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CN-121991731-A - Biogas dehydration method and system

CN121991731ACN 121991731 ACN121991731 ACN 121991731ACN-121991731-A

Abstract

The invention relates to the technical field of biogas treatment, in particular to a biogas dehydration system which comprises a dehydration tank, a gas inlet, a dehydrator, a flow guide pipe, a liquid level meter connector and a water outlet, wherein biogas enters the dehydration tank from the gas inlet, moves downwards in the flow guide pipe, mechanical water carried by the biogas is separated and deposited at the bottom of the dehydration tank by utilizing inertia force, the upward flowing gas is discharged through the dehydrator, the water level of the dehydration tank is monitored in real time by a meter connected with the liquid level meter connector, the water outlet is used for discharging the mechanical water deposited at the bottom of the dehydration tank, an electromagnetic valve is connected to the water outlet, and the opening and closing of the electromagnetic valve are automatically controlled by a liquid level controller to drain. The invention realizes the high-efficiency separation, self-adaptive control, safe drainage and intelligent operation of the biogas dehydration system by integrating mechanical separation, interval liquid level control, feedforward compensation type dynamic threshold adjustment and intelligent diagnosis of the drainage process.

Inventors

  • WU LILI
  • XU GUOSHENG

Assignees

  • 南京远大环境工程有限公司

Dates

Publication Date
20260508
Application Date
20251016

Claims (8)

  1. 1. A methane dehydration system is characterized by comprising a dehydration tank (1), a gas inlet (2), a dehydrator (3), a guide pipe (4), a liquid level meter connector (5) and a water outlet (6), wherein methane enters the dehydration tank (1) from the gas inlet (2), moves downwards in the guide pipe (4), mechanical water carried by the methane is separated and deposited at the bottom of the dehydration tank by utilizing inertia force, the upward flowing gas is discharged through the dehydrator (3), the water level of the dehydration tank (1) is monitored in real time by a meter connected with the liquid level meter connector (5), the water outlet (6) is used for discharging mechanical water deposited at the bottom of the dehydration tank, an electromagnetic valve is connected to the water outlet (6), and the electromagnetic valve is automatically controlled to be opened and closed by a liquid level controller to drain.
  2. 2. The biogas dehydration system according to claim 1, wherein the liquid level meter interface (5) comprises a high liquid level meter interface and a low liquid level meter interface, and the interval control of the liquid level in the dehydration tank (1) is realized through the high liquid level meter interface and the low liquid level meter interface.
  3. 3. The biogas dehydration system according to claim 2, wherein the biogas dehydration system is characterized in that a liquid level measuring instrument is connected through a liquid level meter interface (5) arranged on the side wall of a dehydration tank (1), the liquid level height is monitored in real time, when the liquid level measuring instrument detects that the liquid level reaches a high liquid level set value, a high switching value signal is output to trigger an electromagnetic valve at a water outlet (6) to be opened, and when the liquid level is lowered to a low liquid level set value, the liquid level measuring instrument outputs a low switching value signal to control the electromagnetic valve at the water outlet (6) to be closed.
  4. 4. A biogas dewatering system according to claim 3, wherein the level meter is a magnetic flap level meter.
  5. 5. A method for biogas dehydration using a biogas dehydration system as in claim 1, comprising: S1, introducing methane from a pressurizing fan into a guide pipe (4) in a dewatering tank (1) through a gas inlet (2), enabling the methane to flow downwards in the guide pipe (4) along the axial direction, and enabling mechanical water carried in the methane to impact the guide pipe wall and separate from the air flow by utilizing inertia force generated by rapid change of the air flow direction, so that the mechanical water is settled at the bottom of the dewatering tank (1); S2, returning methane subjected to preliminary dehydration from the bottom of the draft tube (4) to move upwards, performing secondary water removal through a water remover (3) arranged above the draft tube (4), removing residual water mist, and discharging the residual water mist to a boiler burner for combustion; and S3, monitoring the liquid level height in the dewatering tank (1) in real time through a liquid level measuring instrument connected to a liquid level meter interface (5), when the liquid level reaches a high liquid level set value, outputting a control signal by the liquid level measuring instrument to start an electromagnetic valve at a water outlet (6) for automatic drainage, and when the liquid level is reduced to a low liquid level set value, closing the electromagnetic valve to complete an automatic drainage period.
  6. 6. The biogas dehydration method according to claim 5, wherein the liquid level measuring instrument detects a high liquid level signal and a low liquid level signal through a high liquid level instrument interface and a low liquid level instrument interface respectively, so that interval type closed-loop control of the liquid level in the dehydration tank (1) is realized.
  7. 7. The biogas dehydration method according to claim 6, wherein the liquid level threshold dynamic setting method based on feedforward compensation dynamically adjusts a high/low liquid level set value according to biogas flow Q g and water content w, and the liquid level threshold dynamic setting method based on feedforward compensation specifically comprises the following steps: H low = H high -ΔH Wherein H high is a high liquid level set value, H low is a low liquid level set value, H 0 is a reference high liquid level, k is a compensation coefficient, A is the cross-sectional area of the dehydration tank, deltaH is a fixed liquid level difference, and T is a reference time interval.
  8. 8. A biogas dewatering method according to claim 7, wherein the system continuously monitors the drain cycle duration T drain and the rate of liquid level decrease while performing dynamic adjustment of the liquid level threshold When T drain < And is also provided with When R low is less than the threshold, judging that the water discharge of the water outlet is not smooth or the electromagnetic valve is not fully opened, switching to a manual water discharge mode, and when T drain >T max is carried out, judging that the tank bottom is silted or the water discharge pipe is blocked, wherein T drain is the duration of a single water discharge period, For the liquid level drop rate during draining, R low is the liquid level drop rate threshold, T max is the longest allowed drain time.

