scholarly journals Theoretical Estimation of Evaporation Heat in Paper Drying Process Based on Drying Curve

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1117
Author(s):  
Xiaobin Chen ◽  
Qifu Zheng ◽  
Yunyuan Dong
Keyword(s):  
Traditional Method ◽  
Theoretical Method ◽  
Easy Access ◽  
Theoretical Estimation ◽  
Drying Process ◽  
Estimation Model ◽  
Paper Drying ◽  
Test Speed ◽  
Evaporation Heat ◽  
Drying Curve

At present, the theoretical estimation of paper web’s evaporation heat is based on sorption isothermals. The measuring conditions are harsh, and the test speed is slow. This paper attempts to explore a theoretical method which can quickly determine the evaporation heat of paper web. During the new method, based on the measurement of the paper drying curve, the theoretical estimation model of paper evaporation heat was obtained by deducing the mechanism of heat and mass transfer. Compared with the traditional method based on sorption isothermals, the new model based on the drying curve has some advantages in measurement speed and easy access to basic data. Finally, the paper verifies the reliability of the model from two application scenarios of the laboratory and production line.

Modeling of Energy-Saving Optimization Model by Sub-Sheet Dryness Coordination Based on Muti-Agent

2011 ◽  
Vol 347-353 ◽  
pp. 3171-3174
Author(s):  
Ding Hua Zhang ◽  
Huan Bin Liu ◽  
Ji Geng Li
Keyword(s):  
Energy Consumption ◽  
Energy Balance ◽  
Network Topology ◽  
Optimization Model ◽  
Optimal Algorithms ◽  
Drying Process ◽  
Paper Drying ◽  
Contract Net ◽  
Linear Complementary Problem ◽  
Multi Agent

According to Multi-Agent network topology of the globe energy node in papermaking dryer section, the optimal algorithms of each part of sheet for energy consumption node Agent is designed through the mentality of designing. And multi-Agent contract net protocol is improved based on the gambling solution of mixed linear complementary problem. The overall steam saving optimization can be achieved by coordinated and local optimization and globe energy balance of each energy node for the four group of paper drying process.

Investigation of Flashing Flow in a Siphon to Extract Condensate in Paper Dryer Application

2019 ◽  
Author(s):  
Hamed Abdul Majeed ◽  
Ting Wang
Keyword(s):  
Cfd Simulation ◽  
Paper Industry ◽  
Volume Ratio ◽  
Piping System ◽  
Drying Process ◽  
Local Pressure ◽  
Steam Consumption ◽  
Paper Drying ◽  
Computational Fluid Dynamics Cfd ◽  
State Case

Abstract The paper industry uses steam to dry paper web through cylinder dryers. As steam condenses inside the cylinder dryer, the condensate is removed by means of either a stationary or a rotary siphon. However, during the siphoning process for transporting the condensate, flashing of the condensate occurs, which could cause backflow or discontinuity in the siphoning process. To resolve this flashing issue, two approaches have been employed: (a) increasing the amount of steam supplied to the cylinder to “blow-through” the stalled condensate-steam mixture and (b) reducing the back pressure by inducing “suction” through a thermocompressor from downstream. This practice of employing push from the upstream and suction from the downstream requires excessively large amounts of high-grade steam, resulting in an estimated 10 to 15 %, 15 to 25%, and 40 to 90 % of blow-through steam for stationary siphons, rotary siphons, and Yankee dryers respectively. The objective of this study is to investigate and improve understanding of the flashing phenomena during condensate transport through the siphon and piping system in order to develop means to reduce this excessive steam consumption during the paper drying process. A computational fluid dynamics (CFD) simulation is performed that uses the Eulerian-Eulerian multiphase method. The steady-state case is first solved to obtain the flow field without flashing. Then the transient method is initiated by employing flashing and condensation models. The results show that reduction of local pressure triggers flashing, however, flashing in turn reduces local temperature, and subsequently induces condensation, resulting in an alternating flashing and condensation behavior. To maintain continuity of the siphon flow, the inlet pressure fluctuates corresponding to the variation of total vapor volume ratio inside the siphon. The results will be used to modify the current siphon system design and operating practices to reduce steam consumption.

