Operational Performance and Optimization of a 465t/h CFB Boiler in China

2005 ◽  
Author(s):  
Xinmu Zhao ◽  
Junfu Lu ◽  
Jianhua Yang ◽  
Qingguo Zhang ◽  
Fengliang Dong ◽  
...  
Keyword(s):  
Circulating Fluidized Bed ◽  
Bottom Ash ◽  
Heating Surface ◽  
Gas Temperature ◽  
Fuel Gas ◽  
Future Design ◽  
Bed Temperature ◽  
The Future ◽  
And Performance ◽  
Bed Material

In the last three years in China, more than 80 units of 135MWe circulating fluidized bed (CFB) boilers were ordered, and about two dozens of them have been put into operation. So far, the experience and performance evaluation of the boilers with such large capacity are very limited. A series of cold and hot tests were carried out on the boiler in order to optimize the operation and provide more information to the future design. The influence of coal properties, bed material fluidization, air distribution, bed temperature and pressure drop on the boiler performance such as carbon content in fly ash was assessed and discussed. Some problems of the boiler, including the bottom ash system, milling system, abrasion of the heating surface in the furnace, refractory stability, and exhaust fuel gas temperature are reported and suggestions are given for the future improvement and design.

Study on Combustion Adjustment Characteristics of 50MW CFB Biomass-Fired Boiler in Zhanjiang Biomass Power Plant

2012 ◽  
Vol 608-609 ◽  
pp. 242-248
Author(s):  
Jiang Tao Fang ◽  
Jing Hui Song ◽  
Zhi Gang Zhan ◽  
Ji Li
Keyword(s):  
Power Plant ◽  
Circulating Fluidized Bed ◽  
Gas Temperature ◽  
Unit Load ◽  
Bed Temperature ◽  
Pollutants Emission ◽  
Secondary Air ◽  
And Performance ◽  
Exhaust Gas Temperature ◽  
Biomass Power Plant

Circulating Fluidized Bed (CFB) biomass-fired technology is emerging biomass utilization technology for its advantages of wide adaptability of fuels, stable combustion, low-pollutants emission, and high boiler efficiency. This paper first makes literature survey of on-site combustion adjustment and performance tests and analyzes main influenced factors on combustion adjustment for CFB biomass-fired boiler, including unit load, bed temperature, bed pressure, fuel characteristics, primary air, secondary air, air ratio, circulating ash. Then combustion adjustment characteristics are studied on the largest-scale biomass-fired power project in China - 2×50MW CFB biomass-fired power plant in Zhanjiang by Guangdong Yudean Group. Main influenced factors and principle problems of combustion adjustment tests such as unit load, bed temperature, fuel deflagration, oxygen content, and exhaust gas temperature are tested and analyzed. Optimized operation suggestions are proposed according to the combustion adjustment tests.

scholarly journals Experimental Investigation of Oxygen Carrier Aided Combustion (OCAC) with Methane and PSA Off-Gas

2020 ◽  
Vol 11 (1) ◽  
pp. 210
Author(s):  
Viktor Stenberg ◽  
Magnus Rydén ◽  
Tobias Mattisson ◽  
Anders Lyngfelt
Keyword(s):  
Oxygen Carrier ◽  
Silica Sand ◽  
Fuel Conversion ◽  
Fuel Gas ◽  
Bed Temperature ◽  
Bed Materials ◽  
Distribution Plate ◽  
Bed Material ◽  
Gas Conversion ◽  
No Emissions

Oxygen carrier aided combustion (OCAC) is utilized to promote the combustion of relatively stable fuels already in the dense bed of bubbling fluidized beds by adding a new mechanism of fuel conversion, i.e., direct gas–solid reaction between the metal oxide and the fuel. Methane and a fuel gas mixture (PSA off-gas) consisting of H2, CH4 and CO were used as fuel. Two oxygen carrier bed materials—ilmenite and synthetic particles of calcium manganate—were investigated and compared to silica sand, an in this context inert bed material. The results with methane show that the fuel conversion is significantly higher inside the bed when using oxygen carrier particles, where the calcium manganate material displayed the highest conversion. In total, 99.3–99.7% of the methane was converted at 900 °C with ilmenite and calcium manganate as a bed material at the measurement point 9 cm above the distribution plate, whereas the bed with sand resulted in a gas conversion of 86.7%. Operation with PSA off-gas as fuel showed an overall high gas conversion at moderate temperatures (600–750 °C) and only minor differences were observed for the different bed materials. NO emissions were generally low, apart from the cases where a significant part of the fuel conversion took place above the bed, essentially causing flame combustion. The NO concentration was low in the bed with both fuels and especially low with PSA off-gas as fuel. No more than 11 ppm was detected at any height in the reactor, with any of the bed materials, in the bed temperature range of 700–750 °C.

