(338g) Hydrogen Production By Methanol Reforming in the Gradient Micro-DBD Plasma Reactor

Hydrogen production by methanol reforming in the gradient micro-DBD plasma reactor

Baowei Wang*,Wenjie Ge, Xiaofei Duan

(Key Laboratory for Green Chemical Technology of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China)

Abstract

The rise in global energy demands and the shortage of fossil fuels as well as environmental considerations have created a pressing need to seek renewable alternatives. Solar, wind, and biomass are all promising renewable resources but they are generally site-specific, intermittent and unstable. On the other hand, hydrogen has been identified as an ideal energy carrier to support sustainable energy supply and reactant due to its clean and efficient. However, to support a feasible hydrogen-based economy, it is essential to produce hydrogen cleanly and renewably [1].

Hydrogen can be manufactured from a variety of energy sources. For example, it can be produced from hydrogen carriers, such as methanol and ethanol. Methanol has merits of being liquid phase, having high hydrogen to carbon ratio and getting from biomass.

In recent years, many types of non-thermal plasma reactors for hydrogen production have been implemented such as gliding arc micro-reactor [2], dielectric barrier discharge micro-reactor [3] and microhollow cathode discharge reactor [4]. These reactors processes may provide significant advantages in terms of fast reactions and energy efficiency. But the selectivity for the goal products and the conversion of the methanol are not considerable high.

A new design of a gradient micro-DBD (Gm-DBD) plasma reactor in figure 1 (2#, 3#) is preliminarily investigated for the reforming of methanol to various useful products. In methanol reforming by Gm-DBD reactor under ambient conditions, hydrogen and carbon monoxide are dominantly produced. The conversion of methanol reaches 81.3%, which is much higher than this in the conventional micro-DBD reactor in figure 1 (1#). The changes of electron temperature and electron density distribution, the high energy density can get in Gm-DBD reactor, as compared to conventional micro-DBD reactor.

The results show that the conversion of methanol depends on the form of gradient electrode. Our previous woke proved that the methanol reforming in the plasma reactor is depend on energy density and residence time [5]. The electrons generated in high energy density have more energy to break down the strong C-O bond in methanol, leading to more decomposition of methanol molecules. The long residence time make more contact time for the reactant species to collide with electrons and more time to the free radicals recombination in the reactor. In the Gm-DBD reactor the discharge gap effects of energy density and residence time. The energy density increases with the decreases of discharge gap and the residence time increases with the discharge gap. The highest conversion of methanol is found in 3# reactor. Firstly, the discharge gap is small, the energy density is high, more methanol molecules decompose to generate of more desirable species. Then the discharge gap increase, since discharge space and residence time increase with electrode gap, the number of collisions among the methanol molecules and the electrons, at the same time, the free radicals can recombine in the reactor, completely.

From the results, we found that the high energy density make more methanol molecules decompose. The long residence time lead more contact time for the reactant species to collide with electrons and more time to the free radicals recombination in the reactor. Under this operating condition, the highest methanol conversion can be got.

References

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