Steam pipeline condensate water recovery method and system

Abstract

The invention discloses a steam pipeline condensate water recovery method and system.The steam pipeline condensate water recovery system is communicated with a drainage pipe on a steam pipeline and comprises a leading-in mechanism, a collecting mechanism, a heating mechanism and a steam exhaust mechanism, and the leading-in mechanism is used for leading in condensate water in the drainage pipe; the collecting mechanism is used for collecting the condensate water introduced by the introducing mechanism; the heating mechanism is used for heating the condensed water collected by the collecting mechanism into steam; and the steam exhaust mechanism is used for returning steam heated by the heating mechanism to the steam pipeline. The operation cost basically abuts against the saved steam cost, and the cost is extremely low; and the influence of the discharge of the condensed water on the safety and environmental protection of a production site is solved, and the device has a great practical value in actual production activities.

Description

Technical Field

[0001] The present invention relates to the technical field of condensate recovery, and particularly discloses a method and a system for recovering condensate from a steam pipeline. Background Art

[0002] Steam is a clean and safe energy carrier and is widely used in production processes. However, during the steam transportation process, heat dissipation from the pipeline to the environment inevitably occurs, including convective heat transfer and radiative heat transfer, with radiative heat transfer being the main form. After the steam in the pipeline releases the latent heat of vaporization, it becomes saturated condensate at the same temperature. Since the operating pressure of the steam is greater than atmospheric pressure, the heat carried by the condensate can reach about 25% of the total heat of the corresponding steam. Therefore, it is highly necessary to recover the condensate and the heat it carries.

[0003] In addition, the disadvantages of discharging condensate are as follows:

[0004] 1) The discharge of pipeline condensate is generally directly to the atmosphere, wasting energy.

[0005] 2) The discharge of condensate affects the safety and environment of the production site.

[0006] 3) The condensate splashes onto equipment and pipelines, which will cause corrosion or mildew to these equipment and pipelines.

[0007] Currently, condensate recovery technologies can be roughly divided into two types: open recovery systems and closed recovery systems.

[0008] Main technical solutions for condensate recovery:

[0009] 1. Open recovery system

[0010] The open recovery system recovers condensate into the feed water tank of the boiler, and the condensate collection water tank is open to the atmosphere. When the pressure of the condensate is low and it cannot reach the reuse site by its own pressure, only a high-temperature water pump can be used to pump the condensate.

[0011] The advantages of this system are simple equipment, convenient operation, and low initial investment. However, the system occupies a large area, has poor economic benefits, causes relatively large environmental pollution, and since the condensate is directly in contact with the atmosphere, the dissolved oxygen concentration in the condensate increases, making it prone to equipment corrosion. This system is suitable for small-scale steam supply systems.

[0012] 2. Closed recovery system

[0013] The closed recovery system is a system where the condensate collection tank and all pipelines are under constant positive pressure, and the entire system is closed. The condensate is directly recovered to the boiler, and the recovery temperature of the condensate is only lost in the cooling part of the pipe network. Due to the closure, the water quality is guaranteed, and the water treatment cost of the water recovered to the boiler is reduced. Its advantages are good economic benefits of condensate recovery and long working life of the equipment, but the initial investment of the system is relatively large and the operation is inconvenient.

[0014] 3. Expansion heat exchange recovery method

[0015] The technical feature of the expansion heat recovery method is to make full use of the exhaust heat of condensed water. On the one hand, through expansion flash evaporation, low-pressure steam is generated and sent to low-pressure steam users. On the other hand, through heat exchange through the heat exchanger, the temperature of high-temperature condensed water is used to heat the boiler feed water (economizer), and the high-temperature condensed water can also be used as boiler supplementary water. The disadvantage is that the equipment layout is complicated, flash evaporation still exists, and the thermal energy utilization rate is low.

[0016] 4. Closed pump into boiler method

[0017] The closed pump-into-boiler method does not install a steam trap in the steam-using equipment, and then uses a positive displacement pump or an ejector to input all the condensed water, which is a mixture of steam and water, into the boiler. However, the equipment has a low thermal energy utilization rate and is limited by the capacity of the compressor. It is only suitable for condensed water recovery with small flow and relatively equal pressure in steam-using equipment.

[0018] In summary, for the condensed water in the pipeline, all technical solutions are to return the condensed water to the boiler. Different technical solutions adopt different return methods, and different return methods have different efficiencies in the pressure and temperature recovery of the condensed water. The biggest problem with these solutions is that if there is no condensed water pipeline near the steam transmission pipeline (within about 200m), it is necessary to re-build the condensed water pipeline over a long distance. In this way, the investment in fixed costs will become a huge burden, and the cost cannot be recovered in 10 years.

