Some Studies on Energy Savings in Sponge Iron Plants

2003 ◽  
Vol 125 (3) ◽  
pp. 228-237 ◽  
Author(s):  
D. K. Biswas ◽  
S. R. Asthana ◽  
V. G. Rau

This paper presents the potential for energy savings in various capacity sponge iron plants by estimating heat transfer rates using stabilized and optimized temperature data within the rotary kiln/reactor. Air jet seal instead of mechanical seal arrangements at specific locations in the rotary kiln and cooler are proposed and this is shown to reduce the power consumption and the size of the centralized grease lubricating system. The paper proposes atomized water spray on the post combustion chamber instead of larger droplets to reduce the size of the water handling system, thereby saving energy. The paper also suggests optimization of the performance of a pneumatic coal injector by optimizing coal and air quantities.

Author(s):  
Richard Smith ◽  
Alan Roddis ◽  
Heinz P. Bloch

Applicable industrial standards for centrifugal pumps endorse several different sealing options as “best practice.” However, the overall acceptance of best practice techniques seems slow and is linked to the fact that sealing devices account for only a small fraction of the energy consumed by pumps. Yet, regardless of perception, significant energy conservation has been achieved by thoughtful sealing practices, as this paper will show. It will highlight case studies that provide guidance on issues of increasing technical and societal concerns relating to fluid emissions. Special attention will be directed to barrier fluid circulation devices used in dual mechanical seal arrangements as described by API-682 (Ref.1), a Standard widely used in the oil refining and petrochemical industries. The applicability of these ciculation devices to the Power Industry will be explained. Comparisons of three of the most widely used conventional integral flow induction/pumping ring devices will be made and the results of extensive testing presented. The paper and presentation also quantifies the value of advanced sealing technologies for pumps and highlights configurational differences between the newer and the more traditional (older) devices. Without exception, international utilities and power producers know that both energy and maintenance expenditures are affected by availability and reliability considerations relating to power generators and their turbine drivers. But feed water pumps and cooling water issues play their part as well. Consequently, a measure of attention has been given to “other big ticket items”, such as cooling tower losses and the like. However, there is compelling evidence that additional, less prominent or less obvious opportunities exist and that these can no longer be overlooked. Pump sealing falls into that category, although sealing devices and seal cooling account for only a small fraction of the energy consumed by pumps. In can be readily shown that significant energy savings have been achieved by thoughtful sealing practices. The general narrative and the implications conveyed by our case studies give visibility to the issues and provide guidance to the user.


2004 ◽  
Vol 126 (4) ◽  
pp. 519-523 ◽  
Author(s):  
Siddharth Bhopte ◽  
Musa S. Alshuqairi ◽  
Dereje Agonafer ◽  
Gamal Refai-Ahmed

The current numerical investigation will examine the effect of an impinging mixed convection air jet on the heat transfer rate of a parallel flat plate heat sink. A three-dimensional numerical model was developed to evaluate the effects of the nozzle diameter d, nozzle-to-target vertical placement H/d, Rayleigh number, and the jet Reynolds number on the heat transfer rates from a discrete heat source. Simulations were performed for a Prandtl number of 0.7 and for Reynolds numbers ranging from 100 to 5000. The governing equations were solved in the dimensionless form using a commercial finite-volume package. Average Nusselt numbers were obtained, at H/d=3 and two jet diameters, for the bare heat source, for the heat source with a base heat sink, and for the heat source with the finned heat sink. The heat transfer rates from the bare heat source surface have been compared with the ones obtained with the heat sink in order to determine the overall performance of the heat sink in an impingement configuration.


2006 ◽  
Vol 84 (4) ◽  
pp. 589-599 ◽  
Author(s):  
Donald I. Solick ◽  
Robert M.R. Barclay

Entering torpor can yield significant energy savings for temperate-zone bats but can be costly for reproductive females by slowing fetal development and reducing milk production. We studied western long-eared bats (Myotis evotis (H. Allen, 1864)) in the Rocky Mountains of Alberta to test the hypothesis that different costs of torpor result in different patterns of thermoregulation and roosting behaviour for reproductive and nonreproductive females. We radio-tracked bats to monitor body temperatures and locate roosts. We took roost measurements and inserted temperature data loggers to measure roost microclimate. Bats entered torpor frequently, but nonreproductive females spent longer periods in torpor, had lower minimum body temperatures, and entered deep torpor more often than reproductive females did, supporting the hypothesis that entering torpor is more costly for reproductive individuals. Roosts were located mainly in rock fields on steep, open, south-facing slopes. Reproductive females roosted in crevices between rocks located above or on the surface of the ground. Roosts warmed rapidly and reached warm daytime temperatures. Females roosted alone during pregnancy but formed small colonies within roosts during lactation when ambient conditions were cooler. Clustering may reduce thermoregulatory costs for both adults and young. Nonreproductive females roosted mainly alone in crevices in the ground. These roosts had cooler, more stable microclimates, allowing females to enter deeper bouts of torpor and remain torpid longer.


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