Whether coal, gas or even biomass will replace petroleum as the chemical raw material of the future is not yet clear. However, one thing is certain. Alternatives will be needed in the long term despite that fact the even pessimists predict that oil will be available for the next forty years. High prices, increasing consumption in Asia and the chaotic political situation in the oil producing countries add an element of urgency to the discussion on diversification of the raw material base. The industry is looking for an intelligent mix and an evolutionary approach to the supply of raw materials.
Petroleum is still the number one raw material in the chemical industry, but companies have already begun to look for alternatives. Degussa, Dupont and BASF are all looking at other raw materials. There is good reason why the head of research at BASF, Dr. Stefan Marcinowsky, has identified the search for alternative sources of raw materials as one of the major challenges for the future. “Particularly in Europe, we have to find alternatives to oil,” he said.
The chemical industry only consumes about two percent of annual oil production, but price increases are having a noticeable effect. The price of naphtha has tripled during the past three years, rising from $200 to $600 per ton, and it has become a significant cost factor, explained Marcinowsky. The costs are closely linked to energy prices, and the prices have been moving only one way in recent years, namely up. Over the next two years, BASF will be investing 100 million euros to satisfy the growing demand for alternative raw materials and another 160 million in white biotechnology. The company is looking for alternative sources of synthetic gas, ethylene, propylene, butadiene and aromatics which are important starting materials in the value-add chain at BASF. It is also developing techniques which will enable it to use renewables. “More than 50 percent of our investment in the alternative raw materials cluster goes into renewables,” added Marcinowsky.
Cellulose is one of the favorites. More than 700 billion tons of cellulose are available worldwide, making this raw material for the fiber industry the most abundant source of organic raw material on the planet. Two alternatives have been used in the past to produce cellulose fiber. The first is the more complex viscose process involving several steps in which caustic soda and carbon disulphide are used to convert insoluble cellulose into a high-viscosity solution which is suitable for spinning. The second method is the Lyocell process, which makes the cellulose fit for spinning in one process step by directly dissolving the cellulose in NMMO (N-methylmorpholine-N-oxide). BASF is looking at a third alternative. “Ionic fluids offer new ways of using cellulose as a raw material,” explained Marcinowsky. The company is engaged in collaborative research projects to explore ways of using ionic fluids to further simplify the solution process and to more accurately adjust fiber characteristics than is possible with conventional methods.
The search for new strategies
Up until this point, the major technique for exploiting renewables has been fermentation. “We are concentrating on biopolymers, proteins, enzymes and chemicals,” explained Dr. Oskar Zelder from the specialities chemical research group at BASF. In addition to biopolymers which are accessible through fermentation such as PHB and enzymes like thermostable glucananase and xylanase for animal feed, BASF is also looking at the fermentation of succinic acid. This molecule represents the biocatalytic entry point into the C4 value-add chain and could provide the basis for tetrahydrofuran synthesis. THF is an important solvent for resins, adhesives and lacquer, and it is also used in the production of the polyurethane raw material polytetramethyleneglycol, making it a key compound at BASF. “The production of THF from succinic acid is still in the exploratory stage, because THF can be made from a number of different raw materials. We are currently looking at the cost structure of the different sources,” explained Marcinowsky.
That is a central issue in the discussion on renewables. Availability is a major consideration, but so is price. The production of bulk chemicals will only be competitive if cheap raw materials are available. At the moment, rapeseed, grain, sugar beet, etc. are used mainly to produce biodiesel and bioethanol.
The energy market is in competition with the chemical market. As result, the price of renewables is becoming increasingly linked to energy prices, and this is a source of concern for Marcinowsky.
In the case of glycerin on the other hand, the energy market is having a positive effect on the chemical industry. As biodiesel capacity increases dramatically, more and more glycerin is produced as a byproduct (200,000 – 300,000 tons according to some estimates). This drives prices down, making glycerin an attractive raw material in chemical production. Researchers are looking at bioconversion as a way to make1,3-propanediole from glycerin, produce biopolymers and, in the catalytic carbonylation of glycerin using carbon monoxide, for the production of dicarboxylic acid. The market for synthetically produced glycerin has collapsed following the fall in prices. Solvay has shut down its epichlorine-based synthesis of glycerin and switched to a completely new process which eliminates the need for petroleum-based epichlorohydrin. The new Epicerol process will start up at the Tavaux plant in France, and there are plans to invest in new production facilities in Rheinberg and Asia.
Shifting the emphasis
Process innovation and new conversion technology will be needed to drive the transition to new raw materials. This is particularly true for coal and natural gas. Gas is one of the major energy sources along side of oil, but it has not played a significant role in chemical production up to this point. That scenario may change soon in propylene production. Propane and methane are some of the most useful constituents of natural gas. Propylene, can be produced through the dehydrogenation of propane, is an important intermediate which is used to make plastics such as polypropylene. In the past, propylene was produced during the steam cracking process which was used to make ethylene as the main product. However, experts believe that demand for propylene will outstrip demand for ethylene. “There will be shortage of 3 million tons of propylene by 2006 which cannot be compensated for with conventional methods,” explained Dr. Ludolf Plass who is head of technology at Lurgi. This is an opportunity for an alternative approach, and there are four possibilities: UOP’s Oleflex process, ABB’s Catofin process, Uhde’s Star process and a process which was jointly developed by BASF and Linde and which is now in the pilot phase.
Focusing on synthetic gas
In the medium to long term, the focus will shift from the fossil trio oil, gas and coal to gas and coal. China, which has large reserves of coal, is one of the major players in the search for new coal liquefaction and gasification technology to reduce the country’s dependence on oil. Lurgi engineers are doing good business in China with their methanol to propylene process. A contract valued at more than 100 million euros at two new plants (total contract value exceeds one billion euros), which will make plastics out of coal, underlines the importance which China’s leadership attaches to new technology.
A process which was developed before the Second World War will be used for coal liquefaction. The Fischer-Tropsch process can be used to convert coal to synthetic gas and then liquefy the gas to for use as fuel or as a raw material in the chemical industry. The process enabled Germany to eliminate its dependency on oil during World War II. South Africa uses its large coal reserves to supply a large portion of the fuel that is consumed in the country. Pyrolysis can be used to synthesize gas from biomass as well as from coal, and this is where a new process from the research center in Karlsruhe enters the scene.
The process is called biomass to liquid, and it generates synthetic gas from wood, straw and agricultural waste. The synthetic gas can then be used as a starting material for fuel or as a raw material in the chemical industry. The secret to this process is high-speed pyrolysis which was developed by Lurgi. A high-energy slurry is produced in a mixing reactor with a dual worm conveyor, increasing the energy density of the biomass by twenty times. The researchers in Karlsruhe are now placing the finishing touches on the pilot system, and an efficient gasification process is in the pipeline. “The goal of our research activities is to find ways of making chemical raw materials from biomass,” explained Dr. Eckhard Dinjus, Director at the Institute for Industrial Chemistry.
Ideals like this show that the industry is ready to embrace change. However, despite the discussion which has now gotten underway and some initial attempts to move away from oil, the raw material base in the industry will not change overnight. Naphtha produced in oil refineries will remain the key raw material for several decades to come. “There will have to be more than one solution. The important thing is to find an intelligent mix,” commented Marcinowsky.
Biorefinery – a vision for the future
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