Advances in Biogas Technology - Biotechnology in China: Biofuels and Bioenergy - page 131

Table 5 Major engineering facilities of the Deqingyuan biogas power project
Treatment unit Engineering facility Dimension Number Dolid retention time,

d

1,000 m 3 Pretreatment Collecting pool 1 2

1,000 m 3 Hydrolysis pool 1 1.5

3,000 m 3

Anaerobic digestion Anaerobic digester 4 20

4,000 m 3 Second fermenter 1 7

50,000 m 3 Biogas slurry Storage pool 1 90

20 m 3

Treatment and
utilization
of biogas

First biodesulfurizer 4

120 m 3 Second biodesulfurizer 1

2,150 m 3

Two-film dry biogas
storage

1

Generator 1,064 kW 2

generation, which marked a new stage of Deqingyuan's recycling economy and
sustainable development. Currently, the biogas yield of this plant is 7 million
m 3 and the electricity yield is 14 million kWh. The Deqingyuan biogas power plant
is established under joint support from the United Nations Development Program
(UNDP) and Global Environment Facility (GEF): The demonstration project of
biogas power technology in the world. It is an important demonstration of energy
conservation, emission reduction and low carbon economy development in China.
The schematic diagram of the Deqingyuan biogas power project is shown in
Fig. 2 . Major engineering facilities are given in Table 5 .
The major operational parameters of the Deqingyuan biogas power project are
described below:
1. Anaerobic fermentation is performed at 38 C in the fermenter kettle with
compound CSTR technique (10% TS). The biogas production rate and yield
was 1.9 m 3 /(m 3 d) and 7 million m 3 , respectively.
2. This project adopts the combined heat, power and fertilizer production process.
The biogas produced is utilized for electricity production by two 1,064 kW
electric generators (Jenbacher). The annual average electricity and heat gen-
eration are 14 million kWh and 56 million MJ, respectively. The electrical
efficiency of the generators is 38%, while the total heat and electrical efficiency
of the generators is 80%. The biogas slurry can be used as fertilizer in the
surrounding apple/vineyard (1 million acres) and the feed base (1 million
acres). Thus, zero discharge of farm wastes can be achieved.
3. This project uses hydrolytic sand removing techniques for the pretreatment.
The egg-chicken manure is characterized by high sand content. Pretreatment by
hydrolysis can remove 80-90% of the sand, ensuring the normal operation of
subsequent processes.
4. Biodesulfurization technology is used to remove H 2 S from the produced biogas.
The content of H 2 S in the biogas was 3,000-4,000 ppm. After the two-stage
biodesulfurization process, the content of H 2 S can be reduced to less than 200
ppm, which can meet the requirements of the electricity generator operation.