In this paper,the atmospheric problems posing to coking industry are summarized from two aspects,i.e.state and local industrial policies and the status quo of air pollution in coking industry.The technical solution to ultra-low emission for coking industry is put forward,and the way of reducing air pollution emission is analyzed,which provides technical support for the authority of ecology and environment as well as coking enterprises.

In this paper,the relationship between the microstructure and thermal properties of coke was studied,and the characteristics of stomatal structure and optical structure of industrial coke with different CRI and CSR indexes were analyzed.The fixed solution loss test at 1，100 °C was carried out by continuous thermal weight loss method,and the strength index CSR25% after the coke solution loss at 25%.The relationship between coke thermal properties and microstructural parameters was established by multiple linear regression.It was found that the average thickness of the pore walls was most closely related to the CSR25%.The conclusion provides important support for refined coal blending,optimizing coke structure and performance.

A pair of vertical flues of JN60 coke oven combustion chamber are selected.The CFD numerical simulation is used to establish a coupled model of air depleted combustion intensity and combustion fluid multi-concentration field.The heat mass transfer process was simulated,and the calculation results are basically consistent with the design values.On this basis,heat flux density of the coke oven and turn point size were changed to minimize the NOx emission fundamentally.The simulation result shows that the heat flux density has much influence on the NOx,i.e.when the heat flux density is 4,800 W/m2,the NOx concentration is 742 mg/m3,when the heat flux density reaches 7,600 W/m2,the NOx concentration drops down to 135.1 mg/m3，reduced by about 600 mg/m3；similarly,the more opening of the turn point,the higher inner circulation rate,the wider reaction zone,the lower consumption rate of the reactant and the lower NOx formation as a result.

An integrated process and device for CDQ coke moistening,dust suppression and water recycling are introduced in the paper.In this process,not only the coke inside bucket is sprinkled with water for humidification,but also the steam and coke dust generated can be precipitated as well as the waste water can be recycled,which will be beneficial to energy saving,emission reduction and lowering operating cost as well.

This paper introduces technical standards of pilot oven，and principles and procedures of cokemaking tests;and expounds on the role of cokemaking tests in pilot oven and their guidance and application to real production.Cokemaking test in pilot oven plays a significant role in simulating production of industrial coke oven.It is used to scientifically evaluate coking coal，optimize coal blending and cokemaking process，reduce coal blending costs，predict coke performance as well as test technical feasibility.Cokemaking test in pilot oven provides technical support for industrial coke oven.

This paper analyzes changes of coke properties and grain size composition in the 6 m coke oven when heated by different gases.It is found that BFG-fired coke oven will have much easier coking process control，higher coke quality and better heating distribution in vertical flue.

The application of heat pump technology in 200 t/h CDQ project is introduced.A comparison is made for several options in terms of power output,energy consumption and energy to be supplied,etc..The result shows that the heat pump considered as a solution for power generation at engineering stage could increase total thermal efficiency,lower investment and land occupation for circulation system as well as improve comprehensive benefits for the CDQ project as a whole.

Emergency system for pusher machine was introduced,which can effectively protect the pusher machine for safety purpose and prevent the pusher ram,leveling bar and guide cage from being burnt in case of power failure.It also turned out to be reliable in performance and low in cost, which can be widely used in production.

This paper introduces an upgrading proposal of a 140 t/h CDQ system,and presents differences in production before and after the modification.After the upgrade,the CDQ system steadily operated.The problem of uneven drops in the cooling zone was resolved.The temperature of discharged coke was lowered by 15 ℃.The suction at inlet of the boiler and the resistance of the CDQ system were also reduced.These helped to lower the operating costs of the CDQ system.

