JP7157102B2 - Management device for biomass power generation equipment, biomass power generation equipment, method for calculating moisture content when wood chips are used as fuel - Google Patents

Description

The present invention relates to biomass power generation.

In order to reduce CO2 emissions for the prevention of global warming and improve the energy self-sufficiency rate for the realization of a sustainable society, renewable energy, especially woody biomass power generation, is expected to expand in Japan, which is rich in forest resources. there is As a patent related to biomass power generation, there is Patent Document 1 below.

In Patent Document 1 below, a weighing conveyor 13 is provided downstream of a supply hopper 12, and the weighing conveyor 13 measures the flow rate of biomass fuel supplied from the supply hopper 12 to the boiler.

Japanese Patent No. 5092822

As a management method for biomass power generation equipment, it is considered effective to manage power generation efficiency, which is the ratio of boiler heat input to power generation. At present, however, since the moisture content of the wood chips used as fuel cannot be specified, the heat input to the boiler cannot be calculated, and the power generation efficiency cannot be managed. In addition to managing power generation efficiency, specifying the moisture content of wood chips is also considered meaningful in terms of managing the remaining amount of wood chips.

SUMMARY OF THE INVENTION The present invention was completed based on the above circumstances, and an object of the present invention is to calculate the moisture content of wood chips used as fuel.

A management device for a biomass power generation facility includes a computing unit, and the computing unit determines the biomass power generation facility based on the weight of wood chips used as fuel for the biomass power generation facility and the amount of power generated by the biomass power generation facility. A fuel consumption rate is calculated, and based on the correlation with the fuel consumption rate, the used moisture content of wood chips used as fuel for the biomass power generation facility is calculated. The used moisture content is the moisture content when the wood chips are actually used as fuel (when used as fuel), such as when the wood chips are put into a hopper. With this configuration, the used moisture content of wood chips can be calculated based on the correlation with the fuel consumption rate.

Embodiments of the present invention may have the following configurations.
A period from when the remaining amount of chips in the chip storage is zero to when the wood chips received in the chip storage are used up and the remaining amount of chips becomes zero again is defined as a period of zero remaining amount. A correlation between the average moisture content of wood chips during the zero period and the average fuel consumption rate during the zero residual period may be used. The average moisture content in the period of zero remaining amount can be calculated from only the measured values without any assumptions, so there is an advantage that the accuracy is high. That is, it is possible to accurately specify the average used moisture content and obtain a highly accurate correlation. Therefore, it is possible to specify the used moisture content of wood chips with high accuracy by utilizing the high-accuracy correlation.

Embodiments of the present invention may have the following configurations.
The calculation unit calculates the lower heating value of the wood chip based on the calculated moisture content, calculates the heat input of the boiler based on the calculated lower heating value, and calculates the calculated heat input; The power generation efficiency of the biomass power generation equipment may be calculated based on the amount of power generated by the biomass power generation equipment. With this configuration, it is possible to specify the power generation efficiency of the biomass power generation equipment, which is effective in managing the biomass power generation equipment.

Embodiments of the present invention may have the following configurations.
The calculation unit may calculate the absolute dry fuel consumption rate, which is the ratio of the absolute dry weight of wood chips to the amount of power generated by the biomass power generation equipment, based on the fuel consumption rate and the moisture content. Absolute dry fuel consumption rate is an index for evaluating the amount of fuel purchased, so it is effective for evaluating business feasibility.

Embodiments of the present invention may have the following configurations.
The computing unit calculates the bone-dry remaining amount of wood chips on the day based on the bone-dry weight of the wood chips received on the day, the bone-dry weight of the wood chips used on the day, and the bone-dry amount of the wood chips on the previous day. The remaining amount of wood chips is calculated based on the absolute-dry remaining amount of wood chips on the day and the moisture content of the wood chips, and the remaining amount of wood chips is calculated based on the calculated remaining amount of wood chips and the lower calorific value of the wood chips. The amount of residual heat of the chip may be calculated. With this configuration, it is possible to accurately estimate the remaining amount of wood chips and the amount of residual heat, and it is possible to sufficiently manage the remaining amount of wood chips.

Embodiments of the present invention may have the following configurations.
A display unit may be provided, and the display unit may display at least one calculation result among calculation results by the calculation unit.

According to the present invention, it is possible to calculate the moisture content of the wood chips used as fuel.

Schematic configuration diagram of biomass power generation equipment in one embodiment of the present invention Chart summarizing measurement items for each process Power generation efficiency calculation flow Graph showing weight change of wood chips P Graph showing the relationship between fuel consumption rate and moisture content Graph showing changes over time in fuel consumption rate, moisture content, power generation efficiency, and absolute dry HR Graph showing the yearly time transition of the calculation result of the remaining amount of wood chips P and the actual inspection of the remaining amount Block diagram of management device Block diagram of the first calculation unit Block diagram of the second calculation unit Block diagram of the third calculation unit

<Embodiment>
1. Description of Overall Configuration of Biomass Power Generation Facility 10 FIG. 1 shows a schematic configuration diagram of a biomass power generation facility 10 to which the present invention can be applied. This biomass power generation facility 10 includes a boiler 21, a turbine 23, a generator 25, a condenser 27, a feedwater pump 29, a bag filter 31, a fly ash silo 33, an exhaust tower 35, and a fuel supply unit. 40 and are provided.

