The Study Of Numerical Simulation And Control Strategy On Fired Heater

As large-scale of oil refining and rising requirement to the environmental protection, diesel hydrogenation is attached more importance to as a mean to improve diesel quality; As important thermal technology equipment in diesel hydrogenation technology, the design and control of fire heater for diesel hydrogenation have a direct influence on the subsequent hydrogenation reaction; At the same time, the mandatory requirements of "energy conservation and emissions reduction" are proposed to enterprise in our country, higher requirements are put forward for the design simulation and control of fire heater for diesel hydrogenation.Based on the background of diesel hydrogenation units, whose annual output is 2 million tons, the author established a heat transfer model for radiation in fire box, check the heat transfer in furnace with Lobo- Evans method on the basis of the preliminary design of the existing furnace, according to the technological characteristics. Select true component method to cut diesel fractions, and 14 kinds of normal alkanes to describe the components of diesel, mixture of diesel and hydrogen flow into the fire heater in two phases. On this basis, use XFH module in HTRT software to simulate the fire heater, and compare the main parameters with design values. Results show that the key parameters of the heating furnace conform to design value well, can provide the basis for further improving the performance of heating furnace.The fire heater is a system with multi-variable, large delay, strong disturbance. The author advanced different control strategies on different controlled variable:, Put forward the exit temperature and furnace temperature cascade control scheme, in view of the furnace temperature response rapidly to the disturb of fuel gas pressure; According to the fluctuant and measurable characteristics of blast volume, propose the control scheme of feedforward-feedback on stove pressure; Two branch temperature balance control scheme is presented considering that the structure of equiflux heater with single lied tubes has double room. On the basis of the dynamic model of heating furnace, simulink simulation analysis was carried out on the heating furnace control system, and the controller parameters are set. Results show that the proposed control strategy is effective and superior to conventional control strategy.