Partial oxidation Shell

Fif. 1.7. Hydrogen munuracturu hy partial oxidation. Shell process. 

A. Partial oxidation (Shell Gasification or catalytic partial oxidation)... 

Strelzoff, S. (1974), Partial oxidation for syngas and fuel (comparaison des precedes Texaco, Shell et Union Carbide) . Hydrocarbon processing, Vol. 53, No. 12, p. 79. 

Oxidation Step. A review of mechanistic studies of partial oxidation of propylene has appeared (58). The oxidation process flow sheet (Fig. 2) shows equipment and typical operating conditions. The reactors are of the fixed-bed shell-and-tube type (about 3—5 mlong and 2.5 cm in diameter) with a molten salt coolant on the shell side. The tubes are packed with catalyst, a small amount of inert material at the top serving as a preheater section for the feed gases. Vaporized propylene is mixed with steam and ak and fed to the first-stage reactor. The feed composition is typically 5—7% propylene, 10—30%... 

Noncatalytic partial oxidation of residual fuel oil accounts for the remainder of world methanol production. Shell and Texaco ate the predominant hcensors for partial oxidation technology (16) the two differ principally in the mechanical details of mixing the feedstock and oxidant, in waste heat recovery, and in soHds management. 

Ammonia production by partial oxidation of hydrocarbon feeds depends to some degree on the gasification step. The clean raw synthesis gas from a Shell partial oxidation system is first treated for sulfur removal, then passed through shift conversion. A Hquid nitrogen scmbbiag step follows. 

Electron transport is impossible in closed shell systems (the moving electron would have to occupy an antibonding orbital) and in half-filled open shell systems (spin pairing would prohibit the transport of electrons). Only the existence of hole states in partially oxidized dithiolenes allows electrons to flow freely. 

ER E has studied these alternatives for the utilization of coal liquefaction bottoms in the production of hydrogen and fuel gas and in doing so has had discussions of partial oxidation with Texaco and Shell. These studies have identified a potentially attractive processing sequence utilizing FLEXICOKING to produce additional liquids and plant fuel, and partial oxidation to produce hydrogen. 

ER E discussions with Texaco and with Shell on bottoms processing are summarized herein. Texaco has indicated that its partial oxidation process could be applied to coal liquefaction bottoms on a commercial scale and that operation of their 12 T/D pilot plant with coal liquefaction bottoms representative of a projected commercial feedstock would be adequate to set the design basis for a commercial facility. Texaco indicated that three to four years after successful operation of the 12 T/D unit a commercial facility could be ready for startup. In initial discussions, Shell has indicated that development of the Shell/ Koppers partial oxidation process for coal liquefaction bottoms would involve operations of both their 6 T/D pilot plant and their 150 T/D demonstration unit. It was estimated that the 150 T/D facility might become available in the late 1980/early 1981 time frame for possible operation on vacuum bottoms. 

Discussions with Texaco and Shell will continue in order to pursue further application of partial oxidation for coal liquefaction bottoms. 

The Entrained system is a high temperature, high reaction rate process in which coal, oxygen (or air) and steam combine rapidly to produce LBG or MBG. The commercial processes aim primarily at the use of oxygen. Several developmental processes use oxygen or air. The most widely used commercial process (Koppers-Totzek) is operated at atmospheric pressure. The Texaco partial oxidation process used with oil and gas is under development for use with coal. Shell and Koppers are developing a pressurized version of the current Koppers-Totzek process. The advantages of the entrained... 

The conditions are substantially more favorable for the microporous catalytic membrane reactor concept. In this case the membrane wall consists of catalyti-cally active, microporous material. If a simple reaction A -> B takes place and no permeate is withdrawn, the concentration profiles are identical to those in a catalyst slab (Fig. 29a). By purging the permeate side with an inert gas or by applying a small total pressure difference, a permeate with a composition similar to that in the center of the catalyst pellet can be obtained (Fig. 29b). In this case almost 100% conversion over a reaction length of only a few millimeters is possible. The advantages are even more pronounced, if a selectivity-limited reaction is considered. This is shown with the simple consecutive reaction A- B- C where B is the desired product. Pore diffusion reduces the yield of B since in a catalyst slab B has to diffuse backwards from the place where it was formed, thereby being partly converted to C (Fig. 29c). This is the reason why in practice rapid consecutive reactions like partial oxidations are often run in pellets composed of a thin shell of active catalyst on an inert support [30],... 

Non-catalytic partial oxidation (POX) of hydrocarbons from residual fuel oils to methane is commercially proven by two processes, one offered by Texaco and the other by Shell. Davy has experience with both processes. Each process has a large number of plants in operation, with feeds varying from natural gas to high sulfur residual oil. (In fact, so long as the feedstock can be pumped, it is a suitable feestock for a partial oxidation gasifier. 

Carbon nanotubes have been successfully used as removable templates for the synthesis of a variety of oxide nanotubes. Ajayan et al.9 reported the preparation of V205 nanotubes by using partially oxidized carbon nanotubes as templates. Apart from coating of CNTs by the oxide phase, metal oxide fillings in the internal cavities and thin oxide layers between the concentric shells of the tubes were also obtained (Fig. 30). A mix-... 

Synthesis gas manufacture by partial oxidation or autothermal cracking of crude oil fractions was developed by BASF/Lurgi, Texaco and Hydrocarbon Research. Heat for the thermal cracking is supplied by partial combustion of the feed in the presence of water. Recycled C02 may also be added to the combustion to attain a desired CO/H2 ratio. Shell developed a modified version (which does not... 

The noncatalytic partial oxidation of hydrocarbons by the Shell gasification process (SGP) takes place in a refractory-lined reactor that uses a specially designed burner. The oxidant is preheated and then mixed with steam... 

Figures 1.6 and 1.7 offer a schematic representation of units of the Texaco and Shell type, whose special feature is to recover the carbon formed by washing with tvater, and then to extract the sludge obtained with naphtha. The extract can then be homogenized with the feed and thus sent directly to the partial oxidation reactor (Shell version), or previously treated by stripping by reboiling in the presence ofheavier hydrocarbons, such as fiiel oil or crude oil, in order to separate and recycle the naphtha (Texaco version).

In the above radical-cation salts, the crystal contains partially oxidized donors, while the electroneutrality is achieved by the presence of closed shell anions. The structural requirements necessary for electrical conductivity in solid salts can also be met upon mixing of donors and acceptors in the resulting charge-transfer (CT) complexes both the donor and acceptor exist in a partially oxidized and reduced state, respectively. Famous examples are the conducting CT complexes formed upon mixing of perylene (112) [323. 324] and iodine or of tetrathiafulvalene (TTF, 119) as donor and 7,7,8,8-tetracyanoquinodimethane (TCNQ, 120) as acceptor [325-327] the crucial structural finding for the... 

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