Mechanical PulpingTechnologies & Measures
|Technology or Measure||Energy Savings Potential||CO2 Emission Reduction Potential Based on Literature||Costs||Development Status|
|RTS Pulping||A study estimates RTS pulp can be manufactured with about 15% lower specific energy requirements than pulp produced with conventional refining system. Another study reports specific energy of RTS pulping process 20% lower than Thermo-mechanical pulping. Increasing rotational speed on TMP refiners are estimated to reduce energy use between 15 to 30%, depending on plate type and refiner mode (Kramer et al., 2009. p.99). Savings are estimated at 306 kWh/t-pulp (Martin et al., 2000. p. 24||Emission reduction potential is estimated at 128 kg CO2/t-pulp (Martin et al., 2000. p. 21)|
Implementation costs are estimated around $50/t-pulp (estimation from the year 2000) (Martin et al., 2000. p. 24)For a typical mill with 1000 ton per day capacity, a reduction of 20% in motor power requirement translates into $5 million annual savings (Sabourin, 2006).
A newspaper mills applied refiner control strategy to minimize variations in the freeness of ultra high yield sulfite pulp saved 51.3 kWh/t product.
By decreasing consistency of pulping from 50% to 30%, 7 to 15% electricity savings possible in Thermo-mechnical and refiner mechanical pulping.
Savings due to mechanical improvements are estimated at 11%. (Kramer, et al., 2009. p.96)
Double disc refiners used in some Swedish and Norwegian mills consume aroun 300 kWh/t less energy than single disc refiners (BREF, 2010. p. 471).
Potential electricity savings of 11% may be achieved at the capital cost of around $7.7/ton (2000 dollars) of pulp production (Kramer, et al., 2009. p.96).
|Thermopulping||Studies suggest that this technique can reduce specific energy consumption compared to thermo-mechanical pulping by up to 20% (Kramer et al., 2009. p.98).||Commercial|
|Heat Recovery in Thermo-mechanical Pulping|
One study estimates heat recovery systems for pressurized refiners can generate 1.1 to 1.9 tons of clean steam at dryer pressure per ton of pulp (Kramer et al., 2009. p.99).
For a 150 tpd plant, recovery of 695 GJ of energy in the form of steam and 1175 GJ of energy in the form of hot water is reported (NEDO, 2008. p.166)
|Average installation costs have been estimated to be $21/t-pulp (2000 dollars), with significant increases in operation and maintenance costs. Payback periods vary widely depending on capital costs, but can be as low as a few months (Kramer et al., 2009. p.99) The payback time for the investment is usually around 1 year (BREF, 2010. p. 462)||Commercial|
|Pressurized Groundwood||Electricity savings of 20 to 36 percent comparing to mechanical pulping processes at atmospheric pressure are reported in literature (Kramer, et al., 2009. p.96).||Commercial|
|Installation of High Efficiency Refiners|
The power saving of about 290 kW had been achieved.
Total installation cost of central refining system is estimated to be Rs. 5.60 Crores.
|New Energy Efficient TMP Process||The conventional TMP process consumes electricity in the range 1600 - 3200 kWh/ADt. The new efficient process promises the energy consumption reduction by 200 - 450 kWh/t.||Energy savings must be balanced with investment.||Commercial|
|Low Consistency Refining (LCR)||The application of 100 to 200 kWh/t in LC refining can replace 200 to 400 kWh/t of high consistency refining at comparable freeness and tensile strenth (IPW, 2010. p. 24) Energy savings by 142 kWh/t thermomechanical pulp can be achieved.||CO2 savings by 16.3 Kg/t is estimated.||Commercial|
|Improvements in Chemi-Thermomechanical Pulping (CTMP)|
Energy savings of about 283 kWh/t is estimated if the first refiner speed is increased and pH of the sulphite liquor is decreased (Martin et al., 2000. p.26).
Emissions saving by 128 kg-CO2/t is estimated (Martin et al., 2000. p.20).
Retrofit cost of implementing the improvement is estimated to be $300/t (Martin et al., 2000. p.26).
|Advanced Thermo Mechanical Pulping (ATMP)||A 300-800 kWh/t energy saving for a given pulp tensile strength has been confirmed at mills running the combination of chemicals and mechanical treatment alone.||Commercial|
Mechanical Pulping Publications
This Energy Guide discusses energy efficiency practices and energy-efficient technologies that can be implemented at the component, process, facility, and organizational levels.