FI119075B2 - Method, system and control unit for boiler injection - Google Patents

Description

Method, system and control unit for boiler injection

Background of the invention

The invention relates to power plants and in particular to steam power plants whose turbine is driven by hot steam.

Feed water flow control

It is important for the operation of the power plant that the supply of water to the boiler is as uninterrupted and secure as possible. Therefore, the water is stored in the feed water tank before the actual heating process. The purpose of the feed water tank is to ensure that there is water in the boiler cylinder in all situations. The volume of the boiler cylinder is not very large, which is why the water volume control of the cylinder must work properly and prevent, for example, the surface of the cylinder from falling below the so-called dry cooking limit. The disturbances result in a variation in power which causes changes in the pressure in the cylinder and thus in its pin-nanometer.

The feed water pump continuously supplies water to the cylinder. The control of the feed water flow is implemented in the prior art based on the surface height of the boiler cylinder. The goodness of previous adjustments has been assessed mainly by how well the surface of the boiler cylinder stays in place.

In one-point adjustment, the height of the cylinder water level is measured and the adjustment is performed according to the cylinder water level. In two-point control, the control is affected not only by the water level in the tank but also by the flow of feed water. In three-point control, the control is affected by the height of the cylinder water level, the steam flow from the cylinder and the feed water flow.

Traditionally, a three-point control has been used in a steam boiler. The known control systems are in themselves functional, but in practice they over-control or under-control the flow of feed water continuously, because in a power plant the time constants of such control are large. On average, prior art adjustments appear to give good adjustment results, but fluctuations during one cycle can be significant. The problem with known adjustments is the instability, oscillation and instability of the adjustment. i

Syringe flow control

In the power plant, the feed water is pumped from the feed water tank to the boiler cylinder. Water is led from the cylinder in a natural cycle to the cooling pipes of the furnace walls, where the generated steam is separated in a cylinder droplet separator. From there, the steam is directed to a multi-stage superheater, where the temperature is controlled between the distiller stages by injection coolers. Boiler feed water is used as spray water.

The purpose of the spraying is to maintain the desired final steam temperature and to dampen rapid temperature changes due to process disturbances. The control can be considered as one of the so-called critical controls, because the power of the boiler is largely determined by the steam temperature and the mass flow. Safe operation of the boiler also requires precise control of the steam temperature, as too rapid temperature fluctuations can significantly impair the durability of the steam piping. The turbine may also be damaged if the temperature changes too quickly. In addition, care must be taken to ensure that no water droplets enter the turbine, as these cause severe wear.

The boiler must have a sufficient number of superheaters so that it can also be operated at part load. In this case, the amount of steam must be increased with spray water. A situation in which the last syringe accounts for a significant proportion of the steam temperature control should be avoided. In this case, even the slightest error in the control is immediately visible at the final steam temperature.

Controlling the temperature of superheated steam is challenging due to long time constants and especially in bioboilers due to irregular fuel supply. For balancing the boiler plant, the injection control is as important as the cylinder surface adjustment. Vibrating spray control affects the life of the superheaters and, in extreme cases, shortens the life of the steam piping and turbine. Changes in the mass flow in the water balance are a significant disturbance to the boiler pressure control and thus to the fuel control and together these may reinforce the disturbance to the power plant process.

Brief description of the invention

The object of the invention is thus to develop a method and a system and control unit implementing the method so that the above-mentioned problems can be solved. The object of the invention is achieved by a method, a system and a control unit, which are characterized by what is stated in the independent claims. Preferred embodiments of the invention are the subject of dependent claims.

It is an object of the invention to provide a method for boiler injection. Another object of the invention is to provide a system for boiler injection. A third object of the invention is to provide a control unit for boiler injection.

The control method according to the invention converts the injection control into a mathematical model which is not parameter dependent. The control valves are non-linear. In particular, the spray control is non-linear.

According to one embodiment of the invention, the method: - measures the steam mass flow mh - calculates the energy flow per degree Qc - calculates the energy flow Q2 that should be added / decreased to the steam with the spray water to reach its desired final temperature - calculates the energy flow Qx before the superheater - calculates the spray water mass :

.where mv = spray water mass flow [kg / s] QV2 = energy flow [kJ / s] hv = spray water enthalpy [kJ / kg] - adjust the spray flow controller using the calculated spray water mass flow.

