Gasifier Winkler

The Winkler gasifier (Fig. 5) is an example of a medium heat-value gas producer which, when oxygen is employed, yields a gas product composed mainly of carbon monoxide and hydrogen (43). 

None of these current processes has a distinct advantage over the other two in all situations of coal gasification. However, we believe that the Winkler is best suited for the production of methanol because it yields a clean gas with a low inerts content. Other advantages include the plant s low environmental impact, the minimal coal preparation required and the simple construction of the Winkler gasifier. 

The H S containing stream from the acid gas removal unit is sent to the sulfur recovery unit to produce molten sulfur. Figure 6 is a typical process flow diagram of synthesis gas production for methanol via coal gasificiation by the Winkler gasifier. 

The classic Winkler gasifier, which operates at atmospheric pressure, is today still in use in some smaller plants (e.g., in China). In a further development (HTW process) by Rheinbraun it has been tested in a demonstration plant with lignite at 10 bar [586], [587]. 

The first application of the fluidized-bed gasifier in the gasification process is the original Winkler process. In the Winkler process, steam and air (or 02) are used at atmospheric pressure. The schematic of a typical Winkler gasifier is shown in Figure 4.25. The coal (brown coal coke, subbituminous, or bituminous coals) is... 

If the bed is loosened as the gas flow rate increases and becomes turbulent when the minimum fluidizing velocity is exceeded, the system is called fluidized-bed gasification. This principle is used in Winkler gasifiers. 

At present, three classical Winkler gasifiers are still operating throughout the world no new ones have been built for the past 25 years. The only commercial HTW gasifier so far was conceived as a demonstration plant for a coal throughput of approximately 30l/h and has been operating for several years now. The gas is used to produce methanol. Its coal throughput meets the demand of a 400 tpd methanol plant. Another HTW plant of the same size is currently under construction. 

The Winkler gasifier is widely used to make producer gas for industrial and domestic use, but few have been... 

Legend I SI-1 Coal bln SF-S Feeder R-3 Winkler gasifier E-4 Utility boiler E-5 Preheater S-6 Multi eye Lone E-7 Final cooler B-8 D I s i niegrator S-9 Mist e I In nator... 

As many as 70 Winkler gasifiers in more than 20 plants were constructed and in operation at one time (15). However, only two plants are known to still have operating Winkler gasifiers. Although the latest gasifiers were built in 1960-62 at the Neyveli Works in India (Neyveli Lignite Corporation), those units were decommissioned in 1981. 

In addition to operating at atmospheric pressure, the conventional Winkler gasifier has two other critical drawbacks. First, it uses only coals with high reactivity, such as brown coals or lignites. Second, it achieves relatively low carbon conversion, even with high-reactivity coals, and raises the problem of how to use the char it produces. 

Winkler Union Kraffstoff atmospheric Winkler gasifier (for comparison)... 

Figure 9.5 Reh diagram with gasifier opera- e-line - entrainment line, f-line - fluidization tion points for South African coal (30 bar) and line, FBDB - fixed-bed dry bottom, HTW -varied ash content for the internal circulation high-temperature Winkler), gasifier (INCI) concept (BGL - British Gas/Lurgi,...

Table 17.11 summarizes the characteristics of several fluidized-bed gasifiers presently under development, as well as the Winkler gasifier, which is commercially available. There are several Winkler gasifiers at various installations worldwide, and the largest unit processes 650 tons of coal/day. The Winkler gasifier is illustrated in Fig. 17.16. 

Fig. 17.16. A Winkler gasifier. "Comparative Study of Coat Gasificatiort Processes—Koppers-Totzek, Lurgi artd Winkler," Koppers Co., Pittsburgh, PA.)...

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