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Rubber seed oil (RSO) (Hevea brasiliensis) was extracted from rubber seeds by chemical means. The effect of temperature on the oil yield was investigated. The experiment suggested that the maximum yield of the oil occurs at 60 °C. This is a result of the proximity to the boiling point of n-hexane, which is about 68 °C. Epoxidized and hydroxylated RSOs were further synthesized by performic acid generated in situ by the reaction of formic acid with 30% hydrogen peroxide. The physiochemical properties of the epoxidized rubber seed oil (ERSO) and hydroxylated rubber seed oil (HRSO) were determined. A separate study was also carried out on castor seed oil (CSO). The improved products were characterized with respect to their configuration and properties. Spectroscopic analysis was carried out on the oil base stocks (RSO, CSO, ERSO, and HRSO). All of the experimental findings were compared with one another. The lubricating properties of CSO and HRSO are further studied as a result of their common hydroxyl nature to ascertain their suitability as a lubricant base. Both oils can be categorized as a nondrying oil with saponification values of 179.52 and 255.25 mgKOH/g, respectively, and as such possess advantageous properties for industrial application. When compared to one another, HRSO appears to be a more effective choice as a lubricant base. This is because of its higher viscosity index of 380.65. The outcomes of this study indicate that hydroxylated and epoxidized RSO with high oxirane content can be synthesized concurrently by one-pot multistep reactions.

Adequate supply of electricity at a competitive price is pivotal to sustainable development. More often than not, the generation of electricity which drives modern growth and development is currently powered by limited fossil fuels in many nations. Electricity generation and megawatt demand are also usually fluctuating due to several pertinent factors. In a bid to articulate the impact of inherent variations in process parameters on the performance of steam power plant at different loads, this paper presents an investigation into the efficacy of two validation strategies in predicting the net power output from the plant using GMDH Shell software. Using the combinatorial algorithm, the k-fold cross-validation strategy and the training/testing validation technique were applied to empirical data of a power plant in Nigeria. The performance of the models returned from the two validation strategies was evaluated using maximum negative error, maximum positive error, mean absolute percentage error (MAPE), root mean square percentage error (RMSPE), residual sum, the standard deviation of residuals, coefficient of determination (R2) and correlation. For the number of folds and the training/testing split percentage considered in this study, results show that both models obtained were quite competitive, with the k-fold model having a slight edge over the other model. It is expected that the outcome of the study will be handy in researches for providing knowledge base information on choosing and setting optimum operating conditions at various load demand.

Industrial activities, including the process of power generation from thermal plants, are inevitably associated with the generation of gaseous wastes and particulate matters. Industrial activities, therefore, contribute largely to the emission of environmental pollutants. In addition to causing environmental degradation, the emission of pollutants, particularly greenhouse gases, have far-reaching social negative externalities, mainly in the area of unconducive temperature rise and adverse climatic impact. The unintended impacts of industrial emissions have motivated the development of plans and strategies for their abatement. In this study, predictive models of the global warming potential and carbon tax of the gaseous emission at various fuel consumption levels and different air–fuel ratio for the combustion process in a thermal power plant were developed. It is expected that the models serve as a veritable tool for projecting the environmental & economic costs of natural gas burning and optimizing the process of the fuel combustion for lower greenhouse gas emissions.

It is crystal clear that appropriate technical sizing has a significant effect on the techno-economic analysis of an off-grid standalone energy system. As a result, this study presents the effect of incorporating the temperature coefficient in the optimal analysis of an off-grid hybrid system using a standard fuel (gas) station in Nigeria as a case study. Comparative analysis with and without the temperature coefficient was performed. The results showed that the inclusion of temperature coefficient leads to extra operation hours of the generator which will result in an increase in fuel consumption and annual operation cost of the diesel generator. Also, the initial cost of the PV/BAT/diesel is relatively higher than the diesel generator but, the generating emission of the hybrid system is lower when compared to the diesel-only which enhances the atmospheric condition of the society.Keywords: Techno-economic Analysis, Hybrid System, Temperature Coefficient, Fuel ConsumptionJEL Classifications: Q4, Q43DOI: https://doi.org/10.32479/ijeep.9886

