EP0817947A1 - Process for increasing cooling tower's thermal capability - Google Patents
Process for increasing cooling tower's thermal capabilityInfo
- Publication number
- EP0817947A1 EP0817947A1 EP96911516A EP96911516A EP0817947A1 EP 0817947 A1 EP0817947 A1 EP 0817947A1 EP 96911516 A EP96911516 A EP 96911516A EP 96911516 A EP96911516 A EP 96911516A EP 0817947 A1 EP0817947 A1 EP 0817947A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cooling tower
- nonionic surfactant
- ppm
- water
- cooling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F25/00—Component parts of trickle coolers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/40—Mixing liquids with liquids; Emulsifying
- B01F23/45—Mixing liquids with liquids; Emulsifying using flow mixing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S261/00—Gas and liquid contact apparatus
- Y10S261/11—Cooling towers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S261/00—Gas and liquid contact apparatus
- Y10S261/46—Residue prevention in humidifiers and air conditioners
Definitions
- the invention is a process for increasing the system thermal capability of cooling tower, preferably a splash filled cooling tower where water is circulated and splashed against splash bars during the cooling process.
- the process comprises contacting the tower circulating water with a nonionic surfactant composition in an amount effective to increase the system thermal capability of the cooling tower.
- cooling towers are used in many industrial processes, power generating plants are of particular interest because of the magnitude of the heat produced and effect of cooling water on process efficiency. These plants are typically powered by steam which is generated to turn turbines. Turbines operate by passing expanding steam through a series of nozzles which are designed to convert the energy of expansion directly into rotational motion. The rotational motion causes an electromagnetic generator to generate electricity on a commercial scale. The steam generated to turn the turbine may be generated by the combustion of fossil fuels or nuclear power. The turbine exit steam generated must be cooled and condensed to water which is recycled to generate more steam. The condensation process occurs in a condensing heat exchanger where heat from the steam is transferred to cooler circulating water. The now heated circulating water is pumped to a cooling tower to be cooled and then recycled back to the condensing heat exchanger.
- the water to be cooled in the cooling tower is circulated and distributed in direct contact with cooler air which is circulated by mechanical fans or natural convection. Air flow may be across the cascading liquid or counter current.
- the cooling tower consists of an enclosure which contains a hot water distribution system, a set of louvers or baffles (fill) for breaking the water into small films and droplets, and a cooled water collection basin.
- a hot water distribution system a set of louvers or baffles (fill) for breaking the water into small films and droplets
- a cooled water collection basin a set of louvers or baffles (fill) for breaking the water into small films and droplets.
- a cooled water collection basin There are several internal gridwork arrangements, all designed to enhance water splashing and film formation.
- cooling towers There are many types of manufactured cooling towers including mechanically induced and naturally induced draft towers, crossflow and counterflow towers, wet/dry plume abatement towers, and water conservation towers.
- the invention is a process for increasing the system thermal capability of a cooling tower comprising: contacting the circulating water in the cooling tower with a nonionic surfactant composition in an amount effective to increase the system thermal capability of said cooling tower, said nonionic surfactant composition comprising at least one nonionic surfactant having the following characteristics: (a) a hydrophobic segment; and (b) a hydrophilic segment derived from 2 to 15 moles derived from a polyalkylene oxide ether, such that the average HLB of the nonionic surfactant composition is from 9-12.
- An increase in the system thermal capability of the cooling tower indicates that more efficient absorption of heat by the cooling air is taking place.
- Figure 1 is a schematic view of a splash filled cooling tower with the arrows showing the direction of air flow and water flow.
- Figure 2 is a transverse cross section of splash filled cooling tower.
- Figures 3-6 are graphs which show the effect on cooling tower thermal capability when several nonionic surfactants are added to the basin of the cooling tower.
- Figure 1 is a schematic view of a splash filled cooling tower 55'-60' in height with arrows showing water inlet 1, water outlet 2, airflow with directional arrows, water flow with directional arrows, and concrete basin 3 near pump where chemicals were fed into the cooling tower.
