Intermediate pump accumulated acid treatment system of alkylation device

Abstract

The utility model relates to treatment of waste sulfuric acid generated in an intermediate pump flow in an alkylation process, in particular to an alkylation device intermediate pump accumulated acid treatment system which comprises an alkylation reactor, a feeding pipeline is arranged at an inlet of the alkylation reactor, the alkylation reactor is connected to an acid settler through a pipeline, and the acid settler is connected to a water inlet of the alkylation reactor. The acid settler is connected with a flash tank through a pipeline, the bottom of the flash tank is connected with an intermediate pump unit through a pipeline, and the intermediate pump unit is connected to a sulfuric acid refining system; the bottom of the intermediate pump unit is connected with an acid discharge tank through an acid discharge pipeline; the downstream of the acid discharge tank is sequentially connected with a waste acid storage tank and a waste acid cracking furnace system through pipelines; according to the scheme, on the basis of original equipment and pipelines, an acid discharge process is added between the intermediate pump and the acid discharge tank, so that stored acid stored in the standby pump can be regularly discharged into the acid discharge tank, the quality of sewage in the neutralization tank is improved, and the problem of accumulation of dirty oil and combustible gas in underground pipelines and the neutralization tank is solved.

Description

Technical Field

[0001] The utility model relates to the treatment of waste sulfuric acid generated in an intermediate pump process in an alkylation process, in particular to an acid accumulation treatment system for an intermediate pump of an alkylation device. Background Art

[0002] In the process of petroleum refining, C4 alkylation is an important process in refinery gas processing, mainly used to produce high-octane gasoline blending components. C4 alkylation unit refers to an industrial facility that generates alkylate oil mainly composed of isooctane by reacting isobutane and butene under the action of a catalyst. The characteristic of sulfuric acid alkylation reaction is that the reaction products will carry waste sulfuric acid and sulfate esters. Part of these waste sulfuric acid and sulfate esters will enter the flash tank with the alkylate oil product. An acid collection tank is set at the bottom of the flash tank to collect part of the waste sulfuric acid. A trace amount of waste sulfuric acid will enter the downstream sulfuric acid refining unit with the intermediate pump. There are two intermediate pumps. The spare pump will accumulate waste sulfuric acid due to the lack of material circulation, which will cause overload when the pump is started. Therefore, sulfuric acid needs to be discharged to the neutralization tank through an underground pipeline. However, the waste acid contains acid-soluble oil and isobutane. Discharging it to the neutralization tank will cause problems such as excessive COD of sewage and accumulation of combustible gas in the underground sewage pipeline and neutralization tank. Utility Model Content

[0003] In view of the above-mentioned technical problems, the present invention improves the intermediate pump process and changes the acid discharge process of the standby pump to solve the environmental pollution and safety hazards caused by the discharge of waste acid.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is: an acid accumulation treatment system for an intermediate pump of an alkylation unit, comprising: an alkylation reactor, a feed pipeline is provided at the inlet of the alkylation reactor, the alkylation reactor is connected to an acid settler through a pipeline, the acid settler is connected to a flash tank through a pipeline, the bottom of the flash tank is connected to an intermediate pump unit through a pipeline, and the intermediate pump unit is connected to a sulfuric acid refining system; the bottom of the intermediate pump unit is connected to an acid discharge tank through an acid discharge pipeline, and the downstream of the acid discharge tank is connected to a waste acid storage tank and a waste acid cracking furnace system through pipelines in sequence;

[0005] Further, the feed line originates from the mixed C4 feed device;

[0006] Furthermore, the intermediate pump unit includes two parallel operating pumps and a standby pump, a pipeline is drawn from the bottom of the flash tank and branched to the inlet of the operating pump and the standby pump, and the outlet pipelines of the operating pump and the standby pump are gathered together and connected to the sulfuric acid refining system;

[0007] Furthermore, a running pump inlet valve and a running pump outlet valve are respectively arranged before and after the running pump; a standby pump inlet valve and a standby pump outlet valve are respectively arranged before and after the standby pump;

[0008] Furthermore, the acid discharge pipeline is a pipeline drawn from the bottom of the standby pump and connected to the acid discharge tank; the acid discharge pipeline includes: an acid discharge pipeline, a sight glass and a gate valve; a pump bottom valve is arranged on the acid discharge pipeline close to the standby pump, a sight glass is arranged on the acid discharge pipeline close to the acid discharge tank, and a gate valve is arranged at the front end of the sight glass close to the inlet of the acid discharge tank;

[0009] In the above-mentioned acid discharge pipeline, the sight glass is added to observe whether the waste acid in the standby pump is discharged cleanly, and the added gate valve is used to control the discharge flow and cut off the logistics.

[0010] Furthermore, the acid discharge pipeline is made of SS316.

[0011] Furthermore, one side of the acid discharge tank is connected to an acid re-settler through a pipeline, and the acid settler is connected to the acid re-settler through a pipeline; after sedimentation and separation in the acid settler, the material can enter the acid re-settler through the pipeline for re-sedimentation.

