Jatropha curcus a source of Biofuel in developing countries<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
General introduction
Jatropha is bush that grows in the warm regions of the world as it is sensitive to colder climates. Once it’s planted it grows and produces nuts that contain oil within a few years, and produces these annually for up to 50 years. Climate requirement for the plant is as altitude: 0-500 meters above sea level. mild-annual temperature: 20-28 °C.annual rainfall: 300-1000 mm., or more.
Jatropha has been grown in developing countries for many years it’s been used locally for production of oil that was used in local village based industries for soap production. Since the plants are toxic they have also been used to plant hedges and to keep animals out of areas of land.
Botany
Jatropha plant is a small tree with smooth grey bark, which exudes a whitish coloured, watery, latex when cut. It grows between 3 to 5 meters in height, and up to 8 to 10 meters under favourable conditions, shrubs or trees with spreading branches and stubby twigs, with a milky or yellowish rufescent exudate.
Leaves –Leaves are deciduous, alternate but apically crowded, ovate, acute to acuminate, basally cordate, 3 to 5-lobed in outline, 6–40 cm long, 6–35 cm broad, the petioles 2.5–7.5 cm long.
Flowers – Flowers are many in greenish cymes, yellowish, bell-shaped; sepals 5, broadly deltoid. Male flowers many with 10 stamens, 5 united at the base only, 5 united into a column. Female flowers borne singly, with elliptic 3-celled, triovulate ovary with 3 spreading bifurcate stigmata.
Fruits -Fruits are produced in winter when the shrub is leafless, or it may produce several crops during the year if soil moisture is good and temperatures are sufficiently high. Each inflorescence yields a bunch of approximately 10 or more ovoid fruits. - 2.5–4 cm long, finally drying and splitting into 3 valves, all or two of which commonly have an oblong black seed, the seeds mature and the fleshy exocarp dries
Description
Shrub or tree to 6 m, with spreading branches and stubby twigs, with a milky or yellowish rufescent exudate. Flowers several to many in greenish cymes, yellowish, bell-shaped; sepals 5, broadly deltoid. Male flowers many with 10 stamens, 5 united at the base only, 5 united into a column. Female flowers borne singly, with elliptic 3-celled, triovulate ovary with 3 spreading bifurcate stigmata. Capsules, 2.5–4 cm long, finally drying and splitting into 3 valves, all or two of which commonly have an oblong black seed, these ca 2 x 1 cm (Morton, 1977; Little et al., 1974).
Uses of Jatropha
Jatropha is considered as a poor quality fuelwood since the soft wood burns too rapidly. In <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Africa, Jatropha is widely planted as a “living fence” and hedgerows to protect food crops from damage by livestock and as a windbreak to prevent soil erosion moisture depletion. In Madagascar, Jatropha is used as a support plant for Vanilla. The bark is reported to yield tannin in commercially useable quantities. In a startling 1982 study, several oil-energy species with the potential to grow in Malagasy (Madagascar) were compared, and Oil palm was considered energetically more promising than Jatropha; nevertheless, around 10,000 ha have been planted to Jatropha (although the citation did not specify whether the plantings were J. curcas or J. mahafalensis, ed.). Other studies conclude that using the oil to make soap is more profitable than using it as biodiesel; however, this was before the recent rise in fuel costs
In India, pounded leaves are applied near horses' eyes to repel flies. Nuts can be strung on grass and burned like candlenuts. The oil has been used for illumination, making candles and soap, adulterating olive oil, and making Turkey red oil. Mexicans grow the shrub as a host for the lac insect that secretes resin used as a dye and to make shellac. Ashes of the burned root are sometimes used as a salt substitute. Jatropha has been found to have strong molluscicidal activity and the latex to be strongly inhibitory to watermelon mosaic virus. It is also listed as a homicide, piscicide and raticide.
