NewPage Corporation, the American paper and pulp manufacturer, has formed a partnership with Swedish Chemrec. Under the agreement, Chemrec is to start by carrying out a feasibility study on setting up a plant for black liquor gasification (BLG) at NewPage´s pulp mill in Escanaba, Michigan. ‘The plant we´re planning will be some 25 times the size of the development facility we´re already running in Piteå,´ relates Chemrec´s CEO Jonas Rudberg.
Black liquor is the liquid waste product from the cooking of wood chips to make paper pulp. With its very high energy content, this liquor is worth processing to recover the energy, as well as the cooking chemicals, it contains. At present, this is done by means of combustion in soda recovery boilers: cooking chemicals are thereby recovered, and steam and electricity are produced. If, instead, the black liquor is gasified under pressure, a substantial rise in energy efficiency is attained. This permits a considerable increase in the cash flow from the pulp mill, either through raised production of green electricity or through production of renewable motor fuel.
The BLG research programme has been funded by Mistra and the Swedish Energy Agency since 2004. In the course of the programme, researchers have obtained extensive new knowledge, which has enhanced understanding of the process. In its development facility in Piteå, Chemrec has been able to show that the technology is robust and ready for upscaling.
These results mean that the technology can now be exported. In Jonas Rudberg´s view, it is logical for Sweden to be responsible for its development.
‘The American pulp industry dates back further than the Nordic one, and research in the pulp industry takes places largely in Sweden and Finland nowadays. The fact that it is a relatively small Swedish company signing a contract in the American pulp industry is a consequence of our position on the frontline of research.
LEADING-EDGE RESEARCH
The research team in Piteå will collaborate with Chemrec to upscale BLG technology for the plant in Michigan. In October Rikard Gebart, the BLG programme manager, is to visit Michigan to find potential partners — engineers as well as researchers — for the Piteå group to collaborate with.
‘Naturally, it´s great fun and stimulating to be part of current progress, and to see that the technology we´re developing is in demand. It really feels as if we´re at the leading edge of an advance that may revolutionise the whole pulp industry,´ says Rikard Gebart.
For the pulp industry, BLG means that the sector can become self-sufficient in electricity, but also that it can become a fuel producer.
The technology used for BLG was invested 20 years ago. Why has there not been greater interest before now?
‘Energy has been too cheap to date, but three years ago when the oil price began to rise investing in alternative energy systems became interesting. What makes our technology attractive in the American market is the fact that it increases energy efficiency and makes it possible to boost cash flow by producing fuel, especially dimethyl ether (DME), but also methanol,´ says Jonas Rudberg.
ECOLOGICAL CYCLE
DME works well in moderately converted diesel engines, and has major advantages compared with ordinary diesel. It is more energy-efficient, as well as emitting considerably smaller quantities of particles than ordinary diesel.
Nor do emissions of carbon dioxide from the use of DME afford any net contribution to greenhouse gases, since the CO2 forms part of an ecological cycle. The Piteå researchers, in cooperation with Volvo, Preem and other companies, have applied for EU funds for a project in which they are to use the gas they are already producing to make DME.
Jonas Rudberg believes that, within a couple of years, the plant in Piteå will be able to produce DME for a commercial market. And when it comes to green fuel of the future, as Rikard Gebart sees it, DME is part of the solution.
‘Next-generation fuel will be a mosaic of different solutions. What we´re working on now is one piece of the jigsaw puzzle,´ he says.
RENEWABLE FUELS
Dimethyl ether (DME)
A gaseous fuel for diesel engines, with good emission characteristics. DME can be produced from fossil gas as well as biomass, and gives rise to low emissions of substances harmful to health and the environment.
Ethanol
Some of the ethanol used for vehicle fuel in Sweden today comes from a factory in Norrköping and is based on Swedish wheat. But most of the ethanol is imported from Brazil and elsewhere, and is based on sugarcane.
Fossil gas and biogas
Both consist of methane, but they have different origins. Fossil gas is, by definition, non-renewable: it has come into existence as a result of processes over millions of years. Biogas, on the other hand, is extracted from fresh organic waste, such as sludge from sewage works.
Rape methyl ester (RME)
RME is produced from rapeseed oil. Diesel vehicles, both light and heavy, of several makes are approved for RME operation.
Methanol
Methanol is produced today in large quantities from fossil gas. Methanol can also be produced from biomass. However, none is currently being produced in Sweden. Methanol is an interesting option because it can function in certain types of fuel cell.
