Chemical and Biomolecular Engineering

Official blog of the Lehigh University Chemical Engineers

Leave a comment

Guest Speaker Keith Krenz

Last Friday, it has been such a pleasure to have Mr. Keith Krenz as our guest speaker. He had quite an impressive resume and he has involved himself in many business areas. He founded his engineering research company in 1985. He has then succeed himself out of the company by 2004, and has been working on special projects internationally. He began his speech by discussing some underlying leadership principles and core elements. For example, leadership is critical in the amount of experience, consistency and confidence. I really liked this quote his presented from Alice in Wonderland, “If you don’t know where you are going, any road will take you there!” I think it makes a lot of sense and it applies to me well. As a graduating senior in college, I constantly have to figure out what I want to do after college. The answer is not always clear. However, I realize that I must do something so I get somewhere. This quote explained it very well.

One of the most important thing I learned that a company must keep up with the business trend. As the leader of the company, you have to decide whether you want to take a risk and make a new product, or sticking with your current product and see how much that’s going to cost you. When you start to lose too much for not changing, maybe then it’s time to create new product ideas. Keith gave some excellent examples of this concept. It made a lot of sense too because if McDonalds’ has a new type of milkshake, then Wendy’s need to create something just like that to not lose customers and keep up with the market.

The presentation can possibly be more effective is that less flow chart could be used. I thought that the flow sheet a little confusing to follow. Also, I thought there’s too much word being used in the slides, which made the presentation hard to focus. It’s also difficult to read everything that’s on the slides. In addition, I would be very interested to hear his suggestions on what I should do now to get myself closer to become a great leader like he is. A great leader is not made in one day. I think it will be a great idea to hear things I can do along the process of changing myself from a team member to a team leader.

Leave a comment

Pilot Plant Distillation Column Experiment Part 2

Now let me take you to the the actual place where this experiment was carried out (hashtag no filter).

FullSizeRenderAs you can see here, my lab partner is monitoring the controls and trying to keep the column profile constant. From that white panel, you can turn the feed, bottom pumps on and off. You can also adjust the valve positions for feed, steam, reflux, distillate, and bottoms valves. Tank level and flow rate information was then sent back to the top two rows of the panel. Above that, there is a nice little black and white TV screen to see the methanol being condensed back down on top of the column. In this picture the thing that’s going through the ceiling the actual distillation column. To its left back side are the holding tanks for reflux, bottoms, and overhead. The steam and cooling water valves are located towards the backside of the wall.

One of the things wed had to do (also most exciting part of this experiment), was blowing down the steam through the pipe. And fortunately I have a short clip to share with you this moment.

Due to time constraint, we were only be to do two steady state runs, and they are total and partial reflux runs both with feed stream at stage 4. Samples were taken for the feed, overhead, and bottoms stream, and there compositions were analyzed by GC. Temperature information was automatic saved from the computer. Flow rates were measured by the bucket-n’-stopwatch method. Once we have them then we’re ready to do some calculations!

Leave a comment

Pilot Plant Distillation Column Experiment Part 1

This Friday my partner and I concluded the lab session on a 8-inch Pilot Plant Distillation Column. This lab is particularly exciting for its level of complexity and how well it models an actual plant. I would personally rate this as probably my favorite experiment of all Unit Ops experiments. It’s a nice refresher on the material that we had learned from Mass Transfer class. The distillation column just made much more sense to me after this experiment.

In this experiment we analyzed a pilot-scale distillation column for a binary mixture separation under steady-state conditions. A binary mixture of methanol and water is to be separated by feeding it through a distillation column of 8 inches in diameter and 14 valve trays. Based on my lab partner and my calculations. The feed was to be introduced to the column at tray number 4. Steam, cooling water, feed, reflux, distillate, and bottoms product flowrates are being measured with orifice meters. The compositions in terms of mole fractions can be checked by Gas Chromatography at three stream locations (Feed, Overhed, Bottoms). Heat losses from the reboiler, the column and the condensers can be calculated from the measured compositions and flowrates at different locations. Subsequently, the overall and Murphree tray efficiencies can be calculated from the change in heat in the system. A combinations of reflux ratios and feed flow rates was supposed to be implemented and the results from that will be used to further investigate column behavior. One thing to keep in mind that the mass and energy balance will not be totally balance due to the fact that it is not an ideal system. Heat tends to get lost moving along different sections of the column.

