Match!
Runxia Cai
Tsinghua University
12Publications
4H-index
55Citations
Publications 14
Newest
Abstract The world first 550-MWe ultra-supercritical circulating fluidized bed (CFB) boiler is designed with integrated recycle heat exchangers (INTREX) and internal solid circulation. In this research, in order to investigate the heat transfer behavior and the significance of the internal circulation, the operation characteristics of the four INTREXes as final superheaters including heat transfer coefficients and ash flow rates under different load conditions are experimentally studied. The cal...
Source
Source
#1Runxia CaiH-Index: 4
#2Xiwei KeH-Index: 1
Last.Man ZhangH-Index: 9
view all 9 authors...
With the stringent emission regulation taking effect, it is difficult for the conventional desulfurization technology in circulating fluidized bed (CFB) boilers to meet the requirements on ultra-low SO2 emission. Therefore, in this paper, the application of natural ultrafine limestone, with Sauter mean diameter of less than 20 μm, was tested by conducting bench-scale, pilot-scale and commercial-scale experiments to realize the highly efficient desulfurization in CFB furnaces. In the past, such s...
Source
#1Runxia CaiH-Index: 4
#2Yiqun HuangH-Index: 1
Last.Junfu LyuH-Index: 4
view all 8 authors...
Limestone particle size has a crucial influence on SO2 capture efficiency, however there are few studies on the sulfation reactivity, which covers a broad range of particle sizes at low SO2 concentrations. In this paper, a large-capacity thermogravimetric analyzer (LC-TGA) was developed to obtain the sulfur removal reaction rate under a wide range of particle sizes (3 μm–600 μm) and SO2 concentrations (250 ppm–2000 ppm), and then compared with the results of a traditional fixed bed reactor and a...
Source
#1Yuge Yao (THU: Tsinghua University)
#2Runxia Cai (THU: Tsinghua University)H-Index: 4
Last.Junfu Lyu (THU: Tsinghua University)H-Index: 4
view all 6 authors...
Abstract It is very important to accurately measure the tube-wall temperature of the high-temperature heating surface in the boilers with high steam parameters such as supercritical circulating fluidized bed (CFB) boilers. However, the severe abrasion problem caused by high solid concentration in CFB boilers hinders a direct tube-wall temperature measurement in CFB boilers. In this paper, a new method which embeds thermocouples in deposited metal on the heating surface was proposed to solve this...
Source
#1Xiwei Ke (THU: Tsinghua University)H-Index: 1
#2Dongfang Li (PNU: Pusan National University)H-Index: 1
Last.Hairui Yang (THU: Tsinghua University)H-Index: 19
view all 8 authors...
Abstract It is difficult to maintain enough high circulating ash rate in circulating fluidized bed (CFB) boilers if they burn the Indonesian coals due to their low ash content. Hence, the ash formation data for these coals is of significance to assessing mass balance in CFB boilers. Two kinds of Indonesian coal that were burned in the 550 MW supercritical CFB boilers in Korea, Kideco and KCH, were tested with static combustion and cold sieving method to study their ash formation characteristics....
1 CitationsSource
#1Runxia Cai (THU: Tsinghua University)H-Index: 4
#2Man Zhang (THU: Tsinghua University)H-Index: 9
Last.Junfu Lyu (THU: Tsinghua University)H-Index: 4
view all 9 authors...
Abstract External heat exchangers (EHEs) are widely used in many industrial fields for heat absorption, such as circulating fluidized bed combustion, solar energy generation, etc. However, considerable deviation of tube wall temperatures was found in the commercial EHEs, which will result in the overheating of tubes and affect the safe operation. In order to investigate the non-uniform heat transfer phenomenon, local heat transfer and hydrodynamics with a horizontal tube and a vertical tube as w...
Source
#1Xiwei Ke (THU: Tsinghua University)H-Index: 1
#2Runxia Cai (THU: Tsinghua University)H-Index: 4
Last.Hairui Yang (THU: Tsinghua University)H-Index: 19
view all 6 authors...
Abstract Circulating fluidized bed (CFB) boilers face sever challenges in China due to the new ultra-low emission rules, more specifically, the NOx emission must be lower than 50 mg/m3. In this paper, NOx evolution inside CFB furnaces and the gas-solid flow characteristics were reviewed. It is found that NOx emission can be reduced through re-specification of fluidization state, namely, improving the bed quality. A low NOx emission (de-NOx) technology applied to CFB boilers was thus proposed. Th...
1 CitationsSource
#1Runxia Cai (THU: Tsinghua University)H-Index: 4
#2Man Zhang (THU: Tsinghua University)H-Index: 9
Last.Hairui Yang (THU: Tsinghua University)H-Index: 19
view all 6 authors...
Abstract Severe pressure fluctuations in parallel external loops were found in the circulating fluidized bed (CFB) boilers recently, so a CFB test rig with two external loops was established to investigate the unstable performance of parallel external loops. A long-length horizontal section was used in the loopseal to intensify the impact of gas flow inside horizontal section on solid circulation rate, and CO 2 tracer method was used to detect the variation of gas flow rate in the horizontal sec...
Source
#1Runxia Cai (THU: Tsinghua University)H-Index: 4
#2Hai Zhang (THU: Tsinghua University)H-Index: 19
Last.Guangxi Yue (THU: Tsinghua University)H-Index: 17
view all 6 authors...
Abstract In this paper, the design principle of Fluidization State Specification (FSS) is reviewed and its applications in CFB boiler are introduced. In the early 2000s, FSS design principle was proposed to determine the fluidization state in the upper furnace as the basis of engineering design. The principle was initially adopted by engineers to select a proper superficial gas velocity to prevent the severe erosion on water walls. It was used in many CFB furnace designs including the world's la...
13 CitationsSource
12