Uses
According to Ochse (1980), "the young leaves may be safely eaten, steamed or stewed." They are favored for cooking with goat meat, said to counteract the peculiar smell. Though purgative, the nuts are sometimes roasted and dangerously eaten. In India, pounded leaves are applied near horses' eyes to repel flies. The oil has been used for illumination, soap, candles, adulteration of olive oil, and making Turkey red oil. Nuts can be strung on grass and burned like candlenuts (Watt and Breyer-Brandwijk, 1962). Mexicans grow the shrub as a host for the lac insect. Ashes of the burned root are used as a salt substitute (Morton, 1981). Agaceta et al. (1981) conclude that it has strong molluscicidal activity. Duke and Wain (1981) list it for homicide, piscicide, and raticide as well. The latex was strongly inhibitory to watermelon mosaic virus (Tewari and Shukla, 1982). Bark used as a fish poison (Watt and Breyer-Brandwijk, 1962). In South Sudan, the seed as well as the fruit is used as a contraceptive (List and Horhammer, 1969–1979). Sap stains linen and can be used for marking (Mitchell and Rook, 1979). Little, Woodbury, and Wadsworth (1974) list the species as a honey plant.
Medicinals
Although toxic, Jatropha is known as the physic or purging nut for its use as purgative/laxative, and is widely known as a source of medicinals for treatment of a variety of ailments. A range of healing properties have been ascribed to leaf preparations for both topical application and ingestion. Duke provides a most extensive list of its various uses in folk medicine.
Folk Medicine
According to Hartwell, the extracts are used in folk remedies for cancer. Reported to be abortifacient, anodyne, antiseptic, cicatrizant, depurative, diuretic, emetic, hemostat, lactagogue, narcotic, purgative, rubefacient, styptic, vermifuge, and vulnerary, physic nut is a folk remedy for alopecia, anasorca, ascites, burns, carbuncles, convulsions, cough, dermatitis, diarrhea, dropsy, dysentery, dyspepsia, eczema, erysipelas, fever, gonorrhea, hernia, incontinence, inflammation, jaundice, neuralgia, paralysis, parturition, pleurisy, pneumonia, rash, rheumatism, scabies, sciatica, sores, stomachache, syphilis, tetanus, thrush, tumors, ulcers, uterosis, whitlows, yaws, and yellow fever (Duke and Wain, 1981; List and Horhammer, 1969–1979). Latex applied topically to bee and wasp stings (Watt and Breyer-Brandwijk, 1962). Mauritians massage ascitic limbs with the oil. Cameroon natives apply the leaf decoction in arthritis (Watt and Breyer-Brandwijk, 1962). Colombians drink the leaf decoction for venereal disease (Morton, 1981). Bahamans drink the decoction for heartburn. Costa Ricans poultice leaves onto erysipelas and splenosis. Guatemalans place heated leaves on the breast as a lactagogue. Cubans apply the latex to toothache. Colombians and Costa Ricans apply the latex to burns, hemorrhoids, ringworm, and ulcers. Barbadians use the leaf tea for marasmus, Panamanians for jaundice. Venezuelans take the root decoction for dysentery (Morton, 1981). Seeds are used also for dropsy, gout, paralysis, and skin ailments (Watt and Breyer-Brandwijk, 1962). Leaves are regarded as antiparasitic, applied to scabies; rubefacient for paralysis, rheumatism; also applied to hard tumors (Hartwell, 1967–1971). Latex used to dress sores and ulcers and inflamed tongues (Perry, 1980). Seed is viewed as aperient; the seed oil emetic, laxative, purgative, for skin ailments. Root is used in decoction as a mouthwash for bleeding gums and toothache. Otherwise used for eczema, ringworm, and scabies (Perry, 1980; Duke and Ayensu, 1984). Four antitumor compounds, including jatropham and jatrophone, are reported from other species of Jatropha (Duke and Ayensu, 1984). Homeopathically used for cold sweats, colic, collapse, cramps, cyanosis, diarrhea, leg cramps
Human consumption
Jatropha can be toxic when consumed; however, a non-toxic variety of Jatropha is reported to exist in Mexico and Central America, said not to contain toxic Phorbol esters. This variety is used for human consumption after roasting the seeds/nuts, and "the young leaves may be safely eaten, steamed or stewed." They are favored for cooking with goat meat, said to counteract the peculiar smell. As such, it is suggested by some that “This non-toxic variety of Jatropha could be a potential source of oil for human consumption, and the seed cake can be a good protein source for humans as well as for livestock.” This non-toxic variety has not been studied as well as the toxic varieties; therefore, its properties and yields are relative unknown and “claims” unproven. The IPGRI study reports that the seeds are edible, once the embryo has been removed (no indication of which variety, ed.).
