Heat exchanger tube fouling

Refinery management, 524-525 Refinery metallurgy, 415-429 metals used in refinery service, 415-416 stainless steel nomenclature, 416-418 corrosion resistance, 417, 419—426 embrittlement dangers, 426 rigorous service, 426-427 heat-exchanger tube fouling, 428 troubleshooting problems, 428... 

Walker, R. A. and T. A. Bott, An Approach to the Prediction of Fouling in Heat Exchanger Tubes from Existing Data, Trans. Instn. Chem. Eng., London, V. 51 (1977) pp. 165-167. 

Note that it is okay to heat softened or demineralized water to 160°F. You should not, however, do this with raw water. Calcium carbonate salts will plate out and foul the heat-exchanger tubes. 

Let s assume we have a new heat exchanger. The fluid on the tube side is crude oil. Crude oil, like many process fluids, will eventually foul and plug heat-exchanger tubes. The tendency to lay down fouling deposits is accelerated by... 

FIGURE 11 Cross section of a heat exchanger tube, with convective heat transfer in the fluids and fouling deposits on the surfaces. 

Anaiysis (a) The schematic of the heat exchanger is given in Fig, 11-11. The thermal resistance, for an unfinned shell-and-tube heat exchanger with fouling on both heat Iransfer surfaces is given by Eq. 11-8 as... 

Bott, T.R. and Walker, R.A., 1973, An approach to the prediction of fouling in heat exchanger tubes fi"om existing data. Trans. Inst. Chem. Engrs. 51, No. 2, 165. 

Hussain, 1982, Particulate magnetite fouling from flowing suspensions in simulated heat exchanger tubes. PhD Thesis, University of Birmingham. 

When a heat exchanger becomes fouled, fouling resistances inside and outside of tubes prohibit the heat exchanger from performing at the level as clean heat transfer coefficient. In practice, these two fouling resistances are lumped together into a total fouling resistance, R. The dirty heat transfer coefficient (C/d) can be expressed as... 

Preventing fouling of heat transfer surfaces, plugging of heat exchanger tubes etc. 

Fouling. In many applications, one or both fluids may cause corrosion of heat-exchanger tubes, and... 

Certain low-sulfur waxy crudes rapidly foul heat exchanger tubes. An easy method that has worked in some services to restore lost heat-transfer capacity partially is as follows ... 

Unstabilized austenitic stainless steel should not be used for U-tubes low carbon unstabdized stainless steels such as Type 304L or Type 316L are acceptable. Normally, air-cooled heat exchanger tubes should be carbon steel. For corrosive or heavy fouling services, the apphcation of internal coatings should be considered, if required. 

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