The "two lows" of coal-to-ethylene glycol are not dreams

On February 11 this year, the National Development and Reform Commission and other four departments jointly issued the "Implementation Guide for Energy Conservation and Carbon Reduction Renovation and Upgrading in Key Areas of High Energy Consumption Industries (2022 Edition)", requiring that by 2025, the energy efficiency of the three major coal-to-methanol, coal-to-olefins and coal-to-ethylene glycol industries should reach 30%, 50% and 30% respectively, and the production capacity below the benchmark level should be basically cleared
.

If you look at it from another angle, it can also be said that the energy efficiency of these three major coal chemical industries is not satisfactory
.
Among them, the current energy efficiency of the coal-to-ethylene glycol industry is only 20% of the production capacity of the benchmark level, the production capacity of energy efficiency below the benchmark level is as high as 40%, and the water consumption and carbon dioxide emissions remain high, which is the first
of the "two highs" in the three major coal chemical industries.

However, this status quo has been challenged
.
Duan Libo, deputy general manager of Shaanxi Weihe Coal Chemical Group Co.
, Ltd.
, said that as long as they dare to try, continue to upgrade technology and optimize the system, coal-to-ethylene glycol can not only achieve the 2025 energy conservation and carbon reduction goals, but also hope to achieve low-carbon green development, changing "two highs" to "two lows"
.
Where does Duan Libo's confidence come from? The reporter interviewed him
.

Q The vast majority of coal-to-ethylene glycol companies feel pressured by the status quo of "two highs", why are you so optimistic?

Duan Libo

Because we are currently working on energy conservation and carbon reduction, and it is effective
.

Coal-to-ethylene glycol is an emerging coal chemical industry
.
Although after 12 years of development, everyone's main energy is focused on 3 aspects: opening up the process and verifying the feasibility, stability and advanced nature of the process technology of different manufacturers; on projects and expansion of production capacity; Benchmark the oil route ethylene glycol, improve and enhance product quality, in order to seize the market and gain a firm foothold
.
In other words, for more than a decade, the coal-to-ethylene glycol industry has mainly solved the problem of how to survive, is extensive development, and has no time to take into account system optimization, energy conservation and carbon reduction and high-quality development
.
Under the pressure of the national energy-saving and carbon reduction policy and market mechanism, it is inevitable to completely remove the "two highs" hat in the later stage
.
Weihe Binzhou Chemical Co.
, Ltd.
(hereinafter referred to as Weihe Binzhou Company) 300,000 tons / year coal-to-ethylene glycol project under Weihua Group Company has and will continue to strive to practice "two highs" to "two lows"
.

Q.
Tell me more about how you did it? What results have been achieved?

Duan Libo

Our 300,000 tons/year coal-to-ethylene glycol project is the first ethylene glycol plant
in Shaanxi Province.
With a total investment of 5.
406 billion yuan, the project started construction in May 2017, completed the commissioning in July 2020, opened the whole process and produced high-grade ethylene glycol products on February 9, 2021, and then transferred to trial production
.
Until now, this unit has set the best record
for the test operation of similar devices.

When we planned this device, we took into account the "two supremes" problem
.
Therefore, in the later stage, all aspects have made preparations
for how to reduce the "two highs".
Among them, the synthesis and rectification of dimethyl oxalate adopts the patented technology of Japan Ube Corporation; The synthesis and distillation of ethylene glycol adopts the patented technology of Japan High Chemical Company; Air separation unit complete set introduction method Air Liquide technology; Coal gasification adopts the pressurized gasification technology of GE 6.
5 MPa coal water slurry; the purification adopts the low-temperature methanol washing and purification technology of Dalian University of Technology; the molecular sieve pressure swing adsorption and hydrogen production adopts the process technology of Southwest Chemical Research and Design Institute Co.
, Ltd.
; the carbon monoxide separation adopts the cryogenic separation technology of Linde Company of Germany.
.
.
.
.
.
Realistically, the energy consumption and water consumption of these patented technologies are currently the lowest in the
world.
Therefore, after the device is completed and put into operation, the reaction conversion rate, raw materials and public works consumption, and product quality of the device have all ranked among the advanced level of the
industry.