Temperature and pressure compensation can be used to measure mass flow. The mass flow measurement range may be limited depending on the power plant power. The amount of energy per degree Qc. Is calculated by the formula:

.where

Qc = energy flow per degree [kJ / s ° C] c = specific heat capacity of fresh steam [kJ / kg ° C] mh = mass flow of fresh steam [kg / s].

The energy flow Q2 is calculated by the formula:

.where Q2 = energy flow [kJ / s] T2 = temperature after syringe [° C]

Tr = structural temperature of the superheater [° C]

Qc = energy flow per degree [kJ / s ° C].

The energy flow 0i is thus obtained from the formula:

, where 0, = energy flow [kJ / s]

Tx = temperature before syringe [° C]

Tt = target steam temperature before the superheater [° C] 0C = energy flow per degree [kJ / s ° C]. The target steam temperature before superheater Tt is calculated by the formula:

where

Tt = target steam temperature before superheater [° C]

Tspa = active temperature controller setpoint [° C]

Tta = steam superheat degree [° C].

The obtained spray water mass flow mv is summed to the controller output and its additional value calculated from the difference value, which are further summed to the set value of the flow controller acting as a down-regulator.

According to an embodiment of the subject of the second invention, the system has means for implementing the steps according to the method for implementing the flow control.

According to an embodiment of the third object of the invention, the control unit is adapted to calculate the calculations according to the method for adjustment. The control unit is not system dependent. The control unit can operate in an existing automation system or independently, e.g. as a JAVA application.

The invention further relates to a method for updating a superheat rate table used for boiler injection, in which - the temperature equalizer output value is measured - the current actual superheat rate is calculated based on the equalizer output value - the calculated actual actual superheat rate is compared superheat rate table size, which are pairs of steam mass flow (x) and change in steam temperature in the superheater (y). The actual superheat rate can be calculated if necessary, for example if the value of the equalizer output is different from zero. The update teaches the adjustment what the superheater degree of superheating is at any given time. This is done by utilizing the output of the temperature correction controller. Deviating it from zero means that the specified superheat rate differs from the current actual superheat rate.

Brief description of the figures

The invention will now be described in more detail in connection with preferred embodiments, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic diagram of a power plant water-steam balance control and a single injection water control;

Figure 2A shows the structure and operation of the spray control of the superheaters;

Fig. 2B shows an example of calculating the superheat degree of the superheaters of the system of Fig. 2A;

Figure 3 shows the variation of feed water and fresh steam mass flows in conventional three-point control;

Figure 4 shows the variation of feed water and fresh steam mass flows in the balance control according to the invention;

Figure 5 shows the variation of the cylinder surface in a conventional three-point adjustment;

Figure 6 shows the variation of the cylinder surface in the balance adjustment according to the invention;

Figure 7 shows the variation of levels during the turbine trip;

Figure 8 shows the variation of the cylinder surface level during the turbine trip;

Figure 9 shows the amount of oil used during the turbine trip;

Figure 10 shows the variation of boiler power and feed water mass flow with conventional three-point control;

Figure 11 shows the variation of boiler power and feed water mass flow in the balance control according to the invention;

Fig. 12 shows a situation with conventional control and balance control according to the invention, in which the power of the plant is reduced overnight;

Figure 13 shows the variation of boiler power and injection rates with conventional control;

Figure 14 shows the variation of boiler power and injection rates in the balance control according to the invention;

Fig. 15 shows an example of variations in steam temperatures in conventional injection control and balance control according to the invention;

Fig. 16 shows an example of variations in the injection rates of the secondary syringe in the conventional injection control and the balance control according to the invention;

Fig. 17 shows an example of boiler flue gas O 2 levels in a conventional injection control and a balance control according to the invention;

Fig. 18 shows an example of the required maximum powers with conventional control and balance control according to the invention;

Fig. 19 shows an example of power differences with conventional control and balance control according to the invention;

Fig. 20 shows an example of boiler fuel power differences with conventional control and balance control according to the invention.

