Membrane for Water and Energy Engineering

A University of Brawijaya Lecturer Weblog by Yusuf Wibisono, S.TP., M.Sc.

Theory of porous media

March 9, 2010 No comments

In the mid-19th century, the theory of porous media were unknown, it was a long vacuum since the development of volume fractions by Woltman in 1794. However, the fundamental discoveries were found by Delesse, Fick and Darcy. Delesse develop the concept of surface fraction in 1848, Fick studied the problem of diffusion through membrane in 1855, and then Darcy in 1856 investigated the permeability of water running through sand as a basic study in multiphase continuum [1].

The Darcy equation actually was derived from the Navier-Stokes equation by assuming stationary, creeping, incompressible flow through porous medium. Since the Darcy’s equation becomes invalid for liquid for high velocity, or gases for very low or very high velocities, the corrections was build by Brinkmann. Brinkman’s filtration equation is usually used to describe the low-Reynolds-number flow in porous media in situations where velocity gradients are non-negligible [2].

References:

  1. R. de Boer, Theory of porous media: Highlights in the historical development and current state, Springer-Verlag, Berlin-Heidelberg, 2000.
  2. F. J. Valdes-Parada, J. A. Ochoa-Tapia, and J. Alavarez-Ramirez, On the effective viscosity for the Darcy-Brinkmann equation, Physica A, 2007, 385, 69-79.
Mathematics

Navier-Stokes equations

March 9, 2010 1 comment

The viscous fluids theory is marked by the Navier-Stokes equations, that’s named after Claude-Louis Navier and George Gabriel Stokes, applying Newton’s idea written in his Philosophiae naturalis principia mathematica in which describing the motion of mass point and Euler’s equations in his Mechanica in which formulated the axioms of continuum mechanics, that is: the balance of mass, the balance of momentum, the balance of moment of momentum, and the cut principle. The historical development of Navier-Stokes equations was based on the Newton’s hypothesis that notices that the motion of fluid past other bodies is held back by friction. Navier introduces both types of friction into the equations of motions, for the material points inside as well as on the boundary in his Memoir sur les lois du movement des fluids. This work was continued by Poisson, De Saint-Venant, and finally by Stokes [1].

Stokes briefly explained his theory of fluid motion in various initials and boundary conditions in Transactions of the Cambridge Philosophical Society and Cambridge Mathematical Journal, and describe in On the steady motion of incompressible fluids in 1842. He also wrote about flow in cylindrical coordinate in On the motion of a piston and of the air in a cylinder in 1843 [2]. The development of this equation was built more than 150 years, however a fundamental problem is to decide whether such smooth, physically reasonable solutions exist for the Navier-Stokes equations. It is make the Navier-Stokes equations is one of seven unsolved mathematical problems in this millennium [3].

References:

  1. R. de Boer, Theory of porous media: Highlights in the historical development and current state, Springer-Verlag, Berlin-Heidelberg, 2000.
  2. G. G. Stokes, Mathematical and physical papers, Cambridge University Press, Cambridge, 1880.
  3. K. J. Devlin, The millennium problems: The seven greatest unsolved mathematical puzzles of our time, Basic Books, 2002.
Mathematics ,

Inorganic membrane

March 2, 2010 No comments

The membrane separation process can be packaged in one of four common integrated arrangements that called membrane modules: plate and frame, spiral wound, hollow fiber, capillary and tubular [1]. Both plate and frame and spiral wound modules, the flat sheet membrane is used. In the case of plate and frame modules, the membrane sheets are simply attached frames which are stacked together in such a fashion that a feed flow channel is formed between the frames. Plate and frame modules suffer from the fact that the packing density, or the amount of membrane area which can be packed into a given volume, is quite low and the manufacturing costs tend to be high. Spiral wound elements neatly address both these problems. In this modules, two membrane sheets are placed back to back separated by a permeate spacer and sealed with glue on three sides. Then, the remaining side is connected to a porous permeate tube which runs through the centre of the completed module. Finally, a feed spacer is placed adjacent to each active membrane surface and the membrane sheet is rolled around the permeate tube to create a cylindrical module. The feed spacers create feed channels by insuring that the rolled up membrane do not contact each other while the permeate spacers provide a spiral path for the permeate to reach the central tube [2].

