Aqua Ammonia Storage Tanks
Carbon steel or stainless steel construction for the tank is recommended. If other materials are used, their compatibility with aqua ammonia should be verified by the tank manufacturer. Tanks should have a 30 psi pressure rating. They should be equipped with safety relief valves rated for that pressure and they should also be equipped with a vacuum breaker. Steel tanks should be grounded. Other tanks constructed of different material or with lower pressure ratings require careful design. Please contact us for further assistance.
Storage of Aqua Ammonia
Because the vapor pressure of aqua ammonia is about equal to the atmospheric pressure, it must be stored in closed containers.
The storage area should be dry and cool. If housed in a closed building, ventilation should be provided; either natural or mechanical. Avoid pocketing of ammonia vapor under floors, roofs or similar structures.
Remember, ammonia vapor will burn when mixed in air at concentrations between 15% to 28%. Sparks or ignition sources must be excluded wherever concentrations in this range could exist.
Materials for Piping & Fitting
Vapor lines should be sized at 1 or 1-1/4 inches and liquid lines at 2 inches. Schedule 40 or 80 steel pipe and malleable iron pipe fittings are acceptable. Do not use galvanized pipe or fittings and make sure the unions do not have brass seats. Make sure that other fittings such as valves, pressure reliefs and back checks are suitable for ammonia service. Plastic pipe and fittings (with manufacturer's approval) may also be used. Hose connectors need not be provided as Tanner Industries' transports carry adapters to fit standard pipe threads.
System Design
Unlike Anhydrous Ammonia, Ammonium Hydroxide storage systems do not have to comply with any published regulatory standards or specifications.
Therefore, it is imperative that these systems are designed by qualified personnel having prior experience with the product. Tanner Industries, Inc. can assist you in designing or modifying your system to operate in a safe, efficient and environmentally responsible manner.
Shipping Containers for Aqua Ammonia
Aqua ammonia is usually shipped in either cargo tanks, polyethylene drums or composite drums. Aqua ammonia drums should be stored out of the sun and away from heat. Drums should not be subjected to rough handling or to abnormal mechanical shock such as dropping or bumping. They should be opened carefully to permit the venting of any ammonia vapors which may have formed in the container. Use a wrench with a long handle, stand to one side and face away during the operation. Chemical safety goggles, face shield, rubber aprons and gloves should be worn. Allow accumulated pressure to vent before removing plug completely.
Drums should be emptied by gravity only. Use a faucet or safety siphon made of material resistant to ammonia; no brass or bronze. Application of pressure to the drum for unloading is dangerous and should not be attempted.
Ammonia solutions in water with concentrations between 10% and 35% have a DOT hazard classification of 8 and are to be labeled as Corrosive. Their identification number is UN2672 and are to be packaged in Group III containers. As of October 1, 1996 when HM-181 became effective, all Group III containers have to conform to UN specifications and standards. These requirements are outlined in CFR 173.24a(b)(4): Packaging tested as prescribed in CFR 178.605 of this subchapter may be used for liquids only when the vapor pressure of liquid conforms to one of the following:
(b)(4)(i) The vapor pressure must be such that the total pressure in packaging (i.e. the vapor pressure of liquid plus the partial pressure of air or other inert gases, less 15 psi at 131°F, determined on the basis of maximum degree of filling in accordance with paragraph (d) of this section) and a filling temperature of 59°F, will not exceed two-thirds of the marked test pressure, or
(b)(4)(ii) The vapor pressure must be such that the total pressure in packaging at 122°F must be less than four-sevenths of the sum of marked test pressure plus 15 psi, or
(b)(4)(iii) The vapor pressure must be such that the total pressure in packaging at 131°F must be less than two-thirds of the sum of marked test pressure plus 15 psi.
Bulk Deliveries by Cargo Truck
Deliveries to aqua ammonia storage tanks are made by bulk transport of approximately 6,400 gallons. A storage tank should be sized to hold at least one and one half times this amount or approximately 10,000 gallons.
Deliveries can be made using various methods, including pump, compressor, a combination of pump and compressor or gravity fill. Tanner Industries trailers are equipped with 2” hoses secured with locking cam locks for liquid transfer and ¾” or 1” hoses for vapor transfer.
Deliveries via our trailer mounted pump method can be used to transfer the liquid from the cargo tank into the customer’s tank. A vapor hose is connected between the two vessels to equalize pressures during delivery. Tractor air pressure is used at the end of the delivery to clear the residual liquid from the transfer hose. A vacuum breaker is also used between the customer’s tank and the trailer vapor connection to eliminate a possible vacuum condition.
Delivery via compressor method can be used to transfer the liquid and uses our tractor mounted compressor to produce a pressure differential of 10 to 15 psig of air or vapor pressure to push the material out of the cargo tank into the storage tank. At the end of the delivery the excess pressure in the trailer is used to clear the residual liquid from the hose.
The pump and compressor method utilizes both the on-board tractor mounted vapor compressor and the trailer mounted liquid pump. The compressor is used to convey vapor pressure from the customer’s tank into the trailer to create a pressure differential between the two vessels. The pump is utilized to transfer the liquid from the trailer into the customer’s tank. At the end of the delivery, the excess vapor pressure in the trailer is used to clear the transfer hose and piping into the customer’s storage tank. This method is typically used where long runs of piping are installed between the delivery point and the customer’s tank or when delivering into a large vertical storage tank.
The gravity feed method simply uses the force of gravity to move product from the delivery unit to the receiving tank. It usually only requires the use of one transfer hose for liquid aqua ammonia. There is no vapor connection. For this method of delivery, the storage tank must be at a lower level than the delivery unit and be equipped with a scrubber or vent system to allow for lower pressures to be maintained throughout the delivery process. At the end of the delivery the hose is emptied from gravity pressure.
In some cases, the customer provides their own stationary pump to complete the delivery. It should be kept in mind that the vapor pressure of the aqua ammonia is about equal to atmospheric pressure and that any suction pressure may cause the ammonia vapor to come out of solution and vapor lock could occur. Systems should be designed so that the pump is as near to the hose connection as possible and that the hose length required will be as short as possible, eighteen feet or less.
For additional Technical information contact us at 1-800-643-6226.
Notice: We believe the information contained here to be accurate and reliable; however, Tanner Industries, Inc. assumes no liability or responsibility in connection with the information or suggestions herein contained. Moreover, it should not be assumed that every acceptable test or safety procedure or method, precaution, equipment or device is contained within, or that abnormal or unusual circumstances may not warrant or suggest further requirements or additional procedures.
The information contained here should not be confused with federal, state, municipal, or insurance requirements, or with national safety or building codes, and no representations or warranties are made with respect thereto.