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Difference between revisions of "Copra Extraction Meal"

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| humidity and moisture              = <ul><li>Relative humidity: 70% </li><li>Water content: 5 - 10%</li><li>Maximum equilibrium moisture content: 70%</li></ul>  
 
| humidity and moisture              = <ul><li>Relative humidity: 70% </li><li>Water content: 5 - 10%</li><li>Maximum equilibrium moisture content: 70%</li></ul>  
 
| oil content                        = 0.1 - 1.5%  
 
| oil content                        = 0.1 - 1.5%  
−
| ventilation                        = Copra extraction meal requires particular temperature, humidity/moisture and ventilation conditions.<br>Recommended ventilation conditions: surface ventilation.<br>(See text for more details).
+
| ventilation                        = Copra extraction meal requires particular temperature, humidity/moisture and ventilation conditions.<br>Recommended ventilation conditions: surface ventilation.<br>
−
| risk factors                        = Copra extraction meal readily becomes rancid.<br>Copra extraction meal is liable to the risk of self-heating/spontaneous combustion.<br>Copra extraction meal is assigned to class 4.2, pursuant to the IMDG Code. All types and varieties of pellets, expellers and extracts fall within the class "Seed Cake" under UN numbers 2217 and 1386.
+
| risk factors                        = Copra extraction meal readily becomes rancid.<br>Copra extraction meal is liable to the risk of self-heating/spontaneous combustion.
 
