Application of Aerosol Nanocatalysis Technology in Methane Steam Reforming

Steam Methane Reforming (SMR) is the main method to obtain synthesis gas in production of alcohol, ammonia, acids Fischer-Tropsch synthesis and other organic products. The study has investigated the reaction of SMR and it mechanism, explained the aerosol nanocatalysis (AnC) vibrated bed as alternative technology instead of using heterogeneous catalyst in bed. The research has proven that NiO is the best catalyst that could be used in the reaction of SMR by AnC after investigating catalysts: Fe2O3, K-905D2, GIAP-8, Co2O3 and NiO.


Introduction
Synthesis gas (syngas) is a gaseous mixture containing mainly hydrogen, carbon monoxide, and carbon dioxide in various amounts [1]. It could be defined in other resources such as [2], [3] and [4] as only mixture of hydrogen and carbon monoxide without carbon dioxide. In most cases, these three compounds constitute more than 90% of the syngas, but other components including methane and inert gases such as nitrogen and argon are often present in the mixture. In recent years, new areas have emerged that may open the way for an increased production and use of synthesis gas. One example is the large-scale production of syngas using synthetic hydrocarbon fuels, produced by the Fischer-Tropsch synthesis. Similarly, a considerable effort is currently being undertaken in the development and commercialization of various types of fuel cells for both small-and large-scale power productions [1].
Syngas are indispensable in chemical, oil, and energy industries. They are important building blocks and serve as feedstocks for the production of chemicals such as ammonia and methanol. Hydrogen is used in petroleum refineries to produce clean transportation fuels, and its consumption is expected to increase dramatically in the near future as refiners need to process increasingly heavier and sour crudes [4].
Natural gas is the largest source of syngas at present and its use for this purpose is  E78 growing. Methane is the chief constituent by far of natural gas. Petroleum fractions are the next largest syngas source at present and significant quantities of syngas are being made from coal [2].
Methane conversion is the main industrial method to obtain syngas for ammonia production, alcohol, acids, Fischer-Tropsch synthesis and other products. There are several ways of conversion: aerial, steam aerial, oxygenous, steam oxidation of methane…etc [5].
Natural gas is an odorless and colorless naturally occurring mixture of hydrocarbon and nonhydrocarbon gases found in porous geologic formations beneath the earth's surface, often in association with petroleum or coal. The principal constituent is methane (CH 4 ) and its composition is regionally dependent. In Iraq the composition of natural gas as the following: Methane 55.7%, Ethane 21.9%, propane 6.5%, H 2 S 7.3%, and CO 2 3% [4].
Methane reacts with steam in the presence of a supported nickel catalyst to produce a mixture of CO and H 2 , also known as synthesis gas or syngas as represented by Equation (1) .
This reaction is also referred to as steam methane reforming (SMR) and is a widely practiced technology for industrial production of H 2 . However, the SMR is not really just one reaction as indicated in Equation (1) but involves contributions from several different catalyzed reactions such as watergas shift (WGS), reverse watergas shift (RWGS), CO disproportionation (Boudouard reaction), and methane decomposition reactions as described in Equations 2 -5 : The process carries out in the pipe oven with heating and heterogenic catalyst. The properties of catalyst show the effect on productivity of pipe oven and its lifetime. This phase is one of the most expensive with high energy in modern technological schemes [6].
The mechanism of SMR reaction with catalyst can be expressed by the following [5] particles are sized between 1 and 100 nanometers [9].
In AnC technology, the catalytic system consists of glass bullets (d = 1.1 mm) that could be represents as a dispersed material and powder of catalyst (size for about 5u10 -5 m). During vibration process appears catalyst abrasion till size of 10 -7 -10 -9 m. The changing of catalytic system structure is illustrated in the figure (2). As it has shown in (figure. 2 a) the catalytic system (without mechanical action (vibration)) is inert material and catalyst microparticles, under the vibration over the system appears fragmentation of catalyst by inert material to nanoparticles (figure.2.b). In the absence of mechanical action with determined time the nanoparticles would be suffering from agglomeration (figure2.c) [10] Experimental The aim of the research is: Using AnC technology vibrating bed to obtain economic and technological effectiveness method for syngas production. Figure (3) illustrates scheme of experimental setup for investigation of AnC technology by vibrated bed. Reactor (no. 3 in figure) is a cylindrical apparatus, works in the regime of mixing or milling. It performs reflexiveprogressive motion through a vertical plane in electric furnace (2). The reactor has been designed to vibrate in diapason from 2 to 11 Hz. Reactor has branch pipes for inlet substances, outlet products of reaction, also pouch for thermocouple (11) which connected to control unit(1).
Catalytic system (particles of catalyst and dispersed material) is added to reactor before the experiment starts working. Their motions provide mech-chem activation on catalyst surface. Water feed can be flow by dosator [9] or evaporator [10] or both of them. Particularity of this reactor is a filter [5] which been made from metal or specific net in order to retain the particles of catalyst and dispersed material. Thereby, the quantity of catalyst stays without changing after experiment.
By permanent vibration on the surface of catalyst, it would expose to mechanical influence of inert vibrated material. It is dispersed, arisen defect of structure, is changed properties of surface which determines its activity. In the reactor is added 0.0001 gm of catalyst

Analysis of SMR products
Chromatographer is used for products of SMR with chromatographic column filled with zeolite 5A. The conditions of chromatographic analysis to determine CH 4 , CO, CO 2 , and hydrogen are shown in Table ( The other parameters of chromatographic analysis could be determined in the preliminary calibration of chromatographer.  As its been shown in    and 11 using temperature 600 and 650 qC.

Conclusions
The research has shown the possibility to Apply the aerosol nanocatalysis vibrated bed as alternative technology in Methane steam reforming and it could be effective at 650 qC. Its very flexible to use the experimental setup and parameters changing such as temperature, vibration, volume rate…etc. NiO catalyst is an effective catalyst of methane steam reforming using AnC.