工艺说明
Process description
本回收装置由缓冲罐、压缩、干燥、制冷、贮罐等单元组成，用于回收化肥沼气等厂过程中产生的二氧化碳，并将其纯化以供使用。
The recovery unit is composed of buffer tank, compression, drying, refrigeration, storage tank and other units. It is used to recover carbon dioxide generated in the process of fertilizer and biogas plants and purify it for use.
缓冲
buffer
沼气回收甲烷生产过程排出的二氧化碳气体先经缓冲罐稳定气体压力，同时也起到分离作用。然后二氧化碳气体借助于二氧化碳气体压力经干燥塔净化，达到脱水目的。
The carbon dioxide gas discharged during the methane production process of biogas recovery is stabilized through the buffer tank, and also plays a separation role. Then carbon dioxide gas is purified by drying tower with the help of carbon dioxide gas pressure to achieve dehydration.
干燥与过滤
Drying and filtering
经净化后的二氧化碳进干燥器，二氧化碳从上部进入分子筛床，二氧化碳经分子筛床层吸附脱除其中的水分；干燥器为切换操作，即当一台处于8小时的吸附状态时，另一台则处于再生冷吹状态，再生气为低压残气，来自后续工段的低压常温残气经电加热器加热后，从再生床的下部通过分子筛床层，加热脱除分子筛中被吸附的水分杂质，经再生，以备再次转入到吸附状态。
The purified carbon dioxide enters the dryer, the carbon dioxide enters the molecular sieve bed from the upper part, and the carbon dioxide is absorbed by the molecular sieve bed to remove the water therein; The dryer is in switching operation, that is, when one is in the 8-hour adsorption state, the other is in the regeneration cold blowing state, and the regeneration gas is the low-pressure residual gas. The low-pressure normal temperature residual gas from the subsequent sections is heated by the electric heater, and then heated from the lower part of the regeneration bed through the molecular sieve bed layer to remove the adsorbed moisture impurities in the molecular sieve, which is regenerated for the purpose of being transferred to the adsorption state again.
压缩与冷却过程
Compression and cooling process
来自的二氧化碳气体，进入压缩机(带有中间冷却及末级冷却)，二氧化碳经三段压缩冷却后，在压力2.5MPa，常温状态下去下游继续加工处理。
The carbon dioxide gas from the compressor (with intermediate cooling and final cooling) enters the downstream for further processing at a pressure of 2.5MPa and normal temperature after being compressed and cooled in three stages.
分离与除杂质
Separation and impurity removal
自压缩机来的二氧化碳经冷却、再次分离游离水，二氧化碳去净化床，其中可吸附的杂质被除去，二氧化碳从床层上部排出去干燥器。
The carbon dioxide from the compressor is cooled and the free water is separated again. The carbon dioxide goes to the purification bed, where the adsorbable impurities are removed. The carbon dioxide is discharged from the upper part of the bed to the dryer.
冷却与精馏过程
Cooling and distillation process
经前述净化处理的原料气进冷却器的管内，在此原料气被管外来自残气总管的低压残气冷却之后在液化器中被管外蒸发的R717继续冷却冷凝，进二氧化碳精馏塔，在塔内利用精馏的方法脱除原料气流中的不凝气体等杂质，在再沸器得到液体二氧化碳产品，产品再经节流至1.7MPa，温度约-25℃去原装置产品贮罐，塔釜的热源为来自冷冻系统冷凝器上部抽取的气体，为塔顶回流冷凝器提供冷源的是节流后的液体氨，控制塔底二氧化碳含量达到工业级为前提，未被冷凝的，含不凝气杂质的气体则从冷凝器顶排出，并经压力调节阀节流为低温残气去冷却器回收冷量。
The purified feed gas goes into the pipe of the cooler, where the feed gas is cooled by the low-pressure residual gas from the residual gas header outside the pipe, and then continues to be cooled and condensed by the R717 vaporized outside the pipe in the liquefier. The feed gas goes into the carbon dioxide rectifying tower, where the non condensable gas and other impurities in the feed gas flow are removed by rectification. The liquid carbon dioxide product is obtained in the reboiler, and the product is throttled to 1.7MPa, The temperature is about - 25 ℃ to the original product storage tank. The heat source of the tower bottom is the gas extracted from the upper part of the condenser of the refrigeration system. The liquid ammonia after throttling is used to provide the cold source for the tower top reflux condenser. On the premise that the carbon dioxide content at the bottom of the tower reaches the industrial level, the gas that is not condensed and contains non condensable gas impurities is discharged from the top of the condenser, and is throttled by the pressure regulating valve to the low temperature residual gas to the cooler to recover the cold energy.
产品贮存
Product storage
来自再沸器塔釜的液体二氧化碳经液位调节阀减压至压力1.7MPa，温度约-25℃后去二氧化碳贮罐，由于来自再沸器的液体经节流后必然产生少量气体，这部分气体连同在贮存过程产生的蒸发汽体一并从罐顶上部的出口管排出，并经压力调节阀减压成低温残气去残气总管，在冷却器中回收冷量。
The liquid carbon dioxide from the tower bottom of the reboiler is depressurized to a pressure of 1.7MPa through the liquid level regulating valve, and then goes to the carbon dioxide storage tank after the temperature is about - 25 ℃. Since the liquid from the reboiler will inevitably produce a small amount of gas after throttling, this part of gas, together with the evaporation vapor generated during the storage process, will be discharged from the outlet pipe at the top of the tank, and reduced to low temperature residual gas through the pressure regulating valve to the residual gas header, where the cold energy will be recovered in the cooler.
The above is a detailed introduction to biogas purification, and we hope it will be helpful to you. If you have any questions, please contact us. We will provide services for you with our attitude https://www.hneee.net
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2022-12-27
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