- Figure 2 is a transverse cross section of the splash filled cooling tower showing diffusion decks 4, splash bars 5, air inlet, louvers 6, and perimeter anchorage 7.
- FIGS 3-6 are graphs which plot cooling water (CWT) , thermal capacity, and wet bulb temperature (WBT)on the " ..../ axis against time on the "x" axis. Each graph shows that the thermal capacity of the cooling tower increased when three different nonionic surfactants were added to the cooling tower basin.
- CWT cooling water
- WBT wet bulb temperature
- Splash filled cooling towers use splash-type fill as the primary heat transfer surface.
- Splash-type fill is typically a succession of horizontal bars, "splash bars", which comprise the splash surface of the fill deck in a splash-filled cooling tower.
- Splash bars are usually flat or shaped to improve structural rigidity and/or heat transfer. Flat bars are sometimes referred to as “slats” or “lath”.
- slats or "lath”.
- Thermal efficiency of the cooling tower is related to an increase in the thermal capacity of the cooling tower.
- the thermal capability of a cooling tower is the ratio of the adjusted test circulating water rate to the predicted test circulating water rate at the test thermal conditions. This ratio is expressed as a percentage and can be expressed by the following formula:
- the nonionic surfactant composition used in this process have an average HLB value of 9-12. At least one nonionic surfactant in the nonionic surfactant composition must have a hydrophobic segment and a hydrophilic segment derived from 2 to 15 moles of polyoxyalkylene ether.
- the hydrophobic segment of the nonionic surfactant is derived from an aromatic hydrocarbon, or an aliphatic C10-C30 compound selected from the group consisting of saturated fatty acids, unsaturated fatty acids, saturated fatty acid alcohols, fatty triglycerides, and unsaturated fatty acid alcohols.
- the hydrophilic segment of the nonionic surfactant is preferably a polyalkylene ether derived from 2 to 15 mole ethylene oxide, preferably ethoxylated with from 4 to 10 moles of ethylene oxide.
- the nonionic surfactant is used in an effective amount.
- An effective amount of nonionic surfactant is an amount effective to increase the thermal capacity of the tower circulating water as measured by ASME Test Code PTC 23-1986, "Atmospheric Cooling Water Equipment", November 1986.
- the effective amount of nonionic surfactant needed is site specific and will depend upon the operating conditions of the cooling tower and the presence of other additives in the cooling tower such as defoamers, biocides, dyes, other surfactants, and dispersants in the cooling water.
- the effect of other additives will have greater effect when the nonionic surfactant used to increase thermal capability is chemically and/or physically interacting with the other additives. Such interaction may reduce the effect of the nonionic surfactant in increasing the thermal capability of the cooling tower.
- an effective amount of nonionic surfactant is a dosage of 1 ppm to 50 ppm every 1 to 5 hours, more typically from 1 ppm to 30 ppm, and, if circumstances are appropriate, most economically from 1 ppm to 10 ppm, where said amounts are based upon the amount of cooling water treated, and where said dosage is in addition to the amount of nonionic surfactant currently used or demanded for known functions of the cooling tower, such as a defoamer for a biocide.
- a defoamer for a biocide such as a defoamer for a biocide.
- the dosage is from 2 ppm to 6 ppm every 1 to 5 hours, most preferably from 2 ppm to 5 ppm every 2 to 5 hours, said ppm being based upon the amount of cooling water treated.
- nonionic surfactant In order to determine how much nonionic surfactant is needed to obtain an increase thermal capacity, it is suggested that gradual incremental amounts be added to the cooling tower. For instance, one can start by adding 1 ppm of nonionic surfactant to the cooling tower and monitoring for the next 1-2 hour period to determine if an increase in thermal capability is measured. If this amount is insufficient, then 2 ppm should be added and monitored for a one to two hour period. If 2 ppm is insufficient, then 3 ppm should be added and monitored for a one to two hour period. This procedure should be continued until an increase in thermal capability is observed or until it no longer makes economic sense to use a nonionic surfactant to increase thermal capability.
- the nonionic surfactant is added undiluted or as an aqueous dispersion to any reservoir in the cooling tower such as the sump or basin. It is convenient to add the nonionic surfactant to the basin near the pump section of the cooling tower.
