A Visit to the Forth Bank Chemical Works, 1866

A Visit to the Forth Bank Chemical Works

The Forth Bank Works are situated in the lower part or outskirts of the ancient royal burgh of Stirling, on one of the tongues of land formed by the many links or windings of the river Forth, as it courses along through the beautiful carse of Stirling. The hills all around the carse were, at the time of our visit, covered with their winter mantle of virgin purity. As seen from the top of Cambuskeneth Tower, close by, the surrounding scenery has a beauty which contrasts most forcibly with the sludgy condition of the ground within the Forth Bank Works.

Regardless, however, of the footing underneath, we depart on our tour of inspection, Mr Shand, the while, apologising for it stating that the anxiety of the firm to meet the enormous demands of the departing winter left them no time to pay much attention to anything else. We begin at the beginning, and naturally inquire how the works are situated with respect to the means of transit for the crude material arriving at the works, and the finished products sent from them. We very soon find that the river Forth is the highway whose powers Messrs Shand & Company call into requisition. The river forms one of the boundaries of the seven acres of ground on which the works are located, and is deep enough, at the company's wharf, for lighters and coasting vessels to load or discharge their cargoes with the utmost facility. One vessel is constantly employed by the firm in taking a cargo of oil to London, at least once every month, besides large quantities which are sent steamers. In the busy season the amount shipped at Leith and Grangemouth varies from 400 to 800 barrels weekly. The proximity of the works to the railway station is likewise in favour of the firm, as there is thus ample facility for railway communication with the whole of Scotland.

Crude oil is brought from the works of Mr Bell, Dr Steele, and Mr Fernie, at Broxburn, by means of lighters to "lock 16" on the Forth & Clyde Canal, and afterwards to Grangemouth. Then, again, cargoes of American petroleum may either be discharged at Bowling or Grangemouth, and afterwards he lightered on to Stirling. Indeed, Messrs Shand & Company are the only persons who are practically engaged in the importation from America of the crude petroleum as it run from the oil wells. They likewise consume large quantities of the valuable Rangoon earth oil. The petroleum is shipped for them on an extensive scale at New York and Philadelphia.

At the time of our visit there were two cargoes of oil process of being run ashore at the wharf. The crude oil is kept in the barrels till it is wanted for the first distillation, when the requisite quantity is run into tanks covered with wire gratings to entrap any contained foreign solid matter, such as old bungs and pieces of sticks, and from the tanks it is pumped up into the stills. In the case of the shale oil of this country more labour is required the refining processes than is required by the American petroleum.

We start with the former. It is introduced into the stills to the amount of 1200 or 1300 gallons at a time. The stills used in this process are made of cast-iron, and are heated directly by fires underneath, while in other cases naked steam and super-heated steam are employed. There are ten of them so employed, each of them having a capacity of from 1500 to 2580 gals.; and altogether there are some three dozen in the works, and more ordered. The distillation is conducted to dryness, when the only residue is a quantity of black shining material, which almost pure carbon, and is in great request, as an excellent quality of smokeless fuel, brassfounders and metal-refiners, and even the Bank of England. Twelve to sixteen hours are usually sufficient for completing the distillation; and as these stills are worked off three times weekly, the enormous amount of 1200 or 1500 barrels of crude oil may be turned over within the six days. The quantity of "once-run" oil obtained from the crude material is 92 to 95 per cent, and has the specific gravity varying from -840 to '870. From the stills the condensed oil runs into immense underground receiving tanks, from which it is pumped up into treating boxes, each of which is capable of holding 80 barrels, or about 2500 gallons. Six of these treating boxes are engaged working " once-run" oil at the rate of about 500 barrels daily. In them the oil is subjected to the action of strong sulphuric acid or oil of vitrol, which varies in amount with the quality of the oil treated.

If we remember rightly, Mr James Young's original patent mentioned 10 per cent, of acid. The mixture of oil and acid is agitated by means of an Archimedean screw, working great velocity, till the impurities which are affected by the acid are removed by it. Strangely enough, although it is itself so remarkably powerful as a chemical agent, sulphuric acid has no effect whatever on any of the four individual compounds which collectively make up the "once-run" oil. They remain fixed, unchanged, and undecomposable by it, it only has affinity for the impurities which it is desirable to get rid of. A sufficient length of time being allowed for the subsidence of the heavy acid waste, it is drawn off a low level, and has, as we can vouch, a filthy offensive appearance; but it is not necessarily permitted to go to waste, as we shall show by and by.

