Optimum Heating of Thick Wall Pressure Components of Steam Boilers

2014 ◽  
Author(s):  
Piotr Dzierwa ◽  
Dawid Taler ◽  
Jan Taler ◽  
Marcin Trojan
Keyword(s):  
Heating Time ◽  
Thick Wall ◽  
Heating Process ◽  
Fluid Temperature ◽  
European Standard ◽  
Temperature Changes ◽  
Constant Rate ◽  
Steam Boilers ◽  
Optimum Heating ◽  
Temperature Heating

A method for determining time-optimum fluid temperature changes is presented. In contrast to present standards, two points at the edge of the opening are taken into consideration. The optimum fluid temperature changes are assumed in the form of a simple time function. It is possible to increase the fluid temperature stepwise and then the fluid temperature can be increased with a constant rate at the beginning of the heating process. Due to the stepwise increase in fluid temperature, heating time of a thick-walled component is of the same order as in the case of calculations according to EN 12952-3 European Standard, but the total circumferential stresses on the edge of the hole do not exceed the allowable value.

scholarly journals Optimum heating of cylindrical pressure components weakened by holes

2012 ◽  
Vol 33 (3) ◽  
pp. 106-116
Author(s):  
Piotr Dzierwa ◽  
Jan Taler
Keyword(s):  
Circumferential Stress ◽  
Longitudinal Section ◽  
Heating Time ◽  
Heating Process ◽  
Practical Reasons ◽  
Fluid Temperature ◽  
Optimum Temperature ◽  
Medium Temperature ◽  
Temperature Changes ◽  
Constant Rate

Abstract A method for determining time-optimum medium temperature changes is presented. The heating of the pressure elements will be conducted so that the circumferential stress caused by pressure and fluid temperature variations at the edge of the opening at the point of stress concentration, do not exceed the allowable value. In contrast to present standards, two points at the edge of the opening are taken into consideration. The first point, P1, is located at the cross section and the second, P2, at the longitudinal section of the vessel. It will be shown that the optimum temperature courses should be determined with respect to the total circumferential stress at the point P2, and not, as in the existing standards due to the stress at the point P1. Optimum fluid temperature changes are assumed in the form of simple time functions. For practical reasons the optimum temperature in the ramp form is preferred. It is possible to increase the fluid temperature stepwise at the beginning of the heating process and then increase the fluid temperature with the constant rate. Allowing stepwise fluid temperature increase at the beginning of heating ensures that the heating time of a thick-walled component is shorter than heating time resulting from the calculations according to EN 12952-3 European Standard.

Optimum Heating of Pressure Vessels With Holes

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Piotr Dzierwa ◽  
Jan Taler
Keyword(s):  
Stress Concentration ◽  
Circumferential Stress ◽  
Pressure Vessels ◽  
Heating Process ◽  
Fluid Temperature ◽  
Medium Temperature ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Constant Rate ◽  
Optimum Heating

A method for determining time-optimum medium temperature changes is presented. The heating of the pressure elements will be conducted so that the circumferential stress caused by pressure and fluid temperature variations at the edge of the opening at the point of stress concentration does not exceed the allowable value. In contrast to present standards, two points at the edge of the opening are taken into consideration. Optimum fluid temperature changes are assumed in the form of simple time functions. It is possible to increase the fluid temperature stepwise at the beginning of the heating process and then the fluid temperature can be increased with a constant rate.

scholarly journals New method for determining the optimum fluid temperature when heating pressure thick-walled components with openings

2019 ◽  
Vol 128 ◽  
pp. 01025
Author(s):  
Dawid Taler ◽  
Piotr Dzierwa ◽  
Jan Taler
Keyword(s):  
Circumferential Stress ◽  
Heating Process ◽  
Fluid Temperature ◽  
Allowable Stress ◽  
Optimum Temperature ◽  
Temperature Changes ◽  
Second Stage ◽  
Optimum Heating ◽  
Steady Temperature Field ◽  
Start Ups

