Steam & Power Forum RSS Welcome to the steam & power forum, a bulletin board dedicated to power & heating plants, boilers, turbines, steam, HTHW, pressure vessels, HRSG, piping and condensate, combustion including ASME questions and more. 8/20/2017 10:29:05 PM Poppy at Steam & Power Forum RSS 64 150 Re: One question regarding low pressure Condenser - By: P I [1983] Consider the container like an enclosed container with pumping system to pump the leftover water out. The pressure inside is 0.9 barA saturation temperature of water at 5&#194;&#176;C. The external temperature is around 30&#194;&#176;C and we have to vent steam from inside to atmospheric level @ 1 kg/sec.<br />I just want to know how can I do the job with the least amount of energy spent on compressors. Sat, 19 Aug 2017 13:46:00 -0300 Re: One question regarding low pressure Condenser - By: Jim Watts [764] What percentage of the steam do you want to vent.<br />Ie How much is a part.<br /> Sat, 19 Aug 2017 05:47:00 -0300 Re: One question regarding low pressure Condenser - By: P I [1983] You have misunderstood what I want to mean. I have never mentioned anything about condensing steam turbine. What I have asked is for the best way to keep the pressure and temperature inside a Condenser lower with minimal energy cost for venting a part of the steam and non-condensables into atmosphere to keep the pressure inside at the desired level. Fri, 18 Aug 2017 13:26:00 -0300 Re: One question regarding low pressure Condenser - By: Jim Watts [764] There is no intercooler. <br />The condenser you are refering to is the first stage condenser the second stage ejector takes suction from. <br />Your interpretation of the process in a condensing turbine is extremely far from reality.<br /><br />The most efficient way to get steam out of a condenser is as water or alternatively not to put it in there in the first place.<br />Such turbines are called back pressure turbines and are used at the very high process efficiencies you are dreaming of.<br /><br /> Thu, 17 Aug 2017 09:24:00 -0300 Re: One question regarding low pressure Condenser - By: P I [1983] I want to know whats the power consumption of the process. What I can understand is that by intercooling we can reduce power consumption. What I want to is to vent steam from that low pressure to atmospheric level with minimum power consumption. I specifically how much stages would be most economic in terms of power consumption. Thu, 17 Aug 2017 08:57:00 -0300 Re: One question regarding low pressure Condenser - By: Jim Watts [764] Your question does not arise in the real world because the reason for using multi stage ejectors is because the maximum pressure ratio between suction obtainable on a single stage is 5 to 1.<br />This means two in series are required for most applications and three for for very low condenser pressure.<br />These devices are removing air and gases from the condenser and are not steam compressors.<br />A typical installation has a high capacity single stage ejector called a quick start or hogging ejector to raise vacuum quiickly and a two stage running ejector. The steam is condensed against condensate so no heat is lost.<br />Liquid ring vacuum pumps are often used instead of steam ejectors or in combination where depending on economics.<br /> Wed, 16 Aug 2017 10:26:00 -0300 Re: Reverse power - By: Murphy [21] Simply, the steam turbine will be damaged for it will be spinning at high speeds without steam because there will be no steam demand so the throttle will be closed. I dont think the turbine can be run for very long without steam because it will overheat as stated earlier by Watts. That circuit breaker on the AC generator has to open for I would fear speed regulation to be an unacceptable condition too. The likely damaging scenarios are just not pretty. What a good question... Wed, 16 Aug 2017 08:31:00 -0300 Re: One question regarding low pressure Condenser - By: Murphy [21] I cant, but high efficiencies tend to be driven by colder environments which are passed on to the low pressure condenser that pull greater vacuums as a result and of course lower hot well temperatures. Wed, 16 Aug 2017 08:22:00 -0300 Re: One question regarding low pressure Condenser - By: P I [1983] Can you tell me about the most efficient in terms of power consumption Cold below ambient level Condenser working at present? Tue, 15 Aug 2017 03:52:00 -0300 Re: One question regarding low pressure Condenser - By: Murphy [21] This question seems to have been answered over 2 centuries ago, but needs to be addressed from time to time. The basis of your question is rooted in economics for yesterdays local economies seem vastly different from todays global economy. But no matter what the local economy still drives the decision to install main condenser with auxiliary machinery such as steam powered air ejectors with after-condensers, inter-condenser and gland exhaust condensers versus using a after condenser with steam powered ejectors and even then electric motor powered are now installed. Even now who wouldve thought some 50 years ago that air cooled condensers would be a substitute for a large surface condenser.<br /><br />Without a doubt condensers are very important sense the inventor, Mr. Watts, developed the Newcomen engine who finally installed a jet like condenser to improve his steam engine efficiency. In the two centuries since then reciprocating steam engines became equipped with main condensers and auxiliary condenser machinery to improve the functions of the main condenser efficiency. Those included air ejectors, after condenser, inter-condenser and gland exhaust condenser. The arrangements would be determined by the need to decrease the cost of operating the plant.<br /><br />Might be worth noting that the primary function of an efficient condenser is the production of condensate from low-pressure steam and maintaining a production of condensate with efficient heat transfer. The secondary function of the condenser is the collection of condensate to conserve water. Sometimes a third function is specified such as an old term that is called vacuum dragging where the power of the vacuum in the main condenser is utilized in the facility or plant.