waste heat recovery in cement industry at mapl leaf cement factory

Waste Heat Recovery Power Plant M.L.C.F.L. Mianwali

Training Report

Muhammad Tafseer Abbas

Acknowledgement

All thanks and praises to Allah. The Almighty who helps in solving our difficulties. Allah

is the source of all knowledge. He gave me the wisdom, guidance and enabled me to undertake

and complete this work.

Waste Heat Recovery Power Plant Maple Leaf Cement Factory Mianwali

Dedication

I would like to dedicate the report to Waste Heat Recovery Power Plant Erection team who

guided me throughout my training period and still doing their best for me. To be here in this

organization and working with such a hard work team at this level is a matter of proud for me.


Vision

“In order to remain competitive in the market the management at Maple Leaf continuously re

evaluates its business strategies. With the increase of furnace oil prices the company adopted

coal as a more cost efficient and environmentally friendly fuel for kiln firing. Today the

management believes that the future lies in exploring the possibilities of alternative and cheaper

fuels such as waste firing. This would further reduce production costs whilst promoting a culture

of environmental awareness, health and safety.”


Mission Statement

“To develop and implement good practices in the field of development and management

of people, for application both by professional members and the community within

M.L.C.F.L.”

“To serve the professional as well as the social interest of the personnel at M.L.C.F.L.”

“To uphold the highest ideals in the management and development of people.”


Contents

Executive Summary --------------------------------------------------------------------------9

1 Maple Leaf Cement Factory ---------------------------------------------------------------10

2 Introduction to Cement and Green House Gases----------------------------------------11

3 Clean Development Mechanism Overview ----------------------------------------------12

4 Waste Heat -----------------------------------------------------------------------------------16

5 Development of a Waste Heat Recovery System ---------------------------------------17

6 Waste Heat Recovery in M.L.C.F.L. Iskanderabad ------------------------------------20

7 Power Output --------------------------------------------------------------------------------31

8 Health Safety and Environment -----------------------------------------------------------35


List of tables

Table-1 Technical specifications of Heat Recovery units---------------------------30

List of Figures

Fig-1 Location Map of Maple Leaf Cement Factory Limited----------------------10

Fig-2 Gas Flow Diagram of Cement Plant--------------------------------------------18

Fig-3 Gas Flow Diagram in Cement Plant and WHRP-----------------------------19

Fig-4 Waste and Effective Energy Comparison--------------------------------------21

Fig-6 Block Diagram of WHRPP with Two Cement Lines------------------------26

Fig-7 Block Diagram of WHRPP with Two Cement Lines and Wartsila--------29

Fig-8 Inputs to Waste Heat Recovery Power Plant----------------------------------31

Fig-9 Complete Block Diagram of WHRPP with GCD and Wartsila ------------33

Fig-10 Power Flow Diagram of WHRPP System------------------------------------34


List of Abbreviations

AQC1 Air Quenching Cooler Line 1

AQC2 Air Quenching Cooler Line 2

CDM Clean Development Mechanism

CER Certified Emission Reduction

DSM Demand-side Management

ERUs Emission Reduction Units

GHG Greenhouse gas

ISO International Organization for Standardization

I/P Input

JI Joint Implementation

JISC Joint Implementation Supervisory Committee

M.L.C.F.L. Maple Leaf Cement Factory Limited

MW Megawatt

PH1 Preheater Line 1

PH2 Preheater Line2

UNFCCC United Nations Framework Convention on Climate Change

WHRPP Waste Heat Recovery Power Plant

WHRB Waste Heat Recovery Boiler


Executive Summary

he quest for higher efficiencies has spurred the innovation of energy efficient technologies

such as waste heat recovery. The recovery and utilization of waste heat not only conserves

fuel, usually fossil fuel, but also reduces the amount of waste heat and greenhouse gases dumped

to the environment. Waste Heat Recovery (WHR) is an energy efficient technology that promises

a financially viable and environment-friendly option in demand-side energy management

(DSM).

T

5% of global carbon dioxide emissions originate from cement production. About half of it from

calcination and half of combustion processes. Waste heat recovery is an option to reduce CO2

emissions considerably.

Waste heat from the flue gases are estimated to provide a total of 13.9 MW for the factory’s

additional Electrical energy requirement.

The Clean Development Mechanism (CDM) is one of the several financing options considered

for the proposed project. CDM is one of three mechanisms established by the Kyoto Protocol and

allows emission reduction projects that assist developing countries in achieving sustainable

development and that generate “Certified Emission Reduction” (CER) for use by the investing

country or company.

