阅读说明：本技术 一种基于中调门参调的宽负荷中压供热方式 (Wide-load medium-pressure heating mode based on parameter adjustment of medium-adjustment door ) 是由 钟国炼 廖源 谭锐 朱佩锋 陈国武 辜军 殷戈 米斌 曾娅 黄彪 韦龙飞 施浩 于 2020-12-07 设计创作，主要内容包括：本发明涉及一种基于中调门参调的宽负荷中压供热方式。首先,统计电厂对应机组全年平均负荷,根据热力计算找出在该平均负荷下接近供热抽汽参数的位置,以平均负荷作为设计点,以该位置作为供热抽汽口。在设计点负荷以上,抽汽压力无需进行压力调节；在设计点负荷以下,通过中调门调整抽汽压力,避免抽汽压力参数不满足要求。其次,另置二号再热器,抽出的蒸汽不经过再热管道,直接进入二号再热器。供热时,经二号再热器加热,提高蒸汽温度后用于工业供热。非供热时,从二号再热器出来的蒸汽经减温减压后,回到再热冷段管道。本发明针对中压供热提出一个新方式,解决高品质蒸汽浪费、供热参数不足的问题,实现高效、可靠、持续、可调峰供热。(The invention relates to a wide-load medium-pressure heating mode based on medium-pressure regulating door parameter regulation. Firstly, the annual average load of a corresponding unit of a power plant is counted, the position close to a heat supply steam extraction parameter under the average load is found out according to thermal calculation, the average load is used as a design point, and the position is used as a heat supply steam extraction port. Above the design point load, the extraction pressure does not need to be adjusted; and (3) adjusting the steam extraction pressure through a middle adjusting valve below the load of a design point to avoid that steam extraction pressure parameters do not meet requirements. Secondly, a second reheater is additionally arranged, and extracted steam directly enters the second reheater without passing through a reheating pipeline. During heat supply, the steam is heated by a second reheater, and the steam is used for industrial heat supply after the temperature of the steam is increased. When the heat is not supplied, the steam from the second reheater returns to the reheating cold section pipeline after being subjected to temperature and pressure reduction. The invention provides a new mode aiming at medium-pressure heat supply, solves the problems of high-quality steam waste and insufficient heat supply parameters, and realizes high-efficiency, reliable, continuous and peak-adjustable heat supply.)

1. The utility model provides a wide load middling pressure heating mode based on well accent door is joined in marriage and is transferred which characterized in that: the average load of the power plant unit is counted, and the position closest to the heat supply steam extraction parameter under the average load is found out according to the thermal calculation; the average load is used as a design point, the position is used as a heating steam extraction port, and the steam extraction pressure is adjusted by an intermediate throttle arranged on a reheating section pipeline below the load of the design point.

2. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 1, is characterized in that: the power plant unit is provided with No. two reheaters, No. two reheater steam inlet pipe says and is connected with heat supply extraction steam port, and No. two reheaters play steam pipe says and is connected with the heat supply pipeline.

3. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 2, is characterized in that: and the second reheater steam outlet pipeline is also connected with the reheating cold section pipeline.

4. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 3, is characterized in that: and a temperature and pressure reducer and a stop valve are arranged on a pipeline between the second reheater steam outlet pipeline and the reheating cooling section pipeline.

5. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 4, is characterized in that: and the heat supply pipeline is provided with a steam extraction check valve, a steam extraction regulating valve and a steam extraction shutoff valve.

6. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 5, is characterized in that: the method for adjusting the extraction pressure by using the middle regulating valve comprises the following steps: gradually reducing the opening degree of the middle adjusting valve until the pressure of the heat supply steam extraction port reaches a heat supply requirement value, and supplying steam to the outside; and the steam extraction flow is adjusted through the steam extraction adjusting valve.

7. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 1, is characterized in that: the power plant unit is including the high pressure jar, intermediate pressure jar and the low pressure jar that connect gradually, the reheat steam export and the cold section pipe connection of reheating of high pressure jar, cold section pipe connection of reheating and reheater entry linkage, reheater export and the hot section pipe connection of reheating, the hot section pipe connection of reheating is connected with the intermediate pressure jar.

8. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 7, is characterized in that: and the heat supply steam extraction port is positioned on the high-pressure cylinder.

9. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 8, is characterized in that: an inner cylinder of the high-pressure cylinder is provided with a steam extraction channel at a heat supply steam extraction port, an outer cylinder of the high-pressure cylinder is provided with an opening at a corresponding position, the outer side of the outer cylinder is provided with a connecting platform in a surfacing mode along the circumferential direction of the opening, a steam extraction short pipe is welded on the connecting platform, and the steam extraction short pipe is connected with a steam extraction pipeline; an extraction cannula is arranged between the inner cylinder and the outer cylinder.

