## 1 Introduction  
Exothermic catalytic reactions, such as Fischer-Tropsch synthesis (FTS) [1; 2; 3; 4] and diethyl oxalate hydrogenation [5; 6; 7; 8], have an important position in syngas conversion, which is primary to the utilization of biomass or coal resources. Diethyl oxalate hydrogenation and FTS are both strong exothermic reactions and the addition of hydrogen atoms to the molecule usually leads to the release of heat during the process. According to the previous study, the thermodynamic view reveals that FTS product deviation from ASF distribution occurs because the industrial FTS process is not generally in equilibrium except for only a few reactions, for example, the water-gas shift. However, according to thermodynamic analysis, the increase in temperature favors the hydrocarbon formation of short-chain, lower degree of unsaturation, or containing fewer oxygen atoms products, since the negative enthalpy change and Gibbs energy of all the FTS exothermic reactions in industrial conditions has a linear relationship with temperature [9]. Hence, the reaction temperature of FTS has a huge impact on the thermodynamically allowed products [10; 11], which makes temperature control so crucial in this kind of chemical process. From a kinetic point of view, exothermic reaction heat is beneficial to accelerate the reaction rate, though over-increasing the temperature may be detrimental to the exothermic reaction, namely the poor control of autogenous heat will lead to \"T runaway\" and make a mess of the process. Given the complex reaction characteristics of diethyl oxalate hydrogenation and FTS, the produced heats need to be removed promptly to avoid the buildup of heat and runaway of temperature in reactors. Therefore, the optimization of the process and improvement in operating conditions in the technical route of diethyl oxalate hydrogenation or FTS have been the focus of many researchers [5; 7]. Moreover, their product contribution is sensitive to reaction temperature [3; 12], which means large temperature fluctuations can negatively affect the yields of target products. To ensure the catalyst durability, guarantee thermo-mechanical reliability of the entire process, and dominate the product distribution, temperature fine control is particularly significant. Notably, some new materials have been tried to address the temperature control problem. For example, [PERSON] and [PERSON] et al. used encapsulated phase change material (PCM) to optimize the thermal transmission of FTS reactors, possessing a shift in the C5+ selectivity [13]. However, these new materials cannot be economically utilized in industrial devices due to the difficulty of universal adaptation and the high cost. The intelligent control of coal-based exothermic reactions, especially the artificial intelligent control of temperature, is of great significance in scientific research and practical application. Nevertheless, the heat generation rule is rather different and the enthalpy released from the exothermic reaction is an exponential function of temperature (Arrhenius principle), causing the temperature fluctuation in the reaction zone. It is urgent to improve temperature control accuracy. Fixed beds and slurry beds are common reactors used in the current industrial diethyl oxalate hydrogenation and FTS process; the temperature of fixed-bed reactors is generally controlled in the pressurized circulating boiling water system by adjusting the pressure of the steam drum. In essence, the steam generation of a reactor is like a steam boiler in a power plant. In the current production and simulation system, compared with the cooling method of cooling water heat transfer, the use of pressurized water for heat transfer is more conducive to the temperature of the reactor reaching a stable value and is conducive to improving the grade of energy utilization. Conventional steam drum control is a three-element controller generally deployed with PID controllers: feed-water flow, process level, and vapor flow [14].