Wuhan P&G Environmental Engineering Technology Co., Ltd. as an environmental protection high-tech enterprise, has been committed to the development and implementation of energy saving and emission reduction technology in the blast furnace production process, and has also achieved outstanding results. From 2006 to 2012, Wuhan P&G has completed the construction and renovation of all 7 blast-furnace slag treatment systems, including 1A1B# blast furnace (slag pool method), 2# blast furnace (WHBJ method), 3#4#6# blast furnace (Minte method), and 5# blast furnace (Jiahang method). The focus is also on solving the problem of fine slag removal in slag water and increasing cooling facilities. The three aspects of zero emission system won the third prize of Guangxi Science and Technology Progress in 2009 and the first prize of Liuzhou City and Liusteel Group. At the end of 2016, Wuhan P&G EPC general contract implemented the transformation of the slag treatment system of the second 2600m3 blast furnace in Xuangang, which provided urban heating after the heat exchange of slag water and waste heat, and achieved good economic and social benefits. From 2019 to 2021, EPC successively contracted the slag treatment system of 2 3800m3 blast furnaces in Guangxi Fangchenggang Iron and Steel Base Project and 1 2000m3 blast furnace in Liugang Zhongjin Stainless Steel Company.

The WHBJ slag treatment system developed by Wuhan P&G can exclusively treat the slag content of blast-furnace slag water in the whole industry to less than 2000mg/l, which is only equivalent to about 1.0% of the traditional Inbar slag treatment process, creating conditions for the slag treatment system to reduce operating costs and reliable heat transfer of blast-furnace slag water.

 

 

 

 

　　WHBJ method rotary drum self-cleaning super clean blast-furnace slag water treatment system

At present, various water-quenched slag treatment processes of blast furnace generally have the following problems in production, such as: slag system equipment and pipeline wear, short life, serious slag formation blockage, severe leakage, frequent maintenance, low system guarantee, high production cost; As well as steam emission is not ideal, environmental pollution is serious, operation energy consumption is high, can not operate normally and so on. The root cause is that the content of fine slag in the slag water is large, and the fine slag can not be effectively removed.

In view of the above phenomenon, Wuhan Procter & Gamble Environmental Engineering Technology Co., LTD., in the design process of Liugang 2# blast furnace, boldly abandoned and deeply optimized the traditional Leng Ba process water slag system, cancelled the traditional Inba method of the pump house hot pool design and recycling pump process. Innovated and developed a new technology of "combined cone sedimentation tank fine slag precipitation + lifting fine slag mechanical separation", thus forming a new process of self-cleaning super clean slag water treatment by WHBJ method with completely independent intellectual property rights, which can be applied to Inba hub.

After nearly ten years of operation test, WHBJ self-cleaning super clean slag treatment system has achieved great success and good results in the use of Liugang No. 2 blast furnace. The slag content of slag water is only ~ 1.2% of the traditional Inbaffa slag treatment system, the circulating water quality has been greatly improved, the equipment failure rate, maintenance and maintenance costs have been greatly reduced, and the clean production of the slag water system has been realized, and the system operation rate has reached 100%. Except for the replacement of the hub filter and the gas extraction cone, no major equipment has been damaged. The spare parts cost of the whole slag treatment system for three years is only ~ 200,000, and the spare parts and maintenance cost is only 1% of the traditional Inbar method. The slag treatment system completely realizes zero discharge, and realizes the use of coking advanced treatment wastewater to completely replace new water supplement. It is estimated that the operation power consumption after putting into operation is more than 2/3 of the traditional Inbar method, the annual power saving is 1082.9×10 kW.h, and the annual production and operation cost saving is more than 12 million yuan.

