Circulating Fluidized Bed Reactor Research Articles

Biomass pyrolysis in a circulating fluidized bed reactor: Evaluating two strategies for the reduction of oxygen content in bio-oil

The use of a circulating fluidised bed (CFB) reactor promotes higher heat transfer to the biomass pyrolysis process and has the advantage of being energy self-sufficient through the continuous burning of biochar. CFB’s similarity with the fluidised catalytic cracking (FCC) of fossil streams represents a promising scenario of integration of lignocellulosic biomass in a conventional refining scheme. In this paper, two approaches were studied to enhance the deoxygenation reactions of biomass components in a pilot pyrolysis CFB reactor. First, in a noncatalytic pyrolysis, a lignocellulosic biomass was cofed with hydrogen-rich compounds produced in the oil refinery (methane and propane). In the second part, using a ZSM-5 catalyst in the bed, the effect of different catalyst-to-biomass ratios (CTB) in the bio-oils’ properties was evaluated. Compared with conventional pyrolysis, the cofeeding of methane or propane produced bio-oils with less oxygen content. The use of propane achieved better performance in terms of hydrocarbon concentrations in bio-oils, hence increasing benzene, toluene and xylene (BTX) production and being comparable with the results of catalytic pyrolysis. It was also shown that the increase of CTB in catalytic pyrolysis led to the enhancement of deoxygenation reactions, producing more O-free compounds. Both strategies were promising for improving the quality of bio-oil. Issues such as the cost of the catalyst and gases must be evaluated for possible integration into a conventional refining process.

Investigation of the oxy-fuel combustion process in the full-loop circulating fluidized bed

Oxy-fuel combustion of fossil fuels in circulating fluidized bed (CFB) reactors has been widely implemented in various industries. However, the knowledge of complex gas thermal characteristics (e.g., gas temperature, viscosity, density, conductivity and specific heat capacity) is still in lack. Understanding the distribution of these gas thermal properties within the oxy-fuel combustion CFB reactor is crucial for predicting particle behavior, optimizing operating conditions, and performing design optimizations. In this study, the hydrodynamics and thermochemical characteristics of dense reactive flow in a 0.1 MWth pilot-scale CFB are simulated via a developed multi-phase particle-in-cell (MP-PIC) reactive model. The impacts of some key operating parameters on the gas thermal properties, gas species distribution and gas-solid flux are studied. The results show that the dynamics and thermochemical variables of gas-solid flow show non-uniform distributions in the riser due to the segregation mechanism and lateral injection of solid fuels. Combustible gases (e.g., CH4, CO, H2, and H2S) mainly concentrate in the left area of the riser. Enlarging the oxygen concentration increases gas viscosity while decreases gas density. The density of gas phase ranges from 0.35 kg/m3 to 0.50 kg/m3 while gas turbulent viscosity ranges from 4.2 × 10−5 m2/s to 4.8 × 10−5 m2/s.

Desulfurization Characteristics of Carbide Slag during Circulating Fluidized Bed Coal Combustion

At low loads, the desulfurization efficiency of circulating fluidized bed (CFB) boilers tends to decrease due to the deviation of low bed temperature from the optimal temperature required for limestone desulfurization. However, carbide slag, a waste product rich in Ca(OH)2 and possessing a low decomposition temperature, can be an economically viable alternative to limestone. In this study, the desulfurization characteristics during coal combustion with carbide slag addition were studied both in a fixed-bed reactor and a 30 kW CFB reactor. The effect of different reaction conditions on the desulfurization performance was evaluated. Results showed that the addition of carbide slag decreased SO2 emission effectively. A higher oxygen content prompted the improvement of the desulfurization efficiency. The carbide slag showed the highest desulfurization efficiency at about 800 °C. The desulfurization performance deteriorated when the temperature was beyond 800 °C. To explain this phenomenon, the micromorphology of carbide slag raw particle, calcined particle, and sulfated particle was observed by scanning electron microscopy. More holes formed on the surface of the particles after calcination. Besides, the outer surface of the holes formed more crystal grains with the increasing temperature. CaSO4 products covered the outer surface of the crystal grains after desulfurization. The crystal grain gaps on the surface of carbide slag were easily blocked at high temperatures, which resulted in the low desulfurization efficiency.

