This document discusses the use of condensing economizers for recovering waste heat from exhaust gases. It describes how condensing economizers can recover both sensible and latent heat from exhaust gases, increasing fuel utilization efficiency up to 95%. Case studies show their effectiveness in recovering waste heat from boilers and other heat sources in industrial processes like paper mills. Condensing economizers indirectly transfer waste heat to heat sinks via countercurrent heat exchange, preheating process fluids and reducing fuel consumption.
Generation of Air Conditioning by using Exhaust Gases and Cooling Water of an...ijtsrd
Air conditioning system of car or buses works on principle of vapor absorption cycle of refrigeration VAR . This system reduces the fuel economy of fuel of vehicle. When vehicle moving with air conditioning, it consumes more amount of fuel than vehicle rubs without AC, typically, it consumes 15 to 20 more amount of fuel. Exhaust gases coming from engine of vehicle have temperature ranges to 300 to 400 degree centigrade at full load it carries 25 to 30 of heat supplied by fuel. For A.C. of an automobile, the heat of exhaust gases is utilized to run vapor absorption refrigeration cycle instead of vapour compression refrigeration system. Resulting, it improves fuel economy of A. C. heavy vehicle. In this project try to integrate the vapor absorption refrigeration system with car or bus or heavy vehicle engine exhaust. Comparative study has been carried out when car running with VCR and vapor absorption system of refrigeration. Dr. M. Sampath Kumar | Karthik Payam | Rajesh Medi | Srikanth Chennam | Aditya Mothukuri ""Generation of Air Conditioning by using Exhaust Gases and Cooling Water of an Automobile Engine"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23318.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23318/generation-of-air-conditioning-by-using-exhaust-gases-and-cooling-water-of-an-automobile-engine/dr-m-sampath-kumar
Thermo Tech Engineering (TTE) is involved in manufacturing of industrial utility equipments and general fabrication. We offer complete waste heat recovery equipment Custom design fabrication installation and commissioning.
Thermo Tech Engineering (TTE) is involved in manufacturing of industrial utility equipments and general fabrication. We offer complete waste heat recovery equipment Custom design fabrication installation and commissioning.
Generation of Air Conditioning by using Exhaust Gases and Cooling Water of an...ijtsrd
Air conditioning system of car or buses works on principle of vapor absorption cycle of refrigeration VAR . This system reduces the fuel economy of fuel of vehicle. When vehicle moving with air conditioning, it consumes more amount of fuel than vehicle rubs without AC, typically, it consumes 15 to 20 more amount of fuel. Exhaust gases coming from engine of vehicle have temperature ranges to 300 to 400 degree centigrade at full load it carries 25 to 30 of heat supplied by fuel. For A.C. of an automobile, the heat of exhaust gases is utilized to run vapor absorption refrigeration cycle instead of vapour compression refrigeration system. Resulting, it improves fuel economy of A. C. heavy vehicle. In this project try to integrate the vapor absorption refrigeration system with car or bus or heavy vehicle engine exhaust. Comparative study has been carried out when car running with VCR and vapor absorption system of refrigeration. Dr. M. Sampath Kumar | Karthik Payam | Rajesh Medi | Srikanth Chennam | Aditya Mothukuri ""Generation of Air Conditioning by using Exhaust Gases and Cooling Water of an Automobile Engine"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23318.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23318/generation-of-air-conditioning-by-using-exhaust-gases-and-cooling-water-of-an-automobile-engine/dr-m-sampath-kumar
Thermo Tech Engineering (TTE) is involved in manufacturing of industrial utility equipments and general fabrication. We offer complete waste heat recovery equipment Custom design fabrication installation and commissioning.
Thermo Tech Engineering (TTE) is involved in manufacturing of industrial utility equipments and general fabrication. We offer complete waste heat recovery equipment Custom design fabrication installation and commissioning.
Energy Efficiency Potential in Food & Beverage Industries in Nepaleecfncci
This presentation provides detailed information about energy saving opportunties in food and beverage sector in Nepal. The status of various subsectors is shown and major energy saving opportunties are explained. The findings are based on a GIZ baseline study conducted in 200 industries in 2012.