[0019] Therefore, until today, most energy-consuming units still use direct discharge to deal with condensed water in steam transmission pipelines. How to effectively recycle condensed water in steam pipelines and control the corresponding costs is a technical problem that needs to be solved urgently. Summary of the invention

[0020] The present invention provides a method and system for recovering condensed water from a steam pipeline, aiming to solve the technical problem that the prior art cannot effectively recover condensed water from a steam pipeline and control the corresponding cost.

[0021] One aspect of the present invention relates to a steam pipeline condensate recovery system, which is connected to a drainage pipe on the steam pipeline and includes an introduction mechanism, a collection mechanism, a heating mechanism and a steam exhaust mechanism, wherein:

[0022] An introduction mechanism for introducing condensed water in the drain pipe;

[0023] A collection mechanism connected to the introduction mechanism for collecting the condensed water introduced by the introduction mechanism;

[0024] A heating mechanism disposed near the collection mechanism for heating the condensed water collected by the collection mechanism into steam;

[0025] An exhaust mechanism connected to the collection mechanism for returning the steam heated by the heating mechanism back to the steam pipeline.

[0026] Furthermore, the introduction mechanism includes a water inlet connected to the drain pipe for introducing the condensed water in the drain pipe.

[0027] Furthermore, the collection mechanism includes a condensed water storage tank connected to the water inlet for collecting the condensed water introduced by the water inlet.

[0028] Furthermore, the exhaust mechanism includes an exhaust port respectively connected to the condensed water storage tank and the exhaust pipe for returning the steam heated by the heating mechanism back to the steam pipeline through the exhaust pipe.

[0029] Furthermore, the heating mechanism includes a heater and an electric control box. The heater is electrically connected to the electric control box. The heater is disposed in the condensed water storage tank, and the electric control box is disposed near the outer wall of the condensed water storage tank. The heater is used for heating the condensed water collected by the condensed water storage tank into steam.

[0030] Furthermore, the heating mechanism further includes a water level gauge including a low water level gauge, a middle water level gauge, and a high water level gauge. The low water level gauge, the middle water level gauge, and the high water level gauge are sequentially disposed at the low water level position, the middle water level position, and the high water level position in the condensed water storage tank from low to high; the electric control box is electrically connected to the low water level gauge through a lower water level switch, the electric control box is electrically connected to the middle water level gauge through a middle water level switch, and the electric control box is electrically connected to the high water level gauge through an upper water level switch.

[0031] Furthermore, a sewage discharge pipe is provided at the bottom of the condensed water storage tank. The sewage discharge pipe is connected to the condensed water storage tank, and a sewage discharge valve is provided on the sewage discharge pipe. The sewage discharge valve is electrically connected to the electric control box.

[0032] Furthermore, a drain pipe is provided at the top of the condensed water storage tank. The drain pipe is connected to the condensed water storage tank, and a drain valve is provided on the drain pipe. The drain valve is electrically connected to the electric control box.

[0033] Another aspect of the present invention relates to a method for recovering condensed water in a steam pipeline, which is applied to the above steam pipeline condensed water recovery system and includes the following steps:

[0034] During operation, the condensed water descends from the drain pipe to the condensed water storage tank;

[0035] The steam evaporated from the condensate storage tank rises through the drain pipe to the steam pipeline;

[0036] The steps for the steam evaporated from the condensate storage tank to rise through the drain pipe to the steam pipeline include:

[0037] Detect the high water level gauge. When the condensate reaches the high water level position, open the drain valve for emergency drainage;

[0038] Detect the middle water level gauge. When the condensate reaches the middle water level position, the middle water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated;

[0039] Detect the low water level gauge. When the condensate drops below the low water level position, the low water level switch disconnects, the heater is powered off, and the condensate in the condensate storage tank stops evaporating;

[0040] Start timing from when the heater is turned on. When the set first heating time is reached, directly disconnect the heater regardless of whether the middle water level is closed;

[0041] At the same time, detect whether the low water level gauge is in the closed state. If it is in the closed state, start timing the second heating time from the moment when the heating stops. If the set second heating time is reached, the heater is powered on to continue heating. At the same time, start timing the third heating time.

