T-Power Plant Mumbo Jumbo

Hosgeldiniz	TEKNOLOJI POWER PLANT MUMBO JUMBO by Rob Abbott (26 Mart 2004)	Yonetim
Yorum		Elektrik Pazari
Haberler		Kaynaklar
Teknoloji		Ozgecmisim
Isletme ve Bakim		E-Mail

Bir konuyu basite indirgeyerek aciklayabilmek ancak konusunda uzmanlasmis ve ogretim kabiliyetine sahip kisilere mahsustur. Kanada'da calistigim firmada Mr. Rob Abbott isimli arkadasim boyle uzmanlardan biri. Mr. Abbott, firmamizdaki avukat ve finansmanci gibi teknik olmayan elemanlara kombine cevrim ve kojenerasyon teknolojilerinin temel kavramlarini aciklayabilmek icin 26 Mart 2004'de bir seminer verdi. Mr. Abbott'un izni ile, seminerde kullanilan slaylari (formatini kismen degistirerek) assagida veriyorum. Faydalanacaginizi umarim. Bu slaylar Mr. Abbott'un izni olmadan kopyalanip basilamaz veya baska bir web sayfalarinda sunulamaz. Izin icin Mr. Abbott'a Rob.Abbott@opg.com adresinden ulasabilirsiniz.

Seminer Ingilizce verildigi icin ve bazi teknik terimlerin tercumesinde hata yapabilirim endisesiyle slaylari da Ingilizce yayinliyorum.

The following slides were prepared and presented by Mr. Rob Abbott at a technical seminar held at Ontario Power Generation (OPG) on March 26, 2004. The slides cannot be copied or published without the written permission from Mr. Abbott. You can Mr. Abbott at Rob.Abbott@opg.com. OPG does not carry any responsibility for the information provided herein.

Slide 1: Purpose

Slide 2: Units

Slide 3: Heat Rate

Slide 4: Cogeneration

Slide 5: Fuels

Slide 6: NOx

Slide 7: Acronyms

Slide 8: Jargon

Slide 1: Purpose

	nDiscuss some commonly used terms and jargon.
	nIdentify some potential pitfalls.
	nLess than precise definitions; purpose is to just understand the concept.
	nStill be confused - just understand why.

Slide 2: Units

Btu (British thermal units)

nA measure of energy, usually in the form of heat (or cooling).

nIn the case of fuel, the potential heat energy.

n1 Btu = the amount of energy required to heat 1 pound of water, 1 degree Fahrenheit.

J (joules) The metric measure of energy.

M Potentially, very confusing can mean a million or a thousand:

	1.For most things, such as electricity or money, it means one million, or mega, e.g. MW (megawatts).
	2.The natural gas industry uses the M (or m) prefix for one thousand (as in the Roman Numeral), e.g. 1 MBtu means one thousand Btu, and 1 MMBtu means one million Btu.

Ton

	1.In the US, it means 2,000 pounds – often referred to as a short ton.
	2.In the Imperial Measure, it means 2,200 pounds - often referred to a long ton.
	3.In the cooling industry, it means 12,000 Btu/h (about the capacity of a window air conditioner).

Tonne 1,000 kilograms (which equals 2,205 pounds, close to a long ton) - often referred to as a metric ton.

Slide 3: Heat Rate

Heat rate = Fuel In ÷ Electricity Out

	ØExpressed in Btu/kWh or kJ/kWh
	ØFuel input in Btu (or kJ) electricity output in kWh
	ØFuel consumption rate of power plant

Inverse of Efficiency: Higher the number, the worse (less efficient)

tTypically: 7,000 – 12,000 Btu/kWh (6,600 – 11,000 kJ/kWh)

Analogy: nCar fuel consumption rating in litres per 100 km

Why needed? Because “easy” to figure out how much fuel you need or fueling cost, e.g.

