Plastics Technology México: Ahorro de energía https://www.pt-mexico.com/rss/zones/ahorro-de-energia [ Secadores infrarrojos | Secado de PET | Mantenimiento del secador | Ahorro de energía | Preguntas generales sobre Secado ]   Ahorro de energía Pregunta:  ¿Puedo entender la unidad de frecuencia variable en el soplador, pero ¿cómo varía el funcionamiento del calentador con él? Respuesta:  El calor consumido es una función de la temperatura del aire y la cantidad de aire calentado. Esto se muestra en la ecuación: Q (kW) = 0.0003228 * scfm * ΔT. Puede reducir el calor consumido al reducir el aire calentado y al reducir la diferencia de temperatura de aire caliente. Normalmente, la temperatura a la que el aire se calienta es fijada por el material, sin embargo, un sobre enfriamiento usando demasiado aire o demasiado aire frío sistema de refrigeración del secado puede conducir a un aumento de la temperatura diferencial y a un mayor consumo de energía. El mejor sistema de control controla el flujo de aire y el sistema de enfriamiento para mantener el flujo de aire adecuado y evitar el sobre enfriamiento. Mark Haynie, gerente de producto de sistemas de secado, Novatec, Inc. Pregunta:  ¿Debemos controlar el flujo de aire con unidades de frecuencia variable o reguladores? Respuesta:  Ambos pueden alcanzar el objetivo, pero los reguladores no son una forma de control activo. A través de los cambios en la temperatura del material, la humedad del material y cualquier cambio en las proporciones masa fundida cambia la cantidad de aire necesaria y el cambio de flujo de aire. Las unidades de frecuencia variable pueden ser utilizadas para hacer estos cambios automáticamente y no requieren la intervención de un operario. Se puede hacer la configuración para hacer el ajuste apropiado y que se produzca siempre que sea necesario y no dejar los cambios a la discreción de cada operario. Mark Haynie, gerente de producto de sistemas de secado, Novatec, Inc. Pregunta:  ¿Cuántos sistemas de VFD están en operación en el mercado? Respuesta:  Hay docenas de ellos en operación de distintos vendedores. Algunos de estos tienen regulación automática de parámetros del proceso y algunos requieren que el operario haga los ajustes. El uso de VFD ha crecido muy rápidamente en los últimos años, gracias a que la reducción en el consumo de energía ha aumentado y ha disminuido el costo y el tamaño de VFD. Don Rainville, Consultor en temas de energía, Novatec, Inc. Pregunta:  ¿Están disponibles las unidades de frecuencia variable para todas las aplicaciones de rueda desecante, incluso si el material a secar no es PET? Respuesta:  Están disponibles en la mayoría de los modelos y para PET y otras resinas. El énfasis en la PET es una función de la energía utilizada. Los ahorros son más altos cuando las temperaturas de secado son más altas. Sin embargo, los secadores centrales de gran tamaño también pueden beneficiarse de esta técnica. Mark Haynie, Gerente de producto de sistemas de secado, Novatec, Inc. Pregunta:  ¿Qué controla la velocidad de la demanda de la unidad de frecuencia variable en el soplador de regeneración? Respuesta:  Esto varía entre los proveedores pero control mediante la temperatura del aire de retorno desde la tolva proporciona los medios más sensibles e inmediatos de supervisión y cambios de procesamiento. Cuando cambia la temperatura de la resina o la humedad, se refleja casi de inmediato en la temperatura del aire de retorno. Mark Haynie, gerente de producto de sistemas de secado, Novatec, Inc.   jue., 24 may. 2012 10:55:09 -0400 Automotive drives plastics processing Fifteen million units is my personal benchmark for annual U.S. auto sales. Fifteen million units is my personal benchmark for annual U.S. auto sales. The year 2012 could come close to, or even exceed, that number. The prospering U.S. automotive industry is driving the plastics processing industry hard on multiple fronts: quantity, quality, and innovation.