}}
 
}}
  
 
==Description==
 
==Description==
−
[[Coconut]] extraction meal comprises residues arising from oil extraction from [[copra]] (coconut flesh) performed using an extraction solvent.
+
[[Coconut Oil]] is obtained by extracting the oil contained in [[copra]]. The residue is generally called copra cake, sometimes it is called copra meal. Coconut oil is used for food and for industrial purposes. Edible oil, by international standards should have less than 0.1% free fatty acid content. The oil obtained from good quality copra, with a free fatty acid content of < 0.1%, is used as cooking oil without any further processing. Even if the free fatty acid content is 3-5%, the international standard of < 0.1% can be obtained by refining and deodorizing. Edible oils are either used as cooking oil (frying oil) or processed further into filled milk, table margarine and baker's margarine.<br><br>
 +
In industry, coconut oil is used for manufacturing toilet and laundry soap. In its original or modified form, it is used as a vehicle in the paint and varnish industry. Coconut oil is also processed into methyl esters, [[Fatty Acids]] and fatty alcohols. These intermediate products are raw materials for manufacturing detergents, surfactants, emulsifiers, plasticizers and various other organic products which are bio-degradable. [[Copra]] cake is used in blending animal feed.<br><br>
 +
Expellers are the residue from processing by the continuous screw process, with an oil content of between 1,5-7%, but sometimes more if old machinery has been used.<br>
 +
Extractions are the residue after solvent extraction of the oil, the remaining oil content is >1,5%. Usally in the form of regular [[grain]]-sized pellets.<br><br>
 +
'''Extraction Technology, Dry Processing:'''<br>
 +
Oil extraction from copra is carried out by two methods: mechanically by pressing; or by use of solvents. Mechanical and solvent extraction uses standard technology that has been developed in the vegetable oil industry. For [[Oil Seeds]] such as copra which have a high oil content, mechanical extraction is efficient and economical. For oil [[seeds]] with low oil content or for further oil extraction from copra cake, the solvent extraction method is more suitable. The residual material from solvent extraction is called copra meal. Oil extraction involves five basic steps: copra storage; preparation of copra; oil extraction - full press, prepress - solvent, and full solvent methods; processing of extracted oil; processing of cake or meal and storage of products.<br><br>
 +
'''Full press method:'''<br>
 +
In the full press method of oil extraction, maximum pressure is applied to the material and sufficient time is allowed for the oil to escape. The temperature of the material should not be allowed to rise to a level where the oil darkens due to overheating. The pressure is applied to the material between the screws and the cage of slitted steel bars. Pressing may be done in a single or in double stages. By adjusting the clearance in the choking device, the thickness of the cake can be controlled. When the clearance is reduced to decrease the thickness of the cake, the pressure applied is increased. To prevent overheating the oil, the shaft is usually hollow for water cooling, and the oil is sprinkled over the cage bars.<br><br>
 +
'''Prepress-solvent method:'''<br>
 +
In the prepress-solvent process, the oil is partially extracted by preliminary low pressure mechanical extraction, and then subjected to solvent extraction to remove most of the residual oil. The oil content of the initial copra material is around 70%; after the mechanical prepress extraction, the residual oil content in the prepressed cake is 16 - 20% for optimum operation. After full press extraction, the oil content in the residual copra cake is 6 - 10%, depending upon efficiency. The equipment used for prepressing is similar to expellers used for full pressing, but adjusted for less pressure and therefore it has a higher throughput.<br><br>
 +
'''Full solvent method:'''<br>
 +
In solvent extraction, oil in the material is leached with a solvent (where the oil dissolves in the solvent) whereas the insoluble meal is retained unaffected. The extent of extraction depends upon the kind of solvent, the temperature of solvent, the ratio of solvent to meal, the number of extraction stages, the shape of particles, the porosity of the material, and the [[contact]] duration. The most common solvent used is {{hexane}} because of its price, low toxicity, suitable boiling point for recovery and handling, and its availability. Solubility of oil in hexane increases with temperature.<br><br>
 +
The resulting streams from solvent extraction are: the micella or oil, solvent solution, and the extracted meal which comprises the meal, some solvent and a little residual oil. The solvent in the meal is removed by heating to boil off the volatile solvent, and the solvent is recovered by condensation. The solvent from the micella is removed and recovered by evaporation and condensation. Traces of solvent left in the meal and the oil are removed by steam-stripping under reduced pressure.<br><br>
 +
The equipment for solvent extraction consists of two general types; the roto-cell type with cells revolving around a vertical axis, and the basket type with baskets travelling horizontally while the solvent is sprayed over the material in counter-current flow. In the full solvent process, the prepared copra is first subjected to a first extraction (percolation), using the weak micella from the second extractor as starting solvent, and producing the strong micella for oil recovery. The extracted meal is then flaked and subjected to a second extraction (immersion) which uses fresh solvent as starting solvent and produces the weak micella solvent for the first extractor. The solvent with the extracted oil is removed in a Desolventizer-Toaster (DT) which is either of the multi-decked vertical design with steam heated pans and paddle scrapers, or the horizontal barrel type with rotating conveying paddles attached to a horizontal shaft, and steam jacketed walls. These are equipped with condensers for solvent recovery and scrubbers to remove dust entrained in the vapours. In some designs, the heat with the vapours leaving the DT is used to pre-concentrate the micella prior to evaporation of the micella.<br><br>
 +
The solvent with the micella is recovered, first by an evaporator, usually of the falling film type, where hexane is distilled off by indirect steam heating, and subsequently by a stripping column where traces of hexane in the oil are stripped by steam under vacuum. The water-hexane vapours from the stripper are condensed and collected in a water-hexane separator where hexane is separated by gravity from the water. It is decanted and reused in the extraction. Vent vapours of hexane from the extractors and condensers are recovered in a vent recovery system where hexane is absorbed by mineral oil. Hexane is recovered from the mineral oil by stripping, and recycled to the extractor.<br><br>
 +
'''Processing extracted oil:'''<br>
 +
Processing the extracted oil is the next basic step in the oil extraction technology. Oil from the expellers contain substantial quantities of solids (foots) that should be removed before the oil is pumped into the storage tanks. The oil is cleaned first by settling and screening and subsequently by filtration. The screening equipment is a rectangular steel tank equipped with a continuous drag chain conveyor with scraper blades, which scoop the settled solids and lift them over a fine screen for drainage at one end of the screening tank, after which they are conveyed back to the expellers to be mixed with the copra. The filtering equipment generally consists of a plate and frame filter press with canvass filtering media. Some factories use leaf filters with perforated steel filtering leaves. The foots or filter cake from the filters are recycled to the expellers for oil extraction. The oil from solvent extraction is free of solids. It leaves the stripping column at 120°C and is cooled and pumped into the storage tanks through an oil meter.<br><br>
 +
'''Processing cake or meal:'''<br>
 +
Copra cake leaving the expellers has a temperature of about 110 °C and is cooled in a cake cooler. The cake cascades down the cooler baffles and is cooled by a cross-flow of cooled air from blowers. After cooling, it is ground to fine particles by hammer mills or disc mills. The ground cake is bagged for local use or pelletized for export. Pelletizing requires additional equipment which small [[plants]] cannot afford. However, cake or meal for export has to be pelletized for safer and easier handling and conveying. Prior to pelletizing, the cake has to be moistened to about 12% moisture and then fed to the pellet mill. Moistening in this manner improves pelleting property, and is required for export. The oil content of copra cake should be around 6 to 10% and moisture not higher than 12%. For [[Copra Expeller]], the oil content is approx. 1,5-7% and for copra meal  0.5 - 1,5% depending on the efficiency of solvent extraction. Due to absorption, the moisture level rises during storage.<br><br>
 +
'''Storage of products:'''<br>
 +
The unpelletized copra cake should be bagged in woven sacks and stacked about 10 high on wooden pallets. It is hazardous to store unpelletized cake in bulk for long periods. The piles of unbagged meal should be kept small and turned over as frequently as necessary to prevent spontaneous combustion.<br><br>
 +
The (hot) finished expellers leave the production plant with a variable moisture content. After pressing, the expellers are cooled and, since they are in large pieces, they are ground and adjusted to a water content suitable for storage and transport. The ground products are then held in intermediate storage in silo cells or sent for transport.<br><br>
  
