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SIKLUS DI BOILER

Oleh

Dr.-Ing. Anton Irawan, ST., MTTeknik Kimia

Fakultas Teknik – Universitas Sultan Ageng Tirtayasa

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What is a Boiler?

© UNEP 2006

Introduction

• Vessel that heats water to become hot water or steam

• At atmospheric pressure water volume increases 1,600 times

• Hot water or steam used to transfer heat to a process

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Introduction

BURNERWATER

SOURCE

BRINE

SOFTENERSCHEMICAL FEED

FUELBLOW DOWN SEPARATOR

VENT

VENTEXHAUST GASSTEAM TO PROCESS

STACK DEAERATOR

PUMPS

Figure: Schematic overview of a boiler room

BOILER

ECO-NOMI-ZER

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Introduction

Type of boilers

Assessment of a boiler

Energy efficiency opportunities

© UNEP 2006

Training Agenda: Boiler

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© UNEP 2006

Types of Boilers

1. Fire Tube Boiler

2. Water Tube Boiler

3. Packaged Boiler

4. Fluidized Bed (FBC) Boiler

5. Stoker Fired Boiler

6. Pulverized Fuel Boiler

7. Waste Heat Boiler

8. Thermic Fluid Heater (not a boiler!)

What Type of Boilers Are There?

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© UNEP 2006

Type of Boilers

(Light Rail Transit Association)

1. Fire Tube Boiler

• Relatively small steam capacities (12,000 kg/hour)

• Low to medium steam pressures (18 kg/cm2)

• Operates with oil, gas or solid fuels

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Type of Boilers

2. Water Tube Boiler

(Your Dictionary.com)

• Used for high steam demand and pressure requirements

• Capacity range of 4,500 – 120,000 kg/hour

• Combustion efficiency enhanced by induced draft provisions

• Lower tolerance for water quality and needs water treatment plant

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Type of Boilers

(BIB Cochran, 2003)

3. Packaged Boiler

Oil Burner

To Chimney

• Comes in complete package

• Features• High heat transfer• Faster evaporation • Good convective

heat transfer• Good combustion

efficiency• High thermal

efficiency

• Classified based on number of passes

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Type of Boilers

4. Fluidized Bed Combustion (FBC) Boiler• Particles (e.g. sand) are suspended in high

velocity air stream: bubbling fluidized bed

• Combustion at 840° – 950° C

• Capacity range 0,5 T/hr to 100 T/hr

• Fuels: coal, washery rejects, rice husk, bagasse and agricultural wastes

• Benefits: compactness, fuel flexibility, higher combustion efficiency, reduced SOx & NOx

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Type of Boilers

4a. Atmospheric Fluidized Bed Combustion (AFBC) Boiler

• Most common FBC boiler that uses preheated atmospheric air as fluidization and combustion air

4b. Pressurized Fluidized Bed Combustion (PFBC) Boiler

• Compressor supplies the forced draft and combustor is a pressure vessel

• Used for cogeneration or combined cycle power generation

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Type of Boilers

(Thermax Babcock & Wilcox Ltd, 2001)

4c. Atmospheric Circulating Fluidized Bed Combustion (CFBC) Boiler

• Solids lifted from bed, rise, return to bed

• Steam generation in convection section

• Benefits: more economical, better space utilization and efficient combustion

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Type of Boilers

5. Stoke Fired Boilers

a) Spreader stokers• Coal is first burnt in suspension then in

coal bed

• Flexibility to meet load fluctuations

• Favored in many industrial applications

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Type of Boilers

5. Stoke Fired Boilers

b) Chain-grate or traveling-grate stoker

(University of Missouri, 2004)

• Coal is burnt on moving steel grate

• Coal gate controls coal feeding rate

• Uniform coal size for complete combustion

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Type of Boilers

Tangential firing

6. Pulverized Fuel Boiler

• Pulverized coal powder blown with combustion air into boiler through burner nozzles

• Combustion temperature at 1300 -1700 °C

• Benefits: varying coal quality coal, quick response to load changes and high pre-heat air temperatures

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Type of Boilers

Agriculture and Agri-Food Canada, 2001

7. Waste Heat Boiler• Used when waste heat

available at medium/high temp

• Auxiliary fuel burners used if steam demand is more than the waste heat can generate

• Used in heat recovery from exhaust gases from gas turbines and diesel engines

PROSES PRODUKSI LISTRIK DI PLTU

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1-2 Kompresi isentropi pada pompa2-3 Penambahan panas pada tekanan tetap di boiler3-4 Ekspansi isentropi pada turbin4 -1 Pengeluaran panas pada tekanan tetap di kondensor

SIKLUS RANGKINE

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EFISIENSI THERMAL

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KETIDAK IDEALAN SIKLUS RANKINE

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PENINGKATAN EFISIENSI THERMAL

Penurunan Tekanan Kondensor Peningkatan temperatur steam keluar Peningkatan tekanan boiler

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Penurunan Tekanan Kondensor

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Penurunan tekanan kondensor akan menyebabkan terjadinya peningkatan kerja yang dihasilkan pada turbin tetapi juga menyebabkan peningkatan kerja yang diberikan pada pompa tetapi bila dilihat dari luas area maka peningkatan kerja yang dihasilkan oleh turbin lebih besar

Peningkatan Temperatur Steam

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Peningkatan temperatur steam yang masuk ke turbin akan meningkatan kerja yang dihasilkan oleh turbin. Material yang tahan temperatur tinggi perlu dipertimbangkan

Peningkatan Tekanan di Boiler

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Peningkatan temperatur steam dapat dilakukan dengan peningkatan tekanan di boiler tetapi menyebabkan moisture pada

keluaran turbin

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SIKLUS RANKIN DENGAN PEMANASAN

KEMBALI

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