Process for preparing solid potassium formate by concentrating potassium formate solution with hot carrier of yellow phosphorus tail gas

Abstract

The present application relates to yellow phosphorus chemical technology field, specifically to a kind of yellow phosphorus tail gas heat carrier concentrated potassium formate solution preparation solid potassium formate process, first potassium formate solution is sent into heating pot, then yellow phosphorus tail gas is used as fuel to heat organic heat carrier, and high-temperature heat carrier is transported to the coil in heating pot by closed circuit circulation mode, and the solution is indirectly heated and concentrated;Concentrated liquid is transported to the surface of rotary cooling drum again, and is cooled and crystallized at the surface temperature of 20 DEG C-50 DEG C, forms the crystalline layer of predetermined thickness, finally is scraped down by scraper device, and solid potassium formate product is obtained.By using yellow phosphorus tail gas as heat source, waste is treated with waste and energy recovery is realized;Through organic heat carrier closed circuit circulation and accurate temperature control, the problems of high energy consumption and high cost of traditional electric heating process are solved, and the inconvenience of traditional water agent product storage and transportation is effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of yellow phosphorus chemical technology, and in particular to a process for preparing solid potassium formate by concentrating potassium formate solution from yellow phosphorus tail gas using a heat carrier. Background Technology

[0002] Potassium formate is an important environmentally friendly chemical with wide applications in oil drilling, agricultural fertilizers, and other fields. In the oil drilling industry, solid potassium formate serves as a high-quality solids-free drilling fluid inhibitor, effectively preventing formation mud formation and stabilizing the wellbore. In agriculture, as a non-chloride potassium source, it can improve soil structure and increase crop yield and quality, thus leading to continuous growth in market demand.

[0003] Currently, potassium formate is commonly produced using a process of electrically heating and concentrating the potassium formate solution followed by crystallization. This process suffers from high energy consumption and high production costs, hindering large-scale industrial production. Furthermore, potassium formate is typically in aqueous form, presenting numerous inconveniences in transportation and storage: airtight packaging is required to prevent leakage, increasing packaging costs; compared to solid form, aqueous solutions are larger in volume and weight, significantly increasing transportation costs, especially for long-distance or large-volume transport; and in some cases, temperature control equipment is necessary to prevent product deterioration, further increasing the complexity and cost of transportation. Therefore, the existing process is not only economically unsound but also limits its market promotion and ease of application due to the product's form.

[0004] On the other hand, the production of yellow phosphorus chemicals generates a large amount of yellow phosphorus tail gas. This tail gas is often emitted directly without effective utilization, resulting in energy waste and potential environmental pollution, which is inconsistent with the requirements of a green circular economy and current national environmental protection policies. In summary, existing technologies lack an integrated process that can effectively utilize yellow phosphorus tail gas as an energy source, reduce energy consumption and costs in potassium formate production, and directly produce solid potassium formate products that are easy to store and transport. How to achieve the resource utilization of yellow phosphorus tail gas and combine it with energy-saving potassium formate production has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier. This process solves the problems of high energy consumption in potassium formate production, energy waste and environmental pollution caused by direct emission of yellow phosphorus tail gas, and inconvenience in storage and transportation of products from traditional processes in the prior art.

[0006] To achieve the above objectives, the present invention provides a process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier, comprising the following steps:

[0007] Pump the qualified potassium formate solution into the high-level tank, and then let it flow naturally into the heating pot;

[0008] Yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier is driven by a circulation pump and enters the coil in the heating pot for closed-loop circulation to indirectly heat the potassium formate solution in the pot, causing the water in it to evaporate and concentrate.

[0009] Concentrated potassium formate liquid is fed to the surface of a rotary cooling drum. The cooling water circulation system is started, and the surface temperature of the rotary cooling drum is controlled at 20℃~50℃, so that the potassium formate liquid cools and crystallizes on the drum surface to form a crystal layer. By adjusting the feed speed, drum speed and cooling water temperature, the thickness of the crystal layer is controlled to 3mm. When the crystal layer reaches the predetermined thickness, it is scraped off the drum surface by a scraper device to obtain solid potassium formate product.

[0010] In this process, yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot to evaporate and concentrate the water. Specifically, this includes:

[0011] By controlling the combustion conditions of the yellow phosphorus tail gas and the circulation flow rate of the organic heat carrier, the concentration temperature of the potassium formate solution is controlled at 200℃~250℃.

