Average Reactor Temperature Research Articles

Solar thermal pyrolysis of non-edible seeds to biofuels and their feasibility assessment

The present study is focused on conversion of non-edible Jatropha seeds biomass to biofuels i.e., liquid, solid and gaseous fuels via solar thermochemical pyrolysis process. All the three products namely; (i) bio-oil (liquid) (ii) biochar (solid) and (iii) pyrolytic gas were characterized by means of TG (Thermo-gravimetric), FTIR (Fourier transform infrared), GC–MS (Gas chromatography mass spectroscopy), proximate and ultimate analysis; and assessed their feasibility as fuel candidates. It is explored that 20% maximum bio-oil yield was obtained with the average reactor temperature of 250–320°C. The pyrolytic zone for the biomass was identified in the range of 203–508°C. The ultimate analysis of the bio-oil revealed that the oil is rich in carbon (58.3%) and hydrogen (8.7%) with an average chemical composition of CH1.79N0.05O0.40. Relatively lower oxygen content in the bio-oil favors for high heating value. Higher H/C ratio (1.79) and lower O/C ratio (0.4) of the bio-oil indicates its suitability as petroleum fuel for engine applications. The carbon compounds present in the bio-oil are from C7 to C28 which may represent the mixture of diesel and gasoline fuels. Finally, it is emerged from the study that all the three products are exibiting various favorable conditions to be employed as fuel candidates for different applications such as engines and boilers.

Refuse Derived Fuel (RDF) production and gasification in a pilot plant integrated with an Otto cycle ICE through Aspen plus™ modelling: Thermodynamic and economic viability

This work deals with the development of a Refuse Derived Fuel (RDF) gasification pilot plant using air as a gasification agent. A downdraft fixed bed reactor is integrated with an Otto cycle Internal Combustion Engine (ICE). Modelling was carried out using the Aspen Plus™ software to predict the ideal operational conditions for maximum efficiency. Thermodynamics package used in the simulation comprised the Non-Random Two-Liquid (NRTL) model and the Hayden-O'Connell (HOC) equation of state. As expected, the results indicated that the Equivalence Ratio (ER) has a direct influence over the gasification temperature and the composition of the Raw Produced Gas (RPG), and effects of ER over the Lower Heating Value (LHV) and Cold Gasification Efficiency (CGE) of the RPG are also discussed. A maximum CGE efficiency of 57–60% was reached for ER values between 0.25 and 0.3, also an average reactor temperature values in the range of 680–700°C, with a peak LHV of 5.8MJ/Nm3. RPG was burned in an ICE, reaching an electrical power of 50kWel. The economic assessment of the pilot plant implementation was also performed, showing the project is feasible, with power above 120kWel with an initial investment of approximately US$ 300,000.

Hydrocracking of vacuum residue with solid and dispersed phase catalyst: Modeling of sediment formation and hydrodesulfurization

Effect of dispersed Mo based catalyst on residual hydrocracking was investigated in this paper. The study was performed in an industrial scale hydrocracking unit with the average reactor temperature of 399–419°C and pressure of 18MPa. Vacuum residue from Ural crude oil was fed to the reactor. A sediment formation model was proposed with parameters sets for the regime with classical supported Ni-Mo/Al2O3 catalyst and for that with a combined system of supported and dispersed catalyst. Four process parameters were incorporated in the model equation: reaction temperature, hydrogen partial pressure, exothermic gain and hydrogen makeup to feed mass ratio. A decrease of the sediment formation with the application of dispersed Mo catalyst was observed, which results in higher Mo concentration in the liquid phase and thus in higher hydrogenation activity and stabilization of coke precursors. Hydrodesulfurization was also investigated and a sulfur distribution model was created with parameters for both regimes. The model contains three lumps with significant sulfur content: sulfur contained in the vacuum residue, sulfur contained in the vacuum gas oil and hydrogen sulfide. Application of the catalyst and increase of reaction temperature from 399–414°C to 414–419°C resulted in increase of average sulfur conversion in vacuum residue from 86.5% to 87.9%.

Reactor temperature profiles of non-thermal plasma reactor using fiber Bragg grating sensor

The temperature profile of atmospheric pressure non-thermal plasma packed-bed reactor was monitored using a single 1550nm fiber Bragg Grating (FBG) sensor with sensitivity of 10.8pm/°C. The FBG was embedded at the midpoint of the reactor which was packed with barium titanate (BaTiO3) pellets. Four types of carrier gas for plasma generation were manipulated with different applied voltages for each gas in order to investigate the behaviour of the temperature profiles of non-thermal plasma (NTP). Results showed that using air and nitrogen, plasma produced higher average reactor temperature, which is approximately 207°C and 202°C respectively, in a 30-min interval with the maximum applied voltage of 16kV. The reactor temperature for helium carrier gas revealed the lowest, approximately 77°C. Reactor temperature profiles for each type of gas is different due to the gas composition and breakdown voltage behaviour. From the reactor temperature profiles, we were able to examine the appropriate carrier gases and optimum applied voltage operating range in order to enhance plasma process for treating pollutants in future work since higher temperature affect the rate of chemical reaction.

