Patent Application
20120261437
The present disclosure relates to monitoring fuel storage tanks and, in particular, to a method and apparatus for preventing and detecting phase separation in fuel storage tanks.
Liquid storage tanks are widely relied upon to preserve and protect their contents. In particular, fuel storage tanks are an important part of the wider energy distribution system, and are routinely called upon to preserve liquid fuels during periods of storage while maintaining the fitness of the stored fuel for dispensation and use on short notice. Fuel storage tanks are commonly used, for example, to store gasoline at a gasoline filling station for distribution to end users (e.g., vehicle operators). Gasoline storage tanks are exposed to a wide variety of environmental conditions, and are often stored underground. Unintentional ingress of environmental moisture is a condition that can be encountered by these tanks.
Gasoline storage tanks often contain a blend of gasoline and alcohol, with blends having about 2.5 vol. % ethanol (“E-2.5”), 5 vol. % ethanol (“E-5”), or 10 vol. % ethanol (“E-10”) now commonly available as fuel for cars and trucks in the United States and abroad. Ethanol is a hygroscopic material, in that it attracts water from the air or from the surrounding environment. An excess amount of water in the gasoline/ethanol fuel blend will result in a condition known as phase separation. When phase separation occurs, excess alcohol, water and some constituents of the gasoline separate from the gasoline/ethanol fuel blend and form a new mixture (“phase separated fluid”) that is more dense than the gasoline/ethanol fuel blend but less dense than water. This phase separated fluid may comprise approximately 70 vol. % alcohol, 20 vol. % water, and 10 vol. % gasoline. If water infiltrates the storage tank quickly, it may settle at the bottom of the tank, below any phase separated fluid, without combining with the ethanol in the phase separated fluid or in the gasoline/ethanol fuel blend.
Dispenser pumps in fuel storage tanks are typically located near the bottom of the tank. If the phase separated fluid forms a thick enough layer at the bottom of the fuel storage tank, the phase separated fluid may be pumped into the tank of an end user, such as into an automobile gas tank. As a result, the automobile's engine may fail to start or may run poorly, and the phase separated fluid may have to be removed from the automobile's fuel system at substantial expense. If the water level becomes high enough to flow through the pump and into an automobile gas tank, significant damage to the automobile engine may result.
It would be desirable for a gasoline station operator to know whether phase separation and/or water ingress is occurring in the station's fuel storage tank. More particularly, it would be desirable for the gasoline station operator to know whether an alcohol/water/gasoline mixture resulting from the phase separation is at risk of forming or being pumped to a customer.
The present disclosure relates to a fuel delivery system and method for preventing and detecting phase separation in fuel storage tanks. Before phase separation occurs, the fuel delivery system may automatically warn a gas station operator to take preventative action. After phase separation occurs, the fuel delivery system may automatically shut down and warn the gas station operator to take corrective action.
According to an embodiment of the present disclosure, a fuel delivery system is provided including a storage tank containing a fuel product, the fuel product having a water content and a temperature, a fuel line in communication with the storage tank, a fuel dispenser in communication with the fuel line, the fuel dispenser being configured to dispense the fuel product to a customer, at least one monitor operatively positioned along the fuel line between the storage tank and the fuel dispenser, the at least one monitor collecting data indicative of the water content of the fuel product in the fuel line, and a controller in communication with the at least one monitor to receive collected data from the at least one monitor, the controller being programmed to automatically issue a warning based on the water content of the fuel product in the fuel line.
According to another embodiment of the present disclosure, a fuel delivery system is provided including a storage tank containing a fuel product, the fuel product having a water content, a fuel line having an inlet in communication with the storage tank, the fuel line being capable of receiving a first portion of the fuel product from the storage tank that is located at or above the inlet of the fuel line without receiving a second portion of the fuel product from the storage tank that is located beneath the inlet of the fuel line, at least one monitor operatively positioned along the fuel line, the at least one monitor collecting data indicative of the water content of the fuel product in the fuel line, and a controller in communication with the at least one monitor to receive collected data from the at least one monitor, the controller being programmed to automatically issue a warning based on the water content of the fuel product in the fuel line.
