STEAM POWER PLANT

Dr. Ir. Adi SurjosatyoDTM FTUI

Februari 2005

Kuliah III

ReferensiSteam its generation and use (Babcock & Wilcox- a Mc Dermot company)

Fundamental SteamTHERMODYNAMIC PRPROPERTIES

DefinisiTemperature is an intensive property that depends on energy content. Heat energy entering a substance increases the temperature of that substance. Heat energy flows only from a hot object to a cold object .

Celcius dan Fahrenheit scale.Pressure is the force per unit area exerted on or by a fluid. In engineering practice, typical units are pounds per square inch (psi) [pascals (Pa)]. Most steam cal culations require the use of absolute pressure, commonly denoted as psia (pounds per square inch absolute).Density of a body is its mass per unit volume, with units of pound mass per cubic foot (lbm/ft3) [kilograms per cubic meter (kg/m3)]. The reciprocal of density, referred to as specific volume, is often required in steam calculations.

THERMODYNAMIC PRPROPERTIES

Substances differ, in the quantity of heat needed to produce a given temperature increase. The ratio of heat to the temperature change is called the specific heat of the substance:

c= Q/mTwhere

c c = specific heat, Btu/(lbm - °R)[caU(g - K)], Q = heat, Btu (cal), m = mass, lbm (g), T = temperature, °R (K)

Sensible heat is the energy added to a substance that changes its temperature. The amount of heat required depends on the temperature and the specific heat of the substance.Latent heat is the energy added to a substance that produces a change in phase without causing a temperature change. Examples of latent heats are melting, vaporization, and sublimination.

THERMODYNAMIC PRPROPERTIES

Internal energy encompasses all the potential and kinetic energies of the atoms or molecules in a substance. Energies in the translational, rotational, and vibrationat modes are included. Since this movement increases with temperature, inter nal energy is a function of temperature.Enthalpy is a property that represents the total useful energy in the sub stance. Useful energy consists of two parts: the internal energy and the flow energy.

h =_u+pv/J; where

h = enthalpy, Btu/lbm (cal/g)u = internal energy, Btu/ibm (cal/g) p = pressure, psia (Pa)J = Joule's constant = 778 ft -lbf/Btu = 1

N/m v = specific volume, ft3/Ibm (cm3/g)

THERMODYNAMIC PRPROPERTIES

Entropy defined as a measure of the degree of disorder of a system. This definition and its implications for the steam cycle are discussed later in this chapter under the second law of thermodynamics. For purposes of steam calculations, entropy is defined as a measure of the energy that is no longer available to perform useful work within the current environment.Mollier diagram, which is a graph of enthalpy versus entropy for steam.Ideal Gas Laws: p1/v1 = p2/v2 ; pV= RT

R = specific gas constant, ft - lbfl(Ibm - °R)[kJ/(kg - K)]. For superheated steam, R = 85.8 ft - lbf/(lbm - °R).

First Law of Thermodynamics Q=∆U+W Q = heat input, Btu (J); U = internal energy, Btu (J) W =

work output, Btu (J)

Second Law of Thermodynamics IrreversibleEntropy concept

STEAM POWER CYCLES • Isothermal->constant temperature • Isobaric-

>constant pressure • Isometricconstant volume • Isentropic-constant entropy

• adiabatic->no heat transfer• Throttling->constant enthalpy

Thermal Efficiency thermal efficiency %. The desired energy output is the shaft work, and the energy that it costs is the heat input to the boiler.

Camot Cycle The Carnot cycle is a four-process cycle that has two reversible isothermal processes for heat addition and heat rejection to the environment. Because the processes are reversible, the maximum thermal efficiency for a Carnot cycle can be defined strictly by heat source TH and heat

sink TL, temperatures ηth = 1- TH/TL

Simple Rankine Cycle

Advance Rankine Cycle

Tugas-TugasDiskusi Kelompok yang berkaitan dengan Sistim Pembangkit Daya:

Bertujuan meningkatkan kemampuan mahasiswa dalam menganalisa masalahKemungkinan ide-ide berupa solusi berdasarkan referensiMeningkatkan kerjasama tim dan meningkatkan kemampuan baca mahasiswa

Topik-topik bahasanSumber-sumber energi bagi sistim pembangkitan DayaKemungkinan Jenis-jenis Teknologi yang digunakan dalam Power PlantApakah pengaruh pemilihan teknologi bagi Power Plant berkaitan dengan menipisnya sumber Energi BBM ataupun B.bara

Topik Bahasan (lanjutan)Pengaruh jenis Batu bara terhadap Pembakaran di Boiler (effisiensi, dimensi ruang bakar dll)Perkiraan-perkiraan pemanfaatan energi Alternatif sebagai sumber bahan bakar untuk existing Boiler di Indonesia. (Cari informasi spesifikasi boiler yang ada di Indonesia)

Water Tube Boiler

Water Tube Boiler DesignFurnaceSteam Super heater (primary & Secondary)Boiler atau Steam Generating BankEconomizerSteam DrumAttemperature atau Steam temperature control system

Boiler circulation system

a)Simple Circ.Syatem b) Forced circ. System

Effect pressure on pumpinghead

Sub critical pressure drum boile

Kriteria desain Desain Ketel

Tentukan input energy sesuai kebutuhan aliran uap, temperatur air pengumpan (feedingwater), asumsi effisiensi termal Evaluasi energy yang diabsorpsi oleh boilerTentukan ukuran dan bentuk furnace, lokasi burner dlldll