Desulfurization

The powder-particle spouted bed process is one of the semi-dry processes that have been developed for flue gas desulfurization. In this study, which is designed for SO 2 removal by a powder-particle spouted bed, the reaction term is included in one-dimensional and streamtube models that were presented previously for spouted beds. Hydrated lime is used as the sorbent in this process. The predictions of the models are compared with some published experimental data and it is found that the developed models are valid. The results of two models are compared with each other and their various properties are evaluated. The effects of different operating conditions on SO 2 removal efficiency are also investigated and preferred operating conditions are discussed.

Hydrated lime is normally used as SO sorbent in spray dry scrubbers, whereas limestone is considered unreactive under conditions prevailing in such a system. However, limestone is more easily available and several times cheaper than hydrated lime. We tried to use limestone to remove SO from #ue gas in the semidry FGD process with a powder-particle spouted bed. If limestone can be utilized in the process it would be of particular advantage. In the present study, the e!ects of operating parameters on SO removal were investigated, such as Ca/S molar ratio, particle size of SO sorbent, apparent residence time of gas in the bed and approach to saturation temperature. The comparison of reactivity with SO between limestone and hydrated lime was also made based on their structural properties. The experimental results showed that SO removal e$ciency of limestone was considerably enhanced in the present process by increasing Ca/S molar ratio and decreasing the approach to saturation temperature and sorbent size. Thus, the present process with limestone as SO sorbent may be an attractive alternative to other FGD technologies in terms of removal e$ciency, price and availability of sorbent.

Absorption of SO2, diluted with nitrogen up to concentrations of 500 Pa, was performed at 20 °C and 1 atm, with water and sulfuric acid solutions containing hydrogen peroxide in two different contactors: a packed column and a cable scrubber. The absorption rate was determined for various SO2 partial pressures, as well as different concentrations of sulfuric acid (up to 40 wt %) and of hydrogen peroxide in the scrubbing liquid. It was found that the SO2 absorption rate increases with the hydrogen peroxide concentration, and decreases as the acidity of the scrubbing liquid increases. Taking into account hydrodynamic and mass transfer characteristics of the packing for both scrubbers, a practical enhancement factor depending on the liquid phase H2SO4 and H2O2 contents, was deduced from semi-continuous tests. As a good concordance was observed between results determined for both contactors, a single correlation is proposed, allowing the computation of this kinetic factor for quite simple simulation or design of SO2 scrubbers, provided the gas and liquid phase mass transfer coefficients kGa and kLa are known.

The powder-particle spouted bed process is one of the semi-dry processes that have been developed for flue gas desulfurization. In this study, which is designed for SO 2 removal by a powder-particle spouted bed, the reaction term is included in one-dimensional and streamtube models that were presented previously for spouted beds. Hydrated lime is used as the sorbent in this process. The predictions of the models are compared with some published experimental data and it is found that the developed models are valid. The results of two models are compared with each other and their various properties are evaluated. The effects of different operating conditions on SO 2 removal efficiency are also investigated and preferred operating conditions are discussed.

The adsorption behavior of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from n-heptane was investigated onto activated carbon cloth (ACC) and its modified forms at 30°C in batch condition. ACC was modified by HNO 3 , (NH 4 ) 2 S 2 O 8 , H 2 SO 4 , HCl and NaOH at ambient temperature. The adsorbents were characterized using nitrogen adsorption/desorption. It was found that the adsorbents are mainly microporous but differ in their surface chemistry, which is related to the effect of oxidizing agent. The adsorption process was studied from both equilibrium and kinetics point of view. The equilibrium experimental data were fitted to the Langmuir, Freundlich and Langmuir-Freundlich by non-linear method. Among the tested adsorbents, the modified ACC with HNO 3 (ACC-HNO 3 ) had the highest capacity for adsorption of DBT. Kinetic characterization of the adsorption process indicated that the mixed-order and modified pseudo-n-order models can describe the kinetics of adsorption of thiophenic compounds onto ACCs. The ACC and ACC-HNO 3 were used to test the removal efficiency of total sulfur contents (BT, DBT and DMDBT, 150 ppmw for each of them), too. The effect of shaking and ultrasound methods and also temperature and time on the regeneration of saturated ACC-HNO 3 with DBT was studied.

This study demonstrates that CH 3 SH (a harmful impurity in natural gas) can be selectively converted into H 2 S and hydrocarbons (M2TH process) on H-zeolite/zeotype with diverse topologies. The catalytic activity varied as follows: H-ZSM-5 > H-Y > H-FER > H-BEA > H-MOR > H-SAPO-34. In addition, H-ZSM-5 was the most stable catalyst toward deactivation by coke. The effect of the carrier gas (nitrogen or methane) and the role of water on the catalytic behavior of zeolites were explored under different conditions. Similar performances were obtained using CH 3 SH/N 2 or CH 3 SH/CH 4 mixtures, but the amount of coke drastically decreased and the catalyst lifetime increased when 2% of water was added into the reaction. M2TH was compared with the well-known MTH (methanol to hydrocarbons) process. Although there are similarities between the two processes, significant differences were also observed, essentially regarding the products formed and distributed. These aspects are discussed taking into account the reaction pathway involved in each process.