- DECYL HEAVIES A complex mixture of alcohols, ethers, esters and other organic compounds sold by BASF Corporation under the product name "Heavy Oxo Ends” and the product number EP-290.
- the primary components of interest are C ⁇ 2 -C 2 _ (32- 38 weight percent) alcohols and C 2 ⁇ and higher alcohols (10-12 weight percent) .
- NS #1 100% polyethylene glycol 600 dioleate
- NS #2 A nonionic surfactant solution comprising decyl heavies (88.48 weight percent) , 15 mole ethoxylate of castor 10 oil having an HLB of 9.6 (2.3 weight percent) , 4 mole ethoxylate of lauryl alcohol (9.22 weight percent) having an HLB of 9.0.
- NS #3 A nonionic surfactant solution having an HLB of 9.3 comprising decyl heavies (76.1 weight percent), aluminum stearate (3.7 weight percent), hydrophobic silica (10.2), 15 mole
- an HLB of 9.4 comprising 2-ethyl hexanol bottoms which result from the distillation of 2-ethyl hexanol by the "oxo process" (88.5 weight percent), 15 mole ethoxylate of castor oil (2.30 30 weight percent) , 4 mole ethoxylate of lauryl alcohol (9.2 weight percent) .
- NS #5 A nonionic surfactant solution having an HLB of 9.2 comprising 2-ethyl hexanol bottoms (79.8 weight percent), 15 mole ethoxylate of castor oil (2.1 weight percent) , 4 mole ethoxylate of lauryl alcohol (8.3 weight percent), and hydrophobic silica (9.86 weight percent) .
- the cooling tower used in the examples was a Marley Tower Model 663-0-04 double flow, induced draft, cross flow, four cell splash filled cooling tower erected in a concrete basin.
- the hot water to the cooling tower came from process heat exchangers in a methanol plant having a flow rate of a 50,000 gallons per minute and a temperature of about 48°C.
- the nonionic surfactant was added to the water in the concrete basin near the pump section of the cooling tower as a bulk dose in an amount of about 2.5 ppm based upon the water treated.
- Example 1-5 the operating procedure of Control A was followed except various nonionic surfactants were added in the amount of 2.5 ppm, based upon the amount of water treated, to the basin of the cooling tower.
- the nonionic surfactants used are set forth in Table I which follows.
- the data in Table I indicate that the cooling tower thermal capability increased and the effluent temperature of the cooling tower dropped when the nonionic surfactants within the scope of this invention were added. This indicates that the cooling tower was operating more efficiently after the nonionic surfactant was added to the cooling tower water, i.e. the water in the tower system was cooled to a lower temperature after the non ionic surfactant was added.
- Figures 3-6 show a graphical picture of the effect of adding nonionic surfactants NS# 1, NS# 2, NS# 3, and NS # 5 to the cooling tower over a specified time. As these graphs show, a clear increase of the thermal capability of the cooling tower was observed shortly after each of the four nonionic surfactants were introduced. Depending upon the nonionic surfactant and the weather conditions, an increase in thermal capability was sustained for up to seven hours.
- the cooling tower was dosed with NS #1 at approximately 3:00 pm at a concentration of 5 ppm.
- the cold water temperature dropped continuously for the 35 minute period immediately after addition of the product for a total drop of about 1.1°F.
- the significant temperature drop was sustained for 2 to 3 hours with a return to pre-trial baseline temperature after 4-5 hours despite rising wet bulb temperatures.
- the cooling tower thermal capability was improved by 6.53% with the use of NS #1.
- the approach temperature (cwt-wbt) was reduced from 20.9°F to 19.5°F.
- the efficiency improvement in heat removed from the tower was approximately 417,000 Btu/min.
- the plant's monitoring equipment measured a decrease of 1°C in the effluent cooling water from 45°C to 44°C.
- the cooling tower was dosed with NS #2 at approximately 2:00 pm at a concentration of 5 ppm.
- the cold water temperature dropped a total of about 1.3°F.
