Mathematical optimization of a supply chain for the production of fuel pellets from residual biomass

One of the main concerns of humankind in the last years is the availability of energy sources. Research has been focused on finding clean and renewable ways to satisfy the energy demand worldwide. In the particular case of the state of Guanajuato, Mexico, clay industry burns each year about 15,000 m³ of fuel oil and residual oils, and 96,000 t of wood derivatives. As a way to reduce the environmental impact of clay industry, the use of solid fuel pellets, obtained from vegetable residual material, is proposed. The raw material for the pellets is obtained from agribusiness and from the cities of the state. The solid biofuel has high density, low content of humidity, a homogeneous shape and high energy density. Nevertheless, special care must be taken about the location of the production facility and hubs, in order to make the production of the biofuel economically feasible. Furthermore, to have an environmentally friendly fuel, the supply chain and the production process must minimize the global environmental impact. In this work, a mathematical programming model is proposed to determinate the optimal location of the production facilities, the hubs, and the best distribution logistics. The problem is modelled using a general disjunctive programming approach, and then relaxed into a mixed-integer non-linear programming (MINLP) problem. It has been determined that the main plant should be located in the city of Irapuato, while secondary plants must be established in the cities of León, Irapuato, Abasolo and Salamanca. Moreover, it has been estimated that, when the residual biomass is converted into pellets, about 72,548 t/year of equivalent CO₂ are avoided in the main plant, together with 24,182 of equivalent CO₂ avoided per secondary facility.     

Analysis of bioenergy production at different levels of integration in energy-driven biorefineries

In this paper, a techno-economic and environmental assessment is performed to compare the stand-alone process and biorefinery ways to produce biodiesel, ethanol and butanol as potential cases for bioenergy production using fresh fruit bunches as raw material. Different levels of integration are considered (e.g., mass and energy integration, non-conventional technologies) along with the analysis of the process scale to determine the economic profitability and environmental impacts of the proposed cases. The results demonstrated that the biodiesel production based on the biorefinery concept has a positive effect on the profitability of the stand-alone process at different scales. The economic results were compared with data reported in the literature. Furthermore, the life cycle analysis of the proposed cases suggested that the deployment of the biorefinery concept at different levels of integration in the oil palm supply chain reduced the environmental impact of the biodiesel production, which was selected as the hotspot of the evaluated cases.     

Eco-efficiency in the transformation of forest biomass residues in electrical energy

Clean Technologies and Environmental Policy - The use of forest biomass residues to generate electricity can contribute to the sustainability of the energy matrix, circularity in forest production...     

Carbon and nitrogen trade-offs in biomass energy production

This contribution provides an overview of carbon (CFs) and nitrogen footprints (NFs) concerning their measures and impacts on the ecosystem and human health. The adversarial relationship between them is illustrated by the three biomass energy production applications, which substitute fossil energy production applications: (i) domestic wood combustion where different fossil energy sources (natural gas, coal, and fuel oil) are supplemented, (ii) bioethanol production from corn grain via the dry-grind process, where petrol is supplemented, and (iii) rape methyl ester production from rape seed oil via catalytic trans-esterification, where diesel is supplemented. The life cycle assessment is applied to assess the CFs and NFs resulting from different energy production applications from ‘cradle-to-grave’ span. The results highlighted that all biomass-derived energy generations have lower CFs and higher NFs whilst, on the other hand, fossil energies have higher CFs and lower NFs.     

Residues of bioenergy production chains as soil amendments: immediate and temporal phytotoxicity

The current shift towards bioenergy production increases streams of bioenergy rest-products (RPs), which are likely to end-up as soil amendments. However, their impact on soil remains unclear. In this study we evaluated crop phytotoxicity of 15 RPs from common bioenergy chains (biogas, biodiesel, bioethanol and pyrolysis). The RPs were mixed into a sandy soil and the seedling root and shoot elongation of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), and wheat (Triticum aestivum L.) were measured. Immediate phytotoxic effects were observed with biodiesel and bioethanol RPs (root elongation reduced to 14-60% for the three crops; P<0.05). However, phytotoxicity was no longer significant after seven days. Digestates had no phytotoxic effect whereas biochars ranged from beneficial to detrimental depending on the original feedstock and temperature of pyrolysis. Biochar amendment alleviated phytotoxicity of bioethanol by-products for wheat and radish. Phytotoxicity assessment is critical for successful soil amendment with bioenergy RPs.     

