1、 Overview
The disc blade dryer has now developed into a relatively mature drying process. The process flow of semi drying and incineration of sludge in the disc dryer is as follows: the wet sludge entering the sludge treatment plant is pumped into the sludge dryer by the sludge pump. The sludge in the dryer is heated indirectly and evaporated to produce water. The evaporated waste steam is condensed into liquid by the condenser and treated to meet the standard before being discharged or included in the sewage pipe network. The dried sludge enters the incinerator for incineration. The high-temperature flue gas generated by sludge incineration is recovered by the waste heat boiler, economizer, and air preheater, and then treated by the tail gas purification device to meet the standard before being discharged into the atmosphere through the chimney. The heat energy recovered by the disc dryer generates steam or heats the conductive oil, which serves as the heat source medium for the dryer to achieve effective utilization of heat.
2、 Process conditions:
Material: Bean dregs
Initial moisture content: 65% (alcohol)
Final moisture content: 20% (wet basis)
Dry product yield: 1750Kg/h
Dry particle size: 40-80 mesh
Dry product stacking density: 0.8g/cm3
Drying temperature: 150-160 ℃
Heating method: steam
Recycling: Host
Equipment material: 304 at the material contact point, and A3 steel painted for the rest
Installation: Indoor
Power supply: 380V 50HZ
Environment: 20 ℃ 760mmHg Relative humidity φ=80%
3、 Principle:
The material enters the dryer through the feeding port, and the honeycomb jacket and hollow hot shaft of the dryer are both filled with heating medium. Through the heat conduction of the jacket wall and hot shaft, the wet material is indirectly heated and dried; The dryer body tilts, with a tilt angle of 0.5-1.0 ° from the feed to the discharge as a whole. Solid materials gradually move towards the discharge port under the stirring of gravity, blades, and sheet materials. Under the continuous stirring of various scrapers, the wet material in the dryer constantly updates its heating interface, and is fully and uniformly heated after coming into contact with the inner wall of the cylinder and the heating disk. The large amount of steam generated during drying is pumped by the vacuum pump through the induced draft duct to the tube condenser, where it exchanges heat with the cooling circulating water in the heat exchange tube of the tube condenser. A large amount of exhaust gas releases heat and is converted into exhaust gas condensate, which is pumped out of the machine by the condensate pump and enters the sewage tank for centralized treatment.
4、 Application:
This disc dryer can be applied to both semi drying and fully drying processes; Multiple heat transfer media such as steam and thermal oil can be used, and the on-site environment is very good.
5、 Characteristics
1. The blade shaft is a hollow seamless thick walled tube, with a steam inlet at one end and a condensate outlet at the other end. Several blade components are arranged in parallel on the shaft;
2. The blade assembly includes a hollow disc blade, which is welded in series on a hollow shaft. Each blade is equipped with a scraper on its outer surface, and a steam inlet pipe is provided inside the blade. Each steam inlet pipe is connected to the hollow shaft, and a condensate outlet pipe is provided at the position where each blade is connected to the hollow shaft. Each condensate outlet pipe is connected to the hollow shaft; The blade and scraper are perpendicular to each other. The end of the steam inlet pipe near the hollow shaft extends into the interior of the hollow shaft, while the end of the condensate outlet pipe near the blade does not extend into the interior of the blade;
3. The sealing structure set at both ends of the hollow shaft adopts a dual sealing form of packing seal and cylinder seal. In the sealing component, the packing seal is located near the end of the cylinder, and a cylinder is set at each end of the outer side of the packing cover. Since the cylinder is always in working condition, it can continuously apply pressure to the packing, keep the packing in a compressed state, and keep the interior of the cylinder in a vacuum state, which can eliminate the gap formed between the hollow shaft and the packing due to rotation and ensure reliable sealing. This ensures the required vacuum level inside the vacuum disc blade dryer during operation. Since the equipment can only be fed in and out under normal pressure, it also guarantees the continuous production of the equipment, solving the problem of the existing vacuum rake dryer being unable to continuously vacuum and produce.
4. Two rows of concentric disc blades are evenly arranged on the hollow shaft of the hollow disc blade dryer. The hollow shaft and blades are both hollow structures, and heating medium can be introduced into their interiors. Steam enters from the steam inlet end of the hollow shaft and then enters each blade through the steam inlet pipe. The condensed water in the blades is collected in the hollow shaft and discharged from its condensed water outlet. During this process, the material is heated in the vacuum continuous dryer due to the heat transferred by the blades and the inner wall of the cylinder, and is stirred under the rotation of the blades and the scraper on them before being discharged from the discharge port. Due to the fact that steam can be introduced into both the hollow shaft and the blade, the single shaft blade vacuum continuous dryer increases the heat transfer area per unit volume, shortens the drying time, increases output, and reduces production costs.