According to yet another embodiment of the present disclosure, a method is provided for monitoring a fuel delivery system including the steps of: directing a fuel product from a storage tank to a fuel dispenser via a fuel line; collecting data indicative of a water content of the fuel product in the fuel line; and automatically issuing a warning based on the collected data.
The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring initially to
According to an exemplary embodiment of the present disclosure, fuel 14 is a gasoline/ethanol blend. The concentration of ethanol in the gasoline/ethanol blend may vary from 0 vol. % to 10 vol. % or more. As such, fuel 14 may contain about 2.5 vol. % ethanol (“E-2.5”), about 5 vol. % ethanol (“E-5”), about 7.5 vol. % ethanol (“E-7.5”), about 10 vol. % ethanol (“E-10”), about 15 vol. % ethanol (“E-15”), or more, for example.
Storage tank 16 includes an internal, submersible pump 20, as shown in
As shown in
Storage tank 16 further includes drain valve 64 located at the bottom surface 17 of storage tank 16, as shown in
To operate fuel dispenser 12, the customer removes nozzle 28 from its cradled position of
Referring still to
An exemplary controller 40 is the TS-5 Fuel Management System available from Franklin Fueling Systems Inc. of Madison, Wis. However, it is within the scope of the present disclosure to use other controllers or microprocessors to perform the computing tasks described herein.
As shown in
An exemplary probe 50 is the TSP-LL2 Leak Detection and Inventory Control Probe available from Franklin Fueling Systems Inc. of Madison, Wis. However, it is within the scope of the present disclosure to use other probes to perform the monitoring tasks described herein.
The illustrative probe 50 of
Probe 50 may be configured to measure the temperature of the fluid in storage tank 16. In the illustrated embodiment of
Probe 50 may also be configured to measure the level of one or more fluids in storage tank 16. In the illustrated embodiment of
In addition to fuel 14, which forms an upper layer of fluid in storage tank 16, other fluids may be present in storage tank 16, such as lower fluid 80 and intermediate fluid 82. Lower fluid 80 may include substantially pure water and have a specific gravity of approximately 1.0. Intermediate fluid 82 may include a mixture of alcohol, water, and a small amount of gasoline (e.g., a mixture of 70 vol. % alcohol, 20 vol. % water, and 10 vol. % gasoline) resulting from phase separation, also referred to as a phase separated fluid. The specific gravity of intermediate fluid 82 is less than the specific gravity of lower fluid 80. For example, intermediate fluid 82 may have a specific gravity of approximately 0.80 to 0.89, and more particularly above 0.81. The upper fluid or fuel 14 may be a gasoline/ethanol blend, as discussed above. The specific gravity of the upper fluid or fuel 14 is less than the specific gravity of intermediate fluid 82. For example, the upper fluid or fuel 14 may have a specific gravity of approximately 0.68 to 0.78, and more particularly 0.73 to 0.75.
Each float 70, 72, 74, is configured to settle atop a corresponding fluid in storage tank 16. Lower float 70 may have a relatively high density (e.g., a density corresponding to a specific gravity of approximately 0.95) to sink through the upper fluid or fuel 14 and intermediate fluid 82 and settle atop lower fluid 80. As shown in
Additional information regarding the use of probe 50 to measure the level of one or more fluids in storage tank 16 is set forth in U.S. patent application Ser. No. 12/580,493, filed Oct. 16, 2009, entitled “Method and Apparatus for Detection of Phase Separation in Storage Tanks,” the entire disclosure of which is expressly incorporated herein by reference.
