Steam condensate recycling device

Abstract

The utility model provides a steam condensate recycling device. The device comprises a steam condensate generating unit, a steam condensate collecting unit and a deoxidizing unit, the steam condensate generating unit is connected with the steam condensate collecting unit through a first pipeline and used for conveying steam condensate formed by the steam condensate generating unit to the steam condensate collecting unit. The steam condensate collecting unit is connected with the deoxidizing unit through a second pipeline and used for conveying steam condensate collected by the steam condensate collecting unit to the deoxidizing unit. By adopting the device, the steam condensate can be used as make-up water under the normal operation working condition of the deaerator by utilizing the heat of the steam condensate for deaerating, and desalted water is only used under the driving working condition, so that the use amount of the desalted water is greatly reduced, and the heat of the steam condensate is also recycled in the deaerating process.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical industry, and particularly relates to a steam condensate recovery and utilization device. Background Art

[0002] Currently, turbine seal leakage and other steam in chemical plants are typically treated simply with a seal cooler, cooling the leaked gas before discharging it on-site. Individual plants in the industry will improve their condensate recovery systems based on their specific needs.

[0003] CN216043928U discloses a condensate recovery device comprising a liquid storage tank, a condensate recovery pipeline, and a pipeline pump. The condensate recovery pipeline's inlet is connected to the liquid storage tank, and its outlet is connected to the condensate pipe network. The pipeline pump is located on the condensate recovery pipeline. The device also includes an overflow pipe, the inlet of which is connected to the liquid storage tank. The distance between the inlet of the condensate recovery pipeline and the bottom of the liquid storage tank is smaller than the distance between the inlet of the overflow pipe and the bottom of the liquid storage tank. The overflow pipe has a first U-shaped bend. The U-shaped opening of the first U-shaped bend faces upward, and the lowest point of the bend at its lower end is vertically located below the liquid storage tank. This device is primarily used to recover condensate generated by the seal cooler of a back-pressure steam turbine. It has the advantages of high efficiency, ease of operation, environmental protection, and low cost.

[0004] CN112484007B discloses a series-connected pneumatic steam condensate continuous recovery device and condensate recovery method. The recovery device includes a normal-pressure flash tank, a condensate buffer collection tank, a first valve, a second valve, a third valve, a pressure relief pipe, and a fourth valve. The normal-pressure flash tank has a steam outlet at the top, a first condensate output port at the bottom, and a steam condensate input port at the side. The condensate buffer collection tank is arranged below the normal-pressure flash tank and its top is connected to the first condensate output port via a connecting pipe. The present invention eliminates the condensate pump and realizes continuous recovery of steam condensate by utilizing the normal-pressure flash tank and the condensate buffer collection tank connected in series up and down, thereby improving the economy and operational flexibility of the equipment, reducing noise, saving floor space, and effectively solving the problem of recovering intermittent or continuous steam condensate with small or medium flow in chemical plants. At the same time, the vertical arrangement of the normal-pressure flash tank and the condensate buffer collection tank is conducive to buffering the condensate output and improving the stability of the condensate output.

[0005] CN114777092A discloses a green condensate heat recovery system and a green steam condensate heat recovery method, comprising: a condensate precooler for precooling the introduced steam condensate; a condensate cooler for further cooling the steam condensate after being cooled; a heat pump, one side of which is connected to the condensate precooler and the condensate cooler and absorbs heat; a booster pump for passing part of the precooled condensate into the condensate cooler and part into a steam generator; and a steam booster device connected to the steam generator for boosting and outputting the steam generated by the steam generator.

[0006] Yet these recovery devices and methods are not suitable for the recycling of the steam condensate that the steam seal cooler produces in chemical plant.At present, these condensed waters (steam condensate) mainly adopt the mode of local discharge.

[0007] Therefore, the current prior art mainly has the following shortcomings:

[0008] 1. No specific method or device is proposed for recycling the steam condensate generated by the steam seal cooler in the chemical plant;

[0009] 2. Based on whether the energy of steam condensate is recovered, existing steam condensate recovery technologies disclosed in patents (applications) such as CN216043928U, CN112484007B, and CN114777092A can be mainly divided into two categories: 1) those that cannot recover the energy of steam condensate and directly send the recovered steam condensate to the condensate pipe network, resulting in energy waste; and 2) those that recover the energy of steam condensate and use it to generate steam again, but the equipment required is complex and costly, making it difficult to increase the equipment. Utility Model Content

[0010] In view of this, and in response to the above-mentioned problems existing in the prior art, the present invention provides a device for recycling steam condensate. The device of the present invention can realize the recycling of the heat of steam condensate and the steam condensate itself.

