Modeling and Optimization of Biomass Supply Chain for Energy, Chemicals and Materials Productions

In the growing concerns towards global environmental qualities and sustainable feedstocks supplies, scientific and technological efforts were intensified to utilize alternative renewable resources. In this regard, biomass appeared to be one of the potential feedstocks because it is generally carbon neutral and essentially renewable. Furthermore, biomass is virtually found in every part of the world in abundance and could provide socio-economic benefits. However, if it is not managed properly, biomass will be less competitive due to several issues that are associated with its supply chain. Typical biomass supply chain has a series of activities such as growing, harvesting, transporting, aggregating, and conversion which systematic and efficient flows of materials from the fields to the users are highly important. Biomass has competing uses, different kinds and origins which are potentially exploitable, poor geographic distributions for retrieving and transporting, and variations in physical and chemical properties. It is difficult to make informed decision for any biomass utilization project without having an optimal supply chain. This research intended to solve those issues by modeling and optimizing biomass supply chains for manufacturing energy, chemicals, and materials based on their respective processing routes. The aim was not only to focus on energy production from biomass but also to include chemicals and materials because of several factors such as an emerging cost competitive energy resource such as shale gas, highly volatile energy prices, and customer’s preparedness and acceptances. Furthermore, it also could leverage biomass plantations on the producers’ sides. The biomass supply chain model has considered annual profitability of producing products as the performance indicator. It was derived from revenues of selling the products subtracted all the associated costs such as biomass cost, transportation cost, production cost, and emission treatment costs from transportation and production activities. It summed up simultaneously all the profitable processing options that have existed in the superstructure to yield the optimal value, while a single ownership was assumed for the whole supply chain’s facilities. Three optimization models have been developed and implemented in GAMS (General Algebraic Modeling System). The first one was the supply chain’s optimization for Omtec Inc., located in Southwestern Ontario. It was a research collaboration between Omtec and the Department of Chemical Engineering, University of Waterloo, under the Natural Sciences and Engineering Research Council of Canada’s Engage funding. Currently, this company produces bio-filler and briquette from wheat straw. They were planning for business expansion and to diversify the existing products’ portfolios for future investment. It involved utilizations of biomass sources other than wheat straw and productions of products other than bio-filler and briquette. A superstructure that has assisted in the model’s formulation provided alternatives in the biomass processing routes which in turn aimed for profit maximization. Optimal results indicated that an annual profit of $22,618,673 was expected to be achieved, and this value was contributed mainly by the sales of bio-filler, bio-ethanol and by-products from the milling plant. The developed model has offered flexibilities in biomass resources utilization and technological uses for Omtec Inc. Since the model only considered biomass cost, transportation cost and production cost, it did not evaluate environmental performance in the supply chain. The second optimization model was for the supply chain of Malaysian palm oil empty fruit bunches for multi-products productions. As one of the main palm oil producer in the world, Malaysia within its biomass initiatives and strategic plans has promoted the local biomass source utilizations for value-added products. The developed model has considered environmental performance in the supply chain by introducing emissions from transportation and production activities as one of decision variables. The superstructure showed processing alternatives for converting the biomass source into intermediates and products, transportation networks between processing facilities, and options for product’s direct sale or for further refinements. Particularly, option for directly selling the produced product versus further refinement was relevant due to the economic uncertainties. With the available parameters, the optimal profit was found to be$ 713,642,269 per year. This economic bonanza was seemed ideal and have lack of optimal selections for processing routes and transportation modes. The third and the last model has extended the second model by incorporating integer variables for important decisions related to the best processing routes and transportation modes in the supply chain. With numerous alternatives available, selecting best processing route for producing a product was imperative because of several factors associated with that such as product’s competitiveness, viability and status of technology, environmental impacts, and so on. The optimal decisions about transportation amounts and modes have directly influenced the overall economic profitability as well as biomass accessibility and mobility. At a planning stage, questions might arise whether to use truck, train, barge or pipeline for transporting biomass and derived products from processing facilities to the desired destinations in the most economical way. With that in mind, the model has considered all of these dilemmas and provided useful information. The previous superstructure has been modified to include states of produced products whether they were solid, liquid or gases. Assignments for the transportation modes were done according to this modification. With the given parameters and constraints, the optimal annual profit was $1,561,106,613 per year. Since majority of utilization projects involving biomass are still under research and development stages and there are difficulties to consolidate real data, approximations of models’ parameters could not be avoided. The obtained optimal values were subjected to the qualities and availabilities of these approximated parameters. However, sensitivity analysis were performed by varying selected parameters and the effects to the objective functions were recorded. All in all, it was a strong hope that this research could solve typical issues related to the biomass supply chain and would integrate well with the efforts to simulate the biomass utilization process individually

