JP4267352B2 - Gas supply method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for optimally operating gas supply. More specifically, the present invention secures a stable gas supply, and at the same time, reduces gas production costs at a manufacturing plant based on gas demand forecasts to achieve optimum costs. The present invention relates to a method for determining the production amount and supplying gas.
[0002]
[Prior art]
Conventionally, the amount of gas that is produced at multiple factories and supplied to consumers is determined by the consumer's consumption. If the consumer's consumption fluctuates, the amount of delivery at each plant also varies accordingly. . The reason for this variation is that a so-called pressure control (PC) delivery system is used in which the pressure in the gas supply line from each factory to the consumer is adjusted to be constant. That is, the high-pressure main line, which will be described later of the gas supply line, is extremely high, for example, 3-4 MPa (megapascals) so that the gas supply is not interrupted even if the gas delivery from each factory is temporarily stopped due to a power failure or the like. Kept in pressure. Therefore, when the consumer's consumption increases and the pressure of the high-pressure trunk line decreases, the gas delivery amount from each factory is immediately increased to adjust the pressure of the high-pressure trunk line to be constant. The In other words, the outlet pressure at each factory is always kept constant. Also, some factories supply gas using a so-called flow control (FC) delivery system that adjusts the flow rate of the gas supplied to the high-pressure trunk line to a constant level, and other factories use the PC delivery system. In some cases, a PC-FC delivery system for supplying gas is used (see, for example, Patent Document 1).
[0003]
With reference to FIG. 9, the gas supply system from each manufacturing site to a consumer is demonstrated. FIG. 9 is a block diagram schematically showing the gas supply system. In FIG. 9, the first and second manufacturing plants 101 and 102 produce gas and send it to the high-pressure main line 110 in which the high-pressure state is maintained. The high-pressure main line 110 is connected to the medium-pressure A gas conduit network 111 via a plurality of high-pressure governors 103a to 103c that lower the high pressure to the medium pressure A. The intermediate pressure A gas conduit network 111 is connected to the intermediate pressure B gas conduit network 112 via a plurality of intermediate pressure A governors 104 a to 104 d that reduce the intermediate pressure A to the intermediate pressure B. The holders 105a and 105b are typically installed in parallel with one or more medium pressure A governors 104a to 104d connecting the medium pressure A gas conduit network 111 and the medium pressure B gas conduit network 112. Valves are provided at the front and rear. The holders 105a and 105b can store gas from the intermediate pressure A gas conduit network 111 and release it to the intermediate pressure B gas conduit network 112 by opening and closing the valve. Due to this function, the holders 105a and 105b release the stored gas when the consumer's consumption increases, and when the consumer's consumption decreases, the holders 105a and 105b store the surplus gas and rapidly increase the consumption of the consumer. Mitigate the effects of major fluctuations. The medium pressure B gas conduit network 112 is connected to the low pressure gas supply conduit network 113 via a plurality of medium pressure B governors 106a to 106f that lower the medium pressure B to a low pressure. The low-pressure gas supply conduit network 113 is connected to the consumer 201, and the gas produced at the first and second manufacturing plants 101 and 102 is sent to the consumer 201 at a low pressure and consumed. Further, the medium pressure A gas and the medium pressure B gas conduit network 112 are also sent to the consumers 202 and 203 for consumption from the medium pressure A gas conduit network 111 and the medium pressure B gas conduit network 112, respectively.
[0004]
[Patent Document 1]
JP 2000-265184 A
[0005]
[Problems to be solved by the invention]
However, the first and second manufacturing sites 101 and 102 have manufacturing costs corresponding to the gas manufacturing amounts, respectively, and there are optimum manufacturing amounts for reducing these manufacturing costs. The manufacturing cost will vary if the delivery amount or production amount of the first and second factories 101 and 102 varies. Here, in order to explain the production cost and the optimum production amount, the gas production process will be briefly described.
[0006]
First, the liquefied LNG taken out from the storage LNG (Liquid Natural Gas) tank by the LNG pump is vaporized by a vaporizer using seawater pumped by the seawater pump (for example, a Tri-X type vaporizer). Supplied. The LNG gas vaporized in the LNG tank is supplied after being compressed by a BOG (Boil Off Gas) compressor. At this time, it may be further compressed by a BOG booster and supplied. The LNG gas supplied in this way is mixed with LPG separately taken out from an LPG (Liquid Petroleum Gas) tank by an LPG pump to adjust the amount of heat, and sent to the consumer as city gas. Here, it is normal that a plurality of gas delivery lines are provided for each manufacturing site, and there are cases where the presence or absence of heat amount adjustment and the delivery calorie value are different for each line. .
[0007]
In such a manufacturing process, power costs such as various pumps and compressors, heat adjustment costs, steam costs, water costs, and the like are intertwined in a complicated manner, and a gas manufacturing cost corresponding to the manufacturing amount is determined. For example, a plurality of LNG pumps are usually installed, and necessary numbers are sequentially activated according to the production amount. The LNG pump has the best power consumption efficiency when operated in the rated state, but the power consumption efficiency decreases when operated in the partial load state. For example, when operating three LNG pumps in the rated state, if the production volume is increased slightly, the fourth LNG pump must be started. In that case, all four units are operated in a partial load state. Become. Furthermore, if the production volume is increased and the four LNG pumps are operated in the rated state, the power consumption efficiency will be improved again. However, if the production volume is further increased, the fifth LNG pump will be activated, and the power load efficiency will be similarly increased. Deteriorate. Therefore, the operating cost varies depending on the number of activated LNG pumps. Depending on the amount of production, the production cost may be high or low. In other words, if there is an optimum production amount range for suppressing production costs and a production amount range in which the production cost is high for the manufacturing site, and the operation can be performed within the optimum production amount range, electricity for gas production can be obtained. Consumption can be kept low.
[0008]
When each manufacturing plant manufactures gas by the PC delivery method described above, the consumption of consumers changes from moment to moment, so the pressure of the high-pressure trunk line also changes, and the manufacturing of each manufacturing plant adjusts this pressure to a constant level. In order to adjust the amount, the production amount also varies accordingly. Therefore, it is difficult for a manufacturing factory that manufactures gas by the PC delivery method to manufacture gas only within the above-mentioned range of the optimal manufacturing amount. In addition, when each manufacturing plant manufactures gas by the PC-FC transmission method, the manufacturing plant manufactured by the FC transmission method can manufacture the gas only within the range of the optimum production amount. Similarly, it is difficult for a manufacturing factory that manufactures a gas to produce a gas only within the range of the optimum production amount. In addition, the time period and the day of the week when the power unit price of the power itself supplied to each factory is reduced, such as the night time period, are set, but according to the conventional example as described above, such a power unit price is low. It is also difficult to reduce manufacturing costs by using time zones and days of the week.
[0009]
Furthermore, during periods of high gas demand such as in winter, the gas demand per unit time zone is the largest throughout the year (hereinafter referred to as the maximum demand). As described above, when each manufacturing plant supplies gas by the PC sending method or the PC-FC sending method, the manufacturing plant that manufactures the gas by the PC sending method has the above-mentioned maximum demand in order to stably supply the gas. Gas production capacity capable of meeting the maximum demand is required in the time period indicating the quantity. Accordingly, each manufacturing facility has to have a gas production capacity equal to or greater than the maximum demand.
[0010]
Therefore, the object of the present invention is to ensure stable gas supply by systematically managing the gas main line pressure with respect to the expected gas demand, and at the same time, to estimate the gas production cost at the factory as the gas demand forecast. It is to provide a method for determining the production amount so as to reduce the cost based on the optimal cost.
[0011]
[Means for Solving the Problems and Effects of the Invention]
In order to achieve the above object, the present invention has the following features.
A first invention is a gas supply method in which a manufacturing plant supplies gas to a consumer via a supply line,
A supply line pressure management step for setting a time at which the gas pressure in the supply line should be maximized and a maximum pressure target value at that time so that the gas storage amount in the supply line is maximized at a predetermined time; The gas pressure of the supply line reaches the maximum pressure target value at the time set in the supply line pressure management step, and the gas pressure of the supply line is allowed for the supply line in all time zones divided every predetermined time unit. A production amount setting step for setting a gas production amount for each time unit in the factory so as to change within the set pressure range.
[0012]
As described above, according to the first aspect of the invention, the gas pressure in the supply line is set so that the gas storage amount in the supply line is maximized at a predetermined time, instead of making the gas pressure in the supply line constant. By providing the time to be maximized and the maximum pressure target value at that time, gas can be produced and stored by a predetermined time, and the production amount can be determined in consideration of the production cost of the factory.
[0013]
The second invention is an invention subordinate to the first invention,
Furthermore, the demand line prediction step includes a demand amount prediction step for obtaining a demand demand for each time unit by predicting the gas demand amount of the consumer in advance for each predetermined time unit, and the supply line pressure management step is obtained in the demand amount prediction step. In order to maximize the gas storage volume in the supply line during a time period when the predicted demand is relatively small, the time when the gas pressure in the supply line should be maximized and the maximum pressure target value based on the predicted demand And set.
[0014]
As described above, according to the second aspect of the present invention, the gas pressure in the supply line is not made constant, but the gas storage amount in the supply line is maximized in a time zone in which the predicted demand is relatively small. By setting the time when the gas pressure of the supply line should be maximum based on the predicted demand and the maximum pressure target value at that time, it is possible to build and store gas according to the predicted demand The production amount can be determined in consideration of the production cost.
