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The pressure drop across the distributor signifies the total pressure drop and ensures desired fluidization in the fluidized bed. This study estimates the pressure drop requirements for 1.2 and 2.05 mm particles utilizing two distinct perforated type conical distributors with 154 and 302 orifices, respectively. The investigation was carried out in a cold flow condition. The pressure drop across the distributor was introduced in this investigation by filling bed material in the conical portion of the distributor. To estimate the bed pressure, a combined pressure drop of the conical distributor with and without bed material was approached. Explicitly, pressure drop requirements for the minimum fluidization and bubbling regimes have been focused on and presented in this work. In view of bed pressure, an attempt has been made to establish a relationship for pressure requirements across distributors. The integration and estimation of pressure drop across distributor with bed material in conical portion could be very beneficial in view of the fluidized bed. As the bed height increased, the pressure increased, but the pressure drop ratio decreased for the selected particles. The distributor features a higher number of orifices that demonstrate lower pressure requirements during fluidization and bubbling regimes. This study emphasizes the desired pressure requirements for the fluidized bed. [ABSTRACT FROM AUTHOR]

Information on comparative gasification reactivity of high temperature chars in CO2 with high ash coal (C), sawdust (SD) and rice husk (RH) under identical condition is important for clean energy development drive particularly in countries like India, where energy matrix is dominated by coal and introduction of larger quantity of biomass in energy‐mix is attracting global interests. Therefore, TGA‐studies on char‐gasification reactivity using CO2 as a gasifying agent were performed at temperatures 850–1000 °C. In case of coal and RH‐chars, CO2 reactivity found to increase with increasing the BET surface area and reverse trend was observed with SD‐chars. Both the biomass‐chars showed increased specific micro pore surface area with increasing char preparation temperature through t‐plot analysis, still keeping unusual behavior of CO2 reactivity of SD‐char unexplained. The estimations indicating the presence of catalytically active alkali and alkaline earth metals in substantial quantity is only important criteria found to explain the decreasing trend of gasification reactivity of SD‐char prepared at various temperatures despite the increase in surface area. Catalytic activity of the components decreases with the rise in char preparation temperature. Kinetic analysis reveal that activation energy values of SD‐chars varied in the range123–182 kJ mole−1, whereas those for coal‐ and RH‐chars remained in the range 204–214 kJ mole−1. [ABSTRACT FROM AUTHOR]

It is desirable to exploit biomass energy along with coal and petcoke through gasification, and understanding the differences between petroleum coke (petcoke), coal and biomass gasification behaviour becomes very essential. Consequently, present investigation compares gasification components of petcoke, sawdust and high ash coal with their physico-chemical properties under isothermal conditions in CO2 atmosphere in the temperature range of 1173–1623 K. Physico-chemical characterisation includes proximate and ultimate analyses, porous structure analysis by Brunauer-Emmett-Teller (BET) surface area from nitrogen (N2) adsorption isotherm, ash composition analysis and ash fusion temperature. The effects of temperature and nature of different solid fuels on gasification reactivity have been discussed. Gasification kinetics has been investigated using two nth-order kinetic models, such as homogeneous model (HM) and shrinking core model (SCM). Influence of diffusion resistance on gasification behaviour of different solid fuels is also reported. Thus, the present study will be helpful to realise the effects of high ash in gasification behaviour as well as in designing and modelling of the suitable gasifier and to establish optimum gasification conditions for petcoke, biomass and high ash coal. [ABSTRACT FROM AUTHOR]

Worldwide chemical industries are concerned towards pollution‐free and green processes. In this regard, alternative energy resource having minimal pollutant and toxins emission would be preferred. Jatropha curcas (JCO) is one of the important and alternative feedstock for biodiesel production. In the present work, JCO with higher (5.5%) free fatty acid (FFA) was used for transesterification using K–Mg composite catalyst. It found that 1:2 ratio of K/Mg was the best combination for efficient conversion of JCO to corresponding methyl esters. Physico‐chemical characterization of this novel catalyst exhibited improved surface area with adequate porosity as well as basicity helping its exceptional catalytic activity. Under optimum condition, 99.5% conversion was achieved using 10:1 ratio of methanol to JCO for 3 h at 70°C using 6 wt% of catalyst. This catalyst was truly heterogeneous in nature and almost retained its activity for subsequent re‐using for next five batches. The developed catalyst is highly efficient and greener in terms of lesser leaching behaviour and retaining the basic catalytic sites in the course of transesterification. The fuel properties of the biodiesel are fully complied with ASTM protocols; thus, research findings are significant to fulfil the demand of biodiesel in present scenario. [ABSTRACT FROM AUTHOR]

The Fluidization behavior of coal ash particles was studied to establish fluidization parameters in a cylindrical bubbling fluidized bed. A series of experiments were carried out with different sizes of irregular coal ash particles ranging from 1 mm to 3 mm at different bed heights at atmospheric pressure and room temperature (ca. 28 °C). Fluidization regimes of all selected coal ash particles were studied by varying flow rates of fluidization medium i.e., air. The change in bed height and pressure drop across the bed was carefully analyzed to see the effects of particle size and superficial gas velocity during fluidization. The minimum fluidization velocity (Umf), minimum bubbling velocity (Umb) and fluidization index for different sizes of ash particles in cold conditions were calculated. The validation of experimental values was supported by theoretical calculations. It was observed that the Umb is 1.5–1.8 times higher than the Umf at different bed heights (Hbed). No substantial deviation was found in Umf with the variations of Hbed at a particular mean particle diameter (dp). Finally, the fluidization index between 1.58 and 1.78 for coal ash particles of Geldart-D type (dp> 1000 µm) shows an ideal condition for fluidization. [ABSTRACT FROM AUTHOR]

In the present study, char samples of two biomasses and their blends with high ash Indian coal were prepared at 9000C and then gasified in the temperature range of 8500C to 10000C in CO2 atmosphere using thermogravimetric analyzer (TGA). It is observed that the char gasification reactivity of coal-biomass blend is lesser in comparison with the gasification reactivity of pure biomass. The effect of gasification temperature on reactivity as well as comparison between gasification of two pure biomasses and their blends with coal have been studied. The activation energy of biomass and their blends has also been discussed in this paper. The gasification reactivity and kinetic data developed from thermogravimetric analysis study may be useful for modelling and designing of suitable gasifier as per the available feedstocks. [ABSTRACT FROM AUTHOR]