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Highlights: [•] Stability of metal contaminated biodiesel blend has been checked. [•] Effectiveness of different antioxidants has also been checked. [•] Biodiesel blends with diesel have shown the better oxidation stability. [•] Effect of metals on the oxidation stability of biodiesel has found catalytic. [Copyright &y& Elsevier]

Highlights: [•] Present paper reports the storage stability studies of Jatropha curcas biodiesel (JCB). [•] Various correlations were developed for storage stability. [•] These correlations can be used to predict the amount of antioxidants required for stabilizing the biodiesel. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present study is to investigate engine performance and the exhaust emissions of a diesel engine using oxidatively stabilized biodiesel. Biodiesel fuel used in the study was prepared from Jatropha curcas oil. Different samples with various metal contaminants, generally available in the metallurgy of the containers are oxidatively stabilized with antioxidant (PY) according to EN 14112. The brake specific fuel consumption (BSFC) of biodiesel fuel with and without antioxidant is more than that of petro-diesel fuel. The BSFC of biodiesel fuel with antioxidants is lesser than that of biodiesel fuel without antioxidants, but no specific trends were detected according to the type of metal content and amount of antioxidants. The combustion characteristics and exhaust emissions in diesel engine were not influenced very much by the addition of antioxidants in biodiesel fuel. Also performance and emission characteristics of unstablized biodiesel and stabilized biodiesel (stabilized for 6months) are measured with respect to time. [Copyright &y& Elsevier]

Abstract: Biodiesel, an ecofriendly and renewable fuel substitute for diesel has been receiving the attention of researchers around the world. Due to heavy import of edible oil, the production of biodiesel from edible oil resources in India is not advisable. Therefore it is necessary to explore non-edible seed oils, like Jatropha curcas (J. curcas) and Pongamia for biodiesel production. The oxidation stability of biodiesel from J. curcas oil (JCO) is very poor and therefore an idea is given to increase the oxidation stability of biodiesel by blending it with petro-diesel. J. curcas biodiesel (JCB), when blended with petro diesel leads to a composition having efficient and improved oxidation stability. The results have shown that blending of JCB with diesel with less than 20% (v/v) would not need any antioxidants but at the same time, need large storage space. Similarly, if the amount of diesel is decreased in the blend, it will require the addition of antioxidant but in lesser amount compared to pure JCB. For the purpose five antioxidants were used namely butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), propyl gallate (PG), and pyrogallol (PY). A B30 blend (30% JCB in the blend of JCB and petro-diesel) has been tested for the same purpose. PY is found to be the best antioxidant among all five antioxidants used. The optimum amount of antioxidant (PY) for pure biodiesel tested for the present experiment is around 100ppm while it is around 50ppm for B30 blend to maintain the international specification of oxidation stability. [Copyright &y& Elsevier]

Abstract: The present paper reports the results of the study of the effect of metal contaminants on the storage stability of Jatropha curcas biodiesel (JCB) with and without antioxidants. Taking 1,2,3 -Trihydroxybenzene/Pyrogallol (PY) as the most effective antioxidant based on the earlier work of the authors, JCB was mixed with different transition metals – Fe, Ni, Mn, Co and Cu in different concentrations. Induction period (IP) was measured using Rancimat method (EN 14112) as the stability parameter. Based on results, several correlations were developed for assessing the storage stability in terms of IP as a function of antioxidant, metal concentration and storage time. For the purpose of design of experiment, response surface methodology (RSM) has been used. From the experiments it is found that if metal concentration is 0 then, 200 g m−3 of PY is sufficient to make biodiesel stable for 6 months. If metal (Fe) concentration is 2 g m−3 or more, then 800 g m−3 PY is sufficient to make biodiesel stable for 5.5 months. The value of storage time for Ni, Mn, Co and Cu contaminated JCB is found as 3.62, 3.24, 2.76 and 2.07 months respectively if metal and antioxidants concentration is same in all the cases. The models developed by RSM shall be highly useful for predicting the optimum antioxidant concentration to achieve maximum storage stability of JCB as well as biodiesel from other resources under the conditions set for 3 factors (antioxidant concentration, metal concentration and time). [Copyright &y& Elsevier]

Abstract: The objective of this work was to study the long term storage stability of JCB (Jatropha curcas biodiesel). For the objective JCB was mixed with PY (Pyrogallol) and different metal contaminants. JCB samples were stored for 6 months in open air exposed to sunlight. Different properties were checked with respect to time. It was found that stability of fresh JCB was not acceptable as per EN 14214. When PY was mixed with JCB, it stability increased and 200 ppm of PY was sufficient to make fresh and pure JCB stable for almost 6 months. Viscosity (n), PV (peroxide value) and AV (acid value) increased with respect to time. Unsaturated fatty acid composition was also checked with respect to time. From the experiment it was clear that as oxidation deterioration advanced, linoleic and linolenic acid methyl esters decreased and the fraction of oleic acid methyl became relatively high with respect to storage time. [Copyright &y& Elsevier]