A Study of Operation Performance of Circulating Fluidized Bed Combustion Boiler

2003 ◽  
Author(s):  
Zhengshun Wu ◽  
Hanping Chen ◽  
Dechang Liu ◽  
Jie Wang ◽  
Chuangzhi Wu ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Operation Performance ◽  
Cfb Boiler ◽  
Bed Temperature ◽  
Suitable Temperature ◽  
Bed Material ◽  
Circulating Fluidized Bed Combustion

The operation performance of circulating fluidized bed combustion (CFBC) boiler was studied in this paper. The experimental results indicate that the load of CFB boiler has linear relation with bed temperature and bed material height of operation. By multiple regression analysis, the relation of the load of CFB boiler with bed temperature and bed material height of operation can be expressed as a formula. The suitable temperature and the bed material height corresponding to the load of CFB boiler can be found using the formula; the problem of the boiler to be blindly operated can be reduced in practice.

Temperature and gas concentration profiles in a circulating fluidized-bed combustor burning an Indian coal

2000 ◽  
Vol 214 (3) ◽  
pp. 281-286
Author(s):  
S De ◽  
P K Nag
Keyword(s):  
Circulating Fluidized Bed ◽  
Carbon Dioxide Concentration ◽  
Concentration Profiles ◽  
Gas Concentration ◽  
Indian Coal ◽  
Bed Temperature ◽  
Riser Height ◽  
Bed Material ◽  
Fluidized Bed Combustor ◽  
Insight Into

An experimental investigation has been carried out to study the bed temperature and gas concentration profiles due to combustion of an Indian coal in a laboratory-scale circulating fluidizedbed (CFB) combustor of 102 mm x 102mm cross-section and 5.25 m high, made of insulating firebricks. As the sulphur content of the coal burned was low, no sorbent was used. Sand acted as the bed material. The results are discussed for four different superficial velocities at a constant coal feed rate. The temperature of the bed was essentially uniform for each of the superficial velocities used. The oxygen concentration decreases along the riser height showing that combustion continues over its entire length. The carbon monoxide concentration decreases along the riser except only near the top. The carbon dioxide concentration, however, increases along the riser except near the top. The of NOx is also discussed, as it is a significant pollutant from coal combustion. The results are explained to obtain some insight into the combustion of coal in a CFB.

Application of Fluidization Reconstruction Energy-Saving Combustion Technology on 300MW CFB Boiler

2012 ◽  
Vol 516-517 ◽  
pp. 140-145 ◽  
Author(s):  
Jian Min Su ◽  
Nan Hu
Keyword(s):  
Energy Saving ◽  
Performance Improvement ◽  
Circulating Fluidized Bed ◽  
Heating Surface ◽  
Cfb Boiler ◽  
Auxiliary Power ◽  
Combustion Technology ◽  
High Power Consumption ◽  
Combustion Tests ◽  
Bed Material

Aiming at high power consumption by auxiliaries of circulating fluidized bed (CFB) boiler, combustion tests were carried out on a 300MW inferior anthracite fired CFB boiler to decrease the bed material inventory via energy saving combustion technologies for CFB boiler based on fluidization reconstruction. The effects of fluidization reconstruction on boiler performance improvement were analyzed. Application practices show that after fluidization reconstruction, the power consumed by auxiliaries of the CFB boiler decreases obviously. Auxiliary power ratio of the 300MW boiler unit has been reduced from 6.1% to 4.3%. The erosion of boiler heating surface has been alleviated obviously.

Study on the Contamination Coefficient of Convective Heating Surface in a Circulating Fluidized Bed Boiler

2013 ◽  
Vol 732-733 ◽  
pp. 286-290
Author(s):  
Yu Zhao Wang ◽  
Xue Min Liu ◽  
Ai Cheng Liu ◽  
Qing Liu ◽  
Jian Chun Zhang ◽  
...  
Keyword(s):  
Circulating Fluidized Bed ◽  
Collection Efficiency ◽  
Heating Surface ◽  
Surface Contamination ◽  
Convective Heating ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Cfb Boiler ◽  
Exhaust Gas Temperature

The ash deposition and the gas velocity affect the exhaust gas temperature of a CFB boiler. The surface contamination in a CFB boiler is quite different from that one in the pulverized coal boiler. It is suggested that the surface contamination in a CFB boiler should be determined according to the ash content in the fuel as well as the cyclone collection efficiency. The effect of the gas velocity on the surface contamination is very important. The lower gas velocity causes more serious contamination, leading to the higher exhaust gas temperature. The staged tube arrangement should be employed. And the gas velocity should be designed higher to enhance the self-cleaning ability. Anyway, the soot blower should be designed in the CFB boiler convective heating surface. The ratio of the practical contamination coefficient to the design one, k,is the strong function of gas velocity, wy, which was expressed as: k=1+exp(6.8-wy)

scholarly journals Concept of an Ontology for Automated Vehicle Behavior in the Context of Human-Centered Research on Automated Driving Styles

