Condensate water waste heat recovery and deaerator heat optimized utilization system

Abstract

A condensate waste heat recovery and deaerator heat optimization system belongs to the field of waste heat recovery and utilization technology. This invention solves the problems of low heat exchange efficiency and insufficient recovery of condensate waste heat in existing condensate waste heat recovery systems. Condensate is connected to the hot-side inlet of the heat exchange unit through the condensate delivery pipeline, and demineralized water is connected to the cold-side inlet of the heat exchange unit through the demineralized water supply pipeline. The demineralized water, heated by heat exchange, flows through the cold-side outlet of the heat exchange unit to the heated demineralized water main pipeline. A water supply crossover line connects the heated demineralized water main pipeline to the deaerator's water inlet. This invention uses demineralized water as a stable heat exchange cold source and completes efficient indirect heat exchange with high-temperature condensate within the heat exchange unit, significantly improving heat exchange efficiency, enabling systematic recovery of condensate waste heat, significantly improving the overall utilization rate of plant heat energy, and achieving tiered optimized heat allocation.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery and utilization technology, and in particular to a condensate waste heat recovery and deaerator heat optimization utilization system. Background Technology

[0002] In the utilities systems of chemical, petrochemical, and new materials production enterprises, the waste heat recovery and efficient utilization of condensate is a key link in achieving energy conservation and emission reduction, and ensuring stable equipment operation. The high-temperature condensate generated during production has significant waste heat value. Direct discharge or insufficient heat recovery not only wastes a large amount of heat energy but also increases the enterprise's energy consumption and operating costs, contradicting the current development philosophy of energy conservation, emission reduction, and green low-carbon practices in industrial production.

[0003] Currently, conventional condensate waste heat recovery systems mostly use demineralized water as a cold source for heat exchange, transferring the heat from the high-temperature condensate to the demineralized water to achieve the dual purpose of heat recovery and condensate cooling. However, in actual production operation, such systems generally suffer from the following technical defects: when production conditions fluctuate or the heat demand of upstream users is insufficient, the demineralized water used as a cold source cannot be consumed or transported in a timely manner, resulting in a lack of stable and matched cold source support for the heat exchange system. The heat exchange efficiency of heat exchange equipment such as plate heat exchangers decreases significantly, the high-temperature condensate cannot be effectively cooled, and the outlet temperature of the condensate after heat exchange consistently exceeds the design and safe operating range.

[0004] Excessively high condensate return water temperatures have several drawbacks. Firstly, they prevent the full recovery of waste heat from the condensate, resulting in significant heat loss with the incompletely cooled medium and low thermal efficiency, hindering the optimal allocation of heat across the entire plant. Secondly, prolonged operation at excessively high temperatures significantly increases the thermal stress load on heat exchange equipment such as plate heat exchangers, accelerating the aging and damage of seals and plates. This leads to frequent leaks, increasing maintenance frequency and costs, and impacting the continuous and stable operation of the entire condensate recovery and demineralized water supply system, posing safety hazards. Furthermore, directly feeding demineralized water that has not undergone sufficient heat exchange and preheating into the deaerator can cause flash evaporation and water hammer due to the mismatch between the water temperature and the saturation temperature at the deaerator's operating pressure. This further affects the deaerator's operational stability and deoxygenation efficiency, ultimately limiting the overall operational efficiency and economy of the utility system.

[0005] The existing technologies suffer from a series of problems, including insufficient cold source supply, incomplete condensate waste heat recovery, easy leakage of heat exchange equipment, and water hammer in deaerator makeup water. Currently, there is a lack of a systematic solution that is structurally sound, operationally stable, and adaptable to plant-wide heat optimization. Therefore, developing a technical system that can effectively solve the problem of insufficient cold source for condensate heat exchange, achieve full waste heat recovery, and ensure the safe and stable operation of the deaerator has become an urgent technical issue to be addressed in the field of chemical utilities. Utility Model Content

[0006] The present invention aims to solve the above-mentioned problems and provides a condensate waste heat recovery and deaerator heat optimization system.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problems is: a condensate waste heat recovery and deaerator heat optimization utilization system, including a deaerator, a condensate delivery pipeline, a demineralized water supply pipeline, and a heat exchange unit. Condensate is connected to the hot side inlet of the heat exchange unit through the condensate delivery pipeline, and demineralized water is connected to the cold side inlet of the heat exchange unit through the demineralized water supply pipeline. The demineralized water heated by heat exchange flows to the heated demineralized water main pipeline through the cold side outlet of the heat exchange unit. A water supply crossover is connected between the heated demineralized water main pipeline and the water supply port of the deaerator. The demineralized water flows to the water supply port through the water supply crossover. The temperature of the heated demineralized water matches the saturation temperature under the operating pressure of the deaerator. In addition to flowing into the deaerator, a portion of the heated demineralized water also flows to other users through the heated demineralized water main pipeline.

