Transportation flow optimization calculation method suitable for tandem sewage lifting pump station group with gravity flow pipeline convergence in middle

Abstract

The invention discloses a conveying flow optimization calculation method suitable for a tandem sewage lifting pump station group with gravity flow pipeline convergence in the middle. In an urban sewage collecting area, compared with a sewage treatment plant, the terrain is lower, and when sewage cannot flow automatically through gravity during conveying, a sewage pump station is usually adopted in a pressure flow mode. The design flow of a 1 # pump station is calculated; calculating single-time operation time of the 1 # pump station when the 1 # pump station is most unfavorable; temporarily determining the designed output flow of the 2 # pump station; the designed flow of the 2 # pump station is equal to the designed flow of the 1 # pump station; calculating the regulation and storage volume of a middle afflux gravity flow pipeline; calculating the available regulation and storage volume of the 2 # pump station under the most unfavorable condition; calculating the single operation time of the 2 # pump station; and checking whether the 2 # pump station meets the pump station design specification requirements or not. By adjusting the available regulation and storage volume of the pump station and optimizing the design flow of the pump station, the design scale of the pump station is reduced to a certain extent, the construction investment can be effectively reduced, and the operation cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of municipal sewage pipe networks, and in particular relates to a method for optimizing the calculation of the delivery flow rate of a series-type sewage lifting pump station group into which a gravity flow pipe converges. Background Art

[0002] When the urban sewage receiving area is lower than the sewage treatment plant and the sewage cannot be transported by gravity, the sewage pump station is usually used to transport the sewage to the sewage treatment plant in the form of pressure flow. If other sewage needs to be collected between the sewage lifting pump station and the sewage treatment plant, it is necessary to add a sewage lifting pump station between the two points, and use the form of two pump stations in series to transport the total amount of sewage after the intermediate gravity pipeline is collected to the sewage treatment plant. Usually, the design flow of the rear-end lifting pump station should be the sum of the design flow of the starting sewage lifting pump station and the intermediate collection flow. The design flow of the rear-end lifting pump station usually needs to be greater than the design flow of the starting pump station. Summary of the invention

[0003] In order to make up for the shortcomings of the prior art, the present invention provides a method for optimizing the delivery flow rate of a series-type sewage lift pump station group with a gravity flow pipeline in the middle, which can effectively reduce the design flow rate of the rear-end lift pump station, save construction investment, and reduce operating costs.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for optimizing the flow rate of a series-type sewage lifting pump station group with a gravity flow pipeline in the middle, characterized in that it includes the following steps:

[0006] Step 1: Calculate the design flow of pump station 1#;

[0007] Step 2: Calculate the single operation time of the 1# pump station when it is most unfavorable;

[0008] Step 3: tentatively determine the design outflow of pump station 2#;

[0009] Assumption: The design outflow of 2# pump station = the design outflow of 1# pump station;

[0010] Step 4: Calculate the storage capacity of the intermediate gravity flow pipeline;

[0011] Step 5: Calculate the available storage capacity of the 2# pump station under the most unfavorable conditions;

[0012] Step 6: Calculate the single operation time of 2# pump station;

[0013] Step 7: Check whether the 2# pump station meets the pump station design specification requirements;

[0014] Step 8: If the calculation results meet the requirements, the design parameters can be used for pump station design; if the calculation results do not meet the requirements, it is necessary to adjust the adjustable storage capacity of the 2# pump station and recalculate until the requirements are met.

[0015] Furthermore, in step 1, the sewage volume is calculated based on the catchment area of ​​the 1# pump station, and the design parameters of the 1# pump station are determined, which needs to satisfy the design flow of the 1# pump station > the sewage volume in the area.

[0016] Furthermore, in step 2, the single operation time of the 1# pump station at the most unfavorable time is specifically:

[0017] Operation time = effective volume of 1# pump station / (designed outflow of 1# pump station - designed inflow of 1#).

[0018] Furthermore, in step 5, when the most unfavorable operating condition of the 2# pump station is that the liquid level of the 2# pump station is at the critical point where the pump is not yet turned on, the volume of the intermediate sewage that can be used to regulate the 2# pump station is the volume between the bottom of the water pump inlet pipe and the highest pump start level + the available regulating volume of the intermediate gravity flow pipeline. The available regulating volume must meet the following requirements:

[0019] Available regulating and storing capacity>1# pump station single operation time × intermediate gravity flow pipeline inflow flow.

[0020] Further, in step 6, when the water pump of the 2# pump station is turned on, the water inlet flow of the 2# pump station = the design flow of the 1# pump station + the intermediate sewage flow, and the water outlet of the 2# pump station = the design flow of the 1# pump station;

[0021] The single operation time of 2# pumping station = the single operation time of 1# pumping station + the amount of sewage entering the intermediate area / the design flow of the pumping station.

[0022] Furthermore, pipeline storage time = pipeline storage volume / pipeline design flow.

