Some brief information on the steam recovery unit, to share and learn together**

Thread Content

This post was last edited by LQ198619 on 2017-7-26 at 23:39. Recently, the company has decided to install a waste steam recovery system aimed at capturing the flash vapor emitted from systems such as those used for asphalt production, catalysis processes, boilers, and condensate water. In the past, this vapor, which consisted of saturated steam at low pressure and temperature mixed with air, was simply released into the atmosphere without any utilization. Now, in response to the call for energy conservation, as well as to reduce production costs, lower the steam consumption in the production systems, and minimize white pollution, the company has opted to implement waste steam recovery. Since we had no prior exposure to this kind of knowledge, I went ahead and found some materials on the topic to study*, so that I could communicate with others in the future. I’ll share these materials with everyone for us to study together; I hope it will be helpful to all of us. Superheated steam, which possesses thermal potential energy, is introduced into the turbine through pipes, where it converts this thermal potential energy into kinetic energy. High-speed flowing steam drives the turbine rotor to rotate, generating mechanical energy. The steam that releases thermal potential energy is discharged from the exhaust port at the lower part of the turbine, and is known as waste steam. The pressure of the waste steam is at atmospheric pressure – 0.4 MP, and the temperature is below 150 degrees. The steam recovery unit is designed for the thermal cycle in thermal power plants: after the condensate and deionized water are heated and deoxygenated in the deaerator, the non-condensable gases are discharged into the atmosphere through the exhaust pipe. During the process of removing non-condensable gases, a large amount of noise is generated, contaminating the environment; at the same time, some steam is also expelled, resulting in waste of energy. 1. Surface contact type: Thermal energy is recovered through contact heat exchange. This method has a low recovery rate, and it requires a large amount of cooling water during the processing; the resulting condensate also needs to be sent back to the condensate recovery system. 2. Direct mixing type: Waste steam is directly mixed into the medium that needs to be heated in order to recover its thermal energy; this method is simple but has a very low recovery rate. 3. Heat storage tank type: The waste steam is stored in a large-capacity water storage tank, and secondary steam is generated through flashing for reuse; the recovery rate can reach up to 30-40%. The remaining condensed water needs to be pressurized before being recycled back into the system. 4. Jet type: A jet-type waste steam recovery device is composed of components such as a housing, nozzles (single or multi-hole), and mixing tubes. Utilizing the dynamic head of the cooling water, the spent steam is recovered back into the equipment through a suction-injection method via a built-in venturi tube. When the cold liquid passes through the nozzle, its high flow velocity creates a low pressure at the throat section, which draws in steam. This steam then mixes further with the cold liquid in the mixing tube, thereby enabling the recovery of low-pressure steam to be used for heating the cold liquid. Since this is a venturi-type process, the back pressure remains at atmospheric level, so it does not affect the normal discharge of process waste steam. The jet-type waste steam recovery device is a type that is widely used these days; below is a simple flowchart for your reference. http://down.hcbbs.cc/attachment/forum/201706/10/203353z7y06fdo70r6eod0.jpg Petrochemical zone —— New ideas for energy savings: the “Creative Thinking” campaign (the second phase is in full swing). http://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1666758 (Source: Haichuan Chemical Industry Forum) 2017: “My Technical Upgrades” in the coal chemical industry. http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum Website) Registration for chemical engineers – Experience sharing: the “Learning from Others’ Experiences” campaign. http://bbs.hcbbs.com/thread-1808158-1-1.html (Source: Haichuan Chemical Industry Forum Website)