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Southern Dust Control XP1000 uses in Coal Storage Capping for Dust Control, auto combustion suppression and moisture barrier . And XD1000 For Coal dust suppression
Long standing problems of wind generated dust from coal storage piles, loss of fines from coal rail wagons and water consumption necessary to prevent auto combustion in transport and storage are reduced by applying a new proprietary product which forms a surface crust. Preliminary tests of this concept are presented.






Worldwide, coal production and use has been plagued by dual problems of dust and spontaneous combustion. Dust represents both a loss of product and a contaminant, or worse, a health threat.
Attempts made to address these problems usually involve water. Products designed to retain or extract water from the air, primarily ?salts?, frequently have negative side effects on the environment and are also individually limited by ambient humidity. Conversely, direct addition of water has three drawbacks:
1. It is a repetitive expensive operation to perform;
2. An electric generation inefficiency is inherent because added water must be boiled off before energy production is gained from combustion and
3. Water consumed from this use is evaporated into the atmosphere and is therefore not available as a liquid to serve other needs of society.
Research into alternative environmentally benign mechanisms to control dust from other sources has resulted in development and refinement of new products. Successful use of these products to address soil based dust, asbestos and aluminum dross lead to the question, ?Are they workable with coal??
STATEMENT OF PROBLEMS:
A/ It was not documented whether coal dust particles could be modified by recently developed dust suppressants.
B/ It was not documented whether coal dust particles could be bonded with newly developed adhesives.
C/ No information was available on how coal piles surface treated with adhesives would shed water.
D/ No information was available on how coal piles surface treated with adhesives would withstand wind action.
E/ No information was available on how coal piles surface treated with adhesives would retain water.
F/ No information was assembled on combustion byproducts from coal treated with the new family of products.
BENCH TESTS OF CONCEPT:
A representative sample of local Pennsylvania (USA) bituminous coal was obtained from the unit-train loading tipple at Lady Jane Mine in Penfield, Elk County.
A/ Reaction coal dust with Product ?DS? :
Setup and Procedures:
Fines, 2.38 mm (#8 screen), were sieved from the sample and divided into two equal piles. Pile #1 was carefully placed in the bottom of a clear glass vessel, an air hose was initially embedded within the coal fines. The air pressure was released until all fines were lost from its path and then the hose was waved over the coal fines to maximize disturbance. A digital camera movie recorded the reaction. The height of the dust cloud was recorded and marked with a colored line on the vessel and shown in the ?after? photo.
Pile #2 was treated with 9 grams of product ?DS?. Pile #2 was then subjected to the identical regimen. Observations were made on dispersal and pictures were taken. Measurements, in seconds of hang-time, were made and recorded, see Table A-1 and ?A? photo series.
To examine resistance to water absorption and recovery another sample of coal was treated with Product DS and then covered with water and allowed to soak for 14 hours. Observations were made and a picture recorded.
RESULTS AND INTERPRETATION
Table A-1 Enumeration of contrasting data between the control coal dust and the coal dust treated with product DS.
Photos A-1, The experimental setup: A pressurized air supply is discharged into equal amounts of coal.
Photo A-2, The 5 cm height of the observed dust cloud from the control sample is marked at the top of the vessel, note purple line.
Photo A-3, The 1 cm height of the observed dust cloud from the DX1000 treated sample is marked near the bottom of the vessel, note purple line.
Photo A-4, The contrast of residual dust electrostatically clinging to the glass walls is shown on the dust towel used to wipe one line from bottom to top. Photo A-5, After soaking 14 hours in water, the additional sample of DX treated coal fines show no mixing of the treated particles. Clear water can be observed in the near foreground. Not shown is the sample after all water was evaporated off; it behaved exactly as before soaking.
CONCLUSIONS:
Based on these observations and measurements, it is concluded that Pennsylvania bituminous coal fines do respond to this new product. It appears the particles are penetrated and weighed down because there is no indication that water wash-off or penetration occurs.
Company representatives report that it is very long lived and remains effective as long as the treated particles remain on site. Re-treatment is needed only when new dust is added to the site, and then only the amount needed to treat the additional material must be added.
