| 1. |
- Algehed, Jessica, 1971, et al.
(författare)
-
Energieffektiv indunstning i framtidens massabruk
- 2001
-
Ingår i: Fiberlinjekonferensen 01, Stockholm 2001. - 1404-7098.
-
Konferensbidrag (refereegranskat)abstract
- Det arbete som presenteras i denna artikel har gjorts inom KAM-programmets energipotentialprojekt. KAM står för Kretsloppsanpassad massafabrik och är ett MISTRA-finansierat forskningsprogram, vars vision är en kretsloppsanpassad massafabrik som tillverkar högkvalitativa produkter och samtidigt utnyttjar vedråvaran så effektivt som möjligt. Förenklat kan man säga att avsikten med energipotentialprojektet är att finna effektiva energisystem för framtidens massa- och pappersbruk, som är tekniskt och ekonomiskt möjliga.För att spara energi i en fabrik måste processerna i sig göras mer effektiva, vilket naturligtvis sker i och med den ständiga teknikutveckling som pågår, men de måste även värmeintegreras bättre med varandra. Exempel på värmeintegration som redan sker är sekundärvärmesystem där värme från olika processdelar återanvänds och integrerade stripprar, som ”lånar” ånga från indunstningsanläggningen istället för att använda färskånga. Pinchtekniken är ett vanligt hjälpmedel för att finna vilka delar i en fabrik som bör värmeintegreras med varandra och vilket minimalt värme- och kylbehov man har när alla delar av fabriken är integrerade på ”rätt” sätt. Flera tidigare pinchstudier har visat att man i ett sulfatmassabruk uppnår störst ångbesparingar när man värmeintegrerar indunstningen med den övriga processen. Anledningen till detta är att indunstningen är en av de största ånganvändarna och samtidigt en av de mest flexibla processerna i ett sulfatmassabruk. I princip kan indunstningen värmeintegreras med den övriga processen på två sätt, antingen genom att indunstningen till viss del utnyttjar spillvärme från den övriga processen vid relativt låga temperaturer, dvs under 100°C, eller att indunstningen drivs vid så hög temperatur att den delvis kan leverera lågtrycksånga till den övriga processen. Dessa båda sätt att värmeintegrera indunstningen på har studerats vid Institutionen för värmeteknik och maskinlära och i denna artikel sammanfattas resultat från två vetenskapliga artiklar , , som handlar just om spillvärmedriven indunstning och indunstning driven med mellantrycksånga.
|
|
| 2. |
- Algehed, Jessica, 1971, et al.
(författare)
-
Energy efficient evaporation in future pulp and paper mills
- 2002
-
Ingår i: 7th Conference on New Available Technologies, SPCI 2002, Stockholm 2002. - 1404-7098.
-
Konferensbidrag (refereegranskat)abstract
- In this paper ways to design energy efficientevaporation plants in future pulp and paper mills arediscussed. There is more than 1 GJ/ADMT excessheat in the model mills studied that can be madeavailable for use in other parts of the mill. If thisheat is used for evaporation and/or if the evaporationplant is designed to use MP steam and deliver LPsteam to the steam network, large amounts of steamcan be saved. It is shown that these savings lead toreductions in CO2 emissions; the largest reductionare achieved if assuming that oil can be saved or ifbiomass fuel is exported from the mill and used toreplace oil elsewhere. It is also shown that theeconomic incentive for redesigning the evaporationplant depends on how the saved live steam is usedand the economic conditions assumed. The largestsavings are obtained if the live steam savings lead todecreased oil consumption. If producing condensingpower or excess bark that can be sold, the savingsare smaller, but in most cases still considerable in size.
|
|
| 3. |
|
|
| 4. |
- Algehed, Jessica, 1971, et al.
