Дослідження динамічних властивостей непрямого нагрівника нафти як об’єкта автоматичного керування

Intermediate heat transfer heaters are widely used for the preheating of oil and gas to reduce the viscosity of oil during its transportation through main pipelines or for heating gas before pressure reduction to prevent the formation of hydrates, which occur because of the Joule-Thomson effect. One of the main components of a heat transfer heater is a cylindrical or rectangular bath filled with plain water or water with additives, inside which a coil is placed, through which the working fluid (oil) flows. Typically, indirect heaters use plain water. The water bath is heated by flue gases passing through fire tubes. The flue gases may originate from various sources, such as the combustion of oil refining by-products, specifically gases after oil distillation. The fire tubes are structurally connected to the combustion chamber, where natural gas is burned. Thus, an intermediate heat transfer heater is a complex dynamic system in which heat is transferred to the working fluid (oil) through several intermediate stages. The created mathematical model of the dynamics of the heat transfer heater considers the sequential heat transfer processes from one element to another. Each element in the heat transfer chain is described by a nonlinear differential equation derived based on the law of energy (heat) conservation. This approach to describing the dynamics of the heat transfer heater generates a system of differential equations, which, in addition to input and output variables, also includes intermediate variables such as the temperature of the intermediate medium (water), the temperature of the coil walls, and so on. After linearizing the system of differential equations, the intermediate variables were eliminated, which made it possible to obtain a linearized mathematical model of the heater suitable for the synthesis of a multi-loop automatic control system for the indirect heater