Maximum pressure after

A confined explosion occurs in a confined space, such as a vessel or a building. The two most common confined explosion scenarios involve explosive vapors and explosive dusts. Empirical studies have shown that the nature of the explosion is a function of several experimentally determined characteristics. These characteristics depend on the explosive material used and include flammability or explosive limits, the rate of pressure rise after the flammable mixture is ignited, and the maximum pressure after ignition. These characteristics are determined using two similar laboratory devices, shown in Figures 6-14 and 6-17. 

Maximum pressure after decomposition the maximum pressure obtainable in a closed vessel this pressure is a function of the adiabatic temperature rise and the specific gas production. 

Figure 11 shows that the agreement between the prediction of non-dlmenslonal maximum pressure after Snldle and Archard and that according to a numerical solution with the half-Sommerfeld boundary condition Is excellent. 

Effectiveness of the bubbler condenser is essential for fulfilling the safety function relating to limiting the maximum pressure after a DBA occurrence and to preventing the release of radioactive products to the environment. To fulfill this objective, efficient condensation of steam in water trays need to be assured without excessive bypassing of trays. 

A 3,500-gal reaetor with styrene monomer undergoes adiabatie polymerization after being heated inadvertently to 70°C. The maximum allowable working pressure (MAWP) of the reaetor is 5 bar absolute. Determine the relief vent diameter required. Assume a set pressure of 4.5 bara and a maximum pressure of 5.4 bara. Other data and physieal properties are given as follows [12] ... 

If the outlet or discharge pressure is lowered further, the pressure upstream at the origin will not detect it because the pressure w ave can only travel at sonic velocity. Therefore, the change in pressure dow nstream w ill not be detected upstream. The excess pre.ssure drop obtained by lowering the outlet pressure after the maximum discharge has been reached takes place beyond the end of the pipe [3]. This pressure is lost in shock waves and turbulence of the jetting fluid. See References 12, 13, 24, and 15 for further expansion of shock waves and detonadon waves through compressible fluids. 

Where D is cubic inches of oil discharge Pi is pre-charge pressure in psi P2 is system pressure after Volume D has been discharged P3 is maximum system pressure at full accumulator charge Vi is catalog rated gas volume, in cubic inches and 0.95 is assumed accumulator efficiency. 

Freeder, B. G. et al., J. Loss Prev. Process Ind., 1988, 1, 164-168 Accidental contamination of a 90 kg cylinder of ethylene oxide with a little sodium hydroxide solution led to explosive failure of the cylinder over 8 hours later [1], Based on later studies of the kinetics and heat release of the poly condensation reaction, it was estimated that after 8 hours and 1 min, some 12.7% of the oxide had condensed with an increase in temperature from 20 to 100°C. At this point the heat release rate was calculated to be 2.1 MJ/min, and 100 s later the temperature and heat release rate would be 160° and 1.67 MJ/s respectively, with 28% condensation. Complete reaction would have been attained some 16 s later at a temperature of 700°C [2], Precautions designed to prevent explosive polymerisation of ethylene oxide are discussed, including rigid exclusion of acids covalent halides, such as aluminium chloride, iron(III) chloride, tin(IV) chloride basic materials like alkali hydroxides, ammonia, amines, metallic potassium and catalytically active solids such as aluminium oxide, iron oxide, or rust [1] A comparative study of the runaway exothermic polymerisation of ethylene oxide and of propylene oxide by 10 wt% of solutions of sodium hydroxide of various concentrations has been done using ARC. Results below show onset temperatures/corrected adiabatic exotherm/maximum pressure attained and heat of polymerisation for the least (0.125 M) and most (1 M) concentrated alkali solutions used as catalysts. 

Compute the theoretical maximum pressure obtained after igniting a stoichiometric quantity of methane and oxygen in a spherical vessel that is 1.5 ft in diameter. Assume an initial pressure of 1 atm. 

Relation 9.77 is usually called the Washburn equation [55,237], One should consider it as a special case of the fundamental Young-Laplace equation [3,9-11], Washburn was the first to propose the use of mercury for measurements of porosity. Now, it is a common method [3,8,53-55] of psd measurements for a range of sizes from several hundreds of microns to 3 to 6 nm. The lower limit is determined by the maximum pressure, which is applied in a mercury porosimeter the limiting size of rWl = 3 nm is achieved under PHg = 4000 bar. The measurements are carried out after vacuum treatment of a sample and filling the gaps between pieces of solid with mercury. Further, the hydraulic system of a device performs the gradual increase of PHg, and the appropriate intmsion of mercury in pores of the decreasing size occurs. 