The oil which remains in the treating boxes is then subjected, in the same vessels, and by the same means, to the action of equally strong chemical agent, caustic soda, solution, which is employed for the purpose of neutralising and removing any sulphuric acid that may remain amongst the oil, and possibly to remove any other impurities that are not removeable by means of the acid. The agitation is carried on for several hours, and when the mixture has become well settled the oil is drawn off, taken to stills, and distilled to dryness.

The distilled product is again treated and agitated alternately with sulphuric acid and caustic soda, but in smaller quantity than at first. It is then re-distilled with great care, — nay it undergoes what is termed in chemical phraseology " fractional distillation." For some time after the heat is first applied the vapour of a very volatile compound passes over and condenses : this we have previously spoken of as naptha or turpentine substitute. The specific gravity of this substance is about .740, It is eminently a light body, and very inflammable, and when its vapour is mixed with a certain quantity of atmospheric air an explosive mixture is formed. It is very abundant in the American petroleum, and hence an explanation of the numerous explosions which occurred this country when that substance was first brought into use. When properly rectified and in its most purified state, this naptha, or spirit, it is also called, may be used as benzole removing oily or greasy stains, and stains of tar, resin, wax, and paint, from cotton, woollen, silk, and other fabrics, or from hair, furs, feathers, and wools, and for cleaning gloves and other articles made of leather. We may quietly inform our lady house-keeping readers, likewise, that the naptha in question may be used for making excellent furniture paste, by dissolving one par. of resin and one of wax in two parts of the volatile liquid, with the aid of a gentle heat.

The second substance which comes over from the still, following the naptha, is the colourless paraffine oil for burning in lamps, having a specific gravity varying from .805 to .820. Lastly, the process of fractional distillation yields a heavy oil whose specific gravity is about .880. It consists, however, of two products, one of them solid held in suspension, or more correctly, in solution, by the liquid. To effect their separation, the liquid mass is allowed to cool, and is then made to give up its solid ingredient draining in flannel bags, so suspended that the liquid exudation may freely escape and run into tanks having a united capacity of many thousand gallons, where it collects as machinery or lubricating oil. The semi-solid substance which remains the bags is afterwards subjected to great pressure to remove all the liquid material. This effected by expressing it in canvas bags between layers of strong wicker work. The expressed liquid runs away to the common reservoir. The solid which remains a golden-yellow body consisting of aggregated crystalline scales ; it is the parafflne we have previously spoken of.

At the time of our visit to Messrs Shand & Company's Works, the whole of their first year's gathering of paraffine was in stock, but all was contracted for by an eminent, London firm, in whose hands it is thoroughly refined, and then sold to the makers of paraffine candles. The stock which we saw was still in rough state, not properly pressed, as the hydraulic presses were only in course of erection. Including what was stored away at about 200 tons, having a money value, when thoroughly refined, of something like £20,000. What an illumination it would make. We now proceed to speak of the methods employed in the refining of the American petroleum, the processes just now detailed being those which are employed by Messrs Shand & Company alike for shale oil, and that obtained from Boghead and other coals.

The business of this eminent firm began a goodly number years ago, operating upon the refuse of the neigbouring gas-works, with the object making or extracting from that offensive compound the marketable materials known as sulphate of ammonia, coal-tar naphtha, coal-tar oils, and lamp-black. This branch of the business is still continued by Mr Shand s firm ; but with such beginning there was unnatural matrimonial alliance made when the petroleum refining item was added to it. This branch of the business almost exclusively conducted Messrs Shand & Company. The barrels of petroleum being run ashore, the contained liquid is either retained in the barrels, or it emptied into underground tanks, from which it can conveniently be pumped into the stills. It differs very much from shale oil as regards the amount of each of its proximate ingredients. It is purer, and contains more spirit and light or burning oil than does the crude artificial mineral oil, and less lubricating oil and solid paraffine. A mode of treatment somehow different from that given above is therefore adopted. It is first distilled without any acid or alkaline treatment, not to dryness, but leaving instead a residue called " still bottoms," which is run off and used for greasing purposes. This material is well adopted for the machinery of underground works, such as colliery waggons; as it has no smell it has not the usual offensiveness possessed grease preparations where there is a limited circulation of air. The condensed distillate from the stills is collected in casks and puncheons, and them is removed to the treating house.

