| 摘要 |
FIELD: technological processes. ^ SUBSTANCE: method may be used in automation of mixed fodder preparation process. Method includes mixing of loose mixed fodder with hot granules, maintenance of prepared mixture in heat exchanger, its cooling by air, crushing, fractioning of loose mixed fodder and crushed granules mixture into large, medium and fine fractions with further coating of medium fraction by fat layer in mixer and its release as finished product, return of large fraction for additional crushing and withdrawal of fine fraction for granulation, air cooling in evaporator and its supply in closed cycle mode for cooling of loose mixed fodder and hot granules mixture. Prior to supply for cooling of loose mixed fodder and hot granules mixture, air is cooled in heat-exchanger-recuperator of steam ejector refrigerating machine that works in closed thermodynamic cycle. Steam generator is used to produce working steam, which is sent under pressure into ejector nozzle, at that reduced pressure and temperature of 4-7C are created in steam ejector refrigerating machine with supply of cooling agent vapours to heat exchanger-recuperator for air cooling. Produced mixture of cooling agent vapours and working steam downstream ejector is separated into two flows, one of which is sent to pelleting press, and the other one - to condenser for fat heating. One part of water condensate created in condenser is sent to evaporator for make up of water loss, and the other one, together with condensate produced in process of air cooling in heat-exchanger-recuperator, is first drained into condensate collector, and then to steam generator with creation of closed cycle. In process of loose mixed fodder and hot pellets mixture cooling in heat exchanger of steam ejector machine, underpressure value is additionally measured in evaporator, as well as flow of cooling agent vapours at the inlet and outlet to and from heat-exchanger-recuperator, and also condensate level in evaporator. Measured values of air moisture content prior to and after mixture cooling and its flow rate in heat-exchanger-recuperator are used to define amount of water vapours in spent air, which is used to establish ejection coefficient of steam ejector refrigerating machine by action at ratio of working steam flow rates supplied to nozzle of ejector, and ejected vapours of cooling agent, by means of working steam flow rate variation. Current value of heat transfer coefficient is defined from cooling agent to air via cooling surface of heat-exchanger-recuperator by air temperature at the inlet and outlet to and from heat-exchanger-recuperator, cooling agent temperature at the inlet to heat exchanger-recuperator and air flow supplied for cooling of loose mixed fodder and hot pellets mixture. If temperature of air supplied for cooling of loose mixed fodder and hot pellets mixture deviates from preset interval of values to the side of increase, heat transfer ratio is increased by reduction of ejection coefficient acting to increase working steam flow. If temperature of air supplied for cooling of loose mixed fodder and hot pellets mixture deviates from preset interval of values to the side of decrease, heat transfer ratio is decreased by increase of ejection coefficient acting to decrease working steam flow. Fat temperature downstream condenser is used to specify preset value of fat upstream nozzles at the inlet to mixer. ^ EFFECT: higher quality of mixed fodder preparation. ^ 1 tbl, 1 dwg |
