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Energy systems thinking a new design
Helios 11001214249
48 Posts
Question
Hi I would like to ask the community if we can set up a post for a new energy system I have been working on ,I think it works out more efficient and ecologically better , and its large scale thinking for energy systems , and now I need to check through my figures and need the views of IET thinkers for instance on combustion , post combustion chemistry , it unfolds into quite a complex system which I have been working on for 8 years , but enables us to get more energy from wastes and perhaps helps to move to biomaterials. I have an interest as environmental thinker and have designed the system to go through to government funding phases and pretty confident it works well in a number of questions around energy and environmental thinking .
32 Replies
Simon Barker 22060613
645 Posts
Helios:
Hi I would like to ask the community if we can set up a post for a new energy system I have been working on

I think you just did.

Helios 11001214249
48 Posts
Hi Simon thanks , the request hung in the air for a while but then appeared , my first blog so have to forgive any media use errors 
Helios 11001214249
48 Posts
Ok am trying to think how to do this , some technology I cant really discuss until end of June when published , but I guess getting agreement on the toolbox I have made should help to express the interactions that enable the efficiency so at least you get an idea of the combustion efficiencies .I don't know if a good starting point is to look at one of the most impressive coal fired plants where supercritical steam parameters are used , the J W Turk plant in Arkansa USA won an award in 2012 and it is quite a bit of engineering for coal technology ,Using PRB coal at around 21000 KJ/KG at a rate 350,000kg /Hr , producing 600MW and putting out 444,756 kg of CO2 every hour plus NO2 , estimate as air drafted atl air/ fuel ratio of 8:1 , air at 1.225 kg/m3 around 2,800,000 kg hr or 3,430,000 m3 , being as air is composed of 78% N2 and 21% O2 so around 2,709,700m3 of N2 and 720,000m3 O2 .The O2 is of course the component that reacts . This shows an obvious efficiency problem , even with re heat of incoming air ,the N2 component in air drafting plays little part in the actual heat aspects, add in if you have variations of external air temperatures and in air drafted systems you have ,thermal efficiencies to think about ,In the case of the J.W.Turk plant this is around 40MW from a day say at external air temp of 20oC to a night say of 2oC , inherent also is the fact that the N2 component of air is heated only to carry heat to the exhaust . The J.w.Turk plant given the planning time involved , it took nearly 2 years just to build the water curtain boiler ,really is a great engineering achievement , steam pressures to turbine of 26200 KPA supercritical steam at 607oC and 557kg/s .It is claimed that supercritical steam enables less fuel to be burnt and so is better for emissions , however fossil fuels and particularly coal are not really choices for countries to make anymore.
Carbon capture is interesting until you start thinking about the maths in fuel use terms where you start having figures of 15% plus extra coal burning and emissions just to sequester the CO2 into spent gas fields , so even to a lay person kinda burning 15% more fuel sequester CO2 means your stores run out of space faster and when your store is full what do you do then .
The other interesting fact for most air drafted electricity generating plants is how KJ of fuel is converted into KW of electrical output and most plants around the world have the rather terrible figure of 32-36% fuel energy to electrical output , the very best are at 45% and if you use CHP systems then maybe 60% , so these sorts of plants are incredibly poor at thermal efficiency. Because the J W Turk plant is burning the plentiful supply of low grade coal it produces fly ash and this is collected from the exhaust , it is thought that around 16% of the heat energy created is lost in so called stack losses, although where you use this to pre heat incoming air , as many plants do you get some improvements .
I make the total heat for this plant at 350,000kg x 21000 kj/kg = 7,350,000,000 KJ/hr with around 1,470,000,000 kj hr being in the exhaust assuming a standard 80% heat conversion boiler (don't know the heat recovery back to incoming pre heating)  , but around 80% of the heat energy used is converted in heat of the steam . so around 1mw uses 12,250,000 kj of fuel .
the MW and MWH understanding at point of generation , I could do with some better framing , is 600MW the continuous output ? so is my 12,250,000 kj per Mw , fuel figure correct ?
Also been trying to work out post combustion gas flows , and I get 1m3 of CO2 at NPT being 8m3 in volume at 500oC but unable to work out heat content in KJ per m3 at 8m3 expansion ?? I have had a go at ideal gas calcs but doesn't really help me with KJ per m3 . Have some other toolbox builder for combustion calcs later  and a whole host of other technical thinking if required.
Thanks for any help
Hi Simon Barker,
What is this about, and what system?
Simon Barker 22060613
645 Posts
Benyamin Davodian:
Hi Simon Barker,
What is this about, and what system?