10. The wide-load medium-pressure heating mode based on medium-pressure door parameter adjustment according to claim 7, is characterized in that: a thrust bearing is arranged between the intermediate pressure cylinder and the low pressure cylinder, and the method for rechecking and designing the thrust of the unit during heat supply comprises the following steps: amplifying the positive thrust of the unit under the pure condensing working condition within an allowable range, and ensuring that the negative thrust is within the allowable range after the negative thrust is increased under the steam extraction working condition; the area of the thrust bearing is increased, and the lubricating oil quantity of the thrust bearing is increased simultaneously.

Technical Field

The invention relates to a wide-load medium-pressure heat supply mode based on medium-pressure door parameter adjustment, and belongs to the technical field of thermal power generation cogeneration.

Background

The cogeneration is an effective means for reducing the unit emission and improving the economic benefit of a power plant. With the vigorous development of the industries such as the biological pharmacy and the chemical engineering in China, the demand for high-parameter steam (4 MPa-7 MPa) is increasing day by day. The boiler of the large-scale thermal generator set has smaller boiler efficiency, high combustion efficiency, perfect equipment for desulfurization, denitrification and the like, strict environmental protection supervision and is a clean source for providing high-parameter steam; the large thermal generator set has high power generation efficiency and high equipment safety, and is a reliable and stable source for providing high-parameter steam. At present, a mode of providing high-parameter steam by using a large thermal power generating unit is mainly to perform temperature and pressure reduction treatment on high-quality steam or to perform punching steam extraction on a turbine reheating pipeline, but the methods have defects, such as: 1. the main steam is directly used for temperature reduction, pressure reduction and heat supply, and the economic loss is large. 2. The main steam belt is provided with a small backpressure machine, the backpressure machine is used for exhausting steam and supplying heat, the temperature and the pressure are reduced essentially, part of electric load can be recovered, the power generation efficiency of the small backpressure machine is far lower than that of a large machine set, the high-parameter small backpressure machine is made of high-temperature alloy materials the same as that of the large machine set, and the manufacturing cost is high. 3. And (3) punching holes on the reheating pipeline to extract steam, wherein the steam pressure (usually 3-5 MPa) and the temperature of the steam cannot meet the requirements, especially under the low-load working condition.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a medium-regulation door-parameter-regulation-based wide-load medium-pressure heating mode which enables a unit to have wide-load heating capacity and improves the comprehensive economy of the unit.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: a wide-load medium-pressure heat supply mode based on medium-pressure regulation door parameter regulation is characterized in that the heat supply mode counts the average load of a power plant unit and finds out the position closest to a heat supply steam extraction parameter under the average load according to heat calculation; the average load is used as a design point, the position is used as a heating steam extraction port, and the steam extraction pressure is adjusted by an intermediate throttle arranged on a reheating section pipeline below the load of the design point.

The technical scheme is further designed as follows: the power plant unit is provided with No. two reheaters, No. two reheater steam inlet pipe says and is connected with heat supply extraction steam port, and No. two reheaters play steam pipe says and is connected with the heat supply pipeline.

And the second reheater steam outlet pipeline is also connected with the reheating cold section pipeline.

And a temperature and pressure reducer and a stop valve are arranged on a pipeline between the second reheater steam outlet pipeline and the reheating cooling section pipeline.

And the heat supply pipeline is provided with a steam extraction check valve, a steam extraction regulating valve and a steam extraction shutoff valve.

The method for adjusting the extraction pressure by using the middle regulating valve comprises the following steps: gradually reducing the opening degree of the middle adjusting valve until the pressure of the heat supply steam extraction port reaches a heat supply requirement value, and supplying steam to the outside; and the steam extraction flow is adjusted through the steam extraction adjusting valve.

The power plant unit is including the high pressure jar, intermediate pressure jar and the low pressure jar that connect gradually, the reheat steam export and the cold section pipe connection of reheating of high pressure jar, cold section pipe connection of reheating and reheater entry linkage, reheater export and the hot section pipe connection of reheating, the hot section pipe connection of reheating is connected with the intermediate pressure jar.

And the heat supply steam extraction port is positioned on the high-pressure cylinder.

An inner cylinder of the high-pressure cylinder is provided with a steam extraction channel at a heat supply steam extraction port, an outer cylinder of the high-pressure cylinder is provided with an opening at a corresponding position, the outer side of the outer cylinder is provided with a connecting platform in a surfacing mode along the circumferential direction of the opening, a steam extraction short pipe is welded on the connecting platform, and the steam extraction short pipe is connected with a steam extraction pipeline; an extraction cannula is arranged between the inner cylinder and the outer cylinder.