Jatropha Oil
It is unclear how much genetics play in the amount of oil contained in Jatropha seed and kernels; nevertheless, estimates of the oil content in seeds range from 35-40% oil and the kernels 55-60%. However, the amount of actual oil produced from seeds and kernels is contingent upon the method of extraction, with hand presses extruding only about 20% and more sophisticated a much higher quantity. The by-product of oil extraction from the seeds and kernels is called seed cake, and when oil is extracted as a cottage industry the resulting cake is said to still contain approximately 11% oil. The more sophisticated and efficient method of extraction produces seed-cake with much lower oil content.
The clear oil expressed from the seed has been used for illumination and lubricating, and more recently has been suggested for energetic purposes as a substitute for diesel. One source reports that one ton of nuts yield an estimated 70 kg refined petroleum, 40 kg "gasoil leger" (light fuel oil), 40 kg regular fuel oil, 34 kg dry tar/pitch/rosin, 270 kg coke-like char, and 200 kg ammoniacal water, natural gas, creosote, etc.
Oil for lighting and cooking
Jatropha nuts can be strung on grass and burned like candlenuts, and the oil to make candles. Although many researchers have described Jatropha as a potential domestic fuel for cooking and lighting, with properties similar to kerosene, it cannot be used directly in conventional kerosene stoves or lamps. High ignition temperatures and viscosity (75.7 10-6 m2/s) as compared to kerosene (50-55 C, and 2.2 10-6m2/s respectively) mean that Jatropha oil will not burn as well, and would clog up all the tubes and nozzles in a conventional stove or lamp. Approaches to circumventing these problems are being tried. A low intensity lamp with a wick has been developed. The oil lamp requires a very short wick so that the flame is very close to the oil surface.
Biodiesel
The market that excites the most interest is that for biodiesel. However, there are several points of view that differ considerably regarding Jatropha’s suitability as a substitute for petroleum products. Right now these views yield less in actual sales than in prospects. How quickly these prospects will develop depends on the observer’s point of view. Jatropha oil has long been seen as a possible substitute for fuel oil for diesel engines. This is the product where interest is highest and most research is being conducted.
Unrefined Jatropha oil can only be used in certain types of diesel engines, such as Lister-type engines; but even then they require modifications, and are high-maintenance. The Lister type engine is commonly used in developing countries to run small-scale flourmills or electric generators. These engines also have to be located in warm climates because the viscosity of Jatropha oil is too high at low temperatures. However, any diesel engine, with no modification other than the replacing of natural rubber with synthetic rubber hoses (which late model engines do not have anyway), can run on Jatropha fuel once the oil has gone through a process called trans-esterification.
According to the IPGRI publication, the trans-esterification is process is normally carried out in centralized plants since the small-scale economy of trans-esterification has not been determined. During the process, methanol, a highly flammable and toxic chemical, has to be used, and this requires explosion-proof equipment that might not be available in developing countries. The WSU study contradicts the IPGR statement by claiming that the process is simple to carry out by just mixing the oil with methanol and caustic soda and leaving it to stand; nevertheless, the chemicals are toxic and highly flammable, and the processing dangerous. Regardless, this could be dangerous.Glycerin settles to the bottom of the tank, leaving the methyl ester, or biodiesel, at the top. This warrants further investigation in order to determine which statement is true. Perhaps both statements are true, and the former process is for more commercial-scale operations, and the latter is an “appropriate technology” developed for small-scale, cottage-industry producers.
Biodiesel is reported to be environmentally superior to petroleum diesel, for Jatropha biodiesel emits about two-thirds less in unburned hydrocarbons and almost half as much carbon monoxide and particulate matter as conventional diesel. It contains no sulfur and so emits none. From the point of view of global warming, it is neutral in its net addition to greenhouse gasses because the carbon dioxide released in combustion was sequestered when growing the crop (this claim is questionable, since CO2 released would soon equate the CO2 sequestered by the plants after a relative short time, ed.). The WSU study optimistically concludes that while many vegetable oils are used to manufacture biodiesel, a given amount of land will produce much more oil from Jatropha than from the common alternatives (soybeans, cotton seed, rapeseed, sunflower, groundnuts).
The glycerin by-product of the trans-esterification process can be used to make a high quality soap, or it can be refined and sold at a range of prices, depending on its purity, to be used in an immense range of products, including cosmetics, toothpaste, embalming fluids, pipe joint cement, cough medicine, and tobacco (as a moistening agent).
Comments