−
The starting materials for this solvent extraction process are oil [[seeds]] with a low oil content or expeller pulp produced by previous cold or hot pressing (Manufacture of vegetable pressing residues). The oil is extracted from the rough-ground product by chemical fat solvents (n-hexane), leaving a residual oil content of only 0.5 - 1.5%. These residues are then known as extraction meal.
+
==Applications==
 +
Copra cake/expeller/meal is used as an ingredient in blending animal feed, due to the presence of oil, protein and carbohydrates. Copra cake from poor quality copra has a limited market due to its degraded condition and the presence of aflatoxin.<br><br>
  
−
After extraction of the fat, the solvent is removed from solvent-damp extraction residues in a toaster (desolventizer) using steam.
+
==Shipment/storage==
 +
Upon shipment, the copra produce should be accompanied by certificates stating the moisture, residual oil content and the maturing time of the product. It should also be stated that the product really is expeller and not extraction meal (extracting agent/solvent content). Oil contents of < 1.5% are indicative of extraction meal.<br><br>
 +
Overheating during the production process, or subjecting the product to pro longed storage, may be manifested by brown or reddish to black discoloration. Expeller/Extraction meal is mainly transported as [[Bulk Cargo]]. <br><br>
 +
Favorable travel temperature: 5 - 25°C. <br>
 +
At elevated external temperatures, the product temperature must be no more than 10% higher than the external temperature. <br>
 +
In tropical ports, temperatures of 25 - 55°C may occur in the products to be loaded.<br><br>
 +
If the cargo temperature during the voyage rises to >55°C and any further increase is observed, adequate measures must be taken, e.g. tight closing of all hatch openings and injection of CO<sub>2</sub> or inert gas may have to be considered. <br>
 +
Stow away from heat sources (i.e. engine room bulkheads, heated fuel tanks, etc.).<br><br>
  
−
The primary advantage of n-hexane as an extraction solvent over other solvents is that it is readily removable from the extracted products; residues should be at most 0.05 - 0.1%. It has the disadvantage, however, of being readily combustible. Toasting of the product at temperatures of 60°C upwards has favorable side-effects:
+
Note:<br>
 +
See also advice on overseas shipment of '''[[Seedcake]]''' and '''[[Expellers and Extractions]]'''<br><br>
  
−
it leads to the deactivation of microorganisms and enzymes which may have deleterious effects on feedstuffs during storage and transport
+
==Risk factors==
−
toasting converts the vegetable protein into a readily digestible form.
+
- Humidity/Moisture<br>
 +
- Self-heating / Spontaneous combustion<br>
 +
- Contamination<br>
 +
- Toxicity / Hazards to health<br>
 +
- Shrinkage/Shortage<br>
 +
- Insect infestation / Diseases<br>
  
−
Toasted extraction meal leaves the production plant while still hot and with a variable moisture content. After toasting, the extraction meal is cooled and, since it is in large pieces, it is ground and adjusted to a water content suitable for storage and transport.
+
Note: Reference is made to the relevant IMO regulations on hazardous cargo.<br>
−
 
 
−
It is either held in intermediate storage in silo cells or sent for transport. It is transported as bulk cargo, being seldom handled as bagged goods these days.
 
−
 
 
−
Oil content: 0.1 - 1.5%
 
−
 
 
−
<b>Intended use</b><br>
 
−
Due to its high protein content, copra extraction meal constitutes a valuable concentrated feed additive for mixed livestock feed. Copra extraction meal is a particular favorite of dairy cattle, increasing the fat content of their milk and giving it a sweetish, nutty flavor and yellow color.
 
−
 
 
−
==Storage/shipment==
 
−
Product intended for shipping must be adequately matured. The time required for maturing is determined by the oil content. On the other hand, however, product from the previous year's harvest must not be accepted for shipping.
 
−
 
 
−
The consignor must provide certificates relating to the moisture and residual oil content and the maturing time of the product. Confirmation or certification should also be obtained that the product is extraction meal.
 
−
 
 
−
Copra extraction meal consists of light gray to yellowish flakes of varying sizes. Upon acceptance of a consignment, brown or reddish to black discoloration of the goods must be looked for, since this indicates overheating during toasting or excessively long storage.
 
−
 
 
−
Extraction meal is mainly transported as bulk cargo. Only exceptionally is the product transported as bagged cargo (in very small quantities).
 
−
 
 
−
Bulk containers subject to compliance with lower and upper limits for water and oil content and the maturing time of the product and water content of the container floor (see RF Self-heating, possible fire hazard due to solvent residues).
 
−
 
 
−
Do not unload very hot product with hydraulically operated grabs as the hydraulic lines are not capable of withstanding such elevated temperatures. Use only cable-operated grabs for spontaneously heated product.
 
−
 
 
−
In order to ensure better utilization of transport volume, copra extraction meal should be compressed. Storage in silo cells is risk-free.
 