Here’s a scheme of the Distillation Column. As you can see, the red dotted lines are the control signals for reading the levels, flow rates, temperatures, and pressure at various locations of the column. They were then used to adjust the valves to maintain steady state.

column scheme

Basically, a binary mixture of methanol and water is first pumped from the feed tank through a feed preheater into the distillation column at tray #4. The feed preheater uses the overhead vapor from the column as a source of heat. Overhead vapor is then condensed and subcooled in a series of heat exchangers. One of the heat exchangers is used to preheat the feed, the other two are condensers that being cooled by water. The condensed vapor is then sent to the reflux drum, where part of the liquid methanol is pumped out as the product, and rest is sent back as reflux. The product is sent to a holding tank, the reflux is sent back into the column at the top tray. The vapor boil-up is provided by a steam from thermos-syphon reboiler. The bottoms product is withdrawn through a cooler and pumped to the bottoms hold tank

One way to determine the overall column efficiency is by using the McCabe-Thiele Diagram, under the assumption that efficiency is the same on all trays and in the partial reboiler. We have used the McCabe-Thiele method to determine the number of ideal stages and feed tray location. Parameters such as the mole fractions of methanol at the distillate, bottoms, and feed, as well as the reflux ratio were used to perform the calculations. A plot including the equilibrium curve, feed line, and operating lines for the rectifying and stripping sections are constructed. The number of stages was then found by using the stepping method starting from the either the distillate or bottoms composition on the operating line. The Murphree tray efficiency was determined similarly. However, an effective equilibrium curve was used instead of the ideal equilibrium curved used in overall efficiency calculations.

Leave a comment

Resources Beyond the Textbook

Let’s face it, sometimes you have a professor that you don’t love or the textbook explanation doesn’t quite do it for you. In these cases, it’s not like the world stops. The assignment is still due, the test is still tomorrow, office hours have past, so what can you possibly do to learn the material?

There are a few solutions that I can propose.

1. Phone a friend. This could be an easy fix if you understand the general concept but there is a specific problem or issue you are struggling with. If you are super lost, you’re friend is most likely going to be annoyed and you aren’t going to learn anything.

2. Ask your TA. You’re TA is a better resource for large conceptual issues you’re having, however, they don’t have all the time in the world to sit down and ensure you understand it, so it’s imperative you give them your undivided attention when you do get a chance to sit down with them.

3. Google it. This is almost too simple, but some of the most affective tutoring I have received is from good, old Google. My favorite thing to do is to watch 5-10 minute youtube video explanations. They cover the one topic I am having issues with in a clear, concise way with an example to finish it off. Nine times out of ten, I come out with a better understanding of the topic.

4. Sit down with your Professor and talk it out. If you are really struggling and none of the above have worked, it’s time you had some one-on-one time with your professor to ask for extra resources, problems, etc. to see if it will help you. You could also take this time to ask if they know of anyone willing to tutor for the specific class, and usually they do.

The resources are definitely available, but you just have to be willing to put in the extra effort to find it! And remember, it’s almost Friday!

Leave a comment

It’s the Little Things

So I know for the most part this blog is supposed to be super science-y and specifically about chemical engineering, but me being the true rebel that I am am diverging a bit to talk about becoming the best version of yourself. I hate to break it to you, but college is just as stressful as it is fun. Sure you have a ton more free-time than in high school, but if you misuse that free time, you’re behind in a class. Sure you only have two tests per class per semester, but if you bomb one, you can count on getting a low grade for the semester. Sure there are fun things to do all the time, but if you don’t sleep you’ll get burnt out. Each one of these things has a domino affect on your life.

While that is a bit scary to think about, if you mess up the only thing you can do is try one day at a time to get back to where you need and want to be. I’d like to think I finally have college figured out. Go to office hours, study a little every day, try to be healthy, etc, But once midterms come around or you get into a fight with your friend, it’s hard to stay focused on what is the most important, which is getting an education that lays the foundation for the literal rest of your life. So the next time you diverge from what you think you should be doing, take a moment to breathe and re-evaluate, because soon enough you will be back on track.

For me, I finally got my schedule down with school and work, so something I wanted to work on is going to the gym more. College is really all a balance. To keep everything in check, when you want to add something, you may need to take away something else. For the past week, I started going to the gym every day, which is about an hour and a half time commitment. Because of this, I gave up watching an episode or two on netflix. This was a personal win on my part because not only am I no longer watching netflix, I am using that time for something much more productive. Furthermore, it has become a part of my daily routine and hopefully will stay that way,

You might think going to the gym isn’t really a huge deal, but it’s the small changes that you keep adding that will eventually get you to the place you want to be. My next step is removing coffee from my daily life. Just to prove how difficult this is going to be, I haven’t had any for one day and I already have a headache. If I can make it the rest of the day without caffeine, that will be another personal win, but if I give in, I can try again tomorrow. As long as you’re willing to keep putting in the effort, you can always improve yourself.

