Eliminating Hydrogen Fire in CCR Units

In the propane dehydrogenation facility, the CCR unit is supplied by UOP. This unit is able to continuously regenerate catalysts based on a dedicated PLC control logic. The system operates automatic process valves to regulate and control the flow of the catalyst through the system, isolating and altering process atmospheres..

The Oleflex catalyst regeneration system requires catalyst transfer from hydrogen/ hydrocarbon atmosphere in reactors to the oxygen rich atmosphere in the regenerator and back again. This requires the valves to be operated at a high cycle normally about 8 times an hour.

Due to this high operation cycle, the gland packing tends to become loose leading to minor passing. And due to presence of hydrogen, there are chances of fires.

It was identified that high rate of packing leaks was observed in the Fisher V-Ball and Metso ball valve. These are rotary valves while compared to other linear valves. Both the valves have conventional packing design with nut and bolt gland tensioning using gland followers and lock nut. This is the conventional style used in general purpose valve design.

It was observed that the valve started to leak from the gland even after one month of torque.

Also, the packing material used is laminate graphite. Better sealing will be provided by PTFE. The

limitation is temperature should be less than 230 Deg Operations have confirmed that the operating.

temperature is well below 200 Deg C. Therefore, a reliable alternative would be to replace the valve with an enviro seal package with PTFE material.