[0042] Another aspect of the present invention relates to a method for recovering condensate in a steam pipeline, which is applied to the above-mentioned steam pipeline condensate recovery system and includes the following steps:

[0043] During operation, the condensate drops from the drain pipe to the condensate storage tank;

[0044] The steam evaporated from the condensate storage tank rises through the exhaust pipe to the steam pipeline;

[0045] The steps for the steam evaporated from the condensate storage tank to rise through the exhaust pipe to the steam pipeline include:

[0046] Detect the high water level gauge. When the condensate reaches the high water level position, open the drain valve for emergency drainage;

[0047] Detect the middle water level gauge. When the condensate reaches the middle water level position, the middle water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated;

[0048] Detect the low water level gauge. When the condensate drops below the low water level position, the low water level switch disconnects, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0049] The beneficial effects achieved by the present invention are:

[0050] The present invention provides a method and system for recovering condensate from a steam pipeline. The condensate recovery system of the steam pipeline is connected to the drain pipe on the steam pipeline, and includes an introduction mechanism, a collection mechanism, a heating mechanism and an exhaust mechanism. The introduction mechanism is used to introduce the condensate in the drain pipe; the collection mechanism is used to collect the condensate introduced by the introduction mechanism; the heating mechanism is used to heat the condensate collected by the collection mechanism into steam; the exhaust mechanism is used to return the steam heated by the heating mechanism to the steam pipeline. The method and system for recovering condensate from a steam pipeline provided by the present invention install a condensate recovery device on the original condensate drain pipe, and through electric heating, restore the condensate to the steam state, achieving the result that the pipeline no longer discharges condensate outward. The operating cost of the present invention is basically offset by the saved steam cost, and the cost is extremely low; however, it solves the impact of condensate discharge on the safety and environmental protection of the production site, and has great practical value in actual production activities. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic structural diagram of the first embodiment of the condensate recovery system of the steam pipeline of the present invention;

[0052] Figure 2 It is a schematic structural diagram of the second embodiment of the condensate recovery system of the steam pipeline of the present invention;

[0053] Figure 3 It is a schematic structural diagram of the third embodiment of the condensate recovery system of the steam pipeline of the present invention;

[0054] Figure 4 It is a schematic structural diagram of the fourth embodiment of the condensate recovery system of the steam pipeline of the present invention;

[0055] Figure 5 It is a schematic principle diagram of the first embodiment of the condensate recovery system of the steam pipeline of the present invention connected to the steam pipeline;

[0056] Figure 6 It is a schematic principle diagram of the second embodiment of the condensate recovery system of the steam pipeline of the present invention connected to the steam pipeline;

[0057] Figure 7 It is a schematic flow diagram of the first embodiment of the method for recovering condensate from a steam pipeline of the present invention;

[0058] Figure 8 It is a schematic flow diagram of the second embodiment of the method for recovering condensate from a steam pipeline of the present invention.

[0059] Description of the reference numerals in the drawings:

[0060] 10. Inlet; 20. Condensate storage tank; 30. Exhaust port; 31. Exhaust pipe; 41. Heater; 43. Water level gauge; 51. Drain pipe; 52. Drain valve; 61. Drainage pipe; 62. Drainage valve; 100. Steam pipe; 200. Drainage and drainage pipe. Detailed implementation mode

[0061] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the specification drawings and specific implementation modes.

[0062] As Figures 1 to 4 shown, the first embodiment of the present invention proposes a steam pipe condensate recovery system. The steam pipe condensate recovery system is connected to the drainage and drainage pipe 200 on the steam pipe 100, and includes an introduction mechanism, a collection mechanism, a heating mechanism and an exhaust mechanism. Among them, the introduction mechanism is used to introduce the condensate in the drainage and drainage pipe 200; the collection mechanism is connected to the introduction mechanism and is used to collect the condensate introduced by the introduction mechanism; the heating mechanism is arranged near the collection mechanism and is used to heat the condensate collected by the collection mechanism into steam; the exhaust mechanism is connected to the collection mechanism and is used to return the steam heated by the heating mechanism to the steam pipe. In this embodiment, the introduction mechanism, the collection mechanism, the heating mechanism and the exhaust mechanism can adopt existing mechanical or functional equipment, all of which are within the protection scope of this patent.

[0063] Preferably, please see Figures 1 to 6 , for the steam pipe condensate recovery system proposed in this embodiment, the introduction mechanism includes an inlet 10, and the inlet 10 is connected to the drainage and drainage pipe 200 and is used to introduce the condensate in the drainage and drainage pipe.

[0064] Further, referring to Figures 1 to 6 , for the steam pipe condensate recovery system proposed in this embodiment, the collection mechanism includes a condensate storage tank 20, and the condensate storage tank 20 is connected to the inlet 10 and is used to collect the condensate introduced by the inlet 10.

