Fires centrifuges

Production and Shipment. Estimated adiponitrile production capacities in the U.S. in 1992 were about 625 thousand metric tons and worldwide capacity was in excess of lO metric tons. The DOT/IMO classification for adiponitrile is class 6.1 hazard, UN No. 2205. It requires a POISON label on all containers and is in packing group III. Approved materials of constmction for shipping, storage, and associated transportation equipment are carbon steel and type 316 stainless steel. Either centrifugal or positive displacement pumps may be used. Carbon dioxide or chemical-foam fire extinguishers should be used. There are no specifications for commercial adiponitrile. The typical composition is 99.5 wt % adiponitrile. Impurities that may be present depend on the method of manufacture, and thus, vary depending on the source. 

Motor-driven, multistage reciprocating compressors have reportedly been the most popular choice for aeroderivatives. Motor-driven, oil-fiooded screw compressors are also used in some cases. High horsepower, multistage centrifugal compressors, similar to those used at many pipeline compressor stations, may be required for the newer heavy-duty units if the distribution pipeline pressure is insufficient (see Pipelines). Gas turbines have more stringent fuel-gas specifications in terms of cleanliness than do gas-fired boilers. Thus oil- and water-knockout systems, coalescing filters, and fine-mesh filters are used. 

National Fire Protection Agency (NFPA) NFPA-20 Centrifugal Fire Pumps... 

Leaks of process materials are the process industries biggest hazard. Most of the materials handled will not burn or explode unless mixed with air in certain proportions. To prevent fires and explosions, we must therefore keep the fuel in the plant and the air out of the plant. The latter is relatively easy because most plants operate at pressure. Nitrogen is widely used to keep air out of low-pressure equipment, such as storage tanks (Section 5.4), stacks (Section 6.1). centrifuges (Section 10.1), and equipment that is dcpressured for maintenance (Section 1.3). 

One centrifuge was powered by a hydraulic oil installation 2-3 m away. A leak of oil from a cooler was ignited, and the fire was spread by oil and product spillages and by plastic-covered cables. It destroyed the plastic seal between the centrifuge and its exit chute. There was an explosion in the chute and a flash fire in the drier to which it led. The centrifuge exit valve was closed, but the aluminum valve actuator was destroyed. Fortunately, the exit valve did not leak, or several tons of solvent would have been added to the fire. Aluminum is not a suitable material of construction for equipment that may be exposed to fire. 

Linty particles and sticky buffing compounds can cause trouble in high efficiency centrifugals and fabric arresters. Fire hazard is also often present. 

Figure 12-42. Results of internal chlorine gas fire and extensive corrosion in centrifugal compressor. Middle section of shaft with extensive damage to loss of center compression wheels. Note that ferric chloride is present.

External fires, 450 Unwetted gas only vessels, fire, 454 Viscosity correction, centrifugal pumps, 203-207... 

Another alternative is to conduct a scale model experiment in a centrifuge in which g is now increased [13]. Modifying both p and g in the model can allow the preservation of more groups. Thus, scaling in fire is not complete, but it is still a powerful tool, and there are many ways to explore it. Illustrations will be given later of successful examples in scale modeling and correlations to specific fire phenomena. 

For onshore facilities, water may be supplied from local public water mains, storage tanks, lakes and rivers. In these cases a conventional horizontal pump is used. The preferred design for onshore fire water pumps is a horizontal centrifugal type with a relatively flat performance curve (i.e., pressure versus quantity). The discharge pressure is determined by the minimum residual pressure required at the most remote location of the facility flowing its highest practical demand with allowances added for piping friction losses. 

NFPA20 Standard on the Installation of Centrifugal Fire Pumps. 

National Fire Protection Association (NFPA), NFPA 20. Installation of Centrifugal Fire Pumps. NFPA, Quincy, MA, 1990. 

Horizontal centrifugal pumps should provide 150% of the rated capacity at 65% of the rated pressure, with a shutoff head of not more than 120% of the rated pressure. This pump should be used only when suction supply is under a positive head. Suction pipes should be designed to preclude the formation of air bubbles. A characteristic curve for a rated fire water pump is shown in Figure 7-15. 

NFPA 20—Standard for the Installation of Centrifugal Fire Pumps NFPA 24—Standard for the Installation of Private Fire Service Mains and Their Appurtenances... 

The catalyst preparation area is protected by an automatic water-spray sprinkler system that is actuated by associated heat detectors. Fixed fire water monitors surround this process area. The water for these fire protection systems is supplied through 8-inch underground water mains by three (two diesel and one electric) horizontal, centrifugal, 2500... 

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