Methanol Section Daily Question, April 7: Question regarding the reflux ratio of the pre-distillation column
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Generally, this reflux ratio is quite high (as far as I know, it’s 83). Why is the reflux ratio so high? How should it be considered? This post was last edited by lanseqinghai on 2009-4-7 18:52.]
It’s sufficient to let the light components go out; this principle should be the main consideration. When there are many impurities, consider increasing the reflux to decompose some of the components.
Apart from some vent gas, the pre-distillation column should operate in full reflux; then why do some sources provide values for the reflux ratio? I would appreciate some guidance on this.
Recycling is done to control product quality. The main reasons for defective products are as follows: First, issues with the parameters of crude methanol. Regarding this, there is basically nothing we can do; the only solution is to maintain proper control over the temperature and pressure during synthesis. Second, incomplete pretreatment in the tower. 1. The amount of water added is about 15%, and this is essential – sufficient water ensures complete extraction. When the product quality is poor, adding an appropriate amount helps; beyond 20%, the effect is minimal. 2. If enough alkali is added, the pH at the bottom of the pre-treatment tower can be maintained between 7 and 8, or between 7 and 9 as well – that’s no problem. In addition to providing corrosion protection, alkalis can react with certain insoluble organic substances, which helps in the purification of methanol. 3. Top and bottom temperatures of the tower. If it is too low, the removal of light components will not be complete. 4. The liquid recovered from the exhaust gas treatment unit cannot be discharged directly into the reflux tank; it is better to send it to a separator so that the light components can be removed from the system directly. II. Issues related to the products of the pressure tower: 1. Reflux – this is essentially the only way by which we can control the products of the pressure tower. 2. Temperatures at the top and bottom of the tower. If it’s too high, the heavier components move upward, which is a **problem**! ! III. Products from atmospheric pressure columns 1. Reflux: The amount of reflux determines the temperature; generally, we use reflux as it helps with purification. 2. Side-stream extraction: This is what impressed me the most. Increasing the amount of product extracted does increase the load on the recovery column, but it has only advantages and no disadvantages. More importantly, it is necessary to control the temperature of the material extracted from the side lines, as this allows for the extraction of components that we do not want. Of course, it is first necessary to determine what factors affect the product, identify its relevant physical properties, and then control the temperature in order to extract those components. 3. Temperature: The temperature at the top of the tower must certainly not be allowed to rise too high. As for the bottom of the tower, we prefer it to be higher, as this not only reduces waste but also makes it easier to control the temperature of the side streams. If the steam volume remains constant, the liquid level is the best means of control. Published on: 2009-3-23 21:00
Indeed, such a grand plan just like that! ! It might be the ratio of crude methanol to pre-condenser reflux!
The pre-column should be in full reflux, as no product is extracted from it. Some sources suggest that the reflux ratio for the pre-column refers to the ratio of the reflux volume to the feed volume
The pre-distillation column operates essentially in full reflux mode, but sampling and analysis are carried out in the pre-distillation reflux tank; if it is found that there are many light components, the reflux tank is opened to allow some of these light components to flow into the fusel oil tank. . . . . . in order to reduce the content of light components in the pre-tower
Oh, generally speaking, when the pre-cooling reflux ratio is 0.5-0.8, it refers to the ratio of the reflux volume to the feed volume
The pre-condensation reflux ratio is at full reflux; only a portion of the light components and non-condensable gases are sent to the discharge tank, while the pressure-driven reflux ratio is maintained at around 2:1； The reflux ratio under normal pressure is controlled at around 3:1, with the specific value determined by the load on the tower; as long as the temperature and pressure at the top of the tower remain stable and the distillate meets the required standards, that is sufficient.
We use three-column distillation; the pre-column operates with full reflux, with no methanol being withdrawn. The reflux ratio between the pressure column and the atmospheric pressure column is 2-3
Determined by the load: full reflux in the pre-tower, 2:1 in the pressure tower, 3:1 in the atmospheric tower.
The pre-tower is basically in full reflux mode, while the reflux ratio of the main tower is usually around 2:1
The pre-condensation reflux ratio is at full reflux; only a portion of the light components and non-condensable gases are sent to the discharge tank, while the pressure-driven reflux ratio is maintained at around 2:1； The reflux ratio under normal pressure is controlled at around 3:1
The pre-tower has no reflux ratio! Only the ratio of return fluid to feed rate! What we are controlling is 0.65. There is only one goal! It’s about removing the light components!
The pre-tower operates in full reflux mode, while the pressure tower operates at 2； 1. The atmospheric pressure tower is operated to produce fluid while maintaining the appropriate temperature, pressure, and liquid level.
The pre-tower operates in full reflux; the reflux ratio of the pre-tower is generally defined as the ratio of the amount of reflux in the pre-tower to the amount of feed entering it
The pre-tower operates in full reflux mode, with no product withdrawn. A reflux ratio of 3 to 4 is sufficient for controlling the pressure tower.
In practice, we use temperature to determine whether the pre-tower removal of light components is satisfactory
The pre-cooling reflux ratio refers to the ratio of the reflux volume to the amount of non-condensable gas vented
According to the operating equation for the distillation section, y = r*x/(r+1) + Xd/(r+1); it can be seen that R is related to the purity of the product at the top of the tower. As long as the required product purity is met, a lower value of R results in lower energy consumption.
The correct statement should be: the pre-tower operates in full reflux mode, as no methanol product is extracted from it; only some light components and non-condensable gases are discharged. The pre-condenser reflux ratio generally refers to the ratio of the pre-condenser reflux volume to the feed volume to the pre-column, which is different from the commonly used term \"reflux ratio\"” ； The reflux ratio between the pressurized tower and the atmospheric pressure tower is 2-3. The groove size is determined by factors such as the tower’s load, the amount of qualified products produced, and energy consumption.