Direct conversion of natural gas to higher hydrocarbons: A review

Chemical conversion of carbon dioxide (CO2) to methanol has the potential to address two relevant sustainability issues: economically feasible replacement of fossil raw materials and avoidance of greenhouse gas emissions. However, chemical stability of CO2 is a challenging impediment to conversion, requiring harsh reaction conditions at the expense of increased energy input, adding capital, operational and environmental costs. This work evaluates two innovative chemical conversion of CO2 to methanol: the indirect conversion, which uses synthesis gas produced by bi-reforming as intermediate, and the direct conversion, via hydrogenation. Process simulations are used to obtain mass and energy balances, needed to support economic analyses. Due to the uncertainties in the raw material prices, including CO2 and hydrogen (H2), its limits for economic viability are estimated and sensitivity analyzes are carried in predetermined prices (base cases). It is considered the scenario of free CO2 available in atmospheric conditions, as in a bioethanol industry, but the sensitivity analyses show the results for other scenarios, as in a CO2 rich natural gas, in which the cost of processing CO2 is zero. The economic analyses show that hydrogenation can be feasible if hydrogen prices are lower than 1000 US$/t, while the indirect route is viable only for cheap sources of natural gas below 3.7 US$/MMBtu. The CO2 pre-treatment costs are not as sensible as the others raw materials.

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An Experimental Ignition Delay Study of Alkane Mixtures in Turbulent Flows at Elevated Pressure and Intermediate Temperatures

Volume 2: Combustion, Fuels and Emissions, Parts A and B ◽

10.1115/gt2010-22865 ◽

2010 ◽

Author(s):

David Beerer ◽

Vincent McDonell ◽

Scott Samuelsen ◽

Leonard Angello

Keyword(s):

Natural Gas ◽

Turbulent Flows ◽

Ignition Delay ◽

Flow Reactor ◽

Elevated Pressure ◽

Ternary Mixtures ◽

Turbine Engine ◽

Binary And Ternary Mixtures ◽

Delay Times ◽

Higher Hydrocarbons

Autoignition delay times of mixtures of alkanes and natural gas were studied experimentally in a high pressure and intermediate temperature turbulent flow reactor. Measurements were made at pressures between 7 and 15 atm and temperatures from 785 to 935K. The blends include binary and ternary mixtures of methane, ethane and propane; along with various natural gas blends. Based on these data, the effect of higher hydrocarbons on the ignition delay time of natural gas type fuels at actual gas turbine engine conditions has been quantified. While the addition of higher hydrocarbons in quantities of up to 30% were found to reduce the ignition delay by up to a factor of four, the delay times were still found to be greater than 60 milliseconds in all cases which is well above the residence times of most engine premixers. The data were used to develop simple Arrhenius type correlations as a function of temperature, pressure and fuel composition for design use.

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Direct Convertion Of Methane To Liquid Hydrocarbons Using HZSM-5 Zeolite Catalyst Loaded With Metal

REAKTOR ◽

10.14710/reaktor.7.1.7-12 ◽

2017 ◽

Vol 7 (1) ◽

pp. 7

Author(s):

D. D. Anggoro

Keyword(s):

Natural Gas ◽

Packed Bed ◽

Direct Conversion ◽

Single Step ◽

Packed Bed Reactor ◽

Impregnation Method ◽

Liquid Hydrocarbons ◽

Oxidation Of Methane ◽

Conversion Of Methane ◽

Main Component

Methane is the main component of natural gas and this research provides the platrorm on the potential of utilizing natural gas, found abundant in Indonesia, to form gasoline. The objectives of the research are to modify HZSM-5 zeolite with a series of transition metals (Cr, Mn, Co, Ni, Cu, and Pt) and Ga , and to evaluate the performances of these catalyst for the single step conversion of methane to gasoline. The oxidation of methane were carried out in a micro-packed bed reactor at atmoepheric pressure, temperature 800 0C, F/W = 10440 ml/g.hr and 9%vol O2. Metals were loaded into the HZSM-5 zeolite by the wetness incipient impregnation method. The characterization results indicated that the ionic metals (Mn+) occupy the H+ position of HZSM-5 and metal loaded HZSM-5. Ni- HZSM-5, Cu- HZSM-5 and Ga- HZSM-5 gave a high methane conversion and high gasoline selectivity. Among the catalyst samles tested, Cr- HZSM-5 showed the highest Research Octane Number (RON=86). These catalyst have the potential to convert natural gas to C5+ liquid hydrocarbons provided the oxidation, dehydration and oligomerization function of the metals are in balance.Keywords : direct conversion, methane, liquid hydrocarbons, metal, HZSM-5

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