scholarly journals Kinetic Modeling Study of the Industrial Sulfur Recovery Process for Operating Condition Optimization

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shan Huang ◽  
Zhaohui Teng ◽  
Lisheng Zhang ◽  
Qulan Zhou ◽  
Na Li
Keyword(s):  
Recovery Process ◽  
Thermal Reactor ◽  
Recovery Efficiency ◽  
Sulfur Recovery ◽  
Analysis Model ◽  
Detailed Mechanism ◽  
Excess Air ◽  
Excess Air Coefficient ◽  
Reactor Temperature ◽  
Reactor Network

Sulfur recovery from acid gas (H2S and CO2), which is contained in fresh natural gas, can bring many economic and environmental benefits, and this topic has been studied for years. Finding an optimal operating condition for the factory is of much importance. In this paper, we built a reactor network analysis model with a detailed mechanism to describe and calculate the process in the sulfur recovery unit. This detailed mechanism included 94 species and 615 elementary reactions. Our model has a more accurate residence time than other existing models. This simulation model was verified with industrial data, and the calculation result was highly consistent with the industrial data and more accurate than other approaches. Then, we used this reactor network analysis model to study the effect of the excess air coefficient, the thermal reactor temperature, and the temperature of cooling water on the sulfur recovery efficiency of a real device in the Puguang gas field. The result showed the excess air coefficient and thermal reactor temperature had a clear impact on sulfur recovery efficiency. After analysis, we got the optimum condition parameters for this device. At last, these parameters were tested in the real sulfur recovery device, and the result was reasonable. Our research provides a way to improve the sulfur recovery process in the industry, and it can be helpful to reduce pollution emissions and improve economic performance.

Role of Toluene and Carbon Dioxide on Sulfur Recovery Efficiency in Claus Process

2014 ◽  
Author(s):  
Salisu Ibrahim ◽  
Marie Chardonneau ◽  
Ahmed S. AlShoaibi ◽  
Ashwani K. Gupta
Keyword(s):  
Carbon Dioxide ◽  
Operating Temperature ◽  
Optimum Operating ◽  
Recovery Efficiency ◽  
Sulfur Recovery ◽  
Optimum Operating Temperature ◽  
Claus Process ◽  
Acid Gas ◽  
Reactor Temperature

Examination of the effect of toluene and carbon dioxide accompanying acid gases (mainly H2S) in the sulfur recovery process is very critical to determine the optimum operating temperature for enhanced sulfur recovery. Experimental and simulation were used to quantify the conversion efficiency with the addition of different amounts of toluene and carbon dioxide/toluene mixtures to the H2S gas stream. The results showed similar trends between predictions and experimental data, which revealed a decrease in conversion efficiency with increase in toluene or carbon dioxide/toluene addition to the H2S gas stream in a reactor. Further simulations were carried out to seek for the effect of toluene and CO2 addition to acid gas stream on the more favorable operating temperature of the reactor. The results showed that toluene increases the optimum reactor temperature at which enhanced sulfur recovery occurs, whereas it reduces the optimum operating temperature in the presence of CO2. The presence of toluene and CO2 in the acid gas stream affects the sulfur recovery efficiency by altering the optimum temperature of the reactor. These results reveal the importance of reactor temperature and its excursion on sulfur recovery in a Claus process. The effect of mean reactor temperature and its role on detailed chemical speciation from within the reactor as well as the role of key species formed in the process on sulfur recovery are presented.

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

Effect of thermal input, excess air coefficient and combustion mode on natural gas MILD combustion in industrial-scale furnace

Fuel ◽  
2021 ◽  
Vol 302 ◽  
pp. 121179
Author(s):  
Mingming Huang ◽  
Ruichuan Li ◽  
Jikang Xu ◽  
Shen Cheng ◽  
Haoxin Deng ◽  
...  
Keyword(s):  
Natural Gas ◽  
Industrial Scale ◽  
Combustion Mode ◽  
Mild Combustion ◽  
Excess Air ◽  
Excess Air Coefficient

THE EFFECTS OF INLET AIR QUANTITY AND INLET OXYGEN MOLE FRACTION ON THE COMBUSTION AND FLUID FLOW IN A SULFUR RECOVERY UNIT THERMAL REACTOR

2017 ◽  
Vol 41 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Chun-Lang Yeh
Keyword(s):  
Fluid Flow ◽  
High Temperature ◽  
Mole Fraction ◽  
Thermal Reactor ◽  
Sulfur Recovery ◽  
Economical Method ◽  
Sulfur Recovery Unit ◽  
Recovery Unit ◽  
Field Temperature ◽  
High Temperature Operation

