Decarbonization of the chemical industry: key technologies for decarbonizing process heat and feedstock.

The decarbonization of the chemical industry It requires addressing two interconnected operating fronts: the replacement of fossil fuels dedicated to generating process heat and the transformation of fossil raw materials (feedstocks) that constitute the basis of their products. Achieving climate neutrality in this sector requires combining energy efficiency, low and medium temperature electrification, continuous bioenergy, renewable hydrogen, raw materials of biogenic or recycled origin, circularity of polymers and technologies for capture and use of CO2 (CCU).

What you should know about the decarbonization of the chemical industry:

• Unlike other sectors, 60% of the chemical industry’s footprint comes from thermal energy (heat and steam), while the remaining 40% corresponds to the use of oil and natural gas as a chemical raw material or process reactions.
• The ideal strategy to transform a chemical plant follows the rule “First reduce energy demand, then replace energy vectors and finally address raw materials and residual emissions”.
• For the generation of saturated and overheated uninterrupted steam (24/7) in reactors and distillation columns, the industrial biomass is the mature solution that eliminates up to 100% of the thermal scope 1 without compromising production.
• The use of biogenic biomass, recycled plastic and CO2 captured together with renewable hydrogen makes it possible to decouple the synthesis of organic molecules (methanol, ammonia, polymers) of virgin hydrocarbons.
• Through EESCO models, chemical companies can renovate their boiler rooms and cogeneration plants without providing initial capital, financing the facility with the energy savings generated.

Why is it difficult to decarbonize the chemical industry?

Decarbonizing the chemical industry has a higher level of complexity than other industries due to specific structural and engineering factors:

• High energy intensity: It requires a massive and uninterrupted supply of electrical and thermal energy to operate continuous plants.
• Multi-level thermal demands: Requires extremely wide temperature ranges, from 100ºC for cleaning and process fluids, up to more than 900ºC in cracking ovens (Cracking).
• Dual dependency on fossil fuels: Hydrocarbons not only provide energy for combustion, but also act as the primary source of carbon and hydrogen to synthesize plastics, fertilizers, solvents and drugs.
• Inherent process emissions: Various chemical reactions directly release CO2 as an inevitable byproduct of molecular transformation, regardless of the energy source used.
• Long asset life cycles (Capex): Chemical plants operate with assets designed for useful lives between 30 and 50 years old, which makes it difficult to replace untimely technology without a scheduled stop plan.

What emissions are to be reduced in the chemical industry?

To structure the mitigation strategy in a chemical complex, emissions must be classified according to their operational origin:

Emissions derived from energy consumption

They represent the largest volume of scope 1 and 2. They come from the combustion of natural gas, fuel oil or coal in process steam boilers, refraction ovens, dryers and thermal reactors.

Emissions associated with raw materials

They arise when molecules of fossil origin (such as methane to produce hydrogen via reformed or naphtha for ethylene) decompose or release carbon in the final phase of life of the synthetic product.

Emissions from chemical processes

generated by the very physicochemical transformation of the reagents (as in the calcination or the synthesis of certain organic intermediaries), where CO2 is an inevitable chemical by-product.

Indirect emissions

associated with the carbon footprint of electricity purchased from the network (Scope 2) and the extraction, refining and logistics transport of raw materials acquired to third parties (Scope 3).

How to decarbonize the process heat of the chemical industry?

The process heat represents about 60% of the energy demand of a chemical plant. Its decarbonization requires applying solutions adapted to each temperature range:

Improve energy efficiency before replacing fuels

The first step is to optimize the thermodynamics of the complex: reorder thermal integration through composite curves (Pinch technology), recover steam condensates, isolate collectors and eliminate leaks in the distribution networks. If you are looking to delve into this previous phase, you can consult our analysis on industrial energy efficiency.

Biomass to generate industrial heat

For continuous thermal processes that require massive flows of saturated or superheated steam at medium-high pressures and temperatures 200 – 500 ºC), industrial biomass is the most mature and competitive renewable technology. Replacing natural gas boilers with proximity woody biomass eliminates up to 100% of direct CO2 emissions of thermal origin.

Process heat electrification

Ideal for low and medium temperature thermal requirements (<150-200 ºC). The integration of high-temperature industrial heat pumps, electric boilers of electrodes or induction heating systems replaces gas combustion in auxiliary areas and technical rooms.

Renewable hydrogen for high temperature processes

In cracking furnaces or thermal reactors that exceed 800 -1,000ºC, the green hydrogen produced by electrolysis fed with renewable energy acts as a high energy density fuel to replace natural gas.

How to decarbonize the raw materials of the chemical industry?

Decarbonizing the input matrix means replacing carbon and hydrogen of fossil origin with carbon neutral alternatives:

Replace fossil raw materials with renewable raw materials

the concept of Renewable FeedStocks It involves using biogenic carbon, organic by-products such as biochar or CO2 captured to synthesize basic chemical blocks (ethanol, ethylene, propylene) without extracting new subsoil hydrocarbons.

