Mk Garg

Clarified Oil from Fluid Catalytic Cracking as an Additional Source of Group II Base Oil Components

Abstract Clarified oil (CLO) from a commercial fluid catalytic cracking unit was subjected to solvent extraction followed by solvent dewaxing and adsorption chromatography to analyze its various components for different end-use applications. The clarified oil was first solvent extracted using N-methyl pyrrolidone (NMP) to produce paraffinic rich raffinate (68.9 wt% yield). The raffinate thus obtained was dewaxed using methyl isobutyl ketone (MIBK) to get an oil of pour point 0°C. This dewaxed oil was then subjected to adsorption chromatography to determine group II base oil potential through yield v/s viscosity index (VI) curve. The results revealed that clarified oil has an actual potential of around 27.1 wt% of group II base oil components, suggesting that clarified oil can be used as an additional source of feed for production of group II base oil. This article also describes the potential of other components in clarified oil such as slack wax (24.2 wt%), aromatics (31.1 wt%), and low VI oil (17.6 wt%).

Upgrading low value refinery streams into electrode grade petroleum pitch

Abstract Petroleum pitch is an excellent precursor for a number of advanced carbon materials such as carbon fibres, carbon molecular sieves, mesocarbon micro-beads, activated carbon spheres, needle coke etc. Some of the refinery streams have good potential for making pitches. These streams are the by-products of petroleum refining processes. Currently, these streams are being sold as low value ‘fuel oils.’ The present study has been carried out to examine the feasibility of making electrode grade impregnating pitches from aromatic extract of waxy distillates, a by-product of lube refining. Pitches were prepared by thermally induced polymerization and condensation of aromatic extracts obtained by solvent extraction of waxy distillates. It was found that, it is possible to produce quality-impregnating pitches from aromatic extracts. These pitches are of good quality having key properties like softening point (112–128°C), coking value (>45 wt%) and quinoline insolubles (<1 wt%), and are well comparable with Ashlands A-240 pitch which is used as impregnating pitch in graphite electrode plants world over. Average structural parameters (Har, α-Ph, β-CH2, γ-CH3 etc.) of these pitches have been computed from NMR spectra and used for comparison purpose. It appears that integration of pitch making process in refineries will improve the profitability by converting low value aromatic extracts into high priced petroleum pitches.

Comparison of Structural Properties of Pitches Prepared from Petroleum Refinery/Petrochemical Residues using NMR Spectroscopy

Several petroleum pitches have been prepared by thermal treatment of various petroleum-derived residues such as clarified oil, aromatic extract and pyrolysis tars. These pitches were characterized physico-chemically (softening point, coking value, QI, & TI) and instrumentally (NMR) and compared. Attempts have been made to correlate physico- chemical properties of petroleum residues and pitches with their NMR structural parameters through regression analysis. Studies on high temperature in-situ 1 H NMR analysis of pitches have also been carried out. Structural characterization of petroleum residues and pitches is very useful for screening of petroleum residues and optimization of process variables for tailoring pitch properties for different end-use applications.

Novel Impact of Wet Dosages of NMP in Extraction for Production of High BMCI Carbon Black Feedstocks

Abstract In separation sciences, “Solvent Extraction” is one of the most important unit operations, a very widely used process, next only to distillation. In the petroleum refining industry, solvent extraction is commonly widely applied to produce a number of specialty products such as BTX, lube base oils, waxes, etc. There are many solvents used in various separation processes, like sulfolane, phenol, furfural, ketones, and N-methyl pyrollidone (NMP). NMP in particular is an environmentally benign, new generation solvent, which can be tailored for specific separations by using it in conjunction with small doses of water. In recent years, researchers are re-looking at the separation processes and their modifications to exploit these for producing high-value industrial products from low-value refinery streams. The present study deals with the production of high-quality carbon black feedstocks (CBFS) from clarified oils. The study shows the beneficial effect of using NMP in combination with different dosages of water as extraction solvent to extract low-value clarified oil, a cracked material from the FCC unit of an operating Indian refinery. In the present study, water ranging from 0.3 wt% to 10 wt% was used with NMP to produce aromatic extract of BMCI (Bureau of Mines Correlation Index) up to 146 through liquid-liquid equilibrium and mass transfer studies on clarified oil (CLO). The effect of solvent-to-feed ratio at constant temperature on solvent extraction was also studied. The addition of water in NMP alters the “selectivity” of solvent, which can be exploited for producing aromatic extracts of a wide range of BMCI for different end-use applications. The major users of such high BMCI extracts are carbon black and electrode pitch manufacturers. Regression analysis was also done to develop correlations between water percentage in NMP and targeted BMCI of aromatic extract. Presently, CLO is blended with fuel oil and sold as a very low value product in refinery. Since the demand of CBFS is increasing continuously and current short-fall in India is met through imports from China, Korea, and Japan, it is desirable that such studies are undertaken and will lead to production of high-value CBFS from low-value refinery streams through separation processes.