A new approximate method of optimum heating cylindrical pressure elements weakened by openings was proposed. Optimum variations in fluid temperature when heating the pressure component were determined from the condition that the total circumferential stress at the edge of the opening, resulting from the thermal load and pressure is equal to the allowable stress. The allowable stress is determined from the Wöhler fatigue diagram for a given number of start-ups and shutdowns of a power unit from the cold state. Optimum temperature changes are difficult to estimate at the beginning of the heating, usingboth exact analytical and numerical methods. In case of analytical methods, this is due to the very slow convergence of a series for near-zero time in the exact solution. In this paper, the optimum temperature changes of the fluid at the beginning of heating were determined using the heat balance integralmethod (HBIM). This method makes it possible to determine with high accuracy the temperature of the fluid for times close to zero, i.e., at the beginning of the heating process. In the second stage of heating, the optimum fluid temperature was determined on the assumption of a quasi-steady temperature field in the pressure element.

Determining Optimum Temperature Changes During Heating of Pressure Vessels With Holes

2013 ◽  
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Dawid Taler
Keyword(s):  
Circumferential Stress ◽  
Longitudinal Section ◽  
Heating Time ◽  
Pressure Vessels ◽  
Heating Process ◽  
Practical Reasons ◽  
Fluid Temperature ◽  
Optimum Temperature ◽  
Medium Temperature ◽  
Temperature Changes

A method for determining time-optimum medium temperature changes is presented. The heating of the pressure elements will be conducted so that the circumferential stress caused by pressure and fluid temperature variations at the edge of the opening at the point of stress concentration, does not exceed the allowable value. In contrast to present standards, two points at the edge of the opening are taken into consideration. The first point P1 is located at the cross section and the second P2 at the longitudinal section of the vessel. It will be shown that the optimum temperature courses should be determined with respect to the total circumferential stress at the point P2, and not, as in the existing standards due to the stress at the point P1. Optimum fluid temperature changes are assumed in the form of simple time functions. For practical reasons the optimum temperature in the ramp form is preferred. It is possible to increase the fluid temperature stepwise at the beginning of the heating process and then the fluid temperature can be increased with a constant rate. By the stepwise increase in fluid temperature heating time of a thick-walled component is shorter than heating time resulting from the calculations according to EN 12952-3 European Standard.

Rancang Bangun Alat Olahan Minyak Kelapa

2016 ◽  
Vol 10 (1) ◽  
pp. 70-77
Author(s):  
Jantri Sirait ◽  
Sulharman Sulharman
Keyword(s):  
Electric Motor ◽  
Performance Test ◽  
Production Capacity ◽  
Coconut Oil ◽  
Heating Time ◽  
Design Tool ◽  
Coconut Milk ◽  
Heating Process ◽  
And Performance ◽  
Time Required

