Seeking advice on the use of heat pumps

Additionally, it is to be determined whether hot water at 130 degrees can be reduced to below 80 degrees using heat pump technology or other treatment methods, without considering the addition of fresh water!

I have just completed a project of this type, in which the condensate water is flashed again; this not only lowers the temperature of the condensate but also allows for the recovery of some steam. However, to reduce the temperature to below 80 degrees, multiple stages of flashing are required, which I consider unnecessary – as long as there is no cavitation during the pumping of the condensate water, that’s sufficient.

Pumps of this type should not be referred to as hot water pumps; they should instead be called condensate pumps. The products manufactured by Shenyang Condensate Pump Factory are of good quality (the name of the factory isn’t exactly correct – I’ll check that for you). Their structure and associated systems are somewhat complex. We have also chosen a condensate pump from Shanghai Sino-German Pump Industry; it hasn’t arrived yet. Its impeller is not made of bronze, but according to the manufacturer, it has good cavitation resistance. You might want to consult these two companies.

Also, I’m not sure how the original poster recovers the steam condensate – what is the specific process? In the project I just completed, the temperature of the condensate was still quite high; it was around 156 degrees before flash evaporation, and still around 135 degrees after that. During the testing phase, there was severe cavitation in the pump, intense vibration in the pump and pipelines, and frequent damage to the pump seals. If you could provide more details, I’ll see if I can help.

I. Steam usage instructions: 1. Steam enters the equipment via the main steam pipeline (DN200); the total amount of steam used is 25.6 tons per hour. Upon entering the equipment, the steam is divided into two systems for high-pressure and low-pressure use, with the condensate from the high-pressure system flowing into the low-pressure system after flash evaporation. The condensate from the low-pressure steam system enters the low-pressure condensate tank; the vapor produced after flashing is drawn in by a steam jet pump, mixed with other fluids, and then reintroduced into the low-pressure steam utilization system for reuse, while the condensate from the low-pressure condensate tank is discharged outside. 2. The steam consumption for each stage is detailed in the flowchart. II. Technical requirements: 1. Maximum recycling of steam is required, but the amount of steam entering the individual heat exchange units must remain unchanged. 2. Through technical treatment, it is required that the temperature of the water discharged from the condensate tank be kept below 70°C. 3. Technical treatment notes: Cooling the steam condensate allows for the use of additional equipment, but in order to minimize operating costs, it is preferable to rely on heat exchange with large amounts of cooling water.

Please let me know your email address on the upper floor so that I can send you the flowchart! My email address is: hzjdlsw@126.com

My email is sunhaowen2005@sina.com

Oh, okay!!!! I’ve sent it to you already!

All the steam condensate tanks of this equipment have this problem! The condensate tanks beneath each reboiler operate at atmospheric pressure and with open tops; flash vapor is lost, resulting in poor cavitation performance of the hot water pumps! The condensate tank is equipped with a safety valve that allows operation under pressure; moreover, the flow of condensate from certain reboilers to the condensate tank is not smooth, which affects operations! Using a steam-jet heat pump to recover secondary flash vapor is a good approach; I am very interested in learning about this process. Is the condensate tank operated at atmospheric pressure with an open top? How is a steam-jet heat pump controlled? How to control the temperature after flashing? Does a heat pump draw in air? Please give me some advice!

I would like to ask where the condensate water from the original poster goes? If the water is sent to the boiler’s pure water storage tank, undergoes deoxygenation treatment, and then is fed into the boiler itself to generate steam, it would be advisable to use a heat pump; instead of cooling the water to 70 degrees, keep it at 130 degrees and feed it directly into the deoxygenation tank! 1. Save a large amount of cooling water. 2. Reduce the inlet temperature of the feed pump for the deaeration tank. 3. Reduce the load on the feed pump for the deaeration tank. It is necessary to consider whether the capacity of the heat pump is sufficient to pump the condensate water into the deaeration tank.

There are two issues here: First, if the temperature of the hot water is 130°C and the pressure in the condensate tank is high, it may not be permissible from a process perspective. II. After the condensate is recovered in our company, it goes before the deionization resin process; this is to prevent the situation where, in case of a leak in some other equipment that isn’t detected in time, organic substances end up entering the deaerator and then the boiler, thereby contaminating the steam.

