Coal gasification wet washing system

Abstract

The utility model discloses a coal gasification wet washing system, which is characterized in that a circulating pipeline is arranged between the bottom and the upper part of a washing tower, a washing tower circulating pump is arranged on the circulating pipeline, and a washing tower blowdown pipeline and a washing tower water replenishing pipeline are respectively connected on the circulating pipeline at the inlet end of the washing tower circulating pump; and a washing tower water replenishing heat exchanger is mounted on the washing tower water replenishing pipeline. According to the utility model, the outlet temperature of the washing tower is controlled by adding the water replenishing heat exchanger of the washing tower and reducing the water replenishing temperature through heat exchange of cooling water in the heat exchanger, and the input quantity of the heat exchanger can be adjusted according to the actual process condition, so that different process production conditions and load requirements can be flexibly met; and moreover, the balance between the water replenishing amount of the washing tower and the evaporation amount and the discharge capacity of the wet washing system can be maintained, the stability of the liquid level in the washing tower is ensured, the safety of subsequent equipment is greatly ensured, and the long-period safe and stable operation of the system is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of Shell coal gasification, in particular to a coal gasification wet washing system. Background Art

[0002] Shell dry powder entrained flow gasifier has many advantages such as wide adaptability to coal types and high conversion rate. Shell coal gasification process is carried out under high temperature and pressure conditions. Coal powder, oxygen and a small amount of steam flow into the gasifier under pressure and complete a series of physical and chemical processes such as heating, volatile removal, cracking, combustion and conversion in a very short time. The raw coal gas with CO and H2 as the main components formed under gasification conditions of about 1500℃ is quenched and then sent to the syngas cooler for heat recovery and cooling to the ash removal system. After removing the fly ash, the raw syngas sent to the wet scrubbing system has a temperature of about 330℃.

[0003] The wet scrubbing system is divided into a synthesis gas process and a circulating washing water process. Synthesis gas process: Synthesis gas with a temperature of about 330°C and a pressure of about 3.8MAP from the dry ash removal system enters the wet scrubber. After leaving the wet scrubber, the synthesis gas with a temperature of about 160-170°C is divided into three routes. One route is sent to the subsequent conversion process through a control valve and a cut-off valve; another route is sent to the quenching gas compressor; and the third route is sent to the synthesis gas tank for use as fuel gas. Circulating washing water process: The washing water is circulated between the bottom and the top of the scrubber through a pump and enters the scrubber through a control valve. The washing water replenishment is provided by high-pressure process water or conversion condensate and controlled by a control valve. In order to avoid the accumulation of corrosive substances and solid substances, part of the circulating water is continuously discharged from the circulation loop and sent to the preliminary water treatment system for treatment. In order to remove acidic gases such as HC1 and HF in the synthesis gas, an appropriate amount of alkali is added to the wet scrubbing system.

[0004] During the actual operation of the system, due to different types of coal, different loads, and different process operating conditions, there are problems such as reduced heat exchange effect of the synthesis gas cooler, high synthesis gas outlet temperature caused by high load operation, and reduced efficiency of the quenching gas compressor, which leads to a high temperature entering the wet washing system. As a result, the temperature out of the washing tower is high, which is easy to damage the subsequent system equipment, which is greatly not conducive to the long-term safe and stable operation of the system, and it is easy to cause the system to fail to meet high-load operation, affecting production efficiency and causing huge economic losses. Utility Model Content

[0005] The utility model aims to remedy the defects of the prior art and provide a coal gasification wet washing system.

[0006] The utility model is realized by the following technical solutions:

[0007] A coal gasification wet washing system comprises a washing tower, a circulation pipeline is arranged between the bottom and the top of the washing tower, a washing tower circulation pump is installed on the circulation pipeline, a washing tower sewage pipeline and a washing tower water replenishment pipeline are respectively connected to the inlet end of the washing tower circulation pump on the circulation pipeline, and a washing tower water replenishment heat exchanger is installed on the washing tower water replenishment pipeline.

[0008] Inlet and return water control valves are respectively provided at both ends of the washing tower water supply heat exchanger.

[0009] A bypass pipeline connected to both ends of the washing tower water supply heat exchanger is arranged on the washing tower water supply pipeline, and a bypass control valve is arranged on the bypass pipeline.