The world production of petroleum coke has been growing in the last years, due to a growing supply of heavy oils. The market is divided among the green coke consumers and the calcinate coke consumers. When taking pollutants into consideration, the quality of petcoke depends on the type of processed petroleum and the operational conditions of the production unit. Three different processes can produce petcoke. The cost of petcoke is inversely proportional to its sulfur content. Due to the consumer process type, there are those who can only use coke with low sulfur content. However, there are consumers that can burn coke with larger sulfur content without needing exhausted gas desulfurization treatments, such as power plants with fluidized bed boilers, and in the cement industry where the sulfurous gases incorporate to the clinker in the form of calcium sulfate.

This review discusses the problems of sulfur reduction in highway and non-road fuels and presents an overview of new approaches and emerging technologies for ultra-deep desulfurization of refinery streams for ultra-clean (ultra-low-sulfur) gasoline, diesel fuels and jet fuels. The issues of gasoline and diesel deep desulfurization are becoming more serious because the crude oils refined in the US are getting higher in sulfur contents and heavier in density, while the regulated sulfur limits are becoming lower and lower. Current gasoline desulfurization problem is dominated by the issues of sulfur removal from FCC naphtha, which contributes about 35% of gasoline pool but over 90% of sulfur in gasoline. Deep reduction of gasoline sulfur (from 330 to 30 ppm) must be made without decreasing octane number or losing gasoline yield. The problem is complicated by the high olefins contents of FCC naphtha which contributes to octane number enhancement but can be saturated under HDS conditions. Deep reduction of diesel sulfur (from 500 to <15 ppm sulfur) is dictated largely by 4,6-dimethyldibenzothiophene, which represents the least reactive sulfur compounds that have substitutions on both 4-and 6-positions. The deep HDS problem of diesel streams is exacerbated by the inhibiting effects of co-existing polyaromatics and nitrogen compounds in the feed as well as H 2 S in the product. The approaches to deep desulfurization include catalysts and process developments for hydrodesulfurization (HDS), and adsorbents or reagents and methods for non-HDS-type processing schemes. The needs for dearomatization of diesel and jet fuels are also discussed along with some approaches. Overall, new and more effective approaches and continuing catalysis and processing research are needed for producing affordable ultra-clean (ultra-low-sulfur and low-aromatics) transportation fuels and non-road fuels, because meeting the new government sulfur regulations in 2006-2010 (15 ppm sulfur in highway diesel fuels by 2006 and non-road diesel fuels by 2010; 30 ppm sulfur in gasoline by 2006) is only a milestone. Desulfurization research should also take into consideration of the fuel-cell fuel processing needs, which will have a more stringent requirement on desulfurization (e.g., <1 ppm sulfur) than IC engines. The society at large is stepping on the road to zero sulfur fuel, so researchers should begin with the end in mind and try to develop long-term solutions.

Peroxidases have many potential uses for biotechnological processes. In this review, peroxidase-catalyzed reactions potentially applicable to the petroleum industry are described. Although peroxidases are attractive catalysts for desulfurization, aromatic oxidation and asphaltene transformation, there are important issues that must be overcome before any industrial application can be considered. The opportunities and challenges of enzymatic petroleum biorefining are documented and discussed, with emphasis on the available tools to design a biocatalyst with appropriate performance for the oil and other industries.

Bacteria of the sulphur cycle, in particular sulphate reducing and sulphide oxidizing bacteria, are of immense importance from the industrial and environmental point of views. While biogenic production of H 2 S by sulphate reducing bacteria creates severe processing and environmental problems for the petroleum industry and agriculture sector, when used in a properly designed and controlled bioreactor sulphate reducing bacteria could play an instrumental role in the treatment of acid mine drainage, a major environmental challenge faced by the mining industry. Biooxidation of sulphide and intermediary sulphur compounds carried out by sulphide oxidizing bacteria are crucial in biotreatment of acid mine drainage and in the bioleaching of refractory minerals. Moreover, sulphide oxidizing bacteria are known as major players in the in situ removal of H 2 S from the onshore and offshore oil reservoirs and are used in the ex situ processes for the treatment of sour gas and sulphide laden waters. Owing to the numerous environmental and industrial applications, the bacteria of the sulphur cycle have been subject of numerous studies. The present article aims to provide an overview of the microbiology, biokinetics, current and potential applications of the bacteria of sulphur cycle and the reactions which are carried out by these versatile microorganisms. Special consideration is given to the role of these bacteria in the biotreatment of acid mine drainage, oil reservoir souring and the treatment of H 2 S-containing gaseous and liquid streams.

Thermal power plants (TPPs) that burn fossil fuels emit several pollutants linked to the environmental problems of acid rain, urban ozone, and the possibility of global climate change. As coal is burned in a power plant, its noncombustible mineral content is partitioned into bottom ash, which remains in the furnace, and fly ash, which rises with flue gases. Two other by-products of coal combustion air-pollution control technologies are flue gas desulfurization (FGD) wastes and fluidized-bed combustion (FBC) wastes. This paper analyzed and summarized the generation, characteristics and application of TPP solid wastes and discussed the potential effects of such solid wastes on the environment. On this basis, a review of a number of methods for recovery of metals from TPP solid wastes was made. They usually contain a quantity of valuable metals and they are actually a secondary resource of metals. By applying mineral processing technologies and hydrometallurgical and biohydrometallurgical processes, it is possible to recover metals such as Al, Ga, Ge, Ca, Cd, Fe, Hg, Mg, Na, Ni, Pb, Ra, Th, V, Zn, etc., from TPP solid wastes. Recovery of metals from such wastes and its utilization are important not only for saving metal resources, but also for protecting the environment.

