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OPTIMIZATION OF SECONDARY COOLING WATER FILTRATION IN A CONTINUOUS STAINLESS STEEL CASTING PROCESS Scott D. Roser, Graduate Student David A. Long, Associate Professor Department of Civil Engineering Pennsylvania State University University Park, Pennsylvania 16802 Jeffrey A. Vaughn, Staff Engineer CH2MHill Denver, Colorado 80222 Carpenter Technology Corporation (Cartech) of Reading, Pennsylvania, operates a stainless steel continuous casting machine which was designed, installed and commissioned by Concast, Inc. of Montvale, New Jersey. The continuous casting of steel is a metallurgical process in which molten steel is converted into semifinished shapes which then are reheated and converted by reduction mills into finished products. The conversion of molten steel to semifinished shapes involves the controlled cooling of the steel by water sprays. Spray cooling in the continuous casting process requires that water be applied to the surface of the steel at precise rates to achieve uniform cooling. This cooling water cascades down over the machine picking up mill scale, oil, grease and dirt, and is collected in a sump. The sump discharges into a clarifier where a dragout scraper removes the settleable solids. The cooling water, which contains mostly iron, chromium, nickel and other metal oxides, then is pumped through two downflow pressure sand filters, operating in parallel, with a third filter for stand-by use. The two filters currently are operated as constant rate filters at a hydraulic loading rate of 5 gpm/ft2 (204 1/min-m2). Constant-rate filtration is controlled by orifice plates. The filtered water either is passed through a cooling tower and stored in a cold well to be used again as quenching water or it is recirculated into the clarifier. This routing would depend on the quantity of water in the cold well which in turn is dependent on the amount of casting which takes place during any period of time. The water system is a closed system except for additions to make up for evaporation losses. The filters are backwashed when headloss through the filter reaches 6 psi(41.3 kN/m2). In addition, the backwashing is sequenced such that after a filter is backwashed it is put on stand-by. During backwash, filter effluent is passed up through the filter media and out into a cone-shaped surge tank in which the solids settle out and the supernatant is allowed to flow back into the clarifier. The resulting sludge later is hauled to a proper disposal site. Figure 1 shows a schematic of the spray and cooling water system. Each year Cartech undergoes a plant shutdown in August for overhaul and replacement of various equipment throughout the plant. For the purposes of the phase 1 portion of the study, it was of interest to Cartech personnel as to whether they should replace the existing sand medium in the pressure filters with new sand, keep the old sand medium which had been in place for about 2 years, or replace the sand with a different medium that would yield better effluent quality. In view of this concern, the supplier of the pressure filters, Roberts Filter Manufacturing Company, proposed to install a pilot plant unit to determine a more optimum combination(s) of hydraulic loading rate and media for this particular application. The conclusions of the phase 1 study would be used by Cartech to determine what should be done with their existing sand medium during the plant shutdown and also be of use to Roberts Filter for similar future applications. 691
Object Description
Purdue Identification Number | ETRIWC198272 |
Title | Optimization of secondary cooling water filtration in a continuous stainless steel casting process |
Author |
Roser, Scott D. Long, David A. Vaughn, Jeffrey A. |
Date of Original | 1982 |
Conference Title | Proceedings of the 37th Industrial Waste Conference |
Extent of Original | p. 691-708 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-14 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 691 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | OPTIMIZATION OF SECONDARY COOLING WATER FILTRATION IN A CONTINUOUS STAINLESS STEEL CASTING PROCESS Scott D. Roser, Graduate Student David A. Long, Associate Professor Department of Civil Engineering Pennsylvania State University University Park, Pennsylvania 16802 Jeffrey A. Vaughn, Staff Engineer CH2MHill Denver, Colorado 80222 Carpenter Technology Corporation (Cartech) of Reading, Pennsylvania, operates a stainless steel continuous casting machine which was designed, installed and commissioned by Concast, Inc. of Montvale, New Jersey. The continuous casting of steel is a metallurgical process in which molten steel is converted into semifinished shapes which then are reheated and converted by reduction mills into finished products. The conversion of molten steel to semifinished shapes involves the controlled cooling of the steel by water sprays. Spray cooling in the continuous casting process requires that water be applied to the surface of the steel at precise rates to achieve uniform cooling. This cooling water cascades down over the machine picking up mill scale, oil, grease and dirt, and is collected in a sump. The sump discharges into a clarifier where a dragout scraper removes the settleable solids. The cooling water, which contains mostly iron, chromium, nickel and other metal oxides, then is pumped through two downflow pressure sand filters, operating in parallel, with a third filter for stand-by use. The two filters currently are operated as constant rate filters at a hydraulic loading rate of 5 gpm/ft2 (204 1/min-m2). Constant-rate filtration is controlled by orifice plates. The filtered water either is passed through a cooling tower and stored in a cold well to be used again as quenching water or it is recirculated into the clarifier. This routing would depend on the quantity of water in the cold well which in turn is dependent on the amount of casting which takes place during any period of time. The water system is a closed system except for additions to make up for evaporation losses. The filters are backwashed when headloss through the filter reaches 6 psi(41.3 kN/m2). In addition, the backwashing is sequenced such that after a filter is backwashed it is put on stand-by. During backwash, filter effluent is passed up through the filter media and out into a cone-shaped surge tank in which the solids settle out and the supernatant is allowed to flow back into the clarifier. The resulting sludge later is hauled to a proper disposal site. Figure 1 shows a schematic of the spray and cooling water system. Each year Cartech undergoes a plant shutdown in August for overhaul and replacement of various equipment throughout the plant. For the purposes of the phase 1 portion of the study, it was of interest to Cartech personnel as to whether they should replace the existing sand medium in the pressure filters with new sand, keep the old sand medium which had been in place for about 2 years, or replace the sand with a different medium that would yield better effluent quality. In view of this concern, the supplier of the pressure filters, Roberts Filter Manufacturing Company, proposed to install a pilot plant unit to determine a more optimum combination(s) of hydraulic loading rate and media for this particular application. The conclusions of the phase 1 study would be used by Cartech to determine what should be done with their existing sand medium during the plant shutdown and also be of use to Roberts Filter for similar future applications. 691 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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