CN107880959A - Chemical chain reforms methane system processed - Google Patents

Abstract

The invention relates to the field of methane production by chemical chain reforming, and is an efficient and clean chemical chain methane production system. The invention is mainly composed of a hydrogen permeable membrane reaction generator, a chemical chain reforming reaction generator, a chemical chain combustion reaction generator, a heat exchanger, and a liquid oxygen storage device. The reaction substance water gas is used to pass it into the hydrogen permeable membrane The reaction generator produces hydrogen, carbon monoxide and part of water vapor, passes the generated hydrogen into the chemical chain combustion reaction generator, passes carbon monoxide and part of water vapor into the chemical chain reforming reaction generator, and completes the reaction through a series of separation and coupling processes , producing methane. The invention integrates devices such as an air reactor and a fuel reactor to improve the reaction rate, fuel utilization rate and system economy, and has good practical significance.

Description

Chemical Looping Reforming Methane System

technical field

The invention relates to the field of methane production by chemical chain reforming, and is an efficient and clean chemical chain methane production system.

Background technique

Chemical chain combustion is flameless combustion. Its main principle is to transform the traditional direct contact between fuel and oxygen into the process of reacting with fuel and air with the help of oxygen carrier. The fuel is no longer in direct contact with oxygen, but with the help of oxygen carrier. , the oxygen in the air is brought into the fuel in the form of oxygen atoms in the oxide to react.

Coal chemical chain methane is of great significance to the conversion and utilization of clean energy. There is a waste of materials in the traditional methane production process. In view of this drawback, a recyclable reaction process is designed to reduce Material waste. Chemical chaining is a new type of environmentally friendly and efficient energy conversion and utilization technology. It provides an important way for coal chemical chaining methane production. It is of great significance to changing the traditional methane production and overcoming the disadvantages of traditional production. The clean utilization and efficient utilization provide new ideas. And through this method, the terminal energy structure can be optimized. With environmental protection, how to use energy efficiently has become an important issue that needs to be deeply discussed and solved today and even in the future. Therefore, the study of a chemical chain methane chemical process is in line with the development law of the times. We use water gas as raw material to study the chemical process based on coal chemistry. Chain methane process, and adopt a new reaction process to achieve.

Contents of the invention

Hydrogen production is carried out through the reaction of water-gas shift membrane hydrogen production. Water gas is separated from CO and H ₂ through the membrane, and the separated hydrogen is passed into the coal chemical chain reaction to synthesize CH ₄ . The remaining CO is directly passed into the combustion chamber, and then Pass the produced CH ₄ into the combustion chamber for combustion, so that CH ₄ with good purity can be obtained through the coal chemical chain reaction, avoiding insufficient combustion caused by direct combustion of coal, thereby improving combustion efficiency and avoiding direct combustion unfavorable factors.

Through the analysis of the factors affecting the conversion rate in the hydrogen permeable membrane reactor, the SiO ₂ membrane equipped with methyl groups is used to produce hydrogen.

The device mainly includes: a hydrogen permeable membrane reaction generator, a chemical chain reforming reaction generator, a chemical chain combustion reaction generator, a heat exchanger, and a liquid oxygen storage tank. The hydrogen membrane reaction generator produces hydrogen, carbon monoxide and part of the water vapor, passes the generated hydrogen into the chemical chain combustion reaction generator, passes the carbon monoxide and part of the water vapor into the chemical chain reforming reaction generator, and passes through a series of separation and coupling processes Generate organic gases such as methane, and the generated water vapor passes through the chemical chain reforming reaction generator to generate hydrogen and some oxygen ions, which realizes the recycling of water vapor, and passes the generated organic combustibles such as methane through the heat exchanger into chemical chain combustion Reaction generators for energy conversion. And the generated oxygen-rich ions pass through the oxygen carrier and pass into the combustion reaction chamber for energy transfer and transformation. The schematic diagram of the system principle is shown in Figure 1.

(1) Hydrogen permeable membrane reaction generator

Hydrogen is produced through the water-gas shift membrane hydrogen production reaction. Water gas separates CO and H ₂ through the membrane, and passes the separated hydrogen into the coal chemical chain reaction to synthesize CH ₄ . The remaining CO is directly passed into the combustion chamber, and then Pass the produced CH ₄ into the combustion chamber for combustion, so that CH ₄ with good purity can be obtained through the coal chemical chain reaction, avoiding insufficient combustion caused by direct combustion of coal, thereby improving combustion efficiency and avoiding direct combustion unfavorable factors.

(2) Chemical chain reformation reaction generator

The purpose is to provide a process for producing methane and hydrogen based on chemical loop gasification with low cost, high energy conversion rate and high hydrogen production efficiency. Chemical chain hydrogen production is a new type of high-efficiency hydrogen production technology. In this process, the sensible heat carried by the oxygen carrier can provide the heat required for the gasification reaction, and realize the heat transfer from the exothermic reactor to the endothermic reaction. The circulation of oxygen carriers, the process of chemical looping hydrogen production can realize the transfer of oxygen from air to water vapor, and at the same time decompose water into hydrogen and oxygen ions, the reaction of CO and hydrogen to synthesize methane and water, the hydrogenation and gasification of CO, and the catalytic production of chemical looping The coupling of hydrogen and organic can realize the production of hydrogen and methane from coal and reduce the emission of pollutants.

