Steam Injection Research Articles

A New Method to Reduce Shale Barrier Effect on SAGD Process: Experimental and Numerical Simulation Studies using Laboratory-Scale Model

Summary Shale barrier has been widely reported in many steam-assisted gravity drainage (SAGD) projects. For an SAGD project, the properties and distribution of shale barrier can significantly impede the vertical expansion and lateral spread of steam chamber. Currently, although some literature has discussed the shale barrier effect from different perspectives, a systematic investigation combining the scaled physical and numerical simulations is still lacking. Simultaneously, how to reduce the shale barrier effect is also challenging. In this study, aiming at the Long Lake oilsands resources, combining the methods of 3D experiment and numerical simulation, a new method based on a top horizontal injection well is proposed to reduce the impact of shale barrier on the SAGD process. First, based on a dimensionless scaling criterion of gravity-drainage process, we conducted two 3D gravity-drainage experiments (base case and improved case) to explore the effect of shale barrier and the performance of top injection well on SAGD production. During experiments, to improve the similarity between the laboratory 3D model and the field prototype, a new wellbore model and a physical simulation method of shale barrier are proposed. The location of the shale barrier is placed above the steam injection well, and the top injection well is set above the shale barrier. For an improved case, once the steam chamber front reaches the horizontal edge of the shale barrier, the top injection well can be activated as a steam injection well to replace the previous steam injection well in the SAGD well pair. From the experimental observation, the effect of the top injection well is evaluated. Subsequently, a set of numerical simulation runs are performed to match the experimental measurements. Therefore, from this laboratory-scale simulation model, the effect of shale barrier size is discussed, and the switch time of the top injection well is also optimized to maximize the recovery process. Experimental results indicate that a top injection well-based oil drainage mode can effectively unlock the heavy crude oil above shale barrier and improve the entire SAGD production. Compared with a basic SAGD case, the top injection well can increase the final oil recovery factor by about 8%. Simultaneously, through a mass conservation law, it is calculated that the unlocking angle of remaining oil reserve above the shale barrier is about 6°. The angle can be used to effectively evaluate the recoverable oil reserve after the SAGD process for the heavy oil reservoir with a shale barrier. The simulation results of our laboratory-scale numerical simulation model are in good agreement with the experimental observation. The optimized switch time of the top injection well is the end of the second lateral expansion stage. This paper proposes a new oil drainage mode that can effectively reduce the shale barrier effect on SAGD production and thus improve the recovery performance of heavy oil reservoirs.

Effects of different steam injection conditions on cappuccino's nutritional profile.

The quality parameters of cappuccinos prepared with pasteurized milk or ultra-high-temperature milk steam-injected at different temperatures by a professional coffee machine have been assessed. In particular, the protein profile, the content of vitamins and lactose, the lipid peroxidation process, and the involvement of milk proteins in the foam formation were evaluated. The nutritional quality of milk seems not affected by the steam injection treatment carried out at a temperature of 60-65°C, but at higher temperatures a decrement of lactoperoxidase, vitamin B6 and folic acid was observed. The milk used in cappuccino preparation is very important: pasteurized milk can form a more consistent and lasting foam with respect to ultra-high-temperature milk because of the presence of β-lactoglobulin and lactoferrin, both playing an important role in the foam formation and stability. This work would provide additional information to the coffee industry for the preparation of high nutritional and organoleptic quality cappuccinos.

