Tar cannot be separated from water

Reply to 1#: The past is like smoke when closed one’s eyes; it must be related to coal. The brightness of the oil surface is poor, and there are many particulate impurities felt upon touch. We’ve encountered this issue as well, but it improved after changing the coal mixture!

The density and viscosity of tar, as well as the toluene-insoluble and quinoline-insoluble substances, all increased significantly. We have encountered such phenomena before, and we initially suspect that it is mainly related to changes in the type of coal used in the coke oven, with temperature control at the oven top also playing a certain role. At the same time, here we also have the conversion of top-mounted coke ovens to tamped coke ovens, which also has a significant impact on tar.

It’s probably due to an excessive amount of coal powder in the raw gas coming from the coke oven; only tar containing such coal powder would behave in that way – it’s a process-related issue

It’s probably due to an excessive amount of coal powder in the raw gas coming from the coke oven; only tar containing such coal powder would behave in that way – it’s a process-related issue

It’s probably due to an excessive amount of coal powder in the raw gas coming from the coke oven; only tar containing such coal powder would behave in that way – it’s a process-related issue

1. Overview Apart from coke oven gas, ammonia and tar produced by the spray condensation of coke oven gas are the two main by-products in the coking process. The economic benefits generated by tar can help coking plants offset the cost pressures associated with gas washing. Although circulating ammonia water does not bring economic benefits like tar, if not properly managed, it will not only affect the production process but also pose challenges related to environmental emissions. In many ways, tar and oil are very similar; they are resources that are becoming increasingly scarce. The coking industry in modern Western countries is placing increasing emphasis on coking processes that do not involve recycling, and in the future, the tar market is bound to experience a situation of supply falling short of demand. Therefore, optimizing the recovery process to maximize the recovery of tar produced by the coking process will bring considerable economic benefits to coking plants, both now and in the future. Due to process issues and site constraints, improving the quality of tar ammonia solution by adding more equipment is limited. The approach adopted by foreign companies to address this problem is to add chemical agents during the production process in order to enhance the separation of tar from ammonia, thereby reducing the viscosity of the tar. This not only achieves dehydration but also prevents the tar contained in the recycled ammonia from depositing in the system’s equipment. Currently, there are several chemical methods available internationally to improve the quality of tar, mainly including the following two types: water-based solutions and oil-based solutions. This chemical approach, combined with improvements in the operation of on-site equipment, has yielded good results. · Water-based solutions (demulsifiers) typically involve adding chemical agents to the tar products, which then enter the storage tanks. After staying there for a certain period of time, these water-based agents break down the emulsions, allowing ammonia to be separated from them and to flow back into the system. This technology can effectively reduce the moisture content of tar, but it has little or no effect on the quality of recycled ammonia water. · The oil-based technical solution involves adding tar viscosity reducers and demulsifiers to the gas collection pipes and bridge pipe spray circuits. This approach not only improves the tar dehydration rate but also has a positive effect on the quality of the recycled ammonia water. Narco tar dehydrating agent is also an excellent anti-adhesion agent; it forms a film on the surface of the tar, thereby **reducing** its adhesiveness. Another factor affecting the tar dehydration rate and the quality of the recycled ammonia water is the content of quinoline-insoluble substances, as these substances form stable emulsions with the tar and ammonia water. Under normal conditions, quinoline insolubles have no significant impact on the separation of tar and ammonia water, but given the quality issues associated with tar and ammonia water, it is a factor that cannot be ignored. This chemical solution can reduce the problem of tar-ammonia separation caused by quinoline insolutes. Currently, the countries that use these chemical technologies to improve the tar-ammonia water separation process are **Canada, the United States, Japan, Brazil, Chile, and some members of the European Union**. Especially in Japan and South America, many large international steel companies’ coking plants have adopted these technologies over the past two years. 3. The importance of quality control for tar and ammonia water. Ammonia water and tar are produced simultaneously, and they are then treated together; however, after passing through a gas-liquid separator, they are processed separately. However, due to the design of the gas washing process, they are combined in many steps. This characteristic of sometimes separating and sometimes combining causes many problems throughout the entire production process. To meet both environmental emission requirements and the demands of the tar-ammonia separation process as well as the tar recovery process, coking plants must pay attention to the management of ammonia and tar quality. Strict and proper quality control of ammonia-tar can maximize economic benefits while reducing operating costs. 3.1 Ammonia: Even if all the tar present in ammonia is separated, the properties of ammonia itself still have a direct impact on the production process and operating costs. We believe that clean ammonia still causes corrosion and scaling in production systems. The main reason for corrosion caused by ammonia water is the presence of ammonia, cyanides, H2S, CO2, and other pollutants in it. There are very few measures that can essentially eliminate corrosion. Theoretically, there should be no calcium present in ammonia solution. However, in practice, small amounts of calcium are often detected in ammonia solutions (