bioMSAR™

bioMSAR™ is a renewable version of MSAR® and has undergone extensive pilot testing at QRF to ensure that it’s ready for commercial-scale fuel applications. Below is a summary of application test results to date that demonstrate that bioMSAR™ performance matches our excellent, proven MSAR® fuel and surpasses conventional fuels.

Aquafuel Testing (Cummins Engine)

Ongoing testing of bioMSAR™ at Aquafuel Research Limited facilities has confirmed that bioMSAR™ is viable as a diesel engine fuel, the efficiency is 3% higher than diesel and emissions results indicate 20-27% lower NOx. The bioMSAR™ fuel being tested reduces CO2 emissions by around 20%.

Quadrise’s test engine is a high-speed (1500 RPM) 4-cylinder, 4-stroke direct injection Cummins 4BT. The Cummins engine has been modified to allow new fuels and higher inlet temperatures to be tested. The head and flywheel have been modified to install a pressure sensor and allow fuel injection timing to be adjusted respectively.

The engine efficiency using bioMSAR™ and diesel were calculated at 30kW, and under these conditions bioMSAR™ showed 3% higher efficiency compared to diesel using the standard injection settings, where fuel is injected 3% before piston top dead centre (-3° TDC).

NOx emissions for bioMSAR™ were consistently lower than diesel at 30kW and 40kW loads.

Previous diesel engine tests of MSAR® have shown that advancing injection timing can be helpful in improving fuel combustion and engine efficiency. Earlier injection also simulates combustion at a higher compression ratio, which is useful to predict medium speed 4-stroke and low speed electronic 2-stroke engine performance.

The results below confirm this to be the case for bioMSAR™, with 13% higher efficiency seen when injection timing is adjusted to -12° TDC using an inlet air temperature of approx. 80°C:

The result of advancing injection timing is that the enhanced combustion and efficiency also leads to elevated combustion temperatures and hence NOx emissions.

However, with bioMSAR™ it was possible to reduce the inlet air temperature, such that NOx levels could be reduced by over 30% resulting in emissions 45% lower than diesel.

Final NOx levels thus were lower than the original settings for diesel ( at-3° TDC) and, as a result, testing has shown that much higher engine efficiency can be achieved with bioMSAR™, without increasing NOx emissions.

During testing, particulates were assessed visually with levels for both fuels assessed as light. It was expected that particulates may have been higher for bioMSAR™ compared with diesel during these initial tests, given the test engine is designed for diesel and light fuels, however the pre-atomisation of the hydrocarbon appears to be enabling good carbon burn-out and the avoidance of black soot.

Further testing at Aquafuel has been completed on biomass-derived sugars and methyl-esters, this is available here.

VTT TESTING (Wärtsilä 4R32 ENGINE)

bioMSAR™ was successfully tested on a Wärtsilä type-32, 1.64MW medium speed 4-stroke engine by VTT Technical Research Centre of Finland Ltd, and the fuel’s performance was compared to marine diesel as a reference fuel.

5 tons of bioMSAR™ was manufactured at QRF, using the same formulation used for the Aquafuel tests (i.e. 40% glycerine, 50% heavy oil residue, 10% water).

Highlights from the VTT Wärtsilä 4-stroke bioMSAR™ test are:

• Engine efficiency was higher (up to 7%) than with marine diesel, and is dependent upon load.
• Average CO₂ emissions were 26% lower on a “well-to-wake” basis, due to a combination of the 40% renewable glycerine content of bioMSAR™ and the higher engine efficiency.
• NOx emissions were lower than for prior HFO and MSAR® tests, and comparable to diesel, with further NOx optimisation possible.
• Smoke and particulate levels were very low, as were unburned hydrocarbons emissions, due to efficient fuel combustion.
• The existing fuel pumps and injectors worked well with bioMSAR™.

Reference tests were carried out on marine diesel prior to testing bioMSAR™.  Results are presented below to show how bioMSAR™ performance compares with conventional diesel at 75% load (approx. 1.2MW), which is a typical operating regime for a marine 4-stroke diesel.

Comparative results from prior MSAR® and HFO testing by VTT on the same engine are also shown.

The efficiency of an engine is a function of how effectively fuel energy is converted into power, net of any losses.  Higher engine efficiency results in lower fuel consumption and lower greenhouse gas emissions.

The results show that bioMSAR™ was consistently more efficient than diesel, ranging from 1-7% better at engine loads of 50-90%.

The efficiency results for bioMSAR™ are consistent with prior MSAR® performance testing, which showed an efficiency benefit of over 5% versus HFO at high loads.

The shipping industry is looking to standardise the reporting of climate impact from fuels on a “well-to-wake” life-cycle basis that includes GHG emissions from feedstock extraction, fuel production, transportation and combustion.  These factors are standardised to provided equivalent GHG emissions per unit energy, and have been used to calculate the GHG of bioMSAR™ against diesel below.  The baseline life-cycle GHG emissions from diesel is 90 gCO₂e/MJ, compared with 69 gCO₂e/MJ for bioMSAR™, which is 23% lower due to the renewable glycerine content.  This is comparable with a fuel change to natural gas, but without the risk of methane slip or efficiency loss in the engine.

The overall GHG emissions are also impacted by the efficiency of the engine.  As a result, the CO₂ reductions for bioMSAR™ were 24-29% compared with diesel over the range of normal engine loads (50-90%).

NOx emissions from engines are a function of fuel NOx and thermal NOx, but largely the latter.  The higher the combustion temperature, the higher the thermal NOx, which is produced from the decomposition of combustion air. 

In diesel engines there’s a trade-off between engine efficiency and NOx emissions, with higher efficiency leading to higher NOx emissions generally.

For bioMSAR™, the higher engine efficiency led to NOx emissions comparable with diesel, which contains virtually zero fuel nitrogen.  bioMSAR™’s NOx emissions are lower than prior MSAR® or HFO tests.

Further reductions of bioMSAR™ NOx are possible by tuning the engine parameters, however the VTT test was limited in duration. Further bioMSAR™ NOx optimisation is planned for forthcoming Aquafuel tests. Earlier Aquafuel tests achieved NOx reductions of 20-25% versus diesel on a high speed 4-stroke engine.

Commercial experience on Wärtsilä 4-stroke engines (>150,000 hours) have also shown that >20% NOx reductions are typical for oil-in-water emulsion fuels such as MSAR® over a range of normal engine loads.

PM and smoke emissions from engines are a function of fuel quality and combustion efficiency of the fuel and engine.  The hydrocarbon droplets of bioMSAR™ are “pre-atomised” to enhance combustion efficiency and reduce emissions of smoke, Black Carbon and PM.

Smoke opacity is generally used in the field to quantify black smoke and PM related emissions using a light scattering/absorption device.  The resulting Filter Smoke Number (FSN) is used to quantify the visible smoke.  FSN values for bioMSAR™ were consistently lower than diesel and other fuels tested.

PM emission values for bioMSAR™ were lower than HFO and MSAR®, due to the presence of glycerine that contains negligible ash, but marginally higher than diesel which contains ultra-low sulphur and ash in the fuel.

The results indicate low Black Carbon emissions are achieved with bioMSAR™, as with MSAR®.

The other main pollutants from diesel engines are carbon monoxide (CO) and unburned hydrocarbons (HC), both of which are also impacted by fuel type and combustion efficiency.

Emissions of unburned HC from bioMSAR™ were low as a result of efficient fuel combustion during this short test. Further optimisation of CO is planned for bioMSAR™ in the future, although overall levels for all fuels were low.