Multi-type heat supply unit group cooperative control device

Abstract

The application provides a multi-type heat supply unit group collaborative control device, which comprises a first unit and a second unit; the first unit is a high-back-pressure modified unit, and original circulating water is replaced by heat network return water; the second unit is an extraction condensing unit. A heat supply pipeline modification system is designed and developed to enable the high-back-pressure unit to simultaneously meet the needs of heat and electricity load and to have a flexible adjustment system for heat supply, power generation and peak shaving.

Description

Technical Field

[0001] This invention relates to the field of thermal power plant technology, and in particular to a collaborative control device for a group of multiple types of heating units. Background Technology

[0002] To meet the heating demand in northern China, many existing thermal power generating units have implemented "low-pressure cylinder dual back pressure dual rotor interchange" circulating water heating retrofits to achieve high back pressure circulating water heating.

[0003] During the heating season, the low-pressure cylinder uses a high back pressure rotor, and the purpose of modifying it is to use the exhaust steam from the low-pressure cylinder to heat the circulating water of the heating network.

[0004] By using the circulating water of the heating network to replace the original circulating water of the pure condensing unit, the waste heat of the turbine exhaust steam is recovered to heat the return water of the heating network in the first stage. At the same time, the heating steam extracted from other units can be used to heat the heating network heater in the second stage, which greatly improves the heating capacity of the unit and reduces the cold source loss of the high back pressure turbine exhaust steam to zero, thereby achieving the goal of energy saving and reducing coal consumption. Summary of the Invention

[0005] To address the technical problems mentioned in the background art, the present invention aims to provide a multi-type heating unit group collaborative control device.

[0006] To address the technical problems mentioned in the background section, the present invention proposes the following technical solution:

[0007] A multi-type heating unit group coordinated control device, comprising Unit 1 and Unit 2;

[0008] Unit 1 is a high back pressure retrofit unit, with the original circulating water replaced by the return water from the heating network. Unit 2 is a condensing extraction unit.

[0009] After the return water of the heating network is heated in the first stage by the condenser of the high back pressure unit of Unit 1, it is then heated in the second stage by the heating network heater through the respective heating extraction steam pipelines of Unit 1 and Unit 2. The flow rate of the heating extraction steam is controlled by the heating extraction steam quick-opening valve.

[0010] A connecting pipeline will be added to the heating steam extraction pipelines of Unit 1 and Unit 2, and a condensate interconnection system will be added between the low-pressure inlet of Unit 1 and the low-pressure outlet of Unit 2 on the condensate side.

[0011] When the heat load demand is not high, the high back pressure unit diverts part of the steam from the low pressure cylinder of Unit 1 to the low pressure cylinder of Unit 2 to do work through the heating extraction steam connection pipe.

[0012] When the heat load demand is high, some of the steam inlet of the low-pressure cylinder of Unit 2 is diverted to the low-pressure cylinder of Unit 1 to do work. The steam exhaust from the low-pressure cylinder of Unit 1 is used to further heat the circulating water of the heating network, and a low-quality heat source is used for heating.

[0013] Overall, compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] This invention is a flexible adjustment system designed and developed by modifying the heating pipeline system to enable high back-pressure units to simultaneously meet the needs of heat and electricity loads, and it also has the functions of heating, power generation and peak shaving. Attached Figure Description

[0015] Figure 1 The system of the present invention is shown in the figure;

[0016] Figure 2 This is a control strategy diagram for the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] In this example, high back pressure units have many advantages, such as strong heating capacity, high heating efficiency, improved thermal cycle efficiency, reduced coal consumption for power generation, and energy saving.

[0019] However, high back-pressure units also have problems that need to be solved. Among them, the electrical load and thermal load of high back-pressure units have a strongly coupled linear relationship. When the heating demand is low, the power generation of the unit is limited by the thermal load.

[0020] The heating pipeline renovation system is a flexible adjustment system designed and developed to enable high back-pressure units to simultaneously meet the needs of heat and electricity loads, and it also has the functions of heating, power generation and peak shaving.

[0021] Unit 1 is a high back pressure retrofit unit, with the original circulating water replaced by the return water from the heating network. Unit 2 is an extraction condensing unit.

[0022] The return water from the heat exchange network is first heated by the condenser of Unit 1 (high back pressure unit), and then flows through the respective heating extraction steam pipelines of Units 1 and 2 to the heat exchange network heaters for secondary heating. The flow rate of the heating extraction steam is controlled by a quick-opening valve. It is now proposed to add a connecting pipeline to the heating extraction steam pipelines of Units 1 and 2, and to add a condensate interconnection system between the #1 low-pressure heater inlet of Unit 1 and the #2 low-pressure heater outlet of Unit 2 on the condensate side.

[0023] After the modification, when the heat load demand of Unit 1 is not high, some of the steam entering the low-pressure cylinder of Unit 1 is diverted to the low-pressure cylinder of Unit 2 to do work through the heating extraction steam connection pipe, which solves the bottleneck problem that the electrical load of Unit 1 is limited by the heat load.

[0024] When the heat load demand is high, some of the steam inlet of the low-pressure cylinder of Unit 2 is diverted to the low-pressure cylinder of Unit 1 to do work. The exhaust steam from the low-pressure cylinder of Unit 1 is used to further heat the circulating water of the heating network. By using the lowest quality heat source for heating as much as possible, the heating economy of the whole plant is improved.

