n-Butanol in the fermentation, coating and pharmaceutical intermediates industry, the boiling point of about 118 ℃, the volatile rate at room temperature is slow, the concentration of tail gas is usually not high but the composition is stable. Compared with low boiling point alcohols such as methanol and ethanol, the condensation temperature of n-butanol is much looser, and the large head can be recovered by adding water cooling at normal temperature. The water solubility is also limited, the condensate can be stratified when standing, and the dehydration burden is lighter than that of ethanol. These two items make the recovery configuration of n-butanol relatively simple: collection in place, condensation is sufficient, layered reuse, and the economy of recovery is a better one among alcohols.
The source of the tail gas of butanol is mainly the respiration of the fermentation tank, the non-condensing gas at the top of the distillation tower and the respiration of the storage tank: the fermentation industry accounts for the largest proportion, although the concentration of the tank respiration gas is not high but exists continuously, and the accumulated solvent loss throughout the year is considerable, which is a clear point of recovery value.
The temperature level is calculated according to the dew point corresponding to the intake air concentration: the high boiling point of n-butanol makes the condensation ratio in the normal temperature section not low. when the intake air concentration is high, the recovery rate of water-cooled two-stage condensation is considerable, and low-temperature cryogenic cooling is only configured when required. The concentration of respiratory gas in the fermentation tank is low, and the benefits of direct condensation are limited. First, collect and increase the concentration according to the tank batch, or merge it into the main pipe and then decide the treatment route according to the concentration. The difference in miscibility with ethanol is most evident on the side of the condensate: the n-butanol condensate is static and layered, the alcohol phase is treated separately from the water phase, eliminating the distillation dehydration load in the ethanol route, and the structure of the recovery cost is completely different.
The condensing load is calculated according to the measured concentration, the main body of the device is selected according to the median load, and the wave crest is accepted by the buffer. This account is calculated clearly in the scheme stage.
The collection end is divided according to the point position: the breathing port and exhaust port of the fermentation tank are connected to the branch pipe, and the air valve is started and stopped according to the tank batch to avoid empty tank suction; The high concentration of distilled non-condensable gas is connected separately. The breathing port of the storage tank is equipped with a collection interface, and the replacement gas is loaded and unloaded and collected together. The condensate side follows the layering route: the condensate is put into the layering tank for standing, the alcohol phase is used after moisture and purity detection, and the water phase is treated according to the solvent content after measurement. The detection before alcohol phase transfer is the last pass, moisture is the first, and the purity is determined by downstream use.
The slope of the pipeline and the low-point drainage should not be ignored: the condensation amount of n-butanol on the pipe wall is larger than that of low-boiling alcohol, and the pipeline liquid accumulation brings intermittent concentration impact. The low-point drainage liquid is included in the daily inspection, and the condensate is recovered to the stratification tank without waste.
| Segment | Features | Configuration Schedule |
|---|---|---|
| Can Breathe | continuous low concentration | Centralized processing by batch collection |
| Distilled non-condensable gas | high concentration | Separate one-way condensation recovery |
| Tank Breathing | Loading and unloading period concentration | Breathing mouthpiece collection interface |
| Condensation temperature level | high boiling point loose | Water-cooled two-stage main |
| Condensate treatment | Can be layered | Layered tank standing for reuse |
| Pipe Drain | Large condensation volume on pipe wall | Low Drain Into Inspection |
Most of the alcohol phase can be directly used after the water content and purity meet the standard, and the first-stage distillation is added to the process sensitive to purity. The reuse depth is determined according to the purpose, the classification ledger of the recycled liquid keeps up, and the quality and destination are well documented.
The difference between the condensate side is the biggest: ethanol and water are soluble and azeotropic, dehydration distillation is the energy consumption head; n-butanol condensate static stratification, save the distillation dehydration load, the recovery cost of the structure is significantly lighter.
According to the accumulated loss of the whole year, the accumulated loss of ethanol and n-butanol in workshops with large number of tanks and long operation time is not small. The measured concentration is first and then calculated. The results of most large-scale workshops are valid.
This article by LuoyangWohong PetrochemicalEquipment Co., Ltd. arranges that the company provides design, manufacturing and operation and maintenance services for condensation recovery, membrane separation recovery and complete solvent recovery devices for chemical and pharmaceutical enterprises. If you need process evaluation or scheme configuration, please contact and exchange.
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