Methanol is an important chemical with a wide range of applications. With the advantages of high temperature stability, low volatility and excellent clean energy properties, it is widely used in the production of chemicals, solvents, fuels and fungicides.
Methanol recovery refers to separating and purifying methanol from a mixture or stream containing methanol and other substances. The goal is to obtain a high-purity methanol product.
As a supplier of solvent recovery process equipment, I understand the importance of effective methanol recovery and purification. In this article, I will introduce you to the main products of the methanol recovery and dehydration process and the equipment you can choose for effective methanol recovery and purification.
What Are The Products Of Methanol Dehydration?
- Methanol can be dehydrated to produce dimethyl ether, known as diemethyl ether, abbreviated as DME, which is widely used as a chemical material, aerosol, refrigerant and fuel.
- Dimethyl ether has similar combustion characteristics to LPG and can completely replace LPG as a domestic and industrial fuel.
Dimethyl ether as a fuel alternative has the following characteristics：
- DME has good combustibility and is itself an oxygenated fuel additive with complete combustion, high thermal efficiency of combustion, no carbon precipitation and non-toxic exhaust gas.
- The liquefaction pressure of DME is lower than that of LPG, it can be liquefied at room temperature and stored in LPG storage tanks, which can ensure transportation safety, and at the same time, like LPG, DME can evaporate after decompression at room temperature without preheating, so it can be used immediately after opening, and the burner can be used without major changes.
- DME is safer than LPG as a fuel, its flammability limit is twice that of LPG and the potential for explosion is greatly reduced.
- Since DME itself contains 34.8% oxygen, the theoretical air volume of its combustion process is much lower than that of LPG, while the theoretical calorific value and combustion temperature of the mixture are higher than those of LPG.
2. Methanol to Gasoline (MTG) technology uses methanol as a feedstock and converts methanol vapour to a hydrocarbon mixture (gasoline) below C11 by dehydration, oligomerisation and isomerisation in a catalyst bed at a specified temperature, pressure and air speed.
- The gasoline produced is of excellent quality, free of sulphur and nitrogen, lead-free, residue-free, with low olefin content, long induction time and an octane number of more than 93, which can be used directly as motor fuel with more than 20% more mileage than ordinary gasoline, and can also be used as a high-quality gasoline blending agent.
- By using the countercurrent heat exchange reactor, you can make full use of the reaction heat to preheat the raw gas in the reactor. At the same time, the hot spot temperature inside the reactor is reduced, which improves the reaction efficiency and selectivity, reduces the internal carbonisation of the catalyst, extends the production cycle of the catalyst, reduces the frequency of carbon burning and extends the service life of the catalyst.
- As the temperature rise at the reactor inlet and outlet is reduced, the circulating gas volume is also reduced and the circulation ratio is <5, which significantly reduces the power consumption. Flameout or flying temperature phenomena are less likely to occur during production, and the process is simpler, easier to control and more convenient to start and stop.
3. Methanol can be dehydrated, carbonylated with methyl formate and then synthesised by ammoniation to produce formamide with mature technology and low production cost. The crude product is de-alcoholized, dehydrated and refined under vacuum to obtain the refined formamide product.
- Methyl formate (MF) is a widely used solvent with a low boiling point, such as nitrocellulose, cellulose acetate, etc. It is also a raw material for the synthesis of organic intermediates and pharmaceuticals. Methanol carbonylation is the best production process for methyl formate by hydrolysis of methyl ester formate, and the production cost is only half of the traditional sodium methanol method for formic acid.
- Quality standard of methyl formate: colourless and transparent, MF content≥96%, water content≤0.2%, methanol content≤4.0%, MF content can be increased to more than 98% at users’ request.
Dehydration of methanol is a fundamental process to ensure that the anhydrous methanol produced is suitable for synthesis reaction and further process production.
Here you will find the most advanced equipment for the production of over 98% pure methanol.
How Can Methanol Be Effectively Recovered and Purified?
Methanol can be recovered from different sources, such as natural gas, coal, biomass, and waste streams. The recovery process may vary depending on the source and composition of the feedstock.
High pure methanol is usually produced by the reaction of carbon monoxide and hydrogen, which is volatile and produces a certain amount of water during the production process, resulting in the dissolution of methanol in water, therefore dehydration equipment is required to obtain high purity methanol.
- Distillation Equipment:
Distillation or fractionation is the most common method of methanol recovery. It involves heating the methanol to slightly higher than its boiling point and collecting the vapours, condensing the vapours and obtaining the product. Methanol has a relatively low boiling point (64.7°C or 148.5°F), allowing for its separation from other higher-boiling components.
Super-gravity distillation tower is a new type of distillation equipment that uses the principle of super-gravity technology to enhance the gas-liquid mass transfer process, using the rotating centrifugal force field to replace the conventional gravity field, so that the relative speed of the two phases of gas-liquid is greatly increased, the phase interface is updated faster, and the production intensity is increased exponentially.