[0012] In this process, yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot to evaporate and concentrate the water. Specifically, this includes:

[0013] The heating pot is provided with an insulation cover, which is fitted onto the outer wall of the heating pot and forms an isolation space between the heating pot and the heating pot.

[0014] The process includes activating the cooling water circulation system and controlling the surface temperature of the rotating cooling drum to 20℃~50℃, allowing potassium formate liquid to cool and crystallize on the drum surface to form a crystalline layer. Specifically, this includes:

[0015] The cooling water circulation system includes a chiller unit and a cooling circulation tower, which are used to maintain a constant cooling water temperature.

[0016] Once the crystalline layer reaches a predetermined thickness, it is scraped off the surface of the drum by a scraper device to obtain solid potassium formate, which specifically includes:

[0017] The scraper device includes a stainless steel scraper, the angle of which and its position close to the roller surface are adjustable.

[0018] In this process, yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot to evaporate and concentrate the water. Specifically, this includes:

[0019] The combustion device of the organic heat carrier boiler is configured to fully combust the yellow phosphorus tail gas, and the generated high-temperature flue gas exchanges heat with the organic heat carrier in the boiler through radiation and convection.

[0020] This also includes:

[0021] The obtained solid potassium formate product is in the form of flaky crystals with a purity of over 96%.

[0022] This invention discloses a process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier. First, the potassium formate solution is fed into a heating pot. Then, yellow phosphorus tail gas is used as fuel to heat an organic heat carrier. The high-temperature heat carrier is then transported to a coil inside the heating pot via a closed-loop circulation system for indirect heating and concentration of the solution. The concentrated liquid is then transported to the surface of a rotary cooling drum, where it is cooled and crystallized at a surface temperature of 20°C to 50°C, forming a crystalline layer of a predetermined thickness. Finally, the crystals are scraped off using a scraper device to obtain the solid potassium formate product. By utilizing yellow phosphorus tail gas as a heat source, waste-to-waste treatment and energy recovery are achieved. The closed-loop circulation of the organic heat carrier and precise temperature control solve the problems of high energy consumption and high cost associated with traditional electric heating processes. Furthermore, the rotary cooling and scraping forming technology directly yields a flaky solid product with a purity higher than 96%, effectively overcoming the inconvenience of storage and transportation of traditional aqueous products, achieving multiple benefits including energy saving, environmental protection, and product form optimization. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0024] Figure 1 This is a flowchart of the process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas heat carrier according to the present invention. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0026] Please see Figure 1 This invention provides a process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier, comprising the following steps:

[0027] S101: Pump the qualified potassium formate solution into the high-level tank, and then let it flow naturally into the heating pot;

[0028] Specifically, firstly, the intermediate potassium formate solution from the upstream process undergoes online quality testing to ensure it is "qualified." The key indicators for qualification include: potassium formate concentration (usually the initial process concentration, such as 30%-50%), impurity ion content (such as chloride and sulfate ions must be below a specific threshold), pH value, and suspended solids content, all of which meet the requirements for subsequent concentration and crystallization. The qualified solution is then introduced into a raw material storage tank.

[0029] Subsequently, a corrosion-resistant centrifugal pump (such as a fluoroplastic alloy pump) is used to pump the solution from the temporary storage tank to the elevated tank. The discharge port at the bottom of the elevated tank maintains a certain height difference (typically 3-8 meters) relative to the inlet of the downstream heating pot. This height difference creates a hydrostatic head, which drives the solution to "naturally flow in." The volume of the elevated tank is designed according to the system's processing capacity, typically for 1-2 hours of solution processing, to ensure continuous system operation during brief maintenance or fluctuations of the feed pump.

[0030] During operation, a level gauge (such as a radar level gauge or a glass tube level gauge) installed on the elevated tank is interlocked with the raw material pump to achieve automatic control of the liquid level in the tank, maintaining the liquid level within a set range (e.g., 50%-80%). When the liquid level falls below the lower limit, the raw material pump automatically starts to replenish the liquid; when the upper limit is reached, pumping stops. This control method ensures the stability of material supply to subsequent processes.

[0031] The solution flows out from the bottom of the elevated tank and "naturally" into the heating pot through the feed pipe. This process is gravity-driven, requiring no additional conveying power, which not only saves energy but, more importantly, avoids the flow pulsations and shear forces that might occur with a feed pump, resulting in an extremely stable material flow into the heating pot. A manual regulating valve and flow meter (such as an electromagnetic flow meter) are installed on the feed pipe to precisely set and monitor the initial feed rate into the heating pot, which is matched to the subsequent concentration rate and evaporation intensity.

