First, the significance of producing high protein feed from alcohol waste residue

In China's food industry, alcohol, starch sugar, monosodium glutamate, citric acid and other industries mainly use grain as raw materials. 1988 used about 5 million tons of grain, but the utilization rate of raw materials was low, and at least 30-40% of raw materials became waste water and waste residue. 1988 China produced alcohol1080,000 tons and discharged alcohol 150. Ten thousand tons of high-concentration waste liquid, corn only consumes starch in the process of making alcohol, which is wasted in protein. The dry matter content in distiller's grains waste liquor reaches 5-8%, and the total amount of residual organic matter in 1 ton alcohol distillation waste liquor is above 500kg, which is really considerable every year. The biological oxygen demand (BOD) and chemical oxygen demand (COD) of waste liquid discharged from alcohol production are as high as 20000-30000 ppm (the national discharge standard is 60P). Afternoon) and 40,000-s 000 op. P.M (the national emission standard is 100 op. p. m), so the environmental pollution is very serious.

The developed countries in the world attach great importance to this and adopt different ways to treat the waste distiller's grains and treat the environment.

The most successful way to thoroughly pollute is to make high-protein feed from distiller's grains waste liquid by all-dry method, which is called DDGS abroad. The content of protein is as high as 27~30%. This is a project to turn waste into treasure. The production of 1 ton alcohol co-production 1 ton high protein feed costs 500 600 yuan/ton and the price is 900 yuan/ton. A fine sprinkling plant with an annual output of10.5 million tons can make a profit of 450 yuan a year.

China has a large population. To improve people's lives, we must vigorously develop aquaculture. The State Council plans to use 50 million tons of compound feed in 1990, and protein needs 6 million tons. In China, grain cakes can provide at most half, and 3 million tons of protein (7 million tons of cakes) are needed. Therefore, importing fish bone meal consumes about $200 million in foreign exchange every year. It can be seen that the production of high-protein feed from waste distiller's grains can not only turn waste into treasure and increase economic benefits, but also have great significance in controlling environmental pollution, alleviating the shortage of compound feed in China and developing aquaculture.

Two. General situation of comprehensive utilization of distiller's grains at home and abroad

With the increasingly strict environmental protection requirements and the decline of economic benefits of corn price increase alcohol factory, the treatment of alcohol waste grains has been paid more and more attention, which mainly has the following uses:

1. Using distiller's grains to cultivate feed yeast. The main technological process is to separate distiller's grains waste liquid into filter residue and filtrate by centrifugation or precipitation, and the filter residue is directly dried into feed, and the filtrate is used to cultivate yeast. Every cubic meter of alcohol waste liquid can produce yeast 12~ 15kg, its protein quality reaches 40-45%, and the optimum culture temperature is 35℃. The production of 1 kg yeast requires 10m3 air, and the BOD removal rate is. Some countries in the Soviet Union and Eastern Europe often use this method to treat distiller's grains waste liquid, and factories in China, such as Xuzhou Alcohol General Factory, which produces alcohol from potatoes, are also actively experimenting. The key technology lies in the screening of yeast, which not only consumes the substances accumulated in the waste liquid, but also cannot metabolize itself to avoid adverse effects on various processes of alcohol fermentation. Candida SH- 1 and No.2 are used in China, and a small amount of urea (0.06-0. 1%) and phosphoric acid (0.02%) are added. The existing problems are incomplete pollution control and high electricity and gas consumption.

2. Ferment the waste distiller's grains to produce distiller's grains after biogas separation, and put the waste liquid into a large biogas tower for fermentation for 10- 12 days to produce biogas. This method is widely used in foreign countries such as Japan and India. Domestic Nanyang Alcohol Factory, Shandong Penglai Winery and Shandong Longkou Winery have all made achievements in producing biogas from distiller's grains and producing high-protein feed from distiller's grains. Practice has proved that IM3 distiller's grains can produce 22M "biogas, with the removal rate of B [] D reaching 90% and COD reaching 86%. Its disadvantage is that the fermenter occupies a large area, the fermentation period is long, and the activated sludge has to be treated by biological filtration, otherwise it still cannot meet the discharge standards. Biogas is not only a fuel and power raw material, but also a very important chemical raw material. For example, if methane is chlorinated, carbon monochloride, carbon dichloride, carbon trichloride and carbon tetrachloride can be produced.

3. Production of high-protein feed from alcohol waste liquor The world began to produce high-protein feed from alcohol waste liquor in the mid-1960s, and gradually improved from 65438 to 0975. Its technological process is to divide distiller's grains into two parts: filter residue and filtrate. Part of the filtrate after precipitation returns to alcohol to produce diluted water as cooking raw materials, and most of it enters evaporation equipment for evaporation and concentration to become cold dry substances. 40-45% of thick pulp and filter residue enter a dryer for drying, and finally become a product with more than 90% of dry matter, and then be made into granular feed with a protein content of more than 27%. At present, the United States and western Europe are widely used, and there is no complete set of processing equipment in China. Beijing Alcohol Factory imports complete sets of equipment with an annual output of 40,000 tons of DDGS from Norway, and Henan Super Alcohol Factory imports complete sets of equipment with an annual output of10.5 million tons of DDGS from France.