Drying and gas or vapor contact with solids – Process – With fluid current conveying or suspension of treated material
Patent
1996-10-30
1999-05-04
Bennett, Henry
Drying and gas or vapor contact with solids
Process
With fluid current conveying or suspension of treated material
34378, 34407, 34408, 34171, 34172, F26B 308
Patent
active
058990038
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns a method and apparatus for drying of solid materials, such as granular products alone, or in combination with fluids.
DESCRIPTION OF RELATED ART
Drying of certain granules, such as in the food industry and feed industry, places great demands on the drying process in order to obtain the best attainable product quality with as little product deterioration as possible while at the same time maintaining the product's physical, chemical, visual and nutritional properties.
Known methods are substantially based on drying with warm air, in which the drying air, after use, is vented to the atmosphere with consequential energy loss. An improvement of this simple drying principle resulted in closed drying plants in which charges of mass to be dryed are located in a drying room connected with a closed loop for circulating drying air, optionally in combination with a heat pump.
U.S. Pat. No. 4,335,150 describes a drying process, in which humid material is passed over an absorption material.
None of these prior art principles have provided satisfactorily results, either because of reduced quality of excessive process costs.
NO Patent No. 164,331 describes a method and an apparatus for drying an/or freezing of granules in which the granules are located in a zone which is swept with a gaseous drying medium and, optionally, a refrigerant, thus keeping the granule mass in motion. The drying medium moves in a closed circuit provided with a heat pump.
The drawback of the latter method is that the drying in the drying chamber 10A occurs adiabatically. As a result the gaseous drying medium, during its passage through the drying mass, is cooled because of the evaporating humidity. The ability of the drying medium to accommodate humidity thus decreases continuously during the flow through the mass. In spite of the presence of a heat pump and circulation of drying medium, this principle involves for example unnecessary high operating costs and cap costs, since it requires circulation of relatively large volumes of drying medium in order to maintain acceptable drying capacity.
SUMMARY OF THE INVENTION
The main object of the invention is to provide a method and apparatus that reduces the investment costs as well as operating costs.
According to the present invention, the drying zone, comprising the mass to be dried (hereinafter referred to as "drying mass") and a flowing drying medium, such as air, is supplied with heat to compensate for heat loss resulting from the volatile compound evaporating from the mass. In this way the drying zone is operated according to a substantially isothermal principle thereby increasing the absolute absorption capacity of the drying medium compared with an adiabatic drying process, dependent on the heat supplied.
The term "drying mass" is meant to comprise any material, solid as well as fluid, which can be subjected to drying to remove volatile components. Examples of drying masses in this connection can comprise particles, powder, granules, suspensions, emulsions and solutions. An example of handling of fluids (suspensions and solutions) may constitute distribution of the drying mass on the surface of stationary inert bodies, such as plastic spheres whereby the drying mass establishes a film on the inert body, thus allowing for vaporization of volatile components from a larger area. The inert bodies are stationary in the sense of remaining within the drying chamber during the drying process.
At 80.degree. C., the ability of air to absorb humidity increase about 32 times in an isothermal process compared with an adiabatic process. The drying mass can be present as a fixed bed or as a fluidized bed. The process can be accomplished in batches or performed continuously. In a preferred embodiment, the drying mass moves continuously counter-currently to the drying medium, thus establishing a true continuous process.
The heat can be supplied in the vicinity of the drying mass, or can be supplied between two or more drying stages. The heat supply in co
REFERENCES:
patent: 4602438 (1986-07-01), Draper et al.
Jonassen Ola
Kramer Kjartan
Strommen Ingvald
Bennett Henry
Sinvent AS
Wilson Pamela A.
LandOfFree
Method and apparatus for drying of materials containing volatile does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for drying of materials containing volatile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for drying of materials containing volatile will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1860991