GB2211512A - Briquetting process - Google Patents
Briquetting process Download PDFInfo
- Publication number
- GB2211512A GB2211512A GB8823443A GB8823443A GB2211512A GB 2211512 A GB2211512 A GB 2211512A GB 8823443 A GB8823443 A GB 8823443A GB 8823443 A GB8823443 A GB 8823443A GB 2211512 A GB2211512 A GB 2211512A
- Authority
- GB
- United Kingdom
- Prior art keywords
- process according
- mix
- cement
- coal
- briquetting
- 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.)
- Withdrawn
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L5/00—Solid fuels
- C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
- C10L5/06—Methods of shaping, e.g. pelletizing or briquetting
- C10L5/10—Methods of shaping, e.g. pelletizing or briquetting with the aid of binders, e.g. pretreated binders
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
2211512 -11 CASE 4916 BRIQUETTING PRXESS The present invention concerns a
briquetting process. More especially it concerns such a process which gives improved green strengths in "cold" briquetting, that is, briquetting at temperatures of up to 1000C.
Our UK Published Patent Application No 2,187,754 discusses a variety of cold coal briquetting processes and discloses a useful process utilising a combination of molasses and inorganic hardening agent as binder. Our co-pending application No 87 21757 discloses a variation of the process of GB 2,187,754 in its use of concentrated sugar solutions. The disclosures of both these applications are incorporated herein by reference.
We have found that a great many cold briquetting processes. in which a water-containing binder is used, while apparently producing satisfactory briquettes of adequate final strength, and even acceptable to good burning properties. result in green briquettes of inadequate initial strength. That is to say, the briquettes, when emerging fram the briquette forming step, have a low crushing strength and are easily broken. In practice on the industrial scale, mechanical handling of the green briquettes results in undesirably high breakages and loss of complete briquettes, requiring 2 recycle of broken briquette pieces or the acceptance of less desirable and less valuable product.
It has now been discovered that the incorporation of minor quantities of a cement into a water-containing mixture of coal and binder, especially under the normal operating temperatures of industrial processing, yields worthwhile improvements in initial green strength. Ordinary Portland Cement (110PC11) has been proposed as a binder for solid fuel briquettes, but has required the addition of 5% or more by weight of the briquette mix of the cement, resulting in high total ash contents for the briquettes. We believe that for a variety of reasons, cement-bound briquettes have not been =mercially successful. Our present invention surprisingly requires only a limited quantity of cement, below that which would act as a successful binder, in combination with another binder, in order to improve initial green strength.
The present invention provides a process for the cold briquetting of fine coal, comprising mixing fine coal with a binder to produce a watercontaining briquetting mix, and characterised by the presence in the briquetting mix of up to 2% by weight of the mix of a cement, and briquetting the mix, whereby the initial green strength of the resulting briquettes is improved.
Although the process is naninally "cold", it is found that on the industrial scale the mix enters and leaves the briquette formation steps at a temperature above ambient, for example of the order of 600C. For example, it may be necessary to dry the fine coal by heating, before briquetting, and this mix retains sensible heat, or, depending upon the briquette formation step, friction and/ or compression may give rise to heating of the briquette during formation. It has been found that the present invention offers particular advantages as regards initial green strength if the briquetting step is carried out at temperatures above 500C.
Desirably, the binder is a combination of molasses and an inorganic hardening agent, or a sugar or starch solution and an inorganic hardening agent, and we refer to our prior applications mentioned above for examples of such binders. Other binders may, however, be used if these are water-based and produce briquettes which have unsatisfactory green strength.
The cement used is preferably OPCl which exhibits good results in tests and is readily available at low price, but other cements such as special portland cements, and high alumina cement may be used. Alternatively, Sorrel cement (which is based on magnesium oxide and magnesium chloride) may be used. It is recommended that the cement be pre-mixed with dry coal, either alone, or in combination with other hardening agents, prior to adding water-containing binders. Alternatively,, the cement may be added to wet coal if it is combined with dry binders such as starch, either with or without hardening agents. Specific cements and coal/binder mixes should be routinely tested to ensure that they are satisfactory and yield briquettes of the desired appearance and properties. Cement setting and hardening may be adjusted in known manner by mixing appropriate cements and/or by the incorporation of accelerators or retarders. Preferably, the cement is used in an amount of up to 1%, more preferably, in an amount of up to 0.5%, by weight of the mix. Good results in preliminary tests have been 4 achieved with amounts of cement of approximately 0.5% by weight.