A thrust bearing is arranged between the intermediate pressure cylinder and the low pressure cylinder, and the method for rechecking and designing the thrust of the unit during heat supply comprises the following steps: amplifying the positive thrust of the unit under the pure condensing working condition within an allowable range, and ensuring that the negative thrust is within the allowable range after the negative thrust is increased under the steam extraction working condition; the area of the thrust bearing is increased, and the lubricating oil quantity of the thrust bearing is increased simultaneously.

The invention has the beneficial effects that:

the medium-pressure heat supply mode of the invention carries out heat supply design according to average annual load, and can improve the flexibility and the economical efficiency of heat supply of the unit to the maximum extent.

The heat supply steam extraction port is arranged on the high-pressure through-flow part, the heat supply pressure is up to 4-7 MPa, the temperature can reach more than 500 ℃, and the risk of dry burning of a boiler reheater can be reduced.

When the load is lower than the design point, the steam extraction capacity of the unit can be ensured by utilizing the middle adjusting door for adjustment when the load is lower; and at high load, the middle adjusting door is fully opened, so that the throttling loss is reduced.

The annual average load is used as a design matching point, so that the heat supply parameters of the unit are just near the heat supply demand pressure in most of the year, the unit has wide load heat supply capacity, and the comprehensive economy of the unit is greatly improved.

The invention provides a new mode aiming at medium-pressure heat supply (4 MPa-7 MPa), solves the problems of high-quality steam waste and insufficient heat supply parameters, and realizes efficient, reliable, continuous and peak-adjustable heat supply.

Drawings

FIG. 1 is a schematic diagram of a medium pressure heating system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a high pressure cylinder at a heating steam extraction port in an embodiment of the invention.

In the figure: 1-a middle adjusting door, 2-a heat supply steam extraction port, 3-a thrust bearing positioning surface, 4-a thrust bearing non-positioning surface, 5-a steam extraction check valve, 6-a steam extraction adjusting valve, 7-a steam extraction shutoff valve, 8-a second reheater, 81-a reheater, 9-a temperature and pressure reducer, 10-a stop valve, 11-an inner cylinder, 12-a steam extraction insertion pipe, 13-an outer cylinder, 14-a steam extraction short pipe and 15-a steam extraction pipeline.

Detailed Description

The invention is described in detail below with reference to the figures and the specific embodiments.

Examples

As shown in fig. 1, a heating system used in the medium-pressure heating mode of this embodiment includes a high-pressure cylinder, a medium-pressure cylinder, and a low-pressure cylinder, which are connected in sequence, a thrust bearing is disposed between the medium-pressure cylinder and the low-pressure cylinder, a thrust bearing non-positioning surface 4 is disposed on one side of the thrust bearing close to the medium-pressure cylinder, and a thrust bearing positioning surface 3 is disposed on one side of the thrust bearing close to the low-pressure cylinder; the reheat steam outlet of high pressure cylinder is connected with the cold section pipeline of reheating, and the cold section pipeline of reheating is connected with reheater 81 steam inlet, and reheater steam outlet and the hot section pipeline of reheating are connected, and the hot section pipeline of reheating is connected with the intermediate pressure cylinder, is equipped with well accent door 1 on the hot section pipeline of reheating.

Be equipped with heat supply extraction steam port 2 on the high-pressure cylinder, still be provided with No. two reheaters 8 in this system, No. two reheaters 8 steam inlet pipe says and is connected with heat supply extraction steam port 2, and No. two reheaters 8 play steam pipe says and is connected with heat supply pipeline, be equipped with extraction check valve 5, extraction governing valve 6 and extraction shutoff valve 7 on the heat supply pipeline. No. two re-heaters 8 go out the steam pipeline and still pass through pipeline and reheat cold leg pipe connection, are equipped with pressure reducer 9 and stop valve 10 on the pipeline between No. two re-heaters 8 play steam pipeline and the reheat cold leg pipeline.

In the heat supply mode of the embodiment, firstly, the annual average load of the corresponding units of the power plant is counted, the position closest to the heat supply steam extraction parameter under the average load is found out according to the thermodynamic calculation, the average load is used as a design point, and the position is used as a heat supply steam extraction opening. For example, if the annual average load of a certain unit is 70%, the steam extraction pressure requirement is 4.5MPa, the pressure after the 6 th stage of high pressure is 4.6MPa and the pressure after the 7 th stage is 4.2MPa when 70% of load is obtained by thermodynamic calculation, the 6 th stage is selected as the steam extraction port. The steam extraction pressure does not need to be adjusted above the load of a design point, so that the energy loss of high-quality steam is avoided; and (3) adjusting the steam extraction pressure through the middle adjusting valve 1 below the load of a design point to avoid that steam extraction pressure parameters do not meet requirements.

