Stanlsimon;
From what I can deduce of your basic data, you are trying to do a complete, natural energy cycle where you harvest organic growth (wood), “gasify” the wood to a methane-rich fuel (by some unknown process), burn the resultant fuel gas in an internal combustion engine that drives an electric generator and emits a CO2-rich exhaust. The resultant exhaust would be processed to remove the CO2 and return it to a green house to supply the needed carbon to produce an organic growth (trees?). Although you don’t state as such, this sounds like an agricultural perpetual motion machine. Organic growth produces energy, CO2, and more organic growth – with some fertilizer, water, and a lot of labor.
I’m not into agriculture, but I’ve been into a lot of CO2 – generated from combustion products, recovered from chemical processes, and recovered from natural CO2 wells. I’ve spent a lot of years in design and operation of CO2 recovery plants. I don’t believe your proposed process has a practical chance of succeeding but I think it’s only fair to give you the benefit of the doubt. However, my years of experience confirms what both Dave Simpson and dcasto are stating and alerting you to: beware of the exhaust gas process conditions and prepare for an expensive piping and handling installation just to transport and handle exhaust gas. The MEA purification system should be a piece of cake. The MEA process has been around since Mr. R. R. Bottoms patented it in 1935 for the Girdler Corporation. Since then, quite a lot of Lessons Learned and other improvements have made it a pretty easy application to employ. The main tradeoff is the same as it was in 1935: the reboiler duty requirements are high for regenerating the rich MEA into lean MEA. This feature alone has scuttled many countless other CO2 recovery projects in the past – many of them based on flue gas from electric generating stations.
Contrary to what you state, Monoethanolamine (MEA) is NOT CORROSIVE. In fact, for many years it was known and employed as a corrosion deterrent and inhibitor. Please don’t interpret my factual statement as a criticism against your proposal or statements. My purpose here is merely to state factual information that is backed up by historical field experience and findings. While MEA is not a corrosive chemical, its oxidation products and other side chemicals produced by its degradation through excess heating and combinations with other chemicals do, indeed, produce bad corrosion. An MEA solution with strength of up to 20% MEA can be controlled and maintained in a non-corrosive state by filtering with activated carbon and applying a re-distillation still to the MEA circuit. This is commonly done in almost all successful MEA process units operating today. I have operated plants with up to 18% MEA with only the hot Rich MEA tubes in the MEA exchangers and the tubes in the steam-heated reboiler being constructed of stainless steel. All the remainder of the process was fabricated of mild carbon steel – mainly A-212 or A-516. And I experienced no detectable corrosion – as long as the activated carbon filter and the redistillation still were operating normally. You certainly do not need “exotic steel” to handle MEA solutions up to 18% strength. However, if you don’t know any better or don’t want to maintain a clean and pure MEA solution, you are certainly free to use any expensive exotic alloy if you so desire.
I hope this experience is of some help.