[0065] Further, see in detail Figures 1 to 6 , for the steam pipe condensate recovery system proposed in this embodiment, the exhaust mechanism includes an exhaust port 30, and the exhaust port 30 is respectively connected to the condensate storage tank 20 and the exhaust pipe 31, and is used to return the steam heated by the heating mechanism to the steam pipe through the exhaust pipe 31.

[0066] Preferably, please see Figures 1 to 6, the condensate recovery system for steam pipelines proposed in this embodiment. The heating mechanism includes a heater 41 and an electric control box. The heater 41 is electrically connected to the electric control box. The heater 41 is arranged inside the condensate storage tank 20, and the electric control box is arranged close to the outer wall of the condensate storage tank 20. The heater 41 is used to heat the condensate collected in the condensate storage tank 20 into steam. Specifically, the heating mechanism further includes a water level gauge 43. The water level gauge 43 includes a low water level gauge, a medium water level gauge, and a high water level gauge. The low water level gauge, the medium water level gauge, and the high water level gauge are successively arranged at the low water level position, the medium water level position, and the high water level position inside the condensate storage tank 20 from low to high; the electric control box is electrically connected to the low water level gauge through a lower water level switch, the electric control box is electrically connected to the medium water level gauge through a medium water level switch, and the electric control box is electrically connected to the high water level gauge through an upper water level switch. A drain pipe 51 is arranged at the bottom of the condensate storage tank 20. The drain pipe 51 is connected to the condensate storage tank 20, and a drain valve 52 is arranged on the drain pipe 51. The drain valve 52 is electrically connected to the electric control box. A drain pipe 61 is arranged at the top of the condensate storage tank 20. The drain pipe 61 is connected to the condensate storage tank 20, and a drain valve 62 is arranged on the drain pipe 61. The drain valve 62 is electrically connected to the electric control box. For the condensate recovery system for steam pipelines proposed in this embodiment, by detecting the high water level gauge, when the electric control box recognizes that the condensate detected by the high water level gauge reaches the high water level position, the drain valve is opened for emergency drainage; by detecting the medium water level gauge, when the electric control box recognizes that the condensate detected by the medium water level gauge reaches the medium water level position, the medium water level switch is controlled to close, and the heater is powered on, and the condensate in the condensate storage tank starts to heat and evaporate; by detecting the low water level gauge, when the electric control box recognizes that the condensate detected by the low water level gauge drops below the lower water level position, the lower water level switch is controlled to disconnect, and the heater is powered off, and the condensate in the condensate storage tank no longer evaporates; and start timing from when the heater is powered on. When the set first heating time (e.g., 5400 / m s ) is reached, the heater is directly disconnected regardless of whether the medium water level is closed; at the same time, it is detected whether the lower water level gauge is in a closed state. If it is in a closed state, the second heating time is timed from the moment when the heating stops. If the set second heating time (150 s) is reached, the heater is powered on to continue heating, and at the same time, the third heating time is started.

[0067] The first embodiment of the present invention relates to a method for recovering condensate from steam pipelines, which is applied to the above-mentioned condensate recovery system for steam pipelines. When the electric control box recognizes that the flow rate of the condensate in the hydrophobic pipeline is lower than the preset speed threshold (1.2 m / s), the following method for recovering condensate from steam pipelines is adopted. The method for recovering condensate from steam pipelines includes the following steps:

[0068] Step S110: During operation, the condensate drops from the drain pipe to the condensate storage tank.

[0069] Step S120: The steam evaporated from the condensate storage tank rises through the drain pipe to the steam pipe.

[0070] Step S120 includes:

[0071] Step S121: Detect the high water level gauge. When the condensate reaches the high water level position, open the drain valve for emergency drainage.

[0072] By detecting the high water level gauge, when the electric control box recognizes that the condensate detected by the high water level gauge reaches the high water level position, open the drain valve for emergency drainage.

[0073] Step S122: Detect the middle water level gauge. When the condensate reaches the middle water level position, the middle water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated.

[0074] By detecting the middle water level gauge, when the electric control box recognizes that the condensate detected by the middle water level gauge reaches the middle water level position, control the middle water level switch to close, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated.

[0075] Step S123: Detect the low water level gauge. When the condensate drops below the lower water level position, the lower water level switch disconnects, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0076] By detecting the low water level gauge, when the electric control box recognizes that the condensate detected by the low water level gauge drops below the lower water level position, control the lower water level switch to disconnect, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0077] Step S124: Start timing from when the heater is powered on. When the set first heating time is reached, directly disconnect the heater regardless of whether the middle water level is closed or not.

