EP0165350B1 - Process for producing a high concentration coal-water slurry - Google Patents

Process for producing a high concentration coal-water slurry Download PDF

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Publication number
EP0165350B1
EP0165350B1 EP84304234A EP84304234A EP0165350B1 EP 0165350 B1 EP0165350 B1 EP 0165350B1 EP 84304234 A EP84304234 A EP 84304234A EP 84304234 A EP84304234 A EP 84304234A EP 0165350 B1 EP0165350 B1 EP 0165350B1
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EP
European Patent Office
Prior art keywords
coal
slurry
weight
coal particles
particle diameter
Prior art date
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Expired
Application number
EP84304234A
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German (de)
English (en)
French (fr)
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EP0165350A1 (en
Inventor
Hirofumi C/O Kure Research Laboratory Kikkawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Power Ltd
Original Assignee
Babcock Hitachi KK
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Filing date
Publication date
Priority to JP58078352A priority Critical patent/JPS59204688A/ja
Application filed by Babcock Hitachi KK filed Critical Babcock Hitachi KK
Priority to EP84304234A priority patent/EP0165350B1/en
Priority to DE8484304234T priority patent/DE3476082D1/de
Publication of EP0165350A1 publication Critical patent/EP0165350A1/en
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Publication of EP0165350B1 publication Critical patent/EP0165350B1/en
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    • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
    • C10L1/00—Liquid carbonaceous fuels
    • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
    • C10L1/326—Coal-water suspensions

