Method for producing tri-calcium phosphate
A method for producing tri-calcium phosphate admixes water, hydrated lime, and phosphoric acid in a reaction vessel to form a tri-calcium phosphate slurry. The slurry is then placed in physical contact with heated air through a spray head to evaporate water from the slurry. The preferred embodiment of the method utilizes an agitated air dryer.
This patent application claims priority from a provisional application having Ser. No. 60/505,397 and filed on Sep. 25, 2003. And, this patent application claims priority from a provisional application having Ser. No. 60/505,397 and filed on Dec. 4, 2003.
BACKGROUND OF THE INVENTIONThis invention generally relates to tri-calcium phosphate production. More specifically, the present invention utilizes a production method with a spray head in combination with an agitated air dryer system.
Tri-calcium phosphate is the generic name for precipitated calcium hydroxyapatite. High-quality food-grade tri-calcium phosphate (“TCP”) is used as a calcium supplement in products such as cereals, bakery mixes, dry gravy mixes, spice blends, flours, beverages, animal foods and pharmaceuticals. TCP is also used as an anti-caking agent in salt substitutes, dry beverage mixes, dry soup mixes, dry gravy mixes, spice blends and other hydroscopic food products that require flow conditioning. TCP also serves as a dispersant, a suspension agent for polymerization of styrene, and a ceramic coloring agent.
Currently, TCP slurries are produced by admixing water, hydrated calcium or lime (CaOH), and phosphoric acid in a stainless steel reaction vessel 7 if
The industry standard for removing the moisture is drying the slurry using a combination of steam heated double drum dryers, gas fired flash dryers 12, and air conveyance in
Therefore, an efficient TCP production method is needed that utilizes less water and energy for drying TCP to meet commercial needs.
SUMMARY OF THE INVENTIONThe present invention is a method for producing tri-calcium phosphate. The method admixes water, hydrated lime, ascetic acid, and phosphoric acid in a reaction vessel to form a tri-calcium phosphate slurry, and then places the slurry in physical contact with air at a temperature sufficient to evaporate the water in the slurry.
The TCP slurry mixes with previously dried TCP (0%-2% moisture) to obtain a blended TCP product that has approximately 30% moisture content. This blend then feeds into an agitated air dryer (AGA) as manufactured by International Technology Systems, Inc. of Wisconsin.
The moisture in the blended TCP evaporates in the AGA dryer by a turbulent stream of heated air. The present invention resulted from different locations of slurry sprays relative to the dryer and various types and amounts of insulation placed upon the burner housing and the dryer itself. The air temperature at the inlet 5a of the dryer 5 will vary between 550° F. and 650° F. The air temperature at the outlet 5b of the dryer 5 will vary between 190° F. and 210° F. The hot moist air and dried product exit the dryer into a bag house B as in
The hot moist air exits through the top of the bag house after passing through fabric bags. The fabric bags operate similar to the bags in a vacuum cleaner. The fabric bags allow the hot air to pass through, but not the fine, airborne TCP particles. This system keeps all the TCP contained and eliminates waste.
The AGA drying system uses approximately 1,500 BTU to produce one pound of TCP product with 2% moisture. This system requires about 40% of the energy used by the double drum drying system 10. The present invention produces approximately 1,650 lb/hr of finished TCP. Furthermore, the temperature, turbulence and velocity of the air stream in the AGA drying system can be readily adjusted to produce various granulations and densities of the TCP to meet the specific requirements of a variety of products.
Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of the presently preferred, but nonetheless illustrative, embodiment of the present invention when taken in conjunction with the accompanying drawings. Before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
One object of the present invention is to provide a new and improved method for producing tri-calcium phosphate.
Another object of the present invention is to combine the advantages of a spray dryer and an agitated air dryer.
Another object is to provide a method for producing tri-calcium phosphate that reduces waste of TCP by containing particulate TCP within the equipment.
Another object is to provide a method for producing tri-calcium phosphate that uses 40% of the energy of prior art methods to operate.
A still further object is to provide a method for producing tri-calcium phosphate that readily provides TCP of various granulations and densities.
These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention.
Variations and modifications to the subject matter of this invention may occur to those skilled in the art upon review of the development as described herein. Such variations, if within the spirit of this development, are intended to be encompassed within the scope of the invention as described.
BRIEF DESCRIPTION OF THE DRAWINGS
The same reference numerals refer to the same parts throughout the various figures.
