对省级天然气管网设施公平开放与监管的思考——以陕西省为例

天然气管网设施公平开放和依法监管是绝大多数市场化比较成熟国家的一致选择。中国的天然气管网改革才刚刚起步,特别是在省级管网设施的监管方面,面临诸多现实问题。为此,以陕西省为例,剖析了我国当前省级天然气管网公平开放面临的主要问题:(1)省管网公司采取统购统销模式,不适应公平开放制度管输业务独立的客观要求;(2)省内管输价格管理办法和成本监审办法待建立,管输价格合理性亟待监审;(3)储气调峰和两部制管输定价缺位,不适应公平开放定价规则;(4)居民和非居民用气实行"双轨"制,不利于市场健康快速发展;(5)储气调峰设施建设滞后,影响供气稳定性和开放准入;(6)管网开放更具操作性的规章制度准则有待于完善。由此建议近期的监管工作重点应从以下5个方面入手:(1)督促省内管输企业扎实履行信息公开义务;(2)监管管网设施信息和运营信息公开的及时全面真实有效;(3)推动省内管输价格管理办法和成本监审办法尽早出台;(4)推动省内管网公司管输与销售、管输与下游业务分离;(5)推动大用户直供,改变省网公司统购统销模式。

Operation optimization of a hydrogenation feed combustion furnace based on the response surface methodology

In a natural gas purification plant, the hydrogenation feed combustion furnace is confronted with high fuel consumption and high outlet flue gas temperatures. In view of these problems, the operation parameters were optimized by means of response surface methodology (RSM) and numerical simulation. Firstly, a model for hydrogenation feed combustion inside the furnace was established by using CHEMKIN based on GRI-Mech 3.0 methane chemical reaction mechanism and Fluent temperature field analysis, and the calculation results were verified by the field test data. Secondly, the influential laws of flow rate of fuel gas, air/low pressure steam, and upstream exhaust at the inlet on the flue temperature and hydrogen composition concentration at the outlet were numerically analyzed using the orthogonal experiment design method. Finally, the operation parameters at the inlet of hydrogenation feed furnace were optimally designed by using the response surface methodology. It is indicated that an incomplete combustion reaction between methane and air happens in the furnace and the effect of steam on combustion is negligible; that the temperature and hydrogen concentration of outlet flue gas are most affected by the flow rates of air and fuel gas, respectively; that decreasing both flow rates collaboratively is useful for reducing the outlet flue gas temperature of the furnace while the hydrogen concentration is kept at a certain level; that by virtue of orthogonal experimental design and RSM, the effects of each inlet parameter on the temperature and hydrogen concentration at the outlet can be analyzed accurately and the optimal operation parameters in the corresponding working condition can be predicted effectively; and that after the optimization, the temperature at the outlet of the hydrogenation feed furnace drops by 57 K, mol fraction of hydrogen at the outlet increases by 0.41% and fuel consumption declines by 7.51%.