Alhaleeb Mustafi A, Machin Nesrin E
Department of Chemical Engineering and Applied Chemistry, Atılım University, Ankara, Turkey.
Heliyon. 2020 Sep 21;6(9):e04840. doi: 10.1016/j.heliyon.2020.e04840. eCollection 2020 Sep.
The most critical part of the flame spray pyrolysis (FSP) process is the nozzle, since it plays a key role in setting the spray properties. In this study, we developed an approach to adjust the nozzle throat gap size for a desired dispersion gas flow rate and upstream pressure, based on the external size and shape of a two phase external mixing nozzle. An equation was derived and validated by comparing the predicted gas flow rates with the data provided in a commercial nozzle supplier chart. Experiments were also conducted in our lab-scale FSP reactor to test the validity of the predictions. The approach developed here was found to closely predict the gap size necessary to pass the required dispersion gas flow at a desired pressure drop. Error in predictions was found to be less than 3% at an upstream pressure range of 3-10 bars. The isentropic flow assumption for perfect gases across the convergent-divergent nozzle was found to fail below 2 bars, consistent with the theory applied. By using the method here, the nozzle setting for a desired operation in an FSP process can be easily done, minimizing the time-consuming trial and error steps needed otherwise.
火焰喷雾热解（FSP）过程中最关键的部分是喷嘴，因为它在设定喷雾特性方面起着关键作用。在本研究中，我们基于两相外部混合喷嘴的外部尺寸和形状，开发了一种方法来调整喷嘴喉部间隙尺寸，以实现所需的分散气体流速和上游压力。通过将预测的气体流速与商业喷嘴供应商图表中提供的数据进行比较，推导并验证了一个方程。我们还在实验室规模的FSP反应器中进行了实验，以测试预测的有效性。结果发现，这里开发的方法能够紧密预测在所需压力降下通过所需分散气体流速所需的间隙尺寸。在上游压力范围为3 - 10巴时，预测误差小于3%。发现在收敛 - 发散喷嘴中，低于2巴时理想气体的等熵流假设不成立，这与应用的理论一致。通过使用这里的方法，可以轻松完成FSP过程中所需操作的喷嘴设置，最大限度地减少了原本所需的耗时试错步骤。
