Julia Knysh

Faculty of ecology and chemical technology

Department

Speciality: Chemical technology of fuel and carbon materials

Theme of master's work:

Research of coking process of coal charge with the use waste of coke and chemical production

Scientific adviser: Saranchuk Viktor

Abstract

INTRODUCTION

      One of the pressing problems of coking industry is the problem of expanding the raw material base by bringing coal of low-caking charge (Gas and low-caking coal), instead of the deficit high-caking coal.

      To solve this problem we can use different methods of preparation and coking coal charge, in particular is compression of coal charge by its partial briquetting. The most effective briquetting coal charge with binders: addition of binders ensures the procurement of strong briquettes reducing the part of particle charge, which can be briquetted, and increases caking capacity of briquetted charge. It must result in increasing of coke hardness.

      Coal tar pitch and bitumen are used as binders. However, these products are used in other important industries. At the same time the coke plants generate a large quantity of resinous waste every year. They can’t find proper application. The lack of an effective method of disposal of tarry waste is a major reason for the waste dump of majority of Coking plants. It is a simple and relatively inexpensive method of waste destruction, but due to changes in requirements to the environmental protection, it can not be used in the future.

      It is necessary to establish that other ways of waste destroying (burial, combustion and biodegradation) are totally ineffective in this case. The research of use of resinous waste of coke production as a binder for the partial briquetting of coal charge was carried out.

      Actuality of theme. Use of waste production is a very actual problem because one of the vital problems of coke industry is the problem of resinous waste recovering, which is not used. The lack of an effective method of disposal of tarry waste is a major reason for the waste dump of majority of Coking plants. However, the ecological situation will not allow disposing waste in this way in the future.

      Scientific significance consists in the possibility of use of coke production waste as a binder in partial briquetting of coal charge to the coking and getting qualitative coke.

      The practical value of the work consists in getting coke using waste of coke production of required quality.

PLANNED EXPERIMEN

      Factorial experiment is realized by means of the planning matrix, in which we use the encoded values of factors.

       Thus, the main task of the study is determination of the response function of a second-order orthogonal design, and getting optimal conditions for management of the process under consideration.

      As the technological parameters of the production of coke using briquettes and waste (coal sludge 67%, acidic tar 30%, polymer 3%), which are the most important for their quality, were selected the following:
            – Percentage of binder which is added to the briquettes, SV;
            – Compacting pressure of briquettes, P.

      You can see the variability interval of two major influencing factors below:
            Binder content (SV): 14-18%;
            Pressure (Р): 300-700 atm.

      Four compositional plans were developed for the experiment. In one case the charge is briquetted, in the second – coal grade SS is briquetted, in the third – coal grade G is briquetted, in the fourth – a mixture of grade SS and G in equal ratio (1:1) is briquetted. These plans are presented in Table 1.

Table 1 - Second-order orthogonal design for two factors

      The data were obtained after the factorial experiment, and then they were processed in a special software package. And also we received plastometrical curves shown in picture 1

Picture 1 – Plastometrical curves of factorial experiment

      Calculations made it possible to get a regression equation, which shows the connection between factors and their responses characterizing the quality of coke.

      The values of regression factors in the equations show the influence of each factor or their combination on the value of the output parameter.

      A statistical analysis showed that equations given in the Table 2 are appropriate to the experimental data with the confidence level 0,05. Thus, the obtained system of equations is an exact mathematical model of the process of coke obtaining of the given quality.

Table 2 - Key regression equation of coke quality indicators in coded form

      Also as a result of calculation the response surface were got for these two parameters (coke hardness and abradability) which are presented on a picture 2.

Picture 2 – Surface response to parameters of coke hardness and abradability

      The obtained data show that the greatest coke hardness (Pr) is 37.83%. It is achieved under minimal pressure (P) (picture 2) and small content of binder (S). The lowest abradability (Is) (picture 2) is 31.30% - at a minimum pressure (P) and the minimum content of binder (S).

CONCLUSION

      Method of use of coke production waste as a binder in partial briquetting of coal charge before coking is implemented for industrial use. It makes possible to use waste of coke production reducing the influence of waste on the environment.

LIST OF LITERATURE

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11. Патент РФ 2186823
    Способ подготовки угольной шихты к коксованию.

© DonNTU Julia Knysh 2009