CN115470720A

CN115470720A - Simulation and optimization method for cement kiln co-processing organic solid waste process

Info

Publication number: CN115470720A
Application number: CN202211034859.5A
Authority: CN
Inventors: 杨家宽; 李星吾; 李叶青; 王加军; 梁莎; 虞文波; 王忠义; 黄亮; 肖可可; 胡敬平; 侯慧杰
Original assignee: Huazhong University of Science and Technology; Huaxin Cement Co Ltd
Current assignee: Huazhong University of Science and Technology; Huaxin Cement Co Ltd
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2022-12-13

Abstract

The invention belongs to the field of solid waste treatment and disposal, and discloses a simulation and optimization method of a cement kiln co-disposed organic solid waste process, which comprises the following steps: s1, selecting a physical property method and chemical components by using Aspen Plus software; s2, establishing a steady-state process simulation model; s3, inputting a model according to feeding parameters in the production process to obtain a calculation result; s4, comparing the calculation result with an actual measurement value in the production process, and if the requirement of receiving a limiting value is not met, adjusting the parameters of an operation unit in the steady-state process simulation model; and S5, inputting the feeding parameters corresponding to the improved process into the model to obtain a calculation result, and further judging whether the improved process is adjusted or not, so that process optimization is realized. The invention provides an effective tool for designing the co-processing process of the cement kiln for organic solid wastes, reducing the trial operation cost and improving the working efficiency by utilizing a steady-state flow simulation model of a specific subsystem and flow design.

Description

Simulation and optimization method for cement kiln co-processing organic solid waste process

Technical Field

The invention belongs to the field of solid waste treatment and disposal, and particularly relates to a simulation and optimization method for a cement kiln co-disposal organic solid waste process.

Background

The social activities and the industrial production can generate organic solid wastes such as household garbage, municipal sludge, traditional Chinese medicine dregs and the like. At present, the mainstream organic solid waste treatment method comprises landfill, incineration, composting and the like, wherein the incineration technology can quickly realize the harmlessness and reduction of the organic solid waste. Compared with single organic solid waste incineration equipment, the construction investment of the incineration equipment can be reduced by utilizing the conventional cement kiln to cooperatively treat the organic solid waste, and meanwhile, the organic solid waste incineration ash and cement raw materials are jointly fired into cement clinker, so that a hazardous waste treatment process is omitted, secondary pollution risk is avoided, and complete recycling of the organic solid waste can be realized.

Some cement enterprises have transformed the existing cement production line for disposing organic solid wastes in a synergic manner, but the different organic solid wastes have huge differences in properties such as moisture content, heat value and element composition, and most cement enterprises increase or decrease the adding amount of the organic solid wastes according to the quality of clinker and gas monitoring data, but the method has long time lag, high trial operation cost and long exploration period. Therefore, the method for simulating the actual production process of the cement kiln by using the software and researching the energy change and the material change in the cement kiln system is an effective method. Aspen Plus is a large-scale general flow simulation system applied to design of production devices in industrial processes, stable simulation and optimization of technological processes, is mostly applied to the fields of petrochemical industry and coal chemical industry, and has less application in the field of cement industry systems, particularly in the field of cooperative disposal of organic solid wastes by cement kilns.

In the 2010 Master academic paper of atmospheric pollution emission and energy utilization analysis in the process of cement pre-decomposition kiln based on Aspen _ Plus, caoguexue establishes a steady-state flow model for a suspension preheater, a decomposition kiln and a rotary kiln in a cement kiln system, does not consider a partial decomposition process of raw materials in the preheater, does not include a key technology bypass air release system for cement kiln cooperative disposal, and considers the whole cement clinker firing model as an adiabatic environment which is also not consistent with the actual production working condition. The model is mainly optimized for the traditional cement production process, the research on the cooperative disposal of organic solid wastes in the cement kiln is small, the sensitivity analysis module for analyzing alternative fuels only can analyze mixed fuels with fixed mixture ratio, after the mixture ratio is modified, the relevant parameters of the mixed fuels need to be manually calculated, and then the original coal stream is replaced, so that the flexible mixture ratio of any organic solid wastes cannot be realized. In 'research on cement kiln co-processing municipal solid waste system' of master thesis 2016, the point of dongqi uses Aspen Plus to establish a flow model for disposing domestic waste by a waste incinerator and a cement rotary kiln, but the process is essentially implemented by separately burning waste and burning cement, and the problems of unreasonable hypothesis, only single organic solid waste domestic waste consideration, and the like exist. In the 2018 master paper simulation and analysis of acid-making and cement-making from phosphogypsum based on Aspen _ Plus, only phosphogypsum is studied as a part of raw materials in a model established by xiano, and the relevant process of co-processing organic solid waste by a cement kiln is not involved. In journal paper "simulation and emission reduction optimization research based on Aspen Plus cement kiln NOx generation", liudingping et al only carries out modeling on a precalciner and a rotary kiln in the traditional cement production process, carries out research on the NOx emission process, and does not relate to research related to the cooperative disposal of organic solid waste by a cement kiln. The invention relates to a Chinese patent (publication No. CN 103400196B) and discloses a modeling optimization method for clean production in a cement clinker firing process, wherein a chemical reaction kinetics is used for describing fuel combustion and raw material decomposition processes in a built model, but the combustion process and the complexity are high, the calculation amount is greatly increased by carrying out chemical reaction kinetics calculation on each type of combustion products, meanwhile, the model separately calculates the combustion process and the gas-solid heat exchange process, the influence of the environment temperature on the form of the combustion products is neglected, a process module for cooperatively disposing organic solid wastes (domestic wastes) by a cement kiln is added in the model, but the mixing of various organic solid wastes needs to manually calculate the property and the energy of a mixture firstly, then the mixed fuel stream replaces the original fuel stream, the manual calculation needs to be carried out again when the mixing proportion is replaced every time, and the research on cooperatively disposing the organic solid wastes by the cement kiln is not facilitated.

In conclusion, currently, simulation research on synergistic treatment of organic solid wastes by using Aspen Plus for cement kilns is less, and the problems that partial assumption is unreasonable, environmental heat exchange is neglected, related process modules are lacked and the like still exist in the existing model. Meanwhile, the existing model aims at single organic solid wastes which are mostly fixed in research objects, the organic solid wastes can be mixed only according to a fixed proportion, and input parameters such as element composition, heat value and the like of the mixed organic solid wastes are calculated manually, so that the operation is complicated. In actual production, the organic solid wastes cooperatively treated by the cement kiln have great difference in physicochemical properties such as type, quality, water content, element proportion, heat value and the like, the mixed combustion proportion of different types of organic solid wastes in the cement kiln can be dynamically adjusted at any time according to production requirements, and the influence of the change of the properties of the organic solid wastes on the temperature change of the cement kiln or the core process such as a flue gas emission rule and the like cannot be explored by the existing model. Therefore, a model for the cooperative disposal of organic solid waste in the cement kiln is still needed, and the simulation calculation analysis can be accurately and conveniently performed on the aspects of temperature change, flue gas emission, mass balance, energy balance and the like of a core process unit, such as a decomposing furnace, in the cooperative disposal of organic solid waste in the cement kiln system, so as to provide theoretical data for the optimization of the cooperative disposal process of the cement kiln.

Disclosure of Invention

Aiming at the defects or the improvement requirements in the prior art, the invention aims to provide a simulation and optimization method for a cement kiln co-disposal organic solid waste process, wherein an Aspen Plus software is utilized to establish a steady-state flow simulation model, 4 subsystems, namely a suspension preheater subsystem, a decomposition furnace subsystem, a rotary kiln subsystem and an organic solid waste decomposition subsystem, are arranged in the simulation model, and a material stream and a heat stream are matched to perform simulation calculation analysis on the aspects of temperature change, smoke emission, mass balance, energy balance and the like of a core process unit, such as a decomposition furnace, in the cement kiln system co-disposal organic solid waste process; the actual requirements of the improved process are combined, the improved process can be effectively predicted, and further, a basis is provided for judging whether the improved process meets expectations or needs to be adjusted, and process optimization is achieved. The method provided by the invention provides an effective tool for the design of the cement kiln co-treatment process of organic solid wastes, reduces the trial operation cost and improves the working efficiency.

