Hollow ceramic mugs What is the value? What is the value? What are the differences?

Hollow ceramic mugs

Fuel the moisture contained in the hydrogen element (including free water and bound water), the water vapor formed in the combustion and a fuel after combustion into steam (2H2 + O2 = 2H2O steam), if the condensation down, can be released some of the heat (which we call the heat of condensation). Calculating the calorific value of the fuel, if this part of the heat added to calculate the value of the calorific value is bound to be bigger. The so-called high heating value is calculated from the calorific value in the case is assumed that the complete condensation of the water vapor in the flue gas in the 0 ° C water. But in practice, the furnace flue gas temperature is very high, the tunnel kiln, the flue gas temperature of 200 ℃. In this case, water vapor is not condensed into a 0 ° C water. Therefore, in the actual work, the calculation of the calorific value of the fuel, only assume that all water vapor in the flue gas is cooled to 20 ° C the water vapor, so that counted out the heat value is known as the LHV. Thermal calculations, generally using low calorific value, because it is more in line with the actual situation; while high calorific value, is generally used in the course of scientific.

It can be seen, the difference between the high calorific value and low calorific value lies in a 20 ° C water vapor into a 0 ° C water of this part of the heat. To calculate the part of the heat, it must calculate the water generated in the combustion of fuel is the total number.

Example below coal

Set 100 kg of coal containing H kg hydrogen, then the water produced when it burns 9H kg, namely:

2 H2 + O2 = 2 H2O

4 (kg) 36 (kg)

H (kg) x (kg)

Was 4:36 = H: x

x = 36H / 4 = 9H (kg)

Set 100 kg of coal itself moisture contained (including free water, bound water) w kg, so that the total amount of water generated by coal combustion: (w +9 H) kg.

Scientific experiment tells us: one kilogram of water vapor condensation from 20 ℃ to 0 ° C liquid water, the heat released is about 600 kcal, so (w +9 H) kg of water vapor condensation from 20 ℃ to 0 ° C liquid water the heat released as follows:

600 (w +9 H) kcal

Thus, we can know the total amount of water generated upon combustion of 1 kg of coal (W +9 H) / kg, and 100 by 20 ° C the water vapor condensate to the heat released when the 0 ° C water should be :

600 (W +9 H) / 100 = 6 (w +9 H) kcal

This tells us that the high calorific value Q high and low calorific value Q difference:

High Q-Q = 6 (w-9H) kcal / kg