RESEARCH AND ASSESSMENT OF THE ENVIRONMENTAL SECURITY OF BAKERY ENTERPRISES

Abstract

The paper considers how to decrease the concentration of nitrogen oxides in gas emissions of bakery enterprises. Nitrogen oxides (NOx) formed in the course of burning natural gas are responsible for more than 90% of an enterprise’s hazard category. So, it has been determined how much NOx is contained in exhaust gases emitted at different loadings on the floor of the oven at an enterprise, this parameter being the main characteristic of the effectiveness of ovens and their impact on the environment. The paper presents the results of experiments that have allowed determining the regression equations describing how the NOx quantity per unit of output in an enterprise’s exhaust gases depends on the amount of the fuel consumed and on the loading on the floor of baking ovens. The procedure of the experiments has been described, and the numerical results have been presented and analysed. It has been established that when making a loaf of wheat-flour oven-bottom bread weighing 0.9 kg, with 70% loading on the floor of an oven (PPC1381), the nitrogen oxides concentration in combustion products is 212.00 μg/m3, and the specific NOx formation is 292.25 μg/kg. The nitrogen oxides concentration is 152.00 μg/m3, and the specific formation is 306.00 μg/kg when the oven floor loading is 40%. If a similar range of products is baked in ovens Minel100 with the maximum-loaded and half-loaded oven floor, the production is accompanied by specific nitrogen oxide emissions of 239.50 μg/kg and 247.80 μg/kg respectively. When enriched buns of 0.1 kg are baked in ovens BN50 with the maximum-loaded and half-loaded oven floor, the process is accompanied by specific nitrogen oxide emissions of 209.20 μg/kg and 265.96 μg/kg respectively. The nitrogen oxides content in gases withdrawn from bakery ovens has been instrumentally measured. This has allowed obtaining regression equations of dependence of the specific NOx weight in gas emissions on the amount of fuel consumed and on the oven floor loading. It has been found that in the ovens considered, the nitrogen oxide formation per output unit decreased when the oven floor loading increased, because less fuel is needed to make up for the loss of heat accompanying the emission of fumes. The contributions of the argument parameters have been determined according to the regression model to estimate the quantitative dependence. The amount of nitrogen oxides depends on the oven floor loading. A mathematical model has been developed describing how nitrogen oxide formation depends on the oven floor loading and fuel consumption. The model can be used to introduce an industry standard of quantification of nitrogen oxides formed when manufacturing a unit of output.

Keywords

• nitrogen oxides
• breadbaking industry
• exhaust gases
• environment