Maintenance compressors

Good Maintenance Practices Good operating or maintenance practices that improve overall efficiency. Insidation on liquefaction compressors Steam system maintenance Compressor maintenance... 

Exhibit 4-28 illustrates how compressor maintenance affects the size of the shelter or structure. Although operational access often determines floor space requirements, the height of a compressor house is strialy a function of maintenance. Consequently, the size of the maintenance area must permit the largest single item to pass unobstructed from one end of the building to the other and should be set as close to the operating level as possible. The centerline elevation of the hook that allows all items to pass through the maintenance area must be set. The hook elevation. 

Another important feature regarding reciprocating compressor maintenance is shown in Exhibit 4-35- A clear area must be provided in line with each compressor cylinder to permit cylinder removal during the maintenance cycle. The area between two machines must be common for both cylinders. 

Gas turbine driven centrifugal compressors are very efficient under the right operating conditions but require careful selection and demand higher levels of maintenance than reciprocating compressors. Compression facilities are generally the most expensive item in an upstream gas process facility. 

Filtration and water-knockout systems are used to clean up the gas before it enters a compressor. Cooling systems are sometimes required to maintain compressor discharge temperatures below 54°C to avoid damage to the pipeline s protective coatings. Automated compressor stations are typically staffed by maintenance and repair personnel eight hours per day, five days per week. Other stations are staffed on a 24-hour basis because personnel must start, stop, and regulate compressors in response to orders from the dispatch office. 

In selec ting the machines of choice, the use of specific speed and diameter best describe the flow. Figure 10-67 shows the characteristics of the three types of compressors. Other considerations in chemical plant service such as problems with gases which may be corrosive or have abrasive solids in suspension must be dealt with. Gases at elevated temperatures may create a potential explosion hazard, while air at the same temperatures may be handled qmte normally minute amounts of lubricating oil or water may contaminate the process gas and so may not be permissible, and for continuous-process use, a high degree of equipment rehability is required, since frequent shutdowns for inspec tion or maintenance cannot be tolerated. 

The magnitude of the air sterilization problem is seen from the usual needs of a highly aerobic fermentation where roughly 1 volume of air per volume of medium per minute may be used. For a factoiy with 20 fermenters of 100,000 1 (3500 fH) each, 2 million Em (70,000 ftVm) of air is handled. Very large compressors are used, and at least two are required so that one can be down for maintenance. 

Turbine and compressor online performance for use in equipment predictive maintenance. 

Standard turboexpander-compressor sets designed and manufactured by competent manufactureres embody many of the reliability improvement and maintenance cost reduction features inherent in API (American Petroleum Institute) standards for other turbomachines. To achieve close compliance, however, the owner/purchasers must know their specific needs or requirements. Nevertheless, it may not be practical, feasible, or economically justified to achieve full compliance with API specifications, which were generally devised without giving thought to the peculiarities of turboexpanders and their sometimes differing operating environments. 

The oldest of the various systems was commissioned when the plant first opened in 1985 it has been operating continuously 24 hours a day. The turboexpander-compressor set has proved its durability, requiring only lube oil skid maintenance prior to its first overhaul after many years of operation. 

The ejector can first be identified as having no moving parts (see Figure i-10). It is used primarily for that feature as it is not as efficient as most of the mechanical compressors. Simplicity and the lack of wearing parts contribute to the unit s inherent reliability and low-maintenance expense. 

The basis for evaluation of piston speed varies throughout industry. This indicates that the subject is spiced with as much emotion as technical basics. An attempt to sort out the fundamentals will be made. First, because there are so many configurations and forms of the reciprocating compressor, it would appear logical that there is no one piston speed limit that will apply across the board to all machines. The manufacturer is at odds with the user because he would like to keep the speed up to keep the size of the compressor down, while the user would like to keep the speed down for reliability purposes. As is true for so many other cases, the referee is the economics. An obvious reason to limit the speed is maintenance... 

Pistons may be of segmented construction to permit the use of one-piece wear bands. One-piece wear bands are a requirement in API 618. Pistons have a problem in common with humans—a weight problem. Weight in a piston contributes directly to the compressor shaking forces and must be controlled. For this reason, aluminum pistons are often found in larger low pressure cylinders. Hollow pistons are used but can pose a hazard to maintenance personnel if not properly vented. If trapped, the gas will be released in an unpredictable and dangerous manner when the piston is dismantled. 

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