Majari Picks: Web-of-the-Month is American Institute of Chemical Engineers

Today, if you’re thinking about a Chemical Engineering professional organization, the word AIChE should pop up on your mind. As far as I know, AIChe is the world’s leading organization for chemical engineering professionals. The only institution run by chemical engineers for chemical engineers. Founded in 1908 with more than 40,000 members from 93 countries until now.

As a member, we can access information on recognized and promising chemical engineering processes and methods through knowledge gained from AIChE’s eLibrary. Connecting with a global network of intelligent, resourceful colleagues and their shared wisdom. Find learning opportunities from recognized authorities. We can also views their latest chemical engineering news on CEP publication.

Unfortunately, some of AIChe benefits like scholarships, awards and competitions, conference and events, are only eligible for US citizen. But tools, career resources, eLibrary and more are online worldwide available.

And favorite options from AIChe is their FREE member registration for both, students and professionals.

See you again later on Majari Picks!
Salam Majari Kanayakan.

Try to google the stuff with the name of the software followed by the keyword ‘free download’ and click the search button. Find the related site of the software and click the download link. Follow the instruction to install it on your PC. Enjoy searching!! Hunting softwares itself is a fun thing.

The Chemical Kinetics Simulator (CKS) provides a rapid, interactive method to simulate chemical reaction mechanisms. It only requires basic information: the reaction mechanism and kinetics, initial concentrations, reactions conditions and several simulator setup parameters. Once a simulation is complete, you may select the types of data plots to display. The choices are concentration, temperature, pressure, and volume vs time or concentration, pressure, and volume vs temperature. (Freeware)

ChemEng Economics Calculator was mainly created to do the basic estimation of the Net Present Value of a chemical plant. This easy-to-use software also includes calculators such as estimation of total plant cost – overall basis, exponential estimation, updating estimates, and estimating total plant cost from individual cost sections. (Demo)

Est$Pro was developed to serve a specific purpose, rapid conceptual cost estimating of process plants and equipment. It will estimate process equipment prices and also estimate the cost of purchasing and installing bulk materials that user defines. (Demo)

Basic Acid Titration and Equilibria – BATE is a program for pH calculations in mixtures of acids and bases, weak and strong, with or without ionic strength. BATE is able to calculate pH of any mixture of acid and base faster then you will be copying the results from the screen. Whether you need to prepare a solution, or examples for lecture, or you want to check your homework – BATE is as handy as possible (Demo)

ACDLabs 10.0 contains of three programs i.e ChemsSketch, 3D viewer, and ChemBasic. ACD/ChemSketch is the powerful all-purpose chemical drawing and graphics package from ACD/Labs developed to help chemists quickly and easily draw molecules, reactions, and schematic diagrams, calculate chemical properties, and design professional reports and presentations. ACD/3D Viewer is a fast yet accurate 3D modeling and visualization program. It is fully integrated with ACD/ChemSketch, allowing you to draw 2D structures and quickly obtain their 3D representations in a striking 16 color display. ChemBasic is a simple, convenient and functionally rich programming language for the presentation and manipulation of molecular structure, related objects and all the content of ACD/Labs’ current and future programs. ChemBasic is founded on, and fully integrated with, ACD/Labs existing functionality. At the same time, ChemBasic has all the things a programming language should have: numeric and string variables, arrays, flow control and conditional operators, input/output procedures, etc. (Freeware for educational purpose only)

ChemLab comes with a range of pre-designed lab experiments for general chemistry at the high school and college level. Users can expand upon the original lab set using ChemLab’s LabWizard development tools, thus allowing for curriculum specific lab simulation development by educators. These user designed simulations combine both text based instructions and the simulation into a single distributable file. (Shareware)

Discounted Cash Flow Analysis Calculator is a capital budgeting and investment analysis tools which simultaneously evaluates 14 cash flow series comparing 5 different discount rates (or costs of capital) per series. For each series (or capital budgeting project) Discounted Cash Flow Analysis Calculator provides the following results: Initial Investment, Smallest Cash Flow, Largest Cash Flow, Cash Flow Range, Average Cash Flow, Number of Cash Flows, Undiscounted Sum of Cash Flows, Internal Rate of Return (IRR) and Undiscounted Payback Period. (Demo)

PackCol performs hydraulic design for new packed columns or rating calculations for existing columns and towers. The design basis can be approach to flood, maximum capacity or pressure drop. Includes a database of packing types, but custom data can be used. The Eckert and Robbins correlations are included to cover the full flow rate range. Results can be printed in tabular form, and plotted as a Generalised Pressure Drop Correlation diagram or as an Operating Diagram. Detailed manual and tutorial included in Word v6 format. (Demo)

Enjoy the software. Remember, piracy is a crime. Never try to find cracks to illegally get the fully functional version of the software. If you find the software helpful, consider buying the license. If you cannot afford it, please use sharewares and freewares only. We all agree on using inexpensive ways to be smart, but it has to be legal, as well.

