Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 31.400,001.200,00N2O emission level in ppm1.000,00800,00600,00400,00200,000,00Jan-02Apr-02Jul-02Oct-02Dec-02Mar-03Jun-03Sep-03Dec-03Mar-04Jun-04Sep-04Dec-04Mar-05Jun-05Sep-05Dec-05Figure 3.11: N 2 O emission before and after commissioning of the combined tail gas treatment[100, AMI, 2006]Cross-media effectsAmmonia consumption.Operational dataData of the example plant:• type: M/H plant (3.3/8 bar)• capacity: 1000 tonnes/day• volume flow: 120000 Nm 3 /hour• NO x in tail gas: k 500 ppm• N 2 O in tail gas: 800 – 1400 ppm, typically 1000 – 1100 ppm• the gauzes are changed approximately twice a year, absorption stage operated at 25 ºC.ApplicabilityGenerally applicable to new nitric acid plants. Applicable to existing nitric acid plants with tailgas temperatures m 420 ºC without major reconstruction of the plant. According to [104,Schöffel, 2001], the following plant types show the required tail gas temperatures (or higher):• M/H plants of recent construction• H/H plants (there are only a few in Europe).Examples with high tail gas temperature are given in [88, infoMil, 1999, 103, Brink, 2000]:• the M/M plant of DSM in Geleen (450 ºC, commissioned in 1968)• the M/M plant of DSM in IJmuiden (400 ºC, commissioned in 1966)• the M/H plant of DSM in IJmuiden (500 ºC, commissioned in 1987)• the M/H plant of DSM in Geleen (500 ºC, commissioned in 1989).According to [119, Hu-Chems, 2006], tail gas temperatures can be increased within certainlimitations, by removing heat transfer surface from the process cooler and installing an internalbypass, in the example from 387 to 435º C.128 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers