Processes 2021 , 9 , 1707
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The current work investigates options for reducing emissions without machinery replacement or fuel substitution by focusing only on the maintenance of machinery and minor reforms of maintenance guidelines. The study does not seek to determine OEEs, characterized by relating the availability of equipment, their performance, and the quality rate [44], but analyzes some of these elements together with CO 2 emissions and the identification of patterns that facilitate their increase while reducing emissions. The main aim of this study is to analyze the management of environmental indicators, such as ‘t CO 2 /t Paper’, and its decomposition into several subcomponents to identify their effects and the variables involved in the drying process on CO 2 emissions. This work does not consider indirect emissions, such as those from other companies, including purchased electrical power, raw materials, the transport of finished products, or wastewater treatment. 2. Methodology The methodology is based on the case study, which is focused on papermaking. The facility under analysis uses 77% of its total energy on drying paper using steam. This section includes a description of the papermaking process, the methodology used to determine the CO 2 emissions, the data collection strategy, and the maintenance levels. This work considers the CO 2 -eq emissions produced by the plant from the combustion of natural gas used to generate steam for drying paper (in the studied factory, this is the only source of thermal energy used in the dryer section). These emissions are included in the ETS scheme. 2.1. Levels of Maintenance To manage these indicators, TPM and techniques such as total employee involvement (TEI) and continuous performance improvement (CPI) are analyzed and implemented [51]. TEI is implemented to motivate maintenance and production personnel, creating mixed work teams to analyze conditions where participation is facilitated and encouraged to generate action guidelines. Three levels of action are proposed depending on the frequency of analysis, follow-up, and/or action required. CPI actions are small changes; in particular, employee observations are considered, and initially, major reforms or new installations are not, making improvements that are measurable and repeatable and that are as inexpensive as possible. Employees are made accountable for improvements. This methodology begins to be implemented at the end of 4 years, and regarding maintenance, three levels are defined to verify the influence of several indicators, called subindicators, on the indicator ‘t CO 2 /t Paper’: The first level of action involves maintenance and manufacturing workers, who collect and monitor the process data that relate directly or significantly to the parameters they can control. These records are collected frequently enough that maintenance or production workers can involve themselves in follow-up. The second level reviews the monthly data collected by the first action level; this involves technical personnel and environmental management staff, who check whether the values obtained are compatible with the historical consumption and recent measures taken to reduce the indicator. The third level of action features bimonthly meetings involving a small group of people from the second and third levels. This level analyzes the variation in the identified subindicators that affect the main indicator ‘t CO 2 /t Paper’. This third level takes the necessary actions to adjust the desired value of each subindicator to reduce the main indicator, ‘t CO 2 /t Paper’.
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