tag:blogger.com,1999:blog-3126847305205297792.post2169962011926492094..comments2023-10-26T08:26:50.122-07:00Comments on Energy Engineering Blog: Sustainability and Cement CO2 emissions: US cement outlookUnknownnoreply@blogger.comBlogger8125tag:blogger.com,1999:blog-3126847305205297792.post-89158377278462131582012-11-15T22:46:31.552-08:002012-11-15T22:46:31.552-08:00Informative and interesting which we share with yo...Informative and interesting which we share with you so i think so it is very useful and knowledgeable. I would like to thank you for the efforts. I am tiring the same best work from me in the future as well. idateasiahttps://asianbeauties.jux.com/noreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-11998689751334915452009-01-05T17:05:00.000-08:002009-01-05T17:05:00.000-08:00Lilian,As far as I know, foundry sands should not ...Lilian,<BR/>As far as I know, foundry sands should not contribute to heavy metal emissions. I do not have direct experience in air quality issues, but does the EA check the air quality around the town regularly? <BR/>I think the main issue is to know what is being emitted and establish if the emissions are toxic. Various heavy metals end up in different places during the cement production process depending on the volatility.TheLighthttps://www.blogger.com/profile/18019559931842016011noreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-25733095538501351782008-12-30T08:00:00.000-08:002008-12-30T08:00:00.000-08:00HelloAnyone out there know, or able to guesstimate...Hello<BR/>Anyone out there know, or able to guesstimate, what the impact is on the emissions of dust from five mills and separators of blending in all sorts of "toxic" fillers like fly ash, and bypass dust from the co-incinerating cement industry? If you look at www.rugbytown.org you can see a 2 million tonne a year Cemex plant that was built and operated in 2000 without a valid planning or operating permit. Year on year production increases as do the HGVs and the use of waste fuels and industrial waste substitutes for raw materials such as slag, mill scale, aluminium dross, foundry sand etc, and of course emissions also increase, but most are unmonitored and only "sampled" twice a year.<BR/><BR/>You can see that it is very close to the town and has many vents and stacks as well as the main 115 metre stack. The stack emits about one million cubic metres gas each hour - or more - and the low level sources emit about another 600,000 cubic metres an hour of particulate laden gas/air in "what they call pure air".<BR/><BR/>The EA refuse to give us any information about the emissions from the mills and LLPS and they say continuous particulate monitors were fitted about 2 years ago. Cemex however say that RMC fitted these monitors in 2004. Which is true - anyone's guess! But they both refuse to allow us to see any data from these emission sources, but we have found out several occasions when the twice yearly contractor does the tests as in the permit and finds sometime the mills running at SEVEN times the permitted 30 mg/m3, i.e. at 20,000 micrograms/m3. The local people are frequently covered in thick sticky dust and they refuse to tell us what is in it and refuse access to information which heightens the very real suspicion that they are dumping even more pollution on us than we can find out about.<BR/><BR/>They also break the ELVs for the main stack for dioxin, particulate, etc and we are very concerned about the dust that is coming out of the stack and also particularly from the LLPS - with all the waste blended into the clinker. There is also mercury and arsenic etc from main stack and the UK's EA says it has no capability of testing for these pollutants - even chromium 6 etc though the USA EPA does test and recently found the Davenport Cemex plant to be emitting high levels of this cancer causing agent from the burning of mill scale and slag as a replacement for the iron oxide.<BR/><BR/>Has anyone got any idea, or any peer reviewed reports, about the impact on the emissions from all these substitutions in the mills. They also refuse to give us the mandatory EU waste catalogue number and just keep on saying misleading things - like the bypass dust is not hazardous, even though they know it is.<BR/><BR/>Any help anyone please?<BR/>Thank you.<BR/><BR/>LilianAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-68388685709732290022008-12-12T13:17:00.000-08:002008-12-12T13:17:00.000-08:00Gerald,Interesting idea. The cement process techno...Gerald,<BR/>Interesting idea. The cement process technologies I know of involve direct-contact heat exchange. <BR/><BR/>IMO, essentially, the function of the preheaters and precalciners is to increase the effective length of the kiln, so that drying and calcination can happen much earlier in the process..this increases the plant output for a given energy input.<BR/><BR/>What you propose might be feasible with oxy-fuel combustion. Here, instead of burning the fuel in an atmosphere of air, the combustion takes place in a O2:CO2 atmosphere.<BR/><BR/>Apart from the challenges of figuring out the clinker:CO2:O2 chemistry to preserve the clinker quality, cryogenic air distillation plants have a big energy/land foot print.