Problem of Injection of Dry Steam into a Reservoir without Condensation in the Well

Problem of Injection of Dry Steam into a Reservoir without Condensation in the Well

Reservoir Simulation of Cross CAGD (XCAGD) Thermal Enhanced Heavy Oil Recovery using Foam with Steam Injection

Among the most important thermal oil recovery enhancement methods, it is possible to point out In-Situ Combustion (ISC) and Steam Assisted Gravity Drainage (SAGD) processes. The “Combustion Assisted Gravity Drainage (CAGD) process” as an oil recovery enhancement method is a specific combination of two methods: 1-In-Situ Combustion process mostly in terms of the process mechanism and the combustion reactions and also the injected gas type. and 2-Steam Assisted Gravity Drainage process mostly in terms of well configuration. Cross CAGD (XCAGD) is akin to CAGD except that the horizontal injectors are placed perpendicular to the horizontal production wells. By combining both gravity drainage and lateral displacement, XCAGD is able to hasten recovery, diminish steam requirements and promote economic potential compared to CAGD. XCAGD is better suited for several near producers with several perpendicular injectors to achieve a better development. It should be noted that near above kick off point of the vertical injectors with the horizontal producers in XCAGD, slotted liner embedding is pivotal. In this paper, a reservoir simulation of Cross CAGD (XCAGD) thermal enhanced heavy oil recovery using Foam with Steam injection has been precisely scrutinized and studied then some good results have been obtained. These good results encompass more recovery factor of produced oil about %3-5 derived from FOIP curves.

Improvement of syngas quality from two-stage downdraft wood gasification through steam and oxygen injection

The transition from fossil fuels to clean energy sources requires the supply of gaseous fuels from renewable origin for a number of applications. Such applications include in particular high-temperature heat for industries, and Combined Heat and Power (CHP) for flexible, decentralized power production. Gasification of lignocellulosic biomass is a good candidate to this end, converting solid biomass such as wood residues into a more versatile and CO2-neutral gaseous fuel. Today, the use of syngas remains limited due to its relatively low energy density and challenges related to its residual tar content.To improve the quality of syngas on these two aspects, we have studied the injection of steam and oxygen in a pilot two-stage downdraft gasifier. Replacing secondary air by oxygen enhances the Lower Heating Value (LHV) by 65%, while steam injection boosts the H2/CO ratio and damps the temperature rise due to oxygen. The gasification efficiency is enhanced by both oxygen and steam. As a drawback, oxy-steam conditions yield more Class III and IV tars in the syngas. The combined use of oxygen and steam can enhance the volumetric power of syngas-based CHP engines, and provide a sustainable fuel for high-temperature industrial applications.In future research, longer runs should be done to confirm the effects of steam and oxygen on conversion efficiency. The injection of steam and oxygen at the primary stage should also be studied. The presented results will help choosing whether to use oxygen and steam in downdraft gasification applications, and support the validation of numerical models.

Fully coupled thermo-hydro-mechanical model with strain-dependent properties for numerical simulation of heavy oil production

Strain-dependency of permeability is a key feature for coupled multiphysics phenomena during heavy oil production under steam stimulation. This feature is also the basis for accurate estimation of steam needed to properly stimulate a given target heavy oil block. In this study, a fully coupled thermal-hydro-mechanical model is established and applied to the numerical simulation of steam injection in a block of western China Xinjiang region's heavy oil field. Strain-dependent relationships have been established for hydraulic conductivity as well as Young's modulus of reservoir formations. The distribution of reservoir temperature field and pore pressure field is obtained, and a quantitative evaluation of steam injection effectiveness is provided. The principal contents include: 1) A simplified fully coupled thermal-hydro-mechanical model for heavy oil reservoir under steam injection is presented. The model incorporates strain-dependent characteristics for rock's permeability/hydraulic conductivity and elastic modulus. 2) The simplified fully coupled model is implemented via the user subroutines of Abaqus software, and 3D finite element simulations are conducted for the steam stimulation operation and oil production processes in the heavy oil block. The temperature field and pore pressure field of the reservoir are obtained under given production history and steam injection conditions. These numerical results have provided an accurate evaluation of steam injection effectiveness. These numerical results indicate that: 1) The original design of steam injection volume and soak time is insufficient to connect the temperature rise regions around wells A1 and A2 in the block in order to get ideal production rate. The temperature rise data obtained from monitoring wells verify the accuracy of the calculation results, demonstrating the accuracy and practicality of the proposed theoretical model. 2) It is found that the maximum local pore pressure induced by steam injection may exceed the bottomhole pressure of injection wells. This is due to the thermal expansion of both solids and pore fluids caused by rapid temperature rise. 3) For the target reservoir, numerical results indicate that further steam injection for 17 days on top of the original design will connect the temperature rise regions around wells A1 and A2, and the minimum temperature at various points between wells will exceed 40 °C.

