ISSN 1068�364X, Coke and Chemistry, 2014, Vol. 57, No. 2, pp. 51–54. © Allerton Press, Inc., 2014.Original Russian Text © S.N. Dyakov, D.A. Aredakov, D. Iovanovich, 2014, published in Koks i Khimiya, 2014, No. 2, pp. 31–34.

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Coke plants are significant sources of toxic emis�sions. Russia’s coke plants produce far more emissionsthan their counterparts in Western Europe, Japan, andthe United States.

At present, in the developed world, no coke batterycan go into operation without a system for dust�freecoke discharge from the coke ovens [1].

Large quantities of dust and gas are released at cokedischarge from coke ovens and pollute the atmo�sphere. The dust is formed as a result of contactbetween the coke and the air and the creation of adirectional flux that drives upward the small particlesformed in the disintegration of the coke cake.

In the past, cyclones and wet dust traps with scrub�bers were mainly used to remove dust from coke�plantemissions. However, they were ineffective and did notmeet environmental requirements. Wet cleaning isenergy�intensive, consumes considerable quantities ofwater, and requires slurry treatment. Its use is cur�rently being discontinued [2]. The chosen replace�ment is efficient and reliable dust removal by means ofbag filters, with pulsed regeneration [3].

To meet more stringent environmental require�ments on coke plants, equipment must be modernizedand reconstructed so as to prevent emissions of sus�pended particles and aerosols.

Note that effective means of localizing the emis�sions in coke discharge have only been developed forthe coke side of the battery: hoods on the door�open�ing machines; and stationary and local dust�free coke�discharge equipment with wet and dry purification [4].Practically no attention has been paid to the machineside.

Until now, the emissions in predischarge removaland cleaning of the furnace�chamber doors, utiliza�tion of the coke spills, cleaning of the sealing surfaces,and installation of the doors have been regarded as partof the total emissions in coke discharge. Measurementof these unorganized emissions was impossible.

As part of the plant�wide program for reducingemissions at OAO Koks, it has been decided to equipthe coke ejectors at coke battery 3 designed and man�ufactured by GOSA�FOM (project 07018) with a sys�tem for aspiration and purification of the emissions onthe machine side formed in basic furnace operations(predischarge removal and cleaning of the furnace�chamber doors, utilization of the coke spills, cleaningof the sealing surfaces, and installation of the doors).

This system was designed and manufactured byGOSA�FOM in accordance with OAO Koks specifica�tions and installed by plant specialists at coke ejector 4.

This system permits the determination of the emis�sions in removal of the doors, coke discharge, andother door�management operations on the machineside, without folding them into the total emissions incoke discharge.

The dust trap includes two hoods, two air lines thatconverge to a single line, a dust bunker, a filter unit,and a fan unit. The first hood is above the pressureunit. It may be moved toward the front of the batteryby means of a hydraulic drive so as to maximize dustcapture (Fig. 1a). The second hood is rigidly attachedabove the point where the doors are cleaned (Fig. 1b).

The dust–gas mixture travels along the air linesfrom the hoods to the bunker with a filter unit (Fig. 2).An extinguisher at the bunker input prevents the pen�etration of an open flame to the filter surface. The air

Dust�Free Coke Discharge on the Machine Side of Coke OvensS. N. Dyakova, D. A. Aredakovb, and D. Iovanovichc

aOAO Tulachermet, Tula, Russiae�mail: info@tulachermet.ru

bOAO Koks, Kemerovo, Russiae�mail: eak@kem.metholding.ru

cGOSA FOM, Smederevska Palanka, Serbiae�mail: gfom.ing@eunet.ru

Received January 9, 2014

Abstract—Operational experience with a system for dust�free coke discharge is outlined.

Keywords: coke battery, dust emissions, coke ejector, aspiration, bag filters, efficiency

DOI: 10.3103/S1068364X14020057

COKE

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lines are maintained at very low pressure by a fan unit,which includes a 45�kW electric motor (speed 1470 rpm)and a 30000�m3/h fan.

The filter unit includes 135 FRKI�180 bag filters,made of material that is stable up to 200°C.

The filters are cleaned automatically by means ofcompressed air flowing in the opposite direction to thedirty air. The compressed air is supplied by means offorce pumps made of aluminum, with rubber seals toprevent air loss. The compressed air is supplied to thefilter through electromagnetically controlled mem�brane valves. The bunker is emptied manually, and thetrapped dust is transported to its point of use.

The system operates automatically. Before remov�ing the door, the hood is moved to the pressure unit atthe battery front. At the same time, the fan is switchedon and continues to operate until the door is reat�tached. The dust–gas mixture is sent through the airline to bag filters. When the winch for removing thedoor is returned to its initial position, the hood ismoved back from its position near the front of the bat�tery and, after 30 s, the fan is switched off. Duringoperation, the filters are cleaned once every 30 s.

The table presents 2012 data for the dust content ofthe gases before and beyond the filter from the accred�ited plant laboratory.