Numerical and Experimental Fractal Pore Network Study on Drying of Porous Media: Numerical Simulation

2012 ◽  
Vol 557-559 ◽  
pp. 2167-2170
Author(s):  
Yue Jin Yuan ◽  
Yue Ding Yuan ◽  
Ying Ying Xu ◽  
Ji Xian Dong ◽  
Xiang Dong Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Porous Media ◽  
Pore Network ◽  
Pore Network Model ◽  
Drying Process ◽  
Drying Time ◽  
State Heat ◽  
Steady State Heat Transfer ◽  
Drying Curve

In order to validate the model established in reference [1], a drying experimental study was conducted, and numerical simulation was carried out under the same environmental condition. The experiment and simulation results indicated that the fractal pore network model could explain the drying process of real porous media effectively, the drying curve of fractal models was more consistent with the real drying curve than that of regular models, and its moisture fields well reflected the drying kinetics characteristic of real porous media. There was no correlation between the pore fractal dimension and the drying time, and the simulation result of unsteady-state heat transfer was more consistent with a real drying process than that of steady-state heat transfer for the convective thermal drying.

Spraying starch on the Fourdrinier— An option between wet end starch and the size press

TAPPI Journal ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 21-26
Author(s):  
COLE PRICE ◽  
MARTIN A. HUBBE
Keyword(s):  
Bonding Strength ◽  
Fiber Suspension ◽  
Paper Machine ◽  
Drying Process ◽  
Starch Solution ◽  
Paper Drying ◽  
Starch Grains ◽  
Wet Surface ◽  
Recycled Fibers

Technology to apply suspensions of starch grains to the wet surface of paper, during the dewatering process, is reviewed. Though the technology is not new, it continues to attract the attention of papermakers as a means to increase bonding strength. Starch grains that are sprayed onto the wet-web of paper can be retained at levels exceeding what can be effectively added to the fiber suspension at the wet end. Unlike adding a starch solution at a size press, no additional drying capacity is required on the paper machine. To be effective, the starch needs to be able to swell and develop bonding during the paper drying process. Paperboard applications with recycled fibers appear to be a good fit. There is potential to increase bonding by processes that favor fuller gelatinization of the starch grains by the time the paper becomes dry.

Fundamental understanding of removal of liquid thin film trapped between fibers in the paper drying process: A microscopic approach

TAPPI Journal ◽  
2020 ◽  
Vol 19 (5) ◽  
pp. 249-258
Author(s):  
ZAHRA NOORI ◽  
JAMAL S. YAGOOBI ◽  
BURT S. TILLEY
Keyword(s):  
Thin Film ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Bound Water ◽  
Free Water ◽  
Intermediate Stage ◽  
Convective Drying ◽  
Drying Process ◽  
Paper Drying ◽  
Vof Model

In the fabrication of paper, a slurry with cellulose fibers and other matter is drained, pressed, and dried. The latter step requires considerable energy consumption. In the structure of wet paper, there are two differ-ent types of water: free water and bound water. Free water can be removed most effectively. However, removing bound water consumes a large portion of energy during the process. The focus of this paper is on the intermediate stage of the drying process, from free water toward bound water where the remaining free water is present on the surfaces of the fibers in the form of a liquid film. For simplicity, the drying process considered in this study corresponds to pure convective drying through the paper sheet. The physics of removing a thin liquid film trapped between fibers in the paper drying process is explored. The film is assumed to be incompressible, viscous, and subject to evaporation, thermocapillarity, and surface tension. By using a volume of fluid (VOF) model, the effect of the previously mentioned parameters on drying behavior of the thin film is investigated.

Simulation of Drying Hevea brasiliensis Wood

2015 ◽  
Vol 1088 ◽  
pp. 802-806 ◽  
Author(s):  
Cláudio de Conti ◽  
Andrea Cressoni de Conti ◽  
Maristela Gava ◽  
Luiz Oliveira Veriano dalla Valentina ◽  
Glaucia Aparecida Prates
Keyword(s):  
Moisture Content ◽  
Statistical Method ◽  
Temperature Increase ◽  
Gravimetric Method ◽  
Average Moisture Content ◽  
Drying Process ◽  
Chi Square ◽  
Drying Time ◽  
Kiln Temperature ◽  
Drying Curve

