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This project is concerned with the application of fluorescent dye technology for leak detection in pulp and paper recovery boiler systems in order to avoid a smelt / water explosion. The dyes’ property to absorb light of short wavelength and emit light of a longer wavelength (fluoresce) is what makes them a quintessential candidate for the desired sensor technology. The projected benefits of this technology pertain to cost-effectiveness and safety of recovery boiler operations.

For all purposes, the inert dye pyrenetetrasulfonic acid (PTSA) was used as a tracer agent. Multiple methods of experimental design were attempted to determine the reaction kinetics of the aforementioned dye. These methods involved exposing the dye to a specific temperature and monitoring its decomposition rate manually using a fluorometer. The dye was exposed to elevated temperature and pressure conditions in microwave reactors, such as Biotage and CEM Microwave. A design of experiments protocol was developed and executed, and the data collected was analyzed.

It was established that PTSA decomposed on a 1st order reaction rate, and corresponding mathematical models were established using mass and energy balances. MATLAB simulations were developed and compared with actual experimental data conducted in a continuous stirred tanks reactor (CSTR) to simulate the real-time conditions of a leak environment. The data collected was also used to demonstrate the accuracy of the mathematical model. The leak detection system is based on steady-state conditions using the PTSA mass balance model as a reference point for any changes that might occur in the system.

The decomposition rate of PTSA was monitored through careful recordings of a fluorometer. The decay rate analysis shows a decrease in the dye concentration in water with respect to time. The MATLAB simulation curve demonstrates the logarithmic relationship per the CSTR method at 150 °C and 200 °C.

Further research and experimentation is required to understand the dynamics of these fluorescent dyes and their rate kinetics at elevated conditions to match the 10 MPa and 480 °C recovery boiler conditions. This innovative method of applying such world-class detection technology will ultimately mitigate risk by saving lives of employees in the industrial facility and facilitate the process of maximizing profit and minimizing costs associated with a shut-down in the case of a leak.

Publication Date



Chemical Engineering | Engineering

Faculty Advisor/Mentor

Rudy Krack

VCU Capstone Design Expo Posters


© The Author(s)

Date of Submission

May 2018

Sensor Technology using Fluorescent Dyes