scholarly journals Kraft recovery boiler operation with splash plate and/or beer can nozzles — a case study

TAPPI Journal ◽  
2021 ◽  
Vol 20 (10) ◽  
pp. 625-636
Author(s):  
VISWAMOORTHY RAJU ◽  
MARKUS ENGBLOM ◽  
EETU RANTALA ◽  
SONJA ENESTAM ◽  
JARMO MANSIKKASALO
Keyword(s):  
Gas Flow ◽  
Cfd Modeling ◽  
Back Wall ◽  
Behavior Simulation ◽  
Spray System ◽  
Model Predictions ◽  
Boiler Operation ◽  
Side Walls ◽  
Computational Fluid Dynamics Cfd

In this work, we study a boiler experiencing upper furnace plugging and availability issues. To improve the situation and increase boiler availability, the liquor spray system was tuned/modified by testing different combinations of splash plate and beer can nozzles. While beer cans are typically used in smaller furnaces, in this work, we considered a furnace with a large floor area for the study. The tested cases included: 1) all splash plate nozzles (original operation), 2) all beer can nozzles, and 3) splash plate nozzles on front and back wall and beer cans nozzles on side walls. We found that operating according to Case 3 resulted in improved overall boiler operation as compared to the original condition of using splash plates only. Additionally, we carried out computational fluid dynamics (CFD) modeling of the three liquor spray cases to better understand the furnace behavior in detail for the tested cases. Model predictions show details of furnace combustion characteristics such as temperature, turbulence, gas flow pattern, carryover, and char bed behavior. Simulation using only the beer can nozzles resulted in a clear reduction of carryover. However, at the same time, the predicted lower furnace temperatures close to the char bed were in some locations very low, indicating unstable bed burning. Compared to the first two cases, the model predictions using a mixed setup of splash plate and beer can nozzles showed lower carryover, but without the excessive lowering of gas temperatures close to the char bed.

CFD-modeling for more precise operation of the kraft recovery boiler

TAPPI Journal ◽  
2012 ◽  
Vol 11 (11) ◽  
pp. 19-27 ◽  
Author(s):  
MARKUS ENGBLOM ◽  
PASI MIIKKULAINEN ◽  
ANDERS BRINK ◽  
MIKKO HUPA
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
The Other ◽  
Cfd Modeling ◽  
Furnace Temperature ◽  
Model Predictions ◽  
Boiler Operation ◽  
Computational Fluid Dynamics Cfd ◽  
Recovery Boiler ◽  
Temperature Asymmetry

During kraft recovery boiler operation, situations can be encountered where the furnace temperature is asymmetric when comparing one side of the furnace to the other (i.e., left vs. right). In this paper, computational fluid dynamics (CFD) modeling is applied to study furnace load and liquor spraying as causes for asymmetric furnace temperatures in a 4450 tons dry solids (TDS)/day kraft recovery boiler. The model predictions are compared against validation measurements. Decrease in furnace load is identified as the main cause of the temperature asymmetry. The simulations also suggest that, at decreased load, relatively small differences in the tilts of individual liquor sprays can increase the temperature asymmetry.

scholarly journals Experimental and Numerical Studies of Hydrodynamics of Gas Flow through Orthogonal Networks

2018 ◽  
Author(s):  
Grzegorz Wałowski
Keyword(s):  
Kinetic Energy ◽  
Dissipation Rate ◽  
Gas Flow ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Cfd Modeling ◽  
Numerical Studies ◽  
Isotropic Porous Material ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

Simulation programs contain Computational Fluid Dynamics - CFD codes and are a useful tool used for gas flow through porous materials. Conducting numerical simulations allows for detailed analysis of hydrodynamic phenomena. The results of numerical modeling should always be verifiable based on experimental data. Only their compliance with the results of experimental tests is a determinant of the correctness of the applied method. As part of the work, experimental studies of hydrodynamics of gas flow through an isotropic porous material were carried out and numerical simulation for material of the same shape was used. In the CFD modeling Kolmogorov's hypothesis for the transport of kinetic energy of turbulence k and transport of dissipation rate of kinetic energy of turbulence ε was used.

Heat and mass transfer in wood composite panels during hot pressing: Part 3. Predicted variations and interactions of the pressing variables

Holzforschung ◽  
2007 ◽  
Vol 61 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Changming Yu ◽  
Chunping Dai ◽  
Brad Jianhe Wang
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Gas Flow ◽  
Structural Model ◽  
Governing Equations ◽  
Model Predictions ◽  
Temporal And Spatial ◽  
Resin Curing ◽  
Heat Conduction And Convection

Abstract As a continuation of previous publications on a physical-mathematical model of heat and mass transfer and a structural model of mat permeability, this paper presents typical prediction results for 15 pressing variables for strand mats. A case study and complete solutions to the governing equations are provided. The results show how the heat and mass transfer is controlled by heat conduction and convection involving gas flow and phase change. The model predictions provide a comprehensive illustration of the temporal and spatial variations of basic pressing variables, including mat temperature, gas pressure, moisture control and resin curing rate. The model offers a powerful tool for simulating the effects of mat structure, pressing schedule and initial mat conditions.