<br /><br />Global financing and a companys internal rate of return to finance the additional capital for auxiliary machinery versus fuel cost with lifecycle cost is showing in recent times that minimizing capital equipment and machinery is cost-effective versus the modest savings from installing and operating such capital equipment and machinery. This seems to be a trend. Also whats troubling is the life expectancy that is used in the feasibility study of a plant that would use such capital.<br /><br />Im hoping that others will answer your question more directly but I think it would be hard to expect hard numbers. Good luck Murphy. Mon, 14 Aug 2017 14:45:00 -0300 Re: Rupture disc damage - By: Jim Watts [764] I probably should add the amount of air to cause this problem is only the amount to blanket the tubes and prevent normal steam condensing. Mon, 14 Aug 2017 03:27:00 -0300 Re: Rupture disc damage - By: Jim Watts [764] If steam entered the condenser under vacuum as designed it would condense and no problem.<br />It is most likely the piping to the condenser was full of air under pressure. This would have nowhere to go apart from the disks as the ejector is too small for such an event.<br /> Sun, 13 Aug 2017 18:44:00 -0300 One question regarding low pressure Condenser - By: P I [1983] At present, low pressure condensers are in use to enhance power generation in steam turbine based power plants and its often found that steam compressors are attached to them to suck out extra steam out of the Condenser to keep the pressure level inside stable.<br />What I want to know that what is more effective in terms of commercial aspect for such plants. A single condenser or multiple condensers with intercoolers. A single Condenser means huge power consumption and that may offset the power gain by the lowering of pressure at the Condenser. Multiple condensers fitted with intercoolers may decrease the power consumption drastically but can increase the cost dramatically and they are more complex to set and maintain.<br />As for example, if the pressure level at the Condenser is set at 2.536 kPa saturated steam pressure at 20&#194;&#176;C, then it would take around 1.3 MW of power to make just 1 kg/sec steam flow In comparison, three compressors in series fitted with intercoolers can suck out around 2 kg/sec steam flow from 1.29 kPa pressure. But that means three times the cost and more complex system.<br />Those who have some real life experience in such matter kindly tell me which one is better in terms of real use. Sun, 13 Aug 2017 11:49:00 -0300 Re: Reverse power - By: Salman Rafique [2169] What would happen if reverse power detected but generator CB will not trip or open. What are the possible damages if this condition occurs. Thu, 10 Aug 2017 15:07:00 -0300 Re: Steam Power Plant - Rupture Disk on Steam Turbine Casing - By: Salman Rafique [2169] What are the other reasons of brusting disc rupture except cooling water flow, condensate pumps fault or steam injections after Turbine Trip.<br /> Thu, 10 Aug 2017 14:28:00 -0300 Rupture disc damage - By: Salman Rafique [2169] Recently our steam turbine condenser, rupture disc was damaged while taking HP steam bypass valve in service, intialy steam dumps to condenser through dump tube for turbine startup, at 52Barg pressure when HP BYPASS valve just starts open ~3% suddenly condenser vaccum breaks while all other parameters were normal like Cooling water flow, condensate pumps etc. Please share your comments in this regards<br /><br /> Thu, 10 Aug 2017 14:22:00 -0300 Re: Gas turbine output - By: Ross Burns [390] Great responses. I wish to add that should you want to fog the inlet to the compressor just ahead of the 1st stage for the gas turbine, which was also call evaporative cooling, then keep in mind if it gets out of hand you can destroy the 1st stage of the compressor or at the very least damage it to such an extent that it has to be replaced. This is similar to online washing of the compressor, but different, and only very clean or purified water can be used for a online wash. I think you probably already know that... Thu, 27 Jul 2017 16:35:00 -0300 Re: Bagasse boiler furnace design - By: Ross Burns [390] I think you know you will need at least a hired consultant to help you design your steam generator to burn or combust Bagasse. A big boiler manufacture is really needed to complete your design in detail and commissioning.<br /><br />Sugar cane has sugar like raw juice lock in with the leafy matter or leafy pulp that we call Bagasse, which is a waste by-product. It has a low Btu per pound content of around 4000-Btu per lb. There is a lot of water in Bagasse of around 50 percent making combustion difficult. Interestingly, wood bark has twice the Btu per lb as Bagasse, but has about the same moisture amount. So dewatering Bagasse to some extent is something to consider, but we can still have stable combustion at 65% moisture content.<br /><br />You may want to consider blending your Bagasse during combustion with wood or coal depending on local conditions.<br /><br />The lower furnace is likely to be grated with traveling grates or vibrating grates which are well suited for biomass like Bagasse, but others are not. <br /><br />The rest of the boiler or steam generator is pretty much the same as burning coal or wood.<br /><br />Ross <br /><br /> <br /> Wed, 26 Jul 2017 12:38:00 -0300 Bagasse boiler furnace design - By: all [2166] Hi, How are you dear members.<br /><br />I need information about bagasse boiler furnace design. Equations, reference values, etc.<br /><br />Thanks. Wed, 26 Jul 2017 10:49:00 -0300 Re: When is Power Engineer Required in a Building - By: Murphy [21] You re welcome. Wed, 26 Jul 2017 08:30:00 -0300