Oil Palm Shell Research Articles

Bio-graphene production from oil palm shell waste valorised through sequential thermal and catalytic means

Cellulose, hemicellulose and lignin made up a large majority of biomass in the world. These three organic polymers can produce bio-gas such as methane (CH4) and carbon dioxide (CO2) which are necessary for bio-graphene fabrication. Carbon layer deposition depends on CH4 while the uniformity and porosity of the carbon layer depend on CO2 and activation agent interaction. By altering the Oil Palm Shell (OPS) biomass precursor through pyrolysis, the remaining content of biomass precursors will enhance bio-graphene development through Chemical Vapor Deposition (CVD) process. The alteration of these biomass precursors is made through thermal manipulation at temperatures of 200 ∘C, 400 ∘C and 600 ∘C. The best thermal means will produce bio-graphene encompassing observable crystallinity, appropriate exfoliation, low defect, high carbon and low oxygen value which possess characteristics that are similar to bio-graphene fabricated from the past years. The different pre-treated biomass through pyrolysis are characterized using proximate analysis, Fourier-transform infrared spectroscopy (FTIR), Field-Emission Scanning Electron Microscope (FESEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Micro-Raman. Additionally, the different bio-graphene samples fabricated from pre-treated biomass precursors were identified and characterized using Atomic Force Microscopy (AFM), Ultra-high Resolution Scanning Electron Microscope (U-SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Micro-Raman spectrometer.

Bio-oil from Oil Palm Shell Pyrolysis as Renewable Energy: A Review

Bio-oil from Oil Palm Shell Pyrolysis as Renewable Energy: A Review

Model Persebaran Emisi pada Pembangkit Listrik Tenaga Uap Berbahan Bakar Serat dan Cangkang Kelapa Sawit Menggunakan Perangkat Pemodelan Aermod

According to the Republic Indonesia government regulation to reduce greenhouse gas emissions by 29% independently and 41% with international assistance in 2030, then to achieve the target of net zero emissions by 2060 in accordance with the COP27 Climate Change Conference in Egypt in 2022, it is necessary to found renewable energy sources with low emission levels. Renewable energy sources with low emission levels that are quite popular and available are those from palm oil waste biomass such as oil palm empty fruit bunches, fibre and oil palm shells. This study aimed to determine the emission dispersion modelling from the combustion of fibre and palm kernel shells mixture with ratio 60% and 40% at two steam power plants with a capacity of 30 tons/hour and 20 tons/hour, respectively, using Aermod Modelling System. The emission load calculated using combustion mass balance calculation method. Mass balance calculation result showed that the emission content from the two chimneys is 134.76 mg/m3 for the NO2 parameter; 13.11 mg/m3 for the SO2 parameter and 37.31 mg/m3 for the particulate parameter. Meanwhile, for emission dispersion, the highest emission level occurs at coordinates X = 200319.12 and Y = 9817175.03, which is the closest coordinate to the emission source where the highest value at that location for the NO2 parameter is 241.18 µg/m3, the SO2 parameter is 15.29 µg/m3 and particulate parameters of 66.91 µg/m3. The distribution of emission dispersion tends to be southeast and north according to the wind direction at the study site..

Magnetite Particle Coating to Activated Carbon of Oil Palm Shells as Adsorbent of Cu(II) and Ni(II) Cation

Magnetite Particle Coating to Activated Carbon of Oil Palm Shells as Adsorbent of Cu(II) and Ni(II) Cation

Strength Properties and Toughness Indices of Hybrid Polymeric Fibre Reinforced Renewable Oil Palm Shell Concrete

In this study, the strength properties and durability of polymeric fibre-reinforced concrete containing renewable oil palm shell (ROPS) lightweight aggregate were investigated. The effect of individual Polyvinyl Alcohol (PVA) fibre, individual Polypropylene (PP) fibre and hybrid PVA-PP fibre with various percentage of volume fraction, Vf (0, 0.3 and ‘0.25+0.05’%) on the compressive strength and toughness indices of ROPS LWC were examined. The research outcomes show that compressive strength of ROPS lightweight concrete strengthened with individual PVA fibre or PP fibre enhanced with the increase of Vf fibre. From the results, toughness indices increased significantly by 38.3% compared to control mix. Furthermore, the hybrid ‘PVA0.25/PP0.05’ had revealed the optimum results as associated to other mixes. Thus, the outcomes of this paper showed that the blend of both PVA and PP polymeric fibre could potentially be utilized in concrete industry.

