Portable compressors: next generation engines explained

By Murray Pollok01 February 2012

Doosan Portable Power’s new 12/250 complies with the latest Stage 3B engine emissions yet occupies a

Doosan Portable Power’s new 12/250 complies with the latest Stage 3B engine emissions yet occupies a smaller footprint than its predecessor, the 12/235.

It is the turn of engines in the 75 to 130 kW bracket to get the Stage 3B/Tier IVi emissions treatment. IRN reports on how two portable compressor specialists - Doosan Portable Power and Atmos Chrast - will meet the new regulations. Plus, news of a new compressor re-rental force in Europe.

This is another significant year for compressor manufacturers as Stage IIIB (Europe) and Tier IV Interim (US) emission limits for engines in the 56 to 130 kW ranges come into force in January 2012.

This follows on from the implementation of similar limits for engines above 130 kW from January last year - and which led to price increases of more than 40% for compressors in these sizes. January 2013 will see the same stricter limits imposed on engines in the 37 to 56 kW range.

Compared to Stage IIIA, Stage IIIB requires a reduction of 90% in Particulate Matter (PM) and 50% in Nitrogen Oxides (NOx). Stage IV will come into effect in 2014 and will reduce NOx by an additional 80%, almost completely eliminating both PM and NOx emissions.

Although engine emission limits have been falling since 1996, for owners of equipment it is these Stage IIIB/Tier IVi limits that will have a big impact, since in most cases engines require sophisticated fuel injection technology coupled with exhaust gas after-treatment that is more expensive than traditional engines and also bring specific maintenance requirements.

Doosan Portable Power, for example, says the best option is the use of EGR (Exhaust Gas Recirculation) combined with DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). This is the same technology being used by Atlas Copco Portable Energy.

DOC and DPF are required because the EGR system, while reducing NOx, actually increases PMs. The DOC is a catalyst that transforms PM emissions in the exhaust into harmless substances, and the DPF filters the exhaust to remove PM.

To keep the DPF clean and working efficiently, the high temperature exhaust gases are used to burn accumulated PM off the DPF, a semi-automatic process called Regeneration.

In meeting the technical challenge set by the new limits, Doosan says it wanted to ensure that compressor performance is maintained or improved and that the technology is rigorously tested and reliable. In addition, it says the new engines have to be easy to use and it will provide training support.

The first Doosan portable compressors to meet the latest Stage IIIB regulations are based on a new common platform, covering five different models with free air deliveries from 21.5 to 30.0 m3/min. The compressors are powered by a Cummins QSL9 engine incorporating EGR, DOC and DPF after-treatment.

The Stage IIIB models, which will be launched at Intermat next April, have been given new designations - 9/275, 9/305, 12/250, 17/240 and 21/220 - to distinguish them from the current Stage IIIA models in the same capacity range, the 9/270, 9/300, 12/235, 17/235 and 21/215 compressors.

The emission regulations give manufacturers some flexibility in selling existing stock after the January 2012 deadline, so in practice, both ranges will be available "for some time in 2012".

Doosan says the full specifications of the new range have still to be confirmed, but the pre-series 12/250 model will actually offer a reduced size and higher flow: 25 m³/min compared to 23.5 m³/min previously.

The 12/250 has a completely new control system with a full colour digital display, and a WiFi interface allows for live streaming of data to operators or to a technician's laptop, tablet or smartphone. Standard features include multiple air outlets, a 110% bunded base, central drains and forklift slots.

This issue of flexibility is illustrated also by what Czech republic manufacturer Atmos Chrast is planning for 2012. The company will launch the 7 m3/min class PDP70, driven by a 70 kW Perkins 1104D-44T engine. This unit will replace a Cummins-powered CompAir C76 model that Atmos was previously selling under its own brand.

Vit Linhart, president of Atmos Chrast, tells IRN that, for the time being, "the employed engine is Stage IIIA and we will use partly the flexibility rules for the coming year adding DPF solution if requested by customers. The genuine IIIB engine from Perkins will be added during next year and the machine is designed in a way that allows this."

The new unit, which expands Atmos' range of portable compressors in the 2 to 10 m3/min range, has "a generous power margin, ensuring reliable and long-life operation."

The company - which has recently invested €1.5 million in its components operation - also makes the point that although Stage 3B limits for engines above 75 kW become a requirement in January this year, "Some of the city councils in Germany, Austria and Switzerland are asking for lower emission limits even for machines with smaller engines than 75 kW. For such customers Atmos is supplying a particle filter solution as a factory option."

Meanwhile, Atmos reports that it is cooperating with Ramirent in the Czech Republic, Slovakia and Poland, all markets where Atmos has good aftersales service networks. Contracts are also being negotiated for the Ukraine, Russia and Baltic countries. Covered by the agreements are Atmos gensets, both portable and stationary, and portable air-compressors.

BOX STORY
Big compressor re-rental launch

Belgian used equipment dealer Machinery Resale bvba has established a new division called MR Air Force to supply large compressors on long-term contracts to rental companies, equipment dealers and agents.

Although not strictly a rental company, MR Air Force will offer a range of re-rental and ‘flex-rent' deals from 6 to 36 month in duration. The company has made an initial order for 40 new compressors from Doosan Portable Power and may increase that to 60.

Henk Uphoff, managing director of MR Airo Force and Machinery Resale, said the new business represented a significant expansion of Machinery Resale and would complement the used equipment operation.

"We see ourselves as a ‘facilitator'", said Mr Uphoff, "a services supplier to all key compressor players with a need for renting out large and high pressure units and we can offer a range of flexible packages to suit different requirements."

He said the service would be aimed at countries in the European Union and that they had chosen Doosan because the machines "are well known in the market...Parts are very accessible within the EU and the machines keep their value even after several years in the rental market."

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