FORMED CARBON FUEL BRIQUETS

• US 3,762,886 A
• Filed: 06/14/1971
• Issued: 10/02/1973
• Est. Priority Date: 06/14/1971
• Status: Expired due to Term

• Current Assignee: Great Lakes Carbon Corporation (Sgl Carbon Se)
• Original Assignee: Alfred A. Triska
• Inventors: Triska, Alfred A.
• Primary Examiner(s): Dees, C. F.
• Application Number:
  US05/152,605
• Time in Patent Office: 841 Days
• Field of Search: 44/1E,1R,1G,1R,16A 75/42
• US Class Current: 44/559
• CPC Class Codes: C04B 14/022 Carbon
• CPC Class Codes: C04B 18/021 agglomerated by a mineral binder, e.g. cement
• CPC Class Codes: C10L 5/02 Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin peat briquettes C10F
• CPC Class Codes: C10L 5/22 Methods of applying the binder to the other compounding ingredients; Apparatus therefor

Abstract

Formed fuel briquets of reduced reactivity are prepared with the use of a binder contributing little, if any, green strength. The fuel is suitable for such purposes as industrial and metallurgical applications and for domestic heating. Briquets possessing high green strength, and high shatter and compressive strength in the cured state, are produced even while employing a rapid compacting operation, such as roll briquetting. Carbon aggregate, of controlled particle sizing, and preferably of a specified type, is an essential ingredient employed in the making of the formed fuel. The use of a hydraulic setting cement binder, such as Portland cement, which reduces the reactivity of the formed briquets, is also an integral part of the process, as are also a compacting step and a curing step, and the employment of closely controlled conditions particularly with respect to the use of water in each of these steps.

Claims

2. A process according to claim 1 wherein the forming step is carried out employing a pressing time of no more than 2 seconds.

3. A process according to claim 2 wherein the forming step is carried out by means of a roll briquetting press.

4. A process according to claim 1 wherein the formed fuel from step b is permitted to set for a limited period before the addition of water in the curing step.

5. A process according to claim 3 wherein the mixture charged to the roll briquetting press contains at least 4 parts of water and wherein the mixture also contains at least 50 percent of the water required for the water sorption characteristics of the carbon aggregate.

6. A process according to claim 1 wherein the addition of water in the curing step is carried out within 30 minutes after the forming step.

7. A process according to claim 3 wherein the pressing force employed in the forming step is between about 1.4 and about 6.0 metric tons per centimeter of face contact.

8. A process according to claim 7 wherein the pressing force employed in the forming step is between about 2.0 and about 5.0 metric tons per centimeter of face contact.

9. A process according to claim 1 wherein the carbon aggregate possesses inadequate porosity to provide adequate hydrophilic attraction by means of absorption to produce a firm mass of the desired green strength and wherein an effective amount of an agent selected from the group consisting of hydrated lime, bentonite, sodium silicate, non-swelling clays, molasses, tar, starch and sugar to increase the green strength of the formed fuel is added to the mixture before it is formed.

10. A process according to claim 1 wherein forming step b is carried out at a substantially ambient forming temperature.

11. A formed fuel prepared by the process of claim 1.

12. A process for the production of a formed and cured carbonaceous fuel which comprises the following steps:

a. Preparing a mixture of at least three ingredients comprising 100 parts by weight of carbon aggregate, about 3 to about 15 parts by weight of hydraulic setting cement binder per 100 parts of carbon aggregate, and about 3 to about 14 parts by weight of water per 100 parts of carbon aggregate, the parts of water being inclusive of any water derived from one or more of the ingredients making up said mixture;

b. forming the fuel by compacting its ingredients, while simultaneously fracturing some of the carbon aggregate, utilizing sufficient water in the forming step to produce a firm mass having a green compressive strength of at least 15 pounds but less water than is necessary to fully satisfy the water sorption of the carbon aggregate and the hydraulic setting of the cement, a pressing force of at least 1.4 metric ton per centimeter of face contact in case of roll briquetting, or the equivalent of at least about 0.18 metric ton per square centimeter in case of other methods of compacting also being employed in this forming step; and

c. curing the formed mixture by adding, within 120 minutes of completion of the forming step, sufficient water to satisfy water sorption of the carbon aggregate and also to permit the hydraulic setting of the cement, thereby producing a strong briquet;

said carbon aggregate being selected from the group consisting of delayed coker petroleum coke, fluid coker petroleum coke, pitch coke, anthracite, charcoal, bituminous coal and mixtures thereof;

the carbon aggregate after the forming step b also having an average particle size distribution such that when subjected to a screen analysis in which the screens are arranged so that the maximum size openings of the top screen in the screens employed is in the range of 3 to 6 millimeters, and the screen with the smallest size openings possesses openings of no less than 0.074 millimeter, and in which each successive screen after the top screen has openings one-half the size of the preceding screen, substantially all of the aggregate or 95 to 100 parts would pass through the screen having the maximum size openings and substantially equal amounts of about 13 parts by weight of the aggregate, varying by no more than about 4 parts, would be retained on each successive screen having openings one-half the size of the immediately preceding screen.

13. A process according to claim 12 wherein the forming step is carried out employing a pressing time of no more than 2 seconds.

14. A process according to claim 13 wherein the forming step is carried out by means of a roll briquetting press.

15. A process according to claim 12 wherein the formed fuel from step b is permitted to set for a limited period before the addition of water in the curing step.

16. A process according to claim 14 wherein the mixture charged to the roll briquetting press contains at least 4 parts of water and wherein the mixture also contains at least 50 percent of the water required for the water sorption characteristics of the carbon aggregate.

17. A process according to claim 12 wherein the addition of water in the curing step is carried out within 30 minutes after the forming step.

18. A process according to claim 14 wherein the pressing force employed in the forming step is between about 1.4 and about 6.0 metric tons per centimeter of face contact.

19. A process according to claim 18 wherein the pressing force employed in the forming step is between about 2.0 and about 5.0 metric tons per centimeter of face contact.

20. A process according to claim 12 wherein the carbon aggregate possesses inadequate porosity to provide adequate hydrophilic attraction by means of adsorption to produce a firm mass of the desired green strength and wherein an effective amount of an agent selected from the group consisting of hydrated lime, bentonite, sodium silicate, non-swelling clays, molasses, tar, starch and sugar to increase the green strength of the formed fuel is added to the mixture before it is formed.

21. A process according to claim 12 wherein forming step b is carried out at a substantially ambient forming temperature.

22. A process according to claim 12 wherein the average volatile matter content of the carbon aggregate is between about 4 percent and about 23 percent.

23. A process according to claim 22 wherein the carbon aggregate employed is delayed coker raw petroleum coke.

24. A process according to claim 22 wherein the carbon aggregate employed is fluid coker raw petroleum coke.

25. A process according to claim 12 wherein the carbon aggregate employed is calcined petroleum coke.

26. A process according to claim 12 wherein the carbon aggregate employed consists of a mixture of calcined petroleum coke and raw petroleum coke.

27. A process according to claim 12 wherein the carbon aggregate employed is charcoal.

28. A process according to claim 12 wherein the carbon aggregate employed consists of a mixture of anthracite and petroleum coke.

29. A process according to claim 12 wherein the carbon aggregate employed consists of a mixture of charcoal and petroleum coke.

30. A process according to claim 12 wherein the carbon aggregate employed consists of a mixture of petroleum coke and bituminous coal.

31. A process according to claim 12 wherein the carbon aggregate employed is bituminous coal or partially devolatilized bituminous coal or a mixture of these materials.

32. A formed fuel prepared by the proCess of claim 12.