Information ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 21
Author(s):  
Johannes Ossig ◽  
Stephanie Cramer ◽  
Klaus Bengler
Keyword(s):  
Driving Behavior ◽  
Automation System ◽  
Automated Driving ◽  
Driving Style ◽  
Driving Experience ◽  
Automated Vehicle ◽  
Future Design ◽  
Vehicle System ◽  
The Future ◽  
Conceptual Distinction

In the human-centered research on automated driving, it is common practice to describe the vehicle behavior by means of terms and definitions related to non-automated driving. However, some of these definitions are not suitable for this purpose. This paper presents an ontology for automated vehicle behavior which takes into account a large number of existing definitions and previous studies. This ontology is characterized by an applicability for various levels of automated driving and a clear conceptual distinction between characteristics of vehicle occupants, the automation system, and the conventional characteristics of a vehicle. In this context, the terms ‘driveability’, ‘driving behavior’, ‘driving experience’, and especially ‘driving style’, which are commonly associated with non-automated driving, play an important role. In order to clarify the relationships between these terms, the ontology is integrated into a driver-vehicle system. Finally, the ontology developed here is used to derive recommendations for the future design of automated driving styles and in general for further human-centered research on automated driving.

scholarly journals A Roadmap for the Future Design of Human-Robot Collaboration

2020 ◽  
Vol 53 (2) ◽  
pp. 10196-10201
Author(s):  
Hans-Jürgen Buxbaum ◽  
Sumona Sen ◽  
Ruth Häusler
Keyword(s):  
Future Design ◽  
The Future ◽  
Human Robot Collaboration

scholarly journals Tripeptide Self-Assembly into Bioactive Hydrogels: Effects of Terminus Modification on Biocatalysis

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 173
Author(s):  
Marina Kurbasic ◽  
Ana M. Garcia ◽  
Simone Viada ◽  
Silvia Marchesan
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Chemical Modifications ◽  
Ability To Work ◽  
Active Compounds ◽  
Future Design ◽  
Self Organized ◽  
The Future ◽  
Bio Material ◽  
Supramolecular Catalysts

Bioactive hydrogels based on the self-assembly of tripeptides have attracted great interest in recent years. In particular, the search is active for sequences that are able to mimic enzymes when they are self-organized in a nanostructured hydrogel, so as to provide a smart catalytic (bio)material whose activity can be switched on/off with assembly/disassembly. Within the diverse enzymes that have been targeted for mimicry, hydrolases find wide application in biomaterials, ranging from their use to convert prodrugs into active compounds to their ability to work in reverse and catalyze a plethora of reactions. We recently reported the minimalistic l-His–d-Phe–d-Phe for its ability to self-organize into thermoreversible and biocatalytic hydrogels for esterase mimicry. In this work, we analyze the effects of terminus modifications that mimic the inclusion of the tripeptide in a longer sequence. Therefore, three analogues, i.e., N-acetylated, C-amidated, or both, were synthesized, purified, characterized by several techniques, and probed for self-assembly, hydrogelation, and esterase-like biocatalysis. This work provides useful insights into how chemical modifications at the termini affect self-assembly into biocatalytic hydrogels, and these data may become useful for the future design of supramolecular catalysts for enhanced performance.

Dynamic Modeling of CATOFIN® Fixed-Bed Iso-Butane Dehydrogenation Reactor for Operational Optimization

2016 ◽  
Vol 14 (1) ◽  
pp. 491-515 ◽  
Author(s):  
Zeeshan Nawaz
Keyword(s):  
Coke Formation ◽  
Fixed Bed ◽  
Process Intensification ◽  
Operating Conditions ◽  
Catalytic Dehydrogenation ◽  
Heating Rates ◽  
Reactor Model ◽  
Fuel Gas ◽  
Bed Temperature ◽  
Operational Optimization

AbstractThe catalytic dehydrogenation of iso-butane to iso-butylene is an equilibrium limited endothermic reaction and requires high temperature. The catalyst deactivates quickly, due to deposition of carbonaceous species and countered by periodic regeneration. The reaction-engineering constraints are tied up with operation and/or technology design features. CATOFIN® is a sophisticated commercialized technology for propane/iso-butane dehydrogenation using multiple adiabatic fixed-bed reactors having Cr2O3/Al2O3 as catalyst, that undergo cyclic operations (~18–30m); dehydrogenation, regeneration, evacuation, purging and reduction. It is always a concern, how to maintain CATOFIN® reactor at an optimum production, while overcoming gradual decrease of heat in catalyst bed and deactivation. A homogeneous one-dimensional dynamic reactor model for a commercial CATOFIN® fixed-bed iso-butane dehydrogenation reactor is developed in an equation oriented (EO) platform Aspen Custom Modeler (ACM), for operational optimization and process intensification. Both reaction and regeneration steps were modeled and results were validated. The model predicts the dynamic behavior and demonstrates the extent of catalyst utilization with operating conditions and time, coke formation and removal, etc. The model computes optimum catalyst bed temperature profiles, feed rate, pre-heating, rates for reaction and regeneration, fuel gas requirement, optimum catalyst amount, overall cycle time optimization, and suggest best operational philosophy.

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