The biomass power generation facility 10 uses the wood chips P supplied from the fuel supply unit 40 as fuel to generate steam in the boiler 21 and supplies the generated steam to the turbine 23 . Then, when the turbine 23 rotates due to the supply of steam, the generator 25 directly connected to the turbine 23 generates power.

Further, the exhaust gas from the boiler 21 is disposed from the exhaust tower 35 after the fly ash contained in the gas is filtered out by the bag filter 31 .

The fuel supply unit 40 includes a chip storage 41 that stores wood chips P, an input crane 43 , a supply hopper 45 and a supply feeder 47 .

There are two types of wood chips P: cut chips and crushed chips. A cutting chip is a chip obtained by cutting wood with a cutter or the like. Crushed chips are chips obtained by crushing wood with a hammer or the like. The cutting tips are square and thick, while the crushing tips are elongated in the fiber direction.

The chip storage 41 is provided with three types of yards: a cutting yard 41A, a crushing yard 41B, and a mixing yard 41C. The cutting yard 41A is for storing cutting chips, the crushing yard 41B is for storing crushed chips, and the mixing yard 41C is for storing mixed chips obtained by mixing cutting chips and crushed chips.

The loading crane 43 is movable in the horizontal direction in FIG. The wood chips P stored in the chip storage 41 are thrown into the supply hopper 45 by the crane 43 . In this example, mixed chips are used as the fuel to be put into the supply hopper 45 .

The loading crane 43 is equipped with a load meter 43A to measure the weight [t] of the wood chips P loaded into the supply hopper 45 .

When the supply feeder 47 below the hopper is driven, wood chips P as fuel are supplied from the supply hopper 45 to the boiler 21 through the fuel pipe 49 .

The supply feeder 47 is of a screw type, and supplies wood chips P by rotating a screw 48 . A plurality of screws 48 may be provided in a direction orthogonal to the plane of FIG. 1 .

Next, the electrical configuration of the biomass power generation equipment 10 will be described. The biomass power generation facility 10 includes a crane control device 51 that controls the loading crane 43 and a management device 55 .

The management device 55 has a control function of the fuel supply section 40 and a management function of the biomass power generation equipment 10 . Specifically, as a control function of the fuel supply unit 40, the amount of wood chips P supplied to the boiler 21 is adjusted so that the difference between the measured value of the generator output and the main steam pressure and the target value becomes small. .

For example, when the measured values of the generator output and main steam pressure are lower than the target values, a command to increase the rotation speed V of the supply feeder 47 is sent. As a result, the rotation speed V of the supply feeder 47 increases, and the amount of wood chips P supplied to the boiler 21 increases. Therefore, the generator output and the main steam output can be brought closer to the target values.

As one of the management functions of the biomass power generation facility 10, the management device 55 performs trend management of the power generation efficiency eff0. The process of managing the wood chips P, which are the fuel of the biomass power generation equipment 10, will be described first, and then the method of calculating the power generation efficiency eff0 of the biomass power generation equipment 10 will be described.

2. Control process and measurement items for wood chips P <Accepting process>
The receiving step is a step of receiving the wood chips P into the chip storage 41 . As shown in FIG. 1, wood chips P are loaded on a truck and carried to biomass power generation equipment 10 . The truck yard 15 of the biomass power generation facility 10 is provided with a truck scale 15A and a moisture meter 15B as instruments for measuring the wood chips P brought in.

The truck scale 15A measures the weight of the truck on which the wood chips P are loaded. By subtracting the weight of the truck from the measured value of the truck scale 15A, the received weight [kg] of the wood chips P can be measured. Also, the received moisture content [%] of the wood chips P can be measured by the moisture content meter 15B. Thus, in the receiving step, two items of the wood chips P, "received weight" and "received moisture content", can be measured.

The received weight is the weight of the wood chips P when they are received, and the received moisture content is the moisture content of the wood chips P when they are received. The receiving time is when the wood chips P are received in the chip storage 41 .

<Storage process>
The storage step is a step of storing the wood chips P in the chip storage 41 . The received woody chips P are roughly divided into cutting chips and crushed chips, which are stored separately in yards 41A and 41B and dried naturally. The wood chips P from the yards 41A and 41B are picked up by the loading crane 43 and loaded into the mixing yard 41C.

At this time, by controlling the number of times the chips are picked up by the charging crane 43 and thrown into the mixing yard 41C, the ratio of cut chips and crushed chips can be adjusted to the desired ratio.

