The Thermal Efficiency of a Hand-Fired Natural-Draught Lancashire Boiler

1950 ◽  
Vol 162 (1) ◽  
pp. 20-26
Author(s):  
T. F. Hurley ◽  
W. J. Sparkes
Keyword(s):  
Thermal Efficiency ◽  
Considerable Increase ◽  
Heat Losses ◽  
Flue Gases ◽  
Maximum Efficiency ◽  
Research Station ◽  
Simple Method ◽  
Excess Air ◽  
Secondary Air ◽  
High Level

Following the development of the Fuel Research Station “smoke eliminator” fire doors for hand-fired, natural-draught Lancashire boilers, a series of trials was carried out to obtain figures for their performance under a variety of conditions. Most of the trials were made with one or other of two sizes (”singles” and “smalls”) of a Northumberland coal, which was chosen because of its tendency to make heavy smoke; similar results were obtained with both sizes. The figures obtained during these trials, together with those of a few supplementary trials, are used to illustrate the effects of certain variables upon the performance of a boiler of that type. The information presented includes (1) the correlation of smoke intensity with the composition of the flue gases and with thermal efficiency, (2) the use of secondary air and suitable methods of firing to reduce the heat losses caused by incomplete combustion, (3) the effect of too little and of too much excess air upon efficiency, and (4) the effect of load upon efficiency. With the special fire doors, the admission of secondary air over the fire could easily be controlled and a simple method of firing could be employed. In consequence, the efficiency of combustion was maintained at a consistently high level without calling for exceptional skill or effort on the part of the fireman. Maximum efficiency was obtained when the quantity of secondary air was just sufficient to eliminate smoke: decreasing the percentage of excess air by a small amount below the optimum had as bad an effect upon efficiency as a considerable increase. Varying the load also affected efficiency, the maximum being reached well below rated load, but the variation in efficiency between 40 and 100 per cent of full load was comparatively small.

scholarly journals Influence of moisture content of combusted wood on the thermal efficiency of a boiler

2017 ◽  
Vol 38 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Ladislav Dzurenda ◽  
Adrián Banski
Keyword(s):  
Carbon Monoxide ◽  
Moisture Content ◽  
Flue Gas ◽  
Thermal Efficiency ◽  
Heat Losses ◽  
Flue Gases ◽  
Heat Power ◽  
Emission Standards ◽  
Negative Effect ◽  
Gas Loss

Abstract In the paper the influence of moisture content of wood on the heat losses and thermal efficiency of a boiler is analysed. The moisture content of wood has a negative effect, especially on flue gas loss. The mathematical dependence of the thermal efficiency of a boiler is presented for the following boundary conditions: the moisture content of wood 10-60%, range of temperatures of emitted flue gases from the boiler into the atmosphere 120-200 C, the emissions meeting the emission standards: carbon monoxide 250 mgm−3, fly ash 50 mgm−3 and the heat power range 30-100%.

scholarly journals Modeling of the Thermal Efficiency of a Whole Cement Clinker Calcination System and Its Application on a 5000 MT/D Production Line

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5257
Author(s):  
Yanfei Yao ◽  
Songxiong Ding ◽  
Yanxin Chen
Keyword(s):  
Calcium Carbonate ◽  
Thermal Efficiency ◽  
Production Line ◽  
Cement Clinker ◽  
Specific Process ◽  
Excess Air ◽  
Positive Linear Correlation ◽  
Excess Air Coefficient ◽  
Secondary Air ◽  
The Relationship