The desulfurization of the actual heavy crude oil is one of the most important processes in petroleum industries due to the low quality of those types of oil and containing large amounts of sulfur compounds, high viscosity and density. In the present work, the desulfurization of the actual heavy crude oil with a sulfur content 5.8 wt. % from Al-Halfaya Oil Field in southern Iraq was studied using a sodium hydroxide-assisted process. Effects of the operating conditions such as: reaction time (30-60 min), temperature (30-50 • C), the amount of NaOH in its solution (10-30 gm), and mixing speed (300-500 rpm) were investigated. The desulfurization process was achieved in a batch reactor by implementation of the experimental design technique. The objective function (response) was the sulfur content wt. % while a response surface method (RSM) was applied to define the significant factors that affect the desulfur-ization process. It was found that effects of the four variables take the following sequence: mixing speed > weight of NaOH > time > temperature. The optimum conditions of the proposed model were obtained using optimization techniques and found as follows: time = 60 min., temperature = 40 • C, NaOH solution = 18gm and mixing speed = 500 rpm. The optimum conditions of the sulfur content were applied experimentally and theoretically was equal to 2.5 and 2.3 wt. %, respectively. It is concluded that the efficiency of the sulfur removal content for actual heavy crude oil by this process was 56.89 %.

A mathematical model is developed for simulation of dry sodium bicarbonate (NaHCO ) duct injection for the 3 removal of sulfur dioxide (SO ) in flue gases across a fabric filter (baghouse). The model employs parallel reaction 2 kinetics and assumes that the sodium bicarbonate injection process can be separated into two stages. The first stage is a transport duct section where NaHCO particles are injected into the sulfur dioxide laden gas stream. The second 3 stage is the fabric filter section where sodium sorbents are collected and behave as a variable depth fixed bed reactor. The process simulation for the efficiency of desulfurization in flue gas is performed and evaluated for a variety of operating conditions such as system temperature, particle size, residence time, normalized stoichiometric ratio, concentration of sulfur dioxide and decomposition time. It is found that the removal of SO within the duct section 2 is small and negligible for most practical conditions, with a contribution normally less than 5% of total SO removal. 2 The major removal of SO occurs across the filter cake, which accumulates the sorbent particles on the fabric filter. 2 These particles are periodically disposed as the filter is cleaned. The major factors for the process are temperature, particle size and SO gas concentration for all operating conditions. At low temperatures, the removal of SO 2 2 increases as temperature increases, but the removal decreases at higher temperatures due to the impact of the thermal decomposition reaction of NaHCO on SO removal. It was found that the temperature for the highest removal of 3 2 SO is within the range of 127-150 8C and the removal efficiency also depends on particle size. 2

a b s t r a c t CO 2 capture system based on the carbonation/calcination loop, still in its infancy, has gained rapid interest due to promising carbonator CO 2 capture efficiency, low sorbent cost and the fact that no flue gases desulphurization unit is needed before entering the system. The sum of these features results in a competitively low cost CO 2 capture system. There are different options to design the carbonation loop. In this work, a basic configuration that makes use of two interconnected circulating fluidized beds (carbonator and calciner) has been studied. Among the key variables that influence the performance of these systems, the carbonation conversion of the sorbent and the heat requirement at calciner are the most relevant. Both variables are mainly influenced by CaO/CO 2 ratio and make-up flow (purge) of solids. A purge is necessary in order to reduce the sorbent deactivation and to compensate the formation of CaSO 4 from the SO x content in the flue gas. Large CaO/CO 2 ratios improve the carbonation conversion but also increase the cost of the system due to a more intensive solid circulation. High make-up flow also improves the carbonation conversion and hence the CO 2 capture, but increases the heat demand at calciner and the fresh sorbent cost. The aim of this paper is to calculate the optimum make-up flow and CaO/CO 2 ratio in order to minimize the capture cost of the system. Independent variables are make-up flow of fresh CaCO 3 and CaO/CO 2 ratio. The constraint equations are experimental data on carbonation reaction, mass and energy balances, oxygen requirement and fuel composition.

The reduction of FeO-containing slag by blends of metallurgical coke and end-of-life tyres (RT) have been investigated through experiments conducted in a laboratory-scale horizontal tube furnace. Composite pellets of EAF slag (47.1% FeO) with coke, RT, and blends of coke/RT (in four different proportions) were rapidly heated at 15508C under high purity argon gas and the off gas was continuously analyzed for CO and CO 2 using an online infrared (IR) gas analyzer. The extent of reduction after 10 min, level of carburization and desulfurization, and the total amount of CO 2 emissions were determined for each carbonaceous reductant. The results indicate that the extent of reduction, level of carburization and desulfurization of the reduced metal are significantly improved when coke is blended with RT. Blending of coke with RT resulted in a decrease in direct CO 2 emissions from the reduction reactions.

