Zero-power-consumption system for recycling and treating condensed water

Abstract

The invention relates to the technical field of condensed water recovery, in particular to a zero-power-consumption condensed water recovery treatment system which comprises a demineralized water plate heat exchanger, an automatic control pressure reducing valve, an oil and iron removal system and a demineralized water station mixed bed. A water outlet of the demineralized water plate heat exchanger is connected with a water inlet of the oil and iron removal system through an automatic control pressure reducing valve; and a water outlet of the oil and iron removal system is connected with a water inlet of the desalted water station mixed bed. By optimizing the pressure regulation and control logic and the flow path of the condensation water station, efficient connection of'pressure regulation-treatment 'of condensation water can be achieved, the treatment flow can be effectively simplified, power consumption can be eliminated, and condensate pressure can be recycled.

Description

Technical Field

[0001] This invention relates to the field of condensate recovery technology, and more particularly to a zero-power-consumption condensate recovery and treatment system. Background Technology

[0002] In the process of steam utilization in the chemical industry, the recovery and treatment of steam condensate is the core link to achieve energy conservation, consumption reduction and water resource recycling. As the core hub of condensate recovery and treatment, the rationality of the process of the condensate station directly affects the overall benefits.

[0003] Currently, the mainstream steam condensate recovery process in condensate stations is as follows: Low-pressure steam condensate (130-150℃, 0.9-1.1MPa, typically 1.0MPa) generated by the production unit is transported to the condensate station. It first undergoes heat exchange through a demineralized water plate heat exchanger to lower the condensate temperature to the required level. Then, an automatic pressure-reducing valve maintains the upstream pressure at approximately 1.0MPa. The condensate, whose pressure is not utilized, is directly discharged into a condensate tank for buffering. To meet the pressure requirements of subsequent processing steps, an additional condensate pump is needed to pressurize the condensate to 0.5-0.7MPa (typically 0.6MPa), before sending it to an oil and iron removal system consisting of a precision filter and an oil-free tank. After treatment, the condensate pressure drops to 0.3-0.5MPa (typically 0.4MPa) and is finally transported to the mixed bed of the demineralized water station for further treatment.

[0004] The traditional processes used in the aforementioned condensate stations have significant technical drawbacks: First, high equipment redundancy, requiring additional investment in condensate tanks, condensate pumps, and other equipment, which not only increases the initial procurement cost of the condensate station but also occupies a large amount of space within the station; second, serious energy waste, as the condensate pumps continuously consume electricity to operate, and the condensate pressure regulated by the pressure reducing valve is not recovered and utilized, resulting in pressure energy loss; third, high operation and maintenance costs, as the large number of devices leads to complex maintenance procedures for the condensate station, making it prone to failure points and affecting the stable operation of the system. Therefore, how to simplify the processing flow of the condensate station, eliminate power consumption, and recover and utilize condensate pressure through process optimization has become a key issue that urgently needs to be addressed in the field of chemical steam condensate recovery. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a zero-power-consumption condensate recovery and treatment system. By optimizing the pressure control logic and process path of the condensate station, the system achieves efficient connection between condensate pressure regulation and treatment.

[0006] The technical solution adopted in this invention is as follows: The present invention proposes a zero-power-consumption condensate recovery and treatment system, comprising a demineralized water plate heat exchanger, an automatic control pressure reducing valve, an oil and iron removal system, and a mixed bed in the demineralized water station; the outlet of the demineralized water plate heat exchanger is connected to the inlet of the oil and iron removal system through the automatic control pressure reducing valve; the outlet of the oil and iron removal system is connected to the inlet of the mixed bed in the demineralized water station.

[0007] Furthermore, the demineralized water plate heat exchanger is used to cool the steam condensate entering the condensate station. The condensate temperature after heat exchange by the demineralized water plate heat exchanger is 45-55℃, and the initial pressure is 0.9-1.1MPa.

[0008] Furthermore, the condensate temperature after heat exchange via the demineralized water plate is preferably 50°C, and the initial pressure is preferably 1.0 MPa.

[0009] Furthermore, the preset pressure regulation value of the automatic control pressure reducing valve is 0.5-0.7 MPa.