Employ NMP Extraction for Value Addition of Waxy Streams

Abstract With rising crude oil prices, coupled with tightening product specifications and environmental concerns, the refining industry will continue to see many changes during the times to come. In order to maintain/improve their margins, refiners are obliged to upgrade the low value streams into more profitable products. For upgrading the existing product slate, or manufacture of new products, huge investments are needed for new facilities. This involves logistic and proper evaluation of all the possible upgrading technologies and optimal processing schemes in order to arrive at the best option for a particular unit. This study deals with NMP extraction studies on two vacuum cuts; namely, pressible and heavy waxy distillates (PWD and HWD) for their up-gradation into raffinates of desired hydrocarbon composition and extracts of high aromaticity (BMCI). Solvent extraction studies were carried out on multistage extraction column in countercurrent mode. The water content in the solvent was optimized and kept the same for both the streams for ease of solvent recovery. The extraction conditions such as temperature, solvent-to-feed ratio, and water content in solvent were optimized for high quality raffinate and high quality aromatic extract (BMCI > 105). Studies reveal that the processing of PWD and HWD produces raffinate that could be used as feedstocks to solvent dewaxing/de-oiling unit for paraffin wax production. The high BMCI extract can be used as feed for high value industrial carbons such as pitches and needle coke. An added advantage of following this scheme is that the filtration rates of the NMP extracted PWD and HWD raffinates increase by ∼ 50% in comparison to that of raw distillates, thereby leading to capacity enhancement besides easy finishing of the wax. Moreover, withdrawal of about 25% of aromatic extracts from PWD and HWD feed stocks would lead to increase in capacity of the wax dewaxing/deoiling unit.

Evaluation of Different Packings in Lube Extraction System

Abstract Often the most cost effective way of enhancing mass transfer through improved mixing and settling of droplets in liquid-liquid extraction applied to lube systems is by way of using internals (packings). Although, such retrofits are generally performed to increase capacity, they also have been used to increase separation efficiency. Liquid extraction quite often proves to be an economical means of effecting a component separation. Packing material promotes mass transfer between the continuous and dispersed phases by forcing the phases to pass through interstices of the packings causing the dispersed phase droplets to follow a tortuous path through the packed bed. Most of the investigations in this direction have been carried out with respect to liquid and gas loadings. Commercial considerations have been the drivers to force the refineries and chemical plants to adopt new packings. However, there is room for carrying out R&D studies with respect to packings vis-à-vis lube extraction. An attempt has been made to initiate studies with relatively new generation packing, namely berl saddle, applied in lube systems, using N-methylpyrrolidone and comparing the findings with a standard conventionally employed packing (i.e., raschig rings). Preliminary studies indicate that the berl saddle performs better as compared to rasching rings in lube feed range (interneutral) taken from present studies.

PERSONALITY FACTOR CORRELATES OF GROWTH HORMONE AND HYPOTHERMIC RESPONSE TO BUSPIRONE CHALLENGE IN SUICIDAL SOLDIERS

The biological underpinnings of suicidal behaviour and possible rational pharmacotherapy of persons exhibiting such behaviour is the focus of this study. The study was conducted on 25 male Armed Forces personnel who attempted suicide and 25 matched healthy controls. Hypothermic and Growth Hormone response to Buspirone challenge was measured serially. 11 cases of attempted suicide had subsensitive postsynaptic 5 HT-1A receptors as indicated by blunted Growth Hormone response, while in other suicidal soldiers hypothermic response was markedly blunted indicating subsensitive presynaptic 5HT-IA receptors in the latter. Personality factor assessment carried out by 16 personality factor test, indicated overt extraversion marks for subsensitive postsynaptic 5 HT-IA receptors, while overt intraversion marks for subsensitive presynaptic 5 HT-IA receptors, in suicidal soldiers. In the light of the above, therapeutic options of Serotonin reuptake inhibition, agonist load at presynaptic 5 HT-IA and reciprocal stimulation of postsynatpic 5 HT-IA receptors for prevention of future attempts and completed suicides is discussed.