DETAILED DESCRIPTION A new and useful method for producing commercial tri-calcium phosphate, or TCP, utilizes less water and energy than current methods. TCP has a molecular weight of 502 and has the following chemical formula: Ca5(PO4)3(OH). The processes of the present invention produce a TCP product with less energy and less waste than the current methods. According to the method of the present invention in
In the preferred method of the invention, an agitated air or AGA system 5 dries the TCP slurry 6. Suitable AGA systems 5 may be obtained from International Technologies Systems, Inc. The agitated air system 5 utilizes a dispersion drum and paddles to separate the TCP slurry 6 into small particles so that a fast moving stream of hot air may remove the moisture in the slurry 6 through evaporation. In the preferred method of the invention, TCP slurry 6 is fed through a spray head 5c directly upon the dispersion drum of the dryer 5. In an alternate method, the dispersion drum has paddles. In addition, the AGA system 5 has a production capacity of about 1,300 lb to about 2,000 lb per hour, versus about 800 lb to about 900 lb per hour with the prior art dryers. Further, the AGA system 5 works more efficiently at lower moisture levels than current methods. A double drum drying system 10 of the prior art, as in
Turning to
The TCP produced using the method of the present invention may be used in various products, including but not limited to, foods, ceramics, bone meal, and beverages. The TCP products may also be used in polystyrene manufacturing. From the aforementioned description, a method for producing tri-calcium phosphate has been described. The production method is uniquely capable of drying a TCP slurry.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Therefore, the claims include such equivalent constructions insofar as they do not depart from the spirit and the scope of the present invention.
It is to be understood that while certain embodiments of the invention are described and illustrated herein, the invention is not to be limited to the specific form or arrangement described and shown herein. It will be apparent to those skilled in the art that various changes may be made without departing from the scope and spirit of the invention, and the invention is not to be considered limited to what is shown and described herein.
Claims
1. A method of producing tri-calcium phosphate in marketable form from water, hydrated lime, phosphoric acid, and related ingredients comprising:
- forming a slurry of approximately 72% water by weight and 28% tri-calcium phosphate by weight;
- placing said slurry in contact with heated air produced by an agitated air system producing at least 1,300 pounds per hour of tri-calcium phosphate;
- using negative air pressure within said agitated air system to move said slurry; and,
- thereby producing tri-calcium phosphate in a dry form with no more than two per cent moisture content.
2. The production method of claim 1 further comprising:
- said agitated air system having an agitated air dryer with an inlet and an outlet and including a spray head located between said inlet and said outlet;
- whereby said spray head directly applies said TCP slurry onto said dryer.
3. The production method of claim 2 further comprising:
- said inlet having an air temperature of approximately 500° F. to approximately 700° F.; and,
- said outlet having an air temperature of approximately 190° F. to approximately 210° F.
4. A method of producing tri-calcium phosphate using water, hydrated lime, phosphoric acid, and related ingredients wherein the improvement comprises:
- forming a slurry from the admixture of the water, hydrated lime, phosphoric acid and related ingredients within a vessel;
- using an agitated air dryer to create a stream of heated air; and,
- directing said slurry through a spray head in contact with a stream of heated air to evaporate water from said slurry;
- whereby said method produces tri-calcium phosphate having a moisture content less than approximately ten per cent.
5. The production method of claim 4 further comprising:
- splitting said tri-calcium phosphate produced by said method;
- returning a portion of said tri-calcium phosphate into said slurry; and,
- packaging the other portion of said tri-calcium phosphate for delivery.
6. The production method of claim 5 wherein said vessel is a dispersion drum.
7. The production method of claim 6 further comprising:
- said dispersion drum having a paddle.
8. A method of producing tri-calcium phosphate in marketable form from water, hydrated lime, phosphoric acid, and related ingredients comprising:
- forming a slurry of approximately 72% water by weight and 28% tri-calcium phosphate by weight;
- placing said slurry in contact with heated air produced by an agitated air system having an agitated air dryer with an inlet, an outlet, and a spray head located between said inlet and said outlet; and,
- moving said slurry through said agitated air system using negative air pressure;
- thereby producing tri-calcium phosphate in a dry form with no more than two per cent moisture content at a rate of at least 1,300 pounds per hour.
9. The production method of claim 8 further comprising:
- said spray head directly applies said TCP slurry onto said dryer.
Type: Application
Filed: Sep 25, 2004
Publication Date: Jun 9, 2005
Inventor: William Kuzma (Sesser, IL)
Application Number: 10/950,043