Dedert Corp. innovates process technology solutions across industries like starch, chemicals, food, biofuels and the emerging plant-based proteins market. For over 55 years, Dedert has been at the forefront of process technology initiatives with extensive experience and a specific expertise in drying and evaporation. Our customizations are a result of an holistic approach to Evaporation, Ring Drying, Flash Drying, and Spray Drying, and include opportunities to integrate different technologies to form optimized process solutions to lower the cost of operations and therefore provide easier access-to-market for new product innovations.
Spray drying is an historically well-known technology for liquid-to-powder drying, forming the subject of countless chapters in thermal drying textbooks. So, approaching customizations and innovations to spray dryers requires a thorough knowledge of the basic technology.
The heart of any spray drying system is the atomization system, and Dedert offers many different methods of atomization:
Rotary Atomizers: are comprised of a rotor and diffusion-impeller, driven by a direct-drive motor to impart rotational energy as the mode of atomization. Key advantages of rotary atomization include:
Innovations in this technology include the development of “bearingless” drives, such as magnetic-bearing technology, that do not require lubrication and thereby further improve serviceability and maintenance.
Pressure Nozzle Systems: require feeding by high-pressure piston pumps, effectively forcing the feed liquor into atomized droplets. Nozzle atomization allows uniformly fine particles within a narrow particle size distribution range with the following possible characteristics:
Dedert’s additional innovations include a specially-designed sanitary high-pressure valve system.
Two-Fluid Nozzles: comparatively to single-fluid nozzles that require an external high-pressure pump for feeding, two-fluid nozzles rely on atomization of the feed liquor by a secondary pressurized fluid to reduce operating and maintenance costs. Typical arrangements include the following:
Heated Atomization: is a specialty application for feed liquors that rapidly solidify in the absence of heat. Applications include processing of molten fatty or waxy materials, such as Polyethylene Glycol, into spray cooling systems.
Single-stage dryers and coolers produce simple powders using either rotary or spray nozzles in a 1-pass arrangement, i.e. without re-introduction of powders to the feed point for additional processing. Typically, spray chambers with nozzle atomization require tall spray towers to promote plug-flow and sufficient residence time. Comparatively, rotary atomizers have larger diameter but shorter vessels since the spiral flow characteristics provide the mixing turbulence required by efficient drying.
Dedert’s 2-stage and 3-stage spray dryers have similar drying characteristics within the spray chamber as single-stage dryers but include additional drying by discharging product into fluidized beds for the subsequent drying stages. These multi-stage systems can use the fluid beds to elutriate and recycle fines to produce agglomerated materials which are less dusty and can be more easily dissolved and dispersed into liquids. A 2-stage system contains only the external fluid bed, while a 3-stage system implements an internal fluid bed within the spray chamber discharge section.
For food and pharmaceutical products, the dryer layout can be zoned so that all the mechanical maintenance parts such as fans and filters are in a separate zone from the high-care production parts of the system that handle the high-value product.
In order to clean the dryer system, a full Clean-in-Place (CIP) system can be provided with a dedicated CIP kitchen, or designed to operate with a CIP system shared with the rest of the plant.
Spray chambers which experience many heating and cooling cycles are prone to cracking and must be regularly inspected to ensure that there are no areas for biological agents to accumulate. Dedert’ ultra-sanitary design additionally offers an Air Gap Insulation System which allows easy access to the drying chamber for inspection and repair if necessary. Rather than the typical method of insulating with cladded mineral wool, which needs to be removed and replaced at every inspection, high-care applications benefit from re-closable panel doors. The hinged easy-access doors are insulated to prevent heat losses, and open to allow visual inspection of all dryer surfaces. Additionally, in the closed position, an air-gap with high-insulating properties remains between the dryer surface and the doors and panels.
In addition to these process innovations, Dedert’s design initiatives also extend to personnel and infrastructure safety. Most dryer applications for Food and Pharmaceutical products process powders which can cause dust explosions. Venting or suppression systems on Dedert’s dryers are designed to comply with all ATEX or NFPA requirements, including proprietary sanitary and profiled vent panels and re-closable hinged explosion panels. Our safety systems also include installed deluge systems which would be activated in the remote chance of a fire in the system to protect personnel and equipment.
Dedert’s customized solutions improve production efficiency, process flexibility, and operational sustainability to help ease-of-operation while improving profitability. Let us help you to select, innovate, and design a tailor-made spray drying solution for your project, starting from Pilot Plant testing through to optimized for full-scale operation!
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