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Rajendran, Karthik
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Publications (10 of 24) Show all publications
Kabir, M. M., Rajendran, K., Taherzadeh, M. & Sárvári Horváth, I. (2015). Experimental and economical evaluation of bioconversion of forest residues to biogas using organosolv pretreatment. Bioresource Technology, 178, 201-8
Open this publication in new window or tab >>Experimental and economical evaluation of bioconversion of forest residues to biogas using organosolv pretreatment
2015 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 178, p. 201-8Article in journal (Refereed) Published
Abstract [en]

The methane potential of forest residues was compared after applying organic solvent, i.e., acetic acid, ethanol, and methanol pretreatments using batch anaerobic digestion (AD). The pretreatments were performed at 190 °C with 50% (V/V) organic solvent for 60 min. The accumulated methane yields after 40 days of AD from pretreated forest residues were between 0.23 and 0.34 m3 CH4/kg VS, which shows a significant improvement compared to 0.05 m3 CH4/kg VS, from untreated forest residues. These improvements count up to 50% increase in the methane yields from the pretreated substrates based on expected theoretical yield from carbohydrates. Among the organic solvents, pretreatments with acetic acid and ethanol led to highest methane yields, i.e., over 0.30 m3 CH4/kg VS. However, techno-economical evaluation showed, pretreatment with methanol was more viable financially. The capital investments of the plant operating 20,000 tons of forest residues varied between 56 and 60 million USD, which could be recovered in less than 8 years of operation.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
anaerobic digestion, lignocelluloses, organosolv, pretreatments, process design
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-1894 (URN)10.1016/j.biortech.2014.07.064 (DOI)000347150700026 ()25113881 (PubMedID)2320/14037 (Local ID)2320/14037 (Archive number)2320/14037 (OAI)
Available from: 2015-11-13 Created: 2015-11-13 Last updated: 2018-11-29Bibliographically approved
Rajendran, K., Rajoli, S., Teichert, O. & Taherzadeh, M. J. (2015). Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics.. Bioprocess and biosystems engineering (Print), 38(2), 389-397
Open this publication in new window or tab >>Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics.
2015 (English)In: Bioprocess and biosystems engineering (Print), ISSN 1615-7591, E-ISSN 1615-7605, Vol. 38, no 2, p. 389-397Article in journal (Refereed) Published
Abstract [en]

More than half of the bioethanol plants in operation today use corn or grains as raw materials. The downstream processing of mash after fermn. to produce ethanol and distiller grains is an energy-demanding process, which needs retrofitting for optimization. In addn., the fluctuation in the ethanol and grain prices affects the overall profitability of the plant. For this purpose, a process simulation was performed in Aspen Plus based on an existing industrial plant located in Sweden. The simulations were compared using different scenarios including different concns. of ethanol, using the stillage for biogas prodn. to produce steam instead of distiller grains as a byproduct, and altering the purity of the ethanol produced. Using stillage for biogas prodn., as well as utilizing the steam, reduced the overall energy consumption by 40 % compared to the plant in operation. The fluctuations in grain prices had a high impact on the net present value (NPV), where grain prices greater than 349 USD/ton reached a zero NPV. After 20 years, the plant in operation producing 41,600 tons ethanol/yr can generate a profit of 78 million USD. Compared to the base case, the less purified ethanol resulted in a lower NPV of 30 million USD. [on SciFinder(R)]

Keywords
ethanol prodn retrofitting stillage biogas process simulation
National Category
Industrial Biotechnology
Identifiers
urn:nbn:se:hb:diva-91 (URN)10.1007/s00449-014-1278-2 (DOI)000349024000018 ()2-s2.0-84937869775 (Scopus ID)
Note

CAPLUS AN 2014:1500507(Journal; Online Computer File)

Available from: 2015-12-06 Created: 2015-05-22 Last updated: 2018-11-30Bibliographically approved
Rajendran, K. (2015). Industrial Bioprocess Developments for Biogas and Ethanol Production. (Doctoral dissertation). Borås: Högskolan i Borås
Open this publication in new window or tab >>Industrial Bioprocess Developments for Biogas and Ethanol Production
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Current biofuels face a noteworthy misfortune on commercialization because of its economiccomparison with low-cost fuel from the oil reserves. To compete with gasoline as a fuel, thebiofuels need to be economically feasible and demonstrated on a large-scale. Biogas and ethanolhave a great potential as commercial biofuels, even though it has difficulties, for example, highcapitalinvestment, absence of demonstrated innovations, and availability of raw materials and soforth. This thesis focuses on different application-driven bioprocess developments for improvingthe techno-economic feasibility of the biogas and ethanol industries.