[0011] The purpose of this utility model is mainly achieved through the following technical solutions.

[0012] The utility model provides a device for recycling steam condensate, which comprises a steam condensate generating unit, a steam condensate collecting unit and a deoxidizing unit.

[0013] The steam condensate generating unit includes a steam turbine shaft seal leakage source, a motive steam source, a steam jet pump, a primary seal cooler, and a secondary seal cooler; wherein the steam turbine shaft seal leakage source is connected to the steam inlet of the primary seal cooler, the cooling steam inlet of the steam jet pump is connected to the cooling steam outlet of the primary seal cooler, the motive steam inlet of the steam jet pump is connected to the motive steam source, and the outlet of the steam jet pump is connected to the secondary seal cooler;

[0014] The steam condensate collection unit includes a condensate tank and a condensate pump, wherein the condensate tank is connected to the secondary drain port of the secondary gas seal cooler through a first pipeline, and is used to collect steam condensate from the secondary gas seal cooler;

[0015] The deoxidation unit includes a deoxidizer and a thermal steam source for providing steam to the deoxidizer; the deoxidizer is connected to the condensate tank via the condensate pump and is used to deoxidize the steam condensate from the condensate tank.

[0016] In some embodiments of the present invention, the turbine shaft seal leakage source includes air compressor turbine shaft seal leakage, refrigerator turbine shaft seal leakage, and circulating water pump turbine shaft seal leakage.

[0017] In some embodiments of the present invention, the steam condensation generating unit also includes a liquid-sealed U-shaped tube, wherein one end of the liquid-sealed U-shaped tube is connected to the first-level drain port of the first-level air-sealed cooler, and the other end is connected to the condensate tank, and a liquid replenishing port is provided at the bottom of the liquid-sealed U-shaped tube.

[0018] In some embodiments of the present invention, the other end of the liquid-sealed U-shaped tube is connected to the condensate tank via a first pipeline.

[0019] In some embodiments of the present invention, the steam condensate collecting unit further includes a reflux pipe, one end of which is connected to the outlet of the condensate pump, and the other end of which is connected to the condensate tank.

[0020] In some embodiments of the present invention, a position of the first-level drain port of the first-level gas seal cooler and a position of the second-level drain port of the second-level gas seal cooler are higher than the top of the condensate tank.

[0021] In some embodiments of the present invention, the position where the first pipeline is connected to the condensate tank is higher than the position where the return pipe is connected to the condensate tank.

[0022] In some embodiments of the present invention, the reflux pipe is connected to the upper middle section of the condensate tank body.

[0023] In some embodiments of the present invention, the inlet of the condensate pump is connected to the bottom of the condensate tank, the outlet is connected to the top of the horizontal tank body of the deaerator, and the outlet of the thermal steam source is connected to the middle and upper part of the vertical tank body of the deaerator.

[0024] In some embodiments of the present invention, the deoxygenation unit further includes a desalted water source connected to the deoxygenator.

[0025] In some embodiments of the present invention, the deaerator is connected to the boiler feed water pipeline.

[0026] The utility model has the following advantages:

[0027] 1. It realizes the recycling of turbine shaft seal leakage and solves the problem of ineffective utilization of low-grade thermal energy. The steam condensate recycling device of the utility model can pre-cool the condensate to below 100°C, reducing the probability of pipeline vibration caused by two-phase flow blockage in the condensate system;

[0028] 2. The steam condensate recovery and utilization device of the present invention can transport steam condensate to the deaerator as make-up water under normal operating conditions of the deaerator, and use the heat of the steam condensate and a small amount of additional steam to deoxygenate the steam condensate, thereby reducing the amount of desalted water used. At the same time, the heat of the steam condensate can also be recovered and utilized; the motive steam provided by the motive steam source is also recovered and utilized together with the steam condensate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of an embodiment of the steam condensate recovery and utilization device of the present invention;

[0030] Figure 2 This is a schematic diagram of a steam condensate recovery and utilization device according to Example 1 of the present utility model;

[0031] Figure 3 This is a schematic diagram of the steam condensate recovery and utilization device of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention.

[0033] In the first aspect, the utility model provides a device for recycling steam condensate, which includes: a steam condensate generating unit, a steam condensate collecting unit and a deoxygenation unit; the steam condensate generating unit is connected to the steam condensate collecting unit through a pipeline, and the steam condensate collecting unit is connected to the deoxygenation unit through a pipeline.

[0034] Figure 1 An embodiment of the steam condensate recovery and utilization device of the present utility model is shown.

