Comparison and explanation of scraper blade and propeller agitator of single axis disc sludge dryer:
1. Both the hollow blade dryer and the single axis disc sludge dryer have been put into operation for a long time and are relatively mature;
2. The working principle is very similar. The shell is hollow with a jacket, a hollow shaft, and hollow blades (discs), which belong to pressure vessels and are all indirect heating and drying equipment;
3. Both jacket heating can be designed as coil or honeycomb type
4. During the implementation of the project, the external access requirements are basically the same, except for slight differences in the external dimensions of the equipment, which can be replaced with each other in the sludge drying project;
5. Adaptability of viscous sludge.
The blade shaped blade has a cutting effect on sludge, so this equipment has a certain self-cleaning function for sludge with low viscosity. However, for sludge with strong viscosity, due to the uneven cross-section of the blade, a scraper cannot be used, which will cause sludge to adhere to the drying surface and affect the drying effect and equipment drying capacity; The disc of the disc dryer has no cutting force on the sludge, but it is equipped with a scraper blade, which can fully adapt to high viscosity sludge. The maintenance and even replacement of the scraper blade are convenient and cost-effective;
6. Wear resistance and safety. Some sludge has a high sediment content, so equipment selection should fully consider wear resistance. The hollow cylindrical blade of the blade dryer is a pressure vessel with an internal pressure of 0.3-1.3MP and is a structural component of the equipment. Due to its cutting effect on sludge, running for a period of time will inevitably lead to wear and tear, resulting in leakage of thermal oil or steam (if thermal oil is used as a heat source, it may cause safety accidents!), thereby increasing equipment maintenance costs, reducing operating time and service life; As a pressure vessel, the disc of the disc dryer is also a structural component with an internal pressure of 0.3-1.3MP. The disc has no cutting force on the sludge, so it is not easy to wear out. The pushing and stirring of the sludge rely on the pushing agitator at the edge of the disc. The disc type sludge dryer not only solves the problems of high sediment content and wear in sludge, but also plays a huge role in covering sludge, urban household waste, and sewage treatment; Its equipment price is significantly lower than that of foreign drying equipment; The disc type sludge dryer increases the equipment selectivity for sludge disposal technology.
The main body of the disc sludge dryer is mainly composed of a stator, a rotor, and a driving device. The sludge is fed into the dryer through the feeding port, and the working medium flows between the shell and the hollow shaft. Heat is transmitted through the jacket, hollow shaft, and hollow disc welded on the shaft. The sludge is indirectly heated and dried, and the generated water vapor accumulates in the dome of the dryer and is extracted from the dryer. The hollow disc is basically perpendicular to the shaft and has no pushing force on the sludge. Through the pushing/stirring effect of the disc edge, the sludge is stirred and the drying surface is continuously updated to achieve the purpose of drying.
The disc type sludge drying technology is different from traditional drying technology. It adopts the principle of indirect drying and uses 0.2Mpa to 0.6Mpa medium low pressure saturated steam as the working medium to achieve sludge drying treatment in the disc type dryer. During operation, the oxygen content and dust concentration are low, and the system safety is good.
