Abstract: The convection section module of the heater is generally composed of non-welded joints including furnace wall, coil, intermediate tube plate, end tube plate and elbow box. The furnace walls with two-dimensional plane structure are easy to deform during transportation and hoisting process. Therefore, protection tie rods are generally added for reinforcement in engineering practice. Since there is no ready-made standard or calculation method for reference, the design and selection of the protection tie rods are usually based on experience and vary from person to person. Thus it is of greater randomness and has certain potential safety risks. This paper analyzes the impacts of various components of the module on the force of the tie rods briefly. It proposes a simplified calculation model of the tie rod force and deduces its calculation formula. Through comparing the data in the case with the simulation data, it is verified that the calculation model is of reference value in engineering application.

Key words: force analysis, strength checking, tie rods, convection section, heater