ISSN 09655441, Petroleum Chemistry, 2010, Vol. 50, No. 4, pp. 298–304. © Pleiades Publishing, Ltd., 2010.

Petrochemicals: Raw Material Change from Fossil to Biomass?1 W. Keim Institute for Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, D52074 Aachen email: [email protected]aachen.de Received January 15, 2010

Abstract—The petrochemical industry, which is based on crude oil and natural gas, competes with the energy providing industry for the same fossil raw material, but uses only 10% of it. This leaves the energy providers in the driver seat and makes the petrochemical industry dependent on them. Dwindling oil and gas reserves, concern regarding the greenhouse effect (carbon dioxide emissions) and worldwide rising energy demand raise the question of the future availability of fossil raw materials. Biomass as a renewable resource appears as an alternative to substitute oil and gas. Current use of biomass for organic chemicals amounts to 10% and is mainly based on sugar, starch, fats and oils (first generation of biomass). The use of these raw materials brings the chemical industry also in competition with nutrition for man and animal. Great interest centers around the use of “nonfoodbiomass” (lignocellulose), which is available in nearly abundant amounts, but routes for chemical utilizations are lacking. Biotechnological, chemical and engineering solutions are needed for utilization of this second generation biorenewable based supply chain. One approach consists of the concept of a biorefinery. Also gasification followed by liquefaction is a promising pathway. Short and medium term a feedstock mix with crude oil and natural gas dominating can most likely be expected. Very long term, due to the final limited availability of oil and gas, biomass will prevail. Prior to this change to occur great research and developments efforts must be carried out to have the necessary technology available when needed. DOI: 10.1134/S0965544110040079 1

1. INTRODUCTION

Nearly 90% of todays petrochemicals are based on crude oil and natural gas which, are converted to mainly five basic building blocks namely ethylene, propylene, C4derivatives, benzene and xylenes. These basic chemicals form the pillars of the whole petro chemical industry with its thousands of intermediates and final products. Worldwide only 10% of the crude oil is used for the manufacture of petrochemicals, 50% for transporta tion fuels, 20% for heating and 20% for others. Obvi ously, the energetic and material use of crude oil is closely linked whereas the energetic use by far is dom inating. This creates a competitive market, which makes petrochemicals highly dependent on the refin ing industry, and the fate of the refining industry will govern the future of petrochemicals. The most impor tant question centers around the availability of mineral oil and gas in the future. Here estimates for the statis tical availability of fossil raw materials (“peaking oil and gas”) are: mineral oil 40–50 years, gas 60– 70 years, coal 150 years [1–5]. Also the production of carbondioxide, when using fossil raw materials, and rising energy demand due to population growth and higher energy consumption by countries like China 1 The article is published in the original.

and India, are alarming. In addition, fluctuating prices and security of supply provide great uncertainties. This situation gives rise to a growing interest in using renewable resources such as biomass for the pro duction of chemicals thus substituting crude oil and natural gas. In the past, many people have predicted this development and have demanded, that mineral oil and gas should be used only for material and not ener getic applications [6, 7]. Also the energy providing industry, for the same reasons, looks at alternatives as is shown in Fig. 1. Besides biomass, the organic chemical industry may look at coal and carbon dioxide for feedstocks. Historically, the use of biomass stands at the beginning of the chemical industry followed by coal and oil and gas. Without crude oil and gas the “polymer age” would not have been possible. Still today coal is used for special chemicals such as polyaromatics and heterocyclic compounds. Recently, coal derived PVC plants have been built in China. There are even speculations predicting a renaissance of coal chemistry. In Fig. 1 also CO2 is listed as a potential feedstock for the chemical industry. Today, small amounts of CO2 are used to make urea, methanol, cyclic carbon ates and others [8]. However, if inexpensive hydrogen would be available in sufficient amounts—for instance,

298

PETROCHEMICALS: RAW MATERIAL CHANGE FROM FOSSIL TO BIOMASS?

