Hydrogen-rich blast furnace ironmaking system based on mass-energy conversion, and production control method therefor

Abstract

A hydrogen-rich blast furnace ironmaking system based on mass-energy conversion, comprising a water electrolysis system (2). The water electrolysis system (2) is separately connected to a hydrogen storage tank (3) and an oxygen storage tank (4); a gas outlet of the hydrogen storage tank (3) is connected to a hydrogen compressor (5); an outlet of the hydrogen compressor (5) is connected to a hydrogen buffer tank (6); the hydrogen buffer tank (6) is connected to a hydrogen injection valve group (7); the hydrogen injection valve group (7) is connected to a hydrogen preheating system (8); and the hydrogen preheating system (8) is connected to a tuyere of a blast furnace body (1) or a hydrogen injector at the lower portion of the furnace body.

Claims

1. A production control method for a hydrogen-rich blast furnace ironmaking system based on energy-mass conversion, the hydrogen-rich blast furnace ironmaking system including a blast furnace and an electrolyzed water system; the electrolyzed water system being respectively connected to a hydrogen gas storage tank and an oxygen gas storage tank; a gas outlet of the hydrogen gas storage tank being connected to a hydrogen compressor; an outlet of the hydrogen compressor being connected to a hydrogen buffer tank; the hydrogen buffer tank being connected to a hydrogen injection valve group; the hydrogen injection valve group being connected to a hydrogen pre-heating system; the hydrogen pre-heating system being connected to a tuyere of the blast furnace or a hydrogen injection device at a lower part of the blast furnace; a gas outlet of the oxygen gas storage tank being connected to an oxygen injection valve group, and the oxygen injection valve group being connected to a cold air main pipe of the blast furnace; the system also including a hydrogen injection quantity calculation and control system, and control signals of the hydrogen injection quantity calculation and control system being connected to the electrolyzed water system, the hydrogen injection valve group, and the oxygen injection valve group through signal transmission lines; the production control method comprising the steps of: starting the electrolyzed water system to transport hydrogen and oxygen obtained after electrolysis to the hydrogen gas storage tank and the oxygen gas storage tank, respectively; pressuring the hydrogen in the hydrogen gas storage tank with the hydrogen compressor and then letting the pressured hydrogen into the hydrogen buffer tank; after adjusting pressure and flow with the hydrogen injection valve group, pre-heating the hydrogen in the hydrogen pre-heating system; injecting the pre-heated hydrogen into the blast furnace through the hydrogen injection device; and after the hydrogen injection quantity calculation and control system implements a calculation formula for the economic benefit of hydrogen injection to determine the hydrogen injection quantity that maximizes the current benefit per ton of iron, synchronously controlling the hydrogen production power of the electrolyzed water system and the hydrogen injection quantity into the blast furnace through control signals; wherein the calculation formula for the economic benefit of hydrogen injection is as follows: $B=\frac{M_0-M}{1000}{P}_M+\frac{K_0-K}{1000}{P}_K+\frac{V_{\mathrm{BF}}-{}_0{V}_{\mathrm{BF}}}{V_{\mathrm{BF}}}{P}_{\mathrm{PI}}+\left(C_0-C\right)P_{{\mathrm{CO}}_2}+\left(E_0-E\right)-H{P}_{H_2};$ in the formula: B: the benefit per ton of iron after hydrogen injection into the blast furnace under the current market conditions, with the unit of yuan per ton of iron (yuan/t); M.sub.0: the coal ratio without hydrogen injection, with the unit of kilograms per ton of iron (kg/t); M: the coal ratio with hydrogen injection, with the unit of kilograms per ton of iron (kg/t); P.sub.m: the price of the injected pulverized coal, with the unit of yuan per ton of iron (yuan/t); K.sub.0: the coke ratio without hydrogen injection, with the unit of kilograms per ton of iron (kg/t); K: the coke ratio with hydrogen injection, with the unit of kilograms per ton of iron (kg/t); P.sub.k: the price of the charged coke, with the unit of yuan per ton of iron (yuan/t); .sub.0: the utilization coefficient of the blast furnace without hydrogen injection, with the unit of tons per cubic meter per day [t/(m.sup.3.Math.d)]; : the utilization coefficient of the blast furnace with hydrogen injection, with the unit of tons per cubic meter per day [t/(m.sup.3.Math.d)]; VBF: the effective volume of the blast furnace, with the unit of cubic meters (m.sup.3); PPI: the profit per ton of iron, with the unit of yuan per ton (yuan/t); C.sub.0: the direct CO.sub.2 emission without hydrogen injection, with the unit of tons per ton of iron (t/t); C: the direct CO.sub.2 emission with hydrogen injection, with the unit of tons per ton of iron (t/t); PCO.sub.2: the carbon-emission trading price, with the unit of yuan per ton of iron (yuan/t); E.sub.0: the operating cost of environmental protection facilities per ton of iron without hydrogen injection, with the unit of yuan per ton of iron (yuan/t); E: the operating cost of environmental protection facilities per ton of iron with hydrogen injection, with the unit of yuan per ton of iron (yuan/t); P.sub.h.sub.2: the production price of hydrogen, with the unit of yuan per standard cubic meter (yuan/Nm.sup.3); H: the hydrogen injection volume, with the unit of standard cubic meters per ton of iron (Nm.sup.3/t).