[0015]
The third invention is an invention subordinate to the first or second invention,
Furthermore, a gas supply operation step of operating gas supply at the manufacturing site using the gas production amount set in the production amount setting step is included.
[0016]
According to the third aspect of the invention, the manufacturing site can manufacture and supply gas by using the manufacturing amount in consideration of the manufacturing cost of the manufacturing site.
[0017]
The fourth invention is an invention subordinate to the third invention,
Furthermore, a pressure simulation step for predicting the gas pressure in the supply line for each time unit in advance based on the predicted demand amount obtained in the demand amount prediction step and the gas production amount set in the production amount setting step, and a pressure Check that the gas pressure predicted in the simulation step is within the allowable pressure range for the supply line gas pressure in all time periods and meets the maximum pressure target set in the supply line pressure management step in advance. The gas supply operation step uses the gas production amount set in the production amount setting step and confirmed in advance in the pressure confirmation step, and operates the gas supply in the factory.
[0018]
As described above, according to the fourth aspect of the present invention, the actual value of the gas pressure is limited to the limit of the pressure range allowed in the supply line when the gas is actually supplied by predicting the gas pressure of the supply line in advance. Therefore, the operation of increasing and decreasing the gas delivery rate so as not to deviate from the pressure range can be prevented from occurring unexpectedly and frequently, and the production amount can be stably operated at the factory. . Further, since it is possible to detect that the actual value has deviated from the predicted gas pressure, it is possible to perform feedback control on the gas pressure predicted in advance.
[0019]
A fifth invention is an invention subordinate to the second to fourth inventions,
The maximum pressure target value set in the supply line pressure management step is set to the upper limit within the allowable pressure range at the start time of the time zone in which the predicted demand amount obtained in the demand amount prediction step is relatively large. .
[0020]
As described above, according to the fifth invention, when there is a time period in which there is a large amount of demand that exceeds the gas production capacity of the factory in winter, the demand amount for each time unit is predicted in advance, and the demand amount By setting the gas production amount so as to increase the pressure of the supply line in preparation for a time zone with a large amount of gas, it is possible to make a gas reservoir using the line pack effect. Therefore, the gas supply supplementing the gas production capacity of the factory can be stably performed. This can be dealt with without increasing the gas production capacity of each factory and without installing a new gas storage facility such as a holder, thereby preventing an increase in production cost due to new capital investment.
[0021]
The sixth invention is an invention subordinate to the fifth invention,
The supply line pressure management step further sets the minimum pressure target value to the lower limit within the pressure range allowed in the supply line at the time when the time period in which the predicted demand obtained in the demand prediction step is relatively large ends. The production amount setting step further sets the minimum pressure target value at the time when the time period when the predicted demand amount set in the supply line pressure management step relatively increases the gas pressure of the supply line ends. In addition, the amount of gas produced per unit of time at the factory is set.
[0022]
As described above, according to the sixth invention, when there is a time zone in which there is a large amount of demand that exceeds the gas production capacity of the factory in winter or the like, the demand amount for each time unit is predicted in advance, and the demand amount In order to set the gas production volume so as to increase the pressure of the supply line in preparation for the time zone when there are many times, and to set the gas production volume so that the gas pressure of the supply line becomes the lower limit at the time when the time zone ends, the line The gas built up by the pack effect can be used most effectively.
[0023]
A seventh invention is an invention subordinate to the second to fourth inventions,
The maximum pressure target value set in the supply line pressure management step is set to the upper limit within the pressure range allowed in the supply line at the time when the time zone in which the unit price of power supplied to the manufacturing plant is relatively low ends. .
[0024]
As described above, according to the seventh invention, when the demand amount for each hour is predicted in advance, and there is a margin for the maximum demand amount for which the gas production capacity of the factory is predicted in the summer, etc., the above production By setting the gas production volume so that the pressure of the supply line rises at a time when the unit price of the power supplied to the station is relatively low, the gas using the line pack effect is set at a time when the unit price of power is low. You can make a buildup. Therefore, it is possible to reduce the gas production cost at the manufacturing plant.
[0025]
The eighth invention is an invention subordinate to the seventh invention,
The supply line pressure management step further sets a minimum pressure target value at the lower limit within the pressure range allowed in the supply line at the start of a time zone in which the unit price of power supplied to the factory is relatively low, In the production volume setting step, the production line is further configured so that the gas pressure of the supply line changes the minimum pressure target value at the start of the time zone when the unit price of power set in the supply line pressure management step is relatively low. Sets the gas production volume for each time unit.
[0026]
As described above, according to the eighth invention, when the demand amount for each hour is predicted in advance, and there is a margin for the maximum demand amount for which the gas production capacity of the factory is predicted in summer, etc., the above production Set the gas production volume so that the pressure of the supply line becomes the lower limit at the start of the time zone when the unit price of power supplied to the station is relatively low, and increase the pressure of the supply line during the time zone By setting the gas production amount to the maximum, it is possible to store gas most effectively using the line pack effect in the time zone when the unit price of electricity is low.
[0027]
A ninth invention is an invention subordinate to the first to fourth inventions,
The maximum pressure target value at the time when the gas pressure of the supply line set in the supply line pressure management step should be maximum is set according to the season.
[0028]
As described above, according to the ninth invention, the difference in demand due to the season such as the winter when there is a large amount of demand and the summer when the demand is small, or the difference in the unit price of the electricity due to the season such as the summer when the electricity rate is high. Accordingly, the transition of the gas pressure in the supply line can be managed, and an appropriate gas supply according to the season can be operated.
[0029]
A tenth invention is an invention dependent on the second to fourth inventions,
The demand amount prediction step is characterized in that a plurality of parameters are taken into consideration for the day for which the predicted demand amount is obtained, and the predicted demand amount is obtained by using the gas demand amount data in the past days similar to the parameter.
[0030]
As described above, according to the tenth invention, the predicted demand amount is determined with reference to past demand results similar to those parameters in consideration of a plurality of parameters such as weather, temperature, humidity, day of the week, and seasons. Therefore, an accurate demand amount can be predicted.
[0031]
An eleventh invention is an invention subordinate to the first to fourth inventions,
Furthermore, the data collection step for collecting data for calculating the gas production cost at the manufacturing site, and the manufacturing at the manufacturing site so that the manufacturing cost is relatively low based on the data collected in the data collection step. A candidate value group determining step for determining a candidate value group for the quantity, and the production amount setting step sets a gas production amount for each time unit at the factory from the candidate value group determined in the candidate value group determination step.
[0032]
As described above, according to the eleventh aspect of the invention, the gas flow rate can be controlled so as to reduce the gas production cost at a plurality of factories, instead of making the gas pressure in the supply line constant.
[0033]
A twelfth invention is an invention subordinate to the eleventh invention,
The candidate value group determined in the candidate value group determining step includes a production amount value corresponding to an inflection point at which the manufacturing cost turns from a decrease to an increase.
[0034]
As described above, according to the twelfth aspect, it is possible to control the gas production amount of the manufacturing plant so as to operate at an advantageous power unit price in the vicinity of the optimum point so as not to increase the cost. If it does so, the method of operating gas supply optimally can be provided by determining a suitable production amount so that gas manufacturing cost may be reduced.
[0035]
A thirteenth invention is an invention dependent on the first to fourth inventions,
Furthermore, the data collection step for collecting data for calculating the gas production cost at the manufacturing site, and the manufacturing at the manufacturing site so that the manufacturing cost is relatively low based on the data collected in the data collection step. A candidate value group determining step for determining a candidate value group for the quantity, and the supply line pressure management step has a predetermined pressure range with the maximum pressure target value at the upper limit within the pressure range allowed in the supply line. In the production amount setting step, the first gas production amount in which all the gas production amounts for each time unit at the factory are selected from the candidate value group so that the gas pressure of the supply line changes the maximum pressure target value and , Gas production per unit of time at the factory so that the upper limit of the pressure range allowed by the supply line is reached at the time when the gas pressure of the supply line should be maximum Setting the second gas production volume.
[0036]
As described above, according to the thirteenth aspect, the gas production volume for creating and storing gas by a predetermined time is selected from candidate values with relatively low production costs, and the range of the maximum pressure target value is changed. It is possible to determine the gas production amount that takes into account the production cost of the manufacturing plant and the gas production amount that maximizes the gas storage amount that reaches the upper limit of the allowable pressure range with respect to the maximum pressure target value.
[0037]
A fourteenth invention is an invention subordinate to the thirteenth invention,
The gas supply further includes a gas production amount selection step of calculating a production cost of each gas in the first and second gas production amounts set in the production amount setting step, and selecting a gas production amount having a low production cost. In the operation step, the gas supply at the manufacturing site is operated using the gas production amount selected in the gas production amount selection step.
[0038]
As described above, according to the fourteenth aspect of the present invention, the gas production amount considering the production cost of the manufacturing plant and the production cost of the gas production amount maximizing the gas storage amount are compared, and the gas production amount is highly economical. Can be operated and the gas can be supplied by the manufacturing plant.
[0039]
The fifteenth invention is an invention subordinate to the thirteenth invention,
In the production amount setting step, the second gas production amount is selected from a group other than the candidate value group for a time zone before a certain time prior to the time when the gas pressure of the supply line should become maximum, and for the other time zones Select from the candidate value group.