Co-pyrolysis and co-combustion of orange peel and biomass blends: Kinetics, thermodynamic, and ANN application

Co-pyrolysis and co-combustion of orange peel, oil palm shell, and empty fruit bunch biomass with and without blends were investigated in a thermogravimetric analyzer (TGA) at 5, 10, 15, and 20 °C/min heating rate. The kinetic parameters were calculated using the model-free and model-fitting methods. Results showed that blending altered the thermogravimetry (TG) and derivative thermogravimetry (DTG) profiles and indicated the existence of multiple reactions. Biomass blends showed a strong synergetic effect, specifically during the char formation. The average activation energy was a function of conversion degree, and the values for the biomass blends were 82–120 kJ/mol compared to their parent biomass (64–111 kJ/mol). The trained artificial neural network model predicted the TG profiles of biomass blends with high R2 values (≥0.9), but the prediction accuracy was relatively poor for DTG profiles (≤0.8). Overall, mixing orange peel waste and oil palm biomass altered the thermo-chemical behavior and kinetics, which could develop a new dimension for future studies.

Compressive strength prediction of high-strength oil palm shell lightweight aggregate concrete using machine learning methods.

Promoting the use of agricultural wastes/byproducts in concrete production can significantly reduce environmental effects and contribute to sustainable development. Several experimental investigations on such concrete's compressive strength ([Formula: see text]) and behavior have been done. The results of 229 concrete samples made by oil palm shell ([Formula: see text]) as a lightweight aggregate ([Formula: see text]) were used to develop models for predicting the [Formula: see text] of the high-strength lightweight aggregate concrete ([Formula: see text]). To this end, gene expression programming ([Formula: see text]), adaptive neuro-fuzzy inference system ([Formula: see text]), artificial neural network ([Formula: see text]), and multiple linear regression ([Formula: see text]) are employed as machine learning ([Formula: see text]) and regression methods. The water-to-binder ([Formula: see text]) ratio, ordinary Portland cement ([Formula: see text]), fly ash ([Formula: see text]), silica fume ([Formula: see text]), fine aggregate ([Formula: see text]), natural coarse aggregate ([Formula: see text]), [Formula: see text], superplasticizer ([Formula: see text]) contents, and specimen age are among the nine input parameters used in the developed models. The results show that all [Formula: see text]-based models efficiently predict the [Formula: see text]'s [Formula: see text], which comprised [Formula: see text] agricultural wastes. According to the results, the [Formula: see text] model outperformed the [Formula: see text] and [Formula: see text] models. Moreover, an uncertainty analysis through the Monte Carlo simulation (MCS) method was applied to the prediction results. The growing demand for sustainable development and the crucial role of eco-friendly concrete in the construction industry can pave the way for further application of the developed models due to their superior robustness and high accuracy in future codes of practice.

Aktivitas Antibakteri Hand Sanitizer Berbahan Dasar Asap Cair Hasil Torefaksi Cangkang Kelapa Sawit Terhadap Bakteri Escherichia coli

Antibacterial activity of hand sanitizer based on liquid smoke from torrefaction of palm oil against Escherichia coli has been done. The liquid smoke produced from the oil palm shell torrefaction process has the potential to be used as an antiseptic base for hand sanitizer products. This is due to its high phenol and acetic acid content. Many other compounds must be separated from liquid smoke, one of the processes that can be separated with distillation. Compounds of liquid smoke from distillation are phenol, propanoic acid, 2-propanone, and acetic acid. This research was conducted by varying the concentration of liquid smoke in a hand sanitizer by 15%, 25%, and 35%. The results showed that the number of bacterial colonies at a concentration of 15% was 910,000 CFU/ml, 25% was 1,130,000 CFU/ml, and 35% was 1,140,000 CFU/ml. The effective concentration to kill bacteria is in hand sanitizer based on liquid smoke with a concentration of 15% was 57,59%.
 Keywords: palm kernel shells, liquid smoke, Escherichia coli

Experimental Prognostication of Ultra-High-Performance Lightweight Hybrid Fiber-Reinforced Concrete by Using Sintered Fly Ash Aggregate, Palm Oil Shell Aggregate, and Supplementary Cementitious Materials.