Abstract: The present paper deals with the study on the effect of metal contaminants on the oxidation stability of Jatropha curcas biodiesel (JCB). Taking pyrogallol as the most effective antioxidant based on the earlier work of the authors, JCB was mixed with different transition metals – Fe, Ni, Mn, Co and Cu in different concentrations. Induction period (IP) was measured using Rancimat method (EN 14112). Based on results, several correlations are developed for assessing the oxidation stability in terms of IP as a function of antioxidant and metal concentration. A comparison between the experimental IP values and those predicted by the correlation shows that about 95% of the predicted data points lie within ±10% deviation lines of the experimental results. This is the first study of its kind being reported showing the relationship of IP with antioxidant concentration and metal contaminants. The correlations developed can be used to predict the amount of antioxidants required to stabilize the JCB. [Copyright &y& Elsevier]

Abstract: The vegetable oil, fats and their biodiesel suffer with the drawback of deterioration of its quality during long term storage unlike petroleum diesel due to large number of environmental and other factors making the fuel stability and quality questionable. There are various types of stabilities like oxidation, storage and thermal, playing key roles in making the fuel unstable. The present paper is an attempt to review the work done so far on the thermal stability of biodiesel and their blends with diesel under different conditions. The mechanism of thermal deterioration of vegetable oils, various methods of stability measurement including a new proposed method based on Karl Fischer coulometer, an alternative to conventional Rancimat test has been discussed. No correlations have been found in the literature among the results of various methods used. The effect of antioxidants on the stability parameters has also been discussed. TGA/DTA has been found as an effective method to check the deterioration of oil with respect to temperature using activation energy and order of reaction as the parameter to monitor the deterioration of oil. [Copyright &y& Elsevier]

Abstract: Biodiesel consists of long chain fatty acid esters derived from feed stocks such as vegetable oils, animal fats and used frying oil, etc. which may contain more or less unsaturated fatty acids which are prone to oxidation accelerated by exposure to air during storage and at high temperature may yield polymerized compounds. Auto oxidation of biodiesel can cause degradation of fuel quality by affecting the stability parameters. Biodiesel stability includes oxidation, storage and thermal stability. Oxidation instability can led to the formation of oxidation products like aldehydes, alcohols, shorter chain carboxylic acids, insolubles, gum and sediment in the biodiesel. Thermal instability is concerned with the increased rate of oxidation at higher temperature which in turn, increases the weight of oil and fat due to the formation of insolubles. Storage stability is the ability of liquid fuel to resist change in its physical and chemical characteristics brought about by its interaction with its environment and may be affected by interaction with contaminants, light, factors causing sediment formation, changes in color and other changes that reduce the clarity of the fuel. These fuel instabilities give rise to formation of undesirable substances in biodiesel and its blends beyond acceptable quantities as per specifications and when such fuel is used in engine, it impairs the engine performance due to fuel filter plugging, injector fouling, deposit formation in engine combustion chamber and various components of the fuel system. The present review attempts to cover the different types of fuel stabilities, mechanism of occurrence and correlations/equations developed to investigate the impact of various stability parameters on the stability of the fuel. A review of the use of different types of natural and synthetic antioxidants has also been presented which indicates that natural antioxidants, being very sensitive to biodiesel production techniques and the distillation processes have varying impacts on fuel stability and available literature is very much scarce. The work on the use of synthetic antioxidants on the stability of biodiesel (both distilled and undistilled) from various resources has indicated that out of various 8 synthetic antioxidants studied so far only 3 antioxidants have been found to increase the fuel stability significantly. However, effectiveness of these antioxidants is in the order of TBHQ>PY>PG. [Copyright &y& Elsevier]

The present study evaluated the effect of deficit irrigation strategies on the ornamental traits, physiological, biochemical and antiradical potential of two cultivars PNG and MGO of Tagetes erecta L.and Tagetes patula L, respectively. Deficit irrigation was applied in two ways a) plants were subjected to deficit irrigation (DI) at 50% field capacity (FC) as compared to control treatment (100% FC), b) regulated deficit irrigation (RDI) where DI was restricted to two stages of plants i.e. before initiation of floral buds and after 50% flowering. In between these two stages, non-limiting water supply was given to cultivars (100% FC). Findings of the experiments revealed that induction of secondary metabolites under DI and RDI could be taken into account for increased antioxidant activities in both the cultivars of Tagetes spp . Under second DI strategy (RDI), showed significant difference with DI at all phases. Flower yield was not significantly distinguishable compare to control treatment. Volatile principles of flowers of Tagete spp. produced under control, DI and RDI, were analyzed through GC–MS. Alpha-pinene, bicyclo heptane, limonene, p -cymene terpinolene, increased in RDI and DI compared to non-limiting water supply (control) in both Tagetes cultivars. Ocimene and n -decaldehyde content decreased under water deficit conditions as compared control. In both Tagetes species, ornamental traits like number of flowers, flower diameter and flower yield, exhibited positive correlation with photosynthetic rate (P n ), stomatal conductance (g s ) and relative chlorophyll content (RCC). In contrast, negatively relation was found with SOD, CAT and electrolyte leakage. [ABSTRACT FROM AUTHOR]