Petroleum Processing Temperatures

The heavy vacuum bottoms stream is fed to a Flexicoking unit. This is a commercial (125,126) petroleum process that employs circulating fluidized beds at low (0.3 MPa (50 psi)) pressures and intermediate temperatures, ie, 480—650°C in the coker and 815—980°C in the gasifier, to produce high yields of hquids or gases from organic material present in the feed. Residual carbon is rejected with the ash from the gasifier fluidized bed. The total Hquid product is a blend of streams from Hquefaction and the Flexicoker. 

Diluents, mainly volatile aliphatic or aromatic hydrocarbons such as petroleum ether, dodecylbenzene or glycols, are often added to PVC pastes to lower the viscosity. These do not have a gelling effect and are evaporated off before gelation is commenced to prevent fine cracks or bubbles in the coating. Pigments for this application are required to have adequate resistance to the solvents used at the processing temperatures. 

Figure 17.15. A fired heater as a high temperature reactor, (a) Arrangement of tubes and burners (1) radiant tubes (2) radiant panel burners (3) stack (4) convection chamber tubes (Sukhanov, Petroleum Processing, Mir, Moscow, 1982). (b) Radiant (surface-combustion) panel burner (1) housing (2) ceramic perforated prism (3) tube (4) injector (5) fuel gas nozzle (6) air throttle Sukhanov, Petroleum Processing, Mir, Moscow, 1982). (c) Fired tubular cracking furnace for the preparation of ethylene from naphtha.

To the extent that viscosity and surface viscosity influence foam stability, one would predict that stability would vary according to the effect of temperature on the viscosity. Thus some petroleum industry processes exhibit serious foaming problems at low process temperatures, which disappear at higher temperatures. Ross and Morrison [25] cite some examples of petroleum foams that become markedly less stable above a narrow temperature range that may be an interfacial analogue of a melting point. 

Breck s preparation of type Y faujasite in die late 1950 s still stands as the outstanding success in zeolite synthesis (2). Type X might have had some catalytic applications but I doubt the International Zeolite Association would exist without the interest and support generated by the catalytic applications of the Type Y materials. It didn t seem that critical at the time after all Breck had reproduced a material which exists naturally. Synthetic counterparts of natural zeolites have been prepared dozens of times since (3). But die extra silica content, or perhaps die diminished alumina content, was enough to give high temperature stability in the acid form and to get zeolites into catalysts for petroleum processes (4). 

UNIDAK A process for extracting naphthalene from reformer residues in petroleum refining. It includes a dealkylation stage to convert the naphthalene homologues to naphthalene. The process temperature is approximately 600°C the catalyst is based on cobalt/molybdenum. Developed by the Union Oil Company of California. 

The BP (British Petroleum) process performs hydrogenation in two steps. The effluent from the first reactor contains 95 per cent weight cyclohexane. The reaction temperature is controlled by liquid and vapor recycles. Since the sensible heat and the heat of vaporization of the recycled cydohexane are used simultaneously, the redrculation ratio... 

Synthetic graphite is typically available in purities above 99%. High purity is the rule, rather than the exception with this material because the feedstocks used to make it are typically petroleum-based materials that are inherently low in mineral impurities, and the manufacturing method tends to expel impurities, which are vaporized at the high-process temperatures. This variety of graphite is available in sizes from 1.2 cm down to 3 j,m [15, 16, 18]. 

Although not as widely used as a gas-sofid PBR, FBR remains as the only choice for processes such as FCC and high-temperature Fischer-Tropsch (HTFT) synthesis, both of which have key roles in the petroleum processing and petrochemical industries. FCC is a critical step in petroleum refining and involves catalytic breakdown of heavy gas oil molecules into... 

In petroleum processing, sulfur compounds originate with crude oils and include polysulfides, hydrogen sulfide, mercaptans, aliphatic sulfides, disulfides, and thiophenes [32]. Corrosion by these sulfur compounds occurs between 260 C (500°F) and 538°C (1000°F). The corrosion rate increases with temperature to 454°C (850°F) and then decreases. Corrosion rate curves as a function of temperature for various steels with different chromium levels for a specific amount of sulfur in the processing streams are called McConomy curves [33] or modified McConomy curves [32], If the sulfur content in the system is different, a corrosion multiplier is then applied for varying stdfur amounts. In addition, Copper-Gormen curves have been developed for various alloys that predict corrosion rate with respect to temperature for a range of H2S composition [34]. 

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