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Glossary Of Terms For Chemical Processing Applications:

Alkali Metals – any of the metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium. NaK, or sodium-potassium alloy, is also considered an alkali metal because it is a mixture of two alkali metals, sodium and potassium). All alkali metals are very reactive with air and water. The water reaction is vigorous to explosive and produces hydrogen gas and hydroxides. The hydroxides of the alkali metals are strongly alkaline.

Automation – the technique of making an apparatus, a process or a system operate automatically, generally meaning without a person being required to initiate each action.

Dispersion – a mixture in which a solid or liquid is broken up into small particles and evenly distributed in a base liquid. Process engineers and chemists use dispersions to increase the surface area and there-by the reactivity of various chemicals. There are many products which are dispersions and several types of equipment can be used to product dispersion. Paint is a common dispersion.

Electromagnetic Pumps – type of pump using magnetic fields and electric current to generate a flow in liquid metals. EM Pumps (as they are known) have the advantage of no moving parts and no seals to leak. They do require that the fluid being pumped be conductive. AC and DC electro magnetic pumps are available. Both conduction and induction styles of electro magnetic pumps are possible. These pumps are very specialized devises used most commonly for alkali metals. See the brochure for CEI’s line of electromagnetic pumps by clicking here.

Etching – the process of removing a small amount of material from its surface using a chemical or acid etchant. Etching is generally performed to increase the ability of an adhesive or coating to bond to the material’s surface.

Fluoropolymer Etching – the process of removing fluorine ions from the surface of a fluoropolymer to enable a bond to the etched surface of the fluoropolymer. Etching is usually required to adhere fluoropolymers to other materials or to color just the surface.

Lithium – a soft silver colored metal of the alkali metal group, lithium is the lightest of the alkali metals, and is reactive with both water and air and can form shock sensitive compounds on exposure to air. Lithium is used mostly in the nuclear and battery industries.

Process Engineering – the design of a series of unit operations, actions, or activities that produce a desired product or end result. The principal communication tools of process engineers are PFDs (Process Flow Diagrams) and P&IDs (A diagram which shows the interconnection of process equipment and the instrumentation used to control the process. In the process industry, a standard set of symbols is used to prepare drawings of processes. The instrument symbols used in these drawings are generally based on Instrument Society of America (ISA) Standard S5. 1.).

Project Engineering – the integration of existing equipment and knowledge to bring together the physical assets necessary to produce a product or other end result. A typical output from project engineering might be equipment or system fabrication drawings, assembly drawings, piping drawings and related specifications.

Potassium – refer to the definition of sodium, potassium is similar to sodium but is more reactive than sodium with both oxygen and water. Potassium is used less than sodium in chemical processing because of its higher cost. For the physical properties of potassium click here. Potassium on exposure to air or oxygen can form a superoxide which can be used as a chemical oxygen source for respirators but which also can present a shock sensitive hazard in the presence of elemental potassium and an organic compound.

Skid Systems – an assemblage of process equipment including piping and electrical controls designed to accomplish a given task that is self contained and moveable. This may include very small process units which are moved by hand, pushed on wheels or moved with heavy construction equipment. Large skid systems may be bolted together one on a job site and are no longer moveable. Skid mounted systems are general shop fabricated for lower cost and safety reasons versus field constructed units. Skid Systems are also less disruptive of on-going operations.

Sodium – a soft, silver colored element in the alkali metal group, the metal is very reactive and forms a white oxide on exposure to air, reaction with water is rapid and can be violent. Sodium requires special process engineering techniques to use safely in elemental form, for physical properties of sodium, click here. Sodium is a common reactant in chemical processing.

Sodium Potassium Alloy / NaK – a mixture of elemental potassium and elemental sodium, NaK has unique properties such as remaining liquid down to 9 º F at the eutectic mixture (78 wt% potassium, 22 wt% sodium). Used principally for its catalytic effect and easy of handling in the liquid form, NaK is a key material in producing IBB (isobutyl benzene), a necessary ingredient in the manufcture of ibuprofen. NaK’s unique properties require specific process engineering knowledge to handle safely.

Sodium Dispersion – a mixture of very small particules of solid sodium suspended in a carrier fluid. Sodium dispersions are used to produce a range of products and the dechlorinate PCBs. Because the sodium is finely divided, it is very reactive which is an advantage but care must be taken when handling sodium dispersions, particularly at elevated tempertures.

Superheated Steam Process – a technique for safely reacting unwanted alkali metals for disposal or reclamation of the hydroxide. The steam is a much less concentrated form of water which allows it to be applied less locally and in easily measureable dilute quantities when delivered with inert gas. Typically, the steam is superheated to minimize condensate droplets fed to the alkali metal bearing system. The alkali metal bearing system is maintained oxygen free during the reaction period to ensure that an explosion cannot take place.

Water Vapor Nitrogen / WVN Process – a technique for reacting alkali metal residues with water vapor. An inert gas stream is humidified by bubbling the gas stream through a water bath which is maintained at a controlled temperature (near ambient) and then introduced into the alkali metal bearing sytem to react the alkali metal to form hydrogen gas and the corresponding hydroxide. The water vapor nitrogen process introduces moisture at much lower rates than does the superheated steam process.

“Wetting” – A phenomenom usually used to describe the adherence of liquid alkali metal to the wall of a pipe in such a way as to form and hold a film on the pipe wall. Wetting of the wall is essential for heat transfer, and for pumping and flow measurement using electromagnetic pumps and flowmeters. As a general rule the alkali metal and pipe surface must be heated to approximately 600°F for a minimum of one hour to “wet” the pipe.

“Weathering” – a process for reacting alkali metals to hydroxides involving exposure to air. The process works for very small quantities but attention must be paid to liquid accumulation which can lead to unexpected “pops and bangs”.

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