New Design Method of a Supersonic Steam Injection Nozzle and Its Numerical Simulation Verification.

Steam huff-n-puff in horizontal wells often had limitations, such as uneven steam injection and low reservoir utilization. To improve steam injection efficiency, a new method for designing a supersonic nozzle was proposed based on the principles of aerodynamics and thermodynamics. The nozzle featured a tapering section, a throat, and a diverging section. The best geometric shape of the tapering section was the Witoszynski curve. A set of nozzle size designs were established, and the size parameters were optimized. The results showed that the nozzle could inject steam into the formation at supersonic speed and it had the characteristics of constant flow rate and uniform development of the steam chamber. According to the steam Reynolds number and the good aggregation distribution characteristics of the size design model, three sequential nozzles of 3.0, 5.0, and 6.5 mm were formed based on the throat. When the throat diameter was 5.0 mm, the tapering length was 4.3 mm, the diverging length was 5.5 mm, the throat length was 3.0 mm, the inlet diameter was 9.8 mm, and the outlet diameter was 6.2 mm. Numerical simulations indicated that the pressure drop loss during steam huff-n-puff injection in horizontal wells was within 10%. It was of great significance to establish the nozzle size design model of the steam injection effect of horizontal wells.

Dynamic insights of carbon management and performance enhancement approaches in biogas-fueled solid oxide fuel cells: A computational exploration

The solid oxide fuel cell (SOFC) is drastically affected by carbon deposition when exposed to hydrocarbon fuels such as biogas. Ensuring sustainable energy production requires long-term operation free from carbon formation. In this study, a transient computational fluid dynamics numerical model was developed to analyze the effects of carbon deposition when utilizing biogas as fuel. In addition to validating the model with experimental results, including polarization and stability curves and gas composition within the cell were also compared for the first time, revealing good agreement. Initially, a comparison was made between biogas and coal gasification fuel gas (CGFG) to study the impact of gas composition. Namely, biogas showed a higher power density than the CGFG but an unstable operation, decreasing the cell voltage by 43% at 750 °C and constant current density of 0.2 A cm−2 over 40 h. Additionally, while the rise in applied current density showed no significant impact on the carbon formation rate, increasing cell temperature and current density amplified the power reduction rate. Moreover, potential approaches for regulating the rate of carbon formation were investigated. Namely, N2 (mole fraction = 50%), CO2 (CO2:CH4 = 2), and steam injection (steam: CH4 = 1) led to a cell voltage decline of 12%, 1%, and 3%, respectively. In addition, an anode thickness growth could improve power generation and enhance the cell operation stability so that cell voltage degradation of 8% resulted in 0.8 mm thickness of the anode.

Numerical simulation of oil shale in-situ exploration productivity comparison between steam injection and electrical heating

Oil shale is an important alternative resource to the conventional oil and gas because of its rich reserves. The in-situ heating exploitation is the most promising method to produce oil from the oil shale, mainly including electrical heating and steam injection heating. However, to the best of our knowledge, a comprehensive comparison between these two kinds of heating methods is still absent, thus the comparison is necessarily conducted to provide suggestions on how to select heating modes for the oil shale in-situ exploitation. On this basis, a systematic comparison is presented between in-situ steam heating and electrical heating, including physical and process parameters, and then sensitivity analysis and optimization on key parameters are carried out. Simulation results show that steam injection heating is superior to electrical heating in output, energy consumption and production cycle. The flow rate and temperature of the injected steam and the specific heat capacity of oil shale are sensitive to productivity. The production will be increased with larger injection flow rate and temperature. The thermal conductivity and porosity are less sensitive to the mining efficiency compared to the injection flow rate and temperature. At the same time, different well pattern structures also have an impact on productivity, and the hexagonal well pattern has better productivity benefits than the triangular and quadrilateral well patterns. In the simulation case of this paper, the most conducive parameters for exploitation were derived as injection flow rate 0.20 kg/s, injection temperature 650 °C, specific heat capacity 1.5 kJ/(kg⋅K), thermal conductivity 0.5 W/(m⋅K), porosity 0.05. These results are expected to provide theoretical suggestions for improving the productivity efficiency of oil shale in-situ exploitation.