Adoption of energy efficiency and conservation techniques in public buildings in Nigeria is significantly low due to the ignorance of its potential benefits. Consequently, this study presents the prospects of energy saving using different methods in a public building at a Nigerian University. A proposed remodelled students’ residential hostel at the University of Lagos, Nigeria was chosen as a pilot study. This research utilized three energy efficient lighting technology alternatives namely; intelligent controlled Incandescent lamp (ICIL), compact fluorescent lamp (CFL), and intelligent controlled CFL (ICCFL) and compared with a base case of conventional incandescent lighting configuration. Energy consumption, at the proposed hostel is analysed and modelled. The effectiveness of each lighting technology alternative and base case in terms of cost is estimated using economic indices such as the net present value (NPV), savings to investment ratio (SIR) and the discounted payback period (DPP). Results show that the CFL lighting technology give 39% cost benefit as compared to ICCFL which gives 11% overall cost benefit. From the study, it is established that adoption of energy efficient lighting techniques save a significant amount of energy, operational cost, electricity bills and consequently reduce emission.Keywords: Energy saving, Net present value, Savings to investment ratio, discounted payback periodJEL Classifications: C63, Q48DOI: https://doi.org/10.32479/ijeep.9905

Electricity supply in Nigeria is a huge problem with great economic and political consequences. After unbundling and privatization of generation and distribution companies, not much improvement has been experienced by electricity consumers; this is due to lack of investment in infrastructure. Lack of investment in infrastructure especially from private investors is caused largely by non-cost reflective tariff among other factors highlighted in this study. While many believe tariff has to be controlled such that it does not go beyond the reach of average citizens, many also believe that the average citizens can pay much more than the current tariff. The latter is evident considering the average amount spend on the use of portable gasoline generators by most homes and small enterprises both in rural and urban centers. The whole life cost method is used to show here that it costs a home or business premise that operates a portable gasoline generator for 6 hours daily NGN 37, 000 per month and costs NGN 157,000 to operate 20 kVA diesel generator. This shows the consumers’ capacity to pay the appropriate tariff that can attract investors to the sector.Keywords: Utility, tariff, electric power generation cost, life cost method, consumerJEL Classification: Q43DOI: https://doi.org/10.32479/ijeep.8590

In order to realize the goal of optimal use of energy sources and cleaner environment at a minimal cost, researchers; field professionals; and industrialists have identified the expediency of harnessing the computational benefits provided by artificial intelligence techniques. This article provides an overview of artificial intelligence (AI), chronological blueprints of the emergence of artificial neural networks (ANNs) and some of its applications in the energy sector. This short survey reveals that despite the initial hiccups at the developmental stages of artificial neural networks, ANN has tremendously evolved, is still evolving and have been found to be effective in handling highly complex problems even in the areas of modeling, control, and optimization, to mention a few.Keywords: artificial neural networks, energy sector, optimizationJEL Classifications: Q4, P28DOI: https://doi.org/10.32479/ijeep.8691

Purpose This study aims to analyze the effects of variations in annual real interest rates in the assessment of the techno-economic feasibility of a hybrid renewable energy system (HRES) for an off-grid community. Design/methodology/approach Hybrid Optimization of Multiple Energy Resources (HOMER) software is used to propose an HRES for Abadam community in northern Nigeria. The HRES was designed to meet the basic needs of the community over a 25-year project lifespan. Based on the available energy resources in the community, photovoltaic (PV), wind turbine, diesel generator and battery were suggested for integration to serve the load requirements. Findings When the annual real interest rates were taken as 10 and 8 per cent, the total amount of total energy fraction from PV, wind turbine and the diesel generator is 28, 57 and 15 per cent, respectively. At these interest rates, wind turbines contributed more energy across all months than other energy resources. The energy resource distribution for 0, 2,4 and 6 per cent annual real interest rates have a similar pattern, but PV contributed a majority of the energy. Practical implications This study has used annual real interest and inflation rates dynamic behavior to determine optimal HRES for remote communities. Hence, its analysis will equip decision-makers with the necessary information for accurate planning. Originality/value The results of this study can be used to plan and design HRES infrastructure for off-grid communities around the world.

