Acid-alkali modeling

Figure 3. Acid/alkali model of under port flames in an end-fired furnace...

Similar instrumentation to that used on the cross-fired pilot furnace was used. Testing the proposed auxiliary combustion injectors suggested by the acid/alkali modelling demonstrated that significant NOx reduction could be achieved as shown in Figure 13. 

Although testing had already been carried out on the GDF SUEZ Cross firedZMW pilot furnace that simulates a single port, it was important to understand the effect of the interaction between ports of a multiport furnace. To this end an Acid/Alkali model of the cross-fired furnace to be tested was buQt. This revealed the criticality of location and operating parameters of the Auxiliary Injectors on this type of furnace. It also suggested the changes that may be required to the operation of the side of port neck burners, which may be required when Auxiliary injection is applied. 

Flow Visualization Modeling (Acid-Alkali Modeling)... 

Experience has shown that for a confined flame, sufficient primary air jet momentum is required to create mixing via external recirculation zones. As the acid-alkali model shows, high momentum and, for that matter, intense and perhaps complete mixing, is tantamount to efficient combustion. We discussed in Chapter 4 that, for confined jets, the onset of flame recirculation can be described by the Craya-Curtet... 

Figure 6.10 Acid-alkali modeling of combustion in rotary kilns (a) low burner momentum, (b) high burner momentum.

Tetralin and 1-methylnaphthalene were reagent grade and were used after washing with sulfuric acid, alkali, and water and the subsequent distillation at 70°C under reduced pressure. Various additives and model compounds were reagent grade, and some of them were used after recrystallization. Phenyl naphthyl ether and phenyl 9-phenanthryl ether were synthesized by refluxing a mixture of aryl bromide, phenol, CU2O and X-collidine (12). 

An aqueous dope of forms gel with protonic acid, alkali, oxidizing and reducing agents as formulated below. The crosslinking of S-S type would be suggested since the formation of -SH or -S was confirmed for the model compound under the similar condition. 

Van Helmont, the most prominent of the seventeenth-century iatro-chemists, made the acid-alkali reaction the chemical model for a theory of animal digestion. One of his pupils, Sylvius by name, carried this idea into a total system by claiming that all bodily functions were acid-alkali reactions, and that all body fluids were either acidic or alkaline. This theory... 

TABLE 1 Effect of Alkali Concentration on Film Capacitance in Modeling Oil (7.5 mmol/L Oleic Acid)/Alkali Systems... 

In order to understand the flow patterns within the combustion chamber to allow selection of suitable Injection points and make initial evaluation of the likely effect, flow modelling was required. Both computational fluid dynamics (CFD) and acid/alkali physical modelling were used. 

This very separate class of pumps comes in four basic models, each with a different elastomer, capable of working with over 900 fluids including solvents, corrosive acids, alkalis, oils, pesticides and more. These fluids are found in every kind of facility, be it electronic, automotive or pharmaceutical manufacturing as well as golf courses, land care and highway maintenance departments. 

The isocyanurate reaction occurs when three equivalents of isocyanate react to form a six-membered ring, as shown in the fifth item of Fig. 1. Isocyanurate linkages are usually more stable than urethane linkages. Model compound studies show no degradation of the trimer of phenyl isocyanate below 270°C [10,11]. Catalysts are usually needed to form the isocyanurate bond. Alkali metals of carboxylic acids, such as potassium acetate, various quaternary ammonium salts, and even potassium or sodium hydroxide, are most commonly used as catalysts for the isocyanurate reaction. However, many others will work as well [12]. 

PETP flakes produced from used soft drinks bottles were subjected to alkaline hydrolysis in aqueous sodium hydroxide. A phase transfer catalyst (trioctylmethylammonium bromide) was used to enable the depolymerisation reaction to take place at room temperature and under mild conditions. The effects of temperature, alkali concentration, PETP particle size, PETP concentration and catalyst to PETP ratio on the reaction kinetics were studied. The disodium terephthalate produced was treated with sulphuric to give terephthalic acid of high purity. A simple theoretical model was developed to describe the hydrolysis rate. 17 refs. 

Amy Berger helped me write Chapter 10 (Surface Complexation), and Chapter 31 (Acid Drainage) is derived in part from her work. Edward Warren and Richard Worden of British Petroleum s Sunbury lab contributed data for calculating scaling in North Sea oil fields, Richard Wendlandt first modeled the effects of alkali floods on clastic reservoirs, and Kenneth Sorbie helped write Chapter 30 (Petroleum Reservoirs). I borrowed from Elisabeth Rowan s study of the genesis of fluorite ores at the Albigeois district, Wendy Harrison s study of the Gippsland basin, and a number of other published studies, as referenced in the text. 

Such studies, and others on an O-phosphonomannan155 and a tei-choic acid,168 relied on judicious comparisons (of shift) with signals of model compounds, and these are simpler than conventional, analytical procedures. For example, it is difficult to methylate alkali-labile O-phosphonomannans, and sialic acid and KDO-containing polymers would require difficultly available, O-methylated standards. In addition, periodate-oxidation analyses are restricted to polymers having fortuitously amenable, chemical structures. 

---