[0010] The advantages of the utility model are as follows: the utility model adds a washing tower water feed heat exchanger, inputs feed water into the washing tower water feed heat exchanger when needed, and directly feeds water to the washing tower through a bypass pipeline when not needed, and controls the washing tower outlet temperature by adding the washing tower water feed heat exchanger to lower the feed water temperature through heat exchange with cooling water in the heat exchanger, and can adjust the input amount of the heat exchanger according to actual process conditions, so as to flexibly respond to different process production conditions and load requirements, and can maintain the balance between the feed water amount of the washing tower and the evaporation amount and sewage discharge amount of the wet washing system, ensure the stability of the liquid level in the washing tower, greatly ensure the safety of subsequent equipment, and be beneficial to the long-term safe and stable operation of the system; the utility model is provided with a washing tower sewage discharge pipeline to avoid the accumulation of corrosive substances; the washing tower circulation pump of the utility model keeps the inside of the washing tower circulating between the bottom and the top, which helps the wet washing effect to reduce the temperature of the synthesizer at the washing tower outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0012] like Figure 1 As shown, a coal gasification wet washing system includes a washing tower 1, a circulation pipeline is provided between the bottom and the upper part of the washing tower 1, a washing tower circulation pump 6 is installed on the circulation pipeline, a washing tower sewage pipeline 7 and a washing tower water supply pipeline are respectively connected to the inlet end of the washing tower circulation pump 6 on the circulation pipeline, and a washing tower water supply heat exchanger 3 is installed on the washing tower water supply pipeline.

[0013] Inlet and return water control valves 4 are respectively provided at both ends of the washing tower water supply heat exchanger 3.

[0014] A bypass pipeline connected to both ends of the washing tower water supply heat exchanger 3 is provided on the washing tower water supply pipeline, and a bypass control valve 5 is provided on the bypass pipeline. When heat exchange is required, the bypass control valve 5 is closed and the inlet and return water control valve 4 is opened. When heat exchange is not required, the inlet and return water control valve 4 is closed and the bypass control valve 5 is opened.

[0015] The crude synthesis gas from the ash removal system enters the scrubber for wet washing and is sent to the subsequent process. The scrubber circulates between the bottom and the top of the scrubber through the scrubber circulation pump. The scrubber circulation has a fixed sewage discharge to avoid the accumulation of corrosive substances, and a sewage discharge pipeline is set in the scrubber circulation loop. The scrubber water replenishment in the scrubber circulation is made up of high-pressure process water or conversion condensate to maintain a stable balance between the evaporation amount and sewage level of the entire scrubber wet washing system.

[0016] During the whole process, the synthesis gas flow: the crude synthesis gas 8 from the ash removal system enters the washing tower 1 for wet washing, and exits the washing tower 1 from the top after the wet washing is completed, ensuring the synthesizer temperature at the washing tower outlet, thereby ensuring the safety of the subsequent process equipment and achieving safe and stable operation of the system.

[0017] Circulating washing water process: The washing tower 1 is maintained in balance of the liquid level by replenishing water with high pressure process water or conversion condensate in the washing tower, and the sewage is continuously discharged through the sewage pipe 7 of the washing tower to avoid the accumulation of corrosive substances and solid substances, and the washing tower high pressure process water or conversion condensate replenishment 2 is increased to reduce the temperature of the synthesis gas at the washing tower outlet 9. The washing tower circulation pump 6 keeps the washing tower circulating from the bottom and the top, which is helpful for the wet washing effect to reduce the temperature of the synthesis gas at the washing tower outlet 9. By adding a washing tower replenishment heat exchanger 3 to the washing tower high pressure process water or conversion condensate replenishment 2, according to different working conditions and requirements, the temperature of the synthesis gas at the washing tower outlet 9 is ensured to be stable within the control range, and the washing tower replenishment heat exchanger inlet and return water control valve 4 and the washing tower high pressure process water or conversion condensate replenishment bypass control valve 5 are adjusted to reduce the replenishment temperature to ensure that the temperature of the synthesis gas at the washing tower outlet 9 is stable within the control range. This control of the synthesis gas temperature at the washing tower outlet 9 can protect the safety of the equipment in the subsequent sections, and is conducive to the adjustment of the subsequent process and the high load and high efficiency production of the entire system.

Claims

1. A coal gasification wet scrubbing system, characterized in that: The invention comprises a washing tower, a circulation pipeline is arranged between the bottom and the top of the washing tower, a washing tower circulation pump is installed on the circulation pipeline, a washing tower sewage discharge pipeline and a washing tower water supply pipeline are respectively connected to the inlet end of the washing tower circulation pump on the circulation pipeline, and a washing tower water supply heat exchanger is installed on the washing tower water supply pipeline.

2. A coal gasification wet scrubbing system according to claim 1, characterized in that: Inlet and return water control valves are respectively provided at both ends of the washing tower water supply heat exchanger.

3. A coal gasification wet scrubbing system according to claim 2, characterized in that: A bypass pipeline connected to both ends of the washing tower water supply heat exchanger is arranged on the washing tower water supply pipeline, and a bypass control valve is arranged on the bypass pipeline.

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