Oxy-fuel Combustion

Fundamentals, Theory and Practice

Chuguang Zheng, Zhaohui Liu

• Publisher: Academic Press
• Year: 2017
• Print ISBN: 9780128121450
• eBook ISBN: 9780128123225
• Topic: Physical Sciences
• Subtopic: Industrial & Technical Chemistry

Oxy-fuel Combustion: Fundamentals, Theory and Practice provides a comprehensive review of various aspects of oxy-fuel combustion technology, including its concept, fundamental theory, pilot practice, large-scale feasibility studies and related practical issues, such as the commissioning and operation of an oxy-fuel combustion plant. Oxy-fuel combustion, as the most practical large-scale carbon capture power generation technology, has attracted significant attention in the past two decades. As significant progress has been achieved in worldwide demonstration and the oxy-combustion concept confirmed by Schwartze Pump, CUIDEN, Callide, Ponferrada and Yingcheng projects in the past five years, this book provides a timely addition for discussion and study.- Covers oxy-fuel combustion technology- Includes concepts, fundamentals, pilots and large-scale feasibility studies- Considers related practical issues, such as the commissioning and operation of an oxy-fuel combustion plant- Focuses on theories and methods closely related to engineering practice

Chapter 1

Opportunities and Challenges of Oxy-fuel Combustion

Xiaohong Huang; Junjun Guo; Zhaohui Liu; Chuguang Zheng Huazhong University of Science and Technology, Wuhan, China

Abstract

This chapter briefly reviews the background, concept, components, R&D history, and opportunities related to the use of oxy-fuel combustion and then discusses the theoretical and practical challenges of oxy-fuel combustion. An outline for subsequent chapters is also provided.

Keywords

Oxy-fuel combustion; Opportunities; Challenges

1.1 Climate Change and Carbon Capture Storage

1.1.1 Carbon Emission and Climate Change

Greenhouse gases actually guarantee life by preventing heat from escaping the Earths atmosphere. Without this greenhouse effect, the Earth would be very cold. On the other hand, too big an increase in the greenhouse effect causes too much heat to be captured and may result in the Earth being unsuitable for human, plant, and animal life.

CO₂ is the most significant component of greenhouse gases. In addition to the carbon released naturally into the Earths ecosystem, humans emit a significant amount of carbon through activities such as burning fossil fuels, wood, and other biofuels. Moreover, human activities release carbon more effectively and rapidly into the atmosphere than natural sources do, thus increasing the atmospheric CO₂ concentration. In fact, the atmospheric CO₂ concentration is higher now than at any time during the past 500,000 years or longer.

Fig. 1.1 shows the atmospheric CO₂ levels at 400,000 years [1]. This data was based on the comparison of atmospheric samples contained in ice cores from Greenland and Antarctica and more recent direct measurements. It is significant that the atmospheric CO₂ level fluctuated regularly over the past 400,000 years but that the amount of CO₂ dramatically increased to >300 ppm in just the past few decades. This figure provides evidence-based proof that the Industrial Revolution led to a dramatic increase in atmospheric CO₂ levels.

Fig. 1.1 The atmospheric CO₂ levels for 400,000 years.

Fig. 1.2 presents the global CO₂ emissions in the past 250 years [2,3] and shows that global CO₂ emissions significantly increased during the past 100 years. The increasing trend almost looks like an exponential curve. To facilitate assessments of long-term trends of atmospheric global temperature, climatologists from NASA's Goddard Institute of Space Studies (GISS) compared the mean for a base period with the annual mean [4]. The temperature anomaly was used to indicate the change in global temperatures, which is defined as the difference between the baseline mean and the annual mean.

Fig. 1.2 The global carbon emissions in the 1751 to 2015 period.

Fig. 1.3 shows the global temperature anomalies between 1880 and 2015 from the Land Meteorological station [5]. In this figure, the period from 1951 to 1980 is used for the baseline period. It is shown that the temperature anomalies were consistently negative during the 1880–1935 period. In contrast, the anomalies have been consistently positive since 1980. The global temperature has increased continuously. Within the past 120 years, the most recent years show the highest anomalies of +0.8°C.

Fig. 1.3 The global annual temperature anomalies in the 1880–2015 period.

The climate of the Earth has varied throughout its history, sometimes considerably. Although the warming before 1950 was natural, it has shown that the processes of human-inspired industrialization are the main reasons for recent significant climate warming.

1.1.2 Status of CCS

Like efficiency improvements and low-carbon fuels, carbon capture and storage (CCS) is considered as a potential technology for achieving large-scale reduction of CO₂ emissions from fossil fuel-fired power generation. CCS comprises three stages: CO₂ capture, CO₂ transport, and CO₂ storage.