This paper introduces the conditions of two blocks of 6 m coke ovens and analyzes the main causes of end flue damage as well as the advantages of re-bricklaying for oven end flues with low expansion rate silica bricks by uncovering from battery roof.Thus solutions can be given to the damage and deformation on heating wall at end flues and the oven end emission escaping and flaming as well.Compared with using ordinary silica bricks, the overall time schedule can be shortened by around 110 days, coke can be saved by 23 210 tons approximately and coke output can be increased by 50% plus.

A test is introduced for lowering the NOx in the emission of coke oven waste gas by controlling the pollution source. The test result shows that the NOx is reduced in the coke oven waste gas since the waste flue gas is recycled and blended with combustion air, which also remarkably improves coke oven heating in vertical direction.

The process of sulfuric acid making with fluid sulfur slurry as feedstock is characterized with safety,environment protection,stability and high automation.The key to control of diluted sulfuric acid formation amount is to strictly control the concentration of sulfur slurry into the incinerator.If ammonium sulfate process is adopted for ammonia removal,the diluted sulfuric acid,as by\|product,can be delivered to ammonia sulfate saturator and completely recovered.

Lean coal solvent hot extraction is studied with Lewis-acid metals as catalyst.The result shows that the catalysts help to improve hot extraction rate，in particular zinc sulfate has the best performance，with hot extraction rate of 46.1% and optimum dosage concentration of 5%.

Discussion is made in this paper in terms of process flow，technical features and purposes of coal tar distillation at present.The newly developed negative pressure distillation process of coal tar and its features are introduced in details.By comparison，the strong points and values of the new process is highlighted.It provides a better technology for new or retrofitted tar distillation units in China.

We obtained optimized operating parameters by analyzing the datum such as operating temperature,steam consumption,reflux ratio and products quality,etc.by numerical simulation.The fine tuning of the operating system can not only guarantee qualified crude benzol products,but also reduce naphthalene content in circulating wash oil so as to prevent the naphthalene from separating out inside benzol scrubber and decrease the naphthalene content in the purified gas,which will lay a solid foundation for further treatment of the coke oven gas.

Problems were found during maintenance such as uneven slagging in modified pitch reaction vessel,partial collapse of deflectors in heater as well as guard wall peel-off from the reaction vessel.By improving the deflectors and adding temperature measuring points for circular tail gas flue,satisfactory results can be achieved,such as the slagging can be minimized at the bottom of the vessel,deflectors inside the heating chamber can be effectively monitored and oil leakage from the reaction vessel can be avoided.

This paper introduced a process of feedstock tar dehydration by using waste heat from oil-vapor on top of pre-dehydration column and dehydration column recovered by heat pump.This process is a new and energy-saving technology,with low operating cost and easy operation,which can be widely used in this industry.

The gas purification plant is equipped with storage tanks of coal tar,crude benzol,and ammonia liquor,etc.,and NH3,CmHn and H2S could be released from those tanks.On account of medium characteristics of the tanks and composition of the volatile gases,improvement is done in aspects of tail gas collecting,safety measures and operating procedures.As a result,this attempt can not only meet environmental requirements,but also reduce annual costs about 600，000 yuan.

In coking project (Phase I) of Baosteel, the SDA deSOx process is used to remove SO2 in the emission.The deSOx system is composed of spray scrubber and bagfilters.After purification, the concentration of SO2 in the emission is not higher than 30 mg/m3.This paper summarizes the potential risks in case of off-specification emission from coke oven, and gives the solutions.

In general,the contents of sulfur dioxide and sulfuric acid mist in the tail gas of sulfuric acid plant are relatively high,which makes it difficult to conform to strict environmental criteria.To this end,the tail gas should be further treated.This paper mainly introduces the treatment technology of SO2 and acid mist in tail gas forced absorption with sodium hydroxide solution.After the further treatment,the emission can meet the relevant requirements.

Pitch fume treatment in coal tar refinery is introduced,i.e.the processes of absorbing,adsorption,electrostatic precipitation and incineration,in particular the combination of wash oil absorbing and incineration process,which can be promoted in production for its proved easy operation,low cost and good purification result.