Detailed description of the invention

Referring to Figure 1, there is shown a schematic diagram of a power plant water-steam balance control and a single injection water control.

BOILER WATER-STEAM BALANCE ADJUSTMENT STRUCTURE ADJUSTMENT STRUCTURE

The surface adjustment of the cylinder 10 is based on the balance of the mass flow to and from the cylinder. At its core are two controllers, a cylinder surface controller 11 and a feed water flow controller 12. The actual process-influencing control is the surface controller output, which controls both the feed water valves 13 and the feed water pump 14 depending on the driving situation.

SURFACE CONTROL STRUCTURE

The cylinder surface adjuster 11 is measured by the height of the cylinder surface. The remote setpoint of the cylinder surface controller 11 is determined as a function of the pressure of the cylinder 10 by the following formula:

.where

Lsp = setpoint for cylinder surface adjuster [mm] p, = cylinder pressure [bar].

The surface controller 11 can be in either remote or local mode. In local mode, the operator can enter the desired setpoint. With Remote selection, the setpoint comes from the point pair table set according to the boiler characteristics. The surface controller 11 and the flow controller 12 operate in incremental mode. This means that the previous control calculated by the controller is subtracted from the previous control and this difference is added to the read-back control.

, where con = new control

Acon = control change conb = readback control

The read-back control, or conb, is set to zero each time it is executed, ie the control change is read directly as the controller output.

The control of the surface controller 11 is both maximum and minimum limited. When the difference value of the flow controller 12 is less than a certain process-specific value and the surface of the cylinder is greater than a certain value, the control of the surface controller 11 is limited to -0.03. The magnitude of the critical difference value, in turn, depends on the pressure in the cylinder 10 as follows:

when the cylinder pressure p,> 3 bar

when the cylinder pressure p, <3 bar.

When one or both of the control valves 13 are on the automatic and the subsequent shut-off valve is closed, the control of the surface controller 11 is limited to a maximum of zero for a certain time, for example after 300 seconds. In this case, the minimum of the surface controller 11 is also limited to zero, i.e. the controller does not adjust.

If the surface of the cylinder 10 is above a limit value, for example 350 mm, the output of the surface controller 11 is limited to -1. In this case, the valve is closed at a speed of 1% / run.

In a situation where there is no fire in the boiler, the feed water flow is more than 30 kg / s and the surface of the cylinder is less than 350 mm, the output of the surface controller 11 is limited to zero. The minimum control of the surface controller 11 is normally directly controlled by the flow controller 12.

FLOW CONTROLLER STRUCTURE

The flow controller 12 is always on the automaton when the surface controller 11 is on it. It is always in the remote mode, i.e. the operator cannot set the setpoint, but it comes through the calculation. The flow controller 12 directly measures the flow of feed water. The setpoint of the flow controller 12 is obtained by the following calculation. If the fire is in a boiler, the starting point for calculating the setpoint is the mass flow balance of the cylinder 10, i.e. what leaves the cylinder 10 and what enters it. If there is no fire in the boiler, only the feed water mass flow is calculated.

.where mlout = mass flow from the cylinder [kg / s] mth = mass flow of fresh steam after the superheaters [kg / s] ήιηγ = mass flow into the primary syringes [kg / s] mn2 = mass flow into the secondary syringes [kg / s] mup = mass flow from the cylinder exhaust [kg / s ].

From the mass flow from the cylinder 10 calculated above as well as from the mass flow to the cylinder 10, averages over a given period of time, for example a period of 15 minutes, are subtracted from each other. A small number is added to the calculation, the value of which depends on the difference value of the cylinder surface controller 11. If this difference value is greater than or equal to -120 mm, the value to be summed is 3 kg / s, if less than -120 mm, the value is 12 kg / s. It should be noted that the cut-off values and summation values may vary depending on the process in question. The formula is as follows:

.where ™ separation = difference between the averages of the mass flow from and to the cylinder corrected by additional water [kg / s] ™ echo = 15 min from the cylinder. average [kg / s] M / cain = 15 min entering the cylinder. average mlv = additional water (3 or 12) [kg / s].