[0032] By using the "high-level tank buffer + gravity flow" design, the intermittent pumping is transformed into continuous and stable natural feeding, providing stable material input conditions for the subsequent concentration process that requires precise temperature control. This is a prerequisite for the smooth, efficient and controllable operation of the entire process.

[0033] S102: Yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier is driven by a circulation pump and enters the coil in the heating pot for closed-loop circulation to indirectly heat the potassium formate solution in the pot, so that the water in it evaporates and concentrates.

[0034] Specifically, the first step is the pretreatment and stable supply of yellow phosphorus tail gas. The tail gas from the yellow phosphorus electric furnace (mainly containing components such as CO, H2, PH3, and H2S) first enters the purification system. This system typically includes water washing, alkaline washing, and deep desulfurization and dephosphorization units to remove harmful impurities such as dust, fluorides, sulfides, and phosphides, obtaining clean fuel gas with stable calorific value that meets combustion requirements. The purified yellow phosphorus tail gas is then transported to the burner of a specially designed organic heat carrier boiler via a Roots blower or compressor, after passing through a flame arrester and a pressure stabilizing tank.

[0035] Secondly, there is the efficient conversion and transfer of heat energy. The organic heat carrier boiler is a special type of boiler that uses organic heat carrier (heat transfer oil) as the heat transfer medium. The purified yellow phosphorus tail gas is fully mixed with combustion air and burned in the boiler burner to produce high-temperature flue gas. The heat of the high-temperature flue gas is not directly used to heat the process materials, but is transferred to the organic heat carrier in the boiler in two ways: 1) Radiative heat transfer: The high-temperature flame and the inner wall of the furnace strongly radiate heat the organic heat carrier in the coil; 2) Convection heat transfer: The high-temperature flue gas flows in the boiler's convective heating surface (smoke tubes or finned tubes), transferring heat to the organic heat carrier through convection. After sufficient heat exchange, the organic heat carrier is heated to a set high temperature (e.g., 280-320℃). Subsequently, under the forced drive of a high-temperature circulating pump (such as an air-cooled high-temperature hot oil pump), the high-temperature organic heat carrier is transported to the downstream heating pot through insulated pipes.

[0036] The heating pot is equipped with multiple sets of spiral or U-shaped coils, which form part of the closed-loop circulation loop of the organic heat carrier. High-temperature organic heat carrier from the boiler flows through these coils immersed in potassium formate solution, achieving stable indirect heat exchange with the solution inside the pot through the coil walls. This heat exchange method avoids direct contact between the fuel gas and the process materials, ensuring product purity, and offers a large heat exchange area and high efficiency. The coil design fully considers fluid mechanics and heat transfer, ensuring uniform flow of the heat carrier within the coils without dead zones, thereby achieving uniform and gentle heating of the solution throughout the pot.

[0037] Under continuous and stable heating, the water in the potassium formate solution is constantly evaporated, and the solution concentration gradually increases until the desired supersaturation or predetermined concentration endpoint is reached (which can be monitored by an online densitometer or refractometer). During this process, the water vapor generated by evaporation is discharged through the exhaust port at the top of the heating pot and can be recovered or treated by condensation.

[0038] Finally, a linkage control strategy was adopted: the combustion intensity (heat load) was controlled by adjusting the regulating valve on the yellow phosphorus tail gas inlet pipe and the damper of the combustion fan; simultaneously, the speed of the high-temperature circulating pump was adjusted by the frequency converter to change the circulation flow rate of the organic heat carrier in the coil. The heat carrier temperature at the boiler outlet and the solution temperature in the heating pot are key monitoring parameters. A cascade or feedforward-feedback control loop is constructed through a DCS or PLC control system to dynamically adjust combustion and circulation, overcoming potential fluctuations in the calorific value of the yellow phosphorus tail gas and ensuring that the concentration temperature remains stable within the optimal process window. Excessively high temperatures (>250℃) may cause partial decomposition of potassium formate or localized overheating of the solution, resulting in turbidity; excessively low temperatures (<200℃) result in a slow evaporation rate, relatively increased energy consumption, and a higher risk of excessive moisture content in the final product. Therefore, 200℃~250℃ is the optimal concentration temperature control.