[0012] Furthermore, an acid discharge pump is provided on the pipeline between the acid discharge tank and the waste acid storage tank, and the acid discharge pump pumps the waste acid in the acid discharge tank into the waste acid storage tank;

[0013] Furthermore, a waste acid pump is provided on the pipeline between the waste acid storage tank and the waste acid cracking furnace system, and the waste acid in the waste acid storage tank is pumped into the waste acid cracking furnace system by the waste acid pump to recover sulfur.

[0014] The mixed C4 enters the alkylation reactor from the feed pipeline, and reaches the acid settler after the reaction in the alkylation reactor. The waste acid generated in the acid settler enters the flash tank. The acid in the flash tank flows into the intermediate pump unit and is deposited in the standby pump. The acid stored in the standby pump is regularly discharged into the closed container acid discharge tank through the acid discharge pipeline, and is sent to the waste acid cracking furnace system to recover sulfur element through the acid discharge pump, waste acid storage tank, and waste acid pump.

[0015] The specific acid removal steps of the above structure are:

[0016] When the operating pump is started, open the outlet valve of the standby pump, close the inlet valve of the standby pump, open the pump bottom valve of the standby pump and the gate valve of the acid discharge pipeline respectively, and use the alkylate oil mixture circulating in the operating pump to flush the waste acid in the standby pump body. During operation, pay attention to the standby pump outlet valve not being opened too large, and control the standby pump pressure at 0.2~0.3MPa.

[0017] The flushed waste acid and oil products settle and separate in the acid discharge tank, the gaseous hydrocarbons evaporate and are sent to the flare system, the liquid acid settles at the bottom of the acid discharge tank and is sent to the waste acid storage tank, while the liquid hydrocarbons float on the top of the acid; thus, all the waste acid and hydrocarbons are treated in a closed space.

[0018] The above process of this scheme is essentially to utilize the high outlet pressure of the running pump to discharge the waste acid of the standby pump into the acid discharge tank through the added acid discharge pipeline.

[0019] The beneficial effects of the technical solution of the utility model are:

[0020] This solution is based on the original equipment and pipelines. By adding an acid discharge process between the intermediate pump and the acid discharge tank, the acid accumulated in the standby pump can be discharged into the acid discharge tank regularly, thereby improving the quality of the wastewater in the neutralization tank and solving the problem of accumulation of dirty oil and combustible gas in underground pipelines and neutralization tanks. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the structural diagram of the acid accumulation treatment system of the intermediate pump of the alkylation unit of the utility model.

[0022] In the figure, 1, mixed C4 feeding device, 2, alkylation reactor 3, acid settler 4, flash tank 5, operating pump 6, standby pump 7, sulfuric acid refining system 8, sight glass 9, acid re-settler 10, acid discharge tank 11, acid discharge pump 12, waste acid storage tank 13, waste acid pump 14, waste acid cracking furnace system, 15, acid discharge pipeline 16, gate valve. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0024] like Figure 1 The illustrated system for treating acid accumulation in an intermediate pump of an alkylation unit comprises: an alkylation reactor 2, wherein a feed pipeline is provided at the inlet of the alkylation reactor 2, the alkylation reactor 2 is connected to an acid settler 3 through a pipeline, the acid settler 3 is connected to a flash tank 4 through a pipeline, the bottom of the flash tank 4 is connected to an intermediate pump unit through a pipeline, and the intermediate pump unit is connected to a sulfuric acid refining system 7; the bottom of the intermediate pump unit is connected to an acid discharge tank 10 through an acid discharge pipeline, and the downstream of the acid discharge tank 10 is connected to a waste acid storage tank 12 and a waste acid cracking furnace system 14 through pipelines in sequence;

[0025] Among them, the feed pipeline originates from the mixed C4 feed device 1;

[0026] The intermediate pump unit includes two parallel operating pumps 5 and standby pumps 6. A pipeline is drawn from the bottom of the flash tank 4 and branched to the inlets of the operating pump 5 and the standby pump 6. The outlet pipelines of the operating pump 5 and the standby pump 6 are gathered together and connected to the sulfuric acid refining system 7.

[0027] The running pump 5 is provided with a running pump inlet valve and a running pump outlet valve at the front and rear, respectively; the standby pump 6 is provided with a standby pump inlet valve and a standby pump outlet valve at the front and rear, respectively;

[0028] The acid discharge pipeline is a pipeline drawn from the bottom of the standby pump 6 and connected to the acid discharge tank 10; the acid discharge pipeline includes: an acid discharge pipeline 15, a sight glass 8 and a gate valve 16; the acid discharge pipeline 15 is provided with a pump bottom valve near the standby pump 6, the acid discharge pipeline 15 is provided with a sight glass 8 near the acid discharge tank 10, and the front end of the sight glass 8 is provided with a gate valve 16 near the inlet of the acid discharge tank 10;

[0029] In the above-mentioned acid discharge pipeline, the sight glass 8 is added to observe whether the waste acid in the standby pump 6 is discharged cleanly, and the added gate valve 16 is used to control the discharge flow and cut off the logistics.

