Operating Pressure and Temperature

Testing should address the maximum operating temperature and pressure normally seen at the arrester location. This does not include certain pressure upsets (such as emergency shutdown) that produce unusually high system pressures. In many cases it may not be possible to design an arrester that will function effectively during upset conditions, and other protective measures should be considered (e.g., venting, suppression). 

It may be necessaiy to position flame arresters away from heat sources that could cause the allowable operating temperature of the arrester to be exceeded. Positioning must be made with due consideration of DDT constraints. See Table 5-4, which shows the relationship of run-up distance to 

Effect of Run-up Length on Propagation Velocity and Overpressure (CCPS 1993) 

Notr The above data are from tests in a straight 3-inch diameter pipe using a test gas consisting of 4.3 volume percent propane mixture in air, initially at 23 psia. 

Although the types of plant and equipment using flame arresters vary widely, they often have some common features. Frequently the system is 

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The first step is to have a complete and detailed description of the system, process, or procedure under consideration. This must include physical properties of the materials, operating temperatures and pressures, detailed flow sheets, instmment diagrams of the process, materials of constmction, other detailed design specifications, and so forth. The more detailed and up-to-date this information is, the better the result of the analysis. 

Lighting. An important appHcation of clear fused quartz is as envelop material for mercury vapor lamps (228). In addition to resistance to deformation at operating temperatures and pressures, fused quartz offers ultraviolet transmission to permit color correction. Color is corrected by coating the iaside of the outer envelope of the mercury vapor lamp with phosphor (see Luminescent materials). Ultraviolet light from the arc passes through the fused quartz envelope and excites the phosphor, produciag a color nearer the red end of the spectmm (229). A more recent improvement is the iacorporation of metal haHdes ia the lamp (230,231). 

Safety restrictions on allowable operating temperatures and pressures. 

Operating Temperature and Pressure Arresters are certified subject to maximum operating temperatures and absolute pressures normally seen at the arrester location. Arrester placement in relation to heat sources, such as incinerators, must be selected so that the allowable temperature is not exceeded, with due consideration for the detonation potential as run-up distance is increased. 

Assume theoretical stages and operating temperature and pressure. 

The HFBR core uses fully-enriched (93%) uranium oxide-aluminum cermet curved plates dad m aluminum. The core height is 0.58 m and the diameter is 0.48 m or a volume of 103.7 Itr. The U-235 weighs 9.83 kg supported by a grid plate on the vessel bottom. The coolant flow u downward. Iience. How reversal is necessary for natural circulation. It operating temperature and pressure are 60 ( and 195 psi. There are 8 main and 8 auxiliary control rod blades made of europium oxide (Lii A)o and dysprosium oxide (DyjO,), clad in stainless steel that operate in the reflector region. The scram system is the winch-clutch release type to drop the blades into the reflector region. Actuation of scram causes a setback for the auxiliary control rods which are driven upward by drive motors,... 

The ranges of mixture composition pins operating temperature and pressure are important. Unless a detonation flame arrester is used, it is essential to ensure that DDT will not occur after a flame enters the system. Even if a detonation flame arrester is used, it is important to use the correct type of arrester for the service. For example, if it is possible for a flame to approach from either direction, a bidirectional flame arrester must be selected. 

Data from an incinerator indicate a volumetric flow rate of 10,000 scfm (60°F, 1 atm). If the operating temperature and pressure of the unit are 1950°F and I atm, respectively, calculate tlie actual flow rate in cubic feet per minute. 

Allowing for pressure drop through piping, equipment, and control valves, establish the expected operating temperatures and pressures. 

For a given dehydrogenation system, i.e., operating temperature and pressure, thermodynamic theory provides a limit to the per pass conversion that can he achieved. A general formula is... 

Reaction conditions are generally mild, but they differ from one process to another. In the newer Unipol process (Eigure 12-1) used to produce both HDPE and LLDPE, the reaction occurs in the gas phase. Ethylene and the comonomers (propene, 1-butene, etc.) are fed to the reactor containing a fluidized bed of growing polymer particles. Operation temperature and pressure are approximately 100°C and 20 atmospheres. A single-stage centrifugal compressor circulates unreacted ethylene. The circulated gas fluidizes the bed and removes some of the exothermic reaction heat. The product from the reactor is mixed with additives and then pelletized. New modifications for gas-phase processes have been reviewed by Sinclair. ... 

In order to understand potential problems and solutions of design, it is helpful to consider the relationships of machine capabilities, plastics processing variables, and product performance (Fig. 1-10). A distinction has to be made here between machine conditions and processing variables. For example, machine conditions include the operating temperature and pressure, mold and die temperature, machine output rate, and so on. Processing variables are more specific, such as the melt condition in the mold or die, the flow rate vs. temperature, and so on (Chapter 8). 

Additionally, if a selected polymeric DCA is properly matched to a particular boiler operating temperature and pressure, there should be no increase in the total organic carbon (TOC) level of the steam. 

The hydrogenation of 3-hydroxy propan al (HPA) to 1,3-propanediol (PD) over Ni/SiOi/AEO, catalyst powder was studied by Professor Hoffman s group at the Friedrich-Alexander University in Erlagen, Germany (Zhu et al., 1997). PD is a potentially attractive monomer for polymers like polypropylene terephthalate. They used a batch stirred autoclave. The experimental data were kindly provided by Professor Hoffman and consist of measurements of the concentration of HPA and PD (Chpa< Cpd) versus time at various operating temperatures and pressures. 

In addition to the gasification agent (air, oxygen, or steam) and the gasifier operating temperature and pressure, other factors affect the chemical composition, heating value,... 

From a fire protection perspective, the primary issues are the gas or vapor handled, their size, operating temperature and pressure, auxiliary systems (lubricating oil), and value or importance to the process they serve. 

For the purpose of this review, it is assumed that for a given membrane at any specified operating temperature and pressure, the value of D /K6 for a given solute is independent of Xy 2> this assumption is not, and need not be, valid in all cases, but it is valid with respect to cellulose acetate membranes and many organic and inorganic solutes, including sodium chloride, in aqueous solutions. In any case, the above assumption does not restrict the practical scope of this analysis (113). 

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