Description

Biogas dehydration method and system Technical Field The invention relates to the technical field of biogas treatment, in particular to a biogas dehydration method and a biogas dehydration system. Background Biogas is used as a clean renewable energy source and is widely applied to the fields of power generation, heat supply, boiler combustion, purification, preparation of biological natural gas and the like. In practical engineering application, moisture control is one of the key links of the stable operation of a biogas utilization system. Untreated biogas is typically saturated with water vapor and entrained with liquid water droplets (i.e., "mechanical water") that, if not removed effectively, can pose serious hazards to subsequent equipment, including corrosion of pipes and equipment, plugging of pipes, and interference with measurement instruments. Therefore, an efficient dewatering process must be performed before the biogas enters the terminal energy equipment (e.g. boiler, generator). At present, the common biogas dehydration modes mainly comprise three main types of a cooling condensation method, an adsorption drying method and a mechanical separation method, however, the mechanical dehydration system in the prior art still has the following significant defects: 1) The mechanical water separation efficiency is low, the combustion stability is affected by residual water, the liquid level monitoring depends on manual work, and the water is not timely or excessively discharged; 2) The liquid level control mode is simple, and the drainage electromagnetic valve is frequently opened and closed, equipment is easy to damage and the system operation is unstable due to the adoption of single-point liquid level control; 3) The traditional system only depends on a liquid level feedback signal to control, and belongs to a 'post response' mode. The traditional biogas dehydration system adopts fixed liquid level threshold control, cannot adapt to biogas flow and water content fluctuation, causes the problems of drainage hysteresis (with water risk) at high load and frequent drainage (equipment loss) at low load, has obvious time delay, and is difficult to adapt to dynamically-changed operation conditions; 4) The traditional methane dehydration system only realizes 'automatic start and stop of water discharge', lacks effective monitoring on the water discharge process, cannot find problems such as solenoid valve faults, unsmooth water discharge or pipeline blockage in time, and has potential safety hazards of liquid level out of control and methane water; In summary, although the existing biogas dehydration system can realize the basic mechanical water separation function, the existing biogas dehydration system still has obvious short plates in the aspects of intelligent control, dynamic adaptability, operation safety and maintainability. Particularly in small and medium-sized biogas engineering, a dehydration system which is reasonable in structure, intelligent in control, safe, reliable and simple in operation and maintenance is needed to improve the overall operation efficiency and stability. Disclosure of Invention The invention provides a methane dehydration method and a methane dehydration system, which realize the efficient separation, self-adaptive control, safe drainage and intelligent operation of a methane dehydration system by integrating mechanical separation, interval liquid level control, feedforward compensation type dynamic threshold adjustment and intelligent diagnosis of a drainage process. The technical scheme includes that the methane dehydration system comprises a dehydration tank, a gas inlet, a dehydrator, a flow guide pipe, a liquid level meter interface and a water outlet, methane enters the dehydration tank from the gas inlet, moves downwards in the flow guide pipe, mechanical water carried by the methane is separated and deposited to the bottom of the dehydration tank by utilizing inertia force, upward flowing gas is discharged through the dehydrator, the water level of the dehydration tank is monitored in real time through a meter connected with the liquid level meter interface, the water outlet is used for discharging the mechanical water deposited at the bottom of the dehydration tank, the water outlet is connected with an electromagnetic valve, and the liquid level controller automatically controls the opening and closing of the electromagnetic valve to drain water. As an optimization scheme of the invention, the liquid level meter interface comprises a high liquid level meter interface and a low liquid level meter interface, and the interval control of the liquid level in the dehydration tank is realized through the high liquid level meter interface and the low liquid level meter interface. The invention adopts an optimized scheme that a liquid level meter interface arranged on the side wall of the dewatering tank is connected with a liquid level measuring instrument to monitor th