The 2030 Agenda for Sustainable Development suggests that all countries both developed and developing strive to attain the seventeen sustainable development goals (SDGs). Some items on the SDGs like implementation of renewable energy technologies to electrify regions disconnected from power grids are targeted to eradicate extreme poverty and hunger while ensuring environmental sustainability. Hence, the role of integrated renewable energy in improving the productivity and environmental sustainability of the agricultural sector cannot be overemphasized. This paper presents a brief survey of the application of renewable energy resources technologies in the agricultural sector. Keywords: Sustainable agriculture; Water-food-energy nexus; Renewable energy; Techno-economic.JEL Classifications: Q2, Q4DOI: https://doi.org/10.32479/ijeep.7775

Presented in this study is an optimal hybrid renewable off‐grid energy system model that supplies a typical rural healthcare center across the six regions in Nigeria. A technical and economic evaluation was carried out to identify the optimal off‐grid hybrid energy system combination based on photovoltaic (PV), wind, diesel generator and battery. Due to governments’ fuel subsidy in many developing countries, the pump price of fuel is reduced and not a true reflection of what is obtainable in a deregulated market. In order to comprehensively capture the reality, the study considered the effect of subsidy removal by carrying out a sensitivity analysis on the fuel pump price. Therefore, the impact of a change in diesel fuel pump price and interest rates on the economic performance criteria of the optimal configuration is explored. Results show that across all the locations considered, PV/diesel/battery system is the most economically viable with a net present cost and renewable fraction (RF) ranging between $12 779 and $13 646 and 70%‐80% respectively. The cost of energy (COE) is also estimated to range between 0.507 and 0.542 $/kWh.

The automotive industry is one major sector that consume material such as plastic at the advanced technological level. Hence, automotive plastics are now gaining attention due to the desire for light weight and low CO2 emission from vehicles. It is therefore anticipated that polymer nanocomposites will significantly enhance the performance of current technologies for car industries due to their excellent mechanical, chemical, thermal, electrical and barrier properties and their influence on fire retardancy. Hence, with the use of polymer nanocomposites, the encouraging outcomes in different sectors of automotive industry has resulted to new horizons in terms of advanced polymer nanocomposites for automobile applications. This chapter reviews advance polymer composites for automobile applications. Methods of fabricating polymer nanocomposites and several applications of polymer nanocomposites in automotive industries are discussed.

Mining is very vital to the production of goods, services and infrastructure; it advances the quality of lives in the society. However, the possible hazard of waste and radioactivity generated by mining, dumping and tailing, has called on the society to find ways of seeking remedy that will adequately treat mining waste from mine dump, tailing and abandoned mine. Mine waste reuse and recycling in mining industries could offer cost-effective benefits through offsetting raw material requirements and decreasing the volumes of waste to be managed. This review discussed mine dump pollution monitoring and mine dump management strategies for some selected countries. Impact and mechanism of mine damage to the environment was discussed together with the remediation principles. It further examines the mining Act and regulations of the same selected countries. Emphasised was placed on the enforcement of environmental laws, regulations, and standards. Practical ways in which country’s state authority and civil society can keep a close watch and enhance the enforcement of laws and regulations were highlighted. The prediction for the control of mineral exploration and environmental assessment was also discussed for executing a specific control to take preventive measures. Management techniques used in combating the impact of mine dump, stockpiles and tailing on the environment were discussed. In addition, radioactivity in mine and its monitoring and control was discussed.