Definitions

  • This invention relates to a coal-water slurry, and more particularly it relates to a process for producing a coal-water slurry having a good stability, a high coal concentration and a low viscosity with minimal settlings.
  • CWM in the form of a mixture of coal with water
  • CWM abbreviation of Coal-Water Mixtures
  • CWM when CWM is practically used, a problem of storage is also raised.
  • CWM When CWM is stored in a usual tank, it is necessary for it to have a superior stability, but since CWM consists of coal particles and water, it is preferred to reduce their particle diameter, in order to inhibit coal particles from settling as much as possible. However, there is a tendency that when the particle diameter is reduced, the viscosity increases.
  • coal particles are not completely spherical, and also the method of measuring the particle diameter of coal particles are various as follows: a method by means of sieves, a settling method represented by the "Andreasen Pipette", a method of analyzing the particle shapes by way of photographs of SEM (Scanning Electron Microscope) to calculate their representative diameter, etc.
  • the definition of the particle diameter also varies depending on the measurement methods. This causes errors in adjusting the particle diameter distribution, and it becomes difficult to produce a CWM having a high coal concentration, a low viscosity and a good stability.
  • EP-A-0130849 discloses a process for producing a coal-water slurry having a low viscosity and a good stability, even in a high coal concentration, the process comprising feeding coal to a wet mill and grinding it therein, the coal which is fed to the wet mill being divided in a multi-stage manner.
  • the present invention aims to provide a process for producing a coal-water slurry having a high coal concentration, a low viscosity and a good stability.
  • a process for producing a coal-water slurry having coal particles dispersed in water comprises causing the slurry to have a composition of coal particles, so that when the coal particles are divided into 8 fractions (F 1 , F 2 , - - - and F B ), each having a particle diameter range listed below, ((from D L /4 to D L ), (from Dd42 to less than Dd4), - - - (from D L /4 7 to 0), wherein D L represents the maximum particle diameter of the coal particles), then the proportions by weight of the coal particles contained in the respective fractions, relative to the total weight of the coal particles contained in the slurry fall within the following ranges of numerical values: characterised in that at least one kind of anionic dispersant selected from the group consisting of naphthalenesulfonic acid, orthophosphoric acid, polyphosphoric acids represented by H n+2 P n O 2n+1 (n?21 or H n P n O 2n (n ⁇ 3), tarta
  • Coal is ground in wet or dry manner by means of a mill and a part of the resulting particles is taken to measure their particle diameter distribution.
  • the weight proportion of finely divided particles had a great influence upon the viscosity and the stability relative to the setting of the slurry.
  • the particles were divided into the following 8 fractions (each a constituent part as a group), and the respective fractions were each sieved by a sieve most adequate thereto (e.g. sieve according to JIS standards or millipore filter having the particle diameter well adjusted) to measure the weight of the fraction.
  • D L represents the maximum particle diameter of particles.
  • F 1 to F a represent symbols of the respective fractions.
  • particles were divided into 8 fractions for measurement, but the number of fractions is not always limited to 8, but practically it may be from 5 to 15 unless the distribution of the particle sizes changes.
  • More than one kind of coal or coal slurry were mixed so that the constituent proportions by weight of F 1 to F 8 might have a certain value, respectively, and if necessary, water was added for adjusting the water content, to study their viscosities.
  • the maximum particle diameter D L is too large, the amount of unburned matter at the time of combustion increases, while if it is too small, the slurry viscosity increases; hence the maximum particle diameter D L was made from 44 to 420 pm.
  • Figure 1 shows a chart illustrating the relationship between the particle diameter and the cumulative sieve pass weight proportion in the case where three kinds of slurries (No. 1 to No. 3) were prepared from coal A (bituminous coal, ash content 9.5%). There are shown cumulative particle diameter distributions in the case of a coal concentration of 70% and 1000 mPas (cP) or less. In this case, the maximum particle diameter D L is 297 ⁇ m and only distributions of particle sizes of 1 pm or larger are shown.
  • equations (1) and (2) as those indicating a particle diameter distribution mode of coal particles contained in a slurry exhibiting a low viscosity at a high coal concentration: wherein q represents an index.
  • This equation (3) corresponds to Andreasen's equation which has been known as a particle diameter distribution equation giving the closest packing for powder of a continuous particle size system.
  • Andreasen's equation is a distribution equation in the case where particles having an infinitesimal particle diameter were presumed, but the equation cannot be, as it is, applied to a practical coal-water slurry. In contrast the present inventors confirmed that the equation (1) and (2) correspond well to practical distributions.
  • particles were divided into the following 15 fractions (dotted lines in Figure 2 indicate the case of the equation (2) and solid lines therein indicate the case of the equation (1)):
  • coal-water slurry of the present invention is preferably composed so that diameter distribution of coal particles having particle diameters in the range of from 1,000 ⁇ m to 0.005 pm substantially satisfies the following equation and the following ranges of numeral values:
  • the slurry is preferably composed so that coal particles of 1 pm or less can be present in an amount of from 5 to 46% by weight and those of 0.05 um or less can be present in an amount of 0.5% or more, more preferably 1% or more.
  • the coal-water slurry has a coal content of 60 to 80% by weight and a viscosity of 5,000 mPas (cP) or less, in terms of numerical values obtained when an inner cylinder-rotation type viscometer is rotated at a shear rate of 90 sec -1 for 5 minutes.
  • a coal-water slurry when produced by the process of the present invention includes at least one kind of anionic dispersant selected from the group consisting of naphthalenesulfonic acid, orthophosphoric acid, polyphosphoric acids represented by H n+2 P n O 2n+1 (n ⁇ 2) or H n P n O 2n (n ⁇ 3), tartaric acid, oxalic acid, citric acid, ethylenediamine tetraacetate, ligninsulfonic acid, salts or condensates of the foregoing, tannins including quebracho-tannin and metal salts of carboxymethylcellulose, as a dispersant for coal particles in an amount of 3% by weight, or less, preferably 1.5% or less, based on the weight of the coal, and/or at least one kind of pH-adjustor selected from the group consisting of sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate may be added to the slurry as a pH-adjustor for rendering the
  • a condensate of sodium naphthalinesulfonate as dispersant was added to the slurry to observe the relationship between its amounts added and the slurry viscosities. The results are shown in Figure 5. In this case, the addition amounts are values based on the coal weight, and sodium hydroxide was added as pH adjustor in an amount of 0.1% based on the coal weight.
  • Example 3 With coal B (bituminous coal, ash content 13.6%), the same slurry as in Example 3 was prepared, followed by varying the amount of sodium hydroxide added, in a fixed amount of 0.5% of a condensate of sodium naphthalenesulfonate being added, to adjust the pH of slurry to thereby study the influence of pH upon slurry viscosity. The results are shown in Figure 6. Up to pH 8, the higher the pH, the lower the slurry viscosity, and at higher pHs, the viscosity is almost unchanged. Taking into consideration the amount of sodium hydroxide consumed and corrosion of material, a pH of from 7 to 9 is preferred.
  • the amount of sodium hydroxide added, necessary for adjusting the pH from 7 to 9, is from 0 to 1.0% based on the weight of coal.
  • the results are shown in Figure 7.
  • the penetration time of the ordinate axis refers to a ratio of the penetration time in 30 days after preparation of slurry to that just after the preparation
  • the amount of ultrafine particles added refers to a proportion thereof based on the total weight of coal after the addition.
  • the stability is best in an amount of the ultrafine particles added of 3%, and it is seen that particles of 0.05 ⁇ m or less contributed to the slurry stability.
  • the amount of the dispersant added is optimum in a range of from 0.1 to 1.5% and it is preferred to add a pH adjustor so as to give a pH of from 7 to 9.