Next, the average mass flow difference is subtracted from the instantaneous mass flow from the cylinder:

, where msp = flow controller setpoint [kg / s] mhul = mass flow from the cylinder [kg / s] ™ separation = difference [kg / s] corrected by the additional water averages of the mass flow from and to the cylinder.

The value obtained goes to the remote setpoint 12 of the flow controller. When the control valves are automatic, the minimum control is limited according to the following formula:

.where

Fconmm = minimum limit of flow controller control

Lcon = cylinder surface adjuster control.

The flow regulator 12 is forcibly controlled when both supply water control valves are manually controlled or when the surface of the cylinder 10 is higher than the upper limit, for example 280 mm. When the forced control of the flow controller 12 is on, the control of the controller is set to -1. This thus also passes as the minimum limit for the control of the surface controller 11. The purpose of the mass balance calculation is to keep the flows in the condensate and feed water circuit constant. This ensures even power to the turbine and generator and avoids unnecessary adjustments to the water-steam circuit.

SYRINGE CONTROL OF SYRINGES CONSTRUCTION OF HEATERS

Figure 2A shows the structure and operation of the spray control of the superheaters. Steam heating usually takes place in several superheaters 20 installed in series. These are usually referred to as primary, secondary and tertiary superheaters, depending on the direction of steam flow. The steam passes through the superheaters 20 all the way to the two pipelines (left and right). To ensure the balance of the lines, the boiler is usually run symmetrically so that both lines receive approximately the same heat output. The steam temperature control ensures that after the last superheater, the lines become steam at the desired temperature. In addition, the lines are often crossed so that from the right end of the previous manifold to the left end of the next manifold and vice versa. This improves the even superheating of the steam. The control thus consists of two identical entities (left and right steam line). The control of the syringes is implemented with cascade control, ie the control of the upper controller goes to the setpoint of the lower level controller.

DETAILED STRUCTURE OF SPRAY CONTROL

The spray controls work in the same way. Only the setpoint given by the operator to the upper level controller of the cascade is different. The operator sets the desired temperature after the superheater as a setpoint. The control of the upper regulator is limited to a suitable range depending on the maximum steam clay flow. This control is summed with a number that linearly depends on the difference between the setpoint of the upper controller and the measurement. Summation is performed only when the difference value exceeds a certain threshold value. In addition to this, the control is summed by the term obtained by starting from the energy balance of the injection. The starting point for the calculation is that the aim is to determine, both by measurements and by calculation, the amount of energy at which the final temperature of the steam reaches the set value set for it. In practice, therefore, the energy content of the steam is calculated before the last superheating step by injecting water into the steam.

The calculation is based on the measurement of the steam mass flow. In order to make the measurement as reliable as possible, temperature and pressure compensation is used for the flow measurement. The steam mass flow measurement is limited to a certain range depending on the power plant capacity. Multiplying the mass flow of steam by the specific heat capacity obtained from its plot gives the amount of energy per unit time that changes the temperature of the steam by one degree. The following formula is given:

,where

Qc = energy flow per degree [kJ / s ° C] c = specific heat capacity of fresh steam [kJ / kg ° C] mh = mass flow of fresh steam [kg / s].

Two calculations are performed for the energy flow per degree. Both are based on which energy flow should be added / decreased to the steam with the spray water in order to reach its desired final temperature. In addition to this, the function of the second is to ensure that the temperature of the steam does not exceed the structural temperature of the superheaters, which is specific to the superheater. For this calculation, a minimum limit can be given to Qc. This enhances the operation of the syringe.

The calculation is performed according to the following formula:

.where Q2 = energy flow [kJ / s] T2 = temperature after syringe [° C]

Tr = structural temperature of the superheater [° C]

Qc = energy flow per degree [kJ / s ° C].

The second calculation for the energy flow uses a sensor before the syringe to measure the steam temperature. In addition, the calculation takes the target steam value as the temperature obtained by subtracting the steam superheat rate from the active setpoint of the upper controller. It is a function of the steam mass flow, and depends on the structure of the superheater. The energy flow is thus obtained from the formula:

.where Q, = energy flow [kJ / s]

Tj = temperature before syringe [° C]

Tt = target steam temperature before superheater [° C]

Qc = energy flow per degree [kJ / s ° C]. The target steam temperature before the superheater is calculated by the following formula:

.where

Tt = target steam temperature before superheater [° C]

Tspa = active temperature controller setpoint [° C]

Tta = steam superheat degree [° C].

