A combined system of high-temperature purification and reuse of steam condensate and low-temperature waste heat power generation

Abstract

The utility model discloses a steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system, which includes a high-temperature iron removal filter, a low-temperature waste heat power generation unit, a condensate collection box, an oil removal adsorber, a cation exchange resin purifier, an anion exchange resin purifier and a refined condensate collection box; the high-temperature iron removal filter is used to remove iron components in the steam condensate; the low-temperature waste heat power generation unit cools down the steam condensate after iron removal and generates waste heat; the oil removal adsorber, the cation exchange resin purifier and the anion exchange resin purifier respectively remove oil, cationic impurities and anionic impurities from the steam condensate. While the utility model cools down the steam condensate to be suitable for high-temperature purification treatment, it also recovers the waste heat of the steam condensate for power generation, meeting the purpose of steam condensate purification and reuse, and can be widely used in steam reuse purification in the process of indirect heating using steam.

Description

Technical Field

[0001] The utility model belongs to the application field of steam condensate purification technology, and specifically relates to a steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system, which is mainly used in petroleum, chemical and power enterprises. Background Art

[0002] During the production process, petrochemical enterprises need to use a large amount of steam as a heating medium. After the steam is used and condensed, it produces high-temperature condensate (generally 85-95°C). Due to the contamination of hydrocarbons, metal ions and other substances, most of them cannot be directly used. Due to the limitations of existing processes, the method of first cooling (generally to 40°C) and then purifying and reusing is usually adopted, resulting in low heat recovery efficiency and huge energy waste.

[0003] The above steam condensate is characterized by high calorific value, light pollution (usually oil content 10ppm, iron content 100ppb or less), and good quality (except for minor pollutants, the water quality meets the requirements of secondary desalted water). Therefore, the ideal recycling method is to reuse it as boiler feed water. Since boiler water has high requirements for reuse water quality (see Table 1), it can only be treated by resin ion exchange process. The temperature of petrochemical condensate is above 85-95℃. At such a high temperature, the thermal degradation rate of ion exchange resin is very fast and the service life is very short. The service life of anion resin at 90℃ is less than 2 months.

[0004] Therefore, when using ion exchange to desalinate high-temperature condensate from petrochemicals, the water temperature should be lowered first. However, the lower the water temperature, the greater the heat loss and the worse the economic efficiency of reuse. Since the condensate needs to be heated up before it can be reused as boiler feed water, the condensate reuse process should be kept as low as possible or cooled as little as possible to reduce energy consumption.

[0005] Table 1: Steam condensate purification standards

[0006]

[0007]

[0008] Another problem faced by steam condensate reuse as boiler feed water is oil removal. Since petrochemical steam condensate is inevitably contaminated by oil substances, activated carbon is usually used as the adsorption medium for oil removal. Ordinary activated carbon must be removed due to the dissolution of silicon and the serious wear of silicon on turbine blades, which will increase the resin exchange load. Therefore, the problem of silicon dissolution in activated carbon during the oil removal process must be solved.

[0009] In terms of condensate desalination, the strong alkaline anion exchange resin currently sold in the domestic and foreign markets is generally required to have an inlet water temperature lower than 45°C when used for water treatment, otherwise it will accelerate the degradation of the physical and chemical properties of the strong alkaline anion exchange resin and affect the long-term normal operation of water treatment. Even the developed high-temperature resistant anion exchange resin usually has a tolerance temperature between 80-90°C. Therefore, it is imperative to properly cool the steam condensate before purification. Since the inlet water temperature is required to be low, air cooling or circulating water heat exchange cooling is usually used, which requires a condenser with a large cooling area and wastes energy. Utility Model Content

[0010] In order to solve the problem of restricting the purification and reuse of steam condensate in the prior art and make full use of the waste heat energy and reuse value of steam condensate, the utility model provides a steam condensate high-temperature purification and reuse - low-temperature waste heat power generation combined system.

