2. Degreasing: firstly, add 1 kg of meta-sulfuric acid into a large wooden barrel according to 1000 kg of water, stir and mix evenly, then put qualified fresh rapeseed into the wooden barrel for soaking and cleaning for about 10 minute, and disinfect and degrease. 1000 kg sulfuric acid aqueous solution can wash 2000 ~ 3000 kg rapeseed. After elutriation, take it out and drip dry.
3. Into the tank: mix the dried rape flowers with 30% salt evenly, or add salt while entering the tank and sprinkle a layer of salt on the rape flowers. The salt must be spread evenly. When it is about 17 cm away from the tank mouth, use clean water board or straw cover to add stones for compaction, and then use 0. 1% citric acid aqueous solution to soak and submerge the rape flowers to prevent pollution and mildew, and keep the rape flowers hard, fragrant, fresh, tender and bluish yellow. The soaking time is about 15 ~ 20 days, during which the cylinder should be turned over 3 ~ 4 times. Let the salt and rape mix absolutely.
4. Packaging for shipment: take out the soaked rape flowers in the tank, rinse them with clear water, drain the water, box them and weigh them. 30% salt is still mixed evenly, soaked in 0. 1% citric acid aqueous solution, and then sealed for shipment.
Processing equipment and investment: To process 20 tons of rapeseed, it is necessary to build four cement tanks with a length of 3m, a width of 1m and a height of 1m, a large wooden barrel with a diameter of 1m, a sieve dustpan, salt and accessories.