## 4 Conclusions  
In the present study, a numerical modeling approach was used for heat and fluid transfer and conversion reaction prevalence in the COS hydrolysis reactor of an IGFC syngas production plant. Various performance parameters and their individual effect on the reactor performance were investigated, with the main emphasis being placed on the result analysis of the methods of numerical modeling. The analysis results are as follows:  
* With other parameters fixed, the COS conversion rate decreased with increased GHSV. This is attributed to the increased reactant amount afforded by the higher GHSV, thus decreasing the conversion rate of COS.
* The COS conversion rate increased by 9.2% with a longer length ratio under the same GHSV and reactor tube wall temperature. This is caused by the more facile heat transfer and gas diffusion along and inside of a reactor tube with a larger length ratio.
* The COS conversion rate increased by a maximum of 19.3% with increased reactor wall temperature with the GHSV and length ratio unchanged. However, this results in a higher energy cost, and a more efficient setting of temperature is needed.
* A Monte Carlo simulation was performed under a 3\(\sigma\) level for more stable and reliable operation control, and operational process efficiency was modeled within an individual parameter variation range. This confirmed the maximum possible COS conversion rate of 95% with a reliability level of 98.9%.
* Within the limit of sensitivity evaluation of individual parameters, temperature was rated as the most sensitive (57.3%) with GHSV as the next most sensitive (\(-\)38.6%) parameter.  
The design of the experiment method was suggested to estimate a numerical modeling analysis method considering the COS conversion rate and probability distribution of design and operational parameters for the COS hydrolysis reactor design. Monte Carlo simulation was also performed for a more efficient stochastic analysis and estimate.  
The present numerical modeling and analysis method could ensure more accurate estimates of the COS hydrolysis reaction for more efficient design criteria. More specifically, heat and fluid transfer and  
Figure 10: Probability distribution of the COS conversion rate and sensitivity of performance parameters in the COS hydrolysis reactor.  
COS conversion within the (catalytic) reaction area inside of the COS reactor were comprehensively modeled for a more reliable estimate of operation and design of the COS reactor.  
[PERSON] makes substantial contributed to the conceptualization, composition and interpretation of the paper, the estimation and analysis of flow chemical reactivations, writing the article and revising it for each content. [PERSON] covered to the stochastic analysis and estimate by Monte Carlo simulation. [PERSON] makes the design and operating environment of the system, and funding. [PERSON] makes substantial contributed to the conceptualization design and organized structure, and revising the paper critically for important intellectual content. All researchers participated in Writing-Review & Editing.  
This research was funded by Korea Institute of Energy Technology Evaluation and Planning (KETEP), the Ministry of Trade, Industry & Energy (MOTIE), Korea Electric Power Corporation and Korea Western Power Co. Ltd. grant number No. 20163010050080.  
This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20163010050080).  
The authors declare no conflict of interest.