Blockchain adoption for sustainable supply chain management : economic, environmental, and social perspectives

Due to the rapid increase in environmental degradation and depletion of natural resources, the focus of researchers is shifted from economic to socio-environmental problems. Blockchain is a disruptive technology that has the potential to restructure the entire supply chain for sustainable practices. Blockchain is a distributed ledger that provides a digital database for recording all the transactions of the supply chain. The main purpose of this research is to explore the literature relevant to blockchain for sustainable supply chain management. The focus of this review is on the sustainability of the blockchain-based supply chain concerning environmental conservation, social equality, and governance effectiveness. Using a systematic literature review, a total of 136 articles were evaluated and categorized according to the triple bottom-line aspects of sustainability. Challenges and barriers during blockchain adoption in different industrial sectors such as aviation, shipping, agriculture and food, manufacturing, automotive, pharmaceutical, and textile industries were critically examined. This study has not only explored the economic, environmental, and social impacts of blockchain but also highlighted the emerging trends in a circular supply chain with current developments of advanced technologies along with their critical success factors. Furthermore, research areas and gaps in the existing research are discussed, and future research directions are suggested. The findings of this study show that blockchain has the potential to revolutionize the entire supply chain from a sustainability perspective. Blockchain will not only improve the economic sustainability of the supply chain through effective traceability, enhanced visibility through information sharing, transparency in processes, and decentralization of the entire structure but also will help in achieving environmental and social sustainability through resource efficiency, accountability, smart contracts, trust development, and fraud prevention. The study will be helpful for managers and practitioners to understand the procedure of blockchain adoption and to increase the probability of its successful implementation to develop a sustainable supply chain network

Waste-integrated biorefineries : A path towards efficient utilization of waste

Waste-management systems have progressed from landfilling and dumping to waste prevention, recycling and resource recovery. In state-of-the-art waste-management industries, waste is separated into various fractions and treated with suitable processes. The non-recyclable organic fraction of waste can be incinerated for combined heat and power (CHP) production, while biodegradable waste can be converted to biomethane through the anaerobic digestion (AD) process. Thermochemical processes such as gasification and pyrolysis provide alternative methods for treating various fractions of waste. This thesis aims to design energy-efficient and cost-effective waste-integrated biorefineries by integrating thermochemical processing of waste with existing WtE technologies. A system analysis of five process-integration case studies have been performed. The first case assesses the limitations and operational limits of thermochemical processes retrofitted in an existing waste-based CHP plant. The second and third case studies evaluate the feasibility of the current waste-based CHP plant to shift from cogeneration to polygeneration of biofuels, heat and power. In the fourth case study, a new process configuration is presented that couples AD of biodegradable waste with pyrolysis of lignocellulosic waste. The last case deals with the handling of digested sludge from WWTPs by the integration of thermochemical processes. The findings suggest that waste-integrated biorefineries can utilize infrastructure and products from existing waste industries through process integration and improve the overall process efficiencies and economics. Existing waste-based CHP plants can provide excess heat for integrated thermochemical processes; however, the modifications required are different for different gasifiers and pyrolyzers. Similarly, refuse-derived fuel (RDF) — processed from municipal solid waste (MSW) — can be utilized for production of various biofuels alongside heat and power without disturbing the operation of the CHP. But biomethane and dimethyl ether (DME) showed higher process feasibility than methanol and drop-in biofuels. The integration of pyrolysis with the AD process can almost double biomethane production compared with a standalone AD process, increasing efficiency to 67% from 52%. The integration is an attractive investment when off-site — rather than on-site — integration of pyrolysis and AD is considered. Drying of sludge digestate from wastewater treatment plants (WWTPs) is a bottleneck for its post-processing by thermochemical processes. However, waste heat from the existing CHP plant can be utilized for drying of sludge, which can also replace some of the boiler feed through co-incineration with waste biomass. The economic performance of waste-integrated biorefineries will depend on the volatility of market conditions. Finally, assessment of the effects of uncertainty of input data and process parameters on metrics of technical and economic performance is vital for evaluation of overall system performance

