Thesis OPTIMIZACIÓN DEL SISTEMA DE TRANSPORTE DE MINERAL GRUESO PARA MAXIMIZAR GENERACIÓN DE ENERGÍA Y RENDIMIENTO
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Date
2019
Authors
TEUBER VON BORRIES, EDUARDO RENÉ
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Abstract
Las correas transportadoras son un sistema de transporte ampliamente utilizado en la industria
minera, específicamente en las áreas de procesos y operaciones, ya que permiten
trasladar diversos tipos de materiales a lo largo de grandes distancias. Por otra parte, se
adaptan con facilidad a las distintas características topográficas presentes en Chile, sobre
todo en la Cordillera de Los Andes. También poseen una alta capacidad de transporte,
con una diferencia significativa respecto a muchas otras alternativas. En Chile, la implementación y utilización de este tipo de sistemas se puede encontrar en diversas industrias,
pero en especial en el rubro minero.
El sistema de transporte de mineral grueso(STMG) de Minera Los Pelambres - que se
encuentra emplazado entre la planta de chancado y molienda - está compuesto actualmente
por Correas Transportadoras que operan en descenso producto de la topografía de
la faena. Esta pendiente negativa genera las condiciones necesarias para producir energía
eléctrica a través del uso de motores eléctricos asincrónicos, gracias al peso que ejerce el
mineral grueso sobre la correa, por lo que se les denomina correas regeneradoras.
Básicamente, las correas transportadoras se componen por correas unidas por empalmes,
estaciones de polines, contrapesos, y un sistema motriz compuesto por un reductor y un
motor. Para lograr impulsar las correas, y poder superar así las resistencias mecánicas,se
usa un motor eléctrico. En el caso de las correas regenerativas, se necesita una cantidad
mínima de mineral grueso de aproximadamente 2.400 [t/h], para el caso de MLP, para
pasar del estado de motor al de generador superando la velocidad sincrónica de este. La
correa sobre este nivel de envío tiende a acelerar, por lo que el proceso busca frenar la
carga para llegar a un régimen constante y evitar el embalamiento de la correa, que es un
estado de descontrol de la correa. El frenado de esta carga produce energía limpia para el
sistema de MLP, constituyendo un ahorro importante para la minera.
La presente investigación consta de la actualización de la curva Generación vs Rendimiento
(toneladas por hora), ya modelada el año 2000 en Minera Los Pelambres. Esta
debió ser actualizada según los datos registrados por el sistema PI, debido a repotenciamientos
de correa, es decir, aumento de velocidad de 6[m/s] a 6,8[m/s] e instalación de
dos motores en el sistema de correa, lo que permite un mayor rendimiento y por lo tanto
generación. Dado los cambios, la curva debe desplazarse y cambiar su resistencia al movimiento.
Se desea estimar la curva mediante correcto uso de datos y criterios estadísticos
para facilitar las posteriores actualizaciones de la curva y adaptar el uso operacional del
sistema en vías de optimizar el índice de generación (KWH/TPH).
Sin embargo, surge la siguiente interrogante: ¿Es posible determinar los datos correspondientes
a los puntos de operación actualizados de la correa?
Para eso, se estudió y analizó la data desde el punto de vista estadístico y contrastó de
acuerdo a los principios mecánicos y eléctricos por los cuales se rige el sistema de correas.
El sistema tiene un conjunto de motores que alcanza los 25[MW] de generación nominal o máxima según diseño y luego del repotenciamiento se llegó a una potencia nominal de 26[MW]. Hasta el momento se ha alcanzado una generación aproximada de
22,99[MW] a 10520 toneladas por hora de rendimiento, promedios de generación de
14,5[MW] y promedios de rendimiento de 7350,77[TPH], datos correspondientes al año
2018, procedentes de la base de datos otorgada por “PI System”. Se optó por muchos
procedimientos, entre los cuales la empresa prefirió por atributos como filtros por varianza
y a través de medición en el sistema de correas considerando por nivel de exactitud al
de medición en el sistema de transporte de mineral grueso, ante los anteriores, se usó la
medición en terreno como mejor sistema para seleccionar una operación más adecuada,
que permita la maximizaci´on de beneficios en función del costo de energía distribuida
por los diferentes horarios CMg[mills/kwh]. Todo lo anterior, con el objetivo de alcanzar
las 190[kton/día] propuestas como meta para el transporte del STMG, dando como resultado
17.3[hrs] de procesamiento de mineral a plena marcha (11000[tph]), obteniendo
la empresa un beneficio máximo de 35410.13[USD]. Dicho beneficio no considera los
gastos producto del consumo por detención de correa y asume que esta no anduvo en
vacío.
