Tao Kan

Liquid Fuels From Ethylene Tar by Two-stage Catalytic Hydroprocessing

Two-stage hydroprocessing of ethylene tar was performed on bench-scale equipment under typical reaction conditions of hydrogen pressure of 6 MPa, liquid hourly space velocity of 0.8 h–1, H2/oil volume ratio of 1,600, first-stage temperature of 360°C, and second-stage temperature of 380°C. Alumina-supported molybdenum-nickel (Mo-Ni) and tungsten-nickel (W-Ni) catalysts, which were prepared through combinational technologies of ultrasonic-assisted impregnation and temperature-programming, were filled in the first and second stages, respectively. Gasoline (≤180°C) and diesel (180–360°C) fractions separated from the produced oil were analyzed. Results showed that the ethylene tar can be considerably upgraded through two-stage catalytic hydroprocessing, and fuels with sulfur and nitrogen contents of less than 10 and 2 ppm, respectively, were obtained.

Effect of Potassium Addition on Coprecipitated Iron Catalysts for Fischer-Tropsch Synthesis Using Bio-oil-syngas

The effects of potassium addition and the potassium content on the activity and selectivity of coprecipitated iron catalyst for Fischer-Tropsch synthesis (FTS) were studied in a fixed bed reactor at 1.5 MPa, 300°C, and contact time (W/F) of 12.5 gcath/mol using the model bio-oil-syngas of H2/CO/CO2/N2 (62/8/25/5, vol%). It was found that potassium addition increases the catalyst activity for FTS and the reverse water gas shift reaction. Moreover, potassium increases the average molecular weight (chain length) of the hydrocarbon products. With the increase of potassium content, it was found that CH4 selectivity decreases and the selectivity of liquid phase products (C5+) increases. The characteristics of FTS catalysts with different potassium content were also investigated by various characterization measurements including X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller surface area. Based on experimental results, 100Fe/6Cu/16Al/6K (weight ratio) was selected as the optimal catalyst for FTS from bio-oil-syngas. The results indicate that the 100Fe/6Cu/16Al/6K catalyst is one of the most promising candidates to directly synthesize liquid bio-fuel using bio-oil-syngas.

Characterization of C12A7-O- Catalyst and Mechanism of Phenol Formation by Hydroxylation of Benzene

The benzene conversion and phenol selectivity from C6H6/O2/H2O over [Ca24Al28O64]4+4O(C12A7-O) catalyst were investigated using a flow reactor. The benzene conversion increases with the increase of temperature, and the phenol selectivity mainly depends on both reaction temperature and the composition of the mixtures. The changes of the catalyst structure before and after the reactions and the intermediates on the catalyst surface and in the bulk were investigated by XRD, EPR and FT-IR. The catalytic reactions do not cause any damage to the structure of the positively charged lattice framework C12A7-O, but part of the O and O2 species in the bulk of C12A7-O translate to OH after the reactions. The neutral species and anion intermediate were investigated by Q-MS and TOF-MS respectively. It is suggested that the active O and OH species played a key role in the process of phenol formation.

Risk Assessment and Control of Emissions from Ironmaking

Processing of raw materials to valuable products results in the formation of undesired compounds due to feedstock impurities and process inefficiencies. During the iron and steelmaking process, iron ore is converted to iron and steel at high temperatures using carbon energy sources. As the iron ore and carbon sources contain minor and trace element impurities and the combustion of carbon is incomplete, certain undesirable compounds may be formed that can be detrimental if emitted to the environment. These emissions can pose significant risks to humans and to the health of the ecosystem. This chapter outlines the various emissions associated with ironmaking, the risks these emissions pose to the environment and the technologies employed to minimise or eradicate the pollutants.

Influence of Temperature on Properties of Products from Steam Pyrolysis of Rice Husk in a Fluidized Bed

Fast steam pyrolysis of rice husk was performed in a fluidized bed reactor. The pyrolysis conditions of the feed rate of rice husk at 12 kg/h, the feed rate of steam at 9 kg/h, and the vapor residence time of 0.62 sec were kept constant, and the pyrolysis temperature was varied from 430 to 630°C to investigate its influences on properties of the produced gas, liquid bio-oil, and solid char. Results showed that the components in the gaseous product (including CO2, CO, CH4, H2, etc.) were evidently affected by the temperature. Fourier transform infrared analysis was employed to research into the changing trend of the organic groups existing in the produced chars and bio-oils. Furthermore, detailed components in the bio-oils obtained under different temperatures were determined by gas chromatography-mass spectrometry analysis.