[0078] The electric control box controls the operation of the heater. Start timing from when the heater is powered on. When the set first heating time (e.g., 5400 / m s ) is reached, directly disconnect the heater regardless of whether the middle water level is closed or not.

[0079] Step S125: At the same time, detect whether the lower water level gauge is in the closed state. If it is in the closed state, start timing the second heating time from the moment when the heating stops. If the set second heating time is reached, the heater is powered on to continue heating. At the same time, start timing the third heating time.

[0080] The electronic control box checks whether the lower water level gauge is in a closed state. If it is in a closed state, the second heating time starts counting from the moment when heating stops. After reaching the set second heating time (150 s), the heater is powered on to continue heating. At the same time, the third heating time starts counting.

[0081] The second embodiment of the present invention relates to a method for recovering condensate from a steam pipeline, which is applied to the above-mentioned steam pipeline condensate recovery system. When the electronic control box recognizes that the flow rate of condensate in the drain pipeline is higher than the preset speed threshold (1.2 m / s), the following steps are included in this steam pipeline condensate recovery method:

[0082] Step S210: During operation, the condensate descends from the drain pipe to the condensate storage tank.

[0083] Step S220: The steam evaporated from the condensate storage tank rises to the steam pipeline through the exhaust pipe.

[0084] Step S220 includes:

[0085] Step S221: Check the high water level gauge. When the condensate reaches the high water level position, open the drain valve for emergency drainage.

[0086] By checking the high water level gauge, when the electronic control box recognizes that the condensate detected by the high water level gauge reaches the high water level position, open the drain valve for emergency drainage.

[0087] Step S222: Check the middle water level gauge. When the condensate reaches the middle water level position, the middle water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to heat and evaporate.

[0088] By checking the middle water level gauge, when the electronic control box recognizes that the condensate detected by the middle water level gauge reaches the middle water level position, control the middle water level switch to close, the heater is powered on, and the condensate in the condensate storage tank starts to heat and evaporate.

[0089] Step S223: Check the low water level gauge. When the condensate drops below the lower water level position, the lower water level switch disconnects, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0090] By checking the low water level gauge, when the electronic control box recognizes that the condensate detected by the low water level gauge drops below the lower water level position, control the lower water level switch to disconnect, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0091] As Figures 1 to 8 shown, the working principle of the steam pipeline condensate recovery method and system provided in this embodiment is as follows:

[0092] The technical solution provided by this embodiment is to directly collect the condensed water in the pipeline, and then directly adopt the electric heating method. After heating, the condensed water returns to the steam state and then returns to the steam pipeline for continued use. This technical solution can avoid the high investment in the construction cost of the condensate (along with the steam transmission pipeline). At the same time, it can recover energy more effectively.

[0093] It is further noted that according to the standard DL / T5054-2016 "Code for Design of Steam and Water Pipelines in Thermal Power Plants", for the drain pipe diameter of low-temperature and low-pressure steam on the steam pipeline, it shall not be less than 38mm. In actual engineering design, the distance between the drain pipes of long-distance steam pipelines shall not exceed 50m. That is to say, there are already drain pipes on the original steam pipeline. Our technology is to directly install a steam condensate recovery device on the original drain pipe to achieve the result of no longer discharging condensate externally.

[0094] The steam pipeline condensate recovery system consists of a water inlet 10, an exhaust port 30, a condensate storage tank 20, a heater 41, an electric control box, a water level gauge 43, and a blowdown valve 52. The heater 41 is responsible for providing the heat required for heating. The water inlet 10 introduces the condensate from the steam pipeline into the condensate storage tank, and after heating, it becomes steam and returns to the steam pipeline 100 from the exhaust port 30. The condensate storage tank 20 is equipped with 3 water level gauges, namely a low water level gauge, a medium water level gauge, and a high water level gauge. The water level gauge is a sensor that controls when to start heating and when to stop heating. When the low water level position is reached, heating starts; when the medium water level position is reached, heating stops; when the high water level position is reached, the blowdown valve is opened to discharge excessive condensate to ensure the safety of the steam pipeline. The electric control box among them is an integrated and protection device for electrical equipment.

[0095] There are 2 methods for the steam pipeline condensate recovery device system to be connected to the original system. When the flow rate of the condensate in the drain pipeline is lower than 1.2m / s, Method 1 can be adopted. When it is greater than 1.2m / s, Method 2 can be adopted. The specific connection methods are as Figure 5 and Figure 6 shown:

[0096] Method 1 for connecting to the original system:

[0097] Explanation: The exhaust and the water inlet are the same pipeline, and whether the pipeline is in the heating or exhaust state is determined by whether the heater is heating.

