Stirling boiler is a stationary, externally fired, bent tube natural circulation water tube boiler. The Stirling boiler has steam generation rate up to50000 kg/hour and pressure rate up to 60 bar and a steam production of about. It has 60 to 80% efficiency.
This is one of the most commonly used boilers in the latest thermal power plants. In the thermal power, steam turbines are used for electricity production. The steam produced by the boiler is sent to the steam turbine. As the steam enters the turbine, it strikes the blades of the turbines and rotate the blade. The rotation of the blades further rotates the coal of the generator for electricity production.
Working of Stirling Boiler
A Stirling boiler works in the following way:
Water enters the third steam drum through the water inlet check valve and then through the elbow into the sludge tank. The particles settle in the sludge drum and are regularly expelled through the outlet valve. Therefore, the pure water passes through the elbow group to the other two drums. The steam drums are also connected to one another by pressure equalization pipes and circulation pipes. The circulation pipe equalizes the water level and the equalization pipe equalizes the steam level in the steam drum.
The combustion chamber is located in the lower left corner of the boiler and burns coal on the grate to create combustion gases.
The combustion gases are diverted through the brick arch and move up between the water pipes. There are baffles that direct the movement of the flue gases and ensure that the water pipes are properly heated. When it absorbs heat, the water flowing through the curved water pipe turns into steam. This steam moves upwards and collects in the steam drum above the water level.
The saturated steam is also taken from the second steam drum and fed to the overheated pipe. This converts the saturated steam into superheated steam, which can be discharged via the steam shut-off valve. The ash pit at the bottom of the boiler system collects the ash that arises when the fuel is burned in the ash pit and discharges it from the chimney into the environment. A flap is installed in front of the chimney to control the air supply to the combustion chamber.
Sterling boiler is a large water tube boiler system. Fixed use is acceptable, but mobile use is impractical except for large boats with moderate power requirements. They consist of a huge brick room with a winding airway through an almost vertical water pipe that winds between the drums of steam and water.
The hot gases from the furnace flow through each row in turn. Part of the firebrick tiles is placed in each group so that the gas flows up and then down in each group. Unusually, most of the airflow is along the axis of the tube and not through the tube.
All up and down cycles go through heat pipes and there are no separate external down pipes. However, the steam drum and the water drum are connected by a short horizontal pipe that is part of the circulation circuit.
The pipe itself is perfectly drawn steel, mostly straight and slightly bent at the ends. The boiler is built in as a large brick wall, but the steam drum is hung on the inside on another beam frame and expands with the heat. The hose and bucket, in turn, are suspended in a steam pail and can be freely inflated without forcing the ends of the hose. The curved tip of the aqueduct allows it to enter the drum radially and is easy to seal, but due to the epidemic of time and expansion, this was also a very important feature.
Advantages of Stirling Boiler
- The Stirling boiler has high steam generation rate.
- works under high pressure with very low pressure drop.
- It has flexible design.