Acid meters

The arrangements for introducing measured quantities of acid and glycerine are connected by a lever (2) in such a way that the influx of acid and nitroglycerine into the nitrator proceeds at a pre-determined ratio. Movement of the tipping vessel exerts a pull on the lever and this takes the brakes off the bucket conveyer. At once the conveyer starts to move and continues to do so until the acid metering vessel returns the lever to its former position and stops the conveyer again. 

Use metering pumps instead of centrifugal pumps since the latter can feed in excessive amounts of reactants, fuel oils, and acids. Metering pump is more suitable for controlled feeding. 

Input acid composition Speed of sound through acid meter (Weerstra, 2012) Adjust dilution water input rate... 

A pH electrode is normally standardized using two buffers one near a pH of 7 and one that is more acidic or basic depending on the sample s expected pH. The pH electrode is immersed in the first buffer, and the standardize or calibrate control is adjusted until the meter reads the correct pH. The electrode is placed in the second buffer, and the slope or temperature control is adjusted to the-buffer s pH. Some pH meters are equipped with a temperature compensation feature, allowing the pH meter to correct the measured pH for any change in temperature. In this case a thermistor is placed in the sample and connected to the pH meter. The temperature control is set to the solution s temperature, and the pH meter is calibrated using the calibrate and slope controls. If a change in the sample s temperature is indicated by the thermistor, the pH meter adjusts the slope of the calibration based on an assumed Nerstian response of 2.303RT/F. 

Polymerization. The polymerization of aziridines takes place ia the presence of catalytic amounts of acid at elevated temperatures. The molecular weight can be controlled by the monomer—catalyst ratio, the addition of amines as stoppers, or the use of bifimctional initiators. In order to prevent a vigorous reaction, the heat Hberated during the highly exothermic polymerization must be removed by various measures, ie, suitable dilution, controlled metering of the aziridine component, or external cooling after the reaction has started. 

The appearance of streaks with leveling or nonleveling acid and premetallized dye can be subdued by increasing the dye-bath pH from 5.5 to 6—7, at a sacrifice ia dye exhaust, by a dding chemical agents that retard the dye strike or, more effectively, by metering all or a portion of the dye ia a concentrated solution at or near the dyeiag temperature of the fiber (87.8—104.4°C) iastead of at the usual 26.7—48.9°C practiced by the trade (178). 

After the SO converter has stabilized, the 6—7% SO gas stream can be further diluted with dry air, I, to provide the SO reaction gas at a prescribed concentration, ca 4 vol % for LAB sulfonation and ca 2.5% for alcohol ethoxylate sulfation. The molten sulfur is accurately measured and controlled by mass flow meters. The organic feedstock is also accurately controlled by mass flow meters and a variable speed-driven gear pump. The high velocity SO reaction gas and organic feedstock are introduced into the top of the sulfonation reactor,, in cocurrent downward flow where the reaction product and gas are separated in a cyclone separator, K, then pumped to a cooler, L, and circulated back into a quench cooling reservoir at the base of the reactor, unique to Chemithon concentric reactor systems. The gas stream from the cyclone separator, M, is sent to an electrostatic precipitator (ESP), N, which removes entrained acidic organics, and then sent to the packed tower, H, where SO2 and any SO traces are adsorbed in a dilute NaOH solution and finally vented, O. Even a 99% conversion of SO2 to SO contributes ca 500 ppm SO2 to the effluent gas. 

FIG. 15-38 Extraction rates for sieve-plate and modified biihhle-plate columns. System benzoic acid-water-toliiene, except where noted. To convert feet to meters, multiply by 0.3048 to convert inches to centimeters, multiply by 2.54. [Alletion, Strom, and Treyhal, Trans. Am. Inst. Cbem. Eng., 39, 361 (1943) Row, Kojfolt, and Withrow, ihid., 37, 559 (1941) Treyhal and Dumoulin, Ind. Eng. Cbem., 34, 709(1942).]... 

FIG. 15-42 Extraction in Mixco columns, methyl isobutyl ketone-acetic acid-water (continuous), d, = 0.5 ft, Zj = 0..3.3.3 ft, X = flooded condition. To convert feet to meters, multiply by 0..34S to convert feet per hour to meters per hour, multiply by 0.3048. 

The tilkalinity and acidity is generally controlled, based on the timounts itnd also by maintaining the pH vtilue of the effluent discharge between. 1.5. and 9,0. the ideal being tirotind 7.5. as far tis possible. The pH can be checked w ith the help of a pH meter. 

In those days, there were no oil refineries, nor bottlers of carbonated soda, nor sulfuric acid plants. There was only one liquid to consider, and move in large quantities. .. fresh water from the mountains. With only one liquid under consideration, fresh water, and no. sophisticated instrumentation, they measured the water s force, or pressure, in terms of elevation. It is for this reason that today all over the world, pump manufacturers u.se the term Head measured in meters or feet of elevation to express pre.ssure or force. The term flow expresses volume over time, such as gallons per minute, or cubic meters per second. 

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