[0011] The technical solutions adopted are as follows:

[0012] A steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system, the system comprising:

[0013] High temperature resistant iron removal filter, used to remove iron components from steam condensate;

[0014] A low-temperature waste heat power generation unit is connected to the high-temperature resistant iron removal filter, and the steam condensate after iron removal is passed through the evaporator in the low-temperature waste heat power generation unit for heat release and cooling;

[0015] A condensate collection tank connected to the low-temperature waste heat generator set, into which the steam condensate after being cooled by the low-temperature waste heat generator set enters;

[0016] An oil removal adsorber connected to the condensate collection tank and used for absorbing and purifying oil and organic matter in the steam condensate;

[0017] a cation exchange resin purifier, connected to the oil removal adsorber, for removing cationic impurities from steam condensate;

[0018] an anion exchange resin purifier, connected to the cation exchange resin purifier, for removing anion impurities in the steam condensate;

[0019] The refined condensate collection box is used to collect steam condensate that meets the reuse requirements.

[0020] Furthermore, the system also includes a refined mixed bed, which includes high temperature resistant anion exchange resin and cation exchange resin, the inlet end of the refined mixed bed is connected to the outlet of the anion exchange resin purifier, and the outlet end of the refined mixed bed is connected to the inlet end of the refined condensate collection box.

[0021] Preferably, the low-temperature waste heat power generation unit is a magnetically levitated ORC low-temperature waste heat power generation unit, which includes an air cooler, a condenser, an evaporator, a heat source and a generator. The heat source is steam condensate after input iron removal, and the steam condensate is discharged to the condensate collection tank through heat release in the evaporator; the air cooler and the condenser form a first circulation loop through a circulating pump; the condenser, the evaporator and the generator form a second circulation loop through a working fluid pump, and the second circulation loop is used for the generator to generate low-temperature waste heat electricity and cool the heat source; the first circulation loop is used to cool the working fluid passing through the condenser.

[0022] Preferably, the high temperature resistant iron removal filter is provided with a replaceable modified polyester filter element.

[0023] Preferably, after the low-temperature waste heat power generation unit cools the steam condensate, the temperature of the steam condensate is reduced to 65-70°C.

[0024] Preferably, the oil removal adsorber is provided with replaceable acid-washed coconut shell granular activated carbon for removing oil and organic matter from the condensate. The acid-washed coconut shell granular activated carbon has the characteristic of low dissolved silicon (the silicon content of ordinary activated carbon after flushing with 100 times the bed volume of water is about 400-500 ppb, while the silicon content of this activated carbon is less than 50 ppb under the same conditions).

[0025] Preferably, the cation exchange resin purifier, anion exchange resin purifier and mixed bed purifier use exchange resins that can withstand 75°C;

[0026] Preferably, the exchange resin is an anion resin.

[0027] The technical solution of the utility model has the following advantages:

[0028] A. Steam condensate is an ideal heat transfer medium and is widely used in many industries such as petroleum, chemical industry, coal chemical industry, and electric power. It is also a key process unit for energy consumption in the industry. By removing oil, iron, anions, cations and other impurities from steam condensate (95°C), the steam condensate is cooled to be suitable for high-temperature purification treatment, and the waste heat of the steam condensate is recovered for power generation, so as to achieve the purpose of purifying and reusing the steam condensate. It can be widely used in steam reuse purification in the process of indirect heating using steam.

[0029] B. The utility model system is easier to implement. It can be implemented in a newly built device or modified on an existing device. The modification work is small. It only needs to add a low-temperature waste heat power generation unit and replace the purification medium. The original process flow remains basically unchanged.

[0030] C. The effect of the utility model system is remarkable. In the production process, petrochemical enterprises need to use a large amount of steam as a heating medium, and its energy consumption accounts for 30-40% of the total energy consumption of the enterprise. 3 / h of condensate as an example, its cooling by 20℃ requires 2545t / h of circulating water, so the annual circulating water cost is 4.46 million yuan (circulating water is calculated at 0.2 yuan / t); on the other hand, after refining, 1300m 3 / h condensate temperature increase 20 ℃ requires 45.3t / h of steam, the annual steam cost is more than 47 million yuan (steam cost is calculated at 120 yuan / t), therefore, the use of the utility model system has great economic and social benefits.