To create cost-effective structures, the modern construction industry has sought to reduce the dead load of buildings. Lightweight concrete is a quick way to reduce dead load. The current study is primarily concerned with identifying modern substitutes for coarse aggregate likely to aid in waste management and offer potential alternatives to the most exploited natural resources. According to ACI C 39-M, this study developed a novel lightweight hybrid fiber-reinforced concrete (LWHFRC) with a density of less than 1825 kg/m3 and compressive strength of 50 to 75 MPa. Ordinary Portland cement (53 Grade) was mixed with fly ash, silica fume, and GGBS. Sintered fly ash aggregate (SFA) and palm oil shell aggregate (POS) were used as coarse aggregates. Hooked steel fibers and polyvinyl alcohol fibers were combined in a hybrid form to improve crack propagation properties at the initial and subsequent stages. The water-to-binder ratio was kept constant at 0.30 to 0.35 with a 1% superplasticizer. Four volume fractions of hybrid fibers (both steel and PVA with Vf = 0%, 1%, 1.5%, and 2%) were added. In addition, XRD, SEM, EDS, and EDS mapping tests were performed to finalize the material’s chemical composition and crystalline structure. Furthermore, beams and cylinders were tested to determine the modulus of rupture, which was determined to be between 9.5 and 14 MPa by ACI code C 1609-M, and indirect tensile strength, achieved as 10 to 14 MPa by ACI code C 496-M. The researcher altered the modulus of elasticity (Ec) formula for lightweight concrete and discovered a relationship between fc’ and fcb, fc’ and fspt, and fcb and fspt. Finally, ANOVA and regression tests were run to check the significance of the experiment. The cost analysis revealed that the cost of LWHFRC increased by approximately 16.46%, while the strength increased by 55.98% compared to regular concrete.

PENGARUH APLIKASI ASAP CAIR CANGKANG KELAPA SAWIT PADA TANDAN BUAH SEGAR TERHADAP KUALITAS MUTU CPO (CRUDE PALM OIL)

The results showed that liquid smoke grade 2 of palm oil shells were able to reduce the content of free fatty acids in crude palm oil. The results of the best free fatty acid levels found in the sample of the spray treatment method decreased by 0.38% and the combination decreased by 0.52%, the results obtained were greatly decreased and met the Indonesian National Standard 01-2901-2006. The water content and dirt content produced are still very high, the lowest average water content is obtained by sample B2 with a result of 0.94% and the highest average result is obtained by sample A, which is 0.99% and the result of dirt content with an average result The lowest average was obtained by sample B with a result of 1.38% and the highest average result was obtained by sample B2 with an average result of 4.2%. The results of high water content and dirt content were caused by obtaining crude palm oil by pressing using a manual tool with a cloth so the results obtained did not meet the Indonesian National Standard 01-2901-2006, namely 0.5%. Then the results of DOBI levels (Deterioritation Of Bleachability Index) were obtained with the lowest result of 2.56 from the results of sample B1 and the highest result of 2.25 ppm from the results of B3, if it is associated with the quality of the oil obtained is still not sufficient, it is still not meeting the standards set. determined by PORIM (Palm Oil Research Institute of Malaysia) which is 2.36 – 3.24. For the level of carotene produced, it is still not enough, namely, the lowest average result is 4.26 ppm from sample B3 and the highest average result is obtained by sample A, which is 488 ppm, so it still does not meet the quality standards of carotene parameters according to Palm Oil Refiners. Association of Malaysia (PORAM) which is 500 - 700 ppm.

Pemanfaatan Biomassa Padat Kelapa Sawit Sebagai Energi Baru Terbarukan DI PLTU Pabrik Kelapa Sawit PT. Perkebunan Nusantara VI Unit Usaha Bunut

Palm oil is one of the choices of growth companies in Indonesia as biomass energy. Biomass is organic matter made from plants and animals that contain energy. The result of the palm oil processing process is liquid and solid waste.Liquid waste in the form of sludge can be reprocessed into pure palm oil with several treatments.Solid waste in the form of shells and fibers (fibre) derived from palm pulp is used as fuel in boilers and used as steam steam for the process of generating electricity through turbines. Research on the utilization of solid palm oil waste fibers and shells was carried out at PT. Nusantara Plantation VI PKS Bunut because of its large waste potential as an alternative fuel source (renewable energy. Processing capacity of the plant of 30 tons of FFB/hour produces 3.9 tons of fiber solid waste and 2.1 tons of shells, the total solid waste as fuel is 6 tons/hour. The fuel requirement of the plant is 4.55 tons/hour so that there is a difference of 1.45 tons/hour. The electrical energy generated from the utilization of 6 tons/hour of fuel is 776 kW/Hour, while the realization energy used by the factory is 750 kWh/Hour.There is an excess energy of 2.6 kW/hour. This indicates that the use of shells and fibers as fuel for new and renewable energy at the PLTU PKS Bunut PT. Nusantara VI plantations are very good.