Analysis of the influence of the thermophysical parameters of the reservoir and fluid on the process of cyclic steam stimulation

Currently, the existing models of cyclic steam stimulation do not allow to research the development of the heat front at the stage of steam injection into the reservoir, considering the possible influence of both convective and conductive flows, as well as the properties of the rock and fluid. Knowledge of the dynamics of the development of fronts allows to determine the features of the ongoing physical processes at specific deposits and can be used to optimize the production process. The aim of the work is to analyze the development of the thermal field in rocks with different thermophysical parameters. A hydrodynamic model of the development of the thermal field was developed and calculated on the tNavigator software package for rocks with various thermophysical properties. The model considering the three-dimensional propagation of heat, the properties of reservoir and injected fluids, as well as heat loss into the top and the bottom of the reservoir. The comparison of the maximum dimensions of the heated area calculated according to the developed hydrodynamic model with the results obtained by the integral model is carried out. The dependence of the advance of the thermal front on the specific heat capacity and thermal conductivity of the rock is determined. The thermal front moves much further in rocks with a lower specific heat capacity and thermal conductivity with the same injection volume. It is shown that the convective component of heat exchange weakly depends on the specific heat capacity and the shape of the heat front remains the same in all cases.

Preparation and Modification of Biochar and Application of Modified Biochar in Remediation of Contaminated Soil

Biochar, with its unique properties including high specific surface area, has become an increasingly popular material in the field of environmental restoration. The present paper provides a systematic analysis and summary of the preparation, characterization, and modification strategies for traditional biochar, as well as its application in soil remediation. A variety of different methods have been developed and applied to produce biochar, of which the most commonly used method is pyrolysis which consists mainly of slow and fast pyrolysis, followed by hydrothermal carbonization. Biochar can be modified by the injection of acids, alkalis, metal oxides, metal ions, steam and gas. On this basis, the utilization of modified biochar in soil restoration and remediation was further analyzed. Modified biochar breaks through various limitations such as the instability of traditional biochar, and performs an irreplaceable function not only in adsorption of organic pollutants, but also in the removal of heavy metal pollution. Additionally, managers also need to avoid the potential risk of secondary contamination by releasing polycyclic aromatic hydrocarbons (PAHs) into the surrounding environment. The aim of this paper is to explore the basic properties and preparation methods of biochar, to identify its restrictions and different modification methods, to highlight the contribution that modified biochar can make to today's sustainability-focused world, and to lay the groundwork for future research.

Experimental study on flow resistance characteristics of the uniform steam injection outflow control device.

Introduction: Multi-point steam injection technology is a new completion method for heavy oil horizontal wells to solve the uneven distribution of the intake profile in the horizontal section. It is equipped with the flow control device to achieve the effect of balanced steam injection. Methods: The steady-state experiment method was adopted; Considering the variable mass complex flow of the steam-liquid two-phase flow in the downhole flow device, the pressure loss of downhole tools through uniform steam injection with different steam-liquid compositions was tested, the influencing factors of the pressure drop were analyzed, and a more reliable pressure drop calculation method was established. Results: The overflow pressure drop can be adjusted by changing the aperture, steam dryness, and fluid flow of the downhole outflow control device (OCD). Discussion: By comparing the experimental and theoretical results, the calculation method of the overflow resistance of single-phase and steam-liquid two-phase fluids in OCD is given, and the error is within the usable range.

