Hydrocarbon fouling

Crittenden, B.D., and Kolaczkowski, S.T., 1979, Mass transfer and chemical kinetics in hydrocarbon fouling. Proc. Conf Fouling - Science or Art Inst. Cor. Sci. Tech, and I. Chem. E. University of Surrey, Guildford, 169 - 187. 

Further, these polymeric fillers are reducing the hydrocarbon fouling problem of PI membranes. Gas separation experiments show a dramatically enhanced gas separation performance for CO2 removal from natural gas. 

The normal regeneration temperature for siUca gel is 175°C. In hydrocarbon service, higher temperatures (225—275°C) are recommended to desorb heavy hydrocarbons, which tend to foul the adsorbent during prolonged use (see Silicon compounds). 

Ethyleneamines are used in certain petroleum refining operations as well. Eor example, an EDA solution of sodium 2-aminoethoxide is used to extract thiols from straight-mn petroleum distillates (314) a combination of substituted phenol and AEP are used as an antioxidant to control fouling during processing of a hydrocarbon (315) AEP is used to separate alkenes from thermally cracked petroleum products (316) and TEPA is used to separate carbon disulfide from a pyrolysis fraction from ethylene production (317). EDA and DETA are used in the preparation and reprocessing of certain... 

Aluminum oxide has been the most widely used catalyst (151). At 320°C and 1.01—1.42 MPa, 50—66% conversion to alcohol based on the ether was obtained. Ethanol produced by the direct hydration of ether generally has a foul odor owing to the presence of polymeric hydrocarbon material, which can be removed by washing the aqueous alcohol with ether (152). 

Zanker has presented a graphical technique for determining the fouling resistance (factor) for process or water fluid systems based on selected or plant data measurements, as shown in Figures 10-43A, 10-43B, and 10-43C. The design determination procedure presented by ZankeD is quoted here and used by permission from Hydrocarbon Processing... 

Figure 10-43A. Predict fouling by nomograph, Part 1. Calculation of R value for fouling factor use in conjunction with Figures 10-43B and 10-43C. (Used by permission Zanker, A., Hydrocarbon Processing. March 1978, p. 146. Gulf Publishing Company, Houston, Texas. All rights reserved.)...

Joshi, H. M., Mitigate Fouling to Improve Heat Exchanger Reliability, Hydrocarbon Processing, Y. 78, No. 1 (1999) p. 93. 

Oil and hydrocarbon leaks. FW system fouling and deposit binding Non-wettable boiler surfaces. 

Oil and hydrocarbon leaks that return with the condensate coat heat-exchange surfaces and cause FW system fouling and deposit binding. These materials must be removed or they will reenter the boiler to produce nonwettable boiler surfaces, and create serious problems. Oil in condensate should be removed by the use of an inline pre-coat filter. The pre-coating should be either aluminum hydroxide ox ferric hydroxide becaue both these hydrous oxide gels have an affinity for oil. 

Haines A process for recovering sulfur from natural gas, using a zeolite adsorbent. The hydrogen sulfide in the gas is adsorbed on the zeolite when the bed is saturated, hot sulfur dioxide is passed through it. The zeolite catalyzes the reaction between hydrogen sulfide and sulfur dioxide to fonn elemental sulfur, which sublimes out and is condensed. The process was invented by H. W. Haines in 1960 it was developed by Krell Associates and piloted in Canada from 1961 to 1962, but not commercialized because of problems caused by fouling of the zeolite with heavy hydrocarbons. 

Except for treated wastewater, almost all raw effluents contain solid compounds or grease and hydrocarbons responsible for fouling/clogging. As seen previously, on-site measurement is thus preferable, in order to place the instru-... 

Normally, treatment of coproduced groundwater during hydrocarbon recovery operations will include, as a minimum, oil-water separation and the removal of dissolved volatile hydrocarbon fractions (i.e., benzene, toluene, and total xylenes). In addition, removal of inorganic compounds and heavy metals (i.e., iron) is often required. Dissolved iron, a common dissolved constituent in groundwater, for example, may require treatment prior to downstream treatment processes to prevent fouling problems in air-stripping systems. Heavy metals removal is normally accomplished by chemical precipitation. 

Impure Feeds - Impure feeds cause Claus and Stretford plant problems (3,16). The most troublesome impurities are NH3, HCN, and hydrocarbons. These can cause catalyst fouling, plugging, chemical losses, and unstable operations. Remedies include catalytic conversion of impurities, use of special burners (16), and the use of different AGR processes to reduce the amounts of these compounds in acid gases. 

The corrosiveness of foul waters, hydrocarbons over 230°C (450°F), acids, and acid sludges may vary widely. Material recommendations should be obtained for each service. The material class indicated above will be satisfactory for many of these services, but must be verified. 

Many processes in a refinery use steam as a stripping medium in distillation and as a diluent to reduce the hydrocarbon partial pressure in catalytic or thermal cracking [37]. The steam is eventually condensed as a liquid effluent commonly referred to as sour or foul water. The two most prevalent pollutants found in sour water are H2S and NH3 resulting from the destmction of organic sulfur and nitrogen compounds during desulfurization, denitrification, and hydrotreating. Phenols and cyanides also may be present in sour water. 

The atmospheric bottom, also known as reduced oil, is then sent to the vacuum unit where it is further separated into vacuum gas oil and vacuum residues. Vacuum distillation improves the separation of gas oil distillates from the reduced oil at temperatures less than those at which thermal cracking would normally take place. The basic idea on which vacuum distillation operates is that, at low pressure, the boiling points of any material are reduced, allowing various hydrocarbon components in the reduced crude oil to vaporize or boil at a lower temperature. Vacuum distillation of the heavier product avoids thermal cracking and hence product loss and equipment fouling. 

Foul water, reflux drum water, water draw, and hydrocarbons containing these waters, including reflux streams < 175 > 175 < 350 > 350 All All S- 3 or S- 6 C-6 b... 

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