Resonant Acoustic Continuous Crystallizer for Safe and Tunable Recrystallization of Nitramines

Resodyn has developed the novel Resonant Acoustic Continuous Crystallizer (RACC) concept which is specifically configured for the recrystallization of energetic nitramines. This technology employs the Resonant Acoustic Mixing technology, which results in a uniform shear field throughout the mixing vessel. Radial mixing is accomplished to such a significant degree that true plug flow is achieved. Continuous recrystallization of nitramines such as RDX and HMX will result in increased process throughput, improved product quality and seamless scalability of the crystallization step from bench through production. The RACC process is inherently scalable since the mixing field is achieved without internal impellers or baffles and does not rely on high Reynold’s number or high shear rates to achieve mixing. The RACC technology employees a simple reactor design which has minimal pressure drop, even with increased crystal growth. The RACC concept is also highly amendable to employing Process Analytical Tools for Quality by Control. The independent process variables which will impact mean crystal size and particle size distribution width are adjustable by varying processing conditions, and do not require changes to reactor geometry or other difficult-to-adjust variables. The proposed Phase 1 project will demonstrate the RACC concept for the recrystallization of 2,6‐diaminopyrazine‐1‐oxide (DAPO) as a surrogate for energetic materials. A prototype RACC will be designed, built and demonstrated for the crystallization of DAPO. In order to demonstrate appropriate tunability and control of the process, the relationship between independent process variables on DAPO crystal size and particle size width distribution will be determined online using ultrasonic velocity measurement and verified with offline laser diffraction measurements. These results will be compared to recrystallization results using a classic stirred tank reactor design in order to quantify improvements in crystal production. The results of DAPO crystallization in the prototype RACC will illuminate the benefits of the technology and lay the foundation for pilot demonstration of RACC for the recrystallization of energetic materials in Phase II.