Energy saving in a crude distillation unit by a preflash implementation

After the 70s energy crisis the revamping of plants designed before this date is very attractive for improving energy recovery and lowering operation costs.A typical case is the oil refinery plant where an intensive usage of energy takes place and is a promising case for the application of energy saving solutions. In this work we focused our attention to an industrial crude oil distillation unit, evaluating the possibility to modify the feed conditions by installing a preflash drum or a preflash plate column.Real data plant were collected to obtain a reliable simulation of the unit by means of the software package Aspen Plus 13.0. To characterize the crude oil fed the TBP curve was used. The results obtained were compared with the plant data in terms of flow rate and product quality utilizing the ASTM D-86 curves and a good agreement was obtained. According to the specialized literature the preflash drum/column was placed at the end of the pre-heat train, just before the column furnace.The furnace is the bottleneck of the plant and with both the preflash devices it is possible to lower its energy consumption. However the energy reduction is associated to the decrease of one kind of distillates (light or middle). The choice of the best preflash device was made according to the production asset of the plant.     

Development of a porous burner unit for glycerine utilization from biodiesel production by Supercritical Water Reforming

In the production of biodiesel from vegetable oils, glycerine is produced as a by-product, yielding an amount of about 10 percent of the quantity of biodiesel produced. The glycerine-market is saturated by the growing biodiesel production, so that an alternative use of glycerine is sought. An alternative is the conversion of glycerine into a hydrogen-rich synthesis gas through the procedure of Supercritical Water Reforming (SCWR), from which other energy conversion processes can be made. In the present project, inter alia a porous burner is meant to be used as a heat source for the reforming. This burner technology allows an effective and low-emission combustion of different fuels in a high performance modulation. By individual adjustment, the burner is meant to burn the generated hydrogen-rich synthesis gas and glycerine.     

Hydrogen energy production using manganese/semiconductor system inspired by photosynthesis

Hydrogen is the most efficient and the cleanest fuel. Inspired by photosynthesis, which is able to catalyze water-splitting reaction to achieve energy storage on the large scale at room temperature and neutral pH in nature, artificial systems and technology have been increasing advanced and great progresses have been made over the past decades. The three-dimensional structure of photosystem II with oxygen-evolving activity has been determined at an atomic level, which provides a thorough image with the specific position of each atom in the Mn₄CaO₅ cluster. These advancements have significantly enhanced our understanding of the mechanisms of water splitting in photosynthesis and offered a unique opportunity for hydrogen fuel production. In this review, the recent efforts in the area of manganese/semiconductor system for hydrogen generation were summarized with examples and discussed to highlight the operation mechanisms of this kind of catalytic configuration. A robust PS II mimic containing manganese/semiconductor nanostructure to accomplish the photo water splitting chemistry was evaluated. The development, mechanism, and future improvement of the manganese/semiconductor system were presented. The manganese/semiconductor system is highly likely to offer novel technology for hydrogen energy production.     

Exergoeconomic analysis of a hybrid copper-chlorine cycle driven by geothermal energy for hydrogen production

In this study, we conduct an exergy, cost, energy and mass (EXCEM) analysis of a copper-chlorine thermochemical water splitting cycle driven by geothermal energy for hydrogen production. We also investigate and illustrate the relations between thermodynamic losses and capital costs. The results show that hydrogen cost is closely and directly related to the plant capacity and also exergy efficiency. Increasing economic viability and reducing the hydrogen production costs will help these cycles play a more critical role in switching to hydrogen economy.     