Renewable hydrogen as chemical raw material

Hydrogen is not just an energy vector; It is the main chemical input for the manufacture of ammonia (axis of the fertilizer industry), methanol and hydrotreatment processes in the refinery. Replacing gray hydrogen (via steam-reformed natural gas – SMR) with neutral green hydrogen massively eliminates process emissions.

CO2 captured as raw material (CCU)

carbon capture and utilization technology (carbon capture and use) allows the use of CO2 captured in the chimneys of the plant or adjacent industries to reintroduce it as a reagent together with green hydrogen, producing e-methanol, synthetic polymers or sustainable fuels (E-Fuels).

Biomass and raw materials of biogenic origin

The use of second generation biomass (agricultural, forestry or industrial waste that does not compete with food) allows extracting lignin, cellulose and sugars for the chemistry of specialties and bioplastics, demanding compliance with traceability and sustainability schemes such as Network Directive II and SURE certificate.

Recycled raw materials and circular economy

Chemical recycling (pyrolysis, gasification or depolymerization) converts non-mechanically recyclable plastic waste into pyrolysis oil or synthesis gas, replacing virgin naphtha at the headwaters of the crackers.

What technologies are key to decarbonizing the chemical industry?

Below are the main technological alternatives according to their field of application in the plant:

What decarbonization technology does a chemical plant need?

There is no single universal technology applicable to the entire chemical industry. Selecting the optimal technological matrix requires auditing the energy and industrial profile of each production center:

1. Analyze the thermal profile of the plant: Map the heat demand curve broken down by temperature ranges and vapor pressures required by the reactors.
2. Identify electrified processes: Isolate low-temperature thermal demands that can be covered with high-efficiency heat pumps.
3. Detect biomass potential: Assess the feasibility of installing biomass plants to cover the main thermal base of uninterrupted steam (24/7).
4. Analyze hydrogen consumption: Determine the volume of hydrogen consumed as reagent or fuel to plan its replacement by green hydrogen.
5. Identify process emissions and inputs: Differentiate what percentage of the emissions come from the burning of fuel compared to those generated by the decomposition of fossil raw materials.
6. Compare Economic Viability (Capex/Opex): Evaluate the cost of abatement per ton of CO2 avoided in each technology before allocating the capital.

How to combine technologies to decarbonize a chemical plant?

The transformation of a chemical complex should be considered as a hybrid and sequential strategy where each technology covers a specific requirement:

• Energy Efficiency + Heat Recovery: It is applied in the first instance to reduce the base demand of the plant.
• Biomass + process steam generation: It covers the core of continuous thermal consumption for reactors and distillation columns, providing predictable stability and costs. To see how this solution is articulated in high-efficiency plants, you can consult our article on cogeneration.
• Electrification + Renewable Electricity: It is intended for auxiliary services, pumping, compression and low-enthalpy heat generation.
• Renewable Hydrogen + High Temperature Processes / Synthesis: It is reserved for very high enthalpy reactors or as direct raw material in ammonia and methanol.
• Alternative raw materials + circular economy: It is introduced into the formulation phase to replace oil naphthas with chemical recycling oils or biocarbon.
• CO2 Capture (CCUS): It is installed in the final stage on the chimneys to capture residual emissions from process or inevitable combustion.

What processes in the chemical industry have the greatest decarbonization potential?

Technological interventions achieve the greatest environmental impact when they act on the following manufacturing nodes:

• Centralized steam generation: Replacement of natural gas, fuel or coal boilers by biomass or biogas plants to supply the plant’s steam distribution networks.
• Heating of heat reactors: Replacement of fossil thermal fluids by thermal oil generated with renewable biofuels or electrification.
• Distillation and separation columns: Integration of reboilers fed by biomass steam and heat pumps from Mechanical Steam Recompression (MVR).
• Industrial drying of polymers and salts: Accommodation of dryers by hot air recovered or generated by bioenergy.
• Industrial hydrogen production: Conversion of methane reforming (SMR) plants to renewable energy powered electrolysis.
• Petrochemical Cracking: Development of electric or biogas/hydrogen powered furnaces for naphtha pyrolysis.

What role does biomass have in the decarbonization of the chemical industry?

Industrial biomass plays an irreplaceable role in the chemical industry due to its ability to supply massive and continuous thermal energy in a manageable way.

Replacing fossil fuels to generate steam

Unlike intermittent renewable sources, biomass plants guarantee the generation of saturated steam at the continuous pressures required by chemical plants that operate 24/7, disengaging the bill from the volatility of natural gas. You can expand information about this vector in our specialized post on industrial biomass.

Real projects in the chemical sector

An example of a large-scale reference is the project developed under the industrial decarbonization Perte in Solvay For ENSO, where a high-efficiency biomass cogeneration plant allows the use of fossil fuels in the Torrelavega chemical complex to be replaced, ensuring the steam supply and massively trimming the direct environmental footprint.

Sustainable and traceable biomass guarantee

In order for the biomass to maintain its consideration of neutral fuel in CO2, the provisioning of solid biofuel must certify its sustainable origin and wasteland. At ENSO we support this management as the second company in Europe to obtain the accreditation of the SURE scheme under the Network II directive.

What role does renewable hydrogen have in the chemical industry?

