Catalyst In Fluidized Bed Reactor Research Articles

Temperature and dilution effects on MTO process with a SAPO-34-based catalyst in fluidized bed reactor

Conversion of methanol to light olefins (MTO) using SAPO-34 molecular-sieve as the reaction catalyst was studied in a fluidized bed reactor within the temperature range of 400–550 °C by 50 °C increments and under 50, 66.6 and 90 vol% of methanol in the feed, diluted with water or an inert. SAPO-34-based catalyst was prepared by agglomeration with clay and alumina to allow proper fluidization. Catalytic results show the highest olefin yield for 500 °C and a reduction in catalyst deactivation for 1:1 methanol:water molar ration in the feed.

Experimental study on in-situ denitration using catalyst in fluidized bed reactor

This work proposed a process route for in-situ denitration in circulating fluidized bed (CFB) reactor through adding catalyst, and the feasibility has been verified through a bubbling FB reactor, a 6 kWth FB combustor and a 75 t/h CFB boiler. The effect of bed temperature, atmosphere and addition amount of catalyst on NO conversion rate were studied in the bubbling FB reactor. It was found that the increasing bed temperature, CO concentration and addition amount of catalyst can enhance the conversion efficiency of NO, and increasing concentration of SO2 and H2O have the opposite effect. The results from 20 h test suggested that a high SO2 and H2O atmosphere did not deactivate the catalyst. The continuous combustion experiments on a 6 kWth FB combustor showed that the catalyst addition not only can significant reduce NOx emission (>20%, even under conditions of low oxygen concentration and low ratio of primary air), but also does not have any adverse effect on the combustion characteristics. Similar results were also obtained from the 75 t/h CFB boiler. It was also found in the industrial scale tests that the addition of catalysts combined with the use of SNCR system would achieve better denitration effects.

Optimization of a fluidized bed reactor for methane decomposition over Fe/Al2O3 catalysts: Activity and regeneration studies

Catalytic methane decomposition was investigated over 40 wt% Fe/Al2O3 catalyst in fluidized bed reactor (FLBR). After optimization of FLBR conditions in terms of catalyst bulk density, particle size, minimum fluidization velocity, and the catalyst bed height, the catalyst activity and stability tests were conducted by comparison with a fixed bed reactor (FBR). Although a similar stable methane conversion was obtained over both reactors, the pressure drop during 35 min operation of FBR was 9 times higher than that of FLBR, which indicated the possibility of continuous operation of methane decomposition process over FLBR. Further, the influence of the space velocity, feed dilution and regeneration on catalysts reactivity was studied in FLBR to conclude that a reaction condition of 12 L/gcat∙h, feed of 20%H2–80%CH4 and CO2-regeneration of deactivated catalysts may be favourable for operating methane decomposition in FLBR continually and effectively to provide stable hydrogen.

Magnetic field acceleration of CO2 reforming of methane over novel hierarchical Co/MgO catalyst in fluidized bed reactor

Magnetic field acceleration of CO2 reforming of methane over a novel hierarchical Co/MgO catalyst in fluidized bed reactor is reported. The hierarchical Co/MgO catalyst shows good fluidization quality and is suitable for efficient CO2-CH4 reforming in fluidized-bed reactor. Compared to the conventional fluidized bed reactor (CFB), the hierarchical Co/MgO catalyst shows better conversions of CO2 and CH4, higher turnover rate, and higher resistance to coke deposition in the magnetic assisted fluidized bed (MFB) reactor. The enhancement of the magnetic field for the CO2 reforming of methane originates from the high breaking and coalescing frequency of clusters in the MFB reactor, thus improved the gas-solid contact efficiency. The approach of improving the catalytic activity by coupling of hierarchical Co/MgO particles and magnetic fluidized-bed is effective for the syngas production from the perspective of matching catalysts with fluidized-bed reactors.

Production of synthetic natural gas by CO methanation over Ni/Al2O3 catalyst in fluidized bed reactor

In order to obtain the reaction characteristics, CO methanation process is numerically investigated in fluidized bed catalytic reactor over Ni/Al2O3 catalyst. The catalysts flow behavior is analyzed, which has significant effect on the activity of catalysts. The influences of operation parameter on CO conversion and CH4 yield are evaluated. The inventory of catalysts and superficial gas velocity will not influence the output of methane but the reaction rates. Meanwhile, the performance of water-gas shift reaction on CH4 yield is taken consideration during reactions.

