Petrochemicals and LPG/LNG
Petrochemicals
In 1920 Jersey Standard researchers produced rubbing alcohol, or isopropyl alcohol, the first commercial petrochemical, in the UK Shell set up a separate Petrochemicals Division in the 1920s. Petrochemicals have developed into a major aspect of oil industry, most modern plastics are made from petroleum based feed stock. Petrochemicals are also used in the manufacture of solvents and detergents and for making fibres such as nylon.
Commonly produced petrochemicals include a range of gasses which can be compressed to a liquid at reasonable temperatures: Ammonia, Butane, Butadiene, Ethane, Propane and Pentane are all routinely shipped as LPG in rail tank wagons. Genuine liquids include hydrogen peroxide, heptane, hexane and cyclohexane, used in the manufacture of paint and varnish removers and as feed stock for other chemicals (some of the English China Clay slurry tank wagons are actually redundant four wheeled cyclohexane tanks re-mounted on bogie chassis). Petroleum coke is a black granular form of carbon and shipped either in bulk or bagged, urea is shipped in bulk in the form of pellets (called 'prills') and quite large quantities of sulphur are recovered from some oils, shipped out in bags or drums.
In the post World War two era methanol (see Chemical Industries - Alcohols) has been associated with refineries where it is made using LPG. A typical petroleum gas based methanol plant is a classic 'tall silver towers' installation with a lot of associated pipework. They tend to be long rectangular instalations, the illustration below has been altered to reduce the width by about 50 percent. This still has all the essential elements but it would take a lot of bent metal wire for the pipework.
Fig ___ LPG based methanol plant
Methanol is a type of alcohol however it is poisonous. Its main use is in making formaldehyde (which is then used to make a range of other products). In the 1970s and 1980s it was used to make the petrol additive methyl tert-butyl ether (MTBE) as a replacement for tetraethyl lead. It has been transported in rail tanks since the 1930s (possibly earlier), it is a Class A liquid.
Fig ___ ICI Class A tank wagon for Methanol (pre World War Two)
The sketch below is a chlorinated paraffin wax plant, which could be incorporated into a generic chemical works or as part of a refinery producing petrochemicals.
Fig ___ Chlorinated paraffin wax plant
Petrochemicals have proved a valuable resource for chemists and there have been some quite serious suggestions that oil should not be used as a fuel but should be conserved for use in making these chemicals. Current estimates are that we should run out of petroleum in about the year 2050, although the increasing costs of recovery will be passed on to the consumer and this should slow things down.
Liquefied Petroleum Gas (LPG) and Liquid Natural Gas (LNG)
LPG's include propane, butane and various more exotic gasses. The first two are routinely used for heating but propane cannot be used indoors as the products of combustion are poisonous. One slight problem is that butane is a liquid at below about -5 degrees Celsius, so it is no use as a fuel in cold climates. LPG was produced in Britain by the Riverside Oil Co around the turn of the century although there was little interest in it at the time. In America however things moved rather more quickly and by the time of the First World War the Americans were using butane for domestic heating and cooking. The idea was taken up by the French and in about 1935 the Modern Gas and Equipment Company was set up in Britain to sell imported French 'Calor Gas'. This became the Calor (Distributing) Co. Ltd., a British registered company (for many years this was owned by the Imperial Continental Gas Association, set up in 1824, Calor Gas was sold to the SHV Gas Group, a private Dutch company, in 1984).
Customs officers felt that butane was a rather dangerous material to be shipped across the channel so supplies were purchased from Shell Mex and BP, both of whom viewed it as a waste product at the time. As no British firm had ever made gas cylinders the Home Office and ICI (who were making petrol from coal at Billingham with butane as a by-product) devised a British specification.
In 1936 dealerships were established to sell cylinders of calor gas, each dealer was given an eight horsepower Fordson van, and supplies were delivered in cylinders by rail.
Fig ___ Calor Gas Dealers Van
Up to 1947 all distribution relied on rail transport, but following that hard winter Calor began using road haulage as well (although I am not sure why this was). In the 1960s the bulk gas rail tanks appeared, followed by the larger bogie tankers. As far as I know there were no calor gas liveried tank wagons, but I could be wrong on that point. Eventually the dealers set up larger storage and bottling plants and these were supplied by rail tank wagons either running onto private sidings or decanting into road wagons (this was NOT done at normal goods yards).