[0040]
As described above, according to the fifteenth aspect, it is possible to determine the gas production amount that maximizes the gas storage amount while minimizing the time zone in which the production cost of the manufacturing plant is not taken into consideration.
[0041]
The sixteenth invention is an invention subordinate to the thirteenth invention,
In the supply line pressure management step, the time at which the gas pressure should be maximized is set to the time at which the time zone in which the unit price of power supplied to the manufacturing plant is relatively low ends.
[0042]
As described above, according to the sixteenth aspect, it is possible to set the gas production amount using a time zone in which the unit price of the power supplied to the factory is relatively low, and the line pack effect can be set in the time zone. The amount of gas storage used can be maximized.
[0043]
A seventeenth invention is an invention subordinate to the thirteenth invention,
The supply line pressure management step further has a predetermined range at a lower limit within the pressure range allowed in the supply line at the start of a time zone in which the unit price of power supplied to the factory is relatively low. The minimum pressure target value is set, and the production amount setting step further sets the first gas production amount so that the gas pressure of the supply line changes the minimum pressure target value, and the gas pressure of the supply line is The second gas production amount is set so as to reach the lower limit within the pressure range allowed in the supply line at the time when the unit price is relatively low.
[0044]
As described above, according to the seventeenth aspect, the gas production volume is set so that the pressure of the supply line becomes the lower limit at the start of a time zone in which the unit price of power supplied to the manufacturing plant is relatively low. By setting the gas production volume so as to increase the pressure of the supply line during the time period, the gas production volume that maximizes the time period when the unit price of power supplied to the factory is relatively low It can be set, and the gas can be stored most effectively using the line pack effect.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A gas supply system according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram schematically showing the gas supply system.
[0048]
In FIG. 1, first and second factories 1 and 2 produce gas and supply amounts X and Y (Nm, respectively). ^Three / H) is sent to the high-voltage main line 10 in which the high-pressure state is maintained. The delivery amounts X and Y of the first and second factories 1 and 2 are controlled by the central command room 7, respectively. The first and second factories 1 and 2 inform the central command room 7 of various data to be described later.
[0049]
The high-pressure main line 10 is connected to a medium-pressure A gas conduit network 11 via a plurality of high-pressure governors 3 a to 3 c that lower the high pressure to a medium pressure A. The high-voltage main line 10 takes into consideration a main line pack 14 described later.
[0050]
The intermediate pressure A gas conduit network 11 is connected to the intermediate pressure B gas conduit network 12 via a plurality of intermediate pressure A governors 4 a to 4 d that reduce the intermediate pressure A to the intermediate pressure B. The holders 5a and 5b are typically installed in parallel with one or more medium pressure A governors 4a to 4d connecting the medium pressure A gas conduit network 11 and the medium pressure B gas conduit network 12, Valves are provided at the front and rear. The holders 5a and 5b can store gas from the intermediate pressure A gas conduit network 11 and release it to the intermediate pressure B gas conduit network 12 by opening and closing the valve. Due to this function, the holders 5a and 5b release the stored gas when the consumer's consumption increases, and when the consumer's consumption decreases, the holders 5a and 5b store the surplus gas and rapidly increase the consumption of the consumer. Mitigate the effects of major fluctuations.
[0051]
The medium-pressure B gas conduit network 12 is connected to the low-pressure gas supply conduit network 13 via a plurality of medium-pressure B governors 6a to 6f that lower the intermediate pressure B to a low pressure. The low-pressure gas supply conduit network 13 is connected to the consumer 21, and the gas produced at the first and second factories 1 and 2 is sent to the consumer 21 at a low pressure and consumed. Further, the medium pressure A gas and the medium pressure B gas conduit network 12 are also sent from the medium pressure A gas conduit network 11 and the medium pressure B gas conduit network 12 to the consumers 22 and 23 for consumption. Hereinafter, the consumption of gas consumed by these consumers 21 to 23 is referred to as demand.
[0052]
Next, the main line pack 14 will be described. The main line pack 14 indicates the gas stored in the entire geometric volume of the high-pressure main line 10. The gas capacity stored in the main line pack 14 varies depending on the pressure of the high-pressure main line 10. By using the main line pack 14, when the demand is large, the pressure is reduced to supply gas to the medium pressure A gas conduit network 11, and when the demand is small, the pressure is increased. Gas is stored in the entire geometric volume of the high-pressure main line 10. Here, storing or supplying the gas to the main line pack 14 means that the pressure of the high-pressure main line 10 increases or decreases, but the PC sending method for keeping the pressure of the high-pressure main line 10 constant is not performed. Shall. Therefore, if the demand amount fluctuates, the line pressure fluctuates, and the gas is stored or supplied to the main line pack 14, whereby the fluctuation of the demand amount can be absorbed to some extent. The function of storing gas in the high-pressure main line 10 in this way is called a line pack effect.
[0053]
However, the main line pack 14 has a limited amount and not all of them are used. Although it is not necessary to keep the pressure of the high-pressure main line 10 constant, the minimum pressure required for gas supply (hereinafter referred to as the minimum pressure) and the pressure of the withstand pressure upper limit value (hereinafter referred to as the maximum pressure) This is because it is necessary to maintain a predetermined range of pressure in between.
[0054]
Next, the central command room 7 will be described. The central command room 7 is installed in a department such as a central security command section, for example, and is connected to the first and second manufacturing plants 1 and 2 via a communication line or the like. The central command room 7 receives various data from the first and second factories 1 and 2 and instructs the optimum production amount of gas at the first and second factories 1 and 2. Therefore, the central command room 7 is specifically provided with a general computer system including communication equipment.
[0055]
Next, a process for determining an optimum production amount range in the central command room 7 will be described. First, the central command room 7 collects data for calculating gas production costs at the first and second factories 1 and 2. The contents of the data include LNG tank calorie, LPG tank calorie, LNG, which vary depending on factors such as component composition, as well as the equipment performance data such as various pumps and compressors that have been determined in advance, scheduled maintenance, etc. Examples include BOG delivery patterns related to gas pressure in the tank, seawater temperature, and the like. Note that the facility performance data includes restrictions or constraint conditions such as the minimum operation amount and the maximum operation amount. Data as described above is collected at the first and second factories 1 and 2 and transmitted to the central command room 7.
[0056]
Next, the central command room 7 performs the first and second operations by performing a predetermined calculation on the manufacturing cost corresponding to the gas delivery amount finally delivered to the consumer based on the collected data. Calculated for each manufacturing site 1 and 2. In this calculation, various data are inputted so as to satisfy the above constraint conditions, and the heat amount adjustment cost corresponding to the delivery amount is calculated, but here only the result is illustrated, and the detailed contents thereof are described. Description is omitted.
[0057]
FIG. 2 is a graph exemplifying a power unit price unit curve obtained by the above-described calculation. Note that the graph shown in FIG. 2 does not take into account the increase / decrease in manufacturing cost due to a time period or day of the week when the power unit price is low.
[0058]
In FIG. 2, the vertical axis represents gas 1 m. ^Three Unit price of electricity for manufacturing (Unit: Yen / Nm ^Three ) And the horizontal axis is the delivery amount (unit: Nm ^Three / H). Referring to FIG. 2, the delivery amount is about 220,000 (Nm ^Three / H) and about 360000 (Nm ^Three / H), it is possible to find an inflection point at which the unit price of electric power changes from a decrease to an increase. If this inflection point is exceeded, the unit price of electric power will increase. Therefore, in order to optimally operate the gas supply so that the gas production cost is reduced, it is necessary to operate in consideration of this inflection point. .
[0059]
For example, the delivery amount is about 220,000 (Nm ^Three / H) is cheaper than the unit price of electricity when the output amount is about 260000 (Nm ^Three / H) or more, if the gas is produced in accordance with the delivery amount during this period, the production cost becomes high, and the production amount becomes an inappropriate value. Therefore, the central command room 7 optimizes the delivery amount that can be manufactured at an advantageous power unit price near the inflection point for each of the first and second factories 1 and 2 so that the delivery amount does not enter between them. Set as a candidate value for the send amount. Here, a plurality of candidate values are set, for example, 320,000 to 360,000 (Nm ^Three A value having a predetermined range such as / h) may be used.
[0060]
The process for setting the candidate value of the optimum delivery amount for each of the first and second factories 1 and 2 is performed by the central command room 7, but the first and second factories 1 and 2 are set. However, each of the candidate values may be set by collecting data and performing calculations. In that case, the respective candidate values determined in the first and second factories 1 and 2 are transmitted to the central command room 7 via the communication line.
[0061]
Next, in the central command room 7, the candidates at the first and second factories 1 and 2 are set so that the total production amount produced at the first and second factories 1 and 2 is equal to the demand amount. Appropriate values are selected from the values to determine the production quantities corresponding to the first and second factories 1 and 2. In the central command room 7, pressure dynamic analysis of the high-pressure trunk line 10 is performed in consideration of various parameters, and the production quantities thereof are determined. Hereinafter, with reference to FIG. 3, the process for determining the production amount performed in the central command room 7 will be described. FIG. 3 is a flowchart for explaining the process for determining the production amount performed in the central command room 7.
