Europa’s largest methanol plant
I recently visited the Tjeldbergodden industrial complex operated by Statoil ASA. This plant represents 25% of Europe’s total methanol production and 13% of the continent’s consumption. The annual capacity is about 900 000 tones of methanol (more than 100 tones per hour). Tjeldbergodden derives its natural gas feedstock from the Heidrun field in the Halten Bank area of the Norwegian Sea. The natural gas is extracted and pretreated on the platform before compression and injection in the Haltenpipe which makes the connexion with the industrial complex at the coast.
Natural gas is mainly known as a fuel for heating or power production. However, natural gas is also used as raw material for many chemical products. Actually, natural gas can be converted to syngas (a mixutre of CO and H2) which is the common intermediate to methanol, ammonia, gas-to-liquids fuels and many other chemicals synthesis.
The Lurgi boiling water reactors
Since I introduced the reforming reaction in previous articles, I will now focus on the methanol synthesis step. The synthesis reaction is highly exothermic and the reactor is consequently an important source of energy for the whole process. In Tjeldbergodden, the methanol reactors are recovered by a jacket in which steam is generated from cold water. This steam is then used for the reforming step and hot utilities.
Such a large natural gas based plant comprises many risks. Moreover, methanol has a high toxicity in humans. If ingested as little as 10mL, for example, pure methanol can cause permanent blindness. Thus are the safety considerations at Tjeldbergodden very important.
The safety system is designed to be robust enough to detect any kind of error, including human errors. The system comprises many barriers in order to treat any combination of errors with acceptable consequences. Actually, human behaviour is often very decisive in major accidents. So, safety is not just about procedures, it is also about what is going on in employees’ minds. That’s the reason why, for example, checklists should not be too long considering the risk of losing the workers focus.