The Simpson model proposes that the rate of wood drying is directly proportional to average moisture content. In this work was done the fitting and the reproduction of drying curve forHeveabrasiliensiswood through of Simpson model and the chi-square statistical method. The curves were obtained by drying 108 specimensHeveabrasiliensiswood with size 10 mm x 20 mm x 100 mm that were drying in a laboratory kiln. The drying control was performed through gradual temperature increase in order to minimize the errors arising due the drastic loss of moisture by wood. The gravimetric method was used to evaluate the drying process, the specimens have theirs mass measured every 6 hours until the timber reached the theoretical anhydrous state. The drying curve of rubber wood obtained here can be used to estimate the drying time of this species for different kiln temperature settings.

Energy system diagnosis of paper-drying process, Part 1: Energy performance assessment

2015 ◽  
Vol 34 (8) ◽  
pp. 930-943 ◽  
Author(s):  
Xiaobin Chen ◽  
Jigeng Li ◽  
Huanbin Liu ◽  
Yongjun Yin ◽  
Mengna Hong ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Energy System ◽  
Energy Performance ◽  
Drying Process ◽  
Paper Drying ◽  
System Diagnosis

scholarly journals Optimasi Suhu Pengeringan dan Ketebalan Irisan pada Proses Pengeringan Jahe Merah (Zingiber officinale var. rubrum) dengan Response Surface Methodology (RSM)

2021 ◽  
Vol 9 (1) ◽  
pp. 66
Author(s):  
Desak Agung Hepi ◽  
Ni Luh Yulianti ◽  
Yohanes Setiyo
Keyword(s):  
Response Surface Methodology ◽  
Water Content ◽  
Response Surface ◽  
Water Activity ◽  
Ash Content ◽  
Heat Energy ◽  
Slice Thickness ◽  
Drying Process ◽  
Drying Temperature ◽  
Evaporation Heat

Suhu pengeringan dan ketebalan irisan merupakan dua hal yang mempengaruhi proses pengeringan jahe merah. Penelitian dirancang dengan tujuan untuk mendapatkan kombinasi suhu pengeringan dan ketebalan irisan optimum melalui Response Surface Methodology (RSM), serta memperoleh model matematika untuk memprediksi kadar air, aktivitas air, kadar abu dan energi panas penguapan. Pengujian dilakukan untuk mengetahui pengaruh suhu dan ketebalan irisan terhadap respon kadar air, aktivitas air, kadar abu dan energi panas penguapan. Pengolahan data menggunakan aplikasi Design Expert ® 12. Hasil penelitian menunjukkan model linier untuk memprediksi respon kadar air dan kadar abu. Model kuadratik untuk memprediksi respon aktivitas air dan energi panas penguapan. Hasil verifikasi model menunjukkan kombinasi suhu pengeringan dan ketebalan irisan optimum terpilih adalah 67,30C dan 3 mm. Proses pengeringan dengan kombinasi suhu pengeringan dan ketebalan irisan optimum menghasilkan nilai aktual aktivitas air 0,393 aw, kadar air 9,877%, kadar abu 3,513% dan energi panas penguapan sebesar 68,354 kJ/Jam. Respon dari kombinasi suhu pengeringan dan ketebalan irisan optimum terpilih dapat memenuhi keinginan sesuai kriteria dengan nilai desirability 81,3%.   Drying temperature and thickness of slices are two things that affect the drying process of red ginger. The research was designed with the aim of obtaining a combination of drying temperature and optimum slice thickness through the Response Surface Methodology (RSM), as well as obtaining mathematical models to predict water content, water activity, ash content and evaporation heat energy. Testing was conducted to determine the effect of the temperature and thickness of the slices on the response of water content, water activity, ash content and evaporation heat energy. Data processing using design expert application ® 12. The results showed linear models to predict the response of water levels and ash levels. Quadratic models to predict the response of water activity and evaporation heat energy. Model verification results show the combination of drying temperature and optimum slice thickness selected is 67.30C and 3 mm. The drying process with a combination of drying temperature and optimum slice thickness resulted in an actual water activity value of 0.393 aw, water content of 9.877%, ash content of 3.513% and evaporation heat energy of 68,354 kJ/h. The response of the combination drying temperature and thickness of selected optimum slices can meet the wishes according to the criteria with a desirability value of 81.3%.

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