THE DYNAMIC BEHAVIOR OF A FIXED-BED STEAM-OXYGEN COAL GASIFIER DISTURBED BY WATER INFLUX II. MODEL DEVELOPMENT AND VERIFICATION

This paper describes the experiences leading to successful sampling of hot, contaminated, coal-derived gas streams for alkali constituents using advanced spectrometers. This activity was integrated with a multi-phase, combustion test program which addressed the use of minimally treated, coal-derived fuel gas in gas turbines. Alkali contaminants in coal-derived fuels are a source of concern, as they may induce corrosion of and deposition on turbine components. Real-time measurement of alkali concentrations in gasifier output fuel gas streams is important in evaluating these effects on turbine performance. An automated, dual-channel, flame atomic emission spectrometer was used to obtain on-line measurements of total sodium and potassium mass loadings (vapors and particles) in two process streams at the General Electric fixed-bed coal gasifier and turbine combustor simulator facility in Schenectady, New York. Alkali measurements were taken on (1) slipstreams of high temperature, high pressure, minimally clean, low-Btu fuel gas containing entrained particles from the gasifier and (2) a slipstream of the exhaust gas from the combustor/turbine simulator. Alkali detection limits for the analyzer were found to be on the order of one part per billion. Providing a representative sample to the alkali analyzer at the limited flows required by the instrument was a major challenge of this activity. Several approaches and sampling hardware configurations were utilized with varying degrees of success during this testing campaign. The resulting information formed the basis for a second generation sampling system which has recently been successfully utilized to measure alkali concentrations in slipstreams from the described fixed-bed coal gasifier and turbine combustor simulator.

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Dynamics of Bed for Regeneration of Cerium Oxide High-Temperature Coal Gas Desulfurization Sorbent

Materials Science Forum ◽

10.4028/www.scientific.net/msf.896.148 ◽

2017 ◽

Vol 896 ◽

pp. 148-154

Author(s):

Jun Ming Yu ◽

Shang Guan Ju ◽

Li Ping Liu ◽

Lei Yang ◽

Jia An ◽

...

Keyword(s):

High Temperature ◽

Cerium Oxide ◽

Dynamic Behavior ◽

Sulfur Content ◽

Fixed Bed ◽

Movement Speed ◽

Coal Gas ◽

Oxygen Analyzer ◽

Micro Reactor ◽

High Temperature Gas

The dynamic behavior of bed for regeneration of cerium oxide high temperature gas desulfurization sorbent under the atmosphere of O2 was investigated in the fixed bed micro-reactor. O2 concentration during the regeneration can be detected by an oxygen analyzer, and the sulfur content of sorbent in the bed was test using sulfur analyzer. The effects of O2 concentration, regeneration temperature on the dynamic behavior of bed for regeneration of CeO2 desulfurization sorbent were discussed. According to the experimental results, the length and movement speed of regeneration zone are calculated. The results showed that the increase of O2 concentration in inlet gas obviously improves the movement speed of regeneration zone in bed for CeO2 desulfurization sorbent, and the increase of regeneration temperature can decreased the length of the regeneration zone and improved the movement speed of the regeneration zone. The increase of regeneration temperature had a better effect on the improvement of bed utilization of sorbent than that of O2 concentration.

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00/02379 Steady-state and dynamic behavior of the fixed-bed catalytic reactor for Fischer—Tropsch synthesis

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(00)96292-1 ◽

2000 ◽

Vol 41 (5) ◽

pp. 270

Keyword(s):

Steady State ◽

Dynamic Behavior ◽

Fixed Bed ◽

Tropsch Synthesis ◽

Catalytic Reactor ◽

Fischer Tropsch ◽

Fischer Tropsch Synthesis

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Dynamic Simulation of Adiabatic Catalytic Fixed-Bed Tubular Reactors: A Simple Approximate Modeling Approach

ASEAN Journal of Chemical Engineering ◽

10.22146/ajche.49713 ◽

2014 ◽

Vol 14 (1) ◽

pp. 25

Author(s):

Wiwut Tanthapanichakoon ◽

Shinichi Koda ◽

Burin Khemthong

Keyword(s):

Dynamic Model ◽

Dynamic Behavior ◽

Dynamic Simulation ◽

Flow Rate ◽

Fixed Bed ◽

Axial Dispersion ◽

Fixed Bed Reactor ◽

Inlet Temperature ◽

Acetylene Hydrogenation ◽

Tubular Reactors

Fixed-bed tubular reactors are used widely in chemical process industries, for example, selective hydrogenation of acetylene to ethylene in a naphtha cracking plant. A dynamic model is required when the effect of large fluctuations with time in influent stream (temperature, pressure, flow rate, and/or composition) on the reactor performance is to be investigated or automatically controlled. To predict approximate dynamic behavior of adiabatic selective acetylene hydrogenation reactors, we proposed a simple 1-dimensional model based on residence time distribution (RTD) effect to represent the cases of plug flow without/with axial dispersion. By modeling the nonideal flow regimes as a number of CSTRs (completely stirred tank reactors) in series to give not only equivalent RTD effect but also theoretically the same dynamic behavior in the case of isothermal first-order reactions, the obtained simple dynamic model consists of a set of nonlinear ODEs (ordinary differential equations), which can simultaneously be integrated using Excel VBA (Visual BASIC Applications) and 4th-order Runge-Kutta algorithm. The effects of reactor inlet temperature, axial dispersion, and flow rate deviation on the dynamic behavior of the system were investigated. In addition, comparison of the simulated effects of flow rate deviation was made between two industrial-size reactors.Keywords: Dynamic simulation, 1-D model, Adiabatic reactor, Acetylene hydrogenation, Fixed-bed reactor, Axial dispersion effect

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