Process description of closed-loop belt dryer

The treatment of concentrated solution of drug residue (sludge) adopts direct drying method in traditional treatment process, such as spray drying, roller scraper drying, or direct drying of filter cake after pressure filtration, such as paddle dryer drying, rotary kiln drying, airflow drying, flash drying, or belt dryer drying. The above treatment methods all produce a large amount of wet waste gas containing organic matter and discharge it into the atmosphere during the drying process, which does not meet the environmental requirements. If the treatment of these waste gas requires a large amount of energy consumption and equipment input, and each link is open or semi closed, it cannot achieve continuous closed operation, and various leaks (material leakage, powder leakage, air leakage) will occur in each link, water leakage, etc.), also does not meet the requirements of energy conservation and environmental protection.

Based on material characteristics, processing requirements, and environmental protection requirements, after years of process transformation, exploration, and experience accumulation, we have designed a new set of processing technology: namely, using a closed screw press to continuously filter and concentrate the liquid, then entering a closed continuous extrusion granulator for granulation, and directly entering a closed-loop belt dryer for drying. The dried products of the closed-loop belt dryer are directly transported to packaging bags by a closed screw conveyor. The closed-loop belt dryer can be a low-temperature heat pump type full cycle multi-layer belt dryer or a medium temperature closed-loop multi-layer belt dryer. The entire processing is carried out during the sealing process, ensuring no gas emissions, no dust leakage, reliable equipment connections, compact equipment layout, simple production process, small footprint, low equipment investment, and energy conservation and environmental protection.

Process flow diagram of closed-loop belt dryer

Performance characteristics of closed-loop belt dryer products

1. It can fully achieve the "reduction, stabilization, harmlessness, and resource utilization" treatment of sludge, and the final sludge particles can be used as fertilizers, fuels, incineration, building materials, biofuels, landfill cover soil, land use, etc.

2. Adopting continuous mesh belt drying mode, suitable for various types of sludge drying systems (including sludge with high sand content), with a long service life.

3. The 80% moisture content sludge cake can be dried into 10% moisture content sludge particles; The sludge reduction capacity is 1/4-1/5, and the calorific value of urban sludge after drying can reach 3000 kcal/kg.

4. Low temperature (40-75 ℃) fully enclosed drying process, no exhaust emissions, no need for odor treatment system; The use of low-temperature drying can fully avoid the volatilization of different types of organic matter and odor gases in sludge, and will not cause secondary environmental pollution.

5. The system operates safely, with no explosion hazards and no need for nitrogen flushing; The oxygen content during the sludge drying process is less than 12%, the dust concentration is less than 60g/m3, the particle temperature is less than 70 ℃, and there is no dust during the entire drying process (air flow rate is less than 2 m/s).

6. The speed of the conveyor belt is controlled by frequency conversion, and the moisture content of the sludge discharge can be adjusted (10-30%) to meet the requirements of various types of processes.

7. Adopting the heat pump dehumidification technology, the comprehensive power consumption is 240kw. h/1t H20 (standard)

8. The equipment occupies a small area and is easy to install; The equipment occupies an area of approximately 3.5m2 for every 1000kg of water evaporated.

9. Adopting PLC+touch screen control system, fully automatic operation, convenient operation and management; Dry wet bulb temperature and humidity control, variable frequency control of feed rate, molding control, solid content control of discharge, material laying control, manual control, etc.

Application scope

Closed loop belt dryers can be used for industrial hazardous waste sludge and related materials, including electroplating sludge, leather sludge, biochemical sludge, petrochemical sludge, pharmaceutical sludge, pesticide sludge, feed sludge, biologics, pet feed, pet snacks, nickel containing sludge, copper containing sludge, lead containing sludge, tin containing sludge, heavy metal containing sludge, chromium containing sludge, cadmium containing sludge, hospital clinical waste wastewater treatment sludge, pesticide wastewater treatment sludge, wood anti-corrosion wastewater treatment sludge, cyanide containing sludge, sludge formed by alkaline or organic solvent cleaning and nourishing equipment, waste packaging wastewater treatment sludge containing dyes, pigments, inks, paint residues (dye and coating industry), production wastewater treatment sludge from organic resins, and wastewater treatment of photosensitive materials. Sludge Electroplating tank slag, tank solution, and water treatment sludge in the electroplating industry, corrosion solution, washing solution and sludge generated by acid (alkali) washing, oil removal, rust removal, and washing processes on metal and plastic surfaces, residue (liquid) and sludge generated during phosphating, light emission, and chemical throwing processes on metal and plastic surfaces, electroplating water treatment sludge, waste lead slag and lead-acid (sludge) generated in the production of lead (acid) batteries, waste lead slag and water treatment sludge in the lead casting industry, wastewater treatment sludge of organic phosphorus compound waste, wastewater treatment sludge of organic waste, wastewater treatment sludge of ether containing waste, and waste generated from the production, preparation, and use of halogenated organic solvents (water treatment sludge and waste carriers).