Application of Data Validation and Reconciliation to Improve Measurement Results in the Determination Process of Emission Characteristics in Co-Combustion of Sewage Sludge with Coal

Michał Kozioł,Joachim Kozioł

doi:10.3390/su13095300

Michał Kozioł, Joachim Kozioł

Open Access

https://doi.org/10.3390/su13095300

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Abstract

One of the actions popularized worldwide to reduce the consumption of fossil fuels is the combustion of renewable fuels and the co-combustion of both of these fuels. To properly implement combustion and co-combustion processes in power-generation installations, operational characteristics, including emission characteristics are required. To determine these characteristics, tests must be conducted, within the scope of which, for individual operating stages of the installation’s work, the readings collected from a relatively large number of control and measurement instruments should be taken into account. All these instruments have different levels of accuracy, which, among other factors, bring about lower adequacy of the characteristics determined on the basis of these measurements. The objective of this study is to present possible adaptations of data validation and reconciliation methods to increase the adequacy of emission characteristics for the process of co-combustion of fuels. The methodology is discussed based on the example of studies on the co-combustion process of sewage sludge with coal in a grate furnace. The aforementioned characteristics were determined based on measurement tests of gaseous emissions of flue gas components. The tests were carried out for various preset operational conditions of the process, such as the thickness of fuel layer on the grate, the share of sludge in the fuel, the humidity of the sludge, the theoretical ratio of excess air to combustion, and the distribution of air stream during the process. The research object is described and detailed research results concerning two exemplary measurement tests are given, as well as the most important results referring to the whole research. The performed calculations indicate the necessity to take into account often significant corrections, which can amount to about 10% of the measured value.

Highlights

Many types of wastes have combustible properties with low or medium calorific value
One of the management methods of such wastes is to subject them to a co-combustion process with substances of higher calorific value, including non-renewable or renewable fuels
To forecast the effects of such a co-combustion process, for example, the emission of CO2, CO, NOx, SO2, as well as the content of combustible parts in solid products, the temperature of the obtained flue gases, and the thermal efficiency of the process, we apply process characteristics [1,2,3,4,5]. They are used as analytical functional relationships between the parameters defining each of the mentioned effects and the quantities controlling the process, for example, the amount of fuels, their composition, excess air for combustion, and the method of their supply to the process [1]

Summary

Introduction

Many types of wastes have combustible properties with low or medium calorific value (heating value). To forecast the effects of such a co-combustion process, for example, the emission of CO2 , CO, NOx , SO2 , as well as the content of combustible parts in solid products (in slag and ash), the temperature of the obtained flue gases, and the thermal efficiency of the process, we apply process characteristics [1,2,3,4,5] They are used as analytical functional relationships between the parameters defining each of the mentioned effects and the quantities controlling the process, for example, the amount of fuels (share of waste), their composition, excess air for combustion, and the method of their supply to the process [1].

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