scholarly journals Numerical simulation of UCG process with the aim of increasing calorific value of syngas

2019 ◽  
Vol 7 (1) ◽  
pp. 196-207
Author(s):  
Amin Jowkar ◽  
Farhang Sereshki ◽  
Mehdi Najafi
Keyword(s):  
Coal Gasification ◽  
Operating Time ◽  
Operation Time ◽  
Calorific Value ◽  
Steam Injection ◽  
Injection Rate ◽  
Simultaneous Increase ◽  
Cavity Pressure ◽  
Oxygen Injection ◽  
Positive Effects

AbstractThe determination of operational parameters in the underground coal gasification (UCG) process should be considered in two aspects: first, the total coal in each UCG panel must be gasified and second, the calorific value of the produced gas should be acceptable. The main aim of this study is to present a model that meets these aspects and increasing the calorific value of syngas during this process. In order to achieve those aims, eight different increasing scenarios were devised for total gasification of coal per panel. These scenarios included: increasing oxygen injection rate (scenario 1), the amount of steam injection (scenario 2), operation time (scenario 3), cavity pressure (scenario 4), increase operation time and cavity pressure simultaneously (scenario 5), increase steam injection speed and oxygen injection rate simultaneously (scenario 6), increase in cavity pressure, operating time, steam injection rate and oxygen injection rate simultaneously (scenario 7) and also simultaneous increase in the operating time and steam injection rate (scenario 8). The results showed that for producing syngas with a higher calorific value, the following parameters had the most positive effects respectively: operation time, cavity pressure, steam injection rate and oxygen injection rate. Finally, the model validation was performed for the Centralia LBK-1 UCG pilot and the results showed that this model is very close to reality.

scholarly journals Experimental Study of Reverse Underground Coal Gasification

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2949 ◽  
Author(s):  
Hongtao Liu ◽  
Feng Chen ◽  
Yuanyuan Wang ◽  
Gang Liu ◽  
Hong Yao ◽  
...  
Keyword(s):  
Growth Rate ◽  
Flame Front ◽  
Oxygen Concentration ◽  
Coal Gasification ◽  
Calorific Value ◽  
Injection Rate ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Combustible Gases ◽  
Different Characteristics

Underground coal gasification (UCG) produces less pollution and is safer than traditional coal mining. In order to investigate the effects of different gasifying agents or comprehensive analyses of the characteristics of the gas components in the three zones for the reverse underground coal gasification process, a model test was carried out. The results showed that the oxygen concentration of a gasifying agent is recommended to be higher than 21%, which will lead to more combustible gases and a higher calorific value of gas. Higher flow rates and oxygen content generally afforded more desirable gas compositions and calorific values, with the latter as high as 1430.19 kcal/Nm3. For the enriched oxygen gasifying agent in the reverse gasification process, the flow increase from 10 to 20 Nm3/h affords a rapid increase in the growth rate of the flame front, from 1.80 to 4.88 m/day, which is much faster than that for the air gasifying agent. Increasing the gas injection rate and oxygen concentration will increase the growth rate of the flame front. This affects the distribution of the three zones and further leads to different characteristics of the gas components.

EFFECT OF OPERATING TIME OF THE WELLS IN THE STEADY DRAINAGE MODE BEFORE STOPPING ON THE RESULTS OF THE STUDY OF PRESSURE BUILD-UP CURVES

2017 ◽  
pp. 48-50
Author(s):  
E. F. Gilfanov
Keyword(s):  
Operating Time ◽  
Previous History ◽  
Operation Time ◽  
Pressure Recovery ◽  
Recovery Curve ◽  
History Of ◽  
Accuracy Of Results ◽  
Theoretical Pressure

Operation time of the well before stopping for investigating the pressure recovery curve in hydrodynamic studies is an important parameter affecting the quality and accuracy of results of research processing. Comparing the actual and theoretical pressure curves and the derivative, it’s possible to eliminate the uncertainty in the choice of previous history of the well operation.

