Ammonia acoustic chemometrics

The acoustic chemometric approach can also be used to monitor industrial production processes involving particles and powders and to provide a complementary tool for process operators for more efficient process control, or to monitor particle movement in a fluidized bed [7] for example. Below we illustrate the application potential by focusing on two applications process monitoring of a granulation process and monitoring of ammonia concentration. 

For industrial fertilizer production reliable ammonia concentration data are essential. An experimental setup for acoustic chemometric prediction of ammonia concentration has been tested in a full-scale industrial plant. Figure 9.22 shows a bypass loop with the orifice plate. The acoustic sensor was again mounted onto the orifice plate [5]. To ensure constant differential pressure and temperature of the ammonia flow, two pressure transmitters and one temperature sensor were used. Reference samples were taken at the sample valve shown in Figure 9.22. 

Figure 9.22 Experimental setup for assessment of acoustic chemometrics potential to predict concentration of ammonia directly from acoustic emission generated by cavitation/turbulent flow.

The full-scale industrial experiment demonstrated the feasibility of a convenient, nonintrusive aconstic chemometric facility for reliable ammonia concentration prediction. The training experimental design spanned the industrial concentration range of interest (0-8%). Two-segment cross-validation (test set switch) showed good accnracy (slope 0.96) combined with a satisfactory RMSEP. It is fully possible to further develop this pilot study calibration basis nntil a fnll industrial model has been achieved. There wonld appear to be several types of analogous chemical analytes in other process technological contexts, which may be similarly approached by acoustic chemometrics. 

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