Shrikant Madhusudan Nanoti

A comprehensive life cycle assessment (LCA) of Jatropha biodiesel production in India

A life cycle approach was adopted for energy, green house gas (GHG) emissions and renewability assessment for production of 1ton of Jatropha biodiesel. Allocation and displacement approaches were applied for life cycle inventory, process energy and process GHG emission attribution to co-products. The results of process energy and GHG emission analyses revealed that the amount of process energy consumption and GHG emission in the individual stages of the life cycle assessment (LCA) were a strong function of co-product handling and irrigation. The GHG emission reduction with respect to petroleum diesel for generating 1GJ energy varied from 40% to 107% and NER values from 1.4 to 8.0 depending upon the methodology used for energy and emission distribution between product and co-products as well as irrigation applied. However, GHG emission reduction values of 54 and 40 and NER (net energy ratio) values of 1.7 and 1.4 for irrigated and rain-fed scenarios, respectively indicate the eco-friendly nature and renewability of biodiesel even in the worst scenario where total life cycle inventory (LCI), process energy and GHG emission were allocated to biodiesel only.

Isobaric vapour—liquid equilibria of the systems: Benzene—triethylene glycol, toluene—triethylene glycol and benzene—N-methylpyrrolidone

Abstract Isobaric vapour—liquid equilibria have been determined at 101.325 kPa for three binary mixtures: benzene—triethylene glycol, toluene—triethylene glycol and benzene— N -methylpyrrolidone. The data have been correlated with reasonable accuracy using the NRTL, Wilson and UNIQUAC equations using a non-linear regression approach based on the maximum-likelihood principle.

Removal of refractory sulfur and aromatic compounds from straight run gas oil using solvent extraction

In the present study, extraction of sulfur and polyaromatic impurities from actual straight run gas oil (SRGO) containing 1.3 wt% sulfur was studied using various solvents such as acetonitrile, N,N-dimethylformamide, furfural, N,N-dimethylacetamide and dimethyl sulfoxide. Effects of water as antisolvent, extraction conditions and types of extraction operation (batch, single and multi-stage and continuous) have been studied. Performance of solvent extraction process, which is governed by the degree of sulfur removal (Dsr) and yield of extracted SRGO (ESRGO), has been evaluated in terms of a performance factor (Pf,α), which has been defined in terms of weight factor (0 < α < 1) as: Pf,α = αDsr + (1 − α) yield. DMF was found to be a better solvent in terms of Pf,α and regeneration ability. The possibility of utilization of extract as carbon black feed stock (CBFS) has also been discussed based upon the calculated bureau of mines correlation index (BMCI) values.

Extractive Desulfurization of Gas Oils: A Perspective Review for Use in Petroleum Refineries

Refineries process a number of gas oils such as straight run gas oil (SRGO), light cycle gas oil, coker gas oil and visbreaker gas oil for producing a common gas oil pool to be used as a transportation fuel. Considering stringent sulfur standards, new strategies and design modifications are being evaluated for desulfurization of these gas oils with minimum loss of oil during the desulfurization process. In this review, developments in solvent extractive desulfurization of gas oil have been discussed from both fundamental and applied point of views. Various performance indicators used for solvent evaluation/screening in computational and experimental studies are discussed. Particular emphasis has been given on latest developments in performance evaluation of organic and ionic liquid solvents for desulfurization of SRGO and other gas oils. Various possible designs of solvent recovery section to remove solvent from raffinate and extract phases for solvent recycling have been reviewed. Various potential options for the use of extract as high-quality secondary feedstock or co-products to improve the process economics have been reviewed from technical and economic thoughts. Finally, some research gaps are identified to work upon for stimulating the implementation of extractive desulfurization in industry.

Effect of gas oil composition on performance parameters of the extractive desulfurization process

Extractive desulfurization of synthetic and actual gas oil with various solvents was carried out to understand the fruitfulness of studies on solvent screening using synthetic carrier phases. Solvent extraction of various model sulfur compounds from two synthetic carrier phases of different composition was carried out using N,N-dimethylformamide (DMF) solvent to illustrate the effect of the sulfur compound molecular structure on its extractability and interaction with the carrier phase composition. Removal of sulfur compounds from the synthetic carrier phase followed the order: BT ≈ DBT > 4-methyl-DBT > 3-methyl BT ≈ 4,6-dimethyl-DBT > 2-N-octylthiophene ≫ 1-dodecanethiol. Thereafter, extraction of actual straight run gas oil (SRGO), cracked gas oil (CGO), and their mixtures was studied using DMF to understand the effect of their composition on extraction performance. Performance parameters such as yield of raffinate, degree of sulfur removal, distribution coefficient, and performance factor were found to be quite different for different gas oil streams. Thereafter, models were developed for correlating performance of extraction in terms of degree of sulfur removal (Dsr), yield (Y) of extracted gas oil with composition of gas oil and operating conditions. A performance factor (Pf,α) (defined as the summation of Dsr and Y with the weight factor (α) to Dsr) model was used to estimate the optimum operating conditions to maximize the extraction performance. Results indicate that the value of the weight factor (α) affects operating conditions, Dsr and Y, significantly and should be chosen with utmost care in light of downstream process capabilities and overall process economics.

Liquid-liquid equilibrium in the toluene-methyl ethyl ketone-water system

Abstract For the toluene-methyl ethyl ketone-water system the liquid-liquid equilibrium tie-line data have been determined at 40 and 0°C and the binodal curve for this system has been determined at 40, 0 and −10°C. The tie-line data at 40 and 0°C could be correlated with good accuracy using NRTL and UNIQUAC model equations.

Techno-economic evaluation of top, middle, and bottom divided wall column configurations for benzene, toluene, and xylene processing in aromatic production plant

ABSTRACT Divided wall column (DWC) configurations were simulated and optimized for five different feed’s compositions to demonstrate the effect of feed composition and location of dividing wall in DWC in optimum operating conditions, energy requirement, operating, capital and total annualized cost (TAC) to produce market-grade benzene, toluene, and xylene. Operating conditions and cost for each DWC strongly depend on feed composition. Middle DWC (M-DWC) requires significantly lower energy compared with top and bottom DWCs except for feed dominated with xylene where energy requirement is comparable in studied configurations and M-DWC seems the best for ternary mixture separation.

ISOBARIC VAPOUR-LIQUID EQUILIBRIA FOR THE TERNARY MIXTURE METHYL ETHYL KETONE-WATER-TOLUENE

Abstract The vapourliquid equilibrium was measured for methyl ethyl ketonewatertoluene ternary in the miscible region at 101.325 kPa pressure. The miscible liquid-phase compositions were chosen from the ternary solubility curve determined experimentally at 40°C. The experimental ternary vapour-phase compositions have been compared with values calculated by NRTL, modified UNIQUAC and UNIFAC model equations using binary data available in the literature.