Rubber seed oil (RSO) (Hevea brasiliensis) was extracted from rubber seeds by chemical means. The effect of temperature on the oil yield was investigated. The experiment suggested that the maximum yield of the oil occurs at 60 °C. This is a result of the proximity to the boiling point of n-hexane, which is about 68 °C. Epoxidized and hydroxylated RSOs were further synthesized by performic acid generated in situ by the reaction of formic acid with 30% hydrogen peroxide. The physiochemical properties of the epoxidized rubber seed oil (ERSO) and hydroxylated rubber seed oil (HRSO) were determined. A separate study was also carried out on castor seed oil (CSO). The improved products were characterized with respect to their configuration and properties. Spectroscopic analysis was carried out on the oil base stocks (RSO, CSO, ERSO, and HRSO). All of the experimental findings were compared with one another. The lubricating properties of CSO and HRSO are further studied as a result of their common hydroxyl nature to ascertain their suitability as a lubricant base. Both oils can be categorized as a nondrying oil with saponification values of 179.52 and 255.25 mgKOH/g, respectively, and as such possess advantageous properties for industrial application. When compared to one another, HRSO appears to be a more effective choice as a lubricant base. This is because of its higher viscosity index of 380.65. The outcomes of this study indicate that hydroxylated and epoxidized RSO with high oxirane content can be synthesized concurrently by one-pot multistep reactions.

Renewable energy plays a very important role in the improvement and promotion of environmental sustainability in agricultural-related activities. This paper evaluates the techno-economic and environmental benefits of deploying photovoltaic (PV)- battery systems in a livestock farmhouse. For the energy requirements of the farm to be determined, a walkthrough energy audit is conducted on the farmhouse. The farm selected for this study is located in southern Nigeria. The National Renewable Energy Laboratory’s Hybrid Optimization Modeling for Electric Renewable (HOMER) software was adapted for the purpose of the techno-economic analysis. It is found that a standalone PV/battery-powered system in farmhouse applications has higher economic viability when compared to its diesel-powered counterparts in terms of total net present cost (TNPC). A saving of 48% is achievable over the TNPC and Cost of Energy with zero emissions. The results obtained show the numerous benefits of replacing diesel generators with renewable energy sources such as PV-battery systems in farming applications.

The wide energy supply/demand gap has led the developing economies to the operation of the captive generators. This has contributed in no small way to the carbon footprint in the developing nations. Thus, the energy management initiative could assist in reducing the menace of greenhouse gas emission. Hence, the energy policy makers and planners have unanimously proposed adoption of demand side management (DSM) technique. Thus the adoption of energy efficiency technique (EET)-a DSM measures and hybrid energy system would be essential for rural electrification. This work investigates the effect of applying energy efficiency measures in rural electrification. A case study of an un-electrified rural settlement in Ibadan, Nigeria was considered. The utilization of EET techniques reduces the emission of CO2 by 62%, while technical analysis shows the feasibility of a 100% renewable fraction electricity production. Principally, application of energy efficient techniques proved to be economically and environmentally friendly. Keywords: Energy efficiency measures; emission reduction; hybrid energy system; net present cost; renewable energyJEL Classifications: Q4, P28

The use of ozone, chloramine and chlorine dioxide for water treatment results in the formation N-nitrosamines in the treated water. These groups of chemicals and other nitrogen-containing compounds have been described as disinfection by-products (DBPs) which are known for their toxicity. Nitrosamines are a potential source of nitric oxide (NO) which can bind with metals present in the sample matrix leading to formation of metal – nitrosyl complexes and dissolved metals have the potential to increase the total nitrosamines in water. This phenomenon has not received the desired attention and determination of metal-nitrosyl complexes lack standard analytical technique. Chromatography linked to various detectors is the commonest of the techniques for nitrosamine analysis but it is beset with reduced sensitivity as a result of inappropriate choice of the column. Incidentally, chromatographic techniques have not been really adapted for the analysis of metal-nitrosyl complexes. Therefore, there is need for the survey of existing techniques vis-à-vis metal-nitrosamine analysis and to suggest possible areas for method optimization., Analytical chemistry; Electrochemistry; Metals; Nitric oxide; n-nitrosodimethylamine; column; carcinogenic; chromatography

