Economic appraisal of supercritical fluid extraction of refined cashew nut shell liquid

This manuscript summarises the techno-economic feasibility of refined cashew nut shell liquid (CNSL). A simple mass transfer based mathematical model for the yield prediction is presented. The process parameters and extraction time for maximum profit and purity of the product were optimized. The optimum extraction time for maximum profit and purity was found to be 0.9 h at 300 bar and 323 K. The influence of the different costs, such as fixed cost, raw material cost, labor cost, utility cost, etc. on profit and cost of production of the extract is also presented.© Elsevie

A Process Model for Underground Coal Gasification: Part-II Growth of Outflow Channel

Underground Coal Gasification is a process of gasifying coal in-situ to produce syn-gas. The gas thus produced, passes through the outflow channel that leads to the production well. As explained in part-I of this paper (Samdani et al., 2014), cavity growth between injection and production wells happens in two distinct phases. This paper presents an unsteady state model for cavity growth and gas production in phase-II wherein, the growth occurs mostly in horizontal direction towards the production well through the outflow channel. This phase of UCG lasts much longer than phase-I, in which growth takes place in vertical direction till the cavity hits the overburden. In the model for phase-II, the outflow channel is divided in small sections along its length and each section includes three subzones i.e. rubble zone, void zone and roof at the top. A compartment model is developed to reduce the complexity caused by non-ideal flow patterns and changing sizes of different subzones inside the outflow channel. The subzones and the sections are linked appropriately, for mass and energy flow, to give overall performance during Phase-II of UCG. The proposed approach combines chemical reactions, heat and mass transfer effects, spalling characteristic and complex flow patterns to achieve meaningful results. In all, seven gas species, three solid species and eleven reactions are included. The simulation results such as variation in solid density, dynamics of different zones, exit gas quality are presented. The model is validated by comparing the predicted exit gas quality and that observed during similar laboratory scale experiments. Finally the results are also compared with field scale experiments. This model along with the Phase-I model provides a complete modeling solution for UCG process.Oil and Natural Gas Corporation Limite

Synthesis of Biodiesel from Vegetable Oil Using Supported Metal Oxide Catalysts

Biodiesel is known for its less polluting, renewable, and biodegradable properties. It is conventionally produced by the alkali-catalyzed transesterification of triglycerides. The use of a heterogeneous catalyst can make the production process cost-effective and environmentally friendly. In this work, we evaluated two catalysts, ZnO/zeolite and PbO/zeolite, for the synthesis of biodiesel using jatropha oil as a feedstock. Both catalysts exhibit reasonably good activity for the reaction of interest and are reusable under the reaction conditions. The leaching of metal ions during the course of the reaction is minimized by using zeolite as a support. The catalysts were characterized by X-ray diffraction, N₂ adsorption, transmission electron microscopy, scanning electron microscopy, and temperature-programmed desorption/temperature-programmed reduction. The PbO/zeolite catalyst performed better than the ZnO/zeolite catalyst when sunflower oil, which is free of fatty acids, was used as the feedstock. However, ZnO/zeolite was more active when jatropha oil, which contains substantial amounts of free fatty acids (>10% w/w), was used as the feedstock

Esterification of Oleic Acid with Glycerol in the Presence of Supported Zinc Oxide as Catalyst

The work deals with development of a new catalyst ZnO/zeolite and its performance evaluation for the industrially important reaction of esterification of oleic acid with glycerol. It is a reaction that takes place in liquid–liquid mode due to partial miscibility of glycerol and oleic acid. The reaction kinetics and product distribution over the developed catalyst are investigated under different conditions. The effects of different parameters such as catalyst loading, mole ratio, and temperature are studied. Higher temperatures and simultaneous water removal increase the reaction rate significantly. It is interesting to note that the selectivity toward monoglyceride for a given conversion remains unaffected with respect to temperature and mole ratio. A simplified kinetic model, that considers mono- and diesterification as a combination of series and parallel irreversible reactions, is proposed to explain the kinetic data

Small-Scale Ammonia Production from Biomass: A Techno-Enviro-Economic Perspective

Ammonia production has traditionally been based on large-scale plants. The thrust toward large-scale production to gain economic advantages has overshadowed the benefits that could be derived from small-scale production plants. Additionally, the ammonia industry consumes a major chunk of global fossil fuels, which also burdens the planet with greenhouse gases. To effectively counter these issues, this study investigates the production of ammonia from biomass. Processes based on biomass plants are usually small-scale and are limited by biomass supply. To ensure sustainable ammonia production, this study tries to highlight the techno-economic advantages that result from small-scale ammonia plants based on biomass feedstock. This paper proposes a new process that takes inputs from a relatively old, natural gas based process (leading concept ammonia) specifically designed for small-scale ammonia manufacture and couples it with a recently developed dual fluidized bed technology for biomass feedstock. Two different flowsheet configurations are simulated rigorously and compared to gain a better understanding of the process. The flowsheets are optimized, and energy integration is performed to provide a wider insight. The life cycle assessment calculations that are carried out using ASPEN Plus simulation results and ecoinvent databases predict a CO₂ emissions reduction of 54–68% when compared to conventional ammonia plants