Considering the above, the project is beneficial, viable and worth implementing. The company

will realize increased profits and employment from expanding operations while contributing to

the protection of the environment. The feasibility study has shown than as an energy efficient

demand-side option, waste heat recovery promises a large potential for energy savings, foreign

exchange savings and greenhouse gas abatement. The replication of this project in the production


of the country will stimulate investment and pave the way for cleaner economic growth and

sustainable development for the country.

1 Maple Leaf Cement Factory

aple Leaf Cement Factory Limited is the third largest cement producer in Pakistan. It

was setup in 1956 as a joint collaboration between the West Pakistan Industrial

Development Cooperation and Government of Canada. In 1992 Kohinoor Group acquired the

ownership and management of M.L.C.F.L. under the privatization policy of the Government of

Pakistan. Presently,

M

Kohinoor Group is the holding company for M.L.C.F.L.

M.L.C.F.L. is strategically located at Iskanderabad, near the city of Daudkhel, an area which is

rich in raw materials required for the production of cement. M.L.C.F.L. has an ISO

9000/9001/9004/19011: 2000 certification and manufactures high quality cement products

(Ordinary Portland Cement, White Cement, Sulphate Resistant Cement, Low Alkali Cement and

Oil Well Cement).


Fig-1 Location Map of Maple Leaf Cement Factory Limited

2 Introduction to Cement and Green House

Gases

ement is considered one of the most important building materials around the world. It is

mainly used for the production of concrete. Concrete is a mixture of inert mineral

aggregates, e.g. sand, gravel, crushed stones, and cement. Cement consumption and production is

closely related to construction activity, and therefore to the general economic activity.

C

Cement is one of the most produced materials around the world. Due to the importance of

cement as a construction material, and the geographic abundance of the main raw materials, i.e.

limestone, cement is produced in virtually all countries. The widespread production is also due to

the relative low price and high density of cement that limits ground transportation because of the

relative high costs.

The energy consumption by the cement industry is estimated at about 2% of the global primary

energy consumption, or almost 5% of the total global industrial energy consumption. Due to the

dominant use of carbon intensive fuels, e.g. coal, in clinker making, the cement industry is also a

major emitter of CO2 emissions. Besides energy consumption, the clinker making process also

emits CO2 due to the calcining process.

The cement industry contributes 5% of total global carbon dioxide emissions.


3 Clean Development Mechanism Overview

Background

he Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate

Change (UNFCCC or FCCC), an international environmental treaty produced at the United

Nations Conference on treaty is intended to achieve "stabilization of greenhouse gas

concentrations in the atmosphere at a level that would prevent dangerous anthropogenic

interference with the climate system."

T

The Kyoto Protocol establishes legally binding commitments for the reduction of four

greenhouse gases (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride), and two groups

of gases (hydrofluorocarbons and perfluorocarbons ) produced by "Annex I" (industrialized)

nations, as well as general commitments for all member countries. As of January 2009[update],

183 parties have ratified the protocol, which was initially adopted for use on 11 December 1997

in Kyoto, Japan and which entered into force on 16 February 2005. Under Kyoto, industrialized

countries agreed to reduce their collective GHG emissions by 5.2% compared to the year 1990.

National limitations range from 8% reductions for the European Union and some others to 7%

for the United States, 6% for Japan, and 0% for Russia. The treaty permitted GHG emission

increases of 8% for Australia and 10% for Iceland.

Countries with commitments under the Kyoto Protocol to limit or reduce greenhouse gas

emissions must meet their targets primarily through national measures. As an additional means

of meeting these targets, the Kyoto Protocol introduced three market-based mechanisms, thereby

creating what is now known as the “carbon market.”


The Kyoto mechanisms are:

1. Emissions Trading

2. The Clean Development Mechanism (CDM)

3. Joint Implementation (JI)

3.1 Emissions Trading

Emissions trading, as set out in Article 17 of the Kyoto Protocol, allows countries that have

emission units to spare - emissions permitted them but not "used" - to sell this excess capacity to

countries that are over their targets.

Since carbon dioxide is the principal greenhouse gas, people speak simply of trading in carbon.

Carbon is now tracked and traded like any other commodity. This is known as the "carbon

market."

3.2 The Clean Development Mechanism

The Clean Development Mechanism (CDM), defined in Article 12 of the Protocol, allows a

country with an emission-reduction or emission-limitation commitment under the Kyoto

Protocol to implement an emission-reduction project in developing countries. Such projects can

earn saleable certified emission reduction (CER) credits, each equivalent to one ton of CO2,

which can be counted towards meeting Kyoto targets.