Preferred coals are high rank non-caking coals, especially those having low smoke emissions such as anthracite. Desirably the coal is of a particle size mainly below 3mm, and anthracite duff is especially suitable. The invention is also applicable to coals for power stations or steam raising and to coal blends containing caking coal components and/or treated coals, eg by mild oxidation or pyrolysis. The coal may be crushed or be the direct product of coal cutting.
The briquetting step of the present invention includes all methods of forming agglomerates from fine coal, and these agglomerates may be of any size or shape according to market requirements. There may be mentioned forming agglomerates by extrusion, ringroll - or roll- pressing, die-pressing, rotary table pressing and pelletising, eg on a disc pelletiser.
The process preferably includes a hardening stage to permit the green briquettes to gain additional strength, depending upon the binder used. Hereinafter, reference will be made for convenience only to binders comprising molasses and an inorganic hardening agent. The green briquettes harden over a period of 1 to 3 days at ambient temperature to give adequate crushing strengths,, but the briquettes tend to have inadequate water resistance. However, the briquettes may be bagged in impervious sacks and allowed to further harden during storage. Preferably, however, a hot curing step is included to speed up the hardening stage and to make the briquettes water resistant, and this may be carried out at temperatures of the order of 200 to 3000C for up to an hour. Hot curing may be conveniently carried out by passing the briquettes on a conveyor through an oven, in an atmosphere which may contain nitrogen, carbon dioxidei water vapour and/or oxygen. It is to be noted that the hot curing step does not correspond to a carbonisation step, and thus not only are there energy savings, but the solid yield on a dry basis is very high. Additionallyr there is a reduced risk of pollution.
The water resistance of the briquettes may be improved by an additional treatment with a spray or bath of a water proofing agent. Several agents are known to have been proposed including, for example, aluminium acetate.
The present invention also provides briquettes formed using a process as described above.
The present invention will now be described by way of example only.
EXAMPLE 1
A fine anthracite, from South Wales, was prepared by crushing and screening to minus 3mm. The anthracite was admixed with 8% of mollasses, 1% iron ore and 1% phosphoric acid, by weight of the final canposition. The mixture was briquetted in a pilot plant roll press, for comparison with the same mixture together with additions of 0.25% and 0.5% of ordinary portland cement.
Briquette testing was carried out under laboratory conditions at ambient temperatures of 200C, and also after heating to a camT--rcial operating temperature of 600C. Crushing strengths according to standard tests were established for the green briquettes and also green briquette shatter indices for the various briquettes. the latter being a measure of the size of broken briquette pieces by measuring the quantity by weight retained on screens of the specified operative. The results obtained are presented below: 5 Cement Bricruette green strength(kg) Briquette shatter index(%) Addition temperature Ambient R by wt) Ambient 600C + 38mm + 22mm Nil 5.4 6.0 60 68 0.25 6.3 8.3 85 90 0.5 7.5 14.8 94 95 It is readily seen that the addition of quite small amounts of cement have a significant effect on green strength and shatter index.
is EXAMPLE 2
A briquette manufacturing plant was continuously operated using anthracite which was crushed and screened to minus 3MM. It was then mixed with molasses, iron ore and phosphoric acid as in Example 1 and the mixture was further mixed with 1% by weight of Portland cement. The resulting mixture was briquetted in a roll press and hot cured. It was noted that there was a reduction in breakage of the briquettes through mechanical degradation, and this reduction resulted in an average increase in product yield of 13%.
EXAMPLE 3
Example 1 was repeated except that 0.5% by weight of the final =position of xanthan gum was added. The addition of the gum had only a marginal effect upon the green crushing strength but produced 7 a significant improvement on green shatter strength, thereby imparting improved mechanical handling characteristics. EXAMPLE 4 Example 3 was repeated except that 0.5% by weight of the final camposition of quar gum was added. Again the addition of guar gum had only a marginal effect upon the green crushing strength but produced a significant improvement in green shatter strength, thereby imparting improved mechanical hardening characteristics.
