GB2154318A - Coal carbonisation test - Google Patents
Coal carbonisation test Download PDFInfo
- Publication number
- GB2154318A GB2154318A GB08404222A GB8404222A GB2154318A GB 2154318 A GB2154318 A GB 2154318A GB 08404222 A GB08404222 A GB 08404222A GB 8404222 A GB8404222 A GB 8404222A GB 2154318 A GB2154318 A GB 2154318A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sample
- coal
- reactivity
- test
- test temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003245 coal Substances 0.000 title claims abstract description 24
- 238000003763 carbonization Methods 0.000 title description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000000571 coke Substances 0.000 claims abstract description 18
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 13
- 230000004580 weight loss Effects 0.000 claims abstract description 7
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 35
- 239000000203 mixture Substances 0.000 claims description 10
- 230000009257 reactivity Effects 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000011261 inert gas Substances 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 2
- CNJLMVZFWLNOEP-UHFFFAOYSA-N 4,7,7-trimethylbicyclo[4.1.0]heptan-5-one Chemical compound O=C1C(C)CCC2C(C)(C)C12 CNJLMVZFWLNOEP-UHFFFAOYSA-N 0.000 claims 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000007789 gas Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 206010010071 Coma Diseases 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/22—Fuels; Explosives
- G01N33/222—Solid fuels, e.g. coal
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
Micro-reactivity of cokes can be estimated by carbonising a small sample of finely divided coal until constant weight at a desired test temperature, then passing carbon dioxide over the sample at the desired test temperature and measuring weight loss in a given time.
Description
SPECIFICATION
Coal carbonisation test
This invention concerns a coal carbonisation test, more especially it concerns a test which gives information on coke micro-reactivity.
Considerable attention is currntly being paid to the reactivity to carbon dioxide of carbonised coals or cokes. A favoured test for the reactivity of coke is the Nippon Steel Corporation (NSC) method (COMA Yearbook 1980, 87), involving determining the percentage weight loss of a 200 g sample of a closely sized lump coke (20 + 1 mm) in carbon dioxide at 1 100'C for 2 hours. A special standard apparatus has been devised for carrying out the NSC method; not only is the apparatus expensive but the method is time-consuming and labour-intensive. Thus to assess a coal or coal blend for commencial use, test cokes have to be prepared and this requires up to one day. Thereafter, the method itself requires skilled laboratory personnel.It would be of considerable assistance to coke oven plant operators if a simpler, quicker and cheaper test could be devised capable of being carried out by relatively unskilled personnel at the plant and enabling plant management to predict and monitor the likely performance of a coal feed or blend on the commercial scale before coke is actually made. It would be most advantageous if any test method could be found to bypass the need to make test cokes in a test or pilot oven. We believe that we have found a quick and simple method which avoids most if not all of the drawbacks of the NSC method, yet gives results which correlate very well with those of the NSC method.
Accordingly, the present invention provides a method for assessing the micro-reactivity of coke, which comprises taking a small representative sample of a finely divided coal or coak blend, carbonising it under an inert gas by heating until a constant weight is obtained at the desired reactivity test temperature, passing carbon dioxide over the carbonised sample at the desired test temperature and measuring the weight loss in a given time.
It can be seen at once that the starting material for the method of the invention is not a coke but a coal. We do not believe that this has previously been suggested although it offers particular advantages which will become clearer hereinafter. The coal or coal blend is preferably ground or crushed to a suitable size; for example in tests which are found to give good correlation with the NSC method a suitable size range is 72-120 BS sieve sizes (212-125 yam), which is within a size range frequently prepared in the UK industry for proximate analysis of the feed coal(s). The weight of the sample is not critical to the present invention, and successful tests have been carried out with as little as 1 50 mg of coal, although it is envisaged that a test method suitable for plant use would use about 10 g.However, it is important to ensure that the sample is representative, and known methods exist for sampling to give a statistically representative sample, normally involving a riffling procedure.
The coal or blend sample is heated to a preselected temperature under an inert gas, preferably under a stream of the gas which is conveniently nitrogen, although any inert gas may be used. The preselected temperature would normally be in the range 900 to 1 200 C, and in the NSC method is 1 1 00to.
The rate of heating is also conveniently that met with in conventional carbonisation in an oven, of the order of 5 C/min. It may be possible, if desired, to speed up the test by heating at a faster rate, especially in the postplastic phase above about 500"C, but because the method can operate with small samples the problems of bulk heating are avoided, and carbonisation times are of the order of 3 > hours instead of 17-20 hours in coke ovens. If the coal(s) being tested are strongly caking, it is desirable to physically separate the individual particles of coal to prevent agglomeration. Since the method of the invention is a micro-reactivity test and not intended to simulate or give information on coke bulk reactivity, it is necessary only to form a clear rather than a coke in which fusion has taken place.
The reaction of the carbonised sample with carbon dioxide is suitably carried out by passing a stream of CO2 over the sample. Preferably, the weight of the sample is constantly monitored against time, but the sample may be weighted before and after a known period of CO2 treatment. The NSC method specifies weight before and after passing CO2 for 2 hours; we have found that the CO2 treatment may be carried out until a 20% weight loss or for a fixed time since weight loss is linear with time, providing that the same procedure is used for comparisons.
