API standards

Design and Construction ofiEP-Gas Installations at Marine Terminals, Natural Gas Processing Plants, Refineries, Petrochemical Plants, and Tank Farms, API Standard 2510, 4th ed., American Petroleum Institute, Washington, D.C., Dec. 1978. 

Slurry contains 35 g of API Standard Evaluation Base Clay per 350 cm saturated salt solution. 

The pump-mounting feet are located close to the centerline. As a result, the pump thermal growth is uniform on both sides of the centerline, leading to minimal distortions. The design is governed by the American Petroleum Institute (API) standard 610, "Centrifugal Pumps for General Refinery Service" (30). 

Tank Shell. Another example of where thickness is set by minimums for fabricabihty but not for strength is in small-diameter tanks. For example, a water storage tank built using a steel of an allowable stress of 20,000 psi (138 mPa), 9 ft (3 m) in diameter by 21-ft (7-m) high, requires a shell thickness to resist hoop stress of only 0.023-in. (0.58-mm) thick. However, if built to API Standard 650, the shell would be fabricated at least 0.1875-in. (4.76-mm) thick. The code requires this thickness so that when fabrication, welding, and tolerances are considered, a tank of acceptable quaUty and appearance meeting the requirements of most services in most locations is provided. 

API Standard 2610, "API Design, Constmction, Operation, Maintenance and Inspection of Terminal and Tank FaciUties," American Petroleum Institute. 

American Petroleum Institute (API) Standard 610, Centrifugal Pumps for Refinery Service... 

API standards for balanced and unbalanced seals are good guidelines too low a pressure for a balanced seal may encourage face lift-off. 

The Underwriters Standards overlap API, but include tanks that are too small for API Standards. Undei writers Standards are, however, not as detailed as API and therefore put more responsibility on the designer. They do not specify grades of steel other than requiring weldability. Designers should also place their own limits on the diameter (or thickness) of vertical tanks. They can obtain guidance from API. 

Fixed-roof atmospheric tanks require vents to prevent pressure changes which would othei wise result from temperature changes and withdrawal or addition of liquid. API Standard 2000, Venting Atmospheric and Low Pressure Storage Tanks, gives practical rules for vent design. The principles of this standard can be applied to fluids other than petroleum products. Excessive losses of volatile liquids, particularly those with flash points below 38°C (100°F), may result from the use of open vents on fixed-roof tanks. Sometimes vents are manifolded and led to a vent tank, or the vapor may be extracted by a recov-eiy system. 

An effective way of preventing vent loss is to use one of the many types of variable-volume tanks. These are built under API Standard 650. They may have floating roofs of the double-deck or the singledeck type. There are hfter-roof types in which the roof either has a sldrt moving up and down in an annular hquid seal or is connected to the tank shell oy a flexible membrane. A fabric expansion chamber housed in a compartment on top of the tank roof also permits variation in volume. 

Pressure Tanks Vertical cylindrical tanks constructed with domed or coned roofs, which operate at pressures above several hundred pascals (a few pounds per square foot) but which are still relatively close to atmospheric pressure, can be built according to API Standard 650. The pressure force acting against the roof is transmitted to the shell, which may have sufficient weight to resist it. If not, the uplift will act on the tank bottom. The strength of the bottom, however, is limited, and if it is not sufficient, an anchor ring or a heavy... 

As the size or the pressure goes up, curvature on all surfaces becomes necessary. Tariks in this category, up to and including a pressure of 103.4 kPa (15 Ibf/in"), can be built according to API Standard 620. Shapes used are spheres, ellipsoids, toroidal structures, and circular cylinders with torispherical, elhpsoidal, or hemispherical heads. The ASME Pressure Vessel Code (Sec. TII of the ASME Boiler and Pressure Vessel Code), although not required below 103.4 kPa (15 Ibf/in"), is also useful for designing such tanks. 

The API Standard gives considerable information on the construction and safety features of such installations. It also recommends minimum distances from property hnes. The user may wish to obtain added safety by increasing these distances. 

Shell and Tube Heat Exchangers for General Piefineiy Seivices, API Standard 660, 4th ed., 1982, is published by the American Petroleum Institute to supplement both the TEMA Standards and the ASME Code. Many companies in the chemical and petroleum processing fields have their own standards to supplement these various requirements. The Jnterrelation.ships between Codes, Standards, and Customer Specifications for Proce.ss Heat Tran.sfer Equipment is a symposium volume which was edited by F. L. Rubin and pubhshed by ASME in December 1979. (See discussion of pressure-vessel codes in Sec. 6.)... 

FIG. 11-44 Typical construction of a tube bundle with plug headers (1) tube sheet (2) plug sheet (3) top and bottom plates (4) end plate (5) tube (6) pass partition (7) stiffener (8) plug (9) nozzle (10) side frame (11) tube spacer (12) tube-support cross member (13) tube keeper (14) vent (15) drain (16) instrument connection. (API Standard 661.)... 

NFPA 30 and API Standard 2000 provide gmdance for design of overpressure protec tion involving storage tanks that operate at or near atmospheric pressure. In particular, NFPA 30 focuses on flammability issues, while API 2000 addresses both pressure and vacuum requirements. The ASME code (Sections I and TII) and API RP 520 are the primaiy references for pressure rehef device sizing requirements. 

Low-Pressure Tanks (below 15 psig) Low-pressure storage tanks for highly hazardous toxic materials should meet, as a minimum, the American Petroleum Institute (API) 620 Standard, Recommended Rules for the Design and Construc tion of Large Welded, Low-Pressure Storage Tanks (API Standards). This standard covers... 

The graph below is a family eurve for a petroleum-refining pump meeting API standards (Figure 7-16). 

Lube oil units are typieally available in two versions the manu-faeturer s standard or in aeeordanee with API Standard 614. The major eomponents of a unit are the oil tank, auxiliary oil pump, double filter and, seleetively, one or two oil eoolers. All eomponents of the smaller units are mounted on a eommon bedplate, separated from the other eomponents. The oil ean be heated by an eleetrieal or steam-powered heating unit. The neeessary instrumentation is a standard supply item and, if requested, the switehes and motors ean be prewired. The main and auxiliary oil pumps are driven by different types of drivers (e.g., one by an eleetrie motor and the other by either a small steam turbine or by direet eonneetion to the shaft end of a major maehine easing in the turbotrain). 

More often than not, a manufaeturer s standard lubrieation system ineorporates many of the features inherent in the API standards. Nevertheless, when speeifieally required by eustomer speeifieation, the lubrieation system ean be designed to eomply almost fully with the applieable API standards. 

An examination of the above standards as they apply to the gas turbine and its auxiliaries are further examined in this section. The ASME B 133.2 basic gas turbines and the API standard 616, gas turbines for the petroleum, chemical, and gas industry services are intended to cover the minimum specifications necessary to maintain a high degree of reliability in an open-cycle gas turbine for mechanical drive, generator drive, or hot-gas generation. The standard also covers the necessary auxiliary requirements directly or indirectly by referring to other listed standards. 

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. 

This standard API Standard 613 covers special purpose gears. They are defined as gears, which have either or both actual pinion speeds of more than 2900 rpm and pitchline velocities of more than 5000ft/min (27 meters/sec). The standard applies to helical gears employed in speed-reducer or speed-increaser units. 

This API Standard 614 standard eovers the minimum requirements for lubrieation systems, oil shaft sealing systems, and related eontrol systems for speeial purpose applieations. The terms are fully defined, referenees are well doeumented and basie design is deseribed. Details of the lubrieation system are presented in Chapter 15. 

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