Chemical reaction fouling

Thom and Byers (35) discussed the design and construction issues that can lead to the inaccurate model predictions compared to field observations in that liquid distribution, packing materials, fouling, chemical reaction, and end effects were of great importance. 

Chemical reaction fouling (ex.—Coking). Chemical reaction of the fluid takes place on the heat-transfer surface producing an adhering sohdprodiict of reaction. 

Unique system characteristics and special design features, e.g., corrosion, foaming, chemical reaction, and fouling, and designs to overcome such problems. 

Chemical reaction fouling deposits formed by chemical reaction in the fluid system. 

Chemical treatment. Any of a wide range of chemicals that prevent or reduce tendencies of fouling, scaling, corrosion, or other unwanted phenomena to occur in a cooling system. Typically individual inhibitors may interfere with a chemical reaction and are then blended to produce a multifunctional formulation, specific for certain controlled operating conditions. 

Chemical reaction fouling can also occur in the pasteurization of milk. Complex chemical deposits appear after a relatively short time so that, apart from overcoming the operational difficulties resulting from the accumulation of deposits, cleaning becomes essential to maintain hygienic conditions in the equipment. 

In addition to the organic character of fouling because of the chemical reactions in the petroleum industry, there might be a significant inorganic content including ... 

Dissolved oxygen and its concentration can have a profound effect on chemical reaction fouling rates. 

Crittenden observes that there are generally a minimum temperature below which fouling will not be observed and a critical upper temperature above which the deposition rate falls away because of the changes in the underlying reaction. Two aspects of fluid velocity have to be appreciated in connection with the effects of velocity on chemical reaction fouling heat and mass transfer, both of which are dependent... 

All kinds of interactions and combinations are possible. In cooling water, for instance, the deposits are likely to include micro-organisms, particles, scale, and corrosion products. In flue gas systems, the fouling may be because of particle deposition, chemical reaction, and corrosion. In crude oil processing, the deposits may be products of reaction, combined with particle deposition and corrosion. 

Slack management of operations and poor maintenance may give rise to accelerated and unexpected fouling. For instance, leaks across a heat exchanger, from one stream to the other, may introduce an unexpected and severe fouling problem, because of corrosion or chemical reactions. Again this can result in poor performance and may be expensive to rectify. 

Fouling as a result of chemical reaction is generally associated, although not exclusively, with the processing of crude oil and petroleum fractions. The mechanisms involved include polymerization of components because of the presence of metal ions, and oxygen and coking (break-down reactions) reactions. Chemical... 

In a program to combat fouling from chemical reactions, it is usual to employ a blend of chemicals to offer wide-ranging protection. Many of the additives available are proprietary and it will be necessary to seek the advice of the suppliers before applying to the process stream. 

These chemical reactions may either foul an operation or mobilize harmful substances. Geochemical modeling can be very useful in predicting potential problems, but has only found limited applications. 

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