The energy flows obtained above are summed in the following calculation to obtain the total energy flow at which the energy of the steam must be changed in order to reach its target temperature. Since the steam temperature is changed with water syringes, the total energy flow must still be converted to a water mass flow using the energy content of the water, i.e. enthalpy, in the calculation. The spray water is taken from the boiler feed water. If the plant feed water temperature is almost constant, a fixed value can be used for its enthalpy. If, instead, the supply water temperature varies, the supply water temperature must be measured in order to calculate its energy content. The required spray water mass flow rate is given by the following formula:

.where mv = mass flow of spray water [kg / s]

Qh2 = energy flow [kJ / s] hv = enthalpy of spray water [kJ / kg].

The resulting spray water mass flow is summed to an additional term calculated from the controller output and its difference value, which are further summed to the remote setpoint of the flow controller acting as a down-regulator. The flow regulator outlet directly controls the spray water control valve in the range 0-100%. The spray water flow controller receives a temperature-compensated spray water flow measurement as a measurement. This measurement must be related to the position information of both the left and right injection valves of the superheater if the flow measurement is common to both sides.

INJECTION CONTROL DEGREE TEACHING INSTRUCTION

Syringe adjustments are based on mathematical models that water and fresh steam are known to behave. However, since the process is never ideal, in addition to models, controllers are needed that correct the models and parameters. For example, the superheat degree of superheaters changes not only as a function of the mass flow of steam, but also as a function of time, mainly due to fouling. The information obtained from the manufacturer on the degree of ignition may also differ from what it actually is.

Therefore, it is necessary to teach the control what the superheater degree of superheating is at any given time. This is done by utilizing the output of the temperature correction controller. Deviating it from zero means that the specified superheat rate differs from the current actual superheat rate. Since the control of the correction controller is a factor to be directly summed to the setpoint of the lower controller, the difference between the given and the actual superheat degree can be calculated directly from it. with a steam flow and update the correct superheat rate to the table. Teaching should be done slowly so that the values obtained are real and not due to momentary disturbances.

Teaching the superheat degree starts practically the opposite of control calculation. Now that the control of the temperature correction controller is known, it is possible to calculate the change in the temperature of the steam corresponding to the control. This change updates the superheat curve given during the commissioning phase of the control. The calculation formula is as follows:

.where ATh = change in steam temperature due to controller calculated water mass flow [C] mv = controller calculated water mass flow [kg / s] hv = injection water enthalpy [kJ / kg] mh = controller calculated water mass flow [kJ / kg] c = specific heat capacity of fresh steam [KJ / kgC]. In connection with the introduction of the control, the directional value pairs (x, y) of the superheaters have been given, which are thus the steam mass flow and the change in the steam temperature in the superheater. The determined range of steam mass flow is divided into sections so that each determined point is in the center of the section. There are four parts in the example, but their number and width can vary depending on the application. The points according to Figure 2B may be, for example, the following. 60, 120, 180, and 230 kg / s. The division is then made as follows: 30 kg / s <Vapor mass flow <90 kg / s 90 kg / s <Vapor mass flow <150 kg / s 150 kg / s <Vapor mass flow <210 kg / s 210 kg / s <Vapor mass flow < 250 kg / s.

From the result of the above formula, calculate the 30-minute average as well as the fresh steam flow. There are the same number of calculations as there are areas. When there is a change in the average of the temperature change, it taps the calculation in which the average of the temperature difference of the previous formula is added to the degree of output given by the curve. The formula is as follows:

,where

Ttu = new superheat rate of steam [C]

Ttv = old steam superheat rate [C] AThka = 30 min average of the steam temperature change caused by the controller control. This calculation is performed only in the area to which the current mass flow of steam belongs. This is shown in Figure 2B. If, for example, the mass flow of steam is 70 kg / s, it falls in the range of 30-90 kg / s in the example. Thus, the temperature change obtained from the calculation is added to the superheat degree of 40C ° corresponding to the average of its range. However, the newly calculated superheat rate does not transfer to the curve as it is, but is filtered as a first-order filter so that the change is calm.