广西木薯茎秆资源的能源利用

文章分析了广西木薯茎秆资源可获得性及燃料性状,进而讨论了开发木薯茎秆资源的可行性及商业价值,证明木薯茎秆是优秀的生物质原材料,具有开发固体成型燃料及热电联产的价值。     

The potential of biomass supply for energetic utilization in a small Italian region: Basilicata

The European Union Directive 2009/28/EC (European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing directives 2001/77/EC and 2003/30/EC, Directive 2009/28/EC) establishes a common framework for the use of energy from renewable sources in order to reduce both greenhouse gas emissions and reliance on fossil fuels from foreign markets; more specifically the EU has the ambitious goal of reaching a 20 % share of energy from renewable sources in the overall energy mix by 2020. These objectives could drive policies that offer substantial economic subsidies for the use of renewable energy, both in Italy and in many other European countries. For all these reasons, biomass (one of the major sources of renewable energy) plants are getting a lot of attention in Italy, but it is necessary to determine whether using of this type of energy is environmentally beneficial and economically feasible. In this study, we evaluate the energy and so the environmental aspects by considering both current and potential biomass supplies available for energy utilization in a small region in the South of Italy: Basilicata, as well as the consequences of this energy conversion at both the local and the global scale.     

Environmental impact of microalgal biomass production using wastewater resources

The current study provides a life cycle assessment (LCA) of microalgal biomass production using the effluent collected from the stabilization lagoon of a municipal sewage treatment as culture medium. Strains of two native microalgae from the stabilization lagoon (Desmodesmus sp. and Scenedesmus sp.) were grown in three different media: filtered effluent, autoclaved filtered effluent and conventional medium for cultivation of freshwater microalgae. Environmental analysis was carried out within the methodological framework of the LCA, by the life cycle impact assessment method ReCiPe 2008. A comparative analysis was performed for three endpoint categories: damage to human health, damage to ecosystem diversity and damage to resource availability. For both microalgal strains, the results confirmed that microalgal biomass production in non-autoclaved effluent has the lowest potential environmental impact. An additional analysis indicated that the potential environmental impact caused by discharge of effluents treated with microalgae is higher than the impact of untreated effluents. Despite the decrease in N and P in the effluent after microalgal treatment, the potential environmental impact of its discharge is strongly correlated with the electric consumption required for microalgal cultivation. This consumption could be lowered by decreasing the expenditure for illumination and mixing using outdoor microalgal cultivation.     

我国生物质能发展现状及对策

评述和分析了国外发展新兴能源——生物质能的形势和我国的发展现状,提出了发展我国生物质能技术的策略。分析指出:生物质能日益受到世界的广泛关注。发达国家通过立法和制定科技计划大力支持对燃料乙醇、生物柴油等生物质能的开发与利用,促进了生物质能的发展,美国在发展燃料乙醇上显示出了旺盛的势头,2006年产量达1460万吨,居世界第一;我国在沼气、气化发电等方面取得一定成绩,但燃料乙醇生产仍以陈化粮为原料,难以降低成本,生物柴油生产尚处于起步阶段。从长远看,我国必须解决原料替代问题,走非粮食原料生产燃料乙醇的路子。     

Assessment of bioenergy production from mid-rotation thinning of hardwood plantation: life cycle assessment and cost analysis

Forestry thinning logs, a low-value by-product of the forestry industry, present an opportunity for bioenergy production. It can be converted into solid, liquid, and gaseous fuels via different conversion techniques. Comparative life cycle assessment and life cycle costing (LCC) analysis were conducted to evaluate six options: woodchip gasification for power generation; wood pellets gasification in combined heat and power plant; wood pellet combustion for domestic water and space heating; pyrolysis for power generation; pyrolysis with bio-oil upgrading to transportation fuels; and ethanol production for transportation fuel mix. The functional unit used in this study was the treatment of 1 Mg of biomass. Global warming; acidification; eutrophication; fossil depletion, human toxicity; and land use impact categories were considered. The LCC also included greenhouse gas (GHG) emissions costs. The effects of uncertainties in the system on the overall performance of the scenarios were also evaluated. The results showed that all options except for ethanol production are GHG emission negative. Woodchips gasification performed best in all environmental impact categories and had the lowest LCC ($177.6/Mg). Biomass drying consumed more than 50% of the energy requirement for all options except for production of liquid transportation fuels via upgrading of pyrolytic oil, in which case the fuel upgrading process was the most energy intensive. In terms of energy return, all options, except electricity production through pyrolysis, offered positive return. The results highlight the importance of using biomass with least possible processing in order to maximise environmental and energy return and minimise LCC.     

Utilization of woody biomass combustion fly ash as a filler in the glue used for plywood production

The feasibility of the effective utilization of combustion ash from a woody biomass power plant as a novel filler added to adhesives used in plywood production is investigated. For this, plywood was prepared with glues containing combustion ashes having different properties, and the adhesion performance of the glues was examined in detail and compared with that of a glue containing calcium carbonate powder as the filler. Through optical microscopy observations and analyses of the adhesive layer in the plywood, the relationship between the properties of the glue, the structure of the adhesive layer, and the adhesion performance was unraveled. Results revealed that the glue containing woody biomass combustion ash without the unburned carbon component shows a better and more homogeneous adhesion performance than that containing calcium carbonate powder. The adhesion performance could be enhanced more uniformly by decreasing the particle size of the filler. The study also indicated that the difference in the adhesion performance according to the kind of filler is not due to the difference in the chemical structure of the adhesive layer, but because of the difference in the denseness of the adhesive layer dominated by the viscosity of the glue. Thus, this study confirms that woody biomass combustion ash could be practically utilized as a filler substitute of calcium carbonate powder in glues for manufacturing plywood.     