L'uretere retrocavale: Embriogenesi e correzione laparoscopica con accesso retroperitoneale in un caso ad ansa bassa

1997 ◽  
Vol 64 (1_suppl) ◽  
pp. 18-22
Author(s):  
C. Trombetta ◽  
G. Savoca ◽  
G. Liguori ◽  
M. Raber ◽  
A. Lissiani ◽  
...  
Keyword(s):  
Operating Time ◽  
Oral Intake ◽  
Operation Time ◽  
Ureteral Stent ◽  
Surgical Wound ◽  
Extraperitoneal Approach ◽  
Intravenous Urogram ◽  
Minimal Morbidity ◽  
Urologic Surgery ◽  
Laparoscopic Techniques

With the minimal morbidity attained using laparoscopy, its application in urologic surgery has been increasing. Using laparoscopic techniques we successfully completed the transposition and re-anastomosis of a retrocaval right ureter. Operation time was 240 minutes. The patient was allowed to walk on the first post-operative day and resumed oral intake on the second day. Administration of analgesics was not required. The ureteral stent was removed on the 24th day after operation. An intravenous urogram three months after operation showed a decrease in hydronephrosis. Laparoscopic correction of retrocaval ureter by extraperitoneal approach is a safe, feasible technique, avoiding a large surgical wound with the definite advantage of minimal disfigurement. Operating time is considerably shorter compared to the peritoneal approach as described by Baba (240’ vs 560’).

scholarly journals Ruhrchemie/Ruhrkohle’s Technical Version of the Texaco Coal Gasifier as Part of a Combined Cycle Plant

1982 ◽  
Author(s):  
B. Cornils ◽  
J. Hibbel ◽  
P. Ruprecht ◽  
R. Dürrfeld ◽  
J. Langhoff
Keyword(s):  
High Pressure ◽  
Power Plants ◽  
Coal Gasification ◽  
Operating Time ◽  
Combined Cycle ◽  
Gas Generation ◽  
Load Following ◽  
Gasification Process ◽  
Steady State Operation ◽  
Combined Cycle Plant

The Ruhrchemie/Ruhrkohle variant of the Texaco Coal Gasification Process (TCGP) has been on stream since 1978. As the first demonstration plant of the “second generation” it has confirmed the advantages of the simultaneous gasification of coal: at higher temperatures; under elevated pressures; using finely divided coal; feeding the coal as a slurry in water. The operating time so far totals 9000 hrs. More than 50,000 tons of coal have been converted to syn gas with a typical composition of 55 percent CO, 33 percent H2, 11 percent CO2 and 0.01 percent of methane. The advantages of the process — low environmental impact, additional high pressure steam production, gas generation at high pressure levels, steady state operation, relatively low investment costs, rapid and reliable turn-down and load-following characteristics — make such entrained-bed coal gasification processes highly suitable for power generation, especially as the first step of combined cycle power plants.

scholarly journals Simulation of performance and nitrogen oxide formation of a hydrogen-enriched diesel engine with the steam injection method

2015 ◽  
Vol 19 (6) ◽  
pp. 1985-1994 ◽  
Author(s):  
Guven Gonca ◽  
Bahri Sahin
Keyword(s):  
Diesel Engine ◽  
Engine Performance ◽  
Steam Injection ◽  
Combustion Model ◽  
Enrichment Method ◽  
Injection Method ◽  
Positive Effects ◽  
Effective Efficiency ◽  
Hydrogen Enrichment ◽  
No Emissions

In the present study, steam injection method (SIM) is implemented to a hydrogen-enriched diesel engine in order to improve the levels of performance and NO emissions. As hydrogen enrichment method increases effective efficiency, NO emissions could be increased. However, the SIM is used to control NO emissions and improve the engine performance. Due to these positive effects, hydrogen enrichment and the SIM)are applied into a diesel engine by using a two-zone combustion model for30% hydrogen enrichment of the fuel volume and 20% steam ratio of the fuel mass at full load conditions. The results obtained are compared with conventional diesel engine (D), steam injected diesel engine (D+S20), hydrogen-enriched diesel engine (D+H30) and hydrogen-enriched diesel engine with steam injection (D+H30+S20) in terms of performance and NO emissions. In the results, the effective efficiency and effective power improve up to 22.8% and %3.1, as NO emissions decrease up to 22.1%. Hence, the hydrogen enrichment with steam injection method is more environmentally friendly with better performance.

