Low Heat Spray Drying via Electrostatic Atomization
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Solution Overview
Problem
Conventional spray drying processes degrade active ingredients due to high temperatures, leading to undesirable modifications such as evaporation and oxidation, which result in reduced performance and revenue loss, especially in the pharmaceutical and flavor industries.
Innovation Solution
The method involves forming a slurry with a liquid solvent and active ingredient, applying an electrostatic charge to the slurry, and atomizing it to produce charged particles, which are then suspended in a non-heated drying environment to drive off the solvent without heat, using a non-heated drying fluid and potentially dehumidified air, and electric fields to guide particles through the drying chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature heated air is used for spray drying, then drying efficiency is improved, but active ingredients are degraded through evaporation and oxidation
Solution Approach 1:
The invention changes the temperature parameter from conventional high temperature (180-200°C) to low temperature (below 100°C, preferably 20-80°C). This parameter change enables drying to proceed at temperatures insufficient to cause significant degradation of active ingredients, while still achieving acceptable drying rates through the combined effects of atomization, low humidity air, and extended residence time
Solution Approach 2:
The invention applies preliminary action by pre-cooling the drying air and pre-atomizing the slurry into fine droplets before introduction to the drying chamber. The slurry is atomized to create extremely small droplets with high surface area to volume ratio, which accelerates evaporation at low temperatures. The drying air is pre-cooled and dehumidified to create optimal conditions for low-temperature drying
2Object-affected harmful factors
If low temperature drying is used, then active ingredients are preserved, but drying time increases
Solution Approach 1:
The invention applies segmentation by dividing the slurry into extremely fine droplets through atomization. This segmentation creates billions of tiny droplets per unit volume, each with high surface area to volume ratio. The increased total surface area dramatically accelerates the evaporation rate, compensating for the lower temperature driving force and reducing overall drying time
Solution Approach 2:
The invention transitions from bulk liquid drying to droplet aerosol drying. By atomizing the slurry into fine droplets and suspending them in a large volume of drying chamber, the process moves from a three-dimensional bulk phase transformation to a dispersed phase process with vastly increased surface area. This dimensional change enables rapid moisture removal at low temperatures
3Speed
If conventional spray drying is used, then processing speed is maintained, but product quality deteriorates due to load loss
Solution Approach 1:
The invention changes multiple parameters simultaneously: temperature (from 180-200°C to below 100°C), droplet size (through intensive atomization), and residence time (extended in large chamber). These parameter changes maintain processing throughput while preserving active ingredients, achieving both speed and quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach preserves the active ingredients by minimizing heat-induced degradation, maintaining the weight percentage of molecular types within 5% of the initial values and ensuring stability during elevated temperatures for up to 1000 hours, resulting in a high-quality dried powder with improved shelf-life and performance.
Implementation Method 1
suspending the electrostatically charged, wet particles for a sufficient time to permit repulsive forces induced by the electrostatic charge on at least some wet particles to cause at least some of such particles to divide into wet sub-particles
Implementation Method 2
continuing the suspending step, without the presence of any heated drying fluids, for a sufficient time to drive off a sufficient amount of the liquid solvent within most of the wet particles to leave a plurality of dried particles
Data Source
AI summary
Methods and apparatus provide for spray drying a liquid product into a dried powder without applying heat, including: forming a slurry including a liquid solvent, a carrier, and an active ingredient; applying an electrostatic charge to the slurry; atomizing the charged slurry to produce a plurality of electrostatically charged, wet particles; suspending the electrostatically charged, wet particles for a sufficient time to permit repulsive forces induced by the electrostatic charge on at least some wet particles to cause at least some of such particles to divide into wet sub-particles; and continuing the suspending step, without the presence of any heated drying fluids, for a sufficient time to drive off a sufficient amount of the liquid solvent within most of the wet particles to leave a plurality of dried particles (the powder), each dried particle containing the active ingredient encapsulated within the carrier.