Making biofuels from the papermaking industry's black liquor waste
Filed under: Emerging Technologies, Coal to Liquid
Sometimes, people just need to make the best with what they have got to work with. This is what paper mills are trying to do by burning the "black liquor" waste which is a leftover remnant of chemicals and the lignin. As part of the Kraft process (.pdf link), the leftovers are burned to create steam which turns large generators, which in turn provide electricity for the plant. In fact, enough electricity is generated that they can feed some back into the grid. This Kraft process is used for about 80% of all paper made. But what if there was a better way to generate power than by burning the black liquor for steam generators?
According to Andre Boehman, professor of fuel science at Penn State, "Black liquor is routinely burned in a recovery boiler, but it has more energy value as a synthesis gas which is then used to create other fuels." The researchers are suggesting that the black liquor instead be turned into a syngas and then into DME or dimethyl ether.
Diesel engines can be configured to run on DME, and Penn State actually has a staff shuttle which runs on the fuel. The researchers found that by adding a coal slurry to the black liquor and processing it into the DME, as opposed to using the Fischer Tropsch method, is the right way to use the waste. The researchers further say that DME is close to gasoline in efficiency, but not quite there. But, the black liquor/coal slurry process that they are suggesting would reduce greenhouse gas emissions much more than if only coal were used to make DME. Since the U.S. has so much coal available, until the country is truly weaned off our current power sources, we should clean them up as much as possible. As much as we would all love to see that coal stay in the ground, realistically we know how unlikely that is to happen. For now, let's use it as cleanly as possible.
[Source: Penn State]
Chevy Volt's gas tank gets downsized, range drops 300 miles
Rendered Speculation: 2010 Toyota Prius
Production Volt could be the guest of honor at GM Centennial party!
Next-gen Prius to get solar panel to drive accessories
Is Tesla using Dodge Magnum body shells for White Star mules?
Autoblog Green Podcast #24
Popular Mechanics to debunk the "run your car on water" myth
T. Boone Pickens unveils "The Plan" - big on wind power and natural gas
Reader Comments (Page 1 of 1)
8-23-2007 @ 9:57AM
Tim said...
So, they are ALREADY using the black liquor to produce electricity?
Then it's NOT wasted!!!
It would be a waste to use more energy trying to turn it into another product to power something else. http://en.wikipedia.org/wiki/Diminishing_returns
Reply
9-05-2007 @ 12:13PM
howard said...
In 1969 I was invited to witness a new process a man named VESSALS of Sherman Texas had developed for the GASSIFICATION of coal! I was invited be cause I was in the ELECTRIC VEHICLE business at the time! As about 50 people watched Mr. VESSELS opened a door an a large cylinder and deposited one pound of coal ( I'm not sure which grade)on a flat pan. Under the pan were three small containers that he said would catch any liquid that was squeezed out of the coal! not being an engineer all I could do was look on in amazement. He shut and locked the door and started a big vacuum pump and as we watched he removed all the air from that cylinder. The vacuum gage on the cylinder showed 32 inches of vacuum and as we sat there drinking coffee or soft drinks it held that for one and a half hours. Because the system was tight it never lost 1 inch of vacuum! After another hour he opened a valve very slowly and let the pressure build up in the cylinder then opened the door! Setting where the pound of coal was put was a pile of yellow looking powder, he told us that was sulphur, the last by product after the coal has been GASIFIED, in each of the small containers was a little liquid, he said one was raw gasoline which he lit a match to, the other is Diesel which he said wouldn't burn but passed it around for everyone to smell, it was diesel! There was one other small container that he took out and let some of us stick our finger in and taste it, it was water! Needless to say we all signed a NON DISCLOSER paper and were sworn to secrecy! I'm sure the time has run out for keeping this quiet so I'm now telling about the experience!
Reply
9-17-2007 @ 8:46AM
Judester said...
Black liquor used in paper plants to fuel their plants is from the process of making paper. After the impurities are burned off in the recovery boiler it is called white liquor and is piped back to the process of making the paper. It's quite efficient being used both in the process of making the paper and fueling the plant in both electrical and heating.
Reply