The biogas industry was studied from three different perspectives:

1) Modeling approach in which a Process Simulation Model (PSM) model was developed forpredicting the biogas productions, as exploiting new substrates is vital for a biogas industrygrowth. The PSM model was created using Aspen Plus® which includes 46 reactions of differentphases in the Anaerobic Digestion (AD) processes. It also contains certain important processparameters, thermodynamics, rate-kinetics, and inhibitions involved in the AD processes. PSMwas a library model for the AD processes, which was validated against the laboratory andindustrial data. The validation showed that the PSM predicted the biogas production about 5% inexcess, which could ease the biogas industry to predict biogas from new substrates.

2) Simulation approach to study the imperative components affecting the profitability of theplant. For this purpose, a local municipality plant was studied under distinct situations. The choiceof upgrading method, capacity, cost of waste and its processing, number of digesters used, etc.were exploited. The results showed that the collection and transportation fee, landfilling fee, andthe reduced operation of a plant were the main considerations in influencing its profitability.Moreover, it was identified that for bigger cities the decentralization strategy could beat theexpense of collection and transportation of waste, and the plant could obtain a 17.8% return oninvestment.

3) Rethinking digester technology in which the cost of the digester was significantly lessenedusing a cutting-edge textile, which was principally intended for developing countries. The digestercost played an important role in consuming biogas for different applications. The textile digesterwas tested on a laboratory scale, followed by field tests in different countries including India,Indonesia, and Brazil. Textile digesters cost one-tenth of the conventional digesters, and thepayback was more or less between 1–3 years, when replacing the Liquefied Petroleum Gas (LPG)and kerosene as a cooking fuel for households.

When it comes to ethanol, the first generation ethanol production using grains was financiallypossible with a payback of about 13 years. Nonetheless, with the fluctuation of the oil prices, theethanol industries need to look for alternative sources of revenues. Different retrofits wereconsidered, including the effect of thin-stillage/whole-stillage to ethanol and biomass, in additionto the integration of the first and second generation ethanol production. The results revealed that4% additional ethanol could be obtained when the thin-stillage was converted into ethanol andfungal biomass, while the payback was reduced to 11.5 years. The integration of the first andsecond generation ethanol production revealed that it has a positive influence on the overalleconomics of the process with a payback of 10.5 years. This could help the ethanol industries toconsider a revamp for a better environmental, economic, and energy efficient process.

Place, publisher, year, edition, pages
Borås: Högskolan i Borås, 2015. p. 64
Series
Skrifter från Högskolan i Borås, ISSN 0280-381X ; 71
Keywords
biogas, ethanol, process design, techno-economic analysis, simulation, modeling
National Category
Environmental Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-668 (URN)978-91-87525-71-1 (ISBN)978-91-87525-72-8 (ISBN)
Public defence
2015-11-06, E310, Allegatan 1, Borås, 10:00 (English)
Available from: 2015-10-02 Created: 2015-08-25 Last updated: 2017-05-04Bibliographically approved
Aslanzadeh, S., Rajendran, K. & Taherzadeh, M. (2014). A comparative study between single- and two-stage anaerobic digestion processes: Effects of organic loading rate and hydraulic retention time. International Biodeterioration & Biodegradation, 95, 181-188
Open this publication in new window or tab >>A comparative study between single- and two-stage anaerobic digestion processes: Effects of organic loading rate and hydraulic retention time
2014 (English)In: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 95, p. 181-188Article in journal (Refereed) Published
Abstract [en]