Numerical simulation method of a circulating fluidized bed reactor using a modified MP-PIC solver of OpenFOAM

There are some previous works for simulating a bubbling fluidized bed (BFB) reactor using OpenFOAM's MPPICFoam solver, but those for circulating fluidized bed (CFB) reactors are few. In this study, the MPPICFoam solver was verified with a BFB reactor by comparing the solver's simulation results with the experiment and simulation results from the literature. By introducing the inter-boundary particle circulation function and a new module for setting sand particle size distribution, simulations were performed for a 0.1 MW th pilot-scale CFB combustor under isothermal conditions. The modified solver for the CFB reactor gives similar results as the experiment and commercial computational fluid dynamics (CFD) tool, well-predicting the pressure distribution and solid volume fraction in the riser. • MPPICFoam solver reliability for lab-scale bubbling fluidized-bed reactor verified. • Accurate solver prediction of solid volume fraction (horizontal) distribution. • Model used for numerical simulation to study riser hydrodynamics of a CFB combustor. • Particle size distribution module and new circulating boundary conditions added. • Improved solver shows superior predicted experimental results in dense bed region.

3D Unsteady Simulation of a Scale-Up Methanation Reactor with Interconnected Cooling Unit

The production of synthetic natural gas (SNG) via methanation has been demonstrated by experiments in bench scale bubbling fluidized bed reactors. In the current work, we focus on the scale-up of the methanation reactor, and a circulating fluidized bed (CFB) is designed with variable diameter according to the characteristic of methanation. The critical issue is the removal of reaction heat during the strongly exothermic process of the methanation. As a result, an interconnected bubbling fluidized bed (BFB) is utilized and connected with the reactor in order to cool the particles and to maintain system temperature. A 3D model is built, and the influences of operating temperature on H2, CO conversion and CH4 yield are evaluated by numerical simulations. The instantaneous and time-averaged flow behaviors are obtained and analyzed. It turns out that the products with high concentrations of CH4 are received at the CFB reactor outlet. The temperature of the system is kept under control by using a cooling unit, and the steady state of thermal behavior is achieved under the cooling effect of BFB reactor. The circulating rate of particles and the cooling power of the BFB reactor significantly affect the performance of reactor. This investigation provides insight into the design and operation of a scale-up methanation reactor, and the feasibility of the CFB reactor for the methanation process is confirmed.

Research on ethylbenzene dehydrogenation over the Fe-Al-based catalysts in a circulating fluidized-bed unit

BackgroundIn the traditional ethylbenzene dehydrogenation process, much superheated steam is needed to ensure the activity and stability of the catalyst, inevitably leading to high energy consumption. MethodsA novel ethylbenzene dehydrogenation process based on a circulating fluidized bed (CFB) reactor was used for the ethylbenzene dehydrogenation reaction under a low steam-to-oil ratio. In this work, a series of Fe-Al-based catalysts were prepared by a sol-gel method and the effect of alumina content on the catalytic performance of Fe-Al-based catalyst for ethylbenzene dehydrogenation was investigated. Significant findingsAmong a series of Fe-Al-based catalysts, the FeAl40 catalyst (the Fe-Al-based catalyst with 40 wt. % alumina) had the highest dehydrogenation activity and suitable attrition resistance for the CFB reactor. Further investigation found that the adding alumina could inhabit the formation of KFe11O17, leading to poor stability. Interestingly, the high activity of the FeAl40 catalyst could be completely recovered through a reaction-regeneration operation. Compared with the conventional ethylbenzene dehydrogenation process, the CFB process benefits from high activity, low steam-to-oil ratio and no induction period. Consequently, the FeAl40 catalyst had high dehydrogenation activity (∼51 wt. % yield of styrene) and low preparation cost, showing an extraordinary potential for industrial application.