−
 
 
−
Stow cool, dry. Mechanical [[ventilation]] of the stowage spaces must be possible. Do not stow over heated double bottom tanks, close to the engine room bulkhead and pipework which may become hot.
 
−
 
 
−
In the case of maritime transport, the IMO (International Maritime Organization) "Code of Safe Practice for Solid Bulk Cargoes" must be complied with.
 
−
 
 
−
==Risk factors==
 
−
<b>Temperature</b><br>
 
−
Favorable travel temperature: 5 - 25°C
 
−
 
 
−
Up to a temperature of 25°C, meal may be loaded irrespective of the external temperature. At elevated external temperatures, the product temperature must be no more than 10% higher than the external temperature. Continuous temperature measurements should be taken during loading of the cargo. In tropical ports, temperatures of 25 - 55°C may occur in the products to be loaded.
 
−
 
 
−
The temperature must accordingly also be measured at various depths in the hold during the voyage. If the temperature rises above 55°C and any further increase is observed, countermeasures must be taken, e.g. tight closing of all hatch openings and injection of CO<sub>2</sub> or inert gas (see RF Self-heating). Since extraction meal is deoiled by means of solvents, use of CO<sub>2</sub> should be maintained until any fire hazard has been overcome and ignition of the solvent vapors by static electricity has been prevented.
 
−
 
 
−
The enzymes which initiate and intensify fat degradation and thus the self-heating process reach optimum levels of activity at temperatures of 35 - 40°C, i.e. temperatures which are easily reached within the heaped cargo. The travel temperature should thus be between 5 and 25°C. Temperatures of up to 30°C are also admissible for short periods. However, these conditions are difficult to maintain during an ocean voyage, as a consequence of which very careful attention must be paid to ensuring that the critical water content of the product is not exceeded in order to avoid self-heating to the greatest possible extent.
 
−
 
 
−
<b>Humidity/Moisture</b><br>
 
−
[[Copra]] extraction meal requires particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).
 
−
 
 
−
{|
 
−
|-
 
−
|style="width:250px;"|<b>Designation</b>
 
−
|style="width:150px;"|<b>Humidity/water content</b>
 
−
|-
 
−
| Relative Humidity
 
−
| 70%
 
−
|-
 
−
| Water content
 
−
| 5 - 10%
 
−
|-
 
−
| Maximum equilibrium moisture content
 
−
| 70%
 
−
|-
 
−
|}
 
−
 
 
−
The meal must be protected from all forms of moisture (seawater, rain and condensation water), since moisture encourages mold, mustiness and self-heating.
 
−
 
 
−
Moisture promotes self-heating brought about both by hydrolytic/enzymatic degradation and by microorganisms and may be the result of an excessively high product water content or alternatively of external influences (excessively high relative humidity (critical equilibrium moisture content 75%), water splashes, rain). Copra extraction meal is also highly susceptible to mold growth due to an excessively high water content.
 
−
 
 
−
At a water content of < 5%, there is a risk of oxidative fat cleavage, dust formation/dust explosions and self-heating.
 
−
 
 
−
<b>Ventilation</b><br>
 
−
Copra extraction meal requires particular temperature, humidity/moisture and ventilation conditions.
 
−
 
 
−
Recommended ventilation conditions: surface ventilation.
 
−
 
 
−
Solvent vapors from extraction meal are heavier than air and do not take the form of surface vapors; as a result, they cannot rise upwards and be dissipated by surface ventilation. They may theoretically be eliminated by ventilation only if the temperature of the cargo rises due to self-heating, causing the vapors to rise in the cargo, in which case, however, direct surface ventilation would be inappropriate (see RF Self-heating).
 
−
 
 
−
In order to avoid moisture damage on the surface of the cargo (cargo sweat), ventilation must not be performed with cold external air. The ventilation system must then be switched to return air.
 
−
 
 
−
No access is permitted to the holds until they have been adequately ventilated and a gas measurement has been carried out. Since the solvent vapors are denser than air, they may have accumulated in the lower parts of the hold.
 
−
 
 
−
A certificate stating residual oil content, water content and maturing time should be demanded from the consignor.
 
−
 
 
−
If the oxidation processes under way in the hold are vigorous, it is not possible to dissipate the quantity of heat generated by ventilation. This particularly applies if a sub-batch susceptible to oxidation with a low water content is loaded next to a sub-batch with a high moisture content.
 
−
 
 
−
<b>Biotic activity</b><br>
 
−
Copra extraction meal displays 3rd order biotic activity.
 
−
 
 
−
It belongs to the class of products in which respiration processes are suspended, but in which biochemical, microbial and other decomposition processes still proceed.
 
−
 
 
−
Care of the cargo must be aimed at limiting the autoxidative fat cleavage process and so preventing possible self-heating of the product.
 
