Fly ash-based filling material slurry, and preparation method and application thereof
By adjusting the specific surface area of fly ash and the molecular weight of polyether polyol, a gel network is formed, which solves the problem of suspension stability of fly ash-based filling slurry under long-distance transportation and static conditions, and achieves long-term suspension stability and good transportability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TAIYUAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-04-09
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies cannot maintain the long-term suspension stability of fly ash-based filling slurry under long-distance transportation and static conditions, leading to particle sedimentation and segregation, which affects performance and engineering quality.
By controlling the specific surface area of fly ash and the number-average molecular weight of polyether polyol, an immobilized layer and gel network are formed, thereby achieving the dispersion and suspension stability of fly ash particles and inhibiting agglomeration and sedimentation.
The prepared fly ash-based filling slurry maintains good suspension stability and consistent viscosity before and after settling, exhibiting long-term suspension stability and is suitable for pipeline transportation and settling storage.
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Figure CN122255702A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fluid transport engineering technology, specifically relating to a fly ash-based filling slurry, its preparation method, and its application. Background Technology
[0002] Fly ash, as a major solid waste generated by coal-fired power plants, is of great significance for environmental protection and sustainable development due to its large-scale resource utilization. Preparing fly ash into a slurry with organic matter for pipeline transportation is a key technological step towards achieving efficient, low-cost, and long-distance transport. Compared to traditional vehicle transportation, pipeline transportation offers significant advantages such as strong continuity, high efficiency, low cost, and minimal environmental impact.
[0003] However, the slurry transported through pipelines is essentially a solid-liquid suspension system, and fly ash particles are highly susceptible to settling, stratification, and segregation under gravity. In pipeline systems with long distances, large diameters, or complex operating conditions such as pump stoppages and speed changes, settling particles can cause siltation and blockage at the bottom of the pipeline, significantly increasing pumping resistance and energy consumption, and even posing a risk of pipe bursts. Segregation leads to uneven distribution of slurry concentration and composition along the pipeline or across the cross-section, severely affecting its performance and engineering quality upon arrival at the terminal, such as uneven strength and performance fluctuations in the filling material. Therefore, ensuring that the slurry maintains suspension stability throughout the entire transportation process, especially under dynamic start-up and shutdown conditions and flow rate changes, is the core of achieving safe and reliable pipeline transportation.
[0004] Current technologies primarily focus on improving the dynamic suspension stability of slurries during transport by adding thickeners or optimizing gradation, but they pay insufficient attention to long-term suspension stability under static conditions after transport. In many practical engineering applications, especially at the end of long-distance transport or in intermittent operation sites, the slurry, after being pumped to the point of use, often cannot undergo sufficient secondary mixing due to limitations such as site space, equipment conditions, operational timeliness, or cost control. In such cases, it is required that the slurry maintain good suspension stability after leaving the transport pipeline system, and even during a period of static storage, to avoid the inability to be directly pumped or used due to rapid particle settling and caking. Existing slurry suspension stabilization technologies often focus on short-term suspension stability or rely on vigorous mixing before use to restore homogeneity, failing to achieve long-term suspension stability without pre-mixing conditions.
[0005] Therefore, there is an urgent need to develop a fly ash-based filling slurry with good long-term suspension stability that can be used immediately upon delivery. Summary of the Invention
[0006] The purpose of this invention is to provide a fly ash-based filling slurry, its preparation method, and its application. The fly ash-based filling slurry provided by this invention exhibits good long-term suspension stability.
[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a fly ash-based filling slurry, comprising the following components by weight: 20-360 parts fly ash, 10-100 parts polyether polyol; the fly ash has an average specific surface area of 13-25 m². 2 / g; the number average molecular weight of the polyether polyol is 600~2000.
[0008] Preferably, the average specific surface area of the fly ash is 14.5~24 m². 2 / g.
[0009] Preferably, the polyether polyol is one or more of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and glycerol-polypropylene glycol triol.
[0010] Preferably, the fly ash-based filling slurry comprises the following components by mass: 20-100 parts fly ash and 50-100 parts polyether polyol.
[0011] Preferably, the fly ash-based filling slurry comprises the following components by mass: 20-90 parts fly ash and 70-100 parts polyether polyol.
[0012] Preferably, the fly ash-based filling slurry further includes the following components in parts by weight: 0.2 to 2.0 parts of catalyst, 3 to 30 parts of flame retardant, 0 to 10 parts of antistatic agent, and 0.1 to 5 parts of defoamer.
