US3356470A - Dustless carbonized fuel - Google Patents

Description

United .States Patent {Marillieff ,ietf-,assigner te Cliffs DOW Chemi lCqrnpany, MarquettgMich., a corporation of Miehig- Fied NOV 18, 1964, Ser. No. 412,213 'Y rciims. (ci. 4 4-10) No Drawing.

This invention relates te earbenized fuels that have been treated to redue or eliminate the tendency to form dus! and/er .te Seil the 'hands er any material Coming in Contact therewith. Char-seal, either `-im naturel lump Yferm er in the form of molded briquets, is widely used for heating and cooking, especially as fuel for barbeque grills and the like. In such use, `a serious objection to ordinary charcoal :is .its tendency to produce a iine dust the box or bag in which it is sold and .the ease with whichit produces black smudges on the hands or on any material with which it comes in contact.

To overcome the tendency to dust and smudge, many treatments have been proposed but none has been commercially successful. Thus, it has been proposed to coat the charcoal'with paraffin wax (Patent No. 2,842,431) or Witll synthetic polymers such as Methocel (Patentn'No.

2,822,251). Such processes are too costly, they adversely affect the ignition and burning qualities of the product or they produce objectionable smoke or odor in burning.

In the case of briquets they moreover require predried briquets, they impede the later drying of the briquets or they form only a -surface film, which, once broken, exposes an essentially unprotected charcoal surface.

The present invention provides a simple and'inexpensive treatment for charcoal which avoids or reduces the above difficulties and provides clean, essentially dustless and non-smudging charcoal. For purposes of simplicity and ease of understanding, the invention is described below with specific reference to charcoal. The invention can also be used with carbonized solid fuels made from other Wood-like materials, such as fruit pits, nut shells, corncobs, peat, lignite, and the like, or briquets containing selected chars of mineral origin suitable for barbeque fuels, or briquets made` from a mixture of these carbonized materials, and the invention claimed herein applies to such carbonized materials.

According to the invention, charcoal and the like, in the natural lump form or as briquets, is rendered substantially dustless and non-smudging by the application of an aqueous sugar solution followed by drying.

The sugar may be any of the common pentoses, hexoses, disaccharides or oligosaccharides. These include sucrose', maltose, glucose, xylose, and the like, either in pure form or as crude industrial products, such as cane sugar molasses, bee sugar molasses, Wood sugar molasses, citrus molasses, invert sugar syrups, corn syrup, sugar cane syrup, and the like. Because of effectiveness, low cost and ready availability, the preferred sugar sources are sugar cane molasses, beet sugar molasses and Wood sugar molasses. A particularly suitable species of the latter is described by H. D. Turner, Forest Products Journal, July 1964, pp. 282-284.

The optimum concentration of the sugar solution varies somewhat with the nature and composition of the fuel to be treated, particularly its porosity and affinity for aqueous uids. The most economical treatment involves wetting the surface of the fuel while substantially limiting penetration to not more than l-3 mm. Deeper penetration is wasteful since it adds little or no benefit. On the other hand, thorough surface impregnation and some slight penetration are necessary to assure an essentially dustless product which retains its cleanliness after the 3,356,470 Patented Dec. 5A, 1967 Tice `llersal tumbling and abrasion ineidentalte the PreeeSS- ing, packaging, 'shipping and handling of the product. lt `is a particularly vdesirable .and valuable eharaeteristie 0f the ,fuels treated by vthe process .ef :thenyention that they are essentiallydustless not only .as Preudeed in the ,faetory but also .after normal handling in Commerce and that, v,even after abrasion has caused considerable accumula- .tion of relatively tine particles, these particlesare themselves largely clean Iand nonfdusting, being of a granular nature rather than the fine dust 'that is characteristic of untreated fuels.

Another fact/or that influences the optimum .concentran-,tion of the sugar solution used in practicing the invention is the temperature at which it is .applied to the fuel.Y At elevated temperatures the viscosity ofthe solution is reduced and a more concentrated solutioncan be used than at lower temperatures and still achieve adequate penetration of the fuel` -without lengthening the contact 7these factors is critical, .highly satisfactory results are obtainable with sugar solutions of l0-60% `concentration (all percentages are Vvby weight unless otherwise specified). With reference to molasses, dilution of ordinary black- .strap molasses in the proportion of l part molasses to .0.2 to .4 parts of water is convenient, a ratio of about l1:1 being preferred. Though undiluted molasses can be used if desired, this is wasteful of molasses and care should be taken to avoid excessive pick-up, since this may result in a sticky surface on the fuel.

