Advanced steam technology


Advanced steam technology reflects an approach to the technical development of the steam engine intended for a wider variety of applications than has recently been the case. Particular attention has been given to endemic problems that led to the demise of steam power in small to medium-scale commercial applications: excessive pollution, maintenance costs, labour-intensive operation, low power/weight ratio, and low overall thermal efficiency.
Steam power has generally been superseded by the internal combustion engine or by electrical power drawn from an electrical grid. The only steam installations that are in widespread use are the highly efficient thermal power plants used for generating electricity on a large scale. In contrast, the proposed steam engines may be for stationary, road, rail, or marine use.

Improving steam traction

Although most references to "Modern Steam" apply to developments since the 1970s, certain aspects of advanced steam technology can be discerned throughout the 20th century, notably automatic boiler control along with rapid startup.

Abner Doble

In 1922, Abner Doble developed an electro-mechanical system that reacted simultaneously to steam temperature and pressure, starting and stopping the feed pumps whilst igniting and cutting out the burner according to boiler pressure. The contraflow monotube boiler had a working pressure of but contained so little water in circulation as to present no risk of explosion. This type of boiler was continuously developed in the US, Britain and Germany throughout the 1930s and into the 1950s for use in cars, buses, trucks, railcars, shunting locomotives, a speedboat and, in 1933, a converted Travel Air 2000 biplane.

Sentinel

In the UK, Sentinel Waggon Works developed a vertical water-tube boiler running at which was used in road vehicles, shunting locomotives and railcars. Steam could be raised much more quickly than with a conventional locomotive boiler.

Anderson and Holcroft

Trials of the Anderson condensing system took place on Britain's Southern Railway between 1930 and 1935. Condensing apparatuses have not been widely used on steam locomotives due to the additional complexity and weight, but they offer four potential advantages:
The Anderson condensing system uses a process known as mechanical vapor recompression. It was devised by a Glasgow marine engineer, Harry Percival Harvey Anderson. The theory was that, by removing around 600 of the 970 British thermal units present in each pound of steam, it would be possible to return the exhaust steam to the boiler by a pump which would consume only 1–2% of the engine's power output. Between 1925 and 1927 Anderson, and another Glasgow engineer John McCullum, conducted experiments on a stationary steam plant with encouraging results. A company, Steam Heat Conservation, was formed and a demonstration of Anderson's system was arranged at Surbiton Electricity Generating Station.
SHC was interested in applying the system to a railway locomotive and contacted Richard Maunsell of the Southern Railway. Maunsell requested that a controlled test be carried out at Surbiton and this was done about 1929. Maunsell's technical assistant, Harold Holcroft, was present and a fuel saving of 29% was recorded, compared to conventional atmospheric working. The Southern Railway converted SECR N class locomotive number A816 to the Anderson system in 1930. The locomotive underwent trials and initial results were encouraging. After an uphill trial from Eastleigh to Litchfield Summit, Holcroft is reported as saying:

"In the ordinary way this would have created much noise and clouds of steam, but with the condensing set in action it was all absorbed with the ease with which snow would melt in a furnace! The engine was as silent as an electric locomotive and the only faint noises were due to slight pounding of the rods and a small blow at a piston gland. This had to be experienced to be believed; but for the regulator being wide open and the reverser well over, one would have imagined that the second engine was propelling the first."

The trials continued until 1934 but various problems arose, mostly with the fan for forced draught, and the project went no further. The locomotive was converted back to standard form in 1935.

André Chapelon

The work of French mechanical engineer André Chapelon in applying scientific analysis and a strive for thermal efficiency was an early example of advanced steam technology. Chapelon's protégé Livio Dante Porta continued Chapelon's work.

Livio Dante Porta

Postwar in the late 1940s and 1950s some designers worked on modernising steam locomotives. The Argentinian engineer Livio Dante Porta in the development of Stephensonian railway locomotives incorporating advanced steam technology was a precursor of the 'Modern Steam' movement from 1948. Where possible, Porta much preferred to design new locomotives, but more often in practice he was forced to radically update old ones to incorporate the new technology.

