Έπειτα από τη μελέτη των μεθόδων που παρουσιάστηκαν στα προηγούμενα κεφάλαια, εξήχθησαν ορισμένα συμπεράσματα, σχετικά με τα μειονεκτήματα και τα πλεονεκτήματα που εμφανίστηκαν στον τρόπο λειτουργίας, καθώς επίσης και στα πεδία εφαρμογής της κάθε μεθόδου.
Παρακάτω παρατίθενται αναλυτικότερα τα σημεία που χρήζουν περισσότερης προσοχής.
Σχετικά με την φασματομετρία FTIR, αποτελέσματα από μετρήσεις πεδίου (που υπάρχουν στη βιβλιογραφία), δείχνουν ότι η μέθοδος αυτή είναι αρκετά ικανή για τηλε – ανίχνευση μεθανίου. Παρόλα αυτά η ακρίβεια των αποτελεσμάτων εξαρτάται άμεσα από τις καιρικές συνθήκες και συγκεκριμένα από την ταχύτητα του αέρα και από την διαφορά θερμοκρασίας ανάμεσα σε αυτήν του ανιχνευόμενου μεθανίου και σε αυτήν του περιβάλλοντος. Για το λόγο αυτό, η ελαχιστοποίηση της αβεβαιότητας, απαιτεί πολλές δειγματοληψίες.
Η χρήση των laser διόδων με εξωτερική κοιλότητα και βασισμένα στην τεχνολογία FBG αποτελεί μια αξιόπιστη λύση για την φασματοσκοπία αερίων με γραμμές απορρόφησης στα 0.7 – 1.7 μm. Για εφαρμογές που απαιτούν ανίχνευση ενός ή περισσότερων γραμμών απορρόφησης, αυτά τα laser είναι μια εναλλακτική και φθηνότερη λύση έναντι των διαδεδομένων lasers τεχνολογίας DFB (κύριο μειονέκτημα των laser DFB είναι η πολυπλοκότητα της χρήσης τους, η οποία απαιτεί επέμβαση στη δομή τους, πράγμα που τα καθιστούν αρκετά ακριβά).
Η φωτοακουστική μέθοδος με ταυτόχρονη χρήση ενός laser διόδων στο near-IR, αποτελεί μια αρκετά ενδιαφέρουσα τεχνική, καθώς είναι σε θέση να προσφέρει μία ανίχνευση μικρότερη της τάξης των ppm. Τα κύρια πλεονεκτήματα της μεθόδου αυτής είναι το υψηλό επίπεδο ικανότητας ανίχνευσης και η σχετικώς απλή πειραματική δομή της.
Οι ανιχνευτές TDLAS (Tunable diode laser absorption spectroscopy) είναι αποτελεσματικοί στον εντοπισμό διαρροών και στις μετρήσεις των LEL (lower explosive limit). Δεν απαιτείται επαναβαθμονόμηση και είναι ικανοί να ανιχνεύουν αιθάνιο άρα και φυσικό αέριο. Αλλάζοντας το κέντρο μήκους κύματος της συσκευής, μπορούν να ανιχνευθούν και άλλα αέρια, ανάλογα με τον συντελεστή απορρόφησής τους, διατηρώντας το ίδιο υλικό και λογισμικό.
Η ανίχνευση εκπομπών μεθανίου από το διάστημα (π.χ. SCIAMACHY), προσφέρει μεν μια συνολική εικόνα της υφιστάμενης κατάστασης των συγκεντρώσεών του σε όλο τον πλανήτη, είναι δε μια χρονοβόρα διαδικασία, εξ’ αιτίας της εποχιακής διακύμανσης. Για ακριβέστερα αποτελέσματα απαιτούνται και επίγειες μετρήσεις.
Οι οπτικοί ανιχνευτές έχουν σχετικά χαμηλότερο κόστος αγοράς από τους ανιχνευτές καταλυτικών συσκευών, αλλά υστερούν λόγω της εξάρτησής τους από τη θερμοκρασία. Για μια υψηλή ικανότητα ανίχνευσης, το εύρος θερμοκρασίας πρέπει να κυμαίνεται μεταξύ –20 και 50οC, αντίθετα, στους ανιχνευτές καταλυτικών συσκευών η θερμοκρασία είναι ένας ουδέτερος παράγοντας.
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