Thermo-economic analysis of a hydrogen production system by sodium borohydride (NaBH4)

In the spectrum of current energy possibilities, hydrogen represents a solution of great interest toward a future sustainable energy system. No single technology can sustain the energy needs of the whole society, but integration and hybridization are two key strategic features for viable energy production based in hydrogen economy.In the present work, a hydrogen energy model is analyzed. In this model hydrogen is produced through the electrolysis of water, taking advantage of the electrical energy produced by a renewable generator (photovoltaic panels). The produced hydrogen is chemically stored by the synthesis of sodium borohydride (NaBH₄). NaBH₄ promising features in terms of safety and high volumetric density are exploited for transportation to a remote site where hydrogen is released from NaBH₄ hydrolysis and used for energy production.This model is compared from an economic standpoint with the traditional hydrogen storage and transportation technology (compressed hydrogen in tanks).This paper presents a thermodynamic and economic analysis of the process in order to determine its economic feasibility. Data employed for the realization of the model have been gathered from recent important progresses made on the subject.The innovative plant including NaBH₄ synthesis and transportation is compared from an economic standpoint with the traditional hydrogen storage and transportation technology (compressed hydrogen in tanks). As a final point, the best technology and the components' optimal sizes are evaluated for both cases in order to minimize production costs.     

A perspective on possible amendments in semiconductors for enhanced photocatalytic hydrogen generation by water splitting

Photocatalytic hydrogen production using solar irradiation is the best solution for existing energy crisis and ecological issues. Various efforts have been made to design a stable, proficient and visible light driven photocatalyst for hydrogen generation. It has been revealed that numerous factors e.g., surface area, morphology, band structure, charge transference and crystallinity affect the solar to hydrogen conversion ability of photocatalyst. Currently, many modification strategies including anion/cation doping, composite formation and alloy fabrication have been advised for semiconductor catalysts to harvest solar light to maximum extent. Moreover, a progression of novel engineering techniques that introduces dye sensitizers, quantum dots and co-catalysts, seems to enhance the photocatalytic efficiency for hydrogen production. In this perspective, we present a summary of various factors that can enhance the effectiveness of hydrogen generation and outline current advancement of frequently used fabricating strategies that look for greater yield of hydrogen. Lastly, emergence of surface plasmon resonance and significance of photocatalyst recycling for hydrogen generation is discussed. It is expected that this perspective will help researchers in designing an efficient photocatalyst for industrial scale hydrogen production.     

Performance analysis of a solar chimney power plant in the southwestern region of Algeria

In this paper, we present the performance analysis of a solar chimney power plant expected to provide the remote villages located in Algerian southwestern region with electric power. Solar energy and the psychometric state of the air in the south of Algeria are important to encourage the full development of solar chimney power plant for the thermal and electrical production of energy for various uses. We are interested in Adrar where solar radiation is better than other areas of Algeria. The obtained results show that the solar chimney power plant can produce from 140 to 200 kW of electricity on a site like Adrar during the year, according to an estimate made on the monthly average of sunning. This production is sufficient for the needs of the isolated areas.     

Assessment of potential biomass energy production in China towards 2030 and 2050

The objective of this paper is to provide a more detailed picture of potential biomass energy production in the Chinese energy system towards 2030 and 2050. Biomass for bioenergy feedstocks comes from five sources, which are agricultural crop residues, forest residues and industrial wood waste, energy crops and woody crops, animal manure, and municipal solid waste. The potential biomass production is predicted based on the resource availability. In the process of identifying biomass resources production, assumptions are made regarding arable land, marginal land, crops yields, forest growth rate, and meat consumption and waste production. Four scenarios were designed to describe the potential biomass energy production to elaborate the role of biomass energy in the Chinese energy system in 2030. The assessment shows that under certain restrictions on land availability, the maximum potential biomass energy productions are estimated to be 18,833 and 24,901?PJ in 2030 and 2050.     

Potential energy savings by application of the novel CRIMSON aluminium casting process

Compared with its output the casting industry uses a disproportionate amount of energy as a result of the inefficient processes used. This paper presents the melting processes that are used in one of the traditional foundries and identifies the energy burdens associated with them. A comparison is then made with the new CRIMSON process to demonstrate where energy savings can be made. An actual case or casting sample is investigated to demonstrate the advantage of energy saving in CRIMSON method which will help the foundry industry in reduction of energy cost and promote competitiveness in the production of high end casting components.     