−
 
 
−
<b>Gases</b><br>
 
−
An increase in CO<sub>2</sub> and CO content in the hold air indicates that a cargo fire has begun. CO<sub>2</sub> has a smothering action on the seat of the fire because it displaces oxygen.
 
−
 
 
−
The vapors of the solvent used during production are denser than air and may thus accumulate in the lower parts of the hold.
 
−
 
 
−
<b>Self-heating / Spontaneous combustion</b><br>
 
−
Oil content: 0.1 - 1.5%
 
−
 
 
−
Copra extraction meal readily becomes rancid.
 
−
 
 
−
Copra extraction meal is liable to the risk of self-heating/spontaneous combustion.
 
−
 
 
−
Copra extraction meal is assigned to class 4.2, pursuant to the IMDG Code. All types and varieties of pellets, expellers and extracts fall within the class "Seed Cake" under UN numbers 2217 and 1386.
 
−
 
 
−
Due to the use of solvents, extraction meal is largely deoiled, as a result of which the oil content is relatively low in comparison with expeller, generally being < 1.5%.
 
−
 
 
−
Smoking/open flames are prohibited during loading, discharge and access to holds.
 
−
 
 
−
Causes and promoting factors of self-heating are moisture, oxygen, high fiber content and grain size. However, the residual vapors of the flammable solvents used for extraction are a hazard with extraction meal. Care must be taken to ensure that the extraction meal contains virtually no solvent residues.
 
−
 
 
−
The maturing time before ocean transport is of great significance to the promotion of self-heating processes in pressing residues, with both excessively short and excessively long maturing times possibly being disadvantageous. On acceptance, extraction meal should thus exhibit temperatures which are only insignificantly (approx. 10%) above external air temperature. It must be ascertained whether the batch is from the previous year's production. Unfavorable storage conditions over the period prior to shipping may mean that the product is already at elevated temperature when it arrives on board. Continuous temperature measurements are thus required during loading of the cargo.
 
−
 
 
−
The main risk for transport of any cargo which has heated ashore is that the product is loaded at temperatures of above 55°C and retains this temperature in the hold and, due to the poor thermal conductivity of the product, areas with a permanent heat build-up form for the entire duration of transport. The longer the duration of transport, the greater are the consequential losses arising from heating.
 
−
 
 
−
In the areas with a heat build-up of above 60°C, the autoxidation process of the feedstuff containing residual oil gradually begins and continues as the unsaturated [[fatty acids]] oxidize. The hot spots do not spread much further. The product does, however, dry out, as a result of which moisture migrates upwards from below and water vapor collects in the space between the surface of the cargo and the underside of the hatch covers or weather deck. This accumulation of water vapor combined with maximally airtight hatch covers is the most effective method of fighting fire, as any external supplies of oxygen are blocked off.
 
−
 
 
−
Pursuant to the IMDG Code/IMO, ships must be equipped with systems for injecting CO2 or inert gas.
 
−
 
 
−
The poor thermal conductivity of extraction meal is also of significance to self-heating. Self-heating may occur simultaneously at various points within the cargo and continue to such an extent that carbonization (release of hydrogen, leaving carbon behind) occurs. The resultant fine-pored carbon has the characteristic of starting to smolder when exposed to oxygen.
 
−
 
 
−
Due to the poor thermal conductivity of the product, temperature measurements to detect seats of risk are very difficult. Numerous measurements must be performed and some must also be taken within the heap. Surface measurements alone are not adequate.
 
−
 
 
−
The poor thermal conductivity also explains late detection of the seat of a fire. The particular risk is that the cargo burns within the heap without generating appreciable quantities of smoke. The seat of the fire carves out a cavity with the result that fatal accidents may occur when someone steps onto the surface of the cargo and breaks through into such cavities.
 
−
 
 
−
In order to be able to detect a cargo fire in good time, it is recommended to make regular gas measurements of the hold air. A rapidly rising CO2 content indicates increased microbial activity combined with evolution of heat within the cargo. This evolution of heat ultimately leads to the spontaneous combustion of the cargo, with evolution of carbon monoxide (CO). The presence of CO gas is considered the most reliable indication of a fire. Levels of 0.002 - 0.005 vol.% of CO in the air are deemed normal, with values rising to above 1 vol.% in a cargo fire.
 
−
 
 
−
On unloading, small flames may appear on the exposed surface of a heated cargo: volatile gases which have formed in the cargo over the course of self-heating and have a flash point of around 60°C have spontaneously ignited. These flames do not cause the remainder of the cargo to burn as the ignition temperature of most organic cargoes is of the order of 300 - 500°C. If such small flames or glowing areas of the surface occur in isolated areas, it is helpful to tip the last grab load back down into the area of the hold concerned, so smothering the flames.
 
−
 
 
−
The subsequent phases of self-heating possibly culminating in a cargo fire and the action to be taken are described under Feedstuffs ([[self heating]] process).
 
