We currently have a 150' x 56' fixed roof tank with 2" of shell insulation (mineral wool) and two manway heaters. I have estimated that the existing heaters provide 5,000 ft² of surface. The tank will be entering a new service and we need to determine if additional heating is required. Our internal calculations have shown that in order to maintain 300°F, the required duty is around 3.5 million Btu/hour. The product enters the tank at around 310F. We approached two heater vendors for their analysis.
Our Calcs: 3,500,000 Btu/hr required
Vendor 1: 2,666,800 Btu/hr required (using only 1-1/2" insulation) and 4,774.5 ft² required.
Vendor 2: 3,567,000 Btu/hr and 2,028 ft² required.
Although both vendors have calculated widely different duties, I am concluding that the tank already has sufficient heating for the new service. Am I correct?
Our Calcs: 3,500,000 Btu/hr required
Vendor 1: 2,666,800 Btu/hr required (using only 1-1/2" insulation) and 4,774.5 ft² required.
Vendor 2: 3,567,000 Btu/hr and 2,028 ft² required.
Although both vendors have calculated widely different duties, I am concluding that the tank already has sufficient heating for the new service. Am I correct?
