TECHNICAL TRAINING For Coal Boilers

TECHNICALTRAININGForCoal Boilers

Matt ZedlerProduct

Development

January 22 Rev0

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What is a POWER PLANT?A power plant is a factory that is used to manufacture electric power.Power is energy that is used to produce work. Electric power is sent through wires

where it can be used to spin motors, light lights, or for many other uses!Power plants can convert chemical energy in fuel (coal, gas, oil, nuclear) to electric

power, or they can capture energy present in other forms (wind, water, solar)

Background & History

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Agenda

Coal Boiler Basic TrainingBackground & History

Boiler ComponentsBoiler Types

Further Learning

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What is a BOILER?“Boiler” = steam generator; uses heat to change water to steam

• Heat can come from a variety of sources (coal, oil, gas, biomass, uranium, solar energy)

• Typically divide the fossil-fueled boiler into two main systems:1. 炉 - Fuel & fire side (fuel & air handling, combustion, radiation and convection

heat transfer, exhaust) 2. 锅 – Water & steam side (feedwater pumps, tubes & downcomers, drum)

Used for power generation, municipal heating, industrial applications, etc.

Can be stationary or mobile (package boiler, boilers on ships)


锅 (guo1) means “pot”

炉 (lu2) means “furnace”

Even the energy of the sun can be used to make

steam in a boiler!

The hot exhaust from combustion can be used to generate steam in a “heat recovery steam generator”

(HRSG)

Fossil fuels are burned in boilers

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Boiler History• Greeks first used steam to drive a simple toy in 200 BC• Serious development began in 1600s AD• England led the world in steam power development during the

industrial revolution• Limited by materials – as steel became available, boilers could

go to higher temperatures and pressures




Early 1700s kettle-type boiler

1800s Babcock & Wilcox boiler

Modern subcritical boiler

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Fire-Side ( 炉 )• Any fossil fuel requires oxygen to combust• Simply put, the furnace is simply a container for air and

fuel to mix, combust, and release heat• Pulverized fuel and air are pushed into the bottom of the

furnace by fans (forced draft), and hot exhaust is pulled out of the back of the furnace by different fans (induced draft)

• Heat is released in the “front pass” primarily through radiation (tubes “see” the fire)

• In the “back pass,” heat is released through convection (tubes “feel” the heat as hot gas passes over them)

• Burning fuel releases tremendous heat (2000°C temperatures), melting any solids in the fuel

• Combustion also releases pollutants:• Nitrogen oxides (NO, NO2 = NOx) – causes smog• Sulfur oxides (SO3 = SOx) – causes acid rain• Particulate matter – small amounts of solids• Mercury (Hg) – poisons water supplies• Carbon dioxide (CO2) – greenhouse gas

Boiler Components


Fuel (chemical) energy is changed to heat in the FURNACE

Looking down in furnace of corner-fired unit

Heat is released in FRONT and BACK passes of the boiler

FRONT

BACK

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Fire-Side ( 炉 ): Air• Large fans are needed to move the amount of air

required for burning coal – each kilogram of coal typically requires 6 to 8 kilograms of air

• Forced draft fans (FDFs) pull in ambient air. Ducts are used to move the air to the boiler. The windbox is the final section of ductwork that connects to the burners. An air preheater (APH) can be used to take waste heat from the exhaust and heat incoming air.

• Air is also used to move pulverized coal. Air with coal is called primary or tertiary air while air with no coal is called secondary air.

Boiler Components

FDF Side View

A 60 megawatt (MW)* power plant requires 220 metric tons per hour of steam. To produce the

steam, 37 metric tons per hour (37,000 kg/hr) of coal are required. Therefore, roughly 260,000 kg/hr of

air are required (7 x 37,000 kg/hr). That’s roughly 56 m3 of ambient air

every second!!*One megawatt is 1,000,000 watts. Therefore, a 60 MW

plant makes enough power to light 600,000 100 W light bulbs!

AIR IN

AIR

OU

T

AIR

OU

T

FDF, Showing Motor

APH (Single pass)Hot gas gives heat

to cooler air

Ductwork is LARGE – lots of air!

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Fire-Side ( 炉 ): Fuel• Solid fuel burns best when crushed to a very fine

powder (pulverized – 60% to 70% of coal entering a boiler is less than 75 microns in diameter!

• Fuel is moved by conveyors, crushed, and then pulverized in several mills.

• Mills use steel balls, rollers, or some sort of grinding element to pulverize the coal.

• Air can then be used to convey pulverized coal to the burners.

Boiler Components

FDF Side View

Coal passing through a vertical

pulverizer is crushed by rollers

Crushed coal going into a storage bin

Pulverized coal is like a fine dust – make sure not to breath too much in!