[0023] Furthermore, in step 7, when the total regulation time of the 2# pumping station is greater than the single operation time of the 2# pumping station and the start and stop times of the 2# pumping station do not exceed 6 times, it is verified that the start and stop times of the water pump per hour do not exceed 6 times.

[0024] Beneficial effects of the present invention:

[0025] The present invention is applicable to the situation where there is an intermediate gravity flow pipe in the design of the municipal sewage pipe network: when sewage needs to be transported through multiple lifting pump stations, it is particularly suitable for the design where there is an intermediate gravity flow pipe in the design; by adjusting the available storage volume of the pump station, optimizing the design flow of the pump station, and reducing the design scale of the pump station to a certain extent, it can effectively reduce construction investment and save operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an operation flow chart of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific implementation modes.

[0028] There are two sewage lifting pump stations connected in series, namely 1# and 2# lifting pump stations. The design flow of 1# lifting pump station is the sewage volume in its service area. There is a small amount of gravity flow sewage flowing between 1# pump station and 2# pump station. According to the conventional design concept, the design flow of 2# pump station is:

[0029] Design flow of 2# pump station = design flow of 1# pump station + intermediate inflow flow

[0030] With this design, the design flow of 2# pump station is greater than the design flow of 1# pump station.

[0031] In order to save construction investment and reduce operating costs, the present invention proposes a flow rate optimization design method for a series-type sewage lift pump station with an intermediate gravity flow pipeline, which can effectively reduce the design flow rate of the rear-end lift pump station. Figure 1 As shown, the present invention comprises the following steps:

[0032] Step 1: Calculate the design flow of pump station 1#;

[0033] According to the catchment area of ​​1# pump station, calculate the sewage volume and determine the design parameters (flow rate, head) of 1# pump station. The design flow rate of 1# pump station should be greater than the sewage volume in the area.

[0034] Step 2: Calculate the single operation time of the 1# pump station at the most unfavorable time. The specific single operation time of the 1# pump station at the most unfavorable time is:

[0035] Operation time = effective volume of 1# pump station / (designed outflow of 1# pump station - designed inflow of 1#);

[0036] Step 3: tentatively determine the design outflow of pump station 2#;

[0037] Assumption: The design outflow of 2# pump station = the design outflow of 1# pump station;

[0038] Step 4: Calculate the storage capacity of the intermediate gravity flow pipeline;

[0039] Calculate the available storage capacity of the gravity flow pipeline according to the actual situation. Here, take the DN800 gravity flow pipeline as an example: the gravity flow pipeline is designed to be 0.75 full, so there is about 20% of the space in the pipeline that can be used to store sewage. Long-distance transmission pipelines themselves have a certain regulating volume;

[0040] Pipeline storage time = pipeline storage volume / pipeline design flow.

[0041] Step 5: Calculate the available storage capacity of the 2# pump station under the most unfavorable conditions; the most unfavorable operating condition of the 2# pump station is when the liquid level of the 2# pump station is at the critical point where the pump is not yet turned on, and the volume of the intermediate sewage that can be used to store the 2# pump station is the volume between the bottom of the water pump inlet pipe and the highest pump start level + the available storage capacity of the intermediate gravity flow pipeline. The available storage capacity must meet the following requirements:

[0042] Available regulating and storing capacity>1# pump station single operation time × intermediate gravity flow pipeline inflow flow.

[0043] Step 6: Calculate the single operation time of 2# pump station;

[0044] When the water pump of 2# pump station is turned on, the water inlet flow of 2# pump station = the design flow of 1# pump station + the intermediate sewage flow, and the water outlet of 2# pump station = the design flow of 1# pump station;

[0045] Single operation time of 2# pump station = single operation time of 1# pump station + intermediate sewage volume / design flow of pump station;

[0046] Step 7: Check whether the 2# pump station meets the pump station design specification requirements;

[0047] When the total storage time of 2# pump station is greater than the single operation time of 2# pump station and the start and stop times of 2# pump station do not exceed 6 times, the start and stop times of the check pump per hour shall not exceed 6 times;

[0048] Step 8: If the calculation results meet the requirements, the design parameters can be used for pump station design; if the calculation results do not meet the requirements, it is necessary to adjust the adjustable storage capacity of the 2# pump station and recalculate until the requirements are met.

[0049] Implementation Cases:

[0050] This embodiment takes the sewage pipeline and sewage lifting pump station of a city in Yunnan as an example to explain in detail the specific application of a method for optimizing the flow rate of a series sewage lifting pump station group with a gravity flow pipeline in the middle:

[0051] Step 1: Determine the design flow and regulating volume of pump station 1#

[0052] Design flow: Determine the design outflow flow of 1# pump station based on the inflow flow of 1# pump station. The design outflow flow is greater than the inflow flow.

[0053] Adjustment volume: Calculate the effective adjustment volume of 1# pumping station based on the pump start-up liquid level and pump stop water level of 1# pumping station.

