Potential Use of Industrial Cocoa Waste in Biofuel Production

Worldwide, the wastes derived from food production are generated in elevated volumes annually. In particular, the cocoa industrial wastes represent a source of usable biomass for the elaboration of new products such as food, livestock feed, cosmetics, and chemical products, and they can even be used for the generation of biofuels. The cocoa industrial wastes include cocoa pod husk, mucilage, and bean shells, which contain compounds of interest for different industries. However, the lignocellulose content of these by-products requires a pretreatment to fully utilize them; thus, different biofuels can be produced, depending on the conversion technology used to obtain the highest biomass yield. Recent studies reported the use of cocoa industrial wastes for the production of solid, liquid, and gaseous biofuels; nevertheless, the most common use reported is as a direct combustion source, which is used to supply the same production plants. Therefore, the objective of this work is to carry out a review on the uses of the by-products generated from cocoa for the generation of biofuels, as well as the technological concept applied for the transformation. In addition, the future trends indicate the relevance of using catalysts in production to increase reactions in the conversion of compounds, including the use of statistical models to optimize the processing variables.

Development of the Method for Predicting and Calculating the Operation of Sorption Systems for Cleaning the Generator Gas based on Dolomite Use. Part II

At present, instead of a direct combustion of solid fuel, its thermochemical conversion is exten-sively used to produce a generator gas. The use of this technology is connected with the need for gas purification. One of the promising and widely spread sorbents for the purification of the generator gas is dolomite, whose particles compose the active component of the bed filters. Forecasting the technological characteristics of the functioning of the bed filters of a various de-sign is an extremely urgent task. The objective of the study is to develop a method for forecast-ing and calculating the operation of sorption systems for purification of the generator gas based on dolomite. It is achieved by constructing and verifying a mathematical model of the function-ing of the bed sorption filter with a radial-axial flow pattern of the generator gas through the do-lomite filling. The Markov chains theory of a mathematical apparatus is used to design the one-dimensional mathematical model of the process with discrete space and time. The main recurrent balance ratio is formed at each calculation step taking into account the current characteristics of the process, which makes the model nonlinear. The significance of the research is that an approach to the problem of increasing the reliability of the description and reliability of forecasting technological processes in a bed filter was proposed based on the construction of mathematical models of these processes, in which the filter is considered as a system with distributed characteristics, and the calculation was based on local exchange potentials between particles and gas.

A Study on the Submarine Air Independent Propulsion System: Focused on Submarines Currently in Operation

Submarines are weapons systems that have been proven to be useful in battle since World War I and have continued to improve the efficiency of propulsion systems in order to be used efficiently on the battlefield. In particular, countries that unable to utilize nuclear propulsion systems make efforts to increase the efficiency of Air Independent Propulsion systems, and typical examples are fuel cells, Stirling engines and MESMA. It is also expected that the development of new propulsion systems such as hydrogen-reformer fuel cells, metal-air fuel cell and direct combustion propulsion systems will continue, so the characteristics of these will be examined and the performance based on the published data be checked in this thesis.

Development of the Method for Forecasting and Calculating the Operation of Sorption Systems for Purifying the Generator Gas Based on Dolomite Use. Part I

A trend towards energy diversification creates the expansion of small energy facilities that involve the production of solid fuel generator gas, rather than its direct combustion. The economic indicators of such facilities significantly depend on the efficiency of the generator gas purification. A promising sorbent for the purification of the generator gas is dolomite. When working as a sorbent, dolomite particles usually form a layer, through which the generator gas that is heating them is filtered. The objective of the study is to determine kinetic parameters of the thermal decomposition of dolomite, depending on the size of the sample. It was achieved using the thermogravimetric study of the thermal decomposition of single dolomite particles under static conditions at various temperatures. The most significant scientific result was that a dependence of the kinetic parameters of the gross reaction on the size of the initial particle is revealed, and a regression equation was proposed for its quantitative assessment. In addition, since the heat treatment process of the material was fairly long lasting, and the sizes of the particles allowed them to be referred to thermally thin bodies, it was inferred that the effect of a grain size on the reaction kinetics should be explained through the description of the evacuation process of gaseous reaction products from the material. The significance of the results of the study lies in the fact that a particle size must be considered as a factor that affects the progress of the technological process, which increases the reliability of the calculation of sorption-catalytic systems based on the use of dolomite.

