The instruments and equipment used for catalyst preparation have been installed, and the preparation work of a group is basically ready. It only needs some debugging before the work can be officially started.
Catalyst preparation mostly relies on manual operations, but its process indicators are controlled by instruments and equipment. Due to the limitations of the conditions at the time, for example, the crushing and sieving of activated carbon could only be carried out in a batch operation equipment, and the impregnation of palladium salts required very careful manual operations, which required a lot of proficiency of the operators. And responsibility is a test.
During the debugging of the equipment, Fang Hanmin went to a group to check the work progress and saw that Jiao Tiehui was practicing the crushing and screening of activated carbon in special equipment under the guidance of Jiang Guoxin, and the other two workers were practicing the impregnation of palladium salt solution under the guidance of Wan Cheng.
Nominally, two technicians, Jiang Guoxin and Wan Cheng, guided the workers' operations. In fact, their operating level was not much better than that of the workers. Seeing Fang Hanmin observing from the side, Wan Cheng, who also came from level 79, might be working with the second level in private. Guo Peng had some tacit understanding with Fang Hanmin. Guo Peng tested Fang Hanmin's theoretical level. Wan Cheng wanted to test Fang Hanmin's hands-on ability. He took the initiative to turn around and greet Fang Hanmin, "Chief Fang, do you think we are a little clumsy?"
"Everything is difficult at the beginning, and it's the same for everyone. After a long time of operation, you will naturally become proficient."
"I heard that Section Chief Fang used to conduct experiments in large-scale equipment. I think the laboratory operations should be better. This is our first time. I wonder if Section Chief Fang can give us a demonstration?"
In his previous life, Fang Hanmin completed his doctoral thesis in pharmaceutical science in a famous laboratory at the University of Oxford. After joining the workforce, he worked as a project manager at the New Drug Creation Center of RGP Company. In addition to weekends and holidays, he spent time in the laboratory every day. Compared with the cutting-edge biochemistry experiments he did at that time, the crushing and sieving of activated carbon and the impregnation of palladium salt solution were not difficult for him at all.
Fang Hanmin didn't think much about it. He felt that it was appropriate to give a demonstration. "No problem, but when you talk, it's best to save Chief Fang and talk about something when you have something to say."
"I'm not wrong. You are the section chief. Is there anything wrong with that?"
"There's nothing wrong, I just think it doesn't sound right to my ears. Why don't I call him by his first name?"
Fang Hanmin walked to the test bench and took the utensils and tools from the operators. Whether it was dissolving, stirring, solution transfer, or filtering and washing, he did it very skillfully without wasting a drop of solution. This needs to be paid attention to, because Palladium is a metal more precious than gold. Even a little waste will cause obvious losses.
It took nearly two hours to complete the entire operation from beginning to end. During this period, Fang Hanmin concentrated on the work at hand and did every step meticulously. Everyone present was fascinated. Near the end, an operator I couldn't help but admire, "Chief Fang, I didn't expect you to have such a skill!"
An operator next to him who also came from the acylchemical section of the second workshop immediately corrected him, "Section Chief Fang has more than just one hand. He has many hands. In the past few years, have we seen less of him?"
Wan Cheng and Xu Hui also nodded frequently, "This operation method is so professional! It is simply the professional among professionals!"
Putting down the equipment at hand, Fang Hanmin showed a weird smile, then turned around and asked, "Are my operating techniques professional?"
"Chief Fang, I didn't expect that your basic laboratory skills are so good. Not only are your movements very standardized, but you are also very rigorous. To put it bluntly, those of us who have received professional training are too far behind you!"
"Professional training? Hahaha!" Fang Hanmin only knew what he meant.
After washing his hands, Fang Hanmin was about to leave, but Wan Cheng stopped him again, "Fang, Section Chief Fang, I have another question to ask you."
"Please speak! As we just agreed, we are only discussing here, not asking for advice."
"Activated carbon itself is a porous material and can be used directly. Why do we need to grind it into ultra-fine powder?"
"When I was discussing the issue with Guo Peng yesterday, I mentioned a technical term called specific surface area. Ordinary activated carbon is indeed a porous material, but its specific surface area is not large enough. If it is ground to a certain fineness, the specific surface area can be larger. The amplitude increases. The specific surface area is one of the most important performance indicators of the catalyst, and the purpose of grinding is to maximize this indicator." Fang Hanmin explained.
"According to the relevant definition, the smaller the particle size, the greater the specific surface area. Should we pursue smaller grinding fineness?"
"This is theoretically true, but test results show that when the particle size is small to a certain extent, the increase in specific surface area is not very obvious. Even if the specific surface area increases as the particle size further decreases, the processing difficulty becomes even more significant. Increase, because the processing difficulty is not directly proportional to the increase in specific surface area, in actual work people do not pursue minimizing the particle size of activated carbon."...
According to the test conditions given by Fang Hanmin, within half a month, the first group prepared the first batch of palladium-carbon catalysts. After aging treatment, they could be used for the hydrogenation reduction test of p-nitrophenol, also called palladium-carbon catalysts. Catalyst evaluation.
The preparation process has a great impact on the performance of the catalyst, but the aging treatment is crucial to the activity and service life of the catalyst. During the aging test, Xu Hui and Wan Cheng had doubts about the process conditions given by Fang Hanmin, "Why The aging temperature must be 300°C and the time must be 24 hours? It’s all testing anyway, so why can’t it be tried at 250°C, 280°C or 320°C? Why can’t the aging time be 15 hours, 20 hours or 30 hours?”
