Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering

Faculty Mechanical, Maritime and Materials Engineering
Transport Technology / Logistic Engineering

G.J. Kleisterlee Methanol. An overview on production, uses, characteristics, handling and future.
Literature survey, Report 2003.LT.6697, Transport Technology, Logistic Engineering.

Methanol, or Methyl Alcohol, is a colourless liquid at ambient temperatures with a mild, characteristic alcohol odour. It is the simplest of a long series of organic compounds called alcohols. The molecular formula is CH3OH. Methanol is a violent and potent nerve poison and exposure to methanol can cause blindness or death. Methanol is generally considered non-corrosive and is highly miscible with water. It is a clean burning fuel with non-luminous, pale blue flame and forms explosive mixtures with air.

Methanol can be produced from a wide variety of fossil feedstocks, including natural gas, coal, and petroleum but also renewable sources as biomass and municipal waste. Originally methanol was obtained from the destructive distillation of wood but nowadays natural gas is the main feedstock since the combination of gas prices and the process involved with making methanol out of natural gas is the most cost-efficient way. In the future however coal might also be an attractive feedstock since worldwide coal reserves exceed natural gas reserves by far and new more efficient production technologies for making methanol out of coal are on the way. Methanol from biomass would also be a good alternative to natural gas since it is a very environmental-friendly fuel but is comparatively still too expensive.

Methanol is currently produced and used worldwide in a variety of industrial applications, including formaldehyde (37% of the total demand), methyl tert-butyl-ether or in short MTBE (28% of world demand) and acetic acid (8% of world demand). Formaldehyde is mainly used in making plywood and MDF, MTBE as an octane enhancer in automotive fuel and acetic acid mainly as a solvent in chemical reactions.

Methanol is one of the most promising alternative automobile fuels from a non-petroleum source. It can be used directly as a gasoline but an even cleaner use would be in fuel cells. This fuel cell might also be used as a power generator on industrial or domestic scale.

Worldwide, over 90 methanol plants have the capacity to produce about 40 million tonnes of methanol annually. This capacity is not fully utilized since the market for methanol stagnated while new plants were already being built. The reason for this growth decrease is the ban on MTBE in many states in the US. Demand for methanol however will keep on growing and might face an enormous boost when the methanol fuel cell becomes a success in the near future.

Methanol is not carcinogenic but can be highly toxic when ingested. A small doses might already result in irritation to the mucous membranes, headache, sleepiness, nausea, confusion, loss of consciousness, digestive and visual disturbances. Larger amounts can cause narcosis, acidosis (formation of acid throughout the whole body) and even death.

Since methanol is hydrophilic and infinitely soluble in water it dissolves rapidly into the surface in case of a spill. Biodegradation is the primary process for methanol removal from the environment. Aerobic microorganisms play a prominent role in this process. They oxidize organic contaminants by consuming oxygen, leading to the mineralization of methanol. This way methanol spill is turned to formaldehyde and subsequently assimilated into cell material. Relative to gasoline, methanol is safer and milder to the environment. Hazards incurred by gasoline releases are greater than those of methanol releases, and will persist much longer in the environment.

Methanol is stable under normal storage conditions and is not subject to hazardous polymerization reactions, but can react violently with strong oxidizing agents. The greatest hazard involved in handling methanol is the danger of fire or explosion. Therefore precautions such as diking and fire fighting provisions must be taken. For small fires, water or chemical extinguishing agents are adequate. Larger fires may require alcohol-resistant foams for control [M. Howe-Grant, J.I. Kroschwitz, R.E. Kirk, D.F. Othmer Kirk-Othmer Encyclopedia of Chemical Technology vol.16, Wiley, New York (1995)]. Chemical protection may be provided with hermetic clothing, gloves and footwear and a full-face, positive pressure, self-contained breathing apparatus or an air line. Suitable protective materials for equipment include polyvinyl plastic, neoprene or rubber.

Personnel involved in the storage and handling of methanol require eye and skin protection from the irritating properties of methanol in the event of a spill. Contact lenses should not be worn, since plastic lens materials may absorb and concentrate methanol against the eye. Additional respiratory protection is not required with adequate local explosion-proof ventilation [Kirk & Othmer ibid.].

In shipping, methanol is classified by the IMO as a noxious liquid of classification C, requiring a vessel of type III to be shipped in. Though methanol is often shipped across world seas by parcel carriers the amount of dedicated methanol vessels is increasing. One of those ships is the Millenium Explorer, a 100.000 dwt methanol carrier with at least twice the capacity of any other vessel of its type. This tanker is capable of carrying 120.000 tonnes of methanol distributed over 12 cargo tanks with zinc silicate coatings and carries it's own nitrogen generator on board to blanket the methanol in these tanks with inert gas. Common pumping systems to transfer the methanol are electrically or hydraulically driven centrifugal pumps and deepwell pumps and hydraulically driven submerged pumps. Stripping of the cargo is an important feature onboard these tankers.

Completely enclosed equipment is necessary when storing methanol. This avoids ignition and human contact. Furthermore the storage tanks must be vented and, preferably, be equipped with vapour emission controls. In storage areas smoking and open fires are prohibited. Furthermore explosion proof electrical equipment should be used and proper electrical grounding is necessary to protect against lightning strikes and the release of accumulated static electricity [Methanex ibid.]. With methanol an inert gas blanket might be used to prevent oxidation and the build up of explosive vapour. Storage of methanol with incompatible matter should be avoided. Storage tanks of welded construction are normally satisfactory. Copper, zinc, aluminium or plastics are unsuitable for storage. They are attacked slowly and will contaminate the methanol. For long term storage mild steel is the recommended construction material. In shipping, tanks with a zinc-silicate coating are preferred.

Reports on Logistic Engineering (in Dutch)
Modified: 2003.02.13; , TU Delft / 3mE / TT / LT.