By a process peculiar to Messrs George Shand & Company, the crude petroleum, as it runs from the wells, is rendered fit for the finishing processes by one distillation. They have six refining stills in operation which are capable of working off 300 barrels three times a week. By carefully conducting the process of distillation, the several distillates are obtained separately in the order of their specific gravities:- lst, the volatile spirit or naphtha- 2nd, the illuminating oil for use lamps; and 3rd the heavy lubricating oil. The solid paraffine is so small in amount in the American petroleum— being only about five pounds in a ton, or 265 gallons— that it is not deemed desirable to make any effort to separate it. All the three products just named are separately treated with acid and caustic soda in succession, in the same way shale oil is treated, but with a much smaller quantity of those chemical agents There is this difference, however, that the agitation along with the acid is not effected in ordinary steam agitators, as it is considered that the oils are injured by the great heat which is generated, if there be not in addition even waste of the volatile products. The treatment with acid and alkali is conducted by manual labour a large one-storey building, in about fifty cast-iron pans, each of them containing 250 gallons. these the liquids are finished. These treating vessels have to stand good deal of tear and wear, the oil of vitriol acting as a powerful corrosive and eating holes in them, which are stopped by plugs of metallic lead, an operation which we saw two men performing when we passed through the building. The refining operations are not wholly finished until the liquids have been thoroughly washed with water. Then the oil is exposed to the bleaching influence of the air and sunlight for a period of time varying from twelve to twenty-four hours, in large shallow iron vessels.

Mr Shand informed us that he considers that the oil is sometimes improved to the extent of two pence per gallon by a day's bleaching. It is ultimately brought to a condition in which it is as clear, colourless, and limpid water, and having odour almost ethereal— indeed it might almost be used instead of eau de Cologne It rises the wick of a lamp with the greatest possible amount of facility. Its temperature of ignition is 105° Fah., while the standard fixed by the Petroleum Act is 100°, so that the Stirling illuminating oil is perfectly safe. When the oil properly bleached, it is either barrelled and sent to St Petersburg, Dantzic, Stettin. Pillau, Konigsberg, Dunkirk, Rotterdam, Christiana, Rouen (for Paris), and many other places, or it is stored in large lead-lined wooden tanks, enclosed within stone walls, and old steam boilers—having a collective capacity of hundreds of thousands of gallons. The arrangements of this enterprising firm are such that, in the busiest season, from 6000 to 7000 barrels of burning oil can be sent out monthly.

Having thus gone into some details regarding the refining operations of Messrs George Shand & Company at their gigantic establishment at Stirling, we may refer our readers to few generalities connected with the business of that firm. First, then, be it known that some time ago the oil refinery at Stirling was the cause of much public dissatisfaction to the lieges of that ancient and royal burgh, being regarded many of them as a nuisance. A cargo of Canadian petroleum had been purchased at an unlucky moment, and true to say, its distillation was not attended with the escape into the atmosphere of the most delicate and sweet-scented perfumes. The murmuring became so loud and prolonged that Mr Shand determined to remove the cause of complaint, and sought out and secured ground to the extent of five acres at Balfron, near the Forth and Clyde Railway. The required buildings were duly erected, and operations commenced. The Balfron works are still continued, and are going through some 800 barrels of crude oil per week. Possession of the ground at Balfron was not peaceably taken either. Several interdicts were threatened, but we believe that none of them have ever yet taken effect.

Instead of Messrs Shand & Company being driven from Stirling they have been confirmed in their possessions and beholdings, and have had additional ground recently secured to them for their business by the municipal authorities of the town. How came the change o'er the spirit of their dream?" The farmers in the vicinity cheerfully admit, nay, affirm voluntarily, that the oil refinery on the banks o' the Forth has been the means of securing their oxen against the ravages of the dreadful cattle plague, as it is reported that not a single case of the disease has occurred within four miles of Sliding, or nearer than Blair Drummond, and even there it was only owing the introduction of an infected beast that had been purchased at the Falkirk Tryst. That nut for the Cattle Plague Commissioners crack If that be not enough we now inform them, and all others whom it may concern, that, of the employees in the Forth Bank Works, not a single case of a contagious disease is on record. There are other facts indicative of the extent of the operations of the firm of Messrs Shand & Company besides those we have had occasion to mention already. They probably turn out more refined oil than any other firm Britain, not even excepting the celebrated Bathgate Works noticed the other day in these columns.

