Tank management removal

Managing a salt-water aquarium. A tank at the New Jersey State Aquarium has a volume of 2.9 million liters.7 Bacteria are used to remove nitrate that would otherwise build up to toxic levels. Aquarium water is first pumped into a 2 700-L deaeration tank containing bacteria that consume 02 in the presence of added methanol ... 

The correct management of the various gaseous, liquid and solid wastes determines the regularity of production. The gaseous wastes flow through exhaust systems equipped with absolute filters and soda lime and activated charcoal traps. They are discharged into the atmosphere after analysis of their krypton 85 and iodine content. The liquid wastes from the various cells are stored in 1 nr tanks (located in Petrus) and removed periodically by a shielded tank truck for transport to a liquid waste treatment station in another C.E.A. center. 

During the investigation, it was discovered that a maintenance worker had found water in tank 701. He was told to check the Unit 7 tanks to ensure they were ready for the T34 production startup. Unit 7 had been shut down previously (see Physical Plant Context ). The startup was scheduled for 10 days after the decision to produce additional K34 was made. The worker found a small amount of water in tank 701, reported it to the maintenance manager, and was told to make sure the tank was bone dry. However, water was found in the sample taken from tank 701 right before the uncontrolled reaction. It is unknown (and probably unknowable) whether the worker did not get all the water out or more water entered later through the same path it entered previously or via a different path. We do know he was fatigued and working a fourteen-hour day, and he may not have had time to do the job properly. He also believed that the tank s residual water was from condensation, not rain. No independent check was made to determine whether all the water was removed. 

Continuous-flow stirred-tank reactors (CSTRs) can be cooled in three ways. The most elegant method is to allow boiling of the monomer or solvent so that the heat of reaction is removed in an overhead condenser. The pressure in the vessel is set to give the desired temperature. The condensate can be returned to the vessel or recycled back to the feed. This process is commonly used for polystyrene. Chilling the feed is another means for managing the exotherm in a CSTR. Refrigeration to -40°C has been used for the bulk, continuous polymerization of PMMA. Laboratory reactors and small-scale industrial reactors can be cooled using jackets or internal coils, but this method scales up poorly. 

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