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This paper deals with an experimental investigation on the performance of a novel pulverized coal burner, featuring the introduction of an outer secondary air without swirling, as applied to an industrial boiler. Both cold air and combustion tests were conducted to investigate the effects of the secondary air on flow, combustion, and NOx emission from this novel burner. The measured flow fields, temperature distributions, and gas concentrations were presented. It was shown that, due to the presence of the outer secondary air, slagging in the adiabatic combustion chamber could be avoided and a NOx emission level of 600 mg/Nm3 was realized. In addition, the operating efficiency of the boiler was found to be greater than 89.50%, which was higher than that of the conventional industrial boilers.

Experiment research on the air flow rate measurement using tracer gas method in a 300mm internal diameter and 90° elbow duct are presented, which CO and air are selected as tracer gas and gas stream. Results show that the relative errors between the flow rate measured by tracer gas method and turbine flowmeter are varied in the range of -2.15%~1.69% when the injection point is upstream of the elbow on 7D~13D (D is the internal diameter of the duct), and the sampling point is downstream of the elbow on 10D~14D. The further distances of the injection point and sampling point are apart, the less relative errors of the gas flow rate measured by tracer gas method and turbine flowmeter are made. The injection flow rate of tracer gas should be matched with the gas flow rate in the duct. It is a simple and effective method that gas flowmeter online calibration with tracer gas method on the large diameter industrial gas pipeline transportation.

To investigate the mixing uniformity between tracer gas and gas stream in the duct, numerical simulations of the CO tracer gas and air mixing in a 300mm diameter and 90 degree elbow duct were performed on the commercial CFD software FLUENT, and the comparisons between the simulation results and experimental data were analyzed. Tracer gas is injected by 5-point discharge, the mixing uniformity between tracer gas and air is better than that of 1-point discharge. The results indicated that the tracer gas concentrations of simulations were agreed with the experimental data. Simulation results could provide a valuable guidance for gas flow rate measurement and online calibration for gas flowmeter with tracer gas technique.