Bleed-off

The precipitated copper from this reaction is an important constituent of the slime that collects at the bottom of the electrolytic cells. The accumulation of copper as well as of impurities such as nickel, arsenic, antimony, and bismuth is controlled by periodic bleed-off and treatment in the electrolyte purification section. 

Design of turbine blades to obtain higher effieieney and damping has been done. In some eases, this has improved effieieney by 8-10%, and stopped failures in these blades. Steam injeetion has been utilized in gas turbines to improve effieieney and to inerease the power output. Redesign of various bleed-off ports has redueed tip stalls and their aeeompanying blade failures. 

Metalized screens Screens that have been metalized with nickel. These screens will bleed off static charges, promote EMC and reflect electromagnetic energy. MGD Million gallons daily - refers to the flow through a waste treatment plant. 

Bleed off annulus piped to suction nozzle puts both stuffing boxes under suction pressure... 

Bleed-Off Line. This line bleeds off pressure within the standpipe, rotary base, kelly and the drill pipe to the depth of the top float valve. The bleed-off line allows air (or gas) under pressure to be fed directly to the blooey line. 

When cementing operation is completed, bleed off internal pressure inside the casing and leave valve open on cementing head. 

The amount of bleed-off required would depend on the nature of the make-up water and the type of conditioning chemicals used. The specialist tower manufacturer, conditioning chemical supplier or water-treatment consultant will advise the maximum concentration factor (the ratio of circulating water concentration to make-up water concentration) which can be allowed. The necessary bleed-off is then given by ... 

A simple manual valve running continuously to drain or by an automatic valve controlled by the conductivity of the circulating water may set the bleed-off. 

It is possible to remove all solids from the make-up water, but it is much cheaper to check the concentration by other means. Two general methods are employed. The first relies on physical or chemical effects to delay deposition of scale on the hot surfaces the second restricts the concentration to a level at which precipitation will not occur. In both cases, the accumulation of solids is removed by bleeding off water from the circuit to drain, in addition to that which is evaporated (see Figure 6.8). 

A tundish, having an area possibly 1% of the cross-sectional area of the tower, is located just above the water level and is led to the drain, forming part of the overflow fitting. This will bleed off 1 % of the water falling through the tower. 

All these methods provide the maximum required rate of bleed-off at all times of the year, and so will waste water at light load conditions. The user should be aware of the essential nature of bleed-off, since cases often occur in dry weather of misguided persons closing off the bleed to save water . 

In some locations, it is necessary to drain the tank frequently to clear other contaminants. With careful control, this can be used as the necessary bleed-off. 

Air washers require water treatment and bleed-off, since they concentrate salts in the tank. Steam will be free from such impurities, but the boiler will need attention to remove accumulations of hardness. 

Where water is evaporated from a circuit, such as a cooling tower, evaporative condenser, or humidifier, it must be remembered that there is no way of avoiding a steady bleed-off or frequent flushing, to restrict the concentration of dissolved solids. Much trouble arises from the efforts of well-wishing but misguided persons who stop the flow of bleed-off to save water . 

It is usually necessary to bleed off a portion of a recycle stream to prevent the build-up of unwanted material. For example, if a reactor feed contains inert components that are not... 

In some cases, as in the batchwise application of diazo components, it may be advisable to add electrolyte to the developing bath to inhibit bleed-off of low-substantivity naphthols. Otherwise the auxiliaries for batchwise and continuous application of diazo components are essentially the same. 

It is decided to bleed off 0.25 kg/s of vapour from the vapour line to the second effect for use in another process. If the feed is still heated to the boiling-point of the first effect by external means, what will be the change in the steam consumption of the evaporator unit ... 

Choose the Test Hydrant and record the date, time, and location of the test. Remove one of the hydrant outlet caps and attach a recently calibrated pressure gage fitted with a petcock valve. Slowly open the hydrant and bleed off any trapped through the petcock valve on the pressure gage cap, then close the... 

Insert the pitot flow measuring device into the hydrant water flow, bleed off air from the pitot tube, and then measure the pitot gage pressure. The pitot tip should be inserted in the center of the water flow stream at a distance of one-half diameter away from the outlet of the hydrant. 

Bleed off resin in the outlet port until no more gas bubbles can be seen there. 

If the velocity dependence of the rate of a reaction could be assumed to be constant and equal to k for velocities in excess of u0 and zero below 0, then reaction could be regarded as bleeding-off those reactant (Brownian) particles which have an energy in excess lmti02. This perturbs the velocity distribution of reactants and hence of solvent molecules [446]. Under such circumstances, the Fokker—Planck equation should be used to describe the chemical reaction. If this simple form of representing reaction is incorrect, there is little that can be done currently. The Fokker—Planck equation contains too much information about Brownian motion. In particular, the velocity dependence of the Brownian particles distribution is relatively unimportant. Davies [447] reduced the probability... 

In addition to the reactions that produce elemental sulfur, competing reactions also occur that produce undesirable by-products such as sodium thiosulfate. This is detrimental, because the thiosulfate remains in solution, and its concentration can generally be reduced only by bleeding off a portion of the solution inventory. This solution purge waste stream is hazardous, largely because it also contains vanadium compounds. The key to reducing the metal content of the waste stream is to reduce the rate of thiosulfate formation. 

Electrical charges play a strong role in stabilizing the oil-in-water emulsion. These charges can only be maintained in waters of low conductivity or low salt contest. As salt contest increases, this type emulsion becomes less stable since the charges on oil particles can bleed off and they can then more readily unite. With the emulsifying agent in the water, it tends to surround the oil particles and trap them. 

A three-bed adsorption unit is illustrated in Figure 15.16. It is used to dry the feed to a distillation column with a top temperature of —70°F thus a water dewpoint of —90°F is required. One of the vessels always is on regeneration and cooling down, and the other two in series on adsorption, with the more recently reactivated one downstream. A bleed off the process stream is diverted to use as regenerant. After the gas leaves the vessel being regenerated, the water is condensed out by cooling and the gas returns to the process downstream of a control valve that maintains a 10 psi differential. 

The inert atmosphere for the box may be supplied continuously with a bleed-off valve, or recirculated through purification trains that remove oxygen and water. Since all boxes leak to some extent (1 f/day is typical), recirculation through a purification train is desirable. Figure 19.1 shows a block diagram for a typical dry box with the recirculation option. Most trains can maintain oxygen and water to less than 1 ppm. If economics is a consideration, scientists can... 

Retention time is important as it affects the time a slug treatment will remain in the system. Lower bleed-off causes longer retention times. 

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