[0013] Preferably, the fly ash has one or more of the following morphologies: spherical, porous, flaky, and blocky.
[0014] The present invention also provides a method for preparing the fly ash-based filling slurry described in the above technical solution, comprising: mixing all components to obtain the fly ash-based filling slurry.
[0015] Preferably, the mixing is carried out under stirring conditions; the stirring speed is 200~500 r / min, and the stirring time is 40~52 h.
[0016] The present invention also provides the application of the fly ash-based filling slurry described in the above technical solution or the fly ash-based filling slurry prepared according to the preparation method described in the above technical solution in fly ash pipeline transportation.
[0017] This invention provides a fly ash-based filling slurry, comprising the following components by weight: 20-360 parts fly ash and 10-100 parts polyether polyol; wherein the fly ash has an average specific surface area of 13-25 m². 2 / g; the number average molecular weight of the polyether polyol is 600~2000. In the fly ash-based filling slurry of the present invention, the hydroxyl groups of the polyether polyol are adsorbed onto the surface of the fly ash through hydrogen bonding or coordination to form an immobilized layer. The percolation of the immobilized layer forms a gel network, achieving dispersion and suspension stability of the fly ash particles, inhibiting agglomeration and sedimentation of the fly ash particles, and obtaining a filling slurry with good long-term suspension stability; by controlling the average specific surface area of the fly ash to 13~25m²... 2 The method of controlling the number average molecular weight of the polyether polyol to be 600-2000 allows for greater adsorption of polyether polyols on the fly ash surface, which is beneficial for improving suspension stability. By controlling the number average molecular weight of the polyether polyol to be 600-2000, the lower number average molecular weight polyether polyol contains more terminal hydroxyl groups for the same mass, resulting in more hydroxyl groups fixed on the fly ash surface and a denser immobilized layer, which is beneficial for improving the long-term suspension stability of the fly ash-based filling slurry. Experimental results show that the fly ash-based filling slurry prepared by this invention exhibits a sol-gel transition within the test range, forming a gelled three-dimensional network structure with good suspension stability. The viscosity of the prepared fly ash-based filling slurry remains basically consistent before and after standing, demonstrating long-term suspension stability. Its low viscosity also indicates good pipeline transportability. Attached Figure Description
[0018] Figure 1 The images show the dynamic strain scanning diagrams of the fly ash-based filling slurries prepared in Examples 1-6 of this invention. Figure 2 The images show dynamic strain scans of the fly ash-based filling slurries prepared in Comparative Examples 1-3 of this invention. Detailed Implementation
[0019] This invention provides a fly ash-based filling slurry, comprising the following components by weight: 20-360 parts fly ash and 10-100 parts polyether polyol; wherein the fly ash has an average specific surface area of 13-25 m². 2 / g; the number average molecular weight of the polyether polyol is 600~2000.
[0020] The fly ash-based filling slurry provided by this invention comprises 20-360 parts of fly ash, preferably 20-100 parts, and more preferably 20-90 parts, by weight. In one embodiment of this invention, the fly ash may specifically be 20 parts, 40 parts, 50 parts, 70 parts, or 90 parts. In this invention, fly ash serves as the matrix component of the filling slurry.
[0021] In this invention, the average specific surface area of the fly ash is 13~25m². 2 / g, preferably 14.5~24m 2 / g; As one embodiment of the present invention, the average specific surface area of the fly ash can be 14.63m². 2 / g, 14.77m 2 / g, or 16.83m 2 / g, or 17.01m 2 / g, or 17.19m 2 / g, can also be 23.43m 2 / g. By controlling the specific surface area of fly ash within the above-mentioned range, this invention allows for the adsorption of more polyether polyols on the surface of fly ash, which is beneficial for improving suspension stability.
[0022] In this invention, the morphology of the fly ash is preferably one or more of spherical, porous, flake, and block shapes, more preferably multiple of spherical, porous, flake, and block shapes. As one embodiment of this invention, the morphology of the fly ash can be flake-shaped, block-shaped, flake-porous, flake-shaped and spherical, block-shaped and porous, or block-shaped and spherical. When the fly ash has multiple morphologies, this invention does not have special requirements for the proportion of fly ash with various morphologies, as long as the average specific surface area of the fly ash is within the required range. In an embodiment of this invention, the specific surface area of the flake-shaped fly ash is 23.43 m². 2 / g, the specific surface area of the blocky fly ash is 16.83m². 2 / g, the specific surface area of the porous fly ash is 12.19m². 2 / g, the specific surface area of the spherical fly ash is 11.87m². 2 / g. Spherical fly ash (glass microspheres) has a ball-bead effect, which makes fly ash-based filling slurry easier to transport; porous fly ash (porous / honeycomb fly ash) has strong adsorption capacity, which is conducive to achieving non-settling; blocky fly ash (irregular fragmented / angular fly ash) particles can interlock with each other, which can improve the strength during application; flaky fly ash (flaky / layered fly ash) can form a layered structure, which can improve the stability of the slurry; the gradation of fly ash with various morphologies can further optimize the performance of fly ash-based filling slurry.