There are over 50,000 telecommunication base transceiver stations (BTS) operating on conventional diesel generators across Nigeria, giving rise to a high operational cost and emission of Greenhouse gases which can be minimized by the adoption of greener energy generation. Presented in this study, is an analysis of the techno-economic and emission impact of a stand-alone hybrid energy system designed for base transceiver stations (BTS) in the Nigerian telecom industry. Using various performance criteria the feasibility of adopting hybrid photovoltaic-diesel generator and battery (PV/DG/Battery) system is analyzed under two different diesel pump price regimes. In all, it is observed that all BTS locations across the six geopolitical zones could adopt PV/battery/DG hybrid renewable energy system in place of the diesel generator (DG) which is, presently, the main technology being used across the BTSs. Besides its economic advantages over the diesel generator, HRES configurations also performed better with respect to diesel consumption and carbon dioxide (CO2) emission.

This study aims to apply a two-stage solvent extraction and adsorption principles for base oil recovery from used lubricating oils (UBO). Methyl-ethyl ketone was utilized as the solvent for extraction and activated carbon (AC) from unripe plantain peels as the adsorbent. The activities of the solvent to oil proportions from 1:1 to 5:1 on lube oil recovery were analyzed in terms viscosity of the oil, total base number (TBN) of lubricating oil, and percent weight of metallic contents removal from used oil. The results confirm that solvent to oil ratio of 3:1 gave excellent efficiencies relating the UBO to a treated base oil (TBO) with the highest removal of contaminants, increased viscosity, high TBN after the two-stage treatments. The results after solvent extraction at varying temperatures of 30, 45, 60 °C showed the TBN increased to 32% (10.21 mgKOH/g from an initial UBO value of 6.90 mgKOH/g) at 60 °C extraction temperature. After the adsorption stage, the removal of metallic contaminants at the 60 °C extractive temperature and AC 15 wt% loading was 91% for calcium and over 91% for zinc. The optimum solvent to oil ratio of 3:1 at 60 °C yielded a base oil with a kinematic viscosity of 90.23 centiStokes, a flashpoint of 203 °C, the density of 0.909 g/ml and sulphur content of 0.64 wt%. This refined base oil obtained had close similarities with fresh Ram SN500 base oil.

Electric power is the bedrock of sustainable development in modern society. The demand for its adequate and reliable supply at a very competitive price is continuously increasing with population increase and the industrial revolution. A significant limitation to meeting this demand, is the inefficient operation of several of the existing power plants, resulting in their inability to generate electricity equivalent to their installed capacity. In this study, the exergy based performance evaluation of a major power plant in Nigeria was conducted to identify opportunities for thermodynamic improvement. Historical data of the plant was fed into HYSYS 8.8 to simulate its operations and obtain necessary thermodynamic data for assessing its performance. With the aid of codes embedded in HYSYS and the use of Ms Excel, the synthesized plant’s thermodynamics data was used for its performance evaluation. Components-wise evaluation revealed that apart from the turbines, exergy efficiencies were lower than energy efficiencies. The overall energy efficiency of the plant was found to be 33.19% while the corresponding exergy efficiency was 31.94%. The boiler was identified as the unit with the highest irreversibility and most significant contributor to overall plant’s inefficiency. It is posited that adequate knowledge of the effect of changes in operating parameters and load variation on performances will be handy in addressing inefficiencies in the boiler and other components of the plant.