I think you've asked the wrong person.

Came from your email.
Through the link I answered.
Simon Barker 22060613
645 Posts
Benyamin Davodian:
Came from your email.
Through the link I answered.

I have no idea what email you are talking about.  I haven't sent one.
The IET may have sent you an email if you're subscribed to this forum.  But I am not the one who made the original post; it's not my thread.

Helios 11001214249
48 Posts
Lets add a few combustion figures assume NPT
biomass (10% moisture) around 16000kj/kg (to include waste wood.,paper,straw,) (stoich combustion at est 1m3 of O2  per kg of Bm)
Bio solids (15-20% moisture) around 7000 kj/Kg (stoich combustion est at 1.2m3 of O2 per kg of BS)
CH4 around 39,000 kj/m3 (stoich combustion at 2m3 of O2 per m3 of CH4)
ethanol 23400 kj/lt  (stoich combustion is 1.26 m3 of O2 per lt)
Hydrogen (g) 12700 kj/m3 (stoic combustion is 2m3 of O2 per m3 of H2)

The figure trying to get hold of is Refuse derived fuel or RDF ,I guess its similar to low grade coal at around 21,000kj/kg so stoich O2 use will be around 1.4m3 of O2 per kg of RDF  ???
 
Even of you are trying to make the combustion process more efficient, isn't the core issue the burning of low grade, dirty coal, with all the polluting emissions which include GHGs, sulphurs, NOx, particles, mercury, et al?
https://www.csu.edu/cerc/researchreports/documents/EmissionsOfHazardousAirPollutantsFromCoal-FiredPowerPlants2011.pdf

Is making a dirty emissions coal power plant more efficient the right thing to be doing, rather than perhaps converting it to biomass, etc? UK Drax power station has converted to biomass, might be worth some investigation and useful information to learn from.
 https://www.drax.com/technology/switch-power-station-off-coal/
Helios 11001214249
48 Posts
Opps stoich figure for Hydrogen combustion is 0.5 m3 of O2 per m3 of Hydrogen , my apologies

1 kw equals 3600kj/hr so 1mw equals 3,600,000 kj/hr
So 500MW equals 1,800,000,000 kj/hr (that is if you could convert at 100% efficiency) 
The latest GE/Siemens H class gas turbines claim to convert 64% of fuel value Kj into Kw (but lets call it 60% to help visualise things) so at 60% efficiency our gas turbine is consuming 1,800,000,000 kj x0.4 === 2,520,000,000 kj , as methane is around 39000kj a m3 so something like 65,000 m3 of Ch4 is consumed for a 500MW turbine (and around 65000 m3 of CO2 every hour is made and a kj per Mw fig of 5,040,000KJ),  This beats our coal fired plant at 500Mw it would be emitting around 350,000kg /hr of CO2 or 190,000m3/hr , in fact in Co2 terms per MW its more than twice as good as air drafted electricity generation plants.
But this might not be the whole story if I stick with Methane and a 500Mw power plant can I beat the gas turbine ?? well a gas steam boiler could be more efficient ,than a boiler that has to burn a solid fuel so a 90% boiler should be possible, our J W Turk plant requires 12,250,000 KJ per Mw , so 500Mw should be around 6,125,000,000 kj , however a 10% more efficient boiler means 10% less fuel or 5,512,500,000 kj  so around 141,000 m3 /hr as an air drafted system. 
But what if we use an oxy fuel system ?? , no nitrogen to heat up , complete combustion ( I would need to do some complex gaseous heating equations at this point but lets call the removal of N2 to be worth a 14% reduction in fuel. so 121,550 m3 of Ch4 , the gas turbine is still twice as efficient at this point in fuel use terms , and a stack loss of 10% (4,740,450,000,kj === 4,740,450 000 x .0.1 =474,045,000kj ) if we could recover this exhaust heat and put it back into the combustion ,then only 4,266,405,000 kj would be required or 109,395m3 of CH4

