A treatment device for removing suspended matter from grey water of a slag removal system

Abstract

The utility model discloses a kind of processing device for removing suspended solids in ash water of deslagging system, including slag pool and settling tank, it is characterized by further including pipeline mixer and flocculating agent tank, the ash water in the slag pool is transported to the settling tank by slag pool pump, and the pipeline mixer is installed on the horizontal section pipeline of ash water outlet;The flocculating agent tank contains flocculating agent, and flocculating agent is transported to the ash water inlet end of the pipeline mixer by flocculating agent pump;After the pipeline mixer is mixed, the suspended solids in the ash water form flocculation, and are transported to the settling tank and are settled and separated.Said processing device can effectively remove suspended solids in ash water of deslagging system, significantly reduce the suspended solids content of ash water in settling tank, optimize ash water quality, and ensure long-period stable operation of the device.

Description

Technical Field

[0001] This utility model belongs to the field of coal gasification technology, and relates to the treatment of ash water in slag discharge systems, and in particular to a treatment device for removing suspended solids from the ash water in slag discharge systems. Background Technology

[0002] Pulverized coal gasification technology is widely used in modern coal chemical industry due to its wide adaptability to various coal types, high carbon conversion rate, and single-furnace capacity advantage. In the gasifier, coal-water slurry undergoes a complex gasification reaction with oxygen to generate syngas. The resulting slag is cooled, solidified, and periodically discharged. The ash formed after combustion in the gasifier falls into a lock hopper at the bottom of the gasifier. The ash is then flushed into a slag pool with washing water. After sedimentation, the ash is removed by a slag remover and transported. A slag pool pump then transports the ash water from the slag pool to the ash water treatment system. The ash water system in the coal gasification unit directly affects the operation of the unit, and its main problems are as follows: 1. Impact on operational stability: Suspended solids and hardness ions in grey water are prone to scale and deposit in pipes, heat exchangers and other equipment, which can lead to reduced heat transfer efficiency and increased fluid resistance. In severe cases, it can cause pipe blockage or equipment leakage, threatening the continuous operation of the equipment.

[0003] 2. Impact on economic benefits: Deteriorating water quality shortens the lifespan of equipment, while frequent maintenance and unplanned shutdowns increase costs, and also drive up energy consumption and wastewater treatment investment.

[0004] 3. Defects in existing processes: The untreated ash water with high suspended solids content in the ash discharge system is directly discharged into the settling tank, resulting in a continuous high level of suspended solids in the tank. This causes the overflow water in the settling tank to exceed the standard and the water quality of the system to deteriorate. This has become a key technical bottleneck restricting the long-term stable operation of coal gasification units and an efficient solution is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a treatment device for removing suspended solids from the ash water in a slag discharge system. By pre-treating the ash water in the slag discharge system, the device efficiently removes suspended solids, thereby significantly reducing the suspended solids content in the ash water in the settling tank, optimizing the water quality in the settling tank, reducing scaling and corrosion of the equipment, and ensuring long-term stable operation of the device.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A treatment device for removing suspended solids from ash water in a slag discharge system includes a slag pool and a settling tank. It is characterized by further including a pipeline mixer and a flocculant tank. The ash water in the slag pool is pumped to the settling tank via a slag pool pump. The pipeline mixer is installed on a horizontal section of the pipeline at the ash water outlet. The flocculant tank contains flocculant, which is pumped to the ash water inlet of the pipeline mixer by a flocculant pump. After the ash water and flocculant are mixed in the pipeline mixer, the suspended solids in the ash water form flocs, which are then transported to the settling tank for sedimentation and separation.

[0007] The treatment device adds flocculant to the ash water and utilizes the strong turbulent flow field within the pipeline mixer to achieve instantaneous and uniform mixing of the flocculant and the ash water with high suspended solids. The charge neutralization effect of the flocculant reduces the surface charge repulsion of the suspended solids, and combined with the bridging and adsorption effect of the polymer chains, it promotes the aggregation of fine particles into large-diameter flocs, which then enter the settling tank for gravity sedimentation, significantly improving the subsequent sedimentation and separation efficiency.

[0008] Furthermore, the pipeline mixer adopts an asymmetric turbulence structure, comprising 6-8 layers of cross turbulence blades.

[0009] Furthermore, the length of the pipe between the pipe mixer and the ash water outlet is more than 15 meters to ensure the flocculation reaction time.

[0010] Furthermore, the dosage of the flocculant is controlled such that the concentration of the flocculant in the ash water after addition is in the range of 10-15 mg / L.