Research has been conducted under United States Department of Energy Contract DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant, called a Second Generation Pressurized Fluidized Bed Combustion Plant (2 nd Gen PFB), offers the promise of efficiencies greater than 48 percent, with both emissions and a cost of electricity that are significantly lower than those of conventional pulverized coal-fired (PC) plants with wet flue gas desulfurization. The 2 nd Gen PFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed boiler, and the combustion of carbonizer syngas in a gas turbine combustor to achieve gas turbine inlet temperatures of 2300°F and higher. A conceptual design and an economic analysis was previously prepared for this plant. When operating with a Siemens Westinghouse W501F gas turbine, a 2400psig/1000ºF/1000ºF/2-1/2 in. Hg. steam turbine, and projected carbonizer, PCFB, and topping combustor performance data, the plant generated 496 MWe of power with an efficiency of 44.9 percent (coal higher heating value basis) and a cost of electricity 22 percent less than a comparable PC plant. The key components of this new type of plant have been successfully tested at the pilot plant stage and their performance has been found to be better than previously assumed. As a result, the referenced conceptual design has been updated herein to reflect more accurate performance predictions together with the use of the more advanced Siemens Westinghouse W501G gas turbine. The use of this advanced gas turbine, together with a conventional 2400 psig/1050°F/1050°F/2-½ in. Hg. steam turbine increases the plant efficiency to 48.2 percent and yields a total plant cost of $1,079/KW (January 2002 dollars). The cost of electricity is 40.7 mills/kWh, a value 12 percent less than a comparable PC plant.

h i g h l i g h t s 2-Methylfuran gasoline blend and ethanol gasoline blend were compared in a SI engine. Combustion duration, thermal efficiency and regulated emissions were studied. Compared with E10, BSFC and COV of IMEP can be improved by M10 blend. M10 are similar to E10 and superior to gasoline in terms of HC and CO emissions. NO X emissions increase is found by using M10 blend fuel. a b s t r a c t Currently, 2,5-dimethylfuran (DMF) has already been extensively studied as a novel potential gasoline substitute. With its improved reaction sequences, another main molecule transformed from fructose has also aroused worldwide interest, which is known as 2-methylfuran (MF). MF has similar energy density and knock suppression ability to DMF. However, little is known about its behavior in spark-ignition (SI) engines, especially when it is used as a gasoline additive. Therefore, focus was given on the combustion and emissions characteristics of 10% volume fraction 2-methylfuran gasoline blend fuel (M10) in this work, which was investigated experimentally in a single-cylinder four-stroke SI engine at various engine speeds (800-1800 rpm in 200 rpm intervals) and wide open throttle (WOT). The in-cylinder combustion process as well as engine performance of M10 were compared with gasoline and the same proportion ethanol gasoline blend fuel (E10) under gasoline maximum brake torque (MBT) spark timing and stoichiometric air-fuel ratio. Results of engine tests show that M10 produces relatively high in-cylinder peak pressure and temperature, which is mainly attributed to its consistently shorter combustion duration. Compared with engine performance of E10, the output torque and brake power increase slightly with less brake specific fuel consumption when M10 is used. Lower regulated gas emissions of hydrocarbons (HC) and carbon monoxide (CO) can be found for both E10 and M10 blend. In addition, more nitrogen oxides (NO X ) emissions are generated from M10 due to its higher combustion temperature.

The main objective of this investigation consists in the biogas purification coming from the anaerobic digestion of sludges in a wastewater treatment plant, in order to be used later as biofuel for vehicles. This article consists of the optimization of the biogas desulphurization. In our case, this process was achieved in a chemical way. Besides the scrubbing towers, the pilot plant used included filters of activated carbon at the end of the line. The H 2 S inflow concentrations were quite high. The effluent biogas from the scrubbing towers presented an H 2 S concentration less than 1 ppm and zero or undetectable values were obtained for up to 58 analyzed trace elements.

Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing a-calcium sulfate hemihydrate (a-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to a-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl 2 solution containing Mg 2+ and Mn 2+ at 95°C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of a-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with a-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of a-HH.

A new strategy for preparing porphyrins that bear up to four different meso-substituents (ABCD-porphyrins) relies on two key reactions. One key reaction entails a directed synthesis of a 1-protected 19-acylbilane by acid-catalyzed condensation at high concentration (0.5 M) of a 1-acyldipyrromethane and a 9-protected dipyrromethane-1-carbinol (derived from a 9-protected 1-acyldipyrromethane). Three protecting groups (X) were examined, including thiocyanato, ethylthio, and bromo, of which bromo proved most effective. The bilanes were obtained in 72-80% yield, fully characterized, and examined by 15 N NMR spectroscopy. The second key reaction entails a one-flask transformation of the 1-protected 19-acylbilane under basic, metal-templating conditions to give the corresponding metalloporphyrin. The reaction parameters investigated for cyclization of the bilane include solvent, metal salt, base, concentration, temperature, atmosphere, and time. The best conditions entailed the 1-bromo-19-acylbilane at 100 mM in toluene containing DBU (10 mol equiv) and MgBr 2 (3 mol equiv) at 115°C exposed to air for 2 h, which afforded the magnesium porphyrin in 65% yield. The magnesium porphyrin is readily demetalated to give the free base porphyrin. A stepwise procedure (which entailed treatment of the 1-(ethylthio)-19acylbilane to oxidation, metal complexation, desulfurization, carbonyl reduction, and acid-catalyzed condensation) was developed but was much less efficient than the one-flask process. The new route to ABCD-porphyrins retains the desirable features of the existing "2 + 2" (dipyrromethane + dipyrromethane-1,9-dicarbinol) method, such as absence of scrambling, yet has significant advantages. The advantages include the absence of acid in the porphyrin-forming step, the use of a metal template for cyclization, the ability to carry out the reaction at high concentration, the lack of a quinone oxidant, avoidance of use of dichloromethane, and the increased yield of macrocycle formation to give the target ABCDmetalloporphyrin.

