Application of Pulsed Spark Discharge for Mitigation of Mineral Fouling in a Heat Exchanger

2010 ◽  
Author(s):  
Yong Yang ◽  
Hyoungsup Kim ◽  
Jin M. Jung ◽  
Alexander Fridman ◽  
Young I. Cho
Keyword(s):  
Heat Exchanger ◽  
Calcium Carbonate ◽  
Pure Water ◽  
Cooling Water ◽  
Calcium Content ◽  
Hard Water ◽  
Spark Discharge ◽  
Mineral Contents ◽  
Mineral Fouling ◽  
Pulsed Spark Discharge

One of the challenges in the production of electricity is the cooling water management because the calcium content in circulating cooling water continues to increase with time as pure water evaporates. Thus, the excessive mineral contents in water circulation systems could cause severe fouling in heat transfer equipment. To avoid the catastrophic failure in condensers, the cooling water is discharged after 3 cycles at a rate of 10 million gallons a day in a 1,000-MW thermoelectric power plant. The present study investigated the effect of pulsed spark discharges on the mitigation of mineral fouling in a concentric counterflow heat exchanger. Artificial hard water with calcium carbonate hardness ranging from 250 to 500 ppm was used with velocity varying over a range of 0.1–0.5 m/s and zero blowdown. Fouling resistances decreased by 50–88% for the plasma treated cases compared with the values for no-treatment cases. SEM photographs showed particle with larger sizes for the plasma treated cases comparing to smaller but more organized particles for the no-treatment cases. The different structures of particles were associated with pulsed spark discharge assisted precipitation of calcium carbonate in oversaturated hard water. X-ray diffraction data showed calcite crystal structures for all cases.

Mineral Fouling Control by Underwater Plasma Discharge in a Heat Exchanger

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Yong Yang ◽  
Hyoungsup Kim ◽  
Alexander Fridman ◽  
Young I. Cho
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Hard Water ◽  
Plasma Discharge ◽  
Mineral Contents ◽  
Fouling Control ◽  
Spark Discharges ◽  
Mineral Fouling ◽  
Pulsed Spark Discharge ◽  
Heat Exchanger Surface

The excessive mineral contents in water circulation systems could cause severe fouling in heat transfer equipment. The present study investigated the effect of underwater pulsed spark discharges on the mitigation of mineral fouling in a concentric counterflow heat exchanger. Artificial hard water with calcium carbonate hardness of 250 mg/L was used with velocity ranging from 0.1 m/s to 0.5 m/s and zero blowdown. Fouling resistances decreased by 50–72% for the plasma treated cases compared with the values for no-treatment cases, indicating that the pulsed spark discharge could significantly mitigate the mineral fouling on the heat exchanger surface.

Application of pulsed spark discharge for calcium carbonate precipitation in hard water

2010 ◽  
Vol 44 (12) ◽  
pp. 3659-3668 ◽  
Author(s):  
Yong Yang ◽  
Hyoungsup Kim ◽  
Andrey Starikovskiy ◽  
Alexander Fridman ◽  
Young I. Cho
Keyword(s):  
Calcium Carbonate ◽  
Hard Water ◽  
Spark Discharge ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Pulsed Spark Discharge

Fouling and fouling mitigation of calcium compounds on heat exchangers by novel colloids and surface modifications

2020 ◽  
Vol 36 (6) ◽  
pp. 653-685 ◽  
Author(s):  
Salim N. Kazi
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Whey Proteins ◽  
Natural Fibers ◽  
Cooling Water ◽  
Hard Water ◽  
Mineral Salts ◽  
Salt Crystals ◽  
Mineral Fouling ◽  
Living Organisms

