Smokeless Coal Briquette
Development of a Smokeless Ecologically-Friendly Coal Briquette Technology
Tech Area / Field
- NNE-FUE/Fuels/Non-Nuclear Energy
3 Approved without Funding
Kazakh National University / Combustion Problems Institute, Kazakstan, Almaty
- Kazakh National University / Scientific Research Institute of Experimental and Theoretical Physics, Kazakstan, Almaty
- Zarak Systems Corporation, USA, CA, Sunnyvale\nApplied Computational Fluid Analysis, Canada, Thornhill\nApplied Plasma Technologies, USA, VA, McLean\nUniversity of Illinois / Department of Natural Resources and Environmental Sciences / Illinois State Geological Survey, USA, IL, Champaign\nImperial College London / Department of Mechanical Engineering, UK, London
The aim of this project is to develop a smokeless briquette of low toxic emission, along with a technology for its economic production.
Solid fuel is a principal source of air pollution: particulate matter, sulfur and nitrogen oxides, unburnt combustibles, including carbon monoxide, and carcinogenic polycyclic aromatic hydrocarbons (PAH). Numerous efforts are currently being made at many large-scale combined heat and power facilities aimed at reducing the emissions of nitrogen, sulfur and carbon oxides. However, insufficient attention is being given to the prevention of PAH formation. The presence of such compounds in smoke plumes can be far more dangerous to the biosphere than nitrogen and sulfur oxides. PAH compounds are one of the strongest carcinogens. Most of the benz(α)pyrene and polycyclic aromatic hydrocarbons are adsorbed on the surfaces of solid particles (smoke) emitted to the atmosphere. The smallest of these are capable of deep pulmonary injection.
PAH emissions are particularly significant for smaller-scale grate-fired industry boilers and domestic installations. These appliances use coal or wood fuels in briquette form. Well-established data reveal that they emit the order of one hundred times more carbon monoxide per unit of useful thermal output than thermo-electric power stations. Moreover, it is found that the PAH concentrations in the products of combustion of grate-fired furnaces are some one thousand times greater than those of power stations. For economic and supply reasons, it is unlikely that the briquetted fuels will to any significant extent be replaced by oil in the foreseeable future. The proposed research therefore focuses on defining a feasible and accessible technology to reduce PAH emission consequent of briquette combustion.
The contemporary high-carbon content briquette is difficult to ignite, requiring the use kerosene or other volatile liquids. The major part of PAH release occurs during the ignition phase of the combustion process. For improved understanding of the PAH formation processes, the proposed research undertakes to study solid fuel combustion products, emphasising those resulting from different fuel additives. The project will provide quantitative data in regard to the toxic pollutant concentrations emitted during the ignition and combustion of contemporary coal briquettes and the effect on these emissions of the incorporation in the briquette of selected additives. For the preferred mixture of fuel, binder and additive, a production technology will then be elaborated.
The project participants are specialists in the field of plasmochemistry, pyrolysis processes and solid fuel combustion. They have considerable experience in the technology of briquetted fuels and the chromatographic analysis of their combustion products. The project deliverables will be a chemical recipe for a smokeless briquette of low toxic emission properties along with a technology description enabling its economic production. The project implementation complies with the aims of the ISTC, namely: the reorientation of former CIS defence scientists to peaceful researches; their integration into the international scientific community; and their involvement in supporting fundamental and applied research in the field of environmental protection.
The chemical strategy will involve the use of catalytic additives, which neutralise smoke formation and decrease both the ignition temperature and the concentration of unburnt material in the combustion products. The ignition temperature will be suppressed to the extent that a match will prove successful. The active additives to be studied will include alkaline and transition metal compounds such as sodium, iron and copper compounds. Mixtures composed of available plant materials and available waste products, which combine catalytic activity with non-toxic properties, will be considered. The production technology will seek a clean, non-toxic starch containing binder. The composition of the final and economic product will consist of approximately 5 % binder and 1 % additive. Dual role ‘binder-plus-additive’ compounds will be sought.
In an additional and novel approach, the proposed research will consider a compound pellet fuel consisting of an inner core enveloped in an outer layer. Coal grinding will be implemented to facilitate control over the sizes, density and composition of the inner core and outer layer, depending on the properties of the initial coal. The outer layer will contain the binder and the additives. As such it will be easily ignitable. As it combusts it will in turn ignite the inner core of conventional briquette material. The toxic emissions of the core will be consumed by the clean combustion reactions of the outer layer. Such a fuel would be ideally adapted for cooking.
In sum, the new data obtained during the course of this project will enable the effects of chemical additives on the toxic emission from solid fuel combustion to be established and favourably implemented. In a parallel undertaking, a protocol for the economic production of the non-toxic briquette will be developed. The implementation of the proposed project corresponds to the priorities of the Republic of Kazakhstan in relation to international environmental standards and to supplying its citizens with an ecologically safe fuel.
The role of the foreign collaborators is to promote contacts with overseas scientists working in related research fields. They will review the ISTC technical reports and assist at joint seminars.