Tanks dosing

Figure 32.15 shows the radiation evolution in the surroundings of the permeate and feed tanks (points 4 and 5). Near the permeate tank (point 4), dose variation is not very significant since the permeate has a low activity level [10]. However, the radiation evolution near the feed tank (point 5) shows quite high dose values. This is because the liquid inside this tank has much higher activity than the hquid inside the permeate tank. Dose increase around the feed tank is due to progressive concentration of the liquid feed as a result of membrane concentrate recirculation to this tank [11]. 

Cooking extmders have been studied for the Uquefaction of starch, but the high temperature inactivation of the enzymes in the extmder demands doses 5—10 times higher than under conditions in a jet cooker (69). Eor example, continuous nonpressure cooking of wheat for the production of ethanol is carried out at 85°C in two continuous stirred tank reactors (CSTR) connected in series plug-fiow tube reactors may be included if only one CSTR is used (70). 

Chemical dosing. This is a connection into the tank with an internal diffuser for any corrective treatment required for the water. 

Most fish is still caught at sea and must be cooled soon after it is taken on board, and kept cold until it can be sold, frozen or otherwise processed [45]. The general practice is to put the fish into refrigerated sea water tanks, kept down to 0°C by direct expansion coils or a remote shell-and-tube evaporator. The sea water must be clean and maybe chlorine dosed. At this condition, fish can be kept for up to four days. 

Mr. Wondrich said that he got the idea for rye whiskey dosed with Tabasco sauce from a book of hard-luck stories, Tales of the Ex-Tanks, which purports to be the minutes of the Harlem Club of Former Alcoholic Degenerates, written by Clarence Louis Cullen, a New York Sun reporter, and published in 1900. 

Of course, improvements could be made to this simple program. The day tank could be heated to drive out most of the oxygen, or the chemical treatment could be added proportionally to the FW via a dosing/feed pump. As a result of the extremely low consumption, this last action most probably would require the added burden of using suitable quantities of dilution water to provide an acceptable degree of pump discharge accuracy. 

Traditionally, boiler house operational duties include the monitoring of day tank chemical treatment levels and the top-up of additional chemicals as required. Also required is the checking of consumable inventory stock levels and the inspection of chemical feed pumps, injection points, automatic controllers, and other items of dosing and control equipment. 

Ideally, the oxygen scavenger is added continuously rather than periodically shot-dosed where batch tanks are employed, there should not be more than one day s supply of oxygen scavenger in the tank. The tank contents should not be agitated any longer than necessary, to avoid aerating the mix. 

A means of adding liquid chemical treatment to a FW tank by means of an overhead dripping container rather than by use of a dosing pump. From a control viewpoint, drip feed is most usually unsatisfactory as the feed rate reduces over time with decrease in treatment head pressure, and ultimately the device tends to gum up. 

Influence of the mode of operation on process performance. The mode of operation of stirred-tank reactors can also significantly affect reactor performance. The history of concentrations will be changed by the time policy of reactant(s) addition to the reaction mixture. In view of our very limited possibility of controlling of temperature in stirred-tank reactors, the temperature-time dependencies for different policies of dosing will also be different. For example, the result of nitration depends upon the method of addition of nitric acid to aromatics, and the choice which phase is dispersed and which is continuous. Consequently, if the reaction is concentration- or temperature-sensitive the result will be dependent on the mode of operation (see Example 5.3.1.5). 

Cell link was dosed to Loop 1 water and after eight hours it was possible to detect residual HP in water going into the common filtrate tank. After two days residual HP was detected even in the water going into the pulper. 

In this example, we have a stirred-tank with a volume Vj of 4 m3 being operated with an inlet flow rate Q of 0.02 m3/s and which contains an inert species at a concentration Cm of 1 gmol/m3. To test the mixing behavior, we purposely turn the knob which doses in the tracer and jack up its concentration to 6 gmol/m3 (without increasing the total flow rate) for a duration of 10 s. The effect is a rectangular pulse input (Fig. 2.7). 

It should be realized also that either option shown in Fig. 9 or 10 will produce a non-symmetrical flow pattern inside the blow tank (i.e., due to preferential feeding at the blow tank outlet) and hence, promote the possibility of arching, rat holing and/or formation of dead regions. For these reasons, the combined fluidizing-discharge-cone and cone-dosing valve system shown in Fig. 8 is preferred. 

Tandem 7 nf bottom-discharge cone-dosing blow tanks, similar to those shown in Fig. 8, were employed for this purpose and also to regulate the feed of material into the pipeline and alleviate the occurrence of imminent blockages (Wypych, 1995b). 

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