This paper proposes that the scope of research should be extended to the whole clinker calcination system from its single device or specific process (i.e., its functional subunits) as conventionally conducted. Mass/heat flow and effective heat were first analyzed to obtain the thermal efficiencies of its subunits (φi); a thermal efficiency model of the whole system φQY was thus established by correlating the relationship between φi and φQY. The thermal efficiency model of the whole system showed that φi had a positive linear correlation with φQY; it was found that the thermal efficiency of the decomposition and clinker calcination unit (φDC) had the greatest weight on φQY, where a 1% increase in φDC led to a 1.73% increase in φQY—improving φDC was shown to be the most effective way to improve φQY. In this paper, the developed thermal efficiency model was applied to one 5000 MT/D production line. It was found that its φQY was only 61.70%—about 2.35% lower than a representative line; such decrease was caused by its low φDC and φP which, as disclosed by model, were derived from the low decomposition rate of calcium carbonate in preheated meal put into a calciner and the high excess air coefficient of secondary air. Controlled parameter optimization of this 5000 MT/D production line was then carried out. As a result, the φDC and φP of the production line were increased from 30.03% and 64.61% to 30.69% and 65.69%, respectively; the φQY increased from 61.70% to 62.55%; the clinker output of the production line increased from 5799 MT/D to 5968 MT/D; the heat consumption of clinker was reduced from 3286.98 kJ/kg·cl to 3252.41 kJ/kg·cl.

scholarly journals Effect of natural gas composition on reverberatory furnace thermal efficiency for nickel alloys

2020 ◽  
Vol 24 (5) ◽  
pp. 1159-1167
Author(s):  
Valeria Esthefanía Quiroz Cabascango ◽  
Keyword(s):  
Chemical Composition ◽  
Natural Gas ◽  
Thermal Efficiency ◽  
Nickel Alloys ◽  
Calorific Value ◽  
Reverberatory Furnace ◽  
Flue Gases ◽  
Physical Analysis ◽  
Aspen Hysys ◽  
Excess Air

The purpose of the article is to develop and substantiate the principles of an energy model of an industrial reverberatory furnace taking into account chemical composition and properties of natural gas as well as to calculate the furnace thermal efficiency in order to estimate its industrial performance. To conduct the research mathematical calculations are performed based on the data of chemical and physical analysis of flue gases and chimney temperature using standard graphs of excess air and enthalpy values of flue gas components. The measurement of the amount of waste pollutants is carried out using MRU Delta 65-3 gas analyzers, which identify the total amount of gases (O2, CO, NO, H2S) They determine the temperature, pressure (vacuum), calculate the content of CO2 and installation efficiency as well. Aspen Hysys program is used to verify the mathematical model. The data on the properties of natural gas are obtained including the data on chemical composition, molecular weight, calorific value, excess air during combustion. The data on flue gases are also obtained, which include the data on the burnt gas components, molecular weights, enthalpy, calorific value, flue gases ratio at the temperatures from 94°C to 316°C. The chemical reactions of combustion given with the number of moles required and formed for each reaction are used to calculate the thermal efficiency of a reverberatory furnace for nickel alloys. The calculated data are confirmed by Aspen Hysys software. Based on the studies conducted, it is found that the variable having the greatest influence on the thermal efficiency is the low calorific value, since it depends on the composition of the natural gas. The proposed methods for calculating the thermal efficiency using a computer program are effective if an operator wants to evaluate the furnace operation efficiency on site.

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

Heat Liberation and Transmission in Large Steam-Generating Plants

1933 ◽  
Vol 125 (1) ◽  
pp. 201-289
Author(s):  
E. W. Robey ◽  
W. F. Harlow
Keyword(s):  
Heat Liberation ◽  
Dew Point ◽  
Flue Gases ◽  
Plant Performance ◽  
Laboratory Research ◽  
Frictional Loss ◽  
Boiler Plant ◽  
Recent Developments ◽  
The Subject ◽  
Secondary Air

The demand for heavier duties and exacting guarantees of performance which has accompanied recent developments in steam-raising plants, has necessitated closer inquiry into the fundamental principles on which their performance depends. The authors present their views on certain aspects of the subject. These have been formed as a result of experience, combined with a consideration of the work of laboratory investigators. It would appear that important facts revealed by laboratory research do not always receive the attention due to them, and frequently erroneous ideas persist for years without question. The paper discusses the function of the chain grate mechanical stoker with particular reference to the subject of furnace design and secondary air application. It deals with the effect on the size and cost of equipment generally, which would result from a closer observance of the laws of heat transfer and frictional loss in flowing gases, and discusses particularly the phenomenon of delayed heat release in flue gases and the effect of this in boiler plant performance. The cause and prevention of air heater corrosion is dealt with, and the results of investigations into the dew point temperature of flue gases are given.

