Steam jackets

Maintenance of isothermal conditions requires special care. Temperature differences should be minimised and heat-transfer coefficients and surface areas maximized. Electric heaters, steam jackets, or molten salt baths are often used for such purposes. Separate heating or cooling circuits and controls are used with inlet and oudet lines to minimize end effects. Pressure or thermal transients can result in longer Hved transients in the individual catalyst pellets, because concentration and temperature gradients within catalyst pores adjust slowly. 

In any procedure involving the handling of molten sulfur, the lines and spray nozzles must be steam-jacketed, and steam pressure must hold the molten sulfur within the range of 135—155°C, where its viscosity is at a minimum. Above 160°C, the viscosity rises sharply, and at 190°C its viscosity is 13,000 times that at 150°C. 

Batch distillation (see Fig. 3) typically is used for small amounts of solvent wastes that are concentrated and consist of very volatile components that are easily separated from the nonvolatile fraction. Batch distillation is amenable to small quantities of spent solvents which allows these wastes to be recovered onsite. With batch distillation, the waste is placed in the unit and volatile components are vaporized by applying heat through a steam jacket or boiler. The vapor stream is collected overhead, cooled, and condensed. As the waste s more volatile, high vapor pressure components are driven off, the boiling point temperature of the remaining material increases. Less volatile components begin to vaporize and once their concentration in the overhead vapors becomes excessive, the batch process is terrninated. Alternatively, the process can be terrninated when the boiling point temperature reaches a certain level. The residual materials that are not vaporized are called still bottoms. 

Handling saturated brines that require elevated temperatures the tank may be steam jacketed. 

O When scale formation due to flash evaporation is a problem or filtrate temperature must be maintained a vacuum box steam jacketing may be provided. 

Dampf-heizrohr, n. steam (heating) pipe, -heizung, /. steam heating, -holzschliff, m. steamed mechanical wood pulp, -hiillet /. steam jacket vaporous envelope. 

For steam jacketed, agitated closed reactor ketdes, the overall U usually will range from 40-60 Btu/hr (ft ) ( F). Of course, the significant variables are the degree or type of internal wall turbulence and the viscosity and thermal characteristics of the internal fluid. For water or other liquid cooling in the reactor jacket, the U value usually ranges from 20-30. 

Steam Jacketed kettle Paraffin wax None Copper 27.4 Product ... 

Steam Jacketed kettle Boiling water None Steel 187 Product ... 

The diverse types of plant in this category would be too numerous to list, but include steam-jacketed pans, steam calorifiers, steam heating and drying units and all types of air-pressure vessels. These are manufactured in a wide range of materials (e.g. stainless steel) and may then be lined with materials such as mbber or glass, depending on the needs of the process in which the vessel will be used. 

Fine chemicals There are many applications of the austenitic steels in the manufacture and storage of fine chemicals and pharmaceutical products. These include storage tanks, pipelines, valves, stills, steam-jacketed pans, mixing vessels, filters and tableting machinery. Considerable use has been made of these steels in penicillin production. 

Medium containing up to 35% glucose is steam sterilised by a steam jacket around a conventional stirred tank reactor. pH adjustment starts as the medium cools and is maintained at 65. Vigorous aeration is again required. Inoculation is usually by using a mycelial suspension. Under these conditions a 30% glucose solution can be almost quantitatively converted to sodium gluconate within 36 hours. 

M.B. Powder (Modified Black Powder). Consisted of BkPdr in which part of the K nitrate was replaced by K perchlorate. The finely pulverized ingredients were preliminarily mixed, as in the prepn of BkPdr, and then incorporated together in a steam jacketed pan. The last operation was dangerous and some fires occurred, which were ascribed to friction in the hot, dry caked material. A similar expl was called Roslin Giant Powder Ref Marshall 1,385 (1917)... 

PTX-1. An expl developed at PicArsn during WWII for use in land mines and demolition charges. It contained Tetryl 50, RDX 30 and TNT 20% mw 252 OB to CO -9%, to C02 —45% mp, eutectic 67°, pouring temp 90—95° d (cast) 1.68g/cc exudes at 65° and above sol in acet. Prepd by adding the appropriate wt of w-wet RDX to 40/60 Tetrytol previously melted in a steam-jacketed melt kettle. Heating and stirring are continued until all the w is evapd and the mixt is uniform in compn. It can also be prepd by adding Tetryl to Composition B Blast. Relative to TNT in air impulse 109%,... 

PTX-2 can be prepd by adding the appropriate wt of w-wet RDX to 30/70 Pentolite previously melted in a steam-jacketed melt kettle. Heating and stirring are continued until all the w is evapd and the mixt is uniform in compn. It can also be prepd by adding w-wet PETN to Composition B... 

About 75 ml. of ethanol is used for every gram of butenolide to be dissolved. Clarification of the solution with charcoal should be avoided because the butenolide tends to separate from solution during filtration and clogs the steam-jacketed funnel. The crystallized butenolide melts at 150-152°. 

Figure 3.6. Implicit loop calculation of the steam jacket dynamics.

PERIOD = 1 is the heating period using a steam mass flow rate of Fs. The mass balance on the steam jacket determines the steam density ps, which together with a steam table function determines the temperature of the jacket Tj. 

When an ophthalmic ointment is manufactured, all raw material components must be rendered sterile before compounding unless the ointment contains an aqueous fraction that can be sterilized by heat, filtration, or ionizing radiation. The ointment base is sterilized by heat and appropriately filtered while molten to remove extraneous foreign particulate matter. It is then placed into a sterile steam-jacketed kettle to maintain the ointment in a molten state under aseptic conditions, and the previously sterilized active ingredients) and excipients are added aseptically. While still molten, the entire ointment may be passed through a previously sterilized colloid mill for adequate dispersion of the insoluble components. 

The reactor wall is constructed of a steam jacket to protect the steel from high temperatures. The slag produced is mainly leaving the reactor through a bottom hole. 

A reaction flask was equipped with stirrer, thermometer, dropping funnel, and a steam-jacketed condenser that would allow ethyl... 

Vessel steam jackets are often rated for low-pressure steam. Reliefs are installed in jackets to prevent excessive steam pressures due to operator error or regulator failure. 

While the Dove composition described in Table 9.4-2 was processable at reasonable line speeds on a conventional soap processing line (roll mills, extruders, stampers), some equipment modifications were necessary. For example, whereas soap is normally mixed in large agitated tanks, the Dove mixture had a much greater viscosity and therefore required use of a steam-jacketed kneader mixer such as those used to make bread dough, pastes or mastics. 

Continuous freeze-drying equipment has been developed(60), and chopped meat and vegetables may be dried in a rotating steam-jacketed tube enclosed in the vacuum chamber. A model of the freeze-drying process has been presented by Dyer and Sunderland191 , and further details are given in Section 15.8 on freeze crystallisation. 

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