scholarly journals Experimental and Theoretical Study of Heat Losses in Drying Cylinders

2021 ◽  
pp. 169-179
Author(s):  
Valeriy Sivakov ◽  
Keyword(s):  
Thermal Insulation ◽  
Ambient Air ◽  
Heat Losses ◽  
Paper Machine ◽  
Front Side ◽  
Steam Consumption ◽  
Refined Method ◽  
End Caps ◽  
Contact Drying ◽  
Drying Section

The research purpose is to develop methods for determination of heat losses in drying cylinders. Experimental study of temperature of drying cylinders performed in the drying section of a paper machine during its steady-state operation. Medium, maximum and permissible statistical characteristics of drying cylinder temperatures were defined. The drying cylinders with increased condensation concentration were determined by the minimally permissible temperature levels and the repair of the condensation drainage system to reduce heat losses (steam consumption) was justified. The cause of uneven dryness of the paper web across the width has been determined. The condensate ring on the inner wall at the edges of the drying cylinders gets thickened due to moisture coming from the end caps from the action of centrifugal forces. The condensation is removed from the drying cylinders with a siphon on the drive side. Therefore, on the front side of the drying cylinders condensate film has a greater thickness, and the paper web dries worse. The single-sided condensate disposal and the physical effect of centrifugal condensate runoff from the end caps to the side inner surface of the drying cylinders cause a lower dryness from the front side of the paper web. The use of thermal insulation of end caps will contribute to uniform dryness across the width of the paper web. The results of experimental studies were processed by methods of mathematical statistics in order to describe the thermal losses during contact drying of the paper web on drying cylinders with and without thermal insulation of the end caps to the ambient air. The calculation of heat losses is carried out according to the refined method of researching thermal processes in contact drying of paper web. It is found, that the use of thermal insulation of the end caps of the drying cylinders provides a reduction in steam consumption for contact drying of the paper web without affecting the technological process. The research results can be used to reduce heat losses in the drying section of paper machines on cylinders that do not have thermal insulation of the end caps. For instance, for a paper machine consisting of 56 cylinders with a diameter of 1500 mm and a capacity of 7000 kg/h of absolutely dry paper, insulating their end caps saves up to 223 kg/h of steam for drying the paper web. Methods of detection of drying cylinders with increased content of condensation on permissible levels of temperature is developed and approved. A refined method for determining thermal losses during contact drying of the paper web on drying cylinders has been developed.

scholarly journals Waste heat potentials in the drying section of the paper machine in Umka Cardboard Mill

2011 ◽  
Vol 15 (3) ◽  
pp. 735-747 ◽  
Author(s):  
Goran Jankes ◽  
Nikola Tanasic ◽  
Mirjana Stamenic ◽  
Vuk Adzic
Keyword(s):  
Thermal Efficiency ◽  
Energy Use ◽  
Waste Heat ◽  
Paper Industry ◽  
Ventilation System ◽  
Specific Energy Consumption ◽  
Paper Machine ◽  
Steam Consumption ◽  
Drying Section ◽  
Heat Released

Paper production is one of the most energy intensive industrial processes. The use of waste heat is very important for energy efficiency improvement in paper industry. This paper deals with methods for calculation of potentials of waste heat generated in paper/board production process. For that purpose, the material and heat balance of the cardboard machine at Umka Cardboard Mill has been determined. Field measurements were conducted in order to define the unknown values of process parameters used for calculation in the balance equations and modelling. The focus was given to the cardboard drying section, which consumes most of the energy supplied to the machine. Additional aim of the work presented in the paper was to evaluate the specific energy consumption and the thermal efficiency of all individual energy units within the machine?s drying section. The results indicate two main sources of waste heat: waste heat released to the atmosphere with the discharge air from the present waste heat recovery system (14,380 kW); and waste heat released into the hall from the machine and extracted by the hall ventilation system (4,430 kW). Waste heat from both sources is characterized by fairly low temperatures 58-75?? and fairly high moisture content (30-40 g/kg). The waste heat can be partly utilized for preheating the fresh air in cardboard drying process, saving up to 13% of steam consumption. The specific heat consumption and specific steam consumption (consumption per tonne of produced cardboard) of the machine was 1,490 kWh/t and 1.4 t/t, respectively. The thermal efficiency of drying section and coating drying section was 55.6% and 33.6%, respectively. All these figures imply necessity for further waste heat utilization with the aim of improving the efficiency of energy use.

scholarly journals Machine Learning-Based Energy System Model for Tissue Paper Machines

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 655
Author(s):  
Huanhuan Zhang ◽  
Jigeng Li ◽  
Mengna Hong
Keyword(s):  
Neural Network ◽  
Energy Consumption ◽  
Gradient Boosting ◽  
Paper Machine ◽  
Steam Consumption ◽  
Tissue Paper ◽  
Paper Machines ◽  
Energy Consumption Model ◽  
Extreme Gradient Boosting ◽  
Consumption Model