High Fidelity Modeling of the Acceleration of a Turboshaft Engine During a Restart

2018 ◽  
Author(s):  
Antoine Ferrand ◽  
Marc Bellenoue ◽  
Yves Bertin ◽  
Radu Cirligeanu ◽  
Patrick Marconi ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Combustion Efficiency ◽  
High Fidelity ◽  
Gas Generator ◽  
Idle Speed ◽  
Flight Mode ◽  
System States ◽  
Secondary Air ◽  
Turboshaft Engine ◽  
High Level

In order to decrease the fuel consumption, a new flight mode is being considered for twin-engine helicopters, in which one engine is put into sleeping mode (a mode in which the gas generator is kept at a stabilized, sub-idle speed by means of an electric motor, with no combustion), while the remaining engine operates at nominal load. The restart of the engine in sleeping mode is therefore deemed critical for safety reasons. This efficient new flight mode has raised the interest in the modeling of the restart of a turboshaft engine. In this context, the initial conditions of the simulations are better known relative to a ground start, in particular the air flow through the gas generator is constant, the fuel and oil system states are known and temperatures of the casings are equal to ambient. During the restart phase of the engine, the gas generator speed is kept at constant speed until the light-up is detected by a rise in inter-turbine temperature, then the starter torque increases, accelerating the engine towards idle speed. In this paper, the modeling of the acceleration of the gas generator from light-up to idle and above idle speeds is presented. Details on the light-up process are not addressed here. The study is based on the high-fidelity aero-thermodynamic restart model that is currently being developed for a 2000 horse power, free turbine turboshaft. In this case, the term high-fidelity refers not only to the modeling of the flow path components but it also includes all the subsystems, secondary air flows and controls with a high level of detail. The physical phenomena governing the acceleration of the turboshaft engine following a restart — mainly the transient evolution of the combustion efficiency and the power loss by heat soakage — are discussed in this paper and modeling solutions are presented. The results of the simulations are compared to engine test data, highlighting that the studied phenomena have an impact on the acceleration of the turboshaft engine and that the model is able to correctly predict acceleration trends.

scholarly journals Effects of the MHS locus on growth, carcass and meat quality traits in F<sub>2</sub> crosses between Mangalitza and Piétrain breeds

2000 ◽  
Vol 43 (3) ◽  
pp. 263-276 ◽  
Author(s):  
G. Thaller ◽  
L. Dempfle ◽  
A. Schlecht ◽  
S. Wiedemann ◽  
H. Eichinger ◽  
...  
Keyword(s):  
Meat Quality ◽  
Growth Traits ◽  
Live Weight ◽  
Negative Influence ◽  
Carcass Composition ◽  
Research Station ◽  
Dna Test ◽  
Whole Genome Scan ◽  
Group Sex ◽  
High Level

Abstract. A total of 345 F2 animals from a crossbred design Mangalitza (homozygous NN) x Piétrain (homozygous nn) were fed ad libitum at the institute's Thalhausen Research Station and slaughtered at a live weight of approximately 100 kg. MHS genotypes (67 nn, 192 Nn and 86 NN) were determined directly in a DNA test targeting the ryanodine reeeptor locus. Models for analysis of variance included sire, dam, pen, slaughter group, sex and MHS effects. Growth Performance was generally lower and carcass composition minor compared to other breeds and crosses. No significant differences were found between MHS genotypes for growth traits but NN animals tended to be less eflicient with respect to food conversion. However, nearly all measurements of the carcass showed significant differences between nn and NN which were especially pronounced for sidefat thickness (−7 1mm) fat over the musculus longissimus dorsi (−8.8 mm) and loin eye area (+8.7 cm2) as well as fat area (−5.1 cm2) We found Nn animals performing similar to NN animals due to incomplete dominance of the N allele. As expected nn had a substantial negative influence on meat quality compared to NN and Nn (e.g. −0.61 and −0.15 for pH 45 min, respectively). Intramuscular fat content was at a high level and nn had significantly lower values with differences of −0.40% and −0.25% relative to NN and Nn, respectively. A whole genome scan is currently underway with emphasis on fat measurements which showed promising Variation in this study.

