Report on the nuisances arising from gasworks / Metropolitan Association of Medical Officers of Health, Trade Nuisances Committee.

  • Metropolitan Association of Medical Officers of Health (London, England). Trade Nuisances Committee.
Date:
1857
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Licence: Public Domain Mark

Credit: Report on the nuisances arising from gasworks / Metropolitan Association of Medical Officers of Health, Trade Nuisances Committee. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    effect of the oxide is to separate sulphuretted hydrogen, a black sulphurei of iron being formed. The oxide is changed at intervals, varying in different works from 36 hours to 10 days. When removed from the purifiers it is “ revivified ” by exposure to the action of the air, the oxygen of which decomposes the sulphuret, throws down the sulphur, and reconverts the iron into peroxide. It is then damped, and again used. The duration of the exposure necessary for revivification varies, with the age of the oxide and the length of time it has been in the purifier, from 24 hours to 14 days. It resumes each time its red colour. The process of revivification is capable of very frequent repetition. The same oxide may thus be in use for many months; in fact until the sulphur precipitated accumulates in such quantity as to prevent the revivification of the oxide. Dr. R D. Thomson has found the sulphur reach 45 per cent. f Cream of lime; “ wet lime.” The apparatus used for this mode of purification mostly resembles that described when the muriate of manganese was mentioned. In the Phoenix Works (Vauxhall),—a model of the wet lime process,-—the gas is made, by an arrangement of plates and bells within the purifier, to bubble three times through the wet lime contained in one purifier ; the lime being prevented from settling by agitation effected by machinery. When the cream of lime is saturated (viz., about once in twenty-four hours,) it is usually run off into pits, where the lime may settle ; the plastery matter which deposits being used for luting, sometimes alone, some- times when mixed, for the sake of an improved consistency, with refuse dry lime. The cream of lime separates carbonic acid, sulphuretted hydrogen, and ammonia. g. The “ dry lime,” or hydrate of lime, is exposed on screens in a box to the action of the gas, in the same manner as the oxide of iron. It serves to remove carbonic acid, sulphur, and cyanogen compounds; and, when other effectual means of separating ammonia have not preceded, becomes strongly charged with ammonia. When removed from the purifiers (usually every four or five days) it is commonly placed in a heap in the yard, and used for luting. There are various sources from which annoyance to a neighbourhood may arise in carrying on the manufacture of gas. Against some of them the Committee considers that remedies might readily be suggested. 1. Smoke. It has been remarked above that the amount of smoke from the furnaces is usually very insignificant. That which is here referred to proceeds from the openings at the roof of the retort-house, and at certain periods beclouds the atmosphere to some distance about them. The periods at which this nuisance is at its height are when the retorts are being charged, or the coke withdrawn. The evolution of smoke was noticed by the Committee to be less during the charging of the single than of the continuous retorts. The former are charged usually by a single scoop, and the cover is adapted and the process thus completed in a very few seconds, and before the coals can become sufficiently heated to part with much volatile matter. With the continuous retorts, on the other hand, not only is there a delay arising from the double charging at each end, but if one cover be adapted only a few seconds before the other a quantity of smoke commonly issues from the open extremity, and in the case of cannel gas a blast of ignited gas has been seen by the Committee to extend to the distance of several feet from the open mouth. The Committee suggests that much of this might be avoided if two scoops at each end were used instead of one, both being ready filled before the charging commenced, the mouth-pieces being immediately and simultaneously adapted. The withdrawal of the coke should be effected as quickly as possible, and no time should be lost in quenching it with water. But under the best arrangements a great deal of smoke is necessarily given off, which, with the steam produced by the quenching, should be prevented from becoming a nuisance. Probably a remedy might be found in the closure of the ordinary openings at the roof, and in place of them forming one or more communications, at the upper part of the retort-house, with the chimney or tall shaft which carries off the heated air and smoke from the furnaces. Should there be objections to this plan, doubtless gas-eng’ineers would readily discover an effectual means of overcoming its difficulties. 2. The use of the refuse lime from the 'purifiers in luting the mouth-pieces is another very obvious source of nuisance in most of the retort-houses. As the refuse lime contains sulphur and other noxious compounds, it gives off, when heated, very disagreeable and probably pernicious vapours. The Committee is of opinion that this practice should be discontinued, and that fresh lime, the coke ash luting formerly mentioned as in use at the Chartered Works, or some other equally unobjectionable material, should be employed. 3. Ammoniacal liquor and tar. In some works where the pits were uncovered an offensive odour was observed to proceed from this source. The proper remedy is that adopted in the majority, viz., to cover the pits, and to convey these products of condensation without exposure to the barges which are to carry them away. 4. Revivification of the oxide of iron. The offensiveness of this process depends upon the evolution of ammonia, which is favoured by a rise in temperature which the oxide undergoes during the process. The Committee observed that this nuisance is less in those works where effectual means of removing ammonia are employed prior to the passage of the gas to the oxide purifiers. Something also seems to depend upon the frequency with which the oxide is revivified. The oxide prepared by lime and sulphate of iron on removal from the purifiers contains also sulphate of ammonia and carbonate of lime, the reaction of which upon one another at the elevated temperature that accompanies the revivification produces further ammoniacal fumes with the