Process equipment motors

In years past, caustic soda plants generally prohibited the use of any aluminum parts on any processing equipment, motors, instruments, etc., because aluminum is aggressively attacked by any fumes or drips of caustic soda. However, during a major expansion in the late 1960s, refrigeration units were purchased that were equipped with safety relief valves made with aluminum bodies. During this very active period of construction,... 

Size of equipment as a function of the average horsepower of process equipment motors (pumps, agitators, compressors). 

Figure 12 shows the plan and elevation views of a process unit piping (9). A dmm is supported off the piperack. Heat exchangers are located far enough back from the support columns so that they are accessible and their shell covers can be removed. Pumps are located underneath the piperack, but sufficient room is provided for maintenance equipment to access the motors and to remove the pump if necessary. The motor is always oriented away from the process equipment and located on that side of the piperack. Instmment valve drops are shown supported from the columns. The instmment trays themselves mn on the outside of the support columns. Flat turns are only made from the outside position of the piperack. Nozzle-to-nozzle pipe mns are made whenever possible. Larger lines are located on the outside of the piperack. Connections to nozzles above the rack are made from the top... 

The principal technological changes in the engineering control of air pollution were the perfection of the motor-driven fan, which allowed large-scale gas-treating systems to be built the invention of the electrostatic precipitator, which made particulate control in many processes feasible and the development of a chemical engineering capability for the design of process equipment, which made the control of gas and vapor effluents feasible. 

The compressor or blower installation in a typical refinery or chemical process unit is not out-of-doors completely. Some form of shelter often is provided, ranging from only a roof to a completely closed building. When process equipment such as a centrifugal gas compressor, which is not hazardous in normal operation, is present in the shelter, the hazard classification depends on the extent to that which the shelter restricts ventilation. The extent of the shelter provided determines the area classification and the type of motor enclosure that should be applied. 

High-temperature wire and cable irt-solution, motor-lead insulation chemical process equipment... 

Because of the magnitude of the task of preparing the material for this new edition in proper detail, it has been necessary to omit several important topics that were covered in the previous edition. Topics such as corrosion and metallurgy, cost estimating, and economics are now left to the more specialized works of several fine authors. The topic of static electricity, however, is treated in the chapter on process safety, and the topic of mechanical drivers, which includes electric motors, is covered in a separate chapter because many specific items of process equipment require some type of electrical or mechanical driver. Even though some topics cannot be covered here, the author hopes that the designer will find design techniques adaptable to 75 percent to 85-1- percent of required applications and problems. 

The process designer and project engineer should classify the various areas of a plant following NEPA-70, Article 50528.29 order to advise the electrical and other project team members of the degree of electrical hazards anticipated. The appropriate equipment (motors, instruments, conduit, wiring, etc.) should be specified according to NEPA-70, Article 500 and others as applicable, the ASME Code and the API Code as appropriate. See NEPA-497A and... 

Building 5—A motor control center (MCC) constructed of unreinforced masonry. An electrician spends 1 hour a day monitoring equipment in the MCC. The MCC provides power for process equipment critical to the continued operation of the facility. Critical power for safety shutdown equipment for both Process Units 1 and 2 is located in Building 5. 

Cooling load calculations should be done on a room-by-room basis. Careful attention should be given to process equipment loads because these can be significant heat generators. In calculating this load, consideration should be given to motor load, convection, and radiation from heated vessels and thinly insulated process and utility piping. Attention... 

Our home circuit breakers, or fuses, are, of course, trips to prevent overheating electric circuits or electric motors. The only difference is that at work, our electric circuit breakers have a built-in time delay. This is needed to allow the motor driver to overcome the starting torque inherent in most large pieces of rotating process equipment. 

Applications. The kinds of motors that are being used successfully with particular kinds of. chemical process equipment are identified in Table 4.1. As many as five kinds of AC motors are shown in some instances. The choice may be influenced by economic considerations or local experience or personal preference. In this area, the process engineer is well advised to enlist help from electrical experts. A checklist of basic data that a supplier of a motor must know is in Table 4.2. The kind of enclosure may be specified on the last line, operating conditions. 

Centrifugal, motor-driven pumps are the only type of process equipment that is relatively cheap. 

Electrical applications include wire and cable insuladon, insulation for motors and generators, and high frequency electronic uses. Chemical equipment such as gaskets, pump and valve packing, and valve parts are also fabricated. Low friction and anti-stick applications include non-lubricated bearings and linings for bakery trays and home and institutional food processing equipment. 

Process Area Motors (from Equip. Acct.) 383 hp Approx. 383 kVA... 

All the major process equipment, such as vessels, reactors, columns, furnaces, heat exchangers, coolers, pumps, compressors, motors, fans, turbines, filters, centrifuges, dryers, etc., including field fabrication and testing if necessary ... 

The voltage at which the supply is taken or generated will depend on the demand. In the United States, power is usually transmitted over long distances at 135, 220, 550, or 750 kV Local substations step the power down to 35 to 69 kV for medium voltage transmission and then to 4 to 15 kV local distribution lines. Transformers at the plant are used to step down the power to the supply voltages used on site. Most motors and other process equipment run on 208 V 3-phase power, while 120/240 V single phase power is used for offices, labs, and control rooms. 

Calculate the horsepower (HP) needed to process a 8500-acfm gas stream from an incinerator. The pressure drop across the various pieces of process equipment has been estimated to be 8.4 in. H2O. The pressure loss for duct work, elbows, valves, and so on, and expansion-contraction tosses are estimated at 5.8 in. H2O. Assume an overall fan-motor efficiency of 58%. 

Preventing the overloading of processing equipment, such as grinders and conveyors. Consider installing overload protection devices on drive motors. 

The operating speed characteristics of the process equipment dictate the type of motor and control to be applied. Most drives operate at a speed lower than that of the motor, thus requiring some form of speed reduction. The gearing may be via direct-cpnnected coupled motor or a speed reducer may be used. Variable or adjustable speed performance must be definitely established as to speed range, degree of speed adjustment, and load requirements at all speeds. Constant-torque or constant-horsepower drives both require variable-speed or multispeed motors with suitable control equipment. 

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