[0035] Reference Figure 1 The device of the utility model includes: a steam condensate generating unit, a steam condensate collecting unit and a deoxidation unit.

[0036] The steam condensate generating unit includes a steam turbine shaft seal leakage source 11, a motive steam source 12, a steam jet pump 13, a primary seal cooler 14, and a secondary seal cooler 15; wherein the steam turbine shaft seal leakage source 11 is connected to the steam inlet of the primary seal cooler 14, the cooling steam inlet of the steam jet pump 13 is connected to the cooling steam outlet of the primary seal cooler 14, the motive steam inlet of the steam jet pump 13 is connected to the motive steam source 12, and the outlet of the steam jet pump 13 is connected to the secondary seal cooler 15;

[0037] The steam condensate collection unit includes a condensate tank 21 and a condensate pump 22, wherein the condensate tank 21 is connected to the secondary drain port of the secondary gas seal cooler 15 through a first pipeline 101, and is used to collect steam condensate from the secondary gas seal cooler 15;

[0038] The deoxidation unit includes a deoxidizer 31 and a thermal steam source 32 for providing steam to the deoxidizer 31 ; the deoxidizer 31 is connected to the condensate tank 21 via a condensate pump 22 and is used to deoxidize the steam condensate from the condensate tank 21 .

[0039] In some embodiments, the turbine shaft seal leakage source 11 includes but is not limited to air compressor turbine shaft seal leakage, refrigerator turbine shaft seal leakage, and circulating water pump turbine shaft seal leakage.

[0040] In some embodiments, the turbine shaft seal leakage source 11 comes from a petrochemical plant.

[0041] In some embodiments, the motive steam provided by the motive steam source 12 enters the steam jet pump 13 to provide power, which is used to drive the steam coming out of the turbine shaft seal leakage source 11 to pass through the first-stage gas seal cooler 14, the steam jet pump 13 and the second-stage gas seal cooler 15 in sequence to form steam condensate and then enter the condensate tank 21.

[0042] In some embodiments, the secondary gas seal cooler 15 is further connected to a first venting pipeline for discharging non-condensable gas in the secondary gas seal cooler 15 .

[0043] In some embodiments, the steam condensation generating unit further includes a liquid-sealed U-shaped tube 103, wherein one end of the liquid-sealed U-shaped tube 103 is connected to the first-level drain port of the first-level air-sealed cooler 14, and the other end is connected to the condensate tank 21, and a liquid infusion port is provided at the bottom of the liquid-sealed U-shaped tube 103. Before the device is operated, liquid is infused through the liquid infusion port to form a liquid seal in the U-shaped tube 103. Part of the condensate generated in the first-level air-sealed cooler 14 enters the liquid-sealed U-shaped tube to act as a liquid seal, preventing air from entering the first-level air-sealed cooler 14 and affecting the negative pressure environment of the first-level air-sealed cooler 14; when there is too much condensate in the U-shaped tube, the excess condensate overflows into the first pipeline 101. The U-shaped mouth of the U-shaped tube 103 faces vertically upward.

[0044] In some embodiments, the other end of the liquid-sealed U-shaped tube 103 is connected to the condensate tank 21 via the first pipeline 101 .

[0045] In some embodiments, the steam condensate collection unit further includes a reflux pipe 104, one end of which is connected to the outlet of the condensate pump 22 and the other end of which is connected to the condensate tank 21, for regulating the flow of steam condensate into the deaerator 31. The reflux tank 104 can be opened or closed, depending on the actual operating conditions.

[0046] In some embodiments, the first-level drain port position of the first-level air-sealed cooler 14 and the second-level drain port position of the second-level air-sealed cooler 15 are higher than the top of the condensate tank 21. The pressure difference generated by the height difference is reasonably utilized to allow the steam condensate in the first-level air-sealed cooler 14 and the second-level air-sealed cooler 15 to flow into the condensate tank 21, without the need to install an additional pump, thereby saving costs.

[0047] In some embodiments, the position where the first pipeline 101 is connected to the condensate tank 21 is higher than the position where the return pipe 104 is connected to the condensate tank. The outlet position refers to the interface position where the liquid flows out of the first pipeline 101 or the return pipe 104 and enters the condensate tank 21.

[0048] In some embodiments, the return pipe 104 is connected to the upper middle section of the condensate tank 21 .

[0049] In some embodiments, a second venting pipeline is connected to the top of the condensate tank 21 to maintain the interior of the condensate tank 21 at normal pressure.