Good device technology is an objective condition, and it really depends on ourselves
to open well.
From the day we started driving, we tightened the string of energy conservation and carbon reduction, and continued to carry out technological upgrades and energy conservation and emission reduction optimization and transformation
.

For example, we have installed tuning technology and optimized control technology systems for boilers and key process units, realizing automatic control
of the whole process.
It not only ensures the stable and full operation of the plant, improves the marginal benefit, but also greatly improves the energy utilization rate and reduces emissions
.
According to the assessment of the energy efficiency department, this alone can reduce fuel coal consumption by 6,000 tons per year, reduce sulfur dioxide emissions by 57.
6 tons, carbon dioxide by 12,250 tons, and soot by 1,200 tons
.

For another example, through refined management, we strengthen process control, increase the concentration of coal water slurry from 59% to more than 62%, and continue to implement technical transformation of the gasifier burner, while ensuring that the effective gas content of the gasifier outlet gas exceeds 80%, the residual carbon rate in the gasification furnace slag is reduced to less than 3%, reducing the consumption of raw coal by 20,000 tons per year, increasing the output of ethylene glycol by 7,000 tons, and saving 20 million yuan
in cost and efficiency.
Through the optimization of water system and technological upgrading, we will promote the resource-based cascade utilization of rich production capacity of the reclaimed water reuse system, saving 700,000 cubic meters of water per year, which is equivalent to a decrease of 2.
5 tons of water consumption per ton
of products.

For another example, according to the operation of the device, after a large number of observations and demonstrations, we boldly implemented the ethylene glycol liquid phase hydrogenation technology reform, adding 24,000 tons of polyester grade ethylene glycol every year, with a profit increase of 14.
4 million yuan
.
In response to the pressure difference waste of about 3.
6 MPa in methanol-rich liquid in low-temperature methanol washing units, we have added differential pressure generator sets to generate more than 1.
4 million kWh of new electricity per year
.
With more than 20 years of experience in the operation and management of coal water slurry gasifier by the team, we use drying technology to treat the gasification fine slag, so that its water content is reduced from 50% to 30%, and then sent to the boiler for combustion, which not only saves slag discharge and transportation costs, but also saves about 4,000 tons of coal and reduces carbon dioxide emissions by about 3,000 tons
per year 。 According to rough statistics, in less than two years, including the upgrading and transformation of the gasifier burner, the heat recovery of steam condensate, the differential pressure generation of the process medium, the comprehensive utilization of gasification fine slag, the frequency conversion control transformation of the fan, the refining and recovery of by-products of the ethylene glycol device, the photovoltaic power generation, the process waste heat Rankine cycle power generation, the boiler fly ash residual carbon upgrading and transformation, the refining and recovery of Chi release hydrogen and other technical reforms, innovation, optimization and efficiency improvement activities have exceeded 400 times (places).

These technical reforms may not be revolutionary to look at, but the sand is gathered into a tower, every detail is energy saving and carbon reduction, and the overall "two highs" of the device naturally come down
.

At present, the comprehensive energy consumption of this ethylene glycol device ton product of Weihe Binzhou Company has dropped to 682 kg standard coal / ton, which is only 68.
2% of the latest 1000 kg standard coal / ton of the industry energy efficiency benchmark value, and the water consumption of the ton product is less than 12 tons, which is 5 tons / ton lower than the industry benchmark value, and all pollutants have achieved ultra-net emissions
.
Among them, the emissions of nitrogen oxides, particulate matter and sulfur dioxide in the boiler flue gas were stable at 15 mg/m3, 1.
5 mg/m3 and 3.
5 mg/m3
, respectively.

Q Congratulations on really turning "two highs" into "two lows"
.
Do you think there is still room for energy saving and carbon reduction in this device?