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Fire-Side ( 炉 ): Fuel (Direct vs Indirect)There are two main milling system configurations in use:

• DIRECT – Primary air that enters the mill is used to then carry the coal to the burner (no tertiary air)

• INDIRECT – After the coarse classifier, coal is separated from the air after and stored in a bin. Primary air is used to convey coal from the bin to the burner. The tertiary or milling air may either be used in the boiler or recirculated to the mill.

Boiler Components

FDF Side View Indirect SystemDirect System

A classifier is a piece of equipment that ensures

particles that are too large (typically over 300

microns) are not sent to the boiler.

The classifier can be internal to the mill (direct system) or external to the

mill (indirect system’s coarse classifier)

LP Amina has a patented classifier technology.

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Fire-Side ( 炉 ): Burners (Air + Fuel)• Coal and air are mixed and ignited in the burner zone.• Burners come in many different sizes and shapes, but the primary

goal is ensure proper mixing. Poor mixing leads to incomplete combustion (typically represented by a large point of unburnt carbon or UBC).

• Burners must be able to withstand very high temperatures, typically for several years of operation.

• The tip of the burner is called the nozzle. Nozzles can sometimes tilt to raise or lower the location of the main combustion zone.

Boiler Components

FDF Side View

Nozzles are typically labeled using letters, starting at the bottom of the

burner column and moving up.

Nozzles that have fuel are given a single letter (A, B, C…). Nozzles

that are only air are labeled by the coal nozzles they are between (AB

would be the air nozzle between coal nozzles A & B).

Drawing of a wall-fired burner

Tangent-fired burner column (nozzles visible)

Burner pipe spares

Burnt-up coal nozzle

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Water-Side ( 锅 )• Complex system of tubes and pipes that gather

heat from the furnace to change water to steam• Water (feedwater) is pumped to the steam drum at the top

of the boiler, passing through the economizer on the way• Downcomers and headers carry water to the bottom of the

boiler.• Water flows upwards to the steam drum through the

membrane wall, absorbing heat and changing to steam.• Steam exits the steam drum at desired temperature and

pressure• Steam drum separates steam and water in a

subcritical boiler. There is no steam drum in a supercritical boiler (water is so hot and at such a high pressure it simply turns into steam without boiling)

• Steam is typically at 13 – 17 MPa and 540°C in subcritical boilers

Boiler Components

锅 (guo1) means “pot” (pot is made of many tubes)

Heat is collected and transferred to the end use in the water-steam system.

Nozzle opening in tube (membrane) wall


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Water-Steam System( 锅 : 水气系统 )

Boiler Components

The “pot” is very complex – boiler manufacturers want as much heat transfer as

possible in a small area to save costs

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Water-Steam System( 锅 : 水气系统 )

Boiler Components

Boiler uses fuel to change chemical energy into heat

energy

Steam turbine converts heat to mechanical energy

Steam turbine is fan spinning at 3,000 – 3,600 RPM

Steam condenses back to water in the condenser

Some hot water may go for district heating

Natural convection cooling

Air cooled condenser

Once-through river / lake cooling

LOOP 1

MAKE STEAM

LOOP 2

COOL STEAM

Two separate water loops at all thermal power plants – Loop 1 water quality very important

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• Boiler design is determined primarily by the following:1. Desired output steam conditions (pressure, temperature, flow rate)2. Fuel type

• Biggest differences are typically in boiler size and burner arrangement

Boiler Types

Coal Boiler Types

TYPETangentially-fired

(四角 )Wall-fired

(墙式 )Down (W)-fired Continuous

Fluidized Bed (CFB)

BURNER LOCATION

In four corners, arranged to create a rotating fireball

in furnace

In one, two, or four of the walls

Angled downwards. Combustion gases form a

“W”.

No burners

WHERECommon in China,

especially for smaller units

Common in US (B&W)

Not many in US or China

Areas where high sulfur coal is burnt

WHYCheap and easy Better

exhaust gas uniformity

Burning anthracite (hard

coal)

Burning high-sulfur coals

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Boiler Types

Coal Boiler Types

Corner / Tangent-Fired Unit Wall-Fired Unit

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Further Learning

ReferencesMaterial for this training was primarily taken

from the following sources, as well as the Internet and personal photo archives:

• Kitto, J.B. & Stultz, S.C. Steam: Its Generation and Use (Ed.41). Babcock & Wilcox Company. USA : OH, Barberton (2005).

• Drbal, L.F. Power Plant Engineering. Black & Veatch. USA : NY, New York (1996).