In order to achieve the purpose, the invention provides a simulation and optimization method of a cement kiln co-processing organic solid waste process, which is characterized by comprising the following steps of:

(S1) selecting a physical property method used by software calculation by utilizing Aspen Plus software, simultaneously selecting a conventional component and a solid phase component involved in the software calculation, taking other components selected in advance as unconventional components, and newly building software to calculate the unconventional components involved;

(S2) establishing a steady-state process simulation model, wherein the steady-state process simulation model comprises a plurality of subsystems, and each subsystem comprises a stream and a plurality of operation units; all the subsystems are connected with each other through streams; these subsystems include:

a suspension preheater subsystem: the system is used for corresponding suspension preheater equipment in cement production, wherein streams are arranged according to gas and solid flow directions in the cement production process;

decomposition furnace system: the decomposing furnace equipment used in cement production comprises a raw material decomposition corresponding operation unit and a combustion reaction corresponding operation unit; the stream in the decomposing furnace system is arranged according to the operation unit corresponding to raw material decomposition in the decomposing furnace system and the operation unit corresponding to combustion reaction in the decomposing furnace system; wherein the operation unit corresponding to the combustion reaction is a Gibbs reactor (RGibbs) operation unit;

a rotary kiln subsystem: the rotary kiln equipment used in cement production comprises a raw material decomposition corresponding operation unit and a combustion reaction corresponding operation unit; the stream in the rotary kiln subsystem is arranged according to the operation unit corresponding to the decomposition of the raw material in the rotary kiln subsystem and the operation unit corresponding to the combustion reaction in the rotary kiln subsystem; wherein the operation unit corresponding to the combustion reaction is a Gibbs reactor operation unit;

the organic solid waste decomposition subsystem: the device is used for the decomposition process of the corresponding organic solid wastes in decomposing furnace equipment and rotary kiln equipment in cement production, wherein streams are arranged according to a physicochemical reaction process of drying and pyrolysis in sequence;

the steady-state process simulation model also comprises: calculator module, design specification module and sensitivity analysis module, wherein:

the calculator module: a calculation process for controlling each operation unit;

the design specification module: the device is used for controlling a variable in the steady-state process simulation model to be a specified value or a specified range;

the sensitivity analysis module: the design specification module is used for matching with the design specification module to change a certain variable in a specified range according to a preset step length;

(S3) inputting the feeding parameters into corresponding streams in the steady-state flow simulation model obtained in the step (S2) for simulation according to the feeding parameters in the production process, and obtaining the calculation results of each subsystem through calculation of the model;

the feeding parameters simultaneously comprise the type of the feeding stream and the parameters of the feeding stream; wherein the feed stream species comprise: different raw materials, different fuels and air are added into the cement kiln; the feed stream parameters included: mass flow, temperature and chemical composition;

the calculation result simultaneously comprises: temperature, flow rate and composition;

(S4) comparing the calculation result obtained in the step (S3) with an actual measurement value in the production process, if the relative error exceeds a preselected acceptable limit value, modifying the parameters of the operation unit in the steady-state process simulation model in the step (S2), and repeating the step (S3) and the step (S4) until the relative error does not exceed the preselected acceptable limit value;

(S5) inputting the feeding parameters corresponding to the improved process into a steady-state process simulation model based on the preselected improved process, and obtaining the calculation results of each subsystem through the calculation of the model; and judging whether to adjust the improved process or not based on the calculation result so as to realize process optimization.

As a further preferred aspect of the present invention, the step (S5) specifically includes the following substeps:

(S5-1) establishing an interactive interface, and enabling the stream in the steady-state process simulation model and the sensitivity analysis module to be respectively linked with the interactive interface;

(S5-2) inputting the feeding parameters corresponding to the improved process into a steady-state process simulation model through the interactive interface for simulation based on the preselected improved process, and obtaining the calculation results of each subsystem through the calculation of the model; and judging whether to adjust the improved process or not based on the calculation result so as to realize process optimization.

As a further preferred aspect of the present invention, in the step (S2), the suspension preheater subsystem is divided into five stages, i.e., C1 to C5, from top to bottom, and four processes of gas-solid mixing heat exchange, carbonate decomposition, surface heat dissipation and gas-solid separation, which occur in a suspension preheater device in cement production, are respectively implemented by a Mixer (Mixer) operation unit, a stoichiometric reactor (RStoic) operation unit, a heat exchanger (Heater) operation unit and an SSplit operation unit; the C1 stage comprises a mixer operation unit, a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams; each C2-C4 stage comprises a mixer operation unit, a chemical meter reactor operation unit, a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams; the C5 stage comprises a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams;

and, for any one stoichiometric reactor (RStoic) operation unit, they are all used for defining the decomposition reaction of calcium carbonate and magnesium carbonate, the decomposition rate is preset to be 1.5% -3%;

for any one heat exchanger (Heater) operation unit, their thermal loads are preset to-1.0X 10 ⁷ to-3.0X 10 ⁶ kJ/h；

The SSplit operation units are used for splitting, each SSplit operation unit comprises 2 outlets, wherein a stream split from the outlet positioned above the operation unit is recorded as an upper stream, and a stream split from the outlet positioned below the operation unit is recorded as a lower stream; for any SSplit unit, their gas flow direction is preset as: 93% -95% enter the upper stream, and the solid flow directions of the upper stream and the upper stream are preset as follows: 87% -96% of the liquid enters a lower material flow stream; wherein the upper stream of the SSplit process units in the C1 stage does not connect to any process unit, the upper stream of the SSplit process units in the C2-C5 stage enters the mixer process unit of the upper stage suspension preheater; the lower stream of the SSplit operation unit in the C1-C3 stage enters a mixer operation unit of a next stage suspension preheater, the lower stream of the SSplit operation unit in the C4 stage enters a Gibbs reactor operation unit in the decomposing furnace system, and the lower stream of the SSplit operation unit in the C5 stage enters a Gibbs reactor operation unit in the rotary kiln subsystem;

all feed streams in the suspension preheater subsystem are connected to the mixer operating unit in the C1 stage, the feed streams simultaneously comprising a cement raw stock stream, a raw meal carrying air stream; the outlet stream in the suspension preheater subsystem comprises both an upper stream from the SSplit process unit in the C1 stage and a lower stream from the SSplit process unit in the C5 stage.

As a further preferred of the present invention, in the step (S2), the decomposing furnace system is used for simulating pulverized coal decomposition, combustion reaction, carbonate decomposition and surface heat dissipation processes, which are respectively realized by heat flow strands connected with a yield reactor (RYield) operating unit, a gibbs reactor (RGibbs) operating unit, a stoichiometric reactor operating unit and a stoichiometric reactor operating unit; wherein the yield reactor operating unit, the Gibbs reactor operating unit and the stoichiometric reactor operating unit are connected in sequence;

a yield reactor operating unit controlled by the calculator module;

a stoichiometric reactor operation unit used for defining the decomposition reaction of calcium carbonate and magnesium carbonate, wherein the decomposition rate is preset to be 80-82%;

the thermal load in the hot stream was preset at-2.5X 10 ⁷ to-1.3X 10 ⁷ kJ/h；

A feed stream in the decomposition furnace system is connected to a yield reactor operation unit, the feed stream being a material stream of decomposition furnace coal; an outlet stream in the decomposition furnace system, which is an outlet stream of the stoichiometric reactor operating unit, is connected to the heat exchanger operating unit of the C5 stage in the suspension preheater subsystem.

As a further preferable aspect of the present invention, in the step (S2), the rotary kiln subsystem is configured to simulate processes of coal powder decomposition, combustion reaction, carbonate decomposition, surface heat dissipation, gas-solid separation, and bypass ventilation, and includes a yield reactor operation unit, a mixer operation unit, a gibbs reactor operation unit, a stoichiometric reactor operation unit, a heat exchanger operation unit, an SSplit operation unit, and an FSplit operation unit, which are sequentially connected; wherein, the processes of simulating coal powder decomposition, combustion reaction, carbonate decomposition and surface heat dissipation are respectively realized by using a productive reactor operation unit, a Gibbs reactor operation unit, a stoichiometric reactor operation unit and a heat exchanger operation unit; the simulation of the gas-solid separation and the bypass ventilation process are realized by using an SSplit operation unit and an FSplit operation unit respectively;

wherein the yield reactor operating unit is controlled by the calculator module;

a stoichiometric reactor operation unit for defining a decomposition reaction of calcium carbonate and magnesium carbonate, the decomposition rate being set to 100% in advance;

the heat load of the heat exchanger operation unit was previously set to-7.0X 10 ⁷ to-5.0X 10 ⁷ kJ/h；

The gas-solid separation efficiency in the SSplit operation unit is preset to 100%;

separating a flow in the FSplit operation unit to simulate the wind lost by a bypass air bleeding system, and marking the flow as a bypass air bleeding flow, wherein the separation ratio of the bypass air bleeding flow is preset to be 3% -5%;

the number of feed streams in the rotary kiln subsystem is 4, and the feed streams specifically comprise rotary kiln coal, kiln inlet clean air, primary air and secondary air; wherein the rotary kiln coal stream is connected to a productivity reactor operating module; the three streams of kiln-entering clean air, primary air and secondary air are combined into a single stream by the mixer operation unit, and the single stream is then connected to the Gibbs reactor operation module; the number of outlet streams is 3, and the outlet streams are respectively as follows: the lower material stream in the SSplit operation unit is used as a cement clinker outlet stream and is not connected with any operation unit; the bypass air bleeding stream in the FSplit operation unit is not connected with any operation unit; the other streams except the bypass vent stream in the FSplit operating unit are connected to the mixer operating unit in the organic solid waste decomposition subsystem.

