OA16729A - Chemical binder coating payload in open top hopper cars, trucks, piles and similar storage/shipping containers. - Google Patents

Abstract

The invention is directed towards methods and compositions for treating piles of particulate materials to inhibit and prevent the loss of valuable fuel or mineral dust from being released from storage piles or open containers. The method involves applying to the pile a binder coating containing VAE and crude glycerin. The binder coating cures and hardens slowly so it is able to remain flexible while the pile or payload is still settling, jostling, being bumped, and otherwise moving around. This coating is especially effective for coal piles and also for piles within and /or being moved by open topped railroad cars. The coatings flexibility prevents the coating from becoming brittle and shattering. The coating has better performance than its ingredients do alone. The coating is effective both when it is flexible and after it cures. As a result the invention can both prevent unwanted dust pollution as well as save its users money by avoiding loss of blown away material.

Description

CHEMICAL B1NDER FOR COATING PAYLOAD IN OPEN TOP HOPPER CARS, TRUCKS, PILES, AND SIMILAR STORAGF./SHIPPING CONTAINERS

C'ross-Refcrence to Reiated Applications

Not Applicable.

Statement Regarding Federally Sponsored Research or Development

Not Applicable.

Background of the Invention

This invention relates to methods and compositions for containing particulate matter within open top réceptacles including but not limited to open top happer cars, trucks, piles, and similar storage and / or shipping containers. Treatîng a load of particulate material (and in particular coal) with a binding agent (sometimes referred to as a crusting agent) to encrust a surface and thereby retain valuable material as well as prevent the sprcading of dust from the particulate is known. Prior binding agents arc described among other places in US Patent

5,441,566. These binding agents include latexes, petroleum products, and pine tar resins. Other binding agents include phenolaldehyde resin mixed with a polyisocyanate in the presence of a catalyst (described in US Patent 5,244,473), alkaline phenolic resin (described in US Patent 5,089,540), and styrene in a hygroscopic solvent (methyl ethyl ketone), polyvinyl acetate and water (described US Patent 5,487,764). Additional dust suppressants are described in US Patents

5,181,957 and 5,747,104, 5,648,116, US Published Patent Application 2009/0189] 13 Λ1, and

Published PCT Applications 02/12574 AI, 2010/110805 Al and 2009/023652 Al.

Unfortunatcly many of these binders cause the particulate inaterial to retain large amounts of water which cnn lead to dimînislted value and eiîeciiveness. In the context of coal, increased water content results in decreased B PU content and increased Itkclîhood of spontaneous combustion from water induccd oxidation of the coal. Furthermore the binders tend to form brittle coatings which tend to shatter and dissipate as the particulate material serties and shi fis due to thc effects of transit and storage. Problems due to the brittleness of the binder coatings become exaeerbated when the material is stored in environments where the température fluctuâtes above and below freezing. This is because freezing and melting moisture further shifts the materials further shattering the binder coating.

Prior art binding materials also hâve a number of winter handling problems that can render application dlfficult and potentielly ineffective. This is because such products often hâve a freezing point near that of water and once frozen, they no longer work. Even worse these prior art binder coatings after being frozen are not recoverable even after they hâve thawed or me lied if they hâve been frozen. This greatly limits the conditions in which they can be used and applied.

Thus it is clear thaï thcre is clear utility in novel methods and compositions for binding the top of particulate matériels stored or shipped in open top containers. The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is Prior Art with respect to this invention, unless specificoily designated as such. In addition, this section should not be construed to mean tJial a search has been made or that no other pertinent information as defined in 37 CPR § 1.56(a) exists.

Brief Summary of the Invention

At least one embodiment ofthe invention is directed towards a method of inhibtting the release of dust from a pile of particulate material. The method comprises the step of applying to the exposed surface of the pile a binder composition. The binder composition comprises VAE and crude glycerin in a ratio of between 90:10 and 10:90.

The composition may further comprise water but the composition does not pass significant amounts of water to the pile. The cure rate of the composition may be siowed to allow settling of the pile. The pile may be within an open topped container. The pile may be within an open topped railroad car which is moving at least a part of the time. The particulate material may 5 bc coal.