AbstractFouling is the accumulation of unwanted materials on surfaces that causes detrimental effects on its function. The accumulated materials can be composed of living organisms (biofouling), nonliving substances (inorganic and/or organic), or a combination of both of them. Mineral fouling occurs when a process uses cooling water supersaturated with mineral salt crystals (i.e. hard water). Precipitation ensues on heat transfer surfaces whenever the inversely soluble dissolved calcium salt ions are exposed to high temperature. Mineral salts, dirt, waxes, biofilms, whey proteins, etc. are common deposits on the heat exchanger surfaces, and they create thermal resistance and increase pressure drop and maintenance costs of plants. Fouling of dissolved salts and its mitigation have been studied in detail by varying process parameters, surface materials, coatings on surfaces, additives, etc. by many researchers. In the present stage, researchers have considered polymeric additives, environmental friendly nanoparticles, natural fibers, and thermal conductive coatings (metallic and polymeric) in the study of mitigation of fouling. A better understanding of the problem and the mechanisms that lead to the accumulation of deposits on surfaces will provide opportunities to reduce or even eliminate the problem in certain situations. The present review study has focused on fouling phenomena, environment of fouling, heat exchanger fouling in design, and mitigation of fouling. The findings could support in developing the improved heat exchanger material surfaces, retain efficiency of the heat exchangers, and prolong their continuous operation.

Removal of Calcium Carbonate Build-Up in Condenser Tubes Restores Efficiency

2017 ◽  
Author(s):  
Larry (Irv) Iervoline
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Calcium Carbonate ◽  
Transfer Rate ◽  
Cooling Water ◽  
Hard Water ◽  
The United States ◽  
Power Station ◽  
Scale Deposits ◽  
Mechanical Cleaning

Water is essential to the power generation process, and for many power generation plants that rely on cooling water systems to condense steam, total hardness in source water is a problem. The high mineral content in many sources of cooling water results in hardened, calcified scale deposits forming on the walls of condenser tubes. These deposits form an insulation barrier inhibiting heat transfer. The scale also reduces the inner diameter of the tubes, restricting the flow of cooling water and further reducing heat transfer. As the heat transfer rate falls, performance of the condenser degrades, which can lead to decreasing megawatt output of the plant. A power station in the United States sources hard lakewater for cooling. Like many plants utilizing hard water, the station relies on a water treatment program to control the formation of hard scale deposits. However, when the plant opened a closed cooling water exchanger (CCW) in its Unit 1, a layer of calcium carbonate was found on the tube walls throughout the bundle. The CCW exchanger was shot with a variety of mechanical cleaners to thoroughly remove the scale and other deposits and debris from the tubes. Plant management suspected that the same problem might be occurring in the main condenser, and they understood that if scale was forming inside the condenser, the resulting loss in heat transfer rate would be a contributing factor in the decreased efficiency of the unit. Since the plant was planning an eddy current test on 100% of the more than 12,000 stainless steel tubes in the main condenser, the tubes were required to be thoroughly cleaned. Upon opening the main condenser, technicians verified the presence of calcium carbonate fouling, confirming their suspicions. While not knowing the condition of the tubes underneath the deposit, plant engineers were concerned about the underlying tube condition. They were also looking for alternative cleaning methods to provide relief from environmental concerns often associated with chemical cleaning. To preserve tube integrity and assure thorough removal of deposits, the plant decided to clean the condenser tubes utilizing the same mechanical cleaning method as the CCW unit. The condenser tubes would be shot with a series of specialized mechanical tube cleaners, one designed to fracture the calcium carbonate and a second designed to remove the fractured scale and other deposits from the tubes. This paper highlights the role of hard water in condenser tube fouling, the need to remove scale from condenser tubes and the mechanical cleaning process that was used to restore condenser performance at a prototypical coal fired power station in the United States.