Production of Fuel pellet From Agricultural And Plantation Estate Crops Biomass

Biomass contains energy used as solid fuel so that biomass will have high added value. Directly combustion of biomass has caused environmental pollution problems. Agricultural and plant estate plantation biomass waste that is widely spread in Indonesia needs to be utilized. The research was aimed at designing and producing biomass pellets for a pilot-scale capacity of 200 kg/hour. The biomass used consisted of empty oil palm fruit bunches (OPEFB), oil palm shells (OPS), cocopeat, corn cobs, and sugar cane bagasse. Pellets are formed by pressing biomass powder with high pressure using a 10 hp pelletizer. The quality of pellets produced was tested based on the standard DIN 53731. The performance test of pelletizing machinery showed that such types of machinery could be produced for 150-200 kg/hour. The test results showed that almost all quality parameters of biomass pellet (moisture content, calorific value, ash content, density, length, and diameter) met the requirements. Synthetic gas produced from burning biomass pellets in the gasifier and stove is able to use for drying and heating for 80 minutes. Pelletizing can enhance the volumetric and calorific value, reduce the transport and storage costs, reduce the moisture content, and improve the handling characteristics of biomass.

The Effect of Microwave Oven Power Variations on Co-Pyrolysis Process of Oil Palm Shells and Polystyrene

Indonesia has a very large area of ​​oil palm plantations, one of which is the island of Sumatra. However, in processing and handling palm oil product waste in the form of palm shells, it has not been maximized. Therefore, the chemical decomposition process can play an important role in supporting waste management and sustainable energy use in Indonesia which is not yet optimal. In this research, the proper use of power will be tested with the help of microwaves as a reactor for the co-pyrolysis process of oil palm shells and polystyrene plastic. The purpose of this study was to determine the appropriate power to produce maximum co-pyrolysis products and to investigate the physical characteristics of the oil-pyrolytic products. The test uses a microwave oven which has a power variation of 300 W, 450 W, 600 W, and 800 W with the addition of a catalyst. The ratio of the composition of oil palm shells to polystyrene plastic is 1:1 with a total mass of 105 gr and using coconut shell charcoal as an activated carbon absorber. The pyrolysis temperature is 500 ℃, the nitrogen gas flow rate is 1.5 LPM, and the pyrolysis time is 60 minutes. Furthermore, testing the physical properties of the pyrolysis oil product in the form of density, acidity, and viscosity testing. The results showed that the optimal power to obtain oil-pyrolytic was 600 W with a product oil of 17.6%, and from the physical properties it had a low viscosity value of 2.55 mPa.s with a pH level of 6.6.

Characteristics of Carbon from Oil Palm Shell Activated by Low Concentration of Zinc Chloride Activator

Currently, a large amount of oil palm shell has been dumped as waste from palm oil processing in Indonesia. Using a low concentration of zinc chloride (ZnCl2), thermal treatment during pre-carbonization was applied in the preparation of activated carbon from oil palm shells at various temperatures and reaction durations. This study, therefore, aims to investigate the physical and chemical characteristics of activated carbon prepared. Oil palm shells collected from a plantation in Palembang were carbonized by two methods, one-stage carbonization (at 300°C for 3 hours) and two-stage carbonization (at 300°C for 3 hours, then at 600°C for an hour) before chemical activation using ZnCl2, at a concentration of 10 and 15%wt. Activation of oil palm shell charcoal was conducted at 600, 700, and 800°C and reaction times of 60, 120, and 180 minutes. The results showed two-stage carbonization, high temperature, and prolonged reaction time is bound to increase burn-off as well as methylene blue adsorption, and decrease the yield and volatile matter content of the activated carbon prepared. Meanwhile, high ZnCl2 concentration increased the ash content and the methylene blue adsorption. In addition, the two-stage carbonization had higher iodine adsorption compared to the one-stage carbonization. The activated carbon with high iodine (769.3 mg/g) and methylene blue adsorption (133.7 mL/g) levels was obtained by two-stage carbonization using 15%wt ZnCl2 at a temperature and reaction time of 800°C and 180 minutes, respectively.

