JPS58139741A - Desorption and regeneration method by heating - Google Patents

Abstract

PURPOSE:To detect and prevent ignition and runaway by detecting the operating pressure PH of gases on a heating medium side and the operating pressure PA of gases on an adsorbent side and regulating the operating pressure of the gases after desorption and the operating pressure of the circulating gases in the outlet of a heater in such a way that the PA is kept always higher than the PH. CONSTITUTION:The operating pressure PH on a heating medium side is detected by a pressure detecting end 120 from streams 107, 108, 109, 110 of high temp. gases or from an optional position in the heating part, and further the operating pressure on an adsorbent side is detected with a detecting end 121. The set value of PA>PH is detected with a differential pressure transmitting signal 122 and respective control valves 123, 127 are operated by streams 124, 125 according to the detected signal. A desorbing gas 129 passes through the valve 123 then through a stream 130 and is fed from a stream 132 to the next stage by a suction blower 131. A desorbing gas 132 is fed to stages for recovering S, etc. since said gas contains SO2 in a high concn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry flue gas desulfurization method, and particularly to a thermal desorption regeneration method.

The adsorbent is brought into contact with a combustion exhaust gas containing sulfur oxides, and the adsorbent that has adsorbed the sulfur oxides is usually regenerated by thermal desorption 51i. At this time, there is a method in which the adsorbent is brought into direct contact with the granular solid heat medium as the heating medium, and the adsorbent is thermally desorbed and regenerated.In this case, the regenerated adsorbent and the heat medium are classified, and the heat medium is circulated. The drawback was that it was difficult to use and the operation was complicated. Is this a heating medium for this reason? A method of desorbing and regenerating the adsorbent by indirectly contacting the high-temperature gas and the N-absorbing agent using 1IJih waste has been carried out. Except for this, high-temperature gas is kerosene, TL
oil.

It uses the combustion waste of coal, but it uses kerosene and double fuel oil.

Coal combustion exhaust gas mixes with air very efficiently, and even with careful combustion, the excess air ratio f11.05 to 1.2 times, and the heating combustion exhaust gas contains 1 to 4 liters of oxygen. Mixed. For this reason, when combustion exhaust gas and adsorbent are brought into indirect contact for desorption and regeneration, if part of the combustion exhaust gas leaks to the heated side, that is, the adsorbent side, due to cracks in the heat transfer tube, etc., it will not be heated. If the adsorbent is occupied, the temperature of the adsorbent will rise rapidly, creating a dangerous situation. This risk arises because the heat transfer wall surface on the adsorbent side is always in striped contact because H2O gas is generated when the adsorbent is heated and desorbed and regenerated. For this reason, there were eight comments that placed emphasis on reinforcing the intermittent components (heat transfer tubes) for the high-temperature gas and adsorbent, and selecting materials.

The purpose of the present invention is to prevent intermittent members between high-temperature gas and adsorbent from igniting the book and the adsorbent in the worst case scenario where heat transfer is cracked and exposed due to corrosion, etc. The purpose of the present invention is to provide a thermal desorption regeneration method.

In the present invention, even if the barrier member (heat transfer %) between high-temperature gas and adsorbent cracks due to striped contact, etc., and the worst situation occurs, it is possible to prevent the adsorbent from igniting, and to prevent the heating medium from igniting at all times. The operating pressure Pg on the high temperature gas side and the operating gas pressure Pm on the adsorbent side are detected, and the operating pressures on the high temperature gas side and adsorbent side are adjusted so that P A > P ys at all times.
This prevents oxygen from the high temperature gas side from leaking to the adsorbent side. Furthermore, are there any cracks in the intermediary member (heat transfer tube) between the high temperature scum and the adsorbent? ! - In order to detect, gas sampling is performed from the high temperature gas side and 802 in the high temperature gas is measured intermittently or continuously to detect cracks in the interlayer member.

In other words, the adsorbent that adsorbed sulfur * oxide in the adsorption tower was 22
By thermal desorption at 0C to 450C, mainly SoW
, eO*, HtO9 generates a trace amount of CO, -! Ta,
The adsorbent is carbonaceous, and when oxygen is mixed into the heated atmosphere of 400U, it easily ignites and raises the adsorbent temperature, and furthermore, the oxygen that diffuses (oxygen leaked from the hot gas)
This will assist combustion. An object of the present invention is to provide a thermal desorption regeneration method that can detect and prevent these ignition runaways.

FIG. 1 shows a system diagram of thermal desorption according to an embodiment of the present invention.

After the combustion exhaust gas 1 containing sulfur oxides is introduced into the adsorption tower 100, the boiler combustion exhaust gas 2 from which most of the 61L yellow oxides have been adsorbed and removed is sent to the next step.

On the other hand, the adsorbent 3Fi adsorbing sulfur oxides is supplied to the thermal desorption regeneration tower 101. The thermal desorption regeneration tower 101 includes a heating section 103 and a cooling section 105.

The high-temperature waste for heating is produced by the mixed combustion of fuel 4 and air 5 in the combustor 1'02, and the high-temperature combustion exhaust gas 6 is supplied as a temperature-adjusted high-temperature gas 107 to the heating section 103 by a suction pump 106. The gIk layer agent 3 is indirectly heated by the high temperature gas 107 to perform thermal desorption regeneration. The high temperature gas 107 passes through the flow 108 from the heating section 103 and again.
Enters the heating section 103, [rtl 09. 110. 1
11, flow 111 #i flow 112. Divided into stream 7, stream 7 is recycled and a portion of the lll1l hot gas is discharged from stream 112 to the atmosphere.