With a properly applied condensing heat recovery system, thermal efficiencies nearing 100% can be achieved. Even if your site is unable to achieve this level of efficiency, improvements in energy efficiency can be realized through condensing heat recovery. Typically, 5 to 20 percent fuel savings can be practically and economically realized. Given all that, it makes sense to learn more about condensing heat recovery technologies.
An Introduction to Air to water, Air Source, Heat Pump SystemsSpaceAir
Space Air is delighted to provide an overview of its latest RIBA accessed CPD seminar. Covering the basic principles and systems available. Developed by people with years
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
Syllabus:
Availability and Irreversibility
Availability Function
Second Law Efficiencies
Work Potential Associated with Internal Energy
Waste Heat Recovery
Heat Losses – Quality vs. Quantity
Principle of Heat Recovery Units
Classification of WHRS on Temperature Range Bases
Commercial Viable Waste Heat Recovery Devices
Benefits of Waste Heat Recovery
Development of a Waste Heat Recovery System
Commercial Waste Heat Recovery Devices
West Heat Recovery Boiler (WHRB)
Recuperators- Regenerative, Ceramic, Regenerative Heat Exchanger
Thermal wheel/ Heat Wheel
Heat Pipe
Economiser
Feed Water
Heat Pump
Shell and Tube Heat Exchanger
Plate Heat Exchanger
Run-around coil
Direct Contact Heat Exchanger
Advantages and Limitations of WHRD’s
Energy Efficiency Potential in Food & Beverage Industries in Nepaleecfncci
This presentation provides detailed information about energy saving opportunties in food and beverage sector in Nepal. The status of various subsectors is shown and major energy saving opportunties are explained. The findings are based on a GIZ baseline study conducted in 200 industries in 2012.
With a properly applied condensing heat recovery system, thermal efficiencies nearing 100% can be achieved. Even if your site is unable to achieve this level of efficiency, improvements in energy efficiency can be realized through condensing heat recovery. Typically, 5 to 20 percent fuel savings can be practically and economically realized. Given all that, it makes sense to learn more about condensing heat recovery technologies.
An Introduction to Air to water, Air Source, Heat Pump SystemsSpaceAir
Space Air is delighted to provide an overview of its latest RIBA accessed CPD seminar. Covering the basic principles and systems available. Developed by people with years
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
Syllabus:
Availability and Irreversibility
Availability Function
Second Law Efficiencies
Work Potential Associated with Internal Energy
Waste Heat Recovery
Heat Losses – Quality vs. Quantity
Principle of Heat Recovery Units
Classification of WHRS on Temperature Range Bases
Commercial Viable Waste Heat Recovery Devices
Benefits of Waste Heat Recovery
Development of a Waste Heat Recovery System
Commercial Waste Heat Recovery Devices
West Heat Recovery Boiler (WHRB)
Recuperators- Regenerative, Ceramic, Regenerative Heat Exchanger
Thermal wheel/ Heat Wheel
Heat Pipe
Economiser
Feed Water
Heat Pump
Shell and Tube Heat Exchanger
Plate Heat Exchanger
Run-around coil
Direct Contact Heat Exchanger
Advantages and Limitations of WHRD’s
”Waste heat recovery” is the process of “heat integration”, that is, reusing heat energy that would otherwise be disposed of or simply released into the atmosphere. By recovering waste heat, plants can reduce energy costs and CO2 emissions, while simultaneously increasing energy efficiency.
Waste heat recovery, co geration and tri-generationAmol Kokare
Diploma in Mechanical Engg.
Babasaheb Phadtare Polytechnic, kalamb-walchandnagar
Sub- Power plant engineering
Unit-Waste heat recovery, co geration and tri-generation.
By- Prof. Kokare Amol Yashwant
Classification, Advantages and applications, Commercially viable
waste heat recovery devices, Saving potential.
Waste 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”. The strategy of how to recover this heat depends in part on the temperature of the waste
heat gases and the economics involved.