Performance of Fe-Ni-W exchanged zeolite for NOx reduction with NH3 in a lab-scale circulating fluidized bed

Selective non-catalytic reduction of NOx (SNCR) with NH3 is commonly used in industrial facilities like circulating fluidized bed (CFB) furnaces. However, the strongly temperature-dependent de-NOx feature confines its applications in a specific temperature range (900–1050 °C). Here, we report a new strategy on using Fe-Ni-W exchanged zeolite (0.5FNW-H) as a catalyst to extend the SNCR temperature window. In the CFB reactor, a significant NOx conversion improvement ranging from 14.1% to 80.9% was achieved at 700 to 850 °C by applying the developed catalyst. Catalyst dosage of 4500 h−1 (GHSV), a particle diameter of 0.1–0.3 mm, and NH3 injection position at the dense-phase zone were found preferred for NOx reduction with the highest efficiency of ~85% at 700 °C. The physicochemical properties of the catalysts remained stable after the circulating reactions in the CFB reactor. The developed catalyst is particularly applicable for improving the SNCR performance when the thermal power plants are operated at low loads.

Photo-catalytic Ozonation for Degrading Terephthalic Acid in Aqueous Environment

Background & Aims of the Study: Terfetalic Acid (TPA ) is produced in large quantities and used in various industries. Besides, TPA is among the main sources of water pollution in industrialized countries. TPA photo-degradation process was performed in a Circulating Fluidized Bed Reactor (CFBR) by one Ultraviolet type A (UV-A) lamp and ozone generator with MnFe2O4/Willemite photo-catalyst. Materials and Methods: In this research, the nanoparticles of MnFe2O4 and Willemite were synthesized by co-precipitation reactions and wet mixing method, respectively. Then MnFe2O4/ Willemite was synthesized by the immobilization of MnFe2O4 on Willemite by mechanical method. Full factorial experimental design with 4 factors, including the pH, the initial concentration of TPA, the amount of Catalyst (Cat.), and O3 dosage was used for modeling and optimizing the process. Results: In the optimal conditions, the amounts of pH, TPA, Cat., and O3 were obtained equal to 9, 20 ppm, 1.5 g/L, and 2.17 mg/h, respectively. In these conditions, degradation efficiency was obtained to be 98.2695%, and decomposition kinetics was determined as pseudo-first-order with Kapp=0.2707 min-1, kLH=3.729 ppm min-1, and kadd=0.051 ppm-1. Conclusion: Comparing experiments results in different processes, such as UV, UV-Cat, O3, UVO 3, Cat-O3, and UV-Cat-O3 revealed that photo-catalytic ozonation (O3/MnFe2O4/Willemite) in the presence of UV for degradation of TPA in an aqueous environment, present the higher efficiency.

Numerical analysis of the operating characteristics of a large‐scale CFB coal‐gasification reactor with the QC‐EMMS drag model

AbstractThe operating characteristics of a 60 m high industrial circulating fluidized bed (CFB) coal‐gasification reactor were investigated numerically based on the Eulerian‐Eulerian approach. The QC‐EMMS drag model was used to describe the gas‐solid drag reduction caused by particle clusters. The simulations predicted the overall characteristics of fluidization and gasification inside the CFB reactor riser. The simulated results are in agreement with measured data from the field test. Then, the numerical model was used to analyze the influences of the steam/coal ratio, pulverized coal‐particle size, and operating pressure. The results show that each of the three operating parameters has a great impact on different performance parameters, such as the solid mass circulation rate, the H2/CO ratio, the effective syngas yield, and the average bed temperature. The predicted data were then correlated to provide supports for optimizing the operations of large‐scale CFB coal gasifiers.

Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

Abstract The influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

Development and validation of a novel process model for fluidized bed combustion: Application for efficient combustion of low‐grade coal

AbstractNumerous models have been developed in Aspen Plus for the combustion of different coal types in fluidized bed reactors. However, these models are case‐specific, particularly with respect to coal type and bed reactor type, implying limitations to general application of these models. Moreover, these processes were generally developed step‐wisely by employing a series of model blocks to simulate fluidized bed reactors in Aspen Plus. In this study, a novel hybrid approach for modelling coal combustion has been implemented to comprehensively design a model for conversion of low‐grade coal under various operating conditions. The proposed model combines sequential modelling of drying/pyrolysis (devolatilization) and combustion of coal by means of conventionally used units (RYIELD and RGIBBS), and a newly used unit (FLUIDBED) in Aspen Plus. The model validation was performed by experiments on the combustion of low‐grade coal in a pilot‐scale circulating fluidized bed reactor (CFBR). Experimental data were used to further calibrate the Aspen Plus model and decrease model uncertainties. The results obtained from the developed simulation model were found to be in good agreement with the experimental data. Discrepancies of less than 15% were observed, in most of the predictions of molar fractions for the resultant flue gas composition, including NOx and SOx, emissions which were at ppm levels. As a result, the model can easily be used for design, scale‐up, and simulation of coal combustion as well as for other feedstock like biomass in fluidized bed with process optimization based on sensitivity analysis.

