Hydrogen or syn gas production from glycerol using pyrolysis and steam gasification processes

Glycerol is a waste by-product obtained during the production of biodiesel. Biodiesel is one of the alternative fuels used to meet our energy requirements and also carbon dioxide emission is much lesser when compared to regular diesel fuel. Biodiesel and glycerol are produced from the transesterification of vegetable oils and fats with alcohol in the presence of a catalyst. About 10 wt% of vegetable oil is converted into glycerol during the transesterification process. An increase in biodiesel production would decrease the world market price of glycerol. The objective of this work is to produce value added products such as hydrogen or syn gas and medium heating value gas from waste glycerol using pyrolysis and steam gasification processes. Pyrolysis and steam gasification of glycerol reactions was carried out in an Inconel®, tubular, fixed bed down-flow reactor at atmospheric pressure. The effects of carrier gas flow rate (30mL/min-70mL/min), temperature (650oC-800oC) and different particle diameter of different packing material (quartz - 0.21-0.35mm to 3-4mm; silicon carbide – 0.15 to 1mm; Ottawa sand – 0.21-0.35mm to 1.0-1.15mm) on the product yield, product gas volume, composition and calorific value were studied for the pyrolysis reactions. An increase in carrier gas flow rate did not have a significant effect on syn gas production at 800oC with quartz chips diameter of 3-4mm. However, total gas yield increased from 65 to 72wt% and liquid yield decreased from 30.7 to 19.3wt% when carrier gas flow rate decreased from 70 to 30mL/min. An increase in reaction temperature, increased the gas product yield from 27.5 to 68wt% and hydrogen yield from 17 to 48.6mol%. Also, syn gas production increased from 70 to 93 mol%. A change in particle size of the packing material had a significant increase in the gas yield and hydrogen gas composition. Therefore, pyrolysis reaction at 800oC, 50mL/min of nitrogen and quartz particle diameter of 0.21-0.35mm were optimum reaction parameter values that maximise the gas product yield (71wt%), hydrogen yield (55.4mol%), syn gas yield (93mol%) and volume of product gas (1.32L/g of glycerol). The net energy recovered at this condition was 111.18 kJ/mol of glycerol fed. However, the maximum heating value of product gas (21.35 MJ/m3) was obtained at 650oC, 50mL/min of nitrogen and with a quartz packing with particle diameter of 3-4mm. The steam gasification of glycerol was carried out at 800oC, with two different packing materials (0.21-0.35mm diameter of quartz and 0.15mm of silicon carbide) by changing the steam to glycerol weight ratio from 0:100 to 50:50. The addition of steam to glycerol increased the hydrogen yield from 55.4 to 64mol% and volume of the product gas from 1.32L/g for pyrolysis to 1.71L/g of glycerol. When a steam to glycerol weight ratio of 50:50 used for the gasification reaction, the glycerol was completely converted to gas and char. Optimum conditions to maximize the volume of the product gas (1.71L/g), gas yield of 94wt% and hydrogen yield of 58mol% were 800oC, 0.21-0.35mm diameter of quartz as a packing material and steam to glycerol weight ratio of 50:50. Syn gas yield and calorific value of the product gas at this condition was 92mol% and 13.5MJ/m3, respectively. The net energy recovered at this condition was 117.19 kJ/mol of glycerol fed. The steam gasification of crude glycerol was carried out at 800oC, quartz size of 0.21-0.35mm as a packing material over the range of steam to crude glycerol weight ratio from 7.5:92.5 to 50:50. Gasification reaction with steam to glycerol weight ratio of 50:50 was the optimum condition to produce high yield of product gas (91.1wt%), volume of gas (1.57L/g of glycerol and methanol), hydrogen (59.1mol%) and syn gas (79.1mol%). However, the calorific value of the product gas did not change significantly by increasing the steam to glycerol weight ratio

Clarification note on taxonomic identification of Atergatis ocyroe (Herbst, 1801) (Crustacea: Decapoda: Xanthidae): New distributional record from the Port Blair coast, Andaman & Nicobar Islands, India

488-491A survey was conducted to study the distribution of brachyuran crabs along the coast of south Andaman Island during 2015-2018. The investigation confirmed the occurrence of Atergatis ocyroe (Herbst, 1801) from the Port Blair Coast of Andaman & Nicobar Islands, India. From a comprehensive study of standard literature, it was evident that A. ocyroe was misidentified as A. floridus and these two species do not co-exist in the same geographical area. Hence, the existence of A. floridus in Andaman and Nicobar Islands is doubtful. The confirmed distributional record of A. ocyroe across the Indian Ocean is provided and discussed with its taxonomy, and detailed description along with photograph and line diagram is provided in this study

A Prediction Of Welding Process Control Variables By Prediction Of Weld Bead Geometry Using Factorial Design Approach

Plasma Enhanced Shielded Metal Arc Welding (PESMAW) is a modified version of the age old manual metal are welding (MMA) where the cellulose based flux coated solid wires are replaced by tubular low hydrogen flux coated electrodes. PESMAW process is aimed to eliminate the usage of cellulose in the electrode coating so as to save some trees and hence make the welding process partially green. The high heat content of the cellulose supported arc is achieved by controlled supply of auxiliary plasma gas through the tubular wire directed into the arc. This paper discusses the influence of the welding process parameters to the weld bead characteristics of weldments made by PESMAW process using mild steel as base metal. Two level fractional factorial design was adopted to investigate and quantify the direct and interactive effects of four major control parameters. “Bend on plate” technique was used to lay weldments and bead geometry was measured using standard metallurgical procedures. Statistical models were made from the obtained results and were analyzed and tested by using analysis of variance technique and students’t’ test. The main and interactive effects of control parameters were studied and presented in graphical form