WASTE HEAT RECOVERY TO INCREASE BOILER EFFICIENCY USING BAGASSE AS FUEL IAEME Publication
Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Waste heat found in the
exhaust gas can be used to preheat the incoming gas. This is one of the basic methods for recovery of waste heat. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
a). EconomiserAn economiser is a mechanical device which is used a.pdfrajat630669
a). Economiser
An economiser is a mechanical device which is used as a heat exchanger by preheating a fluid to
reduce energy consumption. In a steam boiler, it is a heat ex-changer device that heats up fluids
or recovers residual heat from the combustion product i.e. flue gases in thermal power plant
before being released through the chimney. Flue gases are the combustion exhaust gases
produced at power plants consist of mostly nitrogen, carbon dioxide, water vapor, soot carbon
monoxide etc. Hence, the economiser in thermal power plants, is used to economise the process
of electrical power generation, as the name of the device is suggestive of. The recovered heat is
in turn used to preheat the boiler feed water, that will eventually be converted to super-heated
steam. Thus, saving on fuel consumption and economising the process to a large extent, as we
are essentially gathering the waste heat and applying it to, where it is required. Nowadays
however, in addition to that, the heat available in the exhaust flue gases can be economically
recovered using air pre-heater which are essential in all pulverized coal fired boiler.
b). Reheater
ins some heat either from the combustion gases leaving the boiler (if there is still much
temperature difference) or by adding more heat by burning small amount of fuel. The energy of
the exhaust steam with the gained heat increases the steam enthalpy of the steam and give a good
opportunity to generate much work with the low pressure turbine. The two works (High pressure
W_H and Low pressure W_L) are much greater than the heat added by fuel burned (Q1 and Q2),
so the efficiency increases. Another issue, the reheat helps in saving the turbine blades from
corrosion due to low dryness fraction x<0.88 which it may occur if one single stage turbine is
used.
c). Cogeneration
Cogeneration (Combined Heat and Power or CHP) is the simultaneous production of electricity
and heat, both of which are used. The central and most fundamental principle of cogeneration is
that, in order to maximise the many benefits that arise from it, systems should be based on the
heat demand of the application. This can be an individual building, an industrial factory or a
town/city served by district heat/cooling. Through the utilisation of the heat, the efficiency of a
cogeneration plant can reach 90% or more.
Cogeneration therefore offers energy savings ranging between 15-40% when compared against
the supply of electricity and heat from conventional power stations and boilers.
Cogeneration optimises the energy supply to all types of consumers, with the followingbenefits
for both users and society at large:
d). Turbocharging
A turbocharger, or turbo (colloquialism), from Greek \"\" (\"wake\"),[1] (also from Latin
\"turbo\" (\"spinning top\"),[2]) is aturbine-driven forced induction device that increases an
internal combustion engine\'s efficiency and power output by forcing extra air into the
combustion chamber.[3][4] This improvement over a.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
1. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
CASE STUDY
USE OF CONDENSING ECONOMIZERS FOR ENERGY RECOVERY FROM
EXHAUST GASES
Introduction
In most industrial or commercial heating processes, a large amount of the heat energy that is produced
through fuel combustion is underutilized and wasted in the exhaust gas streams. For boilers, turbines
and dryers the typical fuel utilization efficiency is 80% (plus or minus 5%). Wasting 20% of the fuel that
is fired is inefficient and extremely costly. It is also unnecessary. Very large quantities of this unused
energy are recoverable and reusable. Now, even the portions of this unused energy that were previously
thought to be unrecoverable can now be returned for beneficial use. The method now gaining wide
spread use for recovery of this energy is called a Condensing Economizer.
Throughout the industrial, institutional and commercial heating sectors there are exhaust gas sources
that contain both high grade and low grade heat energy. Both types of heat are valuable and can be
reused. Figure 1 shows the vast quantities of heat energy that is currently being wasted, broken down
by industry sector and shaded to show the breakdown between high and low grade heat. In some
industrial sectors as much as 74% of the heat input energy is wasted in exhaust gas.
