Sustainable Management of Coal Preparation

Dilip Kumar, Deepak Kumar

• Éditeur: Woodhead Publishing
• Année: 2018
• ISBN:
  9780128126356
• Sujet: Naturwissenschaften
• Sous-sujet: Energie

Sustainable Management of Coal Preparation explains both the upstream and downstream of coal preparation, stressing clean coal technologies for coal utilization. It not only discusses the sustainability of coal preparation, but also considers the governance and management issues that come with fulfilling economic, social and environmental obligations of a sustainable mining operation. Divided in three parts, the book explains the preparation of coking and non-coking coal, clean technologies, the principles of sustainable management and emerging management issues. The inclusion of case studies also provides a practical perspective for the planning and design of coal preparation activities and environmental management.

• Offers an integrated approach to pursue sustainable management between mining, coal preparation and final use of coal
• Explains the economic aspects of coal preparation in a modern/developing society with zero-waste concept
• Compiles the best technologies from around the world
• Uses India, a developing country, as a case study to apply technologies where there is maximum potential for application and benefit

Part I

General

Outline

• Chapter 1 Introduction
• Chapter 2 Coal Usage and Control of CO₂ Emissions
• Chapter 3 System Design of Coal Washing
• Chapter 4 Coal Sizing
• Chapter 5 Wet Cleaning Process by Major Unit Operations
• Chapter 6 Dry Cleaning Process

Chapter 1

Introduction

Abstract

Coal preparation is key to the realization of a clean coal technology. It acts as a bridge between producing mines and customers. A strategic plan for sustainable coal preparation has been created. There are different factors that determine the characteristics of quality of mined coal. The dilution takes place due to: geologic, mining and mine supervision. Raw coal quality deteriorates during mining. If dilution is restricted at this stage, there is a great deal of relief in the coal preparation plant. Control of dilution during surface and underground mining has been separately dealt with. The introduction of a new system of grading by gross calorific value has paved the way for noncoking preparation to become more rational. Clean coal technology through precombustion, combustion and postcombustion is discussed in this chapter and the zero waste approach is advocated. The growing implementation of clean coal technologies will also accelerate the use of coal as a primary source of energy.

Keywords

Dilution; characteristics; grading; preparation; precombustion; combustion; postcombustion; coking; noncoking; zero-waste

1.1 The Objective

As coal has been and will continue to be an essential material for the development of society, it warrants sustainable development and management. Appropriate management techniques need to be implemented according to the juxtaposition of natural baseline values with human impacts. Since coal preparation starts at the mine face, the objective of this book is to discuss the upstream as well as the downstream of coal preparation. In addition, management issues are discussed along with the sustainability of coal preparation. The coal preparation plant, a component of the mining complex, has to fulfil all the obligations of sustainable mining operations, such as: economic, social, environmental and governance. In order to achieve improved, clean and sustainable results, an analysis of the complete picture needs to be conducted. The management aspects of an industrial plant are considered as part of an integrated study along with the mine operation. This chapter is a link between mining and preparation in addition to serving the obvious purpose of introduction. To keep the coal preparation procedure in order, consistent and appropriate quality of raw coal feed are key factors, amongst others, to the success of the operation. Fig. 1.1 shows strategic plans for sustainable coal preparation. Coal preparation is considered to be a primary stage for implementation of clean coal technology (CCT).

Figure 1.1 Strategic plans for sustainable coal preparation.

1.2 Preparation of Coking Coal

The scenario of coal preparation in India is quite different from those prevalent in many other countries. Indian coal is difficult to wash because it has a high percentage of near gravity material. Low recovery of clean coal, greater yield of middlings and poor elimination of dirt are some of the typical washability characteristics of Indian coals, meaning that lowering of the ash content to below 10% is almost impossible. Although steel plants in other countries would not accept coking coal with an ash content above the standard threshold, Indian steel plants have been forced to adapt the technology to enable steel making with coking coal with a higher ash content of 17%.

Coking coal supplied to steel plants is required to meet the desired quality parameters. Over time, the problems are worsening because of the gradual depletion of low-ash coking coals and so stretching resources to the limit. There has also been considerable deterioration in the quality of feed coal. This has badly affected the performance of washeries in terms of yield and capacity utilization. Also, the old washeries of Coal India Limited (CIL) are facing additional problems. Since the installation of the first washers in India in 1951, a number of washeries have been built and many are under construction. With the increased consumption of stretched resources, it is imperative that corrective measures are speedily implemented, both during the design and operation of coal preparation plants.

1.3 Preparation of Noncoking Coal

In fact, coking coal washing has been practiced for some time in India. It has now been proven that the preparation of noncoking coal is beneficial, especially for power generation. Noncoking coal is also known as thermal coal because of its utilization of the heat value. This preparation procedure has many advantages: supply of consistent quality and size, improved efficiency of power plants, reduced load on transportation carrying dirt material along with coal, increased use of inferior-quality raw coal and improved environmental benefits. Ash limits for different consumer sectors are indicated in Fig. 1.2 and detailed specifications are provided in subsequent chapters.

Figure 1.2 Ash limit for different consumer sectors.

1.3.1 The New Policy

As per a directive of the Ministry of Environment and Forests (MoEF), Government of India, all coal-based thermal power stations (TPSs) shall use raw or blended or beneficiated coal with an ash content not exc...