Duan Libo

And also! As Yang Zhaoqian, chairman of Shaanxi Coal Group, said, management is like twisting wet towels, as long as you continue to work hard to twist, you can always wring out the water
.
In fact, at present, this ethylene glycol plant is implementing eight major energy-saving and carbon reduction technical transformation projects:

The first is a larger-scale steam condensate heat recovery power generation and by-product low-grade steam comprehensive utilization project
.
It is planned to invest about 20 million yuan to use Langken cycle power generation technology to recover the steam condensate heat of the ethylene glycol device and then generate electricity
.
After the implementation, the annual power generation will exceed 14.
4 million kWh, reducing the amount of circulating water consumption by 1,000 tons per hour
.

The second is the process air pressure differential power generation project
.
Using the pressure difference of 5.
5 MPa wasted by most enterprises to 3.
5 MPa process gas, the annual power generation can be increased by 4.
7 million kWh
of new power generation through the process gas differential generator set.

The third is the rich nitrogen pressure energy expansion power generation project
.
Using the abundant low-pressure nitrogen gas during normal operation of the device, the low-quality waste heat that has not been recovered in the nested plant area is used for expansion power generation and heat and cold recovery
.
After implementation, it will generate 3.
2 million kWh of electricity per year
.

The fourth is the by-product dimethyl carbonate refining and improvement project
.
It is expected that the annual increase of high-purity dimethyl carbonate is 15,000 tons, and the annual cost saving and efficiency increase will be 45 million yuan
.

Fifth, the overall optimization of the circulating water system energy-saving renovation project
.
At present, we are actively conducting research and exploring and optimizing the program, and we will pay close attention to promoting
it when the time is ripe.

Sixth, the use of thermal clamping technology to optimize the heat transfer of the distillation system and reduce steam consumption
.

The seventh is to optimize and transform the distillation system to improve the efficiency of heat transfer and mass transfer and separation, and reduce steam consumption
.

The eighth is the pilot and industrialization application project
of decarbonizing methyl formate to methanol and carbon monoxide.
This technical modification action is relatively large
.
The conventional disposal of methyl formate by-products of ethylene glycol plants is to enter the sulfur recovery incinerator for incineration
.
This not only wastes methanol and methyl nitrite, but also has greater safety and environmental risks, which increases environmental investment and operating costs
.
To this end, Weihe Binzhou Company plans to invest more than 20 million yuan, using the domestic leading new process of methyl formate decarbonization to methanol and carbon monoxide, and jointly carry out pilot tests with relevant scientific research institutions to strive to turn methyl formate into treasure
.
After the success of this technological transformation project, it can add 23 million kWh of waste heat, residual pressure and waste cooling power generation every year, reduce the amount of circulating water consumption by more than 8 million tons, and reduce the discharge of salty wastewater by 24,000 tons
.
At the same time, 15,000 tons of high-purity dimethyl carbonate were added, and the consumption of low-pressure steam was reduced by 240,000 tons
.
At that time, the comprehensive energy consumption, water consumption and carbon dioxide emissions of our ethylene glycol plant products are expected to be reduced by more than
10%.

With the sharp decline in production costs, the competitiveness of enterprises will be significantly enhanced
.

Q You did it, do you think the whole coal-to-ethylene glycol industry can do it?

Duan Libo

For coal-based/fuel-based energy and chemical projects, it is not easy to achieve green development, but it is not impossible
.
It is not easy to say that it is not easy, because coal is more carbon and less energy, and the molecules of many chemicals, including ethylene glycol, show the characteristics of more hydrogen and less carbon, and the gas needs to be transformed and purified in the production process to obtain a suitable hydrogen/carbon ratio
.
This transformation process produces a large amount of carbon dioxide
.
In addition, the steam and electricity required for production are basically provided by coal-fired boilers or power stations, and the power and steam production process also emits a large amount of carbon dioxide, so the raw materials, fuels and process technology itself determine that coal-to-chemical chemicals have the characteristics of
high carbon emission and high energy consumption.
It is not impossible to say it, because as long as the cause of high carbon emission and high energy consumption is found, and the right medicine is prescribed, it will alleviate or even eliminate
the disease.

