OP-FTIR Based Emission Monitoring and Its Data Analysis Methods

Hao Li, CTTFS, CItyU

The Emission Problem

Pollution from transportation emission has become the second largest contributor of air toxics and greenhouse gases pollutions.

Emissions from transportation have increased by about 27 percent since 1990 , making it the fastest growing source of the emissions.

Ship Emission Regulations

The Government of HKSAR is seeking legislation to mandate all ocean-going vessels (OGVs) to use cleaner fuel (Sulfur content < 0.05%) while at berth in Hong Kong effecting from 2015.

Current emission control : based on checking certificates, Oil Record Book, and bunker delivery notes, which are not hard to falsify.

Urgent need for techniques to remotely monitor emissions by individual vessels and vehicles

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Measurement Techniques

Measurement of SO2 content of the exhaust plume can be performed in 2 different ways:

Sample based:Mobile laboratoryOnboard Emission MonitorUAV + Electrochemistry sensors/Canister

Optical based:FTIR (Fourier Transform Infrared Spectrometry)UV-DOASLIDAR

Passive FTIR Monitoring System

Detector Target

Real time Infrared Spectrum

Monitoring

Identification and concentration of gas emissions

Past Outdoor Experiments

Experiments conducted last year:

Locations Time Target

Steel Plant 2013.4. Smokestacks

Airport 2013.7. Airplanes

River Port 2013.11. Barges

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CO2 O3 H2O

Low resolution (16cm-

1)

High resolution (1cm-1)

Steel Plant Experiment

Airport Experiment

Civil Airplanes in LTO cycle (overhead, apron, runway)

Airport Experiment

Software and Data Processor Development

1. Pre-processing of Data Collected (Spectrum conversion

from electrical signal, Calibration)

2. Determination of possible feature bands, and selection of

scans to be measured.

3. Develop Gas Detection Model and Fit Procedure to measure

gas concentration and emission rate.

Data Analysis of gas spectra (CO for instance)

CO’s feature band: around 2020-2230cm-1(4.7um)

NIST Library MODTRAN Simulated Absorption Data

Feature Band Selection

Background and Target Spectra

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Gas concentration Calculation

Transmittance is calculated based on the Three layers model,

Concentration c, gas cloud depth l, and transmittance has the relationship based on Lambert-Beer law：

Finally the gas concentration is, calculated by a fit procedure

Example of fit outcome

Correlation Coefficient = 79.88%estimated concentration = 20.16ppm

Backward Lagrangian Stochastic(bLS) models to determine emission rate.

Future Experiment Plan

Field experiment in Hong Kong Port (Kwai Chung Container Terminals, 2015 start)

Ship In-Port SO2 emissions to monitor fuel switching procedure

Data Analysis Innovation - TSA

Spectral Domain

Time Domain (NEW)

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THANK YOU!