Preparation of hydrogen from metals and water without CO2 emissions

Considering the high calorific value and low-carbon characteristics of hydrogen energy, it will play an important role in replacing fossil energy sources. The production of hydrogen from renewable energy sources for electricity generation and electrolysis of water is an important process to obtain green hydrogen compared with classic low-carbon hydrogen production methods. However, the challenges in this process include the high cost of liquefied hydrogen and the difficulty of storing hydrogen on a large scale. In this paper, we propose a new route for hydrogen storage in metals, namely, electricity generation from renewable energy sources, electrolysis to obtain metals, and subsequent hydrogen production from metals and water. Metal monomers facilitate large-scale and long-term storage and transportation, and metals can be used as large-scale hydrogen storage carriers in the future. In this technical route, the reaction between metal and water for hydrogen production is an important link. In this paper, we systematically summarize the research progress, development trend, and challenges in the field of metal to hydrogen production. This study aim to aid in the development of this field.     

Use of hydrogen produced by the air conversion of motor diesel fuel in an electrochemical generator

At present, the production of electric energy consumer remote from agro-based centralized networks is done using diesel-generator technology with limited service life of the engine and the extremely low efficiency in the use of expensive fuel. In this paper, is considered an innovative technology of combined production of electricity and heat using a preliminary conversion of diesel fuel in the synthesis gas and then serving it at high temperature electrochemical generator. Synthetic gas to operate the generator air conversion is made of an electrochemical engine diesel fuels in catalytic reactor-burner. On the basis of heat balances of the torch, battery power and boiler are calculated: battery electric efficiency SOFC, chemical efficiency burner, SOFC anode temperature, EMF Planar element, the proportion of hydrogen, oxidized anode SOFC, unit cost of diesel fuel for the production of electricity and thermal energy. Specific consumption of diesel fuel for the production of electrical energy 114 g/kWh (162 g. w. t./kWh), and thermal 31.7 kg/Gj (45.1 kg/GJ, w. t. 189 kg standard fuel/Gcal).     

Advances in hydrogen production by thermochemical water decomposition: A review

Hydrogen demand as an energy currency is anticipated to rise significantly in the future, with the emergence of a hydrogen economy. Hydrogen production is a key component of a hydrogen economy. Several production processes are commercially available, while others are under development including thermochemical water decomposition, which has numerous advantages over other hydrogen production processes. Recent advances in hydrogen production by thermochemical water decomposition are reviewed here. Hydrogen production from non-fossil energy sources such as nuclear and solar is emphasized, as are efforts to lower the temperatures required in thermochemical cycles so as to expand the range of potential heat supplies. Limiting efficiencies are explained and the need to apply exergy analysis is illustrated. The copper–chlorine thermochemical cycle is considered as a case study. It is concluded that developments of improved processes for hydrogen production via thermochemical water decomposition are likely to continue, thermochemical hydrogen production using such non-fossil energy will likely become commercial, and improved efficiencies are expected to be obtained with advanced methodologies like exergy analysis. Although numerous advances have been made on sulphur–iodine cycles, the copper–chlorine cycle has significant potential due to its requirement for process heat at lower temperatures than most other thermochemical processes.     

Conversion of jet fuel and butanol to syngas by filtration combustion

Replacing batteries with fuel cells is a promising approach for powering portable devices; however, hydrogen fuel generation and storage are challenges to the acceptance of this technology. A potential solution to this problem is on-site fuel reforming, in which a rich fuel/air mixture is converted to a hydrogen-rich syngas. In this paper, we present experimental results of the conversion of jet fuel (Jet-A) and butanol to syngas by non-catalytic filtration combustion in a porous media reactor operating over a wide range of equivalence ratios and inlet velocities. Since the focus of this study is the production of syngas, our primary results are the hydrogen yield, the carbon monoxide yield, and the energy conversion efficiency. In addition, the production of soot that occurred during testing is discussed for both fuels. Finally, an analysis of the potential for these fuels and others to be converted to syngas based on the present experiments and data available in the literature is presented. This study is intended to increase the understanding of filtration combustion for syngas production and to illuminate the potential of these fuels for conversion to syngas by non-catalytic methods.     