For example, when the number of times of inputting cutting chips and crushing chips is 1:1, the cutting ratio (ratio of cutting chips in mixed chips) is 50%. The two types of wood chips P introduced into the mixing yard 41C are used after being mixed in the mixing yard 41C.

<Input process (usage process)>
The charging crane 43 randomly picks up the wood chips P from the mixing yard 41C and supplies them to the supply hopper 45 . The wood chips P supplied to the supply hopper 45 are then sent to the boiler 21 by the supply feeder 47 .

A load meter 43A is installed on the loading crane 43, and the weight [kg] of the wood chips P loaded into the supply hopper 45 (weight used as fuel) can be measured. However, since it is difficult to install a moisture meter, the used moisture percentage [%] of the wood chips P cannot be measured. The used moisture content is the moisture content of the wood chips P when fuel is used (when thrown into the hopper).

The reason why it is difficult to provide the loading crane 43 with a moisture content meter is that the moisture content needs to be measured by an operator by extracting a sample from the wood chips P. This is because it takes too much time and effort to perform such work each time the machine is put in, and it is actually difficult.

Also, as an item associated with the input step, the amount of electric power generated [kWh] as an output by the chip fuel can be measured by the wattmeter 25A provided in the generator 25. FIG.

The weight of the wood chips P used can be measured by the load meter 43A as described above, and the power generation amount can be measured by the power meter 25A. Therefore, the fuel consumption rate HR representing the used weight [kg] consumed to obtain 1 kWh of generated power can be obtained from the used weight of the wood chips P and the generated power amount.

<Analysis of chip properties by an external organization>
The wood chips P are periodically sampled and analyzed for absolute dry calorific value and ash content by an external institution.

As described above, the management process of the wood chips P includes four processes: the receiving process, the storage process, the input process, and the property analysis. FIG. 2 shows measurement items of wood chips P in each step.

3. Calculation of Power Generation Efficiency eff0 and Trend Management The power generation efficiency eff0 of the biomass power generation facility 10 can be calculated in three steps S1 to S3 (see FIG. 3).

(S1) Calculation of used moisture content Uwout of wood chips P (S2) Calculation of lower heating value LHVout of wood chips P (S3) Calculation of power generation efficiency eff0

<About S1>
1. Change in moisture weight during storage in chip storage As shown in FIG. 4, the received weight Z1 of the wood chips P received in the receiving process is the sum of the absolute dry weight X and the received moisture weight W1. The absolute dry weight X is the dry weight (weight after drying) of the wood chips P, and the moisture weight W is the weight of water contained in the wood chips P.

Part of the moisture contained in the wood chips P evaporates or absorbs moisture during the storage period from the receipt in the chip storage 41 to the actual use as fuel. The used weight Z2 of the wood chips P becomes lighter by the amount Q of evaporation of moisture than when received, or becomes heavier by the amount of moisture absorbed.

"Q" in FIG. 4 indicates the amount of water evaporated during the storage period of the wood chips P, and "W2" indicates the weight of water used in the wood chips P. As shown in FIG. Even if the water evaporates, the absolute dry weight X does not change and remains constant.

4. Calculation of Moisture Percentage Used Uwout Focusing on Zero Remaining Period During the remaining zero period, the wood chips P received in the chip storage 41 are used up from the state where the remaining amount of chips in the chip storage 41 is zero, and the remaining amount of chips becomes zero again. It is the period until In other words, the period during which the remaining amount of chips in the chip storage 41 is changed from zero to zero, that is, after the wood chips P are received in the chip storage 41 with the remaining amount of chips being zero, all the chips are used up, and the amount of remaining chips becomes zero. It is the period until returning. The zero remaining amount period is, for example, several months to half a year.

Since the weighing scale during the zero remaining amount period is not affected by the remaining amount of chips in the chip storage 41, the following equations 1 and 2 hold for the entire period. In addition, the weight scale is the total weight.
Bone dry weight scale received = Bone dry weight scale used (1)
Used moisture weight scale = used weight scale - used dry weight scale = used weight scale - received dry weight scale (2)

Then, from the used moisture weighing scale obtained by the equation (2), the average used moisture content of the wood chips during the period when the remaining amount is zero can be obtained from the following equation (3).
Average percentage of moisture used during the period of zero remaining amount = Moisture weight scale used / Weight scale used (3)

The average used moisture content during the zero remaining period can be calculated from only the measured values without any assumptions, so it has the advantage of being highly accurate.

FIG. 5 is a graph showing the relationship between the average fuel consumption rate HR during the zero remaining amount period and the average moisture content used during the zero remaining amount period. This graph was obtained by conducting a survey multiple times (multiple periods) to examine the average moisture content and average fuel consumption rate during the same period, with the zero residual amount period as one unit. From the obtained data, when the correlation between the average moisture content during the period of zero remaining amount and the average fuel consumption rate HR during the period of zero remaining amount is obtained, the correlation straight line (primary approximation straight line) indicated by the solid line shown in FIG. 5 is obtained. Using the correlation straight line indicated by the solid line in FIG. 5, the used moisture content Uwout of the wood chips P can be expressed by Equation (4) using the fuel consumption rate HR as a variable.