The other common used membrane module is the tubular membrane. The membrane belonging to this group all have a tubular shape (high ratio of length to diameter). The length is ranging from one to three meter and the diameter of the membrane is ranging from half a millimeter to two centimeter. Tubular membranes with a diameter below than 0.5 mm are called hollow fiber membranes, ones with the diameter ranging from 0.5 to 5 mm are called capillary membranes, while membrane with a diameter larger than 5 mm a called tubular membrane. Tubular membranes are made by casting a membrane onto porous supporting tubes. These supporting tubes are manufactured from fiber glass, ceramics, carbon, porous plastics, stainless steel or paper and must be strong enough to withstand the feed pressures [3].

The advantages of inorganic membranes compares with organic membranes have been recognized i.e.: thermal and pH resistances, generally can withstand organic solvents, chlorine and other corrosive chemicals (see Figure 1.3). Most of inorganic membrane have multi-layered structure and consist of the separating layer and the underlying support layer(s). The available filtration area per unit per volume of support varies from 300 to 2,000 m2/m3. Each layer contains different pore size and porosity. The support, made of alumina, zirconia, titania, silica, spinel, aluminosilicate, cordierite or carbon, typically has a pore diameter of about 1 to 20 mm and a porosity of 30 to 60%. Any additional intermediate support layers have progressively smaller pore size than the underlayer of support. The intermediate support layers are typically 20-60 mm in thickness and 30-40% in porosity. The selective membrane material varies from alumina, zirconia, glass, titania, cordierite, mullite, carbon to such metals as stainless steel, palladium and silver. The overall membrane element shape comes in different types: sheet, single tube, hollow fiber and multi-channel monolith. A monolithic multi-channel honeycomb shape provides more filtration area per unit volume than either a sheet or a single tube [4].

References:

  1. R. Rautenbach and R. Albrecht, Membrane Processes, John Wiley and Sons, Ltd., Chichester, 1989, 459 pp.
  2. J. G. Pharoah, Fluid dynamics and mass transport in rotating channels with application to centrifugal membrane separation, PhD Dissertation, University of Victoria, 2002.
  3. J. Q. J. C. Verbeck, Application of air in membrane filtration, PhD Dissertation, Technische Universiteit Delft, 2005.
  4. H. P. Hsieh, Inorganic membranes for separation and reaction, Membrane Science and Technology Series 3, Elsevier Science B.V., Amsterdam, 1996, 591 pp.
Membrane

Basic principle of membrane filtration

March 2, 2010 No comments

Filtration is convective discriminating mass transport of liquid mixtures or gaseous dispersions (aerosols) through porous barriers, mass transport ideally being confined to the void space of the barriers. Membrane filtration, accordingly, is pressure driven barrier separation of aqueous solutions, loosely grouped into a number of process variants with reference to the size brackets of the solutes handled:  nanofiltration (NF) 0.01−0.001 μm (<10nm), ultrafiltration (UF) 0.2−0.005 μm (5−200nm) and microfiltration (MF) 10−0.1 μm (>100nm) [1]. The artificial membrane as a barrier differs to a wide variety, like polymer, ceramic, metal and liquid based materials, microporous and dense membrane based structure characteristics, or symmetric and anisotropic refers to the distribution of the pores. Membrane filtration is the surface or screening removal that differs from depth filtration [2]. Filtration operations are performed in one of two modes: tangential flow filtration (TFF) or normal flow filtration (NFF), with the latter commonly called cross-flow filtration and dead-end filtration. Viscous feed suspensions or ones that have high particulate concentrations are typically processed by cross-flow filtration to reduce the accumulation of retained material at the membrane surface, while dead-end filtration tends to be used for more dilute suspensions or smaller batch sizes [3].

References:

  1. K. W. Böddeker, Liquid separations with membranes, an introduction to barrier interference. Spriger-Verlag Berlin Heidelberg, 2008, 146 pp.
  2. M. Cheryan, Ultrafiltration Handbook, Technomic Publishing Company, Inc., Pennsylvania, 1986.
  3. M. A. Chandler, Fouling mechanisms during depth and membrane filtration of yeast cell suspensions, PhD Thesis, The Pennsylvania State University, 2006.
Membrane

Before using biooil in diesel engines

March 2, 2010 No comments

In 1876, Nikolaus August Otto developed a stationary, single-cylinder, four-stroke engine that ran on coal gas. The basic principle of spark ignition (Otto) engine, a combustion engine with timed ignition from an external source, can be realized in a number of variants with different types of fuel metering and mixture preparations. The diesel engine, patented in 1892 by Rudolf Diesel, differs from the Otto engine in the heterogeneous composition of its mixture and characterized by self-ignition of the fuel. Self-ignition is achieved by compressing the incoming air to such an extent that resulting temperature increase is sufficient to ignite the fuel [1].

