Power (Combustion)
Fuel Unloading / Forwarding / Transfer
There are a wide range of fuels that a plant can burn and they arrive into a power plant through various means – rail car‚ ship‚ tank truck‚ etc.. Unloading pumps feed directly into a storage tank often times without a control valve/system and are found on the ‘vehicle’ or may be part of the tank storage system.
Our experience shows that when fuel is allowed to sit in a rail car‚ tank truck‚ etc. the viscosity of the fluid can increase. This change results increased input torque requirements and potentially the delivered. In positive displacement pumps‚ the delivered flow will increase and in centrifugal pumps the amount will decrease. It is important when sizing your pump to consider the properties of the fluid‚ pressure‚ supply and operational objectives.
Some storage systems use a “day tank” that holds about a day’s worth of “treated” (Filtered‚ additives added‚ and/or blended) fuel near the power plant leaving the larger volume storage somewhat more remote from the generating facility. Transfer pumps are needed to keep the day tank supplied as well to move oil from one tank to another. Also‚ transfer or forwarding pumps will be needed to send fuel oil to the inlet of the fuel injection pumps from either the day tank or the main storage tanks.
The distance that the fuel has to travel is an important consideration. Be sure to calculate the frictional loss in your pipeline so you know the maximum discharge pressure and the size of the driver required to overcome the pressure differential.
Commonly used pumps in this application include three screw‚ two screw and centrifugal.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump type |
|---|---|---|---|
|
91 m^3/h 400 GPM |
34.5 bar 500 psi |
121C 250F |
IMO 3D Three Screw |
|
272 m^3/h 1‚200 GPM |
70 bar 1‚015 psi |
82C 180F |
IMO 8L Three Screw |
|
317 m^3/h 1‚400 GPM |
100 bar 1‚450 psi |
250C 482F |
Allweiler SN Three Screw |
|
480 m^3/h 2‚120 GPM |
16 bar 232 psi |
140C 284F |
Allweiler NB Centrifugal |
|
750 m^3/h 3‚300 GPM |
21 bar 300 psi |
260C 500 F |
IMO 323F Three Screw |
|
792 m^3/h 3‚500 GPM |
97 bar 1‚400 psi |
121C 250F |
Warren FSXA Two Screw |
|
1‚100 m^3/h 4‚844 GPM |
16 bar 232 psi |
100C 212F |
Houttuin 216.40 Horizontal Two Screw |
|
1‚100 m^3/h 4‚844 GPM |
16 bar 232 psi |
100C 212F |
Houttuin 211.40 Vertical Two Screw |
|
2‚300 m^3/h 10‚158 GPM |
16 bar 232 psi |
140C 284F |
Allweiler NT Centrifugal |
|
2‚500 m^3/h 11‚008 GPM |
16 bar 232 psi |
140C 212F |
Houttuin 236.40 Horizontal Two Screw |
Combustion Overview
HOW A COMBUSTION POWER PLANT OPERATES:
The Combustion Turbine is similar to a large jet engine which has its hot exhaust directed to a power turbine. Natural gas is ignited and burned. The turbine converts the linear thrust into rotational energy which then drives a generator. Since there is no steam component to the power plant and thus no condenser cooling water necessary‚ gas turbine plants can be sited nearly anywhere. Turnkey installations can be up and running in as little as a few months.
The primary fuel is natural gas‚ however‚ in some instances these power plants have back up systems supported by liquid fuel or diesel (distillate) oil although residual oils and occasionally crude oil have also been used to initiate the combustion reaction.
When liquid fuel is something other than distillate‚ a fuel treatment system is usually provided by the gas turbine OEM to remove undesirable components in the fuel which would otherwise cause excessive corrosion in the gas turbine system. Such systems have main- and standby-fuel transfer pumps. The burner or fuel injection pumps are usually high pressure pumps (to 1800 psi). The gas turbine may be started and stopped using clean distillate fuel oil while using a heavy residual fuel for normal running. This puts a demand on the injection pump to handle a wide fuel viscosity and temperature range.
NAPTHA has been used as a liquid fuel when available as a surplus refinery byproduct. CIRCOR brands Warren and Tushaco two screw pumps are successfully used in power plants burning NAPTHA.