Production of biodiesel from waste vegetable oil

In the present project technological and economical aspects of biodiesel was studied, in first part of project bio diesel was synthesized from Waste vegetable Oil (WVO) by three-step method and regressive analyzes of the process was done. The raw oil was collected from local restaurant of Barcelona city in Spain. In the three-step method, the first step is saponification of the oil followed by acidification to produce FFA and finally esterification of FFA to produce biodiesel. In the saponification reaction, various reaction parameters such as oil to sodium hydroxide molar ratio and reaction time were optimized and the oil to NaOH molar ratio was 1:2, In the esterification reaction, the reaction parameters such as methanol to FFA molar ratio, catalyst concentration and reaction temperature were optimized Finally HHV of biodiesel was measured and compared with biodiesel and petro-diesel standard. It was found almost equal to petro diesel produced by National Refinery of Pakistan i.e. 40000 KJ/Kg. In second part detailed market survey was done in restaurants in order to check the supply of raw material and need of the targeted market and then detailed economical analysis was also done in order to check the feasibility of the project in the target market in Pakistan. The market is not saturated and there is a need of the product but initial capital investment found is higher and investors will have to wait for the revenues.QC 20201118</p

Production of biodiesel from waste vegetable oil

In the present project technological and economical aspects of biodiesel was studied, in first part of project bio diesel was synthesized from Waste vegetable Oil (WVO) by three-step method and regressive analyzes of the process was done. The raw oil was collected from local restaurant of Barcelona city in Spain. In the three-step method, the first step is saponification of the oil followed by acidification to produce FFA and finally esterification of FFA to produce biodiesel. In the saponification reaction, various reaction parameters such as oil to sodium hydroxide molar ratio and reaction time were optimized and the oil to NaOH molar ratio was 1:2, In the esterification reaction, the reaction parameters such as methanol to FFA molar ratio, catalyst concentration and reaction temperature were optimized Finally HHV of biodiesel was measured and compared with biodiesel and petro-diesel standard. It was found almost equal to petro diesel produced by National Refinery of Pakistan i.e. 40000 KJ/Kg. In second part detailed market survey was done in restaurants in order to check the supply of raw material and need of the targeted market and then detailed economical analysis was also done in order to check the feasibility of the project in the target market in Pakistan. The market is not saturated and there is a need of the product but initial capital investment found is higher and investors will have to wait for the revenues.QC 20201118</p

TECHNO-ECONOMIC ANALYSIS OF WOOD PYROLYSIS IN SWEDEN

The significance of bio fuels production is increasing as fossil fuels are being depleted and energy security is gaining importance in the final energy mix. Moreover, bio fuel production offers the potential to alleviate concerns regarding global warming and air pollution. The process scheme design and parameter value choices used in this analysis are exclusively based on research domain literature by considering the state of the art of pyrolysis technology. Henceforth, the results should not be interpreted as optimal performance of mature technology, but as the most likely performance given the current state of scientific knowledge. The purpose of this thesis is to study and assess the technical and economic models for the conversion of woody biomass to valuable biofuel products via fast pyrolysis. The mass rate of wood is considered as 100,000 t/y. Bio fuel production from pyrolysis is energy intensive process. Therefore, heat and energy requirement calculation for the process and optimum heat integration is necessary to improve the overall thermodynamic efficiencies for wood biomass pyrolysis. Three different cases are discussed in this thesis: 1. fast pyrolysis at 500 oC, 2. fast pyrolysis at 1000 oC   and 3. Slow pyrolysis at 500 oC.    Literature study was conducted for different pyrolysis processes and based on their findings and results a model was developed on excel for the calculation of mass and energy balance. Mass balance results shows that the process can be selected on the basis of final product required. It was found that fast pyrolysis at 500 oC is used when bio oil is the priority product, for maximizing the syngas yield fast pyrolysis at high temperature 800-1000 oC is preferred. Similarly slow pyrolysis is used for maximizing bio char yield. It was also found that raw material type and its pretreatment also has strong influence on the pyrolysis process and final composition of bio fuels. Heat flux and energy streams for the pyrolysis scheme are also designed and syngas was selected to fulfil the heat requirements for different processes alongside with pyrolysis such as drying and grinding. It was found out that syngas combustion and heat recovery from the condenser will be able to fulfill the heat demand for pyrolysis process. However the specific heat requirement for fast and slow pyrolysis process varies. According to the calculations heat flux requirement for slow pyrolysis is higher than the fast pyrolysis. An explanation for this variability of the heat for wood pyrolysis is exothermic primary char formation process competing with an endothermic volatile formation process which makes it as overall endothermic process. But pretreatment of wood or biomass in fast pyrolysis is extra burden on the total heat demand for fast pyrolysis. Economic assessment for the pyrolysis plants is also conducted through literature survey of already installed plants and it was found out that pyrolysis is more feasible for large production facilities. The trends shows that capital costs increase with the increase of plant size but the capital cost curve moves towards a straight line after reaching the certain value the production cost per gallon of bio fuel decreases with the increase of plant capacity. The cost of biofuel is extremely sensitive to variations in operating cost (for example, cost of feed stock such as wood and selling price of products) but is not significantly affected by the variations in capital cost

