Grass instead of oil
- Grass or straw will in the future become degradable plastic cups.
The resources of the future will come from biorefineries, They combine the material and energetic uses of biomass in a highly efficient manner. What to expect from technology in the post-oil era.
By martin Bensmann and Dirk Jensen, Photo: Pauul-Langrock.de
So it was no flash in the pan after all: In mid-February prices for a barrel (159 litres) of crude oil again exceeded USD 100. Expert prognoses see the prices in five to 10 years at even 150 to 200 dollars a barrel. It’s a development that will have substantial consequences for the world economy. The sooner oil can be replaced, the better.
The situation in Germany looks like this: In 2006 about 113 million tonnes of oil were used. Almost 53 million tonnes were consumed by diesel and petrol vehicles. Heavy and light heating oil accounted for about 33 million tonnes, more than 10% was used for chemical material products. So how to replace these amounts?
Biomass would be an alternative. But often it is erroneously regarded only as a potential energy source. Yet with a rate of 30% biomass is low-efficiency fuel. Used for heating it achieves 95% efficiency. For Germany’s industrial competitiveness it is essential to develop alternative raw material sources. In organic chemistry, for example, about 88% of the raw materials are produced on the basis of crude oil. The German chemical industry now processes merely two million tonnes of biomass per year, corresponding to 10% of its raw material needs. This is where the future challenges lie.
Chemistry and energy duet
Proteins from grass, plastics from starch, natural lactic and amino acids for the food and non-food sectors are already in products used in everyday life. There are biologically degradable packaging materials, garbage bags and disposable dishes. That is a first step.
But biomass is not limitlessly available. Growing demand for energy and material uses and the competition with food production are making higher efficiencies imperative. So what does optimal use of natural resources look like? Biorefineries could be the solution. They process the biological raw materials into a great number of valuable products (see box). Thus carbohydrates and vegetable oils are turned into soap, cosmetics, soap power and cleaning agents. Oils, starch and sweeteners flow into the food chain, fuels are produced for mobility and important basic materials like lactic and acetic acids for the chemical industry. In combination with a biogas or pyrolysis plant remnant materials are used for energy production or transformed into a new energy source such as biogas. In other words, biomass is both a raw material supply and an energy source.
The basic principle of a biorefinery is old hat. Potato starch and sugar factories, biodiesel and ethanol plants are fundamentally no different. Their by-products such as mash and glycerine are used industrially. Some already combine their production plants with biogas installations, such as the potato starch factory of Emsland-Stärke GmbH in Wietzendorf, about 90 km south of Hamburg. There the potato pulp and liquid leftovers are fed into the fermenter. Verbio in Zörbig also wants to install a biogas plant based on the ethanol process chain.
The primary purpose of the existing plants is to produce one product, biofuels. As the name by-products suggests, all other substances are more or less ancillary. The difference in the biorefinery concept is to convert the raw material as optimally as possible into as many products as possible. The material use is likely to take priority over the energy use.
Lactic acid from grain
A large number of scientists are researching the most varied procedures around the world (see pages 72 and 76). Pilot plants are working or being planned in Germany. One demonstration plant is located, for example, on the grounds of the Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB). It has an annual capacity of 10 tonnes of lactic acid. “We have been producing lactic acid from rye for a year and a half,” explains Joachim Venus, of the bioengineering department at ATB. “We glean about 100 litres of highly pure lactic acid from one tonne of rye.” Additionally, product samples leave the trial reactor in response to specialised demands from the most varied customers.
Residues that cannot be used to produce lactic acid can be used as stock fodder because they are rich in proteins and minerals. Apart from producing materials of value, the pilot plant captures data for the scaled up application in a large plant. The scientists are also pursuing model solutions for integration in sustainable holistic concepts for material and energy use of agricultural raw materials. The Potsdam pilot plant cost EUR 3.2 million. EUR 2.4 million came from the European Regional Development Fund, the German federal and state governments shared the remainder with 12.5% each. There is growing demand for the Potsdamers’ core product.
The Agency for Renewable Resources (FNR) in Gülzow estimates the future European market volume for pure lactic acid at about 100,000 tonnes annually. To produce it the industry would need about 40,000 hectares of wheat, corresponding to about 0.3% of the German field area. In 2006 wheat was grown in Germany on about 3.1 million hectares.
Combining glycerine and biogas
Money from Brussels also flows to the Hamburg University of Technology (TUHH). Since the start of the year it has coordinated a new three-year EU project for sustainable production of new materials from glycerine, without residues and with the lowest possible energy consumption. The EU is allocating two million euros to the project from the energy section of its seventh framework programme for research and technological development. Glycerine, for example, is a 10% by-product in making biodiesel from rapeseed oil. Related to the amount of biodiesel produced in Germany last year, about 300,000 tonnes of glycerine must have left the factories. This volume was processed in the chemical and pharmaceutical industries. But biogas plants have also discovered glycerine and fermented it to produce power.