WHBJ self-cleaning super clean slag water process made up for the large amount of fine slag in the slag water of Baer process and the adverse effects of fine slag on the slag treatment system, which is a major breakthrough in the blast furnace slag treatment process. WHBJ method self-cleaning super clean slag treatment system fine slag treatment effect is good, excellent water quality, high degree of automation, stable operation of equipment, high guarantee, energy saving and environmental protection, maintenance and spare parts costs significantly reduced, low investment and operating costs, a number of innovative technologies have created the first slag treatment process, has achieved great success, It is a revolutionary technological advance of blast-furnace slag treatment process in metallurgical industry, which brings environmental improvement and huge economic benefits to blast furnace ironmaking production, and also creates better conditions for the utilization of residual heat from blast furnace slag water.

WHBJ self-cleaning super clean slag treatment system can also be applied in Jiahang process, Minter process and other slag treatment processes, in which the deep-water quenching steam centralized discharge technology can also be applied to filter filter slag treatment process.

 

　　The advantages of WHBJ self-cleaning super clean blast-furnace slag water treatment system

　　1, innovative "Combined cone sedimentation tank fine slag precipitation technology and its modular design", compact layout, small footprint, and can be perfectly combined with Inbar granulator/drum/belt conveyor/lifting pump room. The combined cone sedimentation tank can control the series or parallel operation of any state, and realize the slag-water flow of multi-range and long flow path, greatly improve the sedimentation effect of fine slag, and improve the operation guarantee degree of the system.

2, the innovative "lifting mechanical separation technology of fine slag", to achieve high concentration extraction and efficient dehydration separation of fine slag, and complete the perfect combination with the combined sedimentation tank and Inba belt layout, the fine slag extracted from the slag water system can be directly transported by Inba belt. The slag content of slag water in WHBJ process is only about 2000mg/l, which is equivalent to 1.2% of the traditional Inba process. The cost of spare parts in three years of operation is only about 200,000 yuan, equivalent to 1.0% of the traditional Inbaffa slag treatment process.

3. The innovative design of the process makes the cooling and pelleting pump group realize the dual use and one backup of the Inbar process to the one use and two backup of the WHBJ process, combined with the application of frequency conversion technology, the operating power consumption of the slag water system is greatly reduced, and the comprehensive power saving is more than 2/3 (annual power saving of 1082.9×104 kW·h).

4, slag water cooling using patented technology of hollow cooling tower and trough free hanging slag hollow cooling tower water distribution patent, the cooling water distribution system is completely free of slag accumulation and slag hanging phenomenon, and the summer high temperature slag water temperature can be reduced to 40℃ below.

5, the innovative "deep-water quenching steam centralized discharge technology", to achieve the slag in the granulated tower full release of heat and centralized discharge of steam, furnace and slag pond and other parts in the winter low pressure environment is basically no steam discharge, eliminating environmental pollution, improve the quality of water slag.

6, the main equipment such as water pump, inba drum and belt machine adopt frequency conversion speed regulation, automatically realize low frequency start and speed regulation, and the frequency reduction and power-saving operation of the slag clearance; The main valves are controlled by hydraulic centralization; The whole system is highly automated, saving labor and production costs.

7. The collection tank collects and regulates the water volume of the system, plays a role of zero discharge and scum interception, and improves the operation guarantee degree. The fine slag precipitation is mainly completed in the cone sedimentation tank (the collection tank only catches the slag once every 3 months).

8. The two slag systems in the south and north can realize the transfer of slag water, and the slag water system and the slag water in the slag field can realize complete reuse and zero discharge, and improve the utilization rate of water resources.

9, due to the great improvement of slag water quality, the new blast furnace project in the future to adopt WHBJ process, external slag water pipe can be replaced by ordinary thick wall steel pipe wear-resistant alloy pipe, investment costs can be greatly reduced.

 

　　WHBJ blast furnace granulated steam waste heat recovery desulfurization and white elimination integration technology

1. Art

Process flow: blast furnace slag water granulation → granulation tower steam collection → primary cloud dynamic cyclone atomization → secondary cyclone atomization spray → Granulation fan pressurization → chimney white discharge.

