Fixed-bed gasifiers

The Lurgi fixed-bed gasifier operates using lump coal of a noncaking type with an ash composition chosen to avoid a sticky, partly fused ash in the reactor. A slagging version of this gasifier has been tested in Westfield, Scotland. Other fixed-bed gasifiers have similar coal requirements. 

METC A coal gasification process based on a stirred, fixed-bed gasifier. Developed for the U.S. Department of Energy. 

Schwarze Pumpe, Germany 40 MW Noell KRC (7 fixed-bed gasifiers) Commissioned on syngas September 1996 power/methanol... 

Fixed bed gasifiers are generally used for small-scale operation with gas engines, having an electrical output of about 80-500 kWe. They divide into updraft and downdraft gasifiers. 

Midilli, A., Dogru, M., Akay, G., Howarth, C.R. 2002. Hydrogen production from sewage sludge via a fixed bed gasifier product gas. Int J Hydrogen Energy 27 1035-1041. 

British Gas / Lurgi Berkshire, England Fixed Bed Gasifier... 

Figure 2. Differentiation between liquefaction and gasification by-product waters by pH and redox potential characteristics 1 and 2, waste water PETC coal liquefaction development unit, disposable catalyst, runs DCD 13B and DCD 12 3, waste water, SRC-1 plant 4, scrubber water, light oil, Blacksville No. 2 coal 5, waste water, fixed-bed gasifier, METC 6, waste water, fluidized-bed gasifier, Rosebud coal, PETC 7, gasifier condensate, 40 atm Nt, catalyst-impregnated Illinois 6 coal 8, gasifier condensate, 40 atm He, Montana Rosebud coal.

The Fischer-Tropsch synthesis of hydrocarbons is used on a large scale for fuel production in South Africa [78, 79]. Synthesis gas generated from coal in Lurgi fixed-bed gasifiers enters the Synthol reactor (Fig 18), where it is reacted over an iron catalyst at 340°C. The reactor works on the principle of the circulating fluidized bed. The mean porosity in the riser is 85%, and the gas velocity varies between 3 and 12ms1 [2]. Reaction heat is removed by way of heat-exchanger tube bundles placed inside the riser. 

Brief Process Description. Suitably sized wood blocks are fed to a fixed bed gasifier operating essentially at atmospheric pressure. The gasifier is fired with pure oxygen at a rate of about 0.4 tons/ton of methanol product. After heat recovery, the gas is blown through a Lymn washer where the tar and water soluble organics and salts are removed by countercurrent contact with water. 

Excellent solids/gas contact Lower residence time than fixed bed gasifier... 

SVZ (Sekundarrohstoff Verwertungszentrum Schwarze Pumpe) is a centre for the re-nse of secondary raw material. This plant consists of seven downdraft fixed-bed gasifiers and two entrained flow reactors [73]... 

Jae Ik Na, So Jin Park, and Yong Koo Kim, Characteristics of oxygen-blown gasification for combustible waste in a fixed-bed gasifier. Applied Energy, 75, 275-285 (2003). 

Coal may be gasified in situ, i.e. before extraction. If the coal has already been mined, the traditional methods include the Lurgi fixed-bed gasifier (providing gas under pressure from non-caking coal at a conversion efficiency as low as 55%) and the Koppers-Totzek gasifier (oxygen input, gas at... 

The aim of this project is to construct mathematical models for char conversion in a fixed-bed gasifier. The understanding of the conditions during char gasification will facilitate a better control, design and the scaling up of gasification plants. 

In the ongoing project on secondary biomass reactions in fixed-bed gasifiers the following issues will be pursued in the near future ... 

In April 1997 an EC-project started aimed at the development of a novel type of gasifier. The starting point for this development was an analysis of conventional, air-blown fixed-bed gasifiers. Important (technical and/or economic) disadvantages of these gasifiers were identified like ... 

State-of-the-art fixed bed gasifiers are thermally optimised such that the outlet temperature is in the range of 400 C, i.e. considerably lower than the adiabatic temperature of the gasification process itself Conventional fixed bed gasificers must... 

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