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Pumping Systems and Day Tanks

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1 Pumping Systems and Day Tanks
Presented By Ken Still, CB Kramer

2 Agenda Introduction Basic System Generator Pump Selection
Boiler Pump Selection Pump Types and Limits Day Tanks Day Tank Accessories Pump and Day Tank Control Conclusion We are going to cover a lot of ground, briefly discussing the basic diesel fuel system and each of the usual components. There is no way to get into great detail in the amount of time we have today but feel free to stop me for any questions and I will do my best to answer them. Here is what we are covering…. Basic System Diagram Mechanical Components Storage Tanks Fill Options Piping and Valves Pump Sets Day Tanks Fuel Oil Maintenance Control and Communication

3 Introduction Ken Still – CB Kramer
Pump sets and day tanks typically operate as a single system with a common controller. Personal bio and then explain that the pumps and day tanks operate as a single system. The pumps are normally ran off of day tank or system demand.

4 Basic System Monitoring and Control
A typical fuel systems is going to have 2 or more storage tanks providing diesel fuel to 2 or more generators, though specific systems will require slightly different arrangements and specialty devices. The generators will have day tanks, either stand alone or belly tanks. Day tanks are optional for boilers, used to solve particular installation issues. In any case, on multiple tank applications , provisions must be made to ensure proper control in filling the day tanks. The components we provide are: Monitoring and control systems Day tanks and accessories Fuel Maintenance systems Pump Sets, duplex and custom We can provide most of the other pieces of a system but add little value to those components.

5 Generator Pump Selection
7 gph per 100KW = GPH GPH x # gensets = GPH Total GPH total x 4 = transfer pump size Pump sizing is typically straightforward. Calculate the total generator load, convert KWH to GPH fuel consumption then multiply by 4 to determine pump size. The factor of 4 is typical with the goal to provide a 15 minute fill cycle at full load for the pumps. This factor can be altered, especially in multi day tank applications as long as the designer is accounting for all of the variables. The following table was developed to assist in sizing the transfer pumps for a generator fuel system. This table is not designed to replace proper engineering calculations in final system design. The fuel consumption is based on the rule of thumb that it takes about 7 gallons of #2 diesel fuel per hour to generate 100KW electrical power in a single generator.


7 Boiler Pump Selection Typical boiler system selection
30gph per 100 BHP = GPH GPH x # boilers = GPH total GPH total x 2.5 – 3 to accommodate boiler mounted pump total flow Typical modern boilers will fire natural gas as the primary fuel, with a percentage of these using #2 fuel oil as a backup fuel. A system designer should be aware of a couple of key points when involved with boiler fuel oil systems. 1) Most boilers firing fuel oil will have their own fuel oil pump. 2) This pump can typically handle a low suction pressure of 15”Hg without difficulty but a high suction pressure of over 3psi can cause the failure of the pumps seals. This high pressure can be caused by a fuel transfer pump or the static head caused by an elevated (relative to boiler pump) supply system.


9 Typical System w Boiler Pumps
Boiler Mounted pump limitations Tight pump suction limits; 15”hg – 3psi Boiler pump single point of failure Boiler pumps requires times flow rate (sometimes 10-15x more) from transfer pump Simplifying the fuel system , reducing capital and operational costs is simple, the fuel systems for modern boilers have evolved in a way that more than 80% of new boilers that burn fuel oil are provided with their own on-board fuel oil pumps. If the onboard pumps have the ability to pump directly from the single storage tank this may be a very practical and efficient arrangement. In most systems this is not typical and a transfer pump is needed to pump oil out of the storage tank(s) and deliver to the boiler mounted pumps at a very low pressure. This transfer pump must be over sized by a factor of to accommodate the extra flow required by the onboard pumps. Always check the flow of the fuel pump supplied by the manufacturer. On some boilers there can be a 5 to 10 times factor for the pump size compared with the burn rate. A simple solution is to do away with the boiler’s onboard pumps and increase the supply pressure from the transfer pumps.