Ok everyone happy with workings so far ??  
Helios 11001214249
48 Posts
Hi Maurice , I note a new coal plant is due to open in Germany this week, biomass itself isn't necessarily clean in emissions but is carbon neutral as a fuel , Drax is really interesting , next year it will stop burning coal and go 100% biomass and its hoping to fit CO2 scrubbers for a CO2 capture and store idea , but I just don't get this CO2 capture and store idea , I mean if you have to use more energy to capture the CO2 you will be making more CO2 to do this. at the moment Drax as a baseload plant is strategically important at 9% of uk electricity needs its done a  very good job , but as each new wind farm comes on line and combustion efficiency improves  , its design is becoming unsustainable, I mean if we used modern combustion designs plant we could up the efficiency conversion of fuel to KW , drax could burn the same amount of biomass but get 15-20% more electrical output , although 1 power plant supplying 12% of the uks electricity may be isn't where we want to go , Drax may be in entirely the wrong place now as demands are now mostly urban ones with much less heavy industry. It may be that we could save more energy , by moving power stations closer to demands and reducing line losses.  , 
Helios 11001214249
48 Posts
RDF figure I have got is around 15000 kj/kg and around 1.2 m3 of O2 per kg of RDF(20% moist) , but it is a guide as its quite a mixture depending on how your waste sorting is  1,5 kg of CO2 per KG combusted.

Ok lets do a combustion run well use a 500mw example needing 6,125,000,000 kj hr . 80%efficient boiler
Biomass 16,000kj/kg around 383,000 kg hr req 383,000m3 if O2  giving 635,014 kg of CO2 and 243,000 kg of H20 
RDF  at 15,000kj/kg around 408,000kg hr req 489,000m3 of O2 giving 612,000 kg of CO2 and 258,264 kg of H2O (20% moisture)
CH4 at 39000kj/m3  around 157,000 m3 hr req 314,000 m3 of O2 giving 289,000 kg of CO2 and 236,756 kg of H20 
Ethanol 23434 kj/li around 262,000 litres/hr req  323,832 of O2     giving 394,000 kg of CO2 and 242,612 kg of H2O
Bio solids at 7000 kj/kg  around 875,000 kg and hr 1,050,000 m3 of O2 per hour giving 830,375 kg of CO2 and 617,750  Kg of water 

every one happy at these ?
Helios 11001214249
48 Posts
Ok then lets have a think about fuel availability , so if we can co fire at say 40% CH4 and 60% solid fuels (comprised of 20% Bio mass 20% Bio solids and 20% RDF ) as an approximation for a 500MW 80% boiler as follows.(values at NPT)

CH4 62800m3 per hr using 125600m3 of O2 (154,000kg) giving 62800m3 of CO2 (34000kg) and 94577 kg of H2O
Bio Mass at  76600kg hr using 76600m3 of O2 giving 127000kg of CO2 and 48488kg of H2O
Bio solids at 175000kg/hr using 210000m3 of O2 giving 166000kg of CO2 and 123550 kg of H2O 
RDF at 81600kg/hr using 97800 m3 of O2 giving 122400kg of CO2 and 51650 kg of H2O 

giving a total o2 requirement of around 510000m3 hr (678800kg)
giving a total CO2 of around 450000 kg (244000m3) 
giving a total water of 318000kg (318m3 )

In reality fuel availability may vary , bio solids is pretty regular (excuse the pun ) as should RDF with the right fuel processing systems throughout the country , Biomass is perhaps the more variable probably getting more during summer when construction industry is going strong , but more interesting availability would be if we use it as building material more and then in 50-100yrs we start to get more regular biomass coming through and as a carbon store biomass would be sequestering CO2 giving both a safe and useful carbon capture system over a long time span .The O2 use figure may be high but its the amount of non carbon atom that we make into oxides , mainly nitrogen and sulphur which are difficult to determine ,the High O2/CH4 combustion temperatures will greatly aid thermal decomposition enabling the furans and benzenes to be decomposed to simpler molicules.
ta daa everyone still happy ??
Simon Barker 22060613
645 Posts
ta daa everyone still happy ??

