Thursday, October 25, 2012
Water Analysis: Hongqiao, China
Make up 8.0 CoC
Conductivity 304 2432
pH 7.6 8.7
Ca Hardness 55.5 444
Alkalinity 73 584
Chloride 28 224
Total Hardness 111 888
Silica 5.5 44
Predicted LSI 2.4
This make up water sample from Hongqiao China was sampled and analyzed for use in a cooling tower application. By using the Langelier Saturation Index (LSI) we can predict the scale forming tendency of the water. Modern water treatment chemistry can prevent scale in waters with a LSI of 2.3-2.5. In waters with a pH greater than 8.5 that contain silica and magnesium hardness a mineral scale problem could occur. Under the right conditions Magnesium Silicate will form. This scale is a barrier to heat transfer and is one of the most difficult scales to remove. Silica levels are typically not a concern below 150ppm and can be handled as high as 200ppm with proper chemistry.
We can see from the above calculation that this tower can be operated safely at 8.0 Cycles of Concentration (CoC). At 8.0 CoC the water will have an LSI of 2.4 with a silica level of 44ppm. Both levels are within the acceptable range of modern water treatment chemistry. It is important to note that at a LSI of 2.4 the water is extremely scale forming. If the proper amount of water treatment chemical is not maintained at ALL times the system will rapidly develop scale. Many facilities in Asia do not utilize modern chemical feed and control equipment. Instead they manually dose chemical and control bleed valves. It is not possible to maintain tight enough control with manual methods to achieve the water savings possible at 8.0 CoC without eventually forming scale. For this reason an automated chemical feed and control system must be installed.
Why does this information matter? Higher CoC results in lower water and chemical consumption. Consider a 1,000 ton (RT) tower operating 24 hours a day, 365 days per year at full load. By increasing tower cycles from 1.0 to 8.0 cooling tower make up is reduced by 1,611,938 liters (425,829 gallons) per day! This significant savings can easily be realized with a sound water treatment program and routine monitoring.
Wednesday, October 24, 2012
Water Analysis: Bali, Indonesia
Make up 3.5 CoC
Conductivity 1033 3615
pH 7.9 8.8
Ca Hardness 102.5 358.7
Alkalinity 176 616
Chloride 173 605.5
Total Hardness 205 717.5
Silica 26 91
Predicted LSI 2.4
This make up water sample from Bali Indonesia was sampled and analyzed for use in a cooling tower application. By using the Langelier Saturation Index (LSI) we can predict the scale forming tendency of the water. Modern water treatment chemistry can prevent scale in waters with a LSI of 2.3-2.5. In waters with a pH greater than 8.5 that contain silica and magnesium hardness a mineral scale problem could occur. Under the right conditions Magnesium Silicate will form. This scale is a barrier to heat transfer and is one of the most difficult scales to remove. Silica levels are typically not a concern below 150ppm and can be handled as high as 200ppm with proper chemistry.
We can see from the above calculation that this tower can be operated safely at 3.5 Cycles of Concentration (CoC). At 3.5 CoC the water will have an LSI of 2.4 with a silica level of 91ppm. Both levels are within the acceptable range of modern water treatment chemistry. It is important to note that at a LSI of 2.4 the water is extremely scale forming. If the proper amount of water treatment chemical is not maintained at ALL times the system will rapidly develop scale. Many facilities in Indonesia do not utilize modern chemical feed and control equipment. Instead they manually dose chemical and control bleed valves. It is not possible to maintain tight enough control with manual methods to achieve the water savings possible at 3.5 CoC without eventually forming scale. For this reason an automated chemical feed and control system must be installed.
Why does this information matter? Higher CoC results in lower water and chemical consumption. Consider a 1,000 ton (RT) tower operating 24 hours a day, 365 days per year at full load. By increasing tower cycles from 1.0 to 3.5 cooling tower make up is reduced by 573,008,400 liters (151,372,800 gallons) per year! This significant savings can easily be realized with a sound water treatment program and routine monitoring.