10 Typical System w Boiler Pumps
The system unnecessarily complex with a single point of failure at boiler mounted pump.

11 Alternative Boiler System
This arrangement will eliminate the cost and electrical load of the boiler mounted pumps, reduce the electrical load of the transfer pump as well as reduce the required pipe sizing. The only cost adder may be a pressure regulator on the fuel supply pipe to each boiler. This cost is usually offset by the elimination of the burner pump and removes the single point of failure that the burner mounted pump introduces. This table was developed to assist in sizing the transfer pumps for a boiler fuel oil system. This table is not designed to replace proper engineering calculations in final system design. The fuel consumption is based on a typical firetube boiler firing 140,000btu/g #2 fuel oil.

12 PRESSURE (submersible) PUMPS
Pump Types SUCTION PUMP SET PRESSURE (submersible) PUMPS Choosing between a submersible pump and a suction type pump set is fairly easy. A suction type pump set is almost always the best choice when accounting for ease of operation and maintenance. The primary point when considering locating a suction pump set is the location relative to the vertical distance between the bottom of the storage tank to the actual pump suction. If this lift (plus the pressure drop through piping, valves and fittings) exceeds the 15”Hg capacity of a suction pump then the design engineer has no other option than to specify a submersible pump. Other key points of consideration in the installation of a suction pump are the availability of space and facility lay-out. Match the pump to the application Suction or pressure type

13 Pump Sets Submersible Pumps Pro Con Submerged suction
Simple single tank systems Simple installation Con Pressurized in-ground piping Limited sizes Difficult maintenance Unmanned spaces Piping Monitoring Complicated multi-tank redundant systems These pumps were designed for the service station industry and then applied to industrial systems. The primary mfr of these types are FE Petrol (Franklin Fueling) and Red Jacket. Most pumping problems are suction problems, a submersible pump doesn’t have such issues. If the system is going to have any underground piping note that the EPA has requirements for leak testing of buried piping. Pressurized piping systems have a much more stringent requirement for testing than suction type systems. In fact, if the suction type system piping; 1) is installed with enough slope back to the storage tank to complete drainage after the pump shuts off, and 2) the only check valve installed is installed close to the pump, then no leak detection system is required for the piping. All other systems are required to employ monitoring systems and line tightness testing on a periodic basis.

14 Pressure Pump System Redundancy Each tank must have redundant pumps
Pressure Pumps are completely submerged in the fuel with the pump inlet at a minimum of 6” from the bottom of the tank. Full redundancy requires the use of 2 pumps in each tank. Typically, each pump will require a separate piping sump when the tanks are buried. This is to allow clearance to install and remove the pump.

15 Pump Sets Suction Pumps Pro Con Buried piping under suction
Ease of maintenance Simpler multi tank systems Simple installation Con Limited suction ability Additional floor space Operators preference is typically to have a suction type pump sets that are easy to maintain and provide full redundancy.

16 Suction Pump System Redundancy
A single duplex pump set satisfies redundancy requirement Suction Type Pump sets may be constructed using multiple pump arrangements. The typical pump set is a duplex type which should be specified to mean two pumps, each sized to meet the entire system flow requirements with the other being fully redundant.

17 Suction Pump Set Options
High Pressure 100psi Low Pressure <50 psi Critical Fuel Systems manufactures complete pump sets for Mission Critical applications. Our standard duplex pump sets range from 36gph to 3,000gph. Custom pump sets can be designed to meet most any application or configuration. Our positive displacement pump sets are built for reliable, safe operation and engineered to protect the environment. mechanical pump set pump set with motor starter panel Pump set with motor starter and logic control panels

18 Suction Pump Set Contruction
Control panel(s) Relief valves Flow switch Priming funnel Suction strainer(s) Gauges Pump/motor sets Reservoir base w/leak switch

19 Basic System Monitoring and Control Day Tanks

20 Day Tanks Built and certified to UL142 Pressure tested to 5 psi
Almost always used on generators Stand Alone Belly Tank Sometimes used on boilers

21 Day Tanks Stand Alone Generator Belly Tank
The belly tank and any instrumentation installed within are going to be subjected to significant vibration. Reed switches used in multi-point float switches are particular susceptible.