[0010] Furthermore, the outlet pressure of the automatic control pressure reducing valve is preferably 0.6 MPa.

[0011] Furthermore, the oil and iron removal system consists of a precision filter and an oil-free tank. After the condensate is regulated by an automatic pressure reducing valve, it flows through the precision filter and the oil-free tank in sequence, and the pressure drops to 0.3-0.5 MPa before directly entering the mixed bed of the demineralized water station.

[0012] Compared with the prior art, the present invention has the following beneficial effects: This invention, through its core improvement of "eliminating redundant equipment and recovering condensate pressure," generates significant technical, economic, and operational benefits for a condensate treatment scale of 1000 tons / hour, as detailed below: 1. Achieve zero-power operation: Eliminate the condensate pump (approximately 250kW per unit) required for a 1000-ton / hour flow rate in the traditional process, completely eliminating power consumption in the condensate transportation process. Based on 8000 hours of operation per year and an industrial electricity price of 0.6 yuan / kWh, the annual electricity cost savings are: 250kW × 8000h × 0.6 yuan / kWh = 1.2 million yuan. The energy-saving benefits are directly achieved through the core improvement of "using the condensate's own pressure to replace the pump drive."

[0013] 2. Streamlined equipment investment, significantly reducing initial costs: Eliminating the need for brine tanks (1000-ton class, costing approximately 300,000 yuan), high-power condensate pumps (costing approximately 200,000 yuan per unit), and supporting equipment such as pipelines, control valves, and electrical control cabinets, a single system can reduce initial equipment procurement and installation investment by 600,000 to 800,000 yuan. The cost advantage stems from the design optimization of "simplifying the core components of the system".

[0014] 3. Reduce maintenance steps and lower long-term operating costs: By eliminating equipment such as condensate tanks and condensate pumps, the number of system failure points is reduced by more than 40%, saving 80,000 to 100,000 yuan annually in equipment maintenance labor and spare parts replacement costs (such as water pump bearings, seals, and maintenance of anti-corrosion coatings inside the tank); at the same time, it reduces the amount of manual operation for equipment start-up, shutdown, and inspection, improving maintenance efficiency.

[0015] 4. Optimize process flow and improve operational stability: Eliminate the intermediate link of "pressure reducing valve → condensate tank → condensate pump". Condensate is directly regulated by the pressure reducing valve before entering the oil and iron removal system. This avoids pressure instability caused by pump start-up and shutdown and fluctuations in tank liquid level. It ensures that the feed pressure of the oil and iron removal system is stable at around 0.6MPa under a large flow rate of 1000 tons / hour, and the consistency of treatment effect is significantly improved.

[0016] 5. Saves site space and adapts to project layout requirements: A 1000-ton condensate tank occupies approximately 80 square meters of space. 2 The supporting water pump and auxiliary equipment occupy an area of ​​approximately 20m². 2 This invention can directly save 100m² of station space. 2 The above is particularly applicable to site planning for new condensate stations in large chemical industrial parks, or to space-constrained scenarios during the renovation of old stations, thereby improving the flexibility of project layout. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a zero-power-consumption condensate recovery and treatment system proposed in this invention.

[0018] In the attached diagram, the following labels are used: 1-Demineralized water heat exchanger; 2-Automatic control pressure reducing valve; 3-Oil and iron removal system; 31-Precision filter; 32-Oil-free tank; 4-Demineralized water station mixed bed; 5-Seawater heat exchanger; 6-Regulating valve. Detailed Implementation

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0021] See appendix Figure 1 This invention proposes a zero-power-consumption condensate recovery and treatment system, comprising a demineralized water heat exchanger 1, an automatic control pressure reducing valve 2, an oil and iron removal system 3, a demineralized water station mixed bed 4, and a seawater heat exchanger 5. The outlet of the demineralized water heat exchanger 1 is connected to the inlet of the seawater heat exchanger 5, and the outlet of the seawater heat exchanger 5 is connected to the inlet of the oil and iron removal system 3 via the automatic control pressure reducing valve 2. The outlet of the oil and iron removal system 3 is connected to the inlet of the demineralized water station mixed bed 4. The automatic control pressure reducing valve 2 connects the demineralized water heat exchanger 1, the seawater heat exchanger 5, and the oil and iron removal system 3, and is used to precisely regulate the condensate pressure. The oil and iron removal system 3 is used to perform precision filtration and oil removal treatment on the condensate after pressure regulation. The demineralized water station mixed bed 4 is used to receive the condensate after oil and iron removal treatment and perform deep purification.