The sugar solution can be applied vto the fuel in any Way. The simplest and preferred method comprises dipping the fuel into the solution. A quick dip is usually adequate, though longer immersion produces good results also, although resulting in somewhat deeper penetration. Suitable times are from one second to live minutes or more. The temperature at which the sugar solution is applied to the fuel is not critical and can be varied widely. Ordinarily the temperature is one of convenience. Thus, When both the solution and the fuel are at ambient temperature, it is not necessary to change this by either heating or cooling the materials. If the fuel is already hot, it may be treated while hot. In a dipping process this will warm the sugar solution, thus reducing its viscosity and accelerating both penetration and drainage of excess solution. With some solutions, particularly black-strap molasses, elevated temperatures sometimes promote foaming and are thus objectionable, though operable, in a dipping process. When the sugar is applied by spraying, foam is no problem, of course. In general, the solution can be applied at any temperature at which it is liquid, the most convenient temperature being about 20-80 C.

Since the present invention is particularly directed to the dust-proofing of solid fuels used in cooking, and more particularly -to such fuels used in broiling meats, and since charcoal is by far the most Widely used such fuel, the treatment of charcoal and especially charcoal briquets, constitutes a preferred application of the present invention. In the production of charcoal briquets (as well as briquets of carbonized corncobs, lignite and the like) the char is crushed to granular particles of up .to about 6 mesh size. These are mixed with a binder, commonly Ia starchy material, in sufficient water to make a plastic mass that is then molded into briquets. As formed, the briquets (hereinafter referred to as green briquets) contain about 30% moisture and are at a temperature of about 50 to 60 C. Most conveniently, and as a special feature of this invention, they may be immediately f absorption.

coated with the'sugar solution and then dried in the usual way. Alternatively, the `finished, vdriedbriquets can be and complete wetting of the surfaces by the solution,

or, on the other hand, in excessive penetration and In the optimum treatment of charcoal briquets, the

concentration of the solution and the time and temperature of treatment are selected so as to provide a complete surface coating or impregnation with slight penetration,

of the order of 1-3 mm. This usually entails a pick-up of the coating material of about 3-6%, based on dry .weight of briquet and coating material.'

' The practice of the invention is illustrated by the following example.

Hardwood charcoal pillow-shaped briquets having a dry weight of about 20-22 g. were taken directly from the briquet molding machine, at a temperature of about 460 C. and a moisture content of about 30%. They were momentarily immersed in a coating solution consisting of a mixture of equal volumes of black-strap molasses (67% solids) and water. The coated briquets were then dried in the usual way by an air current at 130 C. There was very little drainage from the briquets when taken `from the solution and no tendency of the briquets to ,clump together, either before, during or after the drying stage. No significant increase in drying time was required Resultsl substantially similarjto those described above were -obtained when lump charcoal was similarly coated.

'Moreover, 'similar `good results were obtained with bri- 'quets' containing other binders or made from other materials, such as carbonized corncobs or lignite, or with other sugar solutions instead of molasses as set forth hereinbefore. Thus, the invention is broadly applicable to any charred carbonaceous fuel that is suitable for use as `a barbeque fuel.

I claim:

1. The method of producing essentially non-dusting, non-smudging briquets of carbonized fuel comprising 1) contacting green briquets of the carbonized fuel with an aqueous solution of a sugar containing l0 to by weight of sugar, thus to impregnate at least the surface layer of the briquets, and then (2) drying the briquets at yan elevated temperature and for a time suflcient to render the briquets substantially non-tacky and non-smudging.

2. The method of claim 1 wherein t-he sugar is provided in the forrnof molasses. Y 3. The method of claim 2 wherein the fuel is essentially charcoal.

4. The method of claim 2 wherein the solution of molasses contains lll-60% by weight of molasses solids.

5. The method of claim 4 wherein the briquets Aare `dipped into the molasses solution.

6. Briquets made by the process of claim 1.

7. Briquets made by the process of claim 4.

References Cited UNITED STATES PATENTS 6/ 1881 Great Britain.

-DANIEL E. WYMAN, Primary Examiner., C. F. DEES, Assistant Examiner. i

Claims (2)

1. THE METHOD OF PRODUCING ESSENTIALLY NON-DUSTING, NON-SMUDGING BRIQUETS OF CARBONIZED FUEL COMPRISING (1) CONTACTING GREEN BRIQUETS OF CARBONIZED FUEL WITH AN AQUEOUS SOLUTION OF A SUGAR CONTAINING 10 TO 60% BY WEIGHT OF SUGAR, THUS TO IMPREGNATE AT LEAST THE SURFACE LAYER OF THE BRIQUETS, AND THEN (2) DRYING THE BRIQUETS AT AN ELEVATED TEMPERATURE AND FOR A TIME SUFFICIENT TO RENDER THE BRIQUETS SUBSTANTIALLY NON-TACKY AND NON-SMUDGING.

6. BRIQUETS MADE BY THE PROCESS OF CLAIM 1.