As shown in
In certain embodiments, the water content may be measured and communicated as a volume percentage of the total fluid flowing through fuel line 24 and/or in parts per million (ppm) on a volume (v/v) basis. For example, the first monitor 90 may measure and communicate a water content of 0.1 vol. % (where the remaining 99.9 vol. % constitutes fluid other than water) and/or a water content of 1000 ppm (v/v) (where the remaining 999,000 volume parts constitute fluid other than water). It is also within the scope of the present disclosure that the water content may be measured and communicated as a weight percentage of the total fluid flowing through fuel line 24 and/or in parts per million (ppm) on a weight (w/w) basis.
Monitors 90, 92, 94, may be positioned in any suitable location along fuel line 24 to analyze the fluid that is flowing from storage tank 16 via inlet 23 of pump 20 and to fuel dispenser 12. Although it is within the scope of the present disclosure that monitors 90, 92, 94, may be associated with fuel dispenser 12 (e.g., hose 26 of fuel dispenser 12), locating monitors 90, 92, 94, along a common fuel line 24 eliminates the need to provide monitors at each individual fuel dispenser 12. Also, although three in-line monitors 90, 92, 94, are illustrated and discussed herein, it is within the scope of the present disclosure that only one or two of these monitors may be provided. The illustrative monitors 90, 92, 94, send electric signals to controller 40 via corresponding wires 91, 93, 95, but it is also within the scope of the present disclosure that monitors 90, 92, 94, may communicate wirelessly with controller 40. In use, each monitor 90, 92, 94, may draw a sample from fuel line 24 and process that sample as necessary for testing.
The first monitor 90 of
The second monitor 92 of
In one embodiment, the turbidity monitor may measure attenuation (i.e., reduction in strength) of the source beam along its initial path as it passes through the fluid in fuel line 24. When the source beam is directed through a fluid with a relatively low water content and a relatively small number of particles, the beam will generally follow its initial path, so attenuation along the initial path will be relatively low. Stated differently, detection of the beam that remains along the initial path will be relatively high. By contrast, when the source beam is directed through a fluid with a relatively high water content and a relatively large number of particles, the beam will generally deviate from its initial path, so attenuation along the initial path will be relatively high. Stated differently, detection of the beam that remains along the initial path will be relatively low.
In another embodiment, the turbidity monitor may measure deflection of the source beam along a side path transverse to the initial path. When the source beam is directed through a fluid with a relatively low water content and a relatively small number of particles, the beam will generally follow its initial path, so detection of the beam along the side path will be relatively low. By contrast, when the source beam is directed through a fluid with a relatively high water content and a relatively large number of particles, the beam will generally deviate from its initial path, so detection of the beam along the side path will be relatively high.
Exemplary turbidity monitors are available from VWR International, LLC of Radnor, Pa., such as the Model 66120-200 Turbidity Meter. Such turbidity monitors may utilize a nephelometer having a light beam as the source beam and a light detector offset by about 90 degrees from the source beam. The nephelometer may output turbidity in units known as Nephelometric Turbidity Units (NTU).
To ensure that particles remain suspended in the fluid for detection by the turbidity monitor, the fluid should be in a dynamic and/or turbulent state during turbidity monitoring. If the fluid becomes too static before turbidity monitoring, the particles may settle in the fluid and avoid detection by the turbidity monitor. A turbidity monitor that operates continuously or substantially continuously may be capable of receiving and monitoring a dynamic fluid without allowing the fluid to become static between measurements.
The third monitor 94 of
In addition to monitors 90, 92, 94, a fourth monitor 96 may be provided to collect data from the fluid in drain line 66 and to communicate the collected data to controller 40. The illustrative fourth monitor 96 sends electric signals to controller 40 via a corresponding wire 97, but it is also within the scope of the present disclosure that the fourth monitor 96 may communicate wirelessly with controller 40. In use, the fourth monitor 96 may draw a sample from drain line 66 and process that sample as necessary for testing.
