High and low calorific values of fuel
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What are the high and low calorific values of fuel? What are reasonable values to use in practical applications? Answer: The heat released when fuel burns completely and the water produced is in vapor form is called the low calorific value of the fuel. The heat released when fuel burns completely and the resulting water is in liquid form is known as the high calorific value of the fuel. In practical applications, it is reasonable to use the lower calorific value, as water is generally in a gaseous state at the actual flue gas temperature. . Please help explain this question in more detail – what does it mean for the water generated to be in a vapor state, and what does it mean for it to be in a liquid state?
Think about it: to produce water, latent heat must be released as well, so the heat generated is greater; literally speaking, this is what’s meant by a high calorific value!
What do you mean by high calorific value and low calorific value? I’ve never heard of it. If you’re talking about high calorific value or low calorific value, then I know what those are
I haven’t heard of high and low calorific values either. I have only heard of the terms high calorific value and low calorific value.
Think about it: to produce water, latent heat must be released as well, so the heat generated is greater; literally speaking, this is what’s meant by a high calorific value! Well written
Another answer: Taking fuel and gas as an example, the high-calorific value = low-calorific value + the recoverable condensation heat. For natural gas: 9000 Kcal/Nm3 = 8400 + 600. Is this explanation clear? The same as other fuels!
Generally, low calorific value ones are used, right?
High calorific value: (theoretical heat value) It refers to the heat released when the ignition temperature of the fuel combustion and the final temperature of the combustion products are both set at 15°C, with the water produced as a result of complete combustion being in liquid form. Low calorific value: (net calorific value) The starting and ending temperatures of combustion are 15°C, and the water produced is in gaseous form. The difference between the high and low calorific values is the latent heat of vaporization of water at a saturated vapor pressure of 15°C. A low calorific value is used in engineering calculations (because in actual combustion, the temperature of the exhaust gases exiting the flue is much higher than that of the water vapor; the water does not condense and remains in the form of vapor). The values found in reference books correspond to the complete combustion of oil. Calculation of the low calorific value of fuel: QL=81C+246H+26*(S-O)-6W. Where C, H, S, O, and W represent the mass percentages of carbon, hydrogen, sulfur, oxygen, and water in the fuel, respectively
In practical applications, it is reasonable to use the lower calorific value, as water is generally in a gaseous state at the actual flue gas temperature. . Please help explain this question in more detail – what does it mean for the water generated to be in a vapor state, and what does it mean for it to be in a liquid state? -------------------------------------------------------------------------------------------------------------- In the furnace, the flue gas temperature is always above 100°C; since this is higher than the boiling point of water, it is in gaseous state, whereas it is in liquid state otherwise