Real-time urea hydrolysis product gas composition prediction system

Abstract

The application discloses a urea hydrolysis product gas real-time component prediction system which is connected with a urea catalytic hydrolysis system of a coal-fired power plant and comprises a temperature sensing module, a pressure sensing module, a concentration sensing module, a core computing module and a product component output module.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of real-time component prediction of urea hydrolysis product gas, in particular to a real-time component prediction system of urea hydrolysis product gas. BACKGROUND

[0002] The selective catalytic reduction denitration technology is the mainstream flue gas denitration technology of coal-fired boilers at home and abroad, and its reaction mechanism is that the reducing agent ammonia (NH3) and NOx in the flue gas undergo oxidation-reduction reaction under the action of a suitable flue gas temperature range and a catalyst, and then generate non-polluting nitrogen and water. The preparation method of the SCR denitration reducing agent NH3 can be roughly divided into liquid ammonia method and urea decomposition method. The liquid ammonia method is mature, but according to the relevant requirements of the Hazardous Chemicals Major Hazard Source Identification Standard GB18218-2009, liquid ammonia storage tanks exceeding 10 tons are major hazard sources, which have a high safety risk. The urea decomposition method for ammonia preparation process includes pyrolysis and hydrolysis, and the urea hydrolysis method uses low-quality steam as a heating source in the running, which is superior to the urea pyrolysis technology in terms of equipment investment, operation and maintenance, and has stronger market competitiveness, and has been widely used in coal-fired power plants.

[0003] The urea hydrolysis system is complex, and the hydrolysis process is easily affected by many factors such as urea solution concentration, reactor temperature / pressure, etc. In the actual operation of the urea hydrolysis reactor, the hydrolysis process generally adopts a constant pressure or sliding pressure operation mode, and the temperature, pressure and other parameters will change, while the urea hydrolysis rate is very sensitive to the change of temperature and other parameters, so that the product gas component of the hydrolysis reactor changes greatly at this time. The product gas is extracted from the top outlet bypass of the hydrolysis reactor and enters the gas chromatograph, which can realize the analysis and measurement of the product gas component, but this measurement method is not suitable for the relatively harsh measurement conditions on site, and is not suitable for online continuous measurement. At present, the urea hydrolysis system lacks a real-time online monitoring system for the product gas component, which is not conducive to the accurate injection of ammonia. SUMMARY

[0004] The purpose of the present application is to provide a real-time component prediction system for urea hydrolysis product gas, which aims to solve the real-time component prediction of urea hydrolysis product gas.

[0005] The present application provides a real-time component prediction system for urea hydrolysis product gas, comprising:

[0006] Connected with the urea catalytic hydrolysis system of the coal-fired power plant, comprising,

[0007] A temperature sensing module, a pressure sensing module, a concentration sensing module, a core computing module and a product component output module;

[0008] The temperature sensing module is connected with the core computing module and is used to acquire the real-time temperature signal of the urea hydrolysis external reactor.

[0009] The pressure sensing module is connected with the core computing module, and is used for acquiring a real-time pressure signal of the urea hydrolysis external reactor;

[0010] The concentration sensing module is connected with the core computing module, and is used for acquiring real-time urea supply amount and dilution water amount signals of the urea hydrolysis external reactor;

[0011] The core computing module is connected with the product component output module, and is used for presetting a relationship graph set between a reactor temperature, a pressure and a urea solution concentration and a hydrolysis reaction product gas component, and establishing a function relationship between the reactor temperature, the pressure and the urea solution concentration and the reaction product gas;

[0012] The product component output module is used for searching the relationship graph set and the function relationship according to the real-time temperature signal, the real-time pressure signal and the real-time urea supply amount and dilution water amount signals to obtain a product gas component in a real-time running process of the urea catalytic hydrolysis system.

[0013] By adopting the embodiment of the present application, the real-time component prediction of the urea hydrolysis product gas can be realized.