−
 
 
−
It is possible to conclude from characteristics observable in the ship's hold, such as temperatures, appearance and odor of the cargo, whether the product was loaded at too high a temperature and whether it has undergone self-heating with microbial spoilage and subsequent autoxidation.
 
−
 
 
−
 
 
−
The following features must be observed and recorded for this purpose:
 
−
 
 
−
* the flow behavior of the cargo in the heap (caked, free-flowing)
 
−
* the color of the product (normal, brown to black) and the distribution of color differences in the product in the hold
 
−
* the odor of the product (normal, healthy, fresh, musty, burnt)
 
−
* the temperature and appearance of the cargo at various depths in the bulk load
 
−
* the appearance of the cargo surface when the hatches are opened
 
−
* the appearance of escaping smoke/fumes (steam is white, smoke from overheated product with a temperature of above 90°C is black)
 
−
 
 
−
 
 
−
On the basis of this information, it is possible to conclude on the spot whether:
 
−
 
 
−
* the product was loaded too moist
 
−
* the product was loaded at too high a temperature after a drying process (toasting)
 
−
* the product was shipped shortly after production without complying with the maturing time
 
−
* biogenic self-heating has occurred during the voyage as a result of metabolic processes in microorganisms
 
−
* self-heating has occurred without a preceding biological self-heating process by chemical autoxidation of unsaturated [[fatty acids]]
 
−
* the product was loaded in a discolored state (brown to black) as a result of drying processes (toasting) performed during manufacture
 
−
 
 
−
<b>Odor</b><br>
 
−
<i>Active behavior:</i> Copra extraction meal has a slight, pleasant odor, but should not be stowed together with odor-sensitive products as residues of the solvent used may readily result in odor tainting. The odor of the solvent is, however, not always directly perceptible on the product. Rancid copra extraction meal has an unpleasant odor.
 
−
 
 
−
<i>Passive behavior:</i> Copra extraction meal is sensitive to unpleasant and/or pungent odors. Odor-tainted extraction meal is rejected by livestock (especially horses and cattle).
 
−
 
 
−
<b>Contamination</b><br>
 
−
<i>Active behavior:</i> Copra extraction meal causes severe dusting during cargo handling, such that there is a risk of dust explosion at dust/air ratios of 20 - 2000 g/m<sup>3</sub>.
 
−
 
 
−
<i>Passive behavior:</i> Copra extraction meal is sensitive to contamination by dust, dirt, [[fats]] and oils. The holds or containers should thus contain no residues of previous cargoes, such as [[ores]], minerals, chemicals, salts, fertilizers.
 
−
 
 
−
<b>Mechanical influences</b><br>
 
−
No risk.
 
−
 
 
−
<b>Toxicity / Hazards to health</b><br>
 
−
An increase in CO<sub>2</sub> and CO content in the hold air indicates that a cargo fire has begun. Danger: Risk of asphyxiation and poisoning on inhalation. No access is permitted to the hold until it has been adequately ventilated and the atmosphere tested with a gas detector. The CO content may rise from 0.002 - 0.005 vol.% to 1 vol.%. The lethal dose is approx. 0.1 vol.%.
 
−
 
 
−
Caution is required in the event of contamination by [[castor seeds]] (toxic).
 
−
 
 
−
<b>Shrinkage/Shortage</b><br>
 
−
Slight losses (trickle losses) may occur during cargo handling.
 
−
 
 
−
<b>Insect infestation / Diseases</b><br>
 
−
Copra extraction meal is rarely infested by insects. On extended storage, there is a risk of mite infestation, which is promoted by heat and moisture.
 
−
 
 
−
If required by the consignor or import regulations, fumigation (e.g. with [[methyl bromide]]) must be performed.
 
−
 
 
−
A form of dried [[coconut]]. This is meal, scoured by way of a chemical solvent and subsequently pressed into cylindrical little sticks. It only contains 1% oil.
 
−
Depending on the oil and moisture content it may be necessary to observe a drying period of at least 10 days before shipping this product Mostly shipped in bulk.
 
−
 
−
<b>Stowage summary</b><br>
 
−
* In a dry location.
 
−
* Care to be taken to provide good surface [[ventilation]].
 
−
* Free from bulkheads and piping, radiating heat
 
−
* Do not use naked lights.
 
−
* Smoking prohibition to be maintained.
 
−
* Ventilation openings are to be fitted with spark arresting wire netting.
 
