1.3　Biogas Digester Development in China

1.3.1　First Stage—Luo Guorui Biodigester

By the end of 1880's, very simple biodigesters appeared in local rural areas of Guangdong, China (Fig.1.2). In 1929 the first stage digester, called Luo Guorui Biodigester, came out. Luo Guorui constructed a 8m3biogas digester as shown in Fig.1.3

Fig.1.2　The earliest biogas reactor in China

A—fermentative pool; B—gas box; C—inlet; D—land; E—pipe

Fig.1.3

Fig.1.3　Luo Guorui's gas reactor (biogas digester)

1.3.2　Second Stage—Long-distance, Big and Deep Digester

In early 1970's, Chinese second stage digester appeared. This type of digester was characterized by far, big and deep. Long-distance refers to the distance away from kitchen to the site of digester, big refers to the great volume of digester, and deep refers the digester is very high.

1.3.3　Third Stage—Round, Small and Shallow Digester

By the end of 1970s, the biogas digester was upgraded into round, small and shallow form. (Fig.1.4). Round refers to the spherical shape of digester, small refers that the volume of digester is less than 10m3, shallow refer that the height of digester is less than 2m.

Fig.1.4　Sketch of the hydraulic biogas digester structure

1—inlet; 2—inlet pipe; 3—fermentation chamber; 4—gas pipe;5—outlet pipe; 6—hydraulic chamber; 7—removable cover

1.3.4　Fourth Stage—Mini-size and High-efficiency Digester

By the end of 1980s, mini size and high efficiency biogas digester began to be popular in rural area of China (Fig.1.5). This type of digester has a volume of less than 6m3. It produces biogas at a steady level. And it is easy for users to control.

Fig.1.5　Mini-size and high-efficienly biogas digester

1.3.5　Fifth Stage—Commercialized Fiberglass Digester

In 2000, Yunnan Normal University developed a commercialized fiberglass digester for rural areas (Fig.1.6). This type of digester is very popular with Chinese people and is extended in many districts.

Fig.1.6　Commercialized biogas digesters of glass fiber reinforced plastic