Development of Autonomous Plasma-Fuel Systems and Coal-Fired Power Boiler Modernization
Tech Area / Field
- NNE-FCN/Fuel Conversion/Non-Nuclear Energy
- NNE-EPP/Electric Power Production/Non-Nuclear Energy
3 Approved without Funding
Kazakh National University / Combustion Problems Institute, Kazakstan, Almaty
- Almaty Power Consolidated, Kazakstan, Almaty\nKazakh National University / Scientific Research Institute of Experimental and Theoretical Physics, Kazakstan, Almaty
- Zarak Systems Corporation, USA, CA, Sunnyvale\nImperial College London / Department of Mechanical Engineering, UK, London\nPennsylvania State University / Energy Institute/College of Earth and Mineral Sciences, USA, PA, University Park\nUniversity of Illinois / Department of Natural Resources and Environmental Sciences / Illinois State Geological Survey, USA, IL, Champaign\nUniversite de Rouen / CORIA-UMR 6614 Laboratory, France, Mont Saint Aignan
Project summaryThe objective of the project is to implement energetically effective and environmental friendly plasma technologies of boiler ignition and pulverised coal flame stabilization developed in the project K-476, to create autonomous plasma-fuel systems (PFS) implementing this technology on a demonstrative coal-fired boiler, to work out a three-dimensional mathematical model and program for calculations of power-generating boiler furnaces equipped with PFS, to compare operating parameters of the boiler furnace for the regimes of traditional burning and for plasma activation of coal combustion, to find optimal characteristics for the implementation of this technology in furnace units. The objective is stipulated by the necessity of more extensive use of low-rank solid fuels for electric and heat energy generation, by the necessity to reduce the fraction of deficient and expensive liquid and gaseous fuels used in heat-and-power engineering, metallurgy and other branches of industry and by ecological deterioration of the environment. It is well known that during low-rank coal burning the quality of its ignition and burning-out worsens and the volume of harmful dust and gaseous emissions (ash, nitrogen and sulphur oxides) considerably increases.
In heat-and-power engineering fuel oil and natural gas are used for low-rank coal ignition and flame stabilization, but it does not solve the problem. Their co-combustion with coal causes decrease in the main indexes of Thermal Power Plants (TPP) (boilers’ efficiency decreases, dust and gaseous pollutant emissions increase, high temperature corrosion of boiler’s heating surface increases, etc.). What makes the problem even more acute is formation of carcinogenic vanadium oxides during fuel oil burning and soot emissions in the process of fuel oil boiler ignition.
The research and technical-economic assessment carried out in the framework of the project K-746 show that plasma technology and PFS are the most perspective and not expensive means of complex solution of the above problems. PFS is a furnace unit with plasmatron and special equipment (plasmatron power supply source, starting device, etc.). The essence of the method of plasma coal activation and ignition suggested in this proposal is to heat air-fuel mixture by arc plasma up to the temperature of coal volatile emission and gasification of coke residue as a result of which, independent of the quality of initial coal, highly reactive heated two-component fuel consisting of fuel gas and coke residue is produced. The resulting fuel is intensively ignited and stably burns even in the cold boiler furnace when mixed with the secondary air. This method has been successfully approved at several heat power plants in Kazakhstan, Russia, Ukraine, Mongolia, China, Korea and Slovakia. However, it needs some improvements and optimisation for wide use at TPPs. Further wide application of this method is restrained by the absence of advanced calculation methods of working process in coal-fired boilers equipped with plasma-fuel systems (burners with plasmatrons) (Fig. 1). When plasmatron is used, the output parameters of plasma-coal burner are considerably different from those of existing pulverised coal burners. Reacting two-component fuel mixture enters a boiler. That causes changes in the main parameters of combustion process. As a consequence, complex investigation of boiler working process with account for plasma technology becomes especially important. It should combine computer simulation of the processes proceeding both in plasma-coal burner and boiler space, with experiments in laboratory and industrial conditions. Carrying out of such investigation will enable to predict the main parameters of the process in boiler’s space with burners equipped with plasma generators. It is necessary for designing new and optimisation of existing boiler units during their modernisation.