22 Belly Tanks Completely isolate tank from generator Flexible fuel hose
The generator and engine will sit right on top of the belly tank. Because of the tremendous amount of vibration created by the engine care must be taken to ensure that belly tank is isolated, as much as possible from the genset. This is done by placing springs between the genset and the base tank and using flexible hose connections to feed fuel to the engine. Even with this isolation the belly tank may still be subjected significant vibrations. The belly tank is built as a structural component to not only withstand the vibration but also the entire weight of the engine generator. The instrumentation installed in the base tank should be hardened against high vibration and inspected regularly for proper operation and structural integrity. The generator belly tanks must meet the same requirements as independent day tanks, be UL 142 listed and provide containment. Spring isolation

23 Independent Day Tanks Double Wall Return Pump Option
Diesel fuel systems are being built larger every year. The larger the systems, the larger the piping runs, the more fuel that they hold. This added volume often can’t be contained by an open top rupture basin should the day tank vessel fail. A totally enclosed double wall day tank offers the best chance of containment providing a positive, sealed, and pressure tested barrier between the diesel fuel and the environment.

24 Independent Day Tanks Single Wall Single Wall w/Tub Type Rupture Basin
Available w/o rupture basin Even though the double wall tank is our standard we still offer the single wall systems with or without rupture basins. Critical Fuel Systems also provides a complete line of day tank trim accessories, from level controls to fill manifolds, to meet specific project needs.

25 Day Tank Accessories Automatic fill manifold Multi-tank applications
Sized to precisely match required flow Point out individual components

26 Day Tank Accessories Return Pumps
Manipulate tank level to test controls Refresh fuel if it overheats Empty day tank in emergency Return pumps serves a few different purposes, the first is to provide a means to lower the level of the day tank during start-up and periodic testing. The second reason one would install a day tank with return pumps would be to provide for refresh fuel with relatively cool fuel from the storage tank. The third and final primary purpose of including a return pump is to empty the day tank in the emergency. The return pump should be sized to empty the day tank faster than the tank will fill under normal operation.

27 Day Tank Accessories Accessories Vent Caps Level Indication
Level Monitoring Others

28 Day Tank Sizing No rules or regulations requiring minimum sizes.
Some regulations limiting maximum sizes IFC limit to 660 gallons in certain installations Generator KW x .07 x hours desired = tank size Often space dependent

29 Day Tank Construction Fittings in top of tank (except drain)
Easy access to all fittings Drop tubes on all supply and returns Keep the inflow away from generator suction

30 Pump and Day Tank Controls
Primary functions Monitor day tank level Start/stop pumps Open/close fill manifolds Secondary functions Leak detection Communications and alarms Auxiliary controls

31 Pump and Day Tank Controls
Low voltage logic control not to exceed 49 volts Safe Design High voltage separate from low voltage Easy serviceability and compliance to NFPA and OSHAE standards High voltage motor control panel Industrial equipment controls should be designed with the knowledge that the panel is going to be opened for various evolutions, some of which require that panel to be live at the time. Start up technicians and maintenance personnel often have to access the panel while it’s energized to check various circuits, limits and switches for proper voltage and continuity. This can be done safely and legally if the design is correct. Most systems are going to be comprised of high and low voltages. The solution is to specify that the controller and all associated circuits be low voltage, not to exceed 49 volts, and built into their own UL508 listed industrial control panel. The high voltage motor starters, transformers and disconnects be contained in a separate UL508 listed industrial control panel.

32 Pump and Day Tank Controls
NFPA 70e This standard is not intended to regulate the design of equipment but to provide workplace standards to increase safety for those that work around and/or with electrical equipment. By paying attention to standards such as these equipment manufacturers have the opportunity to design products that are safer to operate and maintain, reducing the administrative costs and efforts for the end users.

33 Conclusion Basic System Generator Pump Selection Boiler Pump Selection
Pump Types and Limits Day Tanks Day Tank Accessories Pump and Day Tank Control We covered this material quickly if you have any questions you may refer to the design guide or get in touch with me.

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