Pricing the (European) option to switch between two energy sources: An application to crude oil and natural gas

We consider a firm, which can choose between crude oil and natural gas to run its business. The firm selects the energy source, which minimizes its energy or production costs at a given time horizon. Assuming the energy strategy to be established over a fixed time window, the energy choice decision will be made at a given future date T. In this light, the firm's energy cost can be considered as a long position in a risk-free bond by an amount of the terminal oil price, and a short position in a European put option to switch from oil to gas by an amount of the terminal oil price too. As a result, the option to switch from crude oil to natural gas allows for establishing a hedging strategy with respect to energy costs. Modeling stochastically the underlying asset of the European put, we propose a valuation formula of the option to switch and calibrate the pricing formula to empirical data on a daily basis. Hence, our innovative framework handles widely the hedge against the price increase of any given energy source versus the price of another competing energy source (i.e. minimizing energy costs). Moreover, we provide a price for the cost-reducing effect of the capability to switch from one energy source to another one (i.e. hedging energy price risk).     

A model for industrial production of fuel grade ethanol from sugar beets

In this work we describe a model for industrial production of low cost ethanol from sugar beets. Care is taken to cover the energy needs of the factory in part by using dry pulp as fuel and in part by solar energy, using suitable solar collectors. Also, care is taken for recovery of rejected energy of vinasse, and we propose the use of one distillation column, instead of three column distillation plants which are used for the production of pure ethanol. A method of high fermentation rate, for reduction of cost, is proposed, and the rejected yeast per day from Laval separators. is processed as an animal protein food (8 kg pressed yeast per 1001 spirit). The mass and energy balance is given and a cost analysis of spirit production in current prices. This cost is 25.0 Dr or $0.50 per 1 (1$ - 50 Dr).     

The potential of water power in the fight against global warming in the US

The leading cause of climate change today is the burning of fossil fuels related to energy production. One approach to reducing greenhouse gas emissions, therefore, is to more actively switch to renewable technologies in the production of electricity, and reduce the use of fossil fuels in electricity production. This is the goal of renewable portfolio standard (RPS) legislation, currently in effect in 28 states across the country. In this paper we discuss the potential for water power development as one method to reduce US greenhouse gas emissions. We look at the potential from (1) new small/micro hydropower dams, (2) uprating facilities at existing large hydropower dams, (3) new generating facilities at existing non-hydropower dams, and (4) hydrokinetics. We analyze this potential by type, by state, and by its ability to satisfy current RPS goals. Finally, we consider the cost-effectiveness of developing these sources of water-based energy. We find that while water power will never be the complete answer to emissions-free energy production, a strong case can be made that it can be a useful part of the answer.     

Regional energy rebound effect: The impact of economy-wide and sector level energy efficiency improvement in Georgia,USA

Rebound effect is defined as the lost part of ceteris paribus energy savings from improvements on energy efficiency. In this paper, we investigate economy-wide energy rebound effects by developing a computable general equilibrium (CGE) model for Georgia, USA. The model adopts a highly disaggregated sector profile and highlights the substitution possibilities between different energy sources in the production structure. These two features allow us to better characterize the change in energy use in face of an efficiency shock, and to explore in detail how a sector-level shock propagates throughout the economic structure to generate aggregate impacts. We find that with economy-wide energy efficiency improvement on the production side, economy-wide rebound is moderate. Energy price levels fall very slightly, yet sectors respond to these changing prices quite differently in terms of local production and demand. Energy efficiency improvements in particular sectors (epicenters) induce quite different economy-wide impacts. In general, we expect large rebound if the epicenter sector is an energy production sector, a direct upstream/downstream sector of energy production sectors, a transportation sector or a sector with high production elasticity. Our analysis offers valuable insights for policy makers aiming to achieve energy conservation through increasing energy efficiency.     

