The main idea of this project is the production of powder detergent by spraying dryer technology. A comparison between powder produced from spray dryer method (tower technology) and powder produced from an agglomeration process (non tower technology) was carried out, for justification of the feasibility of the spray tower.
Parameters and operating conditions of both techniques were studied theoretically. These include temperature, pressure, type of nozzle, and the behavior of flow (co-current or counter current).
The selected technique in our project was the countercurrent spray drying process, since it the commercial industrial type. Powder produced from spray dryer tower was found to be more acceptable, because the residence time of drying the slurry was less than other technique.
After that the powder produced was tested to satisfy the standard specifications of the powder detergent. These tests that needed to assess the powder quality were density, bulk density, pH and moisture content.
The evaporation rate was found to be the major design parameter in spray drying process, and the other parameters design were determined depending on the evaporation rate.
Therefore as the following basis, the evaporation rate was calculated (These calculations depends on the industrial information). These basis are:
The inlet moisture content of the slurry was 40% at temperature 25 ºC, and the feed rate was 50 kg/h. At exit the moisture content was reduced to 4% and temperature was raised to 60 ºC. The hot air inlet temperature 250 ºC and the velocity of air 0.3 m /s. So, the evaporation rate was found to be , and the drying time was 97 s.
The following findings were found for spray dryer: the density was found to be 0.65 g/ml, the bulk density was 0.55 g/ml, pH was 10.5 and the moisture content was 10%. These were in acceptable range with respect to commercial powder production.