(författare)
-
Evaporation of black liquor and wastewater using medium-pressure steam : Simulation and economic evaluation of novel designs
- 2003
-
Ingår i: ScienceDirect. - 1404-7098. ; 23:4, s. 481-495
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, novel evaporation plant designs that use medium-pressure steam and deliver low-pressure(LP) steam to the steam network as well as conventionally designed plants are simulated and evaluatedfrom a technical and economic point of view. Both evaporation of black liquor only and combinedevaporation of black liquor and wastewater are analyzed.The results show that the novel designs suggested in this work all have large potential to save live steamand that an additional 8 m3 of wastewater/ADMT (air dry metric ton) can be evaporated without increasingthe mill´s total live steam demand. They also indicate that the demand for LP steam in the rest ofthe process is less important for the savings in live steam. The total cost for the novel designs and the relationship between that cost and the cost for conventional designs depend on the economic conditions assumed. If the investment in a more energy efficient evaporation plant is considered from a strategic point of view using an annuity factor of 0.1 and if the cost of thesaved fuel is rather high in comparison to the electricity price, the total cost for the novel designs will have alower total cost than the traditional designs.
|
|
| 5. |
- Algehed, Jessica, 1971, et al.
(författare)
-
Opportunities for process integrated evaporation in kraft pulp mills
- 2000
-
Ingår i: TAPPI Engineering Conference. ; , s. 841-849
-
Konferensbidrag (refereegranskat)abstract
- This paper discusses how medium high temperature excess heat made available through process integration can be used for evaporation of black liquor and different types of wastewater. The amount of medium high temperature excess heat varies considerably in different mills, and apart from a reference mill two other mills are simulated-one that uses a new dryer combined with non-conventional evaporation design and one minimum effluent pulp mill. Several new evaporation plant designs are technically and economically analyzed. The total number of evaporators, amount and temperature of black liquor and wastewater to be evaporated, as well as temperature and amount of excess heat available are varied. The economic value of the total energy savings due to the new evaporation design is shown, and the investment opportunity to make different amounts of excess heat available is stated. This work shows that the total live steam demand for today's and future kraft pulp mills can be reduced by at least 20% with a non-conventional evaporation design. The results also show that there is a relatively large investment opportunity to make excess heat available for evaporation.
|
|
| 6. |
- Andersson, Eva Ingeborg Elisabeth, 1956, et al.
(författare)
-
Energy efficient upgrading of biofuel integrated with a pulp mill
- 2006
-
Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 31:10-11, s. 1384-1394
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents and evaluates different energy efficient options for integrating drying and pelletising ofbiofuel with a modern energy efficient pulp mill process. When drying biofuel, a large amount of the heat input canoften be recovered. One option for heat recovery is to cover low-temperature heat demand in the pulping process.Alternatively available excess heat from the pulp mill can be used for drying. Both alternatives will contribute to abetter energy efficiency for the combined pulp mill and biofuel upgrading facility. Pinch analysis tools can be usedto estimate the excess heat potential at different temperature levels in the pulp mill. Three different technologies forpulp mill integrated biofuel drying were chosen for the study, namely steam drying, flue gas drying and vacuumdrying. The different technologies are evaluated on the basis of energy usage, global CO2 emissions and resultingpellets production cost, using stand-alone pellets production as a reference. The pulp mill assumed for thecalculations is the Eco-Cyclic reference pulp mill. The results of the study indicate that the most attractiveintegrated drying technology option is the flue gas dryer, using flue gases from the black liquor boiler. With theavailable flue gas stream at the reference pulp mill, a potential pellets production of 70,000 ton/yr could beachieved at a cost of 24.6 EUR/ton. The associated reduction in CO2 emissions compared to stand-alone pelletsproduction is 3136 kg/MWh-pellets.
|
|
| 7. |
- Andersson, Eva Ingeborg Elisabeth, 1956, et al.
