The effect of H2S on the selectivity of light alkenes in the FE-Mn-catalyzed Fischer-Tropsch synthesis

Hadadzadeh, Hassan; Mirzaei, Ali Akbar; Morshedi, Mahbod; Raeisi, A.; Feyzi, Mostafa; Rostamizadeh, Nader

doi:10.1134/s0965544110010123

Cited by 10 publications

(5 citation statements)

References 39 publications

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“…Other studies have been performed with sulfur promoted catalysts where the promoter was not added during the preparation of the catalyst but it was incorporated in the catalytic system through exposure to H 2 S. , Hadadzadeh et al investigated the effect of H 2 S poisoning on catalysts prepared by coprecipitation of Fe and Mn nitrates in the presence of a structural promoter (titania, silica, alumina, magnesia, or zeolite). Their results showed that the sulfur-poisoned catalysts exhibited higher ethylene and propylene selectivities and lower methane production and activity when tested at 450 °C, 1 bar, and H 2 /CO of 2.…”

Section: Fischer–tropsch To Olefins Process (Fto)mentioning

confidence: 99%

“…Another strategy used by several researchers to improve the catalytic performance of catalysts for the direct production of lower olefins from synthesis gas is the use of Fe-based bimetallic catalysts. Among them, Co–Fe ,,− and Fe–Mn ,,,,− , catalysts are the most studied systems. In the case of Co–Fe catalysts, the researchers intended to improve catalytic stability and activity of the already olefin-selective Fe catalysts by alloying it with a more active Fischer–Tropsch catalyst like Co.…”

Section: Fischer–tropsch To Olefins Process (Fto)mentioning

confidence: 99%

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Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

2013

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C 2 to C 4 olefins are traditionally produced from steam cracking of naphtha. The necessity for alternative production routes for these major commodity chemicals via non-oil-based processes has driven research in past times during the oil crises. Currently, there is a renewed interest in producing lower olefins from alternative feedstocks such as coal, natural gas, or biomass, in view of high oil prices, environmental regulations, and strategies to gain independence from oil imports. This review describes the major routes for the production of lower olefins from synthesis gas with an emphasis on a direct or single step process, the so-called FTO or Fischer−Tropsch to olefins process. The different catalysts for FTO are outlined and compared, and the key issues and requirements for future developments are highlighted. Iron-based catalysts are prevailing for FTO, and reproducible lower olefin selectivities of 50 wt % of hydrocarbons produced have been realized at CO conversions higher than 70% for 60 to 1000 h on stream. Remarkably the high selectivity to lower olefins has been achieved over a broad range of process conditions (P, T, H 2 /CO ratio, GHSV). A major challenge for further development and application of FTO catalysts is the suppression of carbon lay-down to enhance catalyst lifetime and to preserve their physical integrity under demanding reaction conditions.

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Section: Fischer–tropsch To Olefins Process (Fto)mentioning

confidence: 99%

Section: Fischer–tropsch To Olefins Process (Fto)mentioning

confidence: 99%

Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

2013

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“…The effect of S on FTO remains obscured. Although it was considered as a poison for Fischer–Tropsch catalysts, recent studies have showed it is able to improve CO conversion, decrease CH 4 selectivity, and increase lower olefins selectivity . De Jong et al.…”

Section: Introductionmentioning

confidence: 99%

Monodisperse Nano‐Fe₃O₄ on α‐Al₂O₃ Catalysts for Fischer–Tropsch Synthesis to Lower Olefins: Promoter and Size Effects

