Evaluación del impacto de las características de la madera y la generación de TSS/ADt en el proceso de cocción SF2.
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Date
2025
Authors
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Publisher
Universidad de Concepción
Abstract
El presente estudio evalúa el impacto de las características de la madera sobre la generación de Tonelada Sólido Seco por tonelada de celulosa producida en el proceso de cocción de la línea Santa Fe 2 (SF2) de CMPC, orientada a la producción de celulosa de fibra corta. El problema se asocia a variaciones del indicador de TSS/ADt, cuyo aumento puede elevar la carga de sólidos hacia evaporadores y desencadenar problemas de balance en el ciclo de recuperación química.
Se integra una revisión bibliográfica para sustentar el efecto de variables de madera y proceso, un levantamiento del estado de la planta mediante visitas y reuniones con áreas operacionales y laboratorios, además de un análisis de datos operacionales que incluye etapas de depuración, cálculo de indicadores y aplicación de herramientas estadísticas (estadística descriptiva, correlaciones y pruebas de hipótesis para la comparación entre periodos). Finalmente, se estructura un modelo causal que describe cómo las propiedades de la madera influyen en variables operacionales, generando cambios en las variables de resultado del área
Los resultados muestran que el año 2023 constituye un periodo estable y comparable con 2025 en términos de ritmos de producción, sin diferencias estadísticamente significativas, lo que permite utilizarlo como línea base para interpretar cambios posteriores. En la evolución temporal del indicador, se observa una disminución sostenida de TSS/ADt hasta 2023 y un aumento leve pero consistente en 2024-2025, lo que se interpreta como el establecimiento de una nueva condición operacional asociada a decisiones y ajustes dentro de la operación, más que a un evento específico. El modelo causal propuesto sugiere que la relación entre las propiedades de la madera y la generación de TSS/ADt se manifiesta principalmente de forma indirecta, al condicionar variables operacionales del digestor, como factores de hidráulicos y el control de severidad, las cuales inciden en el desempeño del proceso.
Por último, se recomienda fortalecer el monitoreo y seguimiento de variables críticas de materia prima y operación, tales como la humedad y densidad básica de la madera, junto con parámetros operacionales como la temperatura de cocción y los factores de extracción y recirculación, por su influencia directa en las variables de respuesta del sistema. Adicionalmente, se sugiere aumentar la frecuencia de medición del indicador orgánico/inorgánico para integrarlo de forma sistemática al control y análisis operacional. Finalmente, se propone incorporar la recomendación del fabricante del digestor para obtener un valor más representativo y consistente con el desempeño real.
This study evaluates the impact of wood characteristics on TSS/ADt generation in the cooking process of CMPC’s Santa Fe 2 (SF2) line, which is focused on producing short-fiber pulp. The issue addressed is associated with variations in the TSS/ADt indicator, whose increase may raise the solids load to the evaporators and lead to balance problems in the chemical recovery cycle. The methodology integrates a literature review to support the effect of wood and process variables, an assessment of the plant’s operating status through site visits and meetings with operational areas and laboratories, and an operational data analysis that includes data cleaning, indicator calculation, and the application of statistical tools (descriptive statistics, correlations, and hypothesis testing for period-to-period comparisons). Finally, a causal model is developed to describe how wood properties influence operational variables, resulting in changes in the area’s output variables. The results show that 2023 is a stable period and comparable to 2025 in terms of production rates, with no statistically significant differences, allowing it to be used as a baseline for interpreting subsequent changes. In the temporal evolution of the indicator, a sustained decrease in TSS/ADt is observed up to 2023, followed by a slight but consistent increase in 2024–2025, which is interpreted as the establishment of a new operating condition associated with operational decisions and adjustments rather than a specific event. The proposed causal model suggests that the relationship between wood properties and TSS/ADt generation is mainly indirect, as wood properties condition digester operating variables such as hydraulic factors and severity control which in turn affect process performance. Lastly, recommendations are proposed to strengthen the monitoring and tracking of critical raw-material and operational variables, such as wood moisture content and basic density, together with operating parameters such as cooking temperature and extraction/recirculation factors, due to their direct influence on the outcome variables. In addition, it is suggested to increase the measurement frequency of the organic/inorganic indicator to integrate it systematically into operational control and analysis. Finally, it is proposed to incorporate the digester manufacturer’s recommendation to obtain a production value that is more representative and consistent with actual process performance.
This study evaluates the impact of wood characteristics on TSS/ADt generation in the cooking process of CMPC’s Santa Fe 2 (SF2) line, which is focused on producing short-fiber pulp. The issue addressed is associated with variations in the TSS/ADt indicator, whose increase may raise the solids load to the evaporators and lead to balance problems in the chemical recovery cycle. The methodology integrates a literature review to support the effect of wood and process variables, an assessment of the plant’s operating status through site visits and meetings with operational areas and laboratories, and an operational data analysis that includes data cleaning, indicator calculation, and the application of statistical tools (descriptive statistics, correlations, and hypothesis testing for period-to-period comparisons). Finally, a causal model is developed to describe how wood properties influence operational variables, resulting in changes in the area’s output variables. The results show that 2023 is a stable period and comparable to 2025 in terms of production rates, with no statistically significant differences, allowing it to be used as a baseline for interpreting subsequent changes. In the temporal evolution of the indicator, a sustained decrease in TSS/ADt is observed up to 2023, followed by a slight but consistent increase in 2024–2025, which is interpreted as the establishment of a new operating condition associated with operational decisions and adjustments rather than a specific event. The proposed causal model suggests that the relationship between wood properties and TSS/ADt generation is mainly indirect, as wood properties condition digester operating variables such as hydraulic factors and severity control which in turn affect process performance. Lastly, recommendations are proposed to strengthen the monitoring and tracking of critical raw-material and operational variables, such as wood moisture content and basic density, together with operating parameters such as cooking temperature and extraction/recirculation factors, due to their direct influence on the outcome variables. In addition, it is suggested to increase the measurement frequency of the organic/inorganic indicator to integrate it systematically into operational control and analysis. Finally, it is proposed to incorporate the digester manufacturer’s recommendation to obtain a production value that is more representative and consistent with actual process performance.
Description
Tesis presentada para optar al título de Ingeniero/a Civil Químico/a.
Keywords
Madera, Celulosa, Hemicelulosa, Lignina