Owing to the high temperature inside a sulfur recovery unit (SRU) thermal reactor, detailed experimental measurements are difficult. In the author’s previous studies, several methods have been assessed to resolve the abnormality of the SRU thermal reactor under high temperature operation. This paper presents a new easier and more economical method. The effects of inlet air quantity and inlet O2 mole fraction on the combustion and fluid flow in a SRU thermal reactor are investigated numerically. The flow field temperature, S2 recovery, H2S mole fraction, and SO2 emissions are analyzed. This paper provides a guideline for adjusting the inlet air quantity and the inlet O2 mole fraction to reduce the high temperature inside a thermal reactor and to ensure an acceptable sulfur recovery.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

Numerically Study on Combustion and NOx Emission Characteristics in Tangentially Fired Boiler Co-Firing Semi-Coke

2018 ◽  
Author(s):  
Yongbo Du ◽  
Chang'an Wang ◽  
Pengqian Wang ◽  
Qiang Lv ◽  
Defu Che
Keyword(s):  
Bituminous Coal ◽  
Combustion Efficiency ◽  
Low Rank ◽  
Operation Performance ◽  
Combustion Heat ◽  
Practical Utilization ◽  
Excess Air ◽  
Utility Boilers ◽  
Excess Air Coefficient ◽  
Char Burnout

Semi-coke is a specific solid fuel, which is mainly produced by upgrading low-rank coal. The poor reactivity of semi-coke makes a difficulty to its practical utilization in utility boilers. Previous research was mainly focused on the combustion behavior of semi-coke, while the industrial application has to be understood. In this paper, the effect of co-firing semi-coke and bituminous coal on the operation performance of pulverized boiler was numerically studied. The work was conducted on a 300 MW tangentially fired boiler, and the temperature distribution, the char burnout and NOx production were mainly examined. The results indicate that the incomplete combustion heat loss drops with the increase in semi-coke blending ratio. The NOx concentration increases from 186 mg/Nm3 for only firing the bituminous coal to 200, 214, and 255 mg/Nm3, when the blending ratio was 17%, 33% and 50%, respectively. With enhancing excess air coefficient for the co-firing condition, the combustion efficiency got improved, while NOx production increased very slightly. In general, the boiler is well adapted to co-firing semi-coke, and the semi-coke blending ratio of 1/3 with an excess air coefficient of 1.235 is recommended.

Numerical Simulation on Moisture Influence to MSW Combustion

2014 ◽  
Vol 1006-1007 ◽  
pp. 181-184
Author(s):  
Zhu Sen Yang ◽  
Xing Hua Liu ◽  
Shu Chen
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Flue Gas ◽  
Combustion Process ◽  
Average Temperature ◽  
Excess Air ◽  
Heat Value ◽  
Moisture Influence ◽  
Excess Air Coefficient ◽  
Combustible Gases

The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

Detection of varied defects in diverse fabric images via modified RPCA with noise term and defect prior

2016 ◽  
Vol 28 (4) ◽  
pp. 516-529 ◽  
Author(s):  
Junjie Cao ◽  
Nannan Wang ◽  
Jie Zhang ◽  
Zhijie Wen ◽  
Bo Li ◽  
...  
Keyword(s):  
Principal Component ◽  
Recovery Process ◽  
Low Rank ◽  
Analysis Model ◽  
Content Type ◽  
Robust Detection ◽  
Matrix Recovery ◽  
Noise Term ◽  
The Matrix ◽  
Rank Defect

Purpose – The purpose of this paper is to present a novel method for fabric defect detection. Design/methodology/approach – The method based on joint low-rank and spare matrix recovery, since patterned fabric is manufactured by a set of predefined symmetry rules, and it can be seen as the superposition of sparse defective regions and low-rank defect-free regions. A robust principal component analysis model with a noise term is designed to handle fabric images with diverse patterns robustly. The authors also estimate a defect prior and use it to guide the matrix recovery process for accurate extraction of various fabric defects. Findings – Experiments on plain and twill, dot-, box- and star-patterned fabric images with various defects demonstrate that the method is more efficient and robust than previous methods. Originality/value – The authors present a RPCA-based model for fabric defects detection, and show how to incorporate defect prior to improve the detection results. The authors also show that more robust detection and less running time can be obtained by introducing a noise term into the model.

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