AbstractThis paper introduces the current situation of the food waste treatment industry in China. There are some technological problems to be solved urgently, the key oil water solid separation equipment, the development trend of food waste treatment, the structural characteristics of Haishen brand horizontal screw centrifuge, and its application in the food waste treatment industry.
Keywords: centrifuge; kitchen waste; three-phase centrifuge; crusher separator
Preface
The national development and Reform Commission, the Ministry of Finance and the Ministry of housing and urban rural development approved 66 pilot cities for resource utilization and harmless treatment of kitchen waste. On May 1, 2013, the industry standard of the people's Republic of China "technical specification for food waste treatment" was issued. It can be seen that, from the perspective of market and policy, food waste treatment has become an emerging industry, and its market prospect is bright again and again. According to the market survey: at present, the daily amount of kitchen waste in China is 170000 tons / day. A large number of kitchen waste, kitchen waste and domestic waste are surrounded, which poses a great threat and pressure to the people living in the city. The "garbage siege" has always been a difficult problem for urban managers. As a result, the "waste oil", "garbage pig" and other food safety conditions seriously threaten the health of every citizen. Therefore, the construction of food waste treatment plant is an important measure to improve the environment and a major event related to the national economy and people's livelihood. The treatment capacity of each kitchen waste treatment plant is 100-500 tons / day. It can be seen that 340-1700 large-scale kitchen waste treatment plants should be built nationwide to meet our living needs.
1. It is urgent to solve the problem of process standard
"If we don't treat garbage properly today, tomorrow we will become a nation standing on garbage.". The resource treatment of kitchen waste can reduce the pressure of domestic waste treatment facilities; eliminate the hidden dangers of food safety such as waste cooking oil and hogwash from the root; and obtain biogas, biodiesel, organic fertilizer, high protein feed and other products through different resource treatment technology routes, so as to realize the strategic policy of sustainable development of circular economy.
Kitchen waste is a part of urban garbage, and it is also one of the most difficult to treat. Cities are now trying to turn it into resources. According to the research results, there is no unified treatment process for food waste treatment plants. Therefore, the state should introduce a unified food waste treatment process, which can effectively implement resource sharing, reduce investment costs and save construction cycle 。 According to the investigation, environmental protection enterprises implement strict confidentiality system of technology, equipment and technology, which restricts the healthy development of the industry. The environmental protection enterprises engaged in food waste treatment have different starting time. As early as 2008, some have just started, and most of them have started in 2011. Its strength is strong and weak, and its scale has its own size. Their treatment processes are basically different, and their emphasis is also different. Some focus on the feed processing of garbage, some focus on the extraction of waste oil, some focus on biogas power generation and organic fertilizer production, and some focus on the extraction of light substances. Although there are many differences, but they have an inseparable common ground, that is, from the garbage Taobao, from the garbage disposal to obtain greater benefits.
Judging from the current domestic newly built kitchen waste treatment plants, the scale ranges from 100 tons per day to 1000 tons per day, and its construction cost ranges from tens of millions to hundreds of millions of yuan. It seems that the government is willing to invest in environmental protection. What is surprising is that each design unit has designed different treatment schemes according to their thinking mode and geographical environment. For this industry, there is no unified standard, which is also the main reason for the diversity of treatment technology, and also an important bottleneck restricting the rapid development of the industry. Therefore, we call on the relevant departments to enact relevant laws and regulations as soon as possible, reasonably standardize the treatment process of food waste, so as to quickly solve the problem of environmental pollution.
2. Technical problems to be solved
After the completion of the kitchen waste disposal plant, it can find a way out for the food waste by recycling, reducing and harmless, which is more conducive to eliminate "gutter oil" and "garbage pig" from the source, and also avoid the direct discharge of kitchen waste into the sewer, causing environmental pollution. However, it is not a simple thing to deal with the kitchen waste. In the process of treatment, the separation of oil, water and solid has made many environmental protection units have no strategy and need mature technical support. However, the engineering and technical personnel of Haishen Electromechanical General Plant have summarized their experience in long-term research and exploration, and designed a complete set of treatment technology and the most advanced separation equipment in China Prepare three-phase centrifuge. The separation effect is extremely high.
3. Introduction of kitchen waste treatment process
Due to the complexity of kitchen waste treatment process, limited to space, here is a brief introduction of its basic process. If necessary, you can contact Haishen Electromechanical General Plant at any time, and Haishen electromechanical will serve you wholeheartedly.
