Industrial coal liquefaction processes

The medium-speed diesel (railroad locomotive, marine engines) appears to be another potential application for SRC-II coal liquids to displace petroleum fuels. Other applications being studied by potential users include the automotive turbine, reheat furnace fuel in the steel industry and reformer feedstock for fuel cells. All in all, the products to be derived from coal liquefaction processes like SRC-II can, over time, displace a portion of our requirements for imported petroleum in a variety of end uses. 

NEDOL [New Energy Development Organization Liquefaction] A coal liquefaction process in development in Japan by the New Energy and Industrial Technology Development Organization (NEDO), Tokyo. Crushed coal is mixed with a pyrite catalyst and slurried in a hydrogenated heavy oil. Liquefaction takes place at 450°C, 170 bar. The overall oil yield is 59%. The used solvent is hydrogenated and recycled. Piloted in Kashima, Japan, in 1997 to 1998. Two Chinese companies were licensed to build test units in 2006. 

The first direct coal liquefaction process was developed and patented by Bergius from Germany in 1913 and, therefore, is often referred to as the Bergius process. The world s first industrial-scale direct coal liquefaction plant was built in Leuna, Germany, in 1927 with an annual fuel production of 10,0001. By 1939, Germany built 12 direct coal liquefaction plants with a combined annual fuel production of about 4.23 million metric tons, which supplied about 70% of the aviation fuel and 50% of the transportation fuel for German troops during World War II. 

One of the most widely-used three-phase reactors is the trickle-hed reactor which is particularly favored hy the hydroprocessing industry. On the contrary, slurry systems are prefered in the chemical industry they are used in direct coal liquefaction processes and in Fischer-Tropsch synthesis. 

Imperial Chemical Industries (ICI) operated a coal hydrogenation plant at a pressure of 20 MPa (2900 psi) and a temperature of 400—500°C to produce Hquid hydrocarbon fuel from 1935 to the outbreak of World War II. As many as 12 such plants operated in Germany during World War II to make the country less dependent on petroleum from natural sources but the process was discontinued when hostihties ceased (see Coal conversion PROCESSES,liquefaction). Currentiy the Fisher-Tropsch process is being used at the Sasol plants in South Africa to convert synthesis gas into largely ahphatic hydrocarbons at 10—20 MPa and about 400°C to supply 70% of the fuel needed for transportation. 

The best-known processes are the IGOR (Germany), HTI (America), and NEDOL (Japan). The New Energy and Industrial Technology Development Organization (NEDO) finished a 1501 coal per day coal liquefaction pilot plant in 1998. Shenhua Group Corporation is building a 40001 coal per day (1 Mt oil/year) commercial plant in China. 

We believe that the PFGC equation of state approach will be the most fruitful new route to predicting phase behavior of the diverse systems encountered in the natural gas/petroleum/coal liquefaction gasification process industry. We commend it to your attention. 

Hydrogen sulfide is a by-product of many industrial operations, eg, coking and the hydrodesulfurization of crude oil and of coal. Hydrodesulfurization is increasing in importance as the use of high sulfur crude oil becomes increasingly necessary (see Petroleum, refinery processes). A large future source of hydrogen sulfide may result if coal liquefaction attains commercial importance (see Coal CONVERSION processes). 

Many of the feedstocks for the chemical industry, especially aromatic hydrocarbons, were originally obtained as by-products from the carbonization of coal. (1,2) However, nowadays, most of these chemical feedstocks are derived from petroleum. Nevertheless, it is probable that, within the next few decades, the shortage of world reserves of petroleum will mean that BTX will once again have to be produced from coal, as will ethylene. It is, therefore, appropriate to examine ways in which these materials can be produced from coal the present investigation was designed to study the formation of BTX and ethylene by the thermal cracking of coal-derived materials from the NCB coal liquefaction/hydrogenation processes. (3)... 

Gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are widely used in the chemical and petrochemical industries for processes such as methanol synthesis, coal liquefaction, Fischer-Tropsch synthesis and separation methods such as solvent extraction and particle/gas flotation. The hydrodynamic behavior of gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are of great importance for the design and scale-up of reactors. Although the hydrodynamics of the bubble and slurry bubble columns has been a subject of intensive research through experiments and computations, the flow structure quantification of complex multi-phase flows are still not well understood, especially in the three-dimensional region. In bubble and slurry bubble columns, the presence of gas bubbles plays an important role to induce appreciable liquid/solids mixing as well as mass transfer. The flows within these systems are divided into two... 

There is a wide support in the utility industry for the development of a number of liquefaction processes. In this way the probability of technical success for the overall objective is enhanced. Another benefit which is not so apparent is the avoidance on development of a single process which may not be applicabel to a wide variety of commercially important coals. 

What, then, does the future hold This author believes that the catalytic hydrocarbonization/gasification concept will ultimately achieve commercial success for the production of liquid and gaseous fuels from coal. In selected applications, the mild hydrocarbonization of western coal to produce liquid and gaseous fuels with power generation from the low-sulfur char may also be commercially attractive. Finally, further development of the flash hydropyrolysis technology, as exemplified by the Rocketdyne project, may eventually lead to a technically and economically attractive liquefaction process. But the most important questions still remain unanswered. Does private industry have sufficient interest to pursue the possibilities Where is the interest focused Will a private consortium build a hydrocarbonization/ cogeneration complex using western coal Will the phoenix arise from the ashes ... 

Reactions involving gas, liquid, and solid are often encountered in the chemical process industry. The most common occurrence of this type of reaction is in hydroprocessing operations, in which a variety of reactions between hydrogen, an oil phase, and a catalyst have been examined. Other common three-phase catalytic reactions are oxidation and hydration reactions. Some three-phase reactions, such as coal liquefaction, involve a solid reactant. These and numerous other similar gas-liquid solid reactions, as well as a large number of gas-liquid reactions, are carried out in a vessel or a reactor which contains all three phases simultaneously. The subject of this monograph is the design of such gas-liquid -solid reactors. 

The 1973 petroleum crisis intensified research on coal liquefaction and conversion processes. The technology developed in this field was later harnessed in chemical recycling of plastics. Mastral et al. [32], for example, employed two different batch reaction systems (tubing bomb reactors and magnetically stirred autoclave) and a continuous reactor (swept fixed bed reactor). Chemical recycling techniques such as pyrolysis [28, 33-38] or coliquefaction with coal [39, 40] convert plastic wastes into hydrocarbons that are valuable industrial raw materials. 

Over 70% of known catalytic reactions involve some form of metallic component. Industrially, metals are used in catalytic reforming, hydrocracking, ammonia and methanol synthesis, indirect coal liquefaction, oxidation, and a vast number of organic hydrogenation and dehydrogenation processes. Academically, metals are favored for research since they are easily prepared in pure form and conveniently characterized. In fact, most of the fundamental information leading to conceptual theories in catalysis originated with studies on metal systems. 

The ORC flash pyrolysis process has been used with minor modifications to process municipal and industrial solid wastes. The emphasis is on liquid yield. More preparation of the feed is involved than for coal gasificaltion or coal liquefaction. A process schematic is shown in Figure 3. In addition to grinding and drying, an air classification process and screening are used... 

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