With the industrial innovation and the advance of science and technology, steam engine is replaced by gas-fired boiler that is a kind of more energy-saving heat production machine. There are three main usages of gas-fired boiler that we need to know in order to better understand the benefits that gas-fired boiler brings to us.
Here load means, amount of steam drawn from the boiler. So when the load increases, the specific volume of the steam in the boiler increases reducing the pressure. This inturn demands for more feed water and more amount of fuel to be burnt. So, for any boiler there will be a feed water level control system put in place to measure the water level in drum. As and when the level of water in the drum reduces, the controller sends a signal to the feed water pump to start and stops when the desired water level is reached. This way the steam generation continues to maintain the desired pressure.
The condensing boiler burns carbon-based fuel with oxygen in order to produce steam and carbon dioxide. The gases that escape this process (through a chimney) as exhaust are called flue gases. The major advantage is that they offer up to a 90% improvement in terms of efficiency when compared to standard gas boilers. Overall, condensing boilers are considered much more efficient in contrast to non-condensing gas boilers, a major consideration for any business running on a budget.
For same energy output when energy input is lesser efficiency increase. When maximum heat energy is generated from coal or losses in heat transfer are reduced efficiency increase. Coal in boulder size is burnt combustion may not be complete. There will be more unburnt coal. As per coal chemistry and as per boiler flue gas velocity as designed best coal size for full combustion is designed. Maximum crushed coal is also not the best. Then there will be more coal dust. According to general design in various technologies pulverized coal give best combustion for fbc boilers. For cfbc boilers generally crushed coal size is 6 mm.
When you achieve best combustion mean this is main contributor for increase in efficiency. Boiler design, heat transfer, flue gas velocity, heat losses, are other factors for efficiency.
Boiler efficiency is mainly depended on the amount of losses in the system. In high capacity pulverized coal fired boilers the total losses account to about 12 to 14%. Roughly 50% of the losses are governed by fuel properties like hydrogen in fuel, moisture in fuel and ambient air conditions. The other 50% losses are carbon loss and dry gas loss. The best efficiency in the boiler can be achieved if the losses are kept to the minimum. Since 50% of the losses are dependent on the fuel and ambient condition, the best efficiency can be achieved by properly tuning the other 50%, i.e. mainly carbon loss and dry gas loss.
The coal-fired steam boiler is a forced circulation high-pressure single-tube DC boiler. Its operation process includes three processes: the combustion process of the fuel, the heat transfer process of flue gas to water and the vaporization process after water absorbs heat. In order to better control these different processes, the control system should make
the heat of pulverized coal combustion adapt to the requirements of steam load changes and dryness.
1. The control system is equipped with a special computer controller, which makes the boiler running clear and easy to operate.
2. The burner is controlled by full-automatic program, and in case of failure, the burner stops automatically.
3. The boiler body is designed with reasonable structure, and the top is equipped with air vent. The boiler works under normal pressure and is far away from explosion danger. The full wet back three-way structure and corrugated tank design are adopted. The flue gas process is long, the temperature of exhaust gas is reduced, the heat transfer coefficient is increased, and the equipment life is prevented from being reduced due to the expansion and contraction of metal.
The coal-fired boiler refers to the boiler uses various types of coal as fuel and converts the heat of coal to steam or hot water.
There are generally two calculation methods of the circulating water volume of a coal-fired hot water boiler. One is to calculate the hourly water volume of one square meter and the other is to calculate the design parameter volume of every ton. As for the make-up water volume of this type of boiler, it is usually calculated as 1% to 3% of its total circulating water.