The fourth monitor 96 may be a capacitance monitor, like the first monitor 90, that is configured to measure the capacitance of the fluid in drain line 66. The fourth monitor 96 may also be capable of using the capacitance data to directly calculate and communicate the water content of the fluid in drain line 66 to controller 40, as discussed above. An exemplary capacitance monitor is the EASZ-1 system available from EESiFlo of Mechanicsburg, Pa. However, it is within the scope of the present disclosure to use other water-in-fuel monitors to measure the water content of the fluid in drain line 66.
In operation, controller 40 may receive continuous data feedback from probe 50 in storage tank 16, from one or more monitors 90, 92, 94, in fuel line 24, and/or from monitor 96 in drain line 66. Specifically, controller may receive continuous temperature data from temperature sensors 60a, 60b, 60c, 60d, 60e, in storage tank 16, continuous fluid height or volume data from floats 70, 72, 74, in storage tank 16, continuous water content data from monitors 90, 92, 94, 96 (e.g., continuous capacitance data from the first monitor 90 in fuel line 24, continuous turbidity data from the second monitor 92 in fuel line 24, continuous particle size data from the third monitor 94 in fuel line 24, and/or continuous capacitance data from the fourth monitor 96 in drain line 66). Microprocessor 42 of controller 40 runs the necessary software routines to collect, sort, and/or analyze this data.
According to an exemplary embodiment of the present disclosure, controller 40 signals an alarm or sends another suitable communication before phase separation occurs and before a phase separated fluid (e.g., intermediate fluid 82 of
Then, in step 204 of routine 200, controller 40 determines a maximum acceptable water content at the measured temperature. Above the maximum acceptable water content, the water content may be sufficient to cause phase separation. At or below the maximum acceptable water content, phase separation may be avoided. Because the solubility of water in a gasoline/ethanol blend varies based on the contents of the gasoline/ethanol blend (e.g., the concentration of ethanol in the blend, the presence of additives or blending agents in the blend, etc.) and temperature, the maximum acceptable water content may vary depending on the known or expected contents of storage tank 16 and the temperature in storage tank 16 (
In one embodiment, controller 40 accesses a reference chart or table, such as charts 300, 300′, 300″, of
Next, in step 206 of routine 200, controller 40 calculates the difference between the measured water content of the fluid and the maximum acceptable water content at the measured temperature. For example, with reference to chart 300 of
Then, in step 208 of routine 200, controller 40 evaluates the calculated difference DC and responds accordingly. If the calculated difference DC is relatively large, such that the measured water content 306 is safely beneath the maximum acceptable water content 302, as shown in
The size of the water content warning range DW should be selected to provide an adequate, advanced warning to the gas station operator that phase separation is approaching. In the illustrated embodiment of
In certain embodiments, controller 40 is programmed to progressively vary the alarm or warning communication across the water content warning range DW. For example, in the illustrated embodiment of
The size of each warning range DW1, DW2, DW3, should be selected to provide adequate, advanced warnings to the gas station operator that phase separation is approaching. In the illustrated embodiment of
The alarm or warning communication from controller 40 in step 210 allows the gas station operator to take precautionary measures to avoid phase separation in storage tank 16 (
One precautionary measure involves increasing the ethanol content in storage tank 16 to increase the maximum acceptable water content of fuel 14, such as by adding an ethanol-rich fuel to storage tank 16. If storage tank 16 currently contains E-2.5 fuel, the gas station operator may add ethanol-rich, E-10 fuel to storage tank 16 to arrive at E-5 fuel, for example. Rather than having to operate under the low maximum acceptable water content 302″ of
Another precautionary measure involves decreasing the water content in storage tank 16, such as by draining some or all of the water-rich fuel 14 from drain line 66 of storage tank 16 and adding fresh, water-deficient fuel 14 to storage tank 16. Under the same logic, the alarm or warning communication from controller 40 may warn the gas station operator against increasing the water content in storage tank 16, such as by adding a water-rich fuel to storage tank 16.