[0062]
In FIG. 3, the central command room 7 schedules the above-mentioned production amount in advance as one unit for 24 hours from 7 am to 7 am the next morning. First, the central command room 7 predicts the gas demand amount on the day on which the production amount plan is made (step S1). In forecasting the demand amount, the forecast demand amount is obtained in units of one hour by referring to the past demand amount results in consideration of the weather, temperature, humidity, day of the week, season, etc. of the day.
[0063]
Next, in the central command room 7, a past similar date that approximates the predicted demand amount of one hour unit estimated in step S <b> 1 is searched, and the first and second factories 1 and 2 on the similar date are searched. With reference to the sending amount, a sending amount pattern (hereinafter referred to as an FC pattern) indicating a sending amount for 24 hours is created in units of one hour (step S2). It should be noted that the hourly sending amount of the first and second factories 1 and 2 indicated by the FC pattern is selected from the candidate values set as described above. That is, when each manufacturing site manufactures gas by the above-mentioned delivery amount pattern, it can be manufactured with an optimal manufacturing amount considering the manufacturing cost. The created FC pattern is input to a computer system provided in the central command room 7. Note that the predicted demand amount for 24 hours and the FC pattern for each factory are input to the computer system.
[0064]
Next, in the central command room 7, a pressure simulation is executed on the computer system to which the FC pattern is input in step S2 (step S3). By this pressure simulation, a pressure dynamic analysis of the high-pressure main line 10 is performed, and a pressure change graph on the day (24 hours) at each point of the high-pressure main line 10 is created. The computer system calculates the pressure change of the high-pressure trunk line 10 by giving the delivery amount from each manufacturing site and the flow load of the governors 3a to 3c connected to the high-pressure trunk line 10 every time. The flow loads of the governors 3a to 3c are apportioned from actual data such as past governor load actual values possessed by the computer system by giving the expected demand on the day and the governor set values scheduled for the day. Is set by
[0065]
Next, the central command room 7 verifies the pressure change graph created by executing the pressure simulation in step S3, and the gas pressure on the day changes between the minimum pressure and the maximum pressure of the high-pressure main line 10. Whether or not a predetermined target value is satisfied with respect to the daily change pattern of the high-voltage trunk line 10 set according to the season or the like (step S4). The daily change pattern is set in various ways depending on the season and the like, and will be described in detail later. If the pressure change graph satisfies all target values, the process proceeds to the next step S6. If the pressure change graph does not satisfy any target value, the process proceeds to the next step S5. To proceed.
[0066]
In step S5, the FC pattern is set so as to satisfy the target value confirmed in step S4 by changing the sending amount of each factory indicated by the FC pattern created in step S2 in one hour unit. Is corrected (step S5). Regarding the change in the delivery amount, the delivery amount in the hour unit of the first and second factories 1 and 2 after the change is selected from the candidate values set as described above. And it returns to said step S3, performs a pressure simulation again, and continues a process.
[0067]
In step S6, the FC pattern confirmed in step S4 is created as a gas delivery amount plan at each factory on that day (step S6), and the process according to the flowchart ends. Then, the central command room 7 transmits the determined FC pattern of each factory to the corresponding factory via a communication line.
[0068]
In addition, about the process of said step S4 and S5, you may be automatically performed by the computer system mentioned above. First, candidate values set in advance for each factory as described above are input to the computer system. Then, in the step S2, each hourly transmission amount for the FC pattern is input to the computer system, and further, the minimum pressure and the maximum pressure of the high-pressure main line 10 and a predetermined change for the daily change pattern to be described later. Input pressure target value. In step S3, the computer system executes a pressure simulation as described above. Next, in the step S4, the computer system determines whether or not the pressure simulation result obtained in the step S3 changes between the minimum pressure and the maximum pressure of the high-pressure main line 10 and the day. It is determined whether or not a predetermined target value for the change pattern is satisfied. When there is a time zone in which each pressure target value is not satisfied in the determination in step S4, the computer system reviews the delivery amount in a certain time zone preceding that time zone. Specifically, when the result of the pressure simulation is higher than the pressure target value, the computer system selects a new candidate value that is less than the currently set candidate value from a candidate value that is input in advance. Select and set to the above fixed time zone. On the other hand, when the pressure simulation result is lower than the pressure target value, the computer system selects a new candidate value having a one-stage delivery amount larger than the currently set candidate value from the candidate values input in advance, and Set to a certain time zone. Then, the processing is continued until the pressure simulation result satisfies the pressure target values by returning to step S3 and repeating the processing in the same manner as described above.
[0069]
Next, an example in which the above-described daily change pattern is set in winter will be described with reference to FIG. FIG. 4 (a) shows the predicted demand amount for 24 hours in the hour unit in winter, the delivery amounts X and Y of the first and second factories 1 and 2, and the total delivery amount of the delivery amounts X and Y. FIG. 4B is a pressure change graph of the high-pressure main line 10 for 24 hours in units of one hour showing the result of pressure simulation of these gas amounts.
[0070]
Since the winter is a period when there is a large amount of gas demand, an operation is performed to stably supply the maximum demand per hour. For example, in the winter season, as shown by the graph of the predicted demand amount in FIG. 4A, the demand amount becomes maximum from 18:00 to 23:00, and the demand amount at midnight decreases. Here, if there is no function of storing gas on the gas conduit formed between the consumers 21 to 23 from the first and second factories 1 and 2, the first and second factories 1 and 2 are used. Must have a delivery capacity corresponding to the maximum demand. However, as described above, in the gas supply system, as a function of storing gas, the main lines included in the holders 5a and 5b and the high-pressure main line 10 provided between the medium-pressure A gas conduit network 11 and the intermediate-pressure B gas conduit network 12 The line pack 14 is considered (see FIG. 1). That is, in the gas supply system, by using the function of storing these gases, the first and second gas can be stored by creating and storing the gas by the start of the time zone in which the maximum demand is expected. The gas delivery capacity of factories 1 and 2 can be supplemented. Hereinafter, an example in which the target value is set for the daily change pattern that supplements the gas delivery capability of the first and second factories 1 and 2 by using such a function of storing gas will be described.
[0071]
For example, the holders 5a and 5b store gas from the medium pressure A gas conduit network 11 in a time zone such as midnight when demand is small. And the holders 5a and 5b can supplement supply even if the delivery capacity of the factory is smaller than the actual demand amount by discharging the gas stored in the time zone with a large demand amount to the medium pressure B gas conduit network 12. . Further, for the main line pack 14 considered for the high-voltage main line 10, the high-voltage main line 10 is increased by increasing the amount of output from each factory by the start time of the time zone in which the maximum demand is assumed. The gas pressure stored in the main line pack 14 is reduced by lowering the gas pressure of the high-pressure main line 10 even if the delivery amount is smaller than the demand quantity during a time period when there is a large amount of demand. Supply to medium pressure A gas conduit network 11. Then, the gas pressure of the high-pressure main line 10 is increased by increasing the amount sent from each factory in the late-night time zone when the demand amount is small, and the gas is stored in the main line pack 14 of the high-pressure main line 10. That is, the main line pack 14 considered for the high-pressure main line 10 can be used to supplement the gas delivery capabilities of the first and second factories 1 and 2. In order to make this effect work most effectively, the start time of the time zone in which the maximum demand is assumed within the allowable operating pressure range of the high-pressure main line 10 (that is, the range of the minimum pressure to the maximum pressure). The target value is set near the maximum pressure, and the target value is set near the minimum pressure at the time when the time period ends. If priority is given to stable gas supply, such as when a demand that exceeds demand forecasts is required, the target value at the end of the time period in which the maximum demand is expected is used. Instead of setting the lower limit of the allowable pressure range, it may be set to a target value having a margin with respect to the lower limit (for example, a target value considering a certain margin pressure with respect to the lower limit).
[0072]
In the pressure change graph shown in FIG. 4B, a target value is set near the maximum pressure at 17:00 with respect to the gas pressure of the high-pressure main line 10, and a target value is set near the minimum pressure at 0 o'clock. This is a case where the delivery amounts X and Y of the first and second factories 1 and 2 are selected. As shown to Fig.4 (a), in the time slot | zone (18:00 to 23:00) which shows the maximum demand amount, the total sending amount X + Y of the 1st and 2nd factories 1 and 2 is in a state smaller than a demand amount. However, it can be seen that the gas pressure of the high-pressure main line 10 is within the operation allowable pressure range, and the gas supply can be supplemented even with the delivery capacity of the manufacturing plant smaller than the actual demand. In order to stably operate such a pressure change of the high-pressure main line 10, by performing a pressure simulation on the predicted demand in advance, the gas delivery amount of each factory is calculated in units of one hour. Create a delivery plan for each of the manufacturing sites. In the above description, target values are set near the maximum pressure and the minimum pressure, respectively. However, the target values near the maximum pressure are controlled by the gas pressure at the outlet of each factory, and are near the minimum pressure. It is preferable to manage the target value at the gas pressure at the point where the gas pressure is the lowest in the high-pressure main line 10 (the point farthest from each manufacturing site).