[0039] By constructing an indirect, closed-loop heat transfer chain of "yellow phosphorus tail gas → organic heat carrier → potassium formate solution", not only is the waste heat of industrial waste gas utilized safely and efficiently, realizing "waste treatment", but also, with its precisely controllable heating method, it solves the technical problems of high energy consumption, uneven temperature, and crude control of traditional direct electric heating or open flame heating methods, laying a solid foundation for obtaining high-quality solid products in the future.

[0040] S103: Concentrate qualified potassium formate liquid and convey it to the surface of a rotary cooling drum. Start the cooling water circulation system and control the surface temperature of the rotary cooling drum to 20℃~50℃, so that the potassium formate liquid cools and crystallizes on the drum surface to form a crystal layer. By adjusting the feed speed, drum speed and cooling water temperature, control the thickness of the crystal layer to 3mm. When the crystal layer reaches the predetermined thickness, it is scraped off the drum surface by a scraper device to obtain solid potassium formate product.

[0041] Specifically, when the density or concentration of the potassium formate solution in the concentrator reaches the preset "qualified" standard (for example, a density of approximately 1.58 g / cm³, or reaching a supersaturated state), it is considered "qualified concentrated potassium formate liquid". At this time, the liquid material, which is in a molten or highly viscous state, is guided to the rotary cooling drum through the bottom discharge valve (usually an insulated jacket valve) via an insulated conveying pipe (to prevent premature crystallization and blockage during the conveying process).

[0042] The concentrate is conveyed by a high-temperature resistant screw pump or gear pump (ensuring stable delivery of high-viscosity materials). Before entering the drum, a flow meter and regulating valve are installed on the pipeline, interlocked with the pump speed to achieve precise and stable control of the feed rate. The concentrate is guided to a distributor (usually a slotted or overflow weir type) located above the rotating cooling drum. The distributor's function is to spread the high-temperature liquid evenly and continuously across the entire working width of the drum, forming an initial thin liquid film. Uniform distribution is a prerequisite for obtaining a consistently thick crystalline layer.

[0043] Meanwhile, the cooling water circulation system has been started and is operating. This system is a closed-loop system, mainly consisting of a chiller unit (or refrigeration unit), a fiberglass cooling tower, a circulating water pump, and a jacket or spiral flow channel installed inside the drum. The cooling water circulates in the system, and its temperature is regulated by the cooling power of the chiller unit and the heat dissipation capacity of the cooling tower, and is precisely maintained within the range of 20℃ to 50℃. The setting of this temperature range is crucial: if the temperature is too low (<20℃), it may lead to excessively rapid cooling, high internal stress in the crystallized layer, easy cracking, and a surge in cooling system energy consumption; if the temperature is too high (>50℃), the cooling driving force is insufficient, the crystallization speed is slow, and it may result in an excessively soft crystallized layer or failure to form.

[0044] Rotary cooling drums are typically made of stainless steel and contain constant-temperature cooling water. When the drum, whose surface is uniformly covered with a high-temperature potassium formate liquid film, begins to rotate, a drastic temperature difference is generated between the low-temperature surface of the drum (maintained at 20-50℃) and the high-temperature liquid film. The potassium formate in the liquid film becomes supersaturated due to rapid cooling, and then heterogeneous nucleation and growth begin on the surface of the drum, forming a continuous crystalline layer.

[0045] Precise control of the crystalline layer thickness (reaching 3mm) is achieved through the coordinated adjustment of multiple parameters:

[0046] Feed rate: This determines the amount of material supplied to the surface of the drum per unit time. A faster feed rate results in more material available for crystallization, leading to a thicker crystal layer.

[0047] Drum rotation speed: This determines the residence time (cooling time) of the material on the drum surface. Slower rotation speed results in a longer residence time, more thorough cooling, and a thicker crystal layer; higher rotation speed has the opposite effect.

[0048] Cooling water temperature directly affects cooling intensity and crystallization kinetics. Lower water temperature results in greater cooling intensity, faster crystallization rate, and a thicker crystal layer within the same residence time.

[0049] In practice, the three parameters (feed speed, drum speed, and cooling water temperature) are controlled in a linked PID manner through a DCS system. The system uses the target thickness of the crystallized layer (3mm) as the setpoint and feedback from an online thickness gauge (such as a laser thickness gauge) as the process variable. It dynamically adjusts the feed pump frequency, drum drive motor frequency, and chiller set temperature to achieve automatic, precise, and stable control of the crystallized layer thickness. Maintaining a thickness of approximately 3mm is the result of optimization that comprehensively considers scraping efficiency, product strength, cooling efficiency, and subsequent packaging requirements.