Any way you look at it, the U.S. auto industry is in a growth period. Automotive sales figures are a moving target, so to speak. Sales are commonly expressed in terms of seasonally adjusted annual rate (SAAR). Projected automotive sales in the U.S. for the calendar year 2012 range from 14-15+ million vehicles (combining cars and light trucks), the highest in 3-5 years, depending on the specific base of comparison. GM says
14-14.5 million, Autodata Corp. says 15.1 million, and other sources are within that range.

The overall figures are expressed in terms of sales, finessing the matter of where the vehicle was manufactured, and the origin of the components. “Made-in-the-U.S.” vehicles are chock full of components manufactured elsewhere. Also, U.S.-based companies set up manufacturing lines in other countries. Cars built in the U.S. are sold in the U.S., of course, but so are cars built in Germany, Japan, Korea, and elsewhere. Detailed statistics are also kept in terms of specific manufacturer, monthly sales, and so on (New York Times, 5/2/12, p.B3), but our focus here is really on plastics, not detailed automotive statistics.

Quantity needs for plastics component suppliers to the automotive industry are associated not only with the total number of cars built, but also with the model-year structure of the industry, which dictates delivery times. Once a design is settled on and production dates set, auto-assembly plants will not wait for a given plastics component. If one processor can’t or won’t deliver it, another will.

Let’s look at some quantities to get an idea of the orders of magnitude we are dealing with here. Taking 330 pounds per car as the average plastics content per vehicle (an ICIS estimate), for every hundred thousand (100,000) vehicles added to annual sales, that means an increase of (330) x (100,000) = 33 million more pounds of plastics to be conveyed. And that’s just the amount of change, not the overall quantity.

Quality demands are formidable, exceeded perhaps only by the medical sector. Quality is critical from making the car to buying and using it. Assembly lines are very intolerant of a need to slow or stop in order to deal with a defective component. At the other end of the business, consumers are not very forgiving of cars that require a lot of service, and Web sites make service records of given makes and years of cars more readily available than ever, to the chagrin of a manufacturer whose flaws get well publicized.

Innovation needs are related to function, appearance, and cost. Auto manufacturers are trying to reduce overall vehicle weight, which means increasing the use of plastics, including glass-fiber-reinforced and aramid-fiber components, thermoplastic elastomers, and the commodity plastics, engineering plastics, and blends.

Exhibitors at the NPE 2012 event held in April in in Orlando touted a wide variety of innovations for the automotive sector. One relatively easy breakout of automotive categories is this: interior, exterior and under-the-hood components. An SPI/NPE table that names more specific automotive targets for innovation, without naming exhibitor names, is at www.npe.org/Markets/content.cfm?ItemNumber=4443&navItemNumber=4289

Novatec, the sponsor of this Knowledge Center, supplies conveying and drying equipment for plastics processors, including those in the automotive sector, and continuously improves its technology in both drying and conveying. Particularly notable is the recent introduction of the Moisture Master™ equipment for continuously measuring and controlling moisture levels online. Drying systems are needed for some automotive materials, especially the nylons (polyamides), the blends of polycarbonate and acrylonitrile butadiene styrene (PC/ABS) and other hygroscopic materials. Novatec has recently entered the downstream extrusion equipment market as well.

For most of the 30+ years that I have been observing the plastics processing business, automotive has been the segment of the business in which the “grass is greener on the other side of the fence.” Processors who were not in the automotive sector wanted to be, for the volumes and the money. Processors who were serving the automotive market had reservations, as quality demands are unforgiving and payment arrangements are frequently difficult. It’s not a business for the faint of heart. However, the opportunity remains, especially in today’s growing automotive market.

You are already reading this on one of the links below, and for more information,
I encourage you to visit the other as well.
www.ptonline.com/kc/plastics-drying
www.ptonline.com/kc/plastics-conveying

Merle Snyder, Editor — Plastics Conveying & Plastics Drying Knowledge Centers

P.S. This commentary is mine, but the Knowledge Centers are sponsored by Novatec, whose personnel check this section for technical accuracy. This article is not a statement of Novatec policy. Please direct comments on this column to me at tekrite@gmail.com.

For additional technical information about inline moisture measurement,
contact Mark Haynie 410-789-4811, markh@novatec.com.
For additional technical information about conveying equipment,
contact Jim Zinski 410-457-1379, jimz@novatec.com.
 

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