et al. 2017

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The Fischer–Tropsch synthesis to lower olefins (FTO) is a desirable nonpetroleum‐based route to produce basic chemicals. A novel two‐step method was applied to synthesize iron‐based supported catalysts, which is to prepare nano‐Fe3O4 first by thermal decomposition method and sequentially load them on α‐Al2O3 by impregnation. TEM and XRD results manifested that the controllable, uniform Fe3O4 nanoparticles are monodispersed on the surface of α‐Al2O3. H2‐TPR demonstrated that the reduction of Fe species was facilitated because of the weak interaction between Fe species and the support. These superior properties contribute to an enhanced catalytic activity and stability compared with the catalyst prepared by directly impregnating ammonium iron citrate on α‐Al2O3. Then, the effect of promoters was investigated at the same Fe loading and nanoparticle size. The appropriate addition of K could enhance the catalytic activity and suppress the secondary hydrogenation. On the contrary, S has a negative impact on CO conversion and strongly decreases C5+ selectivity. Particularly, the combination of K and S could obtain more pronounced CO conversion and higher lower olefins selectivity (≈40 %). Furthermore, size effects were explored by precisely tailoring the iron oxide particle size with the Fe loading kept constant. It was found that 12.0 nm nano‐Fe3O4 on α‐Al2O3 with or without K plus S promoters showed the best catalytic activity among the catalysts with different particle size.

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“…Furthermore, a number of sulfur studies (online or offline feeding) have also been reported for Fe and Co based FTS catalysts [2,[8][9][10][11][12][13][14][15][16][17][18]. The results are somewhat controversial due to the complexities involved.…”

Section: Introductionmentioning

confidence: 99%

Fischer–Tropsch synthesis: Effect of ammonia in syngas on the Fischer–Tropsch synthesis performance of a precipitated iron catalyst

Jacobs

Sparks

et al. 2015

Journal of Catalysis

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The effect of ammonia in syngas on the Fischer-Tropsch Synthesis (FTS) reaction over 100 Fe/5.1 Si/2.0 Cu/3.0 K catalyst was studied at 220-270 o C and 1.3 MPa using a 1-L slurry phase reactor. The ammonia added in syngas originated from adding ammonia gas, ammonium hydroxide solution or ammonium nitrate (AN) solution. A wide range of ammonia concentrations (i.e., 0.1-400 ppm) was examined for several hundred hours. The Fe catalysts withdrawn at different times (i.e., after activation by carburization in CO, before and after cofeeding contaminants, and at the end of run) were characterized by ICP-OES, XRD, Mössbauer spectroscopy, and synchrotron methods (e.g., XANES, EXAFS) in order to explore possible changes in the chemical structure and phases of the Fe catalyst with time; in this way, the deactivation mechanism of the Fe catalyst by poisoning could be assessed. Adding up to 200 ppmw (wt. NH 3 /av. Wt. feed) ammonia in syngas did not significantly deactivate the Fe catalyst or alter selectivities toward CH 4 , C 5+ , CO 2 , C 4-olefin and 1-C 4 olefin, but increasing the ammonia level (in the AN form) to 400 ppm rapidly deactivated the Fe catalyst and simultaneously changed the product selectivities. The results of ICP-OES, XRD and Mössbauer spectroscopy did not display any evidence for the retention of a nitrogen-containing compound

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The effect of H2S on the selectivity of light alkenes in the FE-Mn-catalyzed Fischer-Tropsch synthesis

Cited by 10 publications

References 39 publications

Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

Monodisperse Nano‐Fe₃O₄ on α‐Al₂O₃ Catalysts for Fischer–Tropsch Synthesis to Lower Olefins: Promoter and Size Effects

Fischer–Tropsch synthesis: Effect of ammonia in syngas on the Fischer–Tropsch synthesis performance of a precipitated iron catalyst

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The effect of H2S on the selectivity of light alkenes in the FE-Mn-catalyzed Fischer-Tropsch synthesis

Cited by 10 publications

References 39 publications

Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

Catalysts for Production of Lower Olefins from Synthesis Gas: A Review

Monodisperse Nano‐Fe3O4 on α‐Al2O3 Catalysts for Fischer–Tropsch Synthesis to Lower Olefins: Promoter and Size Effects

Fischer–Tropsch synthesis: Effect of ammonia in syngas on the Fischer–Tropsch synthesis performance of a precipitated iron catalyst

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Monodisperse Nano‐Fe₃O₄ on α‐Al₂O₃ Catalysts for Fischer–Tropsch Synthesis to Lower Olefins: Promoter and Size Effects