[0098] Method 2 for connecting to the original system:

[0099] Explanation: The exhaust and the water inlet are two different pipelines, which are respectively responsible for exhaust and the entry of condensate.

[0100] I. Heating power calculation method

[0101] For different pipelines, recovery devices with different powers should be used. It is necessary to accurately master the condensate volume of the condensate recovery system. The formula for calculating the condensate water in the steam pipeline is

[0102]

[0103] where, m s is the condensate water volume (unit: kg / h), Q is the radiative heat transfer obtained by looking up the table (unit: W / m), L is the equivalent length of the pipeline including flanges and joints (unit: m), f is the heat insulation coefficient obtained by looking up the table, and h fg is the evaporation enthalpy of steam under the pipeline pressure (unit: kJ / kg).

[0104] II. The formula for calculating the heat dissipation power (heating power) is:

[0105] HS = Q * L * f

[0106] where, HS is the heat dissipation power (unit: kW).

[0107] Example:

[0108] Suppose the steam in the pipeline is steam at 188 °C and 1.2 MPa. The latent heat of vaporization of this steam is 1985.7 kJ / kg, the pipeline length is 100 m, the pipeline diameter is DN100, and the thickness of the insulation layer is 50 mm. The ambient temperature is 20 °C.

[0109] III. Calculate the condensate water volume

[0110] 1) Calculate the temperature difference

[0111] 188 - 20 = 168 °C

[0112] 2) Through the temperature difference and pipeline diameter, look up the steel pipe radiation heat dissipation table, Q = 1200 W / m.

[0113] 3) Suppose the air flow rate is 0.

[0114] 4) Through the thickness of the insulation layer and steam pressure, look up the heat insulation coefficient table, f = 0.08.

[0115] 5) Calculate the heat dissipation as:

[0116] HS = 1200 * 100 * 0.08

[0117] = 9600 W = 9.6 kW

[0118] 6) Calculate the condensate water volume

[0119]

[0120] Radiation heat dissipation table of uninsulated steel pipe exposed to air at 20 °C

[0121]

[0122] Influence of air flow in the environment on radiative heat dissipation from the pipeline surface

[0123] Air flow rate m / s Heat dissipation factor 0.00 1.0 0.50 1.0 1.00 1.3 2.00 1.7 2.50 1.8 3.00 2.0 4.00 2.3 6.00 2.9 8.00 3.5 10.00 4

[0124] Heat preservation coefficient

[0125]

[0126]

[0127] Operation method 1:

[0128] During operation, the condensate descends from the drain pipe to the condensate storage tank, and the steam evaporated from the condensate storage tank rises through the drain pipe to the steam pipeline. Therefore, the drain pipe undertakes both the downward flow of the condensate and the upward flow of the steam.

[0129] However, this situation cannot occur simultaneously, that is, it cannot be in the state of both upward and downward flow at the same time, and can only be carried out in time segments.

[0130] In the automatic control design, it is designed to carry out heating and stop heating (venting) in time segments. During the heating and evaporation process, the drain pipe functions as the upward flow of the steam, and at this time, the condensate generated in the steam pipeline cannot come down temporarily and accumulates in the steam pipeline. After the heating period passes, the drain pipe functions as the downward flow of the condensate. The condensate in the steam pipeline is drained downward into the condensate storage tank.

[0131] In this way, in the continuous cycle of heating - pausing - heating - pausing, the purpose of continuously evaporating the condensate in the steam pipeline is achieved.

[0132] Automatic control logic:

[0133] Based on the detection of the states of low, medium, and high water levels (liquid level lower than disconnect, liquid level lower than close), determine the on / off of the heater.

[0134] The specific judgment logic is as follows:

[0135] 1) Detect the high water level gauge. When the condensate reaches this position, open the drain valve for emergency drainage.

[0136] 2) Detect the medium water level gauge. When the condensate reaches this position, the medium water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated.

[0137] During the heating and evaporation process, the steam in the condensate storage tank rises through the drain pipe into the steam pipeline, and the water level in the condensate storage tank drops after the condensate evaporates.

[0138] 3) Detect the water level gauge. When the condensate level drops below the lower water level, the lower water level switch disconnects, the heater cuts off the power supply, and the condensate in the condensate storage tank stops evaporating.

[0139] At this time, since the condensate continuously generated in the steam delivery pipeline still descends into the condensate storage tank through the drain pipe, the water level in the condensate storage tank is continuously rising.

