03.019.

备注/Memo

备注/Memo:
收稿日期:2016-01-26 修回日期:2016-09-08
基金项目:江苏省制浆造纸科学与技术重点实验室开放基金资助项目(201409); 江苏高校优势学科建设工程资助项目(PAPD)
第一作者:朱文(839478079@qq.com)。*通信作者:张辉(zhnjfu@163.com),教授。
引文格式:朱文,叶平,张辉. 宽区压榨毛毯-纸幅体系微观结构的研究[J]. 南京林业大学学报(自然科学版),2017,41(3):124-132.
更新日期/Last Update: 2017-05-20