Wood, corrosion resistance

The chief advantage of wood for containers is that many common species are free from harmful contaminants. For this reason wood had widespread use in the food and beverage industries, but it has now suffered severe competition from corrosion-resistant metals, plastics and paper products. Oak had a very extensive use in tight cooperage in the brewing industry, and its use for barrels still survives in the maturing of whisky and brandy and in the wine industries. Wood is particularly useful where acetic acid is present as this acid is corrosive to most common metals. 

Wood, one of people s oldest materials, remains an important (and too often, overlooked) corrosion-resistant material of construction in the chemical-process industry. Wood tanks and wood piping have long met engineers requirements for dependable service and excellent performance in industrial applications. A very thorough and detailed treatise can be found in a three-part publication, by Oliver W. Siebert, Wood—Nature s High-Performance Material, NACE, Materials Ferformance, vol. 31, nos. 1-3, January through March 1992. ... 

Depending on the technical requirements such as corrosion resistance, pressure and temperature stability, industrial scale azo pigment synthesis is carried out in appropriate equipment. Suitable materials include cast iron, stainless steel, steel lined with rubber, acid-proof brick, enamel, synthetic resins supported by glass fiber, and wood. 

Possible applications of foamed composites include buUding insulation, wood substitutes for applications which require corrosion resistance, high physical strength and light weight. Very recently, a large market for foamed composites has appeared in the automotive industry. One example is a door-trim panel (7). 

Foamed composites are lightweight materials having high strength, corrosion resistance and workability. Figure 54 shows the modulus vs density for various materials. In the figure, it is shown that natural wood has a higher modulus at relatively lower densities than other materials (1). 

For larger scales, shallow trays made of corrosion-resistant metal or plastic placed in portable trolleys may be used for efficient liquid-air contact. The trolleys are placed in a sterile room with frequent sterile air changes under closely controlled temperature and humidity conditions. Efficient air-liquid contact may also be obtained from a loosely packed, moist, solid medium permeated with air. For instance bran is used as the substrate for enzyme production by Aspergillus oryzal. Wine vinegar (acetic acid) is produced by trickling wine (basically ethanol in water) over a short tower of wood chips, which are used both as a support and to provide air to Acetobacter aceti [13] (Eq. 16.15). By law, the acetic acid (3-5% in water) in vinegar must be produced by fermentation, and not by petrochemical methods. 

RubCon can be used in specialized structures instead of traditional building materials (reinforced concrete, steel, wood). Comparison of technical and economic parameters of RubCon with the most widespread kinds of corrosion-resistant concretes, in particular polymer concrete based on epoxy and polyester resins, showed that the cost of a useful loading unit of the RubCon structure is more than twice as effective as epoxy polymer concrete and 2.2 times as effective as polyester polymer concrete. 

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