Hydrogen gas is widely used in many industrial applications such as the production of ammonia and some fossil fuels refining steps. This paper discusses the most common process currently used for the production of hydrogen from natural gas; steam reforming method. The method involves four sub-processes. The first sub-process is dehydrosulfurization which purifies the natural gas from sulfur contaminants. The second sub-process is steam methane reforming (SMR) which converts natural gas and steam to hydrogen. The third sub-process is the medium temperature shift (MTS) which converts carbon monoxide and steam to carbon dioxide and hydrogen. The last sub-process is the Pressure Swing Adsorption (PSA) which purifies the produced hydrogen gas. Low cost and energy efficiency of the process is one of its main advantages and the reason for its industrial popularity. The disadvantages of the process are the use of non-renewable raw materials and production of carbon dioxide which is a primary cause of global warming. Current and future advancements in the process include using new catalysts to minimize the cost of the entire process, and implementing carbon capture and storage techniques to reduce the negative environmental impact of carbon dioxide produced.
Keywords: Hydrogen gas, Steam reforming, Dehydrosulfurization, Steam methane reforming, Medium temperature shift, Pressure swing adsorption, Carbon capture, Carbon storage.
1. Introduction
Hydrogen demand is already high and it is expected to considerably increase in the next few years due to the refinery industry's growing needs and new applications such as synthetic fuel or biofuel production. In 2004, the total global hydrogen gas production was equal to about 50 million metric t...
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...es, the hydrogen sulfide goes through Claus process to produce elemental sulfur but this process is not described in details because it is outside the scope of this paper.6
3.2. Steam Methane Reforming (SMR)
SMR is the most important sub-process which gives the whole production process of hydrogen gas its current name. SMR is the reaction that converts purified natural gas and steam into carbon monoxide and hydrogen. The reaction for steam reforming is shown below.5
CH_4+ H_2 O →CO+3 H_2 (3)
The above reaction is endothermic under standard conditions (∆〖H^o〗_298=206 kJ/mol), which means that the reaction is not thermodynamically favorable and the reaction equilibrium lies towards the reactants side. Therefore, the conditions of the reaction are altered so that the equilibrium constant moves towards the product side to achieve higher conversion percentages.5
In the production process of chemicals it requires to use of a average calorific value gas (MCV) also non-nitrogen diluted by minor impurities for best alteration to chemical compounds (Paisley et al., 1994). For the electricity production the used product gas should be clean from char-particles, pitch and ash etc. before it is inserted into the gas turbine or in a combustion engine. The higher temperature gases which exits from the gas turbine can be further used to generate steam from there heat for a steam turbine, like as an Integrate Gasification Combined Cycle (IGCC) generally used in power
Elements are the basic building blocks of matter due to the fact that they are chemically the simplest substances. Whether we can find them in the air or in our gold/silver necklaces, elements are everywhere! One essential element is hydrogen, the first element on the period table (located under Group 1 as an alkaline metal) is composed of a single proton and electron; therefore having an atomic number and atomic mass of 1 and electron configuration of 1s1. In fact, hydrogen is the lightest, simplest and most commonly found chemical element in the universe (it makes up about 90% of the universe by weight). Interestingly enough, the heavier elements on the periodic table were either made from hydrogen or other elements that were made from hydrogen. The most common isotope formed of hydrogen is protium, with 1 proton and no neutrons. Hydrogen can also exist as both positively or negatively charged. The physical form of hydrogen at room temperature is a colorless and odorless gas. Hydrogen gas is extremely flammable and because of this chemical property, it is used as fuel for the main engine of space shuttles. Hydrogen is an important element and has received a lot of recognition throughout history for its usefulness.
Syngas through water gas-shift reactions relate multiple reasoning to the foundation and production of several oil and gas related industries. The following analysis of syngas will begin with the explanation of water gas-shift reaction along with related Steam Reform Reactor, and Fischer-Tropsch processes. In the major bulk of the analysis, the complete process of syngas involvement with water gas-shift reactions will be discussed. In addition, catalyst involvement will be introduced in processing techniques. In reference to processing, the explanation will delve into effects from high and low temperature shift catalyst and their compositions. In respect to industrial settings, major examples of the process will also be discussed, which includes production of syngas through multiple uses. A brief explanation in terms of economics, alternate uses, and ecological effects will also be discussed through reverence of syngas through water gas-shift reactions.