2. The production control method according to claim 1, further comprising the step of: after adjusting the pressure and flow rate of the oxygen in the oxygen storage tank by the oxygen injection valve group, injecting the oxygen into the blast furnace through the cold air main pipe.

3. The production control method according to claim 1, wherein the electrolyzed water system is powered by electricity generated by photovoltaic solar panels, off-peak electricity from a power grid, or wind energy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a hydrogen injection system for a hydrogen-rich blast furnace in a preferred embodiment of the present invention.

(2) Reference numerals: 1Blast furnace body; 2Water-electrolysis hydrogen-production system; 3Hydrogen gas storage tank; 4Oxygen gas storage tank; 5Hydrogen compressor; 6Hydrogen buffer tank; 7Hydrogen injection valve group; 8Hydrogen pre-heating system; 9Oxygen injection valve group; 10Economic hydrogen-injection quantity calculation and control system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(3) A plurality of preferred embodiments of the present invention are described below with reference to the drawings, which makes its technical content more clear and convenient to understand. The present invention may be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments set forth herein.

(4) As shown in FIG. 1, in this embodiment, the hydrogen-injection system for a hydrogen-rich blast furnace and its production control method according to the present invention are applied to a blast furnace with an effective volume of 1780 m.sup.3, including a 1780-m.sup.3 blast furnace body, an electrolyzed water system with a hydrogen-production capacity of 35000 m.sup.3/h, a 50-m.sup.3 hydrogen gas storage tank, an oxygen gas storage tank, a hydrogen compressor, a 50-m.sup.3 hydrogen buffer tank with a pressure resistance of 20 MPa, a hydrogen injection valve group, a hydrogen pre-heating system capable of heating up to 1000 C., an oxygen injection valve group, and an economic hydrogen-injection quantity calculation and control system.

(5) The hydrogen (H.sub.2) produced by the electrolyzed water system 2 is transported through pipeline P1 to the hydrogen gas storage tank 3, and the produced oxygen is transported through pipeline P2 to the oxygen gas storage tank 4. The gas outlet of the hydrogen gas storage tank 3 is connected via pipeline P3 to the low-pressure interface of the hydrogen compressor 5. After pressurization, the hydrogen exits from the high-pressure interface of the hydrogen compressor 5 and is connected through pipeline P4 to the inlet of the hydrogen buffer tank 6. The outlet of the hydrogen buffer tank 6 is connected via pipeline P5 to the hydrogen injection valve group 7. After the pressure and flow of the hydrogen are adjusted, it is connected through pipeline P6 to the hydrogen pre-heating system 8. After the hydrogen is heated to the set temperature, it is transported through pipeline P7 to the tuyere of the blast furnace body 1 or the hydrogen injection device at the lower part of the furnace shaft. The gas outlet of the oxygen gas storage tank 4 is connected via pipeline P8 to the oxygen injection valve group 9. After the pressure and flow of the oxygen are adjusted, it is connected through pipeline P9 to the cold air main pipe of the blast furnace body 1. The control signals of the economic hydrogen-injection quantity calculation and control system are connected through signal transmission lines to the electrolyzed water system 2, the hydrogen injection valve group 7, and the oxygen injection valve group 9.