[0031] D. The utility model system has high feasibility. The development and production of high-temperature purification media and the use of low-temperature waste heat technology provide material conditions for the implementation of the utility model, meet the current energy-saving and consumption-reducing requirements, and have maturity and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present utility model, the drawings required for use in the specific implementation methods will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a system composition diagram provided by the utility model;

[0034] Figure 2 yes Figure 1 Illustration of the composition of medium and low temperature waste heat power generation unit.

[0035] The meanings of the symbols in the figure are as follows:

[0036] 1-High temperature resistant iron removal filter

[0037] 2-Low temperature waste heat generator

[0038] 21- air cooler, 22- circulation pump, 23- condenser, 24- working fluid pump, 25- evaporator

[0039] 26-heat source, 27-expander, 28-generator

[0040] 3- condensate collection tank; 4- oil removal adsorber; 5- cation exchange resin purifier

[0041] 6-anion exchange resin purifier; 7-refining mixed bed; 8-refining condensate collection box. DETAILED DESCRIPTION

[0042] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0043] like Figure 1 As shown, the utility model provides a steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system, the system includes: a high-temperature resistant iron removal filter 1, a low-temperature waste heat power generation unit 2, a condensate collection box 3, an oil removal adsorber 4, a cation exchange resin purifier 5, an anion exchange resin purifier 6 and a refined condensate collection box 8, the above-mentioned devices are connected in sequence, and the high-temperature resistant iron removal filter 1 is used to remove the iron component in the steam condensate. The high-temperature resistant iron removal filter is preferably provided with a replaceable modified polyester filter element. The modified polyester filter element is oleophobic, which is more conducive to iron removal and also reduces the risk of fouling and clogging of the heat exchanger. Therefore, the utility model arranges the high-temperature resistant iron removal filter 1 at the front end of the system.

[0044] The low-temperature waste heat generator set 2 is connected to the high-temperature iron removal filter 1. The steam condensate after iron removal is cooled by the evaporator in the low-temperature waste heat generator set. After the low-temperature waste heat generator set 2 cools the steam condensate, the temperature of the steam condensate is reduced to 65-70°C; the condensate collection box is connected to the low-temperature waste heat generator set, and the steam condensate after cooling by the low-temperature waste heat generator set 2 enters the condensate collection box 3; the oil removal adsorber 4 is connected to the condensate collection box 3, and the steam condensate after power generation and cooling (temperature 65-70°C) enters the oil removal adsorber 4. The oil removal adsorber 4 is preferably equipped with acid-washed coconut shell granular activated carbon, which is used to remove oil and organic matter in the condensate. The acid-washed coconut shell granular activated carbon has the characteristic of low silicon dissolution. The acid washing process can ensure that the soluble silicon in the carbon base can be removed, and the oil and organic matter in the steam condensate are adsorbed and purified by the adsorbent. When saturated adsorption is reached, the adsorbent is regenerated by conventional methods.

[0045] The cation exchange resin purifier is connected to the oil removal adsorber to remove cationic impurities in the steam condensate; the anion exchange resin purifier is connected to the cation exchange resin purifier to remove anionic impurities in the steam condensate; the refined condensate collection box is used to collect steam condensate that meets the reuse requirements. The utility model system achieves the purpose of purifying and reusing steam condensate by sequentially removing oil, iron, anions, cations and other impurities from the steam condensate (95°C). Figure 2As shown, the low-temperature waste heat power generation unit 2 is preferably a magnetic levitation ORC low-temperature waste heat power generation unit, which includes an air cooler 21, a condenser 23, an evaporator 25, a heat source 26 and a generator 28. The heat source 26 is the steam condensate after input iron removal, and the steam condensate releases heat inside the evaporator 25 and is discharged to the condensate collection tank 3; the air cooler 21 and the condenser 23 form a first circulation loop through a circulating pump 22; the condenser 23, the evaporator 25 and the generator 28 form a second circulation loop through a working fluid pump 24, and the second circulation loop is used for the generator 28 to generate low-temperature waste heat electricity and cool the heat source 26; the first circulation loop is used to cool the working fluid passing through the condenser 23.