Determination of Pressure Drop of Pure Water Flowing Upward Direction in a Double Tube Heat Exchanger Having Smooth and Microfin Tubes

2014 ◽  
Author(s):  
Alican Çebi ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
Mustafa Kemal Sevindir ◽  
Somchai Wongwises
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Friction Factor ◽  
Test Section ◽  
Pure Water ◽  
Cooling Water ◽  
Tube Heat Exchanger ◽  
Upward Direction ◽  
Microfin Tubes

Single phase friction factor and pressure drop behavior of smooth and microfin tubes are studied experimentally. The vertical test section was working as a counter flow double tube heat exchanger with water flowing in the inner smooth and microfin tubes having varying inner diameters and cooling water flowing in the annulus. Pressure drop of water due to cooling in upward flow in inner tubes is determined by experiments. Inner tube mass flow rate was between 0.023 kg/s to 0.100 kg/s while test section inlet temperatures were 40°C and 60°C. Effect of Reynolds number on pressure drop is also investigated and Blasius type friction factor correlations are developed for both smooth and microfin tubes.

Experimental study on calcium carbonate precipitation using electromagnetic field treatment

2013 ◽  
Vol 67 (12) ◽  
pp. 2784-2790 ◽  
Author(s):  
Miao Xuefei ◽  
Xiong Lan ◽  
Chen Jiapeng ◽  
Yang Zikang ◽  
He Wei
Keyword(s):  
Crystal Structure ◽  
Experimental Study ◽  
Calcium Carbonate ◽  
Electromagnetic Fields ◽  
Cooling Water ◽  
Hard Water ◽  
Carbonate Precipitation ◽  
Constant Flow ◽  
Calcium Carbonate Precipitation ◽  
Electric Pulses

The present study investigated the effectiveness of electromagnetic fields in preventing calcium carbonate (CaCO3) fouling in cooling water. Four different frequencies and two different voltages were adopted to induce electromagnetic fields directly in water with constant water temperature and constant flow velocity. Artificial hard water was used. The solution conductivities decreased by 17–25% from their initial values in the electromagnetic anti-fouling treatment (EAT) cases, depending on different frequencies of electric pulses, whereas the untreated case dropped by 31%. The particle size became small and the crystal structure changed into loose style after EAT. The EAT device independently developed by the State Key Laboratory had been validated as an effective apparatus in preventing CaCO3 fouling in cooling water.

Transjøen, a Groundwater Influenced Lake with Special Redox and Sulphate Conditions

1976 ◽  
Vol 7 (5) ◽  
pp. 307-320 ◽  
Author(s):  
G. S. Bremmeng ◽  
A. E. Kloster
Keyword(s):  
Calcium Carbonate ◽  
Chemical Composition ◽  
Lower Layer ◽  
Calcium Content ◽  
Meromictic Lake ◽  
Redox Potentials ◽  
Precipitated Calcium Carbonate

Transjøen, a lake in S.E. Norway investigated hydrographically from October 1969 to October 1971, consists of two basins, both of which are meromictic (lake with lower layer which does not participate in the periodic circulations). The lake has a large influx of groundwater of very varying chemical composition. The calcium content is high and precipitated calcium carbonate and electrolyte rich groundwater is assumed to be the main reason for the meromictic stability. The redox potentials of monimolimnion (the lower layer which does not participtate in the periodic circulation) are extremely low, but in spite of this fact the content of sulphate is high.

Scaling of Heat Exchanger Tubes by Calcium Carbonate

1975 ◽  
Vol 97 (4) ◽  
pp. 504-508 ◽  
Author(s):  
A. P. Watkinson ◽  
O. Martinez
Keyword(s):  
Heat Exchanger ◽  
Calcium Carbonate ◽  
Mathematical Models ◽  
Flow Velocity ◽  
Test Section ◽  
Suspended Solids ◽  
Bulk Temperature ◽  
Fouling Resistance ◽  
Steam Temperature ◽  
Scaling Process

Scaling of copper heat exchanger tubes has been studied under conditions that promote rapid and severe scaling. Artificially hardened water of high dissolved and suspended solids is recirculated through a heated test section operated at constant steam temperature. The effects of flow velocity, tube diameter, and bulk temperature on the asymptotic fouling resistance have been determined. Results are interpreted in terms of mathematical models of the scaling process.

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