Effect of cyclonic storm Vardah on the community structure and ecosystem functioning of macrobenthic fauna in the intertidal region of South Andaman Islands

An investigation was carried out to understand the effect of a cyclone Vardah on the functioning of macrobenthos. The assessment was accomplished by comparing before cyclone (BC) and after cyclone (AC) data of macrobenthos. Additionally, temporal changes in the faunal assemblages were evident through multivariate techniques. Five distinguished assemblages could be noticed through the Bray–Curtis similarity representing different phases of the cyclone. The cyclonic effect also resulted in the recruitment of some macrobenthic species and the loss of a few during the study period. Biological trait analysis identified subsurface deposit feeders, upward and downward conveyers, Ecological Group IV, mid-mobile macrobenthos and size class of 2–4 cm as the important groups that dominated the functioning of the macrobenthic community immediately after the cyclone. The resilience and recruitment of macrobenthos were explained using functional redundancy

Low-Voltage SEM of Natural Plant Fibers: Microstructure Properties (Surface and Cross-Section) and their Link to the Tensile Properties

In this study, the microstructure of different natural plant fibers (flax, jute, ramie, and sisal fibers) were characterized by using low-voltage Scanning Electron Microscopy (LV-SEM). The LV-SEM observations indicated that jute and sisal fibers exhibit less variation in terms of the fiber cross-sectional area, internal lumen shape and size, and cell wall thickness in comparison to flax and ramie fibers. We find that this is also reflected in the tensile properties of the fibers. The tensile properties of single ramie fibers and their fracture behavior was investigated in detail. The stress-strain behavior showed two distinctive regimes. For linear curves, the tensile strength varies from 648-1086 MPa whereas nonlinear curves result in much lower values (177-452) MPa. This variation was linked to differences in the microstructure of the fibers. The LV-SEM of the tensile fracture surfaces of ramie fibers revealed details on the cell wall structure and its fracture behavior under tensile load. Moreover, the SEM images confirm that the collapse of the primary cell wall generally leads to a non-linear stress-strain curve for single ramie fibers

Hydrolysis of aluminium metal, synthesis of nano alumina and sol-gel processing of monoliths

High purity alumina is usually prepared using various intermediate aluminium compounds such as aluminium nitrate, aluminium alkoxides etc., as precursors. In fact the above mentioned intermediate aluminium compounds themselves are produced from aluminium metal. The present investigation is concerned with examining the feasibility of using aluminium hydroxides prepared by hydrolyzing aluminium metal, for sol gel processing. The study assumes added significance in view of the claims of Alcoa that it is possible to produce high purity aluminium metal in large quantities economically. During the present investigation sols were prepared by using various hydroxides, ie., bayerite, gibbsite and boehmite. Sol gel transition was observed only in the case of boehmite sol and this was gelated by either forced gelation method to prepare powder or controlled gelation method to prepare monoliths. Transparent Xerogels (boehmite) could be prepared by controlled gelation method but the presence of a thin layer of bayerite often resulted in translucency. Crack free monoliths could be prepared by heating the xerogels at a low heating rate(< 1 degrees C/min). It was found that sol gel processed boehmite transformed to alpha alumina at a relatively lower temperature (similar to 1080 degrees C ) than the as prepared boehmite which transformed at about 1200 degrees C

Habitat heterogeneity determines structural properties of intertidal gastropod assemblages in a pristine tropical island ecosystem

846-855Community dynamics of gastropods were studied from four selected intertidal locations along an18km long coastal stretch on the east coast of south Andaman Islands. A total of 71 taxa belonging to 17 families and 3 orders were identified. While Nassariidae (31.15%) made maximal contribution to faunal abundance, Muricidae (11 species) and Conidae (9 species) were mainly responsible for changes in diversity patterns. In general, abundance and diversity exhibited a reversing trend. Most diverse area (H’=1.816±0.49 and d= 2.68±0.97) was found in the middle of the southeast coastal stretch. Multivariate analysis revealed the presence of location-specific gastropod assemblages spearheaded by Nassarius spp. and Nerita spp. The results yielded a potential positive correlation between locations and gastropod diversity along the entire coastal stretch

Hydrolysis of aluminium metal and sol-gel processing of nano alumina

Aluminium metal has been hydrolysed at 100 degreesC to synthesize boehmite. Gelatinous and dry boehmite were used to prepare stable sol. In the case of gelatinous boehmite, sol was prepared by peptizing and in the case of dry boehmite an ultrasonic bath was used to prepare the sol. Gelation was carried out by heating on a hot plate, which resulted in sol-gel processed powder. For sol-gel processed boehmite the theta --> alpha transformation occurred at 1078 degreesC and for the as prepared boehmite the same occurred at 1206 degreesC. Sol-gel processed powder could be transformed to alpha alumina completely, when calcined at 1000 degreesC for 1 h. (C) 200