A dryback boiler has a rear wall that is lined with refractory, a wetback boiler has a rear wall that is jacketed by water. Because of this fact, wetback boilers typically boast higher efficiency than dryback boilers as the heat from combustion goes directly into heating water instead of refractory. Wetback boilers are also more forgiving with load changes as the reversal chamber of the boiler is totally submerged in water creating an even heat transfer on the intermediate tube sheet to furnace joint.
The action of starting up a fire tube boiler for the first time is already a cold start. As a result, the mechanical load in this type of boiler is much greater, as the main characteristic of cold starts is the absence of boiling water and greater stress on the connection and anchorage elements of the boiler.
To make this start a bit easier for the boiler, the boiler operator should reduce the burner load to a boiling point.
Biomass steam boilers recover the heat generated during the biomass combustion process to heat the water in the boiler exchanger circuit. The hot water is then diverted to the heating circuit.
Occasionally it is necessary to remove the ashes generated by biomass combustion and clean the burner.
Steam carries about 540 Kcal/kg of useful energy whereas hot water and thermal fluid carry much less energy. Steam does not require a pump to transfer the energy. Generally, if the heating temperatures required are <100°C, then hot water can be used and if temperatures >180°C are needed then thermal fluid might be a better choice. For process temperatures between 100°C and 180°C steam is considered a viable option.
1. They are all a heat conversion device. The heat transfer medium they use is different. The water used in the steam boiler is heated to become steam. The heat transfer medium of thermal oil heater is heat medium oil. The heat is transferred to the heated substance by the heat medium oil.2. When a higher heating temperature is required, such as 280 degrees, the steam pressure of the steam boiler should reach 7MPa or more, and the process piping and heat exchange equipment must also withstand the same pressure. The equipment cost is high and dangerous. Thermal oil heater provides a temperature above 280 degrees, but the pressure is lower than 1MPa.3. The temperature of thermal oil heater can be accurately controlled within 3 degrees and the temperature of the steam changes greatly.4. Thermal oil heater is used alone, the exhaust gas temperature is higher, and the thermal efficiency is lower than that of the steam boiler. However, if used in conjunction with a steam boiler, the
Question details (Performance):1. The furnace wall at the coal economizer leaks water and steam with abnormal sound.2. The water level in the boiler drops sharply, and the water supply is obviously greater than the evaporation capacity.3. Smoke exhaust temperature and water outlet temperature rise.Answer: Fault reason:1. The water quality does not reach standard, and the oxygen in the water is decomposed into corroded pipe walls when the temperature rises.2. The low feed water temperature and smoke exhaust temperature make the inner and outer wall of the coal economizer pipe produce acid corrosion, or flying ash wear the pipe wall thin. 3. The pipe is blocked by impurities, causing overheating.4. Poor materials, defects in manufacturing, installation and maintenance. Troubleshooting:1. When economizer is slightly broke, it still maintains boiler operation, and the gap seems will not expand rapidly, in this case, load operation should be reduced, and start the spare boiler immediately,
