Environmental & Energy Conservation

Great concern is paid to the energy consumption reduction in the coking process and environment improvement, and a large amount of exploration has been made. Japan is credited for developing the coal moisture control process. The heat transfer oil and thermal medium of steam are respectively utilized in the 1st and 2nd generation to directly and indirectly regulate moisture of coal material. This method indirectly wasted external heat supply like steam with complicated equipment, large investment and high operation cost. In order to improve granularity of coal charge to make it more well-distributed, former Soviet Union developed pneumatic separating technology. But it has this only effect and little applications. The pretreatment technology of granularity classification and moisture control to coking coal in coal preparation system is one of the advanced technologies in coking industry.

MIPL & Jiangsu Zhongxian Group Co. Ltd., which is devoted to environmental protection with independent intellectual property rights, has been cooperating with international first-class R&D Institutions and coking factories on areas of coal moisture control and classification & separating technologies. The group owns advanced moisture control and classification & separation technologies and equipments. We can set up appropriate process flow and equipments of moisture control and classification & separation technologies according to requirements of clients to optimize economic, environmental and social benefits.

Technology and facilities:
2.1 Technology :The coal moisture control and classification & separating technologies are applied to deliver coking coal to moisture classification apparatus through feeding system. The coal material is fluidized by remaining heat of flue waste gas of 180°c—220°c in coke oven as heat source and power supply and then heat circulation to control moisture is conducted. The coal material will be classified and separated according to granularity grade. After moisture control and separation, the coal material of fine granule less than 3mm will be conveyed to coal tower through transportation system and coal material of coarse granule more than 3mm will be feeded into pulverizer to be pulverized and then conveyed to coal tower. The exhaust gas out of moist control will be gathered at the main pipe and dust-removed by dust remover and then discharged into the air. The coal dust collected from each dust remover will be formed through forming machine and then conveyed to coal tower.

2.2 Major facilities : Major facilities coal material transportation system, feeding & discharging system, moisture control classification apparatus, exhaust gas induced fan, dust removing system, coal dust forming apparatus and system of monitoring, testing and controlling etc.

2.3 Characteristics :

1. In the process, the waste flue gas in coke oven is taken as the heat source for adjustment of coking coal moisture and power supply of coal material classification & separation, that is, make full use of plenty of low-heat complementary energy in the coke-oven plant without the external heat supply, and cancel the external heat supply required in the traditional process.
2. The moisture control classification apparatus selected in the process function as adjustment of coking coal moisture and its classification and separation. In the same moisture control classification apparatus, it meets the requirement of coking coal moisture control and granularity classification.
3. The process can realize the granularity classification of coking coal and make granularity of coal material more well-distributed. Therefore, the coking coal with coarse granule can be pulverized to make inert constituents and high ash percentage components pulverized to appropriate degree of fineness and avoid the over grinding of coking coal of fine granule.
4. Systematically set up technical and environmental dust removal facilities for the dust purification in each dust-entrainment points, thus there is no air and environment pollution. Then send the collected coal dust after the forming treatment.
5. Systematically apply the centralized operation and control model with high automation, stable production and reliable operation, which makes the unmanned site operation true. Optimize collecting control of flue gas waste in coke oven to ensure no effect on the coke oven production.
6. This simple system process integrates feeding, classification & separation, drying and discharging. It occupies small area and has reliable equipment with strong processing power and adaptation to production.

2.4 Effect of the project :

1. The implementation of CMCC technology boasts the distinct effect of energy conservation.
   • Make full use of plenty of low-heat complementary energy of flue gas in the coke oven in the coke-oven plant.
   • Reduce the moisture content of coking coal so as to make the energy consumption of heating coal gas in the coking process dropped (about evaporation energy consumption of appropriate water in the coking process).
   • Only make the coking coal with coarse granule grinded, thus the workload of pulverizer in the coal preparation workshop is reduced so as to save 30% electricity power consumption..
2. The water content of coking coal can be reduced by 4% to 6%. It can reduce the discharge rate of coking sewage. The relevant water needn't to be put into treatment process for coking sewage. The control and stabilization of moisture within coal material can lead to stable operation of coke oven and prolonged useful life of it.
3. The implementation of CMCC obviously improves the thermal stability of coking coal, improves indices of coking coal’s quality and increases coke strength and ash content of coking coal.
4. With bulk density of coking coal increased and distillation period shortened, the production capacity of coke oven can be improved by 8%-10%.
5. While the quality of coking coal is kept the same or improved slightly, the weak-coking coal can be used more of 8%-10%.
6. Technology of processing CMCC by waste flue gas in coke oven can realize recycling of waste heat energy. This technology is an important constitutes for coking industry to develop circular economy and reduces greenhouse effect and 36kg carbon dioxide per ton will be less discharged.

