Plastic tanks

The use of fixed plastic tanks is especially problematic for nonconductive flammable liquids because the efficiency of grounding aids (such as a conductive dip pipe or a submerged grounded metal plate) decreases as liquid 

Based directly on conclusions given in the Exxon study [207], API 2003 [3] recommends that the area of metal grounding plates should be not less 

---

Materials of Construction Suitable materials of constmction are steel, stainless steel, and aluminum 3003. Galvanized steel should not be used. Plastic tanks and lines are not recommended. 

Nonohmic behavior is pronounced for nonconductive liquids in plastic tanks, whose dielectric walls further complicate the charge decay rate [206]. 

Figure 8-66 RP (glass fiber-TS polyester plastic) tank trailers are used for hauling corrosive and hazardous materials. In Canada they meet code 312 to operate.

In South Africa, owing to the diversity and small production volume of specific motor car models, it is not economically feasible to blow-mold HDPE fuel tanks. The only cost-effective plastic tank manufacturing process used in South Africa is rotational molding, using LLDPE with a density of 0.939 g/cm3. Some selected properties of LLDPE before and after petrol exposure are compared to HDPE in Table 16.2. It is clear that owing to weaker mechanical properties, LLDPE is far less suitable than HDPE for petrol containment, mainly because of its lower crystallinity. 

Fiber glass-reinforced plastic tanks, 24 299 Fiber grating, 11 150-151 Fiber length (FL), 18 148 Fiber manufacture, sodium bisulfite in, 23 673 Fiber-matrix bonding, 26 771-772 Fiber modification, chemical, 16 14 Fibernodes, 11 595 Fiber-optic probes, 16 524 Fiber optics, 11 128-162, 15 469 attenuation in, 11 132-133 dispersion in, 11 134-135 fiber drawing in, 11 141-145 fiber strength in, 11 141-145 history of, 11 128-131 inside processes for, 11 136-140 near-infrared, 23 141 optical amplifiers with, 11 145-146 optical fiber fabrication for,... 

Mature, oocyte positive, female Xenopus laevis are kept in (mesh) covered grey plastic tanks in tap water (depth 15-20 cm, 3-4 L per animal) at 16-19°C under constant light regime (12-h day/night cycle). The quality of the tap water should be tested at the beginning and care should be taken on the chlorine and heavy metal content. A simple way to eliminate excessive chlorine from the water is storage of the water for 24 h. Clay tubes in the tanks allow the frogs to cover themselves. The animals are fed a commercially available pellet diet twice a week, and occasionally they receive small pieces of bovine heart. The tanks have to be cleaned after each meal. 

In cases where low intensity irradiation is needed batch treatment could be as simple as using a large-scale ultrasonic cleaning bath as the reaction vessel. However the tank would need to be constructed of a material which was inert towards the chemicals involved. An appropriate grade of stainless steel might prove adequate or plastic tanks could be used. In the latter case however the transducer would need to be bonded onto a stainless or titanium plate and this assembly then bolted to the tank. A useful variant to this and indeed one which offers greater flexibility in use is the sealed, submersible transducer assembly (Fig. 7.17). With either system some form of additional (mechanical) stirring would almost certainly be needed. 

No general rules-of-thumb are available for plastic tanks/containers failure criteria should be based on available test data (SINTER, 1997). FRP is used offshore for fire water lines in order to reduce weight. Wet pipe FRP systems may be effective in afire scenario because water is flowing, allowingthe heatto be carried away. If the pipe is dry, failure may rapidly occur. 

Cylindrical or rectangular bulk storage tanks, 2500-15000 liter capacity these are commonly fitted with delivery and ventilation pipes and an outlet pipe complete with a tap a few inches from the bottom. Although plastic tanks are sometimes used, those made with mild steel are more widespread. Clear marking of the tank is essential, and this is usually done with a label that cannot be altered and that is placed in a conspicuous area such as near the access opening. Safety and handling aspeets in a printed form should always be readily available, preferably in a plastic holder, secured to the tank. 

To help ensure resistance to impact and internal pressure increases, plastic tank wall thickness is greater than steel tank thickness. Plastic tanks are typically >4 mm in thickness, whereas steel tanks are somewhat less than 1 mm in thickness. Plastic tanks, however, are considerably lighter in weight. 

For reasons that will be explained in a subsequent chapter, the team found that the application of a technology known as bioflitration was considered the best remediation method. The contaminated gas is pumped through a column packed with a material that performs two functions (1) it provides for efficient contact between the air passing through it and water, and (2) it serves as a scaffold for the development of a bacterial colony. Figure 1.7 shows a typical biofiltration arrangement. The team must develop a system that has a very low pressure drop so that the process can be constructed from plastic tanks and low-pressure pumps to save money. In a further effort to save money, the process should have a small footprint. 

Epoxies show superior adhesion to metals and glass, and have limited shrinkage during cure. They are used for surface coatings, as adhesives and rc>r laminating to produce plastic tanks, pipe, and aircraft parts, etc (Ref 3, p 445-R). They also have been used in manuf of plastics (Ref 1), construction of rockets St missiles (Ref 2) and in manuf of explosive compositions of improved mechanical and thermal stability (Ref 4)... 

Lees, P., McAllister, D., Smith, J.R., Britton, L.G., and Hughes, J.F., An experimental and computational investigation of electrostatic fields in plastic tanks during filling with low conductivity fuel, J. Electrostatics, 10, 267-273, 1981. 

Bustin, W.M., Static Electricity Precautions for Plastic Tank Truck Compartments, Exxon Engineering Technical Report EE.56E.84, July 1984. 

---