Enhancing the Potential of Methane Combined Reforming for Methanol Production via Partial CO₂ Hydrogenation

Abstract

A process for methanol production from high CO 2 content natural gas (50−60%) is presented and analyzed in technical and economic terms. A conceptual design is proposed on the basis of partial hydrogenation of the feed by the reverse water gas shift (RWGS) reaction, prior to a combined reforming operation. Both the RWGS reactor and a Lurgi-type methanol reactor were rigorously simulated via gPROMS by taking into account kinetic expressions of commercial catalysts. The mentioned reactors, the reformer, and the flash separator were all simulated as separate modules and interconnected as a whole plant. The effect of CO 2 content, feed fraction to be hydrogenated, influence of the H 2 /CO ratio and the methanol recycle ratio on the total CO 2 conversion, H 2 consumption, methanol reactor size, and CO 2 emissions were investigated. It was found that the hydrogenation of 40% of a feed containing 60% CO 2 by using a H 2 /CO 2 ratio of 1.7 followed by a combined reforming furnace leads to a syngas that has an optimum composition for methanol production. An economic analysis demonstrated that the proposed process entails lower investment costs partially due to the smaller reformer size, as compared to a methanol plant of similar production based on CH 4 steam reforming. On the other hand, the operating costs are higher mainly because of the cost of H 2 . Consequently, a negative net present value is obtained under present market prices. However, for a feed containing 50% CO 2 , the proposed process would be economically viable for a H 2 price of 2.4 US$/kg or a methanol price of 500 US$/ton. Slightly higher price variations are necessary to obtain a financially feasible project for a feed containing 60% CO 2 . Nevertheless, the reduced H 2 demand has lower economic incidence, as compared to a methanol plant based on CO 2 and H 2 as raw materials.

Direct and indirect electrification of chemical industry using methanol production as a case study

“…Despite the promising future of DR, we would like to restrain ourselves to a more conservative process to reform natural gas since the aim of this work is to assess the electrification based on current industrial technologies. Consequently, we formulate the natural gas reforming process based on the work of Olah et al [42] and Canete et al [43],…”

Optimized Process for Methanol Production via Bi-reforming Syngas

“…However, this feed ratio requires a very large amount of CH 4 compared to the amount of CO 2 . Cañete et al, , Shi et al, and Zhang et al used a feed ratio that was significantly different from the conventional 3:1:2 ratio. Zhang et al studied the effect of the bi-reforming feed ratio at steam to carbon ratios of 1.5 and 2.0.…”

“…Zhang et al studied the effect of the bi-reforming feed ratio at steam to carbon ratios of 1.5 and 2.0. Cañete et al used natural gas with a high CO 2 concentration as the feed and investigated the effect of CO 2 concentration (30, 35 and 40%) in the feed for the bi-reforming reactor. They found that higher CO 2 in the feed did not impact the conversion of CH 4 , increased the CO 2 conversion, and decreased the H 2 /CO ratio in the product stream.…”

Opportunities for CO2 Utilization in Coal to Green Fuel Process: Optimal Design and Performance Evaluation

“…As a result, the economic performance of the CO 2 -to-methanol process is greatly influenced by the cost of hydrogen production . Hydrogen produced from the electrolytic water is considered as the preferred technology; however, its application is limited by the present cost of electricity . As discussed by Atsonios et al, the electricity cost for H 2 production accounts for more than 35% of the total production cost of the new CO 2 -to-methanol process.…”

“…As discussed by Atsonios et al, the electricity cost for H 2 production accounts for more than 35% of the total production cost of the new CO 2 -to-methanol process. This is mainly because this technology requires high energy consumption, about 4.8 kWh/m 3 H 2 . Furthermore, how to effectively utilize the by-product (oxygen) of electrolytic water in a CO 2 -to-methanol process should also be well considered.…”