−
 
 
−
IMDG Class 4.2
 
−
 
 
−
 
 
−
Note:
 
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[[Category: Products]]
 
[[Category: Products]]
 
[[Category: Seeds and agriproducts]]
 
[[Category: Seeds and agriproducts]]

Latest revision as of 13:08, 10 April 2013

Infobox on Copra Extraction Meal
Example of Copra Extraction Meal
Copraexpeller.jpg
Facts
Origin This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.
  • Europe
  • Africa: Mozambique
  • Asia: Philippines, Indonesia, India
  • America
  • Australia
Stowage factor (in m3/t) 2.0 - 2.3 m³/t
Angle of repose -
Humidity / moisture
  • Relative humidity: 70%
  • Water content: 5 - 10%
  • Maximum equilibrium moisture content: 70%
Oil content 0.1 - 1.5%
Ventilation Copra extraction meal requires particular temperature, humidity/moisture and ventilation conditions.
Recommended ventilation conditions: surface ventilation.
Risk factors Copra extraction meal readily becomes rancid.
Copra extraction meal is liable to the risk of self-heating/spontaneous combustion.

Copra Extraction Meal

Description

Coconut Oil is obtained by extracting the oil contained in copra. The residue is generally called copra cake, sometimes it is called copra meal. Coconut oil is used for food and for industrial purposes. Edible oil, by international standards should have less than 0.1% free fatty acid content. The oil obtained from good quality copra, with a free fatty acid content of < 0.1%, is used as cooking oil without any further processing. Even if the free fatty acid content is 3-5%, the international standard of < 0.1% can be obtained by refining and deodorizing. Edible oils are either used as cooking oil (frying oil) or processed further into filled milk, table margarine and baker's margarine.

In industry, coconut oil is used for manufacturing toilet and laundry soap. In its original or modified form, it is used as a vehicle in the paint and varnish industry. Coconut oil is also processed into methyl esters, Fatty Acids and fatty alcohols. These intermediate products are raw materials for manufacturing detergents, surfactants, emulsifiers, plasticizers and various other organic products which are bio-degradable. Copra cake is used in blending animal feed.

Expellers are the residue from processing by the continuous screw process, with an oil content of between 1,5-7%, but sometimes more if old machinery has been used.
Extractions are the residue after solvent extraction of the oil, the remaining oil content is >1,5%. Usally in the form of regular grain-sized pellets.

Extraction Technology, Dry Processing:
Oil extraction from copra is carried out by two methods: mechanically by pressing; or by use of solvents. Mechanical and solvent extraction uses standard technology that has been developed in the vegetable oil industry. For Oil Seeds such as copra which have a high oil content, mechanical extraction is efficient and economical. For oil seeds with low oil content or for further oil extraction from copra cake, the solvent extraction method is more suitable. The residual material from solvent extraction is called copra meal. Oil extraction involves five basic steps: copra storage; preparation of copra; oil extraction - full press, prepress - solvent, and full solvent methods; processing of extracted oil; processing of cake or meal and storage of products.

Full press method:
In the full press method of oil extraction, maximum pressure is applied to the material and sufficient time is allowed for the oil to escape. The temperature of the material should not be allowed to rise to a level where the oil darkens due to overheating. The pressure is applied to the material between the screws and the cage of slitted steel bars. Pressing may be done in a single or in double stages. By adjusting the clearance in the choking device, the thickness of the cake can be controlled. When the clearance is reduced to decrease the thickness of the cake, the pressure applied is increased. To prevent overheating the oil, the shaft is usually hollow for water cooling, and the oil is sprinkled over the cage bars.

Prepress-solvent method:
In the prepress-solvent process, the oil is partially extracted by preliminary low pressure mechanical extraction, and then subjected to solvent extraction to remove most of the residual oil. The oil content of the initial copra material is around 70%; after the mechanical prepress extraction, the residual oil content in the prepressed cake is 16 - 20% for optimum operation. After full press extraction, the oil content in the residual copra cake is 6 - 10%, depending upon efficiency. The equipment used for prepressing is similar to expellers used for full pressing, but adjusted for less pressure and therefore it has a higher throughput.

Full solvent method:
In solvent extraction, oil in the material is leached with a solvent (where the oil dissolves in the solvent) whereas the insoluble meal is retained unaffected. The extent of extraction depends upon the kind of solvent, the temperature of solvent, the ratio of solvent to meal, the number of extraction stages, the shape of particles, the porosity of the material, and the contact duration. The most common solvent used is Template:Hexane because of its price, low toxicity, suitable boiling point for recovery and handling, and its availability. Solubility of oil in hexane increases with temperature.

The resulting streams from solvent extraction are: the micella or oil, solvent solution, and the extracted meal which comprises the meal, some solvent and a little residual oil. The solvent in the meal is removed by heating to boil off the volatile solvent, and the solvent is recovered by condensation. The solvent from the micella is removed and recovered by evaporation and condensation. Traces of solvent left in the meal and the oil are removed by steam-stripping under reduced pressure.