Both of the inventors use liquid fuel to run the engines. Otto conceived his invention to run on ethanol, while Diesel used 100% peanut oil (the “original” biodiesel) in the first demonstration of his compression ignition engine at the World’s Exhibition in Paris. Diesel recognized at the turn of this century that vegetable-based fuels would work in his engines. In 1911 he stated ‘‘The diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture of the countries, which use it’’. In 1912, Diesel said, ‘‘The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time’’[2]. Vegetable oils were used in diesel engines until the 1920’s when an alteration was made to the engine, enabling it to use a residue of petroleum (currently known as No. 2 diesel fuel). Nevertheless, Diesel was not the only person to believe that biofuels could be the way forward of the transportation industry. Henry Ford was so convinced that renewable resources were the key to the success of his automobiles that he designed them (from the 1908 Model T) to be run with ethanol.

Three different approaches to using vegetable oils as diesel fuels have been identified and tested: pure vegetable oils, esterified vegetable oils, and blends of oils or esters with diesel fuel. Transesterification is basically a sequential reaction. Triglycerides are first reduced to diglycerides. The diglycerides are subsequently reduced to monoglycerides. The monoglycerides are finally reduced to fatty acid esters [3].

Preliminary studies indicate that, over short periods of time, 100% vegetable oil fuels perform satisfactorily in unmodified diesel engines. This is true for several major indicators of performance, including power output, torque, brake thermal efficiency and fuel consumption for a number of different vegetable oils in a number of different makes and models of diesel engines. Esterified vegetable oils have produced slightly better short-run performance results. Blends of oils or their esters with diesel fuel have given results more similar to pure diesel fuel, with smaller proportions of oils performing somewhat better than blends with high proportions. The short-term success in using unblended vegetable oils as a diesel fuel has been accompanied by problems. These problems may be divided into two broad classes. The first includes those involved with daily short-term use, and the second involves those resulting from long-term continuous use of vegetable oils. Several short-term problems include some difficulty with cold starts; plugging and gumming of filters, lines and injectors; and engine knocking. Researchers have correlated these with several basic properties of vegetable oils, such as naturally occurring gums; high viscosity; acid composition; free fatty acid content; and low cetane rating. Crude vegetable oils contain gumming materials called phosphatides. The trash and gums may collect and clog the fuel filter, lines and injectors. The free fatty acid component of vegetable oils can be harmful to engines. These acids can cause corrosion in the fuel system, fuel injectors, piston and cylinders and the crankcase (see Table 1.5) [4].

Phospholipids or phospatides which include the compound phosphatidylcholine, the chemical term for lecithin, are lipids containing a phosphoric acid residue, they are nature’s principal surface active agents, and they found in all living cells, whether of animal or plant origin. In humans and animals, the phosphatides are concentrated in the vital organs, such as the brain, liver, and kidney; while in vegetables they are highest in the seeds, nuts, and grains [5]. Although blending of oils and other solvents and microemulsions of vegetable oils lowers the viscosity, engine performance problems, such as carbon deposit and lubricating oil contamination, still exist [3]. Virtually all experts recommend degumming vegetable oil for fuel use.

Table 1.5. Known problems, probable causes and potential solutions for using straight vegetable oils in diesels [4].

Problem Probable cause Potential solution
Short term
1 Cold weather starting High viscosity, low cetane, and low flash point of vegetable oils Preheat fuel prior to injection. Chemically alter fuel to an ester.
2 Plugging and gumming of filters, lines and injectors Natural gums (phosphatides) in vegetable oil. Other ash. Partially refine the oil to remove gums. Filter oil to 4 microns.
3 Engine knocking Very low cetane of some oils. Improper injection timing. Adjust injection timing. Use higher compression engines. Same as (1).
Long term
4 Coking of injector nozzles High viscosity of vegetable oil, incomplete combustion of fuel. Poor combustion at part load with vegetable oils. Heat fuel prior to injection. Switch engine to diesel fuel when operating at part load. Chemically alter the vegetable oil to an ester.
5 Carbon deposits on piston and head of engine Same as (4) Same as (4)
6 Excessive engine wear Same as (4). Possibly free fatty acids in vegetable oil. Dilution of engine lubricating oil due to blow-by of vegetable oil. Same as (4). Increase motor oil changes. Motor oil additives to inhibit oxidation.
7 Failure of engine lubricating oil due to polymerization Collection of polyunsaturated vegetable oil blow-by in crankcase to the point where polymerization occurs. Same as (4) and (6). Use vegetable oils low in polyunsaturates.

