Blower capacity

Figure 4-60. Expander deliver capacity versus blower capacity requirements.

Evaluate the trade-off between the air blower capacity and wet gas compressor capacity. Spare horsepower at one can be used to unload the other. Consider ... 

A surface effect (air cushion) vehicle measures 10 ft by 20 ft and weighs 6000 lbf. The air is supplied by a blower mounted on top of the vehicle, which must supply sufficient power to lift the vehicle 1 in. off the ground. Calculate the required blower capacity in scfm (standard cubic feet per minute), and the horsepower of the motor required to drive the blower if it is 80% efficient. Neglect friction, and assume that the air is an ideal gas at 80°F with properties evaluated at an average pressure. 

The minimum positive pressure differential between the room and any adjacent area of less clean requirement should be 0.05 in. water (12 Pa), with all entryways closed. When the entryways are open, the blower capacity should be adequate to maintain an outward flow of air to minimize contamination migrating into the room. 

In the rotary blower, shown in Figure 5.2, gases are trapped in between two interlocking rotors which rotate in opposite directions. The blower requires no seal fluid. Because of the required clearances between the rotors of 0.025 to 0.25 mm (9.84x10 to 9.84x10 in), backflow reduces the blower capacity [3]. Also, overheating limits the pressure increase. 

As mentioned in the previous section, the RFCC operation can become delta-coke-limited by a constraint on the regenerator temperature or the air blower capacity. If the objectives of the operation are to increase resid intake or conversion, the options then will be ... 

Constant Riser Outlet Constant Coke Operation (Unit at Max Blower Capacity)... 

Fluidized-bed roasting accounts for most of the world zinc production today. Over the last 15 years, several zinc roasters have augmented their calcine production capacities with oxygen enrichment. These roasters typically encounter production increase limitations due to existing blower capacities, requirements for fluidization characteristics of the bed, and downstream gas-handling capacities. Oxygen enrichment provides roaster operators with a tool to increase roaster capacity in a cost-effective way. Several roaster plants utilize oxygen enrichment to improve calcine... 

Starting conditions 1 Retrofitting Enhancement of vacuum pump capacity 2 Retrofitting Installation of a membrane stage 3 Retrofitting Enhancement of blower capacity... 

After the manhole cover is removed, continue to test for combustible gas by lowering the sampling tube within 12 inches of the manhole or vault floor. If no flammable gas is found, purge the manhole with the power blower for the period of time based on the blower capacity and manhole configuration, following company procedures. 

The existing dust filter has a filtration area of 15 m (Figure 16.12) and is fitted with a fan and polyester needle-felt bags. From performance curves, the fan can extract 33.3m%iin of air at 150 mm H20 = 1.5kPa. At first glance, this appears to cover quite adequately the blower capacity of 21.7 m /min. However, transient effects and filtration efficiency also have to be evaluated. 

The data plotted in Figure 5-3 were actually not assembled until after the catastrophic pressure rise. The plant operators had not noticed the increase in reaction furnace pressure. Only when they tried to increase acid gas charge and ran short of air blower capacity did they realize something was amiss. 

Many FCCUs are coke-burn limited, which usually means they are limited by the regenerator combustion air blower. On most units the air blower is a low-head centrifugal compressor. Factors to look for in defining the cause of reduced blower capacity are ... 

Examination of Table 9.1 shows that the air provided by the plant (7 = 50dC, Gs = 0.1 kg/s) underestimated the minimum requirement by a factor of 14. Even at a temperature of 125dC, the minimum flow required was still five times that actually provided. Clearly, a combination of both higher temperature and greater blower capacity would be required to meet the drying specifications. A reasonable recommendation would be for a flow rate of 1 kg/s at 125dC at the point of delivery. This provides a safety factor of 2 over the tabulated (GJ m of 0-49 kg/s. 

It is important to know the total pressure drop Ap of the irrigated packed bed when designing packed columns for gas/liquid systems in counter-current flow of the phases. In absorption as weU as desorption processes, the total pressure drop Ap of the packing determines the blower capacity and thus the major part of the operating costs of the process. In rectihcation, the sum of the top pressure pT and the total pressure drop Ap gives the bottom pressure pw, which determines the bottom temperature tw- The bottom temperature, in turn, determines the effective temperature difference, at a given heating medium temperature, at which the reboiler in the distillation column must be operated. 

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