Literature search has revealed that most post-combustion CO2 capture processes available to power plants are hinged on sorption technologies (chemical absorption and desorption) which are cost and energy-intensive. The colossal cost of solvents used for the absorption of CO2, the high energy requirements for the absorption & solvent recovery processes, plant design & control related complications, and environmental concerns about the solvents are some of the challenges associated with this option of post-combustion CO2 capture approach which is widely being adopted to mitigate CO2 emissions from power plants. In this study, the capture of CO2 from flue gas by exploring the concept of change of state of matter, which is essentially a physical approach to CO2capture, is presented as an alternative to the typical methods in the industry.

The research work investigated the production of adhesive from cassava starch. Cassava tubers were processed into starch-based adhesives, using two different gelatinization enhancers (that is HCl and NaOH) which were introduced separately. The adhesives were produced by considering two varied process parameters, namely percentage weight of borax in starch solution (8 – 20%) and reaction temperature (65 – 85°C). Comparative analysis of the adhesive obtained (using HCl and NaOH as gelatinization enhancers) include the determination of its bond strength, viscosity, drying time, pH and density. As the borax weight percent increases up to 14 % and reaction temperature reduces (using NaOH) the drying time increases, while the drying time reduces as both the borax weight percent and temperature reduce (using HCl). The results of the adhesive physical properties fall within the standard range for each of the properties and this implied that the adhesive produced was of high quality.

Mathematical modelling of in situ (on site) bioremediation of crude petroleum polluted soil was investigated. An unsteady state mathematical model based on bulk flow of oil through the soil and molecular diffusion through the pores of the soil was developed. The parabolic partial differential equation developed was resolved into a system of ordinary differential equations (ODEs) by orthogonal collocation method and the necessary boundary condition was used. The resultant system of ODE was solved using fourth-order Runge-Kutta method. The simulated data gave a good agreement with experimental data.

The purpose of this review is to establish and classify the diverse ways in which evolutionary computation (EC) techniques have been employed in water demand modelling and to identify important research challenges and future directions. This review also investigates the potentials of conventional EC techniques in influencing water demand management policies beyond an advisory role while recommending strategies for their use by policy-makers with the sustainable development goals (SDGs) in perspective. This review ultimately proposes a novel integrated water demand and management modelling framework (IWDMMF) that enables water policy-makers to assess the wider impact of water demand management decisions through the principles of egalitarianism, utilitarianism, libertarianism and sufficientarianism. This is necessary to ensure that water policy decisions incorporate equity and justice., Environmental science; Applied computing; Computing methodology; Civil engineering; Process modeling; Hydrology; evolutionary computation; water justice; water demand; Artificial intelligence; water equity; Sustainable development goals

Investigation on the use of KOH and NaOH catalysts for waste groundnut oil (WGO) biodiesel production, as well as the comparative adoption of response surface methodology (RSM) and artificial neural network (ANN) for the modelling of yield and process parameters was carried out in this research work. Box–Benkhen experimental design was adopted and the four process parameters considered were methanol-oil mole ratio (6–12), catalyst concentration (0.7–1.7 wt%), reaction temperature (48–62 °C) and reaction time (50–90 min). The results of this research work reveal that KOH catalyst produced higher yield of biodiesel, compared to the yield obtained from NaOH catalysed process. ANN model had 0.9241 regression coefficients (R) and 0.8539 correlation coefficients (R2) while the R and R2 calculated from RSM were 0.9290 and 0.8516 for KOH catalysed transesterification process. Also, the overall regression coefficients R and correlation coefficient R2 in the ANN model were 0.9629 and 0.9272, while the R and the correlation coefficient R2 calculated from RSM were 0.9210 and 0.8791, for NaOH catalysed WGO biodiesel production. Hence, the results typify the robustness and superiority of ANN over RSM in predicting and solving complex problems specifically in the transesterification of biodiesel, due to the larger values of R and R2 as recorded.

