Biomedical Engineering Reference
In-Depth Information
One established large-scale straw biogas demonstration project is located in
Tangshan City, Hebei Province. This project adopts special double-membrane
technology, and has a total reactor volume of 600 m 3 and annual biogas production
of 300,000 m 3 . The biogas production can meet the needs of household use for fuel
and lighting. Thus, it holds great promise in resolving the contradictions between
fuel, feed and fertilizer.
Zibo, in Shandong Province of China, has successfully started two large-scale
straw biogas projects and found a new way to make better use of corn stalks from
more than 600 hectares of land. 20 million Yuan has been invested to build a
1-km 2 large-scale straw biogas project, including a 1,000-m 3 methane fermenta-
tion tank and a 600-m 3 air tank. Now the main part of this project has been
finished. Upon the completion of project construction, it will annually consume
200 hm 2 of corn stover, produce 1,000 m 3 Of biogas per day, and will be able to
meet the daily energy needs of 700-1,000 residents. In addition, it will produce
1,200 tons of high-quality solid organic fertilizer and 30,000 tons of liquid organic
fertilizer, bringing an annual direct economic benefit of 40 million Yuan.
Another straw biogas project is also under construction in Zibo City. It has a
total investment of 500 million Yuan and total fermentation tank volume of 3,000
m 3 . The first-stage construction is under way, with an initial investment of 180
million Yuan. A 1,000-m 3 large-scale biogas fermentation tank will be built in this
plant, covering an area of 1 hm 2 . So far, more than half the project has been
finished. It is expected to provide a direct
economic benefit
of more
than
80 million Yuan after completion.
In addition, a centralized straw biogas supply system is planned in Jintan City,
Jiangsu Province. This system will adopt medium-temperature fermentation
technology. The main works consist of four 75-m 3 red-mud plastic anaerobic
tanks, one 21-m 3 regulating reservoir, one 100-m 3 reservoir bag, and one 64-m 3
liquid storage tank. When finished, the project will handle annually about 80 tons
of crop stalks and produce biogas to meet the need of 100 households [ 15 ].
The main challenges for lignocellulosic waste biogas technology facing China
are as follows:
1. Efficient pretreatment technology is still lacking. It is difficult to handle straw in
a fermentation system without pretreatment, because the straw easily floats and
crusts in the fermentation liquor. The solid-state fermentation technology also
faces problems such as poor mass transfer and gas release, high mixing resis-
tance and easy acidification. Thus, straw pretreatment is necessary to overcome
these restrictions. However, pretreatment technology is currently still in its
early stages of development in China. No pretreatment methods are mature
enough to be ready for large-scale biogas production application.
2. High-rate anaerobic digestion reactors specially designed for straw treatment
are needed. Most of the existing anaerobic digestion reactors for biogas pro-
duction have been designed for digestion of easily degradable substrates, such
as manure and food-processing wastewater. These anaerobic digestion reactors
have a very wide scope of applications, but they are not suitable for anaerobic
Search WWH ::




Custom Search