8B. Wood Synthetic Natural Gas Allam Cycle BECCS Power Plant
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8. Allam Cycle     8b. Allam Plant     8c. Allam Cycle vs. Conventional BioEnergy + Carbon Capture & Storage (BECCS)


Wood Synthetic Natural Gas Allam Cycle BECCS Power Plant
(Shown with already developed coal syngasifier as a possible beginning prototype to build off) 
(The largest biomass gasifiers seem to be 1,000 ton-per-day wet MSW (Metropolitan Solid Waste [domestic garbage]) plasma torch gasifiers for providing gas to sub-100 megaWatt electricity generating turbines.)
(Over 100 mW we find boatloads of U.S. wood pellets recently replacing pulverized coal in European power plant boiler installations.)
(At the moment, it looks like I would have to use several 1,000 ton-per-day plasma units for base load and supplement them with natural gas for peaks.)
Midwest Regional Carbon Sequestration Partnership: 

(NOTE: "LHV" means lower heating value, "HHV" means higher heating value. Coal and lignite might come out this way because of their different starting heat values.)

Allam cycle is natural gas-only. Solid fuels such as wood need a solid-to-gas gasification module. 

(If we can figure out how to make money at it.)




Please take a look at the youtube video presentations listed below. You can't get easier-to-understand presentations faster. And very few commercials.

     The company:     
     Articles About:             supercritical carbon dioxide (sCO2) cycles
     This website's pages:  3a Natural Gas or Oil Allam Cycle CCS Power Plant          3b Coal or Lignite Allam Cycle CCS Power Plant          Similar Technologies

This new type of power plant, located over a CO2 disposal region, would burn trees originally planted to remove Climate Change CO2 from the air, store their CO2 underground, and sell the electricity.




The basic Natural Gas burning Allam cycle module.
"ASU" means "Air Separation Unit". The ASU contributes oxygen from the air to the CO2 working fluid for combusting the natural gas in CO2 (1). First time I've encountered this.
To me, it's basically a rocket engine connected directly to a single stage steam turbine. The CO2 and steam water are then separated in (4), the water separator.
Most of the exhaust of a rocket is steam - recall all the white?



For details of proposed coal processing components see pdf 2.306.02

A leading chemical engineer, Rodney Allam, has invented a new fossil-fuel powered thermodynamic cycle for power plants. It has been named the "Allam Cycle".  It's emissions are sequestration grade and pressure CO2, potable water, industrial grade argon gas, and industrial grade nitrogen gas - each coming out of their individual exhaust pipes.  A 1/10th size pilot plant has been constructed in LaPorte, Texas (near Houston) and has been connected to the Texas electrical grid, providing 25 megaWatts of electricity since last October. As far as I know, so far, so good.

This new technology has the potential of economically powering the reduction of fossil fuel greenhouse gas emissions to net-zero by 2050 by powering the manufacture of biomass-based net-zero replacements for fossil fuels such as gasoline, diesel, jet fuel, and natural gas. Since fossil fuel is available everywhere, these fuel factories can be located anywhere both biomass and CO2 sequestration strata exist. Mankind can then consume the world's remaining fossil fuel by using it to power the manufacture of net-zero fossil fuel substitutes.

Dubbed the "Allam Cycle", it exploits the thermal and pressure characteristics of supercritical liquid carbon dioxide and water - instead of pure steam, air, or helium - as its working fluid. Relatively simple and 59% efficient, it uses an external rocket-engine-like oxygen+methane combustor instead of a water boiler. The combustor directly drives a simple high-temperature gas turbine-generator with a blast of CO2 gas and steam. It can be powered by any methane-gasified fossil fuel, i.e., natural gas, oil, coal, lignite. The only emissions are pure high pressure liquid CO2 ready for underground disposal and pure liquid fresh water, industrial grade nitrogen gas, and industrial grade argon gas, each coming out of the Allam engine contained in it's own pipe. If renewable fuels are used and sequestered, the Allam engine would produce carbon-negative CO2 emissions.

It should be noted that the super-clean, fossil fuel versatile, Allam Cycle 30 mW(e) grid-connected pilot plant - a new form of Oxy-fuel carbon capture - is performing well and appears economically competitive all the way down to non-CCS Lignite.

The first mass production Allam cycle power plant will be a 300 mW(e) single turbine version made by Toshiba, possibly as soon as 2021. "While the challenges remain significant and require a focused research effort, there donít appear to be any show stopping problems to commercialization of this technology." - P.A. Strakey, et al., 2014. 

Toshiba will manufacture the 300 megaWatt full size version. In addition to the 300 megaWatts of grid electricity, it might produce as much as 1 million gallons of potable water per day and 5% CO2 by volume. The Allam's oxyfuel combustor is pretty close to a rocket engine. Think of the massive white plume of steam coming out of a oxyfuel rocket engine as it lifts off.

Perhaps Toshiba could license their design to the world's top power plant companies to ultimately make 10 to 20 thousand 300 mW copies in the next 10 to 20 years. The coal and lignite versions would need an additional gasification module. Shutting down all the world's conventional coal plants would really pull the rug out from under Climate Change.

