| Giving full play to the regional natural advantages of the Hexi region and promoting ecological agriculture in the Gobi is a major decision and deployment made by the government,and it is also a national strategy for establishing an ecological barrier in the west.However,the severe winter climate in the west is a bottleneck restricting the development of Gobi ecological agriculture with the Gobi greenhouse as the carrier.So far,the problem of cold and frost protection in the Gobi greenhouse has not been effectively solved.Therefore,it is imminent to develop the technology and equipment to prevent cold and frost in the Gobi Greenhouse in winter.Gobi eco-agriculture has been strongly developed in recent years,especially in the construction of Gobi greenhouses.The Gobi region is vast and geographically rich,but it is also limited by factors such as the environment and the short time period suitable for growing crops.Therefore,the construction of suitable greenhouses in the Gobi region is of great importance to increase crop yields and thus further increase the income levels of farmers.Although the establishment of greenhouse can increase the yield of crops to a certain extent,it is restricted by natural conditions to a certain extent.For example,when the weather becomes cold,the temperature in the greenhouse will drop sharply,which will easily cause a lot of frostbite to crops.Therefore,adding warming equipment to the greenhouse under certain conditions is an important measure to solve the problem of cold and frost protection in the Gobi greenhouse.In the early days,farmers in the Hexi area of Gansu had a precedent of adding coal stoves in greenhouses.In recent years,with the improvement of environmental protection awareness,coal stoves were added in greenhouses,which polluted the environment seriously.Therefore,the development and utilization of biomass stoves in the Gobi greenhouse have a good prospect.Based on this,this paper designs and analyzes the technology and equipment of biomass pellet warming and antifreeze in Gobi greenhouse in combination with Gobi ecological agriculture.(1)Through the investigation of the climatic conditions in the Gobi region,the design parameters of the greenhouse shed were proposed as follows:9° south by west,10m span,28° light angle,the length of the rear roof was designed as 1.6m,the ridge height was taken as 3.4m,the rear roof angle was adopted as 40°,the wall thickness was designed as 1.8m and the front roof was made of EAV film with better UV protection.The total moisture,ash,volatile content,fixed carbon,heat,density and ignition time of the biomass particles were measured by industrial analysis and specific analysis was carried out.It was found that the level of fixed carbon value has a great influence on the combustion characteristics of the fuel,with a high fixed carbon value and its high calorific value.The analysis of the heat content revealed that the bark had the lowest heat content.The analysis of the combustion characteristics revealed that the only way to make the ignition time of its combustible material shorter was to reduce its total moisture and ash content and to increase its volatile content and fixed carbon.Through the design of the greenhouse and the study of the combustion characteristics of biomass pellets,it is possible to provide a reference basis for the design of subsequent heating and anti-freezing technology and equipment.(2)Combining the characteristics of the greenhouse in the Gobi area and the f combustion characteristics of biomass pellets,this paper,on the basis of the original hot blast furnace,has carried out research on the furnace,furnace jacket,heat exchanger,furnace base,feed bin winch and feed bin of the biomass pellet furnace,carried out the corresponding design,made the two-dimensional diagram and three-dimensional schematic diagram of each component,and can carry out the corresponding processing for each component.The function of each component is explained,and the overall three-dimensional structure diagram of the biomass pellet combustion furnace is made,which has made certain basic preparation for the following design and research.(3)The combustion control of the biomass pellet burning stove is carried out by means of an automatic ignition device.The design uses the AD590 temperature measuring device to be able to monitor the temperature in the greenhouse.If the temperature is lower than the required temperature in the greenhouse within the specified four time periods,the automatic ignition device will automatically ignite the biomass pellet burning stove to heat the greenhouse,and if the temperature in the greenhouse exceeds the required temperature,the combustion in the burning stove will automatically stop.Gobi greenhouse biomass pellet burning stove automatic ignition system,characterised by electric heating elements for silicon nitrogen rods,silicon carbon rods,silicon molybdenum rods,etc.,and with a blower,in 20～50 seconds,the temperature can rise to 800-1800℃,through the blower heat transfer ignition of biomass fuel,simple installation,convenient operation,fast ignition rate,high stability,long service life.(4)The heat exchange of the hot blast stove is mainly carried out in the heat exchanger.In this design,the CFD simulation technology is used to simulate the shell side fluid and the tube side fluid of the heat exchanger of the hot blast stove,and the tube side fluid and the tube side fluid of the heat exchanger are carefully studied.The two flow field characteristics of shell-side fluids are unreasonable,and an optimization scheme is proposed.Two different types of heat exchangers were designed this time,and combined with the temperature field and velocity field,the conclusion was drawn:in the process of straight coiling heat exchange,the inlet thermodynamic temperature of air is 276K,and the outlet thermodynamic temperature is 358.9K.The temperature difference is 82.9℃.Therefore,in this heat exchange process,the air in the shell side is heated by 82.9℃.Compared with the serpentine heat exchanger,the temperature gradient is not uniform,and the temperature of the air heating in the shell side is slightly lower.For this reason,a serpentine heat exchanger is used in the warming and antifreezing technical equipment to improve the heat exchange efficiency. |
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