Integration of thermochemical processes with existing waste management industries to enhance biomethane production

In most waste management industries, waste is separated into different fractions, each of which is treated with suitable processes. Established technologies such as waste combustion for combined heat and power (CHP) production and biomethane production through anaerobic digestion (AD) of biodegradable waste work fine as standalone processes. However, specific issues are associated with these established standalone waste-to-energy (WtE) processes. For example, traditional CHP plants have high overall energy efficiencies, but lower electrical efficiencies, and their heat outputs are dependent on local demand and seasonal variations. Similarly, biodegradable waste typically sent for AD contains lignocellulosic or green waste. Due to the lower biodegradability of lignocellulosic waste, only a proportion is sent for digestion, while the rest is incinerated, increasing transportation costs. Increased benefits from the perspective of energy and economics can be achieved by integrating new WtE processes with existing technologies.   This thesis aims to design energy-efficient and profitable biorefineries by integrating existing waste management facilities with the thermochemical treatment of waste. A systems analysis of two process integration concepts has been studied through modelling and simulation. The first analysis is of the process integration of gasification with existing CHP plants, and the second is the process integration of pyrolysis with an existing AD plant. For integration of gasification with a CHP plant, reasonable operational limits of the CHP plant have been assessed and compared by integrating three types of gasifier, and the most technically and economically integrated processes have been identified. In the case of integration of pyrolysis with AD, a new process configuration is presented that couples the AD of biodegradable waste with the pyrolysis of lignocellulosic waste. The biochar obtained from pyrolysis is added to a digester as an adsorbent to increase the biomethane production. In addition, the vapors produced by the pyrolysis process are converted to biomethane. Two different conversion processes are compared to convert pyrolysis vapors to biomethane, catalytic methanation and biomethanation.    The results demonstrate that process integration can contribute to reducing the cost of biomethane production through integration of gasification and pyrolysis with CHP and AD, respectively. The process integration can also utilize infrastructure and products from existing industries and increase the overall process efficiencies. Of the gasifiers studied, the dual fluidized bed gasifier produces more biomethane than the circulating bed and entrained flow gasifiers when retrofitted with an existing CHP plant with up to 85% efficiency. The CHP–gasification integration is capable of producing more biomethane during low heat demand seasons without disturbing the operation of the CHP operation. A gasifier with a flexible capacity can be integrated with the CHP to produce biomethane without affecting the heat production of the CHP. From an economic perspective, the dual-bed gasifier requires lower capital investment and is therefore more profitable, because it requires less equipment than the circulating fluidized and entrained flow gasifiers. The integration of pyrolysis with the AD process can almost double biomethane production comparison with standalone AD process, increasing efficiency to 67%. The integration is an attractive investment when catalytic methanation of syngas is used rather than biomethanation of syngas. The catalytic methanation route has an economic rate of return of 16%, with a six-year payback period.   The main conclusion drawn from this thesis is that production of biomethane can be enhanced through process integration of gasification with the CHP plant and of pyrolysis with AD. However, the increase in biomethane production also increases the demand for waste at the integrated biorefinery. Hence, the capacity of the gasifier and pyrolysis process will be decisive in determining the level of integration of the biorefineries.I de flesta avfallshanteringsanläggningarna separeras avfallet i olika fraktioner och behandlas i lämpliga processer. Etablerade tekniker som förbränning av avfall för kombinerad el- och värmeproduktion och produktion av biometan genom rötning (AD) av biologiskt nedbrytbart avfall fungerar bra som fristående processer. Det finns dock några nackdelar med de etablerade processerna för omvandling av avfall till energi (WtE), t ex har traditionella kraftvärmeverk höga energiverkningsgrad, men lägre elverkningsgrad och värmproduktionen är beroende av lokal efterfrågan och säsongsvariationer. På liknande sätt innehåller biologiskt nedbrytbart avfall som används till rötning, lignocellulosa eller eller så kallat grönavfall. På grund av lägre biologisknedbrytningav avfall med lignocellulos används endast en del av detta för rötning medan resten förbränns, vilket ökar transportkostnaderna. Större fördelar med avseende på energi och ekonomi kan uppnås genom att integrera de nya WtE-processerna med befintlig teknik.   