As a further preferred aspect of the present invention, in the step (S2), the organic solid waste decomposition subsystem includes a mixer operation unit, a stoichiometric reactor operation unit, a Sep operation unit, a yield reactor operation unit, a mixer operation unit, and an FSplit operation unit, which are connected in sequence; the organic solid waste decomposition subsystem is used for simulating the drying and decomposition processes of the organic solid waste and is respectively realized by a stoichiometric reactor operation unit and a yield reactor operation unit; wherein, the first and the second end of the pipe are connected with each other,

the stoichiometric reactor operating unit and the yield reactor operating unit are controlled by the calculator module;

after passing through a stoichiometric reactor operation unit, an organic solid waste stream is divided by using a Sep operation unit, so that each type of organic solid waste is independently decomposed in a yield reactor operation unit, decomposition products and heat required by decomposition are respectively combined into a material stream and a hot stream by a mixer unit, 2 streams are respectively divided by using an FSplit operation unit, the division ratio is preset to be 95;

in the organic solid waste decomposition subsystem, the number of operation units of the yield reactor is 5-15, and the number of operation units of the FSplit reactor is 2;

the total number of the feeding streams in the organic solid waste decomposition subsystem is 4, and the feeding streams specifically comprise organic solid waste, primary air, A-row tertiary air and B-row tertiary air; wherein the organic solid waste stream is connected to a stoichiometric reactor operating unit; the primary air, the tertiary air in the row A and the tertiary air in the row B are mixed by the mixer operation unit and then are connected to the productivity reactor operation unit; the number of outlet streams is 4, and the outlet streams specifically comprise 2 material flow streams and 2 heat flow streams which are divided by 2 FSplit operation units, wherein 1 material flow stream with the division ratio of 95% and 1 heat flow stream with the division ratio of 95% enter a Gibbs reactor operation unit in a decomposition furnace system, and 1 material flow stream with the division ratio of 5% and 1 heat flow stream with the division ratio of 5% enter the Gibbs reactor operation unit in a rotary kiln subsystem.

More preferably, in the step (S1), the physical property method is a PR-BM method;

the chemical components are pre-classified into three categories, namely: conventional components, solid phase components, and unconventional components; the conventional component and the solid-phase component are obtained by selecting from a software database, and the non-conventional component is obtained by newly building;

the conventional component comprises H ₂ O、N ₂ 、O ₂ 、NO ₂ 、NO、S、SO ₂ 、SO ₃ 、H ₂ 、Cl ₂ HCl, CO and CO ₂ ；

The solid phase component comprises C and CaCO ₃ 、CaO、MgCO ₃ MgO and CaSO ₄ ；

The non-conventional components comprise various organic solid wastes, coal and incombustible ash in the organic solid wastes and the coal, and also comprise inert components which are used for representing that the cement raw meal comprises SiO ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And (c) internal components other than carbonates.

As a further preferred embodiment of the present invention, in the step (S5-1), the interactive interface is implemented by Excel software, MATLAB software, software written in Python language, or software capable of implementing ActiveX technology connection;

preferably, the interactive interface comprises at least two interfaces, wherein one interface is used for inputting the value or the variation range of the feeding parameter, and the other interface is used for inputting the properties of the coal and the organic solid wastes; the properties of the coal and organic solid waste simultaneously comprise industrial analysis data, elemental analysis data, dry basis low calorific value: wherein the industrial analysis data simultaneously comprises the content of application-based moisture, the content of dry-based ash, the content of dry-based volatile components and the content of dry-based fixed carbon; the element analysis data simultaneously comprises C content, H content, O content, N content, S content and Cl content;

more preferably, when the feeding parameter in the step (S5-2) is a fixed value, the fixed value is inputted into a corresponding stream of a steady-state process simulation model through the interactive interface; and (5) when the feeding parameter in the step (S5-2) is an interval range, inputting the feeding parameter into a sensitivity analysis module of the steady-state process simulation model through the interactive interface.

In a further preferred embodiment of the present invention, in the step (S5), it is determined whether to adjust the improvement process based on the calculation result, specifically, it is determined whether to adjust the improvement process based on a calculation result of the temperature of the cement kiln equipment, a calculation result of the volume of discharged flue gas, a calculation result of the concentration of flue gas components, a calculation result of coal consumption, or a calculation result of the proportion of co-combustion of organic solid wastes.

As a further preferred aspect of the present invention, in the step (S4), an absolute value of the preselected acceptance limit value is preselected to be 4% to 6%.

Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) According to the simulation and optimization method, a steady-state flow simulation model is established by utilizing Aspen Plus software, 4 subsystems of a suspension preheater subsystem, a decomposition furnace subsystem, a rotary kiln subsystem and an organic solid waste decomposition subsystem are arranged in the simulation model, and a material stream and a heat stream are matched, so that simulation calculation analysis can be performed on the aspects of temperature change, smoke emission, mass balance, energy balance and the like of a core process unit, such as a decomposition furnace, in the process of cooperatively disposing organic solid waste by a cement kiln system.

(2) The establishment of the steady-state flow simulation model and the parameter selection of the operation unit are suitable for the cement kiln co-processing organic solid waste process adopted by most cement enterprises in China. The invention can particularly independently set the organic solid waste decomposition and bypass air-release related subsystems, can preferably abandon the assumption of adiabatic conditions in the aspect of heat calculation, considers the heat loss caused by equipment heat dissipation, and has higher reliability.

(3) The invention preferably selects a specific operation unit, for example, a stoichiometric reactor unit is used for simulating the decomposition process of the cement raw meal, a Gibbs reactor unit is used for simulating the combustion reaction process, the model calculation amount is reduced under the condition of ensuring the simulation accuracy, meanwhile, the arrangement sequence of the operation units is reasonably adjusted, the decomposition process of the cement raw meal is arranged before the combustion reaction, and the temperature calculation in the Gibbs reactor unit corresponding to the combustion reaction is closer to the actual production.

(4) According to the invention, each type of organic solid waste is preferably independently calculated in the drying and decomposition processes, the type, quality, proportion, property and the like of the organic solid waste are added or changed without manually calculating the parameters of the mixture, and the model can automatically calculate and input the related parameters of the mixture.

(5) The model is established aiming at the cement kiln co-processing organic solid waste process, the influence of the change of single or multiple organic solid waste types, feeding amount, physicochemical properties and the like on the cement kiln temperature, smoke emission, coal consumption or other production indexes in the cement kiln co-processing organic solid waste process can be predicted by a quantitative method, and auxiliary data are provided for the cement enterprises to carry out the co-processing process optimization.

(6) In addition, the interactive interface can be preferably set to operate and call the model, and except for debugging personnel, the operating personnel does not need to know the modeling method or the operating principle of the Aspen Plus, so that the learning cost is reduced, and the universality of the method is improved.

(7) The method carries out full-flow simulation on the cement burning system, and breaks through the limitation that only the local process of the cement burning system is simulated in mainstream cement process simulation research; in addition, the modeling simulation is carried out on the cement kiln co-processing process by using chemical simulation software, so that the problems of large computational load and long time consumption of applied computational fluid mechanics in mainstream cement process simulation research are solved; the invention aims to predict the influence of the change of production raw materials on the production process and production parameters after the cement plant is built and operated, and is also different from the size scale design of cement production equipment in mainstream cement process simulation research.

Drawings

FIG. 1 is a gas-solid flow diagram of a cement kiln co-processing process.

FIG. 2 is a steady-state flow simulation model of cement kiln co-processing organic solid waste, which is established by using Aspen Plus software in the invention.