Pembuatan bio-briket dari produk pirolisis biochar cangkang kelapa sawit sebagai sumber energi alternatif

Fossil fuel sources are non-renewable energy sources and someday will experience scarcity due to the increasing population; it is necessary to look for alternative fuels. Several renewable energies that can replace fossil fuels are water, solar energy, wind, thermal energy, and biomass energy. One biomass energy from plantations is biomass from oil palm plantation waste. Riau Province is Indonesia's largest palm oil producer, with a total land area of ​​2.89 million until 2021. The results of harvesting coconuts will produce waste, i.e., oil palm shells. Oil palm shells can be treated with pyrolysis technology. In the pyrolysis process, three products are produced: liquid, solid (biochar), and oil products (bio-oil). In this study, the pyrolysis product of oil palm shell waste in the form of biochar was used as raw material to produce bio-briquettes. Producing bio-briquettes resulted from pulverized biochar pyrolysis, mixed with tapioca flour adhesive with a percentage of 4% and 8%. Then, the biochar mixture with adhesive was put in a mold and compressed. The results of the bio-briquettes were tested for water content, ash content, volatile matter content, and calorific value. The test results were compared with the Indonesian National Standard (SNI) 8021 2014. The research results on bio briquettes from the pyrolysis of palm oil shell waste showed the best results at 4% reactant content with 4.45% water content, 5.1% ash content, volatile matter content 40.40%, and the calorific value was 5,999.93 cal/gram.

A Sustainable Reuse of Agro-Industrial Wastes into Green Cement Bricks.

The fabrication of bricks commonly consumes relatively high natural resources. To reduce the carbon footprint in the brick production industry, repurposing industrial wastes in the making of sustainable bricks is a recent trend in research and application. Local wastes, such as oil palm shell (OPS), palm oil fuel ash (POFA), and quarry dust (QD), are massively produced annually in the palm oil-exporting countries. Moreover, QD from mining industries is hazardous to both water and air quality. For better waste management in marching towards sustainability, these wastes should be given their second life as construction materials. Therefore, this paper investigates the possibility of incorporating agro-industrial wastes into the brick mixture by examining their properties by means of several standardized tests. For the mix design, a 100% replacement of coarse aggregate with OPS, 20% replacement of cement with POFA, 20% cement weight of limestone as admixture, and 0 to 50% replacements of fine aggregate with QD are experimentally considered. The optimum mix of these wastes is preliminarily determined by focusing on high compressive strength as an indicator. Other examinations include splitting tensile, flexural strength, water absorption, and efflorescence tests. Although the agro-industrial waste cement brick is 18% lower in the strength to weight ratio compared to that of conventional, it is observed that it has better late strength development due to its POFA pozzolanic properties. Moreover, the proposed green cement brick is further checked for compliance with several standards for feasible use in the construction industry. Financially, the cost for the brick with the new mix design is almost equivalent to that of conventional. Hence, this green cement brick is reasonable to be employed in the construction industry to promote material sustainability for better waste management.

MECHANICAL PROPERTIES AND FRACTURE PREDICTION OF CONCRETES CONTAINING OIL PALM SHELL AND EXPANDED CLAY FOR FULL REPLACEMENT OF CONVENTIONAL AGGREGATES

In order to reduce the continual depletion and exploitation of natural resources, this paper examines the mechanical properties and fracture prediction of sustainable lightweight aggregates concretes comprising agro-industrial waste or/and artificial aggregate, considering a full replacement of conventional coarse aggregate. The fresh and hardened properties are examined, from which three out of the five design mixes can achieve structural concrete specifications. It is observed that compression, tensile, and flexural strengths of the mixes exhibit a similar behaviour trend, as relatively higher values can be obtained from homogenous coarse aggregates compared to heterogeneous aggregates for different proportions of oil palm shell (OPS) and expanded clay replacement. The experimental results showed compression strength of 13 to 32 MPa, splitting tensile strength of 1.32 to 2.97 MPa and flexural strength of 1.67 to 5.24 MPa for the investigated mixes at concrete age of 28 day. Most of the mixes able to achieve structural use. Amongst the mixes, those containing expanded clay lowered the corresponding sorptivity values. Although statistics prove that the prediction models of tensile and flexural strengths can represent existing experimental findings, further investigations are recommended for a better properties forecasting of lightweight aggregate concrete containing OPS and expanded clay.

