Problem with heating the material in the reactor?
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The power plant supplies 10 kg of steam at a pressure of 250 degrees, which is used to heat the material inside and outside the coiled tubes of the 18 cubic meter reactor to 240 degrees; the reactor is equipped with a stirring mechanism. First, can this pressure be heated to 240 degrees? Second, if it’s possible to estimate how much time is required, how can we raise the temperature of the materials to 240 degrees as quickly as possible?
This requires process engineers to conduct a thorough energy balance analysis in order to draw conclusions – as to what the materials are, what their properties are and what other relevant parameters exist, as well as how much of these materials there is; none of this information is available!
It is an esterification reactor; the raw materials are octanol and terephthalic acid, with a total amount of material of around 15 T.
For 10 bar steam, if it is saturated steam, the maximum temperature can reach 184 degrees; it cannot reach 250 degrees. In addition, losses in the pipes must also be taken into account. Unless superheated steam is used. I think for mixing equipment, it’s better to have the heating steam temperature at least 30 degrees higher than the temperature required by the material. In other words, the steam temperature should ideally be 270 degrees or even 300 degrees. As for the heating time, it can be roughly estimated. I just don’t know what the proportion of your materials is. Once that proportion is known, ASPEN can be used to simulate the material properties, which will then allow us to obtain the data needed for heat transfer calculations. Thermal transfer calculations for mixing equipment are quite complicated; different mixers have varying thermal transfer efficiencies, which means that the formulas used for such calculations also differ. In your case, I think a total thermal transfer coefficient of 300 would be appropriate, as it represents a more conservative value. Also, I think heat transfer oil can be used for heating; steam is too unpleasant.
Thank you for the answer from above. The material ratio is terephthalic acid: octanol = 1:1.2. The reaction vessel is made of stainless steel. Who would use ASPEN to do the calculations?
Use ASPEN to obtain the specific heat capacity of the material, and then calculate it using equation 5-3 from the book \"Stirring Equipment\".
Is steam at 10 at saturated steam or superheated steam? The temperature of saturated steam at 10 at is only 183 degrees, which is not high enough to reach the desired temperature； It is recommended to use heat transfer oil, as this is a more reliable option. For the grade of heat transfer oil, choose one designed for high temperatures of 350 degrees, so that the temperature of the hot oil can be kept at a sufficiently high level, thereby increasing the temperature difference for heat transfer with the material. It is estimated that it will take a considerable amount of time to raise the temperature of a 18 m3 reactor to the desired level; therefore, if you want to reduce the heating time, it is necessary to increase the heat transfer area. It is best to use a heater with external circulation, as this significantly increases the heat exchange area.