Conductivity 1033 3615
pH 7.9 8.8
Ca Hardness 102.5 358.7
Alkalinity 176 616
Chloride 173 605.5
Total Hardness 205 717.5
Silica 26 91
Predicted LSI 2.4
This make up water sample from Bali Indonesia was sampled and analyzed for use in a cooling tower application. By using the Langelier Saturation Index (LSI) we can predict the scale forming tendency of the water. Modern water treatment chemistry can prevent scale in waters with a LSI of 2.3-2.5. In waters with a pH greater than 8.5 that contain silica and magnesium hardness a mineral scale problem could occur. Under the right conditions Magnesium Silicate will form. This scale is a barrier to heat transfer and is one of the most difficult scales to remove. Silica levels are typically not a concern below 150ppm and can be handled as high as 200ppm with proper chemistry.
We can see from the above calculation that this tower can be operated safely at 3.5 Cycles of Concentration (CoC). At 3.5 CoC the water will have an LSI of 2.4 with a silica level of 91ppm. Both levels are within the acceptable range of modern water treatment chemistry. It is important to note that at a LSI of 2.4 the water is extremely scale forming. If the proper amount of water treatment chemical is not maintained at ALL times the system will rapidly develop scale. Many facilities in Indonesia do not utilize modern chemical feed and control equipment. Instead they manually dose chemical and control bleed valves. It is not possible to maintain tight enough control with manual methods to achieve the water savings possible at 3.5 CoC without eventually forming scale. For this reason an automated chemical feed and control system must be installed.
Why does this information matter? Higher CoC results in lower water and chemical consumption. Consider a 1,000 ton (RT) tower operating 24 hours a day, 365 days per year at full load. By increasing tower cycles from 1.0 to 3.5 cooling tower make up is reduced by 573,008,400 liters (151,372,800 gallons) per year! This significant savings can easily be realized with a sound water treatment program and routine monitoring.
Water Analysis: Chennai, India
Make up 3.0 CoC
Conductivity 1192 3576
pH 7.4 8.6
Ca Hardness 138.5 415.5
Alkalinity 182 546
Chloride 178 534
Total Hardness 277 1108
Silica 28.9 86.7
Predicted LSI 2.3
This make up water sample from Chennai India was sampled and analyzed for use in a cooling tower application. By using the Langelier Saturation Index (LSI) we can predict the scale forming tendency of the water. Modern water treatment chemistry can prevent scale in waters with a LSI of 2.3-2.5. In waters with a pH greater than 8.5 that contain silica and magnesium hardness a mineral scale problem could occur. Under the right conditions Magnesium Silicate will form. This scale is a barrier to heat transfer and is one of the most difficult scales to remove. Silica levels are typically not a concern below 150ppm and can be handled as high as 200ppm with proper chemistry.
We can see from the above calculation that this tower can be operated safely at 3.0 Cycles of Concentration (CoC). At 3.0 CoC the water will have an LSI of 2.3 with a silica level of 86ppm. Both levels are within the acceptable range of modern water treatment chemistry. It is important to note that at a LSI of 2.3 the water is extremely scale forming. If the proper amount of water treatment chemical is not maintained at ALL times the system will rapidly develop scale. Many facilities in India do not utilize modern chemical feed and control equipment. Instead they manually dose chemical and control bleed valves. It is not possible to maintain tight enough control with manual methods to achieve the water savings possible at 3.0 CoC without eventually forming scale. For this reason an automated chemical feed and control system must be installed.
Why does this information matter? Higher CoC results in lower water and chemical consumption. Consider a 1,000 ton (RT) tower operating 24 hours a day, 365 days per year at full load. By increasing tower cycles from 1.0 to 3.0 cooling tower make up is reduced by 567,039,500 liters (149,796,000 gallons) per year! This significant savings can easily be realized with a sound water treatment program and routine monitoring.
Wednesday, April 18, 2012
Corrosion Cell
Corrosion is a never ending battle in the water treatment industry. It is an electrochemical process in which a difference in electrical potential develops between two metals or between differeing parts of a single metal. Electrons flow from the anode to the cathode. Metal ions go into solution at the anode causing metal loss (corrosion). The speed at which the ions go into solution can be increased with higher conductivity waters (sea water, cooling water, boiler water). There are many types of corrosion and many more ways to control it. Having a basic understanding of the process will enable you to better choose a treatment option best suited for the application.