Punya pertanyaan tentang kuliah? Isu hangat Teknik Kimia? Ditemani secangkir kopi hangat, Ask Majari akan mencoba membantu kamu. Semangat! Tiap masalah pasti ada solusinya!

Hai Majari Kanayakan,

Salam,
Vero.

Hai Vero,
Terima kasih banget atas interest-nya terhadap website ini. Semoga website ini dapat benar-benar bermanfaat dan dimanfaatkan oleh seluruh mahasiswa Teknik Kimia se-Indonesia. Jangan pernah lupa buka Majari ya! Hehehe..

Mengenai software, sepertinya hal tersebut memang terjadi di sebagian mahasiswa Teknik Kimia. Ada hal yang perlu digarisbawahi dalam pemahaman software komputer. Pemahaman itu terdiri dari dua bagian: (1) pemahaman konsep, dan (2) pemahaman teknik pengoperasian. Nah, dari kedua pemahaman tersebut, manakah yang paling penting?

Sebagai mahasiswa Teknik Kimia, kita menggunakan software sebagai alat bantu perhitungan, simulasi, dan pemodelan. Sebagai mahasiswa semester 8, Vero pasti sudah tahu benar bahwa perhitungan Teknik Kimia relatif bersifat iteratif dan kompleks serta membutuhkan waktu yang lama apabila dilakukan melalui perhitungan manual. Dalam kasus Teknik Kimia, pemahaman konsep dalam software mencakup hal-hal teoritis seperti penentuan model matematika dan penentuan parameter-parameter sistem. Hal itulah yang harus Vero kuasai dengan baik.

Untuk lebih jelasnya, marilah kita tinjau kedua kasus ini.
A: Vero pandai sekali mengoperasikan HYSYS, cekatan meletak-letakkan kolom fraksionasi, cepat dalam membuat aliran-aliran umpan dan produk. Katakanlah mouse komputer bergerak sedemikian cepatnya hingga semua orang terkagum-kagum. Namun, Vero tidak memiliki pemahaman yang cukup mengenai konsep distilasi dan akhirnya simulasi dijalankan hanya berdasarkan ‘coba-coba’ yang terlalu tidak berdasar.

B: Vero mengerti benar konsep distilasi multikomponen, kesetimbangan, dan konsep neraca massa. Namun, karena Vero sama sekali tidak bisa mengoperasikan HYSYS, Vero hanya bisa duduk di samping teman yang kebetulan cekatan. Dengan pemahaman konsep yang Vero miliki, Vero berhasil membantu dia dalam menentukan seluruh variabel dalam sistem seperti tekanan, temperatur, tebakan reflux ratio, tebakan low key dan heavy key value, dan akhirnya menjalankan simulasi dengan optimal dan tepat tujuan.

Nah dari kedua kasus di atas, Vero dapat lihat bahwa pemahaman konsep jauh lebih diperlukan dibandingkan dengan pemahaman teknik pengoperasian software. Teknik pengoperasian software dapat Vero kuasai apabila Vero telah terbiasa, tapi pemahaman konsep adalah suatu hal yang mutlak diperlukan agar segalanya bisa dilakukan dengan benar. Mulai sekarang, ada baiknya Vero membiasakan diri dengan software-software Teknik Kimia dan yakinlah bahwa cepat atau lambat itu semua dapat Vero kuasai. Lagi pula, gak mungkin kan ada orang yang terlahir untuk benar-benar tidak bisa ‘bersentuhan’ dengan komputer. Hehehe..

Semangat! Tiap masalah pasti ada solusinya!
Salam Majari Kanayakan.

The same is true of statistical distributions and parameters used to describe sample data. They offer important information, but the numbers can be meaningless without an illustration to help you interpret them. For instance, what does it mean if your data follow a gamma distribution with a scale of 8 and a shape of 7? If the distribution shifted to a shape of 10, would that be a good thing or a bad thing? And how would you explain all of this to an audience more interested in outcomes than in learning statistics?