For example for the preparation of a 15 cm long, 4.6 mm i.d. stainless tube column, 2.5 g of octadecyl-bonded silica gel was suspended in 25 ml of hexanol-methanol mixture, and kept in an ultrasonic bath for a few minutes to remove air. After the reservoir was filled with the slurry, methanol was pumped in at 10 ml min -1 under constant pressure, 45 MPa (450 bar). After the replacement of slurry solvent by methanol, the flow was stopped and the pressure allowed to drop. When 0 MPa was reached the reservoir was removed. Then, 20 ml of water was added and methanol was again pumped in under the same conditions as before. Again, the flow was stopped and the pressure allowed to drop until it reached 0 MPa. The pre-column was removed and the analytical column closed. The maximum pressure that can be applied in the filling stage is based on the pore size, particle shape, and purity of the silica gel. This reproducible packing procedure is performed at constant temperature by using a water bath (60-BO °C). 

At the start of the experiment, 11.5 g of feedstock resin is placed into the cylinder and the piston is inserted. The resin is then allowed to warm up to the preset cylinder temperature. In general, 10 minutes is adequate for thermal equilibration as measured by density fluctuations. The position of the piston is then recorded for each pressure setting, starting at the lowest and increasing to the maximum pressure. The piston position is recorded only after movement ceases. 

On running the program,the Performance Criteria are first printed out and then the separation ratio of the critical pair is asked for on the monitor screen. After typing in the appropriate value, the capacity ratio of the first peak of the critical pair followed by the capacity ratio last eluted peak peak are then requested. The request procedure continues until all the necessary information has been entered after which the program runs. Some care must be taken when entering the minimum pressure, maximum pressure and pressure increment. If the range is made too large and the increment too... 

This pressure P, divided by the charge density (defined as the volume of the chge divided by the volume of the bomb), gives the maximum pressure of the expl in its own volume after elimination of cooling-surface influence... 

For examination of an expl a charge(usually 50 to 300 g) is placed inside the bomb, and, after closing the lid, the air ib evacuated by means of a vacuum pump. Then foe chge Is fired electrically and the pressure diagram ia obtained. Method of computation of results is given in Ref 2. The result thus obtained ia termed foe "maximum pressure of the explosive in its own volume" ... 

Figure 3. Typical trace during inflation and deflation of a BLM by hydrostatic pressure as a function of time. A, beginning of infusion B, at maximum pressure difference C, infusion stopped D, withdrawal started. The shoulder after point B was caused by the formation of a bubble...

However, it seems that the magnitude of the repulsive force do not increase significantly as the pressure increases so that eventually, it becomes subdued by the continuous increase in the solvating power causing the overall extraction efficiency to increase once again after 225 bar. After 225 bar, we believe that the efficiency will increase continuously. This is substantiated by an earlier work of Lai [15] where the effect of pressure on the extraction efficiency of the quaternary ammonium ion from the MCM-41 matrix has been studied. In that work, the maximum pressure studied is 350 bar and it was found that the efficiency increases as the pressure increases in the range of 225-350 bar. 

THE VENDOR SHALL GUARANTEETHE MECHANICAL OPERATION OF THE EGUPMENT AND SYSTEM PROVIDED FOR A MINIMUM OF ONE YEAR AFTER START-UP. HLR EXPECTS PROCESS GUARANTEES ON THE SPECIFIED DISTILLATION RATES. CONDENSER PmFORMANCE.AM> MAXIMUM PRESSURE DROPS. ENTRAINMENT, AIR LEAKAGE RATES AND UTILITY CONSUMPTIONS SHALL BE SPECIFIED. ALLPROOUCT AND PROCESS SPECIFICATIONS WHICH THE VENDOR CANNOT GUARANTEE SHALL BE ENUMERATED. 

Ref RocketEncycl(1959), 14,62,140-1,163-4 596 Note It may be mentioned that if the maximum pressure in a rocket(or Jato) motor occurs after 80% of the total burning time it is sometimes referred to as the break-up pressure... 

Thus, we seek an asymptotic solution of the one-dimensional gasdynamic equations for a given pressure evolution curve, f(t/r), which is characterized by a sufficiently rapid pressure decrease. In a slightly different way, we may formulate the problem thus preserving the form of the dimensionless function f(t/r), we let the pressure duration go to zero and the maximum pressure to infinity, and look for the asymptotic solution—the distribution of the velocity, pressure and other quantities—after a finite time t, at a finite distance x. 

The character of the solution is independent of the concrete form of the pressure decrease law at the piston it(t), described by the dimensionless function f(t/r), only if / decreases fast enough for large values of t/r. In particular, it is unimportant whether / increases continuously or discon-tinuously at t < r. Even for a continuous increase of the gas pressure, a shock wave will form with a pressure amplitude of the order of the maximum pressure P at the piston. The shock wave velocity here is of order D yjP/p0, so that some small mass of gas, of order Dp0r r is subjected to a shock compression of amplitude P. After the pressure at the piston goes to zero this gas, extending into the vacuum, attains a velocity of order u0 y/P/p0, and at the time t it will be located at a point x — u0t tyfP/p0. So, for example, if f(t/r) = 1 at 0 < t < t/r < 1 and... 

---