I suspect that the number of people reading this who actually know enough to check your figures is very small.

Andy Millar 33788107
1713 Posts
Simon Barker:
ta daa everyone still happy ??

I suspect that the number of people reading this who actually know enough to check your figures is very small.

And any that do probably aren't going to comment! We live in a commercial world (even academics live in a commercial world) where ideas are money and business survival. No-one wants to discuss ideas in public, because that's letting knowledge escape to competitors. So the way this needs to work is that anyone with a potentially new idea needs to identify key potential partners, get them interested so that they don't feel that they are wasting their time, and then both sides need to get NDAs set up to protect them (there's lots of literature around about this stuff now). 

Which begs the question, how do you get potential partners interested? Theoretically one way is to "tease" on this forum, but actually a quick read through the posts here shows that the number of posters who are likely to be able to help is very small. A very common, and often quite successful, way is to present at conferences and seminars - let's face it, this is one of the main reasons why people present at these! (The other reason is simply to market their product or service.)

And then there's the phenomenally hard way, but which can sometimes work, which is to directly approach companies in the field. You need a lot of resilience for this, because you will get knocked back a lot. I ran an R&D team for many years, and I was continuously being approached by individuals, companies from other fields, and university researchers all of whom had wonderful ideas that they knew were much better than our current offerings. Being a helpful and collaborative chap I spent many hours talking to such people in my early years in the role, and what I discovered time and again was that the reason they thought their solution was so good was because they hadn't really understood the problem. As I say, I really like having those conversations, and am always optimistic that something might come out of them, but even I got frustrated in the end and started avoiding them. Engineering managers and business leaders just haven't got the time. SO if you take that path you must have something really well thought through and ideally somewhat proven to take to the company, including costings, so that you can show it is really worth their time.


Personally I'd love to have a forum where new ideas can be discussed openly, I believe (rightly or wrongly) that it would be better for society as a whole. But that's not the way society is set up. So for example on here I'll happily discuss audio circuit design (and in fact I do very actively on another group's forum) because these days that's a hobby and not the day job, but if anyone wants my opinion on a novel train detection system or level crossing system I'd have to direct them to my business address! And it will be the same for people working in the energy field.

Hope that helps, good luck,

Andy

Helios 11001214249
48 Posts
Hi Andy thankyou for that , the journey of this idea has been similar to as you outline ,of course you have to speak with an NDA sort of thinking ,my favourite one was speaking to a guy with 3mn in renewable assets (city investor type) and he just didn't get it , he didn't think combustion efficiency could be improved, I have applied for at least 3 guest speaking slots at various energy conferences and even though they say its for Green technology they just don't give you the opportunity to show the efficiencies for collegiate examination. I even explained to the government science body but they didn't understand it either but didn't say the efficiencies were wrong . I suppose we shall see but looking at the climate patterns for last year and the pollution aspects governments will be asked to act differently , if that 2.5oC target is missed the climate outcomes will be very bad for business and then all those who have sat back and said/did nothing , will be in the dock.   
Helios 11001214249
48 Posts
Hi Ho Hi Ho its off to work we go and its Monday hope everyone had a good weekend , I think we now have a 500MW power station capable of burning a variety of low grade wastes , at 6,125,000,000 KJ/Hr and an 80% efficient boiler means that 1,225,000,000 KJHR is lost as so termed stack losses , which could be exiting the furnace at anything from 200-400oC .
Each 1kg of water at 100oC makes 0,8m3 of water vapour , we have 318,000kg of water in our model so that's 254,400 m3h of water vapour however at around 300oC this would be double so 508,800m3 /hr as water vapour at 300oC same goes for the CO2 at 300oC of 488,000m3 , so perhaps a total gas/vapour of 996,800m3 hr  or 16,613m3/min or 278 m3 sec .

