Qilu styrene plant recycles 3,000 tons of exhaust gas every year

In recent years, the Qilu styrene plant has attached great importance to the transformation and management of environmental protection facilities. Based on the total recycling of liquid waste, the utilization of by-product gases has been increased. From January to October this year, 2,500 tons of exhaust gas are expected to be recovered. It is expected to exceed 3,000 tons and its recovery rate will reach 100%, which is rare in the past years and has played a good role in protecting the surrounding environment.

In the process of producing styrene by ethylbenzene dehydrogenation process, the plant produces a large amount of waste gas as a by-product. The waste hydrogen produced alone has more than 300 kilograms per hour (including 180 kilograms of hydrogen and a small amount of organic matter such as benzene). There are also other sealed exhaust gas 30 kg / hour. These exhaust gases can be burned. Their calorific value is as high as 15,000 Kcal/Kg, which is 1.5 times the calorific value of methane. It is very suitable for fuel use, but the control is difficult and dangerous.

Exhaust emissions into the surrounding environment not only cause environmental pollution, but also a huge energy waste, so every styrene production unit treats the comprehensive utilization of dehydrogenation waste gas as a key work. As the Qilu styrene plant has continuously increased the comprehensive management of wastes in the production management in recent years, the exhaust gas recycling rate has increased year by year. Through the modification of the exhaust gas recovery system, the phenomenon of entraining organic matter (mainly benzene, ethylbenzene, styrene, etc.) into the exhaust gas is thoroughly solved; through the optimization of the steam superheater fuel control system, the exhaust gas produced is used for fuel; The reform of the sealed gas system solved the difficulties that were previously impossible to combine with the furnace. According to incomplete statistics this year, this year, in addition to the one hundred kilograms of organic matter that can be recovered per hour, the heat load provided by the waste hydrogen gas and the sealed gas as the steam superheating furnace reaches more than 80% of the total furnace heat load, according to the calorific value. The conversion is equivalent to saving more than 400 kg/hour of fuel gas.

In addition, as the fuel produced in the production process as fuel has the following advantages: 1. Complete combustion, no secondary pollution; 2. The burner is not easy to coke, help stabilize the furnace operation; 3. The control system after the reform is more reasonable The heating efficiency of the furnace has been significantly improved. The recent evaluation of the overall performance of the styrene unit superheater shows that its thermal efficiency is above 90%, which is much higher than that of other fuel types.

In recent years, the production cost of this device has dropped drastically, and it is closely related to the reasonable recovery of exhaust gas. This year, except for the period of equipment maintenance, the exhaust gas will be fully recycled. With the cumulative recovery of more than 3,000 tons in the whole year, huge economic and social benefits will be generated for the device.