Moisture content used = 0.4431 x HR - 0.1940 (4)

The fuel consumption rate HR can be obtained from the weight of wood chips P used, which can be measured by the load meter 43A, and the amount of power generated by the generator 25, which can be measured by the wattmeter 25A, as shown in Equation 5. That is, it can be determined using only measurable quantities.
Fuel consumption rate HR = weight of wood chips P used / amount of power generated [kg/kWh] (5)

The relationship between correlation and power generation efficiency eff0 is supplemented . In the woody biomass power generation facility 10 for which data was collected, since efforts are being made to improve efficiency, the average moisture content and average fuel consumption are grouped by the period during which high-efficiency operation was performed and the period other than that. When the rate HR is correlated, the correlation straight line indicated by the dotted line in FIG. 5 is obtained, and the correlation is further improved.

The absolute value of the moisture content Uwout differs by about 1% between the high-efficiency operation period and other periods, but the amount of change (slope) with respect to the fuel consumption rate HR is substantially the same. For the correlation line, the characteristics of the solid line may be used without distinguishing between the high efficiency operation period and other periods, or the dashed line characteristics corresponding to the high efficiency operation period and other periods may be used. You may choose to use it.

Further, as shown in the equation (4), the used moisture content Uwout of the wood chips P is expressed by a linear expression with the fuel consumption rate HR as a variable. Since the fuel consumption rate HR, which is a variable, can be obtained in real time from the measured values of the used weight and generated power, the used moisture rate Uwout of the wood chips P can also be calculated in real time.

<About S2>
S2 calculates the lower heating value LHVout of the wood chips P using the used moisture content Uwout of the wood chips P calculated in S1. Among the calorific value obtained by burning the fuel (wood chips), the calorific value including the latent heat of condensation obtained when the water vapor generated in the combustion gas is condensed is called the higher calorific value. The calorific value that does not include latent heat is called the lower calorific value.

It is known that the relationship of the following formula 6 generally holds between the lower heating value LHV of the wood chips P and the moisture content Uw.
LHV = primary term x Uw + constant term (6)

The constant term is the lower calorific value LHV when the moisture content is zero, that is, the absolute dry calorific value LHVm of the wood chips P. In the present embodiment, the constant term is calculated from the following 7 equations from the analysis data of the wood chips P (bone dry calorific value LHVm, ash content Ua) measured by an external analysis agency.
Constant term = LHVm/(1-Ua) (7)

In Equation 6 above, when Uwout=100%, LHV=the amount of heat absorbed by water. Therefore, the relationship of heat absorption amount of water=primary term+constant term is established.

Therefore, the first-order term can be calculated by the following 8 equations.
First-order term = (heat absorption amount of water - constant term) (8)
The first order term<0.

As the heat absorption amount of water, 539 kcal/kg, which is the latent heat when water vaporizes, is used.

As described above, the first-order term and the constant term can be obtained. Therefore, by substituting the used moisture content Uwout of the wood chips P obtained in S1 into Equation 6, the lower calorific value LHVout of the wood chips P can be calculated. I can. LHVout is the lower calorific value when wood chips P are used as fuel.

<About S3>
S3 calculates the power generation efficiency eff0 of the biomass power generation equipment 10 using the lower calorific value LHVout of the wood chips P calculated in S2. The power generation efficiency eff0 is the efficiency of converting thermal energy (heat input of the boiler) possessed by the wood chips P into electrical energy.

The heat input of the boiler 21 can be obtained from the following equation 9 using the weight of wood chips P used and the lower heating value LHVout.
Boiler heat input = weight of wood chips P used x lower calorific value LHVout [kcal] (9)

The power generation efficiency eff0 can be obtained from the following equation 10 using the amount of power generated by the generator 25 and the amount of heat input to the boiler 21 .
Power generation efficiency eff0 = power generation [kWh] x 860 / heat input of boiler [kcal] (10)
Note that 860 is a unit conversion factor.

In steps S1 to S3, the power generation efficiency eff0 of the biomass power generation facility 10 can be obtained. The power generation efficiency eff0 can be obtained as data in units of days and hours. The trend of power generation efficiency eff0 can be managed from changes in power generation efficiency eff0.

In the present invention, it is possible to calculate the used moisture content Uwout of the wood chips P, which has been difficult in the past. It has become possible.

Therefore, the power generation efficiency eff0 can be estimated from the power generation amount, and the power generation efficiency can be managed in the same manner as in thermal power generation facilities using fossil fuels. From the above, we can expect management that is directly linked to business feasibility, such as deterioration management of equipment, early detection of signs of abnormality due to changes in operating conditions, and confirmation of improvement effects of equipment operation.

FIG. 6 shows the time transition of the fuel consumption rate HR, the water content Uwout used, and the power generation efficiency eff0 calculated by the above steps S1 to S3 over a period of one year.