For example, coal-to-ethylene glycol enterprises can support wind power and photovoltaic power generation projects according to the characteristics of renewable resources in the project location, not only can directly replace coal-fired power generation with green electricity, but also use green electricity to produce green hydrogen and green oxygen
by electrolysis of water.
The industrial characteristics of coal-to-ethylene glycol provide a good scenario for the application of green hydrogen, replace the gas conversion to produce hydrogen, and reduce the carbon dioxide emissions in
the production process.
It is also possible to replace coal-fired hot water, steam, and power generation
through solar thermal technology.
For areas rich in biomass resources, it is not only possible to directly replace the boiler coal with biomass to produce steam and generate electricity, but also to provide green steam and green electricity for the device; It can also provide syngas through biomass gasification/pyrolysis technology, reducing or even completely replacing raw coal, and ultimately achieving green and low-carbon development
.
In addition, according to the relevant national policies, renewable energy, including biomass, can not be included in the energy consumption assessment indicators
。 Therefore, after the large-scale use of renewable energy such as wind, light and biomass, the energy consumption of products will naturally drop significantly, thus removing the "two high" hats
.

As far as I know, many domestic energy and chemical enterprises have carried out exploration and attempts
to use renewable energy to produce green electricity, green hydrogen and green oxygen to reduce energy consumption and carbon emissions.
Ningxia Baofeng Energy Group's 200,000 kilowatts of photovoltaic power generation + 20,000 standard square meters / hour electrolysis of water to hydrogen production equipment supporting its coal methanol to olefin project will be completed and put into operation on April 20, 2021, reducing annual coal consumption by about 254,000 tons and carbon dioxide emissions by about 445,000 tons
。 In May 2021, Sinopec Corporation launched its first green hydrogen refining project, the Ordos 20,000 tons/year green electricity hydrogen production project, with an estimated investment of 2.
6 billion yuan, supporting 270 MW of photovoltaic power generation and 50 MW of wind power generation, and after the project was put into operation, it provided 20,000 tons of green hydrogen (220 million cubic meters) per year for the 3.
6 million tons/year coal-to-methanol co-production of 1.
37 million tons/year of coal-to-methanol to olefins plant of Zhongtian Hechuang Energy Co.
, Ltd.
, which greatly reduced the energy consumption and carbon dioxide emissions of coal-to-olefin projects
。 These peers are also our role models
.
Now Weihe Binzhou Company has built a 4 MW photovoltaic power generation project, and there is also a photovoltaic and wind power planning
in the later stage.
These green electricity will all be used by the company and serve as the basis for
the company's future growth and development.
At the same time, we also plan to try to promote the biomass substitution of some coal-fired experiments, investigate biomass gasification/pyrolysis hydrogen production (syngas) to replace part of the coal gasification technology, and create a model project for domestic renewable energy and coal chemical industry coupling to promote the low-carbon green development of coal-to-ethylene glycol projects
.

Q What other advice do you have for the coal-to-ethylene glycol industry?

Duan Libo

First of all, we must face the gap and reality, face up to the industry's own high energy consumption, high emissions, extensive management, poor competitiveness and other deficiencies, carry out energy consumption diagnosis, strengthen daily fine management, aim at advanced cutting-edge technology, continue to carry out full QC group activities and energy-saving and carbon reduction technology transformation, and strive to achieve stable and excellent operation of the device, providing high-quality products
for downstream users.
At the same time, it is necessary to adapt to local conditions and actively couple with photovoltaic power generation/wind power electrolysis of water to hydrogen, solar thermal and biomass substitution of coal, biomass to hydrogen, biomass to syngas and other technologies, to promote technological progress in the industry, energy conservation and carbon reduction, cost saving and efficiency
.
It is believed that as long as we make real efforts, the coal-to-ethylene glycol industry will be able to take off the "two highs" and open up a new path for
low-carbon green development.

(Duan Libo: Senior engineer, deputy general manager of Shaanxi Weihe Coal Chemical Group Co.
, Ltd.
, executive deputy general manager of Weihe Binzhou Chemical Co.
, Ltd.
, has long been engaged in the construction and enterprise management of large-scale coal chemical projects, responsible for the construction, operation and daily management of Weihe Binzhou Chemical Co.
, Ltd.
coal-to-ethylene glycol project energy consumption, water consumption, load rate, carbon emissions and other indicators in the domestic industry leading level)