秸秆发酵电厂建设可行性研究

Feasibility study on the construction of a power plant using fuels from straw stalk fermentation power plant

针对我国秸秆资源的特点，提出了采用大型沼气池利用秸秆为原料高温发酵生产沼气，然后通过内燃机组、余热锅炉以及汽轮机组等设备的联合动力循环、沼气代替液化气满足村镇居民的生活用气、沼渣生产有机肥的秸秆综合利用技术路线，该系统采用成熟技术的组合，所有设备均可国产化。介绍了该系统的工艺路线，并分析了其技术可行性与项目经济性。分析结果表明，发电余热完全可以维持沼气池内50～55℃的温度，能够实现高温发酵；以消耗秸秆9万/a（折合含水量15％，原始热值13．5MJ／kg）的发酵电厂为例，能够日产热值为21MJ／m^3的沼气72000m^3，发电量5×10^7kwh／a，生产有机肥4．4万t／a；项目投资回收期大约5年.

Based on the characteristics of straw resources in China, a new way of straw stalks generating electricity and making organic fertihzer is proposed. Biogas is produced in the large-scale biogas digester by fermentation in high temperature, then producing electricity using the biogas by gas-steam combined cycle through engine units, exhaust-heat boiler, turbo-set, etc.. In the system, the techniques have come to maturity and the equipments can be produced in the country. Further more, the biogas can be supplied to residents to replace liquid gas and the dregs can be supplied to the farmer to replace chemical fertihzer. The feasibility of the technology and the benefit of the system is analyzed. The result of analysis shows that the exhaustheat of the system could definitely maintain in 50- 55℃ （temperature） in the biogas digester to ensure the high-temperature fermentation. The power plant uses up to approximately 90 000 t/a of straw stalks （converted to 15 % of water content, 13.5 MJ/kg of original heat value） ,it can produce 72 000 m^3 of biogas that equals 21 MJ/m^3 of heat value every day,5 × 10^7 kWh of power generated and 4.4 × 10^4 torts of organic fertilizer every year. The payhack period of the system is approximately 5 years.