Experiment and multiphase CFD simulation of gas-solid flow in a CFB reactor at various operating conditions: Assessing the performance of 2D and 3D simulations

Accurate prediction of gas-solid flow hydrodynamics is key for the design, optimization, and scale-up of a circulating fluidized bed (CFB) reactor. Computational fluid dynamics (CFD) simulation with two-dimensional (2D) domain has been routinely used, considering the computational costs involved in three-dimensional (3D) simulations. This work evaluated the prediction capability of 2D and 3D gas-solid flow simulation in the lab-scale CFB riser section. The difference between 2D and 3D CFD simulation predictions was assessed and discussed in detail, considering several flow variables (superficial gas velocity, solid circulation rate, and secondary air injection). The transient Eulerian-Eulerian multiphase model was used. CFD simulation results were validated through an in-house experiment. The comparison between the experimental data and both computational domains shows that the 3D simulation can accurately predict the axial solid holdup profile. The CFD simulation comparison considering several flow conditions clearly indicated the limitation of the 2D simulation to accurately predict key hydrodynamic features, such as high solid holdup near the riser exit and riser bottom dense region. The accuracy of 2D and 3D simulations was further assessed using root-mean-square error calculation. Results indicated that the 3D simulation predicts flow behavior with higher accuracy than the 2D simulation.

Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating fluidized beds

Dual-loop circulating fluidized bed (CFB) reactors have been widely applied in industry because of their good heat and mass transfer characteristics and continuous handling ability. However, the design of such reactors is notoriously difficult owing to the poor understanding of the underlying mechanisms, meaning it has been heavily based on empiricism and stepwise experiments. Modeling the gas-solid CFB system requires a quantitative description of the multiscale heterogeneity in the sub-reactors and the strong coupling between them. This article proposed a general method for modeling multiloop CFB systems by utilizing the energy minimization multiscale (EMMS) principle. A full-loop modeling scheme was implemented by using the EMMS model and/or its extension models to compute the hydrodynamic parameters of the sub-reactors, to achieve the mass conservation and pressure balance in each circulation loop. Based on the modularization strategy, corresponding interactive simulation software was further developed to facilitate the flexible creation and fast modeling of a customized multi-loop CFB reactor. This research can be expected to provide quantitative references for the design and scale-up of gas-solid CFB reactors and lay a solid foundation for the realization of virtual process engineering.

Numerical simulations and comparative analysis of two- and three-dimensional circulating fluidized bed reactors for CO2 capture

Carbon dioxide (CO 2 ), the main gas emitted from fossil burning, is the primary contributor to global warming. Circulating fluidized bed reactor (CFBR) is proved as an energy-efficient method for post-combustion CO 2 capture. The numerical simulation by computational fluid dynamics (CFD) is believed as a promising tool to study CO 2 adsorption process in CFBR. Although three-dimensional (3D) simulations were proved to have better predicting performance with the experimental results, two-dimensional (2D) simulations have been widely reported for qualitative and quantitative studies on gas–solid behavior in CFBR for its higher computational efficiency recently. However, the discrepancies between 2D and 3D simulations have rarely been evaluated by detailed study. Considering that the differences between the 2D and 3D simulations will vary substantially with the changes of independent operating conditions, it is beneficial to lower computational costs to clarify the effects of dimensionality on the numerical CO 2 adsorption runs under various operating conditions. In this work, the comparative analysis for CO 2 adsorption in 2D and 3D simulations was conducted to enlighten the effects of dimensionality on the hydrodynamics and reaction behaviors, in which the separation rate, species distribution and hydrodynamic characteristics were comparatively studied for both model frames. With both accuracy and computational costs considered, the viable suggestions were provided in selecting appropriate model frame for the studies on optimization of operating conditions, which directly affect the capture and energy efficiencies of cyclic CO 2 capture process in CFBR.

