Hydrocarbons methanol conversion

Methanol conversion to hydrocarbons over various zeolites (370X, 1 atm, 1 LHSV)... [Pg.163]

The effect of the Si/Al ratio of H-ZSM5 zeolite-based catalysts on surface acidity and on selectivity in the transformation of methanol into hydrocarbons has been studied using adsorption microcalorimetry of ammonia and tert-butylamine. The observed increase in light olefins selectivity and decrease in methanol conversion with increasing Si/Al ratio was explained by a decrease in total acidity [237]. [Pg.244]

Fig. 2 Autocatalysis and retardation during methanol conversion on HZSM5 (left) and HUSY (right) at different temperatures. Yield of hydrocarbons (yield of coke neglected) as a function of duration of the experiment (inlet Pruonu =2.5 bar, WHSV = 1 h ) Catalysts HSZM5 Si/Al = 26, obtained from DEGlTSSiii HUSY basic cracking catalyst Si/Al = 4.5, obtained from Engelhard.

Fig. 6 Schematic drawing of ZSM5 catalyst bed deactivation. View of the fused silica reaction tube at about 40 % of catalyst life time. Black zone (I) of deactivated catalyst particles covered with coke ("methanol coke"). Small dark reaction zone (II) in which methanol conversion to 100 % occurs. Blue/grey zone (III) of active catalyst on which a small amount of "olefin coke" produced by the olefinic hydrocarbon product mixture has been deposited on the crystallite surfaces. The quartz particles before and behind the catalyst bed (zones 0) remain essentially white.

The conversion of methanol is plotted as a function of NIL uptake in Fig. 2. From this figure it appears that ammonia uptake at 150°C reasonably correlates with methanol conversion at 150°C indicating that ammonia uptake is a measure of active sites upon which the reaction takes place. This finding supports the observation of Ai (47) that the oxidation of hydrocarbon is derived... [Pg.235]

The simultaneous investigation of the methanol conversion on weakly dealuminated zeolite HZSM-5 by C CF MAS NMR and UV/Vis spectroscopy has shown that the first cyclic compounds and carbenium ions are formed even at 413 K. This result is in agreement with UV/Vis investigations of the methanol conversion on dealuminated zeolite HZSM-5 performed by Karge et al (303). It is probably that extra-framework aluminum species acting as Lewis acid sites are responsible for the formation of hydrocarbons and carbenium ions at low reaction temperatures. NMR spectroscopy allows the identification of alkyl signals in more detail, and UV/Vis spectroscopy gives hints to the formation of low amounts of cyclic compounds and carbenium ions. [Pg.216]

Methanol Conversion to Hydrocarbons. The conversion of methanol to hydrocarbons requires the elimination of oxygen, which can occur in the form of H20, CO, or C02. The reaction is an exothermic process the degree of exothermicity is dependent on product distribution. The stoichiometry for a general case can be written as in Eq. (3.45) ... [Pg.117]

M. G. Block, R. B. Callen and J. H. Stockinger, The analysis of hydrocarbon products obtained from methanol conversion to gasoline using open tubular GC columns and selective olefin absorption , J. Chromatogr. Sci. 15 504-512 (1977). [Pg.404]

Complete Methanol Conversion - The major products of the MTG conversion are hydrocarbons and water. Consequently, any unconverted methanol will dissolve into the water phase and be lost unless a distillation step to process the very dilute water phase is added to the process. Thus, essentially complete conversion of methanol is highly preferred. [Pg.34]

It is noteworthy that components other than alumina often have detrimental chemical and physical effects on the catalyst. For example, Herman et al. (77) reported that addition of ceria to the Cu/ZnO catalyst lowered methanol conversion by a factor of 5, despite the presence of a large concentration of microparticulate copper metal. This effect was explained by the ability of ceria to drive copper from the active state in zinc oxide solution to inactive metallic copper. Chromia, which had been used as a component of catalysts for methanol for a considerable period of time, is a suitable structural promoter, but some preparations result in an increase of concentration of side products such as higher alcohols (39), dimethyl ether (47), or even hydrocarbons. [Pg.296]

The reaction mechanism for the conversion of methanol to hydrocarbons over molecular sieve catalysts has been extensively investigated over the past 25 years. It is widely accepted that methanol conversion initially proceeds through equilibration with DME. Early work with ZSM-5 showed that light olefins are then the initial hydrocarbon products, followed by heavier olefins, paraffins and aromatics (Figure 12.5) (2). [Pg.245]

CDTECH/Snamprogetti SpA MTBE Mixed C4 hydrocarbons High-conversion catalytic distillation process for MTBE using C4s and methanol 107 2000... [Pg.137]

C DTEC H/Sn am progetti SpA TAME Mixed C5 hydrocarbons High-conversion catayhc distillation process fro TAME production using C5s and methanol 29 2000... [Pg.138]

Early attempts to convert methanol into olefins were based on the zeolite ZSM-5. The Mobil MTO process was based on the fluidised bed version of the MTG technology. Conversion took place at about 500°C allegedly producing almost complete methanol conversion. However, careful reading of the patent Uterature indicates that complete methanol conversion may not have been achieved by this means. Because of incomplete conversion, there would be a necessity to strip methanol and dimethyl ether from water and hydrocarbon products in order to recycle unconverted methanol. In this variant, the total olefin yield is less than 20% of the products of which ethylene is a minor but not insignificant product. The major product is gasoUne. Ethylene is difficult to process and has to be treated specially. Claims that it is possible that ethylene can be recycled to extinction conflict with the known behaviour of ethylene in zeolite catalyst systems and have to be viewed with some suspicion. [Pg.215]