The terms degumming and desliming are used to refer to refining treatments designed to remove phosphatides and certain other ill-defined “slimes” or “mucilaginous materials” from the oil but do not significantly reduce the acidity of the oil [6]. Oil refining processes commonly have one or more stages during which phospatides are removed from the oil. These stages can be separated treatments such as: water degumming by treating crude oil with hot water or steam; acid degumming by using a degumming acid instead of water; and acid refining, whereby crude or water-degummed oil is treated with a degumming acid that is subsequently partially neutralized. They can also be combined with other refining steps such as: dry degumming where degumming is combined with bleaching; and alkali refining where degumming is combined with the chemical neutralization of the oil. Also, enzymatic-degumming process that has reached pilot plant stage [7].

Additionally, the process of ultrafiltration of edible oil miscella is presented as a novel development, which fulfills the requirements for physical refining very efficiently. The ultrafiltration process, which exploits the principle of reversed osmosis, removes phospholipids and other numerous impurities present in crude oils in one single unit-process [8]. Degumming by UF has also been the subject of several patent applications; Austrian Patent (356228) US Patents (4093540 and 4414157) and a UK Patent (2118568A) [9]. This is called by membrane degumming technology [10]. Gums are phospholipids which can be removed by adding water to the crude vegetable oil, then hydrating and settling or separating them using centrifugation. In contrast, membrane de-gumming can be done with the miscella itself. Being amphiphilic, the phosphatides form reverse micelles in the miscella with molecular weights exceeding 20 000 daltons, and molecular sizes of 20–200 nm. Thus, UF could be used to separate them from the oil-hexane mixture. Permeate consists of hexane, triglycerides, FFAs and other small molecules, while almost all the phospholipids are retained by the membrane [11].

References:

  1. W. Dabelstein, A. Reglitzky, A. Schütze, and K. Reders, Automotive fuels,  In: B. Elvers (eds.), Handbook of fuels: Energy sources for transportation, Wiley-VCH verlag GmbH and Co. KGaA, Weinheim, 2008, 97-195.
  2. A. K. Agarwal, Biofuels (alcohols and biodiesel) applications as fuels for internal combustion engines, Progress in Energy and Combustion Science, 2007, 33, 233-271.
  3. F. R. Ma and M. A. Hanna, Biodiesel production: a review, Bioresources Technology, 1999, 70, 1-15.
  4. H. J. Harwood, Oleochemicals as a fuel: Mechanical and economic feasibility, JAOCS, 1984, 61 (2), 315-324.
  5. E. F. Sipos and B. F. Szuhaj, Lechitins, In: Y. H. Hui (eds.), Bailey’s industrial oil and fat products 5th edition, Volume 1 Edible oil and fat products: General Applications, A Wiley-Interscience Publication, John Wiley and Sons, Inc., New York, 1996, 311-395.
  6. A. S. Hodgson, Refining and bleaching, In: Y. H. Hui (eds.), Bailey’s industrial oil and fat products 5th edition, Volume 4 Edible oil and fat products: Processing technology, A Wiley-Interscience Publication, John Wiley and Sons, Inc., New York, 1996, 157-212.
  7. A. J. Dijkstra, Degumming, refining, washing and drying fats and oils, In: T. H. Applewhite, Proceedings of the World Conference on Oilseed Technology and Utilization, The American Oil Chemists Society, 1993, 138-151.
  8. A. K. Sen Gupta, Neuere Entwicklungen auf dem Gebiet der Raffination der Speiseöle, Fette.Seifen.Anstrichmittel., 1984, 88 (3), 79-86.
  9. J. B. Snape and M. Nakajima, Processing of agricultural fats and oils using membrane technology, Journal of Food Engineering, 1996, 30, 1-41.
  10. J. Cmolik and J. Pokorny, Physical refining of edible oils, Eur. J. Lipid Sci. Technol., 2000, 102, 472-486.
  11. M. Cheryan, Membrane technology in the vegetable oil industry, Membrane Technology, 2005, 2, 5-7.
Energy , ,

