The Babcock & Wilcox Company

Elsag International B.v.

Other

Azmi Kaya

Marion A Keyes, Iv

Ralph K Johnson

Roger Kammerer

Jeffrey A Beller

William H Moss

Thomas J Scheib

Michael P Lukas

Donald J Dziubakowski

Donald K Frerichs

Theodore N Matsko

Michael S Willey

Larry L Enterline

Alan C Sommer

Larry Rice

A neural network control based on a general multi-variable nonlinear dynamic model incorporating time delays is disclosed. The inverse dynamics of the process being controlled is learned represented by a multi-layer neural network which is used as a feedforward control to achieve a specified closed loop response under varying conditions. The weights between the layers in the neural network are adjusted during the learning process. The learning process is based on minimizing the combined error between the desired process value and the actual process output and the error between the desired process value and the inverse process neural network output.

Method and procedure for neural control of dynamic processes

A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same. The compensated control errors are utilized to modify the target values for the H factor and the initial chemical concentration by modifying the chemical charge and the time versus temperature operating parameters of the digestings to regulate pulp Kappa number and spent cooking liquor residual chemical concentrations of the process.

Method of modeling and control for delignification of pulping

System for modeling and control for delignification of pulping

A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized ot produce signals representative of the actual Kappa Number and the residual acid concentration in the digerter. The expected perturbations in Kappa Number and the residual chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same. The compensated control errors are utilized to modify the target values for the H factor and the initial chemical concentation by modifiying the chemical charge and the time versus temperature operating parameters of the digestings to regulate pulp Kappa number and spent cooking liquor residual chemical concentrations of the process.

A method and apparatus for controlling the delignification process by monitoring and minimizing variations in the Kappa Number and the digester residual chemical concentration. A parameter representative of the H factor for the delignification process and a measurement of the initial chemical concentration are utilized to produce signals representative of the actual Kappa Number and the residual acid concentration in the digester. The expected perturbations in Kappa Number and the residue chemical concentration are compared with target values for same to produce estimated errors due to mismatch which are compared with actual measured errors for these parameters to produce compensated control errors for same. The compensated control errors are utilized to modify the target values for the H factor and the initial chemical concentration by modifying the chemical charge and the time versus temperature operating parameters of the digestings to regulate pulp Kappa number and spent cooking liquor residual chemical concentrations of the process.

Apparatus for controlling the degree of cooking in a digester

Method for controlling the degree of cooking in a digester

A performance monitor generates a fouling factor which indicates the level of fouling of a heat exchanger having a heat exchange surface area and through which a heat exchange medium passes having a known specific heat. Temperature transmitters are utilized to obtain values for the input and output temperatures of the heat exchange medium as well as the temperature in the heat exchanger of a heat exchange fluid used to transfer heat to or from the heat exchange medium. Modules are used to generate a value for an actual heat transfer coefficient in the heat exchanger as a function of the temperatures, flow rate and constant parameters such as area and specific heat, for the heat exchanger. The actual heat transfer coefficient is compared with a nominal or original heat transfer coefficient to determine if any deterioration in the coefficients has occurred which reflects the fouling of the heat exchanger. A simple ratio of the nominal to actual heat transfer coefficient is taken as a measure of this fouling factor.

Heat exchanger performance monitor

Supervisory control system including an arrangement and process for controlling the operation of a dryer for the continuous adiabatic drying of a moist solid product with heated air for achieving the desired final product moisture content which would not exceed scorch level.

Supervisory control system for continuous drying

A system for the automatic and continuous determination of the efficiency of a fossil fuel-fired vapor generator for utilization by an automatic load control (88) to control the distribution of the system load among a plurality of generators, wherein various heat losses from various combustion sources are separately determined, the individual losses summed (80) and subtracted (86) from 100 percent to obtain a measure of the vapor generator efficiency.

Steam generator on-line efficiency monitor

A system for optimizing the performance of a plurality of energy conversion devices is disclosed. Measurements of fluid flow into and out of the energy conversion devices, the efficiencies of the conversion devices and the power produced by the conversion devices are used as inputs to function blocks in a logic arrangements. The function blocks cause a decrease in load demand to be applied to the energy conversion device having the lowest efficiency and an increase in load demand to be applied to the energy conversion device having the highest efficiency.

Distributed system for optimizing the performance of a plurality of

An enthalpy measuring arrangement for measuring the heat content of a substance which may in the liquid phase, vapor phase or a mixed phase of liquid and vapor, comprises a first enthalpy calculating module for calculating the enthalpy of the substance when in a two-phase condition utilizing a plurality of discrete function blocks. The specific volumes of the overall mixture is calculated using a density transmitter which measures the density of the substance. Tables are utilized to obtain the specific volumes of the gas and vapor part of the substance on the basis of a measured temperature for the substance. These values are in turn used to obtain a quality value which is multiplied by a value representing the difference between the enthalpys of the vapor and liquid components of the substance to obtain the overall enthalpy of the mixture. Another module with a plurality of function blocks generates the enthalpy of the substance when it is superheated or entirely in the vapor phase. A selector module is connected to the mixed and vapor phase calculating modules to determine which of the modules should be utilized and to calculate the overall enthalpy of the substance regardless of its phase.

Enthalpy measurement for two phase substance

An integrated control system for both the output and surge protection of a centrifugal compressor in a chilled, water system is provided by biasing the output of a feed forward and cascade centrifugal compressor output control logic module with the output of a coordinating control logic module, which utilized a surge control logic module output to establish the biasing signal.

Integrated control of output and surge for a dynamic compressor control

A cooling tower monitor for determining the performance of a cooling tower includes temperature transmitters for determining the input water temperature, the output water temperature and the surrounding temperature of the tower. A flow transmitter measures the output flow of water and a speed transmitter determines the flow of air through the tower. A relative humidity transmitter is also utilized to measure the surrounding relative humidity. The transmitters are connected to function blocks to generate a value corresponding to the performance of the cooling tower as a function of the parameters measured. A first set of function blocks utilizes the surrounding temperature and relative humidity to calculate the wet bulb temperature of the air outside the tower. This measurement is utilized in conjunction with the input and output temperatures as well as the air flow value to calculate a nominal or available water flow rate for the tower. A standard condition tower unit and rating factor for the tower are utilized in this calculation. The available flow is then divided into the actual flow as determined by the water flow transmitter to obtain the performance value.

Cooling tower monitor

An adaptive control for a process is disclosed which utilizes a process parameter calculator made up of simple function blocks which generate a plurality of process parameters, and a tuning parameter calculator, also made up of simple function blocks, for calculating tuning parameters from the process parameters. The process parameter calculator is provided with values for various disturbances, a set point, a control output from a process controller and process structure data including process sensitivity and nominal operating data. From these values, the process parameters are determined. The tuning parameter calculator is provided in addition to the process parameters, with performance parameters and design function for generating tuning parameters that are applied to the controller for modifying the control output in response thereto.

Adaptive process control using function blocks

A system for optimizing the control of the water temperature within a cooling tower is disclosed. The temperature and the relative humidity of the air outside the cooling tower are measured and are selectively utilized as inputs to a plurality of modules containing function blocks in a logic arrangement. The function blocks produce an output signal indicative of the wet bulb temperature of the outside air which is compared to the cooling tower water temperature causing the speed of the cooling tower fans to be adjusted in response to the temperature difference therebetween.

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Akron, OH, United States of America

Azmi Kaya