The mechanism is seen by many as a trailblazer. It is the first global, environmental investment

and credit scheme of its kind, providing standardized emissions offset instrument, CERs.

A CDM project activity might involve, for example, a rural electrification project using solar

panels or the installation of more energy-efficient boilers. As WHRPP at M.L.C.F.L. is an

example of CDM certified project.

The mechanism stimulates sustainable development and emission reductions, while giving

industrialized countries some flexibility in how they meet their emission reduction or limitation

targets.

3.2.1 Operating details of the CDM

A CDM project must provide emission reductions that are additional to what would otherwise

have occurred. The projects must qualify through a rigorous and public registration and

issuance process. Approval is given by the Designated National Authorities. Public funding

for CDM project activities must not result in the diversion of official development assistance.

The mechanism is overseen by the CDM Executive Board, answerable ultimately to the

countries that have ratified the Kyoto Protocol.

Operational since the beginning of 2006, the mechanism has already registered more than

1,000 projects and is anticipated to produce CERs amounting to more than 2.7 billion tonnes

of CO2 equivalent in the first commitment period of the Kyoto Protocol, 2008–2012.

3.3 Joint Implementation (JI)

Joint implementation offers Parties a flexible and cost-efficient means of fulfilling a part of

their Kyoto commitments, while the host Party benefits from foreign investment and

technology transfer.


http://cdm.unfccc.int/EB/index.html

http://cdm.unfccc.int/DNA/index.html

3.3.1 Eligibility and approval

A JI project must provide a reduction in emissions by sources, or an enhancement of

removals by sinks, that is additional to what would otherwise have occurred. Projects must

have approval of the host Party and participants have to be authorized to participate by a

Party involved in the project.

Projects starting as from the year 2000 may be eligible as JI projects if they meet the

relevant requirements, but ERUs (emission reduction units) may only be issued for a

crediting period starting after the beginning of 2008.

3.3.2 Track 1 and Track 2 procedures

If a host Party meets all of the eligibility requirements to transfer and/or acquire ERUs, it

may verify emission reductions or enhancements of removals from a JI project as being

additional to any that would otherwise occur. Upon such verification, the host Party may

issue the appropriate quantity of ERUs. This procedure is commonly referred to as the

“Track 1” procedure.”

If a host Party does not meet all, but only a limited set of eligibility requirements,

verification of emission reductions or enhancements of removals as being additional has to

be done through the verification procedure under the Joint Implementation Supervisory

Committee (JISC). Under this so-called “Track 2” procedure, an independent entity

accredited by the JISC has to determine whether the relevant requirements have been met

before the host Party can issue and transfer ERUs.

A host Party which meets all the eligibility requirements may at any time choose to use the


http://ji.unfccc.int/Eligibility/index.html

verification procedure under the JISC (Track 2 procedure).

4

Waste Heataste heat is heat, which is generated in a process by way of fuel combustion or chemical

reaction, and then “dumped” into the environment even though it could still be reused for

some useful and economic purpose. The essential quality of heat is not the amount but rather its

“value”.

W

4.1 Benefits of Waste Heat Recovery

Benefits of ‘waste heat recovery’ can be broadly classified in two categories:

4.1.1 Direct Benefits

Recovery of waste heat has a direct effect on the efficiency of the process. This is reflected by

reduction in the utility consumption & costs, and process cost.

4.1.2 Indirect Benefits

a) Reduction in pollution: A number of toxic combustible wastes such as carbon monoxide gas, sour

gas, carbon black off gases, oil sludge, Acrylonitrile and other plastic chemicals etc, releasing to

atmosphere if/when burnt in the incinerators serves dual purpose i.e. recovers heat and reduces the

environmental pollution levels.


b) Reduction in equipment sizes: Waste heat recovery reduces the fuel consumption, which leads to

reduction in the flue gas produced. This results in reduction in equipment sizes of all flue gas

handling equipments such as fans, stacks, ducts, burners, etc.

c) Reduction in auxiliary energy consumption: Reduction in equipment sizes gives additional

benefits in the form of reduction in auxiliary energy consumption like electricity for fans, pumps etc.

5

Development of a Waste Heat Recovery

System

5.1 Steps in Waste Heat Recovery System Development

5.1.1 Understanding the Process

nderstanding the process is essential for development of Waste Heat Recovery system.

