Desorption efficiency

“ If our flying-machines need a sort of ballast to reinforce their mechanical lifting apparatus, hydrogen is the best possible assistant. And the probable uses of oxygen are yet more numerous. So long as we still burn anything at all except a mixture of oxygen and hydrogen—and ultimately we shall have nothing else left to burn—oxygen is capable of multiplying the efficiency of all combustion. One of the greatest problems of our own day is the disposal of waste products of all sorts—the sources of inconvenience, disease and dirt. ”

“ The difference in temperature and increased hardness of the spring water, determine the class of water.
FILTRATION is the artificial method of clarification by mechanical and chemical means. By the mechanical system heavier impurities are held in suspense by percolation of water through carefully prepared beds of sand, gravel, coke, shells, and like substances.
The total area of the London filter beds in 1874 was 68 acres, and rate of filtration per hour in inches and depth of water, or head on beds, were:
The efficiency of filtration is inversely to rate of flow. ”

“ The matters in solution will partly, after removal out of the liquid, be retained by the absorbing powers of the soil in the pores, a process that is due to physical and chemical agencies.
Absorbing powers gradually ripen.
It is well known that land which is being treated with sewage for the first time does not purify sewage so well as land that has been under systematic treatment for some time, and this is probably due to the absorbing powers, which gradually ripen until they have reached their maximum of efficiency. ”

“ Waste recycling and reuse have become accepted practices in many industrial sectors. In some industrialized countries technologies to scrub sulphur and nitrogen compounds from smokestack gases made remarkable advances in a relatively short time. New combustion techniques simultaneous, raise combustion efficiency and reduce pollutant emissions. [13] Innovative products and process technologies are also currently under development that promise energy- and resource-efficient modes of production, reducing pollution and minimizing risks of health hazards and accidents. ”

“ It may be questioned whether a certain amount of segregation of the materials will make any practical difference in the efficiency of a filter. In all probability this depends on the degree of the segregation, the quantity of pollution in the water to be filtered, the rate of filtration, and the uniformity of methods followed in the operation, etc. For an applied water as excellent in quality as that of the Washington City Reservoir during favorable summer conditions, a considerable degree of segregation might exist without producing any diminution in efficiency. ”

“ After the proper production of the gas, we have still the processes of purification to consider, and how this operation can best be effected at the smallest cost, combined with efficiency and the least possible annoyance to residents in the immediate vicinity of gas works. I think all gas engineers are agreed that in ammoniacal liquor we have a useful and powerful purifying agent, although each one may have his own particular idea of how this can be most efficiently applied--some advocating scrubbers, others washers. But these are things which each one must determine for himself. ”

“ Sampler: Thermal sampling tube, 1⁄4” s.s. tube, multi-bed sorbents capable of trapping organic compounds in the C3-C16 range. Exact sampler configuration depends on thermal desorber system used. See Figure 1 for example. 2. Personal sampling pump, 0.01 to 0.05 L/min, with flexible tubing. 3. Shipping containers for thermal desorber sampling tubes. 4. Instrumentation: thermal desorption system, focusing capability, desorption temperature appropriate to sorbents in tube (~300 C) , and interfaced directly to a GC-MS system. 5. ”

“ Filter media may also be affected by humidity. Moisture may affect a filter’s collection efficiency. Very low humidities (#10% RH) may make some filters (e.g., cellulose ester) develop high charge levels, causing non-uniform deposits and repulsion of particles [9] . Water absorption by some filters (e.g., cellulose ester) can cause difficulty in obtaining tare weights for gravimetric analysis. Sampling flow rate*/ Face velocity
Breakthrough volume of a solid sorbent bed tends to be smaller at higher sampling flow rates, particularly for coated solid sorbents. ”

“ After all the moisture has been driven off from the coal, the distillation of hydrocarbons begins, and a considerable portion of them escapes unburned, owing to the deficiency of hot air, and to their being chilled by the relatively cool heating surfaces of the boiler. During all this time great volumes of smoke are escaping from the chimney, together with unburned hydrogen, hydrocarbons, and carbonic oxide, all fuel gases, while at the same time soot is being deposited on the heating surface, diminishing its efficiency in transmitting heat to the water. ”

“ The engineer who operates the pumps takes care of the filters, and no additional labor has been required. The entire cost of operation is thus represented by the additional coal required for the preliminary lift from the wells to the filters. The effluent is always free from iron.
The plant at Reading, [46] Mass., was installed by the Cumberland Manufacturing Company, and combines aeration, treatment with lime and sulphate of alumina and rapid filtration. The aeration is effected by pumping air through the water, after the water has received the lime. ”

“ Mere exposure to the air, even if accompanied by violent agitation, is comparatively powerless for the removal of polluting organic matter from water. Although, however, the flow of a river has thus but little effect in purifying the water by the oxidation of the dissolved organic matters, it has a most material influence in the removal by subsidence of a large proportion of the suspended impurities both organic and mineral, especially if the flow be sluggish in places. ”

“ Usually, after grinding, it is simply stirred up repeatedly with hot water and the aqueous extract is siphoned off. That such a crude method should be in vogue at the present time is very significant of [79] the ample margin of profit that must exist. By systematic extraction and filtration under pressure the washing may be effected with so little water that the solution is sufficiently concentrated to pay for evaporation by the heat of waste furnace gases, the recovered sodium sulphate serving to replace part of the raw material. ”

