| Abstract: | Hydrogen chloride (HCl) is a very difficult gas to measure, and its measurement is usually done by a batch procedure. The utility of a gas filter correlation analyzer (GFCA) for analysis of HCl as a combustion product in the cone calorimeter has been evaluated. The GFCA analyzer is a continuous on-line method. Optimum components and operating conditions for the sample transfer line from the cone calorimeter to the GFCA were determined in experiments where constant boiling hydrochloric acid (HCl) was used. The sample transfer line should be designed to prevent water vapor condensation in the transfer line or in the measurement cell of the GFCA. HCl will condense into any condensed water resulting in analytical losses. To avoid this, the sample transfer line should be constructed out of PTFE and include a dryer. Also, any segment of the sample transfer line ahead of the dryer should be heat wrapped and maintained above the boiling point of water. The GFCA analyzer was also evaluated in the cone calorimeter with PVC combustion products. For combustion products, 20 to 30% losses of HCl occurred in the sample transfer line. These were a constant amount of 34 ppm of HCl in the constant boiling acid experiments and 53 ppm in the combustion experiments. A mathematical model relating the response of the GFCA to the concentration of HCl in the duct of the cone calorimeter was developed. Important factors are the delay time in the sample transfer line, the losses in the sample transfer line, and mixing in the detection cell, By integrating the GFCA concentration-time profile and correcting for the losses in the sample transfer line the total yield of HCl can be accurately measured. The GFCA analyzer is an on-line method, gives fast and accurate results, and is highly useful for the measurement of HCl as a combustion product. |
