Use of plasma technology in creating catalysts on carriers

Rutkovskii, A. E.; Vishnyakov, L. R.; Chekhovskii, A. A.; Kirkun, N. I.

doi:10.1007/bf02678646

Cited by 6 publications

(5 citation statements)

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“…For example, the plasma method only takes a single step with 8 parameters to control, while the other procedures require 6 stages, with overall control of about 40 different parameters. Other observed advantages of plasma technology include shortened preparation time, uniformity in quality of materials, achieving highly distributed and, consequently, smaller nanometric size metal particles and active species, superior catalytic performance, and enhanced catalyst lifetime, with overall lower energy requirements …”

Section: Discussionmentioning

confidence: 99%

Synthesis and Characterization of Co/C and Fe/C Nanocatalysts for Fischer–Tropsch Synthesis: A Comparative Study Using a Fixed-Bed Reactor

Aluha

Boahene

Dalai

et al. 2015

Ind. Eng. Chem. Res.

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Production of Fischer–Tropsch catalysts is challenging because it involves controlling and optimizing multiple parameters in numerous technical steps. Here, we present C-supported nanometric Fe and Co catalysts synthesized by plasma spraying, a method that contracts catalyst production into a single step, in contrast to traditional multistep catalyst production by precipitation or impregnation. The catalysts were reduced in situ and then tested for Fischer–Tropsch synthesis in a gas–solid fixed-bed reactor at 230 °C and 30-bar pressure for 24 h. The performance of plasma-synthesized catalysts was superior at a gas hourly space velocity of 6,000 mL·g cat –1·h–1, with Fe/C catalysts showing about 30% CO conversion per pass while Co/C catalysts yielded about 20% CO conversion. Identical C-supported Co and Fe catalysts prepared by impregnation or precipitation gave CO conversions of about 7% under similar reaction conditions.

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Section: Discussionmentioning

confidence: 99%

Synthesis and Characterization of Co/C and Fe/C Nanocatalysts for Fischer–Tropsch Synthesis: A Comparative Study Using a Fixed-Bed Reactor

Aluha

Boahene

Dalai

et al. 2015

Ind. Eng. Chem. Res.

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“…For example, although numerous process variables are necessary to provide the versatility needed to fabricate complex catalysts, plasma is a single-step method that decreases the number of stages in catalyst preparation, an approach that significantly lowers excessive process variables and parameters. [2] Other proposed advantages include superior catalyst performance, [3] achieved from the highly distributed active species, enhanced catalyst lifetime, shortened preparation time, and overall lower energy requirements, especially in cold plasma applications. [4] The nature and operation of the active species in the FTS catalysts are of substantial interest, having been studied using many characterization methods such as X-ray techniques (EXAFS, XRD, XPS), microscopy (SEM, TEM), [5] temperature-programmed reduction or oxidation (TPR/TPO), and adsorption techniques, namely physisorption and chemisorption, [6] among others.…”

Section: Introductionmentioning

confidence: 99%

“…For example, although numerous process variables are necessary to provide the versatility needed to fabricate complex catalysts, plasma is a single‐step method that decreases the number of stages in catalyst preparation, an approach that significantly lowers excessive process variables and parameters . Other proposed advantages include superior catalyst performance, achieved from the highly distributed active species, enhanced catalyst lifetime, shortened preparation time, and overall lower energy requirements, especially in cold plasma applications …”

Section: Introductionmentioning

confidence: 99%

Low‐temperature Fischer‐Tropsch synthesis using plasma‐synthesized nanometric Co/C and Fe/C catalysts