The equipment for solvent extraction consists of two general types; the roto-cell type with cells revolving around a vertical axis, and the basket type with baskets travelling horizontally while the solvent is sprayed over the material in counter-current flow. In the full solvent process, the prepared copra is first subjected to a first extraction (percolation), using the weak micella from the second extractor as starting solvent, and producing the strong micella for oil recovery. The extracted meal is then flaked and subjected to a second extraction (immersion) which uses fresh solvent as starting solvent and produces the weak micella solvent for the first extractor. The solvent with the extracted oil is removed in a Desolventizer-Toaster (DT) which is either of the multi-decked vertical design with steam heated pans and paddle scrapers, or the horizontal barrel type with rotating conveying paddles attached to a horizontal shaft, and steam jacketed walls. These are equipped with condensers for solvent recovery and scrubbers to remove dust entrained in the vapours. In some designs, the heat with the vapours leaving the DT is used to pre-concentrate the micella prior to evaporation of the micella.

The solvent with the micella is recovered, first by an evaporator, usually of the falling film type, where hexane is distilled off by indirect steam heating, and subsequently by a stripping column where traces of hexane in the oil are stripped by steam under vacuum. The water-hexane vapours from the stripper are condensed and collected in a water-hexane separator where hexane is separated by gravity from the water. It is decanted and reused in the extraction. Vent vapours of hexane from the extractors and condensers are recovered in a vent recovery system where hexane is absorbed by mineral oil. Hexane is recovered from the mineral oil by stripping, and recycled to the extractor.

Processing extracted oil:
Processing the extracted oil is the next basic step in the oil extraction technology. Oil from the expellers contain substantial quantities of solids (foots) that should be removed before the oil is pumped into the storage tanks. The oil is cleaned first by settling and screening and subsequently by filtration. The screening equipment is a rectangular steel tank equipped with a continuous drag chain conveyor with scraper blades, which scoop the settled solids and lift them over a fine screen for drainage at one end of the screening tank, after which they are conveyed back to the expellers to be mixed with the copra. The filtering equipment generally consists of a plate and frame filter press with canvass filtering media. Some factories use leaf filters with perforated steel filtering leaves. The foots or filter cake from the filters are recycled to the expellers for oil extraction. The oil from solvent extraction is free of solids. It leaves the stripping column at 120°C and is cooled and pumped into the storage tanks through an oil meter.

Processing cake or meal:
Copra cake leaving the expellers has a temperature of about 110 °C and is cooled in a cake cooler. The cake cascades down the cooler baffles and is cooled by a cross-flow of cooled air from blowers. After cooling, it is ground to fine particles by hammer mills or disc mills. The ground cake is bagged for local use or pelletized for export. Pelletizing requires additional equipment which small plants cannot afford. However, cake or meal for export has to be pelletized for safer and easier handling and conveying. Prior to pelletizing, the cake has to be moistened to about 12% moisture and then fed to the pellet mill. Moistening in this manner improves pelleting property, and is required for export. The oil content of copra cake should be around 6 to 10% and moisture not higher than 12%. For Copra Expeller, the oil content is approx. 1,5-7% and for copra meal 0.5 - 1,5% depending on the efficiency of solvent extraction. Due to absorption, the moisture level rises during storage.

Storage of products:
The unpelletized copra cake should be bagged in woven sacks and stacked about 10 high on wooden pallets. It is hazardous to store unpelletized cake in bulk for long periods. The piles of unbagged meal should be kept small and turned over as frequently as necessary to prevent spontaneous combustion.

The (hot) finished expellers leave the production plant with a variable moisture content. After pressing, the expellers are cooled and, since they are in large pieces, they are ground and adjusted to a water content suitable for storage and transport. The ground products are then held in intermediate storage in silo cells or sent for transport.

Applications

Copra cake/expeller/meal is used as an ingredient in blending animal feed, due to the presence of oil, protein and carbohydrates. Copra cake from poor quality copra has a limited market due to its degraded condition and the presence of aflatoxin.

Shipment/storage

Upon shipment, the copra produce should be accompanied by certificates stating the moisture, residual oil content and the maturing time of the product. It should also be stated that the product really is expeller and not extraction meal (extracting agent/solvent content). Oil contents of < 1.5% are indicative of extraction meal.

Overheating during the production process, or subjecting the product to pro longed storage, may be manifested by brown or reddish to black discoloration. Expeller/Extraction meal is mainly transported as Bulk Cargo.

Favorable travel temperature: 5 - 25°C.
At elevated external temperatures, the product temperature must be no more than 10% higher than the external temperature.
In tropical ports, temperatures of 25 - 55°C may occur in the products to be loaded.

If the cargo temperature during the voyage rises to >55°C and any further increase is observed, adequate measures must be taken, e.g. tight closing of all hatch openings and injection of CO2 or inert gas may have to be considered.
Stow away from heat sources (i.e. engine room bulkheads, heated fuel tanks, etc.).

Note:
See also advice on overseas shipment of Seedcake and Expellers and Extractions

Risk factors

- Humidity/Moisture
- Self-heating / Spontaneous combustion
- Contamination
- Toxicity / Hazards to health
- Shrinkage/Shortage
- Insect infestation / Diseases

Note: Reference is made to the relevant IMO regulations on hazardous cargo.

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