Hydroprocessing Associates is a global full service catalyst and reactor maintenance company with facilities strategically located around the world in order to meet industry demands. Our state-of-the-art equipment, trained workforce, and the ongoing improvement of our life support systems and operating procedures allows for safe project execution in a timely and efficient manner. Over the years we have served countless industries and clients. In the process we have successfully developed specialized equipment and techniques to effectively unload catalyst for various reactors and processes.

Our core business focuses on offering specialized equipment and personnel for the purpose of providing niche reactor services to a broad range of industries including oil & gas, exploration & refining, petrochemical, mining, fertilizer plants, power plants, and utilities. Additionally we provide specialized internal repairs and catalyst dense loading services.

With the sole license to a catalyst dense loading device designed by Chevron, further improved by HPA, and registered as the HYDROPAC®, Hydroprocessing Associates has become the preferred vendor for dense loading services throughout the industry. Our work is usually required during plant shutdowns as well as during emergencies and online reactor problems such as high delta pressure. HPA is globally positioned in Singapore and the United States of America. Therefore, we can offer our services virtually anywhere in the world at a moment’s notice.


HPA (S) PTE LTD, formerly a reactor maintenance division of VAC-TECH ENGINEERING PTE LTD, built a reputation for completing major Hydrocracker and RDS unit turnarounds faster and safer than previous contractors. Due to that success, HPA (S) PTE LTD was invited, by Chevron, to unload and dense load a reactor in Texas. This particular reactor had never run at full capacity with increased catalyst attrition due to mal-distribution.

HPA (S) PTE LTD, better known in the industry as HPA, teamed up with a local US catalyst handling company, and together they successfully completed turnaround and reactor runs to better than expected output. Many of these runs still hold superior today. As a result of these impressive runs, word began to travel amongst US catalyst turnaround groups as HPA’s superior services became the talk of the industry. These groups were so impressed that an article was published in Hydrocarbon Engineering Magazine highlighting HPA’s capabilities. This set the stage for HPA to enter the US market on its own under the business name of HYDROPROCESSING ASSOCIATES, LLC.


HPA is a diversified and integrated service provider with an unparalleled reputation for handling all types of reactors in the oil industry throughout not only the United States but also in Singapore, Malaysia, Korea, Kuwait, and Argentina just to name a few. Our in-depth local knowledge of operating conditions and the candid ability to develop strong relationships with all local and government bodies ensures your best interests are maintained at all times.

HPA has a long history in catalyst handling and dense loading technology having worked closely with ChevronTexaco in various locations around the globe, including the United States, Argentina, and Asia. Having worked on catalyst change-outs, in particular the dense loading of Chevron catalysts and Chevron reactor designs, HPA thoroughly understands the strict requirements around catalyst loading.

We thrive on challenging projects, and if a job is worth doing it’s worth doing right!

Global Team Members
Global Man-hours Safely Worked
Global Projects Completed


Hydroprocessing Associates is well positioned within this unique industry, and we plan to maintain our highly respected and personal reputation with not only our knowledge and skilled workforce, but also our loyalty and commitment to excellence.

By constantly broadening our knowledge of the industry and passing on these skills, we have acquired a vast portfolio and decades of experience in the petrochemical industry. We make it our mission and goal to forge a name for ourselves that can only be associated with Quality, Safety, Customer Care, and Innovation!


We are committed to the safety of our people, the environment, provision of excellence, sustainable growth and continued employment and development of our staff and surrounding communities. We will strive to maintain and develop our profile as a highly reputable and specialized reactor maintenance company.

“Nothing in the world can take the place of persistence. TALENT will not; nothing is more common than unsuccessful men with talent. GENIUS will not; unrewarded genius is almost a proverb. EDUCATION will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent.” – Calvin Coolidge

Meet the HPA Executive Team

Peter W. Thew
Peter W. ThewChief Executive Officer
Sam Ho
Sam HoVice President
Doug McDaniel
Doug McDanielChief Operating Officer
G. Brad Alidor
G. Brad AlidorChief Financial Officer

We are a global full service reactor & refinery maintenance company!

We emphasize Quality, Safety, Customer Care and Innovation in our work.


 HPA is committed to continuing to maintaining and improve its quality management system to provide quality assurance and preserve the integrity of every job. This commitment is validated by the accreditations and certifications maintained by HPA, all of which are reviewed and audited annually.


Safety is our number one priority, and we are committed to an “incident free work environment”. Through our proactive Safety Program, potential hazards are identified, evaluated, and effectively controlled or eliminated to prevent incidents and related consequences.

Customer Care

At HPA we not only see our clients simply as a customer, we also consider them to be partners who share a common goal of completing successful, safe, and efficient reactor turnarounds. The key to HPA’s success has been our commitment to building strong and lasting relationships with our customers.


HPA is always looking for the next opportunity not only in terms of the next project but in the way we perform our services as well. Focus and attention to detail results in innovation, which is apparent in both HPA’s HYDROPAC® technology and foresight to acquire life support system manufacturer, Breathing Systems, Inc.

“Providing niche reactor services to a broad range of industries.”

Contact Us