LP Amina is working on putting together more detailed technical references and trainings and would welcome any comments or feedback. Please direct any suggestions to M. Zedler in Product Development.

燃煤锅炉技术培训

产品研发部马修文现场服务部陈福兵2013 年 01 月 26 号 0 修改

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什么是电厂电厂是用来发电的工厂。电力是生产工作的能量来源。电能通过电线传输，具有提供动机所需动力、提供照明等诸多用途 .

电厂可以将储藏在燃料（煤、天然气、石油、原子核）里的化学能量转化成电能，或利用其他形式（风、水、太阳）的能量。

背景与历史

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Agenda

燃煤锅炉 - 技术培训背景与历史锅炉部件锅炉型进一步学习

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什么是锅炉？锅炉 = 蒸汽发生器，通过热能将水转化为蒸汽• 热能来源广泛（煤、石油、天然气、生物、铀、太阳能等）• 一般将化石燃料锅炉分为两大系统：

1. 炉 – 燃料和火焰（烟风）（燃料与空气处理、燃烧、热辐射与对流传热、废物）2. 锅 – 水和蒸汽（给水泵、管道和下降管、集箱）

用于发电，城市供暖、工业应用等分为静态和动态（整装锅炉、作为轮船动力的锅炉）

背景与历史



Even the energy of the sun can be used to make

steam in a boiler!

The hot exhaust from combustion can be used to generate steam in a “heat recovery steam generator”

(HRSG)

Fossil fuels are burned in boilers

21

锅炉简史• 公元前 200 年，希腊人首先利用蒸汽推动一个简单的玩具• 公元 1600 年后，对蒸汽用途的严肃研究拉开了帷幕• 工业革命时期，英国引领世界进行蒸汽发电研发• 起初受限于材料，后来随着钢材的出现，锅炉可以达到更高的温度和压力。

背景与历史



Early 1700s kettle-type boiler

1800s Babcock & Wilcox boiler

Modern subcritical boiler

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Fire-Side ( 炉 )• 任何化学燃料都需要氧气进行燃烧• 简言之，炉就是空气与燃料混合、燃烧并释放热能的容器。

• 通过送风机（强制通风）将煤粉和空气送入炉底部，热废气通过引风机（诱导通风）从炉后排出。• 在前炉膛（水冷壁）主要以辐射换热为主（即：火焰和高温烟气没有与管道接触）• 在后炉膛主要以对流换热为主（在高温烟气通过时，直接冲刷管道）

• 燃烧燃料产生很高温度（ 2000 摄氏度），将燃料中的所有固体都熔化（如果煤颗粒在熔化前，没有被燃烧掉，就会结渣。）• 燃烧会产生的污染物：

• 氮氧化物 (NO, NO2 = NOx) – 产生烟雾• 硫化物 (SO3 = SOx)- 产生酸雨• 悬浮颗粒物 – 少量的固体颗粒• 汞 (Hg) – 污染水源• 二氧化碳 (CO2) – 温室气体

锅炉部件


Fuel (chemical) energy is changed to heat in the FURNACE

Looking down in furnace of corner-fired unit


前通过后通过

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Fire-Side ( 炉 ): 空气• 风机提供燃烧所需的空气 —— 每千克煤通常需要

6 至 8 千克空气• 送风机 (FDF) 将周边空气引入。风道将空气导入锅炉。风箱是风道系统的最后一个部分，连接燃烧器。预热器 (APH) 可以将废气中的热能传导至进入系统的空气，从而加热空气 , 在空气被燃烧之前，对其进行预热（所以叫预热器）。• 空气还用于运送煤粉。夹带煤粉的空气称为一次风或三次风，没有夹带煤粉的空气称为二次风。

FDF Side View

A 60 megawatt (MW)* power plant requires 220 metric tons per hour of steam. To produce the

steam, 37 metric tons per hour (37,000 kg/hr) of coal are required. Therefore, roughly 260,000 kg/hr of

air are required (7 x 37,000 kg/hr). That’s roughly 56 m3 of ambient air

every second!!*One megawatt is 1,000,000 watts. Therefore, a 60 MW

plant makes enough power to light 600,000 100 W light bulbs!

AIR IN

AIR

OU

T

AIR

OU

T

FDF, Showing Motor

APH (Single pass)Hot gas gives heat

to cooler air

Ductwork is LARGE – lots of air!