[0008] Furthermore, the condensate cooled by heat exchange flows out through the hot side outlet of the heat exchange unit and is transported to the subsequent reuse node through the condensate return pipeline.

[0009] Furthermore, the heat exchange unit is a plate heat exchanger, with condensate as the heat medium and demineralized water as the cold medium.

[0010] Furthermore, a control valve is installed on the water replenishment line.

[0011] Furthermore, the system also includes a main water supply pipeline, which is connected to the water supply inlet.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] This invention uses demineralized water as a stable heat exchange cold source and completes efficient indirect heat exchange with high-temperature condensate in the heat exchange unit. It effectively solves the problem of low heat exchange efficiency caused by the lack of corresponding heat users and unstable cold source supply in traditional processes. It enables the systematic recovery of the waste heat of condensate that could not be fully utilized, significantly improves the overall utilization rate of the plant's heat energy, and realizes the step-by-step optimization of heat allocation.

[0014] This invention reduces the condensate temperature to a safe operating range after heat exchange and cooling, avoiding the plate heat exchanger being in a state of overheating and large temperature difference alternation due to excessively high return water temperature. It significantly reduces the thermal stress damage and aging rate of heat exchange plates and seals, significantly reduces heat exchanger leakage and maintenance frequency, extends equipment service life, reduces daily operation and maintenance costs and maintenance workload, and improves the continuity and reliability of system operation.

[0015] This invention directly feeds the demineralized water, heated by heat exchange, into the deaerator via a water supply line, matching the water supply temperature with the saturation temperature under the deaerator's operating pressure. This avoids problems such as flash evaporation, severe water hammer, and pipeline vibration caused by direct water supply of low-temperature demineralized water, eliminates safety hazards such as equipment impact and pipeline damage, ensures long-term stable operation of the deaerator, and improves the deaeration effect and the inherent safety level of the system.

[0016] This invention utilizes the recovered condensate waste heat to directly heat the deaerator makeup water, effectively increasing the deaerator inlet water temperature and significantly reducing the heating steam consumption required for deaerator operation. It also reduces the power consumption of related auxiliary equipment, achieving a dual reduction in energy consumption and operating costs, and bringing stable and considerable energy-saving benefits and economic benefits to the device.

[0017] This utility model can achieve connectivity simply by adding pipelines and optimizing the connection method, without requiring large-scale modifications to the main equipment. It is easy to construct, has low investment, and is flexible in operation. At the same time, it can adapt to changes in operating conditions under different production loads. By adding control valves across the line, the flow rate and switching can be flexibly adjusted. It is applicable to deoxygenation and condensate waste heat recovery systems in similar public works projects in industries such as chemical and new materials, and has strong versatility and promising prospects for widespread application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the pipeline connection for the condensate waste heat recovery and deaerator heat optimization utilization system in this utility model.

[0020] In the diagram: 1. Plate heat exchanger; 11. Hot side inlet; 12. Cold side inlet; 13. Hot side outlet; 14. Cold side outlet; 2. Deaerator; 3. Condensate delivery pipeline; 4. Demineralized water supply pipeline; 5. Main demineralized water supply pipeline; 6. Condensate return pipeline; 7. Makeup water crossover; 8. Control valve; 9. Makeup water inlet; 10. Main makeup water pipeline; 15. Other users. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present utility model can be combined with each other, and the described embodiments are only some embodiments of the present utility model, not all embodiments.