(3) Chemical looping combustion reaction generator

The reduction of greenhouse gas CO ₂ emissions has become the focus of the world. The reduction of CO ₂ emissions can be achieved by improving the conversion rate and utilization efficiency of energy. Nowadays, fossil fuels will still be the main energy used. Through conventional combustion flue gas It is very difficult to capture CO ₂ , so it must be solved from the source or the process. This plan will adopt the chemical looping combustion technology from the process to reduce CO ₂ emissions, so as to achieve the purpose of energy saving and emission reduction. The chemical looping combustion technology has the inherent ability to capture CO ₂ capacity, and does not require additional energy consumption, so it is a new technology to achieve efficient and clean utilization, with broad development prospects. The chemical looping combustion reaction in the combustion chamber is:

CH ₄ (g) + H ₂ O (g) → CO (g) + 3H ₂ (g) (2.1)

CO (g) + H ₂ O (g) → CO ₂ (g) + H ₂ (g) (2.2)

(4) Heat exchanger

The devices used to transfer heat from hot fluid to cold fluid to meet the specified requirements are collectively called heat exchangers. According to the working status of heat exchangers, they can be divided into three types: partition type, hybrid type, and heat storage type. The most widely used is the partition wall type, the main form of the partition wall heat exchanger is the casing type, the shell and tube heat exchanger, and the cross type heat exchanger. We use the partition wall heat exchanger (as shown in Figure 2) to exchange hot.

The role of the memory is to store oxygen.

Description of drawings

Figure 1 is a schematic diagram of the principle of the chemical looping reforming methane system, Figure 2 is a two-dimensional schematic diagram of a partitioned wall heat exchanger, and Figure 3 is a schematic reaction diagram of the chemical looping reforming methane system.

Detailed ways

Parameter Design of Heat Exchanger

The parameters of the heat exchanger are designed as follows: the inlet water temperature of the heat exchanger is set at 20°C, and the outlet water temperature is set at 60°C. The heat transfer oil at the inlet of the heat exchanger is 250°C, and the temperature of the heat transfer oil at the outlet is 200°C; the volumetric flow rate measured by the water of the heat exchanger is 12L/min.

In this design calculation, the average temperature difference method is used for the design calculation of the heat exchanger.

The calculation process is as follows:

This design adopts a shell-and-tube heat exchanger with 1 pass on the shell side and 4 passes on the tube side. The outer diameter of the heat exchange tube is 51mm and the wall thickness is 1mm.

Ψ=0.98

Check the data to get:

Oil side surface heat transfer coefficient h ₀ ＝450w/m ² gk

Water side surface heat transfer coefficient h _i ＝5850w/m ² gk

Thermal resistance value of fouling in the pipe R ₀ =0.000176m ² gk/w

Thermal resistance value of fouling outside the tube R _i ＝0.000352m ² gk/w

The actual design takes 10% margin:

A＝A ₀ ×1.1＝1.45m ²

advantage analysis

This new type of chemical chain reaction overcomes the drawbacks of traditional combustion and reforming reactions and reduces pollutant emissions. The chemical chain reforming reaction increases the conversion rate of the reactants, transforms them into cleaner and more efficient products, and facilitates the combustion reaction process. Compared with the traditional combustion method, the chemical looping combustion reaction has its unique combustion method and the pollution it produces is unattainable by the traditional method. It has the characteristics of low pollution and high production capacity.

For the innovative point of hydrogen permeable membrane reaction, it has the characteristics of separating specific products according to requirements and high conversion rate. Compared with the traditional conversion method, it is convenient and simple, with high conversion rate. The conversion product has high purity, which is beneficial to other reaction processes. , which has a certain improvement effect on the reaction transformation process of the whole system.

Claims (3)

1. Chemical looping reforming methane system, the system includes: hydrogen permeable membrane reaction generator, chemical looping reforming reaction generator, chemical looping combustion reaction generator, heat exchanger, liquid oxygen storage. 2. The chemical looping reforming methane system according to claim 1, characterized in that the system comprises a hydrogen permeable membrane reaction generator, the principle of which is to produce hydrogen through the reaction of water gas shift membrane hydrogen production, process flow It is the water gas that separates CO and H2 through the membrane, passes the separated hydrogen into the coal chemical chain reaction to synthesize CH4, and passes the remaining CO directly into the combustion chamber, and then passes the produced CH4 into the combustion chamber for combustion. 3. chemical looping reforming methane system according to claim 1, is characterized in that, described system comprises chemical looping reforming reaction generator, carbon monoxide and part water vapor pass into chemical looping reforming reaction generator, through separating The coupling process generates organic gases such as methane.