A. Yu. Krylova

Fischer-Tropsch synthesis in a three-phase system with iron catalyst nanoparticles

The features of the Fischer-Tropsch synthesis in the presence of 100Fe: 8Al2O3: 3K2O (parts by weight) catalyst nanoparticles under the slurry reactor conditions have been studied. The catalyst is prepared in situ and activated in the reactor. It has been found that during the preparation process, the catalyst reacts with the dispersion medium to form a structured system that is not liable to sedimentation. It is shown that the use of CO as a reducing agent makes it possible to increase the yield of liquid hydrocarbons by a factor of 1.5. An increase in the syngas pressure has almost no effect on the yield of liquid hydrocarbons; however, it gives the possibility of enhancing the catalyst efficiency up to 700 g/(kg Fe · h) at 40 atm. In conditions of a three-phase system, gasoline-fraction hydrocarbons, half of which consist of olefins, are mostly formed on the nanosized catalyst.

Ethanol and diesel fuel from plant raw materials: A review

Data on various methods for the production of ethanol (bioethanol) and diesel fuel (biodiesel) from plant biomass and on the properties of raw materials in use are presented. Main trends in the development of processes for plant biomass conversion into bioethanol and biodiesel are considered.

Fischer-tropsch synthesis in a three-phase system over nanocatalysts (review)

The modern methods of preparation of nanoparticles of metals (cobalt and iron) and their oxides are described. The results of Fischer-Tropsch synthesis in a three-phase (gas-liquid-solid) system over iron and cobalt nanocatalysts are discussed. It is noted that in most cases, nanocatalysts exhibit a higher activity in comparison with conventional catalysts that are used for the liquid-phase synthesis. Under certain conditions, the efficiency of a nanocatalyst can achieve 5 kg/(kg cat h), which is an order of magnitude higher than that of conventional catalyst systems.

Products of the Fischer-Tropsch synthesis (A Review)

The composition of the products of hydrocarbon synthesis from carbon monoxide and hydrogen and also the composition and properties of individual fractions (commercial products) obtained by this method are considered. The reaction paths of the formation of different carbon-containing compounds (gaseous, liquid, and solid hydrocarbons) under the Fischer-Tropsch synthesis conditions and synthesis by-products (alcohols and CO2) and the possible directions of their secondary conversions are demonstrated.

Fischer-Tropsch process in a three-phase system over iron-cobalt catalyst nanoparticles in situ synthesized in a hydrocarbon medium

It has been shown that Fe-Co nanocatalysts in situ synthesized in a hydrocarbon medium with a Fe/Co weight ratio of 2–6 can mediate the Fischer-Tropsch synthesis in a three-phase system at a pressure of 20 atm, a temperature of 250–300°C, and a CO/H2 ratio of 1: 1. The introduction of CO leads to a significant increase in the total activity of the catalyst system (KCO reaches 85% at 300°C). However, gas evolution is enhanced and the highest yield of liquid products is as low as 74 g/m3 in this case. The introduction of K and Al into the Fe-Co catalysts and the optimization of the Fe/Co ratio make it possible to increase the yield of liquid products to 143 g/m3 (Fe/Co = 2.4) and achieve an efficiency of 337 g/(kg Me h). The Fe-Co nanocatalysts exhibit a high polymerizing activity (Schulz-Flory alpha is higher than 0.8). Hydrocarbons obtained over Fe-Co-K-Al catalysts contain more than 20% olefins. Their amount increases with the increasing Fe concentration in the sample. Oxygenates formed over these catalysts are composed of alcohols by over 90%, of which ethanol prevails (65–70%).

State-of-the-Art Processes for Manufacturing Synthetic Liquid Fuels via the Fischer-Tropsch Synthesis

Processes for manufacturing synthetic liquid fuels on the basis of the Fischer-Tropsch synthesis from alternative feedstock (natural gas, coal, biomass of various origins, etc.) are surveyed. State-of-the-art technology, companies that offer such processes, and the quality of products in comparison with their oil analogs, as well as economic features of the processes, are considered.

Fischer-Tropsch synthesis in a slurry reactor in the presence of nanosized cobalt catalysts synthesized in situ in a hydrocarbon medium

Fischer-Tropsch synthesis in a slurry reactor at a pressure of 20 atm and a temperature of 220–300°C in the presence of 100Co : 2Pd : (5–50)Al2O3 and 100Co : 2Pd : (20–50)ZrO2 (parts by weight) catalysts in situ synthesized in a hydrocarbon medium has been studied. The catalysts were prepared by the decomposition of cobalt salts and promoters in melted petroleum paraffin P-2 at 300°C and in situ reduced with hydrogen. It has been found that the nanocatalyst containing 20 parts by weight of ZrO2 exhibits the highest activity in the Fischer-Tropsch synthesis and provides the yield of liquid products of 70 g/m3 at a CO conversion of 80%.

Fischer-Tropsch synthesis in the presence∣ of cobalt-containing composite materials based on carbon

The Fischer-Tropsch synthesis in the presence of composite materials prepared by the IR pyrolysis of polyacrylonitrile (PAN) with cobalt salts immobilized on it was studied. The catalysts were small granules containing PAN carbonization products and to 80% cobalt metal particles of size 10–17 nm. The synthesis was performed in flow reactors with a fixed bed and a catalyst bed suspended in a liquid at 2–3 MPa and 200–310°C. It was established that the activity of the catalyst depends on the nature of the cobalt salt used, the temperature of IR pyrolysis, and the synthesis conditions. The catalyst prepared with the use of cobalt carbonate exhibited the greatest activity. The yield of liquid hydrocarbons on it reached ∼70 g/m3 at ∼60% selectivity. It was found that the test composite materials were characterized by an extremely high productivity of 2–5 kg (kg Co)−1 h−1.

Fischer-Tropsch synthesis catalysts as the core of the strategy for obtaining synthetic liquid fuels

The Fischer-Tropsch synthesis is a practically significant reaction catalyzed by Fe and Co, which are active at different H2: CO ratios of 0.5 and 2, respectively. For this reason, Fe-containing catalysts are preferentially used in coal-to-liquids (CTL) and biomass-to-liquids (BTL) processes, while Co-containing catalysts are preferred for the gas-to-liquids (GTL) technology. With the Fe catalysts, which are remarkable for their high CO2 formation selectivity, it is appropriate to carry out the carbon dioxide reforming of the feedstock.

Formation of alcohols on nanosized iron catalysts under Fischer-Tropsch synthesis conditions

Regularities of the alcohol formation in a three-phase system in the presence of the nanosized 100Fe: 8Al2O3: 3K2O (parts by weight) iron catalyst under the Fischer-Tropsch synthesis conditions have been determined. It has been found that the molecular-weight distribution of alcohols does not follow the Anderson-Schulz-Flory law. The principal product is ethanol; its proportion in the mixture can be as high as 78 wt %. It has been supposed that the formation of alcohols can follow the mechanism including the CO insertion in the metal-carbon bond. It has been shown that the highest ethanol yield (78 wt %) is obtained using 20 atm, 300°C, and H2/CO = 2.5 (mol/mol), an iron-containing catalyst charge in the reactor of 2 wt %.