A numerical study on oscillatory characteristics of unstable steam jet in water flow within a vertical pipe

In this study, a numerical investigation was conducted to examine the condensation and pressure oscillation characteristics of low mass flux steam jets in water flow within a vertical pipe under different operating conditions. Three bubble states were observed during the injection of subsonic steam in an upward direction into a subcooled water flow: bubble growth, bubble necking, and bubble detachment. Through a synchronously analysis of the bubble morphology and interface pressure, the oscillation mechanism of the unstable steam jet was revealed. The results showed that the pressure oscillation characteristics were consistent with the behavior of the vapor bubble. The frequency of pressure oscillation increased with the increase of steam inlet pressure and water Reynolds number, while decreased with the decrease of subcooled water temperature. The intensity of pressure oscillation exhibited a distinct peak at the position corresponding to the detachment of the primary and secondary bubbles. Moreover, a new predictive correlation for pressure oscillations in flowing water was presented by the frequency of steam injection, the condensation driving potential, the steam mass flux, the Weber number, and the water Reynolds number. The predicted values showed good agreement with the experimental values, with a maximum deviation of 24 %

Sterilization of yak milk by direct steam injection (DSI) and effects on milk quality

To facilitate development of new yak milk products with high added value, sterilization effects of direct steam injection (DSI) were evaluated. The Z value (temperature increase necessary to reduce inactivation time by 90%) of Geobacillus stearothermophilus spores (ATCC 7953; 106 CFU mL−1) in yak milk was 5.88 °C. Heating of the milk above 153.86 °C for 0.116 s achieved complete inactivation of ATCC 7953 spores; i.e., commercially-acceptable sterility. The native lactoferrin and β-lactoglobulin (β-Lg) contents of the milk decreased by 40 and 30% after DSI treatment, respectively, whereas the α-lactalbumin (α-La) content did not differ significantly; the overall extent of denaturation of heat sensitive proteins was lower than in UHT milk. The furosine and lactulose contents in DSI treated yak milk were ≤1.11 mg/10 g of protein and 0.368 mg/10 mL, respectively, similar to those in pasteurized milk. The pH, Hunter color values and aroma were significantly influenced by DSI treatment, but the overall sensory acceptability of DSI treated yak milk was assessed as good. These findings indicate that DSI has great potential for producing yak milk and processed yak milk products with considerable added value.

THE ENHANCEMENT OF TEMPERATURE IN BOILER BY STEAM INJECTION

The boiler is equipment widely used in various industrial sectors such as power plants, fertilizer plants, paper mills, and others. The combustion chamber is an important part of the boiler which can determine the quality of the steam product. The main problem has happened in combustion chambers such as unburned hydrocarbon/carbon loss which is called fouling. Fouling has occurred in many boilers, which use coal or oil as fuel for the production of steam and decreases boiler performance. The purpose of this research is to increase temperature by adding steam injection to reduce fouling to compare with and without steam injection. Two indicators that have the potential to enhance heat transfer are the elevation in temperature and the reduction in fouling percentage. The variables in this research were air flow of 15 L/min, 17,5 L/min, and 20 L/min and steam injection pressure of 2 bars, 3 bars, and 4 bars. The maximum temperature enhancement was 37,5% in 15 L/min of air flow at a steam injection pressure of 2 bars and 3 bars. The maximum fouling abatement was 78,57% in 15 L/min at a steam injection pressure of 4 bars.

