3 replies to this topic

[tarafdar]

For ammonia production there are several process licensors.Again each licensor may have more than one process for it.For a particular process the licensor claims a certain energy consumption figure/MT ammonia.
In real field due to geographical location this should very considerably.Humidity,temp,barometric pressure all will effect the energy consumption(we may compare a similar plant in Finland/Libya/Indonesia).
So what is the reliability of this figure?Is it just a reference value or a commercial propaganda?

Thanks

Edited by tarafdar, 10 September 2011 - 01:58 AM.

[ankur2061]

tarafdar,

I don't think that utility consumptions (including power) can vary dramatically from one place to the other. However, there may be local constraints on a certain type of utility. For example, in a desert environment, water for cooling purpose would be a very costly proposition and it might make sense to use air cooled heat exchangers. This however does not mean that the power cost has varied too much from a plant in a desert area to an area where water is plentiful. If you do a detailed utility consumption you will find that while in a desert environment the power consumption pattern has moved to air cooled exchanger electric motors in an area of plentiful water the power consumption has shifted to the pumping costs of the water.

Geographical factors and local regulations do play a role such as the cost of fuel in generating electricity, but for most licensors of any kind of chemical technology these figures do not vary to a great extent. Most technology licensors provide a safe margin on utility consumptions for plant guarantee runs.

One of the selection criteria for any kind of technology is also the utility guarantee figures and there are LD (Liquidated Damages) or penalty clauses in most contracts if the gurantee figures are exceeded.

In a nutshell, no technology licensor (including ammonia technology) will have enormous amounts of variation in their power consumption figures due to varied geographical locations. It just doesn't make sense.

Regards,
Ankur.

[kkala]

Agreeing with Ankur, following additional remarks might be useful.
1. Various ammonia process designs have a wide variation of the pressure required upstream the catalytic reactor. See http://en.wikipedia....onia_production, where "the ammonia synthesis loop operates at absolute pressures ranging from 60 to 180 bar depending upon which proprietary design is used" (I remember ~400 barg as upper limit some 40 years ago). We cannot say that power consumption varies 3 fold, seeing that it also depends on the recycling (http://www.cheresour...__fromsearch__1, attached NH3balance.xls), but (inlet flowrate * pressure) apparently varies widely, and so does power consumption. This must be the main reason for the variation, not the climatic conditions.
2. Nevertheless your requisition has to clearly state the climatic conditions valid for the performance guarantees to be quoted. These will be the climatic conditions expected during the guarantee test runs.
In case some of these conditions are different during actual test runs, "corrections" mutually agreed in advance should be made, to "reduce" the results to the contractual climatic conditions. Penalties have to be based on detected differences (if any).
3. I would avoid the term "liquidated damages", not pleasant to many dealers (may mean loss of your profit, see below), but clearly define the penalties in a rather justifiable way, even though not explained to bidder at that time.
E.g. for power consumption up to 0.5% higher, no penalty (due to uncertainty of measurements); for every 1% further increase of guaranteed consumption A Euros (based on incurring extra operating expenses for (say) 10 year operation); for power consumption higher than 105.5 %, "make it good", that is implement all necessary modifications (free of charge) for the guarantees to be fulfilled. The latter includes new equipment and extra labour by Supplier, and can have a serious Project delay, whose financial consequences are not charged to Supplier, at least according to "legal practices and customs" around here. It is pointed out that penalties cannot exceed a percentage (set by law) of total Contract price, say 10%.
By writing such terms in the contract with an experienced Supplier, you can be pretty sure you will get what guarantees say.
4. Above has considered ammonia synthesis only, not upstream hydrogen production and purification. However spirit would be same for hydrogen unit too.

Edited by kkala, 10 September 2011 - 05:09 AM.

[tarafdar]

Thanks for your reply.