Contaminant, origin condensable

Condensate contamination originates from several sources, including BW carryover into the generated steam, corrosion debris pickup... 

The reports were that water condensed from the vapor phase into 10-100-/im quartz or pyrex capillaries had physical properties distinctly different from those of bulk liquid water. Confirmations came from a variety of laboratories around the world (see the August 1971 issue of Journal of Colloid Interface Science), and it was proposed that a new phase of water had been found many called this water polywater rather than the original Deijaguin term, anomalous water. There were confirming theoretical calculations (see Refs. 121, 122) Eventually, however, it was determined that the micro-amoimts of water that could be isolated from small capillaries was always contaminated by salts and other impurities leached from the walls. The nonexistence of anomalous or poly water as a new, pure phase of water was acknowledged in 1974 by Deijaguin and co-workers [123]. There is a mass of fascinating anecdotal history omitted here for lack of space but told very well by Frank [124]. 

Foulants and contaminants may originate virtually anywhere in the overall steam-water circuit. Some may be derived from pre-boiler systems (such as an economizer or deaerator) or post-boiler systems (such as a steam trap or a condensate line), but they inevitably find their way into the boiler and cause significant damage and expense. 

Precipitated iron also acts as a binder and forms deposits with other materials. The source of iron originates either from contaminated condensate or from MU water, where it is present in the form of ferrous bicarbonate [Fe(HC03)2]. 

In addition, the development of porous deposits on boiler surfaces often is enhanced by the presence of small amounts of iron or copper oxides (usually originating from contaminated condensate). This increased rate of deposition may then lead to even more serious problems of overheating. 

Although oxygen and carbon dioxide are the most important corrosive gases found in steam-condensate systems, small amounts of other contaminant gases are usually present. These may originate in various ways, for example ... 

Water contamination of fuel occurs. Water can originate from fuel processing, atmospheric condensation, or external sources. Water may contain dissolved salts, may be acidic or basic, or may contain solubilized organic compounds. Water-initiated corrosion can result. 

By the same token, it originally demanded an enormous experimental effort to purify water by distillation and keep it free from contaminants such as C02 in order to prove that the pure substance indeed contains 10 7 M Haq and 10-7 M OH" in equilibrium. After S. P. L. Sprensen introduced the concept pH, it became plausible to determine pH by electrode potentials, first from the classical hydrogen electrode with finely divided platinum catalyst (the conditions for the standard oxidation potential E° to show its zero point is a monument for the difficulties when mixing thermodynamical prescriptions for gaseous and condensed matter ... 

We should caution that the above concept of the genetic relationship between kerogens and asphaltenes differs from the more historic view that asphaltenes are condensation and/or alteration products of hydrocarbons and resins. Certainly, in some petroleum processing treatments and probably at higher maturation levels in nature, various reactions do form new products with asphaltene solubility characteristics. These new condensation products may be regarded as altered asphaltenes and intermediates in the coke or pyrobitumen formation process (62-64)- Contamination of original asphaltenes by subsequently formed or altered products, of course, will result in a less definitive correlation between an asphaltene and its source kerogen. 

When removed from refrigerated storage, the adhesive must be brought to its application temperature, usually room temperature. The containers should remain closed until they are at temperature. A material is most vulnerable to moisture collection when it is removed from cold storage and the package or container is not properly sealed. Moisture condenses on the adhesive and quickly reduces its capabilities. Containers that are not completely used when originally opened, should be sealed immediately after use to prevent loss of volatile ingredients or contamination from moisture in the air. Equipment used to remove the contents from the containers, such as spatulas, flasks, and cups, should be cleaned between each use. 

It is well known that ACN reacts with active metals (Li, Ca) to form polymers [48], These polymers are products of condensation reactions in which ACIST radical anions are formed by the electron transfer from the active metal and attack, nucleophilically, more solvent molecules. Species such as CH3C=N(CH3)C=N are probably intermediates in this polymerization. ACN does not react on noble metal electrodes in the same way as with active metals. For instance, well-re-solved Li UPD peaks characterize the voltammograms of noble metal electrodes in ACN/Li salt solutions. This reflects a stability of the Li ad-layers that are formed at potentials above Li deposition potentials. Hence, the cathodic limit of noble metal electrodes in ACN solutions is the cation reduction process (either TAA or active metal cations). As discussed in the previous sections, with TAA-based solutions it is possible that the electrode surfaces remain bare. When the cations are metallic (e.g., Li+), it is expected that the electrode surfaces become covered with surface films originating from atmospheric contaminants reduction if the electrodes are polarized below 1.5 V (Li/Li+). As Mann found [13], in the presence of Na salts the polarization of metal electrodes in ACN solutions to sodium deposition potentials leads to solvent decomposition, with evolution of H2, CH4 and sodium cyanide (due to reaction with metallic sodium). 

Thus the condensation methods of formation of colloidal solutions, mainly from true ionic or molecular solutions, are most important in nature. The sols obtained nearly always are contaminated by various impurities, usually electrolytes, including components of the original true solutions. 

ERSA) samples of 59 wells in 29 oil, gas and gas-condensate fields were compiled from internal, proprietary Shell databases and Warren Smalley (1994). All data used were quality checked and contaminated samples or samples of dubious origin were excluded. Table 1 summarizes the fields, wells, sample location and formations from which the different types of sample were obtained. Field locations are shown in Fig. 1. Data were obtained from sandstone and sandstone/shale sequences at depths between 7300 and 19000 ft TVDSS. At these depths, reservoir temperatures and pressures are between 107 and 191 °C and between 323 and 1136 bars, respectively. 

Traces of heavy metals in waters are of industrial origin (waste waters from mining and treatment of ores, from metallurgical plants and rolling mills, metal finishing, photographic shops, from textile, leather, and chemical industry, and even from agriculture (e.g. cadmium from African phosphate fertilizers ). An additional source are atmospheric condensations contaminated by exhalations from combustion of fossile fuels and from motor vehicles. 

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