Effects of geometry and operating conditions on hydrogen productivity of a fuel cell reformer

A 250-kW fuel cell reformer was numerically simulated with a user-defined function that was designed to simultaneously model reforming and combustion reactions. The calculation domain was a simplified 3-D configuration. To investigate the effects of geometry and operating conditions on the hydrogen productivity, the combustor outlet position, fuel ratio, equivalence ratio, and steam to carbon ratio were variable parameters. The numerical results show that the flow distributions in the furnace vary with respect to the combustor outlet position. The varied flow results in temperature distributions, which predicts the nonuniform hydrogen productivity in each reactor. Measuring the temperatures at reactor centers is an effective method for predicting the hydrogen productivity because the overall reforming reaction is affected by the average reactor temperature, which can be estimated by the temperature at the reactor center. The overall results for varying the operating conditions were summarized as a table by some nondimensional variables. By referring to the table, the proper operating conditions in similar reformer systems can be determined faster and more simply than by performing a conventional experiment.

Catalytic autothermal reforming of methane: Performance of a kW scale reformer using pure oxygen as oxidant

Abstract The autothermal low temperature catalytic partial oxidation of methane was investigated in a bench-scale reactor (1 kWth power) over a structured ruthenium catalyst (metal monolith support). Pure oxygen was used as the oxidant. Autothermal operation of the reactor was successfully demonstrated. The increase of the O/C ratio increased the average reactor temperature resulting in higher methane conversions. Similar results were obtained for the increase of the space velocity. The product gas generated was rich in hydrogen (65%), nitrogen-free and contained comparably low amounts of carbon monoxide (5%). The results revealed that the oxygen-blown reforming at low temperatures could be a well-suited process for the production of hydrogen in conjunction with a carbon dioxide sequestration.

Inactivation of Botrytis cinerea During Thermophilic Composting of Greenhouse Tomato Plant Residues

The effectiveness of in-vessel thermophilic composting on the inactivation of Botrytis cinerea was evaluated. The bioreactor operated on an infected mixture of tomato plant residues, wood shavings, and municipal solid compost (1:1.5:0.28). Tap water and urea were added to adjust the moisture content and C:N ratio to 60% and 30:1, respectively. Used cooking oil was added as a bioavailable carbon source to compensate for heat losses from the system and extend the thermophilic composting stage. The controlled thermophilic composting process was successful in inactivating B. cinerea. During all experiments, the average reactor temperature increased gradually, reaching its peak after 31 h of operation. Temperatures in the range of 62.6-63.9 degrees C were maintained during the thermophilic stage by the intermittent addition of used cooking oil. The results of the enzyme-linked immunosorbent assay test indicated that the initial concentration of B. cinerea in the compost samples (14.6 mug of dried mycelium/g of compost) was reduced to 12.9, 8.8, and 2.4 mu/g after 24, 48, and 72 h of thermophilic composting, respectively. Plating assay indicated that the mold was completely inactivated in samples after 48 h of thermophilic composting. No significant reduction in B. cinerea was observed during the transient phase (first 30 h of rising temperature) because the temperature reached the lethal level of 55 degrees C after 23 h, thus allowing only 7 h of exposure to temperatures higher than 55 degrees C during this phase. The relatively short time required for complete inactivation of B. cinerea was achieved by maintaining a constant high temperature and a uniform distribution of temperature and extending the duration of the thermophilic stage by the addition of the proper amount of bioavailable carbon (used cooking oil).

An improved weighted average reactor temperature estimation for simulation of adiabatic industrial hydrotreaters

A study on the improvement of the representative operating temperature from the temperature profile of an industrial adiabatic reactor is presented. This temperature is used to simulate the reactor performance by small scale laboratory isothermal reactors. An improved methodology for the estimation of a Weighted Average Bed Temperature (WABT) was elaborated to simulate an industrial multi-bed HDS reactor. The improved WABT, so called Weighted Average Reactor Temperature (WART), was compared with the most usually used WABT in a wide range of operational conditions as well as of kinetic parameters. In case of a multi-bed industrial hydrotreater, where quench zones are located between the beds and the H 2 flow rate, which enters each bed, is different, the optimal gas to oil ratio was estimated for the laboratory-scale reactor.

Reduction of taconite concentrates in a cyclone reactor

A cyclone reactor system for the partial reduction and melting of taconite concentrate fines was designed and operated. A nontransferred arc plasma torch was employed as a heat source. Taconite fines, carbon monoxide and carbon dioxide were fed axially into the reactor, while the plasma gas was introduced tangentially into the cyclone. The average reactor temperature was maintained above 1673°K (1400°C), and reduction experiments were performed under various conditions. The influence of the following parameters on the reduction of taconite was investigated: carbon monoxide to carbon dioxide inlet feed ratio, carbon monoxide inlet partial pressure and average reactor temperature. The interaction of the graphite lining with carbon dioxide and taconite were also studied.

Liquefaction of coal by SRC‐II process: Part IV: Steady‐state thermal behavior of the reactor

AbstractAn axial dispersion thermal model of an SRC‐II reactor is developed. The model is validated by simulation of steady‐state temperature profiles in the Fort Lewis (Tacoma, Washington) pilot‐plant SRC‐II reactor. The simulation shows that normal operations of the SRC‐II reactors are thermally unstable. Changes in the process conditions can be utilized to achieve thermal stability for the reactor at normal SRC‐II operating temperatures, i.e., reactor outlet temperature of less than 465°C and average reactor temperature of about 455°C. However, thermal stability of the reactor would always result in reduction in the rate of reaction. Regions of unstable steady‐state reactor temperature over large ranges of ash concentrations in the reactor and reactor feed temperatures are also illustrated.