et al. 2016

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In this study, two analogous nanometric catalysts consisting of carbon-supported cobalt or iron (Co/C and Fe/C) were synthesized by plasma and tested for Fischer-Tropsch synthesis (FTS) in a continuously-stirred tank slurry reactor (CSTSR). Being pyrophoric in nature, these new materials were reduced in situ at 673 K (400 8C) for 24 h using pure H 2 gas. The FTS reaction was conducted at 493 K (220 8C), 2000 kPa pressure, and gas hourly space velocity (GHSV) of 3600 mL Á g Ar for mass balance determination. Devoid of promoters and under similar reaction conditions, the Co/C catalyst showed higher CO conversion (42 %) than the Fe/C (25 %), benchmarked against the commercial Fe-NanoCat 1 (32 %). Co/C was more selective toward gasoline production, while Fe/C was more selective toward the diesel fraction. From transmission electron microscopy (TEM) analysis, no significant change in the mean particle size ($12 nm) was observed in the plasma-synthesized catalysts before and after FTS reaction, implying that the catalysts did not sinter. Additionally, there were no internal mass transport limitations in these catalysts, making them favourable for FTS. Besides metallic species, X-ray diffraction (XRD) analysis indicated the presence of carbides in fresh catalysts (Fe 3 C in Fe/C and Co 3 C in Co/C). Magnetite (Fe 3 O 4 ) was the most prevalent phase in the used Fe-NanoCat 1 sample, a phase that was below the detection limits of XRD in the used plasma-synthesized Fe/C sample.

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“…Plasma technologies are becoming attractive due to the shortened catalyst preparation time involved, in addition to the lower energy requirements, production of highly distributed active species, enhanced selectivity, and catalyst lifetime [ 27 ]. Other characteristics presented by plasma synthesis include superior catalyst performance, with the activity and selectivity of the catalysts being higher than those for catalysts prepared by impregnation technology [ 28 ]. One disadvantage of the wet chemistry techniques that the plasma technologies can easily overcome, is the requirement for stringent control of numerous synthesis parameters and conditions [ 29 ], which lowers the process efficiency.…”

Section: Introductionmentioning

confidence: 99%

Use of Plasma-Synthesized Nano-Catalysts for CO Hydrogenation in Low-Temperature Fischer–Tropsch Synthesis: Effect of Catalyst Pre-Treatment

et al. 2018

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A study was done on the effect of temperature and catalyst pre-treatment on CO hydrogenation over plasma-synthesized catalysts during the Fischer–Tropsch synthesis (FTS). Nanometric Co/C, Fe/C, and 50%Co-50%Fe/C catalysts with BET specific surface area of ~80 m2 g–1 were tested at a 2 MPa pressure and a gas hourly space velocity (GHSV) of 2000 cm3 h−1 g−1 of a catalyst (at STP) in hydrogen-rich FTS feed gas (H2:CO = 2.2). After pre-treatment in both H2 and CO, transmission electron microscopy (TEM) showed that the used catalysts shifted from a mono-modal particle-size distribution (mean ~11 nm) to a multi-modal distribution with a substantial increase in the smaller nanoparticles (~5 nm), which was statistically significant. Further characterization was conducted by scanning electron microscopy (SEM with EDX elemental mapping), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The average CO conversion at 500 K was 18% (Co/C), 17% (Fe/C), and 16% (Co-Fe/C); 46%, 37%, and 57% at 520 K; and 85%, 86% and 71% at 540 K respectively. The selectivity of Co/C for C5+ was ~98% with 8% gasoline, 61%, diesel and 28% wax (fractions) at 500 K; 22% gasoline, 50% diesel, and 19% wax at 520 K; and 24% gasoline, 34% diesel, and 11% wax at 540 K, besides CO2 and CH4 as by-products. Fe-containing catalysts manifested similar trends, with a poor conformity to the Anderson–Schulz–Flory (ASF) product distribution.

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Use of plasma technology in creating catalysts on carriers

Cited by 6 publications

References 0 publications

Synthesis and Characterization of Co/C and Fe/C Nanocatalysts for Fischer–Tropsch Synthesis: A Comparative Study Using a Fixed-Bed Reactor

Synthesis and Characterization of Co/C and Fe/C Nanocatalysts for Fischer–Tropsch Synthesis: A Comparative Study Using a Fixed-Bed Reactor

Low‐temperature Fischer‐Tropsch synthesis using plasma‐synthesized nanometric Co/C and Fe/C catalysts

Use of Plasma-Synthesized Nano-Catalysts for CO Hydrogenation in Low-Temperature Fischer–Tropsch Synthesis: Effect of Catalyst Pre-Treatment

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