Alternative Raw Material

Alternative Raw Material

Resourees for the Organic

Resourees for Energy

Chemical Indastry

Prodaktion

Biomass

Biomass

Coal

CO2

CO2

Nuclear

299

Sun derived Geo thermic Moon Derived Fig. 1. Alternative raw material resources for the organic chemical industry and for energy production.

derived by nuclear or sun energy—CO2 could be hydrogenated to methanol, which could be an impor tant raw material [4, 5]. CO2 could be the feedstock of the third generation. Especially algae could be applied. In Fig. 1, also alternatives for the energy pro viding industry are listed. Also this industry looks at biomass as potential raw material, but harvesting the sun (water power, wind, voltaic, thermal) and nuclear offer greater carbon free (non fossil) potentials. 2. BIOMASS AS RAW MATERIAL [9, 10] The beginning of the chemical industry sees biom ass of animal and plant origin as raw material. Exam ples are: methanol, ethanol, acetic acid, acetone, pharmaceuticals, dyes, fibres, polymers. Today, about 10% (2 mio tons) of the German chemical industry is biomass derived. Table 1 exhibits the raw materials worldwide used. There are advantages and disadvantages using bio mass: • advantages renewable, CO2 neutral, clean, homegrown (secu rity of supply), potential for new products and pro cesses, job generation in rural areas, prices, synthesis of complicated molecules by nature • disadvantages low energy density (for energetic use), land requirements, harvest failures, soil exhaustion, mono cultures (biodiversity), deforestations, water require ments, ground water contamination, competition with nutrition PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010

2.1. Fats and Oils In 2004, the worldwide consumption of fats and oils was 130 mio tons (83% plant, 17% animal). 81% went into nutrition, 11% into the chemical industry, 5% into animal nutrition and 3% into motor fuels. In 2008, the world consumption was 165 mio tons, but now 9% were used for motor fuels (biodiesel, methyl esters of fatty acids). Surface active compounds (e.g. detergents) are the most important chemicals based on fats and oils. Many pharmaceuticals and cosmetic products use chemicals derived from fats and oils. The trend for “green products” drives the market. Palm and coco oils (30 %), followed by soya (23 %) and animal fats (17 %) are major resources. For Europe, rape and sun flower are the most important plants. Biodiesel FAME (fatty acid methyl esters) is a sizeable product especially in Germany. Table 1. Worldwide consumption of biomass in 2008 % Fats and oils

43

Starch

24

Cellulose

12

Sugar

9

Fibres

8

Rest

4

300

KEIM

Table 2. Products derived from sugar and starch • food industry • paper/textiles • polymers • detergents • pharmaceuticals • enzymes • vitamines • artificial sweetner

• amino acids • ethanol • 1,3propandiol (Du Pont, Sorona®, 140.000 t) • nbutanol (Du Pont, BP) • methacrylic acid (Perstorp) • polylactic acid (Purac)

In the productions of FAME substantial amounts of glycerine are produced as byproduct searching for an application [11]. The company Neste Oil has intro duced a glycerine free process “Nest BTL”, in which fats/oils are hydro processed. A 100000 t plant is oper ating in Finland. Due to the competition with nutri tion, search for plants like Jatropha, which grow in semi deserts, is going on. 2.2. Sugar and Starch The most important sugar is sucrose a disaccharide of glucose and fructose, native in sugar beets and sugar cane. In 2008, the world production amounted to 169 mio tons, from which 30% were traded [12]. Starch is a polymer from glucose. On hydrolysis starch yields glucose. For industrial applications amy lopectin is of higher value than amylose. About 50% of starch stems from corn. Other important sources are potatoes and wheat. Besides sugar starch is the most important raw material for glucose. Sugar and starch are used by the chemical industry for chemical syntheses and fermentation (white bio technology). The world market volume for sugar derived chemicals and products shown in Table 2 is estimated at 55 billion Euros. Bioethanol is by far the biggest product from sugar/starch due to its application as motor fuel via direct addition of ethanol to gasoline or indirectly via ETBE steming from the reaction of ethanol with isobutene.

Bio-ethanol

–H2O

Ethene Dimers

Propene

Metathesis

Butene-2

Fig. 2. C2 ⎯C4 bulk petrochemicals from bioethanol.