[0023] Based on 20-360 parts by weight of fly ash, the fly ash-based filling slurry provided by this invention comprises 10-100 parts of polyether polyol, preferably 50-100 parts, and more preferably 70-100 parts. As one embodiment of this invention, the polyether polyol may specifically be 10 parts, 30 parts, 50 parts, 60 parts, 70 parts, or 100 parts. In this invention, the hydroxyl groups of the polyether polyol are adsorbed onto the surface of the fly ash through hydrogen bonding or coordination to form an immobilized layer. The percolation of the immobilized layer forms a gel network, achieving dispersion and suspension stability of the fly ash particles, inhibiting agglomeration and sedimentation of the fly ash particles, and facilitating the obtaining of a filling slurry with good long-term suspension stability.
[0024] In this invention, the number average molecular weight of the polyether polyol is 600-2000, preferably 600-1500, and more preferably 600-1000. Polyether polyols with lower number average molecular weights per unit mass contain more terminal hydroxyl groups, resulting in more hydroxyl groups fixed on the fly ash surface and a denser immobilized layer. Using polyether polyols with a number average molecular weight within the above range is beneficial for improving the long-term suspension stability of fly ash-based filling slurry.
[0025] In this invention, the polyether polyol is preferably one or more of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and glycerol-polypropylene glycol triol; as one embodiment of this invention, the polyether polyol may be polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, or glycerol-polypropylene glycol triol.
[0026] Based on a mass fraction of 20-360 parts of fly ash, the fly ash-based filling slurry provided by this invention preferably further includes 0.2-2.0 parts of catalyst. As one embodiment of this invention, the catalyst may specifically be 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.4 parts, 1.6 parts, 1.9 parts, or 2.0 parts. As another embodiment of this invention, the catalyst may specifically be one or more of dibutyltin dilaurate, diethyltin dicarboxylate, butyllithium, isobutyllithium, ethylenediamine, and isopropylamine or isotin octoate. The addition of the above catalyst facilitates the direct use of the fly ash-based filling slurry after it leaves the conveying pipeline system.
[0027] Based on a mass fraction of 20-360 parts of fly ash, the fly ash-based filling slurry provided by this invention preferably further includes 3-30 parts of flame retardant. In one embodiment of this invention, the flame retardant can specifically be 3 parts, 4 parts, 6 parts, 10 parts, 15 parts, 18 parts, 22 parts, or 30 parts. In another embodiment of this invention, the flame retardant can be an organophosphorus flame retardant; specifically, it can be tris(1-chloro-2-propyl) phosphate, triisopropylphenyl phosphate, organophosphorus halogenated flame retardant Doher-6209, organophosphorus halogenated flame retardant LD-301, or organophosphorus halogenated flame retardant HY-313. The addition of the above flame retardants can inhibit spontaneous combustion and ensure the safe pipeline transportation of the fly ash-based filling slurry.
[0028] Based on a mass fraction of 20-360 parts of fly ash, the fly ash-based filling slurry provided by this invention preferably further includes 0-10 parts of an antistatic agent. As one embodiment of this invention, the antistatic agent may specifically be 0, 1, 3, 6, 7, 8, 9, or 10 parts. As another embodiment of this invention, the antistatic agent may specifically be tris(β-chloroethyl) phosphate, alkyl tertiary amine phosphate, alkyl tertiary amine sulfate, alkyl tertiary amine nitrate, cationic antistatic agent MY-216C, or stearoyltrimethylammonium chloride. The addition of the above-mentioned antistatic agents can eliminate the generation of electric sparks from static electricity accumulation, ensuring the safe pipeline transportation of the fly ash-based filling slurry.
