Coal primary

Production curves of A1 well (Fig. 3) indicate there is no fine and gas flow during the early steady depressurization process. After drop of 65 m in PEL, A1 well commences to produce gas on the 125th drainage day. And gas rate increases with no fine flow under the steady PEL. The main reasons for no fine flow of A1 well are a) coal primary texture is intact because of the simple structure nearby, and accordingly there is few coal fine (Fig. 2(a)) b) the pressure drop induced by steady PEL is too small to broke coal texture, accordingly there is no fine produced and no influence on productivity of this well. 

Figure 15. NO and N2O emissions versus recycle ratio for El-Cerrejon and Illawara coal Primary air ratio = 1.2 = 825°C ...

Benzene was prepared from coal tar by August W von Hofmann m 1845 Coal tar remained the primary source for the industrial production of benzene for many years until petroleum based technologies became competitive about 1950 Current production IS about 6 million tons per year m the United States A substantial portion of this ben zene is converted to styrene for use m the preparation of polystyrene plastics and films... 

Most coal-tar chemicals are recovered from coproduct coke ovens. Since the primary product of the ovens is metallurgical coke, production of coal chemicals from this source is highly dependent on the level of activity in the steel industry. In past years most large coke producers operated thein own coproduct recovery processes. Because of the decline in the domestic steel industry, the recent trend is for independent refiners to coUect cmde coal tars and light oils from several producers and then separate the marketable products. 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

A variation to the top-feed dmm filter is the dual dmm filter which uses two dmms of the same size in contact with each other and rotating in opposite directions. The feed enters into the V-shaped space formed on top of the two dmms and the cake that starts forming initially contains coarser particles due to the settling which takes place in the feed zone. This is beneficial to the clarity of the filtrate because the coarser particles act as a precoat. Erom the point of view, however, of the final moisture content of the cake the stratification of the soHds in the cake may lead to somewhat wetter cakes. Utilization of the area of the dmms is poor since there are dead spaces under the two dmms. The primary appHcation of the dual dmm filters is in dewatering coarse mineral or coal suspensions at feed concentrations greater than 200 kg/m. ... 

The chemical characteristics of biomass vary over a broad range because of the many different types of species. Table 8 compares the typical analyses and energy contents of land- and water-based biomass, ie, wood, grass, kelp, and water hyacinth, and waste biomass, ie, manure, urban refuse, and primary sewage sludge, with those of cellulose, peat, and bituminous coal. Pure cellulose, a representative primary photosynthetic product, has a carbon content of... 

Analysis Pure ceUulos e Pine wood Kentuck y bluegrass Giant brown kelp Feedlo t manur e Urban refuse Primary sewage sludge Reed sedge peat Illinois bituminous coal... 

The main difference between gas works and coke oven practice is that, in a gas works, maximum gas yield is a primary consideration whereas in the coke works the quality of the coke is the first consideration. These effects are obtained by choice of a coal feedstock that is suitable to the task. For example, use of lower volatile coals in coke ovens, compared to coals used in gas works, produces lower yields of gas when operating at the same temperatures. In addition, the choice of heating (carbonizing) conditions and the type of retort also play a principal role (10,35). 

Chemical Regeneration. In most MHD system designs the gas exiting the toppiag cycle exhausts either iato a radiant boiler and is used to raise steam, or it exhausts iato a direct-fired air heater and is used to preheat the primary combustion air. An alternative use of the exhaust gas is for chemical regeneration, ia which the exhaust gases are used to process the fuel from its as-received form iato a more beaeftcial oae. Chemical regeaeratioa has beea proposed for use with aatural gas and oil as well as with coal (14) (see Gas, natural Petroleum). 

Primary fuel for each plant is pulverized Illinois No. 6 coal. 

The functional group ia collectors for nonsulfide minerals is characterized by the presence of either a N (amines) or an O (carboxyUc acids, sulfonates, etc) as the donor atoms. In addition to these, straight hydrocarbons, such as fuel oil, diesel, kerosene, etc, are also used extensively either as auxiUary or secondary collectors, or as primary collectors for coal and molybdenite flotation. The chain length of the hydrocarbon group is generally short (2—8 C) for the sulfide collectors, and long (10—20 C) for nonsulfide collectors, because sulfides are generally more hydrophobic than most nonsulfide minerals (10). 

Between 1930 and 1950, the primary emphasis of ammonia process development was ia the area of synthesis gas generation (3) (see Fuels, SYNTHETIC, GASEOUS FUELs). Extensive coal deposits ia Europe provided the feedstock for the ammonia iadustry. The North American ammonia iadustry was based primarily on abundant suppHes of low cost natural gas (see Gas, natural). 

CPA. Copolymer alloy membranes (CPAs) are made by alloying high molecular weight polymeries, plasticizers, special stabilizers, biocides, and antioxidants with poly(vinyl chloride) (PVC). The membrane is typically reinforced with polyester and comes in finished thicknesses of 0.75—1.5 mm and widths of 1.5—1.8 m. The primary installation method is mechanically fastened, but some fully adhered systems are also possible. The CPA membranes can exhibit long-term flexibiHty by alleviating migration of the polymeric plasticizers, and are chemically resistant and compatible with many oils and greases, animal fats, asphalt, and coal-tar pitch. The physical characteristics of a CPA membrane have been described (15). 

---