Discussion on waste heat utilization of glass kiln

2022-08-24
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Energy conservation and environmental protection: talking about the waste heat utilization of glass kiln flue gas

on July 21, the 8th International Summit on waste heat utilization 2012 was grandly opened in the beautiful coastal city of Dalian. Wangzongwei, deputy chief engineer of China Building Materials International Engineering Co., Ltd., introduced to the attendees that the glass kiln flue gas waste heat tensile testing machine is applicable to the stretching, peeling, deformation, tearing, heat sealing, bonding, puncture force, opening force of plastic film, composite materials, adhesives, adhesive tapes, self-adhesive, medical patches, protective films, release papers, backplane materials, rubber, paper fibers and other products The following is the report on the utilization of low-speed unwinding force and other performance tests

1. Current situation of float glass in China

China's flat glass industry has a history of nearly 30 years since it successfully developed and led float glass production lines. By the end of 2011, China had put into operation more than 240 float glass production lines, with an output of 738 million heavy containers, accounting for more than 50% of the global output

2. Energy consumption of float glass in China

take a typical float glass furnace as an example, its energy consumption is:

3 Energy saving ways of float glass furnace

1) strengthen heat preservation and kiln body sealing, reduce surface heat dissipation, etc

2) adopt the method of full oxygen combustion or oxygen enriched combustion to reduce the amount of flue gas leaving the glass furnace and the residual heat of flue gas by reducing the entry of nitrogen that is helpless for combustion into the kiln

3) strengthen the recovery and utilization of the heat carried by the flue gas leaving the glass furnace

4) adopt large tonnage glass furnace to improve the melting rate

5) improve the kiln design

among them, the most important thing is the huge potential of flue gas heat recovery

4. Utilization status of heat carried by flue gas

at present, there are mainly several methods of waste heat utilization of flue gas: direct use of steam, waste heat power generation, waste heat heating batch or other carriers, etc

(1) steam production

in the past, the main purpose of steam was heating and heating. Now, lithium bromide units can be used for refrigeration, but due to the influence of usage, usage time and season, this method alone often cannot make full use of the waste heat in flue gas

(so as to alleviate the increasingly serious problem of sustainable development of people and the environment. 2) waste heat power generation

using waste heat from glass furnaces to generate electricity is a comprehensive resource utilization project. While making full use of waste heat, it can not only greatly improve the energy utilization rate of the whole plant, but also reduce the emission of air pollutants generated by thermal power generation and reduce the greenhouse effect

(3) waste heat heating batch or other carriers

using flue gas to heat glass batch or broken glass has been a long-term research topic in various countries. Heating broken glass has been applied, and it is difficult to heat batch

at present, our company is doing the work of gas gas heat exchange, using flue gas to heat air or coke oven gas

5. Float glass flue gas waste heat power generation

waste heat power generation system essentially uses the waste heat boiler to recover the heat energy in the waste gas, produce superheated steam, and then send it to the steam turbine for expansion to do work, convert the heat energy into mechanical energy, and then drive the generator to generate electricity

since 2007, China's leading glass kiln waste heat power stations have been put into use. At present, dozens of power stations are under construction and operation across the country, and their development process is very rapid. Major glass enterprises have basically built waste heat power stations, and many of them use BOT

due to the characteristics and requirements of glass production, the following factors must be considered for power generation from waste heat of glass furnace flue gas:

1) ensure smooth smoke exhaust and safe operation of glass furnace

2) ensure the stability of the pressure in the glass kiln, and the kiln pressure should fluctuate within ± 0.5pa

3) adapt to the working characteristics of frequent reversing of glass kiln

4) it is necessary to fully understand that the parameters (temperature, flow, pressure) of waste heat of exhaust gas have certain Volatility:

5) China's glass enterprises use more petroleum coke powder, with an average sulfur content of 2 ~ 3%, and its combustion products contain a large number of corrosive (acidic) gases and putty with strong adhesion

flue gas composition

flue gas temperature

6 Composition of waste heat power plant

1) thermal system: waste heat boiler, steam turbine generator unit, condenser, temperature and pressure reduction device, steam turbine bypass system, regenerative bypass system, feed water heating device, feed water pump, valve, pipeline, etc

waste heat boilers and steam turbines in thermal systems are key equipment for power generation

2) flue system: main flue, bypass flue, flue gate, etc

the design of the flue system should consider the production characteristics of the glass furnace. First, the boiler and power generation system can be stopped for maintenance, but the flue gas in the kiln must be discharged normally; Second, the waste heat boiler and induced draft fan cannot produce large fluctuations in the kiln pressure control of the glass furnace during operation/shutdown or switching; third, the requirements of flue gas desulfurization and denitration should be considered

flue system diagram

4) chemical water system: chemical water treatment device, deaerator, make-up pump, etc

5) electrical system: high voltage system, low voltage system, DC system, synchronizing device, protection device, etc

6) control system: DCS system

7. Effect of waste heat power generation of glass furnace

income and cost calculation of waste heat power generation of glass furnace

I. income calculation

rated power generation: 3000kW

annual operating hours: 7200 hours

annual power generation: 1.73 × 107kwh

annual power supply: 1.56 × 107kwh (10% of self consumption)

annual income of waste heat power generation: 10.14 million yuan, opening a new era for domestic injection molding machines (the purchase price is calculated at 0.65 yuan/kWh)

II. Calculation of operating costs

personnel costs: 20 people × 50000 yuan/person year =1million yuan/year

depreciation and amortization fee: 1.8767 million yuan/year

of which

equipment depreciation: 950000 yuan/year (depreciation life: 20 years)

Construction depreciation: 106700 yuan/year (depreciation life: 30 years)

amortization: 820000 yuan/year

water fee: about 600000 yuan/year

electricity fee: self use electricity has been deducted from the income

drug fee: about 200000 yuan/year

total annual operating expenses: 3.6767 million yuan/year

III. investment payback period and power generation cost

investment payback period: about year

power generation cost: about 0.23 yuan/kWh

at present, China has a float.There are more than 240 French lines, with an annual energy consumption of about 12million tons of standard coal, If waste heat power generation is adopted, about 1million tons of standard coal can be saved and 2.8 million tons of CO2 gas can be reduced annually

the above is for a float glass production line. At present, compared with 10 years ago, the scale of glass kilns and the number of glass production lines in glass enterprises are increasing, so the waste heat of two or more glass kilns can be used to generate electricity together, so as to better reflect the economy of waste heat power generation

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