JGST Natural Gas Heating Oxidation Furnace

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Recently, the oxidation furnace, the core equipment of carbon fiber production line with independent intellectual property rights independently developed and manufactured by JGST, has been installed and commissioned in Hyosung (HYOSUNG ADVANCED MATERIALS) factory in Jeonju, South Korea. The acceptance was successfully completed, and the two key technical indicators of the oxidation furnace, the uniformity of wind speed and the uniformity of temperature, reached the international advanced level. This cross-border cooperation is the second cooperation between the two parties since the first oxidation furnace cooperation in 2019. It is another major milestone in the history of in the history of JGST equipment manufacturing, and the national brand in the field of carbon fiber equipment shines again on the international stage.

As one of the seven major corporations in South Korea, Hyosung Group started to independently develop carbon fibers in the early 2000s. In 2011, Hyosung cooperated with research institutes such as Korea Carbon Fusion Technology Institute in Jeonju, North Jeolla to develop TANSOME carbon fiber for the first time in Korea. So far, Hyosung has put into operation three high-performance carbon fiber production lines at its plant in Jeonju, North Jeolla Province. The products are mainly T700/T800 grade carbon fibers. As an oxidation furnace supplier, JGST is very honored to participate in the construction of the second and third carbon fiber production lines.

Based on the solid foundation laid by the previous cooperation and the stable and efficient operation of the oxidation furnace, Hyosung recently confirmed the order for the oxidation furnace required for the fourth production line to JGST. According to public reports, the new line will be put into operation in April 2023. The expansion is aimed at meeting the growing demand for storage of eco-friendly vehicle fuels such as hydrogen and natural gas, especially the revitalization of the hydrogen energy economy is expected to drive the demand for pressure vessels for storing gases, while the application of carbon fiber pressure vessels mainly for hydrogen fuel vehicles, hydrogen refueling stations and hydrogen transportation.

As the core equipment in the carbon fiber production line, the oxidation furnace plays a pivotal role in the entire production and product quality. The oxidation furnace delivered by Jinggong Technology this time and the oxidation furnace for the next 4th line are different from the current mainstream electric heating type oxidation furnace in China. For the first time, a natural gas heater is used as the heat source of the oxidation furnace. The RHT Indirect Air Heater features an industry leading burner, combustion chamber and exhaust duct into a self-contained unit for easy installation and optimum performance. At the same time, the RHT indirect air heater is also a fully integrated system, including: heat exchanger, combustion chamber, burner, combustion fan, gas valve group and combustion control system. The heater body is made of superalloy. Its basic working principle is: according to the set temperature of the oxidation furnace and the actual temperature of the furnace body, to adjust the opening of the natural gas inlet valve, so as to adjust the consumption of natural gas, and to adjust the heat output of the heater. After the natural gas is combusted in the combustion chamber, the high-temperature gas produced will exchange heat energy with the process air through the heat exchanger composed of tube bundles, and finally be discharged from the waste outlet. The combustion chamber and the heat exchanger are located in the circulating air duct of the oxidation furnace. The air in the furnace continuously flows through the surface of the combustion chamber and the heat exchanger to absorb the heat energy generated by the heater to heat the air in the furnace. The circulating air duct where the heater is located has undergone accurate calculation and professional CFD simulation to obtain the optimized air duct structure, which can make the circulating air evenly distributed on the surface of the combustion chamber and the heat exchanger, and ensure that the combustion chamber and the heat exchanger can be evenly distributed. It avoids local high temperature caused by unstable airflow, which leads to damage to the combustion chamber and heat exchanger. At the same time, it has the lowest process air pressure drop and reduces system losses.

RHT indirect air heaters also have the following features:
Isolation of combustion exhaust gas from process air
Furnace over temperature protection
Process air volume detection
Thermal expansion free floating design
Thermal efficiency 60-75%
Low process air pressure drop
Sturdy structure

In addition, the combustion system can have the following safety functions under the premise of satisfying the application:

Gas high pressure protection, gas low pressure protection, double-valve internal leakage detection, automatic purging, furnace over-temperature protection, combustion-supporting air detection, circulating air detection, self-checking UV flame detector, dual-fire detection automatic flame detection, etc.

At present, under the national general policy of energy conservation and emission reduction, it is imperative to reduce the energy consumption per unit of industrial added value. At this stage, the oxidation furnaces used in domestic industrialization are basically mainly electric heating. The installed power of the oxidation furnaces in most production lines has exceeded 50% of the total power of the entire line, which is a complete energy consumption. At the moment when the market is chasing high-efficiency and low-energy-consumption equipment, JGST started from the oxidation furnace. After nearly 2 years of continuous testing and optimization, it has successfully developed a natural gas-heated oxidation furnace and completed its industrial application.

Compared with the electric heating type oxidation furnace, the natural gas heating type oxidation furnace has the following advantages:
1) Project investment
Substantially reduce the input of high and low allocation of public works of the project
Reduce equipment electrical control and cable investment
2) In terms of operating energy consumption
Taking a conventional 3-meter oxidation furnace as an example, under no-load 250°C, the temperature of a single temperature zone is controlled for one hour. 19.6 cubic meters. A single carbon fiber production line is generally configured with 8-12 temperature zones, and the production line runs for more than 7,200 hours per year, and the reduction in operating costs within a year will be considerable.

Apparently, under the actual full load condition, the operating costs of electric heating and natural gas heating will be adjusted accordingly according to different raw wires, process temperatures, electricity prices and natural gas prices in different regions, and the cost reduction advantage of natural gas will also be reduced or enlarged accordingly. But the advantages are always there, especially in areas where industrial electricity is expensive.

In recent years, carbon fiber, as an indispensable strategic new material for our country's economic development and national defense construction, is in strong demand in the fields of wind power generation, pressure vessels, aerospace, sports and leisure, photovoltaic carbon and carbon products, as well as ever increasing demand for projects under construction and announced to be built in China. Most industries, from the large expansion of production capacity to the balance of supply and demand, have experienced the baptism of product quality and cost. In the future, among hundreds of companies, the main competition of carbon fiber will also be product quality and cost. We have reason to believe that the application of natural gas heating type oxidation furnace will become more and more popular.