[0022] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] See appendix Figure 1This embodiment describes a condensate waste heat recovery and deaerator heat optimization system, comprising a deaerator 2, a condensate delivery pipeline 3, a demineralized water supply pipeline 4, and a heat exchange unit. Condensate is connected to the hot-side inlet 11 of the heat exchange unit via the condensate delivery pipeline 3, and demineralized water is connected to the cold-side inlet 12 of the heat exchange unit via the demineralized water supply pipeline 4. The demineralized water, heated by heat exchange, flows through the cold-side outlet 14 of the heat exchange unit to the heated demineralized water main pipeline 5. A water supply cross-line 7 connects the heated demineralized water main pipeline 5 and the water supply inlet 9 of the deaerator 2, through which the demineralized water flows to the water supply inlet 9. The temperature of the heated demineralized water matches the saturation temperature under the operating pressure of the deaerator 2. In addition to flowing into the deaerator 2, a portion of the heated demineralized water also flows to other users 15 via the heated demineralized water main pipeline 5. Specifically, the condensate temperature in the condensate delivery pipeline 3 is 130℃; the demineralized water temperature in the demineralized water supply pipeline 4 is 40℃; and the demineralized water temperature in the heated demineralized water main pipeline 5 is 125℃. Besides flowing into the deaerator 2, some of the heated demineralized water also flows to other users 15 via the heated demineralized water main pipeline 5. During operation, the heated high-temperature demineralized water is directly supplied to the deaerator 2 via the makeup water cross-line 7. Because the makeup water temperature matches the saturation temperature under the current operating pressure of the deaerator 2, the medium will not undergo instantaneous flash vaporization after entering the deaerator 2, thus completely eliminating the water hammer, vibration, noise, and equipment impact hazards caused by direct makeup water of traditional low-temperature demineralized water, ensuring the continuous and stable operation of the deaerator 2, and improving the quality of deoxygenated water and operational safety.

[0024] By using condensate waste heat as the core heat source and demineralized water as the heat transfer medium, and through heat exchange coupling and pipeline optimization, the waste heat carried by the condensate is accurately recovered and transported to deaerator 2 for reuse, thus constructing a closed-loop system for the cascade utilization of heat throughout the plant. Demineralized water is used as a stable cold source for indirect heat exchange with high-temperature condensate, completely solving the heat exchange failure problem caused by the lack of corresponding users for demineralized water and insufficient cold source supply in traditional systems. By setting up a water supply bypass 7 directly connected to deaerator 2 on the main demineralized water pipeline 5, the high-temperature demineralized water after heat exchange can be directly supplied to deaerator 2 through this bypass without the need for additional cooling or temperature control equipment, realizing the direct transfer and efficient reuse of condensate waste heat to deaerator 2.

[0025] The condensate, cooled by heat exchange, flows out through the hot-side outlet 13 of the heat exchange unit and is transported to subsequent reuse nodes via the condensate return pipeline 6. Specifically, the condensate temperature in the condensate return pipeline 6 is 80℃. During the heat exchange process, the high-temperature condensate releases latent heat and sensible heat, reducing its temperature from the original overheated state to the set safe operating temperature range. The cooled condensate is then transported to subsequent reuse nodes via the condensate return pipeline 6, preventing thermal stress damage to downstream pipe networks and equipment caused by overheated media. This reduces leakage failures caused by temperature imbalance and overheating operation of plate heat exchangers, thereby lowering equipment maintenance frequency and operating costs.

[0026] The heat exchange unit is a plate heat exchanger 1, with condensate as the heat medium and demineralized water as the cold medium. The plate heat exchanger 1 has high heat exchange efficiency and compact structure, and is suitable for heat exchange conditions of high-temperature condensate and demineralized water. The heat exchange intensity can be flexibly adjusted according to the on-site operating load to ensure the continuity and stability of heat recovery.

[0027] A control valve 8 is installed on the water supply line 7. Preferably, the control valve 8 is a regulating ball valve or a shut-off valve. The control valve 8 installed on the water supply line 7 can adjust the water supply flow rate and switching status of the high-temperature demineralized water in real time according to the water supply requirements of the deaerator 2 and the system operating conditions, thereby improving the adjustability and adaptability of the system operation and meeting the heat recovery and water supply requirements under different production loads.

[0028] The system also includes a main water supply pipeline 10, which is connected to the water inlet 9.

[0029] This system, through the aforementioned process, transfers all the waste heat from the condensate that would otherwise be difficult to recover to the makeup water system of deaerator 2. This directly increases the inlet water temperature of deaerator 2, significantly reducing the amount of heating steam required to maintain its operating parameters. Simultaneously, it reduces the energy consumption of auxiliary equipment such as circulating pumps, achieving comprehensive optimization and cascaded utilization of heat across the entire plant. In actual operation, the system can adjust the flow rate of the heat exchange medium and the opening of the makeup water bypass by controlling valve 8 according to changes in production load, ensuring optimal heat recovery and operational stability under different operating conditions.

[0030] In this embodiment, all pipes, control valves 8, and heat exchange units are made of pressure-bearing and high-temperature-resistant materials that meet public works standards. Pipe connections are made using flanges or welding to ensure system tightness and operational reliability. After the entire system is put into operation, no dedicated personnel are required. Parameter monitoring and remote control can be performed using existing DCS systems, making operation and maintenance simple. It is suitable for public works deoxygenation systems and condensate waste heat recovery scenarios in chemical, petrochemical, and new materials production enterprises, and has strong practicality and promotional value.