Using fold-flow super gravity distillation columns for methanol recovery and separation, feed methanol mass fraction of 60% from the center, and increase the reflux ratio, you can get high purity methanol mass fraction of 99.68%, methanol mass fraction of residual liquid discharge is less than 0.2%, the product discharge volume can be designed according to user requirements.
Super Gravity Distillation equipment replaces traditional column distillation equipment, bringing significant economic benefits to the production of high purity methanol.
| Comparation/Items | Super Gravity Rectification Machine | Packing Type Distillation Tower |
| Diameter/m | 0.8 | 0.6 |
| Equipment Height/m | 0.8 | 12 |
| Volumes/m³ | 0.43 | 3.2 |
| The height ratio of the two units/% | 6.7 | |
| The volume ratio of the two units/% | 13.4 |
A realistic project comparison shows that the super-gravity distillation column for methanol recovery is 6.7% of the height and 13.4% of the volume of a packing distillation column.
Due to the low height and small size of the equipment, it can be easily placed in indoor plants for installation and use, reducing the cost of civil construction, avoiding consideration of lightning, typhoon, rain, snow, earthquake and working at height, as well as increasing the safety of production.
The industrial production performance shows that the separation effect of the Super Gravity Distillation Tower can completely replace the more than 10 metre high packing distillation tower.
It also achieves high efficiency continuous distillation recovery of organic solvents such as formaldehyde, toluene, methylal, ethanol, glycol, acetonitrile, ethyl acetate, acetone, tetrahydrofuran, dimethyl sulfoxide, n-butanol, methylene chloride, silyl ether, cycloethane, isobutane, isopropanol, glacial acetic acid, acetic anhydride, DMF, DMSO, DMAA, DMDA, etc.
The operation of methanol distillation and recovery requires proper guidance, we are able to provide practical operating instructions for operators. Not only the equipment itself has an impact on the process performance, but other connected equipment also has a great stimulus to produce the corresponding chemical reaction.
Different rectification recovery tower is a big difference in material, the internal structure of the change is more beneficial to the play of the equipment itself.
2. Molecular Sieves Membrane Pervaporation Equipment
Molecular sieves are a type of desiccant that can be used to remove water from methanol. The process involves passing methanol through a bed of molecular sieves which selectively adsorb water molecules. The resulting anhydrous methanol can then be collected. This is easy to achieve with laboratory scale equipment.
However, for pilot and industrial scale solvent dehydration and production lines, we recommend the use of pervaporation zeolites membrane dehydration units, which provide highly efficient automatic control of process operations.
The pervaporation process consists mainly of raw material preheating, inorganic molecular sieve membrane separation, vacuum suction and product condensation.
Water is a common impurity in methanol, and its removal is crucial to ensure the quality and stability of the final product. We can design applicable assembly unit of pervaporation process according to your process requirements and capacity.
The dehydration system can be properly modularised to integrate with other chemical processes, such as methanol synthesis or downstream applications, to optimize overall efficiency and resource utilization.
The membrane permeation is measured by vacuum plus condensation to create a partial pressure difference of vapour, and the permeate vapour enters the condenser under vacuum suction to be condensed and recovered for processing.
The process is simple and requires precise control of operating conditions and a stable utility supply system.
What Do You Need To Know About Methanol Recovery?
- Monitoring the purity of the methanol:
It is important to monitor the purity of the methanol throughout the recovery process. This can be done using a refractometer or a gas chromatograph. High purity methanol is essential for certain applications, such as biodiesel production.
- Dispose of waste properly:
The recovery process produces waste products such as water and contaminants. It is important that these waste products are properly disposed of in accordance with local regulations.
- Store methanol properly:
Methanol is a highly flammable liquid and should be stored in a cool, dry and well ventilated area. It should be kept away from heat sources and naked flames.
- Regulatory standards and guidelines may exist for methanol recovery and purification processes to ensure compliance with environmental regulations and product quality requirements.
Conclusion
Methanol is a basic chemical raw material, the production process equipment has been improved to achieve energy saving and consumption reduction, high efficiency and environmental protection production features.
Effective recovery and purification of methanol is essential for many industries, including the chemical, pharmaceutical and energy sectors. By following the optimized process flow and using advanced process equipment and technology, you can ensure that you recover and purify methanol effectively and produce high quality anhydrous methanol suitable for your specific application.
At present, the world is advocating the concept of green environmental protection and low-carbon lifestyle. The activity of transforming methanol into green fuel, green solvent and other green energy in the future has infinite potential for development, especially the direction of vehicle fuel will be an effective initiative to change the energy industry landscape.
Hope this article will be helpful to your business, if you need any further technical or commercial disucssion, please contact us freely.
