RU2343179C1 - Development method for layerwise carbonisation of charge, containing products of brown coal thermal treatment - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: into initial charge, containing mixture of gaseous, gaseous rich, rich, coke and mineraling-sintered coals, additionally it is introduced modifying agent in the form of preliminarily heat-treated brown-coal resin of brown coal rapid pyrolysis. In the capacity of mineral filler it is introduced mineraling-sintered coals or its mixture with "rich" admixture in the form of coal of the second coke at content of mineraling-sintered coals in charge in amount 4.32-14.32 wt %, and coal of the second coke in amount 6.09-13.09 wt %.

EFFECT: expansion of carbonisation raw materials base and increasing of bulk-coke yield with improved physical-mechanical properties.

3 cl, 1 ex, 3 tbl

Description

The invention relates to methods for preparing coal blends for layer-by-layer coking with the aim of producing metallurgical coke and related chemical products of coking (coke oven gas, crude benzene, resin).

The development of the coke industry at the present stage largely depends on the expansion of its raw material base. In connection with the growing deficit of coke and fat coals, the question arises of the need for their economical spending and finding ways to replace the latter in coking charges.

In connection with the collapse of the USSR, two of the four largest, well-developed coal basins - the main suppliers of coal for coking (Kuzbass, Donbass, Karaganda and Pechorsky) - were abroad. However, a number of Russian coke and chemical plants and at present, along with the coals of the Kuzbass and Pechora basin, use coals of Ukraine and Kazakhstan (Donetsk and Karaganda) in layered coking charges. Therefore, the problem of expanding the raw material base of coking coals with a simultaneous increase in the yield of target coke and improving its mechanical properties by partially replacing scarce coke coals in coking blends with non-deficient low-caking coals with filling the deficiency of non-volatile liquid compounds in the charge by adding heat-treated heavy tar with high-speed brown pyrolysis relevant technically significant and important for the coke industry. It is proposed to use low-ash low-sulfur brown coals of the Kansk-Achinsk basin (KAU) or brown coals of Mongolia Baganuursky (BN) and Tugrugnuursky (TN) for high-speed pyrolysis in order to obtain the maximum amount of resin with its subsequent heat treatment and addition to coking charges. It is possible to use brown coals and other deposits according to technical indicators (humidity, ash content, sulfur content), close to similar indicators of Kansk-Achinsk or Mongolian brown coals.

Closest to the claimed one is a method of preparing for charge coking, including fine-grained brown coal half-coke (BOD) of high-speed pyrolysis as an exhausting agent, by grinding the charge components, mixing coal and BOD, drying the mixture to a residual moisture of 2.5-4%, followed by coking ( AS USSR, No. 1214718, BI, publ. 02/28/1986 / V.M. Dinelt, M. B. Shkoller, I. Timofiva, E. B. Ushakov) (prototype).

It is impossible to use additives in thin quantities in the charge due to the deficiency in the coke charge of its own liquid-moving thermolysis products of the coals of the charge. Note that Donetsk coals are characterized by the following yield of mobile plastic mass,% of the combustible mass of coal: gas (G) 5-25; fatty (W) 35-70; coke (K) 20-35; lean sintering (OS) 1-20.

Traditionally, the charge of layered coking is composed of several components (groups, mine groups), and many of its properties are not an additive quantity (yield of liquid-moving products in a centrifugal field, apparent viscosity, gas permeability, swelling, etc.).

Coal blends of coke-chemical enterprises in a plastic state are characterized mainly by the following indicators: expansion index (IGI-DMetI) 12-39 mm; the thickness of the plastic layer is 14-20 mm; Horn Index (RI) 50-65.

It should be noted that the gas coals in the blends reduce the bursting pressure and facilitate the delivery of coke, but they give fine coke with low mechanical strength. Fatty and gaseous coals in the charge provide a normal structure, high strength and uniform lumpiness of coke. Fine coals contribute to the increase in coke size. According to the prototype, the addition of 5 wt.% Brown coal semicoke (BOD) to the components of the mixture gives a positive effect: a) increases the mechanical strength of coke by 2.2 wt.%; b) the abrasion of coke is reduced by 1.4 wt.%.