Numerical Simulation Analysis of Wellbore Integrity and Casing Damage in High-Temperature Injection and Production of Shale Oil

Shale oil represents a relatively new form of unconventional oil and gas resource, and the extensive exploration and development of shale oil resources carry significant implications for China’s oil and gas supply and demand dynamics. At present, within the realm of low-maturity shale oil extraction technologies, the reservoir must be subjected to elevated temperatures ranging between 400 to 60 °C. Prolonged exposure of wellbores to such high temperatures can result in a substantial decrease in cement strength, the formation of microcracks due to cement cracking, and damage stemming from thermal stresses on the casing. Casing damage stands out as a prominent factor contributing to wellbore integrity failures and well shutdowns within the context of shale oil development. Given the limited natural energy reservoirs of shale oil formations, it becomes necessary to supplement the reservoir’s energy during the development process. Furthermore, shale oil exhibits high viscosity and poor flowability, and conventional water injection methods yield limited efficacy. This situation can induce significant shifts in the stress field and rock mechanical parameters, potentially activating specific formations and complicating the load dynamics on the casing. Consequently, the risk of failure increases. In light of these considerations, this study uses numerical simulations to study the integrity of high-temperature injection and production wellbores in shale oil and aims to encompass a comprehensive evaluation and analysis of the principal factors that influence casing damage, the fluctuations in thermal stress, and the yield strength of various steel grades of casings exposed to alternating stress conditions. Subsequently, this paper developed a model for simulating the temperature and pressure within shale oil and steam injection wellbores to support engineering design analysis. The research results indicate that the application of pre-stress results in a significant increase in stress at the casing pipe head while causing a noticeable decrease in stress within the pipe wall. When N80 casing is used, the entire casing experiences thermal stresses surpassing the casing’s yield limit. Stress concentration may arise at both ends of the external seal, potentially leading to casing contraction, shear failure, and, under non-uniform stress conditions, casing bending deformation. The temperature of steam injection significantly influences the temperature field of the casing wall, with stress values experiencing a marked reduction when the steam injection temperature decreases from 350 °C to 200 °C, underscoring the substantial impact of temperature on casing thermal stress. As the steam injection process advances along with injection-production cycles, shear stresses at the interface can exceed the bond strength, resulting in relative slippage between the cement and the casing. The bonding force between the wellbore and the cement primarily depends on the interface’s friction, particularly in the context of friction during wellhead lifting. This study endeavors to determine rational injection and production parameters under varying conditions, optimize completion methods, reduce casing damage, and extend the casing’s operational life; it aims to offer critical technical support for the safe and efficient development of shale oil resources.

Foaming properties of milk samples collected at various processing stages in a dairy processing factory across two seasons.

A foam layer makes an essential contribution to the quality of cappuccino-style drinks. Poor foaming of milk occurs quite often, however, especially in summer. The reasons for this are still unknown. Although a substantial number of studies on the foaming process of milk have been reported, these studies have been laboratory based and have used laboratory or pilot-scale equipment to simulate the processing conditions of a dairy processing factory. This study collected about 40 different samples across different processing stages in a dairy factory over two seasons (two batches per season) and investigated their composition and physical and foaming properties by mechanical mixing and steam injection. The results showed that milk samples collected in summer had a significantly higher content of fat, free fatty acids, and Ca2+ ions, and larger particle sizes but a markedly lower concentration of protein and solid non-fat, and surface tension than the samples collected in spring. These differences provided spring milk with a higher steam injection foamability than summer milk. However, steam injection foam stability, and mechanical mixing foamability and foam stability were not affected by seasonal factors. Milk samples collected in different batches within a season were almost identical with regard to the properties that were investigated. The variations in composition and physical properties of milk collected between two seasons could be the reasons for their difference in foamability but not for foam stability. Processes such as standardization, homogenization, and pasteurization improved markedlythe foaming properties of milk. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The foam reinforced with Janus amphiphilic graphene oxide to control steam channeling in heavy oil reservoir

