When Southern Gardens Processing Corp. recently built a citrus processing plant in Clewiston, FL, it was Florida's first new orange juice processing plant in nearly two decades. A key issue for the plant's design was its insulation, needed to protect refrigerated fluid streams. The insulation has to stand up to highly humid weather conditions, as well as the corrosive effects of citrus oils. To address these problems, the plant designers specified Foamglas insulation, from Pittsburgh Corning Corp.
Southern Gardens is a United States Sugar Corp. company. U.S. Sugar is one of the nation's leading agricultural companies and is among the largest producers of raw sugar and is a major grower and marketer of citrus. The first phase of construction on the facility began in 1992, and its grand opening was in early 1994. Total cost for the first phase of construction, including the infrastructure for future expansions, was approximately $40 million.
In its first phase, the plant was designed to process 45,000 boxes of oranges per day, or approximately 86 trailer loads of oranges. This production yields about 41,000 gal of concentrated orange juice, or almost 300,000 gal of single-strength (not-from-concentrate) juice. These juice products are sold to be packaged for retail sale under familiar brand, private label and food service names. Additionally, the plant produces products that are used in the food, fragrance, electronics and agricultural industries.
From Orange to Juice--The Process
The juice is then directed to one of two possible paths. If it is to be sold as single-strength, it passes through a pasteurization process and is quickly chilled. Juice to be sold as concentrate moves through evaporator units where water is removed. The concentrate, having by this time been reduced to 1/6 of its former volume, is then chilled. The plant, which runs on a 22-hour production day, can funnel both concentrate and single-strength juice simultaneously. After blending and cooling, the concentrated juice is transported through pipes to an enclosed tank farm. In the tank farm, three million gal of concentrate are stored in 16 tanks (187,000 gal each) and stored at a constant temperature of 18°F.
Foamglas Insulation Meets Unique Juice Processing Needs
According to Roland Young, P.E., who was Director of Mechanical Engineering for HWH Architects-Engineers-Planners, Inc. in Orlando, Fla., the piping insulation selected was critical to the long-term success of the system. HWH is the firm that was commissioned to design the entire plant, including all mechanical piping systems during the first phase of construction.
|Fig. 2. Each tank is supported by concrete and two three-inch layers of FOAMGLAS insulation.|
According to Stuart Salter, who was Vice President and General Manager of Southern Gardens when the installation took place, Foamglas insulation was chosen because it best met the plant's needs for strength and resistance to citrus acids. "We specified Foamglas insulation because it is impervious to citrus oil and has a tremendous capacity to support weight," he says. "This is critical due to the destructive nature of citrus oil, which can destroy unprotected polystyrene."
Polystyrene and polyurethane insulation may compact or deform as much as 10 percent before developing full, published compressive strength, which may cause cracking of the concrete-slab floor. Citrus acid spills then may enter any cracks in the concrete floor and dissolve the polystyrene, creating even more damage. As with piping applications, insulation and system failure can be quite expensive to repair and can interrupt the manufacturing process.
"I've seen first-hand how citrus oil destroys unprotected plastic foams," says Salter. "It's just like pouring on lighter fluid-it just eats away at the material. Although polystyrene may be OK for wall applications, it just doesn't work if there is any likelihood that citrus oil will can get to the insulation. Even if everything is installed properly, cracks appear over time and the insulation will fail, causing a void between the concrete slabs and uneven settling of the tanks."
High compressive strength
Southern Gardens Citrus selected Foamglas insulation because of its unique blend of physical characteristics, which is important to the food and juice processing industry. Foamglas insulation combines excellent thermal performance, impermeability to liquid and vapor, noncombustibility and the highest compressive strength of any commonly used floor insulation.
"We specified Foamglas insulation because of its long-term performance," explained Salter. "It may cost more initially, but the value received more than justifies the extra cost because of its increased reliability and the fact that it is completely unaffected by citrus oil if it comes into contact. And in the real world, someday, at some point, it more than likely will."
Edited by Nick Basta