CIRCOR CAPABILITIES
CIRCOR brands Allweiler‚ IMO‚ IMO AB‚ Warren and Tushaco supply product into natural gas power plants. Global combustion plants have turned to CIRCOR brands to provide a wide variety of pumping solutions with technologies that include three screw pumps‚ two screw pumps‚ crescent internal gear pumps‚ progressing cavity pumps‚ centrifugal pumps‚ as well as lubrication solutions that include the PurLube and the Oil Mist.
| Pump Applications | Engineered System Applications | Oil Service |
|---|---|---|
|
Fuel Unloading/Forwarding/Transfer |
Unloading/Forwarding/Transfer |
PurLube |
|
Fuel Unloading/Transfer/Forwarding |
Fuel Unloading/Transfer/Forwarding |
PurLube |
|
Rotor Jacking |
Fuel Injection |
Oil Mist |
|
Lubrication |
Lubrication & Rotor Jacking |
|
|
Fuel or Burner Injection |
Water injection for NOx reduction |
|
|
Chemical Metering |
Purge Water systems |
|
|
Hydrogen Cooled Generator Seal Oil |
|
|
Chemical Metering
There are multiple chemical metering applications within power plants. In all applications high quality materials and requirements on sealing are high. CIRCOR is able to support your application with materials and sealing options that meet your environmental requirements. Two sample applications include –
Organometallic Magnesium Injection:
In combustion plants that use a heavy fuel or ash forming oils for combustion such as blends‚ crude and residual oils‚ a vanadium corrosion inhibitor like organometallic magnesium (Mag-Oxide) is injected into the fuel which prevents the high temperature corrosion in gas turbines caused by vanadium. Crude oils and heavy residual fuels usually contain organic vanadium which is extremely corrosive to the hot gas path of the turbine. Vanadium is not present in liquid fuels in a water soluble form and cannot be removed through the washing process.
Three Mag-Oxide additives are commonly employed in this process‚ magnesium sulfonate‚ magnesium oxide and magnesium sulfate. The final decision is largely dependent on the economics of the system and the amount of vanadium present in the fuel.
CIRCOR brand Zenith metering pumps are the choice for this application.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump type |
|---|---|---|---|
|
31 m^3/h 7 GPM |
69 bar 1000 psi |
343C 645F |
Zenith B-9000 Metering Gear |
|
8.3 GPH |
98 bar 1500 psi |
148C 300F |
Zenith B Series Metering Gear |
Water Treatment
In steam plant and combined cycle plants‚ boiler feed water is treated to ensure that the ph is neutral. This minimizes the effects on the steam turbine. Chemical treatments are site specific and can be either with a base or acid solution. Chemical metering applications also include pumping algaecides and corrosion control chemicals into condenser cooling water.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump type |
|---|---|---|---|
|
240 m^3/h 1057 GPM |
25 bar 362 psi |
160C 320F |
Allweiler ALLCHEM Centrifugal |
|
105 m^3/h 462 GPM |
25 bar 362 psi |
250C 482F |
Allweiler ALLMAG Centrifugal |
Hydrogen cooled generator seal oil
Very large generators have their casing filled with hydrogen to reduce windage losses from the huge rotating generator rotor. In order to contain the extremely volatile hydrogen in the casing‚ pumps are used to pump oil into the generator shaft labyrinth seals at a pressure higher than the hydrogen. This keeps the generator seals pressurized containing the hydrogen.
The oil gravity drains to a tank located about 2 meters above the oil pumps. As a result‚ the oil pump inlet pressure is extremely low. Three screw pumps are used for their high reliability and ability to operate at extremely low suction pressures as well as their ability to operate at higher speeds than comparable flow gear pumps. Other systems integrate the seal oil system into the lube oil tank and use centrifugal pump.