Detailed Description of the Invention

The following définitions are provided to détermine how terms used in this application, and in particular how the daims, are to bc construed. The organisation of the définitions is for convenience only and is not intended to limît any ofthe définitions to any particular category.

“Crude giyccrin” means a by-product dérivative from a transestérification reaction involving triglycérides including transestérification réactions involving biodiesel manufacturing proccsscs, in which the by-product comprises glycerin and at least one component selected from the list consisting of: fatty acids, esters, sait methanol, tocopherol, sterol, mono-glycerîdes, diglycerides, and tri-glycerides.

“Particulate material” means ” a material that has a tendency to form dust particles when handled, processed, or contacted, which includes but is not limited to coal, dîrt, wood chips, agricuitural productif, fruits, fertilizers, ores, minerai ores, fine materials, sand, gravek soil, fertilizers, or other dust generating material, and any combination thereof.

“PVA” means polyvinyl acetate polymer.

“Mong” means non glycerol organic material and typically consiste of soaps, free fatty acids, and other impurities.

“VAE” means vinyl acetate ethylene co-polytner. In at least one embodiment the repeating units of VAE arc selected from onc of formula 1, 11, 111, IV, and any combination thereof wherein:

	............. 1 o li -0-0 _______________________i		Il o _____
	F -c	H O l x z*» M		H 0 1 1
		o		1 hJ

U—	1 H'
		1

Formula (I)

Formula (II)

₃Hp‘

I

H O I I “C-O

t

H— Q—H I

H—C—H

H i

~C^C

I I

H O

O=C _ ^HsC

Formula (III) ch₂—

		Γ H Ί
CHj™	******	| -0^2“” C~“	—
	n	—— I **· 0	m

Formula (IV)

t β

wherein n is the number of cross lînking units, m is the number of first chain units, and o is the number of second chain units, either, some, or ali of n, m, and o can be i or inore, although m and o will frequently be 2 or 3 or 4 or more, either or both of the first and second chain units can be left side end (terminal) units of a polymer chain and/or right side end (terminal) units of a polymer chain. VAE can also comprise co-polymers containing additional cross linking units and can comprise additional polymer chains.

in the event that the above définitions or a description stated elsewhere in this application is inconsistcnt with a meaning (explicit or implicit) which is commonly used, in a dictionary, or stated in a source incorporated by référencé into this application, the application and the claim ternis in particular are understood to be construed according to the définition or description in this application, and not according to the common définition, diclionary définition, or the définition that was incorporated by référencé. In light of the above, in the event that a term can only be understood ifit is construed by a dictionary, if the term is defined by the Kirk-Othmer Encyclopedia of Chemical Technology, 5th Edition, (2005), (Published by Wiley, John & Sons, Inc.) this définition shall control how the term is to be defined in the claims.

In at least one embodiment the surface of a pile of particulate matter is treated with a binder to prevent the loss of material and the release of dust from the pile. The binder is a composition comprising a VAE copolymer and crude glycerin The crude glycerin is derived from a transestérification reaction involving triglycérides.

Biodiesel îs typically made through a chemical process called transestérification in which vegetable oil or animal fats are converted to fatty acid alkyl esters and crude glycerin byproduct. Fatty acids and fatty acid alkyl esters can be produced from oils and fats by basecatalyzed transestérification ofthe oil, direct acid-catalyzed estérification ofthe oil and conversion of the oil to fatty acids and subséquent estérification to biodiésel.

The majority of fally acid alkyl esters are produced by the base-catalyzed method. In general, any base may be used as the catalyst used for transestérification of the oil to produce biodiesel, however sodium hydroxide or potassium hydroxide are used in most commercial processcs.

Suitable examples of crude glycerin and its manufacture can bc found in among other places in US Patent Application 12/246,975. In the biodiesel manufacturing process, the oils and fats can be filtered and preprocessed to remove water and contaminants. If free fatty acids are présent, they can be removed or tran s formed into biodiesel using spécial pretreatment technologies, such as acid catalyzed estérification, The pretreated oils and fats can then be mixed with an alcohol and a catalyst (e.g. base). The base used for the reaction is typically sodium hydroxide or potassium hydroxide, being dissolved in the alcohol used (typically éthanol or methanol) to form the corresponding alkoxîde, with standard agitation or mixing. It should bc appreciated that any suitable base can be used. The alkoxidc may then bc charged into a closed reaction vessel and the oils and fats are added. The system can then be closed, and held at about 71 degrees C (160 degrees F) for a period of about 1 to 8 hours, although some systems recommend that the reactions take place at room température.