The value of steam condensate: Beijing Condensing Power Technology Co., Ltd. is currently the only high-tech enterprise in China dedicated to the development of technologies for condensate recovery, offering integrated services that include research and development, design, production, installation and commissioning, as well as after-sales support. The condensate recycler and low-pressure thermal deaerator introduced by Beining have effectively solved the world-wide problem of pump cavitation – often referred to as the \"cancer of pumps\". They have passed the technical evaluation conducted by the Beijing Science and Technology Commission; their condensate recycler, low-pressure thermal deaerator, and related system engineering technologies are considered to be internationally advanced solutions. These products are efficient and energy-saving, and they have been designated as key environmental protection technology projects by the State Environmental Protection Administration. Moreover, they have obtained multiple patents, serving as alternatives to conventional condensate tanks and high-pressure thermal deaators, which are characterized by high energy consumption and low efficiency. The technologies and corresponding equipment for steam condensate recovery, integration of high and low pressure pipelines, automatic pipeline pressurization, centralized drainage, pipeline anti-corrosion, separation of hot oil from water, and thermal deaeration at low temperatures, which were invented by the company’s chairman and chief engineer, Li Shusheng, and are used exclusively by our company, represent a completely new set of technologies and solutions to address energy waste in steam piping systems. Over the past few years, these technologies have been adopted by numerous users in more than 20 provinces and cities across the country, yielding significant benefits in terms of energy savings and environmental protection ； In 1998, it was designated as an EMC energy-saving demonstration project by the \"World Bank/Global Environment Facility China Energy Conservation Promotion Project.\" Funds provided by the Global Environment Facility (GEF) and the World Bank were used to help users in Beijing overcome funding shortages, thereby creating a \"production line\" for project replication and accelerating the development of energy conservation and environmental protection efforts. I. Main Products 1. NSQ—Condensate Recycler: Used for the completely sealed recovery of high-temperature condensate and secondary steam. 2. DRC---Low-level thermal deaerator: Used for high-standard deaeration in steam boilers. 3. Fixed-drain boiler heat recovery unit: Combines traditional fixed-drain and continuous-drain systems to make the most of thermal energy. 4. Boiler chimney waste heat recovery unit: Recovers the heat contained in the flue gases after combustion. II. Qualifications and Achievements 1. In 1998, in a public international bidding process conducted by the World Bank/Global Environment Facility for the Beijing Xiangyi Project, Beining won the bid; three thermal energy technologies developed by them were the first of their kind both in China and abroad. 2. On January 6, 1999, the Science and Technology Daily reported that China had overcome the world-wide challenge related to pump cavitation ； 3. Interview in “Beijing Energy Conservation” in May 1999: A Pioneer in Paving New Paths for Energy Conservation and Environmental Protection——Li Shusheng ； 4. In 1999, the World Bank/Global Environment Fund held public tenders in China, the United States, the United Kingdom, and Japan; Beining won the bid thanks to its closed-system design, which enables maximum energy savings, as it repeatedly rejected the open-system steam-generating equipment used by the United States and the United Kingdom ； 5. April 2, 2001, Science and Technology Daily: Beining Technology Solves Century-Old Problems ； 6. On April 21, 2004, a promotion meeting for Beining technology was held in the press conference hall of the Great Hall of the People. 7. Evaluation by a professor at Tsinghua University: “Similar technologies in the UK, the US, and Japan result in open waste of thermal energy and environmental pollution.” Beineng technology is a closed system with no pollution at all. ” 8. The core of the Beining technology is to develop thermal engineering’s \"static theory\" into a \"dynamic application theory,\" in order to address the challenge of having no computational methods for thermal engineering multiphase flows (including two-way flows). 9. Included in the **-level Torch Program by the Ministry of Science and Technology. 10. Listed as **key environmental protection technologies by the State Environmental Protection Administration; classified as projects exempt from approval by the World Bank/Global Environment Facility. 11. Included in Beijing’s plan for promoting major scientific and technological achievements by the Beijing Municipal Science and Technology Commission. 