Layout of the denitration ammonia water tank area
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This post was last edited by TNLIH on 2016-10-27 at 16:41. I have a question for everyone: in the denitration design of power plants, ammonia water (15-30%) is used as the reactant. Currently, there are two 80-cubic-meter horizontal tanks for storing ammonia water (one in use and one as a backup), two pumps for transferring ammonia water (one in use and one as a backup), four pumps for transporting ammonia water, and one pump for handling wastewater. Can these pumps be placed outside the fire dike as pumps dedicated to this tank system, without any restrictions regarding safety distances? After examining the designs of ammonia water storage areas created by several other design firms, as well as looking up some pictures and information online, it seems that many of these firms place the pumps outside the fire dike, without adhering strictly to the required 8-meter distance specified for Class C storage tanks. Could it be that the fact that these pumps are considered pumps dedicated to a specific system allows for shorter distances between them? I hope everyone can give some advice
Firstly: It is inappropriate to consider 10–35% ammonia solution as Category C. Although 3.2.15 of DL/T5480－2013 suggests that it is advisable to treat it as Category C, the explanatory notes state that this is only a principle-based provision and further research is needed in the future. In the actual list of hazardous goods, 10–35% ammonia solution is classified as a “non-flammable, non-toxic gas” (note: it’s indeed a gas, no mistake here!) ), so the best choice is Class D or Class E. Secondly, 10–35% ammonia water is non-flammable, and there is no need to build fire dikes; a simple retaining wall is sufficient. The ammonia water pump can be placed outside the cofferdam.
Thank you for your reply, friend. It seems that everyone is considering similar factors; essentially, ammonia is not dangerous, and it’s different from Category C as specified in petrochemical standards. Since safety requirements are quite strict at present, yet the conditions on site don’t allow it, this issue has remained a source of confusion.
This is a great question; I was exactly looking for it
Was it then placed directly outside the dike? Also, are your storage tanks designated as pressure vessels?
I have a question: since the equipment in the ammonia area is equipped with explosion-proof features, do the pumps and electric actuators that are located outside the ammonia area’s enclosure also need to be explosion-proof? Thank you!
Although low-concentration ammonia solution is not considered a flammable material, given its tendency to evaporate, the resulting ammonia gas is a flammable and explosive substance. Moreover, since ammonia gas is lighter than air, a zone free of explosions must be established within a certain range above areas where leaks of ammonia gas might occur; electrical equipment and lighting fixtures must be designed to be explosion-proof.
Is it sufficient to consider only the spacing required for maintenance and operation when determining the distance between ammonia tanks?:) For those 20% ammonia tanks that are not insulated and operate at atmospheric pressure, and are equipped with flame-arresting vent valves, is there a risk of explosion in such areas?