Conveyor belts are a transportation system widely used in the mining industry, specifically in the areas of processes and operations, since they allow the transfer of various types of materials over long distances. On the other hand, they adapt easily to the different topographic features present in Chile, especially in the Andes Mountains. They also have a high transport capacity, with a significant difference compared to many other alternatives. In Chile, the implementation and use of this type of systems can be found in various industries, but especially in the mining sector. The thick mineral transport system (STMG) of Minera Los Pelambres - which is located between the crushing and grinding plant - is currently composed of Conveyor Belts that operate in descent due to the topography of the site. This negative slope generates the necessary conditions to produce electrical energy through the use of asynchronous electric motors, thanks to the weight exerted by the coarse ore on the belt, for which reason they are called regenerative belts. Basically, the conveyor belts are composed of belts joined by splices, polines stations, counterweights, and a drive system consisting of a reducer and a motor. In order to drive the belts, and thus overcome the mechanical resistances, an electric motor is used. In the case of the regenerative belts, a minimum amount of coarse ore of approximately 2,400 [t / h] is needed, in the case of MLP, to pass from the engine to the generator state, surpassing the synchronous speed of the latter. The belt on this level of delivery tends to accelerate, so the process seeks to slow the load to reach a constant rate and avoid belt runaway, which is a state of belt control. The braking of this load produces clean energy for the MLP system, constituting an important saving for the mining company. The present investigation consists of the update of the curve Generation vs Performance (tons per hour), already modeled in 2000 at Minera Los Pelambres. This had to be updated according to the data recorded by the PI system, due to belt repowering, that is, speed increase from 6 [m / s] to 6.8 [m / s] and installation of two motors in the system belt, which allows a higher performance and therefore generation. Given the changes, the curve must move and change its resistance to movement. It is desired to estimate the curve by correct use of data and statistical criteria to facilitate subsequent updates of the curve and adapt the operational use of the system in the process of optimizing the generation index (KWH / TPH). However, the following question arises: Is it possible to determine the data corresponding to the updated operating points of the belt? newline For that, the data was studied and analyzed from the statistical point of view and contrasted according to the mechanical and electrical principles by which the belt system is governed. The system has a set of motors that reaches 25 [MW] of nominal or maximum generation according to design and after the repowering a nominal power of 26 [MW] was reached. So far, an approximate generation of 22.99 [MW] has been achieved at 10520 tons per hour of yield, generation averages of 14.5 [MW] and yield averages of 7350.77 [TPH], data corresponding to the year 2018, coming from the database granted by “ PI System ”. It was opted for many procedures, among which the company preferred by attributes as filters by variance and through measurement in the belt system considering by level of accuracy the measurement in the heavy ore transport system, before the above, was used field measurement as the best system to select a more suitable operation, which allows the maximization of benefits based on the cost of energy distributed by the different schedules CMg [mills / kwh]. All of the above, with the objective of reaching the 190 [kton / day] proposed as a goal for the transport of the STMG, resulting in 17.3 [hrs] of ore processing at full speed (11000 [tph]), obtaining the company a maximum profit of 35410.13 [USD]. Said benefit does not consider the expenses resulting from consumption due to belt detention and assumes that it did not go idle.
Conveyor belts are a transportation system widely used in the mining industry, specifically in the areas of processes and operations, since they allow the transfer of various types of materials over long distances. On the other hand, they adapt easily to the different topographic features present in Chile, especially in the Andes Mountains. They also have a high transport capacity, with a significant difference compared to many other alternatives. In Chile, the implementation and use of this type of systems can be found in various industries, but especially in the mining sector. The thick mineral transport system (STMG) of Minera Los Pelambres - which is located between the crushing and grinding plant - is currently composed of Conveyor Belts that operate in descent due to the topography of the site. This negative slope generates the necessary conditions to produce electrical energy through the use of asynchronous electric motors, thanks to the weight exerted by the coarse ore on the belt, for which reason they are called regenerative belts. Basically, the conveyor belts are composed of belts joined by splices, polines stations, counterweights, and a drive system consisting of a reducer and a motor. In order to drive the belts, and thus overcome the mechanical resistances, an electric motor is used. In the case of the regenerative belts, a minimum amount of coarse ore of approximately 2,400 [t / h] is needed, in the case of MLP, to pass from the engine to the generator state, surpassing the synchronous speed of the latter. The belt on this level of delivery tends to accelerate, so the process seeks to slow the load to reach a constant rate and avoid belt runaway, which is a state of belt control. The braking of this load produces clean energy for the MLP system, constituting an important saving for the mining company. The present investigation consists of the update of the curve Generation vs Performance (tons per hour), already modeled in 2000 at Minera Los Pelambres. This had to be updated according to the data recorded by the PI system, due to belt repowering, that is, speed increase from 6 [m / s] to 6.8 [m / s] and installation of two motors in the system belt, which allows a higher performance and therefore generation. Given the changes, the curve must move and change its resistance to movement. It is desired to estimate the curve by correct use of data and statistical criteria to facilitate subsequent updates of the curve and adapt the operational use of the system in the process of optimizing the generation index (KWH / TPH). However, the following question arises: Is it possible to determine the data corresponding to the updated operating points of the belt? newline For that, the data was studied and analyzed from the statistical point of view and contrasted according to the mechanical and electrical principles by which the belt system is governed. The system has a set of motors that reaches 25 [MW] of nominal or maximum generation according to design and after the repowering a nominal power of 26 [MW] was reached. So far, an approximate generation of 22.99 [MW] has been achieved at 10520 tons per hour of yield, generation averages of 14.5 [MW] and yield averages of 7350.77 [TPH], data corresponding to the year 2018, coming from the database granted by “ PI System ”. It was opted for many procedures, among which the company preferred by attributes as filters by variance and through measurement in the belt system considering by level of accuracy the measurement in the heavy ore transport system, before the above, was used field measurement as the best system to select a more suitable operation, which allows the maximization of benefits based on the cost of energy distributed by the different schedules CMg [mills / kwh]. All of the above, with the objective of reaching the 190 [kton / day] proposed as a goal for the transport of the STMG, resulting in 17.3 [hrs] of ore processing at full speed (11000 [tph]), obtaining the company a maximum profit of 35410.13 [USD]. Said benefit does not consider the expenses resulting from consumption due to belt detention and assumes that it did not go idle.
Description
Keywords
MINERAL GRUESO , RENDIMIENTO , GENERACION DE ENERGIA