CONTENTS OF REPORT
The conducted Techno-market survey report comprises of thirteen chapters as named below:
CHAPTER IINTRODUCTION-contains air pollution and its hazardous effects to
living beings / plantation / material.
CHAPTER IITechnologies prevailing in India – Indian scenario in general, air
pollution law, emission standards and status of air pollution control.
Sub chapters of CHAPTER II mainly comprise of brief of different
process technologies, air pollution and air pollution control technologies and all the relevant available features in cement industry, integrated iron and steel plants, Thermal power stations, aluminum, zinc and copper smelters and foundries.
CJAPTER IIIIndustrial air pollution control technologies world scenario-contains general overall picture of air pollution, acid rain, approaches to control acid rain, overview of control technologies and clean air act.
Sub chapter of chapter III touch on the air pollution control technologies as being implemented in different countries like Russia, Japan, Germany, Europe, Poland, USA, Norway, Austria, Holland and Switzerland respectively
CHAPTER IVStatus of air pollution control technologies / technological options in India.
CHAPTER VStatus of air pollution monitoring in India.
CHAPTER VIAir pollution control equipments selection / options.
CHAPTER VIITechnology of source control / clean technologies.
CHAPTER IX-BYPRODUCT / REUSE through air pollution control technologies.
CHAPTER XI-General preconditions / main issues / suggestions / recommendation / action plan.
CHAPTER XIIImportant / impressive work of some of Indian experts.
CHAPTER XIIIReferences-contains names of experts, agencies, institutions, books journal referred to prepare the report.
IMPORTANT FEATURES / POINTS FOR CONSIDERATIONS
FOR DIFFERENRT INDUSTRIES :
CEMENT INDUSTRY:Indian cement industries a pioneer in accepting and implementing the newly developed technologies. Cement is one of the largest pollution generating industry, having pollution generated at every stage. Most of the modern cement plants in India are installed with ESPs, bag filters, multicyclones, pocket filters etc. old plants are also retrofitted. Re-utilization of by-pass kiln dust in cement industry is showing importance.
INTEGRATED IRON AND STEEL PLANTS: Technologies as adopted for the treatment of air pollutants are conventional ones used globally. Success of any one method at a particular plant does not mean its universality and the methods for treatment are to be tailored in view of the local industrial environmental suitability.
THERMAL POWER SYSTEMS: Thermal power stations are one of the major sources of air pollution, which is in the form of fly ash, dust , Sox and NOx emissions from the stack and coal dust from the coal handling, conveying and crushing systems. The quality of coal used in India for the power generation is poor having high ash content and low volatile matter, which requires larger quantity of coal to be burnt. Indian coal is also low in sulphur having high ash content and low volatile matter, which requires larger quantity of coal to be burnt. Indian coal is also low in sulphur having extremely low sulphur / ash ratio leading to a very high resistively and needing excess air for operation. Re-use of fly ash in the manufacturing of bricks, partial replacement of cement in concrete and fly ash, ferro cement beams and roofing sheets have potential uses in the construction projects.
ALUMINIUM SMELTERS: Aluminum holds a great promise in the industrial development of India in view of its importance for use in the various strategic sectors. India has very large bauxite deposits of the order of about 2650 million tons. The production technology adopted in India involved two main stages which are:
Production of alumina from bauxite by Bayer’s process.
Extraction of aluminum metal from alumina in electrolytic cells by hall-heroult process.
The environmental impacts associated with the mining industry are mainly ecological balance are to be taken. Emitted dust is controlled through spraying water using wet scrubbers etc.
The air pollution caused mainly by the fluorides in the aluminium smelter industry and it comes out of the aluminium reduction cell. The excessive intake of fluorides can cause fluorosis in human beings and affect animal life. The latest technique accepted for the control of fluorides is by using Dry Scrubbing system for the smelter gases, controlling pollution and also recycling the fluorides thereby affecting economy in the consumption of cryolite and Aluminium fluoride.
ZINC SMELTERS: Processes like blasting, crushing and grinding of ore generate a fine dust, which it allowed to disperse may cause air pollution. Gases like SO2, NOx, CO2, or HC etc. are not generated. Dust emitting sources are identified and appropriate facilities are installed to prevent dust entering the local environment. At smelting units, dust containing sulphide and oxides of metals, acid mist, SO2 and metal fumes are main air pollutants. Gas cleaning and dedusting facilities and sulphuric acid plants have been incorporated to take care of these emissions.
COPPER SMELTERS: All the copper smelters working in India are being managed by M/S Hindustan Copper Ltd., a Govt. of India enterprise. HCL is engaged in mining of the copper ore, its beneficiation smelting and refining to produce electrolytic cathode copper, wire bars and cathodes. Besides this the by-products produced are Sulphuric acid, Phosphatic fertilizers, Nickel Sulphate, Selenium, Silver and Gold. HCL has formulated schemes for arresting gaseous sulphur dioxide emissions by implementations of new acid plants to use the emitted SO2.
FOUNDRIES: Foundries are relatively small factories which are frequently used where pig iron and the scrap metal has to be melted down and cast into moulds with very intricate shapes. Their air pollution problems, dust and fumes from the material handling and smelting are similar to steel mills but on a much reduced scale.
In moulding and core making shops, the pollutants emitted are – Dust, Carbon monoxide, Sulphur dioxide, Hydrogen sulfide, Ammonia, Furfural alcohol, Touene, Benzene, methanol, Xylene, Phenol, Formaldehyde, Cyanide, Iso-cyanates, Dimethl – ethl amine, Acrolein and Triethlamine. The generated pollutants have to be caputured and conveyed through duct to the suitable cleaning system which comprises of (1) dry dust removal equipments (2) wet dust removal equipments and (3) chemicals.
The constraints for installing effective air pollution control systems by the existing plants in India are :-
To have a cost effective technology for the retrofitting of the existing control technologies.
Problems of mobilizing financial resources for small industries, to bear huge costs of installing control equipments / technologies.
Technology gap exists in the following areas for reducing pollutant emissions in India
.flue gas desulphurisaiton
- DENOx systems
- Dry scrubbing technology for the removal of fluorides from aluminium smelters.
- Specialized technology for cleaning CO rich blast furnace gases and gases from steel convertors in special gas tight multistage variable throat venture.
- Energy management systems for ESP and fabric filters particularly for fly ash application.
- Special gas absorption system for the removal of toxic gases.
- The international companies are engaged in upgrading their technologies keeping in view:providing set emission standards
- educing hazards
- recycling wastes
- reducing hardware requirements
- optimizing energy requirements
- inducting new/cleaner processes
The latest development in the technological up gradation is in the field of removal of fluorides emitted during the primary gas cleaning from aluminium smelters, by means of dry scrubbing.
The indigenization of equipment manufacturing is making rapid progress, reducing the foreign exchange content to minimum. The present installed capacity for the manufacturing of air pollution equipments is more than sufficient in India to meet the industry’s requirement. Some of the units are closed or are underutilized due to:
1. Lack of awareness and low pace of implementation of air pollution control.
2. Lack of fiscal incentives for industries to meet the emission standards.
The technology of source control is interdisciplinary and includes working out of the economic feasibility, planning standards, application of specific hardware, fuels and materials with low emission potential. The control strategy depends on the selection of the best air pollution control measures among the available ones. Following four factors for reducing four factors for reducing emissions from a polluting process are –
1. Eliminating the source
2. Regulating the location of the source
3. Modification of the process/using cleaner technology
4. Reducing or eliminating emissions, using control devices and systems.