[0014] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and in order to enable the above and other purposes, features and advantages of the present application to be more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the present application or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0016] Figure 1 is a schematic diagram of the real-time component prediction system of the urea hydrolysis product gas of the embodiment of the present application;

[0017] Figure 2 is a reactor temperature-hydrolysis reaction product gas yield relationship schematic diagram of the real-time component prediction system of the urea hydrolysis product gas of the embodiment of the present application;

[0018] Figure 3 is a urea solution concentration-hydrolysis reaction product gas yield schematic diagram of the real-time component prediction system of the urea hydrolysis product gas of the embodiment of the present application. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be described clearly and completely below in connection with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0020] Method embodiments

[0021] According to the embodiments of the present application, a urea hydrolysis product gas real-time component prediction system is provided, Figure 1 is a schematic diagram of the urea hydrolysis product gas real-time component prediction system of the embodiments of the present application, as Figure 1 shown, specifically comprising:

[0022] connected with the urea catalytic hydrolysis system of the coal-fired power plant, comprising,

[0023] a temperature sensing module, a pressure sensing module, a concentration sensing module, a core computing module and a product component output module;

[0024] The temperature sensing module is connected with the core computing module, and is used to acquire the real-time temperature signal of the urea hydrolysis external reactor.

[0025] The pressure sensing module is connected with the core computing module, and is used to acquire the real-time pressure signal of the urea hydrolysis external reactor.

[0026] The concentration sensing module is connected with the core computing module, and is used to acquire the real-time urea supply amount and dilution water amount signal of the urea hydrolysis external reactor.

[0027] The core computing module is connected with the product component output module, and is used to preset the relationship graph set between the reactor temperature, pressure and urea solution concentration and the hydrolysis reaction product gas component, and establish the functional relationship between the reactor temperature, pressure and urea solution concentration and the reaction gas product.

[0028] The product component output module is used to find the product gas component in the real-time running process of the urea catalytic hydrolysis system according to the real-time temperature signal, real-time pressure signal and real-time urea supply amount and dilution water amount signal.

[0029] The temperature range of the temperature module is 150-200℃.

[0030] The pressure range of the pressure sensor module is 0.5-1Mpa.

[0031] The concentration sensor module pressure range is 20%-80%.

[0032] The core computing module is specifically used for presetting a map set between reactor temperature, pressure and urea solution concentration and hydrolysis reaction product gas, fitting an exponential function for a function relationship between reactor temperature and hydrolysis reaction product gas yield, reflecting a function relationship between temperature and product gas yield under a constant pressure condition for the correlation between reactor pressure and hydrolysis reaction product gas yield, and fitting a first function polynomial for a function relationship between urea solution concentration and hydrolysis reaction product gas yield.

[0033] The urea hydrolysis product gas real-time component prediction system is connected with the coal-fired power plant urea catalytic hydrolysis system through a Modbus 485 communication protocol.

[0034] The object of the embodiment is a certain 660MW coal-fired unit SCR system, which has completed the liquid ammonia to urea project, adopts a urea catalytic hydrolysis ammonia production technical scheme with higher safety, economy and applicability, uses Holley PLC and DCS system, and after the transformation, the main newly added equipment includes a urea dissolving tank, a urea solution storage tank and a urea hydrolysis reactor, and the product gas at the outlet of the urea hydrolysis reactor is directly introduced into the downstream SCR reactor without arranging any product gas component measuring device, directly leading to great uncertainty of the ammonia supply quality of the urea hydrolysis system (only the total flow parameter of the product gas, without the real-time component parameter of meaningful NH3).

