Reactor piping

Piping systems Miscellaneous or unknown Storage tanks Reactor piping systems Process holding tanks Heat exchangers Valves... 

The most frequent operational problems in waste water ozonation systems are foaming and the formation and precipitation of calcium oxalate, calcium carbonates and ferrous hydroxide (Fe(OH)3) which may easily clog the reactor, piping and valves and also damage the pumps. 

Several accident scenarios are proposed which are initiated by the chemical plant. These scenarios include intra-reactor piping system failures, as well as reaction chamber failures. The proposed accidents are summarised in Table 1. 

Intra-reactor piping failure Reaction chamber rupture Bunsen failure Reactant flow pipe failure Product flow pipe failure Single reaction chamber failure Bunsen reactor Section 2 or Section 3 Section 2 or Section 3 Section 2 or Section 3... 

Figure 5-7 Reactor piping settling leg arrangement. Courtesy of the U.S. Department...

As shown in Fig. 18.23, dry liquid feed containing olefins and isobutane is charged to a combined reactor-settler. In this example, the reactor uses the principle of a differential gravity head to circulate through a cooler before contacting a highly dispersed hydrocarbon feed in the reactor pipe. The hydrocarbon phase, generated in the settler, is sent to a fractionator, which separates LPG-quality propane, isobutane recycle, n-butane, and alkylate products. A small amount of dissolved catalyst is also removed from the propane product by a small stripper tower. 

Tada, H., Paris, P.C. and Gamble, R.M., (1979), Stability analysis of circumferential cracks in reactor piping systems. U.S. Nuclear Regulatory Commission Report, NUREG/CR-0838. 

In the fluidized-bed (fluid catalytic cracking) units, the cracking reactions take place in the riser to form products, including coke. In the riser, the catalyst and the feedstock and products rise up the reactor pipe, and because the reactions are predominantly endothermic, the reaction temperature declines from bottom to top. At the top of the riser, the mixture... 

The term "carbon residue" is used to designate the carbonaceous residue formed after evaporation and pyrolysis of a petroleum product. The residue is not entirely composed of carbon, but is a coke that can be further changed by pyrolysis. The term is used to indicate the relative tendency of a residue to form carbon deposits that may foul reactor pipes. 

Tubular reactors, see Fig. 3.18(b), are used to make film grade LDPE. The flow through the reactor pipe is turbulent, so there is good mixing in the radial direction however, the blunt velocity profile limits the back mixing that occurs. Free radical initiators are injected into the flow at various spots along the path to cause... 

In the Swift process (Figure 12.14), phosphoric acid (50% P2O5) and liquid ammonia react in a two-fluid nozzle, which discharges into a reactor pipe. The mixture of finely divided MAP and steam is injected into a cooling tower where a countercurrent airstream carries away the water vapor formed by the heat of reaction and cools the product, The product moisture content is 3%-5%. The Nissan process is also a spray tower process, in which droplets of phosphoric acid react with ammonia in an ascending airstream. 

Corrosivity to ferrous reactors, piping, and storage vessels when producing amphoterics containing high levels of sodium chloride. 

A manually operated secondary fog spray system is attached to the lower parts of the charge and discharge elevators and will spray water on the reactor front and rear face piping Here it will serve to cool fuel elements should they become lodged in the reactor piping It will also settle particulate matter should a uranium fire occur ... 

There are no "nozzles for an even SOj/air distribution over all pipes. The pressure drop over the 6 m pipe can be calculated with the well-known Fanning equation for turbulent flow. For an SOa/air velocity of 30 m/s in an empty reactor pipe a value of 0.025 bar is found. In experiments with air and organic film (without any sulphonation reaction) a pressure drop of 0.1 bar was measured at an air velocity of 30 m/s. The interaction of the air with liquid film ripples and waves causes an increase of about a factor 4 in the pressure drop compared with the empty tube. Under real sulphonation conditions the pressure drop measured becomes even greater at 0.25 bar, due to the sharp increase of viscosity at high conversions. 

NU G/CP-0155, "Proceedings of the seminar on leak-before-break in reactor piping and vessels" held in Lyon, France, October 9-11,1995", US Nuclear Regulatory Commission, April 1997. 

Relief valves are usually furnished as part of the reactor piping. system and should be located in accordance with the arrangements shown in Chapters 5 (Drums) and 10 (Towers). 

The activation of ojgrgen in the primary coolant results in the formation of N-16, which is a strong gamma emitter. Due to its short half-life of 7.1 seconds, N-16 is not a concern outside the containment. N-16 is the predominant contributor to the activity in the reactor coolant pumps, steam generators and reactor piping during operation. The activity in each component depends on the transit time to the component and the residence time. 

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