Scr Cleaning Report
Unit 1 SCR Cleaning Report Fall 2011
10/24/2011 The Thomas Hill Unit 1 SCR consists of three layers of 1150 mm length Ceram catalyst with 45 modules per layer. Catatlyst cleaning by SCR Services, Inc. was performed in this SCR for four 12 hour shifts starting on 10/22/11with a six man crew per shift. A vacuum hose, an air lance, and a pneumatic vibrator were employed in the process. The vibrator was only used on the top two layers because access was not available to place the vibrator below the third level. Furthermore only limited cleaning was performed on the third layer due to the time limitation placed upon the contractor in order to kept the cleaning costs within the amount of the purchase order. The contractor project manager indicated that with sufficient time improved cleaning could have been realized. The estimated average plugging per layer before and after this cleaning effort are given below. Charts indicating plugging across each layer are also presented below. Prior to SCR Services’ work the catalyst had been vacuumed by AECI personnel. SCR Services appears to have reduced the plugging in layers 1 and 2 around 50% and in layer 3 around 20%. While one of the greatest indicators of plugging removal will be the decrease in layer differential pressures, we will not have any data on this until the SCR is placed back into service int January 2012.
Table 1 Unit 1 SCR plugging layer averages before and after SCR Services’ 48 hour cleaning efforts Before Layer 1 Layer 2 Layer 3 34% 26% 26% After 17% 12% 20%
Report prepared by Tom Salt, 10/24/2011
10/24/2011 The Thomas Hill Unit 1 SCR consists of three layers of 1150 mm length Ceram catalyst with 45 modules per layer. Catatlyst cleaning by SCR Services, Inc. was performed in this SCR for four 12 hour shifts starting on 10/22/11with a six man crew per shift. A vacuum hose, an air lance, and a pneumatic vibrator were employed in the process. The vibrator was only used on the top two layers because access was not available to place the vibrator below the third level. Furthermore only limited cleaning was performed on the third layer due to the time limitation placed upon the contractor in order to kept the cleaning costs within the amount of the purchase order. The contractor project manager indicated that with sufficient time improved cleaning could have been realized. The estimated average plugging per layer before and after this cleaning effort are given below. Charts indicating plugging across each layer are also presented below. Prior to SCR Services’ work the catalyst had been vacuumed by AECI personnel. SCR Services appears to have reduced the plugging in layers 1 and 2 around 50% and in layer 3 around 20%. While one of the greatest indicators of plugging removal will be the decrease in layer differential pressures, we will not have any data on this until the SCR is placed back into service int January 2012.
Table 1 Unit 1 SCR plugging layer averages before and after SCR Services’ 48 hour cleaning efforts Before Layer 1 Layer 2 Layer 3 34% 26% 26% After 17% 12% 20%
Report prepared by Tom Salt, 10/24/2011