NICE’s Indirect Coal-to-Liquid Process for Producing Clean Transportation Fuels Using Fischer-Tropsch Synthesis

Abstract

China is currently the world's top coal consumer and the largest oil importer to sustain its rising economy and meet the mounting demand for transportation fuels. However, the increasing emissions due to the huge fossil fuels consumption, coupled with oil market instability, could derail China's economic growth and jeopardize its national energy security. To face such a hurdle, China has been aggressively supporting low-carbon businesses opportunuties over the past decade, has recently announced several plans to cap coal utilization, and is currently the biggest investor in clean energy technologies. Coal-to-Liquid (CTL) is one of the most promising clean coal technologies, offering an ideal solution that can meet China's energy demands and environmental expectations. It is widely known that the Shenhua Group has pioneered and is currently leading the commercialization of the Direct Coal Liquefaction (DCL) process in China.This paper highlights a part of the joint research effort undertaken by the National Institute of Clean-and-Low-Carbon Energy (NICE) and University of Pittsburgh in order to develop and commercialize the Indirect Coal Liquefaction (ICL) process. In this mission, NICE has built and operated an ICL plant including a large-scale (5.8-m ID and 30-m height) Slurry-Bubble-Column Reactor (SBCR) for Fischer-Tropsch synthesis using iron catalyst. The research, conducted at the University of Pittsburgh over the past few years, allowed building a user-friendly Simulator, based on a comprehensive SBCR model integrated with Aspen Plus and is validated using data from the NICE actual ICL plant. In this paper, the Simulator predictions of the performance of the NICE SBCR, operating with iron and cobalt catalysts under four different tail gas recycle strategies: (1) direct recycle; (2) using a Pressure Swing Adsorption (PSA) unit; (3) using a reformer; and (4) using a Chemical looping Combustion (CLC) process, are presented. It should be mentioned also that our joint research effort has laid the foundation for the design of a commercial-scale SBCR for producing one-million tons per annum of environmentally friendly and ultraclean (no sulfur, no nitrogen and virtually no aromatics) transportation fuels, which could greatly contribute to ensuring China's national energy security while curbing its lingering emission problems.

Novel Approach and Correlation for Bubble Size Distribution in a Slurry Bubble Column Reactor Operating in the Churn–Turbulent Flow Regime

“…The knowledge of gas bubble sizes and their holdups, among other parameters, is required for proper operation, modeling, and optimization of multiphase reactors , as such parameters are needed for solving reactor equations (mass, energy, and momentum balances) whether for numerical modeling or Computational Fluid Dynamics (CFD) simulations. − Intrusive and nonintrusive experimental methods have been developed and employed to investigate such parameters. , In bubble column reactors ,− and slurry bubble column reactors (SBCRs), ,− the manometric method (also known as the hydrostatic-head method) was often used to obtain the overall gas holdup; and the Dynamic Gas Disengagement (DGD) technique, coupled with a correlation relating the bubble rise velocity to the bubble diameter, such as that by Fukuma et al, was employed to calculate the gas bubble sizes as well as their corresponding holdups. This paper is mainly concerned with the behavior of gas bubbles and their holdups in SBCRs.…”