This can be accomplished by reviewing the process flow sheets, layout diagrams, piping

isometrics, electrical and instrumentation cable ducting etc. Detail review of these documents

will help in identifying:

U

a) Sources and uses of waste heat

b) Upset conditions occurring in the plant due to heat recovery

c) Availability of space

d) Any other constraint, such as dew point occurring in an equipments etc.


After identifying source of waste heat and the possible use of it, the next step is to select suitable

heat recovery system and equipments to recover and utilize the same.

5.1.2 Economic Evaluation of Waste Heat Recovery System

It is necessary to evaluate the selected waste heat recovery system on the basis of financial

analysis such as investment, depreciation, payback period, rate of return etc.

5.2 Gas Flow Diagram of Cement Plant

The following diagram shows gas flow in a dry cement kiln.


Fig-2 Gas Flow Diagram of Cement Plant

5.3 Gas Flow Diagram in Cement Plant and WHRPP

The following diagram shows a schematic of tie in of waste heat recovery power plant boilers

gas ducts with existing cement plant .


Fig-3 Gas Flow Diagram in Cement Plant and WHRPP

6Waste Heat Recovery in M.L.C.F.L.

Iskanderabad

Waste Heat Recovery in M.L.C.F.L. Iskanderabad will result in:


Environmental Development

• significant reduction in the emissions of Greenhouse Gases

• improvement of the local environment by reduction in temperature of the vented

hot air

• reduction in local air pollutants which will benefit the local community due to

reduced costs for health care and climate change adaptation

Social Development

• Creation of new permanent jobs during construction and operation phase of the

project activity

• Alleviation of poverty by providing labour employment opportunities to the local

community during construction phase

• Positive impact on local communities by avoiding grid electricity which will

become available for domestic consumers

Economic Development

• Cost effective way of generating electricity since no additional fuel is used

• Trigger new economic activities within the same sector of economy.

Technology Development

• Diffusion of the new technology in the industrial sector. This would provide

ample opportunity to local engineers and engineering companies to study this

technology and develop similar indigenous technologies which would reduce

future technology imports.


6.1 Waste and Effective Energy Comparison

The schematic shows that how much effective is Waste Heat Recovery. Out of 38% Waste heat

in Cement dry process 18% heat can be saved by installation of effective heat recovery

equipment.

Fig-4 Waste and Effective Energy Comparison

6.2 Building Blocks of WHRPP

The following two divisions are involved in waste heat recovery system:

6.2.1 Grey Cement Plant

6.2.2 Power Generation Plant


Fif-5 Simplified diagram of Power Flow

6.2.1 Grey Cement Plant

Process Description:

Waste gas discharged from the clinker cooler system, and the kiln pre-heater system all contain

useful energy that can be converted into power by installation of a waste heat boiler system that


runs a steam turbine system. This report focuses on the steam turbine system since these systems

have been installed in many plants worldwide and have proven to be economic

Heat recovery has limited application for plants with in-line raw mills, as the heat in the kiln

exhaust is used for raw material drying. So at each step in heat recovery system gases are re-

circulated to existing system after Waste heat recovery boilers.

Waste Heat Recovery Boilers will be installed between pre-heater and Raw Mill of Line-1 and

Line-2. This step will lead to an energy efficient process and clinker electricity (KWh) cost will

be reduced by 26% without using any extra fuel.

Line-1 (4000 tons per day of clinker Kiln)

Its production is 4000 tons per day of clinker. Waste gases, rejected from preheater and clinker

cooler, properties are as given below:

i. Preheater Heat Exchanger 1 (Line 1 Preheater)

Waste Gas characteristics are as given below:

Waste Gas to be recovered = 214,000 Nm^3 / hour

Gas Temperature = 330°C

Steam characteristics to be generated by waste gas are as given below:

Steam Generated = 15.4 t/h

Steam temperature = 312 °C

Steam Pressure = 1.63 MPa

ii. Clinker Cooler Heat Exchanger 1


Waste Gas to be recovered = 103,333 Nm^3 / hour


Gas Temperature = 380°C


Steam generated = 8.5 t/h



Line-2 (6700 tons per day of clinker Kiln)

Its production is 6700 tons per day of clinker. Waste gases, rejected from preheater and clinker

cooler, properties are as given below:

i. Preheater Heat Exchanger 2 (Two Boilers)

Line-2 is a state of art technology and its preheater is double string. So at each string

one boiler is installed and both are identical.


