Combustion/ Incineration

Introduction

It is the process of direct burning of wastes in the presence of excess air (oxygen) at high temperatures (about 8000C) liberating heat energy, inert gases and ash. Net energy yield depends upon the density and composition of waste, percentage of moisture and inert materials which add to the heat loss, ignition temperature, size and shape of the constituents, etc. Combustion results in transfer of 65-80 per cent of the heat content of the organic matter into hot air, steam and hot water.

• Suitable for high calorific value waste (paper), plastics, hospital wastes, etc.;
  
• Units with continuous feed and high throughput can be set up;
  
• Thermal Energy recovery for direct heating / power generation;
  
• Relatively noiseless and odourless;
  
• Low land area requirement;
  
• Can be located within city limits, reducing cost of waste transportation; and
  
• Hygienic.
  

Disadvantages

• Least suitable for high moisture content/ low CV wastes and chlorinated wastes
  
• Excessive moisture and inert content in waste affects net energy recovery; Auxiliary fuel support may be necessary to sustain combustion;
  
• Toxic metals may concentrate in ash;
  
• In addition to particulates, SOx and NOx emissions, chlorinated compounds, ranging from HCl to organo-compounds such as dioxins, and heavy metals are a cause for concern, which requires elaborate pollution control equipment; and
  
• High capital and O&M costs.
  

Limitations/ Constraints

The growth of this sector has been affected on account of the following limitations/ constraints:

• Waste-to-Energy is still a new concept in the country;
• Most of the proven and commercial technologies in respect of urban wastes are required to be imported;
• The costs of the projects especially based on biomethanation technology are high as critical equipment for a project is required to be imported.
• In view of low level of compliance of MSW Rules 2000 by the Municipal Corporations/ Urban Local Bodies, segregated municipal solid waste is generally not available at the plant site, which may lead to non-availability of waste-to-energy plants.
• Lack of financial resources with Municipal Corporations/Urban Local Bodies.
  
• Lack of conducive Policy Guidelines from State Govts. in respect of allotment of land, supply of garbage and power purchase / evacuation facilities.
  

Cost: Combustion/Incineration 6-7

Financial Support

The scheme for providing financial support for waste-to-energy projects is presently under review and accelerated programme on energy recovery from municipal and industrial wastes is being development for providing a major fillip to this sector.

Implementation

Waste-to-energy projects can be set up municipal corporations, other urban local bodies, government institutions, and private developers having technical and managerial capabilities for implementing such projects on the basis of Build, Own, and Operate (BOO); Build, Own, Operate, and Transfer (BOOT); Build, Operate, and Transfer (BOT); and Build, Operate, Lease, and Transfer (BOLT). The proposals are to be sent to the MNES after completing all tie-ups for waste procurement, sale and evacuation of power, pollution control, etc. In cases where debt financing is involved, IREDA, other financial institutions, and commercial banks are required to forward proposals alone with their Appraisal Note. An advance copy of the proposal may be sent to the MNES.

Potential

There exists a potential for generating an estimated 1700 MW of power from the urban and municipal waste, and about 1000 MW from industrial wastes in the country. The potential is likely to increase further with economic development.

Achievements

A total of 27 waste-to-energy projects have been completed as on 31 March 2005 in India, with an aggregated installed capacity of 45.50 MW. In table gives the state-wise cumulative achievements as on 31 March 2005.

Cumulative achievements as on 31 March 2005

Main Application: Energy Recovery from Wastes

Contact:

Ministry of Non-Conventonal Energy Sources,
Govt. of India
Block-14, CGO Complex, Lodi Road
New Delhi – 110 003
Tel: 91 11 2436 0707/ 2436 0404
Fax: 91 11 2436 1298