Jatropha curcas: an overview

March 2, 2010 No comments

Consider the food or energy crops priority, it is important to choose the suitable energy crops converting to biofuels. Corn has become the very emblem of plenty, with rich golden cobs of corn overspilling from some of the most effectively farmed arable lands on the earth. Jatropha curcas, on the other hand, is an unprepossessing and indeed toxic plant, better suited to scrubland and hedges. Yet in the world of biofuels, ugly-duckling jatropha has the potential to be, if not a hero, and a harbinger of better things to come [1].

Jatropha curcas L. is a drought-resistant shrub or tree belonging to the genus Euphorbiaceae, which is cultivated in Central and South America, South-east Asia, India and Africa [2]. J. curcas is easy to establish, grows relatively quickly and is hardy, being drought tolerant. It is not browsed, for its leaves and stems are toxic to animals, but after treatment, the seeds or seed cake could be used as an animal feed. J. curcas meals contain high true protein, high energy and low fiber [3]. Various parts of the plant are of medicinal value, its bark contains tannin, the lowers attract bees and thus the plant has a honey production potential; its wood and fruit can be used for numerous purposes including fuel. Of particular importance, the fruit of J. curcas contain viscous oil that can be used for soap making, in the cosmetics industry and as a diesel or kerosene substitute or extender. This latter use may be of importance when examining practical substitutes for fossil fuels to counter greenhouse gas accumulation. Also, like all trees, it fixes atmospheric carbon, stores it in wood and assists in the build up of soil carbon [4].

There are many positive claims on J. curcas, include that the crop: reclaims marginal soil, grows well under saline conditions, is drought tolerant and may have low water use (or high water use efficiency), has low nutrient requirements, is an energy crop, grows seeds with high oil contents, provides high oil yields, provides oil with high quality, requires low labor inputs, does not compete with food production, is tolerant or resistant to pests and diseases. These claims have been proved in traditional and low scale production. However, related to high oil yield production, is not backed up by scientific finding so far, especially in large scale production [5]. J. curcas is still a wild plant which exhibits a lot of variability in yield, oil content and oil quality. Given the booming interest which J. curcas receives nowadays, there is an urgent need for better data to guide investments. Preliminary results on the lifecycle energy balance and global warming potential of biodiesel from J. curcas are favorable, but it is important to note that the GHG balance is tightly linked to the type of land use which is removed and to the intensity of the cultivation [6]. Due to this unproved claims, various ministerial meetings that might have given the national mission on biofuel the seal of approval have been postponed in favour of higher-priority issues. Despite this, several states like India and China have enthusiastically hopped aboard the J. curcas express, providing free plants to small-scale farmers, encouraging private investment in J. curcas plantations and setting up biodiesel processing plants [7].

However, Jatropha biodiesel had comparable fuel properties with those of diesel and conforming to the latest standards for biodiesel (see Table 1.4) [8]. The choice of using J. curcas bio-diesel (i.e. methyl esters) or the J. curcas oil depends on the goal of the use (e.g. electricity or transport) and the available infrastructure. Studies show that transesterified J. curcas oil achieves better results than the use of pure J. curcas oil, straight or in a blend, in unadjusted diesel engines. Changing engine parameters shows considerable improvement of both the performance and the emission of diesel engines operating on neat J. curcas oil. More trials on the use of straight J. curcas oil in different diesel engine setups should be tested and investigated. Accurate measuring and reporting on emissions contributing to global warming, acidification, eutrophification, photochemical oxidant formation and stratospheric ozone depletion is very relevant. The long-term durability of the engines using bio-diesel as fuel requires further study as well [9].

