Conceptual Design of the Coal to Synthetic Natural Gas (SNG) Process Based on BGL Gasifier: Modeling and Techno-Economic Analysis

Abstract

Developing coal to synthetic natural gas (SNG) projects in China could alleviate the conflict between supply and demand of natural gas. The coal to SNG process based on Lurgi gasifier (Lurgi process) has been commercially implemented. However, low energy efficiency and high production cost restricted expansion of Lurgi processes. BGL gasifier developed based on Lurgi gasifier is considered to be more appropriate for coal to SNG projects. In this work, a novel BGL gasifier based coal to SNG process (BGL process) is proposed and simulated based on rigorous kinetics models. Based on simulation, techno-economic analysis and comparison is conducted over the conventional Lurgi process. The results show that objective energy efficiency of the BGL process is 8% larger than that of the Lurgi process, while increase of general energy efficiency is not obvious. Considering the income of product, ROI (return on investment) of the BGL process is 3% higher than that of the Lurgi process. However, the Lurgi process can produce more byproducts. If considering values of these byproducts, the BGL process will not be economically competitive.

Modeling and Analysis of Coal-Based Lurgi Gasification for LNG and Methanol Coproduction Process

“…The trend of syngas composition changing is similar under different operating pressures. We then study the effect of the unreacted gas recycling ratio to the conversion (a) and the compression duty for gas recycling (b), as shown in Figure 10a, However, the H:C ratio of syngas for methanol synthesis should not exceed 2.1 [38]. When the H:C ratio decreases to 2.1 and the pressure is 31.1 bar, the increase of inert gas content is less than that at 21.1 bar.…”

Techno‐Economic Analysis of a Coal Staged Conversion Polygeneration System for Power and Chemicals Production

“…Process simulation and energy performance analysis have been carried out using the commercial simulation software Aspen Plus . As a steady‐state modeling software, Aspen Plus has been widely applied in modeling and techno‐economic analysis of the coal‐to‐SNG process , , , the coal‐based polygeneration process coupled with CO 2 capture , , coal or char gasification , , the biomass‐to‐synthetic natural gas (SNG) process , , as well as the Claus process for valuable elemental sulfur recovery . Furthermore, the software package of Aspen Plus contains many built‐in blocks, which can be directly used in the appropriate part.…”

“…Considering the complex configurations of H 2 S and CO 2 absorbers as well as the stripper for DEPG regeneration, which will result in a relatively slow convergence speed, a simplified model named Sep block is used in this work to represent the two‐stage Selexol™ process for removal of H 2 S and CO 2 from the water‐shifted syngas. To simulate the solvent properties involved in this unit, the perturbed‐chain statistical associating fluid (PC‐SAFT) property method is adopted , . Meanwhile, the results obtained by Field et al are applied to calculate the gas concentration in H 2 S‐rich gas, CO 2 ‐rich gas, and clean gas, respectively.…”