FIG. 3 is an illustration of the operational elements used in the steady-state flow simulation model of FIG. 2.

Fig. 4 is a diagram showing the output result of the model in embodiment 1 of the present invention.

FIG. 5 is a graph showing the effect of the water content of the sludge on the concentration of pollutants in the flue gas in example 2 of the present inventionA graph of the output results (corresponding to a fixed sludge feed rate of 20t/h, see example 2 below for details); wherein (a) in FIG. 5 corresponds to SO ₂ Concentrations, FIG. 5 (b) for CO concentration, FIG. 5 (c) for NO concentration, and FIG. 5 (d) for CO concentration ₂ And (4) concentration.

FIG. 6 is a graph showing the output results of the influence of the sludge feeding amount and the water content on the temperature in example 3 of the present invention; wherein (a) in fig. 6 corresponds to the outlet flue gas temperature, and (b) in fig. 6 corresponds to the decomposing furnace temperature.

Fig. 7 is a schematic flowchart corresponding to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The simulation and optimization method of the cement kiln co-processing organic solid waste process can comprise the following steps: (1) Opening Aspen Plus software, selecting a physical property method from a physical property library, and selecting or establishing a chemical component; (2) Selecting and adding an operation unit and a stream composition subsystem from a model library of software, adding modules to the subsystems and connecting the subsystems to form a steady-state flow simulation model; (3) Inputting the feeding parameters of the cement kiln in the production process into a steady-state flow simulation model for calculation to obtain the calculation data of temperature, flow, components and the like in each subsystem; (4) Comparing the calculated data with the production data of the corresponding production link, if the relative error exceeds the acceptance limit value, modifying the parameters of the operation unit in the steady-state process simulation model, and repeating the steps (3) to (4) until the relative error is within the acceptance limit value (relative error = (| simulated value-actual value |)/actual value); (5) Establishing an interactive interface, and establishing a link between the model feeding parameters and the interactive interface; (6) Determining an expected improved process, and inputting the feeding parameters of the cement kiln in the improved process into a steady-state process simulation model; (7) And (4) performing operation simulation, calculating through a steady-state flow simulation model to obtain calculation data of temperature, flow, components and the like in each subsystem, analyzing the calculation data, adjusting an expected improved process, and completing a process optimization process.

Specifically, the method comprises the following steps:

(1) Opening Aspen Plus software, selecting a physical property method for software calculation in a physical property menu, and selecting or establishing a chemical component related to the software calculation;

(2) Selecting and adding an operation unit and a stream from a model library of software in a simulation menu, connecting the operation unit and the stream to form different subsystems, connecting the subsystems with each other through the stream to form a combined system, adding a calculator, a design specification and a sensitivity analysis module in the combined system, and finally forming a steady-state flow simulation model;

(3) Inputting feeding parameters of raw materials, fuel and air mass flow, temperature, chemical components and the like added into the cement kiln in the production process into corresponding streams in the subsystems in the step 2, and performing operation simulation, and calculating through the steady-state flow simulation model in the step 2 to obtain calculation data of the temperature, the flow, the components and the like in each subsystem;

(4) Comparing the calculated data obtained in the step 3 with the production data of the corresponding production link, if the relative error exceeds an acceptance limit value, modifying the parameters of the operation unit in the step 2, and repeating the step 3 and the step 4 until the relative error is within the acceptance limit value;

(5) Establishing an interactive interface in Office software, MATLAB software, software compiled by Python language or software capable of realizing ActiveX technical connection, and establishing a link between the stream and sensitivity analysis module in the step 2 and the interactive interface;

(6) Determining an expected improved process, inputting feeding parameters of raw materials, fuel and air to be added by the cement kiln, such as mass flow, temperature and chemical components in the improved process into a corresponding stream or sensitivity analysis module in the subsystem in the step 2 by using the interactive interface in the step 5;

(7) And (3) performing operation simulation, calculating by the steady-state flow simulation model in the step (2), obtaining calculation data of temperature, flow, components and the like in each subsystem, analyzing the calculation data, adjusting an expected improved process, and completing a process optimization process.

Wherein, the physical property method in the step 1 can be PR-BM method.

Wherein, the chemical components in the step 1 can comprise: conventional components, solid phase components and unconventional components are selected from a database carried by software, and the unconventional components need to be newly built by a user. Selected conventional components have H ₂ O、N ₂ 、O ₂ 、NO ₂ 、NO、S、SO ₂ 、SO ₃ 、H ₂ 、Cl ₂ 、HCl、CO、CO ₂ (ii) a The selected solid phase component is C, caCO ₃ 、CaO、MgCO ₃ 、MgO、CaSO ₄ (ii) a The invention divides the cement raw material into CaCO ₃ 、MgCO ₃ And an inert component replacing SiO ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates. The newly-built unconventional components comprise: incombustible ash in various organic solid wastes, coal and the both and inert components in cement raw materials.

The subsystems in step 2 may include four subsystems of a suspension preheater, a decomposing furnace, a rotary kiln and organic solid waste decomposition, and may respectively correspond to three devices of the suspension preheater, the decomposing furnace and the rotary kiln in cement production and a decomposition process of organic solid waste in the decomposing furnace or the rotary kiln.

The suspension preheater subsystem can be divided into five stages from top to bottom, four processes of gas-solid mixing heat exchange, carbonate decomposition, surface heat dissipation and gas-solid separation in the preheater can be respectively realized by a Mixer (Mixer), a stoichiometric reactor (RStoic), a heat exchanger (Heater) and an SSplit unit, and each stage of preheater can comprise part or all four operation units. The decomposition reaction of calcium carbonate and magnesium carbonate is defined in the stoichiometric reactor unit, and the decomposition rate can be set to 1.5% -3%. The heat load in the heat exchanger can be set to-1.0X 10 ⁷ to-3.0X 10 ⁶ kJ/h. In SSplit cells, gas flows toCan be as follows: 93-95% of the waste water enters a primary preheater; the solids flow direction may be: 87% -96% of the feed gas enters the next-stage preheater.

The decomposing furnace system simulates the processes of coal powder decomposition, combustion reaction, carbonate decomposition and surface heat dissipation and can be respectively realized by a yield reactor unit (Ryield), a Gibbs reactor (RGibbs), a stoichiometric reactor unit and a heat flow strand connected with the stoichiometric reactor unit. Wherein the yield reactor unit is controlled by the calculator module in the step 2, the stoichiometric reactor unit defines the decomposition reaction of two carbonates of calcium carbonate and magnesium carbonate, the decomposition rate can be set to be 80-82%, and the heat load in the heat flow strand can be-2.5 x 10 ⁷ to-1.3X 10 ⁷ kJ/h。

The rotary kiln subsystem simulates the processes of coal powder decomposition, combustion reaction, carbonate decomposition, surface heat dissipation, gas-solid separation and bypass air release, and the first four processes can be realized by using a yield reactor unit, a Gibbs reactor, a stoichiometric reactor and a heat exchanger unit respectively. The gas-solid separation and the bypass air release process can be realized by an SSplit unit and an FSplit unit respectively. Wherein the yield reactor unit is controlled by the calculator module in step 2, the stoichiometric reactor unit defines the decomposition reaction of two carbonates of calcium carbonate and magnesium carbonate, the decomposition rate of the carbonate can be set to 100%, and the heat load in the heat exchanger unit can be set to-7.0 × 10 ⁷ to-5.0X 10 ⁷ kJ/h, the gas-solid separation efficiency in the SSplit unit can be set to 100%, the separation of one stream in the FSplit unit simulates the wind lost by a bypass air bleed system, and the stream separation ratio can be set to 3% -5%.

The organic solid waste decomposition subsystem simulates the drying and decomposition processes of the organic solid waste and is respectively realized by a stoichiometric reactor and a yield reactor. The stoichiometric reactor and the yield reactor unit are controlled by the calculator module in the step 2, the organic solid waste stream is dried and then is divided by using a Sep module, so that each type of organic solid waste is independently decomposed in the yield reactor unit, all organic solid waste component decomposition products and heat required by decomposition are combined by a mixer unit and then are divided by using an FSplit unit, 95% of the organic solid waste component decomposition products can be preset to enter a Gibbs reactor operation unit in a decomposition furnace system, and the rest 5% of the organic solid waste component decomposition products enter the Gibbs reactor operation unit in a rotary kiln subsystem. The number of production reactor operating units in this subsystem may be 5-15.