[0046] Specifically, combined Figure 2 As shown, the steam condensate after iron removal enters the magnetic suspension ORC (Organic Rankine Cycle) low-temperature waste heat generator set, and is discharged after releasing heat in the generator set evaporator (cooling down 20-30°C); cooling water (closed cooling) is sent to the ORC generator set condenser from the cooling tower through a circulating water pump, and returns to the air cooler for heat dissipation after absorbing heat in the condenser. The cooled cooling water enters the condenser through a circulating pump and circulates continuously; the working fluid enters the evaporator from the condenser through a working fluid pump to absorb heat into steam, and then enters the expander 27 to expand and do work, driving the generator 28 to generate electricity, and the working fluid at the outlet of the expander 27 enters the condenser 23 to release heat and condense, and the condensed working fluid enters the evaporator 25 through a working fluid pump 24 and circulates continuously; the generator 28 is sent to the plant power system through a connecting line, and the steam condensate after cooling enters the condensate collection tank 3.

[0047] The utility model reduces the temperature of the steam condensate by 20-25°C and realizes waste heat power generation in the low-temperature waste heat generator set 2. At the same time, a second circulation loop is used to heat the working fluid in the low-temperature waste heat generator set 2 to realize heat exchange between the working fluid and the steam condensate, and the heat of the working fluid heating is used to realize power generation. The first circulation loop combined with the air cooler 21 and the condenser 23 circulates and cools the working fluid in the low-temperature waste heat generator set 2. The cooling and reuse requirements of the steam condensate are realized by combining the first circulation reflux and the second circulation loop. The utility model can be widely used in steam reuse and purification in the process of indirect heating using steam.

[0048] As a further preferred embodiment of the utility model, the system also includes a refined mixed bed 7, which includes a high temperature resistant anion exchange resin and a cation exchange resin, the inlet end of the refined mixed bed 7 is connected to the outlet of the anion exchange resin purifier 6, and the outlet end of the refined mixed bed 7 is connected to the inlet end of the refined condensate collection box 8, and the steam condensate (temperature 65-70°C) from which most of the cation and anion impurities are removed enters the cation and anion refined mixed bed 7 for treatment. Since the refined mixed bed 7 is filled with high temperature resistant (75°C) anion exchange resin and anion exchange resin, when saturation is reached, the resin is regenerated by conventional methods. After the steam condensate is purified by the refined mixed bed 7, it enters the refined condensate collection box 8, which can meet the requirements for the reuse of the steam condensate.

[0049] The above-mentioned cation exchange resin purifier and anion exchange resin purifier preferably use exchange resins that can withstand 75° C. When saturation is reached, the resin is regenerated using conventional methods.

[0050] After being treated by the system provided by the utility model, the pollutants in the steam condensate are removed, and the temperature is reduced to 20-25°C, making the steam condensate after the temperature reduction more suitable for cation exchange resin and anion exchange resin for water treatment. The utility model adopts low-temperature waste heat utilization technology (ORC) to reduce the temperature of 95°C steam condensate by 20-25°C, which not only meets the condensate temperature requirements of subsequent high-temperature purification technology, but also provides external power output. Usually, the utilization of low-temperature waste heat will bring about the economic irrationality of working fluid condensation for lower cooling requirements. After the utility model reduces the steam condensate to 70-75°C, it can be suitable for high-temperature purification process, especially to ensure the long-term operation of ion exchange resin. At the same time, when the steam condensate is reused, the heating energy can be greatly reduced. Therefore, the utility model achieves the dual goals of energy saving and steam purification, and at the same time adapts to the technical characteristics of low-temperature waste heat application, and can be widely used in many industries such as petroleum, chemical industry, coal chemical industry, and electric power.

