阅读说明：本技术 一种lpg常温干法脱硫净化工艺 (L PG normal-temperature dry desulfurization purification process ) 是由 王泽� 张先茂 王天元 王国兴 王瑜 郑敏 赵志杰 陈凯 金建涛 于 2020-05-13 设计创作，主要内容包括：本发明公开了一种LPG常温干法脱硫净化工艺。LPG经过水洗后,依次经过三个脱硫净化反应器,分别脱除其中的Cl、F、H<Sub>2</Sub>S、RHS、单质S及其他硫化物,可以彻底解决铜片腐蚀不合格的问题。该工艺在常温下操作,整个工艺无升温降温过程,没有蒸汽和冷却水的消耗,同时该工艺投资成本低,不需要制氢及精馏设备,并可做成撬装装置,特别适合在中小炼厂应用。(The invention discloses a L PG normal temperature dry desulfurization purification process, L PG is washed by water and sequentially passes through three desulfurization purification reactors to respectively remove Cl, F and H in the PG 2 S, RHS, simple substance S and other sulfides, can thoroughly solve the problem of unqualified corrosion of the copper sheet. The process is operated at normal temperature, the whole process has no temperature rise and temperature reduction process, no consumption of steam and cooling water, low investment cost, no need of hydrogen production and rectification equipment, skid-mounted devices and is particularly suitable for small and medium-sized refineries.)

1. An L PG normal temperature dry desulfurization purification process is characterized by comprising the following steps:

⑴ the raw material is first washed in water washing tower to eliminate alcohol, aldehyde and ether from L PG, and then fed into reactor A from bottom to top to eliminate H from the raw material₂S, Cl and F, wherein a desulfurizer is filled in the reactor A, and the desulfurizer is a Fe-Ca system and a Ni-Ca system;

⑵ the L PG purified by the reactor A enters the reactor B from top to bottom, and RHS in the reactor B is O₂And the catalyst are converted into corresponding RSSR to achieve the aim of removing mercaptan, and the catalyst is filled in the reactor B;

⑶ the L PG purified by the reactor B enters the reactor C, wherein the high efficiency adsorbent is filled in the reactor C, the adsorbent can adsorb simple substance S, RSSR and other sulfides, the L PG purified by the reactor C is a qualified product, and the product does not contain Cl, F and H₂S, RSH, simple substance S and other impurities, and the copper sheet is qualified in corrosion.

2. The L PG normal temperature dry desulfurization purification process of claim 1, wherein 50-500ppm of hydroxyethyl hexahydro-s-triazine is added into the washing water in the step ⑴.

3. The normal-temperature dry desulfurization purification process of L PG as claimed in claim 1, wherein in the step ⑴, the desulfurizing agent in the reactor A is filled in two layers, by volume, the lower 2/3 bed layer is filled with Fe-Ca system desulfurizing agent, the upper 1/3 bed layer is filled with Ni-Ca system desulfurizing agent, wherein Fe and Ni are gamma-FeOOH and NiCO respectively₃·2Ni(OH)₂·4H₂The form of O exists.

4. The L PG normal temperature dry desulfurization purification process as claimed in claim 1 or 3, wherein Ca in the desulfurizer Fe-Ca system and Ni-Ca system is nano CaCO₃The compound reacts with Cl and F to generate corresponding salt, thereby achieving the aim of removing Cl and F.

5. The L PG normal temperature dry desulfurization purification process of claim 1, wherein in step ⑵, the catalyst in the reactor B is filled in two layers, by volume, the upper 1/3 bed layer is filled with Al-Cu catalyst, and the lower 2/3 bed layer is filled with C-Zn catalyst.

6. The L PG normal temperature dry desulfurization purification process of claim 1 or 5, wherein the Al-Cu catalyst is Al₂O₃The catalyst is a carrier, CuO is used as an active component, the C-Zn catalyst is a tar carbon carrier, and binuclear phthalocyanine zinc ammonium sulfonate is used as an active component.

7. The L PG normal temperature dry desulfurization purification process of claim 1, wherein the high efficiency adsorbent in the reactor C in the step ⑶ is filled in two layers, the upper layer 1/2 is filled with silica as a carrier and Na by volume₂PbO₂The Si-Pb efficient adsorbent is prepared by packing Ti-NH with titanium oxide as carrier and triethanolamine as active component in lower 1/2 bed layer₃Is a high-efficiency adsorbent.

8. The L PG normal temperature dry desulfurization purification process of claim 1, wherein the lower part of the reactor A is provided with a water diversion and guide shower, and water brought by a water washing device is discharged at regular time.

