During the toubleshooting of ammonia synthesis loop pressure I found that there was some problem across the gas-gas exchanger bcoz its calculated temperature was not matching with the measured temperature. So we checked the Temp gauge at the first place & found it faulty. It was replaced & again temp mismatch was observed but this time difference was lower.
Therefore it was decided to measure the ammonia concentration in the hot gas at the exit for any leakage confirmation. Upon analysis it was found that the exchanger was leaking. It gave an opportunity prior to a major failure & major downtime to rectify the problem in a planned shutdown. On opening it was found that there was minor leakage from the seal packings.
The above probelm also contributed slightly to higher loop pressure due to higher ammonia concentration at the inlet of reactor compared to other plants.
After rectifying this we again found that actual ammonia at reactor inlet was still high. So another simulation was done. This time ammonia liquid separator was the culprit. The VLE data was indicating much lower ammonia concentration than actual one. So after few data points it was decided to check its demister pad for physical condition. On inspection it was found totally damaged & therefore ammonia carryover was taking place.
The rectification lead to a increase of 6% in the capacity at the same loop pressure.
Thus finally this program proved its value to the management and investment they made by sparing me for a month or so to prepare it. I thank again Mr. Pankaj Shah for giving me this opportunity.
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In recent years, everybody is dreaming about one cheaper & cleaner fuel ethanol. Though the cleanliness over its total life cycle is still a debatable point along with energy efficiency debates. I am considering few Nos which were presented in some othe blog for my visitors. In this we will see the total requirement & growth of Ethanol as fuel & as industry demand.
What is the total Oil demand of the world as whole. It is ~90 Million barrels/day, which gives us an annual demand of 32850 Million barrels/year. On the other hand world Ethanol production in 2005 was ~328 million barrels/day. Wonderfully it is only ~1% of the demand.
The rise in ethanol capcity in recent past has been ~15%/year which has caused a food grain price rise of 20-40% in last 3 years worldwide. So can you imagine the scenario if we go for even 20% replacement of oil - foregt about 100%. This is the scenario even if I delete all industrial demand of ethanol.
Add one more interesting factor that Ethanol's energy content is only 60% of the Gasoline / Oil content for the same mass as Ethanol is having 76 KBTU/Gallon while gasoline has 125KBTU/Gallon. So net equivalence is only 0.6% of current demand.
Energy production wise, I have already written my previous post Ethanol - Facts & Common Sense the lowest positive enrgy production says it produces 134 units of energy for every 100 Unit input. So we are basically generating (Even if I consider this report as 100% correct) than we are effective only 34/100 = 34%. While it is given as 74 units / 100 unit for gasoline. So it is having a net impact of 50% higher energy gain. Even if I consider this as a fact than also ethanol goes back to 0.9% equivalent to Oil demand.
Whereas actual fact is something different, as Oil production consumes ~1 Unit of energy for every 5 units of energy. Just a commonsense man ( No oil company will be able to make profit if it would have been consuming more than its content bcoz Oil is sold on the basis of its energy content not based on quantity). So Ethanol production itself is much more energy in-efficient.
Given this scenario, when food prices are rising steeply & grain shortage is there, I dont see even it is catching to 10% of the world oil demand in next 5 - 10 years period and if it does then be prepared for a world where no food will be available as currently the growth rate of agriculture sector in terms of produtivity is even less than 10% whereas we are talking about 100% rise every year at current levels.
How can you claim that Ethanol is a substitute for Oil......NO.....WAY. Forget it...
Moral - Never focus your strategy based on this wonderfully misleading fact which is fooling the globe.....
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This post onwards, my postings are not in actual order of occurence. The next job I did was the problem solving of higher loop pressure in ammonia plant synthesis loop. The loop pressure was running by 10% higher value i.e. ~220 Ata compared to 200 Ata in other similar size, identical, same technology plants of same vintage and company was unable to identify the reason for last 12 years as it was a problem since commissioning.
When I evaluated this system I used the ammonia sysnthesis converter simulation program developed in C++. The major first difference identified was that the overall conversion of reactants into ammonia was higher than other companies (We compared our data with identical plants). The reason of this difference was identified that the second bed in the converter was giving mor econversion & first bed was giving less compared to others.
Ammonia converter S-200 radial flow type Haldor Topsoe make has two beds with one interbed exchanger. Feed gas first goes to the shell annular space rises up providing cooling to the sheel & then enters to interbed exchanger & is preheated to the desired temp range. Then it goes to first bed radially exits from it at higher temp & goes to interbed exchanger shell side for cooling. Relatively cold gas enters to second bed & exits from the bottom.
Now on identification of above reason of higher overall conversion, less conversion in first bed, higher conversion in second bed was sufficient for identifying the problem area.
On simulation again with the actual conditions, we found that some amount of additional gas is required to enter to second bed directly wihtout passing thru first bed. At this point came the idea of some internal bypass or leakge in the exchanger first which was ruled out as it will result opposite to the actual phenomenon. It will lead to higher conversion in first bed.
So finally upon detailed analysis of reactor internals drawing for few days, the only possible way of gas flow to second bed was identified thry bottom support plate sealing.
Based on this it was decided to open the reactor in next turnaround but it was openend earlier due to basket failure which was also an unique phenomenon in this particular reactor. Such failures are not common but it was happening in my company for 4-5 th time.
Surprisingly it was found on inspection of plate that tightening bolts were loose & they were only hand fitted & probably engineer missed the step. This expalined both the reasons of high loop pressure & repeated failure of converter internal pipe. SO COSTLY..........MISTAKE..........A good learning for all of us.....................
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This blog was conceptualized to share the information for young process engineers who need guidance at each step in the early career of their professional life. Since May2007 I started active blogging. Now we had 100 Posts in 10 Months & 75 readers which is a very good growth specially when your focus area is so specific. I am not blogging for my own thoughts, day to day happening like my personal diary but this blog is meant for purely technical & useful learnings.
As promised earlier, I am now launching a page on my detailed work in Fertilizer industry where from I started my Career. On this page I'll be posting my jobs one by one as & when I get time.
I hope for your continued support in bringing more & more friends to encourage sharing of knowledge among a community of true professionals.
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