However, the known method has a significant drawback, since the presence of BOD in the charge (depleting additive) leads to a decrease in the coking process of the yield of non-volatile liquid compounds (NLC), which are responsible for the transition of the coking mass to a plastic state and its formation. In the prototype, the burst pressure will be higher compared to coking without thinning additives. The amount of NLF in the charge should be optimal, since the NLF actively interacts with particles of the emerging semicoke, adsorbing in its pores and cracks. Under optimal conditions, the zone of the ground plastic state is characterized by a minimum viscosity and maximum vapor and gas saturation. When introducing thinning additives (BOD or flaking coal of the OS grade) into the charge without compensating for the lack of NLF with the addition of liquid products like NLF (for example, heavy brown coal pyrolysis resins), the plastic mass will be characterized by increased viscosity and even greater vapor and gas saturation, which leads to an increase in the coking chamber bursting pressure, which is fraught with an emergency or premature failure of the coke oven refractory masonry. This phenomenon adversely affects the operating mode of coke ovens and leads to their premature wear.

The objective of the proposed technical solution is to expand the raw material base of coking and increase the yield of target coke with improved physical and mechanical characteristics.

This object is achieved by the fact that in the method of preparing for layer-by-layer coking of a charge containing products of thermal processing of brown coals, by grinding the components, including the exhaust additive, mixing and drying them with a heat carrier, into the initial charge containing a mixture of gas, gas fatty, fatty, coke and lean coals, additionally introduce a modifying additive in the form of pre-heat-treated brown coal tar high-speed pyrolysis of brown coals, and as a lean additive enter a lean repenting coal or its mixture with a "fatty additive" in the form of a second coke coal with the content of lean coal in the charge in the amount of 4.32-14.32 wt.%, and coal of the second coke in the amount of 6.09-13.09 wt.% .

The task is also achieved by the fact that 3-10 wt.% Of the exhaust additive in the form of OS6 coal, 3-7 wt.% Of the "fat" additive in the form of the second coke coal of the K ₂ and 3-6 wt.% Are introduced into the initial charge modifying additives. In addition, the task is achieved in that low-ash, low-sulfur Kansk-Achinsk brown coals or brown coals of Mongolia of various deposits or brown coals of other regions of similar quality are used to produce heat-treated brown coal of high-speed pyrolysis.

The technical effect of the proposed method is to obtain the target product with improved physico-chemical properties (increased strength and reduced abrasion) and with a high yield, as well as the expansion of the coking raw material base.

The proposed technical solution is new, has an inventive step and is industrially applicable.

Examples of the method.

Example 1. Coke the charge of the Zaporozhye Coke and Chemical Plant (ZKKhZ) in an experimental furnace made of refractory material, which is an airtight chamber 400 mm wide, 413 mm high and 365 mm long with side electric heating and riser for removal of volatile coking products. A single charge charge is 30 kg.

Grade composition of the charge (wt.%): Gas coal (G) 36.2; gas fatty (GF) 13.2; fat coal (W) 24.1; (the total content of coke (K) and second coke (K ₂ ) is 21.7; the content of K ₂ coal in the charge is 7%; lean coal (OS) 4.8; coal of K ₂ Donbass is characterized by the parameter y = 18.6; sulfur content of 2.6 wt.%; coal K ₂ Kuzbass contains 0.5% sulfur and is characterized by a parameter y = 8.7 mm Technical analysis of the mixture: ash ash on a dry mass of 7.4 wt.%; the yield of volatiles on a combustible mass 33 wt.%; total sulfur content per dry charge 1.83 wt.%;

Plastometric indicators of the charge: shrinkage (x) 41 mm; the thickness of the plastic layer (y) 17.5;

The specified charge is loaded into the experimental furnace at a temperature inside the furnace of 1000 ° C, the temperature of the side walls is maintained for 10 hours within 1250-1300 ° C. Upon reaching a temperature of 950 ° C in the axial plane of the coke cake, the coke is kept at this temperature for another 2 hours, after which it is discharged into the dry quenching chamber, where the coke is quenched for 4-5 hours without air. The coke yield is determined on a laboratory balance with an accuracy of ± 0.01 kg. Coke is successively sieved through sieves with openings of 80, 40, 25 and 10 mm. Then the superlattice products are weighed and the yield (wt.%) Of the fractions (mm)> 80 is determined; 80-40; 40-25; 25-10 and less than 10.

Coke abrasion tests were carried out in a snare drum (12.5 kg load) in accordance with GOST 8929-65.

The viscosity of the plastic mass was indirectly evaluated by the puncture force during coking of the experimental charges in an automated plastometric apparatus (GOST 1186-69). The experiments were carried out in the central laboratory of the Zaporizhzhya Coke and Chemical Plant, at the Department of Coal Chemical Production Technology of the St. Petersburg State Technological Institute and at the Novokuznetsk Center of the Eastern Coal Chemical Institute.

The compositions of the mixtures according to the present method, as well as the test results of the plastometric parameters of the mixture and physico-chemical parameters of the obtained cokes are given in table 1-3.

