Pumps and Gas-Moving Equipment

Power and work required. Using the total mechanical-energy-balance equation (2.7-28) on a pump and piping system, the actual or theoretical mechanical energy Ws J/kg added to the fluid by the pump can be calculated. Example 2.7-5 shows such a case. If r is the fractional efficiency and the shaft work delivered to the pump, Eq. (2.7-30) gives 

The mechanical energy Wg in J/kg added to the fluid is often expressed as the developed head H of the pump in m of fluid being pumped, where 

To calculate the power of a fan where the pressure difference is of the order of a few hundred mm of water, a linear average density of the gas between the inlet and outlet of the fan is used to calculate and brake kW or horsepower. 

Since most pumps are driven by electric motors, the efficiency of the electric motor must be taken into account to determine the total electric power input to the motor. Typical efficiencies of electric motors are as follows 75% for-j-kW motors, 80% for 

Suction lift. The power calculated by Eq. (2.7-3) depends on the differences in pressures and not on the actual pressures being above or below atmospheric pressure. However, the lower limit of the absolute pressure in the suction (inlet) line to the pump is fixed by the vapor pressure of the liquid at the temperature of the liquid in the suction line. If the pressure on the liquid in the suction line drops to the vapor pressure, some of the liquid flashes into vapor (cavitation). Then no liquid can be drawn into the pump. 

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Gas-moving Equipment. The principal types of equipment available for gas pumping are blowers, compressors, ejectors, fans, and vacuum pumps. The following is a general guide for selection of equipment based on pressure and capacity requirement ... 

Petrochemical Plant classes of equipment monomer plant gas compressors, screw conveyors, pumps, and other non-moving equipment ... 

The primary key for safe laboratory operations is the fume hood, which removes harmful vapors. The fume hood should be correctly drawing air across the open surface. Clutter within the hood must be minimized for safe operations. Outside the hood, all equipment such as gas cylinders, must be safely secured. Personnel must be protected from any moving equipment, such as belts and wheels of pumps and air compressors. All emergency equipment, such as fire extinguishers and spill containment pillows, must be readily accessible. 

As with chemical weapons ingredients, the chemical equipment needed to make chemical warfare agents is commercially available just about anywhere. Certainly, to set up a full-scale poison gas production line, terrorists would need reactors and agitators, chemical storage tanks, containers, receivers, condensers for temperature control, distillation columns to separate chemical compounds, valves and pumps to move chemicals between reactors and other containers. Additionally, ideally the equipment would be corrosion-resistant. For a full-scale mustard gas production plant the price tag would be between 2.5 and 5 million. Approximately 10 million would be required to set up a plant to manufacture tabun, sarin or soman.47 Terrorists, however, can be assumed to forego the scale and the safety precautions that most governments would consider essential for a weapons programme. In fact, standard process equipment or a laboratory set-up of beakers and... 

Both the vacuum section and moving parts of vacuum pumps may be lubricated by the same lubricants as those used for gas compressors. This only applies to industrial equipment producing low or medium vacuum. For high vacuum, lubricants must have better properties, particularly vapour pressure and sealing of the vacuum section, therefore more viscous lubricants are used. The best petroleum-based vacuum pump lubricants are narrow oil fractions of sufficiently high viscosity. These oils have high flash points and do not contain low-boiling components which will affect the flnal vacuum achieved, produce oil mist and lead to condensate formation in adjacent areas. 

Fully automated reactor start-up can be achieved by the LRM, yet another passive device incorporated in the RAPID concept. Figure XVII-5 shows the LRM basic concept. LRM is similar to LIM however, Li is reserved in the active core part prior to reactor start-up. The LRM is placed in the active core region where the local coolant void worth is positive, as is also the case with LEMs and LIMs. The RAPID is equipped with an LRM bundle in which 9 LRMs and an additional B4C rod are assembled. The reactivity worth of the LRM bundle is +3.45, once each LRM includes a 95% enriched Li enclosed in a 20mm-diameter envelope. A B4C rod is used to ensure the shutdown margin (-0.5 ). An automated reactor start-up can be achieved by gradually increasing the primary coolant temperature with the primary pump circulation. The freeze seals of LRMs melt at the hot standby temperature (380°C), and Li is released from the lower level (active core level) to the upper level to achieve positive reactivity addition. An almost constant reactivity insertion rate is ensured by the LRMs because the liquid poison, driven by the gas pressure in the bottom chamber, flows through a very small orifice. It would take almost 14 hours for the liquid poison to move into the top chamber completely. A Sn-Bi-Pb alloy is used as the freeze seal material to ensure the reactor start-up at 380°C. 

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