Interestingly, the use of bioderived fuels was used by Diesel and Ford to fuel the first cars. Also the Chi cago Tribune emphasizing ethanol writes on 12.5.1907 “Increasing attention lately has been given to the pos sibilities of obtaining power from alcohol by means of the internal combustion engine. From many points of view the advantages of alcohol over petroleum spirit, which hitherto has been in chief demand, are clear and pronounced. …In looking at agriculture for future sources of power, it is to be remembered that the solid would constantly be in position to provide fresh stores of raw material, the oxygen, hydrogen, and carbon of the alcohol being mainly derived from the atmosphere, while the ashes and mineral products would return to fertilize the ground.” For the production of ethanol different plants are used. (2008: Europe sugar beets and grain (2.2 mio tons ethanol), USA corn (28 mio tons ethanol), Brazil sugar crane (20 mio tons ethanol). Ethanol derived by sugar/starch as motor fuel is seen by many critically regarding environmental ben efits even costs [13]. An other fuel application based on sugar/starch is nbutanol. BP and Du Pont investigate this route in pilot plants. nButanol offers many advantages regard ing the carbon to oxygen ratio, energy content and vapour pressure [14]. Even bulk petrochemicals like C2–C4olefins can be based on bioethanol as elucidated in Fig. 2. In Brazil, Dow plans to manufacture polyethylene from bioethanol. An other sugar/starch based bio renewable route to chemicals is called “white biotech nology”. Here the synthesis of amino acids may serve as an example. Worldwide 2 mio tons of the amino acids Llysine, Lthreonine, Ltryphtophan are man ufactured. Worth mentioning in this connection are biopolymers. Cargill Dow converts lactic acid into polylactic acid (PLA), which is used, for instance, in packing food. Polyhydroxybutyrate (PHB) is another polymer of interest. In this connection it should be remembered that cellulose’s were the first biopoly mers. Markets eroded as ingenious petrochemically derived polymers arose. 2.3. NonFoodBiomass (Second Generation BioChemicals) For the chemical and energetic use of first genera tion biochemicals concern came up regarding [15]: • competition with nutrition • availability of sufficient land • cost • questioning of the ecological benefit. With a growing world population short of food, it will be irresponsible to convert food into chemicals. The introduction of biofuels has seen a price increase for food. In Mexico unrests came up because the price PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010

PETROCHEMICALS: RAW MATERIAL CHANGE FROM FOSSIL TO BIOMASS?

FischerTropsch

Biomass

301

Refining Material feedstocks organic chemistry

Synthesis gas

Methanol

Further processing

Energetic transportation fuel heating oil

Fig. 3. Gasification of biomass.

of corn (maize), which was exported to the USA where people were willing to may more, went up significantly. Land needed for nutrition becomes scarce. In 1950, 0.52 ha land for farming were available per per son, in 2000 0.25 ha and for 2050 only 0.16 ha per per son are predicted. This situation has led to deforesta tions (rain forests) to increase farming land. The use of nonfoodbiomass could circumvent above problems. Nonfood biomass embraces natural products consisting mainly of biomass such as wood, hay, straw, grass and many other materials. The key to its utilization rests with lignocellulose biomass, which is abundant in nearly unlimited amounts. For a long time, lignocellulose is used in the paper industry, which consumes 280 mio tons of wood. The “black liquor” produced as residue in the paper industry con tains already chemicals such as vanillin (5000 t) acetic acid, furfural (150000 t), methanol and many more. However, we are phased with lacking technology to utilize biomass in great scale to substitute fossil raw materials. Worldwide numerous research efforts have been started to find ways to convert cellulosic biomass into products applicable in the chemical or energy providing industry. Various approaches are under investigation applying thermal, chemical or biochem ical methods: • production of biogas (CH4) followed by C1 chemistry • gasification to CO/H2 followed by syngas con version (e.g. FischerTropsch or methanol chemistry) • liquefaction/pyrolysis to biooil followed by refining or gasification of the biooil • chemical, biochemical break down (hydrolysis) to diversified chemicals • direct use of complex molecules derivable from biomass. PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010

Biomass can be converted to biogas, which consists mainly out of methane, which could substitute natural gas in all its current industrial applications or novel reactions (methane challenge) [15]. The thermal pathway (gasification) leading to syn thesis gas is shown in Fig. 3. The FischerTropsch syn thesis is a well proven technology practised in some countries, especially by SASOL in South Africa. Besides fuel production SASOL operates a substantial chemical business based on C2–C12olefins and alco hols. The conversion of synthesis gas into methanol is carried out in a huge scale already. Methanol can be used directly as a motor fuel or as a feedstock for fuel cells. Also a well proven technology exists for conver sion of methanol into C2–C4olefins (MTOmethanol to olefins; MTPmethanol to propylene). The liquefaction/pyrolysis route involves thermal treatment of biomass to a gas, liquid and solid part. The liquid part (biooil) could be processed in a con ventional refinery or gasified [16]. For a chemical, biochemical break down (e.g. hydrolysis) separation of biomass (lignocellulose) into lignin, hemicellulose, cellulose, extracts and residue is required. The separated materials can yield: • lignin: vanillin, furfural, phenols, benzene poly mers • hemicellulose: xylose, furfural derivatives, alco hols (e.g. ethanol), amins • cellulose: glycose, alcohols, lactic acids •extracts: terpenes, fats/oil. Chemical and biochemical routes exist to convert lignocellulose into chemicals like: levulinic acid, ita conic acid, hydroxymethylfurfural, succinic acid. These compounds could become key chemicals for a novel biobased industry. In Fig. 4 it is demonstrated, how 5hydroxymethylfurfural could become the pillar for polymers substituting polymers from crude oil.