Wherein, the streams in each subsystem in the step 2 can be set according to different principles: the suspension preheater subsystem is arranged according to the flow direction of gas and solid in the cement production process, as shown in figure 1; the decomposing furnace system and the rotary kiln subsystem modify part of the process sequence on the basis of the actual production process, and the stream firstly passes through a corresponding operation unit for raw material decomposition and then passes through a corresponding operation unit for combustion reaction; the organic solid waste decomposition subsystem is arranged according to the physicochemical reaction process of drying and pyrolysis.

The calculator module in the step 2 is used for controlling the operation unit in the step 2, the design specification module in the step 2 is used for controlling a variable in the steady-state process simulation model in the step 2 to be a specified value or a specified range, and the sensitivity analysis module in the step 2 can be combined with the design specification module to adjust the feeding parameters in the step 3 to change in a specified step length within a specified range. The steady-state flow simulation model described in step 2 may use a "transmission" module or the like of the Aspen Plus software for auxiliary calculation, but is not required.

The steady-state process simulation model in step 2 is shown in fig. 2 after being combined.

Wherein, the acceptance limit value in the step 4 can be 4-6%.

Wherein, the interactive interface in the step 5 can be set to at least comprise two interfaces, one interface is used for inputting the feeding temperature, the flow value or the variation range, and the other interface is used for inputting the properties of the coal and the organic solid waste raw materials, such as industrial analysis data, elemental analysis data, dry-based lower heating value and the like.

If the feeding parameters in the step 6 are constant values, inputting the constant values into the corresponding streams of the steady-state process simulation model in the step 2 through the interactive interface in the step 5; and if the feeding parameters in the step 6 are range values, inputting the range values into a sensitivity analysis module in the steady-state process simulation model in the step 2 through the interactive interface in the step 5.

Wherein, the calculation data in step 7 can be the temperature of the cement kiln equipment, the volume of discharged flue gas, the concentration of flue gas components, the coal consumption or other production indexes.

The following are specific examples:

example 1:

the purpose of this example is to investigate the effect of the change of the feeding amount of a Refuse Derived Fuel (RDF) with known properties on the coal consumption and tertiary air flow of a decomposing furnace within the range of 80-100t/h when the temperature of the decomposing furnace is kept at 890 ℃. The purpose is realized by the following technical scheme:

a simulation and optimization method for co-processing organic solid waste by a cement kiln based on Aspen Plus comprises the following steps:

(1) The Aspen Plus software is opened, the PR-BM method is selected as the physical property method for calculating the software in the physical property menu, the software database is provided with the conventional components and the solid phase components, and other components which are not contained in the conventional component library and the solid phase component library can be newly established through the entrance of the unconventional components in the software, and the specific properties of the components can be automatically input. Conventional, solid phase components were selected and added from the software database. The conventional component selected is H ₂ O、N ₂ 、O ₂ 、NO ₂ 、NO、S、SO ₂ 、SO ₃ 、H ₂ 、Cl ₂ 、HCl、CO、CO ₂ (ii) a The selected solid phase component is C, caCO ₃ 、CaO、MgCO ₃ 、MgO、CaSO ₄ (ii) a The new component is composed of RDF, coal and incombustible ash in both, and the inert component in cement raw material is substituted for SiO in cement raw material ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates.

(2) Selecting and adding an operation unit and a stream from a model library of Aspen Plus software, connecting the operation unit and the stream to form 4 subsystems of a suspension preheater, a decomposing furnace, a rotary kiln and organic solid waste decomposition, wherein the operation unit in each subsystem is arranged as follows:

in the suspension preheater subsystem, the suspension preheater subsystem is divided into five stages from top to bottom, wherein the stage C1 comprises 3 processes of gas-solid mixing heat exchange, surface heat dissipation and gas-solid separation, and the stage C5 comprises 2 processes of surface heat dissipation and gas-solid separation. Each stage of C2-C4 comprises 4 processes of gas-solid mixing heat exchange, carbonate decomposition, surface heat dissipation and gas-solid separation.

4 processes of gas-solid mixing heat exchange, carbonate decomposition, surface heat dissipation and gas-solid separation are respectively realized by a mixer, a stoichiometric reactor, a heat exchanger and an SSplit unit. In a stoichiometric reactor unit CaCO is defined ₃ And MgCO ₃ The decomposition rates in the stoichiometric reactor units of C2-C4 are 1.5%, 2.0% and 2.5%, respectively. The heat loads in the C1-C5 stage heat exchangers are-6841783, -4719676, -6206905, -7391566, -8451027kJ/h respectively. In the C1-C5 stage SSplit unit, the gas flows to: 95 percent of the mixture enters the upper stage, and the rest enters the lower stage; the solid flow direction is as follows: the C1-C5 stages respectively enter the next stage by 96 percent, 90 percent, 87 percent and 90 percent, and the rest enter the previous stage.

The decomposing furnace system simulates the processes of coal powder decomposition, coal powder combustion, carbonate decomposition and surface heat dissipation, and a calculator module written by Fortran is used for controlling a yield reactor unit to decompose coal into C and H according to element composition ₂ 、N ₂ 、Cl ₂ 、S、O ₂ 、H ₂ O and inert ASH ASH, the decomposition products of coal and the heat required for decomposition are mixed with other streams in a Gibbs reactor unit and then subjected to a combustion reaction, the carbonate decomposition is realized by a stoichiometric reactor unit, in which CaCO is defined ₃ And MgCO ₃ The reaction rate of the decomposition reaction is 80%, the chemical metering reactor is connected with a heat flow strand, and the heat load of the heat flow strand is-17879312 kJ/h.

The rotary kiln subsystem simulates the processes of coal powder decomposition, coal powder combustion, carbonate decomposition, surface heat dissipation, gas-solid separation and bypass air discharge, and uses a calculator module written by Fortran to control a yield reactor unit to decompose coal into C and H according to element composition ₂ 、N ₂ 、Cl ₂ 、S、O ₂ 、H ₂ O and inert Ash ASH, decomposition products of coal and heat required for decomposition are mixed with other streams in a Gibbs reactor unit to generate combustion reaction, carbonate decomposition is realized by a stoichiometric reactor unit, and CaCO is defined in the stoichiometric reactor unit ₃ And MgCO ₃ The reaction rate was 100% in all cases. The heat load of the heat exchanger unit is-60941283 kJ/h, and the gas-solid separation and the bypass air release process are respectively realized by the SSplit unit and the FSplit unit. The gas-solid separation efficiency in the SSplit unit is 100%, the separation of one stream in the FSplit unit simulates the wind lost by the bypass vent system, and the stream separation ratio is 3%.

In the organic solid waste decomposition subsystem, the subsystem simulates the drying and decomposition processes of the organic solid waste and is respectively realized by a stoichiometric reactor and a yield reactor, wherein the stoichiometric reactor and the yield reactor unit are controlled by a calculator module written by Fortran, and an organic solid waste stream is dried and then is divided by a Sep module to ensure that each type of organic solid waste is independently decomposed into C and H in the yield reactor unit ₂ 、N ₂ 、Cl ₂ 、S、O ₂ 、H ₂ O and inert ASH, decomposition products and 95% of the heat required for decomposition go to the gibbs reactor unit in the decomposition furnace system and 5% to the gibbs reactor unit in the rotary kiln subsystem.

The inner streams of all subsystems are arranged according to different principles: the suspension preheater subsystem is arranged according to the flow direction of gas and solid in the cement production process; the decomposing furnace system and the rotary kiln subsystem modify part of the process sequence on the basis of the actual production process, and the stream firstly passes through a corresponding operation unit for raw material decomposition and then passes through a corresponding operation unit for combustion reaction; the organic solid waste decomposition subsystem is arranged according to the physicochemical reaction process of drying and pyrolysis. The various subsystems are connected with each other through streams, and a steady-state process simulation model formed by the final connection is shown in figure 2.

The steady-state flow simulation model is internally provided with 1 transmission module, 2 design specification modules and 1 sensitivity analysis module, and the decomposing furnace adopts double rows of tertiary air to supply air together and is divided into a row A and a row B. The transmission module copies the volume flow of the A-row tertiary air flow in the air supply of the decomposing furnace to the B-row tertiary air flowAnd (4) flow, namely ensuring that the volume flow of the tertiary air in the row A and the tertiary air in the row B are the same. Design criteria module 1 specifies O in preheater exit flue gas stream ₂ The mole fraction is 0.025, the allowable error is 0.001, the manipulated variable is the tertiary air of the A row of the decomposing furnace, and the variation range is 10 ^-5 -10 ⁶ Nm ³ H; the design specification module 2 specifies that the gibbs reactor outlet stream temperature (simulated decomposition furnace temperature) in the decomposition furnace system is 890 ℃, the allowable error is 0.1 ℃, and the manipulated variable is the decomposition furnace coal stream mass flow. The sensitivity analysis module sets the manipulated variable as the RDF mass flow in the organic solid waste stream, and the output variable as the volume flow and the decomposing furnace coal mass flow under the standard condition of the A-row tertiary air stream in the decomposing furnace system.