Wednesday, February 29, 2012
ASHRAE Project Number 1361-RP
The topic of Non Chemical Device (NCD) water treatment seems to always be popular. ASHRAE Project Number 1361-RP focused on Biological Control in Cooling Water Systems using Non-Chemical Treatment Devices. Five different NCD devices were analyzed in the study from the following categories: Magnetic, Pulsed Electric Field, Electrostatic, Ultrasonic, and Hydrodynamic Cavitation.
The experiment concluded, "...no statistically significant difference...in planktonic or sessile microbial concentrations (HPC) was observed between the control tower and a tower treated by any of the five NCDs evaluated in this study...", (i-ii).
You can download the entire report here: http://rp.ashrae.biz/page/ASHRAE-D-1361-RP-20101005.pdf
The experiment concluded, "...no statistically significant difference...in planktonic or sessile microbial concentrations (HPC) was observed between the control tower and a tower treated by any of the five NCDs evaluated in this study...", (i-ii).
You can download the entire report here: http://rp.ashrae.biz/page/ASHRAE-D-1361-RP-20101005.pdf
Water Treatment Case Study: Low Cycles of Concentration (CoC)
Size: 800 Ton Tower
Load: 90% Summer; 30% Winter
Location: Tokyo, Japan
Problem Description: The tower achieved target operating cycles of concentration (CoC) of 7.0 during the summer months. During the winter it was hard to achieve a CoC of >5.0.
Assumption: Cooler temperatures did not enable enough evaporation for tower to “Cycle Up”.
Finding: The calculated summer blowdown rate is 3.6 gallons per minute (GPM) @ 90% load. The calculated winter blowdown rate is 1.2 GPM @ 30% load. Upon inspection a condenser water pump was found with a badly leaking seal (see photo). An impromptu field test was conducted to measure the amount of water being lost through the seal leak. Using a sample bottle to capture the water loss from the pump and a watch to calculate the time it took to fill the bottle it was estimated that just under 2.0 GPM were being lost at the seal.
Conclusion: Water loss through a seal leak has the same effect on a tower that excessive blowdown does. Since the leak rate of 2.0 GPM exceeds the winter blowdown rate of 1.2 GPM it is not possible to achieve the results desired. This problem was not noticed in the summer because the summer blowdown rate of 3.6 GPM exceeds the leak rate of 2.0 GPM.
Load: 90% Summer; 30% Winter
Location: Tokyo, Japan
Problem Description: The tower achieved target operating cycles of concentration (CoC) of 7.0 during the summer months. During the winter it was hard to achieve a CoC of >5.0.
Assumption: Cooler temperatures did not enable enough evaporation for tower to “Cycle Up”.
Finding: The calculated summer blowdown rate is 3.6 gallons per minute (GPM) @ 90% load. The calculated winter blowdown rate is 1.2 GPM @ 30% load. Upon inspection a condenser water pump was found with a badly leaking seal (see photo). An impromptu field test was conducted to measure the amount of water being lost through the seal leak. Using a sample bottle to capture the water loss from the pump and a watch to calculate the time it took to fill the bottle it was estimated that just under 2.0 GPM were being lost at the seal.
Conclusion: Water loss through a seal leak has the same effect on a tower that excessive blowdown does. Since the leak rate of 2.0 GPM exceeds the winter blowdown rate of 1.2 GPM it is not possible to achieve the results desired. This problem was not noticed in the summer because the summer blowdown rate of 3.6 GPM exceeds the leak rate of 2.0 GPM.
Recommendation: Repair seal
Saturday, February 11, 2012
Chiller Inspection
When is the best time of year for selling cooling tower water treatment? It is during the winter months. During the cooler season many clients will begin to do their preventative maintenance on Chillers, Cooling Towers, and Heat Exchangers. It is during this maintenance period that the effects of water treatment will become apparent. When a chiller is opened up for an inspection you want to be there to give your professional opinion. Having a boroscope, digital camera, and a flashlight will assit you in making a quality inspection.
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