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In direct steam distillation, the starting material is suspended above the water in the boiling flask, supported by a metal mesh or perforated screen. In dry steam distillation , the steam from a boiler is forced to flow through the starting material in a separate container.
If using a vacuum pump, the vapor produced by sublimation is removed from the system by converting it into ice in a condenser, operating at very low temperatures, outside the freeze drying chamber. Supercritical drying (superheated steam drying) involves steam drying of products containing water. This process is feasible because water in the ...
Dry distillation is the heating of solid materials to produce gaseous products (which may condense into liquids or solids). The method may involve pyrolysis or thermolysis, or it may not (for instance, a simple mixture of ice and glass could be separated without breaking any chemical bonds, but organic matter contains a greater diversity of molecules, some of which are likely to break).
Both flasks are submerged in a dry ice/acetone cooling bath (−78 °C) the temperature of which is being monitored by a thermocouple (the wire on the left). A cooling bath or ice bath , in laboratory chemistry practice, is a liquid mixture which is used to maintain low temperatures, typically between 13 °C and −196 °C.
Frequently, steam, air, inert gases, and hydrocarbon gases are used as stripping agents. This is based on solubility, stability, degree of corrosiveness, cost, and availability. As stripping agents are gases, operation at nearly the highest temperature and lowest pressure that will maintain the components and not vaporize the liquid feed stream ...
Methane pyrolysis, the direct conversion of methane to hydrogen fuel and separable solid carbon, sometimes using molten metal catalysts. Hydrous pyrolysis, in the presence of superheated water or steam, producing hydrogen and substantial atmospheric carbon dioxide. Dry distillation, as in the original production of sulfuric acid from sulfates.
The Mollier enthalpy–entropy diagram for water and steam. The "dryness fraction", x , gives the fraction by mass of gaseous water in the wet region, the remainder being droplets of liquid. An enthalpy–entropy chart , also known as the H – S chart or Mollier diagram , plots the total heat against entropy, [ 1 ] describing the enthalpy of a ...
Where Q d is the steam quantity at ejector delivery, Q s at ejector suction and Q m is the motive steam quantity. For this reason, a thermocompression evaporator often features a vapor condenser , due to the possible excess of steam necessary for the compression if compared with the steam required to evaporate the solution.