5. Regarding the fuel consumption rate ratio The ratio of the fuel consumption rate to the standard is defined as the fuel consumption rate ratio, and its value is obtained.
HRr = HR/HRs (11A)
HRr is the fuel consumption rate ratio, HR is the fuel consumption rate, and HRs is the reference value of the fuel consumption rate.

As the reference value of the fuel consumption rate, it is preferable to use the planned value of the power generation equipment 10 or the average value of the zero remaining amount period. In this example, the reference value for the fuel consumption rate is calculated according to the following equation using the planned value for the amount of power generated per day, the planned value for the weight of chips used, and the like.

Uwout is the moisture content used at that time, LHVout is the lower heating value LHV at the moisture content Uwout used, and effs0 is the standard power generation efficiency.

Standard power generation Es0 [kWh/d] = Generator rated output [kW] x 24 [h] (11B)
Standard heat input Qs0 [Mcal/d] = Es0 x 860/1000/effs0 (11C)
Standard working weight Fs0 [t/d] = Qs0/LHVout (11D)
HRs [kg/kWh] = Fs0 x 1000/Es0 (11E)

Then, if the fuel consumption rate ratio HRr obtained by formula 11A is greater than 1, that is, if HR > HRs, it is determined that the amount of fuel used is greater than the standard and the power generation efficiency eff0 is worse than the standard power generation efficiency effs0. I can.

Conversely, if the fuel consumption rate ratio HRr obtained by formula 11A is less than 1, that is, if HR < HRs, the amount of fuel used is less than the standard, and the power generation efficiency eff0 is better than the standard power generation efficiency effs0. I can judge.

The reference value HRs is a reference value for the weight of wood chips P required to generate 1 [kWh] of electric power. The weight of the wood chips P used takes on a different value if the lower heating value LHV changes, so the reference value HRs needs to be calculated for each LHV.

6. Indicators for evaluating business feasibility The following relationship exists between the power generation efficiency eff0, the chip's lower calorific value LHV, and the fuel consumption rate HR.
eff0×LHV×HR=constant (12)
The constant is 860 in the unit system of LHV (kcal/kg) and HR (kg/kWh).

In the biomass power generation equipment 10, the weight of the wood chips P used and the amount of power generated are measurable items, so from Equation 5, the fuel consumption rate HR can be measured in real time. Therefore, the value of "860/HR", that is, the value of "eff0×LHV" can be calculated from the fuel consumption rate HR.

Since the LHV of the fuel is generally constant in a thermal power plant that uses LNG as fuel, the power generation efficiency eff0 can be specified after all if the HR can be calculated.

However, in a woody biomass power generation facility using woody chips P as fuel, LHV changes greatly due to fluctuations in the amount of water retained in the woody chips P during storage in the chip storage .

According to the present invention, the used moisture content Uwout can be specified from the fuel consumption rate HR, so that the lower heating value LHV can be specified, and the power generation efficiency eff0 can also be specified.

In order to evaluate the business feasibility of the biomass power generation facility 10, it is necessary to manage the fuel purchase amount. From Equation 12, the fuel consumption rate HR corresponding to the amount of fuel used is expressed by Equation 13.
HR=860/LHV/eff0 (13)

In a thermal power plant with little change in LHV, the power generation efficiency eff0 and the fuel consumption rate HR are inversely proportional, and if eff0 is managed, the amount of fuel purchased can be managed.

On the other hand, in a wood biomass power generation facility, LHV changes greatly due to fluctuations in the amount of water retained in wood chips P. Therefore, even if the power generation efficiency eff0 improves, if the amount of LHV decrease is large, the product of eff0 and LHV will be small. As a result, HR, or fuel purchases, will increase.

From the above, in the woody biomass power generation equipment 10, management of the power generation efficiency eff0 alone cannot manage the fuel purchase amount, and the business feasibility cannot be evaluated.

Bone-dry HR (bone-dry fuel consumption rate) is used as an index for evaluating business feasibility, that is, for evaluating the amount of fuel purchased. Absolute dry HR represents the absolute dry weight (wood weight) of wood chips P consumed to generate 1 kWh of electricity, and is defined by the following equation.

Absolute dry HR (HRz) [kg/kWh] = Absolute dry weight / amount of power generated
= weight used x (1 - moisture content used) / amount of power generated
= Fuel consumption rate HR x (1 - Moisture content used) (14)

Since the absolute dry weight of the wood chips P at the time of receipt and the absolute dry weight at the time of use are the same, the amount of fuel purchased can be managed regardless of the moisture weight of the wood chips P by using the absolute dry HR.

