Equipment design compressors

Exact design criteria on equipment for handling acetylene is not readily available because of the great number of factors involved. However, recommendations have been made concerning the equipment, piping, compressors, flash arresters, and proper materials (69,92—94). 

The reciprocating, centrifugal and rotary-screw compressors described in the chapter covering this equipment design and selection are also used in refrigerant service. Sev-... 

F.L. Evans, Compressors and fans, in Equipment Design Handbook for Refineries and Chemical Plants, Gulf, Houston, 1979, Vol. 1, pp. 54-104. 

Rules are given for many types of equipment—from compressors, to distillation columns, to heat exchangers, to vessels. Such guidelines are useful in preliminary design calculations and cost estimates. 

Both the gas processing and gas storage system include valves and tube or pipes plus, depending on the system design, compressors, pressure relief valves, gauges and other equipment specific to the method of storage. 

Optimize the design problem in the previous exercise for two simultaneous objectives minimization of total shaftwork and minimization of total capital cost of major equipment items (compressor, turbo-expander and heat exchanger). The correlations for the capital cost of these can be taken from Section 8.4.2 of this... 

Through the years, equipment design has adapted to developments in catalysts, in other words more severe operating conditions, particularly at very low pressures. This situation has resulted in a substantial decrease in the maximum allowable pressure drop in the furnaces, exchangers and reactors. In fact, at a given pressure, the pressure drop conditions the dimensioning of the hydrogen recycle compressor, and hence its cost. 

Chapters 14 and 15 provide similar coverage on the details of the design of multistage and packed towers, and of pumps, compressors, and expanders, respectively. While some of this material may be a review for students, the recommendations for equipment design should be helpful. 

A compressor system, which is a simple arrangement of equipment designed to produce clean, dry, compressed air or gas for industrial applications, typically includes process piping, valves, a compressor, a receiver, heat exchangers, dryers, back pressure regulators, gauges, and moisture removal equipment. 

Most rotating equipment includes electric motors or steam dryers that generate noise at a constant frequency. Air cooler fans are a source of noise that can be reduced by lowering the fan speed and increasing the number of blades. Pump motor noise can be reduced by including a shroud or fan cover that is accurately lined. Centrifugal compressor noise reduction can be achieved by blade design and the use of compressor pulsation noise reduction, silencers, and vibration isolation. 

A compressor is typically a specially designed device, and comes with far less surplus capacity than other process components. As a result compressors merit great care in specification of flow, inlet pressure, and discharge pressure. Similarly, the control system and equipment need to be carefully matched to provide turndown with maximum efficiency. 

Most ethylene plants operate continuously with the expanders operating at or near design conditions. If necessary, due to their unique design characteristics, radial inflow turboexpanders can accommodate a wide range of process conditions without significant losses in thermal or mechanical efficiency. Expanders may be loaded with booster compressors, gear-coupled generators, dynamometers, or other in-plant mechanical equipment such as pumps. In ethylene plants, turboexpanders are typically used in eitlier post-boost or pre-boost applications. 

Off-design performance of an expander-compressor set can be derived from the curves typically provided by tlie equipment manufacturer. Actual... 

The lubrication system for the turbine is designed to provide both lubrication and cooling. It is not unusual that in the case of many gas turbines the maximum temperatures reached in the bearing section is about 10-15 minutes after the unit has been shutdown. This means that the lubrication system should continue to operate for a minimum of 20 minutes after the turbine has been shutdown. This system closely follows the outline in API Standard 614, which is discussed in detail in Chapter 15. Separate lubrication systems for various sections of the turbine and driven equipment may be supplied. Many vendors and some manufacturers provide two separate lubrication systems One for hot bearings in the gas turbines and another for the cool bearings of the driven compressor. These and other lubrication systems should be detailed in the specifications. 

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