Hydrogen production by coupling pressurized high temperature electrolyser with solar tower technology

Solar hydrogen production by coupling of pressurized high temperature electrolyser with concentrated solar tower technology is studied. As the high temperature electrolyser requires constant temperature conditions, the focus is made on a molten salt solar tower due to its high storage capacity. A flowsheet was developed and simulations were carried out with Aspen Plus 8.4 software for MW-scale hydrogen production plants. The solar part was laid out with HFLCAL software. Two different scenarios were considered: the first concerns the production of 400 kg/d hydrogen corresponding to mobility use (fuel station). The second scenario deals with the production of 4000 kg/d hydrogen for industrial use. The process was analyzed from a thermodynamic point of view by calculating the overall process efficiency and determining the annual production. It was assumed that a fixed hydrogen demand exists in the two cases and it was assessed to which extent this can be supplied by the solar high temperature electrolysis process including thermal storage as well as hydrogen storage. For time periods with a potential over supply of hydrogen, it was considered that the excess energy is sold as electricity to the grid. For time periods where the hydrogen demand cannot be fully supplied, electricity consumption from the grid was considered. It was assessed which solar multiple is appropriate to achieve low consumption of grid electricity and low excess energy. It is shown that the consumption of grid electricity is reduced for increasing solar multiple but the efficiency is also reduced. At a solar multiple of 3.0 an annual solar-to-H₂ efficiency greater than 14% is achieved at grid electricity production below 5% for the industrial case (4000 kg/d). In a sensitivity study the paramount importance of electrolyser performance, i.e. efficiency and conversion, is shown.     

Linseed oil as a potential resource for bio-diesel: A review

The energy crisis contributed to the development of bio-diesel production. Petroleum, charcoal and natural gas sources are limited and will be exhausted by the next century. Thus, looking for alternative source of energy is of vital importance Vegetable oils are a renewable and potentially inexhaustible source of energy with an energetic content close to diesel fuel. In recent years, bio-diesel has become more attractive as an alternative fuels for diesel engine because of its environmental benefits and it is made from renewable resource. Since edible oil demand is higher than its domestic production; there is no possibility of diverting this oil for production of bio-diesel in India. Being a tropical country, India is rich in forest resources having a wide range of trees, which yield a significant quantity of oilseeds. India is importing crude petroleum & petroleum products from Gulf countries. Indian scientists searched for an alternate to diesel fuel to preserve global environment and to withstand economical crisis. This review paper describes the production of linseed oil, its properties, composition and future potential for bio-diesel. Linseed plant contains high amount of oil in its seeds which can be converted to bio-diesel. Fatty acid compositions of linseed reported in literature are provided in this review. In this study the properties of methyl ester of linseed oil are compared with the properties of fossil diesel. The objective of this review is to give an update on the linseed plant, the production of bio-diesel from the linseed oil and research attempts to improve the technology of converting linseed oil to bio-diesel and the fuel properties of linseed bio-diesel. The technological methods that can be used to produce bio-diesel are presented together with their advantage and disadvantages. Many other areas that need to be researched on linseed oil are pointed out in this review.     

Economic analysis of renewable heat and electricity production by sewage sludge digestion—a case study

In this paper, we assess the total cost of energy recovery from sewage sludge through anaerobic digestion with biogas utilization in combined heat and power (CHP) system. The important advantage of anaerobic digestion process is the production of biogas, which can be used to generate electricity and heat as a source of renewable energy. From this study, it can be retained that the generated thermal energy from the anaerobic digestion process meets the needs of the wastewater treatment plant (WWTP) and guarantees its self‐sufficiency in heat. The surplus of renewable heat produced by CHP is not a primary factor to improve the economic viability of the process. Moreover, the sales of electricity output represent about 76% of the operating costs of anaerobic digestion process. Renewable energy production is not economically viable by its own, without considering the wastewater treatment function and the associated incomes. Nevertheless, sludge digestion helps to reduce the wastewater treatment costs mainly by giving a good source of revenue via electricity production. Copyright © 2014 John Wiley & Sons, Ltd.