The coal to ethylene glycol (CTEG) process has drawn much attention due to the serious conflict between supply and demand of ethylene glycol in China. However, it is inevitably accompanied by the problem of high CO₂ emissions. Carbon capture is one of the most promising potential effective ways to address this issue. However, the CTEG process, integrated with carbon capture technology, will lead to energy and economic penalties. Thus, a comprehensive evaluation of CTEG process with different CO₂ capture technologies is urgently needed. This study analyzed the technoeconomic performance of four CO₂ capture alternatives for the CTEG process: Rectisol, mono-ethanol amine (MEA), chilled ammonia process (CAP) and dimethyl carbonate (DMC) technologies. Results show the energy consumption of CO₂ capture of the Rectisol process is the lowest, 1.88 GJ/tCO₂, followed by the DMC process, 2.10 GJ/tCO₂, the CAP process, 3.64 GJ/tCO₂, and the MEA process, 5.20 GJ/tCO₂. The CO₂ capture cost of the Rectisol process is lowest, CNY 169.5/tCO₂, followed by the DMC process, CNY 193.2/tCO₂, the CAP process CNY 232.6/tCO₂, and the MEA process CNY 250.5/tCO₂. As the Rectisol technology has the best comprehensive performance, it is the best option for CTEG industry in comparison with the MEA, CAP, and DMC technologies.

High-efficiency production of xylene/trimethylbenzene from benzene/toluene with methanol is a potential way to promote the implementation on the coupled cycle development strategy of petrochemical and coal chemical industry and optimize the resource structure. At the same time, relying on the innovation of catalytic new materials, physical chemistry, intelligent capture technology, process engineering, and other principles and methods, p-xylene (PX) and trimethylbenzene (TMB) with higher added value were prepared by C_6-8~arene methylation, which could elevate the level of methylation field and improve the competitiveness of the industry. This paper focuses on the one-step methylation reaction of benzene with methanol or toluene with methanol to obtain high-purity p-xylene (BM-PX/TM-PX), and the one-step methylation reaction of xylene with methanol to obtain mesitylene (XM-TMB). The methylation reaction mechanism and the preparation strategy of a high-performance catalyst were reviewed. The high selectivity of PX obtained by precisely controlling the pore size and acid site distribution of zeolites was emphasized. Meanwhile, the current research progress of TMB, the kinetic/thermodynamics of the BM-PX/TM-PX, and XM-TMB methylation reaction were described. Based on a literature research and the conclusion of our research group, the mechanism of methylation reaction process was expounded. Finally, the new research direction of catalysts used and reaction process in methylation reaction were prospected in order to guide the rapid development of this field.

The pursuit of low-energy-consumption CO₂ capture technology has promoted the renewal and iteration of absorbents for chemical absorption. In order to evaluate the regeneration energy consumption of absorbents and obtain the distribution of energy consumption, a coupling method combining rigorous energy balance and simple estimation is proposed in this study. The data regarding energy balance and material balance from process simulation are transformed into the model parameters required in the simple estimation model. Regenerative energy consumption and distribution are determined by the empirical estimation formula. Two CO₂ capture processes of an MEA aqueous solution and MEA–n-propanol aqueous solution (phase-change absorbent) were used to verify the feasibility and applicability of the coupling method. The effects of n-propanol concentration, CO₂ loading in the lean solution, and temperature on energy consumption were discussed. The results show that the energy consumption of 30 wt% MEA aqueous solution is the lowest at 3.92 GJ·t⁻¹-CO₂ when CO₂ load in the lean solution is 0.2 mol CO₂·mol⁻¹-MEA, and the reaction heat Q_rec, sensible heat Q_sen, and latent heat Q_latent were 1.97 GJ·t⁻¹-CO₂, 1.09 GJ·t⁻¹-CO₂, and 0.86 GJ·t⁻¹-CO₂, respectively. The lowest energy consumption of the phase-change absorbent with CO₂ loading of 0.35 mol CO₂·mol⁻¹-MEA in the lean solution is 2.32 GJ·t⁻¹-CO₂. Q_rec, Q_sen, and Q_latent were 1.9 GJ·t⁻¹-CO₂, 0.29 GJ·t⁻¹-CO₂, and 0.14 GJ·t⁻¹-CO₂, respectively. This study provides a simple and meaningful method for accurately assessing absorber performance and process improvement, which can accelerate the development of economically viable, absorption-based CO₂ capture processes.