DEVELOPMENT OF NICKEL AND MCM-41-BASED CATALYST WITH BASIC PROMOTER FOR DRY REFORMING OF METHANE

• Main Author: Sayyidatun Nisa, Khadijah
• Format: Theses
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/55042
• Institution: Institut Teknologi Bandung

Based on data from Indonesian Ministry of Energy and Mineral Resources in 2018, potential resources of natural gas in Natuna Sea is 46 trllion standard cubic feet (TSCF), with 71%-mole CO2 and 28%-mole of CH4. Dry reforming of methane (DRM) is considered as the promising reforming technology to utilize natural gas in Natuna Sea into synthesis gas. Synthesis gas can be further utilized to produce beneficial chemicals, such as olefin, alcohol, and liquid hydrocarbon. However, challenges to commercialize dry reforming of methane are carbon deposition and sintering of catalyst at high temperature, which make the catalyst easily deactivated. Therefore, further development is needed to find catalyst with good activity and stability for DRM. Ni/MCM-41 catalyst has good potential in conducting dry reforming of methane. Nickel is a non-noble metal that is cheap, abundant, and commonly used as catalyst for commercial purpose. MCM-41 is a mesoporous silica material that has high surface area (~1000 m2/g) and good thermal stability, so that it is potential to be used as support for DRM catalyst. Other aspect that can be modified to enhance the MCM-41-based catalyst is addition of basic promoter. Aim of this research was testing the activity and stability of MCM-41-based catalyst for DRM, determine the effect of promoter type to activity and stability of MCM-41-based catalyst, and determine the effect of basic promoter addition to the amount of carbon deposition. This research has 3 steps, which are catalysts synthesis, characterization, and activity test. The catalysts are synthesized by impregnation method and calcination temperature of 700oC. XRD, N2 Physisorption, CO2-TPD, H2-TPR, and TGA were conducted to reveal physicochemical properties of the catalysts. Operating conditions that are used in activity test is atmospheric pressure, 700oC, time on stream 4 hours and WHSV=60,000 mL g-1 h-1. In this research, activity test of methanation and steam reforming catalysts that are used in fertilizer plant was conducted as comparison for MCM-41-based catalysts. Ni/MCM-41, Ni-Mg/MCM-41, Ni-Ca/MCM-41, Ni-Na/MCM-41, and Ni-K/MCM-41 are catalysts that have been synthesized. XRD characterization shows the size of NiO crystallite is 4,19 nm–6,65 nm. N2 Physisorption result shows a decrease of surface area and pore volume due to pore blockage. H2-TPR result shows that the addition of Mg and Na promoter strengthen the interaction between NiO and MCM-41. CO2-TPD result shows the addition of Mg and Ca promoter increase the capacity of CO2 adsorption of the catalyst. Furthermore, activity test of Ni/MCM-41, Ni-Mg/MCM-41, Ni-Ca/MCM-41, Ni-Na/MCM-41, and Ni-K/MCM-41 yields CH4 conversion as much as 62%, 72%, 69%, 36%, and 46% respectively. In addition, the results of CO2 conversion are 52%, 54%, 55%, 35%, and 44% respectively. All catalysts yield good stability for 240 minutes. On the other hand, commercial catalyst for methanation shows activity for only 140 minutes, with carbon deposition as much as 41%-wt. That phenomenon indicates methanation catalyst shifting the reaction towards carbon formation. Steam reforming commercial catalyst yields CH4 and CO2 conversion as much as 85% and 65% respectively, however there is decrease in H2 yield from time to time and carbon deposition of 31%-wt. It is indicated that steam reforming catalyst also shifting the reaction towards carbon formation. In this research, the effect of WHSV to 5% Ni-Mg/MCM-41 catalyst activity and simulation of approach temperature to equilibrium were also examined. Catalyst that was tested at WHSV=60.000 mL.g-1 h-1 yields higher activity than the catalyst that was tested at WHSV=72.000 mL.g-1. h-1. Catalyst at lower WHSV has more space time so that it yields higher conversion. Approach temperature to equilibrium in this research is 185oC. It can be concluded that catalysts with Mg and Ca promoter produced higher reactant conversion than Ni/MCM-41 catalyst without promoter. Furthermore, all nickel and MCM-41-based catalysts have good stability for 240 minutes. Carbon deposition that are formed in MCM-41-based catalysts is less than carbon deposition in commercial catalysts, with Ni-Ca/MCM-41 yields the highest carbon deposition of 11%-wt. Further study needs to be conducted to examine the activity of MCM-41 catalyst with time on stream more than 240 minutes.