Sally Brown

May 1, 2018 | General

Connections: Recycled Paper’s Fuel Potential

Sally Brown

Sally Brown
BioCycle May 2018

I get a queasy feeling these days when I take out the recycling. I know demand for my aluminum cans is riding high, but I rarely have any of those. In contrast, demand for my paper and plastic is in the toilet. Cities in Washington State and on the West Coast are paying steep prices to have someone take them away. If I admit to myself where these materials are going, that gets me past queasy to downright disgusted. Ignorance in this case is bliss — my neighbors continue to be happy recyclers, taking full advantage of the blue bins that accept our mixed glass, paper, metal and plastic.
My queasiness stems from my knowledge of the National Sword policy in China. This policy severely limits imports of recycled paper and plastics in order to improve environmental quality in that country. One could argue that appropriate and enforced air and water quality regulations would have had a bigger impact, but that is a different column. China’s ban took effect on January 1, 2018, long before the proposed trade war was even mentioned. Farmers in the Midwest are nervous about the impact of the trade war to their bottom line and for good reason. In 2016, the U.S. sold $21 billion of agricultural products to the Chinese. Also listed in our top exports are aircraft, machinery and vehicles.
Coming in sixth on the list was recycled paper. Last year, the U.S. sent 13.2 million tons of used paper to China. While there is talk of a plan to bail out the farmers hit by this trade war, I would wager that no effort will be made to bail out the municipalities. If you think your desk is piled high with mountains of paper, check out your local MRF. The paper is piling up and landfills are becoming the destination of desperation.
My home state (Washington) has been hit hard by this policy, which in effect is a ban (even though it is not technically one). It has set standards for the level of contaminants and the quality of the recycled paper high enough that it is pretty much a ban. To meet these requirements, the one bin system that we are so attached to would have to be replaced by multiple bins and additional sorting post collection. The net result is that cities are now paying hauling services large sums to take their paper with most of that paper heading to the landfill. Tacoma (WA), for example, is paying over $25/ton to have the paper sorted and then an additional $50 (cardboard) to $120 (mixed paper) to have the material taken away. This is not a good business model.
There have been attempts to find other international markets for the paper. Vietnam took a few tons but quickly stopped accepting shipments. The volume of material was too high and the country’s ability to process it was overwhelmed pretty quickly. Other countries might step up but it is not clear that they would ever be able to maintain the volume that we had come to rely on with China.

Pulp And Paper Trends

So what to do with those piles? Understanding trends in pulp and paper is critical to making an informed decision. For that I talked to Rick Gustafson, a Professor in my department at the University of Washington (College of Forest Resources). His email is pulp@uw, which should tell you something about his interests and areas of expertise. It turns out that the market for most of the traditional uses of paper — for printing including office paper and newsprint — has tanked. People tweet and Instagram. Even if they read the paper they read it just the way I do: online.
The two markets that are strong are tissues and packaging. The tissue market includes all paper used for wiping — your nose, your behind and your counter. The packaging market is also strong thanks to companies like Amazon. Here the market has changed over time with synthetic fibers often used for small packages. But cardboard boxes are often chosen over synthetic packaging because of the higher strength and the structural stability of the cardboard.
Where does recycled paper fit in? Rule of thumb is that as the recycled content increases, the strength of the final product decreases. Another rule of thumb is that people like to wipe in white. For whatever reason, people don’t like to use brown paper. Food packaging — another use of cardboard — is also highly restrictive to protect food safety. That means limited potential for use of recycled papers for tissue, almost no potential for food packaging, and some potential for cardboard.
Cardboard boxes are a three-ply structure with two strong paperboard sheets held apart with a much weaker corrugated medium. Recycled fiber can be used in the corrugated medium but putting too much in the linerboard can severely weaken the box. What this means is limited potential for use of recycled paper for paper markets in the U.S. This is a result of the downturn in paper markets, and properties of paper products produced with recycled content.

Fuel Potential

Here is where other options fit in. Rick’s career arc can provide a guide. He made the switch from paper to fuel (bioresource-based energy) a few years back. His team at UW got a gigantic grant to develop fuels and chemicals from wood waste — and they did. I asked Rick about the potential for recycled paper as a feedstock for fuels. Direct combustion is a possibility but biomass for combustion is not a strong market. The market for pellets is strong in Europe and weak in the U.S.
What got Rick excited, and has enormous potential, is use of recycled paper for production of ethanol or higher value molecules such as lactic acid. According to Rick, it would be straight forward to transform recycled paper — of every color — into ethanol. Increasing the ethanol percentage in gasoline would also be fine. He said that 15 percent is not an issue for most cars, and that automakers believe that running cars on high ethanol content fuel would enable use of higher engine compression and better fuel efficiency. Rick added, with the caveat that this estimate builds in a lot of assumptions, that a price point of about $40 or less/ton would be needed to make this pencil out. That is what the ethanol manufacturers would pay for the feedstocks, not what the cities would have to pay for the plants to take it. To understand the potential here it helps to understand the basics of making paper and making ethanol.
Paper is typically made from wood. Wood is mostly made up of lignin and cellulose. Getting the lignin out is a key step in making wood into paper. A range of chemical processes do this, with the most common being the Kraft process, which involves adding two sodium compounds to the wood. The compounds separate the lignin from the cellulose and generate enough heat to power the process. It is the cellulose fibers that you want for the paper. Recycled paper consists mostly of cellulose and hemicellulose.
Now look at the process of making ethanol from cellulosic feedstocks — meaning materials high in cellulose. Here a key step is converting the cellulose into sugars that are then converted into ethanol. If you start with wood, the first thing you have to do is get rid of the lignin. Get it? By using recycled paper instead of wood you are starting with material that is already partially processed. Ergo, it is easier and cheaper to make ethanol from recycled paper than it is from wood. Using virgin feedstocks to make biofuels requires more processing than substituting waste paper would. In addition to the lignin, the virgin materials have phytochemicals that can hurt the process and may need to be removed. Recycled paper is also easier to break down and ferment into ethanol than fresh material.
Rick pointed out that the lignin content of virgin material generates the steam for the first stage of the process. In his mind, that was the sole drawback of using recycled materials. He noted that recycled paper-based ethanol would likely rate high as a renewable fuel and provide a wonderful carbon balance. We might even think about building some of those plants close to cities. It would also be a wonderful way to solve a paper crisis. It is not an instant solution but could provide a local, high value end use for these materials — one that requires no Pepto Bismol to settle my stomach and instead leaves me with a smile on my face and fuel for my tank.
Sally Brown is a Research Associate Professor at the University of Washington in Seattle and a member of BioCycle’s Editorial Board.

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