[0031] A condensate heat recovery and deaerator heat optimization utilization system of the present utility model. The implementation logic and working principle of the makeup water temperature control scheme are described as follows:

[0032] In this application, the makeup water temperature of the demineralized water entering the deaerator after heat exchange and temperature rise is stably controlled by the method of dual - path mixing ratio adjustment of low - temperature demineralized water and high - temperature demineralized water. The system is equipped with an on - line temperature monitoring element to detect the total makeup water temperature after the mixing of the two paths of demineralized water in real time, and at the same time, the operating pressure and the internal water temperature of the deaerator are collected in real time. By adjusting the opening degrees of the regulating valves of the two branches of low - temperature demineralized water and high - temperature demineralized water, the mixing ratio of the two paths of makeup water is changed, and the final temperature of the makeup water after aggregation can be stably controlled, so that the makeup water temperature is always lower than the saturation temperature under the operating pressure of the deaerator, avoiding problems such as premature vaporization of makeup water and water hammer vibration from the root, and fully meeting the design requirements for the safe and stable operation of the system.

[0033] A condensate heat recovery and deaerator heat optimization utilization system of the present utility model. The following is a supplementary explanation of the stability of the deaerator working condition and the feasibility of the scheme:

[0034] The deaerator supporting this application is equipped with a mature operating pressure - heating steam inlet interlock control logic: when the external water supply volume of the deaerator and the device load fluctuate, the steam inlet regulating valve can automatically adjust the opening degree accordingly. When the pressure decreases, the steam is automatically opened wider for makeup, and when the pressure increases, the steam is automatically closed smaller to reduce steam makeup. Through this mature interlock control common in the chemical industry, it can ensure that the operating pressure of the deaerator is always maintained within a set stable range under all working conditions.

[0035] The inside of the deaerator is always in a steam - water saturated state, and its operating pressure and internal saturation temperature have a one - to - one corresponding saturated thermodynamic relationship. When the pressure is stable, the corresponding saturated temperature is also basically constant, and there is no situation of large - scale and frequent fluctuations in the saturated temperature, greatly reducing the difficulty of adjusting the makeup water temperature and further ensuring the stable and reliable implementation of the temperature control scheme.

[0036] The dual - path makeup water ratio control for temperature control and the deaerator pressure - steam interlock for pressure stabilization adopted in this application both belong to the conventional industrial control means of the makeup water system of the deaerator in chemical utility engineering. The control logic is clear and the adjustment method is mature. Those skilled in the art can stably implement the temperature control scheme of this application according to the system structure and pipeline connection relationship disclosed in the specification, combined with the general process control knowledge in this field.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A condensate waste heat recovery and deaerator heat optimization system, characterized in that: The system includes a deaerator (2), a condensate delivery pipeline (3), a demineralized water supply pipeline (4), and a heat exchange unit. Condensate is connected to the hot side inlet (11) of the heat exchange unit through the condensate delivery pipeline (3). Demineralized water is connected to the cold side inlet (12) of the heat exchange unit through the demineralized water supply pipeline (4). The demineralized water heated by heat exchange flows to the heated demineralized water main pipeline (5) through the cold side outlet (14) of the heat exchange unit. The heated demineralized water main pipeline (5) is connected to the water inlet (9) of the deaerator (2) by a water supply cross line (7). The demineralized water flows to the water inlet (9) through the water supply cross line (7). The temperature of the demineralized water heated by heat exchange matches the saturation temperature under the operating pressure of the deaerator (2). In addition to flowing into the deaerator (2), some of the demineralized water heated by heat exchange flows to other users (15) through the heated demineralized water main pipeline (5).

2. The condensate waste heat recovery and deaerator heat optimization system according to claim 1, characterized in that: The condensate after heat exchange and cooling flows out through the hot side outlet (13) of the heat exchange unit and is transported to the subsequent reuse node through the condensate return pipeline (6).

3. The condensate waste heat recovery and deaerator heat optimization system according to claim 1, characterized in that: The heat exchange unit is a plate heat exchanger (1), whose heat medium is condensate and whose cold medium is demineralized water.

4. The condensate waste heat recovery and deaerator heat optimization system according to claim 1, characterized in that: A control valve (8) is installed on the water supply line (7).

5. The condensate waste heat recovery and deaerator heat optimization system according to claim 1, characterized in that: The system also includes a main water supply pipeline (10), which is connected to the water supply inlet (9).

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