The unorganized dust–gas emissions formed onthe machine side of the coke battery are partially cap�tured by the two hoods of the trap and purified at thebag filter. The remainder is released to the atmosphere.

(a) (b)

Fig. 1. Dust emissions in coke discharge and other furnace operations on the machine side.

910 11

12 1

2

35

6

7

8

4

Fig. 2. Dust trap at the coke ejector: (1) purified�air out�put; (2) suction pump; (3) valve; (4) coke�dust discharge;(5) coke dust; (6) bag filter; (7) unpurified air from cokedischarge; (8) unpurified air from door cleaning; (9) airintake valve; (10) receiver; (11) diaphragm valve; (12) elec�tromagnetic valve.

COKE AND CHEMISTRY Vol. 57 No. 2 2014

DUST�FREE COKE DISCHARGE ON THE MACHINE SIDE 53

The ratio of these two components determines thedegree of localization

η1 = qorg/qn,

where qorg is the total volume of gas captured by thehood; and qn is the total volume of emitted gases.

According to expert estimates, the degree of local�ization is ~60%. That permits the determination of theinitial quantity of emitted dust in door cleaning andcoke discharge on the machine side

gun = gorg/η1 = 1.148/0.6 = 1.913 g/s.

Here gun is the initial quantity of dust, g/s; gorg is thequantity of dust at the filter, g/s; η1 is the degree oflocalization.

The total dust emission in door cleaning and cokedischarge on the machine side may be determined onthe basis that emission at a rate of 1.913 g/s continuesfor 2–3 min. Taking the mean value of 2.5 min, wemay determine the total dust emission g20 (g) in aperiod of 20 min (two operations)

g20 = 1.913 × 60 × 2.5 × 2 = 574 g.

The total quantity of dust emitted in door manipu�lation may be compared with the total quantity of dustreleased in coke discharge on the basis of OAO Koksdata. In 20 min, corresponding to no more than twooperations, the dust emission due to coke dischargealone is

G20 = 799.16 × 2 = 1598.32 g.

Then the ratio of the quantity of dust emitted indoor manipulation to the total quantity of dustreleased in coke discharge takes the form

K = 574/(1598.32 + 574) = 0.26.

Thus, the ratio of the quantity of dust emitted in doormanipulation to the total quantity of dust released incoke discharge at battery 3 is 0.26 : 1 or 26%.

The efficiency of the system for dust�free coke dis�charge in terms of reducing the atmospheric emissionsof dust may be regarded as the efficiency of a two�stagesystem: the first stage is characterized by the inverse ofthe localization of the emission (showing how muchdust is not drawn into the hood), and the second by thedegree of purification in the bag filter.

The efficiency of the system for dust�free coke dis�charge may be expressed in terms of the decrease indust emissions during door cleaning and coke dis�charge, as follows

N = 1 – (1 – n1)(1 – n2)

= 1 – (1 – 0.60)(1 – 0.909) = 0.96 or 96%,

where n1 is the degree of localization of the emissions,which is 60% (according to OAO VUKhIN recom�mendations); n2 is the degree of purification in the bag

filter, which is 90.9% (according to laboratory datafrom OAO Koks).

The trapped dust is used for production processes.Benefits of the system for dust�free coke dischargeinclude the following:

—96% reduction in coke�dust emissions from themachine side;

—improvement in working conditions;

—reduction in pollutant emissions to 1.6 kg/t ofcoke, in contrast to the mean value of 5–6 kg/t forRussian coke plants [5].

Mean bag�filter data

Dust concentration, g/m3

Dust content in flux, g/s

Degree of purifi�cation, %

ahead of filter

beyond filter

ahead of filter

beyond filter

0.374 0.026 1.148 0.104 90.9

Fig. 3. System for dust�free coke discharge at coke battery 6.

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Currently, the best approach to improving workingconditions and reducing environmental impact is tointroduce a system on the machine side for dust trap�ping during the predischarge removal of the furnace�chamber doors, coke discharge, utilization of the cokespills, cleaning of the sealing surfaces, and installationof the doors.

REFERENCES

1. Tikhov, S.D., Dudarev, B.G., and Kolmakov, N.G.,Dust�free coke discharge: Approaches and efficiency,Koks Khim., 2004, no. 2, pp. 14–15.

2. Shvets, M.N., Stalinskii, D.V., and Pirogov, A.Yu., Drycleaning of coke�plant emissions in bag filters, CokeChem., 2007, vol. 50, no. 11, pp. 356–358.

3. Shvets, M.N., Trembach, T.F., Stalinskii, D.V., andPirogov, A.Yu., Using bag filters for coke�plant emis�sions, Ekol. Prom., 2006, no. 1, pp. 8–11.

4. Kaliberda, N.S., System for dust�free coke discharge,Koks Khim., 2004, no. 3, pp. 37–40.

5. Sukhorukov, V.I., Stakheev, S.G., Stefanenko, V.T., andKukolev, Ya.B., Localization and neutralization ofcoke�plant emissions, Koks Khim., 2006, no. 3, pp. 54–57.

Translated by Bernard Gilbert