Studies on Increasing Specific Calorific Value of Producer Gas in Auto-gasification of Wooden Pallets by Steam Injection

2019 ◽  
pp. 59-70
Author(s):  
G. Prabakaran ◽  
S. Mathiyazhagan ◽  
C. V. Dinesh Kumar ◽  
N. Gunaseelan ◽  
V. Kirubakaran
Keyword(s):  
Calorific Value ◽  
Steam Injection ◽  
Producer Gas

scholarly journals A Multilayer Genetic Algorithm for Automated Guided Vehicles and Dual Automated Yard Cranes Coordinated Scheduling

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qianru Zhao ◽  
Shouwen Ji ◽  
Wenpeng Zhao ◽  
Xinling De
Keyword(s):  
Genetic Algorithm ◽  
Energy Consumption ◽  
Operating Time ◽  
Operation Time ◽  
Complex Model ◽  
Automated Guided Vehicles ◽  
Total Energy Consumption ◽  
Equipment Operation ◽  
Storage Location ◽  
Calculation Results

At present, a lot of studies on automatic terminal scheduling are aimed at the shortest operating time. An effective way to reduce the operating time is to increase the amount of operating equipment. However, people often ignore the additional costs and energy consumption caused by increasing the amount of equipment. This paper comprehensively considers the two aspects of the equipment operation time and equipment quantity matching. With the minimum total energy consumption of the operating equipment as the objective function, a cooperative scheduling model of Automated Guided Vehicles (AGVs) and dual Automated Yard Cranes (AYCs) is established. In the modelling process, we also considered the interference problem between dual Automated Yard Cranes (AYCs). In order to solve this complex model, this paper designs an improved multilayer genetic algorithm. Finally, the calculation results from CPLEX and a multilayer genetic algorithm are compared, and the effectiveness of the model and algorithm is proved by experiments. In addition, at the same time, it is proved that it is necessary to consider the interference problem of dual Automated Yard Cranes (AYCs), and the optimal quantity matching scheme for the equipment and the optimal temporary storage location is given.

scholarly journals A steam rising model of steam-assisted gravity drainage production for heavy oil reservoirs

2019 ◽  
Vol 38 (4) ◽  
pp. 801-818
Author(s):  
Ren-Shi Nie ◽  
Yi-Min Wang ◽  
Yi-Li Kang ◽  
Yong-Lu Jia
Keyword(s):  
Production Rate ◽  
Horizontal Well ◽  
Oil Production ◽  
Steam Injection ◽  
Injection Rate ◽  
Gravity Drainage ◽  
Model Parameters ◽  
Steam Quality ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

The steam chamber rising process is an essential feature of steam-assisted gravity drainage. The development of a steam chamber and its production capabilities have been the focus of various studies. In this paper, a new analytical model is proposed that mimics the steam chamber development and predicts the oil production rate during the steam chamber rising stage. The steam chamber was assumed to have a circular geometry relative to a plane. The model includes determining the relation between the steam chamber development and the production capability. The daily oil production, steam oil ratio, and rising height of the steam chamber curves influenced by different model parameters were drawn. In addition, the curve sensitivities to different model parameters were thoroughly considered. The findings are as follows: The daily oil production increases with the steam injection rate, the steam quality, and the degree of utilization of a horizontal well. In addition, the steam oil ratio decreases with the steam quality and the degree of utilization of a horizontal well. Finally, the rising height of the steam chamber increases with the steam injection rate and steam quality, but decreases with the horizontal well length. The steam chamber rising rate, the location of the steam chamber interface, the rising time, and the daily oil production at a certain steam injection rate were also predicted. An example application showed that the proposed model is able to predict the oil production rate and describe the steam chamber development during the steam chamber rising stage.