To this author, this achievement may open the door to halting the 100 million tons of CO2 the world adds to the air every day via unconfined fossil fuel burning and perhaps also halt most of the current plans for building over 1,600 new large conventional coal power plants in 62 countries    [Urgewald's tally], replacing conventional air polluting coal power plant plans with plans for environmentally safe Allam cycle gasified coal power plants instead. (Recall pre-WWII "Town Gas" made from coal?)

Once fossil fuel CO2 addition to the air is halted by substituting the use of environmentally safe carbon-neutral renewable fuels instead of fossil fuels, CO2 subtraction from the air can begin with the goal of eventually restoring the air to the way it was before the beginning of the first fossil fuel age.   




I've been aware of what power plant steam turbines should look like since 1956. This is the fattest turbine I've ever seen. Supercritical carbon dioxide must pack a heck of a wallop.
Look at all those bolts holding it together.  Unlike an ordinary power plant steam turbine, this one has an integral cooling jacket like a car engine.

A typical power plant turbine has three-stages of pressure: High, Medium, and Low. This unit has only a single stage and it's way small for the power it is putting out. A conventional turbine for this power is the size of a school bus, this turbine is the size of an SUV.  In fact, the Allam Cycle turbine is different from every turbine that has ever been built before. This turbine is a hybrid of both the gas technology turbine and steam technology turbine since it operates at the high temperature of the gas turbine and high pressure of the steam turbine. The carbon dioxide which is obtained from the lower temperature end of the plant is fed between the space of the inner casing and and outer casing to cool it and prevent the metal from reaching its metallurgical limits.









1. (In Case the Allam Cycle Idea Does Not Work Out or Fails to Gain Widespread Market Acceptance.)

Below: Similar BECCS-capable power plants  


You can strip about 5 barrels of "Stuck" oil per barrel of liquid CO2 from a "Depleted" stripper oil well by using liquid CO2 as a solvent to free it up.
While most of the liquid CO2 can be recovered when the dislodged oil is processed at the wellhead, eventually the CO2 becomes "Stuck" underground forever instead.

Around 2010, there were several supercritical CO2 engines in various stages of development out there in the Kimberlina, California, sand and bushes.
The Allam cycle engine appears to have captured both the technical and market leadership by 2018.
One place where Allam's thinking shows up is they used a really tough single-stage sCO2 steam turbine in their demonstration plant in La Porte, Texas.




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(The image above is from a different web site and will eventually be corrected.)





Why Wood?  The CO2 molecule is made of one carbon atom and 2 oxygen atoms. 1 Kg of carbon on complete combustion will produce 3.67 Kg. of CO2. Wood is heterogeneous and the exact amount of carbon in 1 Kg of dry wood will vary depending on the species of wood, age of wood etc.
1. It is reported that 1 Kg of wood contains about 450 to 500 gm of Carbon. This means 1 Kg of wood is holding about 1.65 to 1.80 Kg of CO2. This is how wood or forest act as carbon sink. Similarly, burning of 1 Kg of wood containing 500 gm of carbon will generate 1.65 to 1.80 Kg of CO2 and 17,070 btu of heat.
2. Heat from wood Synthetic Natural Gas (SNG) costs more than heat from natural gas but the 60% gas efficiency of the Allam Cycle power plant is almost twice that of a typical 35% efficient fossil natural gas power plant. European coal power plants are burning U.S. wood pellets to keep their CO2 emissions low.
3. Metropolitan Solid Waste (MSW) i.e., Garbage, is being used to make syngas to power small 50 megaWatt syngas power plants, worldwide to minimize landfill waste. Similar MSW syngas/SNG plants could add their outputs via short local gas mains to base power a large 300 megaWatt Allam Cycle plant.


Planet Earth currently has about 3 trillion trees and might support an additional trillion. (In the United States, a trillion is a thousand billion and a billion is a thousand million.)  It's essential we plant as many trees as possible immediately all over the world because we will need them for removing Climate Change from the air when the last of the fossil fuel decarbonizations has been completed and the installation and startup of the first several hundred Allam BECCS power plants has been completed. The Allam power plants will first be running on natural gas and coal converted to synthetic natural gas, switching over to wood BECCS mode as the wood gasification equipment is installed. This could be as soon as 2030 to 2040 so the first Climate Change removal trees would be only 20 years old at most. After that, perhaps an annual rotating crop of trees or equivalent energy plants such as switchgrass will be needed for over 100 years.
California has biomass electricity power plants that consume 1 ton (900 Kg) of woody biomass per hour for each megaWatt-hour of electricity produced.  So, a 300 megaWatt Allam BECCS power plant could consume as much as 24 hours x 300 tons or 7,200 tons of woody biomass per day. 
1 Kg of wood holds about 1.65 to 1.80 Kg of CO2. A 10-year old typical small tree weighs 1,800 to 4,500 Kg. 1 ppm CO2 = 2.12 Gtonne carbon or 7.76 Gtonne CO2. (IPCC and Gilbert Masters). 1 Tonne (a Metric Ton) = 1,000 kg. 1 G (Giga) = 1 Billion.
To remove enough CO2 from the air to go back to the end of the last Ice Age we would need to remove from the air: 415 ppm CO2 - 280 ppm CO2 = 135 ppm CO2.  135 ppm x 7.76 Gtonne CO2 or 1,047 Gtonne CO2 or about 1 trillion 2 ton trees.