“ Concentration*
As the concentration of contaminant in air increases, breakthrough capacity (mg adsorbed) of a solid sorbent bed increases, but breakthrough volume (L of air sampled) decreases [10] . Particle Characteristics
Filter collection efficiency is a function of pore size [11] . Particles smaller than about 0.2 μm are collected primarily by diffusion, while particles larger than about 0.2 μm are collected primarily by impaction and interception. Most sampling filters are highly efficient ($95%) for all particle sizes, with the minimum efficiency in the 0.2 μm size range. ”

“ The whole question in this case is a different mechanical arrangement in our dwellings, not difficult to imagine or construct, separating fluids from solids—in short, a retort for a receptacle to which the application of gas or fuel in another form might be made at pleasure. The water-closet would become a fire-closet with chemical arrangements to fix the noxious gases. The chemical world is largely at work upon the process of deodorisation, and it will be accomplished. The chief error lies in trying to deodorise with a thousand-fold dilution. ”

“ Gas thus produced is intensely hot; and as usually it contains sulphur, dust, dirt, and other admixtures, their removal by water in a scrubber would involve a waste of about 30 per cent. of the fuel heat. This loss is much diminished by sending into the producer not only air but steam, to be decomposed into oxygen and hydrogen; the oxygen combines with carbon to form more carbon monoxide, while the hydrogen is the most valuable heating ingredient in the emitted stream of gases. Were only air sent through the producer, the outflowing gases would contain nitrogen to the extent of 65 per cent. ”

“ While our experiments certainly indicate a reduction in efficiency after washing so regular and persistent as to make it doubtful whether incomplete washing can be the cause of it, it may be questioned whether or not wasting the effluent would be necessary or desirable in actual operation. At any rate the results as given in this report are not materially influenced by this factor.
INFLUENCE OF AMOUNT OF SULPHATE OF ALUMINA ON BACTERIAL EFFICIENCY OF MECHANICAL FILTERS. The number of bacteria passing a mechanical filter is dependent principally upon the amount of sulphate of alumina used ”

“ Relatively more material is adsorbed out of dilute solutions than out of more concentrated ones. An increase of ten times in the concentration of the dissolved material results in only four times as much adsorption by the colloidal substance which [Pg 216] may be introduced into the two solutions. In this, adsorption differs from chemical action, as the latter is proportional to the concentration of the reacting material which is present in the solution. (b) Adsorption out of different liquids, by the same adsorbing body, is different in amount. It is usually greatest out of water. ”

“ The pressure drop of a filter can limit the sampling time, because of the load on the personal sampling pump. In addition, pressure drop increases with dust loading on the filter. Fine particles (#0.5 μm) will increase the pressure drop much faster than coarse particles ($10 μm) . Heavy loading ($ about 1 mg) may result in poor adhesion of collected particles to the filter surface. *NOTE: It is important to distinguish between equilibrium (saturation) adsorptive capacity and kinetic (breakthrough) adsorptive capacity of the solid sorbent. ”

“ When we see the process which is necessary in order to obtain pure gas, we begin to appreciate to what an extent the atmosphere is fouled when many of the products of distillation, which, as far as the production of gas is concerned, may be called impurities, are allowed to escape free without let or hindrance. In these days of strict sanitary inspection it seems strange that the air in the neighbourhood of gas-works is still allowed to become contaminated by the escape of impure compounds from the various portions of the gas-making apparatus. ”

“ Unpurified coal-gas thus contains sulphuretted hydrogen—the gas of rotten eggs—and bisulphide of carbon. A considerable part of the sulphuretted hydrogen is removed in the "condensers" and "scrubbers" by the action of water and ammonia. It has, however, been found that, if coal-gas is washed too much, its illuminating power is greatly impaired, and indeed all washing does some injury to it in this respect. To complete the removal of sulphuretted hydrogen, the washed coal-gas is passed through large boxes, containing either lime or oxide of iron, and which are termed purifiers. ”

“ This process is termed destructive distillation, and the property displayed by coal is common to all vegetable and animal substances; but only coal and petroleum have been used economically in the production of illuminating gas on an extensive scale. The distillation is the most important operation in the manufacture, but it is necessary to remove from the gas, before it is fit for burning, the condensible vapors, as tar, water, etc. ”

“ By filtration, water may be deprived of living beings and of all suspended impurities; but substances held in solution, cannot thus be separated. Ebullition destroys the vitality of both animals and vegetables; expels air, or carbonic acid, and causes the precipitation of carbonate of lime, but the water should be afterwards subjected to the process of filtration. Distillation, when properly conducted is the most effectual method of purifying water. ”

“ With either strategy, if two gauze wipes were included in the samples, then use 40 mL of desorption solution. If four gauze wipes were included in the samples, then use 80 mL of desorption solution. a. In strategy A, the volume of internal standard spiking solution is kept at a constant ratio of 2 μL per mL of desorption solution added. This enables larger samples to be desorbed without diminishing the area of the GC peak for the internal standard. ”

“ Desorption in toluene was adequate except as noted in 2 and 3 above. The use of toluene containing 10% acetone improved recoveries for all analytes to satisfactory levels. 5. The desorption characteristics of these compounds were not evaluated. General: a. The presence of acidic hydrogen or double bonded oxygen anywhere in the molecular structure greatly decreases solubility in non-polar solvents and increases the difficulty of desorption from polar surfaces and sorbents. ”

“ Where the pollution is less, so that the dissolved oxygen contained in the raw water is sufficient for the oxidation of the organic matters, continuous filtration will give substantially as good results as intermittent filtration, and in other respects it has important advantages. ”

“ The efficiency of the Linde process is small, but it is easily conducted and only requires plenty of cheap power. When we can work turbines or other engines at low temperatures, so as to effect cooling through the performance of external work, then the economy in the production of liquid air and hydrogen will be greatly increased. ”