The remaining examples shown in Table 1 are carried out analogously to Example 1. To obtain modifying additives, brown coal was used from deposits in Russia and Mongolia. It is possible to use brown coals from the basins of other countries for the quality of the Kansko-Achinsky (Russia) basin close to the coals or the Baganuursky and Tugrugnuursky deposits of Mongolia (Mongolia).

In the inventive method for coking, the basic blends of the Zaporizhia Coke and Chemical Plant were used with the addition of flaked coal (OS6), a second coke (K ₂ ) and heat-treated heavy tar brown coal pyrolysis resin with the following characteristics:

1) OS6 coal with an ash content of 6.5 wt.%, With a release of volatile fuels of 17.1 wt.% And a moisture content of 2.8 wt.%.

2) coal K ₂ with an ash content of 6.8 wt.%, With a release of volatile fuels of 21.4 wt.%, With a working humidity of 2.7 wt.%.

3) Heat-treated (with the removal of 5.1 wt.% Of liquid and vapor-gas products from the initial total resins of high-speed pyrolysis) heavy resins of high-speed pyrolysis of brown coal had a boiling point of 270-272 ° C and were characterized by the following indicators:

a) Heat-treated resin of high-speed pyrolysis from Kansk-Achinsky brown coal of the Berezovsky deposit (TSVP KAU) - density 1250 kg / m ³ ; softening temperature 35.3 ° C; ash content of 1.97%, Conradson coking capacity of 32%; elemental composition (wt.% per combustible mass): C 81.3; H 5.9; N, 0.8; S 0.31; O 11.7.

Characteristics of heat-treated resins of high-speed pyrolysis of brown coals of Mongolia: a) Heat-treated resins of high-speed pyrolysis from Baganuur coals (TSVP BN): density at 20 ° С 1236 kg / m ³ ; softening temperature 34.9 ° C;

b) Heat-treated resin of high-speed pyrolysis from Tugrugnuur coal (TSVP TN): density at 20 ° C 1232 kg / m ³ ; softening temperature 34.6 ° C;

c) In Table 1, in addition to the plastometric indicators (x and y) of the base and the proposed blends, the values of the efforts (relative units) of the plastic dip during measurement of the thickness of the plastic layer when testing them in an automated plastometer are given.

When coking blends No. 2, 4-6 (table 1), the puncture force of the plastic mass is higher than that of typical blends used in industrial coking at the Zaporizhzhya Coke and Chemical Plant (ZKHZ), but it is lower than that of the prototype. Therefore, when coking all the claimed blends (table 1), the burst pressure in the coking chamber will be lower than that of the prototype, which will favorably affect the service life of coke ovens. The most comfortable coking conditions (according to the criterion of safe operation of coke ovens) are provided on blends No. 2, 7-11 (the minimum effort to puncture the plastic layer of the coke charge).

The price ratio for the coal grades used in the blends (according to the ZKHZ) is as follows: Donbass coals G: F: K: OS-1: 1.26: 1.36: 1.21; GZ coal of the Lviv-Volyn basin - 1.15, relative prices for Kuzbass coal (grades G and K ₂ ) 0.48; 0.58, respectively. The cheapest components of the proposed blends are lignite semi-coke (BOD) and heat-treated high-speed pyrolysis resin (TSVP) from the pilot plant of Tverskaya CHPP (0.36) with a basis equal to one (cost of gas coal from the Donetsk basin). This is due to the low price of brown coals of the Kansk-Achinsk basin, where mining is carried out by open pit mining at powerful coal mines. The higher cost of Donbass coal is associated with the low working capacity of industrial complex formations and with a greater depth of coal than Kuzbass.

Thus, it can be seen that it is advisable to use relatively cheap coals and additives in blends: G, K ₂ , OS6, TSVP. The use of brown coal semi-coke in the coking charges is also expedient, economically justified, and this option was proposed in our prototype.

However, it is not advisable to increase the content of gas coals in the coking charges in comparison with the optimum, since this will lead to a decrease in the yield of gross coke and a deterioration in its quality (mechanical strength).

Therefore, it is advisable to modernize the compositions of the initial coking charges by using individual additives of BOD, K ₂ , OS6, TSVP coals or various combinations thereof.

From table 2 it is seen that commodity coke from the claimed charge compared to industrial coking of the charge ZKHZ characterized by an increase in mechanical strength (yield class M25) to 2.7% and a decrease in abrasion (yield class M10) to 2.9%. Commodity coke is characterized by these indicators also higher rates compared to the prototype.

