In the race for cleaner and more sustainable transportation fuels, methanol emerges as a strong contender. This simple alcohol, with the formula CH3OH, holds promise for powering cars, ships, and even some industrial applications. It is worldwide available as a marine fuel, cost effective and significantly reduces emissions of sulphur oxides, nitrogen oxides, CO2 and particulate matter.

Let’s delve into the world of methanol as fuel, exploring its properties, its potential, and the safety precautions necessary for its use.

Methanol 101: Chemical and Physical Properties

Methanol is the simplest form of alcohol, also known as the “wood alcohol” as previously was made by pyrolysis of wood, is produced from various feedstocks, but natural gas is currently the most economical method. It’s a colorless, flammable liquid with a distinct odour. Methanol is a biodegradable, water soluble, clear liquid with the chemical formula CH3OH, containing the least carbon and the most hydrogen of any liquid fuel. It is a liquid at atmospheric pressure that ranges between 176 and 338 K (–93°C to +65°C), making storage less expensive than LNG, H2, and NH3. Because of its density and lower heating value (19.5 MJ/kg), methanol necessitates approximately 2.5 times larger fuel tanks than MGO per energy unit, and similar or smaller fuel tanks than LNG.

Compared to gasoline,some key characteristics of methanol to remember are:

• Lower energy density: While methanol can produce similar horsepower to gasoline, it packs less energy per gallon. This means you’d need to fill up more often.

• Higher octane rating: Methanol boasts a much higher octane rating than gasoline, leading to smoother engine operation and potentially reduced emissions.While gasoline octane rating is in the range of 87 to 94, methanol is raging from 100 to 130+. This significantly higher octane rating allows methanol to resist knocking (premature detonation) better than gasoline, enabling the use of higher compression ratios for potentially greater engine efficiency.

• Flammable: Methanol has a higher ignition temperature (meaning it requires a higher temperature to self ignite), but a lower flash point (meaning its vapour can ignite at a lower temperature in the presence of external source) compared with gasoline.

• Miscibility with water: Unlike gasoline, methanol readily mixes with water. This can be advantageous for some applications but requires careful handling to avoid contamination. Methanol is hygroscopic which means that will absorb water vapours directly from atmosphere, which will dilute its fuel value. Also, it contains soluble and insoluble contaminants and chloride ions which have a large effect on the corrosivity by chemically attack of metals causing pitting and by increasing fuel conductivity which leads to electric and galvanic corrosion.

Therefore, methanol has a good combustion, a good energy efficiency and low emission, but to be used in diesel engines requires an ignition enhancer which is a small amount of diesel oil. There are other approaches as well, like glow plug ignition which enables the compression ignition engine to run solely on methanol, without requirement of a pilot fuel to serve as the ignition source. Another solution, especially as a retrofit option is to introduce methanol into engine’s intake ports by adding a low-pressure methanol fueling system and port fuel injectors.

MAN B&W ME-LGI 2stroke dual fuel engine can run on methanol, fuel oil, marine diesel oil, ammonia or gas oil and they have the ability to achieve Tier III NOx standards (2-4 g/kWh) without after-treatment.

The new injection concept enables the exploitation of more low flash point fuels such as methanol, ethanol and LPG and the engine ability to run on these sulphur-free fuels offers great potential for ship operation within SECA zones.

Since the LGI is an add-on to the electronically controlled ME engine, converting an existing diesel engine into a dual-fuel engine capable of using both diesel and, for example, methanol is possible. The diesel fuel system is not majorly changed compared to a standard ME engine. As is the case for the ME-GI, the ME-LGI fuel system can change over to fuel mode, burning diesel oil or HFO from one stroke to the other without any limitation in speed or load.

Methanol as Fuel: Pros and Cons

Methanol offers several advantages as a fuel:

• Reduced emissions: Burning methanol produces fewer harmful pollutants like particulate matter and sulfur oxides compared to gasoline or diesel. This because when burned in engine, methanol undergoes a more complete combustion compared to gasoline.
• Renewable potential: Unlike fossil fuels, methanol can be produced from renewable sources like biomass or captured carbon dioxide. This “green methanol” holds immense promise for sustainable transportation.
• Lower production cost: Production methods for methanol are generally cheaper than other alternative fuels like ethanol.
• Existing infrastructure: Many existing pipelines and storage facilities can be adapted for methanol transportation and storage.

However, there are also some drawbacks to consider:

• Lower energy density: As mentioned earlier, this translates to a shorter driving range on a single tank.
• Material compatibility: Traditional engines require modifications to run efficiently and safely on methanol.
• Toxicity: Methanol is more toxic than gasoline and requires proper handling and safety precautions. Moreover, methanol is toxic in high concentrations as ingestion of 10 ml can cause blindness and 60-100 ml can be fatal. Due its volatility it is not necessary to be ingested to be dangerous since the liquid can be absorbed through the skin and vapours through the lungs. Methanol is much safer when is blended with ethanol.

Same as for ammonia, the use of methanol will lead to major changes in engine room, as the entire treatment of HFO will disappear (settling tanks, purifiers, heaters, booster pumps, viscometers, filters etc.), but new system will need to be installed specific for methanol use.

Safety First: Handling Methanol Responsibly

Methanol is a toxic substance and can cause health problems if ingested, inhaled, or absorbed through the skin. Here are some safety measures to remember:

• Personal protective equipment: Wear appropriate clothing, gloves, eye protection, and respirators when handling methanol.
• Proper ventilation: Ensure adequate ventilation in any area where methanol is being stored or handled.
• Spill response plan: Have a plan in place to address any potential spills or leaks promptly and safely.
• Training: Anyone working with methanol should receive proper training on its safe handling procedures.

By following these safety protocols, we can ensure the responsible use of methanol as a fuel source.

In conclusion, methanol presents a viable option for a cleaner transportation future. Its lower emissions, potential for renewable production, and existing infrastructure make it a compelling alternative fuel. However, addressing its lower energy density and ensuring safe handling are crucial for wider adoption. As research and development continue, methanol holds the potential to play a significant role in a sustainable transportation landscape.

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Source and credit:

• Methanol YouTube video – Methanol Institute
• Engine type You tube video – MAN Energy Solution