Experimental Investigations of Lean Stability Limits of a Prototype Syngas Burner for Low Calorific Value Gases

2011 ◽  
Author(s):  
Ivan R. Sigfrid ◽  
Ronald Whiddon ◽  
Marcus Alde´n ◽  
Jens Klingmann
Keyword(s):  
Equivalence Ratio ◽  
Coal Gasification ◽  
Stability Limit ◽  
Calorific Value ◽  
Kinetic Mechanism ◽  
Experimental Investigations ◽  
Stirred Reactor ◽  
Wobbe Index ◽  
The Stability ◽  
Experimental Values

The lean stability limit of a prototype syngas burner is investigated. The burner is a three sector system, consisting of a separate igniter, stabilizer and Main burner. The ignition sector, Rich-Pilot-Lean (RPL), can be operated with both rich or lean equivalence values, and serves to ignite the Pilot sector which stabilizes the Main combustion sector. The RPL and Main sectors are fully premixed, while the Pilot sector is partially premixed. The complexity of this burner design, especially the ability to vary equivalence ratios in all three sectors, allows for the burner to be adapted to various gases and achieve optimal combustion. The gases examined are methane and a high H2 model syngas (10% CH4, 22.5% CO, 67.5% H2). Both gases are combusted at their original compositions and the syngas was also diluted with N2 to a low calorific value fuel with a Wobbe index of 15 MJ/m3. The syngas is a typical product of gasification of biomass or coal. Gasification of biomass can be considered to be CO2 neutral. The lean stability limit is localized by lowering the equivalence ratio from stable combustion until the limit is reached. To get a comparable blowout definition the CO emissions is measured using a non-dispersive infrared sensor analyzer. The stability limit is defined when the measured CO emissions exceed 200 ppm. The stability limit is measured for the 3 gas mixtures at atmospheric pressure. The RPL equivalence ratio is varied to investigate how this affected the lean blowout limit. A small decrease in stability limit can be observed when increasing the RPL equivalence ratio. The experimental values are compared with values from a perfectly stirred reactor modeled (PSR), under burner conditions, using the GRI 3.0 kinetic mechanism for methane and the San Diego mechanism for the syngas fuels.

Rainwater propeller pumps structural integrity

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sergiu Valentin Galatanu ◽  
Sebastian Muntean ◽  
Liviu Marsavina ◽  
Iulian Ionut Ailinei ◽  
Dan Micota
Keyword(s):  
Shear Stress ◽  
Structural Integrity ◽  
Maximum Shear Stress ◽  
Operating Time ◽  
Operation Time ◽  
Technical Solution ◽  
Catastrophic Events ◽  
Impeller Blade ◽  
Content Type ◽  
Technical Solutions

Purpose The purpose of this paper is to focus on the structural integrity of the rainwater propeller pumps installed in the municipal wastewater treatment plant (WTP). Design/methodology/approach A numerical analysis is performed to determine the maximum shear stress on the fasten bolts. The rainwater propeller pump is examined in operation at normal conditions and when one blade is progressively blocked. Findings The failure mechanism of the rainwater pump impeller is determined. Research limitations/implications The fibbers and wastes are discharged together with rainwater during storms with these types of pumps to avoid the flood of the WTP. Several catastrophic events have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The clogging process is partially understood so actual technical solutions deal with effects rather the main causes. Practical implications The operation time of all seven rainwater pumps installed in Timisoara’s WTP is investigated. Climate changes in Banat region and new waste properties found in the wastewater require appropriate technical solutions. A technical solution is proposed based on these investigations to extend the operation time and to diminish the operation and maintenance costs. Social implications These large pumps are installed in the urban sewage centralised system implemented in the most cities. The access to the sewerage network is a requirement of any community, regardless of the social status. Originality/value The fracture surfaces of both fastening bolts of the rainwater pump impellers produced in service are examined. As a result, it has been identified that the catastrophic events are due to the brittle fracture of both fasten bolts between the impeller blades and the pump hub, respectively. The catastrophic events of the rainwater propeller pumps are directly correlated to the clog level of the impeller. The numerical simulation is performed to determine the maximum shear stress on the fasten bolts. The case with pump operating at normal conditions is performed identifying its vulnerabilities to clog conditions. Next, one impeller blade is progressively blocked considering three time stop scenarios associated with different clog levels. Conclusively, the operating time of the rainwater pump up to the catastrophic failure is correlated to the clog level of the impeller.

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