Sludge
1. Material Overview
It is sediment discharged from wastewater treatment plant. The organic matter mainly composed of sediment is called sludge. It is characterized by easy putrefaction and odor, fine particles, low specific gravity (approximately 1.02–1.006), high moisture content and difficulty in dehydration, and it is a hydrophilic substance with a colloidal structure.
Sludge can be divided into (1) water supply plant sludge: originating from the purification process of water supply sources; (2) domestic sewage sludge: originating from the process of treating domestic sewage in urban sewage treatment plants; (3) industrial sludge: originating from the process of treating industrial wastewater in sewage treatment plants; (4) urban water body dredging sludge originating from the dredging process of natural or artificial water bodies such as rivers, lakes, and ponds.
2. Process Introduction
Wet sludge is continuously fed into the paddle dryer. Under the stirring action of two heated shafts and interlaced hollow heat-conducting blades inside the dryer, the wet sludge exchanges heat with the shafts and blades in full contact. Simultaneously, it is gradually conveyed towards outlet by the blades. An overflow baffle is provided at the tail end of the dryer, allowing the dried material to overflow and discharge. The paddle dryer casing has a jacketed structure, providing a continuous source of heat for drying. The residence time of the material can be controlled by adjusting the motor frequency and the height of the weir plate, thereby controlling the drying capacity and the final moisture content of the material within a suitable range.
3. Technical Advantages
1) High-efficiency heat transfer + anti-sticking structure
It adopts dual heating with jacket + blade conduction heat transfer as the main method and hot air convection as the auxiliary method, which has a high heat utilization rate; the blade rotation scraping wall design completely avoids material sticking to the wall and forming scars; the parts in contact with the material are stainless steel polished to reduce residue and pollution; it has excellent sealing performance and low material loss.
2) Precise self-control + continuous operation
Integrated PLC full-process automation control allows for flexible adjustment of blade speed, steam pressure, and feed quantity, while providing real-time monitoring of temperature and moisture content within the cylinder. The temperature control accuracy reaches ±3℃, ensuring stable operation and adaptability to large-scale continuous production.
3) Low energy consumption and environmental protection
Closed operation reduces dust leakage, and a simple dust removal system can meet environmental emission standards;
No large amount of hot air is required, the exhaust gas treatment load is low, and the investment and operation and maintenance costs of environmental protection equipment are saved.
4. Technical Benefit
1) Investment cost
The equipment has a compact structure and occupies a small area, with lower civil works and installation costs. The environmental protection treatment system is simple, and the overall project investment is controllable, suitable for small to medium-sized production capacities as well as large-scale production needs.
2) Optimized operating energy consumption
High efficiency in heat transfer, resulting in a 20%-30% reduction in steam consumption compared to conventional hot-air drying; no need for high-power fans, significantly lower power consumption than airflow drying equipment, and substantial savings in steam and electricity costs.
3) Reliable product quality
The anti-stick wall design reduces material residue and contamination, ensuring product purity; gentle drying avoids thermal degradation of materials, maintaining the original performance and appearance of the product, meeting high industry standards and enhancing market competitiveness.
4) Easy operation and maintenance
Paddle scraping reduces manual cleaning with fewer wearing parts, simple maintenance, short downtime, ensuring production continuity and OPEX costs.