B/ Test Bonding of Product PX1000 with bituminous coal
A six-millimeter deep layer of coal, as prepared for rail freight at the Lady Jane rail tipple, was added to a 20 mm diameter table plate and sprayed to near saturation with a 3:1 (water to PX) mixture and allowed to cure. An equal amount of untreated coal was placed in a second plate. One side of each plates edge lip was removed so there would be no impediment to the material flowing off the plate.
Each plate was then held in front of a plumb level, which was placed to show true vertical, and progressively tipped to a 90-degree or true vertical angle. Observations were made. The discharge angle at which the control plate was emptied was marked with a black line on the background, photos and videos were taken.
In order to better observe the mechanism by which this surface bonding occurs a further procedure was conducted. A 13mm X 20mm clear plastic tub was filled to a depth of approximately 8mm with coal, as prepared for rail freight. The surface was sprayed with a 3:1 (water to PX) mixture using two passes in perpendicular directions. The container was shaken to cause limited movement of coal lumps, which were on the surface and preventing penetration, and an additional spray pass was made. The tub was set aside for 12 hours to cure.
Observations, and measurements were made. The coal surface was then probed with an index finger to ascertain whether there was an observable difference in the two surfaces and observations were recorded.
OBSERVATIONS AND MEASUREMENTS:
See Photo # B-1, B-2. Movie B-1 shows the control plate spilling material soon after movement from level and being completely empty at the angle shown by the black line on Photo B-2.
Clearly bonding had occurred because an observable skin had formed from the near surface material. This skin could be moved or bent slightly without breaking.
A scalpel was used to carefully cut a 30mm X 50mm patch of skin and lift it from the bed material. The removed skin measured between 1 & 3 millimeters thick. It was flexible enough to swing and strong enough to hold a 13mm diameter lump adhered to one end.
The clear plastic tub provided a visual, but not photographable, cross-section of the mechanism. Before curing, Product PX is a milky Black liquid so its penetration could be observed.
Nearly all the liquid pooled and adhered to itself and particles on the surface, forming the reported maximum 3mm thick skin. Where coal lumps created voids against the sidewall some down flow occurred. That deeper penetration did not create any significant binding of the coarse lumps.
CONCLUSIONS:
Based on these observations and measurements it was definitely concluded that a true binding of coal particles occurred. Furthermore, that binding was not brittle or extremely fragile because of its flexibility.
Any proposed use in outdoor conditions requires considerations of reactions to wind and moisture. Therefore these additional small-scale tests were conducted.
C/ Test of Water Repulsion or Shedding:
Next, the treated plate of material from bench test B was weighed and then subject to simulated rainfall. Using a Pagasus Model 609-285 Drenching 25mm showerhead operating at city water pressure of approximately 40 kgf/cm2 allowed to from one meter above the sample. Water temperature was approximately 30 degrees Celsius to approximate warm summer rains.
The plate was held at an approximate 60-degree steep angle and directly in the main flow. The drenching nozzle produces a flow remarkably like real rain; it was trapped in a bucket of a diameter equal to the flow pattern to measure an approximation of the amount of rain it would represent.
Flow was continued until 1 cm of water was measured in the trap bucket. A digital moving recording was made of the test. Time was recorded. There was no control for this test because all the untreated coal had slid off its plate in the earlier test B.
OBERVATIONS AND MEASUREMENTS:
The coal skin shed water and resisted failure even at this unnaturally steep angle. It was observed before and made obvious by this water flow that full saturation of the material had not occurred.
That is, as can be seen in the video, if available, a minor amount of un-bonded fines were trapped under the skin and they flushed out. That occurred quickly; at the end of the test, water running under and over this coal skin was clear. Before and after weight comparisons indicate loss of 16gms. After weight was after evaporation of free water.
A stopwatch was used to time how long it took to accumulate 5cm of water in the trap bucket. It took 27 seconds or the equivalent of 150cm of rain per hour.
Photograph C-1, The drenching shower nozzle is shown in perspective to the plate size. The sprinkler pattern definitely covered the whole plate throughout the test.