Secondly, this embodiment sets up No. two reheaters 8 in the boiler furnace in addition, and the steam that takes out from heat supply extraction steam vent 2 does not pass through the reheat pipeline, directly gets into No. two reheaters 8. During heat supply, the steam is heated by a second reheater 8, and the steam is used for industrial heat supply after the temperature of the steam is increased. The advantage of doing so is that, firstly, the steam temperature is raised, and secondly, a higher steam pressure is maintained, thereby avoiding high-quality steam waste. When the heat is not supplied, the steam from the second reheater 8 returns to the reheating cold section pipeline after temperature and pressure reduction, and is converged into the reheating hot section pipeline through the boiler, and then enters the intermediate pressure cylinder.

In this embodiment, since the high-pressure cylinder is provided with the heat supply steam extraction port 2, the upper half of the cylinder needs to be provided with the pipe insertion steam extraction device, the structure is shown in fig. 2, the high-pressure inner cylinder 11 of the steam turbine is manufactured by adopting a casting process, a steam extraction channel is cast at the selected heat supply steam extraction port, and the outer side of the inner cylinder 11 is cast with a connecting flange.

The upper half of the high-pressure outer cylinder 13 is provided with a supplementary opening at the using position, a connecting platform is formed on the outer side along the circumferential direction of the opening in a surfacing mode, the connecting platform is welded with the steam extraction short pipe 14, and the steam extraction short pipe 14 is connected with the steam extraction pipeline 15 to lead out steam. In order to ensure the maintenance of the unit, the steam extraction short pipe 14 is connected with the steam extraction pipeline 15 through a flange.

An extraction pipe 12 is arranged between the inner cylinder 11 and the outer cylinder 13, and steam is extracted from the heat supply extraction port and is led out to an extraction pipeline 15 through the extraction pipe 12. The steam extraction insertion pipe 12 is sealed with the inner cylinder 11 by a flange and sealed with the outer cylinder 13 by a sealing ring.

The pressure regulation mode of the medium-pressure heating mode of the embodiment at the time of low load is as follows:

when the steam extraction pressure under the low-load working condition is not met, the steam extraction pressure is improved by closing the opening degree of the middle adjusting valve 1. The centering control door 1 is optimally designed, so that the centering control door has good adjusting performance and meets the requirement of steam extraction pressure adjustment.

Because the unit extracts steam from the high-pressure through-flow part, the pressure difference before the high-pressure extraction opening is increased, and the pressure difference of the medium-pressure part is reduced, the negative thrust of the unit under the steam extraction working condition is increased. Therefore, the heating mode must be used for rechecking and designing the thrust of the unit. The measures taken are as follows: properly amplifying the positive thrust of the unit under the pure condensing working condition within an allowable range, and ensuring that the negative thrust is also within the allowable range after the negative thrust is increased under the steam extraction working condition; the area of the thrust bearing is increased, the bearing capacity is improved, and the lubricating oil quantity of the thrust bearing is increased.

The working process of the medium-pressure heating mode of the embodiment is as follows:

during heat supply, the stop valve 10 is closed, and the steam extraction check valve 5, the steam extraction regulating valve 6 and the steam extraction shutoff valve 7 are opened. The steam is used for industrial heat supply after the temperature of the steam is increased by a second reheater 8. Above the load of a design point, the middle adjusting valve 1 does not need to be adjusted, the parameters of the heat supply steam extraction port 2 meet the heat supply requirement, and the steam extraction flow is adjusted by the steam extraction adjusting valve 6; below the designed load point, the opening degree of the middle adjusting door 1 is gradually reduced until the pressure of the heat supply steam extraction opening 2 reaches the heat supply requirement value, so that the external steam can be supplied, and the steam extraction flow is adjusted by the steam extraction adjusting valve 6.

When the heat is not supplied, the steam extraction check valve 5, the steam extraction regulating valve 6 and the steam extraction shutoff valve 7 are closed, and the shutoff valve 10 is opened. Steam comes out from the second reheater 8, returns to the reheating cold section pipeline after passing through the temperature and pressure reducer 9, is converged into the reheating hot section pipeline through the boiler, and then enters the intermediate pressure cylinder.

The technical solutions of the present invention are not limited to the above embodiments, and all technical solutions obtained by using equivalent substitution modes fall within the scope of the present invention.