	nTo generate 8,000 MWh of electricity in a unit with a heat rate of 7,000 Btu/kWh, will need:
	n8,000 MWh x 1,000 kW/MW x 7,000 Btu/kWh = 56 x 109 Btu, or 56,000 MMBtu, of fuel.
	nIf the fuel price is $7.00/MMBtu, this will cost 7 x 56,000 = $392,000.
	nSimilarly, to calculate the fueling cost for electricity with fuel at $7.00/MMBtu in a plant with a heat rate of 7,000 Btu/kWh: $7.00/MMBtu ÷ 1,000,000 Btu/MMBtu x 7,000 Btu/kWh = $0.49/kWh = $49/MWh

Watch out for:

n1. Boundaries for where the fuel in and electricity out is defined, e.g.

	ØTurbine heat rate - at the turbine and generator boundaries
	ØUnit heat rate - net of electricity and fuel used to operate the unit
	ØPlant or station heat rate – net of station fuel and electricity uses.

n2. Higher heating value versus lower heating value of fuel nUnits

ØUsually in Btu/kWh or kJ/kWh, the difference being about 5%

n3. Actual or corrected to some standard condition

n4. Time Basis – average, instantaneous, or incremental

n5. Cogeneration quasi-heat rates:

	ØFuel charged to power
	ØClass 43.1 heat rate

Slide 4: Cogeneration

What is it? The production of two or more forms of useful output energy in a combined process.

ne.g. your car engine moves the car, makes electricity for the lights and accessories, and heats and cools the interior

	nIn most references, the two energy forms are electricity and heat (as steam)
	nSometimes called combined heat and power (CHP)
	nProduction of one form of energy is often dependent on the other

What it isn’t, necessarily.

	nprivate power
	nuse a single fuel
	nnatural gas fired or gas turbine based
	ncombined cycle
	nalways high efficiency
	nwaste heat recovery
	nnew technology
	ndistributed generation

Irrelevant cogeneration baffle-gab

	nTri-generation (electricity, heating and cooling)
	nEnhanced combined cycle
	nBottoming cycle or topping cycle
	nSteam host (usually a steam user or steam customer)

Slide 5: Fuel

What Kind?

	Methane: Essentially, natural gas.
	Syngas: A gas synthesized, usually from a solid or liquid fuel, primarily made up of carbon monoxide, hydrogen and carbon dioxide.
	Biogas: A mixture of methane, carbon dioxide, water vapour and other gases that come from a sewage treatment plant.
	Refuse Derived Fuel (RDF), Waste Derived Fuel (WDF): Euphemisms for garbage as a fuel
	Coke: Essentially carbon, but usually also has high levels of sulphur. Think of charcoal briquettes.

Don't be Fuelled! Lower Heating Value (LHV) versus Higher Heating Value (HHV)

	nHydrogen molecules in the fuel form water vapour when burned (see the white plume from a car’s tailpipe in the winter).
	nThe energy in fuel can be expressed either on a total energy conversion basis (higher heating value), or net of the energy in the water vapour (lower heating value).
	nThe difference between the two is a function of the hydrogen in the fuel. For natural gas is about 11%, and for oil about 6%.
	nFuel pricing and most calculations are done on a higher heating value basis. However, gas turbine and engine manufacturers usually rate their machines on a lower heating value basis. The heat rate, efficiency and fuel consumption numbers appear better (11% for natural gas) on a lower heating value basis. This can create all sorts of confusion and errors, as rarely is it stated whether numbers are on a higher or lower heating value basis.

It’s Not The Heat, It’s The Humidity: Wet (as fired) or Dry?

nSolid fuels, such as coal, wood, and garbage, and even some gases such as biogas, contain a fair bit of moisture. Since this is a variable that can change day to day, the weight or volume of water is excluded when the fuel is described on a “dry” basis.

Slide 6: NOx

What is NOx? It is no Laughing Matter

	nNitrogen oxides NO, NO2, NO3… hence, the term NOx. Nitrogen from the air (air is mostly nitrogen) plus oxygen (also from the air), in the presence of very high temperatures during the combustion process, produce NOx.
	nCauses that brown streak you see above the city on a sunny day.
	nWith precipitation can form nitric acid – acid rain.