[0011] Furthermore, an overflow port is provided at the top of the settling tank, allowing the supernatant in the settling tank to overflow into the ash water tank.

[0012] Furthermore, a bottom flow pump is installed at the bottom of the settling tank, and the fine slurry at the bottom of the settling tank is pumped out by the bottom flow pump for subsequent dewatering treatment.

[0013] Beneficial Effects: This utility model's treatment device for removing suspended solids from ash water in a slag discharge system efficiently removes suspended solids through a pretreatment process, significantly reducing the suspended solids content in the settling tank. After adopting this new device, the suspended solids concentration in the settling tank ash water drops below 100 mg / L, significantly improving the system's ash water quality. This significant improvement in ash water quality reduces equipment maintenance costs and economic losses from unplanned shutdowns. By controlling suspended solids from entering the ash water circulation system at the source, it avoids equipment scaling, blockages, and other malfunctions, enabling long-term stable operation of the pulverized coal gasification unit and reducing downtime losses. Attached Figure Description

[0014] Figure 1 is a schematic diagram of the structure of the treatment device for removing suspended solids in the ash water of the slag discharge system of this utility model; Among them, 1. flocculant tank, 2. flocculant pump, 3. low-pressure ash water pump, 4. flocculant mixer, 5. pipeline mixer, 6. settling tank, 7. ash water tank, 8. settling tank underflow pump, 9. slag remover, 10. slag pool, 11. slag pool pump. Detailed Implementation

[0015] The technical solution of this utility model will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of this utility model.

[0016] Figure 1 This is a schematic diagram of the structure of the treatment device for removing suspended solids from ash water in the slag removal system of this utility model.

[0017] In the coal gasification process, the ash water system includes a settling tank 6 for treating black water. High-temperature black water discharged from the gasifier, etc., is concentrated through high and low pressure vacuum flash evaporation and then enters the settling tank 6. To accelerate sedimentation, flocculant is added to the settling tank 6. The flocculant is stored in a flocculant tank 1 and added to the flocculant mixer 4 via a flocculant pump 2. The black water after vacuum flash evaporation is sent to the flocculant mixer 4 by a low-pressure ash water pump 3, where it is uniformly mixed with the flocculant before entering the settling tank 6. After gravity settling, the fine slurry at the bottom of the settling tank 6 is pumped out by an underflow pump 8 and sent to a filter press system for filtration or to a centrifuge system for dewatering. The fine ash residue with reduced moisture content is transported off-site as solid waste by a slag truck. The flocculant added during the flocculation and sedimentation process of the black water is polyacrylamide.

[0018] The aforementioned treatment device for removing suspended solids from the ash water of the slag discharge system is combined with black water treatment, utilizing the principle of flocculation to treat suspended solids in the ash water of the slag discharge system. See also... Figure 1 The treatment device includes a slag pool 10. After slag removal by the slag remover 9, the slag pool 10 contains ash water with high suspended solids, which is then pumped to the settling tank 6 by the slag pool pump 11. If the ash water from the slag discharge system is directly pumped to the settling tank 6, the suspended solids will overflow into the ash water tank 7. In this invention, a pipe mixer 5 is installed on the horizontal section of the ash water outlet pipe. Simultaneously, flocculant from the flocculant tank 1 is pumped by the flocculant pump 2 to the ash water inlet end of the pipe mixer 5. After the ash water and flocculant are mixed in the pipe mixer 5, the suspended solids in the ash water form flocs, which then enter the settling tank 6 for sedimentation and separation.

[0019] The aforementioned treatment device for removing suspended solids from ash water in the slag discharge system includes the following steps in its application process: (1) Slag pool pretreatment stage: The black water generated by slag discharge enters the slag pool 10. After static sedimentation, the solid slag is removed by the slag removal machine 9.

[0020] (2) Pipeline mixing enhancement stage: The ash water in the slag pool 10 is transported to the outlet horizontal pipe section through the slag pool pump 11. A static pipeline mixer 5 (with multiple cross mixing units inside) is installed in this section. At the same time, the agent in the flocculant tank 1 is injected into the inlet end of the pipeline mixer 5 through the flocculant pump 2. The turbulence effect in the pipeline is used to achieve uniform mixing of the agent and ash water, which promotes the formation of dense flocs of suspended matter.