9. The L PG normal temperature dry desulfurization purification process as claimed in claim 1, wherein 10-100ppm of O is supplemented into the inlet of the reactor B₂Or air.

10. The L PG normal temperature dry desulfurization purification process of claim 9, wherein the oxygen or air supplemented in the reactor B is mixed with L PG by a Venturi mixer.

Technical Field

The invention relates to a L PG normal-temperature dry desulfurization purification process, belonging to the field of petrochemical industry.

Background

L PG has unqualified copper sheet corrosion due to high content of impurities such as sulfur, chlorine and the like, and influences the next use of the PG, and researches show that alcohol, aldehyde, ether, Cl, F and H₂S, RHS and over high content of simple substance S, which is the main reason of disqualification of copper sheet corrosion, therefore, desulfurization purification is the premise of L PG utilization, the current L PG desulfurization technology includes dry desulfurization and wet desulfurization, the wet desulfurization mostly adopts fiber membrane desulfurization, the process firstly uses alkali washing or amine liquid to remove hydrogen sulfide, then enters the fiber membrane process to convert mercaptan into sodium mercaptide, enters alkali liquor through extraction, and then carries out alkali liquor regeneration, the process is complex, the device has large floor area and high investment, which is not beneficial to popularization in small and medium-sized devices₂S, RHS, there are various acidic substances, such as simple substance S, etc., and the existence of simple substance S and acid is the main reason why the conventional dry desulphurization cannot solve the problem of qualified corrosion of copper sheets. Therefore, a dry desulfurization process which has the advantages of low investment and simple process flow and can thoroughly solve the corrosion of the copper sheet needs to be developed.

Application number 201410336427.9 discloses a L PG deep desulfurization process method, which comprises the following steps of removing H from ⑴ liquefied gas by an amine liquid extraction tower₂S, then the liquid enters a settling tank of a water washing tower for liquid-liquid separation, amine liquid carried by L PG is removed, ⑵ liquefied gas and H₂The mixture enters a sulfur conversion reactor to convert sulfur into sulfide with high boiling point, ⑶ is rectified with L PG and the sulfide with high boiling point, the process needs a reactor with the temperature of 100 ℃ and 280 ℃ and the pressure of 0.2-2.0MPa, the energy consumption and the investment are large, and H is also needed₂The requirements on equipment and the whole plant area are relatively high, and the method is not suitable for being applied to small and medium-scale refineries.

Application number 201410782329.8 discloses a L PG deep desulfurization combined process, which adopts a COS water washing tower to remove H in L PG respectively₂S and COS, wherein small molecular weight mercaptan in L PG is converted into high boiling point mercaptan by an oxidation towerThe sulfur content of L PG is reduced to below 5 mug/g by a rectification method, and the invention needs to use the rectification method to remove the sulfide, so the production and investment costs are increased, the process is complex, and the invention is not suitable for small and medium-sized refineries.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a dry desulfurization purification process, which is operated at normal temperature, has no temperature rise and temperature reduction process in the whole process, has no consumption of steam and cooling water, has low investment cost, does not need hydrogen production and rectification equipment, can be made into a skid-mounted device, is particularly suitable for L PG desulfurization purification of small and medium refineries, and completely solves the problem of unqualified copper sheet corrosion.

The invention is realized by the following technical scheme:

⑴ the raw material is first washed in water washing tower to eliminate alcohol, aldehyde and ether from L PG, and then fed into reactor A from bottom to top to eliminate H from the raw material₂S, Cl and F, wherein a desulfurizer is filled in the reactor A, and the desulfurizer is a Fe-Ca system and a Ni-Ca system;

⑵ the L PG purified by the reactor A enters the reactor B from top to bottom, and RHS in the reactor B is O₂And the reaction product is converted into corresponding RSSR under the action of catalyst to reach the aim of eliminating mercaptan, and the reactor B is filled with catalyst.

⑶ the L PG purified by the reactor B enters the reactor C, wherein the high efficiency adsorbent is filled in the reactor C, the adsorbent can adsorb simple substance S, RSSR and other sulfides, the L PG purified by the reactor C is a qualified product, and the product does not contain Cl, F and H₂S, RSH, simple substance S and other impurities, and the copper sheet is qualified in corrosion.

50-500ppm of hydroxyethyl hexahydro-s-triazine is added into the washing water.

The desulfurizer in the reactor A is filled in two layers, wherein the lower 2/3 bed layer is filled with Fe-Ca system desulfurizer, the upper 1/3 bed layer is filled with Ni-Ca system desulfurizer, and Fe and Ni are respectively gamma-FeOOH and NiCO₃·2Ni(OH)₂·4H₂The form of O exists.