Yet another precautionary measure could involve increasing the temperature of storage tank 16, such as by pumping a warm heat exchange fluid around storage tank 16. Under the same logic, the alarm or warning communication from controller 40 may warn the gas station operator against decreasing the temperature of storage tank 16, such as by adding a new supply of low-temperature fuel to storage tank 16.
In addition to receiving water content data (e.g., capacitance data) from the first monitor 90 (
Next, in step 404 of routine 400, controller 40 calculates the difference between the current temperature measurement and a prior temperature measurement, the prior temperature measurement being measured a predetermined time (e.g., 5, 10, or 15 seconds) before the current temperature measurement. With reference to chart 300 of
Then, in step 406 of routine 400, controller 40 evaluates the calculated temperature change TC and responds accordingly. If the calculated temperature change TC over the predetermined time (i.e., the rate of temperature change) is relatively small, controller 40 takes no responsive action and returns to step 402 to continue monitoring temperature data. On the other hand, if the calculated temperature change TC over the predetermined time (i.e., the rate of temperature change) is relatively large and exceeds an acceptable temperature change TA, controller 40 may activate an alarm or send another suitable warning communication in step 408. The alarm of step 408 may be activated independently of the alarm of step 210 (
The size of the acceptable temperature change TA should be selected to provide an adequate, advanced warning to the gas station operator that the temperature in storage tank 16 is dropping. It is also within the scope of the present disclosure that the size of the acceptable temperature change TA may vary. For example, the size of the acceptable temperature change TA may decrease (i.e., become more sensitive) as the measured temperature 304 decreases to provide more advanced warning to the gas station operator that the temperature in storage tank 16 is dropping.
The alarm or warning communication from controller 40 in step 408 allows the gas station operator to take precautionary measures to avoid phase separation in storage tank 16 (
Next, in step 504 of routine 500, controller 40 calculates the difference between the current water content measurement and a prior water content measurement, the prior water content measurement being measured a predetermined time (e.g., 5, 10, or 15 seconds) before the current water content measurement. With reference to chart 300 of
Then, in step 506 of routine 500, controller 40 evaluates the calculated water content change WC and responds accordingly. If the calculated water content change WC over the predetermined time (i.e., the rate of water content change) is relatively small, controller 40 takes no responsive action and returns to step 502 to continue monitoring water content data. On the other hand, if the calculated water content change WC over the predetermined time (i.e., the rate of water content change) is relatively large and exceeds an acceptable water content change WA, controller 40 may activate an alarm or send another suitable warning communication in step 508. The alarm of step 508 may be activated independently of the alarm of step 210 (
The size of the acceptable water content change WA should be selected to provide an adequate, advanced warning to the gas station operator that the water content in storage tank 16 is increasing. It is also within the scope of the present disclosure that the size of the acceptable water content change WA may vary. For example, the size of the acceptable water content change WA may decrease (i.e., become more sensitive) as the measured water content 306 increases to provide more advanced warning to the gas station operator that the water content in storage tank 16 is increasing.
The alarm or warning communication from controller 40 in step 508 allows the gas station operator to take precautionary measures to avoid phase separation in storage tank 16 (
The third software routine 500 may be adapted to receive measured water content data (e.g., turbidity data) from second monitor 92, as shown in the modified routine 500′ of
Next, in step 504′ of routine 500′, controller 40 calculates the difference between the current turbidity measurement and a prior turbidity measurement, the prior turbidity measurement being measured a predetermined time (e.g., 5, 10, or 15 seconds) before the current turbidity measurement. Controller 40 may retrieve the prior turbidity measurement from memory 44 (
Then, in step 506′ of routine 500′, controller 40 evaluates the calculated turbidity change and responds accordingly. In this manner, trends in the turbidity data may be evaluated without necessarily having to identify and reference a predetermined, maximum acceptable turbidity level. If the calculated turbidity change over the predetermined time (i.e., the rate of turbidity change) is relatively small, controller 40 takes no responsive action and returns to step 502′ to continue monitoring turbidity data. On the other hand, if the calculated turbidity change over the predetermined time (i.e., the rate of turbidity change) is relatively large and exceeds an acceptable turbidity change, controller 40 may activate an alarm or send another suitable warning communication in step 508′, as discussed further above.