Energy Properties and Biomass Yield of Miscanthus x Giganteus Fertilized by Municipal Sewage Sludge

The application of municipal sewage sludge as fertilizer in the production of non-food energy crops is an environmentally and economically sustainable approach to sewage sludge management. In addition, the application of municipal sewage sludge to energy crops such as Miscanthus x giganteus is an alternative form of recycling nutrients and organic material from waste. Municipal sewage sludge is a potential source of heavy metals in the soil, some of which can be removed by growing energy crops that are also remediation agents. Therefore, the objective of the research was to investigate the effect of municipal sewage sludge applied at three different rates of 1.66, 3.22 and 6.44 t/ha on the production of Miscanthus. Based on the analyses conducted on the biomass of Miscanthus fertilized with sludge from the wastewater treatment plant in three fertilization treatments, it can be concluded that the biomass of Miscanthus is a good feedstock for the process of direct combustion. Moreover, the application of the largest amount of municipal sewage sludge during cultivation had no negative effect on the properties of Miscanthus biomass. Moreover, the cellulose and hemicellulose content of Miscanthus is ideal for the production of second-generation liquid biofuels. Fertilizer treatments had no effect on the content of cellulose and lignin, while a significant statistical difference was found for hemicellulose.

Potential of Pine Needle Biomass as an Alternative Fuel to Mitigate Forest Fire in Uttarakhand Himalayas - A Review

Pine needle is a typical biomass which is abundantly available in Uttarakhand hills. This shredded biomass contributes significantly in forest fire occurring regularly in Uttarakhand. Different energy harnessing routes as direct combustion, anaerobic digestion, pyrolysis, gasification, and briquetting for pine needle were reviewed. These routes were further compared on the basis of energy consumption and energy efficiency of the processes as per the available literature. The review suggested that briquetting of pine needle and its anaerobic digestion are two most energy efficient methods having energy efficiency of 88% and 41.6%, respectively. The estimated energy required for briquetting of 1 ton pine needle was 1370.5 MJ, whereas for gasification it was 1170 MJ

Effect of Incorporation of Rice Husk Ash Instead of Cement on the Performance of Steel Fibers Reinforced Concrete

The production of rice is significant worldwide; the husk produced is generally used as a combustible material for the preparation of paddies, delivering energy through direct combustion as well as by gasifying. Annually, 7.4 million tons of Rice Husk Ash (RHA) is produced and poses an incredible danger to the environment, harming the land and the encompassing zone where it is unloaded. In the transformation of rice husk to ash, the ignition cycle eliminates the natural products, leaving silica-rich remains. These silica-rich remains have proven to have potential to be utilized in concrete as a limited substitution of cement to enhance the concrete compressive strength. Steel fibers’ incorporation increases the concrete tensile strength, balances out concrete samples, and changes their brittle behavior to a more ductile response. In the current study, the influence of various doses of Rice Husk Ash (RHA) used in concrete in the presence and absence of steel fibers and concrete performance has been examined. A total of nine mixes have been designed: one was a control, four were without steel fibers containing only RHA, and the last four mixed RHA with steel fibers from 0.5 to 2%. Tests with 5, 10, 15, and 20% percentages of RHA replacing the concrete have been targeted. Results have been compared with the reference samples and the reasonability of adding Rice Husk Ash to concrete has been studied. From the results, it was noted that about 10% of cement might be replaced with Rice Husk Ash mixed in with steel fibers with almost equal compressive strength. Replacing more than 15% of cement with RHA will produce concrete with a low performance in terms of strength and durability.