**Abstract**

The slurry bed reactor has many advantages, which make it very suitable for gas-to-liquid processes, especially for the highly exothermic reactions. This chapter reviews three types of slurry bed reactors and their comparisons, including the mechanically stirred slurry reactor, bubble column slurry reactor and three-phase fluidized bed reactor. The application of the slurry bed reactors in carbon one (C1) chemistry for syngas conversion to different valuable chemicals is presented, which includes four typical exothermic reactions, that is, the Fischer-Tropsch synthesis to oil, methanol synthesis, dimethyl ether synthesis and synthetic natural gas synthesis. The operation parameters and performance of slurry bed reactor, fixed bed reactor and fluidized bed reactor are compared while discussing the reasons of catalyst deactivation. Since, the development trend of slurry bed reactor for C1 chemistry is finally proposed.

**Keywords:** slurry bed reactor, carbon one chemistry, syngas conversion, metal catalyst, deactivation

## **1. Introduction**

The slurry bed reactors are gas-liquid-solid three-phase reactors, which are commonly used in many industrial processes [1, 2]. The research of slurry bed reactors can be traced back to the Second World War, where the most studied and the earliest application process is the low-temperature Fischer-Tropsch synthesis (FTS) to oil. The catalytic reactions in slurry bed reactors are highly complicated due to the presence of multi-phase mass transfer, intraparticle diffusion, adsorption, surface reaction and desorption of products [3, 4]. The difficulty in separating the catalyst and handling of the slurry limits the application of slurry reactors in continuous processes. However, the slurry bed reactors possess many advantages, such as the low investment cost and simple construction, high heat exchange efficiency, online catalyst addition and withdrawal [5]. Moreover, the catalyst consumption per unit product is only 30% of the fixed bed reactor, and the total amount of required catalyst for the slurry bed reactor can be greatly reduced, which make it very suitable for gas-to-liquid processes [6].

In this review, the difference in three types of slurry bed reactors is compared, including the mechanically stirred slurry reactor, bubble column slurry reactor and three-phase fluidized bed reactor. The second part shows the application of slurry bed reactors for C1 chemistry, discussing the four typical exothermic reactions for syngas

conversion to different valuable chemicals. The third part introduces the comparison between slurry bed, fixed bed, and fluidized bed reactors. The fourth part discusses the catalyst deactivation for syngas conversion in slurry bed reactors, which mainly includes the catalysts sintering, carbon deposition and effects of water on catalyst structure. While, the last part demonstrates the development trend of slurry bed reactors for carbon one chemistry.