In able to produce ammonia, nitrogen and hydrogen gas mixture composed together under high temperature, high pressure conditions and the role of catalyst. In the spirit of perseverance, through continuous experiments and calculations, Haber finally achieved encouraging results in 1909. When the temperature is 600 degree Celsius, under the conditions of 200 atmospheric pressure and osmium catalyst, the yield was approximately 8% of ammonia. 8% conversion rate is not considered high; it will obviously affect economic production. Haber known ammonia production cannot attain high conversion rate like sulfuric acid. Haber cons...
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In nature hydrogen is always found combined with other elements, which means it has to be manually made by passing an electric current through water to form hydrogen and oxygen. There is a tremendous amount of energy involved in splitting the molecules to free the hydrogen from its captor. The current method of producing hydrogen from water is through the use of oil and coal. Oil and coal are the two main resources the world is trying to cut back on. The main purpose of using hydrogen is lost when considering the actual manufacturing process of hydrogen contributes a significant amount of carbon dioxide. When the big coal and oil companies start investing their profits in hydrogen, something has gone awry. Each company sees its future limited and wants to ensure their survival. Since they have the most money they will be the main producer of hydrogen. The hydrogen economy will benefit the mining and oil industry at the cost of the clean-energy dream.
...e is of the same sort as the exhaust temperature. Alteration of liquid hydrocarbons into gas must develop the burning process. Several doubts still stay on the expenses and the technical capability of the catalytic cracking process. If a division unit is necessary to separate the unreached part of the product stream from the gaseous hydrocarbons, the system will turn out to be more expensive. Though, if vaporization suffices, no additional apparatus will be needed.
The Olefins II Unit makes hydrocarbons from naphtha or natural gas using furnaces. After distillation, the p...
converted into ethanol biochemically, but is easy to do thermochemically. The optimal biomasses for thermochemical conversions are trees and mill products. These have a high lignin concentration, so these biomass products respond better to the thermochemical method of ethanol production (Theis, 2007). Figure 3 shows the thermochemical process. The first step is drying the plants. Next the plants are burned into synthesis gas, or syngas. The syngas is made of carbon monoxide (CO) and hydrogen (H2). This is called gasification. The gasification produces tar and sulfur, which is not clean and interferes with the making of ethanol. As a result, the syngas is sent to a tar reformer (Nasr, n.d., Theis, 2007). The tar reformer uses enzymes to convert about 97% of the tar into syngas (Theis, 2007). Then, the syngas is cleaned to get purer CO and H2 gasses. Next, the gas is compressed and mixed with a metal catalyst. The catalyst builds the gas back up into ethanol (Nasr, n.d.). There are some drawbacks to the thermochemical process, however. The catalysts used in the tar reformer are very expensive and the tar remains accumulate. Biorefineries could utilize
Humans use more and more energy each year and currently Australia depends heavily on coal, a finite resource. The energy crisis is a big concern for the world as countries begin to research alternative and new energy sources. Development of an energy source that is abundant and environmentalists friendly is essential for economic development and sustainability. The recent research into the use of methane from methane clathrates highlights this as a potential future energy source around the world. However, our group strongly suggests that Australia does not investigate methane clathrate as a source of energy in Australia due to its extensive disadvantages.
Hydrogen would be one of the easiest sources of renewable energy to incorporate into our current energy infrastructure. Since hydrogen is a gas of normal temperature, it is possible to have it be used as a fuel in vehicles similar to current ones. For example, Hydrogen could be introduced into the vehicle as a gas, stored...
Biomass gasification is a process by which biofuel is produced. It has been used for over 180 years but in the last decades it has been reconsidered as an interesting technique due to the fact that oil supplies are decreasing. As mentioned before, gasification is a thermal process. Heat is added up in order to convert the organic mass to biofuel. The biomass usually undergoes drying, pyrolysis, partial oxidation and reduction. Nowadays the configurations used for gasification are three: fixed bed gasifier, fluidized bed gasifier and entrained bed gasifiers. The simplest configuration is the
...aus method by reacting the hydrogen sulfide with air, called the thermal step. Then creating a reaction with sulfur dioxide produced from the thermal step to recover more sulfur, this is known as the catalytic step. From here the sulfur produced can be used for many real world applications: production of sulfuric acid, processing of sulfur in fertilizers, and sulfur-sodium batteries. Although there are plenty more
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