The aim of CO₂ capture technology is to provide high-concentration, high-pressure CO₂ sources from large point sources such as power plants. Captured CO₂ must be compressed and transported to suitable storage sites. Using pipelines to pump CO₂ is the cheapest transport method, and it is already a well-known and reliable technology. The purpose of CO₂ storage is to store the captured CO₂ and prevent it from entering the atmosphere. There are three options for geological CO₂ storage: saline formations, oil and gas reservoirs, and deep unmineable coal seams [6].

The technologies for each stage of the full CCS chain have different degrees of maturity, each CCS stage is technically available and has been used for many years.

CO₂ capture technologies have long been used in industry to remove CO₂ from gas streams where its not desired or to separate it as a product gas. Some of the earliest CCS projects were in natural gas processing, such as the Sleipner CO₂ storage project in Norway, which captures approximately one million tons of CO₂ per year.

CO₂ transport technology has been used safely for the past 30 years. Thousands of miles of CO₂ pipelines that transport CO₂ deal with naturally occurring CO₂ for enhanced oil recovery (EOR) in the United States. However, challenges exist in the systems that transport CO₂ from industrial power plants, because the amount of impurities in the CO₂ stream captured from the plants will influence the calculations for the hydraulic design of these pipelines.

Geologic CO₂ storage has been carried out for >10 years. Early projects injected CO₂ into different geologic formations, including saline formations and oil and gas reservoirs. Monitoring data has shown that the CO₂ performed as expected after storage. However, more investigation is needed to improve the predictions of CO₂ behavior and to evaluate possible storage sites, because each site will have unique circumstances. The deep saline formations are expected to provide long-term CO₂ storage solutions.

Currently, there are five commercial-scale CCS projects worldwide. The CO₂ streams of the Sleipner, Snøhvit (Norway), and In Salah (Algeria) projects all come from extracted natural gas, which contains a high concentration of CO₂. The CO₂ is separated, captured, and stored in underground geological formations. The Rangely project in North America uses CO₂ from natural gas processing for EOR and storage at the Rangely field in Colorado. At Weyburn-Midale, the CO₂ is captured from a coal-based synfuel plant in North Dakota and piped to an oil field in Canada. In total, five projects store over 5 Mt. of CO₂ per year.

In addition to using CO₂ for EOR, other CCS paths are not financially feasible. CCS reduces efficiency and adds cost. Thus commercial power plants and industrial facilities will not invest in CCS in the current regulatory and fiscal environment. Only when the costs are reduced will CCS be seen as viable in coal combustion [7]. Meanwhile, the driving force behind CCS research and development is mainly government funding.

Validation of the full CCS process is very expensive. However, the only way to solve the problem of integration and scale-up is to build and operate commercial-scale CCS facilities. In the past year, governmental and demonstration activities increased dramatically. Most of the major economies have already invested in large-scale CCS demonstration projects. For example:

● Australia committed AUD 100 million per year for 3 years for the formation of the Global CCS Institute (GCCSI) to foster international collaboration and announced AUD 2 billion for large-scale demonstration.

● Canada announced financial support of CAD 3.3 billion for research and development, mapping, and large-scale CCS project demonstration.

● The European Union (EU) allocated EUR 1.05 billion from an economic recovery energy program for the support of seven CCS demonstrations.

● Norway continues to play a leading role in the development of the Mongstad and Karstø projects.

● The United Arab Emirates is developing three large-scale CCS projects, building on the EOR area.

● The United Kingdom annou...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Preface
• Chapter 1: Opportunities and Challenges of Oxy-fuel Combustion
• Chapter 2: Fundamentals of Oxy-fuel Combustion
• Chapter 3: Coal Ignition in Oxy-fuel Combustion Environment
• Chapter 4: Pulverized Coal Combustion Characteristics in Oxy-fuel Atmospheres
• Chapter 5: Nitrogen and Sulfur Behavior During Oxy-fuel Combustion and Its Retention
• Chapter 6: Mineral Behavior During Oxy-fuel Combustion
• Chapter 7: Mercury Behavior and Retention in Oxy-fuel Combustion
• Chapter 8: Flame Characteristics of Oxy-fuel Combustion and Burner Design
• Chapter 9: Heat Transfer During Oxy-fuel Combustion and Boiler Design
• Chapter 10: Pilot and Industrial Demonstration of Oxy-fuel Combustion
• Chapter 11: System Integration and Optimization for Large Scale Oxy-fuel Combustion Systems
• Chapter 12: Control Concepts, Dynamic Behavior and Mode Transition Strategy for Oxy-fuel Combustion Systems
• Chapter 13: Oxygen Production for Oxy-fuel Combustion
• Chapter 14: MILD Oxy-fuel Combustion
• Chapter 15: Oxy-Steam Combustion
• Chapter 16: Chemical Looping Combustion
• Index