With the global energy crisis and environmental pollution intensifying, tissue papermaking enterprises urgently need to save energy. The energy consumption model is essential for the energy saving of tissue paper machines. The energy consumption of tissue paper machine is very complicated, and the workload and difficulty of using the mechanism model to establish the energy consumption model of tissue paper machine are very large. Therefore, this article aims to build an empirical energy consumption model for tissue paper machines. The energy consumption of this model includes electricity consumption and steam consumption. Since the process parameters have a great influence on the energy consumption of the tissue paper machines, this study uses three methods: linear regression, artificial neural network and extreme gradient boosting tree to establish the relationship between process parameters and power consumption, and process parameters and steam consumption. Then, the best power consumption model and the best steam consumption model are selected from the models established by linear regression, artificial neural network and the extreme gradient boosting tree. Further, they are combined into the energy consumption model of the tissue paper machine. Finally, the models established by the three methods are evaluated. The experimental results show that using the empirical model for tissue paper machine energy consumption modeling is feasible. The result also indicates that the power consumption model and steam consumption model established by the extreme gradient boosting tree are better than the models established by linear regression and artificial neural network. The experimental results show that the power consumption model and steam consumption model established by the extreme gradient boosting tree are better than the models established by linear regression and artificial neural network. The mean absolute percentage error of the electricity consumption model and the steam consumption model built by the extreme gradient boosting tree is approximately 2.72 and 1.87, respectively. The root mean square errors of these two models are about 4.74 and 0.03, respectively. The result also indicates that using the empirical model for tissue paper machine energy consumption modeling is feasible, and the extreme gradient boosting tree is an efficient method for modeling energy consumption of tissue paper machines.

scholarly journals Reduction of Heat Losses in a Pre-Insulated Network Located in Central Poland by Lowering the Operating Temperature of the Water and the Use of Egg-shaped Thermal Insulation: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2104 ◽  
Author(s):  
Dorota Anna Krawczyk ◽  
Tomasz Janusz Teleszewski
Keyword(s):  
Heat Loss ◽  
Thermal Insulation ◽  
Heat Losses ◽  
Ecological Effect ◽  
Operation Temperature ◽  
Supply Pipe ◽  
Insulation Thickness ◽  
Network Operation ◽  
Cross Section Geometry

This paper presents possible variants of reducing the heat loss in an existing heating network made from single pre-insulated pipes located in central Europe. In order to achieve this aim, simulations were carried out for five different variants related to the modification of the network operation temperature, replacement of a single network with a double pre-insulated one, and changes in the cross-section geometry of the thermal insulation of the double heating network from circular to egg-shaped. The proposed egg-shaped thermal insulation was obtained by modifying the shape of the Cassini oval, in that the supply pipe has a greater insulation thickness compared to the return pipe. The larger insulation field in the supply pipe contributed to reducing the heat flux density around the supply line and, as a result, to significantly reducing heat loss. The egg-shaped thermal insulation described in the publication in a mathematical formula can be used in practice. This work compares the heat losses for the presented variants and determines the ecological effect. Heat losses were determined using the boundary element method (BEM), using a proprietary computer program written as part of the VIPSKILLS 2016-1-PL01-KA203-026152 project Erasmus+.

scholarly journals Optimization for energy consumption in drying section of fluting paper machine

2017 ◽  
Vol 21 (3) ◽  
pp. 1419-1429
Author(s):  
Shaaban Ghodbanan ◽  
Reza Alizadeh ◽  
Sirous Shafiei
Keyword(s):  
Process Parameters ◽  
Heat Recovery ◽  
Production Capacity ◽  
Inequality Constraints ◽  
Optimization Method ◽  
Energy Performance ◽  
Operating Conditions ◽  
Paper Machine ◽  
Recovery Performance ◽  
Drying Section

Non-linear programming optimization method was used to optimize total steam and air consumption in the dryer section of multi-cylinder fluting paper machine. Equality constraints of the optimization model were obtained from specified process blocks considering mass and energy balance relationships in drying and heat recovery sections. Inequality constraints correspond to process parameters such as production capacity, operating conditions, and other limitations. Using the simulation, the process parameters can be optimized to improve the energy efficiency and heat recovery performance. For a corrugating machine, optimized parameters show the total steam use can be reduced by about 11% due to improvement of the heat recovery performance and optimization of the operating conditions such as inlet web dryness, evaporation rate, and exhaust air humidity, accordingly total steam consumption can be decreased from about 1.71 to 1.53 tonnes steam per tonne paper production. The humidity of the exhaust air should be kept as high as possible to optimize the energy performance and avoid condensation in the pocket dryers and hood exhaust air. So the simulation shows the supply air should be increased by about 10% to achieve optimal humidity level which was determined about 0.152 kgH2O/(kg dry air).