STENT IN ACUTE NON-Q WAVE MYOCARDIAL INFARCTION

Dear Editor, This is in reference to the case report “Stents in non-Q wave myocardial infarction” along with very informative discussion by Lt Col JS Duggal et al. Some important aspects though need to be highlighted. 1. Patients presenting with non-Q wave Myocardial Infarction (NQWMI) have a long term outcome, which is similar to that with a Q wave MI (QWMI), including the subset of patients who undergo coronary revascularisation (Fig 1). Thus, there has been extensive use of coronary arteriography (CAG) and revascularisation following NQWMI in an attempt to reduce subsequent morbidity and mortality. Fig. 1 The outcome alter angioplasty for recurrent ischemia after a Q wave or non-Q wave myocardial infarction is similar. Angioplasty was performed because of recurrent ischemia after a Q wave myocardial infarction (175 patients) or a non-Q wave infarction ... 2. Patients with mechanical complications, recurrent angina, electrical instability or congestive heart failure following NQWMI, have a very high risk of reinfarction and death. As a result, CAG followed by revascularisation is used extensively in these patients with complicated NQWMI. In uncomplicated NQWMI cases, routine CAG followed by PTCA of the culprit lesion performed days to weeks after acute NQWMI has become a standard practice at many centres. Only one trial, VANQWISH trial [1], which compared early and late coronary interventions in patients with NQWMI only, reveals that there is no evidence of benefit from an early invasive strategy in patients with uncomplicated NQWMI (Fig 2). Patients who do not have left ventricular (LV) dysfunction or inducible ischemia are at low risk of recurrent events and may well be harmed by unnecessary invasive procedures (Fig 3). Fig. 2 Conservative therapy is better after NQWMI Kaplan-Meier analysis demonstrates that, for patients with a non-Q wave myocardial infarction (NQWMI), a conservative strategy (catheterization and revascularization only for evidence of ischemia) results in ... Fig. 3 A conservatice management approach is effective for a non-Q wave myocardial infarction. Two studies have compared a conservative approach (medical therapy with catheterization and reascularization when clinically indicated) with an invasive approach (catheterization ... 3. Thus recommended approach to CAG and revascularization in patients of NQWMI based on those published by the ACC/AHA task force on practice guidelines (committee on coronary arteriography) [2] is as follows: Patients with cardiogenic shock should undergo immediate coronary angiography followed by PTCA or CABG if anatomy is suitable. Patients with mechanical complications, recurrent angina, electrical instability or CHF following NQWMI should also undergo prompt CAG followed by PTCA or CABG based upon anatomical considerations. Patients with uncomplicated NQWMI should have a non-invasive assessment of LV function and a physiologic evaluation for ischemia prior to discharge. Those with significant LV dysfunction or evidence of inducible ischemia should undergo CAG followed by revascularisation based upon anatomic considerations. There is no apparent benefit from an early invasive approach. The remaining patients are at low risk for recurrent events and should be treated medically. 4. As per recent ACC/AHA guidelines for treatment of patients with NQWMI, Diltiazem is recommended in patients only if there is no LV dysfunction or pulmonary congestion [2]. Also, short-term therapy with ACE inhibitors appears to be beneficial in NQWMI patients with anterior infarction and long-term treatment appears to be effective in those with reduced LV function [3]. 5. Stents in acute MI have come a long way. A large number of case reports and small series support a potential role for intra-coronary stents for acute Ml with success rate reported from 81 to 98%. Although primary stenting improves the short-term outcome of patients, long-term data are sparse. The American College of Cardiology experts consensus documents state that stenting is a promising approach to optimize the results of primary angioplasty for acute Ml and to treat complications [4]. Whether stenting should be used only to treat sub-optimal results or should be recommended as a primary therapy, is still uncertain.

ATRIAL FIBRILLATION IN THYROTOXICOSIS

dissociation with interference-lsorrhythmic arrhythmia AVdissociation occurs when atriaand ventricleare undercontrol ofseparate pacemakers[I]. The atria is under control ofeither sinus node, ectopic atrinJ or AVjunctional rhythm. Incomplete AV dissociation is indicated when a single pacemaker establishes control of both atria and ventricle for eitherone beat (capture) or series ofbeats (sinus rhythm, AVjunctional rhythm with retrograde atrial capture [2]. Our ECG reveals both the mechanism. AV dissociation can occur by slowing ofdominant pacemaker, acceleration of latent pacemaker, complete AV blocks and combination ofabove[2]. In our case it was due to combination ofslowing of dominant pacemaker (second strip) and acceleration of latent

LAURENCE-MOON-BARDET-BIEDL SYNDROME – PRESENTING WITH ACUTE ONSET OF DIABETES MELLITUS

Introduction Laurence-Moon-Biedl (LMB) syndrome is a rare familial disorder, inherited by autosomal recessive characteristic with variable penetrance and expressivity [1]. This syndrome is characterized by 5 cardinal features obesity (95%), mental retardation (90%), retinal degeneration (90%), hypogonadism (75%), and Polydactyly (75%) [2]. The pentad of symptoms is present in less than half of the cases. However some workers differentiate between Laurence-Moon and Bardet-Biedl syndrome by the presence or absence of Polydactyly and spastic paraparesis [3-4]. Several cases have been reported with variable features [2,5]. Glucose intolerance is reported in 14-45 per cent of cases [2,4,6] but diabetes mellitus requiring drug treatment is rare. Here we report a case of LMB syndrome who has presented with acute onset of diabetes mellitus requiring insulin treatment.