[0073]
In this way, when there is a time zone that shows the maximum demand amount exceeding the gas production capacity of each factory in winter, the demand amount for each hour is predicted in advance, and the function of storing gas such as the line pack effect is used. The maximum demand can be accommodated by preparing and storing gas in preparation for the time zone indicating the maximum demand. This can be dealt with without increasing the gas production capacity of each factory and without installing a new gas storage facility such as a holder, thereby preventing an increase in production cost due to new capital investment. In addition, since the manufacturing amount instructed to each manufacturing site is selected from candidate values in consideration of manufacturing costs, gas manufacturing at each manufacturing site can be performed with an optimal manufacturing amount with reduced manufacturing costs. Furthermore, as shown in FIG. 4, in the winter, the time zone indicating the maximum demand generally ends at midnight, and there is a time zone in which the demand is relatively high from early morning to near noon. In addition, in the time zone from midnight to early morning, the unit price of electric power supplied to each factory is set to be low (details will be described later). In other words, in the time zone from late night to early morning in winter, the amount of gas produced at a low power unit price is increased at each manufacturing site by building and storing gas using the function of storing gas such as the line pack effect. The manufacturing cost at each manufacturing site can be reduced.
[0074]
Next, an example in which the above-described daily change pattern is set in summer will be described with reference to FIG. FIG. 5 (a) shows the estimated demand amount for 24 hours in the summer unit, the delivery amounts X and Y of the first and second factories 1 and 2, and the total delivery amount of the delivery amounts X and Y. FIG. 5B is a pressure change graph of the high-pressure main line 10 for 24 hours in units of one hour, showing the result of pressure simulation of these gas amounts.
[0075]
Since summer is a period when the demand for gas is low, the sending capacity of each factory has a margin for the maximum demand for one hour. Therefore, at this time, an operation for reducing the unit price of electricity necessary for gas production is performed. For example, in the summer season, as shown in the graph of the predicted demand amount in FIG. 5B, the demand amount is almost constant from 10:00 to 21:00, and the demand amount at midnight is reduced. On the other hand, the unit price of power supplied to each factory is generally the highest from 10:00 to 17:00 (hereinafter referred to as heavy load time zone), and from 22:00 to 8:00 (hereinafter referred to as night time zone). Listed) is the cheapest. Therefore, in the summer production of gas at each manufacturing site, the production cost can be reduced by reducing the delivery amount in the heavy load time zone as much as possible and increasing the delivery amount in the night time zone as much as possible. In other words, the manufacturing cost can be reduced by using the above-described function for storing gas to store and store gas when the unit price of power is low. Hereinafter, an example in which the target value is set for the daily change pattern that reduces the manufacturing cost using the function of storing gas will be described.
[0076]
For example, the holders 5a and 5b store gas from the medium pressure A gas conduit network 11 at night time when the unit price of power is low. Then, the holders 5a and 5b pay out the gas stored in the heavy load time zone in which the unit price of power is high to the medium pressure B gas conduit network 12. As a result, the first and second factories 1 and 2 can send with a large amount of delivery X and Y during the nighttime period and with a small amount of delivery X and Y during the heavy load period. In addition, for the main line pack 14 considered for the high-pressure main line 10, the gas pressure of the high-pressure main line 10 is set to a high value by increasing the delivery amount from each factory during the night time period from the demand amount. The gas stored in the main line pack 14 is supplied to the medium pressure A gas conduit network 11 by reducing the above-mentioned delivery amount below the demand amount and reducing the gas pressure of the high pressure main line 10 during the load time period. Then, the amount of power sent from each factory is increased from 17:00 when the unit price of power is cheaper than the heavy load time zone, and the amount of output is increased more than the demand amount in the night time zone. Thus, the 1st and 2nd manufacturing plants 1 and 2 reduce each manufacturing cost by increasing each sending amount in the time slot | zone when an electric power unit price is cheap using the function to store gas. Can do. In order to make this effect work most effectively, the time when the night time zone in which the unit price of electric power is the lowest within the operation allowable pressure range of the high-pressure main line 10 (that is, the range of the minimum pressure to the maximum pressure) ends. The target value may be set near the maximum pressure, and the target value may be set near the minimum pressure at the start of the night time zone.
[0077]
In the pressure change graph shown in FIG. 5B, a target value is set near the maximum pressure at 8 o'clock with respect to the gas pressure of the high-pressure main line 10, and a target value is set near the minimum pressure at 22:00, This is a case where the delivery amounts X and Y of the first and second factories 1 and 2 are selected. As shown in FIG. 5A, in the night time zone (22:00 to 8:00), the total delivery amount X + Y of the first and second factories 1 and 2 is larger than the demand amount, but the high pressure The gas pressure of the main line 10 has moved to the vicinity of the upper limit of the allowable operating pressure range, and the first and second factories 1 and 2 have made gas reserves in the time zone in which the lowest unit price of power can be supplied. You can see that Further, in the heavy load time zone (10:00 to 17:00), the total delivery amount X + Y of the first and second factories 1 and 2 is less than the demand amount, but the gas pressure of the high-pressure main line 10 is It gradually shifts to near the lower limit of the allowable operating pressure range, and it can be seen that the first and second factories 1 and 2 reduce the gas production during the time zone when the highest unit price of electric power is supplied. . In order to stably operate such a pressure change of the high-pressure main line 10, by performing a pressure simulation on the predicted demand in advance, the gas delivery amount of each factory is calculated in units of one hour. Create a delivery plan for each of the manufacturing sites. In the above description, target values are set near the maximum pressure and the minimum pressure. However, the target values near the maximum pressure are controlled by the gas pressure at the outlet of each factory, and are near the minimum pressure. It is preferable to manage the target value at the gas pressure at the point where the gas pressure is the lowest in the high-pressure main line 10 (the point farthest from each manufacturing site).
[0078]
In this way, when the gas production capacity of each factory has room for the maximum demand in summer, etc., the demand for each hour is predicted in advance, and the function of storing gas such as the line pack effect is used. The gas production cost of each factory can be reduced by creating and accumulating gas during a time zone in which the unit price of power supplied to each factory is the lowest. In addition, since the manufacturing amount instructed to each manufacturing site is selected from candidate values in consideration of manufacturing costs, gas manufacturing at each manufacturing site can be performed with an optimal manufacturing amount with reduced manufacturing costs.
[0079]
Then, based on the FC pattern set as described above, the operation allowable pressure is used as the management value of the gas pressure of the high-pressure main line 10 on the day when the gas is manufactured by the first and second factories 1 and 2. Monitor to fill width. Further, the gas pressure in the high-pressure main line 10 may be monitored by setting a target value set according to the time zone in the vicinity of the upper and lower limits of the operation allowable pressure range described above as a management value. When the gas pressure deviates from these allowable operating pressure ranges or target values, the central command room 7 instructs the first and second factories 1 and 2 to change the manufacturing amount, and this manufacturing amount change instruction is also issued. It is selected from the above candidate values. As described above, in the first embodiment, the gas delivery amount at each manufacturing site is operated by the FC delivery method.
[0080]
In the description of the first embodiment described above, a pressure simulation in the high-pressure trunk line is performed in advance, and the gas delivery amount in each factory is set so as to satisfy the target value by predicting the gas pressure transition in the high-pressure trunk line in advance. ing. In this way, by predicting the gas pressure transition of the high-pressure main line in advance, changes in production volume due to the actual gas pressure value deviating from the allowable pressure range of the high-pressure main line when actually supplying gas can be prevented. can do. Further, since it is possible to detect that the actual value has deviated from the predicted gas pressure transition, it is possible to perform feedback control on the gas pressure transition predicted in advance.
[0081]
However, if these effects are not expected, the present invention may control the gas delivery amount of each factory so as to satisfy the set management value of the gas pressure without performing the pressure simulation. For example, the production amount of each factory is selected from the candidate values described above, and the management value of the gas pressure is set to the operation allowable pressure range of the high-pressure main line. In the actual gas supply, when the gas pressure in the high-pressure main line approaches the upper limit of the allowable operating pressure range, instructions are given to each manufacturing site with a candidate value with a small one-stage production amount. As the lower limit of the allowable operating pressure range is approached, each manufacturing site can manufacture with an optimum manufacturing amount with reduced manufacturing costs by instructing each manufacturing plant to manufacture with a candidate value with a large one-stage manufacturing amount. . In the actual gas supply, the target value set near the upper and lower limits of the operation allowable pressure range in the winter or summer described above as the control value of the gas pressure is set as the control value according to the time zone, and the candidate value The same effects as those in the winter or summer described above can be expected by giving the same manufacturing instruction to each factory with the manufacturing amount selected from the above.
[0082]
(Second Embodiment)
Next, a gas supply system according to a second embodiment of the present invention will be described. Before specifically describing the gas supply system according to the second embodiment, the concept in the embodiment will be described.
[0083]
As described in the first embodiment, in order to reduce the power consumption cost per unit gas amount at each manufacturing plant among the gas manufacturing costs, the first and second manufacturing plants 1 and 2 are used. There are a method of selecting a transmission amount from candidate values of the optimal transmission amount for each time and a method of using late-night power in a night time zone where the power unit price is inexpensive. In the first embodiment, in order to make these two methods compatible, the minimum pressure and the maximum pressure are within the allowable operating pressure range of the high-pressure main line 10 at the start 22:00 and the end 8:00 of the night time zone, respectively. On the condition that a target value is set in the vicinity and a transmission amount is selected from the candidate values, a transmission plan is made so as to satisfy each target value.