% Purchased Fuel Lost As Waste Heat
Figure 1
Paper Chemicals Petroleum Non-metallic Metals
With such large amounts of input energy being wasted, it is easy to understand why the United States
Department of Energy has identified waste heat recovery as the single largest opportunity in the pursuit
of improved energy efficiency.
2. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
As the graph in Figure 2 illustrates, the possible savings through increased rates of heat recovery are
more than double those related to other efficiency measures. With such large losses, and the availability
of proven methods to recover and reuse this energy, the economic and emission reduction opportunities
through heat recovery are readily apparent and exciting. There are many heat recovery methods
available and utilized by industrial and institutional heat sources; however Condensing Economizers are
widely recognized as the most effective method of heat recovery.
0
400
800
1200
1600
2000
Possiblesavingsbyapplication
(TeraBTUs/year)
Figure 2
Condensing Economizers
For most heat sources – boilers, dryers, ovens, etc., there is component of waste or underutilized energy,
energy that is consumed but not utilized. This is often the case due to a functional disconnect between
the processes being served by the thermal energy being produced and the availability of the energy still
remaining the exhaust gas. For example, a boiler that is delivering steam to serve several industrial
processes would traditionally have been designed to provide all of the plant heating requirements from
steam. Now, by recovering heat from the boiler exhaust gas it is feasible to take the heating duty of one
of the processes and provide that heating duty from recovered waste heat, rather than steam. By
reducing the steam consumption, the amount of fuel required by the boilers is reduced which creates a
dollar savings incentive and a commensurate reduction in emissions is also achieved. Boiler make up
water is an easy example: when a process loses steam (direct injection, blowdown, etc.) the boiler plant
must make up for this lost water by adding in fresh water. Traditionally this water would be added to the
deaerator cold, or blended in with condensate return. By pre-heating this make up water using the
energy in the exhaust gas, less fuel will be used in the boiler to heat the cold water and a savings is
created.
3. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
When a flue gas contains moisture, which all hydrogen based fuel exhausts do, the heat available for
recovery from the is of two types: sensible and latent heat. During the combustion process of hydrogen
based fuels such as natural gas, the hydrogen in the fuel is combined chemically with the oxygen in the
combustion air, this creates water which is instantly vaporized and adds water vapor content to the
exhaust gas. The energy consumed by the vaporization of this water is called the “latent heat of
vaporization”. The vaporization process consumes approximately 17% of the input energy by volume.
And this energy cannot be recovered without extracting enough energy from the flue gas to cool it to
below the water vapor dew point. A condensing economizer system can complete this task of recovering
the latent energy and will also recover the sensible heat energy above the water vapor dew point as well.
Figure 3, below, illustrates the increased rate of heat transfer and efficiency increase once the heat
recovery process enters the latent recovery zone. The red portion of the heat transfer curve represents
the sensible heat transfer rate as it relates to the exit flue gas temperature. The blue portion of the
curve represents the sensible and latent heat transfer rate. The heat transfer rate increases
exponentially once the heat transfer includes latent heat energy recovery. Also illustrated is the increase
in over all fuel utilization efficiency. The pink dotted line illustrates that when a flue gas is cooled to
105 o
F and the recovered energy is reutilized, the resulting operating efficiency of the fired equipment
(boilers, etc.) is increased to 95%. A normal exit flue gas temperature of 450o
F represents an operating
efficiency of 80%, so a 15% increase in fuel efficiency is a substantial gain!
Figure 3
4. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
A condensing economizer gathers the waste heat from singular or multiple heat sources and transfers the
wasted heat energy to a heat sink in the plant that would otherwise consume purchased or live energy to
provide the heating duty. By utilizing waste heat for this purpose, less fuel consumption is required and
an overall fuel cost savings and emission reduction target is achieved.
Traditional heat recovery methods limited their heat recovery and avoided by a wide margin cooling the
flue gases to the water vapor dew point. This was done in order to avoid the corrosive effects that the
flue gas condensate will create. Advancements in metallurgy and heat recovery methodology now allow
for this energy to be recovered and the fuel cost savings realized. The ConDex Condensing Economizer
System was one of the earliest fully condensing economizer systems to attain commercial viability in the
market through rigorous testing and successful field applications which have led to wide spread
acceptance for reliability and durability.
