The invention provides a negative pressure
optimal control method of a BFG boiler. The negative pressure
optimal control method comprises the following steps that a
hearth negative pressure setting value is subtracted from a
hearth negative pressure measuring value to obtain a
hearth negative pressure deviation
signal; the hearth negative pressure deviation
signal is inputted into a PI controller,the PI controller calculates a PI operation output quantity; an air supply quantity corrected by
oxygen amount is multiplied by feedforward
gain to obtain an air supply quantity feedforward calculation output quantity; pressure of the
blast furnace gas main
pipe is multiplied by the feedforward
gain to obtain a
coal gas quantity feed-forward operation output quantity; the PI operation output quantity is added with the air supply quantity feedforward calculation output quantity and the
coal gas quantity feed-forward operation output quantity, and a variable-frequency input quantity of an induced draft fan is obtained; and the output of the induced draft fan is adjusted through the variable-frequency input quantity of the induced draft fan, and then the negative pressure of the hearth is adjusted. According to the negative pressure
optimal control method of the BFG boiler, not only can induced wind
frequency conversion control be used for carrying out continuous deviation adjustment onthe negative pressure of the hearth in response to an
air volume change, also the change of the
blast furnace gas quantity can be quickly responded, so that the pressure of the hearth is guaranteed tobe micro-negative pressure, the
combustion of the boiler is stabilized, the internal disturbance of the
system is inhibited, and the running stability of a generator set is improved.