Exploring the circularity potential regarding the multiple use of residual material

Clean Technologies and Environmental Policy - Building on recent insights in exploring material circularity, this study attempts to develop a methodological approach toward allocating an available...     

An integrated lignocellulosic biorefinery design for nanomaterial and biochemical production using oil palm biomass

Clean Technologies and Environmental Policy - Oil palm empty fruit bunch (EFB) biomass valorisation for high-value applications has been a current focus in research due to the vast amount of...     

Study of hydrolysis and acidification process to minimize excess biomass production

In this paper, a new wastewater treatment process has been presented to minimize excess biomass production in which both excess sludge digestion and wastewater treatment are conducted simultaneously in the system. The process is modification of conventional activated sludge process with insertion of two facultative basins in the sludge return line. The excess biomass in the aeration tank is recirculated to the first facultative tank. It was observed that: (1) The amount of excess biomass is reduced to nearly aero when 5.95 g/day excess sludge is recirculated from the aeration tank to the first facultative tank at COD(Cr) loading of 2.31 kg/m(3)day. A biomass experiment of 1000 mg/L was maintained at 2.31 kg-COD(Cr)/m(3)day without drawing excess sludge for 6 months of experiment period. Inert organic substances did not seem to accumulate. The effluent quality has been well below the discharge limit. (2) On the basis of infrared spectroscopy proved that dye molecule in wastewater were firstly absorbed on the sludge, and then the bond energy of was gradually weakened and decomposed and eliminated lastly.     

Pyrolysis/gasification of biomass for synthetic fuel production using a hybrid gas-water stabilized plasma torch

An experimental plasma-chemical reactor equipped with a novel hybrid gas-water stabilized torch is available at IPP Prague for the innovative and environmentally friendly plasma treatment of waste streams with a view to their sustainable energetic and chemical valorization and to a reduction of the emission of greenhouse gases. Gasification/pyrolysis of biomass was experimentally studied using crushed wood as a model substance. The experimental results demonstrate homogeneous heating of the reactor volume and proper mixing of plasma with treated material in spite of the low plasma mass flow rate and constricted plasma jet. The conditions within the reactor ensure complete destruction of the tested substance. The economical viability, environmental performance and safety of biofuels/hydrogen produced from syngas resulting from the plasma-thermochemical gasification of a very broad range of second generation biomass feedstock will be investigated. The performance of several types of plasma torches and of possible combinations of torches will be compared. The final biofuels will be tested in the existing Internal Combustion Engine (ICE) test stands.     

Fuelwood production in developing countries: Toward an appropriate forest technology

This paper addresses the need for appropriate forest technology as a solution to the rural fuelwood shortage in developing countries. Many such solutions are proposed with little reference to existing local needs and resources. Complex wood harvesting technologies require a long time to diffuse through a population. Therefore, increases in productivity can be better achieved through focusing on the improved maintenance and deployment of proper hand tools. Evidence from Kenya is used to demonstrate the improvements that can be made in hand-tool production and maintenance. Most fuelwood users currently manage trees to produce firewood in the form of fuelwood sticks, not large logs. Appropriate fuelwood production systems should be developed, based on the principles of coppicing and pollarding, short rotation periods, and producing small diameter fuelwood sticks. A hypothetical fuelstick project is discussed to show that not only are such systems possible, but they can be economically superior to conventional solutions.     

Optimization of growth determinants of a potent cellulolytic bacterium isolated from lignocellulosic biomass for enhancing biogas production

Clean Technologies and Environmental Policy - Anaerobic digestion of lignocellulosic biomass is limited by inefficient hydrolysis of recalcitrant substrates, leading to low biogas yields where...     

The potential application of red mud in the production of castings

The bauxite industry in Jamaica is the third largest producer of alumina in the world. Because of the technological method of processing the bauxite, there is a large amount of the world's red mud residue being disposed in Jamaica. The magnitude of the industry's production of alumina and the red mud disposal problem as a by-product is of the same order.

This research was conducted to investigate the feasibility of using a mixture of red mud and the traditional silica sand to produce quality-casting component.

The porosity of the aluminium specimens obtained from the red mud castings showed that porosity increased up to two-fold, depending on the ratio of sand and red mud. For applications where optimum casting strength is important, the use of 100% red mud may be unsatisfactory.

Although there are other variables that affect the quality of the mixture of silica sand and red mud mould in castings, the result is very significant given the possibility of applying portions of red mud in other casting techniques.