JP2007519089A - Method and apparatus for predictive evaluation of heat load for solid waste incineration facilities - Google Patents

Abstract

  The present invention relates to a method for predictive evaluation of a heat load generated by solid waste when put into an incinerator, and a related apparatus. The present invention is based on the measurement of the air pressure under the first primary air inlet and the temperature of the gas generated by auto-ignition, said measurement being the first immediately following the feeder supplying waste to the furnace. Performed in the combustion section. The method of the present invention allows the establishment of a relationship between the aforementioned parameters and the measured steam flow rate, wherein the steam (or the temperature of the combustion gas) generated from the boiler is associated with the furnace and waste This occurs as a result of complete combustion at the center of the furnace a few minutes after the actual incineration of the furnace. In this way, the difficulty associated with the internal time between the input waste and the effect of the waste on the steam flow (or combustion gas temperature) rate is determined. As a result, automatic adjustment of the device can be performed to control the flow of waste to the incinerator for solid waste.

Description

  The present invention here also relates to the heat load generated by solid waste when introduced into an incinerator (vibrating push rod grid furnace with movable grate or roll etc.) devised for this purpose. The present invention relates to a method for predictive evaluation of and a device related to predictive evaluation.

  Due to the nature of solid waste itself, for which many physical and chemical characteristics are unknown, solid waste combustion represents a complex and costly task in real time during incineration in a waste incineration facility To do. In fact, chemical composition, moisture content, lower heating value, rating, specific gravity, even instantaneous waste treatment capacity, know when this waste is taken into the furnace. It is not done.

  Only knowledge based on sampling campaigns carried out over a period of weeks by specialized agencies that implement mean statistical methods of solid waste characteristics is available. In addition, for incineration processes, when the incineration process runs continuously during that time, the amount of steam in the boiler associated with the furnace, or the combustion modified by the overall air inlet for equipment not provided with the steam generator Through the gas temperature, heat load values are also available. Thus, the heat load value makes it possible to have knowledge of the calorific value average and the waste treatment capacity for several minutes before the waste to be treated is introduced.

  However, when the amount of solid waste that may be taken up by the feeder is limited, the product throughput characteristics differ greatly from the average values given by the previous two methods.

  In fact, the aforementioned characteristics of solid waste (instantaneous processing capacity, chemical composition, calorific value, rating, etc.) can be considered as random variables. The average value and standard deviation, which are the only statistical methods for the variables, have been undertaken so far. As a result, the waste treatment capacity incorporated at every moment is a random variable realization. And it is difficult to associate a given property with the variable.

  This is because all furnace control methods are associated with other combustion parameters (temperature, air duct pressure, percentage of oxygen in the combustion gas measured in the steam generator, percentage of other pollutant gases, etc.) This is why it is based on a very stable and smooth feed rate, which has a very low and slow change during that time, mainly to take into account the average value of the steam volume (or the temperature of the combustion gas). To this end, the furnace control method includes setting a set point that meets the furnace control optimal conditions based on the average incineration process characteristics known during control operation. The disadvantages of setting this set point are that it is difficult and long to establish, fragile and has a significantly reduced operating range.

  Therefore, continuous steam flow fluctuations (or combustion gas temperature fluctuations) are particularly small when the average waste treatment capacity and the generated average generated steam flow (or combustion gas temperature) are well controlled. Present in capacity facilities (waste tonnage less than 10 tons per hour).

  Incineration facilities (heating furnaces, boilers, gas purifiers, etc.) will be designed to be large in order to adapt to these fluctuations. Therefore, the investment cost is excessive, the facilities are burdensome, and there is a certain standard deviation. Maintenance costs increase due to the need to set up and operate. Similarly, the start-up time is shortened because the trial operation of the facility becomes difficult. In addition, steam is sold to third parties either directly in process steam or in the form of electricity generation, but the facility must make the best use of energy sales contracts when steam flow variability is strong. I can't.

  These fluctuations also make it difficult to incinerate waste that produces by-products that do not comply with environmental regulations, such as large amounts of incombustible residues, combustion gas temperatures lower than current regulatory standards, and variability that can cause undesirable contamination. Become.

  The present invention provides a unique solution to the unknown problem of the physical and chemical properties of waste that is constantly charged in an incinerator, and controls the feeder and equipment immediately after being introduced into the incinerator by the feeder. Enabling the control of waste throughput in the furnace using a method that limits the range of steam flow fluctuations (or combustion gas temperature) and the combustion control parameters of solid waste throughout the incineration line .