The basic technological process is as follows: food waste collection and transportation → separation → crushing → pulping → heating → oil water solid separation → anaerobic fermentation → methane production. From the perspective of technological process, the collection and transportation of kitchen waste mainly depends on the restriction of various laws and regulations by environmental protection departments to ensure timely and quantitative collection and transportation of food waste from hotels, restaurants and group canteens to the garbage treatment plant. It is a relatively easy thing. The next step will be sorting, crushing and pulping of kitchen waste, which is not difficult. Many enterprises adopt different methods In order to achieve the common purpose of separation, comminution and pulping, the final goal is to carry out the separation of oil, water and solid in the centrifuge after reasonable and standardized treatment. However, the construction cost is very expensive and the equipment volume is huge. However, the engineering and technical personnel of Haishen Electromechanical General plant have developed a new way to change the traditional way of thinking and develop the centralized separation- The crushing and separating machine of crushing and pulping can effectively separate light substances, oil, water, sundries, mud, sand, ceramics, glass, iron and so on, and make slurry of the required size. It has beautiful design, complete functions, stable operation and small size. It is the first choice for every kitchen waste treatment plant. The next step is heating. Heating can also be diversified. The biogas generated by kitchen waste can be used for combustion and heating, and other forms of heating can be used. The most urgent task is to separate the oil, water and solid, which is the most important part of food waste treatment. At present, there are not many equipment for separating oil, water and solid in the market, and a small amount of equipment is also imported from abroad. However, in the vast land of China, due to the huge differences in food culture between the north and the south, many of the imported equipment have failed. According to this characteristic, Haishen Electromechanical General Factory has made a comprehensive study and comparison of Chinese catering culture, and has made centrifuges with different structures for different regions, thus solving this fundamental contradiction. Here is the work of anaerobic fermentation and methane production. This is a very mature technology, which can be handed over to the manufacturers with professional qualifications. I believe they will do better. For the treatment of biogas residue, Haishen centrifuge is more superior and reliable.
Introduction of Haishen brand special centrifuge for food waste treatment
4.1 working principle of three-phase centrifuge
According to the characteristics of food waste difficult to be treated, Haishen Electromechanical General Plant selects the three-phase horizontal screw centrifuge with independent intellectual property rights for separation. The horizontal screw centrifuge is mainly composed of column cone drum, screw unloader, differential mechanism, bearing seat, frame, cover, main and auxiliary motors and electrical system. Under the strong centrifugal force of high-speed rotation of the centrifuge, the material can be fully separated, and the machine can run continuously for 24 hours. The main motor drives the centrifuge drum, and the differential connected to the drum realizes the speed difference between the drum and the screw through the planetary gear differential principle, so as to realize the oil-water separation and solid material pushing process. The centrifuge has the function of automatic control of differential speed. As the solid content of material may fluctuate, the differential speed control system is used to ensure the stability of differential speed, to achieve constant mud biscuit degree and clear liquid phase, so that the separation effect is in the best state. The heavy phase liquid and light phase liquid are respectively pressed out from the overflow port of heavy phase liquid and light phase liquid to achieve the separation of oil, water and solid.
4.2 structural features
The structure of horizontal screw centrifuge is shown in the figure. It is mainly composed of main motor, auxiliary motor, differential, screw body, drum, main bearing, frame, hood, transmission device, etc. The core of Haishen centrifuge is to separate oil, water and solid, and achieve the maximum effect because of its special mechanical structure, advanced design concept, good quality and perfect combination of military technology, which has made this industry a great success. The structural principle of oil-water-solid separation is that two liquid outlets are designed at the position of liquid outlet, one is light phase liquid outlet and the other is heavy phase liquid outlet. Under the action of centrifugal force, solid substances are deposited on the inner wall of the drum and are continuously pushed by screw pusher scrape it out of the machine. The separation of oil water solid is realized. In addition, the centrifuge also adds floater capturing equipment, which can effectively press the light substances such as prickly ash seeds, pepper seeds and foams into the solid, thereby ensuring the purity of oil water. This machine adopts the most advanced special structure design in the world. It has the characteristics of better performance, larger processing capacity, better separation effect, energy saving, stability and reliability, and easy operation. The product has passed the ISO9001-2008 quality system certification. The mechanical properties are higher than the standard of JB / t502-2004.
4.3 separation parameters
4.3.1 material characteristics
Solid content of feed: 1-5%
Feed temperature: 60-90 ℃
Feed oil content: 2-3.5%
4.3.2 separation index
Treatment capacity: 5-50m3 / h (currently, Haishen has more than lws350, lws480, lws620, lws430 and lws580 for the treatment of kitchen waste oil water solid)
Oil content in water: ≤ 1.5%
Water content in oil: 3-6%
Moisture content of slag: 75-80%
Working system: 24h
The spring of environmental service industry is coming
Since the 12th Five Year Plan, the innovation of service mode and the development of comprehensive environmental service industry have become the main driving force of the State Council and the Ministry of environmental protection to promote the development of environmental industry. The 12th Five Year Plan for the development of energy conservation and environmental protection industry also puts the environmental service industry into the development focus. It is planned to achieve an output value of 500 billion yuan by 2015, and more than 50 enterprises with an annual output value of more than 1 billion yuan. In the absence of mature business model in the environmental protection industry, the next stage of environmental protection market development direction will be mode innovation, and the environmental service industry, which has been widely favored by the industry, may enter a substantial start-up period.
