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Tough task in sludge and slime

4/4/2016 | Words: Ulrich Heyden | Pictures: Ulrich Heyden

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Mud, moisture and clouds of dust are hardly ideal conditions for reliable engine operation. Despite these challenges, Series 1600 engines deliver outstanding performance at the Donskoi Kamen stone quarries in southern Russia.

A siren wails at the Donskoi Kamen stone quarry in Russia. The road down to the workings 50 meters below has been blocked by two trucks. Everyone on site knows that access to the pit is now forbidden because blasting is about to start. An explosion reverberates around the 50-hectare oval pit that the quarrymen have drilled and blasted in the earth over the last nine years, and a yellow-white cloud of stone dust billows upward. The Donskoi Kamen site is an opencast sandstone mine. It provides good access to the workface not too far below the surface and is well located to link with the major M4 highway that connects southern Russia and the port of Novorossiysk with Moscow.

Year on year, the quarry team extracts 6 million tons of stone from the earth at the site, but only a little over half of that goes for the production of aggregates. The rest is spoil that constantly adds to a giant heap. Initially, the stone is loosened by blasting. Excavators then load it onto trucks that haul it to the company’s on-site crushing facilities. Depending on its ultimate use – for highway construction, concrete manufacture or shoreline and riverbank stabilization – the stone is then reduced to different grades. The finished product is dispatched to customers by truck or is stored on site until it is needed.

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Giant crushing machines reduce the quarried stone to different
grades suitable for their ultimate purpose.

Founded in 2006, the Donskoi Kamen company swiftly spotted trends during the economic boom of the time: the demand for quarry stone and aggregates rocketed. The first major customer for stone aggregate was a construction company working on the long-distance Moscow to Sochi highway nearby. The work was part of an investment project for the Winter Olympics. Donskoi Kamen is currently supplying two construction sites linked to the 2018 Football World Cup: a new airport and a football stadium in the Rostov region.

In 2009, when the business had found its feet, the company began to look for smaller new generators to power the three large stone crushing plants. These had to be largely immune to the choking influence of dust (a large 2,000 kW engine had just failed due to dust contamination). Company management decided on an initial purchase of three MTU Series 1600 diesels. Producing 668 kW, the units were small, but they fitted in perfectly with Donskoi Kamen’s new energy concept that involved installing small engines in parallel in three production units. That way, if one engine failed, it could be immediately replaced by others.

Today, Donskoi Kamen operates 17 MTU Series 1600 engines. Together, they generate 8.5 MW of electricity for the three large stone crushing plants. The engines are not operated at maximum performance but are regulated to produce 550 kW of electric power, leaving a backup power reserve. The company is now planning the purchase of four more MTU engines. These will provide a reserve in case of problems and can also be called on in periods of particularly heavy load such as during very hot summers.

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Valery Gromov, Chief Engineer at Donskoi Kamen, is always on the
look-out for favorably-priced German technology.

Never-ending struggle
With its huge, spiderlike crushing plants and its fleets of trucks and shovel excavators, the quarry site is an exciting but hazardous place. The thunder of the grinding machines and the constant roar of engines mean that noise levels remain permanently high.

In January, icy conditions mean the thermometer stubbornly shows temperatures down to minus 10°C. Sleet and slush transform the site into a mire of treacherous puddles and mud. At the other end of the scale, when summer temperatures reach up to 30°C, it is stone dust from the crushing plants that tests both men and machines to the limit. Despite on-site sprinkler systems, the dust is all-pervading.

The production of grit, gravel and chippings keeps the 530-strong workforce hard at work three shifts a day. The 12-cylinder MTU engines run between 12 and 20 hours a day. Because of the heavily dust-laden air, engines are fitted with heavy-duty filters with cyclone pre-separators, but the filters still have to be replaced every day.

The biggest crusher unit is not too far from the administration building. This is a ThyssenKrupp unit and Valery Gromov, Chief Engineer at the quarry, takes pride in recounting how it was put together from components purchased second-hand all over Europe. When the company was founded in 2006, that was the cheapest way to get hold of good-quality German technology. Despite their lack of familiarity with the equipment, the company’s Russian technicians somehow managed to put the whole thing together successfully.

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Donskoi Kamen has decided not to use dust-tight enclosures
for its engines. Heavy-duty air filters with cyclone pre-filters ensure
that dust does not penetrate the engines. Nevertheless,
the engines need to be cleared of dust every day.

What were the reasons behind Donskoi Kamen’s decision to purchase MTU engines in 2009? Gromov still clearly remembers that the main issue was how to make up the 2 MW requirement. “It couldn’t be done with the generators we had at the time. We would have had to buy a large generator, and that wasn’t an economical solution. You don’t want to start up a 2 MW generator if you only need 500 kW for one section of the plant.”

Michail Pridanov, head of a service company for large engines near Moscow, advised the quarry company to buy Series 1600 engines from MTU. The 12-cylinder MTU unit had just appeared on the market and the signs were that its outstanding emissions performance meant it was likely to find favor with the Russian authorities over the long term. Compared with products from other manufacturers, the MTU engine was also favorably priced. In addition, the engine also benefited from a simple construction that made repairs straightforward, explained the service engineer. So far, service staff have carried out work on six of the 17 engines. The oldest unit ran for five years  before it was repaired for the first time.