  The present invention is a method for predictive evaluation of the heat load caused by waste treatment capacity, and when it is introduced by a feeder, it is materialized by itself after being introduced to a heating furnace and by effective combustion of the amount of waste. Measured when the product reaches the effective range of complete combustion before, after a while. Predictive evaluation of this heat load is done through evaluation of the steam flow generated by the boiler (or the temperature of the combustion gas). Before the measurement (or temperature measurement), waste is put on the grate in the combustion section. After a time corresponding to the movement of waste until it reaches the center of the grate.

  The evaluation of this steam flow (or combustion gas temperature) resulting from waste treatment capacity is based on a set of temperature and pressure sensor means located in the immediate vicinity of the feeder where waste enters the furnace grate. Done. The pressure sensor is located on the primary air inlet that is injected into the first part of the furnace grate (first section or first roll of grate). The temperature sensor is located on the lower deck or sidewall of the furnace, in the immediate vicinity of the first region of the combustion furnace. Thus, these sensors can measure the pressure and temperature in the first region of the combustion furnace, in the immediate vicinity of the feeder, with respect to the waste treatment capacity input by the feeder.

  The pressure of the primary air inlet injected below the first area of the furnace grate gives an image of the production capacity along with the rating. These pressures can be corrected by measuring airflow or measured again with constant airflow.

  The temperature of the gas measured on the lower deck or sidewall of the furnace in the immediate vicinity of the first area of the furnace grate gives an image of product quality, in particular flammability and moisture content. An outline of the generation processing capability is also given.

  The actual heat load of the waste is obtained when the waste is completely burned in the center of the combustion section of the grate, which continues very close to the first area of the furnace grate. This heat load causes the boiler to generate a constant steam flow (or combustion gas temperature) after a certain time required for the waste to reach the complete combustion section. The heat load can also be calculated from measurements of oxygen (or carbon dioxide) contained in the combustion gas if the amount of combustion air is known or constant.

  The present invention establishes a mathematical relationship between pressure and temperature measurements carried out in the immediate vicinity of the first zone of the furnace grate, and the waste from the grate to the combustion section A method which makes it possible to make a vapor flow (or combustion gas temperature) measurement after a time corresponding to the movement of

Therefore, this invention is a predictive evaluation method of the heat load produced | generated with the solid waste thrown into the heating furnace for incineration with a feeder. FIG. 1 is a functional diagram of the present invention showing measurements and measurement points in an elevation view of a furnace for incineration of solid waste. The present invention is divided into the following steps (see FIG. 1).
1. Projecting below the waste input on the furnace grate, in the part (2) near the feeder and in the part that overlaps the primary air inlet under the first area (3) of the grate, Measure the pressure of the part (1st part of the grate or the first roll) (1) as close as possible to the feeder.
2. Measure the temperature of the combustion gas in the part (4) in the immediate vicinity of the feeder on the higher part of the furnace or on the side walls, ie in the immediate vicinity of the waste input on the furnace grate.
3. Its characteristics are already 1. And 2. The steam flow (or combustion gas) generated from the boiler (5) after a certain time corresponding to the time required to reach the center of the grate in the combustion section (6) when waste is charged Temperature).
4). Establish a mathematical relationship between pressure, temperature, and steam flow (or combustion gas temperature) measurements.
5). Apply mathematical relationships to pressure and temperature measurements that occur simultaneously during the incineration process to allow calculation of an estimate of steam flow (or combustion gas temperature).

  As a result, the estimated steam flow (or combustion gas temperature) is used to control the combustion of the incinerator, especially from the input to the supply hopper to the discharge by the sluggish mover, which has a waste supply and transfer function. It can be used as input data for the control.

  Using only pressure and steam flow measurements (or combustion gas temperature) or only temperature measurements and steam flow (or combustion gas temperature) reduces the quality of the mathematical model that can be built, and the pressure / temperature data Note that this is a predictive evaluation with a larger mean error than the result of the tuple-based mathematical model.

  The mathematical relationship is the sum of pressure and temperature measurements and is measured by a coefficient that is the result of calculating the steam flow (or the temperature of the combustion gas).

  The method also includes an automatic and periodic update of these coefficients to take into account model variations over time. Fluctuations can occur due to sudden changes due to the nature of solid waste, but solid waste heating furnaces when setting parameters that affect changes in the incineration process, such as changes in the combustion air inlet and changes in steam flow This is also due to fluctuations in the operating state. This update is performed by a self-adaptive filtering technique related to signal processing, but can also be obtained by a training method depending on a neural network, or a verification method such as fuzzy logic. Figure 2 shows this algorithm, where Pi is a set of pressure measurement results, Ti is a set of temperature measurement results, SF is a steam flow (TCG or combustion gas temperature can be used), T is a time variable, and diff is The time corresponding to the movement time from the introduction of the waste into the grate portion to the arrival at the combustion portion is shown.

