The grain stability of calcined petroleum coke determines the resistance to breakdown of +4 mm particles used in the manufacture of carbon anodes for use . Designation: D/DM − Standard Practice for. Collection and Preparation of Coke Samples for Laboratory Analysis1 This standard is issued under the. ASTM D Standard Practice for Collection and Preparation of Coke Samples for Laboratory Analysis.
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Quality control of charcoal and by-products 8. Large consumers, such as the steel or electrical industries, have their own quality control laboratories staffed by trainee operatives. The laboratory staff must be familiar with the different standards used for quality control of charcoal and by-products. The buying specification of large industrial users and others will refer to various parameters measured in the process of quality control.
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The acceptability of the product will be determined by it’s compliance with the values laid down in the specification. Price variations may also apply where standard quality indicators are not met. Fixed carbon content is an important parameter in steel making charcoal since this is the agent which reduces the iron ore to metallic iron and limits which must be met are often specified. Screen size, ash content and friability are also often specified by large buyers.
Standards for charcoal testing are derived from fuels such as coal or coke and, in some cases, are modified to apply specifically to charcoal analysis.
Such modifications must be mentioned in the charcoal analysis report. Testing must follow standardized methods in all cases to ensure that the results can be compared and the analysis repeated. Various countries have developed their own standard methods for quality control of solid fuels and these are applied with some modifications to the testing of charcoal.
The testing methods for by-products are derived from standard analytical procedures for liquid chemicals and gaseous fuels. It is not necessary to astj all the standards which are used but merely to indicate a typical system. The most important of these test methods which apply to charcoal testing are listed on the following page. ASTM D usually modified for charcoal.
Used for charcoal briquettes. Continue drying and reweigh at one-hour intervals until the loss is not more than 0. The loss of weight will be calculated as a percentage of the initial wet weight. In the case of solid wood, pieces of an approximate size of 5 x 5 x 5 cm. Method for charcoal and charcoal briquettes.
Crush sample in e346 porcelain mortar and accurately weigh 3 grammes. Drying and weighing procedures as above. Crush or grind sample and weigh accurately 3 f346 in a platinum or porcelain crucible with a lid.
Check weight and temperatures at intervals until weight loss is under 0. The difference between initial weight and weight of d36 after combustion will be expressed as a percentage of the initial weight and represents the ash content. A correction can be made for moisture content to express ash on a moisture free basis.
For charcoal and charcoal briquettes. Prepare sample as above.
According to estimated ash content accurately weigh three or five grammes in a platinum or porcelain crucible with lid. Continue procedure as described for raw material above. By heating charcoal with exclusion of air oxygen volatile matter and gases are expelled. These gases are called volatiles and consist of tarry vapours and non-condensible gases. Preparation of charcoal sample.
ASTM D346/D346M – 11
Crushing is done manually in a porcelain mortar with a pestle. Grinding is not recommended because the heat generated would already drive off part of the volatiles. Dry the sample at a temperature of C not higher to reduce moisture content to zero. Accurately weight one gramme of the powdered sample in a platinum preferable or porcelain crucible aastm a lid with the following dimensions: The lid should have a hole in the centre of a diameter of 1.
The rim of the lid must comfortably overlap the rim of the crucible to prevent intake of air. Place the crucible in a wire triangle firmly on a tripod and heat the bottom gently with a Bunsen burner, placed at a distance of not less than 6 cm from the crucible. After minutes, open the gas adjusting screw and the air control of the Bunsen burner to full capacity and continue heating until the small flame above the astn of the lid has ceased. This indicates that all volatile matter has been driven off.
Put the hot crucible into a desiccator with calcium chloride as a desiccant, until the sample has cooled. The difference between the initial weight represents the volatile asmt.