There is a considerable demand to reduce the content of sulfur-containing compounds (S-compounds) such as thiophene (Th), benzothiophene (BT), and dimethyldibenzothiophene (DMDBT) in fuels like diesel and gasoline to a low level to prevent air pollution and deactivation of catalysts. [1, 2] So far, various methods have been investigated for sulfur removal, [3] and adsorption has been regarded as one of the most competitive methods. For efficient adsorption, not only adequate porosity/pore size but also specific adsorption sites are required. [3] Remarkable progress on porous materials has been achieved because of the developments of metal-organic framework materials (MOFs) and coordination polymers (CPs). The importance of MOF-type materials is due to the huge porosity, easy tunability of their pore size and shape, and potential applications. [6] Recently, the MOF-type materials have also been investigated for the removal of harmful materials such as S-compounds, [1, 2] dyes, [7] N-containing compounds, and benzene from liquids. Gaseous sulfur compounds have also been removed using MOFs. [1, A few important factors, such as open metal sites, [1] acid sites, and pore functionality have been suggested for the efficient removal of S-compounds. However, little has been understood for the high uptake of S-compounds with modified MOFs as adsorbents.

Presently, decentralized feedback control is the only control strategy used in wet limestone flue gas desulfurization (WLFGD) plants. Proper tuning of this control strategy is becoming an important issue in WLFGD plants because more stringent SO 2 regulations have come into force recently. 3 Controllability analysis is a highly valuable tool for proper design of control systems, but it has not been applied to WLFGD plants so far. In this paper a decentralized control strategy is designed and applied to a WLFGD pilot plant taking into account the conclusions of a controllability analysis. The results reveal that good SO 2 control in WLFGD plants can be achieved mainly because the main disturbance of the process is well-aligned with the plant and interactions between control loops are beneficial to SO 2 control.

The catalytic conversion of C 2 H 5 SH on protonic molecular sieves, i.e. ZSM-5 with various Si/Al ratios, Ferrierite, Y, SAPO-34, was studied in a gas flow reactor. Ethylene and H 2 S are the main products, but small amounts of C1-C4 alkanes, C6-C8 aromatics, coke, CS 2 and thiophenes are formed. The catalytic behavior strongly depended on both acidic and textural properties of solids. Assuming a pseudo first order kinetic model, the rate constant and the activation energy have been evaluated for all catalysts. Over the best catalytic material, H-ZSM-5 (Si/Al = 15), full conversion of C 2 H 5 SH was achieved at temperature higher than 673 K. Additionally, the catalyst lifetime measured at 823 K was more than 70 h of time-onstream. With C 2 H 5 SH/CH 3 SH mixture, over H-ZSM-5, the conversion of thiols was total at 823 K for at least 11 h. In that case, significant amounts of coke and aromatics were formed, but after the thermal regeneration with air, the spent catalyst recovered the properties of the fresh zeolite.

Desulphurization of gasoline and kerosene was carried out using organic and inorganic oxidants. Among the organic oxidants used were hydrogen peroxide in combination with acetic acid, formic acid, benzoic acid and butyric acid, while inorganic oxidants used included potassium permanganate and sodium perchlorate. The oxidation of each petroleum oil was carried out in two steps; the first step consisted of oxidation of the feed at moderate temperature and atmospheric pressure while in the second step, the oxidized mixture was extracted with azeotropic mixture of acetonitrile-water. A maximum desulphurization has occurred with NaClO 4 and hydrogen peroxide and acetic acid, which are 68% and 61%, respectively in case of gasoline and 66% and 63%, respectively in case of kerosene oil. The FTIR study of the whole and variously desulphurized gasoline and kerosene was also carried out. The results indicate considerable desulphurization by absence of bands that corresponds to sulphur moieties in NaClO 4 and hydrogen peroxide treated samples.

Depending on advanced technological developments in energy production the low quality coals needed the most economical technologies and even in order to make it possible to produce coal-derived products. Compliance with environmental norms of coal pyrolysis or gasification of various type of coals, feasible combustion systems and energy production facilities are needed in today's modern technology, also enable the production of liquid and gaseous coal fuels. However, raw materials and chemical nature of them requires a variety of adaptation methods. This study examined the high sulfur and ash types of Kütahya, Denizli, Aydin, Soma lignite, Sirnak asphaltite and lignite. The representative samples were taken from local areas of the lignites. Fundamentally, the conditions regarding better desulfurization way, the high quality pyrolysis lignite oil production, high value light oil, coal tar and gas products were determined at the goal of high fuel producing yield.

The present work estimated the ability for the removal of phosphorus and sulfur from hot metal with CaO-Si02-CaF2fluxes which contain 20masso/• CaF2 and [mass'/•CaO/masso/oSi02]=4. Silicon losses were also determined along the treatment. Some additions of FeO (4 to 8 masso/o) and Na20 (1 to 6 mass'/o) were used to changethe oxygen potential of the molten iron. The experiments were carried out in an open 1O kg induction furnace using Al203 refractory in the temperature range 1 350-1 400'C.