Preferably, the method of the invention is carried out in a furnace in which the sample of coal or blend can be heated and exposed to, in turn, the inert gas and CO2, and in which the sample can be weighted continu ousiy or at the necessary points in the procedure.
We have also noted that there is a closely linear relationship between NSC reactivity results and post-reaction strengths (involving the tumbling of a coke which has undergone reaction with CO2, under standard conditions and measuring the breakage). Accordingly, we believe that the method of the present invention can be used to give useful information on post reaction strength as well as micro-reactivity.
The invention will now be described by way of example only.
EXAMPLE
Representative samples of a variety of coals and coal blends were crushed and sieved to yield finely divided coal in the size range 212-125,um and 1 50 mg samples were carefully taken. The samples were placed in the sample holder of a commercial thermobalance and then heated under flowing nitrogen (400 ml/min) at 5'C/min to the temperature at which the reactivity measurements were to be made, 1100 C. The thermobalance provides a continuous reading of weight and when the temperature and weight of the sample had stabilised, the nitrogen was replaced by CO2 for 10 minutes.Each test could be completed within 4 hours, compared to at least one day normally required to carry out the NSC method by coking in a pilot oven then carrying out the NSC specified procedures.
For comparison purposes, the same coals and blends were coked in a 250 kg pilot oven by crushing the raw coal so that 85% passed through 3.35 mm screen and charging to the oven in the wet state (9% moisture). The pilot oven was gas heated, the flue side of the walls being maintained at 11 80"C. After 1 7 hours nominal carbonisation time, the charge was discharged and water quenched. The charge centre temperature was about 1030"C upon discharge. 200 g samples of the resulting cokes were tested in accordance with the
NSC method.
The results of NSC reactivity and microreactivity according to the present invention are plotted in the accompanying Figure. The slope of the best straight line gives an equation:
NSC reactivity = 1.152 MR + 9.050 where MR is the % weight loss after 10 minutes in the method of the invention as described above.
A correlation coefficient of 0.936 is found, and we believe that the method offers a valuable alternative to the NSC method.
While the method of the invention describes specifically an alternative to the NSC method, it is believed that the invention offers alternatives to many other reactivity tests carried out at local level to assess cokes and carbonised solid fuels of many types.
Claims (7)
1. A method for assessing the micro-reactivity of coke, which comprises taking a small representative sample of a finely divided coal or coal blend, carbonising said sample under an inert gas by heating until a constant weight is obtained at the desired reactivity test temperature, passing carbon dioxide over the carbonised sample at the desired test temperature and measuring the weight loss in a given time.
2. A method according to claim 1, wherein the coal or coal blend sample is of a particle size in the range 212-125 jum.
3. A method according to claim 1 or 2, wherein the test temperature is in the range 900 to 1200'C.
4. A method according to claim 1, 2, or 3, wherein the sample is heated at a rate of approximately 5 C/min.
5. A method according to any one of the preceding claims, wherein the sample is weighed continuously in the heating and the caron dioxide treatment steps.
6. A method according to claim 5, carried out in a thermobalance.
7. A method according to claim 1, substantially as hereinbefore described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08404222A GB2154318B (en) | 1984-02-17 | 1984-02-17 | Coal carbonisation test |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08404222A GB2154318B (en) | 1984-02-17 | 1984-02-17 | Coal carbonisation test |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8404222D0 GB8404222D0 (en) | 1984-03-21 |
| GB2154318A true GB2154318A (en) | 1985-09-04 |
| GB2154318B GB2154318B (en) | 1987-08-05 |
Family
ID=10556758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08404222A Expired GB2154318B (en) | 1984-02-17 | 1984-02-17 | Coal carbonisation test |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2154318B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0558131A2 (en) * | 1992-02-28 | 1993-09-01 | Norsk Hydro A.S. | Method for deciding the reactivity and soot index of carbon products and equipment therefor |
| EP0558130A2 (en) * | 1992-02-28 | 1993-09-01 | Norsk Hydro A.S. | Apparatus for analysing carbon products |
| CN113252840A (en) * | 2021-05-19 | 2021-08-13 | 重庆大学 | Testing arrangement of simulation coal spontaneous combustion and process of putting out a fire |
-
1984
- 1984-02-17 GB GB08404222A patent/GB2154318B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0558131A2 (en) * | 1992-02-28 | 1993-09-01 | Norsk Hydro A.S. | Method for deciding the reactivity and soot index of carbon products and equipment therefor |
| EP0558130A2 (en) * | 1992-02-28 | 1993-09-01 | Norsk Hydro A.S. | Apparatus for analysing carbon products |
| EP0558130A3 (en) * | 1992-02-28 | 1994-08-03 | Norsk Hydro Technology | |
| EP0558131A3 (en) * | 1992-02-28 | 1994-08-03 | Norsk Hydro Technology | |
| CN113252840A (en) * | 2021-05-19 | 2021-08-13 | 重庆大学 | Testing arrangement of simulation coal spontaneous combustion and process of putting out a fire |
| CN113252840B (en) * | 2021-05-19 | 2022-05-13 | 重庆大学 | Testing arrangement of simulation coal spontaneous combustion and process of putting out a fire |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2154318B (en) | 1987-08-05 |
| GB8404222D0 (en) | 1984-03-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930217 |