Avhandlingen syftar till att utforma energieffektiva och kostnadseffektiva bioraffinaderier genom att integrera befintliga avfallshanteringsanläggningar med termokemisk behandling av avfall. En systemanalys av två processintegrationskoncept har studerats genom modellering och simulering. En är processintegrering av förgasning med befintliga kraftverk, och den andra är integrationen av pyrolys med befintliga rötningsanläggningar. För integration av kraftvärme och förgasning utvärderas rimliga gränser för sdriften av en anläggning genom att jämföra integreration av tre typer av förgasare och den tekniskt och ekonomiskt bästa integrerade processen identifieras. För integrering av pyrolys och rötning presenteras en ny processkonfiguration som kopplar rötning av biologiskt nedbrytbart avfall med pyrolys av avfall som innehåller lignocellulosl. Biokol från pyrolysen tillsätts rötkammaren som en adsorbent för att öka biometanhalten. Dessutom omvandlas de ångor som framställs genom pyrolysprocessen till biometan. Två olika omvandlingsprocesser för att konvertera pyrolysångor till bio-metan jämförs, dvs katalytisk metanisering och biometanisering.   Resultaten visar att processintegration kan bidra till att minska produktionskostnaderna för biometan genom förgasning och pyrolys genom integration med kraftvärme (CHP) respektive rötning (AD). Processintegrationen kan också utnyttja infrastrukturen och produkterna från befintliga industrier och öka den totala processeffektiviteten. Av alla undersökta förgasare producerar indirekt förgasning mer biometan jämfört med cirkulerande bädd och flödesförgasare när den integreras med ett befintligt kraftvärmeverk, med upp till 85 % verkningsgrad. Integreringen av kraftvärme och förgasning kan producera mer biometan under säsonger med låg efterfrågan av värme, utan att störa kraftvärme-driften. När det gäller förgasningsstorleken kan förgasarens flexibla kapacitet integreras med kraftvärme för att producera biometan utan att ändra den årliga värmeproduktionen. Ur ett ekonomiskt perspektiv kräver indirekta förgasaren lägre kapitalinvesteringar och ger högre intäkter på grund av färre utrustningsdelar än cirkulerande fluidiserad förgasare och flödesförgare. Integreringen av pyrolys med rötnings-processen kan nästan dubbla bio-metanproduktionen och öka verkningsgraden till 67 %. Integrationen är attraktiv för investering när katalytisk metanisering används istället för biometanisering av syngas. Katalytisk metanisering ger en avkastning på 16 %, med sex års återbetlaningstid.   Den viktigaste slutsatsen från denna avhandling är att produktionen av bio-metan kan förbättras genom processintegration av förgasning med kraftvärm och pyrolys med rötning. Ökningen av bio-metanproduktion ökar emellertid även efterfrågan på avfall till integrerade bioraffinaderier. Därför kommer storleken av förgasare och pyrolysprocessen att vara avgörande för att bestämma integrationsnivån av de studerade bioraffinaderierna

Production of biodiesel from waste vegetable oil

In the present project technological and economical aspects of biodiesel was studied, in first part of project bio diesel was synthesized from Waste vegetable Oil (WVO) by three-step method and regressive analyzes of the process was done. The raw oil was collected from local restaurant of Barcelona city in Spain. In the three-step method, the first step is saponification of the oil followed by acidification to produce FFA and finally esterification of FFA to produce biodiesel. In the saponification reaction, various reaction parameters such as oil to sodium hydroxide molar ratio and reaction time were optimized and the oil to NaOH molar ratio was 1:2, In the esterification reaction, the reaction parameters such as methanol to FFA molar ratio, catalyst concentration and reaction temperature were optimized Finally HHV of biodiesel was measured and compared with biodiesel and petro-diesel standard. It was found almost equal to petro diesel produced by National Refinery of Pakistan i.e. 40000 KJ/Kg. In second part detailed market survey was done in restaurants in order to check the supply of raw material and need of the targeted market and then detailed economical analysis was also done in order to check the feasibility of the project in the target market in Pakistan. The market is not saturated and there is a need of the product but initial capital investment found is higher and investors will have to wait for the revenues.QC 20201118</p

