AUTOMATIC CONTROL METHOD OF BOILER LOAD WITH DIRECT-FIRING PULVERISED FUEL SYSTEMS AND SYSTEM FOR ITS IMPLEMENTATION Russian patent published in 2011 - IPC F23N1/02 

FIELD: power industry.

SUBSTANCE: when boiler heat load (BHL) control receives the signal from system of higher level (for example from unit power control), it acts on primary air flow rate controls, thus providing proportional change of primary air flow rate to mills. As per the change of primary air flow to each pulverised fuel system the signal dynamically converted in series connected differentiator and integral-differentiating link is supplied to input of load control of the appropriate mill, which when influencing the change of fuel flow rate provides inertia-free dust discharge from mill together with change of primary air flow. As per deviation of mill feed from the specified value the signal dynamically converted in inertial link with characteristic of "mill fuel flow - boiler load" control channel is supplied to inlet of BHL control. As a result, invariance of BHL control to internal disturbances in fuel supplied to mills is provided. When primary air flow is restricted, error signal between the specified and actual primary air flow is supplied to inlet of mill feed control, thus increasing the fuel flow and enlarging BHL control range. In order to prevent mill overload, error signal supplied to mill feed control inlet is restricted to the value of maximum allowable load (power) as per mill mass tumble conditions.

EFFECT: complete invariance of control system to internal and external disturbances and improving boiler load control quality, enlarging the control range of efficiency of pulverised-fuel systems in case of restricted primary air flow, preventing mill overload and improving operating reliability of pulverised-fuel systems and boiler as a whole.

8 cl, 2 dwg