Debris accumulation

Corrosion and mineral debris can form in condensate lines from a variety of means, and it is not uncommon for the resultant debris accumulated over many years to slough off and return to the boiler when operating conditions change. The result is often a thick boiler-bottom sludge that settles out in the water space or baked-on sludge, which mars efficient combustion and water tube heat transfer. 

Double-sided brush scrubbing followed by a spin-rinse-dry step dominates the industry. An example of a double-sided brush scrubber is shown schematically in Fig. 16. The rollers keep the wafer positioned and rotating while the brushes dean debris from both the front and back sides of the wafer. The cleaning solution is delivered through the bristles themselves. Typically, the bristles are porous so that fresh solution can be delivered directly to the wafer and minimal amounts of debris accumulate on the brush. Increasing the down force increases the particle removal efficiency up... 

Pericoronitis- It is the inflammation of soft tissues surrounding the crown of a partially erupted tooth and most commonly, a wisdom tooth. It generally occurs when bacterial plaque and food debris accumulate beneath the flap of gum covering the partially erupted tooth. It is characterized by inflammation, often complicated by trauma from the opposing tooth, leads to swelling of the flap, tenderness, pain and a bad taste due to pus oozing from beneath the flap. 

To provide channels for the removal of polishing debris and heat from the pad surface so as to reduce the possibility of scratch and generation of other defects due to the debris accumulation on the pad surface and to avoid rapid chemical reaction at localized high temperature regions due to frictional and chemical reaction heat ... 

The other wastewater produced as a result of regeneration is the backwash and rinse waters. As soon as the bed is exhausted, it must be backwashed to remove debris accumulated during the service cycle. In addition, after regeneration, the bed should be rinsed to remove any residual regenerant. Backwash and rinse water reqnirements should be determined by experiment on an actual exchanger bed to be nsed in design. 

The slits in the distribution header are designed to be essentially self-cleaning, and the accumulation of insolubles and precipitates does not constitute as serious a problem as it does in a downflow saturator. Cleaning frequency of the distribution header will depend on the usage and amount debris accumulated in the saturator. 

Oil residuals are the dominating sensory pollution source in new ducts. The sensory assessments showed a clear correlation between the total mass of oil residuals (average surface density times surface area) and the PAP (Fig. 7). Emissions from dust/debris accumulated in the ducts during construction (mostly inorganic substances) seem to be less important. No simple correlation was observed between the amount of accumulated dust and odour emissions however, the organic dust accumulated during the operation period may produce more severe odour emissions. When dust had accumulated on the inner surface of the ducts, the relative humidity of the air in the ducts had an effect. On the other hand, the relative humidity had virtually no effect on the odour emissions of oil residuals. 

The chemical changes which accompany photo-oxidation apparently predisposes the polymer to attack by micro-organisms. Previously, we reported that the physical changes which accompany severe photo-oxidation provide the perfect environment for debris accumulation to support the active growth of microorganisms ( 5). 

Considerable thought preceded selection of the direction of travel (up or down) of the fiber and the direction of flow of the gas reactants. It was judged best to have the fiber and reactants move in the same direction (upwards) for the following reasons. Foremost was the goal of keeping reactants out of the spool enclosures. The most critical enclosure is that on the end (bottom) at which the reagents are introduced since the gas pressure in the reaction chamber is greatest at this end. Also, the inlet end (bottom) stays eleaner than the exit where broken fibers and exhaust debris accumulate. 

Meanwhile, I also needed to work out a method of securing the dam plate to the inside of the culvert. I wanted it to be easy to remove the culvert dam to release debris accumulated behind it. And—if the plastic dam plate was broken (by big rocks tumbling through the culvert), I would need to replace it with an improved design. Either way, since... 

FIGURE 1.3 Coal seam discontinuities (a) recent erosion, (b) preglacial erosion, and (c) and (d) stream beds at the time of debris accumulation. 

The rate of plant debris accumulation required to produce a coal seam must be greater than the rate of decay. Once a thick layer of plant debris is formed, it must be buried by sediments such as mud or sand. These are typically washed into the swamp by a flooding river where the increasing weight of the mud and/or sand material compresses the plant debris and aids in its transformation into coal. 

Plant debris accumulates very slowly accumulating 10 ft of plant debris will take decades, if not centuries, and 50 ft of plant debris required to produce a 5 ft thick coal seam would require... 

Evidence for metallic debris accumulating in distant organs has also been confirmed by Langkamer et al [12] who identified wide spread dissemination of particulate wear debris from hip prosthesis to lymph nodes, fiver, and spleen. He reported increases above normal levels in these organs of 30 fold for aluminum, chromium, and iron in the lymph node, and 10 fold in the spleen and fiver. 

Materials of construction for ancillary systems are commonly carbon steel, fiberglass-reinforced plastic (FRP), epoxy-or phenolic-lined, stainless steel, and concrete. Many times waste transfer lines will change from a product contact material (near the process equipment) to carbon steel, stainless steel, or polyethylene (near the ancillary equipment). Vent tines are particularly troublesome and require special attention. Smooth surfaces (noncorrugated) with proper sloping to avoid areas for condensation and debris accumulation are essential to minimize corrosion. Smooth and sloping surfaces are cJso needed to aid in cleaning between campaigns. 

Under high-velocity process conditions, tubular element and wire loop probes may require velocity shields for protection. However, velocity shields are prone to debris accumulation with attendant spurious results from the probe and their use should be limited accordingly. 

S. Aging As plant aging, line inside flow area may change. In some case, it maybe fouled or debris accumulated and cause the flow area reduced. If this is expected, a larger line should be chosen or line cleanup device should be provided. On the other hand, some line may be corraded and needs to he replaced. 

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