3.1 Specifications
The capacity of the oven corollary equipment is 1200000t/a
Coal blending is 1800000t/a - 10% water content
Capacity of CMCC is 300t/h
Equipment working hour per day: about 18 hours
Equipment working days per year: 330days


Cost and benefit
3.2 Investment cost
The scope of this project in investment estimation are major facilities for CMCC, flat support with steel structure, power supply and distribution, water supply and drainage, General Layout and Transportation in the regime of CMCC, other costs about installation and testing of the project and so on.

*Note: We are responsible for designation of the general layout and distribution of the CMCC, the manufacture and installation of the major facilities and flat structure with steel structure, while the civil construction is completed by customer.

3.2 Compilation basis

1. The installation of the project is as per the production process; there is no gap in production investment in principle and the calculation is on the basis of the physical project.
2. Construction installation engineering to co-ordinate with the standards of comprehensive budget quota and cost of construction installation project in Province, part is coordinated with the similar projects indexes.
3. Price : The validity period of the offer is one month and the preparation cost is 5% of the direct project cost and other costs

3.4. Period of construction and reaching production target
Our project is only one time design and construction, the period of the installation and testing is three months and it can reach production target after putting on production.

3.5. Operation analysis
Our project can classify the coal as per granularity requirement by the coke oven gas tunnel waste gas of chimney in the fluidized bed and remove some water as to optimize coal granularity and control coal moisture. The capacity of the system is 300t/hour. In the process, the coal, water, electricity, compressed air, waste heat of coke oven tunnel gas and so on will be consume.

3.6. Operation cost
As per the scale of1200000t/a capacity of coke oven.
The consumption energy and working fluid of this project equal to consume 3636.05ton standard coal


3.7. Project benefit analysis
The loaded coal moisture can be reduced from 10% to 6.5%, the time of coking can reduce 4%, phenol-cyanogen waste-water can be reduced 3%, and the coke oven capacity can be improved by 7%, so we can increase production 81500ton per year.


4. The condition needed for CMCC
The date provided by us:

1. Engineering regional plan graph: 1:1000
2. The existing graph of new or old one in recent years: 1:500;
3. Designation graph in industrial area and the old plant
4. The existing architecture and construction graph of coal blending and pulverizer system, and the original dedusting engineering graph.
5. Belt conveyor for going up to coal tower
6. Coke oven chimney, plan and elevation graph of chimney flue, main flue turning plate valve and its installation graph.
7. Corollary coke oven specification, capacity, moist coal consumption per year, coal preparation matching facilities, the number of pulverizer and belt conveyer, their capacity, and so on.
8. Moist coal data: the moisture content(%), granularity, blending coal heap density (kg/m3), specific heat capacity of coal kJ/kg.
9. Waste gas data: specific heat capacity kJ/kg. Temperature, humidity, oxygen content, waste gas capacity of single chimney flue, main chimney flue suction range in the base of chimney
10. Dynamic medium contact of engineering water, electricity, compressed air, nitrogen and the range of dedusting.
    • Normal compressed air: pressure and fluctuation range, dew point, dust content, surplus and connecting point position.
    • Purified compressed air: pressure and fluctuation range, dew point, dust content, surplus and connecting point position.
    • Nitrogen: pressure and fluctuation range, purity degree, surplus and connecting point position.
    • Voltage grade: the requirement of selection type of low voltage cabinet, computerized integrated protection, PLC, frequency converter;
11. Meteorology data in plant area
12. Geological data in plant area
13. Flood data in plant area
14. Virescence data in plant area
15. Requirement of control

With the improvement in Iron smelting technology the coke consumption in Blast furnace is decreasing year by year, resulting in lower calorific value of Blast-furnace gas. If only Blast-furnace gas is burnt in air heating furnace, the blast temperature can reach upto 1000 to 1050 ºC, which can not meet the requirement of high blast temperature.

In order to increase the blast temperature, lots of measures have been taken in China, for example, mixed burn of some coke-oven gas of high calorific value, pre-heat the air and gas by flue gas heat in the air heating furnace. Due to general shortage of coke-oven gas with high calorific value in most iron & steel plants and the low temperature of waste gas in flue pipe, where even with a separate heat pipe heat exchanger, the air and gas to be blasted into the hot air furnace can be reheated to 150 to 170 ºC only. Some other heat source should be developed to pre-heat the air and gas to the required 250 to 450 ºC respectively if we want to realize a high temperature at 1200 ºC to 1250 ºC with only blast-furnace gas burned in air heating furnace. Under these conditions, the technology of double pre-heating device (or sectional type) with additional burning furnace has been developed.

Operating principle:
The system is made of additional burning furnace, tube type air pre-heating device, gas pre-heating device (sectional high –temperature air preheater), combustion fan, flue gas induced draft fan etc.