From glycerine, so-called 1,3-propanediol can be extracted, which is especially suited to the production of car paints, carpets and textiles. But because only some of the glycerine will convert into 1,3-propanediol and the process currently needs a lot of water and energy, An-Ping Zeng, head of the international research group is looking for more efficient and sustainable processes. In the ideal case, there will be no residues in future if additionally energy in the form of biogas and fertiliser are won simultaneously. In a bioreactor in laboratory dimensions Zeng intends to use a microbial community to that end. That means two or more bacteria which in nature avoid one another, such as clostrides and methanosarcina, are brought together.
Great expectations in common meadow grass
A pilot plant of a completely different kind is to be built soon in Selbelang, 85 km west of Berlin, near an existing forage drying plant and a biogas installation. This is a so-called “greenery biorefinery”. It uses the growth on permanent pasture, land taken out of production and nature protection areas or field crops such as lucerne, clover and unripe grain. Analogous to a petroleum refinery, the raw material available in large quantity and sustainably producable in agriculture is to be processed in just one plant as completely as possible and without waste into a variety of sellable product groups.
“At the moment we’re waiting for funding approval,” reports Professor Birgit Kamm of the biorefinery competency centre at the Teltow-Seehof research location near Berlin. At the start, the plant is to consume 8,000 tonnes of green biomass a year. “The existing drying plant supplies the pressed sap from which the biorefinery will extract proteins as well as lactic and amino acids. The high-grade proteins can be used, for example, for cosmetic articles or food supplements,” Kamm says.
In the first stage of the refinery to be built the pressed biomass residue is to be used as animal feed. Later the biochemists are to convert it into a building material, for example insulation padding. In the biogas plant it could supply biomethane which in turn could deliver process energy.
Such concepts are not likely to fail for lack of materials. Germany has around five million hectares of grassland. With ever less being used for dairy and beef cattle, the FNR sees about a million hectares available for material and energy usage in the medium term. At this point it is unknown on what scale this land will be used for the one or other activity or in combination.
Green biorefineries are of interest not only in eastern Germany. In the northwest, too, where grassland is no longer used agriculturally, farmer representatives are looking for alternative ways to gain value from it. “We’re just now designing a project in which we want to show best practice examples. Farmers already operating a small biogas plant want to start with small refineries,” reports Reent Martens, project manager of the Lower Saxony Renewable Raw Materials Network, 3N, in Werlte, 100 km west of Bremen. He says the project is international, also involving The Netherlands, Belgium, Sweden and the United Kingdom. Intensive research into the biochemical use of biomass is being done at the Dutch university of Wageningen, about 90 km southeast of Amsterdam. An interesting raw material in Holland, for example, are flower bulbs left in the ground after cut flowers are harvested. “There are enormous quantities of them and because of their acrid contents they can’t be used directly in biogas plants. They would retard the biological process,” says Martens. But the ingredients might be of interest to the pharmaceutical industry. Now the bulbs stay in the soil and rot.
First pilot project in Austria
Initiators of a project in Upper Austria are a step further than Germany. In Utzenaich, 250 km west of Vienna, work began in March on a green biorefinery beside an existing 500-kilowatt biogas plant of the Ökoenergie Utzenaich fi rm. It’s to start up in the autumn. “It is a joint project of the state of Upper Austria, the federation, Energie AG, Linz AG, Rohöl-Aufsuchungs AG (RAG) and the Upper Austrian Ferngas AG,” reports Stefan Kromus, CEO of Biorefinery Systems. Three to three and a half million euros is to be invested.
Together with Joanneum Research in Graz his enterprise has developed the technology for the demonstration plant. The two have cooperated on the development of the processes for seven years under the Austrian research programme, “Factory of the future”. A special feature is that the refi nery is to run continuously throughout the year. It will process not just fresh meadow grass, as planned in east Germany, but also grass silage.
Depending on future milk production, first estimates by experts see 250,000 to 500,000 hectares of grassland available in Austria. The country imports about 770 tonnes of lactic acid per year. The market potential is estimated at about 15,000 tonnes a year. According to Kromus the pilot plant can deliver five tonnes of green mass for the process per hour. Per hour it produces one kilogram of lactic or amino acid.
The biogas plant at the location takes in the press cake and delivers the process energy needed. The energy yield of the press cake is comparable with that of grass silage. Because the biogas plant delivers more than four million kilowatt-hours of thermal energy a year, any amount of heat is left over after own needs and those of the pilot plant have been met. The operators use it to dry maize, other grain and wood chips.