AIPO4 is isoelectronic with silica and, as such, readily forms glasses and Si02-like crystalline materials. As well, framework stmctmes similar to zeolites may be prepared by the use of amines as templates. Like zeolites, these are active in catalytic reactions such as methanol conversion to hydrocarbons (seeZeolites) As a ceramic material, AIPO4 is an infusible material that is insoluble in water but is soluble in alkali hydroxides. It is often used with calcium sulfate and sodium silicate for dental cements. AIPO4 is also used as a white pigment that also acts as a corrosion inhibitor. [Pg.141]

Methanol conversion was adopted as a probe reaction to explore the catalytic activity of M" -TSM, because methanol is a simple molecule that transforms into easily assignable compounds and is converted into different products through different routes employing different catalysts. Methanol is decomposed into carbon monoxide and hydrogen over metal catalysts [including Ni (77)], is dehydrogenated into formaldehyde or methyl formate over Zn- or Cu-containing catalysts (78), and is dehydrated into dimethyl ether and successively into hydrocarbons over acid catalysts (79). [Pg.306]

Table IV summarizes the results of methanol conversion over the catalyst samples employed in the TPD study 30). The reaction was conducted in a conventional fixed-bed flow reactor under the conditions given in the table. The results are in agreement with those of the TPD measurement. Na - and H -TSMs are inactive for the methanol conversion, whereas Ti -TSM promotes dehydration, converting 50% of the fed methanol into dimethyl ether and a small amount of methane. The negligible activity of Li -Hect is improved slightly by exchanging the Li ion with and dramatically by exchanging Li with Ti. Na -Bent is an acidic clay. All of the three Bent catalysts, even Na -Bent, show higher activity than Ti -TSM, and the hydrocarbon yield reflects this difference in catalytic activity. Na -Bent is sufficiently active to give 60% conversion but has no ability subsequently to dehydrate dimethyl ether into hydrocarbons. The activity of H -Bent is higher than that of Na" -Bent, but the hydrocarbon yield is as low as 9%. As expected from the results of TPD measurement, the activity of Ti -Bent is remarkably high and converts 60% of fed methanol into hydrocarbons that are a mixture of methane, C2-5 olefins, and a small amount of Cs hydrocarbons.

We also studied the effect of ion exchange with on the catalytic activity of acid-treated Bent (H -Bent ), sometimes called activated clay. The results are given in Table IV. H" -Bent is virtually the same as H -Bent in catalytic activity. However, the catalytic activity of Ti -Bent for methanol conversion to hydrocarbons is much higher than that of Ti -Bent. The hydrocarbon yield reaches 90%, and the products, in addition to methane, are primarily olefins lower than Ce. The selectivity for olefin formation is estimated to be 90% or higher based on C2 and C3 hydrocarbon product distribution. Ti -Bent appears to surpass the phosphorus compound-modified zeolite proposed by Kaeding and Butter (31) in selective activity for olefin formation, and has the potential to exceed H-Fe-silicate (32) and Ni-SAPO-34 (33), proposed recently by Inui et al. [Pg.314]

The catalytic activity of heteroion-exchanged TSM, Ti Zn -TSM, is different from the activities of Ti - and Zn -TSMs. The results of the methanol conversion over the catalysts 35, 36) are summarized in Table V, which includes the data for Ti -TSM from Table IV. The reaction conditions are the same as given in Table IV. The heteroion-exchange reaction was conducted using a mixed solution of Ti(IV) and Zn(II) chlorides (mole ratio = 9 1). The resultant precipitate was washed with distilled water repeatedly and quickly to obtain Ti" Zn -TSM and Ti Zn -TSM/Cl, respectively. Ti -TSM catalyzes the dehydration of methanol to give dimethyl ether and a small amount of hydrocarbons, mainly methane, as described in the preceding section. The catalytic activity of Ti Zn -TSM is less than one-sixth as low as that of Ti -TSM, although only one-tenth of the Ti" in Ti -TSM has been replaced with Zn, inactive for the... [Pg.315]

Methanol conversion to hydrocarbons has been studied In a flow micro reactor using a mixture of C-methanol and ordinary C-ethene (from ethanol) or propene (from Isopropanol) over SAPO-34, H-ZSM-5 and dealumlnated mordenlte catalysts In a temperature range extending from 300 to 450 °C. Space velocities (WHSV) ranged from 1 to 30 h. The products were analyzed with a GC-MS Instrument allowing the determination of the Isotopic composition of the reaction products. The Isotope distribution pattern appear to be consistent with a previously proposed carbon pool mechanism, but not with consecutive-type mechanisms. [Pg.427]

On the other hand, it was proposed that acid catalyzed reactions such as skeletal isomerization of paraffin [2], hydrocracking of hydrocarbons [3] or methanol conversion to hydrocarbon [4] over metal supported acid catalysts were promoted by spillover hydrogen (proton) on the acid catalysts. Hydrogen spillover phenomenon from noble metal to other component at room temperature has been reported in many cases [5]. Recently Masai et al. [6] and Steinberg et al. [7] showed that the physical mixtures of protonated zeolite and R/AI2O3 showed high hydrocracking activities of paraffins and skeletal isomerization to some extent. [Pg.464]

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