Analysis of Optimal Power Reduction Schemes for An LNG Plant

In this work, a typical Mixed Refrigerant Cycle (MRC) for the production of liquefied natural gas (LNG) has been selected for the analysis of potential power reduction schemes. However, such analysis requires complete process data for the MRC liquefaction process flowsheet. Unknown data were be subjected to rigorous simulation and reconciliation. Data reconciliation approaches for the MRC flowsheet involved the combination of structural decomposition of complex units and systematic estimations of unknown variables. Simulations performed and the data obtained is validated against published data. The errors in the data were reconciled by minimizing the sum of squared error (SSE) between the simulated data and the published data. After five iterations, the reconciliation trial with the smallest SSE of 0.002% was selected and considered as the base case MRC process flowsheet. The base case flowsheet was then analyzed to establish its thermodynamic performances using WORK software. The software also optimized the mixed refrigerant compositions. Three power reductions schemes have been proposed that include the process expander, the multistage compressions with intercoolers, and the multistage compressions with intercoolers incorporating the process expander. Each of the proposed schemes was compared, utilizing both the current and the optimized mixed refrigerant compositions. As a result, six power reduction options were generated. Each of the six options was then simulated on HYSYS

A model-based approach for biomass-to-bioproducts supply chain network planning optimization

Supply chain network operation for biomass conversion and utilization is one of the major areas with influence on biomass-related technological progress and commercialization activities. This paper contributes towards optimizing a biomass-to-bioproducts supply chain planning operation by considering multiple cost factors including biomass resource acquisition cost, production cost, and transportation cost as well as direct sales to meet market demands. A superstructure-based modeling approach provides alternatives of biomass processing routes towards an objective of maximizing annualized profit. The formulated model entails five echelons and is implemented on a practical supply chain operational planning case study that involves a biomass-based manufacturing company in southwestern Ontario, Canada intent on long-term business expansion and product portfolio improvement. The results obtained indicates that an optimal product mix comprising a number of products from different processing stages (including preprocessing) can be expected to be achieved, with profit mainly derived through the sales of biofiller, bioethanol, and byproducts. Importantly, the developed model demonstrates the applicability of such a model-based approach in offering insights on operational optimization to attain economic decision-making on biomass resource utilization and processing route selection

A review of pyrolysis of oil palm empty fruit bunches (EFB) to produce bio-energy productions

Pyrolysis is a thermochemical conversion technology of biomass feedstock to produce bio-energy and chemicals in the absence of oxygen. Biomass pyrolysis can be classified into three main categories, which are slow, fast and flash pyrolysis, depending on heating rate and residence time. The bio-products of this process consist of bio-char, biooil and bio-syngas. The yield of these products is affected by operating conditions of the process, such as temperature, heating rate, reaction time, pressure, gas flow rate, feed rate, particle size and feedstock composition. Oil palm empty fruit bunches (EFB) were studied in this review as a biomass feedstock of the pyrolysis process, because it is abundance in Malaysia. Malaysia is considered the second largest producer of palm oil in the world. EFB has been used as a potential alternative of bio-energy sources to reduce negative environmental impact of global warming, due to its environment-friendly nature. This study reviews the summary of new studies on pyrolysis process of EFB to produce bio-energy and chemicals. The paper also presents the detail of a composition of EFB, the process design and classification, operating condition that affects the process, the reactors, and various products and its applications

Optimal biomass transportation model

The transportation represents a key proportion of the operational cost for the biomass industries worldwide. As biomasses are mainly carried by trucks for parts of the transportation, the focus of this paper is on the transport of treated and untreated biomass (rice husk, empty fruit bunch, and woody biomass) by large, medium and small trucks. The objectives were to formulate biomass transportation model for transporting treated and untreated biomass resources and to obtain optimal result for selecting the best transportation mode. By screening of biomass types, locations for treated and untreated biomass resources and screening of suitable transportation mode used, the important model parameters were obtained and linear programming for minimizing overall transportation costs was formulated. General Algebraic Modelling System (GAMS) software was used to solve the optimization formulations. From the optimization result obtained by using GAMS, large truck was selected to be the best transportation mode for treated, untreated and hybrid biomass since it showed minimal overall transportation cost

Process systems engineering for sustainable photographic lens production: a review

Photographic lens is an invention to duplicate human eye functions and operations. Starting with seeing and focusing the object, the lens then transmits lights containing information of the scene such as colours, brightness and shapes to the digital sensor or photographic film. To produce such invention, it comprises complex steps which include material selection and processing, lens machining and finishing. Being the first of its kind, this paper will review the roles of process systems engineering (PSE) in the manufacturing of sustainable photographic lens from R&D and commercial angles. The review will detail PSE contributions for each of the step and highlights the related challenges in implementation

Importance of microalgae and municipal waste in bioenergy products hierarchy—integration of biorefineries for microalgae and municipal waste processing : A review

