Draining an Ammonia tank in total security

Case study

  •  The context :

Guichon was approached to develop a custom valve for which the requirement was not linked to the material, nor to operating conditions but to the installation at the customer’s facility. The tank bottom valve is integrated into the ammonia fabrication process at a production facility in Eastern Europe, to allow the discharge of the ammonia tank.

Being a highly polluting chemical for the environment, leaks are not tolerated. The tank containing the ammonia is itself contained within a second tank with an isolation space of 1.3 m between the two walls.

The valve must be capable of draining the inside tank (INNER TANK) across the safety tank (OUTER TANK).

discharge tank bottom valve ammonia


  • The constraints :

– No possibility of vertical drainage: requirement of horizontal drainage for an ammonia tank, protected by a secondary tank, using a pneumatically actuated globe valve
– A space of 1232 mm between the two tanks!
– Challenging climate conditions ranging between -35°C to + 55°C, that cause the expansion of the external metals of the installation
– The need for an automatic closing system on the valve in the event air is lost

  • The solution developed by Guichon :

A DN12x 10, PN50 globe valve traversing the two tanks with the following characteristics:
guichon discharge valve ammonia tank
– A horizontal valve (having sufficient pressure of 70 bar) with an overall length greater than 3.70 m !
– A three piece stem of three meters, guided by a system of sleeves
– A double acting pneumatic actuator
– Outlet at 90°tank bottom valve detail process ammonia guichon
– Safety spring to ensure closing at the extremity of the valve in the ammonia tank upon loss of air
– An expansion bellows that relieves the expansion of materials on the external part of the valve (due to significant temperature differences, -35°C to + 55°C).
– A body in painted carbon steel and trim in 316L

Guichon advantages

1 – a design that perfectly respects the installation constraints of the customer
2 – a spring return system with dual functions of safety and perfect seat tightness
3 – mastery welding bellows
* internal, creating a double seal between the fluid to the outside of the valve
* external, to ensure tightness in the event of expansion
4 – reativity to find solutions at various stages of the production due to challenges created by the size of the valve