(författare)
-
Energy Efficient upgrading of Biofuel Integrated with a Pulp Mill
- 2003
-
Ingår i: Proceedings of ECOS 2003, Copenhagen, Denmark. - 1404-7098.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents and evaluates different energy-efficient options for integrating drying and pelletising of biofuel with a modem energy-efficient pulp mill process. When drying biofuel, a large amount of the heat input can often be recovered. One option for heat recovery is to cover low temperature heat demand in the pulping process. Alternatively available excess heat from the pulp mill can be used for drying. Both alternatives will contribute to a better energy efficiency for the combined pulp mill and biofuel upgrading facility. Pinch analysis tools can be used to estimate the excess heat potential at different temperature levels in the pulp mill. Three different technologies for pulp mill integrated biofuel drying were retained for the study, namely steam drying, flue gas drying and vacuum drying. The different technologies are evaluated on the basis of energy usage, global CO2 emissions and resulting pellets production cost, using stand-alone pellets production as a reference. The pulp mill assumed for the calculations is the Eco-Cyclic reference pulp mill. The results of the study indicate that the most attractive integrated drying technology option is the flue gas dryer, using flue gases from the black liquor boiler. With the available flue gas stream at the reference pulp mill, a potential pellets production of 70 000 tonnes/yr could be achieved at a cost of 24.6 €/tonne. The associated reduction in CO, emissions compared to stand-alone pellets production is 31-36 kg/MWhpellets.
|
|
| 8. |
- Andersson, Viktor, 1983, et al.
(författare)
-
Algae-based biofuel production as part of an industrial cluster
- 2014
-
Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 71, s. 113-124
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a study on the production of biofuels from algae cultivated in municipal wastewater in Gothenburg, Sweden. A possible biorefinery concept is studied based on two cases; Case A) combined biodiesel and biogas production, and Case B) only biogas production. The cases are compared in terms of product outputs and impact on global CO2 emissions mitigation. The area efficiency of the algae-based biofuels is also compared with other biofuel production routes. The study investigates the collaboration between an algae cultivation, biofuel production processes, a wastewater treatment plant and an industrial cluster for the purpose of utilizing material flows and industrial excess heat between the actors. This collaboration provides the opportunity to reduce the CO2 emissions from the process compared to a stand-alone operation. The results show that Case A is advantageous to Case B with respect to all studied factors. It is found that the algae-based biofuel production routes investigated in this study has higher area efficiency than other biofuel production routes. The amount of algae-based biofuel possible to produce corresponds to 31 MWfuel for Case A and 26 MWfuel in Case B.
|
|
| 9. |
- Andersson, Viktor, 1983, et al.
(författare)
-
Efficient Utilization of Industrial Excess Heat for Post-combustion CO2 Capture: An Oil Refinery Sector Case Study
- 2014
-
Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 63, s. 6548-6556
-
Konferensbidrag (refereegranskat)abstract
- A key issue in post-combustion carbon capture is the choice of absorbent. In this paper two different absorbents, monoethanolamine (MEA) and ammonia (NH3), have been modeled in Aspen Plus at different temperatures for possible implementation at an oil refinery. The focus of investigation is the possibilities of heat integration between the oil refinery and the carbon capture process and how these possibilities could change in a future situation where energy efficiency measures have been implemented.The results show that if only using excess heat from the refinery for heating of the carbon capture process, the MEA process can capture more CO2 than the NH3 process. It is shown that the configuration requiring least supplementary heat when applying carbon capture to all flue gases is MEA at 120 °C.The temperature profile of the excess heat from the refinery suits the MEA and NH3 processes differently. The NH3 process would benefit from a flat section above 100 °C to better integrate the heat needed to reduce slip, while the MEA process only needs heat at stripper temperature.
|
|
| 10. |
- Andersson, Viktor, 1983, et al.
(författare)
-
Industrial excess heat driven post-combustion CCS: The effect of stripper temperature level
- 2014
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 21, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- The implementation of post-combustion CCS provides an opportunity for the oil refining sector to drastically decrease its CO2 emissions. Previous studies have shown that the largest cost is the heat supply to the stripper reboiler. When performing CCS at an oil refinery it could therefore prove economically beneficial to utilize the excess heat from refinery processes to meet this demand for heat. The present study investigates the heat demand in a stripper reboiler at different temperature levels from 120 degrees C down to 90 degrees C. At temperatures lower than 120 degrees C the heat demand increases, but the availability of excess heat also increases. A case study that connects heat demand results with data from an oil refinery shows that if only excess heat is utilized as a heat source, the amount of CO2 that can be separated is largest when the temperature in the stripper reboiler is 90 degrees C. If, however, CCS with a capture rate of 85% were applied to the four largest chimneys at the refinery, the external heat demand would be the lowest for the standard temperature of 120 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.
|
|