Each hydrogen cooled generator is served by a main and auxiliary seal oil pump driven by an AC motor. There is also an emergency DC motor driven pump to provide the critical oil in the event of a turbine trip where AC power is not available. This allows the generator to safely coast down with out leaking the hydrogen gas.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump type |
|---|---|---|---|
|
51 m^3/h 225 GPM |
16 bar 232 psi |
155C 311F |
IMO AB ACG Three Screw |
|
51 m^3 / h 225 GPM |
16 bar 232 psi |
120C 250F |
Allweiler ALLlub RUV Three Screw |
|
91 m^3/h 400 GPM |
34.5 bar 500 psi |
120C 250F |
IMO 3D Three Screw |
|
180 m^3/h 793 GPM |
16 bar 232 psi |
130C 266F |
IMO AB ACF Three Screw |
|
317 m^3/h 1‚400 GPM |
100 bar 1‚450 psi |
250C 482F |
Allweiler SN Three Screw |
|
550 m^3/h 2‚500 GPM |
16 bar 232 psi |
120C 250F |
Allweiler NSSV Centrifugal |
Rotor Jacking
Large frame-sized turbines found in utility scale steam‚ combustion and combined cycle power plants use high-pressure hydraulic oil pumps to lift the turbine shaft from its sleeve bearings before the turbine is started. Hot turbines that are being shut down are put on “turning gear” drive. This allows the turbine to rotate very slowly while it cools so its shaft does not sag due to its weight. A hydraulic oil motor drives a gear which maintains this slow rotation of the turbine shaft.
When evaluating a pump for this application‚ ensure that the pump and inlet piping are properly sized to handle cold start conditions because lower temperature affects the viscosity of the lubrication oil and Net Positive Inlet Pressure Available (NPIPA). The lift capability of a pump decreases with temperature.
Suitable pumps here are three screw and crescent internal gear pumps.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump type |
|---|---|---|---|
|
13 m^3/h 55 GPM |
210 bar 3,046 psi |
80C 176F |
Allweiler SD Three Screw |
|
28 m^3/h 125 GPM |
345 bar 5000 psi |
82C 180F |
IMO CIG Crescent Internal Gear |
|
91 m^3/h 400 GPM |
151 bar 2‚200 psi |
120C 250F |
IMO 12D Three Screw |
Lubrication
If it is large and rotates‚ it most certainly needs a pumped lubrication system. Pumps and engineered systems that supply lubrication oil to rotating equipment generally operate 24/7 making reliability of paramount importance.
On a typical lubrication oil skid‚ there are generally three pumps‚ a primary‚ a standby and an emergency backup pump. You may also find a seal oil pump included for the hydrogen cooled generators. These pumps and engineered system supply lubrication oil to the main journal bearings‚ generator bearings‚ reducing gear‚ accessory gear‚ high pressure hydraulic oil and generator seal oil.
The required flow rates depend on the size of the rotating equipment. In large steam and gas turbine applications flow rates as high as 2‚500GPM are required vs. stationary diesel applications where less than 500GPM required.
Users may have a choice between centrifugal and three screw pumps in these applications and there are trade offs between the technologies that engineers should be aware of. Centrifugal pumps typically have a lower initial cost; however‚ three screw pumps have a lower life cycle cost when you factor in operating efficiency and thus energy costs and maintenance costs.
CIRCOR also produces complete lubrication engineered systems for rotating equipment throughout the power plant. These applications include turbine‚ boiler feed‚ condensate‚ and recirculation pumps.
CIRCOR provides optimal pump technologies with three screw‚ two screw and centrifugal pumps.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand, Series & Pump types |
|---|---|---|---|
|
2.7 m^3/h 12 GPM |
7 bar 101 psi |
90C 194F |
IMO AB ACD Three Screw |
|
11 m^3/h 48 GPM |
16 bar 232 psi |
155C 311F |
IMO AB ACE Three Screw |
|
28 m^3/h 125 GPM |
345 bar 5‚000 psi |
82C 180F |
IMO CIG Crescent Internal Gear |
|
48 m^3/h 210 GPM |
17 bar 250 psi |
107C 225F |
IMO 3G Three Screw |
|
51 m^3/h 225 GPM |
16 bar 232 psi |
120C 250F |
Allweiler ALLlub RUV Three Screw |
|
51 m^3/h 225 GPM |
16 bar 232 psi |
180C 356F |
IMO AB ACG Three Screw |
|
91 m^3/h 400 GPM |
34.5 bar 500 psi |
121C 250F |
IMO 3D Three Screw |
|
180 m^3/h 793 GPM |
16 bar 232 psi |
121C 250 F |
IMO AB ACF Three Screw |
|
450 m^3/h 1‚982 GPM |
16 bar 232 psi |
90C 194F |
IMO AB LPQ Three Screw |
|
453 m^3/h 2‚000 GPM |
16 bar 232 psi |
150C 356F |
Allweiler TriLub Three Screw |
|
490 m^3/h 2‚158 GPM |
16 bar 232 psi |
80C 176F |
Houttuin 215.10 Vertical Submersible Two Screw |
|
550 m^3/h 2‚500 GPM |
16 bar 232 psi |
120C 250F |
Allweiler NSSV Centrifugal |
|
600 m^3/h 2‚642 GPM |
16 bar 232 psi |
80C 176F |
Houttuin 211.10 Horizontal Two Screw |
|
750 m^3/h 3‚300 GPM |
21 bar 300 psi |
260C 500F |
IMO 323F Three Screw |
|
1‚100 m^3/h 4‚844 GPM |
16 bar 232 psi |
80C 176F |
Houttuin 216.10 Horizontal Two Screw |
Fuel or Burner Injection
Fuel injection or burner pumps and the engineered systems that they are mounted on dispense fuel directly into the gas turbine or oil fired boiler. These pumps and engineered systems provide a mission critical operation for the power plant with the main pumps mounted in a three 50% capacity configuration: one as a hot standby; one for up to 50% load; and a third pump coming on for loads in the 50 to 100% range or two 100% capacity pumps (one running with one standby).
