Based on the two newly commissioned toluene hydrogenation dealkylation benzene production units using THDA technology in China in recent years, this paper provides a comprehensive introduction to the technology from the aspects of reaction principle, process technology, key equipment, and energy consumption. Toluene undergoes direct thermal cracking to produce benzene under hydrogenation, high-temperature, and high-pressure conditions, with a single-pass conversion rate of around 83%. The unreacted toluene is recycled to the feed buffer tank, achieving a total product yield of approximately 98%. The reaction is exothermic, with an inlet temperature of 665°C, an outlet temperature of 720°C, a reaction pressure of 3.2 MPa, and a hydrogen-to-oil molar ratio of 6 at the outlet. The unit's energy consumption is 48.29 kgoe/t. Key equipment for this technology includes the toluene benzene reactor, heat-integrated feed exchanger, and reaction feed heater. To reduce investment, the reactor typically uses a cold-wall reactor with lining, where the lining material and thickness are critical design considerations. The heat-integrated feed exchanger must fully consider the tube sheet stress, as well as the expansion of the exchanger itself and the changes in operating conditions of the connected reactor that may cause expansion. The design load of the feed heater is primarily determined by the start-up conditions, but it also needs to consider the characteristics of the cold-wall reactor.

基于近两年国内新上的两套采用THDA技术的甲苯加氢脱烷基制苯装置，从反应原理、工艺技术、关键设备、能耗等方面对该技术进行了综合介绍。甲苯在临氢、高温高压条件下，直接热裂解制苯的单程转化率在83%左右，未反应的甲苯循环至进料缓冲罐，总产品收率可达98%左右。反应过程放热，入口温度为665℃，出口温度为720℃，反应压力为3.2 MPa，出口氢油摩尔比为6，装置能耗在48.29 kgoe/t。该技术的关键设备为甲苯制苯反应器、热联合进料换热器和反应进料加热炉。为减少投资，反应器一般采用带衬里的冷壁反应器，衬里的材料以及厚度是反应器的设计重点。热联合进料换热器需要充分考虑管板应力问题，同时考虑换热器本身的膨胀，以及直连反应器实际运行状况的变化而导致换热器产生的膨胀。进料加热炉的设计负荷主要由开工工况决定，但同时要综合考虑冷壁反应器的特点。