For example, if the standard power generation amount per day is Es0 [kWh/d], the absolute dry weight used per day is Formula 15.
Bone dry weight used in one day = Bone dry HR (HRz) x Standard power generation Es0/1,000 [t/d] (15)

If the moisture content Uws is used as a reference at the time of fuel purchase, the amount of fuel purchased can be calculated and evaluated by converting the absolute dry weight to the reference moisture content Uws using Equation 16.
Standard moisture content Uws conversion weight = Absolute dry weight used per day / (1-Uws) (16)

Figure 6 shows the annual time transition of power generation efficiency and absolute dry HR. In FIG. 6, the upper thick line indicates the temporal transition of "power generation efficiency", and the lower thick line indicates the temporal transition of "absolutely dry HR". If LHV is constant, absolute dry HR should decrease as power generation efficiency eff0 increases, but this is not necessarily the case. This indicates that absolute dry HR must be managed to evaluate the amount of fuel purchased.

7. Management of Remaining Amount of Chip Storage The bone-dry weight of wood chips P (=wood weight) is expressed by Equation (17).
Absolute dry weight of wood chips P=weight of wood chips P×(1−moisture content Uw) (17)

Since the bone-dry weight is not affected by the moisture weight, the bone-dry remaining amount on the day is the bone-dry remaining amount of the wood chips P from the previous day, the received bone-dry weight of the wood chips P, and the bone-dry weight of the wood chips P used. Based on the weight and the following formula 18, the absolute dry remaining amount of wood chips P on the day is calculated.
Absolute dry weight on the day = Absolute dry weight on the previous day + Accepted absolute dry weight - Used absolute dry weight (18)

Further, the remaining amount of wood chips P for the day is calculated based on the following equation 19 from the absolute dry remaining amount and the used moisture content Uwout for the day.
Remaining amount of wood chips on the day = Remaining amount of absolute dryness on the day/(1-Uwout) (19)

The amount of residual heat of the wood chips P is calculated from the following equation 20 using the remaining amount and the lower calorific value LHV for the day.
Remaining heat amount = remaining amount x lower heating value LHVout (20)

The amount of chips stored in the chip storage 41 must be managed based on the amount of heat. In the past, the volume was visually measured at the end of the month and converted to weight by multiplying it by the assumed bulk specific gravity, which required a lot of labor.

In the present invention, since it is possible to calculate the used moisture content Uwout of the wood chips P, it is possible to calculate the used absolute dry weight from the used weight of the wood chips P and the used moisture content Uwout based on Equation 17. can. Therefore, it is possible to obtain the amount of wood chips P remaining in the chip storage 41 for the day and the amount of residual heat.

FIG. 7 shows the yearly transition of the remaining amount calculation result according to the present invention and the remaining amount actual inspection result visually measured at the end of the month. The remaining amount calculation results and the remaining amount inspection results are generally in agreement, and it is evaluated that the remaining amount calculation can be used.

In addition, since the remaining amount is calculated using the used moisture content Uwout as shown above, if there is an error in the used moisture content Uwout, it will be accumulated in the remaining amount calculation result and the remaining amount error will increase. In FIG. 7, since the error between the remaining amount calculation result and the remaining amount actual inspection result is small, it can be evaluated that the error of the used moisture content Uwout calculated according to the present invention is small.

As described above, the remaining amount of wood chips P and the amount of residual heat can be estimated with high accuracy, and sufficient remaining amount of wood chips P can be managed. From the above, management that is directly linked to business feasibility becomes possible, such as fuel procurement management and business feasibility improvement by checking the drying conditions in the chip storage.

8. Regarding the management device 55,
As shown in FIG. 1 , the management device 55 includes an arithmetic section 100 , a storage section 150 , a display section 160 and an input section 170 . The storage unit 150 is for storing data, the display unit 160 is for displaying data, and the input unit 170 is for input by the administrator. The data stored in the storage unit 150 includes various data for calculating the used moisture content Uwout and the power generation efficiency eff0, such as the data of the correlation straight line shown in FIG.

FIG. 8 is a block diagram of the calculation unit 100. As shown in FIG. The computing section 100 includes a first computing section 110 , a second computing section 120 and a third computing section 130 .

The power generation amount, the used weight of the wood chips P, the received weight of the wood chips P, and the received moisture content of the wood chips P are input to the calculation unit 100 as signals for calculation. Incidentally, the amount of power generated can be measured by the power meter 25A of the generator 25. FIG. The used weight of the wood chips P can be measured by the load meter 43A of the charging crane 43. FIG. The received weight of the wood chips P can be measured by the truck scale 15A. The received moisture content of the wood chips P can be measured by the moisture content meter 15B.

The first calculator 110 calculates the used moisture content Uwout of the wood chips P based on the signal for calculation.

As shown in FIG. 9, the first calculator 110 has an HR calculator 110A and a moisture content calculator 110B.

The HR calculator 110A obtains the fuel consumption rate HR of the biomass power generation equipment 10 based on the amount of power generated and the weight of the wood chips P used. Specifically, it is obtained from the above-described formula 5.

The used moisture content calculator 110B calculates the used moisture content Uwout of the wood chips P. As shown in FIG. Specifically, based on the fuel consumption rate HR of the biomass power generation equipment 10, the used moisture content Uwout of the wood chips P is calculated from the above four equations.