Figure 3 shows the variation of feed water and fresh steam mass flows in conventional three-point control. When three-point control is used, a clear sine wave variation in the feed water mass flow is observed. The variation is up to 55 kg / s. The signal has a certain phase shift due to a process delay.

Figure 4 shows the variation of feed water and fresh steam mass flows in the balance control according to the invention. The new balance control does not show a clear sine wave variation in the feed water mass flow according to Fig. 3. The variation in this example is only 12 kg / s.

Figure 5 shows the variation of the cylinder surface in a conventional three-point adjustment. When three-point adjustment is used, a clear sine wave variation is observed in the surface of the cylinder. The cylinder surface variation is up to 275 mm.

Figure 6 shows the variation of the cylinder surface in the balance adjustment according to the invention. The new balance adjustment does not show the high sine wave variation in Figure 5 on the surface of the cylinder. The variation of the cylinder surface in this example is only 110 mm.

Figure 7 shows the variation of levels during the turbine trip. The valve before the turbine closes, stopping the steam mass flow. The pressure in the cylinder increases, causing the boiling to stop and the surface of the cylinder to decrease. Later, the start valve is opened, whereupon the steam pressure decreases, boiling occurs and the surface of the cylinder rises.

Figure 8 shows the variation of the cylinder surface level during the turbine trip. It can be seen from the figure that the surface of the cylinder varies during the turbine trip up to about 490 mm, but the surface of the cylinder remains under control throughout the trip and does not cause other trips. With conventional adjustment, the turbine strip always also caused the boiler strip.

Figure 9 shows the amount of oil used during the turbine trip. After the turbine strip, solid fuel cannot be used, so the boiler is heated with oil. This increases the cylinder pressure, stops boiling and lowers the cylinder surface. It can be seen from Figures 7-9 that the water / steam circuits according to the invention are also stable when running on oil and fuel cut-off. Figure 10 shows boiler power and feed water mass flow variation with conventional three-point control and Figure 11 shows boiler power and feed water mass flow variation in balance according to the invention. It can be seen from the figures how the range of the mass flow of the feed water is considerably smaller than in the conventional three-point control of Fig. 10. The vibration of conventional control increases, especially when using inhomogeneous fuels. The oscillation of the fuel supply is increased because it is used to compensate for the pressure variation due to the oscillation of the supply water.

Fig. 12 shows a situation with conventional control and balance control according to the invention, in which the power of the plant is reduced overnight. When driving at lower power, it is common for the cylinder surface to be more restless than when driving at high power. However, with the new balance control, this cylinder oscillation is fairly independent of plant power.

The cylinder surfaces are shown here as 10 min averages. With the old adjustment, a clear sine wave oscillation is caused here, which is caused by the adjustment itself. With the new control, this oscillation is considerably smaller and is mainly due to uneven fuel supply.

Figure 13 shows the variation of boiler power and injection rates with conventional control. Figure 14 shows the variation of boiler power and injection rates in the balance control according to the invention. In balance control, the primary goal is to keep the energy content of the steam at the desired value. The old control is based on direct steam temperature control. Variation in the amount of spray water affects the amount of steam produced and thus the boiler pressure control.

Figure 15 shows an example of variations in steam temperatures in conventional spray control and balance control according to the invention. It can be clearly seen from the figure that the variations in steam temperatures are clearly smaller with the new control than with the conventional control. Fluctuations in steam temperatures strain the superheater and steam pipes and affect the efficiency of the entire power plant.

Fig. 16 shows an example of variations in the injection rates of the secondary syringe in the conventional injection control and in the balance control according to the invention. For example, a spraying of 5 kg / s can correspond to about 2.5% of the boiler's output, so a lower spray rate improves the plant's efficiency.

Fig. 17 shows an example of boiler flue gases (V levels in conventional injection control and balance control according to the invention. Steam boiler water balance balancing is directly related to fuel volume control and again has an effect on boiler flue gas O 2 level and boiler efficiency.