8
Claims (15)
1. A process for the cold briquetting of fine coal comprising mixing fine coal with a binder to produce a water-containing briquetting mix and briquetting the mix, characterised by the presence in the briquetting mix of up to 2% by weight of the mix of a cement whereby the initial green strength of the resulting briquettes is improved.
2. A process according to claim 1, wherein the mixture is briquetted at an elevated temperature.
3. A process according to claim 2, wherein the mixture is briquetted at a temperature above 500C.
4. A process according to any preceding claim, wherein the binder ccmprises molasses, a sugar or a starch solution and an inorganic hardening agent.
5. A process according to any preceding claim, when the binder ccmprises molasses in an amount of fram 5 - 15% by weight of the mix together with a hardening agent selected from iron oxide (or iron ore), calcium carbonate (or limestone), calcium phosphate (or phosphate rock) and aluminium oxide (or bauxite) optionally together with an acid.
6. A process according to any preceding claim, wherein the cement is an ordinary Portland cement.
7. A process according to any preceding claim, wherein the cement is mixed with dry coal before addition of the binder.
8. A process according to any of claims 1 to 6, wherein the cement is mixed with the coal during or after addition of the binder.
9. A process according to any preceding claimr wherein the cement 9 is present in an amount of up to 0.5% by weight of the mix.
10. A process according to any preceding claim, wherein the briquetting mix further contains a gum.
11. A process according to claim 10, wherein the gum is present in 5 an amount of up to 1% by weight of the mix.
12. A process according to claim 10 or 11, wherein the gum is xanthan gum or guar gum.
13. A process according to any preceding claim, wherein the coal is a high rank non-caking coal.
14. A process according to claim 13,, wherein the coal is anthracite duff.
15. A process for the cold briquetting of fine coal substantially as hereinbefore described with reference to any of the Examples.
is Published 1989 at The Patent 0Ince, State House, 66171 High Holborn, London WC1R 4TP. Further copies maybe obtained from The Patent Offfee.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB878725252A GB8725252D0 (en) | 1987-10-28 | 1987-10-28 | Briquetting process |
Publications (1)
Publication Number | Publication Date |
---|---|
GB2211512A true GB2211512A (en) | 1989-07-05 |
Family
ID=10626040
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB878725252A Pending GB8725252D0 (en) | 1987-10-28 | 1987-10-28 | Briquetting process |
GB8823443A Withdrawn GB2211512A (en) | 1987-10-28 | 1988-10-06 | Briquetting process |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB878725252A Pending GB8725252D0 (en) | 1987-10-28 | 1987-10-28 | Briquetting process |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0314322A3 (en) |
CN (1) | CN1022845C (en) |
AU (1) | AU2370788A (en) |
GB (2) | GB8725252D0 (en) |
ZA (1) | ZA887733B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4212452A1 (en) * | 1992-04-14 | 1993-10-21 | Sophia Jacoba Gmbh | Cold briquetted coal |
CN110317651A (en) * | 2019-05-30 | 2019-10-11 | 太原科瑞康洁净能源有限公司 | The method for producing clean formed coke based on alumina transition state binder |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2723367B1 (en) * | 1994-08-03 | 1996-10-25 | Lafarge Fondu Int | BINDER FOR COLD AGGLOMERATION OF FINE FINES, AGGLOMERATOR OF SUCH PRODUCTS AND METHOD FOR MANUFACTURING SUCH AGGLOMERATES |
WO2004063315A1 (en) * | 2003-01-09 | 2004-07-29 | Brickett Technologies Limited | Handling of coal fines |
CN102618343A (en) * | 2012-04-10 | 2012-08-01 | 雷军 | Instant water coal briquette and molding method thereof |