Minitab’s probability distribution plots create the pictures that bring the numbers to life. Even novice users can reap the benefits that come from understanding their data’s distribution. Here are a few examples.

A building materials manufacturer: See what you’ve been missing

A building materials manufacturer develops a new process to increase the strength of its I-beams. The output shows that the old process fit a gamma distribution with a scale of 8 and a shape of 7 whereas the new process has a shape of 10. The manufacturer does not know what this change in the shape parameter means.

Minitab’s probability distribution plots show that the subtle shape change increases the number of acceptable beams from 91.4% to 99.5%, an improvement of 8.1%. Additionally, the right tail appears to be much thicker indicating many more unusually strong units. Perhaps these could spawn a premium line of products.

A specialist at a grocery store: Communicate your results

A quality improvement specialist at a grocery store chain wants to implement a new but expensive program to reduce discrepancies between the item’s shelf price and the amount charged at the register. No difference is ideal but any difference within the range of ± 0.5% is considered acceptable. In the pilot study, the mean improvement is tiny and the president doesn’t see the benefits of the smaller standard deviation. Therefore, the president is reluctant to approve the costly program. The specialist knows that the tighter distribution is key to the program’s success. To illustrate this, she creates this plot to show that the differences are clustered much closer to zero and most are in the acceptable range. Now the president can see the improvement.

Fabrication department of a farm equipment manufacturer: Compare distributions

The fabrication department of a farm equipment manufacturer counts the number of tractor chassis completed per hour. A Poisson distribution with a mean of 3.2 best describes the sample data. However, the test lab would like to use an analysis that requires a normal distribution and wants to know if it is appropriate. If the normal distribution does not approximate the Poisson distribution, then the test results will be invalid. The distribution plot can easily compare the known distribution with a normal distribution. In this case, it’s clear that the normal distribution, as well as the analyses that require it, won’t be a good fit.

How to create probability distribution plots in Minitab

It’s easy to create a probability distribution plot to visualize and compare distributions, and even scrutinize an area of interest. For instance, an analyst is interested in interviewing customers with customer satisfaction scores between 115 and 135. Minitab’s Individual Distribution Identification feature shows that these scores are normally distributed with a mean of 100 and a standard deviation of 15. However, the analyst can’t visualize where his subjects fall within the range of scores, or their proportion of the entire distribution.

1. Choose Graph > Probability Distribution Plot > View Probability. Click OK.
2. From Distribution, choose Normal.
3. In Mean, type 100.
4. In Standard deviation, type 15.
5. Click the Shaded Area tab.
6. In Define Shaded Area By, choose X Value.
7. Click Middle.
8. In X value 1, type 115.
9. In X value 2, type 135.
10. Click OK.

The scores in the region of interest (115-135) represent 14.9% of the population. This somewhat small percentage suggests that the analyst may have to place extra effort in finding a sufficient number of qualified subjects.

Putting probability distribution plots to use

Probability distribution plots provide valuable insight by revealing the deeper meaning of your distributions. Use these graphs to highlight the effect of changing distributions and parameter values, show you where target values fall in a distribution, and view the proportions associated with shaded areas. These simple plots also clearly and easily communicate these advanced concepts to a non-statistical audience.

Don’t get bogged down in hard-to-understand concepts and numbers. Instead, simply use Minitab to visualize what your data are trying to tell you.

This is part of a series of articles entitled Accessing the Power of Minitab. Visit to learn more.

Azeotropic distillation: Etanol dan air membentuk azeotrop pada komposisi 95.6%-massa etanol pada keadaan standar. Dan masih banyak lagi campuran senyawa yang berkelakuan demikian. Nah, bagaimana cara untuk memisahkan komponen-komponennya agar memiliki kemurnian melebihi komposisi azeotropnya?

Umpan campuran biner (2-propanol dan ethyl acetate) hendak dimurnikan dengan cara distilasi dan kedua aliran produk pemisahan diharapkan memiliki kemurnian 99,8%-mol. Umpan tersedia pada kondisi tekanan atmosferik dan temperatur ambien. Terdengar familiar di telinga anda? Setidaknya Anda tidak boleh lupa bahwa 2-propanol dan etyhl acetate ialah campuran azeotrop. Bila Anda lupa atau bahkan belum mengerti tentang campuran azeotrop, mungkin penjelasan singkat ini bisa sedikit membantu.