Once the reactions are complété the oil molécules (e.g. triglycérides) are hydrolyzed and two major products are produced: 1) a crude fatty acid alkyl esters phase (i.e. biodiesel phase) and 2) a crude glycerin phase. Typically, tlie crude fatty acid alkyl ester phase forms a layer on top ofthe denser crude glycerin phase. Because the crude glycerin phase is denser than the biodiesel phase, the two can be gravity separated. For example, the crude glycerin phase can be simply drawn off the bottom of a settling vessel. In some cases, a centrifuge may be employed to speed the séparation ofthe two phases.

The crude glycerin phase typically consiste of a mixture of glycerin, methyl esters, methanol, mong and inorganic salts and water. Methyl esters are typically présent in an amount of about 0.01 to about 5 percent by weight.

In at least one embodiment, methanol can be présent in the crude glycerin in an amount greater than about 5 weight percent to about 30 weight percent. In at least one embodiment, the crude glycerin comprises about 30 to about 95 weight percent of glycerin.

VAE is a copolymer in which multiple vinyl acetate polymers contain ethylene side branches which form cross linkages and connect the polymers to each other forming copolymer networks.

In at least one embodiment the binder composition comprises between 90:10 and to 10:90 of VAE copolymer to crude glycerin by mass. In a( least onc embodiment the composition further comprises water. fn at least one embodiment the composition comprises water and the crude glycerin both prevents the freezing of the water and prevents its évaporation thereby increasing the lifespan and flexibilîty of the resulting coating. In at least one embodiment the binder coating contains water but does not transfer water to the coal bound by it.

ln at least one embodiment the composition is applied according to any one of the methods or apparatuses of US 5,441,566. In at least one embodiment the binder îs applied to a pile within an open top container and forms a binder coating which prevents the substantial release of dust from the pile and the érosion of the pile by the release of such dust. In at least. one embodiment the pile is within an open top railroad car and the binder coating prevents dust release and érosion while the car is travelling al railroad shipping speeds (for example >0 mph 250 mph).

The components of the coating composition may be mixed immediately before addition to the particuiate material or may b© pre-mixed or some components may be pre-mixed and other components may be mixed immediately before addition to the particuiate material. The material may be applied in liquid form by a spray boom having one or more spray heads. In at least one embodiment the binder composition is applied to the material to be coated by at least one ofthe methods disclosed in US Patent 5,622,561.

In at least one embodiment the particulate material is drying slurry. Often in industrial applications a particulate material is or bccomes heavily intermixed with water or another liquid and forms slurry, This slurry needs to hâve some or all of die liquid removed before a subséquent process can be performed on the material. Whilc drying (whether by a dewaterlng technique or if left out to evaporate away the liquid by heat, sunlight, or the like) some or all ofthe slurry dries out and can generale dust émissions. The composition can bc upplied lo 10 a surface ofthe slurry to control dust émissions. The composition can be applied to the material when it is slurry, partially dry, complctcly dry, and any combination thereof. In at least one embodiment the slurry is Red Mud lrom a Bauxite mining and/or refining operation. In al least one embodiment the dust that is controlled comprises Sodium Carbonate particles. In at least one embodiment the composition is applied to slurry that Is left to dry tn a retaining pond or other sort 15 of pond, basin, pool, or straining, drying, or filtering réceptacle.

In at least one embodiment the composition is applied as the pile is being formed. When a particulate material is poured or dumped to form a pile, some of the material billows away from the pile in form of airborne dust. This can occur for ex ample when material is loaded into a rail car, dump truck, storage facility, silo, or ship’s hold. The composition can be applied 20 to the material before and/or as it is poured or dumped into a pile. In at least one embodiment the material passes along a convoyer belt before it is poured or dumped and the composition is applied to the material as it travels along lhe belt. In at least one embodiment the composition functions as a tackifïer which holds together the material in the form of larger elumps that are less likely to launch as airborne dust.

