城市天然气采暖的新途径

New Approach for Urban District Heating with gas

随着我国城市能源结构调整和环境保护措施的加强 ,北方地区煤改气 ,以天然气作为主要的采暖一次能源逐渐成为主要趋势。然而 ,由于天然气价格远高于燃煤 ,直接燃烧天然气导致运行成本过高 ,经济效益差。即使采用联合循环 ,热电联产 ,运行费也高于燃煤发电和燃煤供热。我国城市能源系统的另一问题是电力负荷日益加大的峰谷差。城市电力系统的削峰填谷也是困扰电力部门的大问题。面对上述背景 ,本文提出解决上述问题的新途径 :用燃气轮机发电 ,余热作为集中供热系统的热源。机组按调峰方式运行 ,电力负荷高峰发电并供热 ,电力负荷低谷时 ,停止发电和供热 ,由于供热管网及建筑物巨大的热惯性 ,低谷期停止供热 6～ 8h采暖房间室温的降低不会超过 1℃ ,不会影响供热效果。调峰发电可享受高发电电价 ,从而抵消燃气价格高导致的采暖成本上升。按此模式运行 ,目前的“以热定电”方式应改为“热电兼顾” ,甚至于“以电定热”。

As one of the key policies of environment protection, turning to gas from coal for urban district heating become one of the major actions in many cities in north China. However, as the cost of gas in China is much higher than coal, direct heating by gas will rise the cost of district heating. Combined power and heating cogeneration cannot solve the problem due to the low cost of the fire-coal-electricity stations. On the other hand, the increasing of peak-vale difference in electricity demand fazes utility companies a lot. As a solution of above problem, a new approach is present: a cogeneration system with gas as the fuel. Chang the operation mode from“ heating demand first” to“ utility demand first” . During high electrical demand, general electricity and heat by the cogeneration system. When the utility demand goes low, stop both electric generation and heat generation. Because the huge thermal mass both in the piping network and buildings, after 6～ 8 hours stop, drop in room air temperature will be less than 1° C. This means little effect on the comfort level of the heated space. Due to the peak load electricity generation can be paid at quit high price, the cost of heating can be reduced greatly.