[0035] The urea hydrolysis product gas real-time component prediction system in the embodiment is installed in an externally hung dell server, data transmission between the sensing module and the urea hydrolysis system PLC is realized based on a Modbus 485 communication protocol, reactor temperature, reactor pressure, urea supply amount and dilution water amount signals are sequentially connected to a temperature sensing module, a pressure sensing module and a concentration sensing module, and a map set between reactor temperature, pressure and urea solution concentration and hydrolysis reaction product gas is preset in the core computing module, Figure 2 FIG. 1 is a reactor temperature-hydrolysis reaction product gas yield relationship diagram of the urea hydrolysis product gas real-time component prediction system of the embodiment of the present application; the relationship between "reactor temperature-hydrolysis reaction product gas yield" is fitted as an exponential function relationship y=e^(0.03656x), and the correlation between "reactor pressure-hydrolysis reaction product gas yield" is reflected through a function relationship between temperature and product gas yield under a constant pressure (0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa) condition, Figure 3 FIG. 2 is a urea solution concentration-hydrolysis reaction product gas yield diagram of the urea hydrolysis product gas real-time component prediction system of the embodiment of the present application; the relationship between "urea solution concentration-hydrolysis reaction product gas yield" is fitted through a first function polynomial y=-0.05+0.925x.

[0036] Based on the above urea hydrolysis product gas real-time component prediction system, according to the output results of the temperature sensing module, the pressure sensing module and the concentration sensing module, the corresponding lookup reactor temperature, pressure and urea solution concentration and hydrolysis reaction product gas between the atlas and the corresponding function relationship can be obtained, and then the product gas component in the real-time operation process of the urea catalytic hydrolysis system can be obtained, so as to effectively guide the subsequent precise ammonia injection.

[0037] The present application discloses a urea hydrolysis product gas real-time component prediction system, which is applied to a urea catalytic hydrolysis system of a coal-fired power plant.

[0038] The temperature sensing module, the pressure sensing module and the concentration sensing module are connected in sequence; the atlas of the reactor temperature, the pressure and the urea solution concentration and the hydrolysis reaction product gas is pre-stored in the core calculation module, and the matching urea hydrolysis product gas component is obtained by looking up the corresponding operating parameters.

[0039] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or equivalent replacements of the technical solutions of the embodiments of the present application do not make the essence of the corresponding technical solutions deviate from the scope of the present application.

[0040] ​

Claims

1. A urea hydrolysis product gas real-time component prediction system, characterized by, The urea catalytic hydrolysis system is connected with a coal-fired power plant urea catalytic hydrolysis system, comprising, The temperature sensing module, the pressure sensing module, the concentration sensing module, the core computing module and the product component output module; The temperature sensing module is connected with the core computing module, and is used for acquiring a real-time temperature signal of the urea hydrolysis external reactor; The pressure sensing module is connected with the core computing module, and is used for acquiring a real-time pressure signal of the urea hydrolysis external reactor; The concentration sensing module is connected with the core computing module, and is used for acquiring real-time urea supply amount and dilution water amount signals of the urea hydrolysis external reactor; The core computing module is connected with the product component output module, and is used for presetting a relationship graph set between reactor temperature, pressure and urea solution concentration and a hydrolysis reaction product gas, and establishing a function relationship between the reactor temperature, pressure and urea solution concentration and the reaction gas product; The product component output module is used for searching the relationship graph set and the function relationship according to the real-time temperature signal, the real-time pressure signal and the real-time urea supply amount and dilution water amount signals to obtain a product gas component in a real-time running process of the urea catalytic hydrolysis system. The core computing module is specifically used for presetting a graph set between reactor temperature, pressure and urea solution concentration and a hydrolysis reaction product gas, fitting a reactor temperature-hydrolysis reaction product gas yield function relationship into an exponential function relationship y = e^(0.03656x), reflecting a reactor pressure-hydrolysis reaction product gas yield correlation through a function relationship between temperature and product gas yield under a constant pressure condition, and fitting a urea solution concentration-hydrolysis reaction product gas yield function relationship into a first function polynomial y = -0.05 + 0.925x.

2. The system of claim 1, wherein, The temperature range of the temperature module is 150-200℃.

3. The system of claim 1, wherein, The pressure range of the pressure sensor module is 0.5-1Mpa.

4. The system of claim 1, wherein, The concentration sensor module pressure range is 20%-80%.

5. The system of claim 1, wherein, The urea hydrolysis product gas real-time component prediction system is connected with the coal-fired power plant urea catalytic hydrolysis system through a Modbus 485 communication protocol.

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