"Fuel Utilization and Environmental Protection" Mechanical energy, internal energy and their conversion PPT courseware 4

Description

"Fuel Utilization and Environmental Protection" Mechanical energy, internal energy and their conversion PPT courseware 4

teaching objectives

1. Know the calorific value of fuel and its calculation

2. Understand what thermal engine efficiency is and the main ways to improve thermal engine efficiency

3. Know the relationship between boilers and environmental protection

Fuel and its calorific value

The graph on the right shows the monthly consumption of a certain fuel for a family of four. Using different fuels, the consumption is different. Why?

What fuels are commonly used in daily life?

Common fuels include coal, petroleum (processed and refined into gasoline, kerosene, diesel and liquefied gas, etc.), natural gas, etc. In rural areas, straw from vegetation and other plants is also used as fuel.

calorific value of fuel

Different fuels of equal mass release different amounts of heat when completely burned.

In physics, the heat released when 1kg of a certain fuel is completely burned is called the calorific value of the fuel.

The energy released by complete combustion of fuel with mass m is:

Q=mq

Q: Heat released by complete combustion of fuel

q: Calorific value of fuel

m: mass of fuel

Heat engine efficiency

It can be seen from the figure that the energy actually absorbed by the water in the boiler and used to do useful work is only a part of the energy released when the fuel is burned.

The ratio of the energy converted into useful work by the heat engine to the energy released by complete combustion of the fuel is called the heat engine efficiency, that is: η = Q absorption / Q release × 100%

Dangers of acid rain

1. Direct harm to human health: Sulfuric acid mist and sulfate salt mist are much more toxic than sulfur dioxide and can invade the deep tissues of the lungs, causing pulmonary edema and other diseases that can lead to death.

2. Cause water acidification in rivers and lakes, seriously affecting the growth of aquatic animals and plants.

3. Destroy soil, vegetation and forests.

4. Corrodes metal, paint, leather, textiles and building materials.

5. Penetrate into the ground, making the content of aluminum, copper, zinc, and cadmium in the water many times higher than that in neutral groundwater.

How to protect our environment?

1. Improve combustion equipment and install smoke and dust removal devices;

2. Central heating;

3. Switch to gas fuel and popularize coal gas and natural gas;

4. Fully develop and utilize new energy sources with less pollution and no pollution.

Class exercises

1. The average monthly consumption of a family of four using different types of fuel separately is: about 200 kilograms of firewood, about 80 kilograms of bituminous coal, about 30 kilograms of liquefied petroleum gas, and about 60 kilograms of coal gas. Among these four fuels, the one with the highest calorific value is ()

A. Liquefied petroleum gas B. Coal gas

C. Bituminous coal D. Firewood

2. Rockets in the aerospace industry use liquid hydrogen as fuel. This is because liquid hydrogen has ( )

A. Smaller mass B. Smaller density

C. Larger specific heat capacity D. Larger calorific value

3. Diesel engines are commonly used heat engines in industrial and agricultural production. It is known that the efficiency of a certain model of diesel engine is 30%. Complete combustion of 2 kilograms of diesel in the diesel engine can release heat________J. This heat can be converted by the diesel engine to do useful work for the outside world________J . (The calorific value of diesel is 4.3×107J/kg)

Summary of this lesson

1. Calorific value:

①Concept: The amount of heat released when 1kg of a certain fuel is completely burned ②Unit: J/kg

③Formula: Q=mq

2. Boiler efficiency:

①Concept: The ratio of the energy converted into useful work by a heat engine to the energy released by complete combustion of the fuel

② Ways to improve boiler efficiency: reduce various energy losses

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For more information about the PPT courseware "Mechanical Energy Internal Energy and Its Conversion into Fuel Utilization and Environmental Protection", please click the Mechanical Energy Internal Energy and Its Conversion ppt Fuel Utilization and Environmental Protection ppt tag.

"Fuel Utilization and Environmental Protection" Mechanical energy, internal energy and their conversion PPT courseware 5:

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"Fuel Utilization and Environmental Protection" Mechanical energy, internal energy and their conversion PPT courseware 3:

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"Fuel Utilization and Environmental Protection" Mechanical energy, internal energy and their conversion PPT courseware 2:

"Fuel Utilization and Environmental Protection" Mechanical Energy, Internal Energy and Their Transformation PPT Courseware 2 Question: Do 1 kg of coal and 1 kg of liquefied petroleum gas generate the same amount of heat when burned? Which one releases more heat? Introduce the concept of calorific value, learn to look up the calorific value table, and become familiar with...

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Update Time: 2024-09-24

This template belongs to Physics courseware Beijing Normal University Ninth Grade Physics Volume 1 industry PPT template

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