Comparative study of MTO kinetics over SAPO-34 catalyst in fixed and fluidized bed reactors

In this work, a comparative study on methanol to olefins (MTO) kinetics in fixed and fluidized bed reactors was conducted. Based on the analysis of experimental observations, a modeling approach that can be used to simulate both reactor configurations was proposed. The coke deposition was shown responsible for the difference of product selectivities for these two reactor configurations. In a fluidized bed reactor, the distribution of the coke deposition is spatially uniform, and evolves with time on stream. However, the coke deposition shows a distribution along the bed height in a fixed bed reactor, and olefins conversions were taken into consideration to account for the selectivity changes with time on stream. With the proposed model, we established a linkage between fixed bed reactors and fluidized bed reactors through coke deposition. By use of this model, it is possible to predict the performance of MTO reaction over SAPO-34 catalyst in fluidized bed reactor with experimental data obtained in fixed bed reactor, or verse vice.

The Development of Ni/Dolomite Catalyst in Simultaneous Biomass Gasification and Reforming in Fluidized Bed

Simultaneous gasification and steam reforming of t he biomass on Ni/dolomite catalyst in fluidized bed reactor were studied in the gaseous p roduction in the one stage reactor. Problem statement: The parameters such as temperature, steam flow rat e, biomass feed rate, gas flow rate for fluidization, oxygen flow rate and catalyst types w ere studied to produce the high gaseous products including tar elimination. Approach: The temperature at 780°C, steam flow rate of 222 mmoL h -1 , gas flow rate for fluidization 450 mL min -1 and oxygen input 50 mL min -1 were found to be the suitable conditions. The Ni/Dolomite and the developed Ni/Dolomite were studied about their performance. Results: It was confirmed that Ni/Dolomite and newly developed Ni-WO 3/Dolomite show high performance in biomass gasification. Conclusion/Recommendations: It was claimed that Ni/Dolomite catalyst was the effective and give bes t performance for tar cracking. Newly developed Ni-WO 3/Dolomite catalyst was investigated to resist sulfu r nd coking. Three types of catalyst were used in the biomass gasification, which are Ni/Dolo mite, Ni/Dolomite+Silica binder and Ni- WO 3/Dolomite. From the XRD analysis, structures of typ e 1 (Ni/dolomite) and type 2 (Ni/Dolomite+Silica binder) were similar which were in CaCO 3, MgNiO 2, NiO and MgO forms. Type 3 (Ni-WO 3/Dolomite) was CaWO 4, MgNiO 2, NiO and MgO forms. When the catalytic gasification was operated, newly Ni- WO 3/Dolomite catalyst was the best catalyst for bamboo and palm shell biomasses, which could produce the high carbon monoxide and hydrogen but low methane and carbon dioxide were found. Carbon deposition on catalyst was around 0.37 mg according to the TG analysis.

Catalytic conversion of methane and CO 2 to synthesis gas over a La 2O 3-modified SiO 2 supported Ni catalyst in fluidized-bed reactor

In this contribution, a commercial spherical SiO 2 was modified with different amounts of La 2O 3, and used as the support of Ni catalysts for autothermal reforming of methane in a fluidized-bed reactor. Nitrogen adsorption, XRD and H 2-TPR analysis indicated that La 2O 3-modified SiO 2 had higher surface area, strengthened interaction between Ni and support, and improved dispersion of Ni. CO 2-TPD found that La 2O 3 increased the alkalescence of SiO 2 and improved the activation of CO 2. Coking reaction (via both temperature-programmed surface reaction of CH 4 (CH 4-TPSR) and pulse decomposition of CH 4) disclosed that La 2O 3 reduced the dehydrogenation ability of Ni. CO 2-TPO, O 2-TPO (followed after CH 4-TPSR) confirmed that only part amount of carbon species derived from methane decomposition could be removed by CO 2, and O 2 in feed played a crucial role for the gasification of the inactive surface carbons. Ni/ xLa 2O 3-SiO 2 ( x = 10, 15, 30) possessed high activity and excellent stability for autothermal reforming of methane in a fluidized-bed reactor.

Decoloration and mineralization of yeast wastewater by using Ce-Fe/Al2O3 as heterogeneous photo-Fenton catalyst

Decoloration and mineralization of yeast wastewater were investigated by using Ce-Fe/Al2O3 as a heterogeneous photo-Fenton catalyst in fluidized bed reactor in order to solve the problem of yeast wastewater discharge. The experimental results were assessed in terms of total organic carbon(TOC) reduction. The operational and reaction conditions affecting the efficiencies of TOC removal such as initial pH value, H2O2 concentration, catalyst loading and UV power were studied. The results show that TOC is reduced from 347.6 mg/L to 10.8 mg/L, color is changed from 500 units to 0 under the conditions as follows: initial pH value 6.0, H2O2 concentration of 1.000 g/L, catalyst loading of 5 g/L, reaction duration of 120 min and reaction temperature of 30 °C. The irradiated Ce-Fe/Al2O3 catalyst was complexed with 1,10-phenanthroline and then it was subjected to Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy to confirm the formation of Fe(II) in the solid state. Heterogeneous photo-Fenton reaction proves to be effective for the treatment of yeast wastewater.