In the context of global advancements, the imperative of a sustainable energy supply looms large. Biomass, an adaptable and renewable resource, has garnered attention for its potential contributions, although economic uncertainties persist due to the intricate web of processing pathways. In response, the biorefinery concept emerges as a structured strategy to optimize the processing of microalgae and municipal solid waste (MSW), capitalizing on their multifaceted potential to yield diverse end-products. This review underscores the critical significance of a cohesive biorefinery paradigm that unites the processing of microalgae and MSW, unveiling their capacity to generate a spectrum of high-value products. The utilization of mixed-integer linear programming paves the way for an optimal biorefinery model that navigates through complex decisions. Challenges encompass the array of diverse feedstocks and the preliminary nature of data availability. The overarching goal of this research is to discern optimal pathways for the conversion of MSW and microalgae into energy and valuable products, with a focus on enhancing waste utilization and augmenting the energy supply. In the broader landscape, this comprehensive review advances strategies for sustainable energy generation and waste management, invigorating innovative approaches to shape future progress. By illuminating pathways towards maximizing the potential of biomass resources, this review contributes to the ongoing discourse on sustainable energy and waste utilization

Modelling and optimization of biomass-based cogeneration plant

High energy demand and energy availability lead to the increasing of unpleasant energy situation. It is exacerbated if fossil fuels are the only energy source as it contributes to climate change and global warming. Thus, governments are focusing on the usage of natural resources as fossil fuel substitution. This study focused on the modelling and optimization of biomass-based cogeneration plant. The objective was to model, simulate and optimize the cogeneration plant which used torrefied EFB pellet as fuel in Aspen Plus simulator. Firstly, suitable biomass resources in Malaysia was identified. Next, a typical process flow diagram of cogeneration from the published literature was referred. Then, parametric and structural optimization were conducted. From the simulation, 1.764 MW of power was generated and it was observed that pellet flow rate, water flow rate, air flow rate and boiler temperature influenced the power generated. Five options with different structural designs were formulated in GAMS. It was found that the plant should focused on producing power and medium pressure steam to optimize the profit. The findings concluded that biomass-based cogeneration plant was technically feasible to be deployed. However, further refinements in the optimization aspect should be developed to obtain a more accurate optimal results

Aspen Plus simulation of optimal biogas production in anaerobic digestion process

The demanding uses of fossil fuels and their associated environmental footprints are driving researches into renewable energy productions from organic resources and waste. Anaerobic digestion (AD) is an environment-friendly and cost-effective method to produce biogas from biomass. This biogas can be used in power generation, heating systems and in a combined heat and power (CHP) system. Nevertheless, biogas produced from AD contains a big fraction of CO2 and less methane purity. Aspen Plus simulation model was developed for the AD process to produce biogas, highlighting the economical potentials and environmental benefits. Four steps of AD including hydrolysis, acidogenesis, acetogenesis, and methanogenesis with eight reactions were simulated based on the respective stoichiometries. Optimization has involved the search to identify optimum feed flow rate and operating pressure to produce the maximum amount of pure methane. The obtained results showed that optimum feed rate was 0.36 l/day and operating pressure of 3 bar with hydrogen flow of 180 l/day. By using these optimum conditions, maximum amount of methane with high purity was achieved. Otherwise, through biomass natural decomposition, the methane would escape to the atmosphere as one of those significant greenhouse gases

Modelling and optimization of torrefied pellet fuel production

Torrefaction is a thermal process to convert biomass into a coal-like material, which has better fuel characteristics than the original biomass. Torrefied biomass has more energy density and hydrophobic which is superior quality for handling and storage. The objective of this research was to develop a simulation model of the torrefied pelletization process from empty fruit bunch (EFB). The process was simulated using ASPEN Plus. Optimization involved a selection of the model option that produced the maximum mass yield and minimum energy requirement, with a converged base case simulation as a starting point. Torrefied biomass pellet offered coal-like properties such as high heating value, brittle, high bulk energy density and more hydrophobic. These properties could potentially avoid costly power plant modifications. On the other hand, Malaysia has issued National Biomass Strategy 2020 with target to solve the problem of under-utilized biomass in this country. Base model was based on previous study. For optimization of mass yield and overall energy consumption, six model options of design configurations were analysed. Design model 0 was used as the base model. For design model 1, flue gas from combustion reactor was channelled to torrefaction reactor. For design model 2, flue gas from combustion reactor was split to dryer and torrefaction reactor. For design model 3, combustion reactor was removed. For design model 4, flue gas was channelled to dryer reactor without combustion reactor. For design model 5, flue gas separator after dryer was removed. Out of five options, results were tabulated for the optimum one. The results showed that the highest mass yield was achieved by simulation Model 5 at 90.76 % and lowest energy requirement was achieved by simulation Model 4 at 411.336 kW. Optimization result meanwhile had shown that Model 4 was selected because it gave the maximum profitability of RM 72834.45 by considering the yield and the energy consumption simultaneously