302

KEIM 2,5furandicarboxylicacid

Polyurethane Poliyester

5HMF

2,5dihydroxymethylfuran

Poliamides Termoplastic

2,5diaminomethylfuran

Elastomers

Fig. 4. Polymers base on 5hydroxymethylrurfural.

The US Department of Energy (DOE) has for warded a list of 12 chemicals derived from biomass, which are classified as platform chemicals [20]: 1,4diacids (succinic, furmaric, malic), 2,5 furandicarboxyIic acid, 3hydroxy propionic acid, aspartic acid, glucaric acid, glutamic acid, itaconic acid, levulinic acid, 3hydroxy butyrolactone, glyc erol, sorbitol, xylitol/arabinitol. Within the context discussed above, the concept of a biorefinery, which is an integrated approach to con vert biomass into chemicals, substitution, petrochem icals, and chemicals useful as biofuel is considered [17–19]. Figure 5 elucidates the concept of a bio refinery. In a biorefinery energy and biochemicals will be provided from biomass (lignocellulose). There is

always a residue, which can be gasified. The picture of a biorefinery parallels that of a mineral oil refinery. Again energy and petrochemicals are the major aim. The residue can be converted to coke, which can be gasified. At this time it is impossible to predict the exact pathway, which will emerge for the material and ener getic use of biomass. Research and development efforts in the following areas will guide the future: • effective separation of lignin, cellulose and hemicellulose • development of thermal, chemical and biochem ical means • integration of bioproducts into the existing petroleum derived industry • development of novel keychemicals (hemicel lulose line and cellulose line) • progress in plant breeding. Especially the plant breeding offers great potential. Here Craig Venture may be quoted: “It isn’t difficult to change algae to produce oil”. 3. CONCLUSIONS The development of the world is market and indus try driven. Determining factors in the market driven part are: consumer interest, sustainability, legislation, public opinion, independence, population growth. The biggest impact will come from our population growth narrowing and burdening our resources. Our greatest problem in envisaging future changes is the behaviour regarding consumption. If all people in this

Biomass lignocellulose

Crude oil

Separation into lignin, hemicellulose, cellulose, extracts, residue

Energy Bioethanol Biodesel Biogas

Residue

Biochemicals Substituting crude oil (e.g. C2 ⎯C4 olefins) aromatis

Destillation

Energy

Residue

Transpotation Fuel Heating oils

Petrochemicals C2 ⎯C4olefins aromatics

Fig. 5. Concept of a biorefinery. PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010

PETROCHEMICALS: RAW MATERIAL CHANGE FROM FOSSIL TO BIOMASS?

world will consume the same amount of mineral oil as the industrialized countries do, resources will run out very soon. The industry driven part embraces: avail ability, secure supply, price, competition, technology. Especially the part technology will have a great impact. To manufacture all the petrochemicals func tionalization was needed. For the use of biomass sepa ration technologies and ways to defunctionalize biom ass are needed. In the past, the chemical and energy providing industry were always linked together. Wood was used for making fires and for making chemicals, so was coal and mineral oil used energetically and chemically. The same can be expected from biofuels and biochemi cals. Biomass stands out as the only option with poten tial regarding scale and availability. Short, medium and long term developments can be envisaged. Short and medium term we will see a raw material mix as is shown in Fig. 6 for two potential gas/methanol and ethanol To predict the timing of the raw material change from fossil to bio is impossible. It will depend on many factors: • reserves to be found or more efficient production of oile, gas and coal • consumption • improving efficiency • switching to electric (cars). There are still many unknowns regarding future oil and gas discoveries. Here only gas hydrates may serve as an example. Today, only 30–40% of the oil present is recovered from an oil field. Which consumption will account for population growth and increase in living standard? Better tech nology will cut down consumption. Smaller cars with improved engines, for instance, will lower fuel con sumption. Harvesting the sun and going electric will free car bonaceous materials. Jules Verne in his book “The Mysterious Island” has predicted in 1874: H2 O

