non-pollutant ammonia burning?

[vmthcs]

I am interested in non-pollutant destruction of limited quantities of non-pure non-valuable ammonia as sub-product in stokbreeding vastewater treatment industrial plant in Spain, as none atmospheric or vater emission of NH3 is allowed in this country.

This plant will treat 13.000m3/h of that vaste and produces around 800kg/h of 12% ammonia solution wich also contains few quantities of methil-mercaptan, ethil-mercaptan and other highly odoured organic compounds.

Actually we (my company) are in early dessign phase, and we are considering two possibilities:

a) process this solution with chemicals to render well solid ammonia sulphate, well liquid fertilizer (by the way, this has a high operation cost for a low-priced product)

b) burning ammonia with some added fuel (argeline natural gas, 90% methane) leading N2, but also non negligible quantities of NOx. In that case we need to reduce that NOx but we don´t know any commercialy available catalizer (or whole process) capable to do that.

I will thank earnestly any information or reference you could provide me about the second path (b)

 

[qshtr]

vmthcs:

I'm working on a similar problem. Our client has 40 m3/h of water from coking plant that contains ammonia, H2S, cyanides and other compounds. We were thinking of stripping ammonia with steam at high pH values and then combustion of ammonia. In this process there are unwanted competitive reactions (producing NOx). Combustion of ammonia is a high temperature process (>1200 C)and it produces some amount NOx. This amount of NOx depends on process design. As far as I know combustion of ammonia is not an option in areas where strict environmental laws are applied.

Technological solution we have chosen involves stripping of NH3 with steam and catalytic ammonia cracking to N2 and H2, which is then returned to coke gas pipeline. These reaction also needs high temperature (approx. 1200 C) but there are no NOx or SO2 formed. Catalyist is Nickel based and has life time of about 6 years. I know this is not exactly as in your case, but I hope this can help you.

I think you should think about other possibilities and not combustion of ammonia. BTW: For removal of NOx that are produced in many high temperature processes are usually 2 possibilities:

1. SNCR - selective non-catalytic reduction
2. SCR - selective catalytic redusction

both processes use AMMONIA as reducing agent. So the loop closes...

Finally one last suggestion: contact company PRANTNER in Germany (

http://www.prantner.de).

They have experience in catalytic ammonia oxidation and might help you.

best regards

qshtr