Has done design tool is a tool of refined coconut oil coconut grater, squeezer coconut milk and coconut oil heating, with the aim to streamline the time of making coconut oil and coconut oil increase production capacity. The research method consists of several stages, among others; image creation tool, procurement of materials research, cutting the material - the material framework of tools and performance test tools. The parameters observed during the performance test tools is time grated coconut, coconut milk bleeder capacity, the capacity of the boiler and the heating time of coconut oil. The design tool consists of three parts, namely a tool shaved coconut, coconut milk wringer and coconut milk heating devices. Materials used for the framework of such tools include iron UNP 6 meters long, 7.5 cm wide, 4 mm thick, while the motor uses an electric motor 0.25 HP 1430 rpm and to dampen the rotation electric motor rotation used gearbox with a ratio of round 1 : 60. the results of the design ie the time required for coconut menyerut average of 297 seconds, coconut milk wringer capacity of 5 kg of processes and using gauze pads to filter coconut pulp, as well as the heating process takes ± 2 hours with a capacity of 80 kg , The benefits of coconut oil refined tools are stripping time or split brief coconut average - average 7 seconds and coconut shell can be used as craft materials, processes extortion coconut milk quickly so the production capacity increased and the stirring process coconut oil mechanically.ABSTRAKTelah dilakukan rancang bangun alat olahan minyak kelapa yaitu alat pemarut kelapa, pemeras santan kelapa dan pemanas minyak kelapa, dengan tujuan untuk mengefisiensikan waktu pembuatan minyak kelapa serta meningkatkan kapasitas produksi minyak kelapa. Metode penelitian terdiri dari beberapa tahapan antara lain; pembuatan gambar alat, pengadaan bahan-bahan penelitian, pemotongan bahan - bahan rangka alat dan uji unjuk kerja alat. Parameter yang diamati pada saat uji unjuk kerja alat adalah waktu parut kelapa, kapasitas pemeras santan kelapa, kapasitas tungku pemanas serta waktu pemanasan minyak kelapa. Rancangan alat terdiri dari tiga bagian yaitu alat penyerut kelapa, alat pemeras santan kelapa dan alat pemanas santan kelapa. Bahan yang dipergunakan untuk rangka alat tersebut  yaitu besi UNP panjang 6 meter, lebar 7,5 cm, tebal 4 mm, sedangkan untuk motor penggerak menggunakan motor listrik 0,25 HP 1430 rpm dan untuk meredam putaran putaran motor listrik dipergunakan gearbox  dengan perbandingan putaran 1 : 60. Hasil dari rancangan tersebut yaitu waktu yang dibutuhkan untuk menyerut kelapa rata-rata 297 detik, kapasitas alat pemeras santan kelapa 5 kg sekali proses dan menggunakan kain kassa untuk menyaring ampas kelapa, serta Proses pemanasan membutuhkan waktu ± 2 jam dengan kapasitas 80 kg. Adapun keunggulan alat olahan minyak kelapa ini adalah waktu pengupasan atau belah kelapa singkat rata – rata 7 detik dan tempurung kelapa dapat digunakan sebagai bahan kerajinan, proses pemerasan santan kelapa cepat sehingga kapasitas produksi meningkat dan proses pengadukan minyak kelapa secara mekanis. Kata kunci : penyerut, pemeras, pemanas,minyak kelapa,olahan minyak kelapa.

Numerical Simulation and Process Optimization of Automotive Friction Materials in Warm Pressing Forming

2013 ◽  
Vol 788 ◽  
pp. 57-60
Author(s):  
Chun Cao ◽  
Chun Dong Zhu ◽  
Chen Fu
Keyword(s):  
Process Optimization ◽  
Heating Temperature ◽  
Maximum Energy ◽  
Heating Time ◽  
Product Performance ◽  
Forming Process ◽  
Friction Materials ◽  
Forming Technology ◽  
The Relationship ◽  
Temperature Heating

Warm pressing forming technology has been gradually applied to the forming of automotive friction materials. How to ensure product performance to achieve the target at the same time achieve the maximum energy saving is the research focus of this study. In this paper, by using finite element method, the field of automotive friction materials in warm pressing forming was analyzed, reveals the relationship between the temperature field and the heating temperature/heating time. Furthermore, the energy consumption was analyzed and compared it with hot pressing forming process. The results will have significant guiding to the process optimization in warm pressing forming.

scholarly journals The use of a solution of the inverse heat conduction problem to monitor thermal stresses

2019 ◽  
Vol 108 ◽  
pp. 01003
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Karol Kaczmarski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Power Plants ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Temperature Fields ◽  
Thick Wall ◽  
Fluid Temperature ◽  
Unsteady Temperature

Thick-wall components of the thermal power unit limit maximum heating and cooling rates during start-up or shut-down of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points respectively for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fastchanging fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using FEM (Finite Element Method) based on experimentally estimated fluid temperature and heat transfer coefficient

scholarly journals Numerical analysis of heat exchange process in the biomass carbonisation reactor