锅炉部件

24

Fire-Side ( 炉 ): 燃料 / 煤• 当被研磨成非常细小的粉末时，固体燃料的燃烧效果最好。（这些送入锅炉的细小粉末有 60% 至 70% 的煤粉颗粒直径小于 75微米）！• 传送器运送煤粉，煤料被压碎，并在几个磨煤机里磨成细小颗粒• 磨煤器使用钢球、辊子或者其他研磨部件研磨煤料• 空气用于将煤粉运送至燃烧器

FDF Side View

Coal passing through a vertical

pulverizer is crushed by rollers

Crushed coal going into a storage bin

Pulverized coal is like a fine dust – make sure not to breath too much in!

锅炉部件

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Fire-Side ( 炉 ): 燃料 / 煤（直接与间接）现在常见的主要有两种研磨系统结构：• 直接：一次风送入磨煤机，然后携带煤粉至燃烧器（没有三次风）• 间接：煤料在经过粗粉分离器后，与空气分离，并将其储藏在煤粉仓中。一次风用于将煤粉从煤粉仓输送至燃烧器。三次风或者研磨空气可以用于锅炉或者磨煤器再循环。

FDF Side View Indirect SystemDirect System

A classifier is a piece of equipment that ensures

particles that are too large (typically over 300

microns) are not sent to the boiler.

The classifier can be internal to the mill (direct system) or external to the

mill (indirect system’s coarse classifier)

LP Amina has a patented classifier technology.

锅炉部件

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Fire-Side ( 炉 ): 燃烧器（空气 + 燃料 / 煤粉）• 在燃烧器区域，煤粉与空气混合，并被点燃。• 燃烧器的形状大小不尽相同，但总的原则是保证正确的煤与空气的混合。混合不充分会导致不完全燃烧（最典型的是体现在大块的未完全燃烧碳上，即： UBC ）• 燃烧器应确保耐磨、耐磨损，一般为一个锅炉大修周期• 燃烧器前端称为喷嘴。喷嘴可以上下摆动来抬高或降低主燃烧区域位置。

FDF Side View

Nozzles are typically labeled using letters, starting at the bottom of the

burner column and moving up.

Nozzles that have fuel are given a single letter (A, B, C…). Nozzles

that are only air are labeled by the coal nozzles they are between (AB

would be the air nozzle between coal nozzles A & B).

Drawing of a wall-fired burner

Tangent-fired burner column (nozzles visible)

Burner pipe spares

Burnt-up coal nozzle

锅炉部件

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Water-Side ( 锅 )• 复杂的管道系统吸收燃烧炉的热量，并将水转化为蒸汽

• 将水（锅炉给水）泵入位于锅炉顶端的上汽包，途经省煤器• 下降管和联箱将水运送至锅炉底端（水冷器下集箱）• 水流经过水冷壁向上流至上汽包，吸收热量，并转化为蒸汽• 蒸汽在上汽包内达到预定的温度和压强

• 上汽包将亚临界锅炉的水蒸气和水分开。 • 超临界锅炉没有汽包（水太热了，高压下直接转化成蒸汽，无需沸腾）• 亚临界锅炉里面的水蒸气压强为

13 – 17 MPa ，温度为 300 - 540°C 。

锅 (guo1) means “pot” (pot is made of many tubes)

Heat is collected and transferred to the end use in the water-steam system.

Nozzle opening in tube (membrane) wall


锅炉部件

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Water-Steam System( 锅 : 水气系统 )The “pot” is very complex – boiler

manufacturers want as much heat transfer as possible in a small area to save costs

锅炉部件

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• 锅炉设计首先有以下因素确定：1. 预期输出蒸汽条件（压强、温度、流速）2. 燃料类型

• 锅炉间差异的最主要因素是大小和燃烧器布置

锅炉型

燃煤锅炉型号

TYPE型号 Tangentially-fired (四角 )

Wall-fired (墙式 )

Down (W)-fired Continuous Fluidized Bed (CFB)

燃烧器位置

四角，造成炉内旋转火焰

在一面、两面或四面墙

上向下转形成 W

型火焰” .无燃烧器

使用区域中国常见，尤其常见于小机组

美国常见美中不常见燃烧高硫煤区域

原因便宜、方便废气均匀度好

燃烧无烟煤燃烧高硫煤

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燃煤锅炉型号

Corner / Tangent-Fired Unit Wall-Fired Unit

锅炉型

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进一步学习

参考文献以下为此培训材料的参考文献，包括一些专著、网上和个人图片库。• Kitto, J.B. & Stultz, S.C. Steam: Its

Generation and Use (Ed.41). Babcock & Wilcox Company. USA : OH, Barberton (2005).

• Drbal, L.F. Power Plant Engineering. Black & Veatch. USA : NY, New York (1996).

阿米那正在备至更加详尽的培训材料，并欢迎大家评论与反馈。请直接联系产品研发部马修文。

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TECHNICAL TRAINING For Coal Boilers