[0051] The utility model system adopts low-temperature waste heat power generation technology to cool the steam condensate to an appropriate temperature and output electricity to the outside at the same time; after the steam condensate is properly cooled, a high-temperature purification process is used to purify the steam condensate, and a high-temperature resistant medium is used to purify the steam condensate to meet the requirements for the reuse of the steam condensate. Through the above combined process, the low-temperature waste heat of the steam can be effectively utilized to output electricity to the outside. At the same time, after the condensate temperature is lowered, it directly enters the subsequent purification unit without additional cooling, meeting the requirements of the subsequent purification process for the condensate temperature. This combined system not only realizes the recycling of high-value condensate, but also outputs electricity, has a good energy-saving and consumption-reducing effect, a wide range of applications, and is easy to promote and implement.

[0052] Anything not described in the present invention is applicable to the prior art.

[0053] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present utility model.

Claims

1. A steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system, characterized in that: The system comprises: High temperature resistant iron removal filter, used to remove iron components from steam condensate; A low-temperature waste heat power generation unit is connected to the high-temperature resistant iron removal filter, and the steam condensate after iron removal is passed through the evaporator in the low-temperature waste heat power generation unit for heat release and cooling; A condensate collection tank connected to the low-temperature waste heat generator set, into which the steam condensate after being cooled by the low-temperature waste heat generator set enters; An oil removal adsorber connected to the condensate collection tank and used for absorbing and purifying oil and organic matter in the steam condensate; a cation exchange resin purifier, connected to the oil removal adsorber, for removing cationic impurities from steam condensate; an anion exchange resin purifier, connected to the cation exchange resin purifier, for removing anion impurities in the steam condensate; The refined condensate collection box is used to collect steam condensate that meets the reuse requirements.

2. The steam condensate high temperature purification and reuse-low temperature waste heat power generation combined system according to claim 1 is characterized in that: The system also includes a refined mixed bed, which includes high temperature resistant anion exchange resin and cation exchange resin. The inlet end of the refined mixed bed is connected to the outlet of the anion exchange resin purifier, and the outlet end of the refined mixed bed is connected to the inlet end of the refined condensate collection box.

3. The steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system according to claim 1 is characterized in that: The low-temperature waste heat power generation unit is a magnetically suspended ORC low-temperature waste heat power generation unit, which includes an air cooler, a condenser, an evaporator, a heat source and a generator. The heat source is steam condensate after input iron removal, and the steam condensate is discharged to the condensate collection tank through heat release in the evaporator; the air cooler and the condenser form a first circulation loop through a circulation pump; the condenser, the evaporator and the generator form a second circulation loop through a working fluid pump, and the second circulation loop is used for the generator to perform low-temperature waste heat power generation and cool the heat source; the first circulation loop is used to cool the working fluid passing through the condenser.

4. The steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system according to claim 1 is characterized in that: The high temperature resistant iron removal filter is provided with a replaceable modified polyester filter element.

5. The steam condensate high temperature purification and reuse-low temperature waste heat power generation combined system according to any one of claims 1 to 4, characterized in that: After the low-temperature waste heat power generation unit cools the steam condensate, the temperature of the steam condensate is reduced to 65-70°C.

6. The steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system according to claim 5 is characterized in that: The oil removal adsorber is provided with replaceable acid-washed coconut shell granular activated carbon for removing oil and organic matter from the condensate. The acid-washed coconut shell granular activated carbon has the characteristic of low dissolved silicon.

7. The steam condensate high-temperature purification and reuse-low-temperature waste heat power generation combined system according to claim 2 is characterized in that: The cation exchange resin purifier, anion exchange resin purifier and refined mixed bed use exchange resins that can withstand 75°C.

8. The steam condensate high temperature purification and reuse-low temperature waste heat power generation combined system according to claim 7 is characterized in that: The exchange resin is an anion exchange resin.

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