Modeling and analysis of a syngas cooler with concentric evaporator channels in a coal gasification process

Abstract

Coal gasification offers a flexible and efficient conversion of the solid fuel into CO-and H 2 -rich synthetic gas (syngas) for production of various chemicals and energy products. Since the hot syngas leaving a gasifier contains various impurities such as acidic gases and particulates, it needs to be cooled down for cleaning prior to conversion into the final product. A dedicated heat exchanger called a syngas cooler (SGC) is used to lower the gas temperature while recovering the thermal energy. This study investigated the heat transfer characteristics in a commercial-scale SGC consisting of a series of concentric helical coil channels. First, the detailed flow and heat transfer pattern in the unique heat exchanger were analyzed using computational fluid dynamics (CFD) for various operating loads and fouling conditions. The predicted heat transfer rate was used to derive correlations for Nusselt number for the channel sections of the SGC. Second, a one-dimensional model of the equipment was proposed for fast-response process simulations. In terms of heat transfer rate and gas temperature, the process model showed a reasonable accuracy compared to the CFD results for the tested cases.

Numerical Simulation of Heat Transfer and a Forging Plate Structure in a Radiant Syngas Cooler with Radiation Screens

“…Therefore, most researchers use numerical simulation methods to explore the flow and the heat transfer process of syngas in a quench chamber or a waste heat boiler. According to the different quenching materials, the quenching modes can be divided into water quenching (such as an ECUST opposed multiburner gasifier) and gas quenching (such as a Shell gasifier) . In the water quenching system, the gas flow can be simulated as turbulence, which is described by the RNG k –ε model .…”

“…The convective syngas cooler is usually set at the downstream of the RSC or gas quenching, for further heat recovery after the preliminarily cooling of syngas. The cooling pipe arrangement of a convective syngas cooler is relatively dense, and the gas flow channel is narrow, which are easy to cause a blockage. , The complex piping layout makes it difficult to clean the convective syngas cooler. Uebel et al pointed out that the radiation-quenching process had the highest thermal efficiency among various cooling methods.…”

“…According to the different quenching materials, the quenching modes can be divided into water quenching (such as an ECUST opposed multiburner gasifier) 10 and gas quenching (such as a Shell gasifier). 11 In the water quenching system, the gas flow can be simulated as turbulence, which is described by the RNG k−ε model. 12 The interface of liquid and gas is traced through a two-phase interface, and the fluid volume model is used to simulate the phase flow in the quenching chamber.…”

Numerical study on the performance of an adapted radiant syngas cooler with water spray for entrained‐flow gasifier

“…Experiments under high‐temperature and high‐pressure conditions are seriously tough to be conducted. Many numerical models have been presented for the performance of entrained‐flow gasifiers and the multiphase flow and heat transfer process in syngas cooler . Yang developed a computationally efficient reactor network model to investigate a newly designed oxygen‐staged membrane wall entrained‐flow gasifier and provided operational guidelines for improving operational economy and safety.…”

“…The heat transfer in fire‐tube waste heat boiler for bitumen gasification is simulated by a single‐phase model . Oh et al also used CFD model to analyze the detailed flow and heat transfer pattern of a syngas cooler with concentric evaporator channels for various operating loads and fouling conditions. A numerical model has been developed, and the multiphase flow field and temperature distribution in an industrial‐scale RSC have been presented in our previous papers .…”