[0054] Step 2: Calculate the operating time of pump station 1 under the most unfavorable conditions

[0055] Run time calculation:

[0056]

[0057] Step 3: Temporarily determine the design flow rate of pump station 2#

[0058] Assume that the design flow rate of 2# pump station is the same as that of 1# pump station.

[0059] Step 4: Calculate the storage capacity of the intermediate gravity flow pipe

[0060] Gravity flow pipe design: According to the actual situation, the intermediate sewage pipe is designed as a non-full flow gravity pipe.

[0061] Calculation of pipeline storage capacity:

[0062] Pipeline storage capacity V = pipeline free area × pipe length

[0063] Step 5: Calculate the available storage capacity of 2# pump station under the most unfavorable conditions

[0064] The most unfavorable operating condition of the 2# pump station, that is, when the liquid level of the 2# pump station is at the critical point of the highest pump start level but the pump has not yet started, the volume of the intermediate sewage that can be used to regulate the 2# pump station is the volume between the bottom of the water pump inlet pipe and the highest pump start level + the available regulation volume of the intermediate gravity flow pipeline. The regulation volume needs to meet the following requirements:

[0065] Available storage capacity>1# pump station single operation time × intermediate gravity flow pipeline inflow flow

[0066] Step 6: Calculate the single operation time of pump station 2#

[0067] Single operation time of 2# pump station = Single operation time of 1# pump station + Intermediate sewage volume / Design flow of pump station

[0068] Step 7: Check the start and stop times of pump station 2#

[0069] The start and stop times of the 2# pump station comply with the regulation of not exceeding 6 times per hour.

[0070] Therefore, the same design flow rate is selected for the 2# pump station and the 1# pump station, which can not only meet the requirements of the operating conditions, but also achieve the purpose of reducing the installed power of the 2# pump station and the subsequent operating costs.

[0071] The content of the present invention is not limited to the embodiments listed, and any equivalent changes made to the technical solution of the present invention by ordinary technicians in this field after reading the description of the present invention are covered by the claims of the present invention.

Claims

1. A method for optimizing the flow rate of a series of sewage lifting pump stations with a gravity flow pipeline in the middle, characterized in that: The steps include: Step 1: Calculate the design flow of pump station 1#; Step 2: Calculate the single operation time of the 1# pump station when it is most unfavorable; Step 3: tentatively determine the design outflow of pump station 2#; Assumption: The design outflow of 2# pump station = the design outflow of 1# pump station; Step 4: Calculate the storage capacity of the intermediate gravity flow pipeline; Step 5: Calculate the available storage capacity of the 2# pump station under the most unfavorable conditions; Step 6: Calculate the single operation time of 2# pump station; Step 7: Check whether the 2# pump station meets the requirements of the pump station design specifications; Step 8: If the calculation results meet the requirements, the design parameters can be used for pump station design; if the calculation results do not meet the requirements, it is necessary to adjust the adjustable storage capacity of the 2# pump station and recalculate until the requirements are met.

2. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 1 is characterized in that: In step 1, the sewage volume is calculated based on the catchment area of ​​1# pump station, and the design parameters of 1# pump station are determined, which needs to satisfy the requirement that the design flow of 1# pump station > the sewage volume in the area.

3. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 2 is characterized in that: In step 2, the single operation time of the 1# pump station at the most unfavorable condition is: Operation time = effective volume of 1# pump station / (designed outflow of 1# pump station - designed inflow of 1#).

4. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 3 is characterized in that: In step 5, when the most unfavorable operating condition of the 2# pump station is that the liquid level of the 2# pump station is at the critical point where the pump is not yet turned on, the volume of the intermediate sewage that can be used to regulate the 2# pump station is the volume between the bottom of the water pump inlet pipe and the highest pump start level + the available regulating volume of the intermediate gravity flow pipeline. The available regulating volume must meet the following requirements: Available regulating and storing capacity>1# pump station single operation time × intermediate gravity flow pipeline inflow flow.

5. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 4 is characterized in that: In step 6, when the water pump of pump station 2 is turned on, the water inlet flow of pump station 2 = the design flow of pump station 1 + the intermediate sewage flow, and the water outlet of pump station 2 = the design flow of pump station 1; The single operation time of 2# pump station = the single operation time of 1# pump station + the amount of sewage flowing into the intermediate station / the design flow of the pump station.

6. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 5 is characterized in that: Pipeline storage time = pipeline storage volume / pipeline design flow.

7. The method for optimizing the flow rate of a series-connected sewage lifting pump station group with a gravity flow pipeline in the middle according to claim 6 is characterized in that: In step 7, when the total regulation time of the 2# pump station is greater than the single operation time of the 2# pump station and the start and stop times of the 2# pump station do not exceed 6 times, check that the start and stop times of the water pump do not exceed 6 times per hour.

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