[0022] The inlet and outlet of the demineralized water plate heat exchanger 1 are respectively equipped with control valves; the inlet and outlet of the seawater plate heat exchanger 5 are respectively equipped with control valves, and a regulating valve 6 is connected in parallel on one side of the seawater plate heat exchanger 5; the seawater plate heat exchanger 5 serves as a backup means, and if the cooling effect of the demineralized water plate heat exchanger 1 is not ideal, heat can be exchanged again through the seawater plate heat exchanger 5.

[0023] The oil and iron removal system 3 consists of a precision filter 31 and an oil-free tank 32 connected in series. Both the inlet and outlet of the precision filter 31 and the oil-free tank 32 are equipped with control valves. After being regulated by the automatic pressure reducing valve 2, the condensate flows through the precision filter 31 and the oil-free tank 32, and the pressure drops to 0.3-0.5 MPa before directly entering the mixed bed 4 of the demineralized water station. The inlet of the mixed bed 4 of the demineralized water station is equipped with a control valve.

[0024] The demineralized water plate heat exchanger 1 is used to exchange heat and cool the steam condensate entering the condensate station. The temperature of the condensate after heat exchange by the demineralized water plate heat exchanger 1 is 45-55℃, preferably 50℃. This temperature can prevent the filter media in the oil and iron removal system 3 from aging due to excessive temperature of the condensate, while taking into account the heat exchange efficiency and the process compatibility of subsequent treatment. The initial pressure of the condensate after heat exchange by the demineralized water plate heat exchanger 1 is 0.9-1.1MPa, preferably 1.0MPa. This pressure can match the conventional output pressure of low-pressure steam condensate in chemical plants, and can be directly introduced into the system without additional pretreatment, thus improving applicability.

[0025] The preset pressure regulation value of the automatic control pressure reducing valve is 0.5-0.7MPa, and the outlet pressure is preferably 0.6MPa. This pressure can meet the feed pressure requirements of the oil and iron removal system 3 (to ensure filtration rate and oil removal efficiency), and also allow the condensate to naturally drop to 0.4MPa after treatment, accurately matching the feed pressure requirements of the mixed bed 4 of the demineralized water station, without the need for secondary pressure adjustment.

[0026] The working process of this invention is as follows: Raw material input: The low-pressure steam condensate at 130-150℃ and 0.9-1.1MPa (preferably 1.0MPa) generated by the chemical plant production unit is transported to the condensate station; Heat exchange and cooling: The condensate enters the demineralized water plate heat exchanger 1 and exchanges heat with the demineralized water to cool down to 45-55℃ (preferably 50℃). After heat exchange, the condensate pressure is still maintained at 0.9-1.1MPa (preferably 1.0MPa). Pressure regulation: The condensate after heat exchange enters the automatic control pressure reducing valve 2, which precisely regulates the pressure from 0.9-1.1MPa (preferably 1.0MPa) to 0.5-0.7MPa (preferably 0.6MPa). Oil and iron removal treatment: The condensate, adjusted to 0.5-0.7MPa (preferably 0.6MPa), enters the oil and iron removal system 3 directly by its own pressure, and flows through the precision filter and the oil-free tank in sequence to complete the removal of impurities and oil. Deep treatment: After oil and iron removal, the condensate pressure naturally drops to 0.3-0.5MPa (preferably 0.4MPa), and is directly transported to the mixed bed 4 of the demineralized water station for deep purification and recycling.

