October 31, 2007

Process Engineers - Real Challenges Or Mistakes

Many forums or dicussion board / Blogs will tell you about the role of process engineers in the chemical manufacturing industry. But you may rarely find out the real technical challenges faced by a process engineer. Recently I faced some of them & then thought to write on this issue.

The most important out of several ones is the availability of CORRECT DATA.

The role of process engineer includes the following:
  1. Process Scheme Development using technical improvement measures.
  2. Process Improvement using technological developemnts.
  3. Process Troubleshooting.
  4. Productivity & Efficiency Improvements.
  5. Energy Conservation & Management activities.
  6. Technology Transfer etc.

Therefore, you need to search lot of data required for your analysis. Out of this Chemical properties data, if available, is correct ~98% of the time & for remaining 2%, if any variation is there, it may be due to various other reasons e.g. the product specifications are different, product is not so common, not listed in standard database etc.

However, the data e.g. solubility, Distribution coefficient etc is varying widely. For example recently I was working on a job of recovering Acetic Acid from Liquid effluent. My team member listed few solvents used for LLE of acetic acid. MTBE was one of them.

Based on our selection criteria on different parameters when we shortlisted 2-3 solvents as most probable & economical options, we found that MTBE topped the list due to high distribution coefficient of 3.8 (As listed in one of the papers, I wont mention the link) and very low boiling point of ~55°C.

So we planned for it & invested time & money when we carried out our experiment, it was found that the D was ~0.95 or so. Initially, we were surprised by those kind of results, then after repeat tests & analysis, we re-started searching literature & found that it is also listed as 0.6.

So which one is correct?????????

Why should we rely on them????

These 2 are the critical questions, & I am sure it is faced by many process engineers from time to time.

Plan for intital feasibility based on the data and do some lab work before you propose anything if you don't have any prior experience on the concerned issue/system.

In the second case, if you go for any improvement planning in your existing processes be it capacity, energy saving, equipment performance or anything - you again need base data. In most of the cases you practically have Temperatures & Pressure available on your DCS or field instrument. However you do not have critical flow rates which are more important sometimes than P&T data alone.

For example when you check the performance of pumps specially in case of cooling water pumps you generally dont have accurate flow measurement.

In such cases we need to do some fundamental work of heat & mass balance across critical equipment(s). Or some tricky experience based like I use shutoff head and actual head to find out flow measurement alongwith system curve plotted based on different Q & H combinations.

Why industry do not push for providing sufficient gadgets required for efficiency / performance measurements which helps a lot in future in identifying problems, improving performances, production etc.? The cost of such installations is only a fraction of what can be saved from these exercise results.

Why a process engineer is required to do so much; wasting time & energy??????????

The problem lies with the process / project engineers itself. They do not recognize the importance of such gadgets at the conceptualization stage of the project and do not add up the fractional cost to keep themselves under targetted budget.

Everyone of us should now onwards focus; on putting these instruments in the field starting from the prelim stage of the project. It will help & save lot of money for your company and for you as well.

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