Renewable hydrogen can be considered as an essential energy and chemical vector to decarbonize those processes of the chemical industry that do not support direct electrification. 

On the one hand, it acts as clean raw material Essential in the synthesis of key molecules such as ammonia, methanol, and in desulfurization operations in refineries. On the other hand, it works as High thermal density fuel For very high temperature burners where high radiation flames are required. 

However, its massive deployment is currently facing severe technical and economic limitations, highlighting its high production cost per kilogram, the efficiency losses inherent to the electrolysis process and the logistic complexity associated with storage and transport at high pressure. 

Can CO2 capture decarbonize the chemical industry?

Carbon capture, utilization and storage technologies (CCUS) should be understood as a complementary solution focused on managing process emissions that are difficult to avoid through energy or efficiency:

• Process emissions capture: Chemical absorption (amines) of exhaust gases from reactors where CO2 is inevitably released and other capture technologies.
• Utilization of captured CO2 (CCU): Integration of CO2 with green hydrogen to synthesize polymers or renewable methanol.
• When to use CCU: Mainly in the final remaining phase, after having exhausted the possibilities of energy efficiency, electrification and substitution by biomass.

How to create a decarbonization plan for a chemical industry?

The design of the roadmap of a chemical plant must be structured in logical phases of execution:

1. Analyze consumption and emissions: Calculate the carbon footprint of scopes 1, 2 and 3 according to the how to calculate and reduce the carbon footprint in the industry.
2. Identify critical processes: Classify the points of consumption according to their temperature and if their emissions are energy or raw material.
3. Reduce demand and recover heat: Implement thermal integration measures and optimization of steam networks.
4. Electrify viable processes: Replace low-enthalpy thermal consumption with heat pumps.
5. Replace fossil fuels with biomass: Replace gas boilers with biomass plants for the continuous steam thermal base.
6. Decarbonize raw materials: Introduce inputs of biogenic origin, recycled or green hydrogen.
7. Manage residual emissions: Evaluate the integration of CO2 capture in specific focuses.
8. Monitor and audit KPIs: measure progress according to the methodology of the industrial decarbonization plan.

What are the benefits of the decarbonization of the chemical industry?

• Structural reduction of CO2 emissions: Elimination of environmental liabilities from scope 1 and 2.
• Shielding against the price of gas and emission rights: Direct abolition of payment for emission rights in the EU ETS market. To analyze the economic impact of this armor, you can read our post about the economic benefits of industrial decarbonization.
• Compliance with regulatory regulations: Adaptation to the requirements of the Industrial Emissions Directive and the CSRD Sustainability Directive. To delve into the current requirements, consult the Industrial decarbonisation regulations in Spain.
• Opening of new ESG markets: Preferred positioning as a supplier of low-carbon chemicals and polymers for the automotive industry, packaging or pharmacopoeia.

What challenges does the decarbonization of the chemical industry have?

• Required Capital Investment (CAPEX): Need to finance the substitution or adaptation of large boiler and reactor rooms.
• Availability of clean vectors: Ensure continued supply of certified biomass or green electric power at competitive prices.
• No-stop integration: Plan engineering modifications during scheduled maintenance stops to prevent production losses.
• Preservation of international competitiveness: Maintain reduced operating costs (OPEX) to compete in a global relocated market.

How can ENSO help decarbonize a chemical industry?

On ENSO We act as a technological, operational and financial partner specialized in the energy transformation of industrial complexes:

• Energy analysis and thermal diagnosis: We evaluate the mass and energy balances of your plant to quantify the potential for substitution of fuels.
• Custom biomass and cogeneration projects: We design and install renewable thermal power plants adapted to the vapor pressures and temperatures of your chemical process.
• Financing under ESA model: through our Esco industrial model, we assume 100% of the investment necessary to renovate your boiler rooms, charging only for the clean thermal energy supplied at a predictable rate.
• Guarantee of supply and maintenance: We manage the continuous technical operation of the plant and the global logistics of sustainable biofuel to ensure an uninterrupted thermal supply.

If you want to analyze the feasibility of a thermal project to decarbonize your chemical plant, our team of engineers can develop a personalized technical study.

Frequently asked questions about the decarbonization of the chemical industry

What role does biomass have in the chemical industry?

It supplies uninterrupted thermal energy (24/7) in the form of process steam at high pressures and temperatures, eliminating Scope 1 CO2 emissions in a manageable and immediate way.

Can renewable hydrogen be used as a chemical raw material?

Yes. It is the fundamental input for producing green ammonia, synthetic methanol and for refining and hydrotreating processes of basic chemicals.

What role does electrification have in the chemical industry?

It allows to decarbonize low-temperature thermal consumption by means of heat pumps and to supply with renewable energy the mechanical operations of pumping, agitation and compression.

When is it necessary to use CO2 capture (CCUS)?

In the final phase of the decarbonisation strategy, on residual process emissions or chemical reactions where there is no technological alternative to avoid direct release of CO2.

How is the CO2 reduction of a decarbonisation project calculated?

Multiplying the volume of fossil fuel eliminated or replaced by its corresponding official emission factor, discounting the residual emissions associated with the new technology.