Fig.1 Plasma-fuel system (PFS)
The works to be done in the project framework refer to applied investigations. As a result, highly effective technology of low-rank power coal plasma activation and high-efficiency burners with plasmatrons will be developed and demonstrated. The project will enable to study operating parameters and to obtain optimal characteristics of plasma-fuel system operation in the conditions of the coal-fired thermal power plant. Project realisation will enable to reduce consumption of deficient and expensive liquid and gaseous fuel in power engineering and other branches of industry; to increase efficiency of solid fuel burning and to improve coal burning plants environment due to minimisation of harmful dust and gas emissions.
It is planned to realize the following tasks in the framework of the project:
- To carry out numerical analysis of multi-component heterogeneous systems (coal + air) with reference to PFS using universal program for thermodynamic calculations TERRA.
- To make the experimental stand for PFS testing before their delivery to the TPP and experimental investigation of plasma activation of air-fuel mixture of burning power coal.
- To carry out experimental investigations of thermochemical plasma coal preparation for burning. To study end-products of coal thermochemical preparation for burning, to make chemical and X-ray analysis of initial coal and coke. To use for experimental investigations controlling and measuring equipment received in the framework of project K-746.
- To develop three-dimensional mathematical model of heating, aerodynamics and kinetics of thermochemical transformations and combustion of pulverised coal flame in the boiler furnace equipped with PFS.
- To fulfil kinetic, thermal and dynamic analysis with the help of mathematical model of moving, high-temperature heating and thermochemical transformations of coal dust fuel at oxidant flow. For research of the processes running in the chamber for electrothermochemical preparation of fuel to burning, it is planned to use step-by-step method of calculation, which is being developed now.
- To develop the method of step-by-step PFS calculation and to carry out kinetic, thermal and dynamic analysis using mathematical model of motion, heating and thermochemical transformations of coal dust fuel in the PFS by the program “Plasma-coal” developed in the project K-746.
- To carry out numerical investigations of PFS and working regimes of BKZ-420 boiler furnace using one-dimensional and three-dimensional mathematical models.
- To compare experimental and calculation data and to introduce corrections in the models. To issue initial data and technological recommendations for PFS designing and mounting on the BKZ-420 boiler of ATPP-2. To carry out technical and economic assessment of the efficiency of PFS operation at BKZ-420 boiler of ATPP-2.
- To examine the BKZ-420 boiler of TPP-2, Almaty, in order to provide it with PFS. To develop PFS design with its adjustment to the ATPP-2 BKZ-420.
- To manufacture and test the main PFS components at the experimental stand.
- To mount stationary equipment to provide PFS operation on the boiler (1000 kVA transformer, unit KRU-6, air compressor, water pumps, etc.).
- To manufacture, to mount and to adjust autonomous PFS with the systems of power-water-and-air supply at the boiler BKZ-420.
- To test PFS in the regimes of the boiler BKZ-420 starting up and stabilization of pulverised coal flame without use of fuel oil.
- To prepare operating documentation and to train personnel of Almaty TPP-2 how to work with PFS on the demonstrative industrial boiler BKZ-420.
The project will enable to realize the following ISTC objectives:
- Highly qualified scientists specialised in the field of plasmachemistry, plasma technologies, thermal and electrical engineering as well as scientific potential of specialists connected to weapon development will be involved with their subsequent reorientation into advanced technologies of civil branches of industry (power engineering and metallurgy);
- Project realisation will promote integration of Kazakhstani scientists into scientific world community. It is planned to participate in International scientific and technical conferences with publications of the main project results to expand the field of plasma technology applications and their marketing.
- Researches done in the framework of the project will be of applied nature. They will promote use of plasma technologies in peaceful purposes and especially in the field of environment protection, power generation and new energy carriers. These researches will be of scientific importance for the development of fundamental science in the field of plasma chemistry, chemistry of solid fuels, thermal physics, ecology and plasma technology.
- Project implementation will considerably contribute to the solution to national and international technical problems related to replacement of expensive and deficient gaseous and liquid fuels from coal burned power engineering with simultaneous improvement of ecology-economic indexes of power plants.
- As a result of project realization a demonstrative industrial boiler equipped with PFS for efficient and ecologically sound burning of low-rank coals without use of the second fuel (fuel oil) will be created. Equipment of a demonstrative boiler with PFS is implementation of plasma technology of fuel use developed in the framework of the project K-746.
Plasma technology and PFS is new and highly competitive method. It will promote transition to market-based economy in the commercial industries. At the present time the technology and PFS are unique and have no analogues.