The effect of an organic loading rate (OLR) and a hydraulic retention time (HRT) was evaluated by comparing the single-stage and two-stage anaerobic digestion processes. Wastes from the food processing industry (FPW) and the organic fraction of the municipal solid waste (OFMSW) were used as substrates. The OLR was increased at each step from 2 gVS/l/d to 14 gVS/l/d, and the HRT was decreased from 10 days to 3 days. The highest theoretical methane yield achieved in the single-stage process was about 84% for the FPW during an OLR of 3 gVS/l/d at a HRT of 7 days and 67% for the OFMSW at an OLR of 2 gVS/l/d and a HRT of 10 days. The single-stage process could not handle a further increase in the OLR and a decrease in the HRT; thus, the process was stopped. A more stable operation was observed at higher OLRs and lower HRTs in the two-stage system. The OLR could be increased to 8 gVS/l/d for the FPW and to 12 gVS/l/d for the OFMSW, operating at a HRT of 3 days. The results show a conclusion of 26% and 65% less reactor volume for the two-stage process compared to the single-stage process for the FPW and the OFMSW, respectively.

Place, publisher, year, edition, pages
Elsevier, 2014
Keywords
Resource Recovery
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-1890 (URN)10.1016/j.ibiod.2014.06.008 (DOI)2320/14033 (Local ID)2320/14033 (Archive number)2320/14033 (OAI)
Available from: 2015-11-13 Created: 2015-11-13 Last updated: 2017-12-01Bibliographically approved
Rajendran, K., Kankanala, H. R., Lundin, M. & Taherzadeh, M. J. (2014). A Novel Process Simulation Model (PSM) for Anaerobic Digestion Using Aspen Plus. Elsevier BV
Open this publication in new window or tab >>A Novel Process Simulation Model (PSM) for Anaerobic Digestion Using Aspen Plus
2014 (English)Other (Other academic)
Abstract [en]

A novel process simulation model (PSM) was developed for biogas production in anaerobic digesters using AspenPlus®. The PSM is a library model of anaerobic digestion, which predicts the biogas production from any substrate at any given process condition. A total of 46 reactions were used in the model, which include inhibitions, rate-kinetics, pH, ammonia, volume, loading rate, and retention time. The hydrolysis reactions were based on the extent of the reaction, while the acidogenic, acetogenic, and methanogenic reactions were based on the kinetics. The PSM was validated against a variety of lab and industrial data on anaerobic digestion. The P-value after statistical analysis was found to be 0.701, which showed that there was no significant difference between discrete validations and processing conditions. The sensitivity analysis for a ±10% change in composition of substrate and extent of reaction results in 5.285% higher value than the experimental value. The model is available at http://hdl.handle.net/2320/12358 (Rajendran et al., 2013b).

Place, publisher, year, pages
Elsevier BV, 2014
Keywords
Resursåtervinning
National Category
Engineering and Technology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-5381 (URN)10.1016/j.biortech.2014.01.051 (DOI)24524857 (PubMedID)2320/12358 (Local ID)2320/12358 (Archive number)2320/12358 (OAI)
Available from: 2015-12-17 Created: 2015-12-17 Last updated: 2016-05-13
Rajendran, K., Rajoli, S., Teichert, O. & Taherzadeh, M. J. (2014). Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics. Bioprocess and biosystems engineering (Print), 38(2)
Open this publication in new window or tab >>Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics
2014 (English)In: Bioprocess and biosystems engineering (Print), ISSN 1615-7591, E-ISSN 1615-7605, Vol. 38, no 2Article in journal (Refereed) Published
Abstract [en]

More than half of the bioethanol plants in operation today use corn or grains as raw materials. The downstream processing of mash after fermentation to produce ethanol and distiller grains is an energy-demanding process, which needs retrofitting for optimization. In addition, the fluctuation in the ethanol and grain prices affects the overall profitability of the plant. For this purpose, a process simulation was performed in Aspen Plus® based on an existing industrial plant located in Sweden. The simulations were compared using different scenarios including different concentrations of ethanol, using the stillage for biogas production to produce steam instead of distiller grains as a by-product, and altering the purity of the ethanol produced. Using stillage for biogas production, as well as utilizing the steam, reduced the overall energy consumption by 40 % compared to the plant in operation. The fluctuations in grain prices had a high impact on the net present value (NPV), where grain prices greater than 349 USD/ton reached a zero NPV. After 20 years, the plant in operation producing 41,600 tons ethanol/year can generate a profit of 78 million USD. Compared to the base case, the less purified ethanol resulted in a lower NPV of 30 million USD.

