• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.297-302
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• 2018

Bead type and hollow fiber type catalyst (HFC, Hollow Fiber type Catalyst) was prepared by $La_{0.1}Sr_{0.9}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF1928) perovskite powder catalyst which showed excellent methane complete oxidation characteristics through previous studies. The HFC have a cylindrical shape with an empty interior, and pores can be formed through Phase inversion method so the specific surface area can be remarkably improved. In the case of the bead type catalyst prepared by adding Methyl Cellulose (MC), $SrCO_3$ was produced in addition to the original catalyst composition of LSCF1928 due to the reaction of $CO_2$ emitted from MC and Sr of the catalyst. In the case of the HFC, a single phase perovskite structure was obtained without impurities. The HFC calcined at $700{\sim}900^{\circ}C$ showed pore structure of finger-sponge-finger structure, and 99.9% oxygen conversion rate was achieved through complete oxidation of methane at $475^{\circ}C$. Air gap and spinning pressure condition were changed to control the HFC pore. 2 cm air gap and 7 bar spinning pressure showed the best catalytic performance and achieved oxygen conversion rates of more than 70.65%, 93.01%, and 99.99% at $425^{\circ}C$, $450^{\circ}C$ and $475^{\circ}C$, respectively.

• Fibers and Polymers
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• v.1 no.2
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• pp.97-102
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• 2000

Pitch precursors were synthesized from coal tar(CT) and pyrolysis fuel oil(PFO, petroleum residue oil) at relatively low temperature of $250^{\circ}$, in the presence of horontrifluorideidiethyletherate complex(BFDE) as a catalyst and nitrobenzene(NB) as a co-catalyst. The softening point, nitrogen content and carbon yield increased with an increase of concentration of NB. The pitch precursors with good spinnability were prepared by removing the volatile components through $N_2$ blowing. The precursor pitches were spun through a circular nozzle, stabilized at $310^{\circ}$ and finally carbonized at $1000^{\circ}$. The optically anisotropic structure formed at the absence of NB was changed into isotropic structure, showing a decrease in size of the flow domain. The hollow carbon fiber could be prepared in the process of stabilization. The results proposed that the morphology of carbon materials could be controlled by changing the concentration of catalyst and/or co-catalyst and/or stabilization condition that affect on the mobility of molecules during carbonization.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.774-780
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• 2019

An efficient Pd-coated $La_{0.1}Sr_{0.9}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF-1928) catalyst for total oxidation of methane under landfill gas at low tmeperature has been developed. Synergism was observed between Pd coating and LSCF-1928 substrate. When Pd coating on LSCF-1928, we used electroless plating method and conformed characteristic of catalyst through TPR(Temperature Programmed Reduction) analysis, XRD(X-ray Diffraction) analysis, SEM(Scanning Electron Microscope). The results demonstrated that the Pd coated LSCF-1928 catalysts showed higher performance than non-Pd LSCF-1928. Pd coated LSCF-1928 had low total oxidation temperature of methane (< $475^{\circ}C$) which is lower than total oxidation temperature of methane about non-Pd LSCF-1928 catalysts (= $475^{\circ}C$). Also, $O_2$ conversion rate was higher than non-Pd LSCF-1928 at same temperature.