Tannin Programs

Tannins are water-soluble vegetable products, usually blends of natural extracts from certain trees (similar to lignins and their derivatives 

Tannins make excellent BW inhibitors. They are multifunctional, possessing several characteristics that make them entirely suitable for the treatment of HW heating and LP steam boilers. They also are generally suitable for use in industrial and process WT boilers at pressures of up to 650 or even 950 psig. 

Tannins have been available for over 100 years (since about 1880), although even today their chemistry is still imperfectly understood. Moreover, they have been seriously undervalued within the global BW treatment marketplace, except by a few noteworthy water treatment chemical and service companies. 

NOTE The British Standards Institution provided only a cursory mention of tannins in BS 2486 1978 (Treatment of Water for Land Boilers), but the 1997 revision (Treatment of Water for Steam Boilers and Water Heaters) refers quite extensively to tannins and their usefulness. 

Although tannins are almost always formulated as a blend of raw materials, some knowledge of tannin chemistry is required because certain tannin constituents are useless in BW formulations and others lack 

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Effective metal waterside surface passivation (using hydrazine, DEHA, tannin, or similar products) remains an essential requirement of higher temperature or pressure system programs. 

Alkalinity boosters, which are vitally necessary to enable carbonate, phosphate, balanced polymer (polymer plus phosphate or chelant), and some other program types to function, are perhaps best described as conjunctional treatments, whereas oxygen scavengers, antifoams, and condensate line corrosion inhibitors are adjuncts. Programs such as phosphate-tannin mixtures are sometimes described as adjunct treatments. The chemistries and applications of various types of conjunctional treatments and adjuncts are described in this chapter. 

Tannin-Based Chemistry Multiblend, One-Drum Programs Materials Formulation... 

As important as validation studies for synthetic samples are in running a successful discovery program, they are even more important for running natural product samples and especially plant extracts, which are notoriously difficult to run in biochemical or enzyme-based screens. Tannins in particular are responsible for nonspecifically inhibiting activities in such screens. Other nuisance compounds include chlorophyll, melanin, lipids, and waxes. 

The rapid growth of the pulp and paper industry following World War II coupled with a renewed scientific interest in utilization of bark and wood residues led to investigative programs on bark and wood tannins. The leather industry was continuing to decline in importance, so other alternatives were needed. One of these was replacement of phenol in whole or in part in phenol-formaldehyde adhesive formulations. This work progressed to the point where commercial quantities of polyphenolic extractives were made and sold for adhesive application. Excessive capacity and low petrochemically derived phenol prices in the 1960 s led to the demise of this effort in the United States (2,5). 

Although preliminary studies suggest that face-laminations can be obtained using adhesives made from condensed tannins that pass the standards of the American Institute of Timber Construction (< ), less is known about how to formulate adhesives using these materials for end-jointing of wood. This study, funded by the USDA Small Business Innovation Research Program, was undertaken to develop adhesive formulations containing 50% of sulfite extracts obtained from the bark of southern pine trees and demonstrate their use in... 

Kreibich, R. E., Use of Bark Tannins in End-Joint Adhesives for Wood. Final Report-Phase I to the USDA Small Business Innovation Research Program on grant 86-SBIR-8-0126, R. E. Kreibich, Auburn WA., 1987. 

The new trend in cereal breeding programs is to select genotypes with special uses and with better nutraceutical properties. These new genotypes are rich in carotenes (P-carotenes, lutein, zeaxanthin), phytosterols, phenolics, anthocyanins, tannins, and other antioxidants. These value-added grains will gradually gain market because of their proven health benefits. 

Noiret (NY 65.0467.08 x Steuben, 2006). As with Corot noir, Noiret is a red wine grape cultivar released from the Geneva program in 2006 (Reisch et al., 2006b). It is also moderately winter hardy and resistant to disease, ripening in late September/ early October. Wines are dark-coloured, with intense aromas of dark fruits and black pepper. Noiret is also noted as one of the few eastern red wine cultivars with tannin. 

Thanks to Kenna Butler and Suzanne M. Bourret for providing flnorescence spectra, and to Tamara Kraus for providing well characterized tannin samples. Thanks also to Laurel Larsen, Robert Spencer, and two anonymous reviewers for providing aitical feedback during the writing of this chapter. Support was provided by the U.S. Geological Survey, National Research Program. 

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