According to the environmental protection requirements of desulfurization flue gas whitening: when the saturated wet smoke vapor temperature is reduced to ≤48℃ in summer  ≤45℃ in winter, basically no white smoke can be seen. In this project, the temperature of smoke vapor is reduced to ≤45℃ in summer / ≤40℃ in winter, and the whitening effect of smoke is fully guaranteed. Annual water saving of 810,000 tons, recovery of steam waste heat 99.5MW.

2. Characteristics and significance

Low operating cost, the use of blast furnace slag water and the original system for waste heat utilization desulfurization and elimination of white, no additional water treatment and cooling operating costs; Using the upper space of the granulated tower to complete the whitening function, without changing the function and structure of the bottom of the granulated tower; Low investment cost, low operating costs, good economy.

It can achieve the best whitening effect of the granulated tower basically without white smoke, and realize the comprehensive economic and social benefits of waste heat utilization, environmental quality, energy saving and consumption reduction, acid-base neutralization, corrosion delay, desulfurization and environmental protection, and cost reduction.

Technical characteristics of desulphurization and whitening of blast furnace granulated steam waste heat recovery

1, WHBJ low resistance cloud dynamic swirl atomization technology;

2, fog and slag removal two-in-one technology;

3, multi-effect supercharger induced wind technology;

4, anti-explosion and mixed wind technology of whitening granulation tower;

5, wear-resistant longevity to strengthen anti-corrosion technology;

6, water fog recovery technology

WHBJ method of blast furnace slag water waste heat utilization dehumidification blast technology

1. Feasibility of the project

After the blast furnace ironmaking slag is quenched by water, a large amount of 60 ~ 95℃ slag water is produced, which contains huge heat, but it contains a large number of solid particles and mineral fibers, and is corrosive, and it is difficult to use its heat. In the past 30 years, many iron and steel enterprises at home and abroad have tried to use the waste heat of flushing slag water, but today, in addition to the application of heat exchange heating in northern winter, it has not been fully and effectively used, especially the large blast furnace has not been applied.

2. Process technology scheme

This case intends to adopt the "blast furnace slag water direct heat exchange waste heat recovery technology" and the special "slag water heat exchanger" as the technical scheme of the heat extraction system, which has the characteristics of no filtration, full water heat extraction, simple operation, small maintenance and high reliability.

According to the situation that the two sets of slag discharge periodically alternate in the operation of the blast furnace, the hot medium water return water is switched into the slag water waste heat recovery system. Each set of slag flushing system: After the blast furnace slag flushing water through the lifting pump, through the switching valve group into the heating station slag flushing water heat exchanger, after heating into the cool water tower, and then through the slag flushing pump to wash the slag; You can also take the heat directly to the slag. Two blast furnaces take heat at the same time through the hot medium water valve scheduling into each slag water waste heat system, the maximum recovery of slag water waste heat water supply quality.

3. Process flow chart

 

 

　　Characteristics of waste heat utilization technology

1, large recovery heat, high heating quality: the system directly extracts the original slag water system of the slag hot water, without adding a filter system directly into the slag water heat exchanger to take heat, after the heat is taken and cooled back to the original system slag recycling, and can be easily switched online with the original system, the original production system does not have any adverse impact. The technical solution avoids a large amount of cleaning, transportation work and heat loss due to filtration, and maximizes heat recovery.

2, anti sedimentation blockage, simple operation, reliable operation: slag water heat exchanger with anti sedimentation blockage of the special slag water plate heat exchanger, the system does not have a filter, the overall system process is short, high reliability. The heat exchange plate is arranged vertically, the bottom is provided with multiple backwashing cones, and the hydraulic valve is configured to realize automatic cleaning and slag removal.

3, the operation room is set up remote control system, the whole system adopts PLC remote control automatic operation, do not need to add special operators, only need regular inspection.

