Almost all other methods of drying, including using ovens, freeze dryers, or rotary evaporation, result in the mass of irregularly sized and shaped granular materials that require further processing (such as grinding and filtering). On the other hand, spray drying provides very flexible control over properties beyond powder particles, such as density, size, flow characteristics, and moisture content. The drying of spray drying equipment includes the following stages:
1. Feed preparation: Mold pipeline cleaning machine This can be a uniform, pumpable, and impurity free solution, suspension, or paste.
2. Atomization (converting feed into droplets): a crucial step in this process. The degree of atomization controls the drying rate, therefore, the size of the dryer. The more commonly used atomization techniques are:
a. Pressure nozzle atomization:High temperature mold temperature machineSpray forces fluid to create through a small hole. This is an energy-saving method that also provides a narrow particle size distribution.
b. Two fluid nozzle atomization: spray is produced by mixing raw materials and compressed gas. A more energy-efficient method. Can be used to make extremely fine particles.
c. Centrifugal atomization: Spray is created by feeding or rotating the disc. Wear resistant and can generally operate for longer periods of time.
3. Drying: A constant rate stage ensures rapid evaporation of moisture from the surface of the particles. Afterwards, the drying process is controlled by water diffusion to control the rate of decrease on the surface of the particles.
4. Separation of wet gas powder: In order to achieve economic efficiency (such as recycling dry media) and pollution-free methods. Fine particles are usually removed by cyclone separators, bag filters, dust collectors, or scrubbers.
5. Cooling and packaging.
Therefore, a control system must provide flexibility in the way that accurate and repeatable control of spray drying equipment can be achieved, and will include the following features:
a, Programming precise closed-loop control within the set value range
b, Easy to parameterize formula management system
c, Sequential control complex control strategy
d, The secure collection of online data is analyzed and evidenced from the system
e, Clear graphics and controlled access parameters displayed by local operators.