The drafting unit of occupation standard
The deputy director of China Drying Equipment Industry Association
The airflow dryer operates on the principle of instantaneous drying. It utilizes the rapid movement of hot air to suspend wet materials in the air, thereby enhancing the entire drying process and increasing the rates of heat and mass transfer. After undergoing airflow drying, the non-bound moisture in the material can be almost completely removed (for example, the moisture content of materials like starch can be reduced from ≤40% at the inlet to 13.5% in the final product). The dried material does not deteriorate, and the output can be significantly higher than that of general dryers, allowing users to achieve higher economic benefits in a short period.
The first system is an ammonium sulfate crystal drying system. The entire process involves crystallizing ammonium sulfate solution in an MVR device, followed by centrifuging and then drying in this drying device. After drying, the material is packed into bulk bags. The drying device uses airflow drying, steam heating, and a bag filter for dust removal, and it includes bulk bag packaging. This system can dry ammonium sulfate crystals with a moisture content of 7% to below 0.5%, processing 1400 kg of material per hour. The process piping, fittings, and valve materials are made of 316L stainless steel, complying with American standard series pipelines and flange standards.
The second system is for drying ethylenediaminetetraacetic acid tetrasodium salt (NAX) filter cake. The process involves drying the wet filter cake material using an airflow dryer to remove its remaining moisture, followed by bulk bag packaging of the NAX solid. This system can dry NAX wet material with a moisture content of 30% to below 0.8%, processing 700 kg of material per hour. The control system uses DCS centralized control, allowing for fully automated control of temperature, liquid level, pressure, flow, and more. All rotating equipment can be started and stopped via DCS, with on-site start-stop capability for large rotating equipment such as fans and pumps.
1. High Drying Intensity and Low Equipment Investment: Airflow drying equipment has the highest processing capacity, with a moisture evaporation capacity ranging from 50 kg/h to 2000 kg/h. Despite the small equipment volume, it requires a low investment, making it incomparable to other drying equipment.
2. High Degree of Automation and Good Product Quality: Airflow drying processes the material entirely within the pipeline, with an extremely short drying time (only 0.5 to 2 seconds). Therefore, automation can be achieved, and the product does not come into contact with external contaminants, ensuring good quality.
3.Complete Equipment Supply and Flexible Heat Source Options:The basic setup consists of an air filter, heater, feeder, drying pipe, fan, and cyclone separator. Users can add dust collectors or other auxiliary equipment as needed.
4. Adaptable Heating Options: Airflow drying equipment offers great flexibility in heating methods. Depending on regional conditions, users can choose steam, electricity, thermal oil, or hot air furnace heating. According to the material's heat resistance temperature (or hot air temperature), the following can be selected:
- ≤150℃: Steam heating
- ≤200℃: Electric heating (or steam heating with electric compensation or thermal oil heating)
- ≤300℃: Coal-fired hot air furnace
- ≤600℃: Oil-fired hot air furnace
The short drying time makes it suitable for heat-sensitive materials, and since the final product does not come into contact with external environments, it ensures high quality.
5. Complete Equipment Provision with Various Heat Source Options: The heat source can be chosen between steam heating or the use of coal, oil, or gas-fired hot air furnaces.
6. Basic Airflow Drying Equipment: Suitable for loose, low-viscosity materials with granular and powdery end products. This process is depicted as negative pressure airflow drying, but users can choose positive pressure drying methods based on product characteristics.