- the effect was sustained for approximately 2 hours with a return to pre-trial baseline temperature after 4-5.
- the cooling tower thermal capability was improved by 7.2% with the use of NS #2.
- the approach temperature was reduced from 19.9°F to 18.5° F.
- the efficiency improvement in heat removed from the tower was approximately 542,000 Btu/min.
- the plant's monitoring equipment measured a decrease of 1°C in the effluent cooling water from 45°C to 44°C, as well as a 1°C decrease in process water from 33°C to 32°C.
- the data indicate that the subject process also improves plant productivity.
- a 1°F decrease in cold water temperature correlates into a 1% increase in methanol production.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Industrial Gases (AREA)
Abstract
Description
Claims
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/417,041 US5565019A (en) | 1995-04-04 | 1995-04-04 | Process for increasing the system thermal capability of a splash filled cooling tower |
US417041 | 1995-04-04 | ||
US08/623,555 US5853595A (en) | 1995-04-04 | 1996-03-28 | Process for increasing the system thermal capability of a splash filled cooling tower |
PCT/US1996/004450 WO1996031749A1 (en) | 1995-04-04 | 1996-03-28 | Process for increasing cooling tower's thermal capability |
1999-03-19 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0817947A1 true EP0817947A1 (en) | 1998-01-14 |
EP0817947A4 EP0817947A4 (en) | 1999-08-04 |
Family
ID=27023577
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96911516A Withdrawn EP0817947A4 (en) | 1995-04-04 | 1996-03-28 | Process for increasing cooling tower's thermal capability |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0817947A4 (en) |
CA (1) | CA2216379A1 (en) |
MX (1) | MX9707628A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7092171B2 (en) * | 2020-10-13 | 2022-06-28 | 栗田工業株式会社 | Circulating cooling water treatment method and cooling performance improvement method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3613779A (en) * | 1969-10-06 | 1971-10-19 | Clinton E Brown | Apparatus for obtaining high transfer rates in falling water film evaporators and condensers |
US4289581A (en) * | 1978-04-05 | 1981-09-15 | Katayama Chemical Works Co., Ltd. | Microbicidal slimicide compositions for industrial use |
US4954338A (en) * | 1987-08-05 | 1990-09-04 | Rohm And Haas Company | Microbicidal microemulsion |
US5037483A (en) * | 1990-01-30 | 1991-08-06 | Nalco Chemical Company | On-line iron clean-up |
EP0635564A1 (en) * | 1993-07-22 | 1995-01-25 | The Procter & Gamble Company | Stable liquid detergent compositions comprising dispersible silicone antifoam agent |
-
1996
- 1996-03-28 MX MX9707628A patent/MX9707628A/en unknown
- 1996-03-28 EP EP96911516A patent/EP0817947A4/en not_active Withdrawn
- 1996-03-28 CA CA002216379A patent/CA2216379A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3613779A (en) * | 1969-10-06 | 1971-10-19 | Clinton E Brown | Apparatus for obtaining high transfer rates in falling water film evaporators and condensers |
US4289581A (en) * | 1978-04-05 | 1981-09-15 | Katayama Chemical Works Co., Ltd. | Microbicidal slimicide compositions for industrial use |
US4954338A (en) * | 1987-08-05 | 1990-09-04 | Rohm And Haas Company | Microbicidal microemulsion |
US5037483A (en) * | 1990-01-30 | 1991-08-06 | Nalco Chemical Company | On-line iron clean-up |
EP0635564A1 (en) * | 1993-07-22 | 1995-01-25 | The Procter & Gamble Company | Stable liquid detergent compositions comprising dispersible silicone antifoam agent |
Non-Patent Citations (1)
Title |
---|
See also references of WO9631749A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP0817947A4 (en) | 1999-08-04 |
MX9707628A (en) | 1997-12-31 |
CA2216379A1 (en) | 1996-10-10 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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ITF | It: translation for a ep patent filed |
Owner name: DE DOMINICIS & MAYER S.R.L. |
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A4 | Supplementary search report drawn up and despatched |
Effective date: 19990621 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20010823 |