Fig. 18 shows an example of the required maximum powers with conventional control and balance control according to the invention. The powers required by the balance control according to the invention are lower than the traditional control.

Fig. 19 shows an example of power differences with conventional control and balance control according to the invention when the variation of the feed water mass flow is ± 10 kg / s or ± 2 kg / s.

Fig. 20 shows an example of boiler fuel power differences with conventional control and balance control according to the invention. With conventional control, the variation of turbine power in the example is between 577.5 and 641.4 MW. With the new balance control, the corresponding power variation in the example is 603 to 615.9 MW. Thus, by means of the control according to the invention, it is possible to drive closer to the maximum power, whereby the losses of electrical power are also reduced. It is obvious to a person skilled in the art that with the development of technology the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above but may vary within the scope of the claims.

Claims (18)

Patent claims [corrected on 20.12.2011] 1. A method for boiler injection, in which: - measuring the steam mass flow in mh - calculating the energy flow per degree Qc - calculating the energy flow Q2 that should be added or reduced to the steam with the injection water to reach its desired final temperature - calculating the energy flow change before the superheater mv formula: , where mv = injection water mass flow [kg / s] Ql2 = energy flow [kJ / s] hv = injection water enthalpy [kJ / kg] - adjust the injection flow controller by means of a calculated injection water mass flow, where the flow controller forms the lower level controller of the cascade control to be used, the value of the output of the temperature correction controller after the fan forming the upper level controller of the cascade control, - calculating the change in steam temperature corresponding to the output of the temperature correction controller, - comparing the value of the temperature correction controller output with the value of the the actual superheat rate of the superheater as determined by the method, the method being further characterized by the steps of: in which, before comparing the actual superheat rate, to the degree of superheating previously used in the calculation: the change in steam temperature ATh caused by the temperature correction device calculated by the temperature correction device is calculated by the formula: , where ATh = change in water temperature due to temperature correction by the temperature correction device [° C] mv = water mass flow rate calculated by the temperature correction device [kg / s] hv = enthalpy of injection water [kJ / kg] mh = fresh steam mass flow rate [kg / s] c = fresh steam specific heat capacity [kJ / kg ° C] - calculate the average of the steam temperature change corresponding to the value of the temperature compensator output every 30 minutes, and - calculate the average of the fresh steam mass flow every 30 minutes, after which the superheat rate is superimposed, the fresh steam mass flow rate and the change in vapor temperature in the superheater so that the vapor mass flow rate is divided into sections where each specified point in the value pair is in the middle of the section, - update the superheat mass mass flow range for the calculated average steam mass flow rate. adjusting the average change in steam temperature corresponding to the control value of the temperature equalizer to the old superheat rate given by the superheat rate table. Method according to Claim 1, characterized in that the new degree of superheat Ttu of the steam is calculated by the formula: , where Ttu = new steam superheat rate [° C] Ttv = old steam superheat rate [° C] AThka = 30 min average of the steam temperature change caused by the temperature correction controller control. Method according to one of the preceding claims, characterized in that temperature and pressure compensation are used for measuring the mass flow. Method according to one of Claims 1 to 2, characterized in that the measuring range of the mass flow is limited depending on the power of the power plant. Method according to one of Claims 1 to 2, characterized in that the amount of energy per degree Qc is calculated by the formula: , where Qc = energy flow per degree [kJ / s ° C] c = specific heat capacity of fresh steam [kJ / kg ° C] mh = mass flow of fresh steam [kg / s], Method according to one of Claims 1 to 2, characterized in that the energy flow Q2 is calculated by the formula: , where Q2 = energy flow [kJ / s] T2 = temperature after syringe [° C] Tr = structural temperature of the superheater [° C] Qc = energy flow per degree [kJ / s ° C]. Method according to one of Claims 1 to 2, characterized in that the