Fluidized Stucco Cooling and De-Steaming for Stable Gypsum Storage
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Solution Overview
Problem
The gypsum industry faces challenges in maintaining the quality of calcined gypsum stucco due to its physical and thermodynamic instability at high temperatures, leading to aging issues during storage, and the need for immediate cooling and de-steaming to meet temperature requirements for bagging, while existing coolers have high capital costs and require larger sizes.
Innovation Solution
A fluid bed stucco cooler apparatus that uses a water spray system and fluidization pad to cool and de-stress calcined stucco, with a rotating disk distributor to prevent clogging and a compact design for efficient cooling and de-steaming, allowing for standalone or series/parallel configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coil cooler is used to cool calcined stucco, then the stucco can be cooled and de-steamed, but the initial capital cost is high and the equipment size is large
Solution Approach 1:
The patent replaces the mechanical coil heat exchanger system with a fluidized bed cooling system that uses fluid dynamics and direct fluid contact for heat transfer. The fluidized bed apparatus uses a fluidization pad to suspend stucco particles and water spray nozzles to introduce cooling water directly into the fluidized stucco, eliminating the need for complex coil structures and heat transfer fluid systems while achieving effective cooling and de-steaming
Solution Approach 2:
The patent employs pneumatic fluidization using air to suspend and circulate stucco particles through the cooling chamber. The fluidization pad introduces air at the bottom to create a fluidized state, and water spray nozzles introduce cooling water as a fine spray that evaporates and cools the stucco particles. This pneumatic-hydraulic approach replaces the mechanical coil system with a more simple and cost-effective fluid-based cooling mechanism
2Reliability
If stucco is stored at high temperature, then storage is convenient, but the stucco ages and quality deteriorates over time
Solution Approach 1:
The patent applies preliminary cooling and de-steaming action before storage by cooling the stucco in a fluidized bed immediately after calcination. The system reduces the stucco temperature from calcination temperatures (around 250°F or higher) to below 250°F and removes excess moisture through the fluidized bed drying action. This preliminary treatment stabilizes the stucco before storage, preventing subsequent aging and quality deterioration during storage
Solution Approach 2:
The patent utilizes phase transition of water from liquid to vapor through evaporation in the fluidized bed. The water spray introduced into the fluidized stucco evaporates, absorbing heat and cooling the stucco particles. This phase transition mechanism provides efficient cooling and simultaneous moisture removal, achieving both temperature reduction and de-steaming in one process step
3Manufacturing precision
If tube mill grinding is used to process stucco, then the stucco is ground to required fineness, but mechanical energy adds heat preventing meeting temperature requirements for bagging
Solution Approach 1:
The patent merges the cooling function with the grinding process by positioning the fluidized bed cooler immediately after the tube mill grinder. The hot, ground stucco particles are directly fed into the fluidized bed where they are cooled by water spray evaporation and air fluidization. This integrated arrangement allows the stucco to be ground to required fineness and immediately cooled to bagging temperature requirements in a continuous process without intermediate storage of hot material
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
The fluid bed stucco cooler effectively reduces stucco temperature below calcination levels, enhancing age stability and reducing water and additive requirements, offering economic and performance advantages over prior art coolers.
Implementation Method 1
a water spray apparatus to spray water on the stucco
Implementation Method 2
The cooler includes a water spray apparatus or distributor to spray and distribute fluid, preferably water, in the plenum
Implementation Method 3
a fluidization pad and an agitator, to move and distribute the stucco within the plenum
Implementation Method 4
The cooler also includes a fluidization pad and an agitator, to move and distribute the stucco within the plenum
Implementation Method 5
refinements, such as the use of compressed air to prevent clogging of the water spray apparatus
Data Source
AI summary
The present invention is an apparatus and process for cooling and de-steaming hot calcined stucco used in the production of gypsum boards or bagged plaster. The apparatus is a fluid bed stucco cooler and comprises a cooler housing having a plenum having a stucco inlet and stucco outlet. The stucco cooler includes a rotating disk in the plenum. The rotating disk includes nozzle for spraying fluid, and is attached to a rotable shaft extending from the side of the cooler also includes a fluidization pad and agitator to help to mix the air and the stucco powder to insure fluidization, prevent channeling, and prevent the stucco powder from building up on the various components. The air also forces steam from the hot calcined stucco out through an air outlet located at the top of the stucco cooler, thereby de-steaming the stucco. The stucco flows through the plenum and passes over the cooling coils, thereby cooling the stucco as it reaches the stucco outlet.