Communication between MTU and the customer is made much easier because Pridanov speaks perfect German. He learned the language during his work on transport logistics when the Soviet military withdrew its technology from the GDR in 1994. At the time, Pridanov was in charge of a repair team and was thus in constant contact with members of the Bundeswehr. His company, Prom Dizel, has been responsible for servicing MTU engines at the quarry since 2009. Major maintenance procedures are carried out at the service company’s facility near Moscow. Prom Dizel has been MTU Russia’s official service partner since 2015.

Another reason for buying MTU engines, said Gromov, was that Series 1600 units reacted better to varying load demands than competitors’ engines. During the stone-grinding process, engine loading fluctuated between 200 and 600 amperes, he explained. “The diesels that had been in use before only had mechanical injection,” said Pridanov. “They were not able to respond quickly to changing loads. MTU engines have really good load surge characteristics,” added Gromov.

The MTU engines were also outstanding in terms of fuel consumption, said engineer Gromov: “In operation in our partial-load mode with variable load, an MTU engine generating 650 kW uses 45 liters an hour.” That is not a huge amount considering that a truck loaded with stone aggregate needs 50 liters of fuel to cover 100 kilometers.

Keeping a keen eye on costs
One very surprising feature is that the MTU engines are housed next to each other in unsealed, sheet metal boxes. The dust gets in and that can lead to problems and cause engine damage, explained Pridanov. Unfortunately, modern, hermetically sealed enclosures for diesel engines are still too expensive, and the operators would therefore have to do without cosmetic niceties until the essential basic capital was available, said service engineer Pridanov.

Making savings obviously comes at a price. Workers constantly have to invest time to keep the crushers and engines free of dust and clear of the grey sludge it leaves after every shower of rain. They need brushes, scrapers and cleaning materials for their never-ending efforts. Even the power cables that run from the boxes are not laid in protective ducts but simply lie on the ground.

“Cosmetic factors are not a priority. The main thing is to keep production running,” said Pridanov. And run it does! Since 2006, production of chippings and other grades of stone aggregates has increased from 500,000 tons to an average of 3.5 million tons a year. It has been calculated that construction of a new 10-kilometer stretch of four-lane highway will require 300,000 tons of stone aggregate for the foundations alone.

The engine control technology utilized for the first power generation unit that supplies the big ThyssenKrupp stone-crushing plant is state-of-the-art. Performance is synchronized by special-purpose software that ensures equal current intensity from the eight engines as well as availability of the 50 Hz grid frequency required. The synchronization concept also ensures that even the slightest deviations in engine speed are balanced out.

Zero interest in the public grid
Why was the quarry not linked up to the public grid? That would have meant the operators building an extremely long power line at their own expense, explained Pridanov. Gromov added that the operators also wanted to avoid the possibility of public grid outages and claims by the electricity company in respect of purported unpaid bills.

Efficient communication with the engineers at MTU is vital for smooth production, and in this context, both Russian engineers are extremely satisfied. To ensure that they are able to deal personally with most eventualities, Pridanov and Gromov have both completed two training courses at MTU-HQ in Friedrichshafen. Instead of having to fly MTU engineers out to southern Russia for every hiccup, the two Russian specialists can now deal with many situations themselves. Gromov now has flash memory card access to MTU engine control systems and can connect his laptop directly to the 12-cylinder units for engine diagnosis. He then simply transmits the diagnostics protocol by Internet to the MTU Service Section, which provides troubleshooting advice. According to Gromov, the MTU Service Section sometimes also provides software updates.

The enormous climatic variations that are commonplace in some Russian regions can mean that anyone trying to cut corners on the cost of machinery and equipment can have major problems. Engineers at the quarry learned that lesson very early on. "The first winter after we bought the MTU engines was the hardest,” said Pridanov. “At that point, we had not had any MTU training. At temperatures around minus 10°C, we had problems with the diesel fuel.” However, the issues involved were resolved before the onset of the following winter. What was the problem? The low temperatures meant that the diesel fuel became so thick it would not pass through the filters. Tank heating systems etc. could have been fitted as a solution. “But why should we do that when the problem only comes up for two weeks a year at most?” asked Pridanov. The quarry is located in southern Russia, where periods of extreme cold are usually short-lived.

The technicians at Donskoi Kamen also had another problem: High quality diesel fuel is not readily available in southern Russia. Consequently, the quarry now purchases its diesel in the Volga region where the winters are even colder and winter diesel is in greater supply.

According to service engineer Pridanov: “Our experience with the MTU Series 1600 units at the quarry in the Rostov region shows that they are extremely well suited to the rugged conditions in Russia.” Chief Engineer Gromov confirmed the verdict: “The decision to purchase MTU engines was the right one.”

The content of the stories reflects the status as of the respective date of publication. They are not updated. Further developments are therefore not taken into account.

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