Performance of surface modification on bio-based aggregate for high strength lightweight concrete

The utilization of wastes in concrete as bio-based aggregate can alleviate disposal issues as well as preserve precious natural resources. This research highlights the wet grout binder derived from different water-cement ratios (0.65, 0.85, 1.05, and 1.25) in modifying the surface of lightweight bio-based coarse aggregate (LWBCA). In this research, the strength properties of lightweight aggregate concrete (LWAC) mixed with modified LWBCA were evaluated. The outcomes showed that through the replacement of non-treated bio-based aggregate with that of pre-treated grout coating bio-based aggregate, the density of the samples slightly increased. The results indicated that the slump value of the treated LWBCA showed a significant enhancement by almost 45% at 10 min for treated dura oil palm shell at 0.65 water-cement ratios (TDOPS/0.65), as compared to the non-treated bio-based aggregate. In addition, the strength of the TDOPS/0.65 mix shows more appropriate quality enhancement of pre-treated LWBCA when compared to non-treated, and correspondingly the strength properties of the concrete, particularly the significant increment of compressive strength and elastic modulus were recorded at 21% and 31%, respectively. Based on the water absorption test assessment, the LWBCA concrete indicated that good concrete was obtained for all the mixes. Therefore, a new technique of surface modification on bio-based aggregate has shown to be a highly suggested method, which performs as one of the most promising solutions to enhance the interfacial bonding strength. Thus, treatment improves the bio-aggregates to a level without scarifying the quality of the LWAC and substantially mitigating the environmental impact in concrete.

Enhancement of the Mechanical, Self-Healing and Pollutant Adsorption Properties of Mortar Reinforced with Empty Fruit Bunches and Shell Chars of Oil Palm.

This study aims to produce mortar through the addition of oil palm shells (OPS)-activated charcoal and oil palm empty fruit bunch (OPEFB) hydrochar, which has high mechanical properties, self-healing crack capabilities, and pollutant adsorption abilities. The cracking of mortar and other cementitious materials is essential in anticipating and reducing building damages and ages due to various reasons, such as chemical reactions, foundation movements, climatic changes, and environmental stresses. This leads to the creation of self-healing mortar, which is produced by adding reductive crack size materials to form calcium carbonate (CaCO3) and silicate hydrate (3CaO.2SiO2.2H2O, CSH). One of these materials is known as activated charcoal, which is obtained from oil palm shells (OPS) and oil palm empty fruit bunches (OPEFB) fibres. This is because the OPS-activated charcoal minimizes crack sizes and functions as a gaseous pollutant absorber. In this study, activated charcoal was used as fine aggregate to substitute a part of the utilized sand. This indicated that the utilized content varied between 1–3 wt.% cement. Also, the mortar samples were tested after 28 days of cure, including the mechanical properties and gaseous pollutant adsorption abilities. Based on this study, the crack recovery test was also performed at specific forces and wet/dry cycles, respectively, indicating that the mortar with the addition of 3% activated charcoal showed the best characteristics. Using 3% of the cement weight, OPEFB hydrochar subsequently varied at 1, 2, and 3% of the mortar volume, respectively. Therefore, the mortar with 3 and 1% of OPS-activated charcoal and OPEFB hydrochar had the best properties, based on mechanical, self-healing, and pollutant adsorption abilities.

Exergy Analysis of Alternative Configurations of Biomass-Based Light Olefin Production System with a Combined-Cycle Scheme via Methanol Intermediate

Thermodynamic performance of three conceptual systems for biomass-derived olefin production with electricity cogeneration was studied and compared via exergy analysis at the levels of system, subsystem and operation unit. The base case was composed of the subsystems of gasification, raw fuel gas adjustment, methanol/light olefin synthesis and steam & power generation, etc. The power case and fuel case were designed as the combustion of a fraction of gasification gas to increase power generation and the recycle of a fraction of synthesis tail gas to increase olefin production, respectively. It was found that the subsystems of gasification and steam & power generation contribute ca. 80% of overall exergy destruction for each case, of which gasifier and combustor are the main exergy destruction sources, due to the corresponding chemical exergy degrading of biomass and fuel gas. The low efficiency of 33.1% for the power case could be attributed to the significant irreversibility of the combustor, economizer, and condenser in the combined-cycle subsystem. The effect of the tail gas recycle ratio, moisture content of feedstock, and biomass type was also investigated to enhance system exergy performance, which could be achieved by high recycle ratio, using dry biomass and the feedstock with high carbon content. High system efficiency of 38.9% was obtained when oil palm shell was used, which was 31.7% for rice husk due to its low carbon content.