[0050] In some embodiments, the inlet of the condensate pump 22 is connected to the bottom of the condensate tank 21, the outlet is connected to the top of the horizontal tank body of the deaerator 31, and the outlet of the thermal steam source 32 is connected to the upper middle section of the vertical tank body of the deaerator 31. The condensate pump 22 is installed on the second pipeline 102.

[0051] In some embodiments, the deoxygenation unit further includes a desalted water source 33 connected to the deoxygenator 31. When the amount of steam condensate entering the deoxygenator 31 is insufficient, the desalted water source 33 provides desalted water to the deoxygenator 31 for deoxygenation.

[0052] In some embodiments, the deaerator 31 is connected to the boiler feed water pipeline for delivering the deoxygenated steam condensate in the deaerator 31 to the boiler device.

[0053] In some embodiments, the deaerator 31 is connected to a waste gas recovery pipeline for discharging the waste gas in the deaerator 31 through the waste gas recovery pipeline.

[0054] In some embodiments, the cooling water feed water passes through the primary gas seal cooler 14 and the secondary gas seal cooler 15 in sequence for heat exchange with the steam entering the primary gas seal cooler 14 and the secondary gas seal cooler 15 .

[0055] In some embodiments, the deaerator 31 further includes a sewage outlet.

[0056] Reference Figure 1 As shown, the valves and instruments involved in the present invention are conventional in the field, and the operation method is conventional in the field, which will not be described here.

[0057] In chemical plants, a steam seal cooler is needed to collect turbine shaft seal leakage and a deaerator is used to remove oxygen and other non-condensable gases from water. The steam condensate produced by the steam seal cooler has low impurities and high temperature. Discharging it on site will waste energy and cause leakage of on-site equipment. The utility model utilizes the heat of this part of the steam condensate and a small amount of additional steam to use the steam condensate as supplementary water for deoxygenation under normal operating conditions of the deaerator. The desalted water is only used under starting conditions, which not only greatly reduces the amount of desalted water used, but also the heat of the steam condensate can be recycled in the deoxygenation process.

[0058] The preferred embodiments of the present invention are described in detail below to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0059] Example 1

[0060] Reference Figure 2 First, the cooling water supply is turned on, and the cooling water forms a cooling water supply-first-level air seal cooler-second-level air seal cooler-cooling water return cycle; the liquid is replenished at the liquid replenishing port of the U-shaped tube 103, and the U-shaped tube 103 forms a liquid seal.

[0061] The compressor turbine shaft seal leakage and the refrigerator turbine shaft seal leakage enter their respective primary seal coolers 14, and the motive steam provided by the motive steam source 12 enters the corresponding steam jet pump 13. After the primary cooling in the primary seal cooler 14, the turbine shaft seal leakage enters the steam jet pump 13 and, together with the motive steam entering the steam jet pump 13, enters the secondary seal cooler 15 for secondary cooling.

[0062] The steam condensate obtained by the second cooling enters the condensate tank 21 through the first pipeline 101 due to the pressure generated by the height difference between the secondary drain port (working pressure 0.108 MPa) of the secondary air-sealed cooler 15 and the condensate tank 21, and the non-condensable gas in the primary air-sealed cooler 14 is discharged from the first vent pipeline; the condensate discharged from the primary drain port (working pressure 0.095 MPa) of the primary air-sealed cooler 14 enters the liquid-sealed U-shaped pipe 103 and enters the condensate tank 21 through the first pipeline 101. The temperature of the steam condensate in the condensate tank 21 is 80°C. The second vent pipeline is opened to maintain the internal pressure of the condensate tank 21 at normal pressure, and the steam condensate output is 1584.4 kg / h; a part of the steam condensate in the condensate tank 21 is pumped out by the condensate pump 22 with a lift of 20 meters, and the steam condensate is pumped into the deaerator 31 through the top tank port of the horizontal tank body of the deaerator 31 connected to the second pipeline 102.

[0063] Thermal steam source 3 provides 0.4 MPaG steam, which enters deaerator 31 from the middle and upper section of its vertical tank for deoxygenation, producing deoxygenated steam condensate. Deaerator 31 operates at a pressure of 0.02 MPaG and a temperature of 105°C. This deoxygenated steam condensate enters the boiler unit through the boiler feedwater line to produce steam, enabling the recycling of the steam condensate. Furthermore, because the steam condensate reaches a temperature of 80°C and carries heat, it reduces steam usage in the deaerator unit. Furthermore, the motive steam provided by motive steam source 12 is also recycled along with the steam condensate.