The value for the fixed carbon is calculated as follows: The most common method being calorimetric combustion of the charcoal with the addition of diluted sodium hydroxide to convert sulphur to sulphates, which are largely precipitated with barium chloride as barium sulphate. Accurately weigh one gramme of the dry powdered sample and insert it into the calorimeter following the instructions given by the equipment supplier.
Combustion takes place under an excess of oxygen and the pressure is kept at 20 atm. After ignition, the calorimeter has to be shaken for about half an hour.
Release pressure and discharge the combustion residues by several rinsings with water into a beaker the contents of the calorimeter must be r346 transferred. A white precipitate of barium sulphate will immediately appear. After cooling, the contents of the beaker are poured through a weighed glass filter which collects the barium-sulphate precipitate. After rinsing the filter several times with distilled water, oven dry it and weigh.
Calculate barium sulphate content by weight difference. For analysis, a set of standard screens with different mesh sizes are used. The most common set is: Accurately weigh grammes of dried sample and put it on screen No. Shake the whole screen set for two minutes. Then weigh the residue remaining on each screen.
Note down the different weights in percentage of the total initial weight in the following order: The figures in per cent indicate the reduction in size suffered during the test. Therefore, the lower the per cent figure the better the charcoal.
The drum is rotated at 24 rpm for one hour total 1, rev. The effect of tumbling on the charcoal is tested as follows. The charcoal is first sieved by hand to remove material which passes a 1. This is to prevent the finer charcoal cushioning the effect of rumbling on the coarse material during the test. After rumbling the charcoal is sieve-analysed to measure the size reduction which has occurred.
These results are combined with the sieve analysis of the fine material excluded from the tumbler test to give a total evaluation of the charcoal’s quality.
Pour the charcoal sample as received from the plant, or storage a little at a time into a ml calibrated cylinder. When the ml calibration mark has been reached stop and weigh the charcoal fines. The weight obtained multiplied by 10 gives the bulk density per litre.
The procedure can be astmm by using a machine for the shaking. They all operate according to the general scheme of comparison of the sample with a liquid of known viscosity. The most common test used in d46 determination of pyroligneous acid is the Engler-scale. Instructions are provided by supplies of laboratory equipment.
Special apparatus can be purchased. An oxygen calorimetric bomb is necessary for this test. But there are many which will be required only once a year or even less, particularly in a small plant. The test would be done by contract with a commercial testing authority, perhaps a university. Small-scale charcoal satm for economic reasons, engage the services of an existing laboratory, either through a university or privately.
The new charcoal producer quickly learns what can be done by himself and which part of the laboratory work can be contracted.
The charcoal maker engaging in export business may rely on his partners abroad, who are normally well equipped, and have capable staff to deal with problems which arise and provide customers with advice. A simple apparatus for these tests is shown in Fig. A capacity of about litres is adequate. The container is made of copper or stainless steel and constitutes in effect a small closed retort.
An offtake pipe leads through a condenser which collects the tars and pyroligneous acids produced from the thermal decomposition of the wood. Non-condensable gases may be collected and analysed but more usually are simply burned to waste. The yields of charcoal and liquid products can be easily measured and the effect of carbonising temperature studied.
The retort is filled to about 0. The retort should be heated gently with the burner flame to allow the moisture to be driven off and avoid overheating of the charge at any point. The rise in temperature is monitored with the thermocouple and allowed to rise to final temperature over a few hours. When the required temperature is reached the retort is allowed to cool to room temperature and the yield of charcoal, tars and pyroligneous acid measured by weighing.
The conditions in the small retort are not very similar to continuous large-scale retort systems.
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However, they have great value for 3d46 between various raw materials since the behaviour of known materials can be compared with new type raw materials or the effect of changing carbonisation temperature can be studied in a comparative way. The extensive data on the carbonisation of the various species of eucalypts quoted by 20 were obtained in this way and show how comparative studies of this type can serve as a guide in choice of raw material.
Small retorts of this type are conveniently heated by electricity which allows close control of temperature. Container made from wire cloth 3.