NOx Controls

n1. Reduce the oxygen

Øprovide just enough air to allow the combustion and there won’t be any “excess” oxygen in the flame to form NOx.

n2. Reduce the temperature

	ØStaged combustion – stage the combustion out over a wider area or time to eliminate the high temperatures
	ØSteam, water, flue gas, or air injection into the hot spots of the flame to lower the temperature

n3. SCR (Selective Catalytic Reduction)

ØAdd ammonia in the presence of a catalyst at the right conditions and turn the NOx into nitrogen (N2) and water.

Watch out for:

	nOntario (Canada's province) generally reports NOx level as NO. Whereas the rest of the world reports it as NO2. Levels are about 30% lower when reported as NO versus NO2.
	nWhile excess air or O2 level increases the NOX production it also has a dilution effect on the measured levels. Therefore, NOX levels are often reported corrected to a specific excess air (or O2) level.
	nVarious units, e.g. parts per million (ppm), g/kWh, lb/MMBtu, car equivalents, etc.
	nGround level versus stack values.

Slide 7: Jargon (You say Potato, I say Solanum Tuberosum)

Operation Jargon: Reliability, Availability, Outages

Reliability

	1.Generic term that covers a multitude of statistical calculations related to outages.
	2.A specific measure of performance, usually expressed as a percentage: the operating hours ÷ period hours

Availability

The percent of time a unit is available to operate, regardless whether it does or not: (the period hours – the hours broken) ÷ period hours. Your car is presumed to be available when parked.

Outages

There can be many reasons why a power plant is not operating, or on an outage, but if it’s not still available to operate, these generally fall under two categories:

	Forced: Unexpected – little or no advance warning (#*&% Happens)
	Planned or Scheduled: Expected – usually for routine and preventative maintenance.

Electro-Speak as a Second Language

Vars, Mvars, Reactive Power

Represent the power or energy stored and released in magnetic fields. On the one hand, because the energy is stored, it isn’t really lost, so it is sometimes referred to as “imaginary power”, but because there is a time delay associated with the storage and retrieval of this energy, it impacts the “real power”, or MW. Also, just like bank fees, there are losses associated with this storage and retrieval of reactive power.

Foofoo Valve

A very specialized doodad that facilitates alignment of the warp coil relays to the plasma flux injectors; typically the cause of an extended outage. However, if you did not opt for the expensive foofoo valve option, it is the reason your plant is out of service. Car dealers replace a lot of foofoo valves.

Rest of Jargon

Back Pressure: This is the steam pressure at the exhaust (back end) of a steam turbine, usually at the condenser.

Blowdowns: Hot water bled off from the boiler (or HRSG) to prevent the formation of scale and deposits.

Exciter: A gizmo that makes the electricity, that energizes the magnets, that make the electricity in a generator, that fries the egg, that came from the chicken, that...

Flashing: When hot, high pressure water has a sudden loss in pressure, it can turn to steam, or flash. This is what happens when your radiator boils over.

Head: For hydroelectric plants this refers to the difference in elevation between the water level at the inlet and outlet of the plant. For pumps it is related to the difference in pressure between the inlet and outlet.

Slide 8: Acronyms

CCW: Condenser Circulating Water - cooling water used to condense steam.

FD Fan: A large fan used to feed combustion air into a boiler.

FGD: Flue Gas Desulphurization or Scrubber - A device which removes sulphur (SO2) from the flue gas.

GT,CT, CTU: Gas Turbine, Combustion Turbine, and Combustion Turbine Unit, respectively. These all mean the same thing.

HP, IP, LP: High Pressure, Intermediate Pressure and Low Pressure

HRSG (her-sig): Heat Recovery Steam Generator, that captures the heat from the exhaust of a gas turbine and generates steam.

ID Fan: A large fan used to draw flue gas out of the boiler and push it up the stack.

PF: Pulverized Fuel - essentially coal dust.