Mukhaizna Steam Injectors Thermal Efficiency & Insulated tubing Pilot Evaluation

2015 ◽  
Author(s):  
Rashid Al Shaibi
Keyword(s):  
Thermal Efficiency ◽  
Outer Wall ◽  
Heat Losses ◽  
Oil Field ◽  
Evaluation Methodology ◽  
Base Line ◽  
Field Observations ◽  
Reference Base ◽  
Steam Flood ◽  
Deep Reservoir

Abstract Occidental operates a steam flood project in Mukhaizna which is a giant deep heavy oil field in south Oman. Wellbore heat losses from steam injectors is one of the challenges that degrades the steam flood thermal efficiency for a deep reservoir. In addition, wellbore heat losses increase the thermal stress on the casing and lead to wellbore damage. In aim to reduce wellbore heat losses, insulated tubing was introduced and a Pilot was carried out to select the optimum insulated tubing product in the market. Ten Injectors were instrumented and completed with insulated tubing from four different vendors in addition to two bare strings used as a reference base line. Data were collected and evaluated in eight months period. Field thermal conductivity was obtained for the tested products using DTS temperature data from the outermost casing, the Thermocouples data from the tubing outer wall and temperature logs during injection in aid of a calibrated wellbore model. The conducted analysis and the field observations were sufficient to resolve the thermal performance between the tested products. This paper describes the Pilot configuration and the evaluation methodology. Analysis output and field observations are summarized and presented in addition to the raw data collected from the instruments and temperature logs.

Different Chilling-Induced Symptoms and the Underlying Oxidative Stress and Antioxidative Defense in the Exocarp and Mesocarp of Immature Sponge Gourd (Luffa cylindrica) Fruit

2021 ◽  
Author(s):  
Pichaya Chuenchom ◽  
Sompoch Noichinda ◽  
Kitti Bodhipadma ◽  
Chalermchai Wongs-Aree ◽  
David W. M. Leung
Keyword(s):  
Oxidative Stress ◽  
Defense Mechanisms ◽  
Considerable Increase ◽  
Chilling Injury ◽  
Oxygen Species ◽  
Antioxidative Defense ◽  
Sponge Gourd ◽  
Lower Temperature ◽  
High Level ◽  
The Relationship

Immature sponge gourd fruit is consumed as a vegetable with a limited shelf life. Although cold storage is a simple and powerful tool for maintaining postharvest fruit quality, storage at a low temperature may not be appropriate for vegetables as some chilling injury (CI) of the immature sponge gourd fruit may occur. Therefore, this research aimed to elucidate the relationship between CI, oxidative stress, and the antioxidative defense mechanisms in the exocarp and mesocarp of immature sponge gourd fruit. After storage at 5°C for 6 days, visual CI symptoms, including browning and surface pitting, were found in the peel (exocarp) but not in the mesocarp. There were, however, more dead cells (stained by Evans blue) in the mesocarp of the fruit stored at 5°C. There was a more considerable increase in the electrolyte leakage rate in both fruit tissues held at 5°C than 25°C. The CI was correlated with malondialdehyde (MDA) levels in the tissues. The MDA of fruit exocarp at 5°C was 1.6 fold higher than that at 25°C on day 6, while the lipoxygenase (LOX) activity in mesocarp was 50% higher in fruit stored at a lower temperature. The action of ascorbate peroxidase (APX) was high in the exocarp of the fruit stored at 5°C, but there appeared to be a continuous depletion of the co-substrate or ascorbic acid. In conclusion, the CI in the exocarp was mainly associated with a high level of reactive oxygen species (ROS). In contrast, the CI in the mesocarp appeared to be primarily associated with increased lipid peroxidation by the elevated LOX activity under cold stress compared to storage at 25°C.

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