Piping modifications

For this kind of case, a modification of the dilution method is being developed. Instead of using an external fixed-geometry measurement chamber, a suitable part of the process, e.g. a stretch of pipe, is used. A radiation detector is mounted on the outside of the pipe, and a tracer emitting sufficiently hard gamma radiation is used. As sufficient mixing can be achieved by injecting upstream the separator the radiation level found will be strictly proportional to the concentration and thus inversely proportional to the true flow rate. 

Additives. Because of their versatility, imparted via chemical modification, the appHcations of ethyleneimine encompass the entire additive sector. The addition of PEI to PVC plastisols increases the adhesion of the coatings by selective adsorption at the substrate surface (410). PEI derivatives are also used as adhesion promoters in paper coating (411). The adducts formed from fatty alcohol epoxides and PEI are used as dispersants and emulsifiers (412). They are able to control the viscosity of dispersions, and thus faciHtate transport in pipe systems (413). Eatty acid derivatives of PEI are even able to control the viscosity of pigment dispersions (414). The high nitrogen content of PEIs has a flame-retardant effect. This property is used, in combination with phosphoms compounds, for providing wood panels (415), ceUulose (416), or polymer blends (417,418) with a flame-retardant finish. 

Reduced Emissions and Waste Minimization. Reducing harmful emissions and minimizing wastes within a process by inclusion of additional reaction and separation steps and catalyst modification may be substantially better than end-of-pipe cleanup or even simply improving maintenance, housekeeping, and process control practices. SO2 and NO reduction to their elemental products in fluid catalytic cracking units exemplifies the use of such a strategy (11). 

Before end-of-pipe wastewater treatment or modifications to existing wastewater treatment faciUties to meet new effluent criteria are undertaken, a program of waste minimisa tion should be initiated. 

Manufacturers offer flanged-end pipe in only a few metals. Otherwise, flanges are attached to pipe by various types of joints (Fig. 10-133). The lap joint involves a modification of the pipe which ma ... 

Environmental factors should also be incorporated into a company s technical or research and development program. Since the planning horizons for new projects may now extend to 5 to 10 years, R D programs can be designed for ecific projects. These may include new process modifications or end-of-pipe control technologies. 

Intent Plant personnel, supplies, and budget are reqiiired to successfully complete a unit test. Piping modifications, sample collection, altered operating conditions, and operation during the test require advance planning and scheduling. Analysts must ensure that these are accomplished prior to the actual test. Some or all of the following may be necessary for a successful unit test. 

Piping Modifications One resiilt of the inspec tion of the sample locations is a list of sample locations that will require modifications. The mechanical department will be required to make these modifications before the unit test is run. It is likely that the locations that are not typically used will be plugged with debris. The plugs will have to be drilled out before the test begins. Drilling out plugs presents a safety hazard, and those involved must be aware of this and follow the plant safety protocols. 

Comminution Shredding. A mechanical treatment process which cuts large pieces of waste into smaller pieces so that they won t plug pipes or damage equipment. Contact stabilization Contact stabilization is a modification of the conventional activated sludge process. In contact stabilization, two aeration tanks are used. One tank is for separate reaeration of the return sludge for at least four hours before it is permitted to flow into the other aeration tank to be mixed with the primary effluent requiring treatment. 

Inherently safer principles also apply to mechanical integrity requirements. Design plant modifications for ease and reduced risk in inspections, code compliance, and maintenance. For example, if one can check the pipe thickness from a platform, it is more likely to be done than if a crane is required. 

FEP, fault tree, gvent tree and piping instrumentation diagram (P ID) editor, accesses ihe package of graphical tools for risk assessment. These tools include the event tree, fault tree and P ID graphical editors. The event tree and fault tree editors are in PSAPACK the P ID editor is in FEP. The event tree editor is used for graphical construction and modification of event trees. The fault tree editor does the same for fault trees the P ID editor does the same for construction and modification of P IDs used in a PSA. 

One of the reactors developed a crack and had to be removed. (The crack was the result of a process modification see Section 2.6 b.) It was replaced by a temporary 20-in. pipe, which had two bends in it, to allow for the difference in height. The existing bellows were left in position at both ends of the temporary pipe (Figure 2-5). 

On chemical plants and oil refineries, steam, nitrogen, compressed air. lubricating oil, and other utility systems are responsible for a disproportionately large number of accidents. Flammable oils are recognized as a hazard, but services are given less attention. If the modification to the lubricating system had been systematically studied before it was made, as recommended in Chapter 2, a larger vent could have been installed, or a pipe-break and funnel could have been installed at the inlet to the sump. 

Maintaining flame arrester reliahility is critical to snccessfnl operation. Modifications to the system which may change gas composition shonld he care-fnlly evaluated to ensnre that the mixture with the lowest MESG is still within flame arrester certification. Other management of change issues include piping modificadons, increased or decreased pressures, and the introdnc-tion of corrosive, condensahle, or odier potentially harmfnl materials. 

A very delicate and useful piece of apparatus, which is leadily made with the blow-pipe, is Perkins modification of Sprengel s pyknometer. It is especially adapted for small quantities of liquid and for the moie volatile ones. The apparatus (Fig. 46) consists of a U l ube to hold from 2 to 10 c.c., drawm out at each end into a fine capillary. The one capillaiy limb, a, is bent outwards and is furnished with a small bulb the other, b, is bent at a right angle with the first. On the limb a, between the bulb and the top of the U-tnbe a mark is etched. The... 

The procedure recommended by Reference [18] is based on the conventional gas flow equations, writh some slight modifications. The importance in final line size determination is to determine w hat is a reasonable pressure loss at the absolute pressure required and the corresponding pipe size to balance these. In some cases a trial/error approach is necessary. 

The unit shown in Figure 4-49 has been used in many process applications with a variety of modifications [18,19,20]. It is effective in liquid entrainment separation, but is not recommended for solid particles due to the arrangement of the bottom and outlet. The flat bottom plate serves as a protection to the developing liquid surface below. This prevents re-entrainment. In place of the plate a vortex breaker type using vertical cross plates of 4-inch to 12-inch depth also is used, (Also see Reference [58].) The inlet gas connection is placed above the outlet dip pipe by maintaining dimension of only a few inches at point 4. In this type unit some liquid will creep up the walls as the inlet velocity increases. 

Modifications to give improved air and water flows, where these were shown to be deficient, i.e. increase fan speeds, change fans, change pumps, improve ductwork or piping to reduce pressure losses. 

HARTNETT and KOSTIC 26 have recently examined the published correlations for turbulent flow of shear-thinning power-law fluids in pipes and in non-circular ducts, and have concluded that, for smooth pipes, Dodge and Metzner S(27) modification of equation 3.11 (to which it reduces for Newtonian fluids) is the most satisfactory. 

Yooi24) has proposed a simple modification to the Blasius equation for turbulent flow in a pipe, which gives values of the friction factor accurate to within about 10 per cent. The friction factor is expressed in terms of the Metzner and Reed(I8) generalised Reynolds number ReMR and the power-law index n. 

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