Reformate pretreatment

Oh, Y., Roh, H., Jun, K., Baek, Y. (2003). A highly active catalyst, Ni/Ce-Zr02/9-AljOj, for on-site Hj generation by steam methane reforming pretreatment effect. Int.. Hydrogen Energy 28,1387-1392. 

Catalytic cracking is another process to benefit from hydrotreating. The benefits are similar to those for reformate pretreatment longer runs, better cracking selectivity, and better product quality. Another advantage is reduced sulfur laydown on the cracking catalyst. Then, catalyst regeneration will contribute less sulfur dioxide to the atmosphere. 

For example, in the case of light Arabian crude (Table 8.16), the sulfur content of the heavy gasoline, a potential feedstock for a catalytic reforming unit, is of 0.036 weight per cent while the maximum permissible sulfur content for maintaining catalyst service life is 1 ppm. It is therefore necessary to plan for a desulfurization pretreatment unit. Likewise, the sulfur content of the gas oil cut is 1.39% while the finished diesel motor fuel specification has been set for a maximum limit of 0.2% and 0.05% in 1996 (French specifications). 

The conversion products, other than gas and hydrogen sulfide (H2S), are essentially a gasoline fraction that, after pretreatment, will be converted by catalytic reforming an average quality distillate fraction to be sent to the gas oil pool and an atmospheric residue or vacuum distillate and vacuum residue whose properties and impurity levels (S, N, Conr. 

A viable electrocatalyst operating with minimal polarization for the direct electrochemical oxidation of methanol at low temperature would strongly enhance the competitive position of fuel ceU systems for transportation appHcations. Fuel ceUs that directiy oxidize CH OH would eliminate the need for an external reformer in fuel ceU systems resulting in a less complex, more lightweight system occupying less volume and having lower cost. Improvement in the performance of PFFCs for transportation appHcations, which operate close to ambient temperatures and utilize steam-reformed CH OH, would be a more CO-tolerant anode electrocatalyst. Such an electrocatalyst would reduce the need to pretreat the steam-reformed CH OH to lower the CO content in the anode fuel gas. Platinum—mthenium alloys show encouraging performance for the direct oxidation of methanol. 

The composition of a reforming catalyst is dictated by the composition of the feedstock and the desired reformate. The catalysts used are principally platinum or platinum—rhenium on an alumina base. The purpose of platinum on the catalyst is to promote dehydrogenation and hydrogenation reactions. Nonplatinum catalysts are used in regenerative processes for feedstocks containing sulfur, although pretreatment (hydrodesulfurization) may permit platinum catalysts to be employed. 

Hydrofining is applied to virgin naphthas mainly in the form of a pretreatment step for the feed to catalytic reformers (Powerforming). Sulfur levels of 5 parts per million (ppm) or less are required to avoid deactivation of the platinum reforming catalyst. 

The catalyst (0.15 g) was loaded into a quartz tube reactor (internal diameter = 4 mm). The catalyst was pretreated in nitrogen at 400°C. Simulated gasoline reformate was used for the activity test of the catalyst. The composition of the simulated reformate was 36 wt% H2, 17 wt% CO2, 28 wt% N2, 17 wt% H2O, 1 wt% CO, and air was added additionally as the oxidant. The total flow rate was maintained at 100 ml/min. The test was performed over the temperature range of 120 280°C at various flow rates of inlet air. 

Pretreated NG feedstock is mixed with steam (2.6 MPa), the resulting mixture is preheated to 500°C and introduced to the catalytic reforming reactor. In the reforming reactor, the steam-methane mixture is passed through externally heated reformer tubes filled with Ni catalyst, where it is converted to CO and H2 at 850-900°C according to the following equation ... 

In the catalytic reforming of naphthas there are a number of nonhydrocarbon materials which play an important part in the performance of the catalyst. Sulfur is a poison for the reforming catalyst. There appears to be evidence developing that the platinum-rhenium catalysts may be more sensitive to sulfur than the conventional catalysts. Effective pretreatment of the feed stock to maintain sulfur at low levels is desirable. 

Bravo et al. [29] dealt with the coating of a commercial CuO/ZnO catalyst on quartz and fused-silica capillaries for future application in micro channels. The catalyst was mixed with boehmite as binder and water at a mass ratio of44 11 100. The boehmite was treated with hydrochloric or nitric acid before. The capillaries were pretreated with a hot sulfuric acid/solid oxidation step before coating. The capillaries were filled with the catalyst/binder suspension and then cleared with air. In this way, catalyst coatings up to 25 pm thick were obtained. The coatings were applied to methanol steam reforming (see Section 2.4.1). 

Chin, Y.-H., Wang, Y., Dagle, R. A., Li, X. S., Methanol steam reforming over Pd/ZnO catalyst preparation and pretreatment studies, Fuel Process. 

Persian Gulf (PG) 90-l40°C cut straight run naphtha is hydrodesulfurised in naphtha pretreater and is being processed in the referred industrial reformer The pretreated naphtha was procured from the refinery and used as charge for pilot plant studies at UP It s characteristics are presented in Table 2... 

Earlier studies in nickel catalysts resistance to coking in steam reforming showed that the carbon deposition rate depends not only on such direct factors as nickel dispersion [10] or the support composition [11], but also on indirect factors, connected with the preparation and pretreatment conditions of the systems, the latter influence the coking rate by causing changes of the direct factors [12]. 

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