(3) Inputting feeding parameters into corresponding streams in the subsystem, wherein the feeding parameters comprise solid feeding parameters and air supply parameters, the solid feeding parameters comprise cement RAW meal, coal powder and RDF, and the components of the cement RAW meal stream (RAW-MATE) are decomposed into CaCO ₃ 、MgCO ₃ And an inert very high fraction (RAW-M) which replaces SiO in the RAW meal ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates. The feeding position of the pulverized coal comprises two positions, namely a decomposing furnace precombustion chamber and a rotary kiln head, and the RDF is taken as a component and is put into an organic solid waste stream to be sequentially dried, decomposed and combusted. The parameter settings for each solids stream are shown in table 1 and the results of the elemental and industrial analyses of coal and RDF are shown in table 2.

Table 1 solid material input parameters

TABLE 2 elemental and industrial analysis results for coal and RDF

* Mar: here and hereafter referred to as received base moisture;

* Fd: herein and hereinafter referred to as dry-based fixed carbon;

* Vd: here and hereafter referred to as dry-based volatiles;

* Ad: dry basis ash is referred to herein and hereinafter.

The air supply parameters comprise three types of air supply of a decomposing furnace, air supply of a rotary kiln and material carrying air, wherein the air supply of the decomposing furnace comprises primary air and double-row tertiary air (AB double rows), the air supply of the rotary kiln comprises primary air and secondary air, cement raw materials enter a preheater and also carry air, and the parameter settings of each air stream are shown in table 3.

TABLE 3 air supply input parameters

^* Standard conditions: here and hereinafter, the standard conditions refer to the conditions of 1atm atmospheric pressure and 0 ℃ and are simply referred to as the standard conditions.

And (4) running simulation, and calculating the calculation data of temperature, flow, components and the like in each subsystem by using a steady-state flow simulation model.

(4) And comparing the temperature data and the flue gas emission data in the suspension preheater subsystem with the measured data of the factory, wherein the comparison results are shown in tables 4 and 5. The relative error between the simulated temperature and the factory measurement data is within 5%, and the model can be considered to be in accordance with the actual production.

TABLE 4 comparison of temperature simulation results with measurement results

TABLE 5 comparison of simulation and measurement results for outlet flue gas

(5) The method comprises the steps of opening a spreadsheet (Excel software) of Microsoft, and establishing a user interaction interface in the spreadsheet, wherein the interaction interface comprises 2 worksheets (sheets), the sheet 1 is used for modifying stream parameters, and the sheet 2 is used for modifying raw material properties. And (3) using a simulation workbook plug-in carried by Aspen software to link the flow parameters and the sensitivity analysis module parameters in the steady-state process simulation model into an Excel table.

(6) The initial parameters of the sheet 1 input stream (shown in the following table 6) in the step 5, the properties of the sheet 2 input raw materials (shown in the following table 7), the lower limit of the input RDF feeding amount of the corresponding cell of the sheet 1 sensitivity analysis module is 80t/h, the upper limit of the feeding amount is 100t/h, the change step size is 1t/h, and the maintaining temperature of the decomposing furnace is 890 ℃, as shown in the following table 6.

Table 6 stream parameters table in spreadsheet from example 1

Table 7 raw material parameters table in spreadsheet from example 1

(7) Clicking the "reset simulation" button and then clicking the "run simulation" button. Obtaining an output result in a result tab of a sensitivity module in Aspen Plus software, analyzing and processing the output result, and quantitatively analyzing the analysis result to maintain the furnace temperature of the decomposing furnace to be 890 ℃ and the O in the outlet flue gas ₂ Under the condition that the volume fraction is 2.5%, the RDF feeding quantity is changed within the range of 80-100t/h, and the influence on the tertiary air volume flow of the decomposing furnace and the coal consumption is realized. The analysis results are shown in the form of a dot line graph, as shown in fig. 4.

Example 2:

the purpose of this example is to study the influence of the change of the water content of the sludge in the range of 10% -90% on the concentration of the smoke pollutants by additionally adding dehydrated sludge for cooperative treatment under the condition that the feeding amounts of the three solids, namely cement raw materials, coal dust and RDF, in the cement kiln are not changed, and the feeding amount of the sludge is 20 t/h. The purpose is realized by the following technical scheme:

(1) The Aspen Plus software is opened, the PR-BM method is selected as the physical property method for calculating the software in the physical property menu, the software database is provided with the conventional components and the solid phase components, and other components which are not contained in the conventional component library and the solid phase component library can be newly established through the entrance of the unconventional components in the software, and the specific properties of the components can be automatically input. Conventional, solid phase components were selected and added from the software database. Selected conventional components have H ₂ O、N ₂ 、O ₂ 、NO ₂ 、NO、S、SO ₂ 、SO ₃ 、H ₂ 、Cl ₂ 、HCl、CO、CO ₂ (ii) a The selected solid phase components are C and CaCO ₃ 、CaO、MgCO ₃ 、MgO、CaSO ₄ (ii) a The new-built components include RDF, sludge, coal, incombustible ash, inert component in cement raw material to replace SiO in cement raw material ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates.

(2) Selecting and adding an operation unit and a stream from a model library of Aspen Plus software, connecting the operation unit and the stream to form 4 subsystems of a suspension preheater, a decomposing furnace, a rotary kiln and organic solid waste decomposition, and connecting the subsystems by using the stream to form a steady-state flow simulation model.

The steady-state flow simulation model building process is substantially the same as the process described in step 2 of example 1, except that the steady-state flow simulation model is used1 design specification module and 1 sensitivity analysis module are arranged in the simulation model, and the design specification module 1 specifies O in the outlet flue gas stream of the preheater ₂ The mole fraction is 0.02, the allowable error is 0.0005, the manipulated variable is the volume flow of the primary air stream of the decomposing furnace, and the variation range is 10 ^-5 -10 ⁶ Nm ³ H; the sensitivity analysis module sets the manipulated variable as the water content of sludge in the organic solid waste stream, and the output variable as SO in the outlet flue gas stream in the suspension preheater subsystem ₂ CO, NO and CO ₂ Mass flow and volume flow under standard conditions of the outlet flue gas stream.

(3) Inputting feeding parameters into a corresponding stream in the subsystem, wherein the feeding parameters comprise solid feeding parameters and air supply parameters, the solid feeding parameters comprise cement RAW meal, coal powder, RDF and sludge, the cement RAW meal only involves carbonate decomposition, other components do not participate in any reaction and only participate in a physical heat exchange process, and therefore, the components of the cement RAW meal stream (RAW-MATE) are decomposed into CaCO ₃ 、MgCO ₃ And an inert very high fraction (RAW-M) which replaces SiO in the RAW meal ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates. The feeding position of the pulverized coal comprises two positions, namely a decomposing furnace precombustion chamber and a rotary kiln head, and the RDF and the sludge are taken as components and are put into an organic solid waste stream to be dried, decomposed and combusted in sequence. The parameter settings for each solids stream are shown in table 8 and the results of elemental and industrial analysis of coal, RDF and sludge are shown in table 9.

TABLE 8 solid Material input parameters

TABLE 9 results of elemental and industrial analyses of coal and RDF

The air supply parameter settings were the same as those described in step 3 of example 1.

And in the factory test measurement data, sludge is not added, so that the mass flow of the sludge components is set to be 0, running simulation is carried out, and a steady-state flow simulation model is used for calculating the calculation data of the temperature, the flow, the components and the like in each subsystem.

(4) The temperature data and the flue gas emission data in the suspension preheater subsystem were compared with the plant data, and the validation results were the same as in step 4 of example 1.

(5) Opening a spreadsheet, and establishing a user interaction interface in the spreadsheet, wherein the interaction interface comprises 2 worksheets (sheets), the sheet 1 is used for modifying the stream parameters, and the sheet 2 is used for modifying the material properties. And (3) linking the flow parameters and the sensitivity analysis module parameters in the steady-state process simulation model into a spreadsheet table by using a simulation workbook plug-in carried by Aspen software.