2019 ◽  
Vol 252 ◽  
pp. 05019 ◽  
Author(s):  
Robert Zarzycki ◽  
Justyna Jędras
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Numerical Analysis ◽  
Exchange Process ◽  
Geometrical Model ◽  
Heating Time ◽  
Heating Process ◽  
Hot Air ◽  
Cyclic Operation ◽  
Heat Exchange Process

The study presents the problem of heat exchange in the biomass carbonisation reactor with cyclic operation. Based on the actual parameter of the biomass carbonisation reactor, a geometrical model was developed, and the computation of the heating process was conducted for two cases: an empty reactor and a filled reactor. Its result demonstrated that for the analysed configuration of the reactor, the process of heating biomass in the containers is limited by the capability of heat transfer to the biomass in the container. The results suggest opportunities for the improved heat exchange in the reactor and, accordingly, shortening heating time through installation of the system that forces circulation of hot air inside the reactor.

scholarly journals Study on the Thermal Treatment of Nano-Ag/TiO2 Thin Film

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Peng Bing ◽  
Wang Jia ◽  
Chai Li-yuan ◽  
Wang Yun-yan ◽  
Mao Ai-li
Keyword(s):  
Thin Film ◽  
Methyl Orange ◽  
Thermal Treatment ◽  
Photocatalytic Degradation ◽  
Tio2 Thin Film ◽  
Heating Temperature ◽  
Antibacterial Properties ◽  
Heating Time ◽  
Degradation Rates ◽  
Temperature Heating

The photocatalytic degradation rates of methyl orange and antibacterial properties of nano-Ag/TiO2 thin film on ceramics were investigated in this study. XRD was used to detect the structure of film to clarify the impacts on the rates and properties. The effect of film layers, heating temperature, heating time, and embedding of Ag+ on the degradation rates and antibacterial properties were ascertained. The nano-Ag/TiO2 film of 3 layers with AgNO3 3% embedded and treated at 350°C for 2 h would exhibit good performance.

scholarly journals Pemanfaatan Gulma Siam (Chromolaena odarata L.) Sebagai Adsorben Logam Timbal

2020 ◽  
Vol 2 (1) ◽  
pp. 27-34
Author(s):  
Erni Mohamad ◽  
Intan J. Oputu ◽  
Julhim S. Tangio
Keyword(s):  
Activated Carbon ◽  
Activated Charcoal ◽  
Heating Time ◽  
Ion Adsorption ◽  
Chromolaena Odorata ◽  
Carbon Quality ◽  
Industry Standard ◽  
Optimum Ph ◽  
Optimum Heating ◽  
Time Required

This study aims to utilize (Chromolaena odorata L) as a metal adsorbent. The methods used to make activated charcoal are dehydration, carbonization, and activation. The activated carbon is then characterized to obtain activated charcoal that can be applied, then optimized. The results of activated carbon characterization obtained have reached the activated carbon quality requirements based on the Indonesian Industry Standard (SII No. 0258-88). Based on the adsorption test, the optimum pH of Pb2+ (Pb (NO3) 2 (in distilled water) Chromolaena odorata L charcoal activated by NaOH 0.2 M under varying pH (2,3,4,5,6) is at pH 5 with 69.00% absorption. The optimum contact time required for Pb ion adsorption is 4 hours at variation (1-5 hours) with 70.19% absorption. The optimum concentration at variation (concentration 20; 40; 60; 80; 100 ppm) on Pb ion adsorption is 100 ppm with 76.15% absorption. The optimum heating time is a variation of 1.5; 2; 2.5; and 3 hours of Pb ion adsorption is one hour 30 minutes with an absorption of 65.95%. Based on the optimization results, the activated carbon from the Chromolaena odorata L can be used as an adsorption material against the contamination of lead heavy metals (Pb).

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