[0084]
Here, the gas pressure of the high-pressure main line 10 is decreased to the lowest pressure within the above-described allowable operating pressure range at the start of the night time zone, and the gas pressure of the high-pressure trunk line 10 is increased to the maximum pressure at the end of the night time zone of 8 hours. Then, the utilization rate of the midnight power can be maximized. However, when planning a delivery plan on the condition that the delivery amount is selected from the candidate values, it is possible to plan a delivery plan that moves around the minimum and maximum pressures, but the delivery amount that can be selected is limited. It is difficult to develop a delivery plan that accurately reaches the minimum and maximum pressures. And even if the condition for selecting the delivery amount from the candidate value is canceled (that is, selected from any delivery amount), the delivery plan for reaching the minimum and maximum pressures for maximizing the utilization rate of the midnight power May be more economical. Based on the above-described background, the gas supply system according to the second embodiment will be described as a method for further improving the economy relative to the first embodiment.
[0085]
The configuration of the gas supply system according to the second embodiment is the same as the block diagram schematically showing the gas supply system according to the first embodiment described with reference to FIG. Omitted. The candidate values at the first and second factories 1 and 2 are the same as those described in the first embodiment with reference to FIG.
[0086]
With reference to FIG. 6, the process for determination of the manufacturing amount performed in the central command room 7 which comprises the gas supply system which concerns on 2nd Embodiment is demonstrated. FIG. 6 is a flowchart for explaining the process for determining the production amount performed in the central command room 7.
[0087]
In FIG. 6, the central command room 7 predicts the gas demand amount on the day on which the production amount plan is made (step S <b> 11). Since the operation in step S11 is the same as that in step S1, detailed description thereof is omitted.
[0088]
Next, in the central command room 7, a past similar date that approximates the predicted demand amount of one hour unit estimated in step S11 is searched, and each of the first and second factories 1 and 2 on the similar date is searched. With reference to the sending amount, an FC pattern indicating the sending amount for 24 hours is created in units of one hour (step S12). The hourly sending amount of the first and second factories 1 and 2 selected in step S12 is selected from preset candidate values as in step S2, and the operation is the same as in step S2. Therefore, detailed description is omitted.
[0089]
Next, in the central command room 7, a pressure simulation is executed on the computer system to which the FC pattern is input in step S12 (step S13). Since the pressure simulation executed in step S13 is the same as that in step S3, detailed description thereof is omitted.
[0090]
Next, in the central command room 7, the pressure change graph created by executing the pressure simulation in step S <b> 13 is verified, and the gas pressure on that day is between the allowable operation pressure ranges set in the high-pressure main line 10. It is checked whether or not it has changed, and whether or not it has changed within the first target range set at the start and end times of the night time zone such as summer (step S14). If the pressure change graph satisfies all target values, the process proceeds to the next step S16. If the pressure change graph does not satisfy any target value, the process proceeds to the next step S15. To proceed.
[0091]
In the operation according to this flowchart, as described above, an operation for reducing the power consumption cost per unit gas production amount necessary for gas production is performed. For example, in the summer season, as described above, the demand amount is substantially constant from 10:00 to 21:00, and the demand amount at midnight is reduced (see FIG. 5B). On the other hand, the unit price of power supplied to each factory is generally highest from 10:00 to 17:00 (heavy load time zone) and lowest from 22:00 to 8:00 (night time zone). Therefore, in the summer production of gas at each manufacturing site, the production cost can be reduced by reducing the delivery amount in the heavy load time zone as much as possible and increasing the delivery amount in the night time zone as much as possible. In other words, the manufacturing cost can be reduced by using the above-described function for storing gas to store and store gas when the unit price of power is low.
[0092]
For example, with respect to the main line pack 14 considered for the high-pressure main line 10, the gas pressure of the high-pressure main line 10 is set to a high value by increasing the delivery amount from each factory during the nighttime period to be greater than the demand amount. The gas stored in the main line pack 14 is supplied to the medium pressure A gas conduit network 11 by reducing the above-mentioned delivery amount below the demand amount and reducing the gas pressure of the high pressure main line 10 during the load time period. And, in order to maximize the utilization rate of midnight power with the lowest electricity unit price set in the night time zone, at the end of the night time zone (8 o'clock) within the operation allowable pressure range of the high-voltage main line 10 The first target range is set near the maximum pressure and at the start (22:00) near the minimum pressure.
[0093]
For example, when the operation allowable pressure width of the high-pressure main line 10 is 2.5 to 4.0 MPa, the first target range is a pressure range of 2.5 to 3.0 MPa at the start of the night time period, It is set in the pressure range of 3.5 to 4.0 MPa at the end of the night time zone. In the actual gas supply operation, in order to reduce the probability of deviating from the operation allowable pressure range, an error with respect to the prior simulation or a fluctuation pressure range (for example, ± 0.1 MPa) may be considered. In this case, the first target range is 2.6 to 3.0 MPa at the start of the night time zone and 3.5 to 3.9 MPa at the end of the night time zone, taking the pressure range into consideration. Set.
[0094]
In step S15, by changing the hourly transmission amount of each factory indicated by the FC pattern created in step S12, each including the first target range confirmed in step S14. The FC pattern is corrected so as to satisfy the target value. Regarding the change of the delivery amount, the hourly delivery amounts of the first and second factories 1 and 2 after the change are selected from the candidate values set as described above, and are the same as in step S5. is there. And it returns to said step S13, performs a pressure simulation again, and continues a process.
[0095]
In step S16, the FC pattern confirmed in step S14 is created as a first delivery amount plan at each factory on that day. Then, the process proceeds to the next step.
[0096]
Next, in the central command room 7, with respect to the first delivery amount plan created in step S16, the delivery amount in a fixed time zone prior to the time zone managed in the first target range is determined from other than the candidate values. The selected FC pattern is input (step S17). For example, the first target range is set in the pressure range of 2.5 to 3.0 MPa and 3.5 to 4.0 MPa at the start (22:00) and end (8 o'clock) of the night time zone, respectively. Has been. In this case, the time zone for which the sending amount is changed in step S17 is, for example, 2 hours before the start time (22:00) and the end time (8 o'clock) of the night time zone. In other words, the time zone at 20 and 21:00 with respect to the start time of the night time zone, and the time zone at 6 and 7 o'clock with respect to the end time are time zones for which the transmission amount is selected from other than the candidate values.
[0097]
Here, with reference to FIG. 7, the transmission amount other than the candidate value selected in step S17 will be described. 7 is similar to FIG. 2 in the transmission amount per unit time (Nm ^Three / H) and unit price of power per unit delivery (yen / Nm ^Three ). Note that the graph shown in FIG. 7 does not consider the increase / decrease in the manufacturing cost due to the time period or day of the week when the power unit price is low.
[0098]
In FIG. 7, the power unit price Ee is set for the transmission amount FCe selected from the candidate values. As described above, the unit price of power at the first and second factories 1 and 2 has an inflection point that turns from decrease to increase, and can be manufactured at an advantageous unit price of power near the inflection point. The sending amount is set as a candidate value. That is, the power unit price Ee in the transmission amount FCe indicates a power unit price that is advantageous with respect to the power consumption cost. On the other hand, the power unit price En is set for a transmission amount FCn that is larger than the transmission amount FCe and selected from other than the candidate values. In this case, since the delivery amount is not advantageous for the power consumption cost, even if the delivery amount FCn is larger than the delivery amount FCe, the power unit price En higher than the power unit price Ee is indicated. Accordingly, in step S12 or S15, the FC pattern is created using such a transmission amount advantageous for the power consumption cost (for example, the transmission amount FCe is used. In step S17, the power consumption cost is reduced. Therefore, the FC pattern is created using all the transmission amounts including the disadvantageous transmission amount (for example, the transmission amount FCn).
[0099]
Returning to FIG. 6, the central command room 7 causes the computer system to which the FC pattern is input in step S <b> 17 to execute a pressure simulation (step S <b> 18). Since the pressure simulation executed in step S18 is the same as that in step S13, detailed description thereof is omitted.
[0100]
Next, the central command room 7 verifies the pressure change graph created by executing the pressure simulation in step S18, and the gas pressure on the day is between the operation allowable pressure ranges set in the high pressure main line 10. It is confirmed whether or not it has changed and whether or not the amount of transmission in the time zone managed in the first target range has reached the second target value (step S19). If the pressure change graph satisfies all target values, the process proceeds to the next step S21. If the pressure change graph does not satisfy some target values, the process proceeds to the next step S20. To proceed.
[0101]
Here, the second target value will be described. In order to maximize the utilization rate of midnight power with the lowest power unit price set in the night time zone, the second target value is set in the night time zone within the allowable operating pressure range of the high-voltage main line 10. The maximum pressure is set at the end (8 o'clock) and the minimum pressure at the start (22:00). For example, the allowable operating pressure range of the high-pressure main line 10 is 2.5 to 4.0 MPa, and the first target range is a pressure range of 2.5 to 3.0 MPa at the start of the night time zone, It is assumed that the pressure is set in a pressure range of 3.5 to 4.0 MPa at the end of the night time zone. In this case, the second target value is set with a gas pressure of 2.5 MPa at the start of the night time zone and a gas pressure of 4.0 MPa at the end of the night time zone. Note that the second target value may also take into account an error with respect to the prior simulation and a fluctuation pressure range (for example, ± 0.1 MPa), as in the first target range. In this case, the second target value is set at 2.6 MPa at the start of the night time zone and 3.9 MPa at the end of the night time zone in consideration of the pressure range.