<BR/><BR/>In this context, novel air separation processes become significant. For example: Air Products' ion transport membrane (ITM).<BR/><BR/>I should also point out that capture of the CO2 does not lead to carbon credits, it is the effective storage or utilization component that closes the deal.TheLighthttps://www.blogger.com/profile/18019559931842016011noreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-76199312631008513402008-12-12T07:17:00.000-08:002008-12-12T07:17:00.000-08:00Because the calcination process in cement producti...Because the calcination process in cement production makes up about 60% of the CO2 released (40% from combustion)it would be very useful to have separate streams,(calcination and combustion). Basically not allowing the two gases to mix in the process. The calcination component would be relatively pure and could be geologically stored. Under this concept cement manufacturers could make much headway toward the future cap and trade goals (europe, and soon to be in the USA). The capture component of CCS is very expensive, around $40/ mt. One might also use some of the calcined component as a scrubber in the combustion stream with regeneration on the calcination side. There has been a lot of work done on preheaters and precalcination, but this all needs to go to the next step.<BR/><BR/>What do you think?<BR/><BR/>Gerald the geologistAnonymoushttps://www.blogger.com/profile/02366455828684433375noreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-50927177656369782272008-11-25T21:43:00.000-08:002008-11-25T21:43:00.000-08:00@Anonymous:"I think you ignore the concentration o...@Anonymous:<BR/>"<I>I think you ignore the concentration of metals in coal fly ash like Mercury that make disposal in cement kilns - which have no Mercury pollution controls - unattractive.</I>"<BR/>Fly ash is milled with cement clinker and gypsum in a separate step downstream of the cement kiln. Therefore, there is no danger of the mercury volatilizing at high temperatures. Most of this mercury (Hg) ends up in the cement concrete. I have not looked for studies claiming Hg releases from concrete products specifically.<BR/><BR/>I think Class C fly ash is considered safe enough to make bricks (which replace the coal-fired clay bricks), <A HREF="http://www.greenestbrick.com/" REL="nofollow"> The Green Brick Company </A> already does this.<BR/><BR/>BTW, most of the Hg in the coal ends up in the vapor/gas phase, at least for coal combustion. <BR/><BR/>About cement kilns not having Hg controls, the conversations I have had with people in the industry indicate that the EPA is still looking into this and will probably come up with a ruling.<BR/><BR/>Using saw grass etc: This is a good option, if the saw grass is cheaper than coal or other fuels. However, fuel contributes to ~4% of the CO2 emissions of cement kilns, most of the CO2 emissions are a result of the raw material calcination. Cement production and concrete manufacture essentially is as follows:<BR/>1. Mining limestone, clay, alumina etc.<BR/>2. Milling the raw materials in desired proportions.<BR/>3. Calcining the limestone to form lime (CaO), and further reactions of the lime with silica and alumina forming calcium {alumino) silicates (clinker).<BR/>4. Milling of the clinker with additives (fly ash, gypsum, limestone) to produce various grades of cement.<BR/>5. Mixing this cement with sand, and other aggregates to produce concrete.<BR/>6. As the concrete ages in buildings, it reacts with atmospheric CO2 and water and undergoes hydration. The CaO in cement reacts slowly with CO2 forming calcium carbonate again. <BR/><BR/>Essentially, in the overall cement life cycle, man takes CO2 out of CaCO3, forms calcium (alumino) silicates and Nature puts CO2 (and water) back into the mix slowly.TheLighthttps://www.blogger.com/profile/18019559931842016011noreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-2073789529232036612008-11-25T20:42:00.000-08:002008-11-25T20:42:00.000-08:00I think you ignore the concentration of metals in ...I think you ignore the concentration of metals in coal fly ash like Mercury that make disposal in cement kilns - which have no Mercury pollution controls - unattractive.<BR/><BR/>Also, what about bio-fuels like Sawgrass, etc?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3126847305205297792.post-85704075774539329832008-11-25T01:49:00.000-08:002008-11-25T01:49:00.000-08:00Most of the cement companies involved operate faci...Most of the cement companies involved operate facilities in multiple markets, including many developing economies. As the Initiative moves from research and planning to implementation, it is expected that smaller cement companies will be recruited to join and participate, both for training and technology transfer purposes. Participants would be engaged in guideline formulation, establishing monitoring and reporting programs, and communicating results.<BR/>--------------------------<BR/>adolfo<BR/><A HREF="http://www.drivenwide.com" REL="nofollow">SEO</A>Unknownhttps://www.blogger.com/profile/05539223801352393752noreply@blogger.com