Foams have been considered effective diverters to decrease the mobility in the steam channel for heavy oil-recovery processes. Due to the high weight of chemical additive loss caused by adsorption to the rock surface and the poor thermal stability of these additives, the result of surfactant or polymer is usually unsatisfactory. To avoid these problems, nanoparticles can be utilized as novel assistants to enhance the generation and stabilization of foams. In this research, an amphiphilic graphene oxide (H-GO2), which is very effective at low concentrations, is utilized to enhance the foam performance in the process of plugging steam channeling. Compared with the foam prepared by using surfactant alone, the foam height and half-life at a low concentration (0.05 wt%) of H-GO2 in bulk medium increased by approximately 151% and 341%, respectively. The size distribution of bubbles in the presence of 0.05 wt% H-GO2 is uniform, and H-GO2 creates the gas-liquid interface film three times thicker than that of the surfactant without H-GO2. As NaCl concentration increased from 0.5 to 5 wt%, more foam was generated in a shorter time, and the half-life became longer. Excess NaCl causes less foam formation and a shorter half-life. Foam generation and stabilization are reduced with the CaCl2 concentration in solution increasing from 0 to 10 wt%, or the temperature increasing from 150 to 240 ℃. Corefloods with coinjected CO2 and water containing 0.05 wt% H-GO2 and surfactant can double the resistance factor of foam in the porous medium, compared with coinjection of CO2 and water containing only surfactant. The additional oil recovery of foam generated by surfactant alone is 14.6%. It is extraordinary that the increased recovery of 31.4% can be obtained by introducing only 0.05 wt% H-GO2 into the same foam. This work may provide a reference for steam channeling control in the steam injection development process of heavy oil oilfields.

Biomass gasification: Sub-pilot operation of >600 h with extensive tar cracking property and high purity syngas production at H2:CO ratio ∼2 using moving bed redox looping technology

Commercializing biomass-based technologies as an alternative to fossil fuels is necessary for a sustainable future. This study proposes a robust Biomass to Syngas (BTS) chemical looping system to gasify biomass into syngas for a range of downstream applications, with focus on liquid fuel production. The system has been demonstrated on a sub-pilot scale cumulatively for over 600 h, proving the technology's commercial viability. Pelletized corn cob, woody pellets, and unpelletized loose corn cob, were successfully tested, proving the robusticity of the process to handle untreated biomass with batch variation. Tar analysis shows that moving bed reducer can reduce the tar concentration to 0.5 g/m3, owing to uniform residence time, high temperature, and catalytic activity of oxygen carrier, while injection of steam as an enhancer gas increases carbon conversion by char gasification. A variable syngas quality with an H2/CO ratio of ∼2 and a syngas purity greater >70% was achieved, making this syngas suitable for the generation of liquid fuels via Fischer-Tropsch synthesis. The biomass requirement for a chemical looping system decreases by 13.9% over the conventional biomass gasifier for generating the same amount of liquid fuels. Heat integration suggests integrating biomass drying with the combustor exhaust air for process authothermicity.

Biomass chemical looping: Advancements and strategies with the moving bed reactor for gasification and hydrogen generation

This work presents advances in OSU's BTS technology, targeted explicitly toward hydrogen production from experimental and process simulation results. Two experimental parameters: residence time and enhancer steam flowrate, are explored. A volume reduction of ∼67 % can be achieved in Reducer while ensuring high char conversion. The steam injection enhances char gasification and H2 content; however, it may lead to increased tar content due to decreased gas residence time. The steam injection of ∼5 % of the inlet carbon flow rate can be adequate for efficient biomass gasification and injecting additional steam downstream into the WGS unit is optimal for H2 generation. Two cases that implement modularization for tighter process integration are compared with the conventional BTS and BDCL processes for H2 generation. The application of modularization eliminates the energy-intensive AGR unit and increases ETE by ∼17 % over the BTS process. Modularization offers product flexibility and increased control with lower operational risks over the BDCL process but at 7 % lower ETE, which can be attributed to the high amounts of oxygen present in the biomass, leading to decreased syngas purity. H2 yield can be further increased by co-injection of low oxygen feedstocks such as plastics, which can increase H2 yield by ∼12 %.