Figure 4
By heating cold process fluids such as boiler make up water, process water, etc. the ConDex system can
recover both sensible and latent heat and put it to substantive work that would otherwise require the use
of purchased energy. The image in Figure 4 above summarizes how the ConDex system recovers and
transfers the waste heat energy. The system uses counter current heat transfer flow, where incoming
fluid enters the exchanger at the bottom and is heated as it travels upwards against the hotter flue
gases. Because some of the tubes in the exchanger are below the water vapor dew point temperature,
the flue gas water vapor begins to condense and latent heat is recaptured in addition to the sensible
heat. The tubes keep the water being heated separate from the flue gas which avoids contamination of
the water. The indirect contact aspect also allows the system to recover greater amounts of heat and
heat the water to higher temperature than the direct contact, spray tower type of flue gas heat recovery
system.
The system uses a fan to convey the flue gas away from its normal pathway out of the existing stack
which protects it against the colder flue gas and allows for the flue gas condensate water to be collected
for potential reuse.
5. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
Condensing economizers can be used in a wide variety of industrial and institutional applications and heat
sources. Below in Figure 5 the diagram shows a typical ConDex condensing economizer system set up
for recovering latent heat from a package boiler. The same schematic applies to single or multiple
boilers. For multiple boiler (or other heat sources) applications a single ConDex unit will tie into all of the
boiler stacks, combine the flue gas flows and recycle the heat into the process fluid or heating loop that
requires heat.
Figure 5
Case Studies for Use of Condensing Economizer Systems
Graphic Packaging International Inc. Paperboard Mill in Santa Clara, California Runs
Greener with Natural Gas saving Condensing Economizer
For more than 50 years, making coated-recycled paperboard has been the daily routine at Graphic
Packaging’s paper mill, located in Santa Clara, California. Using 100% recycled fiber as raw material, the
paper mill presently manufactures more than 380 tons of clay-coated paperboard daily for high-end
consumer packaging customers of Graphic Packaging International, Inc., a subsidiary of Graphic
Packaging Holding Company. Now the mill manufactures the paperboard using several million therms less
natural gas thanks to a new ConDex Condensing Economizer waste heat recovery system.
The Santa Clara mill uses a 25 megawatt combined cycle gas turbine to generate electricity for the plant.
The turbine also has an integrated heat recovery steam generator (HRSG) that captures the initial waste
heat from the turbine to generate steam for the mill operational requirements. In order to maintain the
steam output from the HRSG at required levels, the turbine uses duct burners after the turbine to re-heat
6. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
the flue gas which allows for a more precise level of control of the steam output, while not affecting the
electrical generation capacity of the turbine.
Graphic Packaging recognized that there was considerable heat (thermal) energy being exhausted out of
the turbine stack and approached ConDex Condensing Economizers about exploring the potential
recovery and reuse opportunities for this wasted energy. The initial phases of the investigation centered
around finding plant processes that were using steam to heat liquids that could otherwise be heated with
recovered energy from the turbine exhaust. The plant personnel forwarded the idea to investigate using
the recovered energy to heat the mill paper machine water. The investigation revealed that the mill
water was consuming approximately 25,000 lb/hr of live steam energy to maintain the required
temperature of the water. A recovery balance investigation by ConDex confirmed that the turbine flue
gas contained enough energy to fulfill this heat requirement and create a substantial savings opportunity.
By using the recovered energy to heat the water, less steam output would be required from the HRSG.
This would allow the plant to turn down the fuel input to the duct burners, as less energy would be
required in that section and create the opportunity for substantial fuel expenditure savings as well as a
significant associated emissions reduction (CO2, NOx,). By pre-heating the mill water, less steam would
be required from the steam generator which would allow the plant to turn down the amount of fuel sent
to the duct burners which would in turn generate a substantial fuel expenditure savings. This is what the
plant decided to do.
In addition to heating the paper mill water, the investigation also revealed that additional savings
opportunities were available by heating the HRSG make up water. Instead of sending steam to the
deaerator to heat the incoming cold fresh water, recovered energy, even after the mill water heating
section, was available for this process as well. The plant decided to immediately undertake the heat
recovery for the mill water and contracted ConDex to design the system.