[0064] Comparative Example 1

[0065] Reference Figure 3 The implementation scheme of this comparative example differs from that of Example 1 in that only the compressor turbine shaft seal experiences leakage, and this comparative example lacks a deaerator. Steam condensate pumped from condensate tank 21 is directed directly into the existing condensate main tank or condensate main pipe network on-site. This results in significant energy waste. Furthermore, after a period of operation, leakage began to occur in the on-site equipment. The steam condensate output of this comparative example was 1600 kg / h.

[0066] As can be seen from Example 1 and Comparative Example 1, the heat from turbine shaft seal leakage and motive steam is recovered and utilized by the recovery device of the present invention. Simultaneously, the steam condensate generated by cooling the turbine shaft seal leakage and motive steam serves as make-up water for the deaerator, enabling the recovery of the condensate and saving desalted water and steam usage in the deaerator unit. However, the technical solution in Comparative Example 1 fails to achieve heat and condensate recovery, resulting in significant resource waste.

[0067] Any numerical value mentioned in this utility model includes all values that increase by one unit each time from the lowest value to the highest value if there is only an interval of two units between any minimum value and any maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is stated to be 50-90, it means in this specification that 51-89, 52-88... and 69-71 and 70-71 are specifically listed. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 can be appropriately considered as one unit. These are just some special examples. In this application, in a similar manner, all possible combinations of numerical values between the listed lowest value and the listed highest value are considered to have been disclosed.

[0068] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as provided within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. Steam condensate recovery and utilization device, characterized in that: The device comprises: a steam condensate generating unit, a steam condensate collecting unit and a deoxidizing unit; The steam condensate generating unit comprises a steam turbine shaft seal leakage source (11), a motive steam source (12), a steam jet pump (13), a primary seal cooler (14) and a secondary seal cooler (15); wherein the steam turbine shaft seal leakage source (11) is connected to the steam inlet of the primary seal cooler (14), the cooling steam inlet of the steam jet pump (13) is connected to the cooling steam outlet of the primary seal cooler (14), the motive steam inlet of the steam jet pump (13) is connected to the motive steam source (12), and the outlet of the steam jet pump (13) is connected to the secondary seal cooler (15); The steam condensate collecting unit comprises a condensate tank (21) and a condensate pump (22), wherein the condensate tank (21) is connected to the secondary drain port of the secondary gas seal cooler (15) through a first pipeline (101) and is used to collect steam condensate from the secondary gas seal cooler (15); The deoxidation unit comprises a deoxidizer (31) and a thermal steam source (32) for providing steam to the deoxidizer (31); the deoxidizer (31) is connected to the condensate tank (21) via the condensate pump (22) and is used for deoxidizing the steam condensate from the condensate tank (21).

2. The device according to claim 1, characterized in that The turbine shaft seal leakage source (11) includes air compressor turbine shaft seal leakage, refrigerator turbine shaft seal leakage, and circulating water pump turbine shaft seal leakage.

3. The device according to claim 1 or 2, characterized in that The steam condensation generating unit further comprises a liquid-sealed U-shaped tube (103), wherein one end of the liquid-sealed U-shaped tube (103) is connected to the first-level drain port of the first-level gas-sealed cooler (14), and the other end is connected to the condensate tank (21), and a liquid replenishing port is provided at the bottom of the liquid-sealed U-shaped tube (103).

4. The device according to claim 3, characterized in that The other end of the liquid-sealed U-shaped tube (103) is connected to the condensate tank (21) via a first pipeline (101).

5. The device according to claim 1 or 2, characterized in that The steam condensate collection unit further comprises a return pipe (104), one end of which is connected to the outlet of the condensate pump (22), and the other end of which is connected to the condensate tank (21).

6. The device according to claim 3, characterized in that The position of the first-level drain port of the first-level gas-sealed cooler (14) and the position of the second-level drain port of the second-level gas-sealed cooler (15) are higher than the tank top of the condensate tank (21).

7. The device according to claim 5, characterized in that The position where the first pipeline (101) is connected to the condensate tank (21) is higher than the position where the return pipe (104) is connected to the condensate tank (21), and the return pipe (104) is connected to the upper middle section of the condensate tank (21).

8. The device according to claim 1 or 2, characterized in that The inlet of the condensate pump (22) is connected to the bottom of the condensate tank (21), the outlet is connected to the top of the horizontal tank body of the deaerator (31), and the outlet of the thermal steam source (32) is connected to the middle and upper section of the vertical tank body of the deaerator (31).

9. The device according to claim 1 or 2, characterized in that The deoxygenation unit further comprises a desalted water source (33) connected to the deoxygenator (31).

10. The device according to claim 1 or 2, characterized in that The deaerator (31) is connected to the boiler feed water pipeline.

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