Process Modelling and Simulation of Waste Gasification-Based Flexible Polygeneration Facilities for Power, Heat and Biofuels Production

There is increasing interest in the harnessing of energy from waste owing to the increase in global waste generation and inadequate currently implemented waste disposal practices, such as composting, landfilling or dumping. The purpose of this study is to provide a modelling and simulation framework to analyze the technical potential of treating municipal solid waste (MSW) and refuse-derived fuel (RDF) for the polygeneration of biofuels along with district heating (DH) and power. A flexible waste gasification polygeneration facility is proposed in this study. Two types of waste—MSW and RDF—are used as feedstock for the polygeneration process. Three different gasifiers—the entrained flow gasifier (EFG), circulating fluidized bed gasifier (CFBG) and dual fluidized bed gasifier (DFBG)—are compared. The polygeneration process is designed to produce DH, power and biofuels (methane, methanol/dimethyl ether, gasoline or diesel and ammonia). Aspen Plus is used for the modelling and simulation of the polygeneration processes. Four cases with different combinations of DH, power and biofuels are assessed. The EFG shows higher energy efficiency when the polygeneration process provides DH alongside power and biofuels, whereas the DFBG and CFBG show higher efficiency when only power and biofuels are produced. RDF waste shows higher efficiency as feedstock than MSW in polygeneration process

Process simulation and comparison of biological conversion of syngas and hydrogen in biogas plants

Organic waste is a good source of clean energy. However, different fractions of waste have to be utilized efficiently. One way is to find pathways to convert waste into useful products via various available processes (gasification, pyrolysis anaerobic digestion, etc.) and integrate them to increase the combined efficiency of the process. The syngas and hydrogen produced from the thermal conversion of biomass can be upgraded to biomethane via biological methanation. The current study presents the simulation model to predict the amount of biomethane produced by injecting the hydrogen and syngas. Hydrogen injection is modelled both in-situ and ex-situ while for syngas solely the ex-situ case has been studied. The results showed that 85% of the hydrogen conversion was achieved for the ex-situ reactor while 81% conversion rate was achieved for the in-situ reactor. The syngas could be converted completely in the bio-reactor. However, the addition of syngas resulted in an increase of carbon dioxide. Simulation of biomethanation of gas addition showed a biomethane concentration of 87% while for hydrogen addition an increase of 74% and 80% for in-situ and ex-situ addition respectively

A polygeneration process for heat, power and DME production by integrating gasification with CHP plant : Modelling and simulation study

Biofuels are a good substitute for the transport sector petroleum fuels to minimize carbon footprint and greenhouse gases emissions. Di-Methyl Ether (DME) is one such alternative with properties similar to liquefied petroleum gas but with lower SOx, NOx, and particulate emissions. In this work, a polygeneration process, integrating an existing combined heat and power (CHP) plant with biomass gasification to synthesize DME, is proposed and modelled. Process integration is based on a hypothesis that the CHP plant provides the necessary heat to run the co-located gasification plant for DME synthesis and the waste heat from the gasification process is recovered and transferred to the CHP plant. The feed for gasification is taken as refuse derived fuel (RDF) instead of conventional wood derived biomass. The process integration leads to higher overall combined efficiency (up to 71%) which is greater than stand-alone efficiencies (up to 63%) but lower than stand-alone CHP plant efficiency (73.2%). The further technical evaluation shows that the efficiency of the polygeneration process is depends heavily on the gasifier capacity integrated with the existing CHP plant and also on the conversion route selected for DME synthesis i.e. recycling of unconverted syngas to the DME reactor or transferring it to the boiler of the CHP plant. The simulation results also indicate that once-through conversion yields less DME than recycling, but at the same time, once-through conversion affects the district heat and electric power production of the CHP plant lesser than by using the recycling route