Engineering Bulletin No 1: Boiler and Furnace Testing Informative Summary

Overview:

This bulletin, published in 1918 by the US Fuel Administration, serves as a guide for engineers and firemen in efficiently operating boilers and furnaces. It emphasizes the crucial role of regular testing in determining the efficiency of steam-powered plants and highlights the significant coal savings that can be achieved through improved operation. The document details a comprehensive approach to boiler testing, including the necessary apparatus, procedures for measuring coal and feedwater, and the calculation of essential metrics like efficiency, horsepower, and cost of evaporation.

The bulletin particularly emphasizes the importance of addressing excess air in the furnace, dirty heating surfaces, and loss of unburnt coal through the grates, as these factors contribute to low boiler efficiency and fuel waste. The text further outlines practical steps that can be taken to improve boiler performance, such as sealing leaks in the boiler setting, removing soot and scale, and implementing efficient firing techniques. It concludes by urging plant operators to prioritize the firing line in the boiler room, highlighting its patriotic and crucial role in the war effort.

Key findings:

Regular boiler testing is essential for identifying and reducing fuel waste.
Excess air is a major cause of low boiler efficiency and can be reduced through proper draft control and sealing leaks in the boiler setting.
Dirty heating surfaces hinder heat transfer and reduce efficiency, necessitating regular cleaning and maintenance.
Efficient firing techniques, like firing often and little at a time, can significantly improve combustion and reduce fuel consumption.

Learning:

Boiler testing basics: This text explains the fundamental principles of boiler testing, covering the measurement of coal, feedwater, steam pressure, and temperature.
- Measuring coal: Learn to weigh coal accurately using a wheelbarrow and platform scales.
- Measuring feedwater: Understand the use of water meters and the three-barrel method for measuring feedwater volume.
- Calculating efficiency: Learn to calculate boiler efficiency based on input heat (calorific value of coal) and output heat (heat used to evaporate water).
- Calculating horsepower: Understand the concept of boiler horsepower and how to determine the horsepower developed during a test.
Boosting boiler efficiency: Learn the common causes of low boiler efficiency (excess air, dirty surfaces, and coal loss) and discover practical solutions for improvement.
- Excess air: Understand the concept of excess air, how it leads to fuel waste, and the importance of sealing leaks and optimizing draft control.
- Dirty surfaces: Learn why dirty heating surfaces reduce efficiency and the need for regular cleaning and maintenance.
- Efficient firing: Understand the importance of firing often and little at a time for better combustion and improved efficiency.

Historical context:

This bulletin was published in 1918 during World War I. The US Fuel Administration was established to address the critical shortage of fuel during the war and to promote fuel conservation efforts. This bulletin exemplifies the urgent need for efficient energy utilization in wartime and reflects the significant role that industrial energy efficiency played in supporting the war effort.

Facts:

25 to 50 million tons of coal can be saved annually through improved steam-power plant operation. This fact emphasizes the potential for significant coal savings through efficiency improvements, highlighting the importance of boiler testing and optimization.
Excess air is the most significant preventable waste of coal in a boiler plant. This fact underscores the critical role of draft control and leak prevention in reducing fuel waste.
A boiler horsepower is defined as the evaporation of 34.5 pounds of water per hour from and at 212° F. This fact provides a standard unit for measuring boiler capacity and is important for comparing the performance of different boilers.
The heat required to evaporate water depends on the feed water temperature and the steam pressure. This fact explains why the factor of evaporation is crucial in accurately calculating boiler efficiency and provides a basis for understanding the influence of operational parameters on fuel consumption.
The heating value of coal is determined through a calorimeter test. This fact highlights the importance of fuel analysis in understanding the potential energy content of coal and its role in calculating boiler efficiency.
Dirty heating surfaces reduce boiler efficiency by preventing heat transfer from hot gases to water. This fact emphasizes the need for regular cleaning to maintain efficient heat transfer and reduce fuel waste.
The Bureau of Mines published a bulletin providing the analyses and heating values of various coal types from different US regions. This fact highlights the resource available for understanding the properties of coal used in a specific boiler and determining its approximate heating value.
Stirring the fire is generally discouraged, as it can lead to clinker formation and fuel waste. This fact emphasizes the importance of careful firing practices and the need to avoid unnecessary disruption of the fire bed.
Using a damper to control draft is more efficient than using ash-pit doors. This fact highlights the importance of optimizing draft control to minimize the amount of excess air entering the furnace.
Steam leaks and blow-off valve leaks waste heat and fuel. This fact emphasizes the importance of ensuring the tightness of all steam and water lines to minimize heat loss and fuel consumption.
Covering steam pipes and the tops of boilers helps prevent heat radiation and loss. This fact highlights the importance of minimizing heat loss through insulation and proper pipe covering.
The efficiency of a hand-fired boiler should not be less than 65 percent. This fact sets a benchmark for efficient operation of hand-fired boilers and provides a target for improvement efforts.
Boiler efficiency can be increased to 70 percent with careful management under good conditions. This fact demonstrates the potential for significant efficiency gains through proper operation and maintenance.
The uptake damper can be adjusted to optimize draft control and reduce excess air. This fact highlights a key parameter for controlling the amount of air entering the furnace.
Holes in the fire bed contribute to excess air and lower efficiency. This fact underscores the importance of maintaining a consistent and evenly-distributed fire bed for efficient combustion.
Clinkers on the side or bridge walls reduce the effective area of the grate. This fact emphasizes the need to prevent clinker formation for optimal air flow and fuel efficiency.
A hot fuel bed in the ash pit can warp and burn out the grates. This fact highlights the importance of maintaining a clean ash pit to protect the grates and prevent damage.
The average steam pressure and feed water temperature are key parameters for calculating the factor of evaporation. This fact highlights the importance of measuring these parameters accurately for proper efficiency calculations.
The factor of evaporation adjusts the actual evaporation for differences in feed water temperature and steam pressure. This fact explains why the factor of evaporation is crucial in accurately calculating boiler efficiency and provides a basis for understanding the influence of operational parameters on fuel consumption.
The cost of evaporating 1,000 pounds of water from and at 212° F. can be calculated based on the coal price and equivalent evaporation. This fact provides a metric for evaluating the economic performance of the boiler and highlighting the cost savings that can be achieved through improved efficiency.

Statistics:

5,000 pounds of coal: This is the total weight of coal fired during the example boiler test in the bulletin, serving as a basis for understanding the scale of operation.
35,000 pounds of water: This is the total weight of water evaporated during the example boiler test, providing context for the volume of water processed by the boiler.
10 hours: This is the duration of the example boiler test, highlighting the importance of extending tests for more accurate results.
180° F: This is the average feed water temperature during the example boiler test, showcasing the typical temperature range for feed water.
100 pounds per square inch: This is the average steam pressure during the example boiler test, reflecting the typical operating pressure of boilers.
1.0727: This is the factor of evaporation for the example boiler test, emphasizing its importance in adjusting the actual evaporation to the standard condition of “from and at 212° F.”
7.5 pounds: This is the equivalent evaporation per pound of coal for the example boiler test, showcasing the amount of water evaporated from and at 212° F. per pound of coal fired.
54%: This is the boiler efficiency calculated for the example boiler test, highlighting the potential for improvement in achieving higher efficiencies.
109 horsepower: This is the boiler horsepower developed during the example boiler test, indicating the power output of the boiler.
150 horsepower: This is the rated horsepower of the boiler in the example, reflecting the boiler’s capacity as determined by its heating surface area.
73%: This is the percentage of rated capacity developed during the example boiler test, indicating the boiler’s operational efficiency in terms of utilizing its full potential.
7 pounds: This is the actual evaporation per pound of coal for the example boiler test, illustrating the actual amount of water evaporated per pound of coal fired.
$3.60 per ton: This is the cost of coal used in the example boiler test, providing context for the economic considerations in evaluating boiler performance.
$0.24: This is the cost of evaporating 1,000 pounds of water from and at 212° F. based on the coal price and equivalent evaporation in the example, providing a metric for assessing economic efficiency.
13,500 B.t.u: This is the assumed heating value of the coal in the example, emphasizing the importance of knowing the energy content of the fuel in calculating boiler efficiency.
970.4 B.t.u: This is the latent heat of steam at atmospheric pressure, representing the heat required to change water at 212° F. to steam at 212° F.
9 pounds: This is the equivalent evaporation target per pound of coal to achieve a 65% boiler efficiency with coal having a heating value of 13,500 B.t.u., demonstrating the potential for increased efficiency.
8.36 pounds: This is the actual evaporation target per pound of coal to achieve a 65% boiler efficiency with a factor of evaporation of 1.0727, highlighting the specific requirements for achieving target performance.
20%: This represents the potential increase in steam production from the same weight of coal by achieving a 65% efficiency instead of 54%, emphasizing the significant benefits of efficiency improvements.
10 or 12 square feet of heating surface per horsepower: This ratio is commonly used in calculating the rated horsepower of stationary boilers, providing a basis for understanding the relationship between heating surface area and boiler capacity.