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Liquid Carbonaceous Fuels (AREA)
EP84304234A 1983-05-06 1984-06-22 Process for producing a high concentration coal-water slurry Expired EP0165350B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP58078352A JPS59204688A (ja) 1983-05-06 1983-05-06 高濃度石炭−水スラリの製造方法
EP84304234A EP0165350B1 (en) 1983-05-06 1984-06-22 Process for producing a high concentration coal-water slurry
DE8484304234T DE3476082D1 (en) 1984-06-22 1984-06-22 Process for producing a high concentration coal-water slurry

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP58078352A JPS59204688A (ja) 1983-05-06 1983-05-06 高濃度石炭−水スラリの製造方法
EP84304234A EP0165350B1 (en) 1983-05-06 1984-06-22 Process for producing a high concentration coal-water slurry

Publications (2)

Publication Number Publication Date
EP0165350A1 EP0165350A1 (en) 1985-12-27
EP0165350B1 true EP0165350B1 (en) 1989-01-11

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Family Applications (1)

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EP84304234A Expired EP0165350B1 (en) 1983-05-06 1984-06-22 Process for producing a high concentration coal-water slurry

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EP (1) EP0165350B1 (cg-RX-API-DMAC7.html)
JP (1) JPS59204688A (cg-RX-API-DMAC7.html)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4810259A (en) * 1985-09-19 1989-03-07 Oxce Fuel Company Method to minimize viscosity and improve stability of coal-water fuels
JPS62265392A (ja) * 1986-05-12 1987-11-18 Kubota Ltd 石炭水スラリ−

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130849A1 (en) * 1983-07-05 1985-01-09 Babcock-Hitachi Kabushiki Kaisha Process for producing a high concentration coal-water slurry

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3762887A (en) * 1970-12-14 1973-10-02 Consolidation Coal Co Fuel composition
DE2836440A1 (de) * 1978-08-19 1980-03-06 Ruhrchemie Ag Verfahren zur herstellung einer kohle- wasser-suspension, die zum einsatz in eine kohlevergasung unter erhoehtem druck geeignet ist
US4282006A (en) * 1978-11-02 1981-08-04 Alfred University Research Foundation Inc. Coal-water slurry and method for its preparation
IT1211049B (it) * 1981-05-21 1989-09-29 Snam Progetti Sospensione acquosa di carbone.
JPS5838791A (ja) * 1981-08-31 1983-03-07 Ube Ind Ltd 高濃度石炭・水スラリ−の製造方法
JPS5896690A (ja) * 1981-12-03 1983-06-08 Electric Power Dev Co Ltd 石炭の高濃度スラリ−の製造方法
JPS5896691A (ja) * 1981-12-03 1983-06-08 Electric Power Dev Co Ltd 石炭の高濃度スラリ−の製造方法
JPS58213096A (ja) * 1982-06-07 1983-12-10 Hitachi Ltd 石炭・水スラリの製造方法
JPS58222191A (ja) * 1982-06-18 1983-12-23 Ube Ind Ltd 固体燃料−水スラリの製法
JPS5915486A (ja) * 1982-07-16 1984-01-26 Ube Ind Ltd 固体燃料−水スラリの製造方法
JPS5915488A (ja) * 1982-07-20 1984-01-26 Kawasaki Steel Corp 微粉炭の高濃度水スラリ−化方法
JPS5958093A (ja) * 1982-09-29 1984-04-03 Babcock Hitachi Kk 石炭スラリ−の調整方法
JPS5958092A (ja) * 1982-09-29 1984-04-03 Babcock Hitachi Kk 石炭スラリの製造法
JPS59157183A (ja) * 1983-02-25 1984-09-06 Babcock Hitachi Kk 石炭−水スラリ

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130849A1 (en) * 1983-07-05 1985-01-09 Babcock-Hitachi Kabushiki Kaisha Process for producing a high concentration coal-water slurry

Also Published As

Publication number Publication date
JPS59204688A (ja) 1984-11-20
JPH0344118B2 (cg-RX-API-DMAC7.html) 1991-07-04
EP0165350A1 (en) 1985-12-27

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