Back to case study overview
Circular Divider

Drying of chemical compounds in solution or suspension

Circular Divider

An introduction to this case study

Drying stands as a pivotal process for the production of high-purity powders derived from chemical compounds in solution or suspension. Examples of such compounds encompass calcium carbonate, aluminum hydroxide, calcium nitrate, magnesium sulfate, magnesium carbonate, copper sulfate, dicalcium phosphate, ammonium sulfate and phosphate, calcium carbonate and phosphate, as well as boric and adipic acids, among others.

Among the various techniques available, spray drying emerges as the predominant method for converting these chemical compound solutions or suspensions into fine powders. However, when compared to spray drying, pulse combustion drying consistently yields superior powders in terms of particle morphology, size, and powder flowability.

Technologies used in this case study:


Look at how we deal with the followingchallenge:

1. Drying of chemical compounds in solution or suspension

Drying of chemical compounds in solution or suspension


In industrial processes, powders are often preferred to possess spherical particles with a narrow size distribution and controllable morphology. This applies both to their use as raw materials in production and as final products, where particle size plays a crucial role.

The major challenge associated with spray drying lies in the unpredictability of powder particle morphology post-drying. It can result in undesirable forms, such as hollow or toroidal-like spheres, or even doughnut-shaped particles. Furthermore, in certain medical applications, the requirement for powders with submicron particles exceeds the capabilities of spray drying.


Sinowatek's advanced pulse combustion drying technology offers a solution that surpasses spray drying in multiple aspects. The powders produced are superior due to their predictable formation of smooth, spherical solid particles, submicron-sized particles, a narrow particle size distribution, and excellent powder flowability.

These superior properties arise from gas-dynamic atomization occurring at the top of the drying chamber. Here, a low-pressure, slow-moving liquid solution or suspension is introduced through a single pipe into a pulsating, high-velocity gas stream. Within milliseconds, this process forms ultra-fine (5-50μm) droplets while converting the surface moisture into superheated steam. The result is a dry, fine powder with spherical and smooth surface particles. The energy absorbed by the evaporating water and the extremely short time the solids are exposed to the heat source, ensure the preservation of the characteristics of the solids.

Benefits for clients:

  • Energy consumption for PCD dryers stands at 1.15 kW/kg water evaporated (thermal and electric). In contrast, studies indicate that spray drying processes can consume as much as 2.3 kW/kg (equivalent to 8.4 GJ/metric ton). Pulse Combustion Dryers demand less air, resulting in smaller drying chambers and reduced electrical consumption for smaller fans. With simple product injectors and smaller fans, running costs are 20-30% lower than those of spray driers.
  • Unlike spray dryers, the PCD boasts an atomization nozzle that essentially functions as an open pipe, eliminating concerns about wear and tear affecting atomization dynamics.
  • The PCD employs no high-pressure pumps or high-RPM equipment, resulting in lower maintenance requirements compared to its competitors.
  • Smaller air volumes, lower pressure for mixture delivery, and a more compact equipment footprint collectively make the process more cost-effective than traditional spray drying methods.
  • Sinowatek's Pulse Combustion Dryer (PCD) Test Centre offers the capability to dry any chemical compound in solution or suspension for suitability and compatibility assessments with the drying method. This process also validates energy consumption and product quality parameters, guiding the design and construction of scaled-up production PCD units.
  • For low-volume toll processing needs, we provide access to our PC Dryer at the PCD test centre, facilitating the drying of high-value, high-purity products.

Let's talk  about your specific challenges in this field.