Gas temperature rise and flame length induced by two buoyancy-controlled propane burners aligned parallel to the cross wind

This study was an investigation of the characteristics of a horizontal laminar diffusion flame established from a tubular burner in a buoyant vertical flow vitiated with combustion products created by a flat flame. The effects of varying flat flame equivalence ratio on these characteristics were studied. Applications of this study include exhaust gas recirculation (EGR), staged combustion in furnaces, and afterburners in jet engines. The fuel used for both the horizontal (cross-flow flame) and the flat flame in this study was propane. For a range of flat flame burner equivalence ratio (0.6 to 0.9), measurements of cross-flow flame length, and global emissions of NO were made. The mass flow rate of propane delivered to the cross-flow flame was held constant during these measurements. The flames were photographed with a digital camera. Profiles of combustion species concentrations and temperature were taken at 25% and 50% of the cross-flow flame length for flat flame burner equivalence ratios of 0.6 and 0.8, and for a non-combustion case (air flow only) in the flat flame. It was found that increasing the flat flame burner equivalence ratio caused an increase in the length of the cross-flow flame. The maximum temperature of the cross-flow flame decreased with increasing flat flame burner equivalence ratio. The introduction of the cross-flow flame increased the NO production in a flat flame with an equivalence ratio of 0.6, but did not significantly affect the NO production in a flat flame of an equivalence ratios of 0.7 or 0.8, and reduced it (by as much as 25%) in a flat flame of equivalence ratio of 0.9. This reduction of NO production and flame temperature and increase in flame length with increasing flat flame equivalence ratio was attributed to the reduction of oxygen available to the cross-flow flame. These results were supported with the in-flame combustion species concentration profiles.

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Advanced Boiler Cleaning Solutions for Increased Boiler Runtime

19th Annual North American Waste-to-Energy Conference ◽

10.1115/nawtec19-5425 ◽

2011 ◽

Author(s):

Brandon Billings ◽

Greg Rodia ◽

Ryan Scavone ◽

Marc Tirkschleit

Keyword(s):

Temperature Rise ◽

Flue Gas ◽

Operating Experience ◽

Waste To Energy ◽

Gas Temperature ◽

Energy Facility ◽

Custom Design ◽

Boiler Operation ◽

Clean System ◽

Pressure Water

Clyde Bergemann Power Group (CBPG) and Covanta Niagara, a Waste-to-Energy facility (WTE) plagued by boiler cleanliness issues, have collectively worked to implement a Shower Clean System (SCS) trial in Boiler 3’s second pass. The SCS’s cleaning concept is designed to traverse down through the roof of the boiler into a narrow open pass using a custom design water spray nozzle to clean the water walls. A SCS trial assembly was operated at the facility from July 27, 2010 to September 1, 2010. A total of 16 cleaning cycles were performed. During this trial period, on average, the second pass outlet flue gas temperature saw a 62 degrees Fahrenheit (degF) reduction after a cleaning event was performed. Based on years of SCS operating experience, CBPG determined a cleaning event should not be initiated if the temperature rise in the second pass is less than 30 degF. This insures that the second pass would not be over cleaned causing material stress to the water walls. In order to estimate the proper cleaning frequency for Niagara’s permanent SCS, an average second pass fouling rate was calculated. Using the fouling rate and the minimum allowable flue gas temperature rise, a cleaning frequency was estimated. Based on the trial results, the recommended operating frequency of the permanent SCS at Covanta Niagara will employ the Umbrella nozzle in the second pass twice per day or once per shift (12 hours). This recommendation is based on observations of the six week operating trial of the SCS and is subject to change based on myriad variables such as waste characteristics and first pass outlet flue gas temperatures. Typical boiler operation at Niagara utilizes industrial cleanings once per week to extend its boiler runtime. During the six week trial the SCS helped reduce the total number of industrial cleanings necessitated to keep the boiler online. Once a permanent SCS is implemented and used daily, there could be significant benefits to boiler runtime without having a total dependence on industrial cleanings. Becoming more reliant on the SCS to maintain lower boiler flue gas temperatures will result in less costs associated with online boiler cleaning and potentially less damage to the third pass convective surface from less high pressure water washing.