Apa itu azeotrop? Azeotrop merupakan campuran 2 atau lebih komponen pada komposisi tertentu dimana komposisi tersebut tidak bisa berubah hanya melalui distilasi biasa. Ketika campuran azeotrop dididihkan, fasa uap yang dihasilkan memiliki komposisi yang sama dengan fasa cairnya. Campuran azeotrop ini sering disebut juga constant boiling mixture karena komposisinya yang senantiasa tetap jika campuran tersebut dididihkan. Untuk lebih jelasnya, perhatikan ilustrasi berikut :

Titik A pada pada kurva merupakan boiling point campuran pada kondisi sebelum mencapai azeotrop. Campuran kemudian dididihkan dan uapnya dipisahkan dari sistem kesetimbangan uap cair (titik B). Uap ini kemudian didinginkan dan terkondensasi (titik C). Kondensat kemudian dididihkan, didinginkan, dan seterusnya hingga mencapai titik azeotrop. Pada titik azeotrop, proses tidak dapat diteruskan karena komposisi campuran akan selalu tetap. Pada gambar di atas, titik azeotrop digambarkan sebagai pertemuan antara kurva saturated vapor dan saturated liquid. (ditandai dengan garis vertikal putus-putus)

Bagaimana? Cukup jelas bukan? Secara logis, hasil distilasi biasa tidak akan pernah bisa melebihi komposisi azeotropnya. Lalu, adakah trik engineering tertentu yang dapat dilakukan untuk mengakali keadaan alamiah tersebut? Nah, kita akan membahas contoh kasus pemisahan campuran azeotrop propanol-ethyl acetate.

PFD Diagram: Simulasi distilasi biner campuran azeotrop propanol-ethyl acetate dengan menggunakan HYSYS.

Dalam pemisahan campuran propanol-athyl acetate, digunakan metode pressure swing distillation. Prinsip yang digunakan pada metode ini yaitu pada tekanan yang berbeda, komposisi azeotrop suatu campuran akan berbeda pula. Berdasarkan prinsip tersebut, distilasi dilakukan bertahap menggunakan 2 kolom distilasi yang beroperasi pada tekanan yang berbeda. Kolom distilasi pertama memiliki tekanan operasi yang lebih tinggi dari kolom distilasi kedua. Produk bawah kolom pertama menghasilkan ethyl acetate murni sedangkan produk atasnya ialah campuran propanol-ethyl acetate yang komposisinya mendekati komposisi azeotropnya. Produk atas kolom pertama tersebut kemudian didistilasi kembali pada kolom yang bertekanan lebih rendah (kolom kedua). Produk bawah kolom kedua menghasilkan propanol murni sedangkan produk atasnya merupakan campuran propanol-ethyl acetate yang komposisinya mendekati komposisi azeotropnya. Berikut ini gambar kurva kesetimbangan uap cair campuran propanol-ethyl acetate pada tekanan tinggi dan rendah.

Dari gambar pertama dapat dilihat bahwa feed masuk kolom pada temperatur 108,2 C dengan komposisi propanol 0,33. Pada kolom pertama (P=2,8 atm), komposisi azeotrop yaitu sebesar 0,5 sehingga distilat yang diperoleh berkisar pada nilai tersebut sedangkan bottom yang diperoleh berupa ethyl acetate murni.

Untuk memperoleh propanol murni, distilat kemudian didistilasi lagi pada kolom kedua (P=1,25 atm). Distilat ini memasuki kolom kedua pada temperatur 82,6 C. Komposisi azeotrop pada kolom kedua yaitu 0,38 sehingga kandungan propanol pada distilat berkisar pada nilai tersebut. Bottom yang diperoleh pada kolom kedua ini berupa propanol murni. Bila Anda perhatikan, titik azeotrop campuran bergeser dari 0,5%-mol propanol menjadi 0,38%-mol propanol. (*nahh apa lagi coba yang berubah?? hehe.. temperatur operasi jelas berubah.. karena tekanan berubah, maka temperatur dan komposisi juga berubah.. ingat termodinamika?? hehehe..)

Jadi, dengan metode pressure swing distillation ini, dapat diperoleh propanol dan ethyl acetate dengan kemurnian yang tinggi. Dan untuk lebih mengoptimasi proses, distilat keluaran kolom 2 dapat direcycle dan dicampur dengan aliran umpan untuk didistilasi kembali. Nah, bagaimana? Apakah metode seperti demikian pernah terbesit di benak teman-teman? Nahh.. marilah kita lebih memperhatikan dosen-dosen yang sudah bersusah payah mengajari kita.. Hehehe..