Oh and before I go, my dad just texted me this joke:

What do you do with chemists when they die?

You barium.

Have a good week engineering friends!

Leave a comment

Strategies and Tips to Distillation Column Control

41KWuHvo9NL._SY344_BO1,204,203,200_This book written by one of the most pretigious Lehigh Chemical Engineering professor Bill Luyben is like the Holy Bible to distillation column control. It’s colloquially known as “the blue book”, and it’s been read and passed on from hands to hands. Similarly to its infamous brother, “the yellow book” which was used in the first semester in process design, it covers a ton of detail and everything you can learn so much from going through page to page. Here I would like to share with you some insights on distillation column controls strategies.

There’re tons of distillation column control schemes out there. It’s very hard to decide which control scheme to use, especially choosing the ones that works with your column and ones that work correctly. Most importantly, you must choose what you like to control to meet your control objectives. For my project, I have to ensure the product meets a certain required purity, and certain required vapor distillate flow rate. My process can be considered a binary process because the main components in this separation processes are Ethylene Oxide and water.

Generally, an effective operation of a distillation column needs to consider the control of the following variables:

  • Composition of the distillate stream, xD to ensure product quality
  • Composition of the bottoms stream, xB to also ensure product quality
  • Liquid level in the condenser reflux drum to maintain inventory and satisfy material balance
  • Liquid level in the sump to also maintain inventory and satisfy material balance
  • Column pressure to ensure equilibrium.

These variable should always be controlled in a distillation column. However, how you want these to be controlled is up to you. However, there’s a few rules that applies to most cases. For example, it’s always a good idea to flow control the smallest product flow. In my process there is a relative small distillate flow rate in comparison to a large bottoms flow rate. The material balance must satisfy around the condenser drum. In order to make sure the liquid level remains constant, a level controller must be used in the reflux drum. For the same reason, a level controller is required on the sump with the manipulated variable being the bottoms flow rate.

It’ll make a lot of sense to use a energy balance control scheme when there’s a small reflux ratio. If the reflux rate is small in comparison to the distillate rate, then a relatively small change in the distillate rate will ensure a good condenser level control. To control the composition of the product, a on-line composition control is not often used because it’s very expensive and unreliable. One typical way to do this is to control the temperature of the stripping section of the column.

Fortunately, my column falls into one the standard categories, which has made it easier to choose from. However, right now it’s still in progress. I’ll upload it once it’s finished and ready.

Leave a comment

Guest Speaker Dr. Ray Glemser

For my Leadership Development class we always invite guest leaders to come in and share their life experience with us. And we were very fortunate to have Dr. Ray Glemser to come to Lehigh University as a guest speaker.

glemserlogo-mediumRay Glemser is currently the CEO of Glemser Technologies. Glemser Technologies is a leader in the design, development and implementation of content management solutions for life sciences companies. It provides IT solution to especially pharmaceutical business processes. Their office is in North side Bethlehem across from the Lehigh campus. It’s interesting to realize that his wife was my former landlord at the off campus house I used to live in. And the professor of this class is the landlord of the off campus house my friend lives in.

Ray is a Lehigh alum. He received his doctoral’s degree in 3D tolerance analysis from Lehigh Univeristy. While he is in graduate school here, Prof. Emory Zimmers was his mentor. Ray has learned quite a lot from his mentor, including leadership styles and life philosophies. He began his presentation by providing us a review of his life events including the times he was at Lehigh. There are three things that made him special and stand out from the other. The three traits are that he worked harder and longer than the others; he kept himself interested and motivated by surrounding himself with the right people and keeping up with schedules. He was able smart enough to see patterns in what he was doing and he was able to learn quicker than the others.

One of the most important pieces of advice that Ray gave was that never bring family into the business. Ray learnt that when family members were brought into the business, the business dynamics will become very unstable. If the leader tried to keep things straight business, then family relations will suffer. This is because family members tend to develop a sense of entitlement that other normal employees don’t have. Therefore, families must stay out of the business. Also, the case study was very effective because all three cases were very challenging and interesting.

The presentation could be more meaningful if Ray had given more stories on how he was able to manage to never work for anybody in his career. It might be his natural ability to lead others because he is very knowledgeable in what he does. I would be very interested to hear his suggestions on what I should do now to get myself closer to become a great leader like he is. Last, I like how he said one should dress like a leader. I thought he was very well dressed and tailored in his suit.


Get every new post delivered to your Inbox.