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Maximum gas temperature rise beneath the ceiling in a portals-sealed tunnel fire

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2018.05.021 ◽

2018 ◽

Vol 80 ◽

pp. 10-15 ◽

Cited By ~ 26

Author(s):

Yongzheng Yao ◽

Kun He ◽

Min Peng ◽

Long Shi ◽

Xudong Cheng ◽

...

Keyword(s):

Temperature Rise ◽

Gas Temperature ◽

Tunnel Fire

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Analysis of Fire and Explosion Properties of LNG

Safety & Fire Technology ◽

10.12845/sft.58.2.2021.4 ◽

2021 ◽

Vol 58 (2) ◽

pp. 58-73

Author(s):

Marzena Półka ◽

Robert Piec ◽

Dariusz Olcen

Keyword(s):

Thermal Exposure ◽

Flame Length ◽

Heating Time ◽

Hazardous Substances ◽

Gas Temperature ◽

Negative Effects ◽

Fire And Explosion ◽

Lng Fuel ◽

Technical Solutions ◽

Liquefied Gas

Aim: The aim of this article is to analyse fire and explosion properties of LNG along with the identification of hazards that may arise during emergency incidents involving it. The article is based on an analysis of the available literature and a full-scale experimental study involving a 200-liter LNG tank leading to a jet fire. Introduction: Safe use and proper transport of flammable and harmful substances, together with the analysis of the effects of threats, enable the reduction of the number of accidents and provide possible conditions for the evacuation of people and property in a hazard zone. The compilation and systematization of knowledge on the safe use of the environmentally friendly LNG fuel will allow for an increase in the scope of its use. It is consistent with the state’s sustainable development policy consisting in identifying threats or adjusting technical solutions that minimize losses in transport or industry. Methodology: There are many legal acts in the world regarding safe storage and transport of LNG. One of the most important is Directive 2012/18/EC known as “Seveso III”. This document contains requirements for the prevention of major accidents involving hazardous substances – including LNG – and ways to reduce their negative effects on human health and the environment. Relevant requirements have also been specified in standards, tests, articles and other international acts, including in the European agreement on the international carriage of dangerous goods by road (the so-called ADR Agreement). The article compares flammable and explosive parameters of LNG. Possible scenarios occurring during the release and ignition of the LNG vapour cloud have been shown. The change of pressure of LNG vapour in the 200 l tank as a function of its heating time in the burning spill of a mixture of gasoline and diesel fuel is presented. In such a thermal exposure, a jet fire with a flame length of up to 5 meters was obtained. Conclusions: The proper use of flammable gases should be a priority in ensuring fire and explosion safety in facilities, during transport, etc. Hence, recognizing the threats and comparing them, or matching technical solutions that minimize the effects of LNG failures will allow active inclusion of knowledge in this field in the process of protection against fire and explosion. In case of LNG storage, attention should be paid to the types of materials in the immediate vicinity of this liquefied gas in order to have sufficient mechanical properties at the lowest liquefied gas temperature. Keywords: LNG, fire safety, process safety Article type: review article

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Correlation of rate of gas temperature rise with mass loss rate in a ceiling vented compartment

Chinese Science Bulletin ◽

10.1007/s11434-014-0479-z ◽

2014 ◽

Vol 59 (33) ◽

pp. 4559-4567 ◽

Cited By ~ 6

Author(s):

Ruiyu Chen ◽

Shouxiang Lu ◽

Bosi Zhang ◽

Changhai Li ◽

Siuming Lo

Keyword(s):

Mass Loss ◽

Temperature Rise ◽

Loss Rate ◽

Mass Loss Rate ◽

Gas Temperature

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Fire Resistance Test of Concrete Composite Box Steel Girder Floor System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.665.188 ◽

2014 ◽

Vol 665 ◽

pp. 188-191

Author(s):

Jun Li Lv ◽

Kao Zhong Zhao

Keyword(s):

