Babcock-hitachi Kabushiki Kaisha

Yukio Fukayama

Shigeyoshi Kawano

Taku Oshima

Atsushi Kuramoto

A control system for a pulverized coal fired boiler provided with a pulverized coal producing equipment including a coal feeding section, a milling section and a classifying section and an adjuster for adjusting a coaling rate thereof, and a pulverized coal burning equipment for burning the pulverized coal supplied from the pulverized coal producing equipment includes an estimation apparatus for estimating a coaling rate of coal out form the pulverized coal producing equipment, and an apparatus for operating the adjuster to adjust a coaling rate of coal supplied from the pulverized coal producing equipment to the pulverized coal burning equipment on the basis of an estimation of the estimation apparatus. The estimation is conducted by calculation of mathematical models which are obtained with taking the physical mechanism in the pulverized coal producing equipment and simulate a heat input with higher accuracy.

Control system for pulverized coal fired boiler

A boiler/turbine plant controlling apparatus comprises a circuit for driving a turbine inlet steam flow regulator valve on the basis of a difference between a load command signal adjusted by a thermal stress value of a turbine and an actually measured output signal of a plant; a circuit for driving a boiler feed water flow regulator valve on the basis of a difference between a value which is obtained by adding a boiler feed water amount with a super heater feed water amount and a value represented by a boiler input command signal; a circuit for driving a fuel flow regulator valve in accordance with an actually measured fuel amount and a fuel command signal corrected by a difference signal between a primary steam temperature setting signal and a steam temperature signal representative of a primary steam temperature measured value; a circuit for driving a super heater water feed valve on the basis of a difference value between the primary steam temperature setting signal and the steam temperature signal; a circuit for calculating a steam temperature drop through the steam flow regulator valve on the basis of an opening degree of the steam flow regulator valve disposed at an inlet of the turbine and a temperature and pressure of steam at the inlet of said steam flow regulator valve; and a circuit for correcting the steam temperature setting signal on the basis of the calculated value of the calculating means.

Apparatus for controlling boiler/turbine plant

A boiler control system includes a first device for measuring or computing a rate of change in steam temperature and a generated thermal stress in a pressure part of a boiler, and a second device for controlling steam temperature or a rate of change in the steam temperature at the pressure part of the boiler in accordance with a desired value, and a third device which has functions for storing in a memory combinations of the steam temperature and the thermal stress at each moment as obtained by the first device. The third device determining, from the combinations stored in the memory, a relationship between a steam temperature changing rate and a maximum thermal stress caused by the steam temperature chaning rate, determines, in accordance with the relationship, a steam temperature changing rate limit value necessary for maintaining an actual thermal stress in the pressure part of the boiler below a maximum thermal stress limit value which is predetermined beforehand or which is given for each start-up of the boiler, and delivers the steam temperature changing rate limit value or desired steam temperature value obtained by integrating the steam temperature changing rate limit value to the second device as the desired value.

Boiler control system

Thermal stress of a metal portion of a pressure-tight tube is calculated on the basis of calculated values of a temperature distribution calculator for calculating the distribution of temperature at positions equidistantly arranged in a direction of the thickness of the aforesaid tube on the basis of measured values of metal portion of the aforesaid tube, whereby the thermal stress being changed momently is accurately measured and monitored. Further, there is provided a calculation cycle setter for presetting calculation cycles on the basis of measured values of the fluid temperature in the aforesaid tube. The calculation cycles are made short when fluctuations in the measured values of the fluid temperature are large, while, the calculation cycles are made long when fluctuations in the measured values of the fluid temperature are small.

System for estimating thermal stress of pressure parts

A boiler starting system for starting a boiler which has a superheater and at least two reheaters. The boiler starting system has a steam extracting line for extracting the steam from the steam inlet side or an intermediate portion of the superheater, and a steam supply valve by which the extracted steam is supplied to the reheaters. The flow rates of steam through the superheater and each reheater are controlled independently to realize optimum steam temperature rising characteristics, without requiring increase in the capacities of valves and other elements of the starting system.

Boiler starting system

An apparatus for controlling a starting operation of a boiler which comprises a super heater, a super heater bypass valve, a turbine bypass valve and a fuel flow rate regulating valve. A temperature detector detects a temperature of the steam at a predetermined portion of the boiler. A pressure detector detect a pressure of the steam at the predetermined portion of the boiler. A desired change rate arithmetic unit calculates a desired steam temperature change rate value and a desired steam pressure change rate value on the basis of the steam pressure, the steam temperature, a desired pressure increase value, a desired temperature increase value, a saturated temperature change rate limit and a temperature increase change rate limit. An optimum operation arithmetic unit calculates opening degrees of the super heater bypassing valve, turbine bypass bypass valve and the fuel flow rate regulating valve, respectively, on the basis of the steam temperature, the steam pressure, the desired steam pressure change rate value and the desired steam temperature change rate value obtained by the desired change rate arithmetic unit. A compensation arithmetic unit compensates for the respective opening degrees obtained by the optimum operation arithmetic unit, on the basis of the change rates of the steam temperature and pressure.

Growing community of inventors

Kure, Japan

Yukio Fukayama