[0027] The specific differences between this invention and the prior art are as follows:

[0028] The improvements of this invention compared to the prior art are as follows: The function of the automatic control pressure reducing valve 2 is improved: it is optimized from "only maintaining the front end pressure" to "precisely setting the outlet pressure to 0.5-0.7MPa", giving it a dual function of "pressure regulation + power supply"; Process path improvement: Eliminate the two redundant steps of "condensate tank buffer" and "condensate pump pressurization" to build a short process of "pressure reducing valve direct drive oil and iron removal system"; System composition improvements: The condensate tank and condensate pump have been removed, simplifying the system structure.

[0029] The following experiment uses the 1000-ton / hour condensate recovery station of Hengli Petrochemical (Dalian) New Material Technology Co., Ltd. as a case study. Through a 30-day comparative experiment between the traditional process and the process of this invention, the effectiveness of the technology is verified. The experiment only focuses on the in-station treatment process, and the core equipment parameters are the same.

[0030] I. Basic Experimental Conditions 1. Target of treatment: Steam condensate (processing capacity 1000 tons / hour), water quality: TOC < 15 mg / L, suspended solids < 2 mg / L, iron < 0.3 mg / L, conductivity < 10 μS / cm.

[0031] 2. Core equipment: Demineralized water plate heat exchanger: 1000 tons / hour on the condensate side, 300 tons / hour on the demineralized water side; Precision filters: 2 units (600 tons / hour each, one in use and one on standby); Oil tankers prohibited: 8 units (150 tons / hour per unit).

[0032] II. Comparison of Experimental Data (a) Traditional process (control group)

[0033] (II) The process of this invention (experimental group, pressure reducing valve outlet pressure 0.6MPa)

[0034] III. Verification of Other Parameters (Process of this Invention) 1. Pressure reducing valve outlet pressure of 0.5MPa: pressure fluctuation ±2.0%, water quality meets standards, and electricity costs are 95,040 yuan lower than traditional processes under the same conditions.

[0035] 2. Pressure reducing valve outlet pressure of 0.7MPa: pressure fluctuation ±1.4%, better water quality, no damage to filter media, and electricity savings of 120,960 yuan.

[0036] IV. Experimental Conclusions This invention achieves zero-power delivery by eliminating the condensate tank and water pump and optimizing the pressure of the pressure reducing valve. This can save more than 1.2 million yuan in electricity costs per year, reduce investment by 850,000 yuan, improve pressure stability, and produce better quality water. The pressure range of 0.5-0.7MPa is suitable for process requirements.

[0037] Matters not covered in this invention are common knowledge.

[0038] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A zero electricity consumption system for condensate recovery treatment, characterized by: The system comprises a desalted water plate exchanger, an automatic control pressure reducing valve, an oil and iron removing system and a mixed bed of a desalted water station; the water outlet of the desalted water plate exchanger is connected with the water inlet of the oil and iron removing system through the automatic control pressure reducing valve; the water outlet of the oil and iron removing system is connected with the water inlet of the mixed bed of the desalted water station.

2. The zero electricity consumption system for condensate recovery treatment according to claim 1, characterized in that: The desalted water plate exchanger is used for heat exchange and temperature reduction of steam condensate entering the condensate water station, and the condensate water after heat exchange of the desalted water plate exchanger has a temperature of 45-55℃ and an initial pressure of 0.9-1.1MPa.

3. A zero electricity consumption system for condensate recovery treatment according to claim 2, characterized in that: The condensate water after heat exchange of the desalted water plate exchanger has a temperature of 50℃ and an initial pressure of 1.0MPa.

4. The zero electricity consumption system for condensate recovery treatment according to claim 1, characterized in that: The preset pressure regulating value of the automatic control pressure reducing valve is 0.5-0.7MPa.

5. The zero electricity consumption system for condensate recovery treatment according to claim 1, characterized in that: The outlet pressure of the automatic control pressure reducing valve is preferably 0.6MPa.

6. The zero electricity consumption system for condensate recovery treatment according to claim 1, characterized in that: The oil and iron removing system is composed of a precision filter and an oil tank, and the condensate water after regulation of the automatic control pressure reducing valve flows through the precision filter and the oil tank in sequence, and then the pressure is reduced to 0.3-0.5MPa and directly enters the mixed bed of the desalted water station.

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