After hearing the doubts of the two technicians, Fang Hanmin not only had no other ideas, but believed that it was worth encouraging the technicians to dare to ask questions. Because the catalyst is relatively expensive and cannot tolerate more waste, Fang Hanmin only gave two other sets of aging test conditions, namely 280°C, 30 hours and 320°C, 20 hours.
In order to distinguish the catalysts under the three sets of test conditions, Fang Hanmin marked the 300°C, 24-hour aging conditions he gave as the first batch, and the catalysts under the other two sets of aging conditions as the second and third batches respectively. batch.
After preparing the first batch of catalysts, the second group of catalytic hydrogenation test equipment is ready. According to Fang Hanmin's suggestion, they first need to evaluate the first batch of palladium-carbon catalysts.
According to the test conditions given by Fang Hanmin, the second group used the first batch of catalysts to conduct a hydrogenation reduction reaction. Six hours later, the evaluation test was completed. Through laboratory analysis and testing, the selectivity of the catalyst to the target product reached 99.5%, and the conversion rate was 99.5%. 62%.
The evaluation test continued and the reaction time was extended. The selectivity of the catalyst remained basically unchanged and the improvement in conversion rate was very limited. Shortening the reaction time had basically no effect on the selectivity of the catalyst, but the conversion rate dropped rapidly to 55%.
A week later, one group completed the preparation and aging of the second batch of palladium-carbon catalysts. The second group conducted an evaluation test under the same conditions. As a result, the selectivity of this batch of catalysts reached a maximum of 98.5%, while the conversion rate was only 50%. about.
The evaluation test of the third batch of palladium-on-carbon catalysts was completed one month later. The data showed that the best selectivity result was only 97% and the conversion rate was 55%.
The data does not lie. Three batches of palladium-carbon catalysts were prepared according to different conditions. Only the first set of process conditions given by Fang Hanmin produced the best catalysts in terms of selectivity and conversion rate. The other two sets of process conditions, Obviously not the first choice for preparing palladium on carbon catalysts.
The scientific research team led by Fang Hanmin spent less than half a year, from catalyst preparation to efficiency evaluation, to complete a small-scale study on the preparation of acetaminophen by hydrogenation reduction method. He is going to make a summary of the laboratory work during this period, and then Move to the next stage of intermediate amplification testing.
After receiving the arrangement of the work summary, Jiang Guoxin and other four technical staff found it incredible. In their impression, the technical development of this kind of project, even if small experiments are done in the laboratory, it would be impossible to complete the project within two or three years. Fang Hanmin wanted to finish the question in such a short time. Was it too hasty?
The four technicians compared Fang Hanmin's decision with their experiences in college. They doubted whether Fang Hanmin understood the general process of scientific research work.
"Chief Fang, is this the end of the small test?"
"Yes, the work in the laboratory is basically over. Next we have to prepare for the pilot scale-up test."
"However, it has only been three or four months, and we have only done comparative experiments on three sets of process conditions. Isn't it a bit too rigorous to end the small test like this?" The four technicians, represented by Guo Peng, spoke very Straightforward.
Fang Hanmin doesn't like to beat around the bush, and he is very comfortable with this straightforward way of speaking, "Oh, do you think the pilot test was not rigorous? Okay, everyone, come to my office, let's discuss it in detail. I want to know what aspects were not rigorous. .”
Fang Hanmin temporarily borrowed some chairs from other offices, and sat around with four technicians. He wanted to create an atmosphere of intimate conversation, "Which of you four will talk about the previous stage of laboratory work first? What aspects have we not done carefully enough?”
Guo Peng took the lead, "While in college, we also did some research and development of scientific research projects with our teachers. Although we were just assistants, we also knew the general technology development process. In the previous experiments, regardless of the preparation of palladium carbon catalyst , or for performance evaluation, we have just tested three different sets of process conditions, and I think they are too few, a bit random, and too imprecise."
"I agree with Guo Peng. It is too hasty to end the small trial project in such a short time! It should take two or three years to test various possible process conditions. Even if other process conditions are not feasible, they should be verified through experiments. It's also convincing." Wan Cheng then echoed that he and Guo Peng did have a tacit understanding.
Fang Hanmin did not comment for the time being. He looked at Xu Hui, who was at level 77, and Jiang Guoxin, who was at level 78, and said, "Two eldest brothers, please share your opinions."
"Similar to them, we have similar views."
Fang Hanmin nodded, "The comments are very good, but they feel a bit general. I wonder if you can make things more specific?"
Wan Cheng seems to have been prepared, "For example, I think that in the preparation process of the catalyst, we should further test different particle sizes of activated carbon, and the catalysts obtained by impregnating palladium salt solutions with different concentrations will have different catalytic performance under different activation conditions. .”
"The different effects of catalysts prepared according to different process conditions on the hydrogenation reaction under different hydrogenation process conditions also need to be verified through multiple batches of experiments. This work cannot be completed in less than two years." Guo Peng and Wan Cheng sang together.
From the speeches of the two peers, all Fang Hanmin saw was their sense of responsibility, and he was pleased with this. This was always much better than the muddled work attitude!
However, Fang Hanmin had no intention of slowly conducting experiments in the laboratory in order to form a scientific research team for the in-depth technical transformation project of the second workshop.