The adsorbent that has been thermally desorbed and regenerated is then cooled to a predetermined temperature by the cooling section 101. The cooling medium 8 is pumped into the cooling section 101 and removed from the flow 9. The cooled adsorbent 10 is returned to the adsorption tower 100 and recycled.

In the present invention, the flow of high temperature gas is 107,108°109.1
10 or a pressure detection end 120 from any arbitrary point of the heating section.
The operating pressure PM on the heating medium side is detected by, and further,
The operating pressure P of 1 lll of adsorbent (desorption gas) is detected by a pressure detection end 121. After that, the set value of P>Pg is detected by the differential pressure transmitter @ 122, and the detected signal is sent to the respective control valves 123, 12 through the flows 124, 125.
7 to operate. Desorption gas 129 is controlled by control valve 1
23 is passed through, and the stream g130; Since the desorption gas 132 uses Takaiso and Kanu, Ht SO
a.

(N Hdt 804 + ca 804, Alui is sent to the process to recover elemental am yellow etc.

On the other hand, if the operating pressure PH on the heating medium side and the operating pressure Pm on the heated side are the same or P A < P w, the heating section 103
If cracks occur in the barrier wall member, some of the desorbed gas on the heated side will diffuse to the heated side, causing I & jt
The x-agent ignites. Therefore, as mentioned above, the operating pressure of the thermal desorption regeneration tower is always set so that PM > PM.
Also, by performing gas sampling from a part of the path on the high temperature gas side and monitoring SOX &&, abnormality^111
If 11 degrees SO is detected, this indicates that a crack has occurred in the heat exchanger tube.

By monitoring S02 at 1111 degrees, it is possible to detect an abnormal situation in the heat transfer tube and prevent runaway ignition of the adsorbent. A part of the high-temperature gas is sampled from the flow 133, 5Ch (11 degrees detected, abnormal situation 11P alarm 134 detects all abnormalities and issues a warning).

The greater the differential pressure between the operating pressure Pi + on the heating medium side and the operating pressure P mu on the heated side, the faster the danger prevention and predictive response of the present invention will be. Practically preferred is about 50smAQ.

Although not shown in the embodiment shown in FIG. 1, in the thermal desorption tower 101, by supplying an inert purge gas or the like from the boundary between the heating section and the cooling section, high concentration 8 desorbed in the heating section can be removed.
0! Prevent gas from diffusing into the cooling section.

Fig. 2 shows the results of investigating the ignition situation of the adsorbent, assuming that the interlayer member (heat transfer tube) was actually torn. The measurement was carried out by heating an adsorbent made from Cory charcoal in an electric furnace to a temperature of 400C, passing N2 gas through it, and then passing O,! Switch to mixed gas A, which simulates a high temperature gas of 3%, H, 021, 5chi, Nt 76.2-, and 0! Check the temperature rise from the gas supply point. Furthermore, 0. Increase the concentration to 3.
7 well increased shi'fcHt O20.5%, N* 7
5.8% (1) Case BK lie is also shown in FIG. As is clear from the example shown in Figure 2, the adsorbent is
It is clear that by adding 00 rKfi and flowing the mixed residue A containing 13% acid J, the adsorbent is ignited, and as the temperature of the adsorbent increases, rapid combustion progresses.

According to the present invention, when an adsorbent that has adsorbed sulfur oxides is heated and desorbed, a part of the heat medium leaks to the adsorbent side during the process of indirect heating with a heat medium and heat desorption. As a method to prevent ignition, the operating pressure is always maintained lower on the heating medium side than on the adsorbent side, and the SO2 concentration is monitored by gas sampling on the heating medium side. Even if a situation such as a crack occurs in the barrier wall member (heat transfer tube), ignition of the adsorbent can be prevented. Furthermore, by monitoring the SO1 concentration through gas sampling of the heating medium, it is possible to predict 1# conditions such as cracks in barrier wall members.

[Brief explanation of drawings]

The first cause of starvation is a system diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing a test drive for ignition of adsorbent. 3... Sulfur oxide adsorbent, 7... High temperature scum circulation line, 10... Regeneration desulfurization agent, 120, 121... Pressure detection end, 106, 131... Suction blower, 102...
...High temperature gas generating powder, 123,127...Control valve, 1
03... Iis material, 101... Thermal desorption regeneration tower,
122... Differential pressure transmitter, 133... SO, m degree detection end, 134... Sow detection alarm generator. Agent Patent Attorney High & 8A ~ Far゛茅 1/ρ2 $2 Figure 3θθ 40θ 5riθ 600 degrees
(・C)

Claims (1)

[Claims] 1. When the adsorbent that has adsorbed sulfur oxides is brought into indirect contact with a heater using a heating medium and the adsorbent is thermally desorbed and regenerated, the gas operating pressure P1 on the side of the heating medium and the gas operating pressure P1 on the side of the adsorbent are Detecting the gas operating pressure Ph of the heater, and adjusting the operating pressure of the gas after desorption and the operating pressure of the circulating gas at the outlet of the heater so that the P is always higher than the Pa. A thermal desorption regeneration method characterized by