[0029] Based on 20-360 parts by weight of fly ash, the fly ash-based filling slurry provided by this invention preferably further includes 0.1-5 parts of defoamer. In one embodiment of this invention, the defoamer may specifically be 0.1 parts, 1 part, 3 parts, or 5 parts. In another embodiment of this invention, the defoamer may specifically be organosilicon defoamer BYK-066N or organosilicon defoamer MY-210. The addition of the above-mentioned defoamer helps to eliminate harmful air bubbles inside the fly ash-based filling slurry and improves its fluidity.
[0030] The fly ash-based filling slurry provided by this invention can suppress the agglomeration and sedimentation of fly ash particles by controlling the composition and dosage of each component, resulting in a filling slurry with good long-term suspension stability and ensuring the safety of pipeline transportation of the fly ash-based filling slurry.
[0031] The present invention also provides a method for preparing the fly ash-based filling slurry described in the above technical solution, comprising: mixing all components to obtain the fly ash-based filling slurry.
[0032] The present invention does not have any special limitation on the source of raw materials for each component used; commercially available raw materials or those prepared according to methods known in the art are acceptable.
[0033] In this invention, the mixing is preferably carried out under stirring conditions; the stirring speed is preferably 200~500 r / min, and the stirring time is preferably 40~52 h. In an embodiment of this invention, the mixing is carried out at 25°C using magnetic stirring, the stirring speed is 300 r / min, and the stirring time is 48 h.
[0034] In this invention, the fly ash-based filling slurry is preferably pressed into a cylinder and sealed at room temperature.
[0035] The fly ash-based filling slurry prepared by the above method has good long-term suspension stability.
[0036] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0037] Example 1 Fly ash-based filling slurry: Composed of the following components by mass: flaky fly ash (specific surface area 23.43 m²). 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 100 parts of polypropylene glycol with a number average molecular weight of 600, 0.2 parts of dibutyltin dilaurate catalyst, 3 parts of tri(1-chloro-2-propyl) phosphate flame retardant, 1 part of tri(β-chloroethyl) phosphate antistatic agent, and 1 part of organosilicon defoamer BYK-066N. Preparation method of fly ash-based filling slurry: Weigh each component according to the mass fraction, mix all components at 25℃ using magnetic stirring at a speed of 300 r / min for 48 h. The sample after stirring is uniform and free of visible particles. After obtaining the fly ash-based filling slurry, press it into a material cylinder under pressure and seal it at room temperature for storage.
[0038] Example 2 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "polypropylene glycol with a number average molecular weight of 600" in Example 1 is replaced with "polypropylene glycol with a number average molecular weight of 1000". The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0039] Example 3 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "lumpy fly ash (specific surface area of 16.83m²)". 2 50 parts of ( / g) and porous fly ash (specific surface area of 12.19m²) 2 / g) 40 parts" (the average specific surface area of fly ash is 14.77m²) 2 / g); The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0040] Example 4 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "lumpy fly ash (specific surface area of 16.83m²)". 2 50 parts of ( / g) and spherical fly ash (specific surface area of 11.87m²) 2 / g) 40 parts (the average specific surface area of fly ash is 14.63m²) 2 / g)”; The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0041] Example 5 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "Flake fly ash (specific surface area of 23.43m³)". 2 40 parts of ( / g) and porous fly ash (specific surface area of 12.19m²) 2 50 parts (g) of fly ash (the average specific surface area of fly ash is 17.19 m²) 2 / g)”; The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0042] Example 6 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "Flake fly ash (specific surface area of 23.43m³)". 2 40 parts of ( / g) and spherical fly ash (specific surface area of 11.87m²) 2 50 parts ( / g) of fly ash (the average specific surface area of fly ash is 17.01m²) 2 / g)”; The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0043] Comparative Example 1 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "spherical fly ash (specific surface area of 11.87m²)".2 / g) 90 parts (the average specific surface area of fly ash is 11.87m²) 2 / g)”; The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0044] Comparative Example 2 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "flaky fly ash (specific surface area of 23.43 m²)" used in Example 1 is replaced with... 2 / g) 90 parts (the average specific surface area of fly ash is 23.43m²) 2 Replace " / g)" with "porous fly ash (specific surface area of 12.19m³)". 2 / g) 90 parts (the average specific surface area of fly ash is 12.19m²) 2 / g)”; The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0045] Comparative Example 3 The only difference between this and the fly ash-based filling slurry of Example 1 is that the "polypropylene glycol with a number average molecular weight of 600" in Example 1 is replaced with "polypropylene glycol with a number average molecular weight of 3000". The preparation method of fly ash-based filling slurry is the same as in Example 1.