Place, publisher, year, edition, pages
Springer, 2014
Keywords
Resource Recovery
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-1929 (URN)10.1007/s00449-014-1278-2 (DOI)2320/14367 (Local ID)2320/14367 (Archive number)2320/14367 (OAI)
Available from: 2015-11-13 Created: 2015-11-13 Last updated: 2017-12-01Bibliographically approved
Aslanzadeh, S., Rajendran, K. & Taherzadeh, M. J. (2014). Pretreatment of Lignocelluloses for Biogas and Ethanol Processes. In: Ram Sarup Singh, Ashok Pandey, Christian Larroche (Ed.), Advances in Industrial Biotechnology: (pp. 125-150). Asiatech Publishers Inc
Open this publication in new window or tab >>Pretreatment of Lignocelluloses for Biogas and Ethanol Processes
2014 (English)In: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, Asiatech Publishers Inc , 2014, p. 125-150Chapter in book (Refereed)
Place, publisher, year, edition, pages
Asiatech Publishers Inc, 2014
Keywords
Resource Recovery
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-5222 (URN)2320/14207 (Local ID)9789382332763 (ISBN)2320/14207 (Archive number)2320/14207 (OAI)
Available from: 2015-12-17 Created: 2015-12-17 Last updated: 2016-06-21Bibliographically approved
Rajendran, K. & Taherzadeh, M. J. (2014). Pretreatment of Lignocellulosic Materials. In: V. Bisaria, A. Kondo (Ed.), Bioprocessing of Renewable Resources to Commodity Bioproducts: (pp. 43-76). Wiley
Open this publication in new window or tab >>Pretreatment of Lignocellulosic Materials
2014 (English)In: Bioprocessing of Renewable Resources to Commodity Bioproducts / [ed] V. Bisaria, A. Kondo, Wiley , 2014, p. 43-76Chapter in book (Refereed)
Place, publisher, year, edition, pages
Wiley, 2014
Keywords
Resource Recovery
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-5223 (URN)2320/14209 (Local ID)9781118175835 (ISBN)2320/14209 (Archive number)2320/14209 (OAI)
Available from: 2015-12-17 Created: 2015-12-17 Last updated: 2016-06-27Bibliographically approved
Rajendran, K. & Taherzadeh, M. (2014). Process Simulation Model for Biogas Production. Paper presented at Progress in Biogas III – Biogas production from agricultural biomass and organic residues, 10-11 September, 2014, Stuttgart, Germany. Paper presented at Progress in Biogas III – Biogas production from agricultural biomass and organic residues, 10-11 September, 2014, Stuttgart, Germany.
Open this publication in new window or tab >>Process Simulation Model for Biogas Production
2014 (English)Conference paper, Published paper (Refereed)
Keywords
biogas, process simulation, Biotechnology
National Category
Chemical Engineering
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-7316 (URN)2320/14621 (Local ID)978-3-940706-07-2 (ISBN)2320/14621 (Archive number)2320/14621 (OAI)
Conference
Progress in Biogas III – Biogas production from agricultural biomass and organic residues, 10-11 September, 2014, Stuttgart, Germany
Available from: 2015-12-22 Created: 2015-12-22 Last updated: 2016-03-03
Rajendran, K. & Taherzadeh, M. J. (2014). Techno-Economic Evaluation of an Industrial Biogas Plant. Paper presented at Green Gas Research Outlook Sweden, 24-25 mars, Gävle. Paper presented at Green Gas Research Outlook Sweden, 24-25 mars, Gävle.
Open this publication in new window or tab >>Techno-Economic Evaluation of an Industrial Biogas Plant
2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
Keywords
Biogas, Techno-economic analysis
National Category
Chemical Engineering Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-7171 (URN)2320/13549 (Local ID)2320/13549 (Archive number)2320/13549 (OAI)
Conference
Green Gas Research Outlook Sweden, 24-25 mars, Gävle
Available from: 2015-12-22 Created: 2015-12-22 Last updated: 2016-03-03
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