Figure 6 Figure 7
The ConDex condensing economizer is a stand-alone heat recovery system that attached to the existing
turbine/HRSG exhaust stack. As shown in Figures 6 & 7 above, the ConDex system uses a large fan to
pull the flue gases away from its current pathway up the existing stack and sends the hot gases to the
Condex exchanger to recover and transfer heat to the cold process water.
7. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
The paper machine water plays an important role in the paper making process and has a direct effect on
the speed that the paper machine can operate at. By maintaining the water temperature at higher
temperatures the machine can operate faster and produce more paper in less time. In order to maintain
the temperature, the water is sent to the condensing heat recovery system from the coldest section, and
looped back to maintain the target. This sends the coldest water to the heat recovery system. Because
the temperature of the water is below the water vapor dew point of the turbine exhaust gas, the water
vapor condenses and turns back to a liquid state and releases the latent heat of vaporization and
transfers it to the process water. This requires that the system be comprised of robust metallurgy in
order to withstand the flue gas condensate which becomes mildly acidic due to the absorption of CO2
from the flue gas.
Water Recovery
For every pound of natural gas combusted 2.25 pounds of water vapor is produced. This not only
represents a significant amount of latent heat energy, but a significant amount of water that can also be
recovered. Graphic Packaging is recovering 2.7 gallons per minute of water from the flue gas that would
otherwise be lost to atmosphere. This water is recoverable and reusable post treatment for a variety of
purposes. In many cases it is used also to blend with and neutralize steam generation blow down.
Figure 9 shows a picture of the flue gas condensate water in its collection basin. As water is also a
valuable resource, this is often a very important secondary benefit of condensing heat reclamation.
Figure 8 Figure 9
System Control
The Condensing heat recovery system uses a variable speed drive on the fan that conveys the waste flue
gas. Depending on the amount of heat required to heat the process fluid, the fan speed modulates
accordingly. This maintains a balance between the availability of waste heat and the heat sink
requirements. In order to maintain safe operation and offer zero impact on the operation of the turbine,
there is also a fail-closed damper between the condensing economizer fan and the turbine exhaust stack.
This damper can also modulate to allow greater or reduced flow rates of exhaust gas.
8. Combustion & Energy Systems, Ltd.
Documents are to be considered Private and Confidential and are not to be copied or transferred/released without an written consent from Combustion & Energy Systems Ltd.
System Performance
The ConDex condensing heat recovery system recovers over 25,000,000 Btu/hr at average load and
heats 1,300 GPM of water up to 180 F. The flue gas is cooled from 405 o
F down to 120 o
F, which
represents a substantial improvement in the plant fuel utilization efficiency, from approximately 81% up
to a much improved 92%.
The Santa Clara Graphic Packaging plant as well as the entire Graphic Packaging organization were
pleased with the overall results achieved by installing the condensing economizer system:
David W. Scheible, president and CEO of Graphic Packaging International, Inc. Said: “By adding state-of-
the-art heat exchange and recovery technology to its cogeneration power plant, the paper mill can now
capture and recycle valuable waste heat energy from the exhaust gases to reduce significantly the
volume of natural gas required by the power plant to heat process water essential to paperboard
production. Duct burner consumption of natural gas has been cut by 50 percent, eliminating more than
15,700 tons of CO2 emissions annually, equivalent to removing 2,198 cars per year off the road or saving
enough natural gas to annually heat over 5,000 homes.
“Every step to use energy more efficiently - like installing heat recovery technology to reduce natural gas
demand at our Santa Clara mill - improves the environment and sustains important energy resources like
natural gas. Starting in our workplace and in our communities, we must carefully examine what we do
and find new ways to increase our energy efficiency by at least ten percent. This will make a difference in
controlling energy costs, improving the U.S. economy and reducing greenhouse gas emissions – those
are good outcomes for all of us,”
Additional information on the ConDex condensing economizer project at Graphic Packaging can be
obtained at www.condexenergy.com