(6) The sheet 1 inputs stream initial parameters (shown in table 10) in the step 5, the sheet 2 inputs material properties (shown in table 11), the lower limit of the sludge water content input in the corresponding cell of the sheet 1 sensitivity analysis module is 10%, the upper limit is 90%, and the change step length is 5%, as shown in table 10.

Table 10 table of stream parameters for example 2

Table 11 example 2 raw material parameters table (hereinafter example 3 also continues the table)

(7) Clicking the "reset simulation" button and then clicking the "run simulation" button. And obtaining an output result in a result tab of a sensitivity module in the Aspen Plus software, obtaining an output result in a result tab of the sensitivity module in the Aspen Plus software, analyzing and processing the output result, wherein the analysis result shows that the dehydrated sludge is additionally added for synergistic treatment under the condition that the feeding amounts of three solids, namely cement raw meal, coal powder and RDF, are unchanged in the cement kiln, and the influence of the change of the water content of the sludge within the range of 10-90% on the concentration of the smoke pollutants under the condition that the feeding amount of the sludge is 20t/h is shown in figure 5.

Example 3:

the purpose of this example is to investigate the allowable ranges of the feeding amount and water content of sludge if the decomposing furnace temperature is to be kept between 880-905 ℃ and the outlet flue gas temperature is below 360 ℃ under the condition that the feeding amounts of cement raw materials, coal powder and RDF in a cement kiln are not changed and dehydrated sludge is additionally added for cooperative treatment. The purpose is realized by the following technical scheme:

(1) The Aspen Plus software is opened, the PR-BM method is selected as the physical property method for software calculation in the physical property menu, the software database is provided with conventional components and solid phase components, other components which are not contained in the conventional component library and the solid phase component library can be newly established through the entrance of unconventional components in the software, and the specific properties of the components can be input by self. Conventional components, solid phase components, were selected and added from the software database. Selected conventional components have H ₂ O、N ₂ 、O ₂ 、NO ₂ 、NO、S、SO ₂ 、SO ₃ 、H ₂ 、Cl ₂ 、HCl、CO、CO ₂ (ii) a The selected solid phase component is C, caCO ₃ 、CaO、MgCO ₃ 、MgO、CaSO ₄ (ii) a The new-built components include RDF, sludge, coal, incombustible ash, inert component in cement raw material to replace SiO in cement raw material ₂ 、Al ₂ O ₃ 、Fe ₂ O ₃ 、K ₂ O、Na ₂ O、SO ₃ And the like other than carbonates.

The steady-state flow simulation model establishment process is basically the same as the process described in step 2 in the embodiment 1, and the difference is that 1 design specification module and 1 sensitivity analysis module are arranged in the steady-state flow simulation model, and the design specification module 1 specifies O in the preheater outlet flue gas stream ₂ The mole fraction is 0.02, the allowable error is 0.0005, the manipulated variable is the primary air volume flow of the decomposing furnace, and the variation range is 10 ^-5 -10 ⁶ Nm ³ H; the sensitivity analysis module sets the manipulated variables to be the sludge feeding amount and the water content in the organic solid waste stream, and the output variables to be the outlet stream temperature (simulated decomposition furnace temperature) of the Gibbs reactor in the decomposition furnace system and the outlet flue gas stream temperature in the suspension preheater subsystem.

(3) The feed parameters were entered into the corresponding stream in the subsystem, with the same feed parameter settings as described in step 3 in example 2.

(4) The temperature data and the flue gas emission data in the suspension preheater subsystem were compared with the plant data, and the validation results were the same as in step 4 of example 2.

(5) Opening a spreadsheet, and establishing a user interaction interface in the spreadsheet, wherein the interaction interface comprises 2 worksheets (sheets), the sheet 1 is used for modifying the stream parameters, and the sheet 2 is used for modifying the material properties. And (3) using a simulation workbook plug-in carried by Aspen software to link the flow parameters and the sensitivity analysis module parameters in the steady-state process simulation model into an Excel table.

(6) Inputting initial stream parameters (shown in a table 12) in the sheet 1 in the step 5, inputting raw material properties (shown in an upper table 11) in the sheet 2, and inputting the sludge water content of the corresponding unit cell of the sheet 1 sensitivity analysis module, wherein the lower limit value is 10%, the upper limit value is 90%, and the change step length is 5%; the lower limit value of the sludge feeding amount is 1t/h, the upper limit value is 20t/h, and the change step length is 2t/h, as shown in Table 12.

Table 12 stream parameters table in spreadsheet from example 3

(7) Clicking the "reset simulation" button and then clicking the "run simulation" button. And obtaining an output result in a result tab of a sensitivity module in the Aspen Plus software, copying the result into an Excel output result table, and analyzing and processing the data, wherein the analysis result is shown in figure 6. From (a) in fig. 6, it can be known that the outlet flue gas temperature of the preheater and the water content of the sludge are in a negative correlation relationship, the higher the water content of the sludge is, the lower the outlet flue gas temperature is, the rate of the outlet flue gas temperature changing along with the change of the water content of the sludge is gradually increased along with the increase of the feeding amount of the sludge, and when the feeding amount of the sludge is 5t/h and the water content of the sludge is increased from 10% to 90%, the outlet flue gas temperature is reduced from 371.0 ℃ to 357.6 ℃; when the sludge feeding amount is 15t/h and the sludge water content is increased from 10% to 90%, the outlet flue gas temperature is reduced from 391.5 ℃ to 351.9 ℃. As can be seen from (b) in FIG. 6, the temperature of the decomposing furnace and the moisture content of the sludge are in the same negative correlation relationship, the change rule of the temperature of the decomposing furnace is similar to the change rule of the temperature of the flue gas at the outlet of the preheater, and when the feeding amount of the sludge is 5t/h, the moisture content of the sludge is increased from 10% to 90%, the temperature of the flue gas at the outlet is reduced from 922.9 ℃ to 893.8 ℃; when the sludge feeding amount is 15t/h and the sludge water content is increased from 10% to 90%, the outlet flue gas temperature is reduced from 949.3 ℃ to 864.5 ℃. Compared with the influence of the change of the water content of the sludge on the temperature of the flue gas at the outlet of the preheater, the influence of the water content of the sludge on the temperature of the decomposing furnace is more severe.

Under the condition that the feeding amounts of three solids, namely cement raw materials, coal powder and RDF, in a cement kiln are not changed, if the temperature of a decomposing furnace is required to be maintained between 880 ℃ and 905 ℃, the temperature of outlet flue gas is below 360 ℃, and the feeding amount of sludge is 7.2t/h, the allowable range of the water content of the sludge can reach the maximum: 55 to 90 percent; when the sludge feeding amount is 20t/h, the water content of the sludge needs to be limited in a narrow range: 67% -69%.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A simulation and optimization method for a cement kiln co-processing organic solid waste process is characterized by comprising the following steps:

a suspension preheater subsystem: the system is used for suspension preheater equipment in cement production, wherein the streams are arranged according to the flow directions of gas and solid in the cement production process;

decomposition furnace system: the decomposing furnace equipment used in cement production comprises a raw material decomposition corresponding operation unit and a combustion reaction corresponding operation unit; the stream in the decomposing furnace system is arranged according to the operation unit corresponding to the raw material decomposition in the decomposing furnace system firstly and the operation unit corresponding to the combustion reaction in the decomposing furnace system secondly; wherein the operation unit corresponding to the combustion reaction is a Gibbs reactor (RGibbs) operation unit;

a rotary kiln subsystem: the rotary kiln equipment is used for corresponding to cement production and comprises a raw material decomposition corresponding operation unit and a combustion reaction corresponding operation unit; the stream in the rotary kiln subsystem is arranged according to the operation unit corresponding to the decomposition of the raw material in the rotary kiln subsystem and the operation unit corresponding to the combustion reaction in the rotary kiln subsystem; wherein the operation unit corresponding to the combustion reaction is a Gibbs reactor operation unit;

the design specification module: the steady-state flow simulation model is used for controlling a variable in the steady-state flow simulation model to be a specified value or a specified range;

the feeding parameters comprise the type of the feeding stream and the parameters of the feeding stream; wherein the feed stream species comprise: adding different raw materials, different fuels and air into the cement kiln; feed stream parameters included: mass flow, temperature and chemical composition;