We present density functional theory (DFT) calculations of reaction pathways for both the hydrogenation (HYD) and direct desulfurization (DDS) routes in the hydrodesulfurization (HDS) of thiophene over the different MoS 2 edge structures, which will dominate under typical HDS reaction conditions. Contrary to the generally accepted view, we find that the HYD reaction path, which involves hydrogenation to 2-hydrothiophene followed by hydrogenation to 2,5-dihydrothiophene and subsequent S-C scission, can occur at the equilibrium Mo(1010) edge without the creation of coordinatively unsaturated Mo edge sites. This is related to the presence of the metallic-like brim sites also observed in previous STM studies. It is found that the HYD reaction pathway also can occur at the S(1010) edge. At this edge, the equilibrium edge structure itself is not active, and sulfur vacancies must be created for the reaction to proceed. It is found that the effective energy barrier for vacancy creation depends on the H 2 partial pressure. The sulfur vacancies at the S(1010) edge are also found to be active sites for the DDS pathway. This pathway does involve an initial hydrogenation step to 2-hydrothiophene, followed by S-C scission. Analyzing the relative stabilities of reactants and intermediates suggests that a catalytic cycle may involve elementary steps that start at one type of edge and are completed at the other; for example, many intermediates are more stable at the S edge. The regeneration of the active sites is found to be a crucial step for all of the reaction pathways, and the importance of reactions at Mo brim sites is related to the observation that regeneration is least activated here. It is proposed that an important activity descriptor is the minimum energy required to either add or remove S from the different equilibrium edge structures.

This paper reports the results of desulphurization of organic sulphur from a subbituminous Meghalaya coal by the electron transfer process accomplished with the metal ion Co 2+ . The process was studied both in presence and absence of naphthalene which is used as an electron transfer agent. Temperature dependence on desulphurization unfolded that as the temperature is raised from 25 to 50 8C, there is increase in desulphurization performance. Model organic sulphur compounds study revealed that the desulphurization process is effective with aliphatic type of compounds. Infrared spectroscopic study revealed the release of easily removable sulphur compounds as the band intensities due to ÀSMO and ÀSO 2 groups have declined considerably in their respective regions in the desulphurized coals. The degree of desulphurization is 28.5 wt.% in the presence of naphthalene and 24.6 wt.% in absence of naphthalene, both at 4 h and 50 8C. The sulphur extrusion process is continuous and application of a first-order kinetic model produced specific rate constants of the desulphurization reaction in the two systems, at different temperatures, which falls in the range of (1.3-2.9)Â10 À5 s À1 . The activation energy of the sulphur-loss reaction in the system containing naphthalene (26.8 kJ mol À1 ) is about 12% lower than that of the system without naphthalene (30.6 kJ mol À1 ). The frequency factor of the sulphur removal reaction in the systems have been found to be in the range of 0.8-3.2 s À1 , suggesting low amount of successful collisions and an associated type of reaction. The desulphurization reaction is nonspontaneous in nature, proceeds with the absorption of heat and there is reduction in the degree of disorderliness in the system as predicted by the transition state theory. D

FeCl3 based imidazolium ionic liquids were synthesized and employed as
novel solvents in extractive desulfurization for removal of dibenzothiophene, thiophene,
benzothiophene, 3-methylthiophene, and 4,6-dimethyldibenzothiophene in model fuel.
FeCl3 based ionic liquids such as 1-butyl-3-methylimidazolium chloride iron chloride
[C4MIM]Cl/FeCl3, 1-octyl-3-methylimidazolium chloride iron chloride, didecyldimethyl
ammonium chloride iron chloride, ammonium tributyl-methyl chloride iron chloride, and
trioctyl-methyl ammonium chloride iron chloride were synthesized and screened for extractive
desulfurization of liquid fuel. Due to the redox properties of [C4MIM]Cl/FeCl3
with addition of hydrogen peroxide, dibenzothiophene removal can reach 92 % under mild
reaction conditions, which is not only higher than simple extraction with ionic liquids, but
better than other FeCl3 based ionic liquids under the same reaction conditions. The spent
[C4MIM]Cl/FeCl3 can be recycled without regeneration for five times with only a slight
decrease in activity. Also, desulfurization and multistage extraction of real fuels with
[C4MIM]Cl/FeCl3 were studied. The data and results provided in the present paper provide
significant insights into FeCl3 based imidazolium ionic liquids as novel solvents for
desulfurization of liquid fuels.

The effect of ionic liquid loading, extraction temperature, and extraction time in the removal of dibenzothiophene from dodecane were investigated. Eighteen (18) ionic liquids were screened for its dibenzothiophene extraction ability. Imidazolium based ionic liquids with thiocyanate, dicyanamide and octylsulfate anions exhibited the highest extraction capabilities with 66.1%, 66.1%, and 63.6% of extraction efficiency respectively. Tributylmethylammonium methylcarbonate ionic liquid gave 61.9% extraction efficiency, which showed that π-π interaction between aromatic rings of sulfur compound and ionic liquid (IL) was not be the main extraction mechanism. A trend between specific volume and desulfurization efficiency of ILs was put forward, enabling researchers to predict ILs' desulfurization efficiency from its specific volume. It was also found that [C 4 mim][SCN] can be reused in extraction without regeneration with considerable extraction efficiency of 41.9%. Huge saving on energy can be achieved if we make use of this IL behavior in process design, instead of regenerating IL after every time of extraction.