Table 1.4. Fuel properties of jatropha oil, jatropha biodiesel and diesel [8]

Property Unit Jatropha oil Jatropha biodiesel Diesel Biodiesel standards
ASTM D 6751-02 DIN EN 14214
Density at 15 oC kgm-3 940 880 850 – 860-900
Viscosity at 15 oC mm2s-1 24.5 4.80 2.60 1.9-6.0 3.5-5.0
Flash point oC 225 135 68 > 130 > 120
Pour point oC 4 2 -20 – –
Water content % 1.4 0.025 0.02 < 0.03 < 0.05
Ash content % 0.8 0.012 0.01 < 0.02 < 0.02
Carbon residue % 1.0 0.20 0.17 – < 0.30
Acid value mgKOHg-1 28.0 0.40 – < 0.80 < 0.50
Calorific value MJ kg-1 38.65 39.23 42 – –

References:

  1. Nature Editorial, Kill king corn, Nature, 2007, 449, 637.
  2. G. M. Gübitz, M. Mittelbach, and M. Trabi, Exploitation of tropical oil seed plant Jatropha curca L., Bioresources Technology, 1999, 67, 73-82.
  3. H. P. S. Makkar, A. O. Aderibigbe, and K. Becker, Comparative evaluation of non-toxic and toxic varieties of Jatropha curcas for chemical composition, digestibility, protein degradability and toxic factors, Food Chemistry, 1998, 62 (2), 207-215.
  4. K. Openshaw, A review of Jatropha curcas: an oil plant of unfulfilled promise, Biomass and Bioenergy, 2000, 19, 1-15.
  5. R. E. E. Jongschaap, W. J. Corre, P. S. Bindraban and W. A. Bradenburg, Claims and facts on Jatropha curcas L.: Global Jatropha curcas evaluation, breeding and propagation programme, Plant Research International B.V., Wageningen, 2007, 44 pp.
  6. W. M. J. Achten, E. Mathijs, L. Verchot, V. P. Singh, R. Aerts, and B. Muys, Jatropha biodisesel fueling sustainability?, Biofuels, Bioprod. Bioref., 2007, 1, 283-291.
  7. D. Fairless, The little shrub that could – maybe, Nature, 2007, 449, 652-655.
  8. A. K. Tiwari, A. Kumar, and H. Raheman, Biodiesel production from jatropha oil (Jatropha curcas) with high free fatty acids: An optimized process, Biomass and Bioenergy, 2007, 31, 569-575.
Energy ,

Vegetable oils as biofuels

March 2, 2010 1 comment

The term biofuels is the fuel derived from biomass, while biomass represents an abundant carbon-neutral renewable resource for the production of bioenergy and biomaterials. Technologies used related to genetics, biotechnology, process chemistry, and engineering in converting renewable biomass to valuables fuels and products, called the biorefinery [1]. These technologies include fermentation, photosynthesis and biological water-gas shift reaction (BWGS) of hydrogen productions, and also hydrolysis and fermentation of bio-ethanol production [2]. Other technologies are microbial photolysis, hydrogenation, anaerobic digestion, gasification, pyrolysis, catalytic cracking, saccharification, transesterification [3], genetically engineered bacteria or yeast, and MixAlco process [4]. The sources of biomass or lignocellulosic can be derived directly from energy crops, or recycling waste edible oil. Some countries with limited natural resources like Taiwan, biodiesel production by re-use waste edible oils can reduce air emissions and increase domestic supply energy [5].

By using biofuels, theoretically because of its CO2-neutral, therefore may help to control the carbon content of the atmosphere [6], though several studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions similar to those of gasoline [7]. However, biofuels still have many advantages i.e.: availability, renewability, higher combustion efficiency, lower emissions, and its biodegradability [8].

Even tough biofuels have bright potency in the future, the serious problem should be considered, these are how to balances natural vegetation and cultivation, arable and marginal land use, mechanized agriculture and employment opportunities, and also food or energy crops priority [9]. Currently, more than 95% of the world biodiesel is produced from edible oil which is easily available on large scale from the agricultural industry. This is due to the increasing of bioenergy crops, especially for corn harvested. In the U.S. case, corn grain yields have risen dramatically and steadily over the past 35 years (1965-2000) at an average annual change of 1.7 bushels per acre even while fertilizer inputs have declined [10]. In the term of crop residue, which is defined as the non-edible plants parts that are left in the field after harvest, corn also takes a first place (see Table 1.1). This condition also similar in the world estimation amount as well as the U.S. amounts [11]. While, consider to direct use as biofuel, the phospatides content of corn oil is the lowest one among seven vegetable oils (see Table 1.2) [12]. These data make edible oils still favorite source of biofuel over the world.