energy flow (^) is thus obtained from the formula: , where Qx = energy flow [kJ / s] Tx = temperature before syringe [° C] Tt = target steam temperature before superheater [° C] Qc = energy flow per degree [kJ / s ° C]. Method according to Claim 7, characterized in that the target steam temperature before the superheater Tt is calculated by the formula: where Tt = target steam temperature before superheater [° C] Tspa = active temperature controller setpoint [° C] Tta = steam superheat rate [° C] where Tta is a function of steam mass flow. Method according to one of the preceding claims, characterized in that the obtained spray water mass flow v is summed to an additional term calculated from the output of the controller and its difference value, which is further summed to the set value of the flow controller acting as a down-regulator. Patent krav [patentkrav 20.12.2011] 1. In the case of energy recovery and energy, the energy efficiency of the energy supply is reduced to the energy level of Qc by the energy supply capacity of the energy sector in the case of the energy supply to the energy supply. - the weight of the insoluble water mass is equal to: , där mv = energy input pressure [kg / s] QV2 = energy input [kJ / s] hv = energy input enthalpy [kJ / kg] - regulation of the energy regulator with the output of the energy regulator, kaskadregelringen - Mater värdet for temperaturkorrigeringsregulatorns output of efter överhettaren, vilken temperaturkorrigeringsregulator constitutes kaskadregelringens överordnade regulator, - calculates the ångans temperaturförändring of which corresponds to värdet for temperaturkorrigeringsregulatorns output of, - for comparing the from värdet for temperaturkorrigeringsregulatorns output of the calculated dåvarande the true överhettningsgraden with the överhett-ningsgrad Tta SOM used has at the calculation of the flow rate of the flow rate, and - the value of the flow rate of the flow rate is determined by the value of the temperature control of the flow rate, and the value of the flow rate is determined. e t e c k n a t av att det ytterligare omfattar steg för att man förrän att jämföra den verkliga överhettngradgraden med överhettnadgraden använd tidigare i beräkningen: - den av regulatorn baknadförandringen av ångans temperatur ATh for , where ATh = the temperature in the range of the water content of the regulator [kg / s] hv = the weight of the energy of the regulator [kg / s] hv = insprutningsvattnets entalpi [kJ / kg] mh = färsa ] c = operating specificity of the capacitance [kJ / kg ° C], - the value of the temperature is adjusted for 30 minutes or more by the value of the temperature adjustment of the current value, or - the value of the value is determined for 30 minutes - up to a maximum of a period of time equal to the capacity of the plant to which it is connected, in the case of a plant to which the temperature is set, mitt, - uppdateringen utförs i överhettningsgradstabellen i färskångans det flödesområde i vilket det beräk These methods are used for measuring the temperature of the ligand, the genome of which is used for measuring the temperature of the temperature of the fusion test. 2. For the purposes of paragraph 1, the provisions of this Regulation shall apply to the following forms: , then Ttu = angling rate [° C] Ttv = angling rate [° C] AThka = 30 min for the temperature setting of the control circuit. 3. The present invention provides for the application of a temperature control and mass compensation. 4. The method of claim 1 to 2, which is based on the weight of the mass of the effect of the kraft network effect. 5. An application is made to claims 1 to 2, which refer to the power supply per degree Qc of the formulation. , där Qc = energy flux per grad [kJ / s ° C] c = färskångans specifika värmekapacitet [kJ / kg ° C] mh = färskångans massflöde [kg / s], 6. For the purposes of claim 1 to 2, the terms of reference Q2 for energy Q2 are as follows: , for Q2 = energy flux [kJ / s] T2 = temperature after injection [° C] Tr = energy temperature [° C] Qc = energy flux per grad [kJ / s ° C]. 7. The method of claim 1 to 2, according to which the energy data Q1 is based on the formula, is as follows: , for Ql = energy flow [kJ / s] Tx = temperature for injection [° C] Tt = average temperature for cooling [° C] Qc = energy flow per degree [kJ / s ° C]. 8. For the purposes of claim 7, a reference is made to the following terms and conditions for the purposes of paragraph 7: then Tt = the temperature of the flow rate [° C] Tspa = the temperature control value of the flow rate [° C] Tta = the flow rate of the flow rate [° C] of the value of the flow rate. 9. The application of the present invention, the reverse charge of which is intended to be used as a means of regulating the use of a different type of regulator, the regulator of which is different from that of the regulator.