[0140] 4) Start timing from when the heater is turned on. When the time s is reached, regardless of whether the middle water level is closed or not, the heater will be directly disconnected.

[0141] Calculation method of the heating time s:

[0142] 1. Calculation of the condensate volume

[0143]

[0144] 2. Calculate the heating time

[0145] s = 5400 / m s

[0146] s is the heating time (unit: s), m s is the condensate volume (unit: kg / h).

[0147] 5) After stopping heating through the above heating time, simultaneously detect whether the lower water level gauge is in a closed state. If it is in a closed state, start timing from the moment when heating stops, and the pause heating time is 150 s. After reaching the pause heating time, the heater is turned on to continue heating. At the same time, start timing when the heater is turned on.

[0148] Operation method 2:

[0149] During operation, the condensate descends from the drain pipe into the condensate storage tank, and the steam evaporated from the condensate storage tank rises through the exhaust pipe into the steam pipeline.

[0150] In automatic control, the heater is controlled by the water level gauge.

[0151] Automatic control logic:

[0152] Based on the detection of the states (liquid level below disconnection, liquid level below closure) of the low, middle, and high water levels, determine the on / off of the heater.

[0153] The specific judgment logic is as follows:

[0154] 1) Detect the high water level gauge. When the condensate reaches this position, open the drain valve for emergency drainage.

[0155] 2) Detect the middle water level gauge. When the condensate reaches this position, the middle water level switch closes, the heater is powered on, and the condensate in the condensate storage tank starts to be heated and evaporated.

[0156] 3) Detect the middle water level gauge. When the condensate drops below the lower water level, the lower water level switch disconnects, the heater is powered off, and the condensate in the condensate storage tank stops evaporating.

[0157] At this time, since condensate continues to be generated in the steam delivery pipeline and still descends into the condensate storage tank through the hydrophobic pipeline, the water level in the condensate storage tank is constantly rising.

[0158] Example:

[0159] Continuing with the above case, assume the steam price is 180 yuan / t, 0.18 yuan / kg, and the electricity cost is 0.5 yuan / kW·h. The amount of condensate formed is 17.4 kg / h. In actual use, since the discharge of condensate is driven by steam, there will inevitably be steam discharged along with it. In the above example, the measured steam discharge per hour is 7.8 kg / h.

[0160] 1) Calculate the cost savings of steam

[0161] (7.8 + 17.4) * 0.18 = 4.536 yuan / h

[0162] 2) Calculate the electricity consumption cost

[0163] As calculated in the previous case, the power consumption is 9.6 kW, so the actual electricity cost is

[0164] 9.6 * 0.5 = 4.8 yuan / h

[0165] 3) The actual cost is 0.26 yuan / h.

[0166] Conclusion:

[0167] The operating cost is basically offset by the cost savings of steam, and the cost is extremely low. However, this equipment solves the impact of condensate discharge on the safety and environmental protection of the production site and has great practical value in actual production activities.

[0168] This embodiment provides a method and system for recovering condensate from steam pipelines. Compared with the prior art, the condensate recovery system for steam pipelines is connected to the drain pipe on the steam pipeline, and includes an introduction mechanism, a collection mechanism, a heating mechanism, and an exhaust mechanism. The introduction mechanism is used to introduce the condensate in the drain pipe; the collection mechanism is used to collect the condensate introduced by the introduction mechanism; the heating mechanism is used to heat the condensate collected by the collection mechanism into steam; the exhaust mechanism is used to return the steam heated by the heating mechanism to the steam pipeline. The method and system for recovering condensate from steam pipelines provided by this embodiment install a condensate recovery device on the original condensate drain pipe, and through electric heating, restore the condensate to the steam state, achieving the result that the pipeline no longer discharges condensate outward. The operating cost of this embodiment is basically offset by the saved steam cost, and the cost is extremely low; however, it solves the impact of condensate discharge on the safety and environmental protection of the production site, and has great practical value in actual production activities.

[0169] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A steam pipeline condensate recovery system, characterized in that: The steam pipeline condensate recovery system is connected to the drainage pipe on the steam pipeline, and includes an introduction mechanism, a collection mechanism, a heating mechanism and a steam exhaust mechanism, wherein: The introduction mechanism is used to introduce condensed water in the drainage pipe; The collecting mechanism is connected to the introducing mechanism and is used to collect the condensed water introduced by the introducing mechanism; The heating mechanism is arranged close to the collecting mechanism and is used to heat the condensed water collected by the collecting mechanism into steam; The steam exhaust mechanism is connected to the collecting mechanism and is used to return the steam heated by the heating mechanism to the steam pipeline.