4, low operation consumption: the system can directly use (appropriate transformation) the original slag pump, directly extract the slag water on the outlet pipe into the heat collection system, and then return to the original system after cooling the slag water for recycling. The operation interference and power consumption caused by the water imbalance brought by the new slag water extraction pump to the system are avoided.

5, simple layout, small footprint: In addition to the control system needs to be arranged indoors, other facilities can be arranged outdoors, occupying less area. The control system cabinet and operation can be co-located with the existing control cabinet and operation of the slugging water system, or a small distribution control operation room can be built.

6. Low maintenance and easy washing: the heating system of this technical solution does not need maintenance in normal operation, only after the end of the heating season, open the flat cover of the slag water heat exchanger for simple cleaning and washing and then seal the water injection protection.

7, no secondary pollution: the technical solution system is basically closed operation, in the process of operation, in addition to the heat is taken out of the slag water, the rest follow the principle of where to go, neither change the balance of the original system, but will not produce secondary emission pollution.

8, stable heat, small fluctuations: slag pool, heat medium water tank and large heat exchange ratio of slag water heat exchanger can store heat, and keep the heat exchange as stable as possible. The steam reheater can be used as a means of emergency response and peak regulation for water heaters.

9, iron pre-cooling demand: spring, summer and autumn three seasons (early March to the end of October) blast furnace cold air dehumidification + winter (early November to the end of February) sintering and coking flue gas desulfurization dust removal white with cold demand, to achieve the integration of iron pre-waste heat utilization and flue gas white.

 

　　The characteristics and social significance of WHBJ self-cleaning super clean/waste heat recovery/desulfurization white elimination/waste heat utilization integrated blast-furnace slag treatment technology

　WHBJ method self-cleaning super clean/waste heat recovery/desulfurization white elimination/waste heat utilization integration technology, while solving many problems such as slag water self-cleaning super clean, slag water separation, steam white elimination and heat recovery, desulfurization and acid rain corrosion, slag water acid and alkali and corrosion inhibition, environmental protection discharge, etc. Only the hidden annual income of steel structure parts and slag water equipment in blast furnace area corrosion mitigation and life extension plus the annual water saving cost of white elimination. The annual comprehensive economic benefit will reach 14.1068 million yuan, and the investment cost can be recovered in less than two years. If coupled with the investment of the second-phase slag water waste heat lithium bromide dehumidification blast energy saving technology, the annual comprehensive economic benefits can be increased by 34 million yuan, and save the second-phase refrigeration power consumption of 5242kW frequency conversion power supply and distribution facilities initial investment of 5 million yuan.

WHBJ self-cleaning ultra-clean/waste heat recovery/desulphurization/waste heat utilization integration technology has the following advantages: low operating cost, using the existing blast-furnace slag water system for waste heat utilization desulphurization and waste heat elimination, without adding additional water treatment and cooling operating costs; The function and structure of the bottom of the granulating tower are preserved, and the function of desulfurizing and eliminating white is completed by using the upper space of the granulating tower. It has the advantages of low investment cost, low operating cost, good economy and outstanding environmental protection significance. Now after the national unified requirements to carry out the transformation, at least need to increase the investment of more than 50 million; If we consider the suspension of blast furnace due to renovation, the loss will be even greater. At present, one step in place, cost-effective and social benefits are the most significant.

The whitening solution can achieve the best whitening effect of the granulation tower basically without white smoke, which is a major breakthrough in the treatment process of iron smelting slag, solves the last and only unresolved plume emission in the metallurgical industry, and realizes the comprehensive economic and social benefits of waste heat utilization, environmental quality, energy saving and consumption reduction, corrosion retarding, desulfurization and environmental protection, and cost reduction. It has important political significance to publicize Liugang Group's emphasis on environmental protection, and has become a highlight of the construction of steel base, and will certainly become a successful example of Liugang Group leading the industry's technological progress.