Solar thermal power cycle with integration of methanol decomposition and middle-temperature solar thermal energy

Solar Energy ◽  
2005 ◽  
Vol 78 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Jun Ji ◽  
Zhifeng Wang ◽  
Ruixian Cai
2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Jun Sui ◽  
Jun Ji

Solar thermochemical processes inherently included the conversion of solar thermal energy into chemical energy. In this paper, a new mechanism of upgrading the energy level of solar thermal energy at around 200°C was revealed based on the second law thermodynamics and was then experimentally proven. An expression was derived to describe the upgrading of the energy level from low-grade solar thermal energy to high-grade chemical energy. The resulting equation explicitly reveals the interrelations of energy levels between middle-temperature solar thermal energy and methanol fuel, and identifies the interactions of mean solar flux and the reactivity of methanol decomposition. The proposed mechanism was experimentally verified by using the fabricated 5kW prototype of the receiver∕reactor. The agreement between the theoretical and the experimental results proves the validity of the mechanism for upgrading the energy level of low-grade solar thermal energy by integrating clean synthetic fuel. Moreover, the application of this new middle-temperature solar∕methanol hybrid thermochemical process into a combined cycle is expected to have a net solar-to-electric efficiency of about 27.8%, which is competitive with other solar-hybrid thermal power plants using high-temperature solar thermal energy. The results obtained here indicate the possibility of utilizing solar thermal energy at around 200°C for electricity generation with high efficiency by upgrading the energy level of solar thermal energy, and provide an enhancement to solar thermal power plants with the development of this low-grade solar thermochemical technology in the near future.


2007 ◽  
Vol 129 (4) ◽  
pp. 378-381 ◽  
Author(s):  
Hongguang Jin ◽  
Jun Sui ◽  
Hui Hong ◽  
Zhifeng Wang ◽  
Danxing Zheng ◽  
...  

This paper manufactured an original middle-temperature solar receiver/reactor prototype, positioned along the focal line of one-axis parabolic trough concentrator, representing the development of a new kind of solar thermochemical technology. A 5kW prototype solar reactor at around 200–300°C, which is combined with a linear receiver, was originally manufactured. A basic principle of the design of the middle-temperature solar reactor is identified and described. A representative experiment of solar-driven methanol decomposition was carried out. Experimental tests were conducted from 200°C to 300°C under mean solar flux of 300–800W∕m2 and at a given methanol feeding rate of 2.1L∕h. The conversion of methanol decomposition yielded up to 50–95%, and the efficiency of solar thermal energy conversion to chemical energy reached 30–60%. The experimental results obtained here prove that the novel solar receiver/reactor prototype introduced in this paper can provide a promising approach to effectively utilize middle-temperature solar thermal energy by means of solar thermochemical processes.


Author(s):  
Hongguang Jin ◽  
Hui Hong ◽  
Jun Ji ◽  
Zhifeng Wang ◽  
Ruixian Cai

In this paper, we have proposed a novel solar–driven combined cycle with solar upgrading of methanol in middle temperature solar collectors, and investigated the effects of integration of solar thermal energy and methanol decomposition on the performance of the proposed cycle. The process of solar upgrading methanol is a catalytically endothermic decomposition reaction and proceeds in a range of 130–250° C. As a result, the proposed cycle has a breakthrough performance, with net solar–to–electric efficiency of 32.93% at the collector temperature of 220° C, and the turbine inlet temperature of 1062° C, superior to that of the present advanced cycle (REFOS of 20%). The exergy loss in indirect combustion of methanol proposed here is 7.5 percent points lower than that of the direct combustion. The optimum pressure ratio for thermal efficiency is approximately equal to 14. A key point emphasized here is that the proposed new cycle can utilize middle–temperature solar collector with lower cost. The promising results obtained here indicated that this novel solar–driven combined cycle could make a breakthrough in field of solar thermal power generation through integration of solar thermal energy and effective use of synthetic clean fuel.


2010 ◽  
Vol 35 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Jun Sui ◽  
Qibin Liu ◽  
Jianguo Dang ◽  
Dong Guo ◽  
Hongguang Jin ◽  
...  

2014 ◽  
Vol 699 ◽  
pp. 449-454 ◽  
Author(s):  
Shaharin Anwar Sulaiman ◽  
Farid Fawzy Fathy Taha

Malaysia has great potential for biomass stock. The fact that oil palm fronds contain high moisture content makes it unsuitable to be used directly as a biomass fuel neither for direct combustion nor gasification. Conventional and costly drying methods make the fronds a non-attractive fuel especially in humid tropical countries, where sources of biomass is abundant. A new solar dryer design is proposed that utilizes concentrated solar thermal energy for drying oil palm fronds. A prototype for the dryer has been fabricated and tested. The system’s target is to maximize the thermal energy received by the system and to minimize energy loss out of the system. Experiments were performed on samples of oil palm fronds at a drying temperature not exceeding 110°C; in order not to affect the organic material of the biomass. Results were compared with another experiment performed at the same temperature. An electric oven was used for drying. The samples were completely dried using the proposed system for 6.5 hours, compared to 10.5 hours by using the electric oven. The proposed system achieved an average drying rate of 4.75 g/hr compared to an average drying rate of 2.83 g/hr using the electric oven. The efficiency of the dryer was calculated to be 55.4%, implying good potential of the proposed system.


Author(s):  
K. Bammert ◽  
A. Sutsch ◽  
M. Simon ◽  
A. Mobarak

An alternative solution for solar energy conversion to the heliostat-tower and solar farm (parabolic trough) concept is presented in the form of large parabolic dish collectors using small high temperature gas turbines for producing electricity from solar thermal energy. A cost and efficiency comparison for the different solar thermal power plants has shown that the large parabolic dish with gas turbine set is a superior system design especially in the net power range of 50 to 2000 kW. The important advantages of the large parabolic dish concept are discussed. For the important components such as the gas turbo converter, the receiver and the parabolic dish collector, design proposals for economic solutions are presented. An advanced layout for a 250-kW gas turbo converter with recuperator is presented in detail.


2010 ◽  
Vol 171-172 ◽  
pp. 223-228
Author(s):  
Guan Sheng Chen ◽  
Ren Yuan Zhang ◽  
Feng Li ◽  
Shi Dong Li ◽  
Li Zhang

Phase change thermal storage used metal as phase change material (PCM) is an important mode of solar thermal energy storage. In this paper, the heat charging processes of solar heating units were simulated under three kinds of heating flux 100,150 and 200kW/m2 at the bottom face respectively, while the thickness of heat receiving layer at the bottom was in 5, 10 and 15mm. Al-Si alloy was selected as PCM used in the cylindrical body of the units which were in the size of φ1000×1000mm. The change of temperature and solid-liquid phase change interface of Al-Si alloy were analyzed to find out the suitable absorber thickness of thermal energy storage units which can run safety under the condition of temperature 700~900K and heat flux 100~200kW/m2, such as the application of solar thermal energy storage unit in high temperature solar thermal power stations. In the last a test system was built up and the experimental result was close to the simulation value of a unit in the size of φ300×1000×10mm.


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