Materials storage tanks

Note The isopentane feed valve is designed to fail closed on a power failure to prevent reverse flow from the kettles to the raw material storage tanks. This is the appropriate failure position for this valve. 

Passive for example, safety features that do not require action by any device - they perform their intended function simply because they exist for example, a blast resistant concrete bunker for an explosives plant, or a containment dike around a hazardous material storage tank. 

Fig. 4.7. NF devices. 1. Raw material storage tank 2. Infusion pump 3. Circulating valve 4. Concentration valve 5. Flowmeter valve 6. Membrane components 7. Gauge 8. Flowmeter 9. Penetrant storage tank [12].

Every facility can benefit from a review of its infrastructure. This includes all utilities, entrances/exits, process and production equipment, telephone and data lines, water supply, backup power systans, process controls, hazardous material storage tanks and pits, fire alarm systems, and sprinkler systems. Making a list of all infrastructure details is helpful when evaluating security vulnerability, as well as such mundane tasks as budget analysis, routine and preventive maintenance, and personnel responsibilities. 

The 163-N facility contains demineralization equipment, including ion exchange units, regeneration tanks, treatment tanks (for pH adjustment) that are part of the elementary neutralization unit (ENU), acid and caustic-materials storage tanks, a heater, and a degasifier (DOE-RL 1990). 

Asphaltic materials storage tanks, tank cars, hnes. packages ... 

Clearly, the time chart shown in Fig. 4.14 indicates that individual items of equipment have a poor utilization i.e., they are in use for only a small fraction of the batch cycle time. To improve the equipment utilization, overlap batches as shown in the time-event chart in Fig. 4.15. Here, more than one batch, at difierent processing stages, resides in the process at any given time. Clearly, it is not possible to recycle directly from the separators to the reactor, since the reactor is fed at a time different from that at which the separation is carried out. A storage tank is needed to hold the recycle material. This material is then used to provide part of the feed for the next batch. The final flowsheet for batch operation is shown in Fig. 4.16. Equipment utilization might be improved further by various methods which are considered in Chap. 8 when economic tradeoffs are discussed. 

Solids materials that are insoluble in hydrocarbon or water can be entrained in the crude. These are called bottom sediments and comprise fine particles of sand, drilling mud, rock such as feldspar and gypsum, metals in the form of minerals or in their free state such as iron, copper, lead, nickel, and vanadium. The latter can come from pipeline erosion, storage tanks, valves and piping systems, etc. whatever comes in contact with the crude oil. 

Johnston D Aboveground storage tank floor inspection using magnetic flux leakage Material Perform t.31 no 10 1990 p.36-39. 

The reactor effluent, containing 1—2% hydrazine, ammonia, sodium chloride, and water, is preheated and sent to the ammonia recovery system, which consists of two columns. In the first column, ammonia goes overhead under pressure and recycles to the anhydrous ammonia storage tank. In the second column, some water and final traces of ammonia are removed overhead. The bottoms from this column, consisting of water, sodium chloride, and hydrazine, are sent to an evaporating crystallizer where sodium chloride (and the slight excess of sodium hydroxide) is removed from the system as a soHd. Vapors from the crystallizer flow to the hydrate column where water is removed overhead. The bottom stream from this column is close to the hydrazine—water azeotrope composition. Standard materials of constmction may be used for handling chlorine, caustic, and sodium hypochlorite. For all surfaces in contact with hydrazine, however, the preferred material of constmction is 304 L stainless steel. 

Plastics and Elastomers. Common plastics and elastomers (qv) show exceUent resistance to hydrochloric acid within the temperature limits of the materials. Soft natural mbber compounds have been used for many years as liners for concentrated hydrochloric acid storage tanks up to a temperature of 60°C (see Rubber, natural). SemUiard mbber is used as linings in pipe and equipment at temperatures up to 70°C and hard mbber is used for pipes up to 50°C and pressures up to 345 kPa (50 psig). When contaminants are present, synthetic elastomers such as neoprene, nitrile, butyl. 

For off-site transportation, the phosphoms is loaded into railcars for transfer to the sites where it is used directly as a raw material or burned and hydrated to phosphoric acid. During shipping, the phosphoms is allowed to soHdify in the cars. The railcars are commonly double walled with a jacket that can be heated with steam or hot water so that the phosphoms can be remelted on-site for transloading to local storage tanks. For overseas shipping, tanktainers with reinforced superstmcture for safe handling are used. Formerly, full tanker ships were in use. 

Unrefined alkylphenols are generally produced in the simple batch reactors described eadier. An alkene with between 8 and 12 carbon atoms reacts with phenol to produce a mixture of reactants, mono alkylphenols, and dialkylphenols. These mixtures usually do not free2e above 25 °C and so are Hquid at production and storage conditions. The product is generally used in the same factory or complex in which it is produced so shipment typically consists of pumping the material from the reactor to a storage tank. 

Ammonia is corrosive to akoys of copper and zinc and these materials must not be used in ammonia service. Iron or steel should usuaky be the only metal in ammonia storage tanks, piping, and fittings. It is recommended that ammonia should contain at least 0.2% water to prevent steel stress corrosion. Mercury thermometers should be avoided. 

Anodic passivation and its appHcation to sulfuric acid equipment such as stainless steel acid coolers and carbon steel storage tanks has been weU studied (102—104). More recently, sheU and tube coolers made from Sandvik SX or Saramet have been installed in several acid plants. These materials do not requHe anodic protection. 

---