Transportation static electricity

Pratt, T. H., Static Electricity in Pneumadc Transport Systems, Process Safety Progress, V. 13, No. 3, 1994, p. 109. 

Sparks due to static electricity associated with the separation of two dissimilar materials (Table 5.5). The charges may be transported/conducted some distance after separation before there is sufficient accumulation to produce a spark, e.g. in the flow of liquids or... 

The worst hazard scenarios (excessive temperature and pressure rise accompanied by emission of toxic substances) must be worked out based upon calorimetric measurements (e.g. means to reduce hazards by using the inherent safety concept or Differential Scanning Calorimetry, DSC) and protection measures must be considered. If handling hazardous materials is considered too risky, procedures for generation of the hazardous reactants in situ in the reactor might be developed. Micro-reactor technology could also be an option. Completeness of the data on flammability, explosivity, (auto)ignition, static electricity, safe levels of exposure, environmental protection, transportation, etc. must be checked. Incompatibility of materials to be treated in a plant must be determined. 

The ability of fuel to conduct electrical charge is of benefit during pipeline transport and during high-velocity loading and off-loading operations. Fuel movement in pipelines and transfer lines creates a static electrical charge. If polar compounds... 

DuPont 8c Co, M Blasters Handbook(1966), 169—74 Hazards of Extraneous Electricity which includes on pp 170—71, " Static Electricity". The Pamphlet of the Institute of Makers of Explosives, entitled "Radio Frequency Energy — A Potential Hazard in the Use and Transportation of Electric Blasting Caps is obtainable thru the DuPont Co... 

Common sources of low-level exposure to electromagnetic fields are electric and magnetic powered transport (static fields), overhead power lines, domestic electric appliances (ELF), antitheft electronic devices, or video display units (in very low to low... 

It is thus clear that neither orientational defects nor ion states can by themselves account for static electrical conductivity. Instead equal currents, measured in terms of the number of defects transported, must be carried by each mechanism so as to maintain the polarization of the ice structure at its equilibrium value. When both an orientational defect and an ion state move through the crystal in this way, leaving it in its original state, the total charge transported is that of a single proton, e. Thus the effective charges + of orientational defects and + of ion states are related by... 

In the process industry there are numerous procedmes by which badly conducting materials enter into mutual contact. Processes in which gas-solid mixtures or dusts are used or pneumatic transport should be mentioned in this context. Hence, the following areas where static electricity is to be expected are identified ... 

Electrostatic interactions in air are very different compared to the electrostatic interactions in aqueous systems, as there is no ion solubility and no double layer is formed. The source of the surface charges is also different. In air, there are no possibilities for acid-base interactions or for ion disassociation. Charging in air is caused by static electricity and is stable for non-conducting particles. This makes the interaction coulombic in nature, with a range comparable to the radius of the particle. The electrostatic interactions easily dominate when the particle size is large, the density is low, and there is a low water content (low conductivity). Typical examples could be during the drying of milk powder or the transport of coffee powder. 

Namely, poly(ethylene) and poly(vinyl chloride) films tend to hold high static electrical charge. This static charge is generated when the substrates unwind from the spool or are transported via a conveyor system under the printer nozzle. The static charge can be up to 40 kV. This charge tends to distort the ink droplets, causing the droplets to break up more easily and form microsatellites. These microsateUites then accumulate on the printer nozzle. 

Static electricity is generated where there is relative motion and/or separation of two dissimilar materials. The charge can be transported or conducted some distance before it becomes great enough to cause a discharge which provides the source of ignition. The best means of control is... 

Loading is one of the most hazardous operations in the process industries. These facilities represent a strategic point in the process that, if lost, may adversely affect the entire operation of the facility. Pipeline transport is the preferred method of material transport but cannot be accommodated in instances where smaller quantities are involved or where trans-ocean shipment is required. The most prevalent hazard with loading facihties is the possibility of overfilling, displacement and release of combustible vapors, buildup of static electricity, and collisions with transferring facilities and carrying vehicle (primarily ships, barges, or trucks). 

Many incidents occur during the transportation of people and freight. This chapter discusses some of the special safety issues to do with this topic. Also discussed here is the control of static electricity when loading and unloading liquids to and from tank trucks and railcars. 

The fabric may also be given one or more of a number of other finishing treatments, either ia tandem with web formation and bonding or off-line as a separate operation, as a means of enhancing fabric performance or aesthetic properties. Performance properties iaclude functional characteristics such as moisture transport, absorbency, or repeUency flame retardancy electrical conductivity or static propensity abrasion resistance and frictional behavior. Aesthetic properties iaclude appearance, surface texture, and smell. 

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