The production of biodiesel from waste cooking oil using microwave irradiation

Limited supply of petroleum resources, global warming issues and increasing yearly prices of petroleum in the present time, motivated scientists to find new alternative and cheap energy resources. Utilization of edible oil like vegetable oils as fuel actualized the competition between human needs in food and non -food applications. Also, the utilization of non-edible seed oils as renewable sources of fuel are costly due to the planting and production cost of the crude oils. In this study, the physical properties of crude palm oil (CPO), refined bleached deodorized (RBD) palm oil, waste cooking oil (WCO) and their methyl esters, has been investigated and characterized. Secondly, comparison was made using conventional method and microwave irradiation method of production of biodiesel, looking at different microwave exit powers, reaction time and reaction temperatures. The waste cooking oil (WCO) methyl ester characterization was done according to the ASTM method and was compared with published data. Generally, the flash point of this oil was reduced to 131ºC in its methyl ester form which is safe to be stored. Another result was the calorific value of the WCO methyl ester. It was 40,870 kJ/kg, which was slightly higher than its unprocessed form but still lower than diesel fuel. The cloud point and pour point of WCO methyl ester were lower than the CPO methyl ester but slightly higher than RBD methyl ester which are 13ºC and 9ºC respectively. The kinematic viscosity at 40ºC was 3.019 cSt, which was comparable with conventional diesel. Waste cooking oil’s density (0.886 kg/liter) was slightly higher than conventional diesel. The results showed that microwave irradiation decreases the reaction time dramatically from using conventional methods of 60 to 180 min to only 5 to 9 min

New insights into microwave pyrolysis of biomass: preparation of carbon-based products from pecan nutshells and their application in wastewater treatment

Microwave pyrolysis of pecan nutshell (Carya illinoinensis) biomass was used to produce carbon-based solid products with potential application in contaminated water treatment. A range of analytical techniques were applied to characterize the intermediate products of microwave pyrolysis in order to monitor the physio-chemical effects of the interacting energy on the biomass. The performance of the carbon-based products was tested through evaluation of lead ion removal capacity from solution. Further analyses demonstrated that ion-exchange by calcium ions on the material surface was the main mechanism involved in lead removal. Calcium compound development was directly correlated to the interaction of the electromagnetic waves with the biomass. Through monitoring the physio-chemical effects of biomass-microwave interactions during microwave pyrolysis, we have shown for the first time that the intermediate products differ from those of conventional pyrolysis. We hypothesise that selective heating leads to the (hemi)cellulosic and lignin degradation processes occurring simultaneously, whereas they are largely sequential in conventional pyrolysis. This work provides optimization parameters essential for the large scale design of microwave processes for this application as well as an understanding of how the operating parameters impact on functionality of the resulting carbon-based materials

Decarbonisation of olefin processes using biomass pyrolysis oil

An imperative step toward decarbonisation of current industrial processes is to substitute their petroleum-derived feedstocks with biomass and biomass-derived feedstocks. For decarbonisation of the petrochemical industry, integrated catalytic processing of biomass pyrolysis oil (also known as bio-oil) is an enabling technology. This is because, under certain conditions, the reaction products form a mixture consisting of olefins and aromatics, which are very similar to the products of naphtha hydro-cracking in the conventional olefin processes. These synergies suggest that the catalytic bio-oil upgrading reactors can be seamlessly integrated to the subsequent separation network with minimal retrofitting costs. In addition, the integrated catalytic processing provides a high degree of flexibility for optimization of different products in response to market fluctuations. With the aim of assessing the techno-economic viability of this pathway, five scenarios in which different fractions of bio-oil (water soluble/water insoluble) were processed with different degrees of hydrogenation were studied in the present research. The results showed that such a retrofit is not only economically viable, but also provides a high degree of flexibility to the process, and contributes to decarbonisation of olefin infrastructures. Up to 44% reductions in greenhouse gas emissions were observed in several scenarios. In addition, it was shown that hydrogen prices lower than 6 $/kg will result in bio-based chemicals which are cheaper than equivalent petrochemicals. Alternatively, for higher hydrogen prices, it is possible to reform the water insoluble phase of bio-oil and produce bio-based chemicals, cheaper than petrochemical equivalents

Integrated biorefineries: CO2 utilization for maximum biomass conversion

Biomass-derived fuels can contribute to energy sustainability through diversifying energy supply and mitigating carbon emissions. However, the biomass chemistry poses an important challenge, i.e., the effective hydrogen to carbon ratio is significantly lower for biomass compared to petroleum, and biomass conversion technologies produce a large amount of carbon dioxide by-product. Therefore, CO2 capture and utilization will be an indispensable element of future biorefineries. The present research explores the economic feasibility and environmental performance of utilizing CO2 from biomass pyrolysis for biodiesel production via microalgae. The results suggest that it is possible to increase biomass to fuel conversion from 55% to 73%. In addition, if subsidies and fuel taxes are included in the economic analysis, the extra produced fuel can compensate the cost of CO2 utilization, and is competitive with petroleum-derived fuels. Finally, the proposed integrated refinery shows promise as CO2 in the flue gas is reduced from 45% of total input carbon to 6% with another 19% in biomass residue waste streams

Microvawe pyrolysis of biomass: control of process parameters for high pyrolysis oil yields and enhanced oil quality

The oil yield and quality of pyrolysis oil from microwave heating of biomass was established by studying the behaviour of Larch in microwave processing. This is the first study in biomass pyrolysis to use a microwave processing technique and methodology that is fundamentally scalable, from which the basis of design for a continuous processing system can be derived to maximise oil yield and quality. It is shown systematically that sample size is a vital parameter that has been overlooked by previous work in this field. When sample size is controlled the liquid product yield is comparable to conventional pyrolysis, and can be achieved at an energy input of around 600 kWh/t. The quality of the liquid product is significantly improved compared to conventional pyrolysis processes, which results from the very rapid heating and quenching that can be achieved with microwave processing. The yields of Levoglucosan and phenolic compounds were found to be an order of magnitude higher in microwave pyrolysis when compared with conventional fast pyrolysis. Geometry is a key consideration for the development of a process at scale, and the opportunities and challenges for scale-up are discussed within this paper

The role of an exergy-based building stock model for exploration of future decarbonisation scenarios and policy making

State-of-the-art research suggests that energy systems are best evaluated using exergy analysis, as exergy represents the real value of an energy source, demonstrating it to be the only rational basis for evaluation. After discovering the lack of thermodynamic integration into stock modelling, this paper presents the development of an exergy-based building stock model. The aim of this paper is twofold. Firstly, to investigate the impact of large-scale future energy retrofit scenarios in the English and Welsh (E&W) non-domestic sector, and secondly, to determine the potential of exergy analysis in improving sectoral efficiency and its potential implications on exergy-oriented policy making. The research explores seven different large-scale future retrofit scenarios that encompass typical, low-carbon, and low-exergy approaches. Modelling results show that by 2050, current regulations have the potential to reduce carbon emissions by up to 49.0±2.9% and increasing sector thermodynamic efficiency from 10.7% to 13.7%. On the other hand, a low-exergy oriented scenario based on renewable electricity and heat pumps is able to reduce carbon emissions by 88.2±2.4%, achieving a sectoral exergy efficiency of 19.8%. This modelling framework can provide energy policy makers with new insights on policy options based on exergy indicators and the assessment of their potential impact