SCALE-UP APPROACHES FOR THE ADN-PRILLING PROCESS BY EMULSION CRYSTALLIZATION

摘要

The history of ammonium dinitramide (ADN) over the last fifteen years shows a consistent development from research product to propellant applications. Nowadays ADN is the most hopeful candidate to replace ammonium perchlorate in solid rocket propellants. Currently ADN seems to stand at the border to industrial use. European research projects like the FP7 project HISP (High performance solid propellants for In-Space Propulsion) and the follow-up Horizon 2020 project GRAIL (Green Advanced High Energy Propellants for Launcher) are indicating this trend. The application of ADN in propellant formulations requires spherical particles, so-called ADN-Prills. Two alternative routes for producing these ADN-Prills were investigated by FOI and Fraunhofer-ICT. The emulsion crystallization process developed by ICT has a batch size of 500 g. The testing of ADN propellants in technical scale needs the supply with increasing amounts of high quality intermediate products like ADN-Prills. Consequently, approaches were made to scale up the emulsion crystallization process for ADN-Prilling. The concept is to create a continuous process step by step. Therefore the heating and emulsifying sub-processes were realized by a tubular heat exchanger. Pumping rates of 12 I high viscous ADN-emulsion per hour could be achieved while keeping the desired process temperatures. This has the potential to produce 2 kg ADN-Prills per hour.