The pre-heating device is of tube-type heat exchanger that induces the flue gas heat in Air heating furnace into the mixing box of burning furnace by high temperature induced draft fan to mix with the high temperature flue gas in the burning furnace. This helps to get mixed flue gas at 500 to 600 ºC which further enters into the air and gas pre-heating devices separately. After heat exchange, the air and gases are heated to 250-300º C. The sectional pre-heating device is of tube-type heat exchanger that pre-heat the air and gas to 150-170º C by flue gas in air heating furnace firstly, then it induces the flue gas heat in air heating furnace into the mixing box of burning furnace by high temperature induced draft fan to mix with the high temperature flue gas in the burning furnace to get mixed flue gas at 550-700º C, and then pre-heat the combustion air which has been pre-heated to 150-170ºC to 450ºC again by such mixed flue gas, and finally, the air and gases are heated to 450ºC and 170ºC respectively.

The pre-heated air and gas further enters into the air heating furnace for burning. Due to the increased physical heat of air and gas, the hot blast temperature can also be increased. It is analyzed according to the result of thermodynamics that the adoption of “double pre-heating systems with additional burning device” can guarantee increase in the hot blast temperature by 180-200º C, so as to greatly reduce the Coke Ratio and increase coal injection and output.

1. It can be used to treat the dust in iron and steel plants, various dust, sludge, iron oxide scale and pickling residue, etc. in agglomeration plants, iron mills, steel works and rolling mills. Valuable metals such as Zn and Pb, etc. can be collected in the process for metal iron recovery.
2. It can be used to directly produce iron via. reduction, produce high-quality metallized pellets by the raw material of iron ore concentrate or high-grade ore powder for blast furnace and electric furnace or used as the cooling agent for rotary furnace.

Advantages

1. Optimized iron making operation
   The rotary furnace as the recovery station is a relatively independent flow in an iron and steel plant, it can be used to treat various dust by a centralized mode and supply stable and uniformly composite products to the blast furnace, the optimized operation in the iron making system has totally realized the self-digestion of dust in the iron and steel plant.
2. Zinc recovery
   More than 90% Zn in the dust can be recovered and crude ZnO dust that the ZnO content is 80% above can be obtained.
3. No secondary pollution
   The rotary furnace is a sealed system with clean flue gas and micro negative pressure operation, and there is seldom discharge in the whole process.
4. Interconnected to the existing flow
   The technique of rotary furnace is highly independent and seldom conflict against the existing flow.
5. Multifunction
   Valuable metals can be recovered in dust treatment; iron can be directly produced via reduction with the raw material of high-quality iron ore concentrate powder

With the high development of iron and steel industry, the techniques for coking, gas purification and recovery have also been changed quickly, the large scale modernization of coke oven plants at present has clearly shown that the techniques for coal coking and the recovery of chemical products are still playing an important role in the future production of iron and steel.

Technical flow for gas purification and recovery
Raw gas is brought up into the gas collecting pipe from the charging chamber, circulatory ammonia water is used for spraying to cool down the gas and separate the tar and ammonia water out; the gas is then brought via the suction pipe to the primary cooler and then the air blower in the recovery workshop, after the gas is cooled down and treated by various absorbents, chemical products including tar, ammonia, crude benzol and so on are extracted, and the purified gas from the coke oven is usually sent back to the coke oven for heating or used as the fuel for other metallurgical furnaces, or furthermore used as the raw gas for ammonia synthesis or the civil urban gas.

Flow of traditional gas purification:
1 Primary cooling - 2 Gas supply - 3 Electric capture - 4 Pre-cooling (preliminary naphthalene depriving) - 5 Desulphurization - 6 Thiamine - 7 Naphthalene final cool washing - 8 Debenzolization - 9 Gas purified

The air blower sends gas at 50°C~60°C, which is cooled to 30°C~32°C after the cooling and naphthalene removal made by remaining Ammonia and condensing in the pre-cooling tower, after which the naphthalene content should be less than 300mg/m³. Then it goes to the desulfurization section at the bottom of the primary desulfurization regenerating tower to countercurrent contact the desulfurization solution sprayed from the top tower; under the reaction of catalyst, the sulfureted hydrogen and hydrogen cyanide in the gas get absorbed in the desulfurization solution which is further pumped onto the regeneration section of the tower by the recycle pump through the wet seal in the bottom of the tower to contact with air by self-priming injector for catalytic oxidation regeneration. The regenerated liquid flows into the desulfurization section for rotative spray by means of the liquid level regulator. And then the coke oven-gas after purification in the primary sulfurization system will goes to the second and third class desulfurization purification system (same class in the process), so that the sulfurated hydrogen content in the gas becomes less than 20mg/m³. After the desulfurization, the gas goes to the ammonium sulfate section. The sulfur foam spills over the regeneration section of desulfurization tower self-flows into the concentrating groove and the sulfur foam concentrate is sent into the sulfur melting furnace by the sulfur foam pump. Then the molten sulfur after smelting flows into the cooler pan and after natural cooling, we get the product sulphur.

It describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the concentration of such contaminants so the water becomes fit for its desired end-use. One such use is returning water that has been used back into the natural environment without adverse ecological impact. The processes involved in treating water for drinking purpose may be solids separation using physical such as settling and filtration, chemical such as disinfection and coagulation. We can provide full water treatment solution from China.