In order to obtain the ultra low-sulfur diesel, deep desulfurization of diesel oil has become a vital subject of environmental catalysis studies. Extraction and catalytic oxidation desulfurization (ECODS) system is one of the most promising desulfurization processes. A series of Keggin-type POM-based ionic liquids hybrid materials [MIMPS] 3 PW 12 O 40 ·2H 2 O (1-(3-sulfonic group) propyl-3-methyl imidazolium phosphotungstate), [Bmim] 3 PW 12 O 40 (1-butyl 3-methyl imidazolium phosphotungstate), [Bmim] 3 PMo 12 O 40 (1-butyl 3-methyl imidazolium phosphomolybdate) and [Bmim] 4 SiW 12 O 40 (1-butyl-3-methyl imidazolium silicotungstate) have been developed in this study, and the reaction has performed using the POM-ILs materials as catalysts, H 2 O 2 as oxidant, and ionic liquid (IL) as solvent. Through experimental evaluations, [MIMPS] 3 PW 12 O 40 ·2H 2 O was found to be the best catalyst, with an S-removal of 100% at 30°C for 1 h. The main factors affecting the process including temperature, catalyst dosage, and O/S (H 2 O 2 /DBT) molar ratio were investigated in detail.

The effective management of mine tailings involves the control of several environmental impacts and legal requirements. Six tailings site management and closure scenarios were developed for a copper zinc underground mine located in Quebec (Canada) and compared using life cycle assessment (LCA). Two options are considered for the mine operation: tailings can be sent to the tailings disposal area where they are submerged or they can be partly used for backfilling. For each of these two operation options, three alternatives are presented for mine closure: (a) submerged tailings, (b) partial desulphurization with a cover of desulphurized material and (c) a cover with capillary barrier effects (CCBE) made of natural soils followed by revegetation. The goals of the study were to draw the inventory of these management scenarios from the development to the post-closure phase, to assess and compare their environmental impacts and to determine the importance of the land-use impact category. The potential impacts for each scenario were evaluated using the IMPACT 2002þ LCIA method. The results of the performed LCA indicate that for mine development and operation, scenarios where tailings are partly used as backfill for underground stopes appear to lead to larger impacts in 11 of the 14 midpoint categories since the backfill plant operation consumes a greater amount of material and energy. For a site closure period of 2 years, the CCBE option creates the greatest impacts, since it requires much more effort than the other techniques. The results for the post-closure phase have been analysed separately since they have a larger uncertainty. They appear to modify the comparative assessment results. The various results presented in the paper show the importance of taking land-use impacts into account.

This paper reviews recent advances in the research and development of sorbents used to capture mercury from coal-fired utility boiler flue gas. Mercury emissions are the source of serious health concerns. Worldwide mercury emissions from human activities are estimated to be 1000 to 6000 t/annum. Mercury emissions from coal-fired power plants are believed to be the largest source of anthropogenic mercury emissions.

Solid adsorbents Cu(I) and Ag(I) metal exchanged beta zeolites were prepared by solid-state ion-exchange (SSIE) method. Crystallographic structure of the prepared adsorbents has been characterized by XRD analysis. The texture of the prepared adsorbents was investigated using N 2 sorption. Pyridine IR measurements have been carried out to investigate the nature of the acid sites of the adsorbents. The deep-desulfurization performance of such adsorbents has been evaluated through fixed-bed adsorption technique with model gasoline containing thiophene and benzothiophene at ambient temperature and pressure.

Conferencia presentada en el Foro Taller CYTED Energías Renovables, grandes oportunidades, llevado a cabo en Arequipa, Perú, del 27 al 30 de noviembre de 2018, en la cual se hace una introducción al biogás como combustible gaseoso, producto del procesamiento de la biomasa por medio de la biotecnología anaerobia, se explican los antecedentes y situación actual de la empresa CCA Biogás y se detallan los principales proyectos de biogás desarrollados por la empresa, para su uso como biofertilizante.como combustible para sustituir combustibles fósiles como el Gas Licuado del Petróleo y para producir electricidad, incluyendo el desarrollo de los procesos de eliminación de los compuestos de azufre del biogás,.

This study examines point and non-point sources of air pollution and particulate matter and their associated socioeconomic and health impacts in South Asian countries, primarily India, China, and Pakistan. The legislative frameworks, policy gaps, and targeted solutions are also scrutinized. The major cities in these countries have surpassed the permissible limits defined by WHO for sulfur dioxide, carbon monoxide, particulate matter, and nitrogen dioxide. As a result, they are facing widespread health problems, disabilities, and causalities at extreme events. Populations in these countries are comparatively more prone to air pollution effects because they spend more time in the open air, increasing their likelihood of exposure to air pollutants. The elevated level of air pollutants and their long-term exposure increases the susceptibility to several chronic/acute diseases, i.e., obstructive pulmonary diseases, acute respiratory distress, chronic bronchitis, and emphysema. More in-de...

