Neutralization systems are crucial in chlorination plants. In case of an emergency leak of chlorine within the drum room and/or equipment room, chlorine neutralization system is a must for safety insurance.
SAC neutralization systems consists of a packed column mounted above a caustic soda holding tank forming one integral unit together with a re-circulating caustic soda pump, a ventilation fan and a Cl2 leak detector.
Under normal conditions, the neutralisation system will be in a standby mode. The system will hold caustic soda of 25% concentration (NaOH), with a suitable capacity enough to neutralise the leaked chlorine contained in the largest container in the drums room (i.e. if the drums are ton-containers, the system should be capable to neutralise one complete drum).
When the system is activated, the caustic soda is pumped from the holding tank and sprayed over the top of the packed column. As the extracted air, contaminated with chlorine gas, is blown up through the column the caustic soda reacts with the chlorine to produce sodium hypochlorite and sodium chloride solution. The pump shall continue to recycle the caustic soda until the leak condition has stopped.
Washing liquid (Caustic Soda) is sprayed and uniformly distributed by means of distributors or sprayers of solid cone, big passages, easily detachable for revision or change.
Drops retention, caused by the spraying system, is made within the packed column itself by means of a vertical flow demister, of high efficiency and low loss of head. This device avoids the dragging and projection of drops into the atmosphere as well as losses of neutralising solution. The demister shall be designed in a way that fluctuation of +15% of design flow can be allowed, without affecting the efficiency of retention.
Re-circulation of caustic soda shall be done -preferably- by means of a vertical seal less centrifugal pump, in order to avoid the problems of damage of seal and damages that can happen when the pumped liquid has solids or is prone to crystallisation. As an alternative, a horizontal pump with a double external flushed mechanical seal can be used.
Ventilation fan shall be sized to 10-room changes/hour.
A mixer can be incorporated in the system if required depending on the surrounding temperatures.
SAC is providing turnkey solutions including sizing, supply of the equipment and installation of the systems if required.