Experimental study on a methanol auto-thermal reforming for compact reformer

Abstract

Performance of self-sustaining methanol auto-thermal reforming (ATR) was investigated experimentally in order to elucidate a reforming reaction mechanism and a condition required for high purity H 2 production for compact reformer. The reformer consists of vaporizing and reforming sections in a single unit. The exothermic oxidation and endothermic steam reforming (STR) take place simultaneously in the reforming section. The reforming section is surrounded by the vaporizing section and then the heat for vaporization is supplied from the reforming section. Two types of exothermic oxidation reaction were investigated as the heat source for STR; one is a partial oxidation (POX) and the other is a total oxidation (TOX). CuO/ZnO/Al 2 O 3 catalyst and Pt/Al 2 O 3 catalyst were used for STR and POX, respectively. While, only CuO/ZnO/Al 2 O 3 catalyst was needed for TOX because TOX took place when fuel and oxygen were supplied to the CuO/ZnO/Al 2 O 3 catalyst. Experiments were investigated in the range of oxygen/carbon ratio (O/C ratio) 0.1-1.5, steam/carbon ratio (S/C ratio) 1.0-3.0 and N 2 mole ratio 79-50 % in oxidizer. The results showed that the H 2 formation reached maximum at around O/C=0.4 in both STR/POX and STR/TOX cases in the present study. When O/C ratio is decreased from 0.4, heat formation by the oxidation reactions decreases and is insufficient to reform residual CH 3 OH by STR. As a result, H 2 formation and the methanol conversion ratio decrease. When O/C ratio is increased from 0.4, the H 2 formation decreases, because methanol is consumed with the excess O 2 by TOX and CH 3 OH for STR decreases. After all, O/C=0.4 gives an appropriate balance of heat supply and methanol for H 2 production. These results elucidate that the reaction rate of oxidation reactions, POX and TOX, is much faster than that of STR. In other words, methanol is first consumed by the oxidation reaction and the residual methanol is used for STR. For S/C ratio, H 2 formation is decreased in the higher S/C ratio. N 2 mole ratio in oxidizer has few influence over the reforming gas. The chemical equilibrium calculations support the experimental results.

Investigation of Renewable Energy Use in the P2x Technology

“…In 2011, Svartsengi, near Grindavik, Iceland, built the world's largest renewable energy power-to-methanol plant (The George Olah Renewable Methanol Plant) [38]. As of 2015, the annual output of renewable methanol reached 4,000 tons, and the annual carbon dioxide absorption was 5,500 tons [39].…”

“…The theoretical energy efficiency of synthetic ammonia, methane, methanol, and oil calculated by chemical equations is 88.49%, 83.48%, 88.09%, and 78.17%. However, due to synthetic ammonia and methanol's high reaction pressure requirements, the electricity consumption in the larger synthesis process, overall energy efficiency are lower [39]. Comparing the marginal electricity price index, based on the market prices of four chemical products, taking Sichuan Province, a major hydropower and chemical industry province, as an example, the electricity price for large industries is about 0.5 yuan/kWh, and the electricity chemical technology is temporarily not economical at this price.…”