What is the limit for the specific steam consumption of pure methanol in methanol production plants?
Thread Content
Over the past two years, methanol prices have remained stable, but upstream raw materials such as natural gas, coal, and oil are at high prices, resulting in losses for methanol producers. In production facilities, the distillation system accounts for the majority of the energy consumption; it is therefore essential to reduce the specific consumption of dimethyl methanol vapor. Currently, the energy consumption of various companies using the conventional three-column process is around 1.1 tons of steam per ton of purified methanol, and the energy-saving effect of using steam condensate to supply heat to the pre-column is not very significant. Currently, a company in Xinjiang and a company in Yunnan are using a new coupling process that eliminates the need for additional tower equipment; as a result, the steam consumption per unit of pure methanol has been reduced to around 0.85–0.9 (with ethanol levels below 20 and water levels below 50). This results in a significant reduction in energy consumption and substantial cost savings. But this is far from the minimum goal for energy conservation and consumption reduction; so what is the lowest possible level for the consumption of pure methanol? It is currently known that Tianjin Aozhan Xingda can achieve levels below 0.7, which is already quite impressive; is it possible to achieve even lower energy consumption?
1. Steam consumption depends on the concentration of crude methanol; for example, the concentration of crude methanol in methanol produced from natural gas is around 82%, while it is approximately 92% in methanol produced from coal, resulting in a significant difference in steam consumption between the two； 2. The limit you mentioned is actually the theoretical consumption; with zero heat loss in the entire distillation unit, and the vaporization latent heat of methanol being 1109 KJ/kg, the ultimate steam consumption value for coal-based methanol production is approximately 460 kg per ton of crude methanol
This is also related to the steam quality and the specific type of tower
There will always be some heat loss; it’s only possible to get as close as possible.