[0046] Dynamic rheological testing under strain control was used to conduct rheological tests on the fly ash-based filling slurries prepared in Examples 1-6 and Comparative Examples 1-3. The dynamic strain scan diagrams of the fly ash-based filling slurries in Examples 1-6 under dynamic scanning were obtained as follows: Figure 1 As shown, the dynamic strain scan diagrams of the fly ash-based filling slurries in Comparative Examples 1-3 under dynamic scanning are as follows: Figure 2 As shown.
[0047] from Figure 1 It can be seen that Examples 1-6 all exhibited sol-gel transitions within the test range; from Figure 2 It can be seen that Comparative Examples 1-3 all exhibited a sol state within the test range. This indicates that the fly ash-based filling slurries prepared in Examples 1-6 of this invention form a gelled three-dimensional network structure and possess good suspension stability.
[0048] The viscosity of the fly ash-based filling slurries prepared in Examples 1-6 and Comparative Examples 1-3 was tested using a rotational viscometer, as well as the viscosity of the upper and lower slurries after standing for 15 days. The viscosity test data before and after standing are shown in Table 1.
[0049] Table 1. Viscosity test data of fly ash-based filling slurry before and after standing.
[0050] As can be seen from Table 1, the fly ash-based filling slurries of Examples 1-6 maintained good homogeneity during the standing time, and no obvious phase separation or particle sedimentation occurred, indicating that the long-term suspension stability of the fly ash-based filling slurries was good; while obvious phase separation and particle sedimentation occurred in Comparative Examples 1-3.
[0051] The compressive strength of the fly ash-based filling slurries prepared in Examples 1-6 and Comparative Examples 1-3 was tested using the uniaxial compressive strength test method (GB / T 50081) after being cured with isocyanate curing agent at a 1:1 mass ratio before and after standing. The compressive strength test data of the slurries prepared before and after standing for 15 days are shown in Table 2.
[0052] Table 2. Compressive strength test data of fly ash-based filling slurry specimens after curing before and after standing.
[0053] As can be seen from Table 2, the compressive strength of the slurry specimens did not decrease significantly after standing, but was slightly improved; the compressive strength of the fly ash-based filling slurry specimens with two different fly ash morphologies was significantly improved compared with the fly ash-based filling slurry specimens with a single morphology.
[0054] As can be seen from the above embodiments, the fly ash-based filling slurry prepared by the present invention forms a gelled three-dimensional network structure and has good suspension stability; the viscosity and compressive strength of the fly ash-based filling slurry prepared before and after standing are basically the same, and it has long-term suspension stability.
[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A fly ash-based filling slurry, comprising, by weight parts: 20-360 parts fly ash and 10-100 parts polyether polyol; wherein the fly ash has an average specific surface area of 13-25 m². 2 / g; the number average molecular weight of the polyether polyol is 600~2000.
2. The fly ash-based filling slurry according to claim 1, characterized in that, The average specific surface area of the fly ash is 14.5~24 m². 2 / g.
3. The fly ash-based filling slurry according to claim 1, characterized in that, The polyether polyol is one or more of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and glycerol-polypropylene glycol triol.
4. The fly ash-based filling slurry according to claim 1, characterized in that, By weight, it includes the following components: 20-100 parts fly ash and 50-100 parts polyether polyol.
5. The fly ash-based filling slurry according to claim 4, characterized in that, By weight, it includes the following components: 20-90 parts fly ash and 70-100 parts polyether polyol.
6. The fly ash-based filling slurry according to any one of claims 1 to 5, characterized in that, It also includes the following components in parts by weight: catalyst 0.2 to 2.0 parts, flame retardant 3 to 30 parts, antistatic agent 0 to 10 parts, and defoamer 0.1 to 5 parts.
7. The fly ash-based filling slurry according to claim 1, characterized in that, The fly ash has one or more of the following morphologies: spherical, porous, flaky, and blocky.
8. A method for preparing the fly ash-based filling slurry according to any one of claims 1 to 7, comprising: All components are mixed to obtain fly ash-based filling slurry.
9. The preparation method according to claim 8, characterized in that, The mixing is preferably carried out under stirring conditions; the stirring speed is 200~500 r / min, and the stirring time is 40~52 h.
10. The application of the fly ash-based filling slurry according to any one of claims 1 to 7 or the fly ash-based filling slurry prepared according to the preparation method of claim 8 or 9 in fly ash pipeline transportation.