Simulation of an Industrial Tangentially Fired Boiler Firing Metallurgical Gases

2013 ◽  
Author(s):  
Guangwu Tang ◽  
Bin Wu ◽  
Kurt Johnson ◽  
Albert Kirk ◽  
Chenn Q. Zhou
Keyword(s):  
Electrical Power ◽  
Combustion Process ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Cfd Modeling ◽  
Steel Mill ◽  
Operation Conditions ◽  
Boiler Operation ◽  
Computational Fluid Dynamics Cfd ◽  
Industrial Boilers

In industrial environments, boiler units are widely used to supply heat and electrical power. At an integrated steel mill, industrial boilers combust a variable mixture of metallurgical gases combined with additional fuels to generate high-pressure superheated steam. Most tangentially fired boilers have experienced water wall tube failures in the combustion zone, which are thought to be caused by some deficiency in the combustion process. The challenge faced in this present process is that there are very limited means to observe the boiler operation. In this study, a three-dimensional Computational Fluid Dynamics (CFD) modeling and simulation of an industrial tangentially fired boiler firing metallurgical gases was conducted. Simulation results obtained from the assembled CFD model were validated by industrial experiments. A quick comparison of the flame shape from the simulation to the actual flame in the boiler showed a good agreement. The flow field and temperature distribution inside the tangentially fired boiler were analyzed under the operation conditions, and a wall water tube overheating problem was observed and directly related to the flow characteristics.

scholarly journals CFD Investigation of Rotational Sloshing Waves in a Top-Submerged-Lance Metal Bath

2021 ◽  
Author(s):  
D. Obiso ◽  
M. Reuter ◽  
A. Richter
Keyword(s):  
Gas Flow ◽  
Research Study ◽  
Cfd Modeling ◽  
Metal Bath ◽  
X Ray ◽  
Cylindrical Metal ◽  
Fundamental Research ◽  
Computational Fluid Dynamics Cfd ◽  
Metallic Bath ◽  
Submerged Lance

AbstractComputational fluid dynamics (CFD) is applied to investigate rotational sloshing waves in a top-submerged-lance (TSL) cylindrical metal bath. The study is an extension of a recent work of the authors, where the top injection of Ar into a metallic bath was examined in a quasi-2D flat setup, allowing the numerical model to be extensively validated against experimental data based on x-ray radiography. The new analysis of top gas injection in a cylindrical vessel reveals the appearance of rotational sloshing in the bath, which is maintained by a condition of synchronism between the gas bubbles and the free surface of the bath. A numerical quantification is achieved with specific post-processing of the simulation results, showing the effect of control parameters such as the lance immersion depth and the gas flow rate. This fundamental research study demonstrates the capability of CFD modeling to predict bath dynamics known from literature and practice, the understanding of which is essential for the design of TSL furnaces.

Recovery boiler sootblowers: History and technological advances

TAPPI Journal ◽  
2015 ◽  
Vol 14 (1) ◽  
pp. 51-60
Author(s):  
HONGHI TRAN ◽  
DANNY TANDRA
Keyword(s):  
Cfd Modeling ◽  
Computing Systems ◽  
The Past ◽  
Technological Advances ◽  
Recovery Boilers ◽  
Computational Fluid Dynamics Cfd ◽  
Recovery Boiler ◽  
Steam Parameters ◽  
Insight Into ◽  
Deposit Removal

Sootblowing technology used in recovery boilers originated from that used in coal-fired boilers. It started with manual cleaning with hand lancing and hand blowing, and evolved slowly into online sootblowing using retractable sootblowers. Since 1991, intensive research and development has focused on sootblowing jet fundamentals and deposit removal in recovery boilers. The results have provided much insight into sootblower jet hydrodynamics, how a sootblower jet interacts with tubes and deposits, and factors influencing its deposit removal efficiency, and have led to two important innovations: fully-expanded sootblower nozzles that are used in virtually all recovery boilers today, and the low pressure sootblowing technology that has been implemented in several new recovery boilers. The availability of powerful computing systems, superfast microprocessors and data acquisition systems, and versatile computational fluid dynamics (CFD) modeling capability in the past two decades has also contributed greatly to the advancement of sootblowing technology. High quality infrared inspection cameras have enabled mills to inspect the deposit buildup conditions in the boiler during operation, and helped identify problems with sootblower lance swinging and superheater platens and boiler bank tube vibrations. As the recovery boiler firing capacity and steam parameters have increased markedly in recent years, sootblowers have become larger and longer, and this can present a challenge in terms of both sootblower design and operation.

Passive Auto-Focus Algorithm for Correcting Image Distortions Caused by Gas Flow in High-Temperature Measurements of Surface Phenomena

2012 ◽  
Vol 17 (4) ◽  
pp. 379-384 ◽  
Author(s):  
Krzysztof Strzecha ◽  
Tomasz Koszmider ◽  
Damian Zarębski ◽  
Wojciech Łobodziński
Keyword(s):  
High Temperature ◽  
Gas Flow ◽  
Temperature Measurements ◽  
Surface Phenomena ◽  
Auto Focus ◽  
High Temperature Measurements

Abstract In this paper, a case-study of the auto-focus algorithm for correcting image distortions caused by gas flow in high-temperature measurements of surface phenomena is presented. This article shows results of proposed algorithm and methods for increasing its accuracy.

Effects of Over Fire Air on the Combustion and NOx Emission Characteristics of a 600 MW Opposed Swirling Fired Boiler

2012 ◽  
Vol 512-515 ◽  
pp. 2135-2142 ◽  
Author(s):  
Yu Peng Wu ◽  
Zhi Yong Wen ◽  
Yue Liang Shen ◽  
Qing Yan Fang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Empirical Method ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Cfd Model ◽  
Nitrogen Release ◽  
Computational Fluid Dynamics Cfd ◽  
Low Nox Emission

A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler

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