The inventive composition is quite effective and displays a number of unexpected and bénéficiai results. Prior art coating formulations such as PVA form a rigid glue shell or crust. This rigid glue shell contains particulate matter when intact, but suffers from a number of constraints. Prior art shells tend to be brittle and shatter when subjected to significant movement or displacement. With particulate matériel, particularly coal, and especially coal containcd in a rapidly moving, jostling, and bumping railcar, tlie particulate material shifts as it serties into a more compact arrangement and this movement tends to shatter the brittle prior art shells. Raîlcars also tend to be inipacted rather hard when being shunted in transfer stations which further increases the Iikelihood of shattering prior art binding coatings.

Tlie unique chemistry of the composition however allows the binding coating of the invention to avoid shattering during settling and while moving at highspeeds in a railroad car or when undergoing bumps or impacts. Without limitation to theory and in particular the scope of the daims, it is bclîeved that lhe ethyiene cross linkages between the polymer strands function as flexible hinges between tlie poJymcrs. This allows the polymer strands to move, bend, and

J5 flex relative to each other more than prior art coatings allow, while at the same time providing an as good or better “glue” effect to the pile. The crude glycerïn provides a syncrgistic effect which enhances the flexibility of the copolymer without impairing its structural strength.

In at Ieast one embodiment, the cure rate (the amount of time needed before the glue like coating hardens) of the composition is an amount of time greater than it takes for the 20 pile of particulate material to scttlc into a consistent arrangement. Thus when treated, the pile is always licld in place, first by a more flexible coating and later by aharder cured coating. l he composition has a longer cure rate than either VAE or other prior art binder coatings have by themselves.

In at Ieast onc embodiment the unique eutectic point of the crude glycerïn

enhances the performance of the composition. Crude glycerin is known to hâve a relatively high frcczing point (similar to water) when il is nearly pure (more than 90%) or very dilate (less than 10%). However when it is eut with. VAE, the frcczing point of the blended material is reduced as is the fieezing point of any water in solution with the blended material. As a resuit, when crude glycerin is combined with VAE in the above mentioned ratios (both with and without water), the overall composition is more résistant to fieezing and therefore becomes far less britlle (and cures more slowly) than a composition containing a higher or lower ratio of crude glycerin or other prior art binding coatings would otherwise hâve. Moreover as previously stated, many coating formulations become ruincd once they become frozen and will not form adéquate coatings even after thawed out again. Because the composition is less pronc to frcczing, it can bc applied under conditions in which prior art coatings would become frozen and are therefore unusable.

EXAMPLES

The foregoing may bc better understood by reference to the following exemples, which are presented for purposcs of illustration and are not intended to limit the scope of the invention.

Tailings slurry from a minerais processing operation was used in a study lo assess tlie inhibition ofdust génération under various Lreatmcnt régimes.

The treatments used included:

· Water - as used by many minerais processing operations to control dust formation in holding dams and/or tailings ponds.

Comparative example #1; A commercially available dust control product comprised of a styrene-acrylate copolymer.

Comparative example Ü2: A commercially available dust control product comprised of a concentrated glycerin solution in water.

• Product A — a binder comprising a 50:50 mixture of VAE copolymer and crude glycerin.

A sample of tailings slurry was collected from a minerais processing faeility and sub-samples were placed Into plastic tubs (dimensions -33 x 33 x 28cm) which were lincd with filter cloth and had a sériés of holes in the base to allow free drainage of any runoff liquid. Samples were stored in a greenhouse and allowed to dry for one week. Treatments as outlincd in table 1 were then applied as 1% solutions to the surface ofthe dried tailings over u 10 week period. Each application used 500ml of 1% solution applied evenly to the surface of the dried tailings using a pump sprayer. Tests were completed using duplicate samples for each treatment régime.

Aflcr lhe 10 weeks of drytng and treatment the consolidated surface crust of each tailings sample was carefully removed and the underside brushed gently back into the tub to recover any dust présent. A vacuum attachment which covered the bulk of tire sample area was then gently pressed on the dried surface and the sample was vacuumed for 2 minutes. The collected dust (separate coarsc and fine fractions from 2 filtration Systems inbuilt in the vacuum cleanei) was weighed.