The desulfurizer Fe-Ca system and Ni-Ca systemThe Ca in the calcium carbonate is nano CaCO₃The compound reacts with Cl and F to generate corresponding salt, thereby achieving the aim of removing Cl and F;

the catalyst in the reactor B is filled in two layers, wherein an upper layer 1/3 bed layer is filled with Al-Cu catalyst, and a lower layer 2/3 bed layer is filled with C-Zn catalyst.

The Al-Cu catalyst is Al₂O₃The catalyst is a carrier, CuO is used as an active component, the C-Zn catalyst is a tar carbon carrier, and binuclear phthalocyanine zinc ammonium sulfonate is used as an active component.

The high-efficiency adsorbent in the reactor C is filled in two layers, and the upper layer 1/2 contains silicon oxide as a carrier and Na by volume₂PbO₂The Si-Pb efficient adsorbent is prepared by packing Ti-NH with titanium oxide as carrier and triethanolamine as active component in lower 1/2 bed layer₃Is a high-efficiency adsorbent.

The lower part of the reactor A is provided with a water diversion and guide shower, and the water brought by the water washing device is discharged at regular time.

The inlet of the reactor B is supplemented with 10-100ppm of O₂Or air.

The oxygen or air supplemented into the reactor B is mixed with L PG through a Venturi mixer.

The invention has the beneficial effects that:

⑴ A small amount of hydroxyethyl hexahydro-s-triazine is added into the washing water, which has high solubility to alcohol, aldehyde and ether, and can improve the removal rate of alcohol, aldehyde and ether substances by the washing water, and meanwhile, the hydroxyethyl hexahydro-s-triazine can be naturally decomposed, thus being an environment-friendly and pollution-free substance.

⑵ the bottom of the reactor A is provided with a guide shower, the gas enters from the bottom and goes out from the top, the water brought by the water washing device can be separated, a gas-water separation device is saved, and the investment cost of the device is reduced to the maximum extent.

⑶ grading filling of desulfurizer in reactor, such as 2/3 Fe-Ca desulfurizer at the bottom of reactor A and 1/3Ni-Ca desulfurizer at the top, wherein the price of Ni-Ca desulfurizer is higher, about 5 times of the price of Fe-Ca desulfurizer, but its sulfur capacity is low, the desulfurization precision is good, the price of Fe-Ca desulfurizer is low, but its sulfur capacity is high, but the desulfurization precision is poor.

⑷ the gamma-FeOOH in the desulfurizing agent contains-OH, which can accelerate H₂S is adsorbed on the surface, and the sulfur capacity of the S is obviously higher than that of common Fe₂O₃，NiCO₃·2Ni(OH)₂·4H₂The unique molecular structure of O can increase the binding capacity of Ni and S, and remove hydrogen sulfide to less than 10ppb, thereby obviously improving the desulfurization precision; nano CaCO₃Has extremely fine crystal grains and high specific surface area, and can effectively remove acid substances such as Cl, F and the like while desulfurizing after being mixed with Fe or Ni compounds.

⑸ the process comprises washing with water to remove alcohol, ether, aldehyde and acid, which may react and convert into acid during the subsequent storage of L PG, and contain trace amount of O in L PG₂And also needs to be supplemented with appropriate amount of O when converting RHS₂In the removal of H₂While S, H inevitably occurs₂S+O₂=S+H₂O reaction, so that partial S is generated, and H can be removed by the common dry desulfurization process₂S and RHS are removed, but generated simple substances are ignored, the simple substance S is just another important reason that the copper sheet is not qualified in corrosion, and the process of the invention is used for removing H₂And the acid and the simple substance S can be removed while the S and the RSH are simultaneously removed, so that the problem that the copper sheet is not qualified in corrosion is thoroughly solved.

⑹ the process of the invention is operated at normal temperature, the process flow is simple, no steam and cooling water are consumed, no complex MDEA desulfurization and regeneration device is needed, the investment and operation cost is low, no alkali slag is discharged, and the invention is environment-friendly and pollution-free.

Drawings

FIG. 1 is a flow chart of L PG normal temperature dry desulfurization purification process.

In the figure, 1 is raw material L PG, 2 is L PG feed pump, 3 is washing water, 4 is washing tower, 5 is guide shower, 6 is Fe-Ca desulfurizer, 7 is Ni-Ca desulfurizer, 8 is oxygen or air, 9 is Venturi mixer, 10 is Al-Cu catalyst, 11 is C-Zn catalyst, 12 is Ti-NH₃Is a high-efficiency adsorbent, 13 is a Si-Pb high-efficiency adsorbent.

Examples

The invention is described in further detail below with reference to the figures and specific examples, which are provided by way of illustration only and should not be construed to limit the scope of the invention.