[0050] As the drum continues to rotate, the crystalline layer gradually solidifies under cooling and reaches the preset mechanical strength. The crystallization process is complete when the drum reaches the position of the scraper device. The core of the scraper device is a high-strength, high-hardness, corrosion-resistant stainless steel scraper. This scraper is installed via a precision adjustment mechanism, allowing for fine-tuning of its angle (the angle between the scraper blade and the drum surface) and its position close to the drum surface (the blade gap). This precise adjustment ensures that the scraper can cleanly and completely scrape the entire 3mm thick crystalline layer off the drum surface without excessively abrading it. Due to its brittleness, the scraped-off solid potassium formate breaks into appropriately sized flakes or fragments during its descent, falling into the collection hopper or conveyor belt below for subsequent packaging.

[0051] The final solid potassium formate product is a light-colored flaky crystal. Through this strictly controlled process, its purity is maintained at over 96%, fully meeting the application requirements of high-end drilling fluids and special fertilizers.

[0052] In summary, the integrated continuous operation of the "rotary cooling scraper" replaces the traditional intermittent crystallization, centrifugation, drying, and pulverization processes. This not only significantly shortens the process and improves production efficiency but also directly produces a solid product with low moisture content, minimal clumping, and uniform specifications. It perfectly solves the industry problems of high storage and transportation costs and inconvenience associated with liquid products mentioned in existing technologies. The entire system operates smoothly and controllably, which is a crucial guarantee for the industrial production of high-quality solid potassium formate using this process.

[0053] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier, characterized in that, Includes the following steps: Pump the qualified potassium formate solution into the high-level tank, and then let it flow naturally into the heating pot; Yellow phosphorus tail gas is used as fuel and burned in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier is driven by a circulation pump and enters the coil in the heating pot for closed-loop circulation to indirectly heat the potassium formate solution in the pot, causing the water in it to evaporate and concentrate. Concentrated potassium formate liquid is fed to the surface of a rotary cooling drum. The cooling water circulation system is started, and the surface temperature of the rotary cooling drum is controlled at 20℃~50℃, so that the potassium formate liquid cools and crystallizes on the drum surface to form a crystal layer. By adjusting the feed speed, drum speed and cooling water temperature, the thickness of the crystal layer is controlled to 3mm. When the crystal layer reaches the predetermined thickness, it is scraped off the drum surface by a scraper device to obtain solid potassium formate product.

2. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Using yellow phosphorus tail gas as fuel, combustion is carried out in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot, causing the water in it to evaporate and concentrate. Specifically, this includes: By controlling the combustion conditions of the yellow phosphorus tail gas and the circulation flow rate of the organic heat carrier, the concentration temperature of the potassium formate solution is controlled at 200℃~250℃.

3. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Using yellow phosphorus tail gas as fuel, combustion is carried out in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot, causing the water in it to evaporate and concentrate. Specifically, this includes: The heating pot is provided with an insulation cover, which is fitted onto the outer wall of the heating pot and forms an isolation space between the heating pot and the heating pot.

4. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Start the cooling water circulation system and control the surface temperature of the rotating cooling drum to 20℃~50℃, allowing potassium formate liquid to cool and crystallize on the drum surface to form a crystalline layer. Specifically, this includes: The cooling water circulation system includes a chiller unit and a cooling circulation tower, which are used to maintain a constant cooling water temperature.

5. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Once the crystalline layer reaches a predetermined thickness, it is scraped off the surface of the drum by a scraper device to obtain solid potassium formate, which specifically includes: The scraper device includes a stainless steel scraper, the angle of which and its position close to the roller surface are adjustable.

6. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Using yellow phosphorus tail gas as fuel, combustion is carried out in an organic heat carrier boiler to heat the organic heat carrier. The heated high-temperature organic heat carrier, driven by a circulating pump, enters the coils inside the heating pot for closed-loop circulation, indirectly heating the potassium formate solution in the pot, causing the water in it to evaporate and concentrate. Specifically, this includes: The combustion device of the organic heat carrier boiler is configured to fully combust the yellow phosphorus tail gas, and the generated high-temperature flue gas exchanges heat with the organic heat carrier in the boiler through radiation and convection.

7. The process for preparing solid potassium formate by concentrating potassium formate solution using yellow phosphorus tail gas as a heat carrier as described in claim 1, characterized in that, Also includes: The obtained solid potassium formate product is in the form of flaky crystals with a purity of over 96%.

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