But we still might have smoke/char uncombusted so If we combust again but this time using CH4 and O2 in a 90% efficient boiler , flame temperatures of 1800oC plus then we can pretty much break down (thermally) any organic chemistry molecule still present , into simpler molecules/oxides .A further third stage of combustion would ensure even the most difficult wastes could be thermally decomposed , I doubt we could use another 500MW modelling so lets use 250MW using around 50,000m3 of CH4 /hr and using 100,000m3 of O2 (plus any excess required) producing 50,000m3 of Co2 (100,000m3 at 300oC )and 75,000kg of water (60,000m3 of water vapour at 100oC , 120,000m3 at 300oC)

So we now an exit exhaust at the third stage of 998,000 m3 plus a further 200,000 m3 of CO2 and 240,000m3 of H20 at 300oC giving around 1,440,000 m3 /hr , 24,000m3 min , 400m3 sec, at the third stage exit of exhaust ,containing the culmative 950,000m3 of water vapour at 300oC , will be carrying considerable heat in the water vapour , which can be recovered an reused .

potentially then a theoretical 3 combustion stage 1000mw power plant making 440,000 m3 of CO2 (238,000kg) per hour (at NPT) and 440,000kg of H2O (at NPT), that is nearly half the CO2 output of the J.W Turk plant and 40% more electrical output. By using concurrent combustion , the stack loss of the previous stage is utilised , as well as getting the thermal decomposition to simpler molecules , and no NOX emissions and we can burn most of our organic problem wastes to simple molecules.   
Helios 11001214249
48 Posts
May be, but it is the IET ask the community blog , so someone can look through them , its rough thermal workings at the moment .
but thanks 
Lots of numbers way beyond my ability or concentration span, and probably most audiences.

What people will be interested in is what is the additional cost of all the closed loop, recycling, more efficient combustion and energy recovery processes?

If this all costs >100% more or 5-10% extra output, it is just a theoretical nicety and not practical or pragmatic. What is the extra overall cost v extra overall efficiency and reduced GHG output and GHG CCS benefit?
Simon Barker 22060613
645 Posts
And it's even less worth it if the extra electricity used to run the extra plant is more than it generates.
Helios 11001214249
48 Posts
yeah done some figures I guess around 200Mw to get the O2 and cooling , so around 800Mw to grid if you want , but there are so many variants and I hope I can improve on fuel figures .
Helios 11001214249
48 Posts
I guess the basic start point is we need to dispose of wastes or recycle things , high temperature thermal decomposition works , and I think I can tune it better for lower fuel use , if we use spent bio materials (from a biomaterials economy) it should at least be carbon neutral , which works ok for the electric car and I think we have a process for making CO2 into a building material , I can increase the electrical output if required . I mean the packaging industry has done some great stuff with biomaterials , and at the moment biomaterials , that on second use make a fuel , seems a good solution .
But if it is not cost effective and makes a good business case, it is just virtue signalling no matter the environmental benefits. Have you done any cost benefit analysis?
 
Helios 11001214249
48 Posts
OH I have done some runs more efficient than this, cost benefit analysis wise it works ok , as it can be fuelled by even the most difficult wastes , so the benefit is not allowing culmative wastes and reducing landfill , and in cost terms it is more than a single air drafted plant , but they are base load and with heat recovery could have a figure of near 50% KJ energy to KW energy , so be really useful in green hydrogen production , although its better renewables be used for green hydrogen production via water electrolysis., if I can make a building material out of the CO2 (a form of plaster board)it works out even better. 
Helios 11001214249
48 Posts
Or sequesters the CO2 into useful products , that would otherwise require energy to make them .

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