Which manufacturer’s spray drying equipment is good?

Micro spray dryer Abstract: This paper introduces the working principle, structural design, and performance parameters of a micro spray dryer specifically developed for laboratory use. This model features a small size, low energy consumption, simple operation and control, and ease of movement and cleaning. 1 Overview: Spray drying is a process in which the liquid material to be dried is atomized into extremely small droplets using an atomizer; these droplets then undergo thorough heat and mass exchange with hot air acting as a heat source, thereby removing moisture and achieving drying. It is an ideal drying method for processing materials such as solutions, suspensions, and emulsions. Currently, the spray drying equipment available for testing in China is mainly centrifugal spray dryers or air-flow spray dryers. Commonly used specifications include centrifugal spray dryers with diameters of ~800mm, ~1000mm, and ~1250mm, as well as air-flow spray dryers with a diameter of ~500mm. Although the aforementioned equipment is a pilot-scale testing unit, it has drawbacks such as a large size, difficulty in moving and cleaning, high overall power consumption, and high material consumption during the testing process. In light of the current situation in China, a miniature spray dryer for laboratory use is introduced – one that is small in size, handles small volumes of liquid material, and is easy to move and clean. This dryer has passed the evaluation conducted by the Jinan High-Tech Development Zone in 2005, filling a gap in this field in China. 2 Working Principle: Taking into account the need for a compact design and compatibility with the materials to be tested, this device uses an air-flow-based atomization method. The process flow is shown in Figure 1. The compressed air supplied by the air compressor is ejected at high speed from the nozzle. The liquid material to be dried is pumped to the airflow nozzle using a peristaltic pump, and thanks to the speed difference between the compressed air at the nozzle and the liquid material, the liquid is atomized into countless tiny droplets. Under the action of the exhaust fan, natural air is heated by an electric heater and then enters the agricultural product drying chamber through a air distributor. There, it comes into full contact with the liquid droplets in the material, allowing for rapid heat and mass exchange; this process enables moisture to be removed in a very short time, turning the raw materials into powdered products. Larger particles are collected by a collection cylinder, while most of the finer powders are separated using a glass cyclone separator and then collected in a collection cup. The exhaust gas is discharged through an exhaust fan. 3 Structure The structure of the micro spray dryer is shown in Figure 2. 3.1 Air flow nozzle: A two-fluid air flow nozzle of the external mixing type is used, with the nozzle tip connected to the nozzle body via threads. To accommodate different material properties and drying requirements, the nozzle tip comes in three sizes: 0.5 mm, 0.7 mm, and 0.8 mm. The connection between the nozzle tip and the nozzle body is interchangeable, allowing the nozzle tip to be replaced as needed. 3.2 Drying Vessel: To facilitate observation during the testing process, the drying cylinder, cyclone separator, collection cylinder, collection cup, and connecting pipes are all made of borosilicate glass suitable for boiling at 300°C. 3.3 Heat source: By determining the heat required by the system, an electric heater with a power of 2.5 kW is used as the heat source. By using a thyristor for voltage regulation, the power can be varied between (0–2.5) kW, and interlocked control is achieved with the inlet air temperature. In use, the power of the electric heater is automatically adjusted according to the preset inlet air temperature. 3.4 Air Distributor: Through the analysis and study of the drying mechanism, a unique air distribution structure suitable for micro spray dryers was designed. This structure effectively prevents the raw material droplets from sticking to the walls, while also ensuring thorough contact between the hot air and the droplets, thereby enabling rapid heat exchange and achieving high thermal efficiency. 3.5 Frame: The various components of the dryer are arranged logically and all mounted on the frame; the entire drying system forms a cohesive unit with a compact and attractive design. Four casters are installed at its bottom to facilitate movement. 3.6 Automatic Control: The operating parameters of this machine, such as the inlet and outlet air temperatures, the amount of liquid feed, the flow rate and pressure of compressed air, as well as the system air volume, can all be easily controlled and adjusted, thus fully meeting the requirements of variable experimental conditions. The methods for measuring and adjusting each parameter are shown in Table 1. 4 Technical parameters: The main technical parameters of the micro spray dryer are shown in Table 2. 5 Adaptability tests: As a testing device, it is required to achieve satisfactory drying results for various liquid materials with different physical properties, that is, to meet the need for handling a wide range of material types. We selected several typical materials with different properties as representatives for air flow drying tests; the test parameters and results are shown in Table 3. As shown in Table 3, this micro spray dryer can achieve good drying results for a variety of materials with different states, initial moisture contents, and viscosities, indicating that the equipment has good adaptability to various materials. 6 Conclusion (1) This device uses air jet atomization, which effectively reduces the volume of the drying chamber; only (300–600) ml/h of liquid material is required for testing. This approach can **reduce testing costs** for expensive pharmaceuticals and biochemical products. (2) Tests have shown that this device exhibits good adaptability to liquid materials with various physical properties, making it an ideal miniature testing device.

The spray drying process at Shanghai Chemical Machinery Plant No. 3 is also feasible

Shanghai Dachuanyuan Drying Equipment Co., Ltd