Terms:

Calorific Value: The amount of heat energy released when a unit mass of fuel is completely burned.
Boiler Horsepower: A unit of measure for the evaporation capacity of a boiler, equivalent to 34.5 pounds of water evaporated per hour from and at 212° F.
Heating Surface: The surface area of metal in a boiler exposed to hot gases on one side and water on the other, where heat transfer takes place.
Factor of Evaporation: A value used to adjust the actual evaporation to the standard condition of “from and at 212° F.” based on feed water temperature and steam pressure.
Equivalent Evaporation: The amount of water that would be evaporated from and at 212° F. by the heat energy used to evaporate a given amount of water under specific conditions.
Excess Air: The amount of air entering a furnace that is not needed for complete combustion, leading to heat loss and reduced efficiency.
Clinker: A hard, fused mass of ash that forms on the grate or in the furnace, hindering air flow and reducing efficiency.
Uptake Damper: A device used to regulate the draft in the uptake of a boiler, controlling the amount of air entering the furnace.
Latent Heat of Steam: The amount of heat energy required to change a unit mass of water at its boiling point into steam at the same temperature.
Rated Horsepower: The capacity of a boiler as determined by its heating surface area, typically calculated by dividing the heating surface by 10 or 12 square feet per horsepower.

Examples:

The use of a wheelbarrow and platform scales to accurately weigh coal during a test. This example illustrates a practical method for measuring coal consumption during a boiler test.
The three-barrel method for measuring feedwater volume, where water is transferred from two barrels to a third barrel on scales. This example provides a detailed description of a commonly used method for measuring feedwater volume in the absence of a meter.
The calculation of boiler efficiency based on the calorific value of coal and the equivalent evaporation of water. This example showcases the mathematical process of calculating boiler efficiency, highlighting the relationship between fuel input and steam output.
The example of a boiler with a 54% efficiency, illustrating how a low efficiency indicates wasteful operation. This example provides a concrete illustration of how efficiency can be used to assess boiler performance and identify areas for improvement.
The use of a chart to determine the equivalent evaporation required to achieve a desired boiler efficiency with a specific type of coal. This example demonstrates a graphical method for determining target performance metrics and identifying the necessary adjustments for achieving desired efficiency.
The use of a torch to identify air leaks in the boiler setting. This example provides a practical method for detecting air leaks, which are a major cause of excess air and reduced efficiency.
The importance of keeping the shell and tubes clean from soot and scale to improve heat transfer. This example highlights the role of maintenance in optimizing boiler performance and reducing fuel waste.
The example of firing often and little at a time for more uniform conditions and better combustion. This example illustrates the importance of proper firing techniques in achieving efficient combustion and maximizing fuel utilization.
The use of a damper instead of ash-pit doors to control draft and minimize excess air. This example showcases a practical tip for optimizing draft control and reducing fuel waste.
The importance of sealing steam pipes and valves to prevent steam leaks and heat loss. This example emphasizes the importance of maintaining tight connections and preventing heat loss through leaks.

Conclusion:

This 1918 Engineering Bulletin provides valuable insights into the importance of regular boiler testing for maximizing efficiency and reducing fuel waste. It underscores the need to address excess air, maintain clean heating surfaces, and implement efficient firing techniques to optimize boiler performance. The bulletin emphasizes that even seemingly small adjustments in operating practices can yield significant fuel savings and contribute to both economic efficiency and national resource conservation. The document reflects the importance of energy efficiency in supporting the war effort and its enduring relevance in promoting sustainable energy practices.

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