The July 2015 CropLife Retail Facilities Report features an article on the new product of heated, insulated aboveground storage tanks offered by the Heartland Tank Companies. The article explains how these storage tanks, new to the liquid fertilizer industry, combat the negative effects of cold temperatures on some liquid fertilizers.
The Cold, Salty Problem
Wholesalers and retailers experience issues with storing certain liquid fertilizers and starter fluids during the winter due to cold temperature effects. When an aboveground storage tank of 32% liquid nitrogen has an average internal temperature below thirty degrees, the product begins to salt out. The same situation occurs for ammonium thiosulfate when it reaches a certain minimum temperature.
While this salting out issue can be avoided by having liquid fertilizer deliveries made during the warmer spring temperatures, the 2014 railroad transportation issues negated that option. Blamed on bad winter weather and significant increase in North Dakota oil, the railroad system could not keep up with the demand of many industries, including owners of liquid fertilizer tanks. Delays led to close calls or lack of product for liquid fertilizer wholesalers and retailers during the spring 2014 planting season.
Despite the rail industry pumping billions of dollars into its infrastructure to alleviate this problem, many liquid fertilizer wholesalers and retailers started looking for other options.
Heated, Insulated Storage Tank Solution
One possible solution for wholesalers and retailers would be to have the product delivered in the fall and store it through the winter. In more northern states, winter storage is a guarantee for product salt. After discussing the issue with a few clients, Heartland Tank Companies offered a solution of using a heated, insulated tank to maintain product temperature through winter temperature lows.
The Arthur Companies in Harvey, North Dakota tested and proved out the heat system for a steel storage tank with an internal PVC liner. The Harvey tank uses a heat system that introduces heat externally to the tank. Introduction of heat is only needed occasionally because the tank is encased in panels of insulation to minimize heat escape. The system is automated, so that the heat system will only be turned on when the average temperature of the product reaches a minimum temperature.
A system for a double wall storage tank has also been implemented in Madison, South Dakota where internal liners cannot be used. Because the tank only contains steel parts, a glycol heat coil system is placed inside the tank and connected to an automated system to track and control the average product temperature.
The Harvey system demonstrated its ability to maintain product temperature as 46 degrees despite the outside temperature dipping down to -20 degrees. Such success demonstrates this valid solution of using a heated, insulated liquid fertilizer storage tank to store product through the winter.