Temperature Rise ◽

Vertical Displacement ◽

System Structure ◽

Bottom Plate ◽

Large Temperature ◽

Steel Girder ◽

Whole Process ◽

Plane Plate ◽

The Cross ◽

Floor System

The concrete composite box steel girder floor system is a new box-section ribbed hollow floor system. It is an integral structure integrated the girder and plates by the “composite box”, one of the precast composite members and the rear casting ribbed girder and has been widely used in the buildings with large span and heavy load. The article researches its whole process under the effects of the fire and the service load. In the whole process of test, the temperature field, vertical displacement, displacement within the plane, plate edge corner and other parameters of the different sections have been measured. The results show that: the concrete at the bottom plate of the composite box bottom plate quickly bursts off during the fire; later, the bottom plate of the composite box is out of operation; the floor structure becomes cross girder structure; as the temperature rises, after the floor system structure becomes the cross girder structure, the torque of the four-side ribbed girder of the floor system increases and the diagonal cracks occur on the four-side ribbed girder; as the temperature rises, there is large temperature gradient on the floor system ribbed girder along with the cross section height; the flexural deformation occurs to the floor system while the expanding deflection occurs in the plane; the maximum vertical displacement is achieved after the temperature rise stops; along with the drop of the temperature, the flexural deformation gradually recovers; after the tested temperature rise has been conducted for 292 minutes, the floor system still has good fire resistant capacity

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CFD simulation of reactive flow in parallel flow regenerative shaft kilns using porous media model

Thermal Science ◽

10.2298/tsci210628281m ◽

2021 ◽

pp. 281-281

Author(s):

Kamyar Mohammadpour ◽

Ali Alkhalaf ◽

Ali Chitsazan ◽

Eckehard Specht

Keyword(s):

Porous Media ◽

Cross Section ◽

Cfd Simulation ◽

Packed Bed ◽

Flame Length ◽

Parallel Flow ◽

Reactive Flow ◽

Porous Media Model ◽

Temperature Homogenization ◽

The Cross

Understanding the flow pattern of the gas jets in packed beds can have considerable significance in improving reactor design and process optimization. This study researches the fuel diffusion in the radial direction and the flame length in a packed bed of a Parallel Flow Regenerative (PFR) Shaft kiln. This kiln is characterized that the fuel is injected vertically in the packed bed using a lot of lances in the cross-section while the combustion air is distributed continuously. Such a large, packed bed has to be approximated as a porous media. This assumption is used to model the reactive flow in the kilns. Using a box with 700 spheres of 52 mm spheres in Body-Centered Cube (B.C.C.) arrangement the local concentrations of injected nitrogen in airflow were measured. The measured values match approximately with those calculated with the Porous Media Model (PMM). The studied parameters are the number of burners and burner arrangements. The radial mixing of fuel and air in a packed bed is relatively bad. Therefore, a lot of burners are needed for better temperature homogenization in the cross-section.

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Optimization of Heat Transfer Process in a Walking Beam Reheat Furnace Using Computational Fluid Dynamics

Volume 8A: Heat Transfer and Thermal Engineering ◽

10.1115/imece2018-88117 ◽

2018 ◽

Author(s):

Yuchao Chen ◽

Armin K. Silaen ◽

Nicholas Walla ◽

Kurt Johnson ◽

Chenn Q. Zhou

Keyword(s):

Heat Transfer ◽

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Air Temperature ◽

Flow Rate ◽

Flame Length ◽

Slab Surface ◽

Gas Temperature ◽

Reheating Furnace ◽

Flame Angle

In the steelmaking process, reheating furnaces are used to reheat steel slabs to a target rolling temperature. The bottom intermediate zone inside the reheating furnace plays a decisive role in controlling the slab temperature distribution before slabs enter the soaking zone. Efforts to maintain a uniform slab surface temperature and thus enhance product quality require a good understanding of the furnace’s operation. However, traditional physical experiments are costly and have high risks as well. In this study, a three-dimensional steady-state computational fluid dynamics (CFD) model was developed to investigate the flow field in the bottom intermediate zone of a full-scale reheating furnace. The commercial software ANSYS Fluent® was used to solve the transport equations to predict the flame length, heat transfer, and gas temperature near the slab. Total input mass flow rate, preheated air temperature, and air/fuel ratio were selected to investigate the comprehensive influence of the furnace’s performance, which can be evaluated from the flame length, flame angle, and average gas temperature near the slab. Importantly, an orthogonal experimental design was conducted to optimize the evaluation factors by considering the multi influencing factors simultaneously. The simulation results indicate that a higher mass flow rate produces a lower upwards flame angle, which can prevent the hot spot detected on the slab surface. A higher preheated air temperature leads to a higher average gas temperature in this furnace; meanwhile, the flame becomes shorter by enhancing the air-fuel ratio.

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