2. The method according to claim 1, wherein said step (S5) comprises in particular the sub-steps of:

3. The method according to claim 1, wherein in the step (S2), the suspension preheater subsystem is divided into five stages from top to bottom, i.e., C1-C5, and four processes of gas-solid mixed heat exchange, carbonate decomposition, surface heat dissipation and gas-solid separation, which are generated in a suspension preheater device in cement production, are respectively realized by a Mixer (Mixer) operation unit, a stoichiometric reactor (RStoic) operation unit, a heat exchanger (Heater) operation unit and an SSplit operation unit; the C1 stage comprises a mixer operation unit, a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams; each C2-C4 stage comprises a mixer operation unit, a chemical meter reactor operation unit, a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams; the C5 stage comprises a heat exchanger operation unit and an SSplit operation unit which are connected in sequence by material streams;

for any one heat exchanger (Heater) operating unit, their thermal loads are preset to-1.0X 10 ⁷ to-3.0X 10 ⁶ kJ/h；

The SSplit operation units are used for splitting, each SSplit operation unit comprises 2 outlets, wherein a stream split from the outlet positioned above the operation unit is recorded as an upper stream, and a stream split from the outlet positioned below the operation unit is recorded as a lower stream; for any SSplit operation unit, the gas flow directions of the SSplit operation units are preset as follows: 93% -95% enter the upper stream, and the solid flow directions of the upper stream and the upper stream are preset as follows: 87% -96% of the liquid enters a lower material flow; wherein the upper stream of the SSplit operation units in the C1 stage is not connected to any operation unit, the upper stream of the SSplit operation units in the C2-C5 stage enters the mixer operation unit of the previous stage suspension preheater; the lower stream of the SSplit operation unit in the C1-C3 stage enters a mixer operation unit of a next stage suspension preheater, the lower stream of the SSplit operation unit in the C4 stage enters a Gibbs reactor operation unit in the decomposing furnace system, and the lower stream of the SSplit operation unit in the C5 stage enters a Gibbs reactor operation unit in the rotary kiln subsystem;

all feed streams in the suspension preheater subsystem are connected to the mixer operating unit in the C1 stage, the feed streams simultaneously comprising a cement raw stock stream, a raw meal carrying air stream; the outlet stream in the suspension preheater subsystem simultaneously comprises an upper stream from the SSplit process unit in the C1 stage and a lower stream from the SSplit process unit in the C5 stage.

4. The method according to claim 1, wherein in the step (S2), the decomposing furnace system is used for simulating pulverized coal decomposition, combustion reaction, carbonate decomposition and surface heat dissipation processes, which are respectively realized by hot streams connected with a yield reactor (RYield) operating unit, a gibbs reactor (RGibbs) operating unit, a stoichiometric reactor operating unit and a stoichiometric reactor operating unit; wherein the yield reactor operating unit, the Gibbs reactor operating unit and the stoichiometric reactor operating unit are connected in sequence;

a yield reactor operating unit controlled by the calculator module;

A feed stream in the decomposition furnace system is connected to a yield reactor operation unit, the feed stream being a material stream of decomposition furnace coal; an outlet stream in the decomposition furnace system, which is the outlet stream of the stoichiometric reactor operating unit, is connected to the heat exchanger operating unit of the C5 stage in the suspension preheater subsystem.

5. The method according to claim 1, wherein in step (S2), the rotary kiln subsystem is used for simulating pulverized coal decomposition, combustion reaction, carbonate decomposition, surface heat dissipation, gas-solid separation and bypass ventilation processes, and comprises a yield reactor operation unit, a mixer operation unit, a gibbs reactor operation unit, a stoichiometric reactor operation unit, a heat exchanger operation unit, an SSplit operation unit and an FSplit operation unit which are connected in sequence; wherein, the processes of simulating coal powder decomposition, combustion reaction, carbonate decomposition and surface heat dissipation are respectively realized by using a productive reactor operation unit, a Gibbs reactor operation unit, a stoichiometric reactor operation unit and a heat exchanger operation unit; the simulation of the gas-solid separation and the bypass ventilation process are realized by using an SSplit operation unit and an FSplit operation unit respectively;

a stoichiometric reactor operating unit for defining a decomposition reaction of calcium carbonate and magnesium carbonate, the decomposition rate being set to 100% in advance;

The gas-solid separation efficiency in the SSplit operation unit is preset to be 100%;

separating a stream from the FSplit operation unit to simulate the wind lost by a bypass air bleeding system, and recording as a bypass air bleeding stream, wherein the separation ratio of the bypass air bleeding stream is preset to be 3% -5%;

the number of feed streams in the rotary kiln subsystem is 4, and the feed streams specifically comprise rotary kiln coal, kiln inlet clean air, primary air and secondary air; wherein the rotary kiln coal stream is connected to a yield reactor operation module; the three streams of in-kiln net air, primary air and secondary air are combined by the mixer operation unit into a single stream which is then connected to the gibbs reactor operation module; the number of outlet streams is 3, and the outlet streams are respectively as follows: the lower material stream in the SSplit operation unit is used as a cement clinker outlet stream and is not connected with any operation unit; a bypass air discharge stream in the FSplit operation unit is not connected with any operation unit; and connecting other streams except the bypass vent stream in the FSplit operation unit to the mixer operation unit in the organic solid waste decomposition subsystem.

6. The method according to claim 1, wherein in the step (S2), the organic solid waste decomposition subsystem comprises a mixer operation unit, a stoichiometric reactor operation unit, a Sep operation unit, a yield reactor operation unit, a mixer operation unit and an FSplit operation unit which are connected in sequence; the organic solid waste decomposition subsystem is used for simulating the drying and decomposition processes of the organic solid waste and is respectively realized by a stoichiometric reactor operation unit and a yield reactor operation unit; wherein, the first and the second end of the pipe are connected with each other,

after passing through a stoichiometric reactor operation unit, organic solid waste streams are divided by a Sep operation unit, so that each type of organic solid waste is independently decomposed in a yield reactor operation unit, decomposition products and heat required by decomposition are respectively combined into a material stream and a heat stream by a mixer unit, 2 streams are divided by FSplit operation units, the division ratio is preset to be 95;

and in the organic solid waste decomposition subsystem, the number of the operation units of the yield reactor is 5-15, and the number of the operation units of the FSplit reactor is 2;

the total number of feed streams in the organic solid waste decomposition subsystem is 4, and the feed streams specifically comprise organic solid waste, primary air, A-row tertiary air and B-row tertiary air; wherein the organic solid waste stream is connected to a stoichiometric reactor operation unit; the primary air, the A row of tertiary air and the B row of tertiary air are mixed by the mixer operation unit and then are connected to the productivity reactor operation unit; the number of outlet streams is 4, and the outlet streams specifically comprise 2 material flow streams and 2 heat flow streams which are divided by 2 FSplit operation units, wherein 1 material flow stream with the division ratio of 95% and 1 heat flow stream with the division ratio of 95% enter a Gibbs reactor operation unit in a decomposition furnace system, and 1 material flow stream with the division ratio of 5% and 1 heat flow stream with the division ratio of 5% enter the Gibbs reactor operation unit in a rotary kiln subsystem.

7. The method according to claim 1, wherein in the step (S1), the physical property method is selected from the group consisting of PR-BM method;

the chemical components are pre-classified into three categories, namely: conventional components, solid phase components, and unconventional components; the conventional component and the solid-phase component are obtained by selecting from a software database, and the unconventional component is obtained by newly building;

8. The method according to claim 1, wherein in the step (S5-1), the interactive interface is implemented by Excel software, MATLAB software, software written in Python language, or software capable of implementing ActiveX technology connection;

preferably, the interactive interface comprises at least two interfaces, wherein one interface is used for inputting the value or the variation range of the feeding parameter, and the other interface is used for inputting the properties of the coal and the organic solid wastes; the properties of the coal and the organic solid wastes simultaneously comprise industrial analysis data, element analysis data and dry-basis low calorific value: wherein the industrial analysis data simultaneously comprises the content of application-based moisture, the content of dry-based ash, the content of dry-based volatile components and the content of dry-based fixed carbon; the element analysis data simultaneously comprises C content, H content, O content, N content, S content and Cl content;

9. The method according to claim 1, wherein in the step (S5), it is determined whether to adjust the improvement process based on the calculation result, specifically, based on the calculation result of the temperature of the cement kiln equipment, the calculation result of the volume of discharged flue gas, the calculation result of the concentration of flue gas components, the calculation result of coal consumption, or the calculation result of the proportion of organic solid waste mixed combustion.

10. The method of claim 1, wherein in step (S4), the absolute value of the preselected acceptance limit is preselected to be between 4% and 6%.