Austria has a rule that all heat emitted must be used. With some of the residual heat the biogas producers dry the solid material pressed from the fermentation residue with a belt drier. One use for the dried solid material is as fuel. It could also be used to make synthesis gas for biofuel production. The process known as Fischer-Tropsch synthesis, named after its German inventors Franz Fischer and Hans Tropsch, would suit. Companies like Choren have worked for some time on refining this technology to extract fuels from solid biomass. But it is likely to be several years yet before what is being called the second biofuel generation gathers momentum. That is, if certain processes are not dropped again for reasons of cost and efficiency.
For Choren and others like them are getting competition that doesn’t use chemistry, but microbiology. We’re talking here about enzymatic pulping of lignocellulose, i.e. the fibrous, woody parts of plants. “When cars run on straw and branches” was the heading on a recent article in the Frankfurter Allgemeine Zeitung newspaper and which described the technique used by Professor Eckhard Boles to convert cellulose into alcohol by employing genetically modified yeast strains.
Yeast crack cellulose
With complex genetic engineering interventions the bioscientist and his team at the Institute for Molecular Bio Sciences of Frankfurt University have created a yeast type able to ferment into ethanol glucose, xylose (wood sugar) and arabinose (a white crystalline aldose sugar occurring especially in vegetable gums) – which covers most of the long-chain sugars contained in plant wastes. What has worked so far in the laboratory is soon to be put into practice on a large scale. “We aim to be producing with a larger pilot plant in two and a half years,” says Gunter Festel of the start-up firm Butalco, based in Huenenberg in the Swiss canton Zug. Festel, a chemist and economist, and Boles launched the company in August 2007. “A year after that we intend to be producing commercially,” Festel, who is also founder of the Swiss consulting and investment company, Festel Capital, is confident. Patents for the genetically manipulated yeasts, which can crack C5 sugar into simple sugar, have already been applied for. In the meantime a northern German wind park project developer, Volkswind GmbH based in Ganderkesee, has become involved in the project, investing a six to seven-digit sum.
He sees no critical debate ahead about the genetic manipulation of the yeast. “I don’t think so because we are operating in a closed circuit far removed from the food sector.” Interestingly, in the short and medium terms Festel wants to source the raw material regionally from field crops. But he believes that in the long term the biomass will be sourced from forest stocks. The Butalco process could deliver 15 to 20 per cent of the German petrol demand.
“Use of forest wood has reached the limit,” warns Yasmin Murn, a forest information technologist at the University of Applied Sciences Eberswalde, located 70 km northeast of Berlin, which describes itself as dedicated to the sustainable development of rural areas. Murn coordinates Dendrom, a collaborative project funded by the German research ministry, which addresses sustainable usage strategies of dendromass, i.e. biomass from wood.
In Murn’s estimation forests are already being over-planned by several fold for both material and energy uses. She says just one example of the growing pressure is that branches less than 10 centimetres thick used to stay in the forest to rot, whereas “now all branch material down to a thickness of four centimetres is used”. She cites a rethinking in forest management. “Forest stock is being managed more and more optimally.” But Murn regards a sustainable biofuel quota of 20% as “very ambitious”.
An example of the optimisation trend is provided by the Scandinavian paper giant, Stora Enso. The huge consumer of wood is looking into more efficient usage of the biogenous residues. “In the company we’ve been thinking for some time about engaging more strongly in the bioenergy segment,” says their Jussi Koch. That does not mean, though, that Stora Enso will neglect its core business of producing pulp and paper, he adds. “We don’t want to nor can become Shell,” Koch continues, “we process plant fibres.” A by-product is lignin, which constitutes about half of the raw material. The paper producers remove it from the wood and burn it to produce power and heat in their own plants. This is why generally the cellulose and paper makers produce about half of their energy requirements with bioenergy, which is a very high proportion.
Setting clear priorities for the future
Karin Arnold at the Wuppertal Institute for Climate, Environment and Energy is highly enthusiastic about efforts to raise efficiency. “Save, save, save,” is her mantra. Arnold argues for intelligent multiple usage of biomass. She calls the basic principle cascading: every biomass should first run through a meaningful material life cycle before it is used to produce energy. The scientist also sees completely new material-energetic usage patterns which give equal ranking to value creation and ecology. “We’re going to have to address that very intensively in the coming years,” she says. She gives an example: “No one now wants straw.” She puts the usable straw volume just in North-Rhine Westphalia, Germany’s most populous and fourth-largest state, at about 470,000 tonnes per year. “That’s quite something, especially considering that straw is a by-product of grain production and therefore doesn’t clash with food production.” Perhaps it could be one of the raw materials on which the yeast strains à la Butalco and other entrepreneurs will feed in future?
But caution: Not all straw is usable for material or energy use. A considerable proportion has to stay on the fields as organic mass for humus reproduction. Moreover, voluminous straw bales have low weight so that transportation to processors is restrictive.