  By automatically updating this coefficient, a furnace model can be obtained, and this is simultaneously compared with the calculated value of the actually measured model, and online correction is made (see FIG. 2). This makes it possible to obtain a reliable model very easily.

  The present invention may be used in a factory digital control system method implementation or in a single device that measures and transmits an estimate of steam flow (or combustion gas temperature) by means of a standardized signal to the control system.

  In order to measure these values in the above method (1., 2. and 3.) or related by a data measurement system, take measurements in combination and associate with these data measurement systems, data acquisition and calculation By using a single device consisting of a unit, pressure sensor, temperature sensor, and steam flow sensor (or combustion gas temperature sensor), the manufacturer or owner of the solid waste incinerator will not affect the incineration process. Or it is possible to obtain the predicted value of this heat load (steam flow, combustion gas temperature, oxygen or carbon dioxide ratio, etc.) without changing the current control method for solid waste incinerators. It is a point to be done. This method using a single device of this kind is easier to implement.

  As a result of the structure of the method described above, in particular, automatic coefficient update by simultaneous comparison of predicted values of steam flow (or combustion gas temperature), model output of actual measured steam flow (or combustion gas temperature), temperature, pressure and Vapor flow (or combustion gas temperature) sensors do not require strict and periodic correction. The approximate result of the sensor is corrected by the nature of the measured coefficient calculation. As a result, the equipment using this method is durable and the maintenance cost is low.

It is a functional diagram of the present invention showing measurement and measurement points in an elevation view of a heating furnace for incineration of solid waste. It is a figure which shows the algorithm of the self-adaptive filtering technique regarding a signal processing.

Claims (5)

The amount of solid waste when the solid waste is introduced by the feeder onto the grate inside the incinerator, independent of the incinerator technology (grating heating rod push, roll use, vibration or other) A method for predictive evaluation of heat load,
Located on the furnace grate (part 1 in FIG. 1) where the waste is charged, near the feeder (part 2 in FIG. 1) and below the first area of the incineration grate Measure the primary air inlet pressure on the primary air inlet duct (part 3 in FIG. 1) and as close as possible to the feeder (first part of the grate or first roll) The pressure can be corrected with the measured air flow, or the first step is much more accurate than the result measured with a constant air flow;
A second measuring the temperature of the combustion gas on the high part or side wall of the furnace (part 4 in FIG. 1), very close to the feeder, very close to the part where the waste on the furnace grate is charged And the steps
After a time corresponding to the time required for the waste characterized in the first step and the second step to be introduced and arrive at the center of the grate in the combustion section (portion 6 in FIG. 1), The steam flow generated by the boiler is measured (part 5 in FIG. 1), and the measurement of the steam flow or the temperature of the combustion gas at this time leads to an equation for the heat load, which is the proportion of oxygen contained in the combustion gas or the A third step that can also be calculated by measuring the proportion of carbon;
Build a mathematical relationship between the measurement results of pressure, temperature and heat load (usually steam flow or combustion gas temperature), said mathematical relationship has a weighted coefficient, the result is the calculated heat load ( A fourth step which is the temperature of the steam stream or the combustion gas, or the proportion of oxygen or carbon dioxide in the combustion gas);
Fifth step to apply the mathematical relationship to the pressure and temperature measurements that occur simultaneously during the incineration process and to calculate an estimate of the heat load of the steam flow (normal steam flow or combustion gas temperature) A method characterized by five steps consisting of:   By only the pressure measurement as described in the first step of claim 1 and the measurement of the heat load (normal steam flow or combustion gas temperature) as described in the third step of claim 1, Or simply by measuring the temperature as described in the second step of claim 1 and the measured value of the heat load (normal steam flow or combustion gas temperature) as described in the third step of claim 1. The method of claim 1, wherein an alternative can be implemented by building a generalized mathematical model.   This is done by comparing real-time results with actual measurements and through self-adaptive filtering techniques linked to signal processing (Figure 2), or through training methods linked to neural networks, or even more experience. The weighted coefficients are automatically and periodically updated to take into account model variations over time leading to corrections in the line of correlation, such as through fuzzy logic, which is a type of dynamic method The method according to claim 1 or 2.   Evaluation value of heat load (temperature of steam or combustion gas or oxygen or carbon dioxide in combustion gas) and combustion control of incinerator, especially from introduction to feed hopper to discharge by slag remover 4. A method according to claim 1, characterized in that it leads to provide input data for the control of moving parts for supplying and transporting waste.   An apparatus comprising a data acquisition and calculation unit in which the method according to claim 1 is implemented.