Production of hydrogen-rich gas from waste rigid polyurethane foam via catalytic steam gasification

Catalytic steam gasification of waste rigid polyurethane foam, in the fixed-bed reactor, was performed to produce hydrogen-rich gas. The influence of nine kinds of additives on the yield of products (gaseous, solid and liquid product) and the volume fraction of hydrogen was investigated. Among the additives, calcium carbonate, as the catalyst, could effectively enhance the gas yield and the volume fraction of hydrogen. A three-factor three-level completely randomised factorial (3 × 3 × 3) design, with calcium carbonate as the catalyst, was applied to investigate the influence of experimental conditions (temperature, steam flowrate and catalyst dosage) on the volume fraction of gaseous product components. The data were processed with SPSS statistical software. The result showed that the main effects of one variable, the interactive effects between two factors and the interactive effects among three factors all have statistical high significance. The best catalysed process is realised when calcium carbonate is the catalyst, gasification temperature is 1100°C, steam flowrate is 0.7 kg h−1, catalyst dosage is 10 wt% of waste rigid polyurethane foam. Under this condition, the volume fraction of hydrogen reaches up to 79.85%.

Hydrogen-Rich Gas Formation Characteristics under Microwave Catalytic Pyrolysis of Sewage Sludge

Microwave catalytic pyrolysis of sewage sludge were conducted on a single mode microwave reactor. The effects of CaO and steam on hydrogen-rich gas formation characteristics were analyzed. The results indicated that the CaO can improve the formation of H2and CO. When CaO in sewage sludge increased from 0 to 0.75 g/(g dried sludge), the H2and CO concentration increased from 62 vol.% to 77 vol.%, while CH4and CO2concentrations decreased from 28 vol.% to 9 vol.%. The steam can also improve the formation of H2and CO, with 1.59 g/min of the steam flowrate, the H2and CO concentration increased to the maximum of 81 vol.%, and the CH4and CO2concentration decreased to the minimum of 16 vol.%. When the steam gasification was coupled with the CaO catalyzing, the H2concentration can reach to 61 vol.%, which was 79.3% higher than the experimental conditions absent of steam and CaO.

Considerations in Converting a Dual Shell or a Dual Pressure Coal Fired Plant Condenser Into a Combined Cycle Plant Condenser

The design of a dual shell or a dual pressure condenser employed in a coal fired plant is different from that in a combined cycle plant. The coal fired plant dual pressure condenser is equipped with feedwater heaters in the condenser neck, extraction piping, an external flash tank and a large number of vents and drains. Dual shell or dual pressure condenser in a combined cycle plant does not include feedwater heaters in the condenser neck and the related extraction piping. There is no external flash tank and the number of vents and drains are minimal. Combined cycle plants have a higher steam flowrate, are required to operate in bypass mode and in certain instances have high make up water flowrate. Apart from the above major differences there are a number of minor differences that must be accounted and addressed when converting a coal fired plant dual shell or dual pressure condenser into a combined cycle plant condenser. This paper highlights the major and minor differences in the design, construction and operation of dual shell or dual pressure condenser operating in a coal fired plants and combined cycle plant. The modifications required to convert the condenser from coal fired application to combined cycle application are discussed. Precautions to be followed in operating the condenser in the new role are addressed.

Ethanol/Moisture Contents in Fermented Grains and their Effects on the Yield and Quality of Chinese Luzhou-Flavor Liquor

The ethanol/moisture contents in fermented grains were measured and systematic experiments were carried out to investigate the optimal operation condition for distillation of Chinese Luzhou-flavor liquor. The results show that from the top surface (0 m depth) of fermentation tank to the bottom (2 m depth), the moisture content in the grains increases linearly from 60.67 wt.% to 70.44 wt.%, while the ethanol content presents a parabolic distribution with maximal content of 6.29 wt.% at 1.5 m depth. It is found that for efficient distillation of fermented grains, there exists an optimal steam flowrate at which the maximum yield of distilled liquor will be achieved. For the grains with given moisture content, the optimal steam flowrate keeps nearly constant with different ethanol contents, while for the grains with given ethanol content, the optimal steam flowrate increases as the moisture content become increased. Combined with the gas chromatography analysis, it is also presented that the distilled liquor obtained from the grains with higher ethanol content and/or lower moisture content will contain higher concentration of alcohol-soluble flavor compounds, so that the distilled liquor has better quality. The findings in this study provide important reference for the optimization of distillation process of Chinese Luzhou-flavor liquor.

Wet Steam Flowrate Calibration Facility

Newly developed wet steam flowrate calibration facility is introduced. It has a closed loop in which boilers generate a steam flow up to 800 kg/h. Steam flow of known wetness up to 12% is generated by cooling down a dry steam flow by a heat exchanger. The wetness is calculated from the enthalpy the heat exchanger draws from the dry steam flow. Analysis of the facility performance, calibration results of an orifice flowmeter calibration, and uncertainty analysis are described.