(6) The specific implementation steps include: Step 1: After the blast furnace being operating smoothly, starting the water-electrolysis hydrogen-production equipment. From 8:00 to 18:00, it being powered by the electricity produced by photovoltaic solar panels, and for the rest of the time, it being powered by off-peak electricity from the power grid or wind energy to produce hydrogen and oxygen and inject them into the blast furnace. The injection volume starting from zero and increasing step by step, with an adjustment step of 25 Nm.sup.3/t of iron. At the same time, the existing operating process parameters of the blast furnace needing to be adjusted. On the premise of ensuring the smooth operation of the blast furnace, the qualification of product quality, and the safe operation of equipment, the maximum carbon reduction and optimal economic benefits being achieved. The blast furnace operation time for each adjustment step of the hydrogen injection volume being 15 days, and the maximum hydrogen injection volume being set to 250 Nm.sup.3/t of iron. Step 2: After 150 days of hydrogen injection operation in the blast furnace, recording the optimal operating parameters and their corresponding operation parameters (including but not limited to hydrogen injection volume, oxygen enrichment rate, coal ratio, blast volume, charging systems of coke and iron-containing materials, etc.) under different hydrogen injection volumes, and establishing a database of operating parameters for the hydrogen-rich blast furnace. Step 3: Inputting the real-time fluctuating prices of raw materials and fuels, hydrogen price, carbon emission tax, and product price into the economic hydrogen-injection quantity calculation model. Through the calculation formula for the economic benefit of hydrogen injection, obtaining the benefit per ton of iron corresponding to different hydrogen-injection quantities in the current market. By comparison, obtaining the hydrogen-injection quantity that maximizes the benefit per ton of iron, which is the economic hydrogen-injection quantity. Synchronously adjusting the hydrogen-production power of the water-electrolysis hydrogen-production system and the hydrogen-injection quantity into the blast furnace.

(7) The calculation formula for the economic benefit of hydrogen injection is as follows:

(8) $B=\frac{M_0-M}{1000}{P}_M+\frac{K_0-K}{1000}{P}_K+\frac{V_{\mathrm{BF}}-{}_0{V}_{\mathrm{BF}}}{V_{\mathrm{BF}}}{P}_{\mathrm{PI}}+\left(C_0-C\right)P_{{\mathrm{CO}}_2}+\left(E_0-E\right)-H{P}_{H_2}$

(9) In the formula: B: The benefit per ton of iron after hydrogen injection into the blast furnace under the current market conditions, with the unit of yuan per ton of iron (yuan/t); M.sub.0: The coal ratio without hydrogen injection, with the unit of kilograms per ton of iron (kg/t); M: The coal ratio with hydrogen injection, with the unit of kilograms per ton of iron (kg/t); P.sub.m: The price of the injected pulverized coal, with the unit of yuan per ton of iron (yuan/t); K.sub.0: The coke ratio without hydrogen injection, with the unit of kilograms per ton of iron (kg/t); K: The coke ratio with hydrogen injection, with the unit of kilograms per ton of iron (kg/t); P.sub.k: The price of the charged coke, with the unit of yuan per ton of iron (yuan/t); .sub.0: The utilization coefficient of the blast furnace without hydrogen injection, with the unit of tons per cubic meter per day [t/(m.sup.3.Math.d)]; : The utilization coefficient of the blast furnace with hydrogen injection, with the unit of tons per cubic meter per day [t/(m.sup.3.Math.d)]; VBF: The effective volume of the blast furnace, with the unit of cubic meters (m.sup.3); PPI: The profit per ton of iron, with the unit of yuan per ton (yuan/t); C.sub.0: The direct CO.sub.2 emission without hydrogen injection, with the unit of tons per ton of iron (t/t); C: The direct CO.sub.2 emission with hydrogen injection, with the unit of tons per ton of iron (t/t); PCO.sub.2: The carbon-emission trading price, with the unit of yuan per ton of iron (yuan/t); E.sub.0: The operating cost of environmental protection facilities per ton of iron without hydrogen injection, with the unit of yuan per ton of iron (yuan/t); E: The operating cost of environmental protection facilities per ton of iron with hydrogen injection, with the unit of yuan per ton of iron (yuan/t); P.sub.h.sub.2: The production price of hydrogen, with the unit of yuan per standard cubic meter (yuan/Nm.sup.3); H: The hydrogen injection volume, with the unit of standard cubic meters per ton of iron (Nm.sup.3/t).

(10) Preferred embodiments of the present invention are described in detail above. It should be understood that many modifications and variations can be made to the concepts of the present invention without creative efforts by those of ordinary skill in the art. Therefore, it would be obvious to a person skilled in the art to arrive at the technical solutions of the present invention by means of logical analysis, reasoning, or limited experiments on the basis of the prior art, all within the scope of protection defined by the claims.