THESIS ON MASTER’S DEGREE RESEARCH

“Research of the influence of the processing with inorganic matters on the coke quality”.

The Ukrainian conversion form the planned type of economy to the market one was accompanied with the decrease in the bulk coke output (it was lowered twice), and this, however, didn’t change the traditionally problematic position in coking raw material base.

It can be asserted that the shortage of high-caking coal has been replaced with the acute shortage of highly metamorphosed low-caking thinning agents, which has already resulted in 2.4% growth of coal volatile matter yield out of the furnace charge, on average, and approximately 1.7% drop in bulk coke output.

The unsatisfactory condition of the Ukrainian coal mining industry in whole only underlines the impressive success of the coal mining company called ”Shakhta Krasnoarmeyskaya Zapadnaya ¹1 ”mining the d₄ coal stratum. Having been set in operation in 1990, the first starting complex, with the designed output of 1.5billion tons of coal a year, has reached the output of 1.74 billion tons by the year 1996, and 4.6 billion tons by 2004.

The characteristic feature of the little reduced coal is its high coking ability with relatively low caking (ó = 12 — 14 mm). The low sulphur content (S_t^d = 0,7 - 0,8 %) along with the high cokeability provides this coal utilization preference as the main furnace charge component for coking.

To define the engineering decision on the efficient utilization of coal mined by ”Shakhta Krasnoarmeyskaya Zapadnaya ¹1 and the influence of inorganic matters on the coke quality, a full-factor experiment carried out in shop conditions using the box coking technique has been conducted by us along with the “Makeyevcocs” PLC (table 1). Due to this technique, the coking process of the experimental charge goes on in the real conditions in which the industrial cookery run.

To achieve the result three charges with different content of the coal were prepared and coked. To compile the charges brand K coal (undergoing research) and base charge taken out of the ready charge production line in coal-preparing shop (containing no coal under research) were separately selected. After that the experimental charges to coke with the brand K content of 30, 50 and 70% were made. The brand K content in the charge was chosen so, that the top edge should exceed the lower more than two times and should guarantee the standard behaviour of the coking process.

Table 1 – Plan of the experiment

 

Experiment number	Coded variables		Natural variables
	Õ1	Õ2	Brand K content, %	Coke processing, kg of inorg matters/t of coke
1	-1	-1	30	0
2	+1	-1	70	0
3	-1	+1	30	4,8
4	+1	+1	70	4,8
5	-1	0	70	2,4
6	0	+1	50	4,8
7	-1	0	30	2,4
8	0	-1	50	0
9	0	0	50	2,4
10	0	0	50	2,4
11	0	0	50	2,4

Table 2 gives data on the technical analysis and dissemination of obtained charges.

Table 2 – Technical analysis of the charges

Charge	Technical analysis, %					Dissemination,mm
	Wr	Ad	std	V	ydaf	+ 6 mm	6- 3 mm	3-0 mm
Base	9,9	7,8	1,34	31,2	33,8	14,3	14,6	71,1
1 (B 70%, Ê 30%)	9,1	8,0	1,16	29,9	32,5	21,5	16,3	62,2
2 (B 50%, Ê 50 %)	9,2	8,1	1,1	29,1	31,7	21,5	14,3	64,2
3 (B 30%, Ê 70%)	8,9	8,2	0,98	28,1	30,5	22,0	14,8	63,2
Brand Ê (Krasnoarmeyskaya Zapadnaya ¹1)	8,2	7,9	0,75	27,1	29,5	—	—	—

Technical analysis and granulometric composition of the obtained coke received as a result of experimental charges coking is represented in Table 3.

Table 3 - Technical analysis and granulometric composition of the obtained coke

 

 

Coke	Technical analysis, %				Granulometric composition, mm
	Wr	Ad	s,d	V*	+80 mm	80 - 60 mm	60 - 40 mm	40 - 25 mm	25 - 0 mm
1 (B 70%, Ê 30%)	4,7	10,1	0,9	0,5	34,2	37,6	17,3	5,6	5,3
2 (B 50%, Ê 50 %)	0,44	11,0	0,81	0,6	39,7	31,3	17,8	5,9	5,3
3 (B 30%, Ê 70%)	8	11,3	0,75	0,6	43,2	33,2	14,2	4,7	4,7

Quality values CRI (coke reactivity in hot state) è CSR (coke stability undergone the reaction in ÑÎ₂   environment) for these cokes were defined with the accordance of the ASTM - D5341-99 standard developed by the Japanese company Nippon Steel Corporation.

Table 4 reveals the experiment results.

Table 4 – Results of the Planned experiment

 

¹ of the experiment	Brand "Ê" content	Processing	CRI, %	CSR, %
1	30%	—	43,22	34,92
2	30%	—	39,82	39,65
3	50%	—	35,63	43,35
4	50%	—	34,7	45,11
5	70%	—	34,66	46,16
6	70%	—	34,79	47,63
7	30%	4,8	41,35	34,93
8	30%	4,8	40,41	37,69
9	50%	4,8	34,31	47,57
10	50%	4,8	33,12	46,49
11	70%	4,8	28,78	53,06
12	70%	4,8	36,02	49,48
13	30%	2,4	41,16	37,03
14	30%	2,4	39,16	40,88
15	50%	2,4	36,12	43,31
16	50%	2,4	37,39	41,23
17	50%	2,4	33,89	49,05
18	70%	2,4	36,96	44,66
19	70%	2,4	30,3	52,85

After the mathematical-statistical processing of the results the regress ional equations describing the influence of Xi and Õ₂ factors on CSR and CRI values:

ÑRI = 58,139 - 0,741375*X1 + 0,238715*Õ₂ + 0,0058*Õ₁²-0,0088*Õ₁*Õ₂ - 0,02199*Õ₂²

(Correlation factor R² = 98,0%)

CSR = 20,5792 + 0,723292*X₁ - 0,759201*Õ₂ - 0,0050*Õ₁² +0,02786*Õ₁*Õ₂ - 0,04257*Õ₂²

(Correlation factor R² = 98,08%)