hν catalyst

H 2 + 1/2O 2 ,

“Yes, my friends, I believe that water will one day be employed as fuel, that hydrogen and oxygen which con stitute it, used singly or together, will furnish an inex haustible source of heat and light, of an intensity of which coal is not capable. As long as the earth is inhabited it will supply the wants of its inhabitants, and there wilt be no want of either light or heat as long as the productions of the veg etable, mineral or animal kingdoms do not fail us." There is no doubt in the mind of the author that industrial biotechnology will be the key technology of the 21 century, but crude oil and natural gas will remain the pillars of the chemical industry for many decades to come. PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010

Mineral oil natrual gas coal biomass CO2

CO/H2 CH3OH

Biomass

303

Basic chemicals todays indastrial chemicals, energy

Bioethanol

Fig. 6. Option for raw material mix.

Especially regarding the vast complexity and scale strains within the system cannot be resolved easily or quickly, but we see the first changes. A report by Shell predicts that by 2050 only 15% of primary energy will be biobased [21, 22]. In Spring 2010, a report edited by the author “Rohstoffbasis im Wandel” (raw materials and change) will appear covering the raw material change from fossil to bio [23]. REFERENCES 1. C.J. Campbell and J.H. Laherrere, Scientific Ameri can, March 78 (1998). 2. H. Bardt, BGR, IW (Institute der deutschen Wirtschaft Koln) 36 (2008). (www.divKoeln.de) 3. H.J. Kümpel and H. Rempel, Erdöl Erdgas Kohle 124, 196 (2008). 4. G.A. Olah, “Beyond Oil and Gas, the Methanol Econ omy” (Weinheim, WileyVCH, 2006). 5. F. Asinger, “Methanol, Chemie und Energierohstoff”, (SpringerVerlag, 1986). 6. K. Weissermel, Angew. Chem. 92, 75 (1980). 7. E.S. Lipinsky, Science 212, 1465 (1981). 8. Dechema and VCI paper “Verwertung und Speicherung von CO2” (Jan. 2009. Can be ordered via A. Bazanella Dechema, Frankfurt). 9. J.H. Clark, F. Deswarte “Introduction to chemicals from biomass” (Wiley Series Renewable Resource, 2009), ISBN 9780470697474. 10. C. Stevens, R. Verhe “Renewable Bioresources” (Wiley, 2009), ISBN 9780470854464. 11. A. Behr, J. Eilting, K. Irawadi, J. Leschinski, and F. Lindner, Green Chemistry 10, 13 (2008). 12. F.O. Licht, Int. Sugar & Sweetener Report 141, 30 (2008). 13. EVCAR/JRC/CONCAVE “Well to Wheel Analysis of future automotive fuels and power trains in the Euro pean context” (2004). 14. R. van Noorden RSC (The Royal Society) document 01/08. Chemistry World 2, 31 (2008).

304

KEIM

15. D. Deublin, “Biogas from waste and renewable resources” (WileyVCH 2009), ISBN 9783527 621705. 16. N. Dahmen, E. Dinjus, E. Henrich, Oil Gas European Magazine 1, 31 (2007). 17. B. Kamm, P.R. Gruber, and M. Kamm “Bio refineries  Industrial Provesses and products” (Wiley VCH, Weinheim, 2006). 18. B. Kamm and M. Kamm, Chemie Ingenieur Technik, 79, 592 (2007).

19. T. Hirth, S. Rupp, and W. Trösch, Chemie Ingenieur Technik, 81, 1697 (2009). 20. US DOE DOE/60102004; T. Werpry, Top value added chemicals from biomass, Oak Ridge. 21. J. Kramer and M. Haigh, Nature, 462, 568 (2009). 22. Shell Energy Scenario to scenarios 2050 www.shell.com/scenarios 23. Eds. by W. Keim and M. Röper, “Rohstoffbasis im Wandel” (can be ordered via Dechema or GDCh Frankfurt).

PETROLEUM CHEMISTRY

Vol. 50

No. 4

2010