[0102]
With reference to FIG. 8, the relationship between the pressure change graph by the pressure simulation described above, the first target range, and the second target value will be specifically described. FIG. 8 is a graph showing the relationship between the time zone until the end of the night time zone (8 o'clock) and the pressure (MPa).
[0103]
In FIG. 8, as described above, at the end of the night time zone (8 o'clock), the first target range is set near the maximum pressure of the operation allowable pressure range, and the second target value is set to the maximum pressure. Is set. And in the night time zone, since the gas pressure of the high-pressure main line 10 is increased by increasing the delivery amount from the first and second factories 1 and 2, the pressure change graph by the pressure simulation is It shows an upward trend toward 8 o'clock. The pressure change graph a is based on the first delivery amount plan created in step S16, and the delivery amount for each time period is selected from only the candidate value (for example, delivery amount FCe). . The pressure change graph a changes substantially in the center with respect to the first target range set at 8 o'clock, and satisfies the determination in step S14. On the other hand, in the pressure change graph b, the delivery amount at the time zones 6 and 7 (that is, the delivery amount from 6 o'clock to 8 o'clock) is larger than the setting of the pressure change graph a except for the candidate value (for example, delivery) The quantity FCn) is selected. The pressure change graph b has reached the second target value set at 8 o'clock and satisfies the determination in step S19. In this way, when an FC pattern is created by selecting the delivery amount including other than the above candidate values, a pressure simulation is performed using the FC pattern, thereby pinpointing the target value of the set gas pressure. Can be reached. In addition, since the second target value for maximizing the utilization rate of midnight power is set at the start and end time of the night time zone, an FC pattern that reaches the second target value is planned. Thus, an FC pattern that maximizes the utilization rate of midnight power can be created.
[0104]
In step S20, the second amount confirmed in step S19 is changed by changing the transmission amount in a certain time period prior to the time period in which the second target value is set in the FC pattern created in step S17. The FC pattern is corrected so as to reach the target value. And it returns to said step S18, performs a pressure simulation again, and continues a process.
[0105]
The change in the sending amount in step S20 is typically selected and changed from the sending amount other than the candidate value for the certain time period, but by changing the sending amount for one time period, The transmission amount may be selected from the candidate values in the other time zone, or may be changed to another candidate value for a time zone other than the fixed time zone. As described above, the second target value is set to the highest pressure at the end of the night time zone (8:00) and the lowest pressure at the start (22:00). In the above steps S17 and S20, in order to select a delivery amount that reaches these second target values, the delivery amount is increased with respect to a certain time zone preceding 8 o'clock, and for a certain time zone preceding 22:00. The amount of delivery will be reduced. For example, when the gas pressure is increased by increasing the delivery amount with respect to the certain time period preceding the above 8 o'clock, the gas pressure in other time periods also increases. As a result, a new candidate value having a one-stage transmission amount smaller than the currently set transmission amount is selected for a certain time zone preceding 22:00, or the transmission amount in the time zone not to be changed is set to one in step S17. It is possible to select a new candidate value with a small step transmission amount.
[0106]
In step S21, the FC pattern confirmed in step S19 is created as a second delivery amount plan in each factory on that day. Then, the process proceeds to the next step.
[0107]
Next, in the central command room 7, the first and second delivery amount plans created in steps S16 and S19 are compared to select the more economical one (step S22), and the processing according to the flowchart ends. To do. The central command room 7 transmits the FC pattern of each factory based on the determined first or second delivery amount plan to the corresponding factory via the communication line.
[0108]
A method for comparing the first and second delivery amount plans performed in step S22 will be described. The central command room 7 verifies whether the power consumption cost by the second delivery amount plan created in step S21 is reduced with respect to the first delivery amount plan created in step S16. That is, select a transmission amount other than the candidate value for the FC pattern created by the transmission amount that selects only the candidate value and a certain time zone preceding the time zone in which the second target value is set, Compare the power consumption cost with the FC pattern that maximizes the utilization rate of midnight power, and select a highly economical FC pattern.
[0109]
In order to make the description more specific, the concept of economic comparison will be described using the power unit prices Ee and En for the delivery amounts FCe and FCn described in FIG. 7 and the pressure change graphs a and b described in FIG. .
[0110]
The unit prices in the daytime and nighttime periods corresponding to the power unit price Ee are set as power unit prices Eed and Een, respectively. The unit prices in the daytime and nighttime periods corresponding to the power unit price En are set as power unit prices End and Enn, respectively. In general, Eed> Een and End> Enn. Then, t is a time during which a transmission amount is selected from other than the above candidate values in a certain time period preceding 8:00. The pressure change graph a in FIG. 8 is manufactured with the delivery amount FCe for all the time zones up to 8 o'clock, and the pressure change graph b shows the delivery amount only at the 6 o'clock and 7 o'clock time zones (t = 2). Suppose that it is manufactured by FCn.
[0111]
At this time, the increase in power consumption cost by the pressure change graph b with respect to the pressure change graph a is
(Enn × FCn−Een × FCe) × t (1)
And the increased delivery by the pressure change graph b is
(FCn-FCe) × t
It is. On the other hand, consider the power consumption cost for manufacturing the increased delivery amount in the daytime. When it is assumed that the increased transmission amount is included in the transmission amount FCe, the power consumption cost is
(FCn−FCe) × t × Eed (2)
It becomes. And the result of said Formula (1) and (2) is compared, and when the result of the said Formula (2) is large, it is judged that the economical efficiency of the pressure change graph b is high. Here, in the nighttime period, the time t for which the transmission amount is selected from the candidate values other than the candidate value can be arbitrarily set theoretically. However, when considering the reduction of the power consumption cost, a short time ( For example, it is preferable to set t ≦ 2).
[0112]
As described above, the concept of comparing the power consumption costs in the case where all planned transmission amounts are selected from the above candidate values and in the case where the utilization rate of midnight power is maximized has been described. However, when comparing the first and second delivery amount plans, there may be a large number of time zones in which each delivery amount is different as described in the operation of step S20, and the power consumption cost in each time zone. The increase or decrease in the relationship is complicated. Therefore, in the economic comparison in step S22, the power consumption cost required by the first and second delivery amount plans is calculated using the power unit price corresponding to the time zone and the delivery amount, and the total consumption for 24 hours. Calculate and compare power costs.
[0113]
Then, based on the FC pattern selected in step S22, the operation allowable pressure is used as the management value of the gas pressure of the high-pressure main line 10 on the day when the gas is manufactured by the first and second factories 1 and 2. Monitor to fill width. Furthermore, the gas pressure of the high-pressure main line 10 may be monitored by setting the second target value set according to the time zone to the maximum and minimum pressures of the operation allowable pressure range described above as a management value. When the gas pressure of the high-pressure main line 10 deviates from the planned value due to the difference between the predicted gas consumption and the actual results, for example, two hours before the time zone in which the second target value is set, the above-mentioned again. Run a pressure simulation. This pressure simulation is similarly executed based on the gas pressure of the high-pressure main line 10 at that time and the subsequent demand amount prediction, and the result is transferred from the central command room 7 to the first and second factories 1 and 2. Instruct. Thus, also in the second embodiment, the gas delivery amount at each manufacturing site is operated by the FC delivery method.
[0114]
Note that the processing in steps S14 to S16 and S19 to S22 may be automatically performed by the above-described computer system. First, candidate values set in advance for each factory as described above are input to the computer system. In steps S12 and S17, the hourly output amounts for the FC pattern are input to the computer system. Further, the minimum pressure and the maximum pressure of the high-pressure main line 10, and the first target range. And the second target value.
[0115]
In steps S13 and S18, the computer system executes a pressure simulation as described above. Next, in steps S14 and S19, in the computer system, the pressure simulation result obtained in steps S13 and S18 changes between the minimum pressure and the maximum pressure of the high-pressure main line 10, and It is determined whether or not the first target range and the second target value are satisfied. If there is a time zone that does not satisfy the respective targets in the determinations at steps S14 and S19, the computer system reviews the transmission amount in a certain time zone preceding that time zone at steps S15 and S20.
[0116]
Specifically, in step S15, when the result of the pressure simulation is higher than the pressure target value such as the first target range, the computer system has a new one-step delivery amount smaller than the currently set candidate value. A candidate value is selected from candidate values that have been input in advance, and set in the predetermined time period. On the other hand, when the pressure simulation result is lower than the pressure target value such as the first target range, the computer system is pre-inputted with a new candidate value having a one-step delivery amount larger than the currently set candidate value. The candidate value is selected and set in the above-mentioned fixed time zone. Then, in the same manner as described above, the process returns to step S13 to repeat the process, thereby continuing the process until the pressure simulation result satisfies the pressure target values.
[0117]
In step S20, if the result of the pressure simulation is higher than the pressure target value such as the second target value, the computer system sends an arbitrary delivery amount less than the currently set delivery amount or one-step delivery. A new candidate value with a small amount is selected from candidate values that have been input in advance, and set in the predetermined time period. On the other hand, when the result of the pressure simulation is lower than the pressure target value such as the second target value, the computer system has a new arbitrary delivery amount smaller than the currently set delivery amount or a new one-stage delivery amount. A candidate value is selected from candidate values input in advance, and set in the predetermined time period. Then, in the same manner as described above, the process returns to step S18 and repeats the process, so that the process is continued until the pressure simulation result satisfies the pressure target values.