The most favorable coking conditions (pressure bursting) are observed when using the inventive charge No. 7-11. Under these conditions, higher yields are achieved for the yield of coke classes +80, 80-40, 40, 25 (Table 3). Compared to industrial coking of the ZKKhZ blend, the abrasion of coke (class minus 10) is reduced by 2.5-2.9 wt.%

In addition, according to the claimed method, modified mixtures will be cheaper due to the involvement of less expensive and less scarce grades of OS6, K ₂ coal and modifying additives (heat-treated resins of high-speed pyrolysis of brown coal) in their composition.

The total beneficial effect of the invention is to expand the raw material base of coking, increase the yield of bulk coke and improve its physical and mechanical properties (increased strength and reduced abrasion).

Table 1 The thickness of the plastic layer (y) and shrinkage (x) and the puncture force (p) of the base and claimed charge coking No. p / p The composition of the charge, wt.% x mm y mm P relates. units one Base charge ZKHZ 33 22 0.16 2 Charge + 10% TSVP (KAU) 35 26 0.10 3 Charge + 10% BOD (KAU) 28 19 0.23 four Charge + 10% BOD (BN) + 3% TSVP (BN) thirty eighteen 0.20 5 Charge + 10% of OS6 coal 28 19 0.23 6 Charge + 10% of OS6 coal + 3% TSVP (KAU) 29th twenty 0.17 7 Charge + 10% of OS6 coal + 6% of TSVP (TN) 32 23 0.15 8 Charge + 10% of OS6 coal + 6% TSVP (KAU) 32 22 0.14 9 Charge + 10% of OS6 coal + 6% of TSVP (BN) 32 23 0.14 10 The mixture + 7% coal K2 + 3% coal OS6 + 3% TSVP (KAU) 31 24 0.13 eleven Charge + 7% of coal OS6 + 3% of coal K ₂ + 6% TSVP (BN) 33 22 0.16

table 2 Coke yield and strength (%) ** No. p / p The composition of the charge, wt.% Mechanical strength,% Coke yield,% M25 M10 7 The charge ZKHZ + 10% coal OS6 + 6% TSVP (TN) 88.4 7.5 79.5 8 ZKHZ charge + 10% of OS6 coal + 6% TSVP (KAU) 88.4 7.4 79,4 9 The charge ZKHZ + 10% coal OS6 + 6% TSVP (BN) 88.4 7.5 79.5 10 ZKHZ charge + 7% K2 coal + 3% OS6 coal + 3% TSVP (KAU) 88.6 7.1 79,4 eleven ZKHZ charge + 7% of OS6 coal + 3% of K2 coal + 6% of TSVP (BN) 88.7 7.4 79.7 12 The charge ZKHZ + 5% BOD (KAU) 87.1 6.6 78,2 13 The charge ZKHZ + 10% BOD (KAU) 88.2 9.2 78.3 fourteen Charge ZKHZ 86 10 78 ** The moisture content of the mixture of 2.3-2.7%

Table 3 The sieve composition of coke from the inventive and base charge No. p / p Content dobovak to the basic charge ZKHZ, wt.% Coke yield by size classes (mm), wt.% OS6 K ₂ TSVP +80 80-40 40-25 25-10 -10 7 10 - 6 (VT) 4,5 fifty 29.4 9.6 7.5 8 10 - 6 (KAU) 4.6 50.1 28.0 9.9 7.4 9 10 - 6 (BN) 4,5 fifty 28.1 9.9 7.5 10 3 7 3 (KAU) 4.8 51.5 28.3 8.4 7.1 eleven 7 3 6 (BN) 5.7 51.3 28 9.6 7.4 Base charge ZKHZ 0 0 0 2,4 49 28,2 10,4 10

Claims (3)

1. A method of preparing for layer-by-layer coking of a charge containing products of thermal processing of brown coals by grinding components, including an exhaust agent, mixing and drying with a heat carrier, characterized in that the initial charge containing a mixture of gas, gas, fatty, fatty, coke and sintering coals, a modifying additive is additionally introduced in the form of a pre-heat-treated brown coal tar of high-speed pyrolysis of brown coals, as a sludge additive is introduced a sintering coal or its a mixture with a "fatty" additive in the form of second coke coal with the content of leaning coals in the charge in the amount of 4.32-14.32 wt.%, and the second coke coal in the amount of 6.09-13.09 wt.%. 2. The method according to claim 1, characterized in that 3-10 wt.% Of an exhaustive additive, 3-7 wt.% Of a "fat" additive and 3-6 wt.% Of a modifying additive are introduced into the initial charge. 3. The method according to claim 1 or 2, characterized in that to obtain a heat-treated brown coal tar of high-speed pyrolysis, Kansk-Achinsk brown coals or brown coals of Mongolia from various deposits are used.