[0025] When heat load demand is low and electricity load demand is high:

[0026] Since Unit 1 is a high back-pressure unit, the heat supply and power generation of the back-pressure unit have a strong, nearly linear relationship. When the heat demand is low, the electrical load needs to be reduced. In this case, the quick-opening valve for heating of Unit 1 can be closed slightly, while the opening of the quick-opening valve for heating of Unit 2 can be increased. This allows some of the steam that originally entered the low-pressure cylinder of Unit 1 to do work to enter the low-pressure cylinder of Unit 2 through the heating extraction steam connection pipe and continue to do work.

[0027] In addition, since the condensate parameters at the low-pressure inlet of Unit 1's high back pressure unit #1 are similar to the condensate temperature at the outlet of Unit 2's low-pressure heater, a condensate connecting pipeline was added. The condensate connecting valves (2_1, 1_2) were opened, and the condensate connecting valves (1_1, 2_2) were closed. The condensate at the outlet of Unit 2's low-pressure heater was then returned to the low-pressure inlet of Unit 1's #1 via the booster pump in the connecting pipeline, thus controlling the condenser water level of Unit 1 within the normal range.

[0028] When heat load demand is high and electrical load demand is low:

[0029] Close the quick-opening valve for heating of Unit 2 and increase the opening of the quick-opening valve for heating of Unit 1. This allows some of the steam that originally entered the low-pressure cylinder of Unit 2 to do work to enter the low-pressure cylinder of Unit 1 through the heating extraction steam connection pipe to continue doing work. The steam discharged from the low-pressure cylinder is used for heating, maximizing the use of low-quality heat sources for heating and improving the overall heating economy of the plant.

[0030] Open the condensate connection valves (1_1, 2_2) and close the condensate connection valves (2_1, 1_2). Use the booster pump in the connection pipe to recover the condensate from the No.1 low-pressure inlet of Unit 1 to the No.2 low-pressure outlet of Unit 2, and control the condenser water level of Unit 2 within the normal range.

[0031] In Mode 1, when the heating extraction steam connection shut-off valve is closed, the heating quick-opening valve of Unit 1 is fully open, and Unit 1 carries the basic heat load (electric load). The heating quick-opening valve of Unit 2 adjusts the heating network outlet temperature T2.

[0032] In Mode 2, when the heating extraction steam connection shut-off valve is open, the heating quick-opening valves of Units 1 and 2 jointly regulate the heating network water temperature T1 at the condenser outlet of Unit 1, and the heater pressure reducing valve regulates the heating network outlet temperature T2.

[0033] Through the above modifications, both heating and power generation capabilities can be guaranteed during the heating season, making the two units more flexible in heating and power generation and better able to meet the current electricity market's demand for thermal power plants.

[0034] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-type heating unit group coordinated control device, including Unit 1 and Unit 2; The No. 1 unit is a high back pressure retrofit unit, with the original circulating water replaced by the return water from the heating network; the No. 2 unit is an extraction condensing unit. After the return water of the heating network is heated in the first stage by the condenser of the high back pressure unit of Unit 1, it is then heated in the second stage by the heating network heater through the respective heating extraction steam pipelines of Unit 1 and Unit 2. The flow rate of the heating extraction steam is controlled by the heating quick-opening valve. A heating extraction steam connection pipe is added between the heating extraction steam pipelines of Unit 1 and Unit 2. When the heat load demand of the high back pressure unit is not high, part of the steam entering the low pressure cylinder of Unit 1 is diverted to the low pressure cylinder of Unit 2 to do work through the heating extraction steam connection pipe. When the heat load demand is high, some of the steam inlet of the low-pressure cylinder of Unit 2 is diverted to the low-pressure cylinder of Unit 1 to do work, and the steam exhaust from the low-pressure cylinder of Unit 1 is used to further heat the circulating water of the heating network. When the heat load demand is low and the electricity load demand is high, the heating quick-opening valve of Unit 1 can be closed and the opening of the heating quick-opening valve of Unit 2 can be increased, so that some of the steam that originally entered the low-pressure cylinder of Unit 1 to do work can enter the low-pressure cylinder of Unit 2 through the heating extraction steam connection pipe to continue to do work. Since the condensate parameters at the low-pressure inlet of Unit 1 are similar to the condensate temperature at the low-pressure outlet of Unit 2, a condensate interconnection system is added between the low-pressure inlet of Unit 1 and the low-pressure outlet of Unit 2 on the condensate side. The condensate interconnection system includes condensate interconnection valve one (2_1), condensate interconnection valve two (1_1), condensate interconnection valve three (2_2) and condensate interconnection valve four (1_2); Open condensate connection valve one (2_1) and condensate connection valve four (1_2), close condensate connection valve two (1_1) and condensate connection valve three (2_2), and use the booster pump through the connection pipe to recover the condensate from the low pressure heater outlet of Unit 2 to the low pressure heater inlet of Unit 1, and control the condenser water level of Unit 1 within the normal range. When the heat load demand is high and the electricity load demand is low, the heating quick-opening valve of Unit 2 is closed and the opening of the heating quick-opening valve of Unit 1 is increased. This allows some of the steam that originally entered the low-pressure cylinder of Unit 2 to do work to enter the low-pressure cylinder of Unit 1 through the heating extraction steam connection pipe to continue doing work. The steam from the low-pressure cylinder is then discharged for heating, maximizing the use of low-quality heat sources for heating. Open condensate connection valve 2 (1_1) and condensate connection valve 3 (2_2), close condensate connection valve 1 (2_1) and condensate connection valve 4 (1_2), and use the booster pump in the connection pipe to recover the condensate from the low pressure inlet of Unit 1 to the low pressure outlet of Unit 2, thereby controlling the condenser water level of Unit 2 within the normal range.

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