2. The steam pipeline condensate recovery system according to claim 1, characterized in that: The introduction mechanism comprises a water inlet (10), which is connected to the drainage pipe and is used to introduce condensed water in the drainage pipe.

3. The steam pipeline condensate recovery system according to claim 2, characterized in that: The collecting mechanism comprises a condensed water storage tank (20), which is connected to the water inlet (10) and is used to collect condensed water introduced by the water inlet (10).

4. The steam pipeline condensate recovery system according to claim 3, characterized in that: The steam exhaust mechanism comprises a steam exhaust port (30), which is respectively connected to the condensate storage tank (20) and the steam exhaust pipe (31) and is used to return the steam heated by the heating mechanism to the steam pipeline through the steam exhaust pipe (31).

5. The steam pipeline condensate recovery system according to claim 4, characterized in that: The heating mechanism comprises a heater (41) and an electrical control box, wherein the heater (41) is electrically connected to the electrical control box, the heater (41) is arranged in the condensed water storage tank (20), and the electrical control box is arranged close to the outer wall of the condensed water storage tank (20), and the heater (41) is used to heat the condensed water collected in the condensed water storage tank (20) into steam.

6. The steam pipeline condensate recovery system according to claim 5, characterized in that: The heating mechanism also includes a water level gauge (43), the water level gauge (43) including a low water level gauge, a middle water level gauge and a high water level gauge, the low water level gauge, the middle water level gauge and the high water level gauge being arranged in sequence from low to high at a low water level position, a middle water level position and a high water level position in the condensate storage tank (20); the electric control box is electrically connected to the low water level gauge via a lower water level switch, the electric control box is electrically connected to the middle water level gauge via a middle water level switch, and the electric control box is electrically connected to the high water level gauge via an upper water level switch.

7. The steam pipeline condensate recovery system according to claim 6, characterized in that: A drain pipe (51) is provided at the bottom of the condensed water storage tank (20), and the drain pipe (51) is connected to the condensed water storage tank (20). A drain valve (52) is provided on the drain pipe (51), and the drain valve (52) is electrically connected to the electrical control box.

8. The steam pipeline condensate recovery system according to claim 6, characterized in that: A drain pipe (61) is provided on the top of the condensate storage tank (20), and the drain pipe (61) is connected to the condensate storage tank (20). A drain valve (62) is provided on the drain pipe (61), and the drain valve (62) is electrically connected to the electrical control box.

9. A method for recovering condensed water from a steam pipeline, characterized in that: Applicable to the steam pipeline condensate recovery system according to any one of claims 1 to 8, comprising the following steps: During operation, condensate water drops from the drain pipe to the condensate storage tank; The steam evaporated from the condensate storage tank rises to the steam pipe through the drain pipe; The step of steam evaporated from the condensate storage tank rising to the steam pipeline through the drainage pipe comprises: Check the high water level gauge. When the condensed water reaches the high water level, open the drain valve for emergency drainage. Detect the middle water level gauge. When the condensed water reaches the middle water level, the middle water level switch is closed, the heater is powered on, and the condensed water in the condensed water storage tank begins to heat and evaporate. Detect the low water level gauge. When the condensed water drops below the lower water level, the lower water level switch is disconnected, the heater is disconnected from the power supply, and the condensed water in the condensed water storage tank no longer evaporates; The timing starts from when the heater is turned on. When the set first heating time is reached, the heater is directly disconnected regardless of whether the water level is closed. At the same time, check whether the water level gauge is in a closed state. If it is in a closed state, the second heating time will be counted from the moment the heating stops. If the set second heating time is reached, the heater will be powered on to continue heating. At the same time, the third heating time will be counted.

10. A method for recovering condensed water from a steam pipeline, characterized in that: Applicable to the steam pipeline condensate recovery system according to any one of claims 1 to 8, comprising the following steps: During operation, condensate drops from the drain pipe to the condensate storage tank; The steam evaporated from the condensate storage tank rises to the steam pipe through the exhaust pipe; The step of steam evaporated from the condensate storage tank rising to the steam pipeline through the exhaust pipe comprises: Check the high water level gauge. When the condensed water reaches the high water level, open the drain valve for emergency drainage. Detect the middle water level gauge. When the condensed water reaches the middle water level, the middle water level switch is closed, the heater is powered on, and the condensed water in the condensed water storage tank begins to heat and evaporate. Detect the low water level gauge. When the condensed water drops below the lower water level position, the lower water level switch is disconnected, the heater is disconnected from the power supply, and the condensed water in the condensed water storage tank no longer evaporates.

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