If your layout is based in the 1960's or later you might consider a simple transshipment point for LPG to feed road tankers (the first LPG tanks, similar to the Peco offering, appeared in 1962, see also 'Livery - Tank Wagons'). Facilities at a remote LPG depot can be quite small, perhaps only taking two, three or four of the Peco fifteen foot wheelbase tank wagons, a 'reach wagon' would be stored at the terminal used so the loco would not enter the loading area. Four four-wheel Peco tanks occupy the same length as two Farish bogie tank wagons (these latter have to be converted to LPG tankers, introduced in 967, see also 'Goods Rolling Stock Design - Rail Tanks').
There will be a concrete area with rails inset into it surrounded by a low wall to contain spillages, there should be a low gate to close off the entrance to this area and fitted with a sealing rubber strip along the bottom edge.
As the railway tanks did not carry pumps there was usually a small pump in a hut close by the siding. Small hydrants will be located alongside the track for coupling up the discharge pipes, generally a 2 inch and a four inch pipe were provided. If it is a busy terminal there might be some hoses left connected to the hydrants, these are dark grey or natural metal steel reinforced flexible hoses about a foot thick, the coiled metal guitar string 'D' is about right for this. These metal flexible hoses, called Anaconda Hoses, are expensive and most of the pipe-work would be solid metal tubing, either buried or carried above the ground on a steel framework.
There was an article on such a small LPG terminal in Model Railway Constructor magazine, unfortunately I cannot confirm the date but I believe it was in the early 1980's. The rail tankers are available in 'N' from the Peco range and bogie LPG tankers can be produced from the Grafar 100 ton bogie tanker.
xxx confirm date of article if possible
Fig ___ LPG Loading/Discharging point
There would also be a water rail feeding sprays along the railway siding and you need the small stores building shown on the sketch to hold the various items of test equipment and the earthing clamps which would be fotted to any vehicle prior to handling cargo.
The tanks themselves could be located a short distance away, and hence do not need to appear on the layout. The British favoured pressurised tanks, generally large horizontal types. The only photo I have of this type of tank was supplied by Graham Davies, it actually shows the arcton gas tanks at an ICI plant at Runcorn in Cheshire, but the basic size and shape seems to have been fairly standard at about 12 foot diameter (4m) 35-60ft (10- 18m) long (occasionally 80 ft but these were rare). I believe that most LPG depots in the UK had only one row of tanks, not double stacked as shown here, a typical LPG depot might have 4 propane and 6 butane tanks with about a dozen open sheds housing the bottle filling gear.
Fig ___ Arcton pressurised gas tanks
There would typically be a lorry loading point, normally a couple of hundred yards from the railway siding. The lorry loading point will have a metal framework to support a set of water-spray pipes in case of a fire (the standad water pipe feeding the sprays was 12 inch (30cm) in diameter). Somewhere on the site would be the gas bottle filling sheds, open structures with pitched corrugated iron roofs.
Liquid Natural Gas
LNG is a very different animal, methane is the major component of natural gas, about 87% by volume, and this stuff only liquefies at -161 decrees C. or under very considerable pressure (about 60Kg per square cm if I remember correctly). This makes it exceptionally difficult to transport in road or rail tankers as a liquid as the pressure vessel has to be very heavy or the insulation very thick and the refrigeration plant required is much to big to be portable. The bulk LNG ships simply insulate their tanks and use the boil-off in their main engine. Naturally occurring LNG also contains significant quantities of ethane, propane, butane, and pentane (heavier hydrocarbons which are removed prior to its use as a consumer fuel) as well as carbon dioxide, nitrogen, helium and hydrogen sulfide. Having said which it is not toxic (unlike coal gas) and supplies are fairly plentiful at the moment. Compared to other hydrocarbon fuels burning methane produces only carbon dioxide and water and less CO2 than the other fuels.
UK imports of LNG began in 1964 with a shipment for Shell Oil from Algeria carried in the S.S. Methane Princess (LNG is only carried in purpose built ships) and more recently gas from the North Sea oil fields and since the early 21st Century it has been imported via pipelines from Europe and Russia.
LPG (butane and propane) has a higher calorific value than LNG so LPG can not simply be directly substituted for natural gas. However LPG can be mixed with air to produce a synthetic natural gas (SNG) that can be used with equipment designed for LNG.
^
Go to top of page