As shown in FIG. 10, the second computing unit 120 computes the power generation efficiency eff0, the fuel consumption rate ratio HRr, and the absolute dry HR based on the moisture content Uwout used, the weight of the wood chips P used, and the amount of power generated. do.

As shown in FIG. 10, the second calculation unit 120 includes an LHV calculation unit 120A, a boiler heat input calculation unit 120B, a power generation efficiency calculation unit 120C, an HR calculation unit 120D, a setting unit 120E, a fuel consumption rate ratio calculation unit 120F, and It has an absolute dry HR calculator 120G.

The LHV calculation unit 120A calculates the lower calorific value LHVout of the wood chips P using the used moisture content Uwout of the wood chips P calculated by the first calculation unit 110 according to the above 6 equations.

The boiler heat input calculation unit 120B calculates the heat input of the boiler 21 from the above equation 9 based on the lower heating value LHVout of the wood chips P and the weight of the wood chips P used.

The power generation efficiency calculation unit 120C calculates the power generation efficiency eff0 from the above equation 10 based on the amount of heat input to the boiler 21 and the amount of power generated.

The HR calculator 120D obtains the fuel consumption rate HR of the biomass power generation equipment 10 based on the amount of power generated and the weight of the wood chips P used.

The setting unit 120E calculates the reference value HRs of the fuel consumption rate HR based on the lower heating value LHV of the wood chips P calculated by the LHV calculation unit 120A.

The fuel consumption rate ratio calculator 120F calculates the fuel consumption rate ratio HRr from the above equation 11A based on the calculated value of the fuel consumption rate HR calculated by the HR calculator 120D and the reference value HRs.

The absolute dry HR calculation unit 120G calculates the absolute dry HR (HRz) from the above equation 14 based on the calculated value of the fuel consumption rate HR calculated by the HR calculation unit 120D and the used moisture content Uwout.

The second calculation unit 120 may display the calculated data of each value on the display unit 160 . For example, the power generation efficiency eff0, the fuel consumption rate ratio HRr, and the absolute dry HR may be calculated on a daily basis, and the data may be displayed in a graph or the like with the horizontal axis as the time axis. The calculation cycle and display cycle of these data are not limited to daily units, but may be hourly units, half-day units, or several-day units.

As shown in FIG. 11, the third computing unit 130 includes a received absolute dry weight computing unit 130A, a used absolute dry weight computing unit 130B, a current absolute dry mass computing unit 130C, a previous day absolute dry remaining storage unit 130D, and a current absolute dry mass computing unit 130D. remaining amount calculation unit 130E, LHV calculation unit 130F, and residual heat amount calculation unit 130G.

The received absolute dry weight calculator 130A calculates the received absolute dry weight of the wood chips P from the received weight of the wood chips P and the received moisture content Uwin based on the above equation (17).

The used absolute dry weight calculator 130B calculates the used absolute dry weight of the wood chips P from the used weight of the wood chips P and the used moisture content Uwout based on the above equation (17).

The bone-dry remaining amount calculation unit 130C for the current day calculates the following from the previous day's bone-dry remaining amount of wood chips P, the received bone-dry weight of the wood chips P, and the used bone-dry weight of the wood chips P, based on the above equation 18. to calculate the absolute dry remaining amount of wood chips P on the day.

The remaining amount calculation unit 130E for the current day calculates the remaining amount of the wood chips P for the current day from the absolute dry remaining amount of the wood chips P for the current day and the used moisture content Uwout based on the above equation (19).

The LHV calculation unit 130F calculates the lower heating value LHVout of the wood chips P using the used moisture content Uwout of the wood chips P from Equation 6 above.

The residual heat amount calculation unit 130G uses the remaining amount of wood chips P for the day and the lower calorific value LHV to calculate the residual heat amount of the wood chips P from the above equation (20).

The third calculation unit 130 may display the calculated data of each value on the display unit 160 . Specifically, daily data of the absolute dry remaining amount, remaining amount, and residual heat amount of the wood chips P may be displayed in a graph or the like with the horizontal axis as the time axis.

<Other embodiments>
The present invention is not limited to the embodiments explained by the above description and drawings, and the following embodiments are also included in the technical scope of the present invention.

In the above embodiment, the average used moisture content during the zero remaining amount period was calculated from Equation 3. The average lower heating value during the zero remaining amount period may be calculated based on the average used moisture content during the zero remaining amount period. Further, based on the calculated average lower heating value, the average heat input of the boiler during the zero remaining amount period may be calculated. Then, the average power generation efficiency of the biomass power generation equipment during the zero remaining amount period may be calculated based on the average heat input of the boiler during the zero remaining amount period and the average power generation amount during the zero remaining amount period. If the remaining amount is zero period, each value can be calculated only by the actual measurement value, so a highly accurate value can be obtained.