[0030] The material of the acid discharge pipeline 15 is SS316.

[0031] One side of the acid discharge tank 10 is also connected to an acid re-settler 9 through a pipeline, and the acid settler 3 and the acid re-settler 9 are connected through a pipeline; after sedimentation and separation in the acid settler 3, the material can enter the acid re-settler 9 through the pipeline for re-settlement.

[0032] An acid discharge pump 11 is provided on the pipeline between the acid discharge tank 10 and the waste acid storage tank 12, and the acid discharge pump 11 pumps the waste acid in the acid discharge tank 10 into the waste acid storage tank 12;

[0033] A waste acid pump 13 is provided on the pipeline between the waste acid storage tank 12 and the waste acid cracking furnace system 14, and the waste acid pump 13 pumps the waste acid in the waste acid storage tank 12 into the waste acid cracking furnace system 14 to recover sulfur.

[0034] The mixed C4 enters the alkylation reactor 2 from the feed pipeline, and reaches the acid settler 3 after the reaction in the alkylation reactor 2. The waste acid generated in the acid settler 3 enters the flash tank 4. The acid in the flash tank 4 flows into the intermediate pump unit and is deposited in the standby pump 6. The acid stored in the standby pump 6 is regularly discharged into the closed container acid discharge tank 10 through the acid discharge pipeline 15, and is sent to the waste acid cracking furnace system 14 through the acid discharge pump 11, the waste acid storage tank 12, and the waste acid pump 13 to recover the sulfur element;

[0035] The specific acid removal steps of the above structure are:

[0036] When the running pump 5 is started, open the outlet valve of the standby pump, close the inlet valve of the standby pump, open the pump bottom valve of the standby pump and the sewage gate valve 16 of the acid discharge pipeline 15, and use the alkylate oil mixture flowing in the running pump 5 to flush the waste acid in the standby pump 6. During operation, pay attention to the standby pump outlet valve not being opened too much, and control the pressure of the standby pump 6 at 0.2~0.3MPa.

[0037] As another embodiment of the utility model, the alkylation unit in which the utility model is located is also equipped with a waste acid treatment system, which can save the natural gas consumption of the waste acid unit.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

Claims

1. An acid accumulation treatment system for an intermediate pump of an alkylation unit, characterized in that: include: An alkylation reactor, wherein a feed pipeline is provided at the inlet of the alkylation reactor, the alkylation reactor is connected to an acid settler through a pipeline, the acid settler is connected to a flash tank through a pipeline, the bottom of the flash tank is connected to an intermediate pump unit through a pipeline, and the intermediate pump unit is connected to a sulfuric acid refining system; the bottom of the intermediate pump unit is connected to an acid discharge tank through an acid discharge pipeline, and the downstream of the acid discharge tank is connected to a waste acid storage tank and a waste acid cracking furnace system through pipelines in sequence.

2. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 1, characterized in that: The intermediate pump unit includes two parallel operating pumps and a standby pump. A pipeline is drawn from the bottom of the flash tank and branched to the inlets of the operating pump and the standby pump. The outlet pipelines of the operating pump and the standby pump are gathered together and connected to the sulfuric acid refining system.

3. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 2, characterized in that: An operating pump inlet valve and an operating pump outlet valve are respectively arranged before and after the operating pump; a standby pump inlet valve and a standby pump outlet valve are respectively arranged before and after the standby pump.

4. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 1, characterized in that: The acid discharge pipeline is a pipeline drawn out from the bottom of the standby pump and connected to the acid discharge tank; the acid discharge pipeline includes: an acid discharge pipeline, a sight glass and a gate valve; a pump bottom valve is arranged on the acid discharge pipeline close to the standby pump, a sight glass is arranged on the acid discharge pipeline close to the acid discharge tank, and a gate valve is arranged at the front end of the sight glass close to the entrance of the acid discharge tank.

5. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 4, characterized in that: The material of the acid discharge pipeline is SS316.

6. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 1, characterized in that: One side of the acid discharge tank is also connected to an acid re-settler through a pipeline, and the acid settlers are connected to the acid re-settlers through pipelines.

7. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 1, characterized in that: An acid discharge pump is arranged on the pipeline between the acid discharge tank and the waste acid storage tank, and the acid discharge pump pumps the waste acid in the acid discharge tank into the waste acid storage tank.

8. The acid accumulation treatment system for the intermediate pump of the alkylation unit according to claim 1, characterized in that: A waste acid pump is arranged on the pipeline between the waste acid storage tank and the waste acid cracking furnace system, and the waste acid in the waste acid storage tank is pumped into the waste acid cracking furnace system by the waste acid pump.

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