The size of the acceptable turbidity change should be selected to provide an adequate, advanced warning to the gas station operator that the water content in storage tank 16 is increasing. In the experimental example that follows (Table 1 and
An acceptable turbidity change may also be expressed as a percentage of a prior turbidity measurement (e.g., an initial turbidity measurement). According to an exemplary embodiment of the present disclosure, an acceptable turbidity change over a predetermined time may be about 15%, 20%, 25%, or 30% of the prior turbidity measurement if more sensitivity is desired, or about 35%, 40%, 45%, 50%, or more of the prior turbidity measurement if less sensitivity is desired. If a fuel product has an initial turbidity measurement of about 1.10 NTU, for example, a turbidity measurement that exceeds 1.27 NTU (which represents a 15% increase) or 1.65 NTU (which represents a 50% increase) may cause controller 40 to activate the alarm. It is also within the scope of the present disclosure to progressively vary the alarm as the turbidity measurements increase, as discussed above.
In another embodiment, step 506′ of routine 500′ involves evaluating a time-ordered series of turbidity measurements, such as the most recent 3, 5, 7, or more turbidity measurements. If each turbidity measurement in the series increases, controller 40 may activate the alarm. However, if one or more of the turbidity measurements in the series decreases, controller 40 may assume that turbidity is relatively constant and may return to step 502′ to continue monitoring water content data (e.g., turbidity data).
According to another exemplary embodiment of the present disclosure, controller 40 signals an alarm or sends another suitable communication after phase separation occurs. In the illustrated embodiment of
Additional information regarding the use of probe 50 to detect phase separation in storage tank 16 is set forth in the above-incorporated U.S. patent application Ser. No. 12/580,493, filed Oct. 16, 2009, entitled “Method and Apparatus for Detection of Phase Separation in Storage Tanks”
The alarms or warning communications from controller 40 in step 610 (
Turbidity testing was performed on three fuel products. The first fuel product was a CE25a reference blend, which includes 75 volume % ASTM Fuel C and 25 volume % ethanol, as set forth in SAE J1681. The second fuel product was an E-10 blend, referred to herein as E-10(a), sampled from a fueling station. The third fuel product was another E-10 blend, referred to herein as E-10(b), sampled from a different fueling station.
Samples were prepared by adding a desired amount of water to each fuel product, as set forth in Table 1 below. Each sample was disturbed by turning the sample tube back and forth to minimize static settling of any particles contained therein. Then, each disturbed sample was immediately evaluated using the above-described Model 66120-200 Turbidity Meter. Turbidity results are presented in Table 1 below and are also presented graphically in
The volume of water added to each fuel product was increased until visible phase separation occurred. With reference to Table 1 above, visible phase separation occurred in the first fuel product (CE25a) after 0.848 volume % of water had been added, in the second fuel product (E-10(a)) after 0.274 volume % of water had been added, and in the third fuel product (E-10(b)) after 0.556 volume % of water had been added. The initial water content, if any, of the second and third fuel products was unknown. The third fuel product may have contained less water than the second fuel product before testing, which would explain why the third fuel product was able to take on more water than the second fuel product during testing.
While this invention has been described as having exemplary designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
This application claims priority from U.S. Provisional Patent Application Ser. No. 61/545,655, filed Oct. 11, 2011, and from U.S. Provisional Patent Application Ser. No. 61/476,068, filed Apr. 15, 2011, the disclosures of which are hereby expressly incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61545655 | Oct 2011 | US | |
| 61476068 | Apr 2011 | US |