In the above embodiment, the correlation between the moisture content used and the fuel consumption rate was obtained based on the actual data of the average moisture content used during the period with zero residual amount and the average fuel consumption rate during the period with zero residual amount (correlation line in FIG. 5 ).
The method of determining the correlation between the used moisture content and the fuel consumption rate is not limited to the method exemplified in the embodiment (method focusing on the zero remaining amount period), but may be determined from actual data of other periods. Further, the correlation between the used moisture content and the fuel consumption rate is not limited to linear approximation, and may be curve approximation or the like. Also, the correlation data is not limited to being held as a formula, and may be held as a reference table.

10 biomass power generation equipment 21 boiler 23 turbine 25 power generator 40 fuel supply device 43 crane 45 supply hopper 47 supply feeder 48 screw 51 crane control device 55 management device 100 calculation unit 110 first calculation unit 120 second calculation unit 130 third calculation unit

Claims (7)

A management device for a biomass power generation facility,
a computing unit;
a storage unit,
A zero remaining amount period is defined as a period from when the remaining amount of chips in the chip storage is zero to when the wood chips received in the chip storage are used up and the remaining amount of chips becomes zero again,
The storage unit stores data of the correlation between the average moisture content of wood chips during the period of zero remaining amount and the average fuel consumption rate during the period of zero remaining amount,
The average moisture content is data obtained by dividing the total weight of moisture used, which is calculated by subtracting the total weight of absolute dry weight received from the total weight of wood chips used in the period of zero remaining amount, by the total weight of wood chips used,
The total absolute dry weight received is data calculated by subtracting a value obtained by multiplying the total weight of wood chips received during the zero residual period by the received moisture content from the total received weight of wood chips during the zero residual period,
The average fuel consumption rate is data calculated from the total weight of wood chips used and the total amount of power generated during the period of zero remaining amount,
The calculation unit is
The fuel consumption rate of the biomass power generation equipment is calculated from the weight of wood chips used as fuel for the biomass power generation equipment and the amount of power generated by the biomass power generation equipment, and the remaining amount is stored in the storage unit. Based on the correlation between the average moisture content of wood chips in the zero period and the average fuel consumption rate in the zero remaining amount period, the moisture content of wood chips used as fuel for the biomass power generation facility when used as fuel. is calculated from the fuel consumption rate . The biomass power generation facility management device according to claim 1 ,
The calculation unit is
Calculate the lower calorific value of the wood chip based on the calculated moisture content,
Calculate the heat input of the boiler based on the calculated lower heating value,
A management device for a biomass power generation facility that calculates power generation efficiency of the biomass power generation facility based on the calculated heat input amount and the power generation amount of the biomass power generation facility. The biomass power generation facility management device according to claim 1 or claim 2 ,
The calculation unit calculates the absolute dry fuel consumption rate, which is the ratio of the absolute dry weight of wood chips to the amount of power generated by the biomass power generation facility, based on the fuel consumption rate and the moisture content. management device. The biomass power generation facility management device according to any one of claims 1 to 3 ,
The calculation unit is
Based on the bone-dried weight of wood chips received on the day, the bone-dried weight of wood chips used on the day, and the bone-dried remaining amount of wood chips on the previous day, calculating the bone-dry remaining amount of wood chips on the day,
calculating the remaining amount of wood chips based on the calculated absolute dry amount of wood chips on the day and the used moisture content of the wood chips;
A management device for a biomass power generation facility, which calculates the residual heat amount of wood chips based on the calculated remaining amount of wood chips and the low-order calorific value of wood chips. The biomass power generation facility management device according to any one of claims 1 to 4 ,
Equipped with a display,
The management device of the biomass power generation facility, wherein the display unit displays at least one calculation result among calculation results by the calculation unit. A biomass power generation facility comprising the management device according to any one of claims 1 to 5 . A method for calculating the moisture content used when wood chips are used as fuel,
A zero remaining amount period is defined as a period from when the remaining amount of chips in the chip storage is zero to when the wood chips received in the chip storage are used up and the remaining amount of chips becomes zero again,
a first step of creating data on the correlation between the average moisture content of the wood chips during the zero remaining amount period and the average fuel consumption rate during the zero remaining amount period;
Using the correlation data created in the first step, the moisture content used when wood chips used as fuel for biomass power generation equipment are used as fuel is calculated from the fuel consumption rate when wood chips are used as fuel. a second step;
The average moisture content is data obtained by dividing the total weight of moisture used, which is calculated by subtracting the total weight of absolute dry weight received from the total weight of wood chips used in the period of zero remaining amount, by the total weight of wood chips used,
The total absolute dry weight received is data calculated by subtracting a value obtained by multiplying the total weight of wood chips received during the zero residual period by the received moisture content from the total received weight of wood chips during the zero residual period,
The average fuel consumption rate is data calculated from the total weight of wood chips used and the total amount of power generated during the zero remaining amount period.
Method for calculating the moisture content used when wood chips are used as fuel.

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