CN103524090B (en) * | 2013-10-08 | 2015-08-05 | 黄金海 | A kind of method of construction waste water-permeable brick |
CN105992811A (en) * | 2013-12-26 | 2016-10-05 | 株式会社Posco | Briquettes, method for producing same, and apparatus for producing same |
CN105838469A (en) * | 2016-06-08 | 2016-08-10 | 北京神雾环境能源科技集团股份有限公司 | Composite adhesive for molding coal powder and method for preparing molded coal |
CN106906017A (en) * | 2017-03-21 | 2017-06-30 | 陕西科技大学 | A kind of briquette binder and its application method |
WO2021020958A1 (en) * | 2019-07-29 | 2021-02-04 | Робертс СТРАКИС | Binder for hard coal briquetting by cold pressing process |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB414364A (en) * | 1932-10-26 | 1934-07-26 | Arthur A Roberts | Improvements relating to the manufacture of fuel briquettes from carbonaceous material |
GB414361A (en) * | 1932-10-26 | 1934-07-26 | Arthur A Roberts | Improvements relating to the manufacture of fuel briquettes from carbonaceous material |
GB428982A (en) * | 1934-07-06 | 1935-05-22 | Charles James Lord | Improvements in fuel briquettes |
GB430233A (en) * | 1935-02-06 | 1935-06-14 | Arthur Fredrik Echberg | Improvements in and connected with coal bricks and like fuel products |
GB2079780A (en) * | 1979-12-06 | 1982-01-27 | British Gas Corp | Agglomeration of coal |
GB2086420A (en) * | 1980-10-28 | 1982-05-12 | Ervald Finn | Briquetting coal by vibration without use of binders |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR334983A (en) * | 1903-09-01 | 1904-01-07 | Gustave Quentin | Process for the manufacture of coal balls and briquettes |
FR762992A (en) * | 1933-10-27 | 1934-04-21 | Apparatus for producing radioactive water | |
GB716653A (en) * | 1952-04-25 | 1954-10-13 | Standard Oil Dev Co | Improvements in or relating to the briquetting of coal fines |
GB2181449B (en) * | 1985-10-05 | 1989-05-04 | Bobrite Limited | Fuel briquettes |
GB8606332D0 (en) * | 1986-03-14 | 1986-04-23 | Coal Industry Patents Ltd | Coal briquetting process |
GB8616214D0 (en) * | 1986-07-03 | 1986-08-13 | Shann P C | Fuels |
-
1987
- 1987-10-28 GB GB878725252A patent/GB8725252D0/en active Pending
-
1988
- 1988-10-06 EP EP88309301A patent/EP0314322A3/en not_active Withdrawn
- 1988-10-06 GB GB8823443A patent/GB2211512A/en not_active Withdrawn
- 1988-10-13 AU AU23707/88A patent/AU2370788A/en not_active Abandoned
- 1988-10-17 ZA ZA887733A patent/ZA887733B/en unknown
- 1988-10-27 CN CN88107460A patent/CN1022845C/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB414364A (en) * | 1932-10-26 | 1934-07-26 | Arthur A Roberts | Improvements relating to the manufacture of fuel briquettes from carbonaceous material |
GB414361A (en) * | 1932-10-26 | 1934-07-26 | Arthur A Roberts | Improvements relating to the manufacture of fuel briquettes from carbonaceous material |
GB428982A (en) * | 1934-07-06 | 1935-05-22 | Charles James Lord | Improvements in fuel briquettes |
GB430233A (en) * | 1935-02-06 | 1935-06-14 | Arthur Fredrik Echberg | Improvements in and connected with coal bricks and like fuel products |
GB2079780A (en) * | 1979-12-06 | 1982-01-27 | British Gas Corp | Agglomeration of coal |
GB2086420A (en) * | 1980-10-28 | 1982-05-12 | Ervald Finn | Briquetting coal by vibration without use of binders |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4212452A1 (en) * | 1992-04-14 | 1993-10-21 | Sophia Jacoba Gmbh | Cold briquetted coal |
CN110317651A (en) * | 2019-05-30 | 2019-10-11 | 太原科瑞康洁净能源有限公司 | The method for producing clean formed coke based on alumina transition state binder |
Also Published As
Publication number | Publication date |
---|---|
CN1042175A (en) | 1990-05-16 |
CN1022845C (en) | 1993-11-24 |
ZA887733B (en) | 1989-07-26 |
EP0314322A3 (en) | 1989-08-16 |
GB8725252D0 (en) | 1987-12-02 |
AU2370788A (en) | 1989-05-04 |
EP0314322A2 (en) | 1989-05-03 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |