3- Efficient gas-liquid-solid separation equipment for the technical upgrade of tar removal separators in coke oven gas dust collectors

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This post was last edited by luoli519 on 2022-11-30 21:35. Recently, many companies have encountered problems with inefficient operation and high operating and maintenance costs when it comes to removing dust from coke oven gas and recovering tar in environments characterized by high temperatures, high dust levels, and high tar content. Besides, the economy has been sluggish lately, creating a lot of pressure. A friend told me that the temperature of the coke oven gas is between 400 and 550 degrees, sometimes higher; it also has a high level of dust and tar. Are there better technical upgrades and equipment available to address the problems of poor performance and high operation and maintenance costs? Let’s take a look back together; the processes currently used in China can be roughly divided into: 1. Electrostatic dust collection. However, issues such as insulation in high-temperature environments, sealing, high-temperature corona, and electrode coking and coating have long plagued businesses. Some companies have added several backup units and even installed infrared heating on the electrodes, investing a lot of money; yet the problems persist, with the equipment having to be turned on and off frequently, resulting in high costs. II. Metal filter elements. Metal filters have no issues in terms of high-temperature resistance and filtration precision. The problem is that, for treating the coke oven gas generated in large-scale coal upgrading processes, which is characterized by high temperatures, high dust levels, and high tar content, a large number of filter elements are required, as well as several spare units ； What’s worse, the high dust content contains tar, which quickly clogs the surface of the filter elements; as a result, their lifespan is short, and their cost is not lower than that of electrostatic precipitators. Frequently replacing filter elements covered in tar and dust, as well as maintaining filter equipment, is an even more arduous task. III. Washing. Washing high-temperature coke oven gas with a large amount of water can, to a certain extent, remove dust and tar. The problem is that this method consumes a large amount of water; the washing water, which contains organic substances, inorganic salts, dust, and other complex components, requires lengthy and difficult processes for heat exchange, separation, and other forms of post-treatment ； After the washing water vaporizes, during the subsequent condensation process to remove residual tar and water droplets from the gas phase, the liquid that is separated still contains complex components such as organic substances, inorganic salts, and dust, making further treatment difficult. With increasingly stringent environmental regulations, this method can still be used to some extent in cases where water-coal slurry and pulverized coal gasifiers operate at temperatures above 1000°C to convert all tar into carbon compounds; however, water consumption and subsequent treatment remain major challenges. So, are there any options within the country? Let’s shift our focus to similar process packages abroad; as we all know, Wood and Bowers are leading international EPC firms for coke oven and blast furnace gas projects. For coke oven gas with high temperature, high dust content, and high tar content, a G54 multi-factor cyclone separator is first used to capture the majority of the dust. After the tar condenses through indirect cooling (air cooling or water cooling), it is recovered using a G50 vane separator. Both types of separators belong to the category of dynamic separation; they do not rely on the blocking effect of tiny pores on the surface of the filtering medium to achieve separation. As a result, they have excellent resistance to clogging, high precision in separation and high efficiency. No backup units are required, and the separation elements can be easily maintained during overhauls without the need to replace them with new elements. The application of this equipment in large-scale projects in China has been highly successful, including the catalyst capture, recovery, and separation units for naphtha catalytic cracking gas in CNPC’s Qinzhou and Quanzhou projects, the gas-liquid separation unit in the benzene washing tower of the Handan Iron and Steel Plant built by GE, and the high-temperature gas dust removal and separation unit in the coal-to-gas conversion furnaces of Shenhua Ningxia Coal. It is recommended that you consult Engineer Huang from Shenhua Ningmei Olefins Company to obtain information and verify the relevant usage details. Shenhua Ningmei is the party that directly contacted our company to have the multi-factor cyclone mother-son separator components designed and manufactured; the rest were supplied by intermediaries. The scale of domestic lignite upgrading projects is large, and their number is increasing continuously; currently, their economic benefits are relatively good compared to other coal chemical projects. It is recommended that owners of similar projects in China and design institutes carry out technical upgrades and renovations of the process equipment in such projects, thereby creating new technical upgrade packages for similar projects in the country. This will help improve the level of domestic technical equipment, enable smoother project operation, reduce operating costs, and increase the profitability of these projects. We welcome colleagues to join in the discussions, offer more ideas, and work together to develop better technical solutions and intellectual property rights specific to China. Everyone is welcome to share their ideas!