[0021] (3) Solid-liquid separation stage: The flocculated ash water enters the settling tank 6 for gravity settling. After the supernatant meets the standard, it flows into the ash water tank 7 for reuse. The high-concentration sludge at the bottom of the settling tank 6 is transported to the centrifuge system by the bottom flow pump 8 of the settling tank, and the sludge is dewatered by centrifugal force.

[0022] (4) Operation and maintenance: Continuously monitor the concentration of suspended solids in the ash water at the overflow outlet of settling tank 6, dynamically adjust process parameters based on monitoring data, and regularly maintain the dosing system equipment.

[0023] The key equipment and technical parameters of the treatment device for removing suspended solids from the ash water in the slag discharge system include the following aspects: 1. Pipe mixer 5: adopts a static mixing unit with an internal asymmetric turbulence structure design, and is equipped with 6-8 layers of cross turbulence blades. The pipe diameter is DN200. 2. Equipment Installation: Select a suitable location on the horizontal straight pipe section at the outlet of slag tank pump 11 to install the pipeline mixer 5. Ensure that the pipeline mixer 5 is concentrically connected to the pipeline and reliably sealed. The installation location should be controlled within 15-20 meters from the inlet pipeline of settling tank 6 to ensure sufficient flocculation reaction time. Simultaneously modify the flocculant dosing pipeline, precisely setting the dosing point at the inlet end of the pipeline mixer 5 to ensure that the flocculant is immediately and evenly mixed with the ash water after injection.

[0024] 3. Parameter control: The flocculant dosage is adjusted in real time according to the grey water flow rate and suspended solids concentration. The flocculant concentration in the grey water is controlled within the range of 10-15 mg / L (which can be dynamically optimized according to the actual water quality). Precise dosing is achieved through the frequency conversion adjustment of flocculant pump 2 to ensure the best reaction ratio between the agent and the grey water.

[0025] The application of the aforementioned treatment device for removing suspended solids from ash water in the slag discharge system produces the following effects: 1. Technically: After treatment by this process, the concentration of suspended solids in the ash water in the settling tank is reduced to below 100mg / L, which is significantly improved compared to before the equipment was modified (the concentration of suspended solids in the ash water in the settling tank was above 200mg / L).

[0026] 2. Economic benefits: The significant improvement in greywater quality reduces equipment maintenance costs and economic losses caused by unplanned shutdowns. At the same time, through precise control of flocculant dosing, flocculant consumption is reduced by 15%-20% compared to the original level.

[0027] 3. Operation: Controlling suspended solids from the source to enter the ash water circulation system avoids equipment scaling, blockage and other malfunctions, achieving long-term stable operation of the pulverized coal gasification unit and reducing downtime losses.

[0028] This new invention provides a solution for the treatment of high suspended solids ash water in the ash discharge system of a coal gasification unit, and is particularly suitable for low-cost technical transformation of ash discharge systems of various coal gasification technologies such as Shell and GSP.

Claims

1. A treatment device for removing suspended solids from ash water in a slag discharge system, comprising a slag pool and a settling tank, characterized in that, It also includes a pipeline mixer and a flocculant tank. The ash water in the slag pool is pumped to the settling tank by a slag pool pump. The pipeline mixer is installed on the horizontal section of the pipeline at the ash water outlet. The flocculant tank contains flocculant, which is pumped to the ash water inlet of the pipeline mixer by a flocculant pump. After the ash water and flocculant are mixed in the pipeline mixer, the suspended matter in the ash water forms flocs, which are then transported to the settling tank for sedimentation and separation.

2. The treatment device for removing suspended solids from ash water in a slag discharge system according to claim 1, characterized in that, The aforementioned pipe mixer adopts an asymmetric turbulence structure, containing 6-8 layers of cross turbulence blades.

3. The treatment device for removing suspended solids from ash water in a slag discharge system according to claim 1, characterized in that, The length of the pipe between the pipe mixer and the grey water outlet is more than 15 meters.

4. The treatment device for removing suspended solids from ash water in a slag discharge system according to claim 1, characterized in that, The dosage of the flocculant is controlled so that the concentration of the flocculant in the ash water after addition is within the range of 10-15 mg / L.

5. The treatment device for removing suspended solids from ash water in a slag discharge system according to claim 1, characterized in that, An overflow port is provided at the top of the settling tank, and the supernatant in the settling tank overflows into the ash water tank.

6. The treatment device for removing suspended solids from ash water in a slag discharge system according to claim 1, characterized in that, A bottom flow pump is installed at the bottom of the settling tank, and the fine slurry at the bottom of the settling tank is pumped out by the bottom flow pump.

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