IMPROVING THE RELIABILITY OF THE FUEL OIL HEATING SYSTEM AT THE TYUMEN TETS-2

2021 ◽  
Vol 7 (1) ◽  
pp. 79-91
Author(s):  
Boris V. GRIGORIEV ◽  
Ulyana Yu. SHASTUNOVA
Keyword(s):  
Thermal Insulation ◽  
Heat Balance ◽  
Thermal Power ◽  
Heating System ◽  
Ambient Air ◽  
Fuel Oil ◽  
Calculation Methods ◽  
Input And Output ◽  
Energy Facility ◽  
The Heat Balance

This article describes an engineering solution that allows a significant reduction in the material costs of heating reserve fuel (fuel oil) at the energy facility of the Tyumen Thermal Power Plant No. 2 (TETs 2), as well as make the heating system more reliable and less energy-intensive. Using the methods for calculating the input and output parameters of the supply pipeline and finding the surface area of the heat exchange of the coil, the authors describe the means for finding the thickness of the thermal insulation of the pipe and tank. The main equations for creating calculation methods are the heat balance equation. Using the criterion dependencies has helped in calculating the process of convective heat transfer. In addition, the authors provide the graphs for determining the steam flow rate depending on the ambient air temperature and wind speed and nomograms for determining the temperature inside the thermal insulation of the tank.

scholarly journals Optimization of Geometric Parameters of Thermal Insulation of Pre-Insulated Double Pipes

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1012 ◽  
Author(s):  
Dorota Krawczyk ◽  
Tomasz Teleszewski
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Cross Section ◽  
Thermal Insulation ◽  
Major Axis ◽  
Heat Losses ◽  
Sectional Area ◽  
Cross Sectional ◽  
Elliptical Shape ◽  
Half Axis

This paper presents the analysis of the heat conduction of pre-insulated double ducts and the optimization of the shape of thermal insulation by applying an elliptical shape. The shape of the cross-section of the thermal insulation is significantly affected by the thermal efficiency of double pre-insulated networks. The thickness of the insulation from the external side of the supply and return pipes affects the heat losses of the double pre-insulated pipes, while the distance between the supply and return pipes influences the heat flux exchanged between these ducts. An assumed elliptical shape with a ratio of the major axis to the minor half axis of an ellipse equaling 1.93 was compared to thermal circular insulation with the same cross-sectional area. All calculations were made using the boundary element method (BEM) using a proprietary computer program written in Fortran as part of the VIPSKILLS project.

Analysis of the Influence of Transient State of the Overhead Pipeline Placed in an Open-Air Space on the Accuracy of its Insulation Assessment Based on the Results of Outer Shell Thermovision Diagnostics

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Tadeusz Kruczek
Keyword(s):  
Thermal Insulation ◽  
Thermal Protection ◽  
Thermal State ◽  
Infrared Camera ◽  
Transient State ◽  
Weather Conditions ◽  
Heat Losses ◽  
Energy Accumulation ◽  
Measurement Results

Abstract The proper thermal diagnostics of pipeline insulation is an important problem. The heat losses from the pipelines depend distinctly on the quality of this insulation. Changes in weather conditions cause transient accumulation of energy in the pipeline insulation and may cause difficulties during evaluation of the quality of the pipeline thermal insulation. Generally, the goal of this investigation was to identify the scale of energy accumulation inside thermal insulation. This is important because during the calculation of heat losses from thermal pipelines on the basis of infrared camera temperature measurement results usually a steady thermal state inside the insulation is assumed. In order to determine the distributions of the temperature inside the insulation, the calculations of the temperature changes inside the pipeline insulation for real changeable meteorological conditions with the use of software ansys-fluent and others have been carried out. Both the heat transfer between the inner pipeline tube and outer pipeline shell and energy accumulation inside the pipeline elements were considered. For the pipeline insulation evaluation purpose, different coefficients for the analysis of energy accumulation scale were defined and used. The measurement results of the temperature of inner pipeline tube and outer pipeline shell gathered during the operation of the special experimental rig were used as input data for the aforementioned numerical simulations. In these calculations, they constituted the first (Dirichlet's) boundary condition. The conclusions resulting from this work are useful for specialists involved in the technical evaluation of the thermal protection features of pipelines.

HEAT MONITORING OF HEATING SYSTEM PROTECTION OF A NEW PASSENGER TERMINAL OF THE SAMARA INTERNATIONAL AIRPORT «KURUMOCH»

2015 ◽  
Vol 5 (2) ◽  
pp. 107-112
Author(s):  
Aleksandr Anatol'evich CHULKOV
Keyword(s):  
Heat Transport ◽  
Thermal Insulation ◽  
Thermal State ◽  
Experimental Studies ◽  
Heating System ◽  
Heat Losses ◽  
Experimental Results ◽  
Galvanized Steel ◽  
Transport Systems ◽  
System Protection

The results of experimental studies of thermal state of heat transport lines are viewed. Ready-to-use PU foarm unsulation in polyethylene sheath is taken as thermal insulation of heating system lines under the ground. Readyto- use PU foarm unsulation in sheet galvanized steel sheath is taken as thermal insulation of heating system lines aboveground. Experimental results permit to determine real heat losses of heat transport systems.

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