Pump applications require flow rates in the 50 to 400gpm range per pump for utility scale combustion‚ steam and combined cycle turbines with discharge pressures in the 700 to 1800 psi range. In specific applications‚ CIRCOR has worked with manufacturers to develop pump solutions that can handle discharge pressure of 2000 psi at a flow of 500GPM. Stationary diesel applications require lower flow rates and pressures.
Coal fired steam plants use Fuel or Burner injection pumps to pump oil into the burner to either keep the coal burning or speed the temperature rise in the boiler. In some applications where Bio-Mass fuel is incorporated the fuel or burner injection pumps will be operated in order to produce an even combustion temperature to compensate for varying BTU content in the Bio-Mass fuel. In combustion and combined cycle plants‚ liquid fuels (distillate‚ fuel oil #4‚ #6‚ etc.) are used as back up supply for the primary fuel natural gas.
Consistency of output and smooth pulsation free flow are primary criterion for purchase in fuel or burner injection pump applications making three screw‚ two screw or crescent internal gear pumps as the suitable choice. Often times‚ pumps are sized for 125 – 150% of the delivered flow requirements. Engineers design for future expansions and planned upgrades and design a bypass system to accommodate the excess flow delivered. Users should recognized that excess pumping costs money and running a bypass systems 24/7 can quickly eat up savings.
Finally‚ Allweiler brand ALLHEAT thermal oil centrifugal pumps are used in small decentralized biomass combined heat and power plants in an Organic Rankine Cycle (ORC) process. In this application‚ silicon oil is vaporized in a boiler and used in a steam turbine instead of water/steam. The heat cannot be transferred directly from the burner to the silicon oil as the heat is too high. Therefore‚ thermal oil is heated to around 150F/300C and this heat is then transferred to the silicon oil.
| Flow Rates up to | Pressures to up to | Max Fluid Temperature | CIRCOR Brand & Series |
|---|---|---|---|
|
28 m^3/h 125 GPM |
345 bar 5‚000 psi |
82F 180C |
IMO CIG Crescent Internal Gear |
|
78 m^3/h 343 GPM |
280 bar 4‚061 psi |
150C 302F |
Allweiler VH Three Screw |
|
91 m^3/h 400 GPM |
34.5 bar 500 psi |
120C 250F |
Imo 3D Three Screw |
|
91 m^3/h 400 GPM |
103 bar 1‚500 psi |
120C 250F |
IMO 6D Three Screw |
|
91 m^3 / h 400 GPM |
151 bar 2‚200 psi |
120C 250F |
IMO 12D Three Screw |
|
272 m^3/h 1‚200 GPM |
70 bar 1‚015 psi |
82C 180F |
IMO 8L Three Screw |
|
750 m^3/h 3‚300 GPM |
21 bar 300 psi |
260C 500F |
IMO 323F Three Screw |
|
792 m^3/h 3‚500 GPM |
97 bar 1‚400 psi |
121C 250F |
Warren FSXA Two Screw |
|
1‚450 m^3/h 6‚380 GPM |
25 bar 363 psi |
400C 752F |
ALLHEAT Centrifugal |
|
2‚500 m^3/h 11‚008 GPM |
80 bar 1‚160 psi |
400C 752F |
Houttuin Engineered Two Screw |