This work identifies the chemical components of Azadirachta indica (neem plant) leave extracts . A. indica is a vascular plant which belongs to the Meliaceae family and its use as herb in folk medicine is widely acclaimed. Essential oils were extracted from leaves of A. indica. Steam and solvent extraction methods were used with two sol- vents: Ethanol and Hexane. The crude oil extracted using both extraction methods were analyzed using GC–MS. The result of the analyses show that the major con- stituents were Eicosane (9.7662%), Diacenaphtho[1,2-j:1 � ,2 � -l]fluoranthene (11.301%), Phenol, 4-[[(4-methoxyphenyl)methylene]amino]- (11.84%) and (3Ar,6S,9ar)-1,2,3,4,5,6,7,9a- octahydro-8-methyl-3a,6-methano-3ah-cyclopentacycloocten-10-one (36.883%) in steam extracted oil; Eicosane (10.259%), Diacenaphtho[1,2-j:1 � ,2 � -l]fluoranthene (13.51%) and Butanamide, N-(2-methoxyphenyl)-3-oxo- (16.615%) in the ethanol extracted oil, and (3Ar,6S,9ar)-1,2,3,4,5,6,7,9a-octahydro-8-methyl-3a,6-methano-3ah-cyclopentacycloocten- 10-one (10.72%), n-Hexadecanoic acid (14.688%) and 9,12,15-Octadecatrienoic acid, (Z,Z,Z)- (34.719%) in the hexane extracted A. indica essential oil.

Efficient pre-treatment has been found to be crucial step before enzymatic hydrolysis of cellulose into fuels or chemicals. As a result various pretreatment methods have been developed to facilitate these bio-conversion processes, and this research focuses on the effect of two pretreatment methods such as liquid hot water and sulphuric acid pre-treatment to remove some of the components like lignin and hemicellulose which form structural barrier to enzymatic accessibility of cellulose in corn cobs and sawdust. The cellulosic materials were first dried in oven at 65 o C for 24 hours, and using solid to liquid ratio of 1:10, the two methods were carried out at resident times ranging from 10 - 40 minutes. The liquid hot water method involved heating the cellulosic materials in water at 120 o C and 1atmosphere in a pressure vessel, and for the second method, the dried cellulosic materials were refluxed in 5 % sulphuric acid at a temperature of 120 o C. Pretreated samples were filtered and liquid fractions were analyzed for the presence of reducing sugars, while solid residues were dried in the oven and weighed to measure the mass lost during pretreatment as a pointer to lignin breakdown. It was observed that the mass lost increased with time for both pretreatment methods, but the liquid hot water pretreatment gave higher lignin and hemicellulose removal when compared to the sulphuric acid pre-treatment. The pretreated materials were hydrolyzed with two combinations of commercial enzymes namely cellulase/ hemicellulase and cellulase/β glucosidase. The reducing sugar was measured using Dinitrosalycilic acid (DNSA) method and the sugar yields from corn cobs were higher than that of sawdust when subjected to similar process conditions, and the enzyme combination of cellulase/glucosidase gave higher yields of reducing sugars. A model equation which describes the hydrolysis process was developed from first principles and the experimental data obtained gave a good fit.

This study investigates the appropriateness of exergy calculation using Aspen Plus Process Simulator which has a robust data library and powerful engineering calculation capabilities. The simulator was used for the thermodynamic performance of a raw mill (RM) and raw materials preparation unit in a cement plant in Nigeria using actual operating data. The raw mill has a capacity of 240,000 kilogram-material per hour. Also, both exergy and exergetic efficiency of raw mills from three literature sources were investigated and compared with the simulation results from Aspen Plus process model. The results were subjected to statistical analysis using ANOVA. The exergy efficiency for the raw mill studied using Aspen plus simulator modelling technique was found to be 21.4%. It was found that the difference in exergy efficiencies of the simulation results of the three-literature data vary within ±2.5% of the published results. The present method using the Aspen plus simulator is suggested as a useful tool in making informed decisions for developing energy policies and exergy utilization, providing energy conservation measures in improving the efficiency of the system.