Talk about the production process of dimethyl ether
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The composite acid method does not suffer from corrosion issues due to the use of reactive distillation; the main challenge is controlling the process parameters. Its advantage is that there is little non-condensable gas, and it is easy to achieve a purity of 99.95%. The solid acid method requires a higher reaction temperature than the liquid composite acid method, which leads to more non-condensable gas being produced, but it offers a larger capacity per tower. Each of these two processes has its own advantages and disadvantages. I have experience with both processes: for composite acids, the volume ranges from 1,000 to 5,000 tons, while for solid acids, it ranges from 10,000 to 50,000 tons. I have not implemented the one-step syngas process; theoretically it is a viable approach, but industrialization is still some time away. I believe there is still work to be done in the existing processes to make full use of the reaction heat to optimize them.
I just don’t understand how the complex acid method can result in no corrosion, and why there is no acidic wastewater generated Please give your advice
Similar to the view from above, I’m not quite sure either. Moreover, most composite acid processes take place at low pressures, making it difficult to scale them up. If the pressure is increased, acid will be generated, causing equipment corrosion
If the water produced and the remaining methanol are vaporized inside a reactor, and since methanol has a much lower boiling point than water, a large amount of methanol will be vaporized; as a result, the circulation rate of methanol would be extremely high!
In response to the questions from friends on the second and third floors, the liquid composite acid is not a sulfuric acid-based substance; moreover, thanks to reactive distillation and process control, the gas coming out of the tower contains no acidic substances.
:o I’m interested. Could you explain the reasons for cracks and leaks around the flanges of fiberglass-reinforced plastic pipes? How should I deal with this?
The so-called composite acid is a mixture of sulfuric acid and phosphoric acid; it breaks the azeotropy between sulfuric acid and water, thereby reducing the amount of sulfuric acid that is carried away. However, corrosion of the reaction vessel still occurs. It’s not clear what type of reactor is being used
In reply to the friend on the 7th floor: Sulfuric acid and water have only one boiling point, which is 326°C. Have you studied the processes used by Shanghai Petrochemical Institute, Shandong Qingzhou for the production of dimethyl ether, Jiu Tai for dimethyl ether production, as well as many small factories in Jiangsu for manufacturing dimethyl ether?
The process flow for synthesizing dimethyl ether from methanol using the liquid-phase method: http://www.chunmijishu.com/html/erjiamijishu/erjiamishengchangongyi/20090116/437.html. Actually, there’s nothing that’s hard to understand; all of the issues mentioned can certainly be resolved. Otherwise, Jutai wouldn’t have been able to expand its operations on multiple occasions.
Shandong Jiutai Company uses the liquid-phase dehydration method, which effectively solves the problem of liquid-phase corrosion, and has become the world’s largest producer of dimethyl ether. I think the liquid-phase method is better, though there are core technical issues. The liquid-phase production process holds great potential and value.
What is the sulfuric acid concentration? I heard that sulfuric acid is mixed with nitric acid; what is the operating temperature? What is the pressure?