Oxidation mechanism of pyrite concentrates (PCs) under typical circulating fluidized bed (CFB) roasting conditions and design principles of PCs’ CFB roaster

The circulating fluidized bed (CFB) roasting process is a promising way to utilize pyrite concentrates (PCs) which are byproducts in nonferrous metal production processes. The oxidation mechanism of PCs was investigated under typical CFB roasting conditions with the temperature of 850 °C and oxygen concentration of 1–21% on a drop tube furnace. The oxidation reaction pathway and products of PCs are strongly coupled with particle morphology evolution, which affects the oxygen diffusion from the particle surface to the core. A reaction path model of PC oxidation coupled with particle morphology evolution under CFB roasting conditions was proposed. The initial relatively slow oxidation of the porous particle structure followed by the relatively fast oxidation for complete oxidation was demonstrated to be the ideal reaction path for the CFB roasting operation of PCs. The critical issue for PCs roasting in the CFB reactor is to inhibit the particle temperature rise in dense phase region to avoid the formation of compact solid spheres. The flow and reaction behaviors of PC particles in CFB reactor naturally follow the ideal reaction path and make the CFB roasting technology feasible. Finally, the design principles of PCs CFB roasting process were suggested.

Simulations of sorbent regeneration in a circulating fluidized bed system for sorption enhanced steam reforming with dolomite

In this work, the sorption enhanced steam reforming (SESR) method was developed for improved hydrogen (H2) production, and the drawbacks of conventional steam reforming processes on H2 yield and purity were overcome. However, the SESR process is discontinuous and requires regeneration after sorbent saturation with CO2. The circulating fluidized bed reactor (CFBR) system has previously been proposed for continuous H2 production, with both reforming and sorbent regeneration occurring simultaneously. The main aim of this work was to determine the feasibility and performance of SESR with a proper design and conditions in conjunction with the CFBR system. The reforming riser and bubbling bed regenerator are studied separately but related to each other. Two-dimensional transient models using the Euler‒Euler approach and kinetic theory of granular flow were used for fluid dynamic simulations combined with the decarbonation kinetics of dolomite, to investigate a conceptual regenerator system and determine its key conditions. A mixture of the Ni-based catalyst and dolomite from the risers was injected with a flux of 200kg/(m2s) and a catalyst to sorbent ratio of 2.54kg/kg. A double-stage bubbling bed regenerator system was designed with 1.2m width, 0.8m bed height, a gas inlet velocity of 0.2m/s and solid preheating at 950°C. The used dolomite was regenerated with an assumed CaO conversion of 3%; the almost fresh dolomite was then released with good mixing of the catalyst and sorbent.

Improving circulating fluidized bed dehydrogenation technology through optimization of fluidization

The dehydrogenation of light alkanes to corresponding light olefins is an important industrial process. The present work involved the assessment of a commercial alkane dehydrogenation circulating fluidized bed (CFB) reactor unit that had been underperforming and exhibiting higher than expected catalyst losses over a long period of time. Several aspects of this unit related to fluidization, catalysis, and process engineering were investigated to understand and resolve these issues. The primary focus was on the fluidization aspects of the process, along with a comparison of equipment design and operating conditions to accepted best practices in the industry. The designs of key equipment in the reactor and regenerator, including feed distributors, fuel gas distributors, cyclones, baffles, strippers, transfer lines, risers, riser terminations, and refractories, were studied in detail. The attrition rates of different types of catalysts used in the unit were also examined. Several recommendations and improvement opportunities were proposed to significantly increase light olefins production and reduce catalyst losses, and were accepted and implemented. This study provides insights into means of improving fluidization behavior and highlights the viability of employing a systematic approach to determine the underlying root causes of issues in a commercial CFB reactor unit.