12. Has obtained ISO9001 and ISO14001 certifications. III. Condensate Water Recycler (I) Effects of closed-loop condensate water recovery: ① Efficient heat recovery. In traditional open-loop recovery systems, the large amount of secondary steam generated inevitably consumes a corresponding amount of condensate water; not only is a significant amount of latent heat of vaporization wasted, but this hot water also carries away a considerable amount of latent heat. The high-temperature condensate obtained from closed-loop condensate recovery has a pressure close to the steam pressure of the equipment that uses it; at the corresponding boiling point, the enthalpy of the condensate is higher, whereas at the same boiling point under normal pressure, the enthalpy of water is lower. Closed-loop recovery does not cause changes in enthalpy due to pressure drops, resulting in a large amount of secondary steam. At the same time, it prevents new steam losses caused by steam trap leakage (national standards allow a leakage rate of 3%), thus resulting in a high heat recovery efficiency. ② Water resource recovery is thorough. Open-loop recovery generates a large amount of secondary steam, which necessarily consumes an equivalent amount of condensate; therefore, the closed-loop recovery method enables the recovery of more water. At the same time, it prevents the unsightly and environmentally harmful phenomenon of large amounts of steam escaping in winter in the northern regions, as well as avoids corrosion of the factory buildings and peeling of walls caused by steam. ③ The quality of the recovered thermal energy is high. Due to the high operating pressure in the closed recovery system, the temperature of the recovered condensate water is high, which allows for significant savings in steam used for heating once it is delivered to the thermal deaerator. It is even possible to achieve zero steam consumption in thermal deaerators. ④ Improve the operating conditions of the pump. The closed-loop recycler operates under pressure; this pressure acting on the pump’s inlet helps to prevent cavitation in the pump. Additionally, this pressure can be converted into effective head for the pump, thereby reducing its power consumption. A cavitation elimination device has been installed inside the tank, thereby minimizing the possibility of cavitation. ⑤ It helps improve the quality of the recovered condensate. The closed recovery system is isolated from the outside world, which prevents the entry of impurities ； It can also prevent corrosion of the system caused by the entry of harmful gases such as O2, SO2, and NO. ⑥ It helps to stabilize the operation of steam-using equipment. When an open-type recovery device operates as a trap, it can easily cause pressure fluctuations and changes in flow rate of steam within the steam-using equipment; this is one of the factors that lead to leaks in heat exchange equipment, and it may even result in a suction effect that facilitates mass transfer between different substances. A closed-loop recycling system can effectively prevent this from happening. ⑦ Mechatronic operation is convenient, beneficial for environmental protection, and conducive to clean, civilized, and leak-free operations. (II) Advantages of the condensate recycler 1. Automatic pressure regulation device: The Beineng technology separates equipment safety from process safety, using safety valves to ensure the structural safety of the equipment and pressure regulation devices to guarantee the system safety of the production process. To ensure a positive pressure head of over 2 meters at the pump inlet, an automatic pressure regulation device is installed in the water collection tank. This device makes use of multiple-stage water seals and the \"U\"-tube principle; what’s different is that it contains several one-way pressure valves. The pressures of these valves are of two types: one is the zero-pressure type, with PN=0.01–0.09 MPa, and it is commonly used in condensate recovery systems with pressures below 0.1 MPa, such as those in central air conditioning systems for heating or lithium bromide refrigeration ； One type is the pressure type, with PN=0.1–0.8 MPa, and it is commonly used in thermal system projects in industries such as petrochemicals, steel, and thermoelectric power. The valve pressure is designed separately based on the residual pressure, and the valve body is made of stainless steel. While ensuring normal return of water, appropriately increasing the valve pressure is beneficial for the secondary condensation of vapor within the container; it represents an important energy-saving measure for flash recovery ； Secondly, the secondary steam exerts pressure on the water surface to ensure the positive head of water necessary to prevent cavitation in the water pump ； Third, a closed system is established to ensure there is no oxygen in the equipment and pipelines, thereby preventing rusting. 2. Dirt removal device: Since the volume of the water collection container is smaller than that of the condensate tank it replaces, hard particles such as rust damaged the pump impeller during early tests. Therefore, a dirt removal device for removing oil and impurities is added to the water collection container to improve the purity of the water. 3. Cavitation elimination device: When the water level in the centralized container drops to the bottom, a funnel-shaped depression appears immediately on the previously calm water surface (similar in shape to a tornado), and cavitation still occurs in the secondary pumping system. Based on the test results obtained by observing the color changes in transparent fiberglass and water, and using the Archimedes spiral equation as a theoretical basis, multi-layer conductive structures made of stainless steel ensure that the upper conductive structure automatically closes off when the water level drops, thereby preventing cavitation at low water levels. This device is a cavitation elimination device. 