Reforming severity

The Clean Air Act Amendments of 1990 limit the amount of benzene in gasoline in the United States to 1% (7). Initially there was some concern that this would dismpt the benzene supply and demand balance in the chemical industry because at that time gasoline contained benzene above 1%. If refiners had to extract all of the benzene above 1%, substantial additional benzene would be produced. However, only modest increases in the quantity of benzene produced from reformer sources is expected as most refiners can adjust the composition of reformer feed and reformer severity to produce less benzene. 

Addition of ZSM-5 in a catalytic cracking unit can permit a reduction in reformer severity. At a given pool octane requirement, the higher FGG octane contribution (Research/Motor) allows for lower reformer severity and, consequently, higher reformate yields. At EniGhem s Gela FGG unit fl2-14). when ZSM-5 was in the FGG, the reformate severity dropped from 95.0 RON clear to 90.0 RON clear while liquid yield increased by 4% vol. 

Correlations presented in the middle thirties enabled the prediction of octane number improvement resulting from thermal reforming (7, 21). They have continued to appear in the literature (6, 20). Improvement of the octane number of naphthas has been the principal function of thermal reforming, but Egloff (8) discusses its usefulness also for the production of light olefins which provide feed stocks for alkylation or polymerization processes. To show the distinct improvement in the yield-octane relationship realized by the catalytic polymerization of C3 and C4 olefins produced by thermal reforming, Mase and Turner (16) present experimental data at various reforming severities for two naphthas. 

The ability of the Argonne catalyst to reform several types of hydrocarbons suggested that this catalyst would be able to reform commercial petroleum fuels. However, commercial fuels offer additional challenges to reforming. Gasoline and diesel fuels both contain sulfur,... 

The need for benzene reduction is one of the determining factors in the way refiners will have to modify their process portfolio to meet future specifications. Apart from lowering the reformer severity, pre-fractionation and post-fractionation provide viable tools to reduce benzene in the gasoline pool. Pre-fractionation and subsequent hydrogenation of benzene is a typical solution. However, the products (cyclohexane and alkyl-cyclohexanes) are low in octane. Therefore, this option is only feasible if the refinery is not short in octane. The octane loss can be compensated for by the addition of oxygenates or preferably by the addition of alkylates. If more octane is needed, post-fractionation is one of the solutions. 

A. Methane Reforming.—Several of the kinetic equations in Table 4 relating to CH4 reforming include a term (1 — K jK), where K is the equilibrium constant for the reforming reaction, e.g. (5) or (6), and K is pco. Ph IPch. Ph o for example for reaction (5), pco, etc. being the actual partial pressures of the gaseous components. The term is important under conditions near equilibrium because it takes into account the back reaction, the rate of which increases as equilibrium... 

Deactivation of supported nickel on alumina by coke and/or carbon formation is a serious problem in hydrocarbon steam reforming. Several ways have been used to prevent coke and/or carbon deposition. Among them certain additives (e.g. MgG, K2O) which promote... 

Under actual conditions of reforming, several species are chemisorbed on the Pt/Al203 surface and they influence the overall dynamics(l-6). Significant adsorbate-adsorbate interactions can be present and they affect the sorption and reaction rates and equilibrium (6-11) markedly, especially for bi-molecular reactions. These also can have pronounced consequences in surface dynamics(7-16). While their roles in surface phase transformations have been demonstrated, using ideal single crystal surfaces(12,13), their consequences in surface dynamics are much less understood.(l,12-14)... 

The CALCOR process is similar to a conventional steam methane reformer with an amine acid gas removal system, except that the CO2 from the amine system is recycled to the reformer furnace. The reformer operates at a very low pressure to reduce reforming severity. The synthesis gas from the CO2 removal system is just above atmospheric pressure. It is saturated with water and residual CO2 and must be compressed before entering downstream separation equipment. The process features a very low methane slip below 500 ppm in the synthesis gas [11]. 

Both an increase in the temperature and a decrease in the space velocity means a higher reforming severity, producing a reformate with higher octane number. In the case of a Midcontinent naphtha, changing LHSV from 3.0 to 1.25 h leads to a change in the octane number from 82.1 to 100.5. Doubling the space velocity is equivalent to decrease the temperature in 30-40° F approximately (4). 

Following the Mexican Government Reform, several scientific institutions and associations were founded during the late 19th and the early 20th centuries. Examples are The Mexican Society of Natural History (1868), The Geographic Exploitation Commission (1877), and The Antonio Alzate Scientific Society. One of the activities of such institutions was to publish compilations of data and descriptive matter very little research was included. 

The scale can be reformed several times after spalling as the concentration of chromium in the alloy is sufficiently high. 

The reformate stream also contains the largest concentration of benzene found in the gasoline pool (Table 7 Keesom 1991). Since light reformate is a major source of benzene in the gasoline pool e reduction in benzene requires not only a reduction in reformer severity but also feedstock shifts and additional downstream processing. Some of these processing steps include ... 

At the high operating temperature in the reformer, severe tube damage can result from carryover of boiler feed-water salts. The carryover of boiler feed-water salts can cause sulfidation and molten salt attack on the tubes, manifold, and transfer lines. Carbonization of methane and higher hydrocarbons will carburize most metals rapidly. Also, trace... 

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