Heating with tank coils

The caliche is worked for refined nitrate on the places of production in about one hundred and fifty factories. The ground is broken by blasting, and the big blocks are broken into smaller ones by means of crowbars, and the lumps of caliche are separated from the rocky over-layer by hand. The caliche is crushed into 2-in. lumps, placed in long iron tanks heated with steam coils, and is there boiled with water. The earthy residue is left on a false bottom about 1 ft. from the real bottom of the tank, while the mother liquors, containing the NaNOs in solution, are run into the next tank. The extraction of the caliche is carried out systematically. The tank containing nearly exhausted caliche is treated with fresh water, while the liquor from this tank is run through a 9-in. pipe into the second tank, where it meets with a partly extracted caliche. From this, still... 

Shipment and Storage. 2-Pyrrohdinone is available in steel dmms and in aluminum or stainless-steel tank cars and tank trailers. Because of its high freezing point, bulk shipments are in tanks with heating coils. Heating with hot water rather than steam avoids product discoloration. Steel (qv), stainless steel, and aluminum are satisfactory materials for storage containers. Because 2-pyrrohdinone is hygroscopic, it must be protected from atmospheric moisture. 

External Coils and Tracers Tanks, vessels, and pipe hnes can be equipped for heating or cooling purposes with external coils. These are generally 9.8 to 19 mm (% to V4 in) so as to provide good distribution over the surface and are often of soft copper or aluminum, which can be bent by hand to the contour of the tank or hne. When necessary to avoid hot spots, the tracer is so mounted that it does not touch the tank. 

Storage tanks can be heated with thermostatically controlled steam coils, hot-water coils, electric immersion heaters or a combination of these. The elements and their... 

The temperature of the acid for the production of this nitrocellulose should be 20-30°C, while in the production of lower nitrated guncotton (CP2) a temperature of 25-33°C is permitted. The acid is maintained at the required temperature in special tanks (temperature stabilizers) situated above the metering tanks. The stabilizers are heated with warm water or cooled with cold water, usually by means of a coil. 

The mixed acid was warmed to the required temperature (30°C at Kriimmel and 18°C at Aschau) by means of temperature stabilizers. These were cylindrical tanks provided with a coil to heat or to cool the content, and a mechanical stirrer. 

Effective wastewater management in this phase of veneer and plywood production can be accomplished in part by in-plant operational changes and in part by equipment modification. For plants with hot water vats that are heated indirectly with steam coils, the discharge results from spills in loading and unloading the vat and from periodic cleaning. Plants operating in this manner need only to collect the water in small ponds or tanks and reuse it for vat makeup water. Adjustments in pH by the addition of lime or caustic soda may be required to control acidity and prevent the development of corrosion problems. 

Due to the difference of pressures in the appratuses raw trichlorfon continuously flows out of the ager into the system where secondary unreacted products are distilled. First, raw trichlorfon is heated to 80 °C in heater 5 by sending hot water into the space between the pipes. Then, the mixture leaves the heater and enters distillation tower 6, filled with Raschig rings and fashioned with a coil with hot water. Distillation is conducted at 80-90°C and a residual pressure of 26-27 GPa. The distilled unreacted products (mostly chloral) flow through cooler 7 into collector 8 and are loaded into the distillation tank as they accumulate. There chloral is distilled over sulfuric acid, and the ready product, trichlorfon, continuously flows from tower 6 into collector 9. It is heated with 40 °C water (through the jacket). 

The first step in the manufacture of TNT is the the nitration. This reaction is carried out in a large vessel called the nitrator. This nitrator is generally a cylindrical kettle or tank, built of either an acid-proof cast metal or of boiler plate. The material of which the nitrator is built should be thoroughly tested with the acids of various concentrations met with in the manufacture of the product. The nitrator must be well equipped with cooling coils and heating coils so placed that the temperature of the reacting mixture... 

Finished-product storage tanks are usually closed and fitted with tank tops, internal heating or cooling coils, and an agitator to promote heat transfer and to prevent localized overheating. A typical finished-product storage is depicted in Figure 12. 

The four 30,000-gal stainless steel tanks are buried in a horizontal position. They are 12 ft in diameter and have a 38-ft-long straight side. The shell and head of these tanks are 11/16 and 9/16 in. thick, respectively. They also are equipped with cooling coils and are connected to a shell-and-tube condenser to remove heat produced by the decay of radionuclides. These tanks rest on a concrete pad but are not surrounded by a vault. A curb surrounds the concrete pad, and a sump equipped with a level alarm collects any leakage from the tanks. A 24-in.-diameter pipe extends from the surface of the ground to the sump so that a portable unit can be used to empty the sump if necessary. 

Nomenclatore A = area A, = area of tank bottom = area of coil Ag = equivalent area Ag = area of sides At = area of top Ai = equivalent area receiving heat from external coils A2 = equivalent area not covered with external coils Df = diameter of tank F = design (safety) factor h = film coefficient ha = coefficient of ambient air he = coefficient of coil hh = coefficient of heating medium hi = coefficient of liquid phase of tank contents or tube-side coefficient referred to... 

The same presentation as in equation (7.17) was also chosen by Frobese and Bohnet [146] for the heat transfer characteristic of a propeller stirrer in a tank with H/D — 1, which was equipped with meander coils for cooling. They found for the Re range Jie = 1 x 10 -2 x 10 the analytical expression ... 

Frobese and Bohnet [146] investigated the heat transfer in a tank with a high aspect ratio (H/D = 3), which was equipped with meander coils for cooling and three 3-waned stirrers on the same shaft. They used glass beads as solid particles with dp = 68-294 pm. They found for > 0.1 a different process equation than for... 

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