Are there conical reactor mixers also suitable for crystallising processes with precise temperature control?
Yes. Given a suitable design, cone reactor mixers can be used very well for crystallising processes with precise temperature control. They combine reactor and mixer and enable controlled management of chemical precipitation and crystal growth with a homogeneous temperature distribution in the product.
Constructional features for precise temperature control
For crystallisation processes, such plants are typically equipped with a double jacket for heating and cooling. Additional heat transfer surfaces on the mixing tool can enlarge the effective surface area and reduce temperature gradients in the product. Several separately controllable temperature zones support a defined heating or cooling regime.
Behaviour during phase change
Crystallisation processes often run through several phases, from the solution to the moist solid. Cone reactor mixers are designed to master these transitions gently and stably. Slow-running, high-torque mixing tools keep the product in motion and promote uniform crystal growth.
Use of vacuum and combined process management
Many cone reactor mixers can also be operated under vacuum. This is particularly helpful with thermolabile products, because solvents can evaporate at lower temperatures. Reaction, crystallisation and, where applicable, drying can thereby be combined in a single apparatus.
Process monitoring
For narrow requirements on the crystal size distribution, continuous process monitoring is advisable. Suitable measuring systems help to keep temperature, concentration and supersaturation in view. The mode of operation and the product quality can thereby be stabilised in a targeted manner.
amixon® vacuum mixer-dryers and synthesis reactors: mixing, reacting, crystallising and drying in a single apparatus
Two designs for integrated process management
The vertical mixer-dryer/reactor VMT and the cone mixer-dryer reactor AMT are of pressure-tight and vacuum-tight design. In the same apparatus, the processes of mixing, reacting, suspending, crystallising, de-agglomerating, coating, conditioning and vacuum contact drying can be combined. Process parameters such as system pressure, temperature, sequential addition of substances (dry, wet or gaseous) and mixing intensity are freely adjustable. Solid-state reactions and crystallising processes with precise temperature control are thereby covered as well.
Large heat transfer surfaces and short process times
The unique feature is that the entire mixing tool – shaft, arms and SinConcave®/SinConvex® helix – can also be fully temperature-controlled. Added to this is a large number of static mixing tools. Together with the double-walled mixing chamber, particularly large heat transfer surfaces arise. This enables rapid heat input and removal as well as extremely short drying times at low product temperatures. Cutting rotors accelerate mixing and drying and support de-agglomeration, for instance when passing through tough plastic phases.
Dead-space-free, safe, hygienic
The mixing chamber and the mixing tool are fully welded and ground. The mixing tool is mounted at the top only and the ball segment valve has few dead spaces and is vacuum-tight and pressure-tight. The mixing chamber is designed for ATEX Zone 20 and inerting is possible. On request, an FDA-compliant sterile reactor design, EHEDG certification, 3-A certification and steam sterilisability are possible. Materials up to Alloy 59 are available. The VMT 200 made of Alloy 59 serves as a reference; Hastelloy-C22 and nickel are also available. The sizes range from 100 to 50,000 litres in 100-litre increments. Low fill levels of, for example, 15 per cent are reliably possible.
The design is based on trials
Drying and reaction trials with the original product in the amixon® pilot plant, within the intended temperature and pressure range, provide the documented basis for the choice of apparatus and the dimensioning, even for large vacuum mixer-dryers. On request, amixon® supports customers with the thermodynamic extrapolation, in order to place the design on a robust footing.
Qualifiable and documented
For regulated environments, amixon® supplies qualifiable plants. Every apparatus is a one-off manufactured in accordance with the URS in its own production, with quality control that has no gaps. amixon® assists on request with DQ, IQ and OQ. Documentation and execution follow, on request, EU GMP and FDA 21 CFR Part 11.
On request the mixers meet relevant standards such as EHEDG, the FDA hygiene guidelines, the 3-A Sanitary Standards, USDA, GMP, ATEX and ASME. They are integrated into the operator's validation concept from the URS through to commissioning.