So important to crude oil makers is an enterprising refining firm that oil is carried from all parts of Britain to be refined at Stirling,—one Welsh firm alone, the Coppa Oil Company,—sending 1000 barrels monthly. One naturally led to conclude that the operations of the firm must be extensive, judging even alone by the barrels which he sees. There are probably £10.000 worth these, exclusive of the contents of those which are filled. Each new cask is generally worth about ten shillings, while the American casks are worth from five to eight each. Some of them, as the sperm oil butts, will hold 202 gallons each, and the price is estimated at l.2d .to 1.5d per gallon of contents. The American barrels are depended on chiefly for the foreign trade, and then the price of the cask is included the gross charge, for there is little likelihood of empty barrels being returned from such distant places as St Petersburg. Before they are refilled, however, for exportation, they are thoroughly cleaned and rendered possible. For this purpose one of the ends are taken out, and the inside well steamed for some minutes, and then briskly scoured out with dry sawdust. This material is likewise used plentifully throughout the works for removing the oil from the hand of the workers; it easily obtained, there is a large sawmill adjoining the works. When the barrels are cleaned, and the ends replaced, they are dried and skilfully and expeditiously coated internally with liquid glue - From the barrels, the step to the cooperage is not great. This feature of an oil factory is always a prominent one.

At the Stirling works the cooperage room is equal to seventy men, and fifty out of that number were actually employed during the past season. They are the principal skilled workmen about the establishment; the others are chiefly discharged soldiers. The last-mentioned fact shows that the works are of great use in drafting men into work as they are drafted out of their respective regiments, when occupying the garrison of Stirling Castle. Being situated so near the river Forth, and using such powerful chemical agents as oil of vitriol, it might naturally be expected that the surface drainage of the works would contaminate, the water of the river. But such is not the case. There is undoubtedly a great amount of surface drainage, and it is largely charged with oil. Self-interest alone is sufficient here, for, in the desire to save the oil, numerous wells are provided along the lower levels. These are lined with Roman cement to prevent leakage, divided by partitions, and provided with siphons, so as to collect the oil and water in separate compartments. The former is ladled or pumped out, and the latter is filtered and fitted for use in some of the processes carried on in the work.

Economy is practised in other directions likewise. The sulphuric acid sludge is not discharged into the river, but, instead, is subjected to the action of steam, and thus there is obtained a quantity of inferior pitch, or tar, while the solid portion burned and the smoke made into lamp-black. Messrs Shand & Company have been almost the only makers this substance in Scotland for the last ten years. It is used by the makers of india-rubber goods both in this country and on the Continent, Mannheim Hamburg, St Petersburg, and Paris. It also used for making American cloth, for blackening coffins, for printer's ink, for black paint, and by curriers dressing leather. When Messrs Shand & Company began to make this substance, its price was £4 or £5 per ton, then it was gradually brought up to £ 20 per ton, and now it sells, according to quality, at from £7 to £20, or even £30 per ton, while currier's black commands the enormous price of £50 per ton. The acid of the sludge also economised, being employed in making, with the ammonia water the gas-work sulphate of ammonia for the farmer to manure his crops with. Neither is the soda waste allowed go to loss, it is dried and roasted a reverberatory furnace, and then reduced to the caustic state by the action of quicklime.

As large quantities of fresh and pure water are required the operations of this establishment we were curious enough to inquire of Mr Shand if he depended on the water of the Forth. He informed us that he would have none of it. notwithstanding its proximity to the works. First, because it is not pure enough; and secondly, because it would require pumping to get it, even the Commissioners of the Forth would permit it to be used. A large supply of excellent water is obtained from the reservoir that supplies the town of Stirling. That is up among the Touch Hills. The great elevation of the source of the supply renders pumping quite unnecessary, as it is obtained by the force of gravitation.—

Morning Journal. Reprinted in the Stirling Observer, 1st March 1866