Valves nitrogen

Another engineer arrived after another five or ten minutes. He fetched the process supervisor and then entered the vessel. He also collapsed. The supervisor ealled the plant fire service. Before they arrived the third man recovered sufficiently to be able to climb out of the vessel. The second man was rescued and recovered, but the first man died. It is believed that an hour or two before the incident, somebody opened the nitrogen valve leading to the vessel and then closed it. 

A reactor was cooled by a molten salt. At startup the salt was heated to reaction temperature by an electric heater. During one startup the temperature of the salt rose at only half the usual rate. Obviously one of the heaters was faulty, but no fault could be found. The problem was finally traced to a nitrogen valve, which had been left open. The flow of nitrogen through the reactor was taking away half the heat. 

I im on the liquid nitrogen valve to cool the trap, if it is not a part of the time program. 

The plant operator opened the nitrogen valves that were both upstream and downstream of the plants nitrogen pressure regulator to pad the truck. The truck manifold that was in front the right rear wheels contained a pressure gauge that read the expected 20 psig (1.36 bar). The operator opened the proper liquid delivery valves, started the unloading pump, and left to handle other chores. The driver stayed with the truck, as was the normal procedure. 

Engineers determined that a nitrogen valve was opened to the hose connected to the tank trailer manifold. The nitrogen gas never entered because there was a closed valve atop the tank. It seems the truck driver misunderstood the recent nitrogen supply piping modification the open and closed positions on this oval handle ball valve. 

After an initial warmup period, the main nitrogen valve is opened and the flowrate regulated to 21 liters per minute in order to obtain a velocity (V) of 50 centimeters per second past the drop. The humidity of the stream is then set in order to obtain the desired supersaturation ratio. The supersaturation ratio (SSR) is defined as the partial pressure of the water in the gas stream divided by the partial pressure of the water at the initial temperature of the droplet (5.5 C). The supersaturation ratios used were 1.0, 1.5,... 

Fig. 5.1 Sampling with vacuum in a closed system, a Immersion tube, b Product valve, c Sample valve, d Nitrogen valve, e Vacuum valve, f Gauge vessel...

Syringe pump on/off 2, nitrogen valve on/off 3, start of SVE controller. Abbreviations i-PrOH, isopropanol MeOAc, methyl acetate (desorption solvent). 

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