Table 1

Product	Application régime	Total Dust Collected (kg/m1) (Average of duplicate samples)
Water	Weekly	1.11 0.88
Water	'ï'wicc weekly
Comparative example #1	Weekly	0.19
Comparative exemple #1	Twice weekly	0.11
Comparative example #2	Weekly	0.92
Comparative example #2	Twice weekly	1.10
Product A	Weekly	0.03
Product A	Twice weekly	0.02

¹³

A fier the ) 0 weeks of drying and treatment the consolidated surface crust of each tailings sample was carcfully removed and lhe undersidc brushed gently back into the tub to recovcr any dust présent. A vacuum attachment which covered tlie bulk of the sample area was then gently pressed on llie dried surface and the sample was vacuutned for 2 minutes. Tlie collected dust (separate coarse and fine fractions from 2 filtration Systems inbuilt in the vacuum cleaner) was weighed.

The vacuum attachment also had 4 side inlets that were closed in the first dust collection. For a second collection air was fed air at 50 psi into the four inlets (generating a ‘mini cyclone’ environment) while the attachment was again pressed on the mud surface and the surfaces re-vacuumed for a further 2 min (Collection 2).

Total dust collected was recorded in kg/n? based on the weight of dust collected and the surface area of the vacuum attachment used to cover the surface where dust was collected.

The results in table 1 indicale lhe superior and surprising dust control properties of Product A when compared both to the two separate conventional, commercially available dust control treatrnenls, as well as water as a dust control measure.

While this invention may bc embodied in many different forms, there described in detail herein spécifie preferred embodiments ofthe invention. The présent disclosure is an exemplification of tlie principes of the invention and is not intended to litnit the invention to the particular embodiments illustrated. Ail patents, patent applications, scientific papers, and any other referenced materials mentioned herein are incorporatcd by référença in their entirety. Furthermore, the invention encompasses any possible combination of sonie or ail ofthe various embodiments described herein and incorporated herein.

The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in tliis art. Al! these alternatives and variations are intended to be included within the scope ofthe daims where the term comprising means including, but not limited to. Those familiar with the art may rccognïze other équivalents to the spécifie embodiments described herein which équivalents are also intended to be encompassed by the daims.

AU ranges and parameters disclosed herein arc understood to encompass any and ail subranges subsuincd therein, and every number between the endpoints. For example, a stalcd range of “1 to 10” should be considered to include any and ail subranges between (and inclusive 10 of) the minimum value of l and the maximum value of 10; that is, ail subranges beginning with a minimum value of 1 or more, (e.g. 1 to 6.1), and ending with a maximum value of 10 or less, (e.g. 2.3 to 9,4,3 to 8,4 to 7), and finally to each number 1,2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range.

This complétés the description ofthe preferred and altemate embodiments ofthe invention. Those skilled in the art may recognize other équivalents to the spécifie embodiment described herein which équivalents are intended to be encompassed by the daims attached hereto.

Claims (10)

1. Claims

   What is claimed is;

   1. Λ method of inhibiting the release of dust from a pile of particulate material, the method comprising the step of applying to the exposed surface of tlie pile a binder composition, the

   5 binder composition comprising VAE and crude glycerin in a ratio of between 90:10 and 10:90.
2. 2. Tlie method of claim 1 wherein the composition further comprises water but does not pass signifteant amounts of water to the pile.
3. 3. The methodof claim 1 wherein the cure rate of the composition is slowed to allow settling of the pile.

   10
4. 4. The method of claim 1 wherein the pile is within an open topped container.
5. 5. The method of claim 1 wherein the pile is within an open topped railroad car and the railroad car moves at least a part of the time.
6. 6. The method of claim l wherein tlie particulate material is coal.
7. 7. l he method of claim 1 wherein the particulate material is slurry.

   15
8. 8. The method of claim 1 wherein lhe particulate material is applied as the pile is being formed by a dumping process.
9. 9. The method of claim 1 wherein the dust would resuit from sodium carbonate being released by the pile.
10. 10. The method of claim 1 wherein the particulate material is Red Klud,

    20 11. The method of claim 1 wherein the pile is within a ship’s hold.