Waste Gas to be recovered =195,500x2 Nm^3 / hour

Gas Temperature =310°C


Steam Generated=23 t/h



ii. Clinker Cooler Heat Exchanger 2


Waste Gas to be recovered =173,000 Nm^3 / hour




Steam Generated=15.6 t/h



Installing Waste Heat Recovery Boilers at Line-1 and Line-2


Fig-6 Block Diagram of Waste Heat Recovery Power with Two Cement Lines

6.2.2 Power Generation Plant


2nd source of waste heat is the exhaust of Wartsila engine. This waste heat comprises only 11%

of total waste heat to be utilized by the project activity. Currently, all the waste heat from this

source is vented to atmosphere without any recycling.

Gas duct will be taken before stack of Wartsila Power Generator.

It can operate in two modes as follows:

I. Gas mode

Wartsila Power Generator mostly works in gas mode as it is economical and gas is available

almost whole year.





Steam Generated= 7.9t/h




II. Diesel Mode

Wartsila rarely works in Diesel mode as diesel expensive.





Steam Generated= 6.1t/h




6.2.3 Block Diagram with Wartsila and GCD

Fig-7 Block Diagram of Waste Heat Recovery Power Plant with Two Cement Lines and Wartsila


6.2.4 Technical specifications of Heat Recovery units

EQUPMENT LOCATION WASTE GAS Nm^3/Hr

Steam Capacity

TPH

Steam Pressure

MPa

Steam Temperature

°C

HRSG 1 Preheater line 1

214000 15.4 1.63 312

HRSG 2 Clinker cooler Line1

103333 8.5 1.63 355


195500 11.5 1.63 301


195500 11.5 1.63 301

HRSG 5 Clinker cooler Line2

173000 15.6 1.63 366

HRSG 6 Exhaust of Wartsila

80912 7.9 1.68 370

Table-1 Technical specifications of Heat Recovery units


7

Power Output

he total system output power will be 13.9MW. This power will be utilized according to

load flow schemes arranged. T7.1 Inputs Proportion of each System to Waste Heat Recovery Plant

Now let us calculate Proportion of each input to Waste Heat Recovery System.

Fig-8 Inputs to Waste Heat Recovery Power Plant


7.1.1 Percentage of Line-1

I/p %age of Line-1= (Steam generated by Line 1)*100 / (Total Steam Generated)

I/p %age of Line-1 = 23.9*100/70.4

I/p %age of Line-1 = 34%

Electricity Proportion = 5MW

7.1.2 Percentage of Line-2

I/p %age of Line-2= (Steam generated by Line-2)*100 / (Total Steam Generated)

I/p %age of Line-2 = 38.6*100/70.4

I/p %age of Line-2 = 55%

Electricity Proportion = 7.9MW

7.1.3 Percentage of Wartsila

I/p %age of Wartsila= (Steam generated by Line-2)*100 / (Total Steam Generated)

I/p %age of Wartsila = (6.1~7.9)*100/70.4

I/p %age of Wartsila = (8~11) %

Percentage of Wartsila varies from 8% to 11% as it switches from Diesel to Gas mode.

Electricity Proportion = 1MW


Fig-9 Complete Block Diagram of Waste Heat Recovery Power Plant with Two Cement Lines and Wartsila Electric Generator

7.2 Power Flow Diagram of Waste Heat Recovery Power Plant System

The power flow diagram describes how power flows from Waste gases to generator total output

power is 13.9MW.

Fig-10 Power Flow Diagram of Waste Heat Recovery Power Plant System


8Health Safety and Environment

HRPP team is committed to operational excellence. This steadfast commitment is founded

on our respect for social and environmental issues, a core value that effectively and

efficiently drives achievement of our project.

W8.1 Beliefs:

Occupational injuries and illnesses are preventable.

Source reduction/elimination is the best waste management practice. Alternatives to

source reduction/elimination will focus on reuse, recycling and waste minimization.

8.2 Principles:

People are our most important resource, and as such, safety is our number one (#1)

core value. We must constantly strive to achieve zero (0) injuries and illnesses.

We are all accountable for ourselves and the safety of others in the workplace.

Working safely is a condition of employment.

Our efforts must be focused on prevention of occupational injury and illness;

therefore, we will provide requisite training to our employees to empower our

incident prevention culture.

Whole team, contractors and subcontractors are accountable for performing their

daily activities in a manner consistent with our HSE policy.

When an injury or serious incident occurs, we will thoroughly and completely

determine its cause and share the lessons learned.

We will strive to preserve the environment in which we operate by utilizing

resources responsibly and by reducing and eliminating waste from our operations at

the source; however, where wastes are generated, they will be handled safely and

responsibly.

Our work will be conducted in an atmosphere of trust, openness and cooperation.


waste heat recovery in cement industry at mapl leaf cement factory

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