Work pressure

A somewhat different type of high pressure reaction vessel is illustrated in Figs. VI, 4, 3-5. This is designed for hydrogenation reactions at working pressures from 1 to 300 atmospheres (4,500 lb. per square inch) and at temperatures from atmospheric up to 400°. Fig. VI, 4, 3... 

The original pressure should not be more than 2,000 lb. per sq. in. if the maximum working pressure for the autoclave is 5,000 lb. The full operating pressure is not applied at the beginning because the pressure will rise as the bomb is heated thus at 256°, the pressure will be 1 - 8 times that at 20°. 

Hoses must be made for anhydrous ammonia service 2500 kPa (348 psig) working pressure and stamped for this service. In locations where hoses may be abraded, wke braid armored or reinforced hose types should be used. Hose ends should have boss or other acceptable ak kon ferruled couplings. 

These alloys are available in the cast form only. Pipe and fittings are cast with the upset ends being joined by split flanges. IntegraUy cast flanged pipe is also available. Allowable working pressures cannot be... 

These pipe walls are adequate for the rated working pressure plus a surge allowance of 100 Ihf/in . For the effect of laying conditions and depth of hiiry, see ANSI A21.51. 

Chemical-Porcelain Pipe Made of dense, nonporous material and fired at 1230°C (2250°F), chemical-porcelain pipe, fittings, and valves are inert to all acids except hydrofluoric but are not usually recommended for alkalies. Surfaces, except when ground for gasketing, are usually glazed for easy cleaning. Working pressures of 0.3 to 0.7 MPa (50 to 100 Ibftin") are recommended for valves and piping. Temperatures of 200°C (400°F) or more can be used, but sudden thermal shocks must be avoided. 

Joining material used in joints Working temperatures, < F Maximum working pressure, Ibf/in ... 

Percent of steel base price, 1500-lbf/in working pressure... 

Pressures can be specified at any level below the safe working pressure of the column. The condenser pressure will be set at 275.8 kPa (40 psia), and all pressure drops within the column will be neglected. The eqnihbrinm curve in Fig. 13-35 represents data at that pressure. AU heat leaks will be assumed to be zero. The feed composition is 40 mole percent of the more volatile component 1, and the feed rate is 0.126 (kg-mol)/s [1000 (lb-mol)/h] of saturated liquid (q = 1). The feed-stage location is fixed at stage 4 and the total number of stages at eight. 

Gas pressurized Monitor tank level and provide interlock for feed feed shut-off overpressurizes, alternate fluid delivery system (e.g., pump) centrifuge system when feed vessel delivery gas pressure to maximum safe empties working pressure of downstream system (e.g., pressure regulation) Restrict feed flow rate to be consistent with vent capacity Ensure adequate vent capacity for maximum possible gas flow ... 

In many applications a pressure vessel may be tested for safety simply by hydraulic testing to a pressure that is higher - typically 1.5 to 2 times higher - than the normal operating pressure. Steam boilers (Fig. 16.7) are tested in this way, usually once a year. If failure does not occur at twice the working pressure, then the normal operating stress is at most one-half that required to produce fast fracture. If failure does occur under... 

The failure took place in a large water-tube boiler used for generating steam in a chemical plant. The layout of the boiler is shown in Fig. 13.1. At the bottom of the boiler is a cylindrical pressure vessel - the mud drum - which contains water and sediments. At the top of the boiler is the steam drum, which contains water and steam. The two drums are connected by 200 tubes through which the water circulates. The tubes are heated from the outside by the flue gases from a coal-fired furnace. The water in the "hot" tubes moves upwards from the mud drum to the steam drum, and the water in the "cool" tubes moves downwards from the steam drum to the mud drum. A convection circuit is therefore set up where water circulates around the boiler and picks up heat in the process. The water tubes are 10 m long, have an outside diameter of 100 mm and are 5 mm thick in the wall. They are made from a steel of composition Fe-0.18% C, 0.45% Mn, 0.20% Si. The boiler operates with a working pressure of 50 bar and a water temperature of 264°C. 

The hoop stress in the tube under the working pressure of 50 bar (5 MPa) is 5 MPa X 50 mm/5 mm = 50 MPa. Creep data indicate that, at 900°C and 50 MPa, the steel should fail after only 15 minutes or so. In all probability, then, the failure occurred by creep rupture during a short temperature excursion to at least 870°C. 

Rec rocating cylinder water jackets are tested at IA times specified working pressure for the cooling fluid. API 618 recommends a pressure of no less than 115 psig. 

The hydrostatic testing is the first test used on the lube system. The system is tested while assembled or partially assembled, based on the particular system. A test pressure of VA times the maximum allowable working pressure, a minimum of 20 psi for the oil side, is used for the test. For the oil-wetted parts, the test fluid should be light oil, which is normally the recommended lubricant for the compressor train. The test period is the length of time needed to inspect for leaks, or a minimum ol thirty minutes. Acceptance is based on the lack of leaks as visually observed or the lack of a drop in the test pressure. 

Catastrophic failure of containers as cryogen evaporates to cause pressure build-up within the vessel beyond its safe working pressure (e.g. pressures <280 000 kPa or 40 600 psi can develop when liquid nitrogen is heated to ambient temperature in a confined space). 

Dangerous goods only transported if the letter Y appears in appropriate columns of Approved Carriage list and Schedules 5 and 6 are complied with, and tank pressures do not exceed the maximum working pressure as per certifications. 

Do not exceed safe working pressure consider need for safety relief devices. 

Hoses to be indelibly marked to indicate the substances for which it is intended, its safe working pressure, proof-test pressure, date tested, and maximum or minimum service temperature. 

AMD 1 Transportable gas container valves. Part 1 Industrial valves for working pressures up to and including 300 bar (AMD 7641J dated 15 May 1993 Partially replaced BS 341. Part 1 1962 and BS 341 Paid 2 1963... 

By virtue of its chemical and thermal resistances, borosilicate glass has superior resistance to thermal stresses and shocks, and is used in the manufacture of a variety of items for process plants. Examples are pipe up to 60 cm in diameter and 300 cm long with wall tliicknesses of 2-10 mm, pipe fittings, valves, distillation column sections, spherical and cylindrical vessels up 400-liter capacity, centrifugal pumps with capacities up to 20,000 liters/hr, tubular heat exchangers with heat transfer areas up to 8 m, maximum working pressure up to 275 kN/m, and heat transfer coefficients of 270 kcal/hz/m C [48,49]. 

Maximum Allowable Working Pressure -As defined in the construction codes for pressure vessels, the maximum allowable working pressure depends on the type of material, its thickness, and the service conditions set as the basis for design. The vessel or equipment may not be operated above this pressure, or its equivalent stress at any other metal, temperature. However, ANSI B31.3, Petroleum Refinery Piping Code, permits variations above the maximum allowable working pressure, as follows ... 

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