Photograph C-2, The plate was held one meter below the muzzle to establish a uniform point of reference. That metric can be replicated if it desired to conduct further tests on full saturation of thicker skins or other coals.
Photograph C-3, Washed clean but still intact
D/ Test Wind Resistance:
Two test boxes of the same approximate configuration and proportions as a coal wagon were obtained. They were filled with coal, shaken slightly to approximate settling in initial transport and weighed.
Test box # 1 was then sprayed with a 1:1 mixture of Product PX at the rate of 1 kiloliter/4000 m 2 and allowed to dry overnight at approximately 20 degrees Celsius.
Both containers were then securely strapped to a van roof top using care to position them equally in relation to airflow. An ink line was traced as accurately as possible along the rim line of coal in each box. Photographs were taken.
The van was driven in stop and go conditions for 8 kilometers (5 miles) at speeds not exceeding 64 (k/h) kilometers or 40 miles per hour. A second line was traced along the rim line of the control sample and photographs were taken.
Next, the van was driven at a rather steady 80 k/h (50 mph) for 24 kilometers. There were no significant winds or air disturbance other the vehicles movement and whatever turbulence may have been generated from very occasional traffic. A dashed line was traced along the rim line of the control sample and photographs taken.
Although rail wagons usually do not exceed 64 k/h and although all visible fine material was already missing from the control sample, the van was driven an additional 120 kilometers at speeds between 105 and 120 k/h. Photographs were taken.
The sample boxes were sealed in plastic bags to prevent moisture loss that would affect weights and then reweighed at a later time. The results were recorded and are reflected Table D-1.
The samples were frozen to determine whether that would cause failure of the skin. Observations were made that both while frozen and after thawing the skin remained pliable and as intact as before freezing.
Note loss should be considered a function of surface area and would probably remain constant regardless of depth of containers. Loss appeared to occur at a steady rate until the surface was stabilized by a layer of coarse material of sufficient size to resist the wind; all fines that could be withdrawn from between the coarse material was lost.
Photograph D-1, The control test box with the black line showing the initial level of the coal. After only 8 kilometers at 64 k/h, exposed on a van roof, the material loss was noticeable.
Photograph D-2, The difference between the dotted line and the solid line shows the amount of fines lost after 24 kilometers at 80 k/h. Virtually all surface fines were gone at this point.
Photograph D-3, After 12- kilometer at speeds up to 120k/h all available fines have been sucked from among the larger lumps and the larger lumps have been reshuffled by the wind to cover the dotted line.
Not shown is the PX treated test box. It was virtually unchanged from the beginning. There were a few minor cracks torn in the skin after the 80k/h segment and the .02% weight loss shown in Table D-1 reflects the fines drawn out of these racks.
F/ Test of Water Retention in Coal Piles:
No tests of water retention in coal piles have been made. It is suggested that insertion of continuously reading moisture probes could be inserted at various depths in a coal pile and readings made of any differences between a control and a pile treated with Product PX to form a surface skin.
Observations have been made of soil and stone aggregates, which were treated and a moisture layer clearly forms beneath the skin, much like you can observe under a flexible sheet of clear plastic.
F/ Comments on formation of combustion byproducts:
It is both impractical and undesirable to have to perform any preparatory work on the coal before it is sent to combustion. Therefore it needs to be known that any material used to treat, even a small portion of the coal, not generate combustion byproduct that are environmentally harmful.
No specific tests have been conducted however the chemistry is known and that eventuality does not appear to be a problem.
PROOF OF CONCEPT
Conceptually, coal wagon surfaces and storage pile surfaces could be sprayed with this colorless, low odor water-soluble product causing them to develop a surface skin, which would retain desired moisture and resist erosion from wind and rain. A discussion is called for on whether the losses of fine coal and pile moisture, which may be lessened by a protective layer of these products, is significant to merit further testing.
Observers concluded on the basis of these bench tests that discussions among coal handling operator experts should be invited. If there is a need for products of this nature more detailed studies and field trials could be easily undertaken.
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