Showing posts with label Forest biorefinery. Show all posts
Showing posts with label Forest biorefinery. Show all posts

Sunday, February 15, 2009

Pulp Mill: A Natural Home for the Forest Product Biorefinery

It is costly to start a greenfield biorefinery plant. When we closely look at pulp and paper industry, it will not hard to find:
  • this industry is the largest handler of forest residues (lignocellusics)
  • $Millions investment has been completed in infrastructure, which will allow to save ~ 35% of capital cost versus a greenfield plant and utilize the boiler house, generators, control rooms, pipe bridges, water and effluent stations, warehouses, woodyards, wood procurement, storage tanks etc
  • Hundreds of highly trained technical professionals are available for cellulosic biorefineries
  • Co-production and process integration reduce allocated production cost for both pulp mill and biorefinery plant
  • Bioethanol adds additional revenue to pulp and paper mills

There, when we borrow the ideas from paper industry to treat biomass , somehow we should not turn our attention away from this industry. More we can take advantge of them.

Thursday, November 20, 2008

The Integrated Forest Product Biorefinery (2)

A modern pulp mill employs about 70% of the technologies needed by a biorefinery and provides a means of “fast tracking” the development of innovative biorefinery technologies.

Although the conversion of wood cellulose into a sugar-rich process stream has been extensively studied, it is frequently overlooked that economic factors favor the manufacturing of paper over biofuels/biochemicals, making the practical success of this approach doubtful. In sharp contrast, wood glucomannans are rapidly extracted and degraded in the Kraft pulping process to isosaccharinic acids and not utilized as a significant part of pulp fibers. Degraded glucomannans end up as energy during black liquor gasification. Because of the relatively low heating value of hemicellulose, it contribute only 15-20% of heating value to black liquor. Therefore, hemicellulose is worth more as ethanol/chemicals than as energy.

Energy values of different fuels in an IFBR
Fuel Heating Value(GJ/MT)
Oil 43.5
Biomass (20% H2O) 15
Black liquor (80% ds) 12.6
Lignin 26.9
Carbohydrates 13.6

Hemicellulose (mainly xylose in hardwood, grass and agricultural crop residuals and glucomannan in softwood) comprise ~ 5 – 26% of biomass and are an under utilized biochemical resource that could be readily converted to bioethanol/biochemicals. The removal of these hemicellulose prior to kraft pulping should improve the overall kraft pulping process by reducing cooking times and improving chemical impregnation. These process benefits will facilitate practical implementation of this biorefinery concept.


Prior to Pulping Approach:
  • Uses hot water extraction vessels to extract hemicelluloses
  • Acetic acid is separated, and sugars are fermented to fuel grade ethanol with known processes as shown below
  • Removing the “sugars”improves throughput potential of existing operations such as pulping and chemical recovery
  • Ethanol is at the low end of potential products
  • Development of further value includes biorefining systems to produce high-value chemicals as well as biodiesel and ethanol





Post-Pulping Approach:
• Extraction of cellulose- and lignin-derived chemicals from black liquor
• Recovery of tall oil soap and extractives from black liquor
Gasification of black liquor residuals, wood waste, and other biomass to produce syngas
• Conversion of syngas to methanol, DME, ethanol, Fischer-Tropsch fuels, etc.







Wednesday, November 19, 2008

The Integrated Forest Product Biorefinery (1)

It has been generally acknowledged, that North America’s forest products industry must consider new manufacturing strategies and new products if they want to stay competitive in the global market place. One of the industry’s strength is the fact that it is one of the few nationally based industries that have the necessary skill set and infrastructure available to collect and process sufficient biomass for the rapid development and commercialization of biorefining technologies in the near future. The development of biorefining technologies leveraged with pulp manufacturing would be one of the few technological solutions that would avoid the $0.5-1 billion of new investment costs needed to develop a biorefinery capable of processing 1,000-2,000 tons of wood a day.
The forest product industry is part of the manufacturing sectors that convert wood into high-value products and can contribute about 5% to current U.S. GDP. It frequently provides employment in many rural one-industry towns critically dependent upon their natural wood resource such as in the states of Georgia, Wisconsin, Michigan, Maine, Alabama, Arkansas, etc. Unfortunately, the recent downturn in the pulp and paper industry and composite wood products sector has resulted in permanent closure of many pulp and board manufacturing facilities. As a reult, these plant closures put those states that are dependent upon the forest industry as a main contributor to economic health and employment in an extrem difficulty situation. The loss of pulp mills has led to substantial increases in rural unemployment and reductions in future economic growth.
Recently there is a renewed interest in the production of biofuels and bio-based chemicals from lignocellulosics because they are derived from a renewable and carbon-neutral feedstock contrary to their fossil fuel-based counter parts. In addition, oxygen rich chemicals are in principle easier to make from the sugar components present in lignocellulosics by mostly fermentation routes, as compared to complex catalytic conversions of oxygen deficient feedstocks such as oil or natural gas. Within these challenging economic conditions tremendous new opportunities are developing in the forest product industry. The conversion of the fuels industry from hydrocarbon-based technologies to carbohydrate-based would dramatically improve rural employment opportunities, enhance national security, and improve environmental performance, including reductions in CO2 emissions, which is so-called "carbohydrate economy".
Traditionally, pulp mills have one main product stream: From wood chips to pulp fiber (and thermal energy). When looking at this industry, it is not difficult to find that pulp mill is a Natural home for the forest product biorefinery because the pulp and paper industry is the largest handler of forest residues (lignocellusics) and has put tons of money to build the infrastructure such as boiler house, generators, control rooms, pipe bridges, water and effluent stations, warehouses, woodyards, wood procurement, storage tanks. These infrustructure can be used or co-utilized, which will save ~ 35% of capital cost compared to new greenfield construction. This industry already has hundreds of highly trained technical professionals that are available for cellulosic biorefineries. The co-production and process integration can reduce allocated production cost. The second product stream such as bioethanol and other biochemicals can add additional revenue to the industry. This is a new concept: The Integrated Forest Product Biorefinery (IFPB), which has two product steams: From wood chips to pulp fibers and biofuels/biochemicals.