4. Pump modification: To meet the requirement of installing a dual-motor pump beneath the water collection container, I modified the existing single-stage pump. Firstly, the pump’s inlet pipe was moved from its original position on the side to the top, while the outlet pipe was moved from the top to the side, thereby creating an optimal flow pattern ； Secondly, the pump body is sealed with fluororubber, raising the temperature resistance from 80°C–110°C to over 160°C, thereby enhancing the pump body’s resistance to heat and wear ； Third, the pump base is changed to a lightweight version and fixed directly to the channel steel at the bottom of the equipment. As can be seen from the overall structure, the automatic pressure regulation device maintains a specific pressure within the water collection container. Under the influence of gravity and secondary steam pressure, the condensate is pumped into the pump via the cavitation elimination device, thereby eliminating entirely the conditions that allow high temperatures to cause cavitation in the water pump under negative pressure. 5. Automatic control: PLC programmable controllers produced by German Siemens are used. Schneider’s low-voltage electrical equipment is safe, reliable, and highly automated. IV. Low-level thermal deaerator. The high-level thermal deaerator has been the most widely used deaeration device both domestically and internationally over the years, but it has serious shortcomings: its installation height of 7–14 meters results in high civil engineering costs. It involves high lifting difficulties and a long construction period, among other issues. Currently, as urban fuel and gas boilers are rapidly replacing coal-fired boilers, it is urgent to change the installation location of deaerators from high positions to lower levels. Furthermore, since the condensate recycler recycles both high-temperature condensate and secondary steam in a closed system, the original high-pressure deaerator (typically at 104°C) is unable to meet the actual need for closing off high-temperature water before it enters the boiler. Beining’s uniquely designed low-pressure thermal deaerator addresses the aforementioned shortcomings as well as the global problem of pump cavitation, thereby extending the service life of pumps. This deaerator is designed at zero elevation and can be installed either above or below ground, reducing construction costs by over 80%. Standard practices over the years have dictated that the water tank be placed above the water pump, thereby providing a static head that helps prevent cavitation in the pump. Research and experiments show that static head exists in a static state, while pump cavitation occurs under negative pressure. Static and dynamic conditions cannot coexist on the same device at the same time; therefore, it is impossible to use the static head under static conditions to address pump cavitation under dynamic conditions (see Figure 1). As the water in the high-level tank accelerates from a stationary state to high-speed flow before the pump (at 2950 revolutions per minute), the cross-sectional area through which the water flows shrinks rapidly. The hot water vaporizes instantly under negative pressure, generating numerous bubbles; these bubbles burst upon entering the pump under pressure. The impact frequency around the water particles exceeds 20,000 times per minute, and the pressure in such a small area can reach several dozen to hundreds of megapascals. This extreme mechanical force exerts a severe impact on the impeller, causing it to be damaged very quickly. Cavitation generates a harsh noise and intense vibrations. (1) The five innovations of the Beining low-level thermal deaerator: A. Low level: It features a unique second-generation cavitation elimination device that enables installation at a low level; this prevents cavitation in the water pumps, reduces construction costs, incorporates mechatronics, allows for quick installation, and facilitates maintenance. It is the ideal auxiliary equipment for coal, oil, and gas boilers. B. Medium pressure: Based on the principle of multi-stage water seals, a liquid level-controlled overflow device was invented to replace the traditional water seal made up of three steel pipes; this solves the problem of insufficient water seal effectiveness and enables the creation of a closed medium-pressure deoxygenation system. At the same time, medium pressure helps to generate secondary steam or new steam from the condensate, thereby exerting pressure on the water surface and ensuring the positive water head necessary to prevent cavitation in the water pumps. At this point, almost no make-up steam is required for deoxidation, which is equivalent to an increase in the boiler’s output of 3%-4%. C. Reboiling device: The improved reboiling device enables rapid heating when the deaerator is restarted, allowing all residual oxygen to be removed from the water, thus ensuring safe and reliable operation. D. High deoxygenation efficiency: In the past, the oxygen discharge pipes of high-pressure thermal deoxygenators were of the open type, with the stop valves remaining open; as a result, the oxygen discharged accounted for less than 1% of the total exhaust steam, leading to significant waste of fresh steam, thermal pollution, and very low energy utilization efficiency. The oxygen discharge pipes of the low-temperature heat exchangers produced by Beining are equipped with electric valves that allow for timed and controlled oxygen discharge, depending on the specific conditions. This approach not only achieves high standards of oxygen removal but also reduces waste of new steam by 60%-80%. Contact: Wang Fei, 13691561221