H2 MIXING WITH FUEL REDUCES CO2 EMISSION? 4

[RED007]

Dear Friends,
i just entered into industry. we had problem with amount of co2 emission in power plants, where some generators are running with diesel,some with gas and some with duel fuel. i read a short description about the addition of H2 to fuel gas reduces the amount of co2 emission.does anyone knows about this process. our primary aim is to reduce the amount of co2 releasing to atmosphere, as it is costing the company a lot. your advise and references are much appreciated.

thanks and regards

 

[klem]

Hydrogen burns without emitting CO2, but CO2 is emitted when it is made by steam reforming of HC's or coal gasification. Adding H2 to a fuel just shifts where the CO2 appears. Reducing CO2 puts you in the CO2 business if you absorb it, or reduces production if you lower it by cutting power. You are on the horns of a dilemma, and need to study your whole plant system to reach an answer. You may also consider revamping power generation to a gas-steam turbine train to improve efficiency, which will reduce CO2.

 

[RED007]

Dear friends,
i finally decided to recover the CO2 from the collection of fluegases emitted, by inter-connecting the flue gas stream lines.according to many suguetions, i'm planing to use MEA as solvent in scrubber,but now i want help in finding a complete process description and thermal data related to the design of complete recovery of CO2. as i said before, we have a emission data per year, so per suppose the flue gas emitting from one plant contains: CO2=120000 tonnes/year,CH4=324 tonnes/yr,H2S=14 tonnes/yr, CO=3452 tonnes/yr, VOC=120 tonnes/yr, but from the ISO turbine specification the exhaust mass flow rate is 150 to 390Kg/hr and temperature is 485 Deg.Centigrade.(you can find these details for Mars 100 turbine generator on:

http://esolar.cat.com/solar/cda/art...html?prevTemplate=&userMessage=#javascript:).

Is it correct to estimate the exhaust pressure with the available V=390kg/hr and t=485 deg.C by using ideal gas eqn PV=nRT and from the above emission data we can find weight fraction of each compound, and multiplied by total mass flow rate gives the individual mass flow rate of each.please coment on this. i request all my elders and respected engineers to help me.i also request you to sugest at what concentration MEA can more efficiently absorb CO2 under economical conditions and what should be the required inlet pressure of gasmixture in a scrubber for efficient recovery?

thanks and regards,
RED007.

 

[TD2K]

I'm not familar with technology on CO2 removal from flue gases but I would have serious reservations about blowing hot gas turbine exhaust, typically containing about 15% oxygen, through a solution of MEA because of oxidation problems.

As raised earlier and assuming your design works, what are you going to do with the CO2 rich stream off your regenerator after you've removed it from the exhaust gases?

 

[TD2K]

Red007, suggest you fire up your browser and do some looking on the Internet.

"CO2 removal from flue gases" has lots of hits

http://www.co2captureproject.org/news/documents/GHGT 6 CCP Post Combustion Refinery.pdf

http://www.netl.doe.gov/publications/proceedings/01/carbon_seq_wksp/Rochell_Sep.pdf

http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/2b3.pdf

The last article has some information on estimating column sizing.

Two cautions. One, you still need to decide what to do with the removed CO2. Secondly, you are talking about some significant capital costs. Have fun reading.

 

[zqew05]

RED007,

Sir, I am not an Engineer but I do work on Solar Mars turbines offshore. Since you mentioned fines for exceeding CO2 emmissions I assume you work in a European country which signed the Kyoto Protocol Agreement. I work in the U.S. Gulf of Mexico where even though my country is not part of that agreement, the government standards are very strict nontheless. Your best bet is to contact Solar because they have been asked this question so many times and they may already have solutions to offer. Ask them how much it will cost to upgrade your turbine to SoLoNox turbine, the added weight is negligible. I mentioned weight because offshore floating facilities have weight constraints, a major reason they use turbines instead of diesel engines. Every added weight at my facility has to be proposed, studied, then seek approval from USCG and ABS. Dual-fuel Mars turbines use natural gas as primary fuel and diesel as cold-start emergency backup, so diesel emmissions are negligible. Ask your Solar technician to go into the PLC logic and tune the PID for fuel control, but usually this part has been tweaked very well after commissioning. After all the American-bashing that went on several years ago, many highly-advanced countries have violated the Kyoto Agreement they signed, because they found out the technology is not there to reduce emmissions. I agree with the others, you are being told to solve a problem for PR purposes. I hope you are not being set up as a fall guy. There are two kinds of people in this world, those who look at a problem as a hurdle and those who look at it as a wall.

 

[butlen]

Taking note of your plant details the following comments are obvious:-

1) 40,000 tonnes x £5/tonne = cost £200,000 per year
2) As you are quoting £ sterling per tonne I assume you are in the UK.

I would guess that CO2 scrubbing will cost a lot more than £200k.

CO2 scrubbing on this size and type of plant sounds a bit technically and commercially dodgy to me.

What will you do with your "scrubbed" CO2 (sorry if this is a silly question)?

I would buy CO2 credits for a couple of years (to wait and see what happens with carbon trading in the UK and European schemes), or alternatively look at other plants in your Group where it is easier or cheaper to reduce emissions than it is on this one.

Current market rate for a tonne of CO2 is £1.70 to £2.00 per tonne sterling.

Sorry its not much of an engineering answer, but like others I question the reason for you being asked to look at this.

Neil