Bulleid and Riddles

In Britain the SR Leader class of c. 1949 by Oliver Bulleid and the British Rail ‘Standard’ class steam locomotives of the 1950s by Robert Riddles, particularly the BR Standard Class 9F, were used to trial new steam locomotive design features, including the Franco-Crosti boiler. On moving to Ireland, Bulleid also designed CIÉ No. CC1 which had many novel features.

Achieving the ends

The Sir Biscoe Tritton Lecture, given by Roger Waller, of the DLM company to the Institute of Mechanical Engineers in 2003 gives an idea of how problems in steam power are being addressed. Waller refers mainly to some rack and pinion mountain railway locomotives that were newly built from 1992 to 1998. They were developed for three companies in Switzerland and Austria and continued to work on two of these lines. The new steam locomotives burn the same grade of light oil as their diesel counterparts, and all demonstrate the same advantages of ready availability and reduced labour cost; at the same time, they have been shown to greatly reduce air and ground pollution. Their economic superiority has meant that they have largely replaced the diesel locomotives and railcars previously operating the line; additionally, steam locomotives are a tourist attraction.
A parallel line of development was the return to steam power of the old Lake Geneva paddle steamer Montreux that had been refitted with a diesel-electric engine in the 1960s. Economic aims similar to those achieved with the rack locomotives were pursued through automatic control of the light-oil-fired boiler and remote control of the engine from the bridge, enabling the steamship to be operated by a crew of the same size as a motor ship.

Carbon neutrality

A power unit based on advanced steam technology burning fossil fuel will inevitably emit carbon dioxide, a long-lasting greenhouse gas. However, significant reductions of other pollutants such as CO and NOx are achievable by steam compared to other combustion technologies, since it does not involve explosive combustion, thus removing the need for add-ons or special preparation of fuel.
If renewable fuel such as wood or other biofuel is used then the system could be carbon neutral. The use of biofuel remains controversial; however, liquid biofuels are easier to manufacture for steam plant than for diesels as they do not demand the stringent fuel standards required to protect diesel injectors.

Advantages of advanced steam technology

In principle, combustion and power delivery of steam plant can be considered separate stages. High overall thermal efficiency may be difficult to achieve, largely due to the extra stage of generating a working fluid between combustion and power delivery attributable mainly to leakages and heat losses.
The separation of the processes allows specific problems to be addressed at each stage without revising the whole system every time. For instance, the boiler or steam generator can be adapted to use any heat source, whether obtained from solid, liquid or gaseous fuel, and can use waste heat. Whatever the choice, it will have no direct effect on the design of the engine unit, as that only ever has to deal with steam.

Early twenty-first century

Small-scale stationary plant

This project mainly includes combined electrical generation and heating systems for private homes and small villages burning wood or bamboo chips. This is intended to replace 2-stroke donkey engines and small diesel power plants. Drastic reduction in noise level is one immediate benefit of a steam-powered small plant. Ted Pritchard, of Melbourne, Australia, was intensively developing this type of unit from 2002 until his death in 2007. The company Pritchard Power stated in 2010 that they continue to develop the stationary S5000, and that a prototype had been built and was being tested, and designs were being refined for market ready products.
Until 2006 a German company called Enginion was actively developing a Steamcell, a micro CHP unit about the size of a PC tower for domestic use. It seems that by 2008 it had merged with Berlin company AMOVIS.
Since 2012, a French company, EXOES, is selling to industrial firms a Rankine Cycle, patented, engine, which is designed to work with many fuels such as concentrated solar power, biomass, or fossil. The system, called "SHAPE" for Sustainable Heat And Power Engine, converts the heat into electricity. The SHAPE engine is suitable for embedded, and stationary, applications. A SHAPE engine has been integrated into a biomass boiler, and into a Concentrated solar power system. The company is planning to work with automobile manufactures, long-haul truck manufactures, and railway corporations.
A similar unit is marketed by Powertherm, a subsidiary of Spilling.
A company in India manufactures steam-powered generators in a range of sizes from 4 hp to 50 hp. They also offer a number of different mills that can be powered by their engines.
In matter of technology, notice that the Quasiturbine is a uniflow rotary steam engine where steam intakes in hot areas, while exhausting in cold areas.