Construction and optimization of capacity optimization evaluation system for Coal-To-Olefin and Coal-To-Gas industries

During the latter stage of the 14th Five-Year Plan period, the coal-to-olefin and coal-to-gas industries in China have been confronted with the risk of excessive industrial investment. Therefore, it is imperative to achieve incremental regulation through capacity optimization. To address this issue, an energy consumption evaluation system for coal-to-olefin and coal-to-gas projects was established. First, relevant industrial policies were systematically reviewed, and a carbon emission intensity indicator was introduced to preliminarily construct the energy consumption evaluation system. Subsequently, through enterprise investigations, data related to production processes and equipment, resource and energy consumption, and cleaner production were collected. Based on the analysis of these data, the evaluation system was further refined, thereby enabling a scientific prediction of the optimized increment of newly added capacity in the coal-to-olefin and coal-to-gas industries. The results indicate that, for the coal-to-olefin industry, the benchmark and advanced levels of energy consumption, without considering the deduction of feedstock energy consumption, are recommended to be 3 100 and 2 800 kg of standard coal per ton, respectively. In addition, the benchmark and advanced levels of water consumption are suggested to be 22 and 16 m³/t, respectively, while the benchmark and advanced levels of carbon emission intensity are proposed as 10.0 and 7.1 tons of CO₂ per ton, respectively. For the coal-to-gas industry, the benchmark and advanced levels of energy consumption are recommended to be 1 300 and 1 200 kg of standard coal per thousand normal cubic meters, respectively. Correspondingly, the benchmark and advanced levels of water consumption are suggested to be 5.5 and 5.0 m³ per thousand normal cubic meters, respectively, whereas the benchmark and advanced levels of carbon emission intensity are proposed as 5.3 and 3.6 tons of CO₂ per thousand normal cubic meters, respectively. By applying the refined energy consumption evaluation system, both under-construction and proposed projects can be systematically assessed. The evaluated samples cover 4.4 million tons per year of coal-to-olefin production capacity and 20 billion cubic meters per year of coal-to-gas production capacity. The assessment results further indicate that approximately 40.91% of the coal-to-olefin production capacity and 50% of the coal-to-gas production capacity still require further process optimization before project approval can be granted.