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Ultra-low calorific value gas (ULCVG) not only poses a problem for environmental pollution, but also createsa waste of energy resources if not utilized. A novel reactor, a rotary regenerator-type catalytic combustion reactor (RRCCR), which integrates the functions of a regenerator and combustor into one component, is proposed for the elimination and utilization of ULCVG. Compared to reversal-flow reactor, the operation of the RRCCR is achieved by incremental rotation rather than by valve control, and it has many outstanding characteristics, such as a compact structure, flexible application, and limited energy for circulation. Due to the effects of the variation of the gas flow and concentration on the performance of the reactor, different inlet velocities and concentrations are analyzed by numerical investigations. The results reveal that the two factors have a major impact on the performance of the reactor. The performance of the reactor is more sensitive to the increase of velocity and the decrease of methane concentration. When the inlet concentration (2%vol.) is reduced by 50%, to maintain the methane conversion over 90%, the inlet velocity can be reduced by more than three times. Finally, the highly-efficient and stable operating envelope of the reactor is drawn.

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The expander is a key component of the Organic Rankine Cycle (ORC) power generation system, which has great influence on the system performance. Based on an experiment on a ORC system using the dry working fluid R600a, the thermodynamic parameters at the inlet and outlet of the scroll expander, and the output power under the experimental conditions were obtained. The performance of the scroll expander under variable operating conditions was studied. The effect of the superheat amount, inlet temperature, and inlet pressure on the performance of the scroll expander was analyzed. The results show that the scroll expander has good performance under variable operating conditions. The inlet pressure has the greatest influence on the performance of the scroll expander, followed by the inlet temperature, while the working fluid superheat has the least effect. A change in inlet pressure of about 50kPa results in about 20W of output power at the same inlet temperature variation range. While a change in inlet temperature of about 20 ° C can result in about 15W of output power at the same inlet pressure variation range. The results can provide a reference for the design and operation of the scroll expander. (CSPE)