[0118]
In step S22, the computer system calculates a power consumption cost for the first and second transmission amount plans created in steps S16 and S21, and outputs each power consumption cost.
[0119]
As described above, according to the gas supply system according to the second embodiment, it is possible to devise a gas delivery amount plan that makes the best use of the cheapest midnight power set in the night time zone. Further, as the gas delivery amount plan used in the gas supply system, a highly economical one is selected from the gas delivery amount plan described in the first embodiment and the gas delivery amount plan that makes the best use of midnight power. Therefore, it is possible to further reduce the power consumption cost with respect to the first embodiment.
[0120]
As described above, according to the first and second embodiments, the demand predicted for all consumers on the system using the function of storing gas such as the line pack effect in the gas supply system. By setting the gas delivery rate so as to appropriately correspond to the volume and reduce the manufacturing cost, the gas manufacturing capacity of each manufacturing plant can be supplemented or the gas manufacturing cost of each manufacturing plant can be reduced. It can be carried out.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing a gas supply system according to first and second embodiments of the present invention.
FIG. 2 is a graph illustrating an example of a unit price unit price of electric power obtained by calculation.
FIG. 3 is a view for explaining a process for determining a manufacturing amount to be manufactured at the first and second manufacturing plants 1 and 2 performed in the central command room 7 of FIG. 1 according to the first embodiment of the present invention; It is a flowchart.
FIG. 4 shows a predicted demand amount for 24 hours in units of one hour in winter in the first embodiment, delivery amounts X and Y of the first and second factories 1 and 2, and delivery amounts X and Y. It is the graph which shows total delivery amount X + Y, and the pressure change graph of the high-pressure trunk line 10 for 24 hours in the unit of 1 hour which shows the result of having performed pressure simulation of those gas amounts.
FIG. 5 shows a predicted demand amount for 24 hours in an hour unit in the summer of the first embodiment, delivery amounts X and Y of the first and second factories 1 and 2, and delivery amounts X and Y. It is the graph which shows total delivery amount X + Y, and the pressure change graph of the high-pressure trunk line 10 for 24 hours in the unit of 1 hour which shows the result of having performed pressure simulation of those gas amounts.
6 is a diagram for explaining a process for determining a manufacturing amount to be manufactured at the first and second manufacturing plants 1 and 2 performed in the central command room 7 of FIG. 1 according to the second embodiment of the present invention. It is a flowchart.
FIG. 7 is a graph showing a relationship between a transmission amount per unit time and a power unit price per unit transmission amount.
FIG. 8 is a graph showing the relationship between time zone and pressure until the end of the night time zone.
FIG. 9 is a block diagram schematically showing a conventional gas supply system from each manufacturing site to a consumer.
[Explanation of symbols]
1 ... 1st factory
2 ... Second factory
3, 4, 6 ... governor
5 ... Holder
7 ... Central command room
10 ... High-pressure trunk line
11 ... Medium pressure A gas pipeline network
12 ... Medium pressure B gas pipeline network
13 ... Low pressure gas supply conduit network
14 ... Main line pack
21-23 ... consumers

Claims (17)

A gas supply method in which a factory supplies gas to a consumer via a supply line,
A supply line pressure management step for setting a time at which the gas pressure in the supply line should become maximum and a maximum pressure target value at that time so that the gas storage amount in the supply line becomes maximum at a predetermined time;
The gas pressure of the supply line in all time zones that reach the maximum pressure target value at the time set in the supply line pressure management step and are divided every predetermined time unit And a production amount setting step of setting a production amount of gas for each time unit at the manufacturing site so as to change within a pressure range allowed for the supply line. Furthermore, a demand amount prediction step for obtaining a demand demand for each time unit by predicting the gas demand amount of the consumer in advance for each predetermined time unit,
The supply line pressure management step is based on the predicted demand amount so that the gas storage amount in the supply line is maximized in a time zone in which the predicted demand amount obtained in the demand amount prediction step is relatively small. The gas supply method according to claim 1, wherein a time at which the gas pressure in the supply line should be maximized and the maximum pressure target value are set.   Furthermore, the gas supply method of Claim 1 or 2 including the gas supply operation | use step which operates gas supply in the said factory using the said gas production amount set at the said production amount setting step. Further, a pressure simulation for predicting the gas pressure in the supply line in advance for each time unit based on the predicted demand amount obtained in the demand amount prediction step and the gas production amount set in the production amount setting step. Steps,
The gas pressure predicted in the pressure simulation step is such that the gas pressure in the supply line in all time zones changes within the allowed pressure range, and the maximum pressure target set in the supply line pressure management step. A pressure check step for checking in advance whether the value is satisfied,
4. The gas supply operation step according to claim 3, wherein the gas supply operation step uses the gas production amount that is set in the production amount setting step and is confirmed in advance in the pressure confirmation step. 5. Gas supply method.   The maximum pressure target value set in the supply line pressure management step is within the allowed pressure range at the start of a time zone in which the predicted demand amount obtained in the demand amount prediction step is relatively large. The gas supply method according to claim 2, wherein the upper limit is set. The supply line pressure management step further includes a lower limit within the allowable pressure range in the supply line at a time when a time zone in which the predicted demand obtained in the demand prediction step is relatively large ends. Set the minimum pressure target value,
The production amount setting step further changes the minimum pressure target value at a time when a time period in which the predicted demand amount set in the supply line pressure management step relatively increases the gas pressure of the supply line ends. The gas supply method according to claim 5, wherein a gas production amount for each time unit at the manufacturing site is set.   The maximum pressure target value set in the supply line pressure management step is within the allowable pressure range in the supply line at a time when a time zone in which the unit price of power supplied to the factory is relatively low ends. The gas supply method according to claim 2, wherein the upper limit is set. The supply line pressure management step further includes a minimum pressure target value at a lower limit within the allowable pressure range in the supply line at a time when a time zone in which a unit price of power supplied to the factory is relatively low is started. Set
The production amount setting step further changes the minimum pressure target value at a time when the gas pressure of the supply line starts at a time when the unit price of the power set in the supply line pressure management step is relatively low. The gas supply method according to claim 7, wherein a gas production amount for each time unit at the manufacturing site is set.   5. The gas according to claim 1, wherein a maximum pressure target value at a time when the gas pressure of the supply line set in the supply line pressure management step should be maximized is set according to a season. Supply method.   The demand amount prediction step considers a plurality of parameters for the day for which the predicted demand amount is obtained, and obtains the predicted demand amount by using gas demand amount data on a past day similar to the parameter. The gas supply method according to any one of claims 2 to 4. Furthermore, a data collection step for collecting data for calculating the production cost of the gas at the factory,
A candidate value group determining step for determining a candidate value group of production quantities at the manufacturing site based on the data collected in the data collecting step so that the manufacturing cost is relatively low,
5. The gas supply method according to claim 1, wherein the production amount setting step sets a gas production amount for each time unit at the manufacturing site from the candidate value group determined in the candidate value group determination step.   The gas according to claim 11, wherein the candidate value group determined in the candidate value group determination step includes a production amount value corresponding to an inflection point at which the production cost turns from a decrease to an increase. Supply method. Furthermore, a data collection step for collecting data for calculating the production cost of the gas at the factory,
A candidate value group determining step for determining a candidate value group of production quantities at the manufacturing site based on the data collected in the data collecting step so that the manufacturing cost is relatively low,
The supply line pressure management step sets the maximum pressure target value to an upper limit within the allowable pressure range in the supply line, and has a predetermined range;
The production amount setting step includes:
A first gas production amount in which the gas production amount per unit of time at the factory is selected from the candidate value group so that the gas pressure of the supply line changes the maximum pressure target value;
The amount of gas produced per unit of time at the production site is set to the second gas production so that the upper limit within the allowable pressure range in the supply line is reached at the time when the gas pressure of the supply line should be maximum. The gas supply method according to claim 1, wherein the gas supply method is set as an amount. A gas production amount selection step of calculating a production cost of each gas in the first and second gas production amounts set in the production amount setting step, and selecting a gas production amount having a low production cost;
The gas supply method according to claim 13, wherein the gas supply operation step uses the gas production amount selected in the gas production amount selection step to operate the gas supply in the factory.   In the production amount setting step, the second gas production amount is selected from a group other than the candidate value group with respect to the time zone before a certain time prior to the time when the gas pressure of the supply line should be maximized. The gas supply method according to claim 13, wherein the candidate value group is selected for the time zone.   The gas according to claim 13, wherein the supply line pressure management step sets a time at which the gas pressure should be maximized to a time at which a time zone in which a unit price of power supplied to the factory is relatively low ends. Supply method. The supply line pressure management step further includes a lower limit within the allowable pressure range in the supply line at a start time of a time zone in which a unit price of power supplied to the factory is relatively low, and a predetermined value. Set the minimum pressure target value with a range,
The production amount setting step further includes:
Setting the first gas production volume so that the gas pressure in the supply line changes the minimum pressure target value;
The second gas production amount is set so that the gas pressure in the supply line reaches a lower limit within the allowable pressure range in the supply line at a time when a time period when the unit price of the power is relatively low starts. The gas supply method according to claim 13, wherein the gas supply method is set.

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