CFD simulations of a full-loop CFB reactor using coarse-grained Eulerian–Lagrangian dense discrete phase model: Effects of modeling parameters

The hydrodynamics of a 3D full-loop circulating fluidized bed (CFB) reactor were investigated using a coarse-grained dense discrete phase model (DDPM). The effects of changes in key modeling parameters such as the drag force, particle number per parcel, and particle–particle/particle–wall restitution coefficients were thoroughly investigated. Previous experimental data were used as a benchmark for validating the numerical results. In terms of the drag force, the simulation results show that the effect of mesoscale structures on drag force must be considered in the DDPM approach. Regarding the number of particles per parcel, the predictions indicate parcel-independent behavior at all of the coarse-graining ratios tested (dcl/dp = 55, 95, and 125), which is further proof that parcel-independent results can be achieved when the parcel diameter is in the size range of clusters. The effect of energy dissipation from particle–particle (epp) collisions shows that better results are generated when epp is in the non-ideal range (0.1–0.9) than for the ideal case (epp = 1.0). However, the particle–wall restitution coefficient (epw) has little effect on hydrodynamic behavior in either the ideal or non-ideal collision range. In addition, the effect of the particle size distribution on the full-loop hydrodynamics was investigated. The predicted results are similar to those from mean particle diameter simulations, but the distributions for different particles in the CFB are different. This would certainly affect the heat and mass transfer and reactions, and will be further investigated in our ongoing simulations of combustion in CFBs.

Circulating turbulent fluidized bed regime on flow regime diagram

Circulating turbulent fluidized bed (CTFB) regime was recently found under a low superficial gas velocity (Ug) system and contained the advantages of both a conventional turbulent fluidized bed, with an excellent mixing property between the gas and solid phases due to the high solid volume fraction (SVF), and a fast fluidized bed (FFB) or circulating fluidized bed (CFB) regime, which could be employed in a continuous mode. To observe the new flow regime, it was conducted in a plexiglas two-dimensional CFB reactor with a riser of 2.00 m height, 0.15 m width and 0.05 m depth. The interpretation of the SVF profiles along the riser height were used to determine the appearance the tubulent bed front where the turbulent bed was terminated. The identification of the CTFB was a profile without the appearance of a bed front in the riser. In conclusion, the development of a CTFB regime was caused by the turbulent bed expansion, which was affected by the magnitude of Ug. There were three important criteria to perform a CTFB: a solid recirculating rate of at least 300 kg/m2.s, the regulated Ug should be between a bubbling fluidized bed (Uc) and FFB (Utr), and lastly, the most important design parameter, the riser height must be shorter than the maximum turbulent bed expansion, which depends on the choice of solid particles. The functions that showed a good agreement with the experimental results were applied to obtain the correlations that later became the compulsory part of addressing the boundaries for each fluidized bed regime. The advantage of the new flow regime diagram was that it included the aspects of operation and design if CTFB was the desire.

Fast pyrolysis from Napier grass for pyrolysis oil production by using circulating Fluidized Bed Reactor: Improvement of pyrolysis system and production cost

This article focused on production cost of pyrolysis oil production of Napier Grass in Circulating Fluidized Bed Reactor (CFBr) which sand was used as bed material. The Napier grass was converted to pyrolysis oil by using fast pyrolysis process. The reactor temperature, superficial velocity (Uf) and feed rate of feedstock were adjusted in order to find the best condition of this experiment, and the Quadratic Response Model was used to predict the yield of pyrolysis oil and the optimum condition coupled with the experiment. From a results of this experiment, it was found that the maximum pyrolysis oil production was 36.93 wt% at 480 ºC of bed temperature, 7 m/s of superficial velocity and 60 kg/hr of feed rate, while the result from the Quadratic Response Model indicated that the maximum pyrolysis oil production was 32.97 wt%. From the analysis of properties of pyrolysis oil, results showed that heating value, density, viscosity, pH and water content were 19.79 MJ/kg, 1,274 kg/m 2.32 cSt, 2.3 and 48.15 wt%, respectively, and the ultimate analysis was also determined. From the analysis of the efficiency of energy conversion, it was concluded that the value of cold efficiency and total energy conversion to pyrolysis oil in this system were 24.88% and 19.77%, respectively. The greatest energy consumption in this system was made by the energy from the heating process. Furthermore, from the calculation result of production cost in this study, it was concluded that a production cost of pyrolysis oil was 0.481 $/liter or 9.88 $/GJ at the 75 kg/hr of feed rate.