Theoretical and experimental results of the investigation illustrate how the rotary kiln operation affects the oxygen demand in the combustion of meat and bone wastes. The main objective of this study was to achieve optimal CO and NOx emissions for the cyclic operation of a rotary kiln, including in stoppage/operation mode. The tests were carried out in a plant in Poland for thermal animal waste management. A rotary kiln with a maximum capacity of 1000 kg/h was used to incinerate bones, carcasses, processed meat and by-products. The results showed that excessive short-term (1 min) CO and NOx emissions could be prevented by using appropriate time settings for the kiln rotation and adjusting the air flow to the afterburner chamber. Despite the strong negative correlation between CO and NOx emissions, we found an operation level that met the strict requirements of the new EU Directive 2010/75/EU of the European Parliament and the November 24, 2010 Council on industrial emissions.

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This paper presents test results of thermal treatment (combustion) of meat and bone meal (MBM) within the context of an animal waste utilization plant. The test facility was equipped with a rotating combustion chamber. The energy and ecological aspects of the operation of this facility were analyzed. This article assesses the impact of the tested system on the natural environment with regard to the emission of pollutants into the atmosphere. In accordance with the chemical composition of the incinerated waste, the following compounds were analyzed: CO, NOx (nitrogen oxides), SO2, HCl, HF, TOC (total organic carbon) and dust. The concentrations recorded in periods of 0.5 and 24 h were in compliance with the admissible levels defined by European Union directives. An analysis of the energy efficiency of the energy recovery system used, which produces saturated steam for the technological needs of the utilization plant, was also carried out. The conditions for the achieved ecological and energy parameters were analyzed and presented synthetically using the multicriteria assessment method, with a simultaneous Pareto principle determination of the process optimum. The results of the research and the analyses of ecological and performance parameters presented in the paper may prove helpful in the design and operation of systems for thermal treatment of waste equipped with a rotating combustion chamber and other types of furnaces.

Processing efficiency optimization is often conducted in production environments. For turning, however, the introduction of noncircular cross-section workpieces generates new complexity. This paper presents the kinematic analysis and efficiency optimization of turning a noncircular cross-section workpiece on the basis of ISO 10208:1991 male rope thread machining, characterized by a smooth contour. This thread can be machined, for example, with standard thread turning or using X-axis motions characteristic of noncircular objects, i.e., rope threading. In that case, selecting the proper method and machining parameter values for efficiency can be more challenging than in circular cross-section workpiece turning. The latter method avoids many tool passes but requires highly dynamic movements of the machine in the X-axis. In addition to these two methods, a hybrid method is presented that is characterized by reduced dynamics in the X-axis and more passes than the rope threading method. A description of the methods using mathematical parameters is developed to optimize the process efficiency. Numerical calculations to select a method and its associated cutting parameters are carried out for exemplary cutting edges, theoretical roughness values, tool life models, and other variables. The obtained results and the optimization algorithm of the process are presented.