A traditional example of the successful use of natural raw materials to substitute for petroleum is caoutchouc. The proportion of natural caoutchouc in rubber compounds for tyres has increased in recent years in relation to synthetic caoutchouc based on petroleum. After a tree life of about 40 years, a co-product of the caoutchouc plantations is timber for furniture.
Chemical industry cautiously optimistic
Switching from petroleum to biomass is not going to be easy. To facilitate it, the “chemistry” first has to be right between the processing industry and the proponents of renewable raw materials. For example, chemical giant BASF in Ludwigshafen doesn’t believe largescale transformation of its production to biomass is possible in the mid term. The most important base materials for German industry are now olefins and aromatic compounds, produced mainly by cracking and reforming of benzine (naphtha), the company says. “The raw material conversion projects form one growth cluster of five in the BASF research programme,” says Rainer Diercks, head of BASF‘s Chemicals Research and Engineering division.
“In the raw material conversion cluster experts identify interesting processes for using alternative raw materials and evaluate them by technological, economic and ecological criteria.” Diercks says about EUR 100 million are available for research between 2006 and 2008.
BASF is staying focussed on conventional fossil resources. Diercks emphasises that mainly natural gas and possibly coal come under consideration as additional ones for now. Gas could help out initially, he opines, but its price depends on the oil price. Coal will be available a lot longer and is now relatively competitive, he says. But this solid material poses high technical demands, he notes “and the carbon dioxide balance has to be improved.”
“The future challenge is access to low-cost fermentation resources,” suggests the research chief. Alongside glucose, glycerine, a byproduct of biodiesel production, is a possibility in the short term, he says. “As a long-term solution we’re evaluating the use of cellulose from biomass such as plant waste, Diercks adds. With its presence of about 700 billion tonnes cellulose is the world’s biggest organic raw material source, he notes. Of the 40 billion tonnes forming annually, only 200 million are used. A research partnership between BASF and the University of Alabama will study the dissolution and processing of cellulose through use of ionic liquids, enabling a direct dissolution process to produce products such as cellulose fibres and plastic sheets.
Even though the chemical industry is flirting with various options, if enterprises want to source efficient and low-cost raw materials long-term they won’t be able to ignore the biorefinery concept. The grass age has begun.
Not milk, but an insulation material
“We’re cautious,” says Michael Gass, CEO of Biowert Industrie GmbH, founded in 2005 as a subsidiary of Biowert AG in Aarau. “Biorefinery sounds so highly sophisticated,” Gass shrinks at the term. “We process grass.” Biowert converts ordinary meadow grass into insulation materials and plastic filled with natural fibres in the first plant in Brensbach, 65 km south of Frankfurt on Main. Later integrated separation of valuable amino acids for the pharmaceutical and food industries (aromas) is to follow. In a neighbouring biogas plant with two combined heat and power generation stations of 700 kW electric capacity each the liquid substrate remnants are fermented together with other bio wastes to produce power and heat. The heat is used directly in the fibre production process. For the time being, the last cascade of the grass processor is the nutrient-rich fermentation residue; in the long term it is to be sold as commercial fertiliser.
Biowert invested about EUR 5 million and has produced since summer 2007. Five thousand tonnes of grass per year from the surroundings are fed into the silos, then into the wash, are stirred into a thick soup and mixed with borate. Then the substrate is mechanically treated. In the end the woody fibre separates out and is processed into loose insulation material. The pourable material is usable in roofs, attics and walls as a heat insulator and was on the list of natural insulation materials promoted as part of a market introduction programme run by the Agency for Renewable Resources of the Ministry of Food, Agriculture and Consumer Protection.
“Biowert is the furthest along in industrial implementation, automation and process technology,” says Gass. But he still sees a long way to go to the biorefinery for himself and his colleagues, especially as the concept of Brensbach is very regionally designed and the input-output stream is driven by the idea of circular economy. Enzymatic pulping of the fibre parts is not economically viable with an annual throughput of 5,000 tonnes, argues Gass. That is one of the main reasons for his choice of process. Anything else would be barking up the wrong tree, he quips.
Millions for US biorefineries
An enormous amount of money is being spent on biorefinery research in the United States (see page 76). At the end of January the US Department of Energy announced USD 114 million (EUR 78.6 million) support for four smallish biorefinery projects up to 2010. The projects are to run in Wisconsin, Missouri, Oregon and Colorado.
The biorefineries are dimensioned 90% smaller than future industrial-scale plants. The daily biomass throughput of the demonstration plants is about 70 tonnes, amounting to an annual output of about 9,500 tonnes of fuel.
More pilot plants are to receive promotion funding in the spring. The financial volume from the responsible ministry will rise to USD 138 million. In addition to the production of cellulose ethanol, biochemicals and bioproducts for industrial applications are to be produced.