Table 1.1.  Estimate amount of crop residue produced by different crops in US [11]

Crop Residue amount on dry weight basis

(Mg/ha/crop)
Barley (Hordeum vulgare) 4.3
Corn (Zea mays) 10.1
Cotton (Gossypium hirsutum) 6.7
Oats (Avena sativa) 5.6
Peanuts (Arachishypogea) 5.6
Rice (Oryza sativa) 6.7
Sorghum (Sorghum bicolor) 8.4
Tobacco (Nicotiana tabacum) 4.0
Tomatoes (Lycopersicon esculentum) 5.0
Sugarbeet (Beta vulgaris) 5.6
Wheat (Triticum aestivum) 5.0

Table 1.2. Acid value, phospatide content and peroxide value of seven vegetable oils [12]

Vegetable oil Acid value a) Phospatide/gum b) Peroxide value c)
Corn 0.11 7.00 18.4
Cottonseed 0.07 8.00 64.8
Crambe 0.36 12.00 26.5
Peanut 0.20 9.00 82.7
Rapeseed 1.14 18.00 30.2
Soybean 0.20 32.00 44.5
Sunflower 0.15 15.00 10.7

a) Acid values are milligrams of KOH necessary to neutralize the FFA in 1 g of oil sample.

b) Phosphatide (gum) content varies in direct proportion to phosphorus value.

c) Peroxide values are milliquivalents of peroxide per 1000 g of oil sample, which oxidize potassium iodide under conditions of the test.

Fuel properties of vegetable oils were characterized by determining its viscosity, density, cetane number, cloud and pour points, distillation range, flash point, ash content, sulfur content, carbon residue, acid value, copper corrosion and HHV (higher heating value). The viscosity, density, flash point, and higher heating value (HHV) measurements of twenty two vegetable oils and their methyl esters are given in Table 1.3 [13].

However, continuous and large-scale production of biodiesel from edible oil without proper planning may cause negative impact to the world, such as depletion of food supply leading to economic imbalance. A possible solution to overcome this problem is to use non-edible oil or waste edible oil (WEO) [14].

Table 1.3. Viscosity, density, flash point and higher heating value (HVV) measurements of twenty two vegetable oils and fourteen oil methyl esthers [13]

Viscosity (cSt) Density (g/L) Flash point (K) HHV(MJ/kg)
Vegetable oil
Ailanthus 30.2 916 513 39.44
Bay laurel 23.2 921 499 39.30
Beech 34.6 915 515 39.59
Beechnut 38.0 912 533 39.82
Corn 35.4 914 532 39.66
Cottonseed 33.5 915 524 40.38
Crambe 53.0 902 557 39.83
Hazelnut 24.0 920 503 39.33
Linseed 27.2 921 520 39.50
Mustard oil 33.8 913 518 39.57
Olive 29.8 918 504 39.50
Palm 24.1 923 501 39.74
Peanut 39.6 908 543 39.85
Poppy seed 42.4 907 538 39.73
Rapeseed 37.3 912 531 39.52
Safflower seed 31.3 914 531 39.79
H.O. Safflower 41.2 906 548 39.51
Sesame 35.5 913 533 39.63
Soybean 32.6 914 528 39.44
Spruce 35.6 914 513 39.57
Sunflower seed 33.9 916 535 39.59
Walnut 36.8 912 524 No data
Methyl ester
Cottonseed oil 3.75 871 455 41.18
Corn oil 3.62 873 427 41.14
Crambe oil 5.12 848 463 41.98
Hazelnut oil 3.59 875 427 41.12
Linseed oil 2.83 885 415 40.84
Mustard oil 4.10 866 442 41.30
Olive oil 4.18 860 447 41.35
Palm oil 3.94 867 434 41.24
Rapeseed oil 4.60 857 453 41.55
Safflower oil 4.03 866 440 41.26
Sesame oil 3.04 880 418 40.90
Soybean oil 4.08 865 441 41.28
Sunflower oil 4.16 863 439 41.33
Walnut oil 4.11 864 443 41.32

References:

  1. A. J. Ragauskas, C. K. Williams, B. H. Davison, G. Britovsek, J. Cairney, C. A. Eckert, W. J. Frederick Jr., J. P. Hallet, D. J. Leak, C. L. Liotta, J. R. Mielenz, R. Murphy, R. Templer, and T. Tschaplinski, The path forward for biofuels and biomaterials, Science, 2006, 311, 484-489.
  2. R. C. Saxena, D. K. Adhikari, and H. B. Goval, Biomass-based energy fuel through biochemical routes: A review, Renewable and Sustainable Energy Reviews, 2009, 13, 167-178.
  3. R. Luque, L. Herrero-Davila, J. M. Campelo, J. H. Clark, J. M. Hidalgo, D. Luna, J. M. Marinas and A. A. Romero, Biofuels: a technological perspective, Energy and Enviromental Science, 2008, 1, 542-564.
  4. B. C. Saha and J. Woodward (eds.), Fuels and Chemicals from Biomass, ACS Symposium Series, 666, American Chemical Society, Washington, DC., 1997, 356 pp.
  5. Y. H. Huang and J. H. Wu, Analysis of biodiesel promotion in Taiwan, Renewable and Sustainable Energy Reviews, 2008, 12, 1176–1186.
  6. G. Schaub and A. Vetter, Biofuels for automobiles – an overview, Chem. Eng. Technol., 2008, 31, No. 5, 721–729
  7. A. E. Farrell, R. J. Plevin, B. T. Turner, A. D. Jones, M. O’Hare, and D. M. Kammen, Ethanol can contribute to energy and environmental goals, Science, 2006, 311, 506-508.
  8. A. Demirbas, Importance of biodiesel as transportation fuel, Energy Policy, 2007, 35, 4661–4670.
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  10. R. D. Perlack et.al., Biomass as feedstock for a bioenergy and bioproduct industry: The technical feasibility of a billion-ton annual supply, U.S. Department of Energy and U.S. Department of Agriculture, 2005; available at http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf.
  11. R. Lai, World crop residue production and implications of its use as biofuel, Environment International, 2005, 31, 575-584.
  12. C. E. Goering, A. W. Schwab, M. J. Daugherty, E. H. Pryde, and A. J. Heakin, Fuel properties of eleven oils, Trans. ASAE, 1982, 25, 1472-1483.
  13. A. Demirbas, Relationship derived from physical properties of vegetable oil and biodiesel fuels, Fuel, 2008, 87, 1743-1748
Energy , ,

Renewable energy

March 2, 2010 No comments

The world community today faces many problems, from economical instability to biodiversity extinction, from governance crisis to natural disasters. Addressing these problems calls out for a huge amount of research to be conducted to rescue human life. Scientists have to work by identifying the problems, developing future scenarios and evaluating management options.

Some researchers and policy makers prioritized several world’s biggest problems especially which ones relatively non-economic and political related problems were the unsafe water and sanitation, rapid global warming, and the limitation of known petroleum reserves. However, air pollution and climate change are major threats to living species health and also political stability. Energy insecurity and increasing prices of conventional energy sources are also greatest tendency to the fragility of politic and economic.

Air pollution and climate change problems are caused primarily by exhaust from solid, liquid, and gas combustion during energy production and use. Then, such problems can be addressed only with large-scale changes to energy sector, include how to secure undisrupted energy demand from world population, especially with the fossil-fuels production which close to peak and that peak will be followed by rapid decline. The proposed fuel and electric power sources were solar photovoltaic (PV), concentrated solar power (CSP), wind turbines, geothermal power plants, hydroelectric power plants, wave devices, tidal turbines, nuclear power plants, coal power plants fitted with carbon capture and storage (CCS) technology, and ethanol/gasoline and biodiesel as biofuels [1]. Other options like algae, butanol, hydrogen combustion, and solar hot water heaters.

The prospects for biofuels have improved tremendously over the last 2 years driven foremost by concerns for energy security and climate change and the high oil prices in combination with decreasing production costs. Global biofuel production has increased by 70% over the last 2 years reaching 1.1 mmbls/d in 2007, accounting for 1.3% of global liquids supply. The USA, Brazil and Europe account for the bulk of global biofuel production. While ethanol is the dominating biofuel product in Brazil and the USA, biodiesel is the main product within Europe accounting for more than 80% of total biofuel production [2].

References:

  1. M. Z. Jacobson, Review of solutions to global warming, air pollution, and energy security, Energy Environ. Sci., 2009, 2, 148-173.
  2. J. Kjarstad and F. Johnsson, Resources and future supply of oil, Energy Policy, 2009, 37, 441–464.
Energy

Huanying Guanglin – 欢迎光临

February 23, 2010 No comments

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Huanying Guanglin. Welkom.

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吳穎書 (Yusuf Wibisono, S.TP., M.Sc.)

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