In order to further reduce the sulfur content in liquid hydrocarbon fuels (gasoline, diesel fuel and jet fuel) for producing ultra-clean transportation fuels and for fuel cell applications, we explored a new desulfurization process by selective adsorption for removing sulfur (SARS). An adsorbent was developed and used for adsorption desulfurization of diesel fuel, gasoline and jet fuel at room temperature. The results indicate that the transition metal-based adsorbent developed in this work is effective for selectively adsorbing the sulfur compounds, even the refractory sulfur compounds in diesel fuels. The SARS process can effectively remove sulfur compounds in the liquid hydrocarbon fuels at ambient temperature under atmospheric pressure with low investment and operating cost. On the basis of the present study, a novel integrated process is proposed for deep desulfurization of the liquid hydrocarbon fuels in a future refinery, which combines a selective adsorption (SARS) of the sulfur compounds and a hydrodesulfurization process of the concentrated sulfur fraction (HDSCS). The SARS concept may be used for on-site or on-board removal of sulfur from fuels for fuel cell systems.

Optimization of the wet limestone (calcite) flue gas desulfurization (FGD) process is described, with the focus on the layout of subprocesses and equipment. The aim of optimization was to check the effectiveness and reliability of alternative layouts, involving intermediate product (gypsum) storage in the absorber make-up tank, instant production of limestone slurry from powder in a wet screw conveyer and automatic gypsum dewatering line operation. Three alternatives, standard layout, optimized layout and optimized layout without reheating of treated gas, were designed and tested in a small industrial FGD plant. The comparison included evaluation of desulfurization efficiency, economical feasibility (considering a 125 MW power plant) and reliability of operation. The efficiency of the system was not affected by the layouts. Investment costs were reduced by 5 and 15 % for alternatives 1 and 2, respectively, compared to standard offers on the market. With respect to operating costs, variable operating and maintenance costs could be decreased by 0.5 up to 2.5 %, respectively. As shown by risk and reliability analysis, the availability of the system in both alternative layouts remained unchanged or was better with regard to the standard layout.

Experimental results of the SO,-Ca(OH), reaction obtained in a laboratory scale fixed-bed reactor under conditions simulating exhausting flue gases from coal-fired plants have been successfully interpreted by means of a shrinking core model with an hyperbolic expression for the influence of gas concentration on the reaction rate. Differential analysis of the experimental data allowed the discrimination between kinetic models reported in the literature which attributed a zero-or first-order dependence to the gas reagent (SO,) on reaction rate and the hyperbolic model presented in this work: k&C, rR =

Aiming for the deep desulfurization of diesel, a novel adsorption-bioregeneration system was constructed by combining adsorption and biodesulfurization processes. The sequence of adsorption capacity of DBT (dibenzothiophene) is AC (activated carbon) > NiY > AgY > alumina > 13X. The sequence of selectivity of DBT toward naphthalene is NiY > AgY > alumina ≈ 13X > AC. For hydrotreated diesel, MAS (mesoporous aluminosilicates) showed high adsorption capacity, while MCM-41 and NaY showed low adsorption capacity. The bioregeneration process of these adsorbents was also carried out with P. delafieldii R-8 cells. Adding P. delafieldii R-8 cells can improve DBT desorption from adsorbents. The desorption of DBT from adsorbents by bioregeneration follows the sequence: 13X > alumina > AgY > NiY > AC. Ag-MAS can be completely regenerated in in situ adsorption-bioregeneration system.

The reaction of methanethiol on ZnO and Cs promoted ZnO surfaces has been studied with synchrotron based photoemission and thermal desorption spectroscopy. On ZnO, methanethiol undergoes selective reaction to produce carbon monoxide (37±58%), methane (23±38%), formaldehyde (12±15%), ethane (1±11%), and a mixture of ethylene and acetylene (3±13%). At low temperatures (<100 K), methanethiol reacts to yield thiolate intermediate bound to Zn 2 cations. The thiolate is stable to 500 K. Above this temperature, C±S bond cleavage occurs to yield methyl intermediate and atomic S. Carbon is removed from the surface as gaseous products above 500 K, and atomic sulfur remains bound to the zinc sites of the surface. Submonolayer amounts of cesium do not have a signi®cant promotional eect on C±S bond cleavage, whereas Cs multilayers are found to signi®cantly lower the activation barrier for C±S bond cleavage. This study illustrates the chemistry associated with the desulfurization of thiols on a catalytically relevant oxide surface. Ó (J.A. Rodriguez). 0039-6028/01/$ -see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 0 3 9 -6 0 2 8 ( 0 1 ) 0 0 9 7 3 -6

This report summarizes the accomplishments toward project goals during the first six months of the second year of the project to assess the properties and performance of coal based products. These products are in the gasoline, diesel and fuel oil range and result from coal based jet fuel production from an Air Force funded program. Specific areas of progress include generation of coal based material that has been fractionated into the desired refinery cuts, acquisition and installation of a research gasoline engine, and modification of diesel engines for use in evaluating diesel produced in the project. The desulfurization of sulfur containing components of coal and petroleum is being studied so that effective conversion of blended coal and petroleum streams can be efficiently converted to useful refinery products. Evaluations to assess the quality of coal based fuel oil are reported. Coal samples have procured and are being assessed for cleaning prior to use in coking studies. iv